CAPSTONE DESIGN COURSE
Design of a Tree Pruning Device
Design Team Garth Baker, Pete Colantonio, Dmitry Layevsky Ryan Provencher, Ryan Rafter
Design Advisor Professor Greg Kowalski
Course Instructor Professor Greg Kowalski
Department of Mechanical, Industrial, and Manufacturing Engineering Northeastern University Boston, MA 02115 Design of a Tree Pruning Device
Design Team Garth Baker, Pete Colantonio Dmirty Layevsky, Ryan Provencher, Ryan Rafter
Design Advisor Prof. Greg Kowalski Abstract
The initial specifications of this design project were to design a pruning device that could cut through a three-inch diameter branch that is twenty-five feet above the ground in a reasonable amount of time using a waterjet-cutting device. Additional requirements include that the device have a competitive cost and be safe and easy to use. The team determined that the use of waterjet cutting technology was an infeasible design concept to meet these requirements, because it would take almost two hours to cut through a three inch branch using a pressure washer capable of 3500 psi. To cut a three-inch diameter branch in a reasonable time would require a pressure above 30,000 psi. A shearing device that would be powered by a hydraulic piston was selected as a better and more feasible alternative design solution. The shearing device we designed has hardened steel blades from a Corona® clipper product, and utilizes a hydraulic piston attached to a 29-foot telescoping pole, which is mounted to a tripod .. A telescoping pole, made of Thorne!® carbon fiber and reaching twenty-five feet, is required to meet the second design requirement. The pole needs to extend up to a minimum height of twenty-five feet above the ground while having the capability of comfortably reaching lengths below twenty-five feet. Static analyses were performed and a design methodology was developed for the pole. The analysis of a 29.167- foot telescoping pole with a variable wall thickness and base OD of 3.5 inches and a final pole ODof 2.5 inches yielded approximately a one-inch deflection. Dynamic analysis on the pole design utilizing a spring-mass equivalent system was performed. The effects of swinging the pole and pole oscillations were determined. The best configuration for the pole design is a telescoping pole made with external locking devices between each segment. Due to the weight of the assembly of the device and pole, the pole is mounted to a plain spherical bearing that is press fit into a tripod. This alleviates the operator from holding and maneuvering of the device. This allows for easier use, while designed to prevent tipping and to allow for twelve-feet of lateral movement of the pruning device. The Need for the Project
Provide a tree-pruning device to Tree pruning can be an expensive and dangerous task, for the homeowner prune three-inch diameter and professionals alike. A state of the art tree-pruning device is needed to branches located 25 feet above provide homeowners and professionals with a safe and cost effective way to the ground. prune tree branches that have diameters of three-inches and are located 25 feet above the ground.
The Design Project Objectives
Our design will provide the The device will provide the operator with a safe means of pruning tree operator with a safe. cost branches. Previous methods put the operator near the cut, on top of ladders; effective and ergonomic device our device will allow the operator to remain on the ground while pruning any to aid in pruning trees. branch as high as 25 feet above the ground. The device will be easy to operate; eliminating any motion needed to cut the tree branch, i.e. the pole saw. This reduction of this motion will reduce additional stress on the operator. The device will also be cost effective. The competitive cost of the device will benefit homeowners and lower end professionals alike. The Design Requirements
Allows the operator to remain on The requirements for the device are to cut tree branches that are up to the ground, while cutting three three-inches in diameter at a height of 25ft above the ground. The device inch diameter branches that are avoids any use of vibrating or reciprocating device. The device is 25 feet above of the ground. ergonomically designed so it is easy to maneuver and use.
Design Concepts Considered
We developed two conceptual The use of waterjet technology for pruning trees does not exist on the designs, waterjet and shearing market today. The two concepts for the use of a water jet were a single and a device. Each conceptual design double head nozzle. Both the single and double head nozzle would be had two design concepts. A pole mounted to the branch and a high-pressure flow of water would perform the was required to reach the cut. The double head nozzle would reduce the cutting time by cutting the required height of 25 feet for branch from two sides. The dual head nozzle would also reduce forces on the each concept. pole and operator by spraying in opposite directions. The team performed analytical analysis of what it takes to cut through a three-inch diameter branch using a waterjet. It was determined that due to the high pressure of 30,000 psi required and safety to the operator, it was not feasible to manufacture a waterjet device to prune trees. The cost of creating a pressure this large to perform the cut exceeded the project budget. In addition to the high pressure required there was an issue of reentering the line of cut with a 1-mm diameter nozzle at 25ft above the ground. The shearing concept proved to The second conceptual idea for pruning three in diameter branches was to be the more efficient design use shears. The two concepts that utilized the shearing method were a concept. pneumatic and hydraulic driven piston. The weight limit for the shearing device eliminated the use of a pneumatic driven piston, therefore our shearing device component will utilize a hydraulic driven piston. A telescoping extension pole The ability to cut branches 2:5 feet above the ground introduces the design provides a solution to the height of the pole. The concepts that were considered to situate the pruning device at requirement the required height of 25 feet were a basic pole, a segmented extension pole, and a telescoping extension pole. The telescoping extension pole best suited the need to reach the required 25 feet. The use of the telescoping pole also makes the device more marketable by having the ability to operate at heights between 5 and 25feet. The design of an ergonomic The last sub-assembly designed is an ergonomic tripod. The use of the tripod reduces the force needed tripod removes the weight of the device and pole from the operators hands. It to operate the device. also reduces the force required to maneuver the pole and device.
Recommended Design Concept
The design of our tree Design Description pruning device utilizes a The design that the team proposed to Professor Kowalski, our advisor, hydraulic driven piston that has was a shearing device powered by a hydraulic driven piston, with a hand the pressure supplied by a hand pump located on the ground that will supply the pressure needed to activate pump and that will drive a bypass the piston. The assembly is then attached to the end of a telescoping style steel blade from a extension pole. Due to the weight of the entire device, the pole will be purchased pruning device. The mounted to a tripod. device will be located at the end The blades in the device were removed from a purchased pair of Corona® of a 29-foot telescoping pole, pruners. They are pinned to a square aluminum sleeve with a custom which is mounted to a tripod. designed nut and bolt. The sleeve has an ID of two inches and is 36 inches long to enclose most of the shearing mechanism. The blade arms are then press fit and screwed into extension arms, the purple components in Figure 1. Pinned to the end of the extension arms are hinges, which are pinned to the rod clevis of the hydraulic piston. All of the working arms and extension arms are designed to withstand the required closing force on the blades during the cut, with a factor of safety of three. The piston shaft has a 12 inch stroke length. One end of the hydraulic piston is pinned to the sleeve, allowing room at the end of the sleeve to attach the pole. The hydraulic piston is then attached to a hydraulic hand pump in a closed loop hydraulic circuit. It takes approximately seven pumps on the hand pump to complete a cut on a three inch diameter tree branch. The pressure hose that connects the pump and the piston is then routed down the length of the telescoping extension pole. The aluminum sleeve is then fastened to the telescoping extension pole. The telescoping pole is 29 feet in length with external locking collets for ease of use. Located at 3.5 feet from the base of the pole is the tripod. The tripod consists of a plain spherical bearing press fit into a base plate, which has a triangular shape, with 5 feet extension legs. The spherical plain bearing allows for the positioning of the device, 12 degrees of lateral motion and 360 degrees of rotational freedom. The 12 degrees of freedom gives a 12 feet range of motion to the shearing device at the end of the pole, allowing for 6 foot radius from the tripod center. At the end of two of the legs are two locking casters for transporting purposes. The total weight of the device assembly is approximately 116 lb., which includes the shearing device, hydraulic piston, sleeve, telescoping pole, and tripod. For transporting the Figure 1 - By-pass Blades device,, the shearing assembly is removed from the pole. The effective force of with extension arms carrying the compacted tripod, while rolling on the two casters, will be 40 lbs., which meets ergonomic standards. The analytical investigations that Analytical Investigations were performed on the system The pole analysis was a dynamic process. It required static as well as a included a static and dynamic dynamic investigation. The static analysis was to determine the deflection of deflection of the pole, and the the pole during operation. The dynamic analysis was needed to determine the tipping and counter balance of effect of swinging, or positioning the pole from limb to limb. The static the tripod. analysis consisted of an Excel spreadsheet that calculated the deflection of the pole from horizontal to vertical. The static deflections calculated were based on different weights of the pole and pruning device, and the angle at which it would be operated. Calculating for worst case, horizontal, and taking the weight of the shearing device to be 15 lbs., the static deflection was determined to be 1.015 inches when the device was added to the end of the pole. The deflectiondecreased as the pole was raised to the vertical position. As a recommendation by Prof. Hashemi, the dynamic analysis consisted --- X( c) of modeling the pole and device system as a spring-mass system, as seen in Figure 1. This was done instead of using a software package such as Ansys or Adina. MathCad was used to integrate the formulas for mass equivalence (Meq) and spring constant equivalent (keg) and produce numbers for these --- X(n) constants. This information was used to determine the natural frequency (mn) of the pole which was used in formulating the periodic motion equation (1) for c� --- X(t) the system. 2 d X dx Meq ·- +C ·-+k ·x := o dt eq (1) Figure 2- Spring-Mass cte Damper System In Figure 2, the X( c) represents the maximum distance of compression of the spring, the X(n) is the static equilibrium of the spring mass system, and X(t) is the maximum distance of the spring in tension, which in turn represents the maximum deflection of the pole. Determining the maximum distance the pole would oscillate required the material's damping coefficient. This value is Device very difficult to determine manually; most often, this value is determined with weight physical testing. Since the cost of obtaining the design material was not in our budget, a similar test was performed on our prototype pole. The damping coefficient test was performed using the prototype pole and an accelerometer. Then the damping coefficient of the prototype was used to determine the maximum oscillations of the model pole from the motion equation. The model pole values were then related to the values of the pole design. This allowed the team to obtain a comparison value for the pole design with a maximum dynamic deflection of model pole. The counter balance for the pole and the minimum distance for the pole to cause the tripod to tip were analyzed using Excel. Both values were determined using moment equations about the center of gravity on the pole and the tipping plain of the tripod, Figure 3. Counter In order to reduce the force required by the operator, a counterbalance balance with a weight of 25 lbs. was designed into the base section of the pole. The width of the tripod legs was calculated to be 6ft from end to end, and the Figure 3- height of the tripod is 3.5 ft to prevent the device from tipping over from its Free Body for Counter Balance own weight. The Shear force requirements Experimental Imestigations were determined from an Instron In a published study from an arborist journal, a shear test was performed test, performed with Corona® to calculate the required force to cut through various diameter wooden dowels. blades. The Corona® blades That study was the basis for performing an experimental investigation on the were eventually used to make the shear force required to cut through a three-inch diameter hard wood in a prototype. similar analysis be performed. From this analysis, our shear force experiment was determined. Two fixtures were designed, made, and then setup in the Instron machine to perform the shear test, Figure 4. Then seven different branches were cut from smaller diameter to larger diameter in order. The diameters ranged from .5 inches to three inches. Seven sets of data were collected, each data set containing the same diameter branches cut. This was 10 linear feet of total wood cut through. The cutting force was measured from the Instron as well as the distance traveled. This enabled us to calculate the moment about the pin at any angle of cut. Cutting through 10 linear feet of wood enabled us to analyze the effects that wearing of the blades had on the data. The data remained average for every data set eliminating the effect of blade wearing. Through statistical studies, the worst case moment was determined. Given this, the team could then calculate the required force from the piston to generate a strong enough moment to complete the cut at any angle of cut.
Figure 4- Instron Set up Financial Issues
The design concept raises several The one-time cost of a carbon fiber telescoping extension pole is very cost issues. Production line cost expensive. The team instead, decided to design and build a 1/3 linear scaled is expected to be very expensive, working model of the pole and tripod. In addition, to purchase a piston that and similar to prototype cost. generates a high enough force and meets the weight requirements is very expensive. Instead, a cheaper but heavier piston was purchased to meet the force requirements, in order to build a proof of concept prototype. Recommended Improvements
The design of a hydraulic piston An increase in budget would have allowed for the purchase or design of a made specifically for the function lower weight and smaller piston that could meet the force requirements. The of the shearing device, not an off bypass blades could have also been designed to maximize cutting abilities. the shelf model. Investigate into Also, an intensive search into fibrous material companies may have the specialty fibrous materials to produced a new material, one that would be more beneficial to the design of reduce the weight and cost of the the pole, making it lighter and less expensive than the current design. pole. Although these two things may have helped the design, it would still not produce a marketable device. The cost of the device on the production line would still be too expensive to compete with current pole pruners on the market today. The shear device designed is safer than most pole pruners, but cannot compete with their lower component weights and lower costs. Letter of Transmittal
Date: 6/03/99 To: Professor Kowalski From: Tree Pruning Design Team Subject: Second Quarter Final Report CC: Professor Harper
Dear Professor Kowalski,
The attached report will describe the research and development of the proposed tree pruning device. This is the second of two reports that presents our research and development of our tree-pruning device. This report was authorized by our design advisor Greg Kowalski.
The initial design requirements of this project were to cut a three-inch diameter branch that is twenty-five feet above the ground, with a waterjet-cutting device. There were initial doubts on the feasibility of this device; brainstorming then led to the alternative design concept, a shearing device. Since the beginning of the first quarter, extensive analysis was performed on both the waterjet and shear device concepts. This analysis enabled us to make a design decision to eliminate the waterjet-cutting device from our possible design solutions.
In reality, our design project was three projects in one. We have performed extensive research and analysis on the water-jet technology, telescoping extension poles, and shear cutting technology. The elimination of the waterjet-cutting device allowed us to concentrate on the development of our telescoping pole and shear cutting device.
The design of our tree-pruning device has provided us with a great learningexperience. Not only have we learnedabout the mechanics of waterjet cutting and shear cutting, but also we have learneda great deal about how the design process works. This is valuable information as our college education nears closure.
Best regards,
Tree Pruning Design Team
Garth Baker Pete Colantonio Dmitry Layevsky Ryan Provencher Ryan Rafter
ii Table of Contents
List of Figure ...... VII
List of Tables ...... VIII
Abstract ...... IX
Acknowledgments ...... X
Copyright...... XI
Chapter 1. Introduction ...... 1-1
1.1-T he Need for a New Tree Pruning Device ...... 1-1
1.2-Design Specifications ...... 1-2
1.3- Conceptual Designs of Cutting Mechanisms ...... 1-3
1.4- Plan of Report Development...... 1-4
Chapter 2. Safety ...... 2-1
2.1-Non-Ladder Use...... 2-1
2.2-Avoiding Electrocution ...... 2-3
2.3- Rotating Cutting Mechanisms ...... 2-4
2.4-Injuries Associated with Overexertion ...... 2-3
2.5-Use of ErgGnomic and Human Factors to Avoid Injury ...... 2-4
2.6-Use of a Tripod Assembly ...... 2-5
2.7-Summary of Safety Concerns...... 2-6
Chapter 3. State-of-the-art ...... 3-1
3.1-Introduction to Waterjet Technology ...... 3-1
3.1.1-Waterjet as a Tree Cutting Mechanism ...... 3-1
3.1.2-Types of Available Intensifiers ...... 3- 2
3.1.3-Types of Available Nozzles ...... 3-2
3.1.4-Adding Abrasives to Waterjet...... 3- 2
3.1.5-Use of Pressure Washer to Obtain High Pressure Water...... 3-3
3.1.6 - Conclusion of Waterjet Technology...... 3-4
3.2-Mechanical Cutting Mechanism ...... 3-5
3.3-Saws and Loppers Available on the Market...... 3-9
3.4-Summary of Existing Products ...... 3-1 D
iii 3.5-Existing Poles on the Market...... 3-1 1 3.5.1-Testrite Instrument Company ...... 3-11 3.5.2-Trailblazer Products ...... 3-13 3.5.3-Treasure Valley Supply, Inc ...... 3- 14 3.5.4-Mr. Long Arm, Inc ...... 3-14 3.6-Basic Poles ...... 3-15 3.7-Segmented Extension Poles ...... 3-1 5 3.8-Telescoping Poles ...... 3-16 3.9-T ripods on the Market ...... 3-17 3.10-Results of Findings ...... 3-17
Chapter 4. Waterjet Tree Pruning Device ...... 4-1 4.1-Waterjet Cutting Technology ...... 4-1 4.2-Mechanisms of Cutting Wood with Waterjet Technology ...... 4-2 4.3-Initial Waterjet Design Concepts ...... 4-4 4.4-Waterjet Calculations ...... 4-6 4.5-Conclusion of Waterjet Calculations ...... 4-8 4.6-Industry Concerns...... 4-9 4.7-Elimination of Waterjet Cutting Device ...... 4-9
Chapter 5. Shearing Design Concept...... 5-1 5.1-Design Concepts ...... 5-l 5.1.1-F inal Design Concept...... 5- l 5.1.2-Sleeve Design Methodology ...... 5-3
5.2-Concerns...... 5- 4 5.2.1-Jaxnrning...... 5-4 5.2.2-Overall Weight ...... 5-6 5.2.3-Cutting Torque ...... 5-6 5.2.4-Effective Cutting Diameter ...... 5-7 5.3-Cutting Mechanics ...... 5-7 5.4-Force Requirements ...... 5-8 5.4.1-Instron Fixtures ...... 5-8
iv 5.4.2-Wood Selection & Test matrix ...... 5-9 5.4.3-Wear Effects ...... 5-10 5.4.4-Data Processing ...... 5-10 5.4.5-Maximum Required Force ...... 5-12 5.5-Linkage & Sleeve Analysis ...... 5-14 5.6-Prototype vs. Production ...... 5-19 5.7-Prototype Testing Results ...... 5-19 5.8-Summary of Shearing Device Design ...... 5-21
Chapter 6. Pole Design ...... 6-1 6.1-25ft Requirement...... 6-2 6.2-Material Selection ...... 6-3 6.3-Mechanics of Telescoping Pole ...... 6-3 6.4-Static Deflection Analysis ...... 6-4 6.4.1 -Static Deflection vs. Weight of the Pole ...... 6-6 6.4.2-Static Deflection vs. Weight of the Device ...... 6-7 6.4.3-Static Deflection vs. Angle of Operation ...... 6-9 6.5 -Additional Analysis Required for Pole Design ...... 6- 10 6.5.1-Additional Effects of the Cutting Forces of the Pole ...... 6- 10 6.6.2-Additional Effects of Dynamic Motion on the Pole ...... 6-1 1
6.6-Prototype ...... 6- 13 6.6.1-Scaled Model ...... 6- 13 6.6.2-Analysis ...... 6- 13 6.6.3-Physical Testing for Damping Coefficient ...... 6- 15 6.6.4- Calculating Damping Coefficient & Equation of Motion ...... 6-15 6.7 - Relating the Prototype Pole to the Pole Design ...... 6- 17 6.8- Summary ...... 6-18
Chapter 7. Tripod Design 7.1-Initial Design Concept...... 7-2 7.2- Decision of Tripod Aspects ...... 7-6 7.3-Tripod Criteria ...... 7-6 7.4- Design Components ...... 7-7
v 7.4.1- Design Components (Spherical Plain Bearing) ...... 7-7
7.4.2- Design Components (Telescoping Tripod Legs)...... 7-8
7.4.3- Design Components (LockingDevice for the Pole) ...... 7-8
7.5- Final Tripod Design ...... 7-9
7.6- Tripod Prototype Testing & Evaluation ...... 7- 10
Chapter 8. Conclusion ...... 8-1
8.1-Waterjet Concept Elimination ...... 8- 1
8.2- Shear Cutter Concept...... 8-2
8.3- Pole User Interactions ...... 8-3
8.4- Tripod Assembly ...... 8-5
8.5- Summary ...... 8-6
References Appendix A. Patents Appendix B-1. Pressure Washer Comparison Appendix B-2. Available Shears Appendix B-3. Nozzles Appendix B-4. Poles Appendix C-1. Material Properties "Wood" Appendix C-2. Material Properties Appendix D-1. Waterjet "MathCad" Appendix D-2. Waterjet "Velocity vs. Pressure" Appendix D-3. Cutting of Tensile VVood Appendix D-4. Time to Cut Appendix D-5. Shear Calculations "MathCad" Appendix D-6. Sum of the Forces Appendix E. Email Responses Appendix F-1. Instron Data Appendix F-2. Accelerometer Appendix G. Part Drawings
vi List of Figures
Chapter 2 Safety 2.1 -Safety and height...... 2-2 2.2-Optimal hand positions for holding ...... 2-4
Chapter 3 State of the Art 3.1-Internal mechanism of an intensifier...... 3-2 3.2-How a pressure washer works ...... 3-4 3.3-Cutting styles for shear devices ...... 3-5 3.4-Various shear devices used to increase mechanical advantage ...... 3-6 3.5-Rope level diagram ...... 3-6
3.6-Hand operated hydraulic pruner...... ·...... 3-7 3.7-Gas powered hydraulic pruner...... 3 -7 3.8-Ratcheting tree pruner by Razor-Back ...... 3-8 3.9-Tree pruning system by Corona Clipper ...... 3-8 3.10-250PS hydraulic pole chainsaw by Husqvarna...... 3-10 3.11-Three styles of Testrite locking devices ...... 3-1 1 3.12-External locking device ...... 3-12 3.13-Illustration of external collet locking devices ...... 3-13 3.14-Xtend-A-Pole from Trailblazer products ...... 3-13 3.15-lllu stration of TVS aluminum pole ...... 3-14 3.16-Illustrations of Mr. Long Ann poles ...... 3-15 3.17-Additional illustrations of Mr.Long Arm poles ...... 3-15
Chapter 4 W aterjet Tree Pruning Device 4.1-Waterjet cutting through rope ...... 4- 1 4.2-Waterjet cutting through marble ...... 4- 1 4.3-Waterjet cutting through stainless steel...... 4- 1 4.4-2D cutting table with 8 waterjet cutting heads ...... 4 -2 4.5-Material erosion ...... 4-3 4.6-Waterjet cutting a tree branch ...... 4-4 4.7-Dual nozzle design concept...... 4-5 4.8-Integration of tree branch for cutting speeds ...... 4-8 4.9-Pre ssure vs. cut time ...... 4 -8
Chapter 5 Shearing Device Concept
5.1-Final Design ...... 5-2 5.2-Shear Blades with Custom Nut & Bolt ...... 5-3 5.3-Square Sleeve ...... 5-4 5.4 Knot locations ...... 5-5 5.5-Cutting torque diagram ...... 5-6 5.6-Non-perpendicular cutting ...... 5-7 5.7-Reference data ...... 5-8
Vll 5.8-Instron fixtures ...... 5- 9 5.9-Testing observations of rotten cores ...... 5-1 1 5.10-Trendline analysis ...... 5-1 1 5.11-Conf idence and prediction intervals ...... 5-1 2 5.12- Cutting moment comparison ...... 5-13 5.13-Analysis of Design Components ...... 5- 15 5.14-Analysis of Extension Arms ...... 5-16 5.15-Analysis of Sleeve ...... 5-17 5.16-Picture of Prototype ...... 5-20
Chapter 6 Pole Design 6.1- Telescoping Pole Design ...... 6- 1 6.2-Internal view of telescoping pole with external collet...... 6-4 6.3-A sample of the free body diagrams for the pole deflections ...... 6-5 6.4-Weight of pole and device vs. the deflection in the pole ...... 6-8 6.5-Angle of operation vs. the weight for various angles of operation ...... 6-9 6.6-Spring Mass Damper System for Equivalent System ...... 6-1 1 6.7-Dynamic Response of Pole ...... 6- 16
Chapter 7 Tripod Design 7.1-Moment Equations ...... 7-2 7.2-Force vs. Counter Balance Moment Equations ...... 7-3 7.3-Tipping Plane Diagram ...... 7-4 7.4-Tipping Plane Distance ...... 7-4 7.5-Transportation F.B.D ...... 7-5 7.6-Plain Spherical Bearing ...... 7-8 7.7-Closed Tripod Assembly ...... 7-9 7.8-Open Tripod Assembly ...... 7-10 7.9-Tripod & Telescoping Pole Assembly ...... 7-11
List of Tables 3.1-Abr asives vs. waterjet...... 3-3
viii Tree Pruning Devi<�e
Abstract
The initial specifications of this design project were to design a pruning device that could cut through a three-inch diameter branch that is twenty-five feet above the ground in a reasonable amount of time using a waterjet-cutting device. Additional requirements include that the device have a competitive cost and be safe and easy to use. The team determined that the use of waterjet cutting technology was an infeasible design concept to meet these requirements, because it would take almost two hours to cut through a three inch branch using a pressure washer capable of 3500 psi. To cut a three-inch diameter branch in a reasonable time would require a pressure above 30,000 psi. A shearing device that would be powered by a hydraulic piston was selected as a better and more feasible alternative design solution. The shearing device we designed has hardened steel blades from a Corona® clipper product, and utilizes a hydraulic piston attached to a 29- foot telescoping pole, which is mounted to a tripod. A telescoping pole, made of Thornel® carbon fiber and reaching twenty-five feet, is required to meet the second design requirement. The pole needs to extend up to a minimum height of twenty-five feet above the ground while having the capability of comfortably reaching lengths below twenty-five feet. Static analyses were performed and a design methodology was developed for the pole. The analysis of a 29.167-foot telescoping pole with a variablewall thickness and base OD of 3.5 inches and a final pole OD of 2.5 inches yielded approximately a one-inch deflection. Dynamic analysis on the pole design utilizing a spring-mass equivalent system was performed. The effects of swinging the pole and pole oscillations were determined. The best configuration for the pole design is a telescoping pole made with external locking devices between each segment. Due to the weight of the assembly of the device and pole, the pole is mounted to a plain spherical bearing that is press fit into a tripod. This alleviates the operator from holding and maneuvering of the device. This allows for easier use, while designed to prevent tipping and to allow for twelve-feet of lateral movement of the pruning device.
ix Acknowledgements
The members of the tree-pruning group would like to thank Professor Messac for his constant encouragement and instruction during the initial design process. We would like to give special acknowledgement to Professor Kowalski for his professionalism and guidance as our design advisor who has pushed us to our full potential and for taking over the course as instructor. We would also like to thank Professor Isaacs, Professor Harper, Professor Adams, Professor Hashemi, Professor Benneyan, Professor Beverly Yeager,
Professor Murphy, Mr. Jon Doughty, Mr. Richard Walen and Mr. Matt Ulinski for their assistance. We would also like to thank Mr. Ray Laliberte for his assistance in making a nozzle for the waterjet test.
X Copyright
"We, the team members,
I fi /
Garth Baker act.�Pete Colantonio Dmitry Layevsky
Ryan Provencher Ryan Rafter hereby assign our copyright of this report and of the corresponding Executive Summary to the Mechanical, Industrial, and Manufacturing Engineering (MIME) Department of Northeastern University." We also hereby agree that the video of our Oral Presentations is the full property of the MIMEDepa rtment. Publication of this report does not constitute approval by Northeastern University, the MIME Department, or its faculty members of the findings or conclusions contained herein. It is published for the exchange and stimulation of ideas.
xi 1. Introduction
Trees offer a wide range of benefits to the environment, but when tree limbs fall and injure people or damage property, they become a concern. Forest trees grow quite well with only nature's pruning; however, landscape trees require a higher level of care to maintain safety and aesthetics. Taking care of tree hazards makes property safer and eliminates potential dangers that arise from planting trees where inadequate space was allotted for the tree to develop. Inappropriate spaces could be under power lines, next to homes, roads, sidewalks, driveways, parks and parking lots. Most utility companies have work crews dedicated to preventative maintenance to remove tree branches that are extending over power lines. These branches damage the power lines when they fall due to severe weather or their rotting. Aesthetic pruning is a concern of many homeowners who wish to enhance the appearance of their property. Tree pruning is also performed for the health of the tree. Common reasons for pruning are to remove dead branches, to remove crowded or rubbing branches, and to eliminate hazards. Trees may also be pruned to increase light and air penetration to the inside of the tree or to the landscape below. There are several conventional ways to resolve this concern. A homeowner could use any of the tree pruning products available on the market to trim the trees, or they could hire a professional landscaping crew to do the job. The introduction will describe the importance and background of tree pruning. The requirements of the design are described and followed by the need for the design. Alternative design concepts are then discussed because the waterjet-cutting device was infeasible. The elimination of the proof of the unfeasibility waterjet cutting design concept is then discussed.
1.1 The Need for a New Tree Pruning Device A new tree pruning device is desired for the following reasons: safety of the operator, functionality of the device and aesthetics of the tree. An extensive Internet search was performed for different types of tree pruning products that are available on the market. The details of this search will be discussed in the chapter 3 of the report. The goal was to benchmark available products. Various types of saw devices, manual and
1-1 powered were found, also a variety of shear type products such as manual loppers, ratcheting devices and hydraulic trimmers were found. Out of all the products that were found, none meet all of our requirements. This research is a very important part of the design process and it affects decisions that will be made regarding the pruning device. A landscaping crew on average charges $300 per tree for pruning. If the average household has three trees to prune twice a year, the cost incurred will be close to $1800. Not every homeowner would be able or would want to spend that much money every year on pruning trees. An inexpensive device that could reach higher and cut thicker branches than what is available would be the homeowners' best alternative to hiring expensive crews. The hydraulic driven shear tree-pruning device will eliminate the dangerous conditions that arise from working on a ladder. Most homeowners want the ability to do the work around the house. The homeowner will now be able to afford and purchase this device and perform the tree pruning on their property safely and easily. Our tree-pruning device will allow the operator to remain on the ground, avoiding the use of a ladder. It was our goal to also have the device lightweight, easy to operate and cost efficient so that an average homeowner could easily maintain the pruner.
1.2 Design Specifications The design specifications of this project are to
• Reach a tree limb that is 25-feet above the ground
• Cut through a 3-inch tree limb
• Prune trees in a safe manner
• Reasonable weight
• Operate easily and effectively
• Cost similar to comparable products available or contract services
• Deflect less then 6-inc:hes statically at the cutting end
1-2 1.3 Conceptual Designs of Cutting Mechanisms The initial conception for this design was a device that cuts through tree branches usmg a waterjet cutting device. Before the team could proceed with the conceptual design, the team needed to learn what water-jet technology was capable of doing. It was necessary to research several areas for information to assist in the decision making process. The team researched pure and abrasive waterjet technology, pressure intensifiers, and pressure washers. Initial calculations indicated that using waterjet technology is not feasible for this application. The results of these calculations revealed that using a power washer at 3500 psi as the pressure source would require 1 hour, 47 minuets to cut through a three-inch diameter branch. It was decided that the waterjet cutter does not satisfy the requirement of operating easily and effectively as stated in the design specifications in section 1.2. Several different technologies were considered for alternatives. The potential solutions were based on using standard shearing devices, manual or powered saws, and loping devices. Generally, it is not recommended to use chain saws for pruning trees, due to the type of cut you get. Safety is also an issue here since any inexperienced operator can easily get hurt by a chain saw as well as by any other powered tool. Manual saws and different types of loppers are relatively inexpensive and safe compared to various powered products. These devices require a good amount of physical effort that could get very tiring to use. The team's goal is to design a device which is safe, easy to use, and affordable. Of all the technologies that could be applied towards this design, some type of shearing device was the best possible alternative to a waterjet design. Shearing devices that are available on the market today are relatively inexpensive, safe, and easy to use. The only concern with those devices is that none of them can reach 25 feet high and cut through a three-inch diameter branch. Only one kind of lopper can cut three inches, but it is only three feet long, and this is not even close to the device requirements. A final decision was made on Tuesday, March 3, 1999 to eliminate the waterjet design concept from consideration. This decision required the team to proceed with the shearing device concept. The shear device will have to be hydraulic, pneumatic, or manual. A hydraulic device would require having pressures that range from 1500 to
1-3 3000 psi, and a pneumatic device requires pressures from 100 to 200 psi. Chapter 5 on the shear concept will discuss the importance of choosing the right type of piston.
1.4 Plan of Report Development This report is divided into eight chapters. Each chapter discusses a viable part to the design project, where the last chapter summarizes the work completed.
• Chapter 2 discusses safety and the importance of safety issues in relationship to the design. This chapter also discusses how the safety factors affect the design of the tree-pruning device.
• Chapter 3 "State-of-the-art" will discuss different types of tree pruning devices that are available on the market. These pruning devices include different types of saws, shearing devices, and loppe:rs. The chapter will also discuss the patents that were found related to existing products. Further it introduces waterjet and shear technologies and discusses the patents related to these topics.
• Chapter 4 "Waterjet Tree Pruning Device" introduces the initial concept for the pruning device. It thoroughly discusses the waterjet technology and how it could be applied to the design of a pruning device. This chapter also discusses the calculations that were performed to help us in making a decision to eliminate waterjet technology as a feasible concept.
• Chapter 5 "Shearing Device Concept" introduces shear cutting technology and how it can be used to design a new pruning device. It discusses the analytical analysis, physical testing performed, and conclusions made from these tests. Chapter 5 will also give a detail descriptionof the final design for the shearing device.
• Chapter 6 "Pole Design"' identifies the issues related to the pole design. It describes the mechanics of the initial concept and the relationship between material selection and pole dimensions. This chapter also discusses the analytical analysis of the telescoping pole, static and dynamic, the physical testing of the pole to determine the damping coefficient and the conclusions
1-4 that were made from these analyses. Chapter 6 will also give the detailed description of the design methodology and the final pole dimensions.
• Chapter 7 "Tripod Design" discusses the need and development of a supporting structure to accept the weight of the telescoping pole and shearing device. This chapter also discusses the analyses performed on the tripod configuration and a description of the fi nal design.
• Chapter 8 "Conclusion" summarizes the important issues that arose during the design process. This chapter will restate the design decisions, and give a brief description of how the device will be operated.
1-5 2. Safety
The activity of tree pruning is not a relatively safe practice. Tree pruners are at risk of falling from a ladder, cutting, electrocuting or overexerting themselves. The U.S. Consumer Product Safety Commission estimates that 133,000 injuries associated with lawn and garden tools were treated in U.S. hospital emergency rooms in 199 1. A major aspect of the design of our shear tree-pruning device is safety. Every aspect of the design will consider safety and comfort for the operator. This chapter will discuss, in a safety context, how and why to avoid the following
• Ladders
• Electrocution
• Rotating cutting mechanisms
• Overexertion
• Misuse of human factors Finally, the chapter will discuss the reasons for the addition of a tripod assembly to accept the weight of the telescoping pole and shearing device. 2.1 Non-Ladder Use The process of tree pruning often involves the cutting of limbs that are a high distance from the ground. Current devices are available that can reach 16.5 feet above the ground. Therefore, there is a need for a 9-ft ladder to reach 25 ft. The use of ladders is common for the operator to reach these limbs. There are many possible dangers associated with the use of a ladder. The first and most obvious is the risk of falling. A commercial ladder is rated to reach 6 to 8 feet, while an industrial ladder can reach from 8 to 10 feet. At a height of this magnitude, if the operator falls, they run the risks of badly hurting themselves. Figure 2.1 is a pictorial of the heights obtainable with current devices on the market. Additional problems of tree pruning with a ladder are that ladders must be repositioned for each tree limb that needs to be cut. The operator must climb down the ladder while holding the cutting device, and then reposition the ladder for the new limb to be cut. Often, the operator will climb back up the ladder to find that the ladder is not positioned properly and it must be repositioned.
2-1 25 Ft.
20-21 Ft.
14-16 Ft.
1 1-12 Ft.
5-6 Ft.
Average Person Person with Person with Person with Person standing on extension extension our tree with hand step ladder polesaw polesaw on pruning shearst ladder device
L------� Figure 2.1 Safe ty and height
The use of a ladder also puts the operator at risk by placing the operator at a location near the cut. Once the branch is cut, the limb will fall, possibly hitting the ladder or the operator. Another disadvantage of using a ladder to prune trees is that the operator has limited maneuverability. By being positioned on a ladder, the operator can only reach certain areas. In addition, if the operator overreaches or over extend their weight, they can loose their balance and fall. Therefore, an alternative tothe use of a 10-ft ladder is to use an extension pole capable of reaching the required height of 25 feet. If the design of this new tree-pruning device eliminates the use of a ladder, the operator can be safely positioned at a distance away from the falling branches.
2-2 2.2 A voiding Electrocution The design of this device must also take into account the possibility that the operator could be pruning near a high voltage power line. If this happens, the operator could then be shocked or even burned. The average power source coming into a home is two separate lines running at 110 volts each. It is necessary that the pole be designed for a worst case situation, which would be if the operator cuts through the protective casing of the power line. Therefore, a section of the assembly must be made of a material that is non-conductive separating the operator from the danger. Alternatively, a handle could be designed that will not allow electricity to travel to the operator. 2.3 Rotating Cutting Mechanisms The common cutting mechanism used for tree pruning is a saw. The saw is comprised of either a rotating or a reciprocating blade. These devices lend themselves to risks of the operators injuring themselves. The most widely known cutting mechanism, the chainsaw, has the capability of kicking back on the operator. In 1982, the Consumers Product Safety Commission estimated 24,000 medically attended injuries were the result of chain saw kickback. The rotation of the blade itself can cause unbalance and awkward forces that the operator has to compensate for. These unbalances can also produce excessive vibrations. Vibration is an area of concern that can cause injuries to the operator. These vibrations are transmitted from the rotating blade to the operator. Extended subjection to vibration leads to illnesses such as carpal tunnel syndrome and white finger syndrome. White finger syndrome occurs when operator uses a vibrating device for a long period in a cold climate. Devices that use mechanisms that do not use rotation, such as shears, are also possibly dangerous. Shears have the possibility of jamming midway through the cutting process rendering the blade unmovable. In this circumstance, the operator would be left to either pull the shears out of the limb or attempt to climb the tree to remove the jam directly. When the blade of the shear closes there is a twisting action, or torque due to the offset of the blades. This torque is then transferred to the operator, and if the torque is large enough, the operator could be injured due to the forces required to keep the device orientated correctly.
2-3 2.4 Injuries Associated with Overexertion The operator can also be injured if they are overexerted. Overexertion occurs in many areas such as manual cutting effort, over reaching, and holding the device itself. A manual extension saw requires a large amount of physical effort to cut through the tree limb. Add in the factor of the branch being 25 feet away, the operator must exert both manual effort and dexterity to accomplish this awkward task. The device should be lightweight, relative to the average homeowner's ability to hold an extended pole with a weight on the end for the time it takes to prune. If they have to hold a heavy object for extended time, there are possibilities that it would lead to back and arm strain. 2.5 Use of Ergonomic and Human Factors to A void Injury In addition to the device being lightweight, it should be easy to maneuver and adjust. The risk of injury is decreased by designing the system so that the operator holds the device close to their body at approximately the height of their waist. Figure 2.2 describes the optimal hand position for holding a heavy object. As can be seen, the preferred hand position for holding is between the elbow and knuckle at a height of 750 to 1100 mm. If the pole is well balanced the risks of injury, duringthe cutting application is minimized.
Ve ry Poor STANDING HT. 1700 ± 200 Ve ry Poor
SHOULDER HT. 1400 ± 1 fS O Poo• r ELBOW H T. "1100 :!: 1 50 Ve ry Poor Poo r
KNUCKLE HT. 750 ± 100 Poor KNEE HT. 450 ± 100 Ve r�v Poor
Figure 2.2: Optimal hand positions fo r holding
2-4 2.6 Use of a Tripod Assembly Once the weights of the cutting device and the telescoping pole were calculated, it could be determined that the force to carry, hold and maneuver the pole was too great for an average person. When the telescoping pole is extended to the full length and titled at an angle less then vertical, the forces that the operator must apply to keep the pole from tipping further are large. The operator would hold the telescoping pole to their side with their hands approximately 2.5 feet apart in a postulated grip. At only 15 degrees from vertical the operator would have to apply close to 40 lbs. of force with their forward most hand while supporting the over all weight of the assembly, 28 lbs., with their other hand. The magnitude of these forces is not acceptable for exerted periods. Another area of concern is if the operator allows the pole to titp past an angle in which they can comfortably hold. As the angle of pole tip from vertical increases, so does the moment about the base caused by the weight of the shears as well as the weight of the pole itself. This moment must be counter acted by the operator to avoid the pole from gaining dynamic momentum and tipping. For instance at an angle of 45 degrees, the operator must now apply over 80 lbs. of force while still holding the device. These forces are too high, and unpractical for safe use. A further area of concernwas the complexity of operation of the device. By having the shears hydraulically activated with a manual pump the operator must use a foot pump to cut through the tree limb because they have to use both hands to hold the telescoping pole. This design requires the operator to be ambidetrerous and is a challenging task. Therefore, a device was needed to accept the weight of the device and to allow the operator to maneuver it easily. The tripod assembly was designed to alleviate the weight of the pruning assembly and to be attached to the base of the telescoping pole.
2-5 2.7 Summary of Safety Concerns
All of the above stated concerns were applied to the design process of the tree pruning device. Chapter 4 on the Water Jet Tree Pruning Device will discuss in more detail the reasons why water jet technology was not a safe option for the design of the tree pruning device. Chapter 5 Shealing Design Concept will discuss in further detail the benefits of using a shear concept over a saw blade. Chapters 6 on the Tdpod Design will discuss the reasons that the use of a tlipod system will benefit the operator. The next chapter, Chapter 3 will discuss the devices found in the patent search and explain why they were not chosen in the final design concept of the tree pruning device.
2-6 3. State of the Art
Tree-pruning information and patent searches on pruning devices was compiled. This search involved the World Wide Web, U.S. government patents, libraries and various company catalogues. During this search, it was found that there are devices that would fulfill some of the requirements, but not all simultaneously. Therefore, this chapter discusses
• initial design concept of the use of a waterjet and the accessories needed
• alternativemechanical cutting mechanisms
• types of poles available
• availability of tripods on the market.
3.1 Introduction to Waterjet Technology Waterjet cutting technology emerged in the 1970's by a company called Ingersoll Rand. This technology can be used to cut virtually any material. The many advantages of waterjet technology have become very prominentin recent years. The advantages are
• clean cuts that require minimal or no secondary processing
• ability to cut without generating any thermal energy
• cutting does not deform the piece if used properly
• reduction of dust created. Typically, waterjets operate with a water pressure of 30,000 to 60,000psi that is achieved by using an intensifier pump. This flow isthen pushed out of a nozzle that has a diameter between 0.1 mm to 2.0 mm. This creates a velocity that can be three times the speed of sound.
3.1.1 Waterjet as a Tree Cutting Mechanism Since there are no existing patents for waterjet tree pruning devices, patent and information searches were done on the components of a waterjet cutting machines. Patents were found on intensifiers, mixing devices for abrasive waterjets, and various nozzles, see Appendix A.
3-1 3.1.2 Types of Available Intensifiers The intensifiers are used to increase the pressure of the water to ultra high pressures in order to create the supersonic flow of the water. Intensifiers use a reciprocating piston to "push" out the water at an ultra high pressure. A product search was done to find companies that deal with pressure intensifiers. Several companies were found, such as Marshalsea Hydraulics, that specialized in this area. These companies were emailed for specific information relative to our project. Figure 3.1 displays the internal mechanisms of the intensifier.
------·------�
FO Ftrstreverse stroke System (Jil ------·------� Figure 3.1 Internal mechanisms of an intensifier 3.1.3 Types of Available Nozzles The patent information on nozzles was for nozzles designed for quick assembly. These nozzles could easily be attached or detached to the assembly without the use of any tools. They also eliminated the step of aligning the nozzle to the assembly by making the attachment and the alignment one simple step. Information was found from a nozzle catalog of a company called Lechler, which deals with high-pressure nozzles and cutting nozzles. 3.1.4 Adding Abrasives to Waterjet Patents relating to mixing tubes used for abrasive waterjet were found. These patents describediff erent ways for the abrasives to mix into the water without cracking or eroding the mixing tubes or nozzle. 3-2 Some materials displayed in Table 3.1 cannot be cut by pure water and require the addition of abrasives. The abrasives combined with the high-speed water increase the rate of erosion in the work piece. When calculating the cutting rate and time to complete the cut, using abrasives, more factors must be considered • Cost of abrasives • Destruction of a nozzle • Abrasive collection The following table displays types of materials that can be cut by either using pure water or by adding abrasives into the water. Table 3.1 Abrasive vs. waterjet MA TERIAL (pure water) MA TERIAL (abrasive waterjet) Rubber Stainless Steel Gaskets Aluminum Foam Titanium Plastics (PU, PTFE) Stone, Marble Leather, Fabrics Glass Wood, Plywood GFK, CFK Food (Cakes, Fish) Cooper, Brass The abrasive waterjet milling machines that are used today can cost anywhere from $80,000 to $150,000; however, the components that were discussed above are available as individual components. Due to environmental and cost issues the benefits additives could provide, would not be effective for pruning trees. 3.1.5 Use of Pressure Washer to Obtain High Pressure 'Nater The pressure washer is a mechanical compressor that increases the pressure of a fluid. The fluid, which is usually water, enters the device at one pressure and exits at a much higher pressure. The pressures commonly associated with the pressure range from 1000 to 5000psi. These pressures are obtained by using the force of a piston to 'push' the water out of the device. A motor, which may be either an internal combustion or electric, 3-3 turns a iveshafdr t that in tum reciprocates the piston in a back and forth manner. Check valves provide that the high-pressure water will only travel in an outward direction as the piston moves. Figure 3.2 displays the concept of a pressure washer consisting of a pump and intensifier. Ultra-High Pressure Water to Cutting or Cleaning Component ELECTRONIC PL- C CONTROLS / Figure 3.2 How a pressure washer works The exiting pressure from the device is a function of the motor horsepower. A pressure of lOOOpsi may be developed by a motor of 3.5hp, while 4000psi require a motor of 15hp. When the motor becomes this powerful, its size and weight make it difficult to move. Power washers of this magnitude are usually attached to a cart with rolling wheels for the operator to move about. As indicated in the waterjet section, the pressure required to cut through wood can be as high as 30,000psi. With the addition of a pressure intensifier, these high pressures may be reachable as described earlier. Otherwise, the use of a pressure washer would not meet the needs of waterjet cutting. See Appendix B-1 for pressure washer comparisons. 3.1.6 Conclusion of Waterjet Technology In conclusion, the waterjet tree-pruning device is a totally original concept. The team must take what we now know from current waterjet technology and attempt to integrate this technology into the tree pruning device. Whether or not this concept can be 3-4 realistically designed or afforded is something that will be discussed in chapter 4. It was necessary to pursue design concept alternatives, since the unfeasibility of using waterjet technology had not yet been determined 3.2 Mechanical Cutting Mechanisms The two basic types of cutters used in pruning today are the anvil and by-pass cutters. Anvil cutters typically have a flat blade that cuts against a solid surface called the anvil. The cutting force is symmetrical which prevents twisting and is more efficient than the by-pass cutter. Anvil cutters are recommended tor use on deadwood branches since bruising may occur on green plants. Figure 3.3 displays both anvil and by-pass cutting mecha · sms ;:.:.m:.: .:.:.:.::..:.·------ (Anvil cutter) (By-pass cutter) Figure 3.3 Cutting stylesfo r shear devices By-pass cutters usually use a curved blade that slides past a hook, which is also curved with a flatfa ce. Due to the offset blade, the cutting force induces twisting on the handle or other blade interface to the user. The hook must be placed on the side of the branch to be discarded so that the bark of green branches is not damaged. This is the prefened cutter for use on green branches since the cut is cleaner than the anvil cutter. The common manual shearing tool has the blades mounted to levers that pivot about a single point. Longer handles are used to increase the cutting force for larger diameter branches. Improvements of the simple pivot have been made that use additional levers or a gear driven system to provide a higher mechanical advantage. Some anvil cutters have been produced that incorporate a mechanical linkage where the blade slides relative to the anvil during the cut. Figure 3.4 displays examples of mechanical advantages. 3-5 (Gear drive variant) (Additional lever feature) Figure 3.4 - Various shear devices used to increase mechanical advantage Pole pruners that use loppers at the end of an extension or telescopic pole are often powered by a lever/pulley system with a rope the operator pulls from the ground. Figure 3.5 illustrates the lever/pulley system. Figure 3.5 - Rope lever diagram A hydraulic manual pole pruner uses a hand-operated piston with a larger piston to actuate the shears to increase the cutting force. Powered hydraulic and pneumatic hand and pole pruners are produced for commercial use where fatigue and large branch diameters are a concern. Powered pole pruners use a pump or compressor to actuate a piston to provide cutting power to the shears through a mechanical linkage. Most pumps or compressors are powered by a small gas-engine for portability. Some manufacturers 3-6 even have the compressor mounted on a backpack that allows the operator to move around freely. Hydraulic fluid designs operate at about 1500-3000psi, while pneumatic systems operate at about 100-300psi. Figures 3.6 and 3.7 display hand operated and gas Figure 3.6 Figure 3.7 Hand-operated hydraulic pruner Gas-powered hydraulic pole pruner A specialty company, Razor-Back, produces a ratcheting tree pruner that features a 12-foot telescoping fiberglass pole that allows you to easily adjust the length to reach limbs that need pruning. See Figure 3.8 for an illustration of the device offered by Razor Back. The lopping blade can easily cut branches up to 1.5 inches in diameter. A nylon rope with a wooden handle is used to advance the ratcheting blade one step at a time with a minimum amount of effort. For larger branches the pruner has, a 14-inch hard chrome saw blade. The blade is slightly curved to allow it to smoothly slice through the wood during the cut. The suggested retail price for the ratcheting pole pruner is $49.95. 3-7 Figure 3.8 Ratcheting tree pruner by Razor-Back Several other companies such as Fred Marvin Associates and Corona Clipper produce a very similar type of saw-pruner. The products perform the same task and look very much alike. The only difference between them is the length of the extension pole and price. The extension pole is made of fiberglass and can be manually extended from 6 to 14 feet maximum. The price for these types of pruners ranges from $50 to $120. Figure 3.9 illustrates the ratcheting pruner from Corona Clipper. Figure 3.9 Tree pruning system by Corona Clipper A pole saw is a very simple device that features a simple curved saw attached to a fiberglass extension pole. The device is simple to use and safe but it is only available with poles that extend to 14 feet maximum. It could be purchased for less than fifty dollars. Of all the pole pruning devices found during the information search, none were longer than 13 feet and the maximum cutting diameter was 2.25 inches. There was one hand-operated model that could cut 3-inch diameter branches, but was only 3 feet long. 3-8 In summary, a pole pruner that can cut 3-inch diameter branches 25 feet in height to meet our design requirements is not commercially available. See Appendix B-2 for comparisons of available shears. Since the cutting capability of the shearing device was undetermined as of yet, additional devices were found. 3.3 Saws and Loppers Available on the Market There are different kinds of saws available on the market, which vary by size, price, difficulty to use, and purpose. For example, a chainsaw is mainly designed to cut large wooden objects such as trees and large limbs. Due to high weight and safety reasons, chainsaws are designed to be used while standing on the ground. The simple manual saw is designed mainly to cut wooden objects of a smaller size such as tree branches. The manual saw is safe and doesn't require any special skills to operate. The only major problem with saws is that most of them cannot be used to reach branches that are more than ten feet from the ground. All the mentioned products are affordable, safe , and require no special skills to operate for the average homeowner. The only issue is that they cannot reach branches that are 25 feet from the ground and the operator needs to put a lot of effort to cut through a 3-inch diameter branch. Only two companies were found on the Internet, which have pruning devices that are very similar to our needs. Husqvarna Corp. designed an extension pole saw that features an extension pole that could be extended from six to twenty feet. A 14-inch chain saw is attached at the end of the extension pole, and is driven by 49cc 2.4hp engine with a maximum of 11,000 RPM. The weight of the system excluding the motor and the shaft is 17.6 lbs. The combined weight of the shaft, motor and the cutting mechanism will exceed the teams requirement for weight. The price for this device is not readily available. One of the major advantages of this system is that it is a backpack unit and it transfers most of the weight to the operator's hips to reduce arm strain. Figure 3.10 is an illustration of the pole chain saw offered by Husqvama. 3-9 Figure 3.10 250PS hydraulic pole chain saw by Husqvama Kensma markets a similar pruning device, which is called the Power Pruner. This device features an extension pole and a saw that has 12-inch sprocket nose chain bars and a 3/8-inch pitch cutting chains that can effortlessly cut through 12-inch limbs .. Although the telescoping and extended shafts allows the operator to remain on the ground and a safe distance from falling branches. The Power Pruner and the Extension Pole Saw are not ideal systems for landscapers, tree services, and homeowners because of the safety concernwhen using chain saws. Two patents were found related to the chain saw design (See Appendix E). One of the patents (#5,269,064) describes a safety guard feature for protecting against accidental contact, with the longitudinal side edges of a chain saw cutter bar. The second one (#5,669,145) is on chain saw attachment that provides a pivot point for better leverage and control especially when cutting small tree branches or limbs. 3.4 Summary of Existing Products After benchmarking the competition, there is no current technology, that uses either waterjet cutting technology or any other form of cutting devices, that meets all of our requirements. Safely cutting a three-inch diameter tree limb that is twenty-five feet above the ground would be a state-of-the-art design. The design of this device will include an extension pole to reach a height of twenty-five feet. 3-10 3.5 Existing Poles on the Market The poles discovered in the search included poles of the following type • solid non-segmented • extendable with sectional attachments • telescopic poles all with varying lengths The poles found were made of different materials depending on the use or function. The poles also varied in the cross sectional area. From the collection of poles found (See Appendix A-4), companies with poles similar properties such as length and non-conductive material were kept. The following sections describe the poles that came closest to satisfy the design specifications. 3.5.1 Testrite Instrument Company The Testrite Instrument Company had both telescoping and extension poles. Testrite claims that their poles are lightweight, strong, ergonomic, and multi-functional. The available length of their poles has not yet been determined. The impressive feature for the Testrite's poles was the variety of locking devices. Figure 3.11 illustrates three examples of the locking styles, which Testrite uses to hold the pole sections in place: Style A Style B Style C Figure 3.11 Three styles of Testrite locking devices Each of these requires manual force to lock down the different sections. Each section can be extended at the base of the pole. Style A and C use the rotation of the pole sleeve to lock down the extended section. Style B makes use of an external knob, which screws into the pole to hold it in place. The function of these poles would be dependent on the weight applied at the end. The locking of one section of the pole to another section can be done in several ways as indicated in chapter two, the State-of-the-Art. 3-11 There are two categories of locking devices, internal and external. Both types would require manual force applied to a mechanical device to lock the different sections. Each section of the pole could extend at the base of the pole with the locking device located at the top of each shell pole. The externaldevices for locking the sections usually consist of a screw action or twisting action of a separate piece of material on the pole. The mechanics of the screw action device can be best illustrated with figure 3-12. This figure shows how external knobs will be placed at the top of the base pole and each of the proceeding poles. A clockwise motion will tighten the top section of the device to the smaller pole section and the lower locking section will hold its place on the base pole section. A variation of this can have a pin that will create pressure on the internal pole section. The pin is screwed into place and causes telescoping section to lock into place. This type of lock is open for slipping, and damages the internal poles exterior. The second style of external locking devices is the twist action of a separate part on the pole. This style can best be described as a collet that is fixed to the end of the base pole and when twisted tightens the internal diameter (ID) of the base pole to lock onto the OD of the extending pole. The external collet is easier for right and left-hand operation. The external knob device is difficult for opposing hand operation. A left handed operator needs to adjust the height, if the pruning device, and locking device, is orientated on the right side they would be forced to change the orientation of the pruning device to adjust the height of the pole. With the use of an external collet, the operator would be able to avoid these situations, whether the operator is left or right handed. (Testrite External LockingDevice) Figure 3-12 external locking device 3-12 Figures 3-13 illustrates the external collet device on a three-section telescoping pole system. (Mr. Long Arm, Inc.- model ProLok 2300) ·------Figure 3-13 /llustration of external collet locking devices As seen in Figure 3-13, the first noticeable difference is the lack of a knob. The lack of the external knob reduces any interference they may have with the surrounding environment. If the pole were to be extended into a dense section of the tree, the external knobs could easily be caught up on branches while trying to reach the desired location to prune. The internal locking devices can be composed of internal snaps, which would lock into holes at various lengths along the base pole, or by having the entire pole twist into a locked position. Both of the internal locking systems have faults. The snapping system requires that a hole be milled into every area of the base pole that the extension pole would be capable of extending. The second method of twisting the poles into a locked position requires that the entire pole be twisted into the locked position. The twisting motion affects the orientation of tree pruning device in relation to the tree branch. The locking system that will be used in the design of this pole is the external collet. The collet provides increase functionality to the use of the pole. 3.5.2 Trailblazer Products The Xtend-A-poles from Trailblazer Products can reach lengths of sixteen feet. An Email was sent to Trailblazer asking about potentially making a twenty-five foot pole for this project, but their reply was they could not, without any further explanation. Although the Trailblazer pole does not meet our requirements, the function of the pole is desirable. Their poles are made of fiberglass, which is a non-conductive material. Figure 3.14 is an illustration of the style of pole that they produce. Figure 3.14 - Xtend-A-Pole fr om Trailblazer products 3-13 3.5.3 Treasure Valley Supply, Inc. (TVS) TVS makes external locking telescoping extension poles, called STECCONE. As the Testrite poles the length of the TVS poles are varied. The range of the TVS poles can reach is four to twenty-four feet. They are easily extended and secure into place. The TVS poles are made of high tensile strength alloy that has been anodized to resist corrosion. The TVS poles qualify under the height requirements, but would not be able to with stand the load of the shear pmning device. The illustration Figure 3.15 shows the metallic pole from TVS in it's collapsed state. Figure 3.15 Illustration of TVS aluminum pole In order to use this pole it would require an insulated covering for the pole to prevent the conduction from a power line. 3.5.4 Mr. Long Arm, Inc. The last company that has acceptable poles is Mr. Long Arm, Inc. This company sells numerous types of poles and for many uses. They specialize in cleaning extension poles as well as professional extension poles. On their web page, two poles, the ProLok and Alumiglass, had a reach of twenty-three and twenty-three and a quarter feet. The ProLok model series 2200/2300, heavy-duty pole (Figure 3.16) is made of composite fiberglass fluted handle for easy grilp. The extension pole is die cast aluminum with a chuck and collet-locking device. Both the 2200 and 2300 poles could be very useful, however, the aluminum material will not meet the non-conductivity requirements. The three-sectioned pole has an advantage over the two-sectioned pole. The operator can effectively change the height of the pole, without changing their body position. 3- 14 (Two sectioned ProLok 2200) (Three sectioned ProLok 2300) Figure 3.16 Illustrations of Mr. Long Ann poles The other pole from Mr. Long Arm is the Alumiglass model series 6500/6600 multi-purpose pole. It has the same technology of the ProLok, but has the ability to extend three inches longer. Both poles come with the option of two or three sections. Figure 2.7 illustrates the Alumiglass poles from Mr. Long Arm. (Two sectioned Alumiglass 6500) (Three sectioned Alumiglass 6600) -"'----- Figure 3.17 Additional illustrations of Mr. Long Ann poles Since the pole requirements states that the pole is made of a non-conductive material, the Mr. Long Armpole would require an isolation cover. The cover would need to enclose the entire pole to avoid electrocution to the operator. Although none of the poles found fulfilled both important requirements of twenty-five feet reach and made of a non-conducting material, all of the existing poles could lbemodeled. 3.6 Basic Poles The first and most common type of pole is the basic pole found in a broom or mop handle. This type of pole can be made of wood, aluminum, or any other material that is practical for the pole's application. The biggest disadvantage of this basic type of pole is it has a limited range. One of the requirements for the design of the pruner is that it is marketable. A basic pole has a finite length, which reduces its ability to be safely used for cutting branches at various heights. If you manufacture the basic pole to a length of 5ft,it can only safely reach a range of 5ft. In order to reach heights beyond the 3-15 length of the basic pole, a ladder must be used and as stated in the chapter 2, the use of ladders is unsafe. 3.7 Segmented Extension Poles The second type of pole that exists on the market today is the segmented extension pole. The segmented extension pole is a system of poles composed of the basic pole, with two or more pole segment connections. These segmented poles connect in two ways. This can be done by either snapping one into another or by screwing one into the other. Segmented extension pole systems can be designed so that each section is equal in length to that of the additional segments. The segmented poles can also be designed so each of the additional segments is smaller in length and diameter. Because their lengths are adjustable, segmented extension pole systems are better than the basic, thus increasing the range for performing a function. The disadvantage of the segmented extension pole is the limitations of the lengths. An example of this limitation is the consumer who buys a segmented pole system composed of three pole segments, each segment having a length of 5ft. As the consumer is performing this function, they need to reach a length of 12ft. The consumer then connects two of the three sections together. The pole system is now 2ft short of the required length of operation. The operator either must use a ladder to reach the extra 2ft or over extend their body to finish the task, both of which are dangerous. The other option for the operator is to attach the third pole segment for a total length of 15ft. Now the operator has an additional 3ft of pole, but will be required to choke up on the pole in order to reach the desired location. The extra 3 feet of poh� behind the operator can hit a fence or a building, which can interfere with the performance of the function. The segmented extension pole system is a good tool for some applications but is not the practical solution for this tree-pruning device. Both the basic and segmented pole can either be a solid or hollow cylinder; the hollow cylindriical pole would be lighter in weight. The importance of weight will be further explained later in this chapter. 3-16 3.8 Telescoping Poles The last typical pole type on the market today is the telescoping extension pole. The telescoping extension pole is a system of interlocking poles with a shell pole that encloses all the additional poles. The shell pole is the base pole segment and has the biggest diameter. Each extending pole is enclosed in the previous pole. Therefore, the proceeding segment length is smaller in diameter than the previous one. They can also be the same lengths as the base shell pole or decrease in length as they extend. The benefit of the telescoping extension pole is its ability to adjust to any height within its overall range. A telescoping extension pole that is designed to reach a height of 25ft can also be extended from 5ft, the length of the base shell pole, to the maximum design length of 25ft. The telescoping extension pole system is composed of hollowed cylinder for a lightweight device, and can be made from any desired material. 3.9 Tripods Consumer search of the tripods currently on the market revealed that the tripod would need to be design by the team to function in specific manner for the device. The team benched market current tripods in order to design the tripod used for the shearing assembly. Chapter 7 "Tripod Assembly" will furtherdiscuss the tripodin more detail. 3.10 Results of Findings From the information gained in the state-of-the-art, it was concluded that there was no device or devices available on the market to purchase and assemble that would meet the needs of the project. None of the poles found in the search met the reach requirements. There was no current technology for the use of a waterjet device for pruning trees. That none of the shearing devices found could cut through a 3 inch diameter branch at a height of 25 feet above the ground. The design of this tree-pruning device would be an original design, in that all the components, except for the shearing blades, would have to be design by the team. The following chapters discuss the design methodology and decisions made for the various components of the tree-pruning device. 3-17 4. Waterjet Tree Pruning Device The initial specification of this design was to use a waterjet cutting device to prune trees. Since then, an in-depth analysis and several other factors have concluded in the elimination of this device as a feasible solution. This chapter will describe why a waterjet cutting device is not effective, efficient, or feasible as a device to prune trees. 4.1 Waterjet Cutting Technology Waterjet cutting technology is widely used in the industry today to cut virtually any material. Figures 4-1, 4-2, and 4-3 shows several waterjets cutting through various materials. The waterjet system is setup on a table similar to that of a milling machine. The waterjet uses pressure intensifiers to generate a pressure in the range of 35,000 psi to 60,000 psi. Figure 4-1 Waterjet Figure 4-2 Waterjet Figure 4-3 Waterjet cutting through rope cutting through marble cutting through stainless steel There are several advantages to using waterjet cutting technology. The waterjet leaves the material with an excellent surface finish, thereby eliminating the need for secondary processes such as filing or deburring. The waterjet provides a very accurate cut allowing for intricate cuts and saving on wasted material. Waterjet cutting decreases the amount of stress on the material eliminating crack formation in brittle materials. Last, 4-l the waterjet does not generate any heat while performing the cut, which could lead to imperfections in the cut. Figure 4-4 illustrates a 2D-table setup with eight waterjet cutting heads. Figure 4-4 2D cutting table with 8 waterjet cutting heads To use waterjet cutting technology as the cutting mechanism for this design concept, the mechanics of waterjet cutting and the mechanical properties of wood must be well understood. Section 4.2will describe in detail the mechanisms of waterjet cutting and emphasize the importance of understanding the material properties of wood. 4.2 Mechanisms of Cutting Wood with Waterjet Technology Waterjets use pressure intensifiers to increase the pressure from 35,000 to 60,000 psi. The inlet water usually has a pressure of 80 to 100 psi, thus the pressure intensifiers can increase the pressure over ten times the inlet pressure. A 250 HP motor is generally used to power waterjets of this magnitude. After the water has traveled through the pressure intensifier and the pressure of the water has been raised, the water is then forced through a nozzle. The nozzles used for waterjet cutting tend to have orifice diameters ranging from 0.1 mrn to 2.0 mrn . Some cutting nozzles have orifices that are made out of sapphires or diamonds. These orifices 4-2 tend to last longer and withstand more wearing than an 01ifice made of a metal, such as steel. The water forced out of the nozzle forms a fine compact spray that has a supersonic velocity. The material must be relatively close to the nozzle so that the water does not lose its kinetic energy and disintegrate. As the water impacts the material, it causes the material to be compressed in the area of impact (See Figure 4-5). The material then fails in the area of compression. The compressive strength of the material is overcome by the constant impact of the waterjet stream thus allowing the material to be cut. The compressive strength of the wood in this application is equivalent to the tensile strength of the wood. Figure 4-5: Material erosion The unique properties of wood do not allow a direct correlation to the mechanism of waterjet cutting. Wood is unlike any other material in that it is an orthotropic material. Its material properties are unique and different in three different directions. These directions are longitudinal, radial, and tangential to the grain direction. Looking at a tree branch, the grains will run along the branch from the base of the tree to the end of the branch. Since the waterjet cuts across the grains in this application, the tensile strength must be perpendicular to the grain (See Figure 4-6). The tensile strength of wood perpendicular to lthe grain, which is about 25 MPa for the strongest wood, is an average of the tangential and radial components. The tensile strength of 4-3 wood parallel to the grain is 110 MPa for the strongest wood (See Appendix C-1). Now that the mechanics of cutting wood with waterjet technology is understood, calculations must be done to determine the feasibility of this design concept. Figure 4.6 Waterjet cutting tree branch 4.3 Initial Waterjet Design Concepts After brainstorming, a decision was made on the best way to power the waterjet cutting device. Considering that this product will be sold to either a homeowner or a professional, it is not feasible to use a standard pressure washer to power a pressure intensifier. It was then decided that the best way to power the waterjet design would be to use a pressure washer. The research on pressure washers, revealed that the most easily obtainable and affordable pressure washer for a homeowner can be obtained either by purchasing from a store such as Sears or rented from any rental agency dealing with power tools. The pressure washers we will consider have a flow rate of four GPM with a pressure of 3500 psi. The next step in the waterjet design concept is to decide on what type of nozzle is needed for this application. Information was received from several companies specializing in nozzles (See Appendix B-3). This information shows that a nozzle rated for a flow rate of four GPM and a pressure of 3500 psi must have an orifice diameter of 4-4 either 1 or 1.1 mm. In addition, it was recommended from several vendors that the nozzle have a 1/4 NPT rather than a 1/8 NPT for connection to the pressure washer because of the relatively low pressure. Generally, the industry uses 1/8 NPT nozzles for high pressure applications and 14 NPT for low-pressure applications. A concept was visualized using two nozzles, after considering the high pressures and velocities needed for waterjet cutting. This concept would increase the cutting rate of the device therefore decreasing the total time needed to cut through a three-inch diameter branch. Figure 4-7 is the initial design concept of a dual nozzle device. Several considerations were included while brainstorming about this device. These considerations make the dual nozzle concept work safely and more effectively than a single nozzle device. The first consideration was having the nozzles angle inward at rest position about one inch apart. When the nozzles are opened fully to cut the three-inch diameter branch, they will be approaching the vertical axis to allow for a full cut. The nozzles never reach the vertical axis because the nozzles should never be pointed at each other. If they were not angled initially, they would be angled outward as they opened thus missing some of the cut. Figure 4-7 Dual nozzle design concept The next consideration taken was to have the two nozzles spring loaded. This would stop the nozzles from flying open when the high-pressure water is turned on. A 4-5 vertical pin will also stop the nozzles from opening past the three-inch diameter cutting range. There would also be a safety shut-off device. This would shut off the flow of water when the nozzles were sitting in rest position. If the nozzles were opened too far, past the maximum cutting range, the water would also shut off. Calculations were also done to find if the velocity and pressure created by the pressure washer are high enough to cut a tree branch. In addition, the cutting rate for the dual nozzle concept was fo und in order to determine if the time to cut through a three inch tree branch is feasible. 4.4 Waterjet Calculations The pressures and velocities of current waterjet cutting devices are extremely high. Calculations must be done to verify the feasibility of using a typical pressure washer to power the waterjet cutting device. The pressure washer will have a flow of four GPM and a pressure of 3500 psi. See Appendix D-1 for full calculations. To calculate the velocity of the water as it is exiting the nozzle. The velocity of the water before the nozzle orifice must be calculated using the flow rate of the pressure washer and the cross-section area of the pressure washer hose. V1 = � (4-1) The Reynolds Number can now be calculated. The Reynolds Number is needed for a correlation to find the discharge coefficient. Once the discharge coefficient has been found, the velocity exiting the nozzle can be calculated. Note that 13 is the orifice diameter ratio, douJetfdinlet· (4-2) Now that the exit nozzle velocity is calculated, the pressure force that this velocity applies to the branch is calculated. Pf = p *Q*V2 (4-3) An analysis was done in excel (See Appendix D-2) to calculate these velocities and pressure forces. This was done while varying the orifice diameters and pressures 4-6 from the pressure washers. This gives a range of velocities and illustrates how the velocity is affected when the orifice diameter and pressure changes. Taking the pressure force calculated from equation 4-3, the strength (o") can be calculated by dividing by the area of impact. This can be related to the cutting force as shown in equation 4-4. 1 Pz �2· C�oJ (4-4) This cutting force is calculated twice (See appendix D-3) using the strength calculated from the pressure force and the tensile strength of wood as described in section 4.2. These two calculations are then compared. The cutting force due to the pressure force significantly overcomes the ltensile strength of wood. This confirms that the pressure washer will provide enough force to cause the material to fail in the area of impact. However, this does not say that it will be able to cut through the three-inch diameter branch. Calculating the cutting speed of this device and the time that it will take to cut through a three-inch diameter branch is the next step in this analysis. To calculate the cutting rate of our design concept, equation 4-5 from High Pressure Jetcutting by Tikhomirov will be used 24 -.75 _ . 4 5 at (4-5) S =7./ _1?_ (dnt' 3 (htl.3 _ �l lOO ) ( 100 ) where p (MPa) is the pressure from the pressure washer, dn (mm) is the orifice diameter of the nozzle, h (mm) is the depth of cut, and at (MPa) is the tensile strength of the wood. The issue of concernnow is the depth of cut. The depth of cut is not constant because the waterjet will be moved across the tree branch. The branch must be modeled as a semi-circle and divided into slices (See figure 4-8). The cutting rate, S (mmls), must be calculated for all the slices in the model because the depth of cut will be different at each slice. Once the cutting rate is calculated for each slice, the time to cut each sllice is calculated by dividing the depth of cut by the cutting rate, S. The time to cut each slice is then added to find the total time to cut through a three-inch branch (See Appendix D-4). 4-7 Figure 4-8 Integration of tree branchfo r cutting speeds 4.5 Conclusion of Waterjet Calculations Seventy-five slices were used with depths ranging from 1 mm to 38 mm (1.5 inches) and then back down to 1mm. The total time to cut through the three-inch branch was found to be approximately 1 hour and 45 minutes. This is not an acceptable time to cut through a three-inch branch. The next step taken was to vary the pressure from 3500 psi to 35,000 psi and find the time to cut through a three-inch branch for each pressure, Figure 4-9 illustrates the significant increase in pressure to reduce cutting time. 300 250 200 150 "'., E a. 100 � 50 - -- � - 0 0 1000 2000 3000 4000 5000 6000 7000 Time fo r Cut (sec) Figure 4-9 Pressure vs. cut time 4-8 4.6 Industry Concerns Since initial brainstorming began, several contacts were made via email about the concept of cutting a three-inch tree branch with a waterjet powered by a pressure washer. The contacts made were engineers that either worked for companies that specialized in waterjet cutting or were members of the Waterjet Technology Associations (WJT A). The WJTA is an organization dedicated to the education of waterjet technology. The responses that were obtained were not very positive (See Appendix F). A common statement made by all of the contacts was that cutting a three-inch diameter tree branch with a waterjet powered by a typical pressure washer would not be effective or efficient. One point made from George Savanick, member of WJTA, is that the waterjet needs to be able to continuously pass through the same cut line. This means that the nozzles must be fixed onto the branch so the nozzles can pass over the same cut line. The idea of using a pressure intensifier was considered during brainstorming. U a pressure intensifier was used, the inlet pressure from the pressure washer could be raised on the order of ten times the inlet pressure. The problem, as stated earlier, is that pressure intensifiers are extremely expensive and tend to very large. This would eliminate the portability as well as the cost effectiveness of the device. 4.7 Elimination of Waterjet Cutting Device This chapter described the information obtained and analysis done that verifies the fact that the waterjet cutting device is not a feasible solutions to the design problem. Several major factors render the waterjet device unusable. One factor is the time to cut through a three-inch branch with a typical pressure is not feasible. The only way to lower this time factor to make it feasible is to increase the pressure by means of a pressure intensifier. The pressure intensifier is very large and expensive and raises questions of safety. Does the operator really want to prune trees while standing next to an intensifier that is generating pressures of over 30,000 psi? Adding abrasive materials into the waterjet was considered for this device. The benefit of adding abrasive materials is a higher material removal rate that would decrease the time to cut through the three-inch branch. 4-9 However, the disadvantages heavily outweigh the advantages of using abrasive materials. Other factors must be considered such as catching the abrasive materials so they do not damage the tree or the grass. The nozzle would erode much faster using abrasive materials. The mixing tube for the abrasive materials would have to be designed or purchased which would be very expensive. The mixing tube would have to be very close to the nozzle, thus causing a problem of fitting or jamming in the tree. Aside from these disadvantages, the abrasive materials would not help the waterjet design concept. The pressure would still have to be above 30,000 psi to be effective. In addition, the problem of re-entering the cut line, which is described below, is still a major factor. The other factor is being able to re-enter the cut line with the waterjet stream (See Figure 4-6). The waterjet would not be able to make the cut through the tree branch in one pass because of the small cutting speeds and long cut times. Therefore, the nozzle would have to make several passes to make the cut. If the nozzle does not re-enter the cut line, then each pass the nozzle makes will be starting the cut over again. Keeping in mind that the orifice diameter is one millimeter, this task is virtually impossible to accomplish twenty-five feet above the ground on a telescoping pole. The only possible solution to keeping the waterjet stream in the same cut line would be to clamp onto the tree branch. This solution is not desired because it raises other undesired factors. This clamping action would damage the tree branch during the cut. In addition, if the desired cut is close to the tree trunk then the clamp would be useless because of lack of room to clamp the device to the branch. These factors provide strong evidence that the waterjet cutting device is not a feasible device. The device would not be feasible if it was powered with a typical pressure washer because of the time required to cut the tree branch. If the time to cut was decreased using a pressure intensifier, the device then would affordable for the homeowner or the landscaper. The siizeof this device would be extremely large eliminating the factor of portability. Therefore, the alternativecutting method of shearing was investigated. Chapter 5 Shearing Design Concept will discuss the design decisions made and the concernswith the design of the tree-pruning shear device. 4-10 5. Shearing Device Concept This chapter entails the shearing device concept and its related components. Concept definition and concerns are stated with design methodology including analytical and physical testing procedures. 5.1 Design Concepts Designing the means to power the bypass shear blades was the first task the group handled. Initially, the group was looking into a pneumatic piston to power the shears. Several considerations eliminated this from being a design concept. The general weight and size of pneumatic pistons are greater than that of hydraulic pistons capable of generating equal or greater force. In addition, an air compressor would be needed to power the piston. This is not a device that an average homeowner would have. It is also much more expensive than a hydraulic hand pump. This leads us into our final design concept that has a hydraulic piston and a hand pump that is cheaper than an average air compressor. 5.1-1 Final Design Concept The recommended concept features a symrnetiic:al design to eliminate any moments from being transferred from the shear assembly to the extension pole (See Figure 5-1). The prototype is designed around the Corona ® WL6490 bypass shear that was removed from their 3-foot hickory handles for use in the design. See appendix F for drawings of the assembly and all of the components. Preliminary field observations of manual force requirements with the Corona ® shears as purchased were made cutting various branches at random. Three-inch diameter softwoods such as live pine could be cut with some difficulty. However, no one in the design group was capable of cutting dead or semi-green hardwood over two inches in diameter. Based on the assumption that we were of "average" human ability, all manually powered designs using levers or gears were determined to be impractical, and thus eliminated from consideration. 5-l Figure 5-1 Final Design After force requirements were established through physical testing, the design of the device could be finalized. The assembly is partially enclosed inside of a square aluminum sleeve (See Figure 5-3). The bypass blades are pinned through two brackets with a custom designed nut and bolt (See Figure 5-2). The blade arms are then press fit and screwed into two extension arms. These extension arms are then pinned to two working arms, which are in turnpinned to the rod clevis of the hydraulic piston. 5-2 Figure 5-2 Shear Blades with Custom Nut and Bolt A 3000-psi hydraulic hand pump is connected in a closed circuit loop to minimize the probability of foreign particles entering the system. A double acting hydraulic cylinder with a 2-inch diameter bore and 5/8" diameter piston rod is coupled to the hand pump to power the shearing device. The maximum pressure rating of the cylinder is 1300 psi, and weighs about 10 pounds. All of the hydraulic components are commercially purchased and are NFPA or SAEpressure certified. To return the shears to their initial position after the cut, the opposing end of the double acting cylinder is sealed. The trapped air compresses and acts as a spring to force the fluid back into the reservoir once the release valve on the pump is opened. To prune low-level branches with ease, the square sleeve that encloses the piston can be detached from the extension pole by removing a spring-loaded quick release pin. 5.1-2 Sleeve Design Methodology The blue sleeve displayed in Figure 5-l and Figure 5-3 is intended to be independent of the main extension pole. The methodology of using a separate member was to design the sleeve to withstand the compressive forces transmitted between the piston and cutter hinge pins. This approach eliminates extensive modifications to a 5-3 purchased extension pole and simplifies the pole design by facilitating parallel analysis with the shearing assembly. Figure 5-3 Square Sleeve 5.2 Concerns Many design concernsexist for the development of the shearing assembly. These concernsinclude • Jamming • Overall weight • Cutting torque • Effective cutting diameter 5.2-1 Jamming Jamming of the shears while cutting is a concem of the design group. Generally, single blade designs such as our concept are less prone to jamming verses double blade designs. The potential for jamming increases if the operator attempts to cut through a knot in the branch. Figure 5-4 indicates knot locations at the extreme base and intersections of all branches. 5-4 Base knot locations Figure 5-4 Knot locations Branches that have been pruned or rotted off the area of the limb to be cut are additional sources of knots. The knot formed at the base of the limb to be cut in not a concern since it is beyond the typical cutting area. The initial solution was to use a reversible piston to release a jammed blade. The additional pressure line required for a reversible piston adversely effects the overall design in these areas • increased weight of second hose • routing and entanglement concerns • cost and complexity of required components Reversing the piston does not guarantee a jammed blade will be removed from the limb. The opposing blade and entire pole could shift while the jammed blade remains sufficiently embedded in the branch. The counter effects of using a reversible piston were determined to be more significant, and the concept was not selected. The probability of jamming can be reduced by significantly increasing the amount of force generated by the piston. It is anticipated that knots and general jamming problems will not occur frequently. The effects of knots and jamming are still under investigation. It is recommended that a test will be done to evaluate these effects afterthe completion of the prototype. 5-5 5.2-2 Overall Weight The weight of the shearing assembly affects the design of the pole and operation of the entire pruning system. The larger the weight of the shearing assembly, the more difficult it will be to maneuver the extension pole. The pole analysis was done in conjunction with the shear assembly design assuming that the weight of the assembly would not exceed 15 pounds. 5.2-3 Cutting Torque Figure 5-5 illustrates how bypass blades inherently twist when cutting due to the offset of the blades. Branch Cutting Force Figure 5-5 Cutting torque diagram None of the powered pole pruners with bypass blades listed in Appendix A-2 has a dedicated device to reduce the transmitted cutting torque. Since these cutters are capable of cutting up to 2 W' diameter branches, cutting torque effects will most likely be similar. During the cut, extension poles act as a torsion spring reducing the transmitted force. The equivalent spring constant of a pole depends on diameter, length and material elasticity. Since the pole is rather long, reducing its spring constant, the dynamic force reaction applied to the tripod will be minimal. 5-6 5.2-4 Effective Cutting Diameter High branches of large diameter protruding near vertical from the tree raise issues of maximum cutting diameter. Figure 5-6 illustrates how non-perpendicular cuts of the branch increase the required cutting diameter to sever the limb. Perpendicular plane Figure 5-6: Non-perpendicular cutting Since our shears are purchased, we do not have any control of their maximum cutting diameter of an advertised 3 inches. Approximately 15 degrees of single axis angular misalignment is possible when cutting 3" diameter branches. With smaller diameters, greater angular misalignment is possible. In contrast, when the angle of attack of the cut is a dual axis angular misalignment, the angle will decrease. 5.3 Cutting Mechanics From experience and information gathered in the literature search, the cutting force requirements result from: • Friction of the blades • Branch diameter • Species of tree • Wood condition (green/dead) • Cutter type (anvil/by-pass) • Sharpness of blades • Cutter geometry 5-7 Detailed analytical studies of the mechanisms of woodcutting are not common in the engineering fi eld. Appendix B-3 contains information from the literature search of related physical data of operational force requirements of hand pruners capable of cutting up to three-quarter inch branches. Observation of the data shows that most models with Teflon blade coatings had a slight reduction in operating force. In addition, there are no significant differences of force requirements between anvii and bypass cutter designs tested. Data between all models varied significantly, and implies that blade geometry, not cutter type, is a major contributor to operating force. Force Requirements vs. Branch diameter 200 180 - 160 140 ::::- 120 • Seymour Smith/Snapcut 9T i @. ., 100 + Wallace/Fiskars 4135 � � 0 • Wallace/Fiskars 9110 u. 80 - Wolf/Burpee B 60 . 40 20 0 0.2 0.3 0.4 0.5 0.6 0.7 0.8 Branch diameter (in) L...... ------�------_j Figure 5-7 Reference data 5.4 Force Requirements In order to determine the force requirements for our shear/piston assembly, physical testing had to be done. Designing a test setup and procedure for the instron machine produced the required data to design the device. See Appendix F-1 for physical data from Instron machine. 5.4-1 Instron Fixtures To determine the required cutting force, custom retaining fixtures were used in an Instron machine with a 10,000-lb load cell measuring force exerted. The load vs. 5-8 crosshead distance is recorded during the test run on an incremented strip chart. By knowing the initial distance between the pins, the effective moment arm can be determined to calculate the moment about the hinge pin. Using the moment about the hinge pin allowed us to design the necessary stroke length and moment arm needed to cut through a 3" diameter branch with our particular linkage geometry. Figure S-8 Instron fzx tures 5.4-2 Wood Selection & Test Matrix To perform an effective force test for design purposes, the worst case scenario needed to be established. Dead wood vs. green wood is harder to cut in all types of wood. In addition, maple is the most difficult hardwood to cut in the greater New England area. Maple is readily available in the area and samples of air-dried dead maple branches were collected at random. The branch diameters ranged from 1" to 3" diameter 5-9 in the following precedence: 1.00 1.25 2.00 One Set 2.25 2.50 2.75 3.00 A set consists of an entire grouping of all consecutive diameters. Seven sets of data were collected overall during testing. Over ten linear feet of wood was cut between the blades after the testing was completed. 5.4-3 Wear Effects Increased force requirements over time due to blade wear effects were not observed in the data collected. The blade material is a steel formulationcalled Coronium™ that is proprietary to Corona ® who would not disclose the chemical composition or mechanical properties of the material. The blades are advertised as being forged, fully hardened and re-sharpenable. Hardness tests were performedon the blades and resulted in a hardness measurement of approximately 35 Rockwell C. Since wear effects are negligible, maximum statistical force and force vs. branch diameter can be characterized accurately. 5.4-4 Data Processing Using statistical software techniques advised by Prof. Benneyan, data beyond 2 sigma was eliminated by standardized residual regression using a statistical add-on within Excel. Only three data points were eliminated from the entire data sample. Two of the data points removed were due to unusually low force measurements for that particular diameter. It was observed during testing that the low force measurements were due to rotten cores within the branches. 5-10 Figure 5-9 Testing observations of rotten cores After filtering the data, linear, power, and exponential trendlines were fitted to the data sample. Using the R2 value, a statistical measure of how well the curve fits the data ranked from 0 to 1 with 1 being the highest, a comparison can be made of the curves. With an R2 value of .97, the linear trendline had the best fit of all the curves. RJrOOvs. DiCIT'Ieter I 111 Series2 I_U!lEa" I (Series2) - F�:J�o.er( Series2) �� (Series2) 1.COO 1.500 2.COO 2.500 3.COO Diameter(in) Figure 5-10 Trendline analysis 5-11 5.4-5 Maximum Required Foret:� Using the linear trendline, the confidence and prediction intervals can be calculated. The confidence interval defines the region of all possible orientations where the linear trendline may reside within a 95% confidence. The prediction interval sets the bounds of where all possible data points exist also within a 95% confidence. The following equations define the intervals' curve: (Confidence Intervals) (Prediction Intervals) The solid orange line represents the linear trendline previously determined. The red dashed lines and the solid blue lines represent the confidence and prediction intervals respectively. Confidence & Prediction Intervals of Force Requirements 2500 2000 g I Force 1 8 1500 I ;1--•CIPI � j 1000 500 0 �------�--�------�------����--��-r� 1.000 1.500 2.000 2.500 3.000 Diameter (in) 5-12 Figure 5-11 Confidence and prediction intervals The yellow point situated on the tip of the upper prediction interval represents statistical max load to cut a three-inch diameter branch. Since this data is composed for dead air-dried maple, this point defines worst case scenario and is acceptable for design purposes. To model worst case during the entire cut, the offset from experimental max load to statistical max load was applied to all experimental data points during the cut. This max force was then multiplied by the effective moment armto calculate the moment about the hinge pin. Once the curve of the moment required verses cutting angle was defined, the effective moment generated by the piston/linkage system verses cutting angle was superimposed for comparison. Effective and Required Moment vs. Angle 35000 30000 25000 :c I 20000 .5- - c 15000 � 0 ::E 10000 5000 0 1 0.8 0.6 0.4 0.2 0 Angle (radians) I.Moment Required • Obtainable I\1_S>ment I Figure 5-12 Cutting moment comparison The required moment is similar to a sine curve, which is expected when cutting a round branch. The required cutting force increases as the blades approaches the center of 5- 13 the branch, and tapers off after passing that point. The effective moment curve models the maximum possible moment that the linkage system can generate using 1200 psi. Its profile is due to the geometric effects of the linkage system moving relative to the moment arm during the cut. Although the piston/linkage system can generate much higher loads than required when initially cutting the branch, the system will never see more than the force required to cut at any time. Any force higher than the required force will advance the blade further and generate a maximum reaction force as defined by the required moment curve. For design purposes, mainly stress analysis, the required load curve is used for all calculations. This curve is the baseline used to determine all factors of safety for mechanical failure. 5.5 Linkage and Sleeve Analysis The design of the linkage arms and the sleeve was based on the analysis of the forces the piston generates on them. All of the components were designed to have a factor of safety of about three for increased durability if misused. The angles of the shears relative to the hinge pin were measured at both opened and closed positions to initiate the geometric analysis of the linkage system. See Appendix D--5 for MathCad sheets used. The dogbone length was then determined when tilted five degree away from the shears in the opened position to intersect the piston clevis. Using this fixed dogbone length to calculate the required geometry to open and close the shears, we determined the minimum stroke length to be 11.42 inches. From this, a 12-inch stroke length piston was selected and the basic dogbone geometry was finalized. Using the known piston force, the shear forces in the pins and tensile forces in the dogbones were determinedfor stress analysis. The pins were sized for double shear with torsion due to friction during rotation using a conservative coefficient of friction of .3, see equation (5-1). F F ( �_1,1 (5-1) - 1:= pm 4 2 d 2 {TCd2 J+�(--,;!-]4 5-14 a! Bearing & Critical L:�sile Areas Figure 5-13 Analysis of Dogbone Components The dogbanes were designed for pure tensile loading, see equation (5-2), since the moment transferred by the friction in the pins is negligible. The bearing areas of the dogbanes shown in figure 5-13 were equalized in all of the dogbane ends to optimize the design, see equation (5-3). --F (5-2) a1 = A.ec F (5-3) ab = t d pin thk --- 5-15 X-section B Figure 5-14 Analysis of Extension Anns The bending analysis at the critical areas of cross sections A & B were calculated from the reaction forces determinedaf ter the Instron testing was completed, see equation (5-4). -Me a = (5-4) 1 5-16 Point A "------1 Point B J Figure 5-15 Analysis of Sleeve As shown in figure 5-15, the buckling analysis was done for the length between points A & B. Point A is where the brackets that retain the shears are mounted, and point B is the end of the clearance slot for the dogbones. The entire sleeve undergoes compression from point A to point C where the end of the piston is mounted. However, the strength the moment of inertia between points B & C is several orders of magnitude higher than between points A & B. Knowing this, the critical sections were modeled as beams rigidly mounted at point B since these lengths would buckle long before the entire sleeve. The equivalent sigma allowable method for eccentric loaded was used to analyze the bending of the critical sections. Using the AISC (Amelican Institute of Steel Construction) code for determining the factor of safety, the critical sections were well within safe operation. The critical slenderness ratio is defined by equation (5-5). (5-5) 5-17 where Le = 2L for cantilevered beams (5-6) L., F.S � + illj lcl (5-7) % � �J -i(�r 3- cr J 1 cr o cr (5-8) a au = -F.S. Calculating the total compressive stress with equation (5-9), it is compared with the allowable compressive stress defined by equation (5-8). If the total compressive stress is less than the allowed compressive stress, the beam will not buckle under the load analyzed. F Me =- (5-9) a A + -I 5-18 5.6 Prototype vs. Production Several design decisions were made in making the shear assembly prototype. Because of financial considerations, the desired prototype could not be fabricated. The piston desired for our initial prototype was a 2-inch bore cylinder, and would weigh approximately ten pounds. Because the piston cost almost $600, an inexpensive piston needed to be purchased to maintain prototype budget restrictions. The piston selected for the prototype is less than $100, and has a 2-inch bore piston with a 1.125-inch diameter piston rod capable of 12" of stroke as needed. The maximum operating pressure is rated at 2500 psi. The entire weight of the piston is about 25 pounds. The weight of this piston alone is well above our initial overall shearing assembly weight of 15 pounds. This piston was selected to keep the same stroke length to eliminate re-design of the linkage system. The desired sleeve was made from an aluminum square tube, which would have had to be purchased for about $60. A steel square tube was substituted since it was readily available at no cost. The steel tube also increased the weight significantly to further force our prototype to be used as a "proof-of-concept" testbed. This prototype would focus on the verification of the cutting process and component stress analysis. Weight optimization would not be a factor in the prototype design beyond the piston and sleeve. 5.7 Prototype Testing Results After completion of the prototype construction, a pressure gauge was installed in line with the hose from the pump to the piston. This gauge was used to observe pressure measurements during the cut. The prototype successfully cut branches up to three-inches in diameter repeatedly. Initially, the tests were performed without the air spring feature to verify our cutting force requirements with the linkage geometry. For the cylinder used, the predicted maximum system pressure to cut three inch diameter dead maple, would be 1500 psi. While cutting our specimens of dead three-inch diameter maple, the maximum observed pressure was about 1600 psi. A difference of only 100-psi in system pressure from the predicted value. 5-19 Figure 5-16 Picture of Prototype The pressure while cutting from about mid-·cut to near the completion of the cut remained nearly constant, and in general followed the curve profileshown in figure 5-10. This behavior due to the geometry and reaction force of the wood was accurately predicted and verified. After verifying the cutting force pressures and behavior, the air spring feature was enabled. The maximum operating pressure increased to about 1750 psi when cutting three-inch diameter dead maple. However, due to the high friction of the piston seals, the air springonly had enough force to open the shears to about 75% of their maximum spread. Approximately 20-30 pump strokes, depending on the amount stroke used during each pump stroke, are required to completely cut through any branch up to a diameter of three inches. The entire cutting process from the engagement of the shears, to completion of the cut, takes under 30 seconds with a reasonable amount of pumps per second. 5-20 5.8 Summary of Shearing Device Design A solution to the air return's lack of fully opening the shears would be to pre-charge the opposing end of the cylinder with compressed air. The increased force of the pre charge would force the shears to open enough to cut a three-inch branch without manual assist. The pre-charge would also require a higher maximum operating pressure to maintain the required force to cut the branch. With the piston purchased for the proof-of concept prototype, this would be easily attainable since the maximum observed pressure was 1750 psi, and the piston is capable of up to 2500 psi. Within this project, the group was unable to test the pre-charge concept on the prototype.. Although the prototype did not contain all of the desired components, various improvements can be made to reduce the weight of the desired prototype. The most significant weight reduction can be accomplished by designing a custom lightweight piston to actuate the device. Since most commercially available hydraulic pistons focus on overdesign for safety, their weight is typically excessive. Steel is predominately used throughout the piston and cylinder components in commercial cylinders. A custom design using lightweight materials would decrease the weight of the entire assembly by about a factor of two. The pistons used on commercial pole mounted shears incorporate custom pistons that focus on lightweight design. Financial and time constrains did not allow the group to consider design and fabrication of our own custom cylinder to accomplish our goal. The extension arms used to provide the necessary moment about the pin are another factor in producing a heavy assembly. The only solution to reduce or eliminate their weight would be to design our own blades with handles custom suited to meet our needs. These blades would require a complex milling process that is beyond the capability of the group. The heat-treating needed to make long lasting and durable blades was also an impedance that helped us to form our decision to retrofitextension arm to the existing blades. 5-21 6. Pole Design One concept remains the same during the design process, regardless of the final design of the shearing device, was the pole design. The pole is a telescoping extension that was designed to reach 25-ft, as stated in the requirements. The pole has a base tube OD of 3.75", and is made up of eight interlocking pole sections. Figure 6.1 is an illustration of the pole design. Figure 6-1 Telescoping Pole Design The figure shows the pole and the locking collets between each section. Due to the length and the moment created by the pole, it will be mounted to a tripod. The tripod reduces the forces required from the operator to use the shearing device. This chapter will discuss the design of the pole, and explain the development of the design decisions. 6-1 Chapter 7 will discuss in more detail the design of the tripod and explains the decision to use the tripod and handles. 6.1 25ftRequirement This tree-pruning device requires a pole system that will enable the pruning device to reach heights of 25 ft. In order for this device to be a marketable device not only will it need to reach heights of 25 ft but it should be able to reach heights lower than 25 ft. As stated in Chapter 3, the state of the art, there are three common types of poles on the market today. A telescoping extension pole is the best choice for the design of this tree-pruning device, so the user can adjust the length of the cutting device to reach branches at various heights. The geometry and material selection of the pole was critical to optimize its strength and weight. Telescopic poles with members of different constant cross sections can be designed to provide an almost uniform bending stress within the members. Tapered segments can be designed to achieve near perfect uniformity of stress to produce a pole optimized for weight reduction. However, tapered segments are difficult to lock at variable amounts of engagement to provide adjustable pole lengths, and are generally more expensive than constant cross section poles. Dynamic effects need to be considered when comparing pole types since; acceleration and vibration effects are significantly different between basic, segmented and tapered poles 6.2 Material Selection Selecting the material for the telescoping pole was a very important design decision for reasons of weight to strength ratio. Several materials were under consideration aluminum, fiberglass and carbon fiber. Aluminumhad a higher "weight to strength" ratio than the fiberglass and carbon fiber so it was eliminated immediately. Fiberglass had a good "weight to strength" ratio and is non-conducting, but it was also ruled out because carbon fiber has a lower weight to strength ratio. Carbon fiber was chosen because of lightweight to stiffness ratio. There are various types of carbon fiber, which range from common commercial types of generic carbon fibers to trademark carbon fibers (i.e. Thomel®, BASF®, 6-2 Ultramid®, Electrafid®, etc). After comparing the various types of carbon fibers it was determined that the Thorne!® carbon fiber would be the material used to make the telescoping pole. Thornel® was chosen over the others because of its unique properties. The density, modulus of Elasticity, and Ultimate tensile strength were very appropriate to the design of the pole, see Appendix C-2 for the material properties, and comparison values. 6.3 Mechanics of Telescoping Pole The mechanics of the telescoping pole are as follows. The base pole acts as a shell to the rest of the extension poles. Each coinciding pole section shells the remaining sections. The outer diameter (OD) and wall thickness of the outer pole determines the OD of the pole inside. This relationship is seen throughout the telescoping pole system from the first extension to the last extension. The telescoping extension poles functions like an antenna on a car, or the antenna on the back of some television sets. The pole that is extended out from the shell pole can only be extended out of the enclosing pole the length of itself minus the distance of overlap between the poles. The overlapping distance between the sections is related to the diameter and length of the pole. A general rule to 5 the length of the overlap is that the length of the overlap should be 1 /8 of an inch or up to 1.5 times the diameter of the overlapping poles. One reason for the selection of a telescoping extension pole is its ability to extend in this manner. Each internal extending pole is designed to have an enlarge area at the end, which will stop on the coinciding enlarged area of the external pole. The enlarged areas are only used to stop the pole at its furthest extension, and prevent the pole sections from coming apart. Each section of the pole must have a locking device installed to adjust to lengths that are between the minimum length and total length. As stated in Chapter 3, the state of the art, the locking device that is design for this pole is lthe external collet, Figure 6-2. 6-3 Figure 6-2 Internal view of telescoping pole with externalcollet The initial pole design was benchmarked from the Trailblazer Products "Xtend-A Pole" (Figure 3.14). The telescoping pole is designed to have eight pole sections. When fully extended the pole will have an overall length of 29.167ft. The eight sections of the pole will have 4-inch overlaps. The overlap of the pole has an effect on the weight of the pole, which will in tum effect the total deflection. The telescoping pole for this the pruning device has a base pole OD of 3.75 inch and has wall thickness of 0.125 inch, with eight telescoping sections, the final pole section will have an OD of 2.50 inch. See Appendix B-3 for an AutoCAD sketch of how the pole's dimensions can be adjusted to a change in OD and wall thickness. 6.4 Static Deflection Analysis A static analysis to replicate a 29.167-ft, eight sectioned, pole was performed to find the deflection of the pole using Excel. Three types of calculations were performed for the analysis to gain knowledge about the static deflection of the pole • due to the distributed weight of the pole. • due to the weight of the pruning device. • due to the angle of operation. The first two types of calculations were performed with the pole resting at zero degrees, the horizontal plane. The third calculation determined the effect of changing the angle of operation, integrating the deflections due to combined weight of the pole and pruning device. All three-deflection calculations are based on a similar free-body diagram. 6-4 Each section of the telescoping pole was assumed pinned at the left side and free on the right. Figure 6.3 is a sample section of the pole Fr0_1) FrI· Figure 6-3 A sample of the fr ee body diagrams for the pole deflections where Fr(i-1) represents the reaction force applied at the end of pole section from the section extending out to the right. In the initial section, for deflection due to the weight of the device, the Fr(i-1) is equal to the weight of the device. M(i-1) is similar to the Fr(i-l) in that it is the reaction moment caused by the section extending out to the right. The Wi is the distributed weight of the section; Wi is placed in the center of the section for moment calculations. To maintain equilibrium, the reaction forces and the sum of the forces and moments were taken on the left side of the current section. The following sections of section 6.4 will walk through the equations used to calculate the static deflection. See Appendix D-6 for samples of the sum of the forces and sum of the moment equations. The common variables for the deflectioncalcula tions were the • volume per section • weight per section • moment of inertia per section See Appendix C-6 for the formulas and calculated values for these common variables for each section of the pole. The volume per section is dependent on the wall thickness, the initial OD and length of section. The weight (W) is dependent on the volume of each section and the density of the material used. The moment of inertia (I) is dependent on 6-5 the OD and ID of the section. The Excel programs were written so that these variables were linked. If the OD of the base pole was modified, then the given wall thickness would cause the other seven pole section to comply with the physical dimensions of a telescoping pole. Since the volume was dependent of the OD, the volume calculations were linked to the OD cell as well. There are two constants for the deflection calculations, the Modulus of Elasticity (E) and density (p) of the material. The modulus of elasticity is a measure of stiffness for the material. The density of a material is its weight per unit length. A material with a higher density then weighs more than a material with lower density. With all the variables calculated the calculations of the different deflection could be completed. 6.4.1 StaticDeflection vs. Weight of Pole The first calculation perfom1ed on Excel was the deflection caused by the weight of the pole on itself. The deflection due to the weight of the pole, equation 6-1, is then calculated 4 WL 8 = (6-1) w 8EI In addition, the section's angle of deflection due to its weight, equation 6-2, was calculated. WL3 e = (6-2) w 6EI When calculating the deflection of each section the moment caused at the end of each section of the pole caused a deflection that needed to be included. The total deflection, (jT, is then calculated using equation 6-3, (6-3) The moment force was then placed into the deflection for moment on a pinned beam, equation 6-4, (6-4) 6-6 where the is the reaction moment induced into the pole by the applied force of the M (Mi) weight of the pole. The moment forces also produced a similar angle of deflection like the deflection due to the weight of the pole, equation 6-5. () ML = (6-5) M El When calculating the total deflection of the pole due to the weight, the initial deflection of the previous section causes an angle of deflection. It was important to find the deflection that was caused by the deflection of each of the previous poles on the next pole, in addition to the deflection of the weight of the pole. This is because the deflection of the first pole places a different initial angle on the second pole and so on throughout the pole. This calculation was included to compensate for the initial starting angle of each pole. The only section that follows the angle of operation is the first pole section. Each additional extension causes a deflectionon the previous pole. The angles calculated from the weight, force and reaction moments were summed together to get a total angle of deflection and then a fourth deflection value equation 6-6 was found. £5 4 = L cos(2:6) (6-6) The deflection of the pole due to its own weight was 0.3167 inch, allowing for a high accuracy of the pole placement at 29 .167ft away. 6.4.2 Static Deflectionvs. Weight of the Device The second analysis performed on Excel was done to find the deflection of the pole due to a weight applied to the end. This prototype analysis used the same free body diagram principle for the weight of the beam deflection. The only difference is that the last extension pole's free body diagram had the weight of the device applied to the right side, rather than a reaction force. The deflection of each section in the beam due to the applied force at the end of the pole and the angle of each section which the deflection caused were calculated using equations 6-7 and 6-8 8 FI3 (6-7) FL2 (6-8) = () = F 3El F 2El where F is the force applied at the end of the pole by the weight of the tree-pruning device. 6-7 Equation 6-7 was modified, to include Ciw , to look like equation 6-9. (6-9) Equations 6-4 and 6-5 were also applied to the calculation for deflection due to the weight of the pruning device at the end. Using a pruning device that weighs 15 lbs., the deflection of the pole was calculated to be 1.0151 inch; this was an acceptable value of deflection. To find the total deflection of the telescoping pole all four of the deflection values from the weight, force, moments, and angle of deflection were summed. Figure 6-4 is an excel graph that illustrates the trend for the pole deflection vs. the total weight of the device and pole. As seen in the curve, the pole reacts linearly to the weight of the device attached to the end. This also provided a direct relationship between the static deflection of the pole to the eight applied to the end. 7 6 / / / / 2 / -- / / 0 0 10 15 20 25 Weight (lbs) r·· 1 1--+- Deflection at 0 degrees 1 Figure 6-4 Weight of pole and device vs. the deflection in pole 6-8 Before performing the third analysis on the angle of operation, it was necessary to relate the first two tests. The Excel sheet used to perform the first two analyses were manipulated so that by changing the diameter of the first pole section it effected all the data. The change in diameter would change the volume, which would change the weight, which would increase the deflection due to the weight, and so on. 6.4.3 Static Deflectionvs. Angle of Operation The third and final static calculation performed on the pole design was the deflection due to the angle of operation. The angle of operation is defined as the angle between the pole and horizontal when the operator is holding the device or it is resting on the tripod. This angle in most cases will be from 45 degrees to 85 degrees. The reason for not having the pole go past an angle of 85 degrees is to avoid being directly below the branch that is being pruned. On the other hand, operating the device at an angle of less than 45 degrees does not take full advantage of the length of the pole. To calculate the change in deflection due to the angle of operation the y-component of each force was used in the formula for deflection. Figure 6-5 illustrates the effect of changing the angle of operation over the range of 0 degrees to 85 degrees compared to the horizontal deflections calculated. 7 .------. 6 +------ g 4 +------�'---7'""''--- 5 ti � � 3 +------;;7""------::;,..-c---�=------�= 0 5 10 15 20 25 Weight (lbs) �Deflection at degrees --- Def ection at degrees �Deflection at 4S grees ..:::'.__Deflec ion at degr �Deflection at degrees 0 � _ 30 6-9 The first noticeable observation of the data points graphed is the decrease in deflection with the increase of the angle of operation. The worst case deflection for a static pole is parallel to the ground at zero degrees. As the pole is lifted up, to a more efficient angle of operation, the deflection of the pole decreases making it more effective to maneuver. Another observation of this analysis is that the additional weight at the end of the pole effects the deflection closer to horizontal, more so than it does in the vertical position. After the initial calculations were completed, it was determined that a more dynamic analysis of the pole was needed. 6.5 Additional Analysis Required for Pole Design The additional analyses needed to better design the pole for the pruning device include such details as • The effects from the cutting forces produced by the pruning device. • The effects of dynamic motion on the pole 6.5.1 Additional Effectsof the Cutting Forces on the Pole The conceptual idea for the pruning device is shear. The device has the potential for applying additional forces to the pole. The pruning device will be: fixed to a hollow sleeve, which will fasten to the last section of the telescoping pole. The hollow sleeve was designed to absorb or withstand the forces applied by the pruning device, to avoid additional stresses from the reaction forces due to the cutting mechanism. In addition to the design of the sleeve to reduce additional forces, the shears were made to be symmetric to the pole. This was done by attaching the by pass blades to the center of the sleeve instead of on the side. The weight of the sleeve was included in the weight of the pruning device, in the previous calculations for static deflection due to the weight of the device. The hollow sleeve concept allows the telescoping pole design to be used with other devices that have similar weights to our pruning device. Since the additional effects of the shearing device were taken to be negligible, the only additional forces to consider in the design of the pole are the dynamic effects. 6-10 6.5.2 Additional Effectsof Dynamic Motion on the Pole The dynamic motion concerns that arose early on when doing the static deflections grew to be one of the hardest analyses to perform on the pole. The team was made aware of a software package, Working Model, which does dynamic analysis. After reviewing the benefits of such software, it was decided that it was not going to be beneficial for one of the team members to learn how to program on Working Model since time was limited. Without the knowledge on how to use other current software such as ADINA, ANSYS or NASTRAN to perform the dynamic analysis with finite elements, Professor Hashemi suggested we use hand calculations in junction with MathCad to calculate the dynamic response. The use of a spring-mass damper system was the approach used to determine the dynamic effects. This method allows for the determination of the natural frequency and maximum deflection. The natural frequency is needed to determine whether the pole will fail. If the natural frequency of the pole matches that of the oscillations from the dynamic motion, the pole will fail. The spring-mass damper system uses the equivalent mass and spring constants of the system to simulate the actual pole. Figure 6.6 is a visual on what the spring-mass damper system will be for this system. ------X min --t---- X (t=O) X max Figure 6.6 Spring-mass damper system .for equivalent system 6-11 To fi nd the mass equivalent (Meq) it was necessary to evaluate the pole section by section. Equation 6-10 is the formula to determine the Meq· � l . 2 M y dx := Meq (6-10) .Ymax • 0 Appendix D-7 shows the expanded version of this equation over the entire pole, section by section. The value for equivalent mass is 20.766 lb. This value represents the weight of the entire system, pole and shearing device. It was then necessary to determine the spring constant equivalent (keq) to the pole. This was done using equation 6-11 as seen below. p -- := k (6-11) eq Appendix D-7 shows the expanded version of the spring constant equivalent for the entire pole, section by section. The value for the spring constant equivalence is 22.974 in-lb. When both the Meq and the keq were determinedthey were placed into equation 6-12 to determine the natural frequency W (6-12) n :=�Meqeq The value from the natural frequency, 1.052 Hz, was still not enough to determine the maximum deflection of the pole in dynamic motion. There was still one more unknown required to complete the analysis of the pole, the damping coefficient The damping coefficient is determined with physical testing and for this reason, it will be discussed in the prototype section. The team was able to purchase a telescoping pole made of aluminum, scaled 1/3 linearly. By testing and analyzing the prototype pole using the same pole analyses used to predict the effects on the pole design, the team was able to estimate the dynamic effects of the pole design. Using the formulation from the design analyses the same information for Meq and keq could be determined for the prototype. 6- 12 6.6 Prototype To demonstrate the effects that the pole will have, a scaled version of the pole was purchased. Due to the cost constraints it was not, feasible to manufacture or buy a 29-ft telescoping pole made of the Thornel®Carbon Fiber. Therefore, the team decided to scale the prototype linearly and purchase an 8 foot pole made of aluminum. 6.6.1 Scaled Prototype The aluminum prototype pole was scaled linearly approximately by 1/3. There are some physical differences between the pole design and the prototype pole. The pole design is that of a telescoping pole with eight interlocking pole sections that has a tight fit and utilizes external-locking collets to secure the position of the pole sections. The pole design also has specific wall thickness' and lengths for every section of the pole. The overlap on the pole design was approximately 1.5 times the diameter of the pole sections. The prototype pole was purchased from JTD products. The prototype pole has eight interlocking pole sections with internal locking collets, but with no tight fit between the pole sections and the wall thickness' and lengths are constant for each pole section. The over lap on the JTD pole is constant to the size of the collet, which is unknown. The importance of this difference is further addressed in the analysis of the prototype pole. There is also a difference between the material properties of carbon fiber and aluminum. 6 Thorne!® Carbon Fiber has a Modulus of Elasticity of 120xl0 where as aluminum has a Modulus of Elasticity of only 10x106, again this difference will have an effect on the prototype analysis, which will be discussed next. 6.6.2 Analysis For a better understanding of the analyses performed on the pole design, the team performed the same analyses on the prototype pole. This included redoing the static and dynamic analyses. The prototype pole was weighed and measured dimensionally in length and the wall thickness. These values were placed in the MathCad program to calculate the Meq and keq of the prototype pole. The MathCad program also was verified by actually weighing the prototype pole and determining its actual weight. The measured weight was then compared to the weight determined by the MathCad program and was determined to be within 1% error. This error was attributed to the uncertainty of the weight of the locking collets. The Math Cad program also made some assumptions about 6-13 the pole design, which are not true about the prototype pole. The program assumes that the fit between the two over lapping sections is a tight fi t with no gap. This eliminates any additional deflection of the pole. Except the prototype pole is not a tight fit and does have gaps between pole sections, which cause additional deflection. The effects of the gap were attributed to the excess deflection between the prototype pole and the prototype pole analysis. In order to perform the analysis properly it was necessary to determine what the appropriate weight to add to the end of the prototype pole is to simulate the pole design. This introduced the use of non-dimensional analysis, which is how the team overcame the dimensional difference as well as the material property difference between carbon fiber and aluminum. Using the final value for the static deflection calculated on the pole design and then dividing that value by the total length of the pole design, a non-dimensional value was determined for the deflection per unit length. Then the material properties of carbon fiber were replaced with those of aluminum in the MathCad deflection program. The new deflectionform ula over the total length of the prototype pole was then set equal to the non-dimensional value of deflection per unit length and a scaled prototype weight was determined. The value for the weight was then substituted into the MathCad program to calculate deflection, which produced a predicted value for deflection of the prototype pole. This value was then compared to the expelimental value, which was determined by placing the determined scaled load for the prototype weight at the end of the prototype pole and measuringthe deflection. The prototype deflection value was within 60% of the predicted value from the MathCad. This difference was significantly higher than expected. Since the difference between the design pole and prototype pole could not be determined it was assumed the difference between the theoretical and physical values were due to effects of the gap, overlap and the fit between pole sections. In order to verify the dynamic analysis it was important to test the prototype pole, which required testing for the damping coefficient of the prototype pole. 6- 14 6.6.3 Physical Testing for Damping Coefficient Since the damping coefficient value can not be determined mathematically with out physical testing of the material, it was necessary to petform a physical test of the prototype pole. As stated earlier, it was not feasible to purchase a pole made of carbon fiber, so the team analyzed and then tested the prototype aluminum pole. To perform the test an accelerometer was placed at the end of the prototype pole. The accelerometer was connected through an output amplifier to a strip chart recorder, which was for plotting the acceleration vs. time. The test consisted of deflecting the prototype pole with an initial displacement and allowing the pole to oscillate until rest. Twenty-two runs were petformed in order to get results that are more accurate. (Appendix F-2) The information collected from the acceleration vs. time charts were used in determiningthe coefficient of damping for the system, which in turn led to the final dynamic motion solution for the pole. 6.6.4 Calculating Damping Coefficientand Equation of Motion The test petformed on the prototype pole generated acceleration vs. time graph, which showed that it is an underdamped system. Using the log decrement method from the peaks of the graph, Equation 6-13 ' 1 I X\ I 1 ' ··- �--- i ·hJ.i -1 � \ x .- (6-13) \2·n -� I j . J=� 2 the team was able to solve for the damping ratio of the prototype pole. Since the damping ratio is equal to the damping coefficient (C) of the pole over the critical damping (Cc) factor, equation 6-14 (6-14) Now that the Meq, keq, and C of the prototype pole are known, it was possible to place those values into the Equation of Motion. Since C (6-15) 6-15 Equation 6-15 was placed into an Excel file, and then plotted the deflection vs. time, Figure 6-7, to determine the time requirements for the pole to stabilize, and to visually see the deflection of the pole. c Ojrmi Effects 1.2 r------·------ - - ; 0 +--f---'.'f--fr-----\�---.--+1''----'1.-.---1· E 14 16 18 Cl.) (.) .!! -o.2 +---t----,1*---+---!!'------c.. Cl) 0 -Q.4+---+--'1''---"''t::-- �------ -Q.8 .L------·------' tirre(t) Figure 6-7 Dynamic Response of Pole Comparing the results of the prototype to that of the design and the optimal results, we can see an improvement of dynamic response. As you can see in fi gure 6-7, the time for the prototype pole and the design pole are relatively equal. The difference between the two curves is that the prototype oscillates at a higher frequency than the design with similar time requirements. The optimal design, as seen in Figure 6-7, reaches static equilibrium at the same time rate as the design and prototype curves, with the exception of the oscillations. The optimal curve shows that there is no oscillations occurring, and 6-16 that the pole returns to its static position with less force being applied to the pole. The forces being applied to the pole when in motion is the weight of the device times the acceleration at any given time. In order to calculate the force being applied to the end of the pole it was necessary to determine the acceleration at the end of the pole. By takjng the second derivative of the position equation, 6-15, the acceleration can be determined, Appendix D-8. The acceleration at the peak point of the greatest amplitude the maximum force being applied to the pole was calculated. After calculating the maximum force, it was placed into a failure analysis. The failure analysis determined that the pole would not break under the dynamic load applied by the device at its greatest acceleration. The optimal design curve had the lowest acceleration, which produces the lowest force applied to the pole. Given better resources to manufacture a pole, the optimal design curve would have been the final goal of the team. Figure 6-7 only evaluates the time required for the pole to oscillate to a static position. In order to calculate the maximum deflection the Meq. keq and C must be place into the Equation of Motion, Equation 6-16. 2 d x dx (6-16) Meq ·-+C·-+k ·x := 0 de dt eq With the acceleration at any given time already calculated, it was necessary to take the first derivative of Equation 6-15 to find the velocity of the pole at any given time (t) in order to complete Equation 6-16. By placing the values of acceleration and velocity into Equation 6-16, the team was able to determine that the maximum deflection due to the weight of the device at the end of the pole would create difficult control problems. In order to obtain more control at the end of the pole, the pole should be moved at a rate slower. By slowing the rate of motion down the pole will act more rigidly, thereby reducing the amount of deflection in the pole and increasing the accuracy of the device. 6.7 Relating the Prototype Pole to the Pole Design Thomel® Carbon fiber has a Modulus of Elasticity that is more than five times that of aluminum. The Modulus of Elasticity (E) is in the denominator of the deflection calculations so as the value of E increases; the amount of deflection would decrease. With geometrically similar beams the deflection of the beams decrease with an increase 6-17 in E. The value for moment of inertia for a pole is dependent on the diameters of the ID and OD of the pole. As the pole diameter increase, the moment of inertia increases. Moment of inertia is also dependent on the wall thickness, as the wall thickness increases so does the moment of inertia. We predicted the value for damping coefficient of the design pole, using the relationship between the material properties and how they relate to deflection. The damping value for the pole design was predicted to be about three times that of the prototype pole. This number of "three times" came from looking at the increase of the moment of inertia of the design pole and the increase in Modulus of Elasticity. The predicted value as well as the information on the material property difference shows that the design of the pole will have a better response to loading and motion than the prototype pole. 6.8 Summary The telescoping pole that was designed for the pruning device is 29.167 ft in length, weighs approximately 22 lbs., and is made of Thorne!@carbon fiber. The team used a 1/3 linear scaled aluminum pole to evaluate the design process and computer aided analyses. The MathCad and Excel analyses proved to be accurate, when relating the physical testing results to the prototype analyses. The pole proves to have the characteristics that are required for positioning a 15 lb. device 25 feet above the ground. The pole reacts to the weight of the shearing device in the following manner • Statically the pole deflects lless that four inches in the horizontal plain • Dynamically the pole will oscillate to much to control when moved quickly From the displacement graph in fi gure 6-7, in a period of less than 10 seconds, the pole will returnto its static position. Due to the total weight of the pole when the shearing device is attached to the end and the moment forces created by the oscillations a tripod will be used to hold the pole. 6-18 Chapter 7 Tripod Design As shown in the previous chapters, the weight of the telescoping pole, under best case design was 12.6 lbs. and the weight of the cutting mechanism was 15 lbs. The force to carry, hold and maneuver the pole could then be calculated once these weights were finalized. The overall weight of 27.6 lbs. was not a concern for the operator to carry, being an acceptable weight. However, when the telescoping pole is extended to the full length and titled at an angle less then vertical, the forces that the operator must apply to keep the pole from tipping further are large. The operator would hold the telescoping pole to the side with their hands approximately 2.5 feet apart in a postulated grip. At only 15 degrees from vertical the operator would have to apply close to 40 lbs. of force with their forward most hand while supporting the over all weight of the assembly, 28 lbs., with their other hand. The magnitude of these forces is not acceptable for extended periods. Another area of concernis if the operator allows the pole to tip past an angle in which they can comfortably hold. As the angle of pole tip from vertical increases, so does the moment about the base caused by the weight of the shears as well as the weight of the pole itself. The operator must counter act this moment to avoid the pole from gaining dynamic momentum and tipping. For instance at an angle of 45 degrees the operator must now apply over 80 lbs. of force while still holding the device. These forces are too high, and impractical for safe use. A further area of concernwa s the complexity of operation of the device. By having the shears hydraulically activated with a manual pump the operator must use a foot pump to cut through the tree limb while they have to using both hands to hold the telescoping pole. This design requires the operator to be ambedextrerous and is a challenging task. Therefore, a device was needed to accept the weight of the device and to allow the operator to maneuver it easily. A tripod assembly was designed to be attached to the base of the telescoping pole. 7-1 7.1 Initial Design Concerns The use of a tripod to accept the weight of the device meant that the telescoping pole would be connected through the middle of the tripod assembly and allowed to pivot from there. The distance from the pivot point to the end of the telescoping pole could then be determined and the forces that the operator would be required to input could be calculated. The further the distance from the end of the pole to the pivot point the larger the moment arm and the more leverage available to the operator. However, the height of the pivot point is limited by the fact that the operator must be able to extend each segment of the telescoping pole. The point where the pole is connected to the tripod must be below the area of pole extension. The ergonomically best area for this extension starts from the waist and ends at the head. Therefore it was determined that the pivot point be at or near the waistline. Placing the contact point at this location set the tripod height. Even though the weight of the device no longer had to be held by the operator, there was still the concern of the forces needed to maneuver the pole. The forces that the operator feels were calculated by putting them into an Excel spreadsheet. It was found by using a moment arm of 3.5 feet, or roughly the waistline, the operator would have to apply 32 lbs. of force to control the telescoping pole. It was found, however, if an extra weight or counterbalance were added to the end of the telescoping pole, the force the operator would have to input would be minimized. These calculations were made by takingmoments about the pivot point and are shown in Figure 7-1. Shearing Device "fA1= �hearingdke * Lgt� -�ounterbahce * Lgh) Counter Balance Figure 7. 1 Moment Equations 7-2 The Figure 7-2 below plots the operator-input force vs. counter balance at various angles of operation. Force vs Counter Balance 29.00 +------] I -- .. - Ii g ----- � 1-15 degrees -14 degrees 23.00 +------ -- � a;� I 13 degrees Ill ---� 12 degrees I -1�·�M•"o 1 degrees jI I jI 10d_El(!F."_e� 17.00 +------ 15.00 �----�------14 16 18 20 22 24 26 Force (lb) · J Figure 7-2 Force vs. Counter Balance Weight Another area of concernwas the ability of the device and tripod to tip, because the counter balance weight is a factor of stability, both concerns of tipping and counter balance were addressed simultaneously. Although the device would theoretically not tip if the legs were made infinitely long, there would be a point where the length of the legs would encumber the ease of transportability and setup. Therefore it was important to make the legs long enough to avoid tipping, but not excessively long. The tripod, having three legs, has the largest tendency to tip when a force is exerted perpendicular to the line between the ends of two of the legs. 7-3 This line is the tipping plane shown below in Figure 7-3, the over head view of the tripod . .....- Tipping Plane Figure 7-3 Tipping Plane Diagram This plane is the fulcrum in which the tripod will want to tip about. On one side is the weight of the shearing device at the end of the telescoping pole and on the other are the weight of the tripod and the counter balance weight. The pole weight is concentrated at the midpoint. This equation was put into an Excel spreadsheet and the counter balance weight and the tip angle of the tripod was determined, Figure 7-4. ------. 6 00.0 ·- 5 00.0 ------: -2 o- ib�-(1-5 -,-d .-g-ree-s �) 1 -e--20 lbs (1 0 degrees} ------�----�- -,--25 lbs (1 5 degrees) 4 00.0 -···---�--- -e- � 2 5 lbs (1 0 degree) j-1 5 lbs (1 5 degrees) 300.0 � --- �-�-J�..!.J � 0 de g re-"'e s. ,_) _I"""""" ---, 2 00.0 :a � 1 00.0 ¥E 0 ::! 0.0 �1 00.0 -2 00.0 ·3 00.0 ·4 00.0 -500.0 Distance (in ) Figure 7-4 Tipping Plane Distance 7-4 The chart shows the moment about the tipping plane as a function of the distance in which the legs extend from the center of the tripod. The various colored lines represent different counter balance weights at increasing pole angles from vertical. It can been seen that the distance the legs extend greatly depends on the counter balance weight. Also noticeable is the negative slope of the trend line, this shows that the closer the tripod legs the greater the force required to prevent tipping. Another area of concern arose at this point in the tripod design, which was the transportability of the entire device. It was found that the increasing of the counter balance reduced the force the operator has to input to the device as well as decreasing the length of the tripod legs to avoid tipping, both positive aspects, however the increased weight would decrease the mobility of the device. During transportation the legs of the tripod and the telescoping pole would be collapsed, the shearing section would be removed altogether and the device would be rolled away with the use of casters on 2 of the tripod legs. The free body diagram below, Figure 7-5 describes the force the operator would have to exert to hold the device during transportation. Operator Input Carryingheight ----7 (Waist) Telescoping pole weight ,�ce weight ------Figure 7-5 Transportation F.B.D. Next the team, with the aid of Professor Yeager, an industrial/ ergonomics engineer at Northeastern University, took the three considerations • Counter Balance Weight • Tripod Leg Length • Ease of Transportability 7-5 Which each depended on each other and had positive and negative aspects to the design, and decided what the appropriate values of each would be. 7.2 Decision on Tripod Aspects It was determined that the maximum acceptable tilt from vertical for the telescoping pole would be 15 degrees. At this angle the base of the tripod will be 6 feet away from the cutting device and subsequently the falling tree limb. By using 15 degrees it was determined that a counter balance weight of 25 lbs. added to the end of the telescoping pole would reduce the operator input to 25 lbs. of force. By using that same counter balance weight the tipping plane was reduced to a distance of 14 inches from the center of the tripod. Taking a marginal factor of safety, the team decided on using 21 inches, which correlated to ends of the tripod legs being 6 feet apart. The team felt that this distance was appropriate for the operator to walk between and maneuver the telescoping pole, while not being so large that it would be difficult to set up in a small area. The operator applying 42 lbs. of force during transportation could then maneuver this entire device. It could be argued that the addition of the counter balance weight could be eliminated and its benefits, shorter tipping plane and force to maneuver, could be made up elsewhere, however the team feels that it is more important to look at the aspects of safety. The decrease in operator force during maneuvering and the non-tipping aspect decrease the chance for operator injury during use. The 42 lbs. of force for transportation although high is a type I lever arm and allows the operator to carry the device in a wheel barrow or golf cart fashion. 7.3 Tripod Criteria There was an extensive search for a tripod suitable for this application, however, none were found that meet the following three requirements. • Non-center braced • Support overall weights • A void tipping The tripod design had to be non-center braced to allow for the telescoping pole, which would travel through the center of it, to be able to pivot about the center. The tripod also 7-6 had to be able to support the overall weight of the system. The tripod would have to support 27.6 lbs. of pole and shears, and the additional counter balance weight. Finally the tripod would have to avoid tipping. The nature of the device would require that the tripod be put under many external forces that would have the tendency to tip. After many companies were contacted, it was found that there is no such tripod available on the market. If a company were to provide the team with a tripod, it would have to be a custom built unit, costing up to a thousand dollars. Instead of having a custom unit built, the team, under the direction of the advisor, determined to build a tripod from scratch. 7.4 Design Components There was various aspect of the tripod design that required special detail. Those included the ability of the telescoping pole to be maneuvered while attached to the tripod assembly. While being attached it also had to be locked, allowing the operator to move away from the entire device to operate the hydraulic pump. The legs of the tiipod must also accommodate uneven surfaces when set up. 7.4.1 Design Components (Spherical Plain Bearing) The biggest component of the tripod design was allowing the freedom to position the pole and shear device. For this, a plain spherical bearing, Figure 7-6, was decided upon to allow for 360 degrees of rotational freedom as welli as its 12-degree of lateral motion. The telescoping pole would ride in the center of the bearing allowing the pole to be maneuvered. This freedom gives the device a 12' range of motion over the center of the tripod base. In addition, the bearingserves as a motion limit. The tipping and counter weight calculations were based on operating conditions, which are between 75 and 90 degrees from horizontal. The bearing prevents the operator from tilting the pole past an angle of 12 degrees from vertical and allowing the pole to fall. An added effect of the use of the bearing is that it prevents the operator from moving the pole too quickly due to its internal friction. 7-7 7.4.2 Design Components (Telescoping Tripod Legs) The device uses telescoping tripod legs to allow it use on uneven ground conditions while still maintaining the minimum tipping plain distance. These legs serve as two roles, the first to hold the pole and device while being used, and the second to allow the operator to adjust the height of the device for storage and transportation purposes. The casters located at the end of the two legs were selected for their ease of roll, and diameter. The ease of roll was an important issue to lighten the pulling force required to transport the entire assembly. The diameter chosen be large enough to be rolled over various obstacles found in the yard that may impede the motion of the tripod. 7.4.3 Design Components (Locking Device for Pole) The use of a manually actuated hydraulic cylinder requires that the operator use a hand to 'pump' the shears close and cut through the tree limb. Therefor the team felt that it was necessary that operator be able to lock the telescoping pole into place once it was positioned on the tree limb and move to a separate area where the hydraulic hand pump would be. By moving the operator away from the tripod, and the area of falling limbs, the operator not only does not have to be concernedwith the holding of the pole, but can be positioned in a safer area. To lock the telescoping pole into place there is a thumbscrew threaded into the side of the spherical plain bearing, Figure 7-6. The thumbscrew has a knurled head at its end, when turned, moves the end of the screw into the moving section of the bearing. A friction fit is caused between the bearing halves, immobilizing the tilting of the telescoping pole. Figure 7-6 Plain Spherical Bearing 7-8 7.5 Final Tripod Design The tripod consists of a plain spherical bearing with 12 degrees of lateral freedom, purchased from RBC Bearings, that is press fit into a base plate made of Aluminum 6061-T6 that will enclose the side wall of the bearing. The base plate is triangular with rounded tips. On the three flat surfaces of the base plate are three male linkage components that connect the legs to the base plate. The legs of the tripod aretelescoping poles, making the height adjustable for the operator. The legs are attached to the male link component through a female link component that will be pinned to the male link. The male and female links were design to limit the angle at which the legs could be open. At the end of two of the three legs are casters (See Figures 7-7 and 7 -8). The casters are for transportation purposes. It was determined that it would be more ergonomically correct to role the device than to carry it from storage location to the pruning location. A handle is also located on the base plate of the tripod for rolling purposes. This handle, as well as, the positioning handle has been designed with ergonomically considerations. The positioning handle is situated on base tube of the pole, which is used to position the shearing device next to the desired branch. Figure 7-6 Closed Tripod Assembly 7-9 Figure 7-7 Op en Tripod Assembly 7.6 Tripod Prototype Testing and Evaluation During the spring quarter the team manufactured and purchase parts necessary to build a prototype of the tripod. A 1/3 scale size pole was purchased from JTD enterprises due to the costs of manufacturing a full size pole, therefore the tripod was built to a 113 scale as well. Using aluminum 6061-T6, which was available in the schools machine shop, the tripod base plate and leg brackets were machined. The three telescoping legs and plain spherical bearing were purchased from the same supplier of the designed tripod but to a 113 scaled size. When the ordered parts were received and the machined parts were finished the tripod was assembled. The tripod was tested for tipping by adding a scaled weight to the end of the telescoping pole. The telescoping pole was fully extended and tilted to 12 degrees from vertical. The pole was then placed at the worst case tipping area, which is half way between any two legs. It was found that the scaled tripod and pole assembly did not require the team to add a counter balance weight; due to the differences in material between the calculated carbon fiber pole and the aluminum model pole. The assembly 7-10 model was maneuvered and positioned simulating the actions the operator would apply. The team found that the assembly did not have the tendency to tip. These physical tests were preformed to verify that the analysis of the tripod design was. The prototype verifies the design and that the tripod will support the pole and shearing device reducing the forces required by the operator to prune trees. Figure 7-8 is a picture of the scaled tripod and telescoping pole. Figure 7-8 Tripod & Telescoping Pole Assembly 7-11 8. Conclusion The following is a conclusion to the capstone project, Design of a Tree Pruning Device. It represents work compiled from the winter and spring quarters of 1999. It covers the following issues: • The reasons why waterjet technology is not feasible • Effective cutting diameter • The conceptual design of the shear mechanism and sleeve • The conceptual design of the extension pole and collet locking mechanisms • Methodology for proltotyping the pole • Interaction between the extension pole and operator • The development of the tripod assembly • The experiments to be performed next quarter 8.1 Waterjet Concept Elimination After researching waterjet-cutting mechanics, the relationship of working pressure verses cutting time of a three-inch diameter branch was correlated. The analysis assumed that the waterjet stream was precisely guided along the cutting path varying the feed rate according to the depth of cut to maximize cutting efficiency. To minimize the cutting time, a device would have to adjust the feed rate depending on the depth of cut and the material properties of the wood being cut. Material properties of wood vary greatly between species of tree and the condition of the wood. Developing a device capable of controlling feed rate would be difficult to design, and add significant weight to the pruner. An electronically controlled device would be unreliable and add significant cost. A mechanical mechanism that senses branch diameter would still require user adjustment for wood type and condition. Most homeowners are not familiar about the compressive strength of tree species and wood condition .. A mechanism that has a constant or non-adj ustable feed rate would be inefficient cutting small branches. To overcome this problem, the working pressure would have to be 8-1 significantly higher than the worst case scenario to cut the wood in a reasonable amount of time regardless of matetial properties and cutting diameter. The minimum pressure needed to cut the branch within one minute was calculated to be 25,000 psi. Typical consumer and professional power washers have a maximum operating pressure of about 5,000 psi. To increase the pressure of these types of devices requires the use of a pressure intensifier. Industrial intensifiers are used on large, stationary machines that use waterjet cutters. The cost of these intensifiers range in tens of thousands of dollars. Portable intensifiers with the required pressure boost ratio are not available and an intensifier would have to be designed for our goals. Designing an intensifier to meet our needs is not a practical solution. The cost to produce an acceptable device would breech our goal to maintain an affordable product for most professional and consumer markets. Designing an acceptable intensifier that would follow the proper pressure vessel codes for safety would require more time and resources than allotted for our project. The most significant reason for not attempting to develop an intensifier for a pruning device is safety. When dealing with pressures of that magnitude, the safety of the operator and any surrounding bystanders would be compromised. This design liability is not acceptable and justifies our decision for eliminating the waterjet concept. 8.2 Shear Cutter Concept Concerns of feasibility of the initially proposed waterjet concept were raised prior to our decision to eliminate the waterjet concept. As a precaution, alternative concepts based on current pruner designs were generated. The shearing concept was chosen from our selection of design solutions and researched in parallel with waterjet cutting technology. Literature of shear cutting mechanics was ordered for determining cutting force requirements analytically. While waiting for receipt of the literature, an attempt to model the mechanisms of woodcutting using known failure theories was unsuccessful. Expert consultation confirmed our inability to accurately model woodcutting mechanisms due to unknown failure mechanisms specific to woodcutting. Physical testing of similar devices 8-2 was received during the literature search, and used to estimate force requirements using a different approach. Extrapolation of the physical data also proved to be inaccurate for design purposes, and it was decided that physical testing of a device capable of cutting three inch diameter branches was necessary. A bypass shear cutter from Corona® Clipper was ordered to do the physical testing and is actually used for our proof of concept prototype. Fixtures were designed for the Instron machine to test the bypass blades cutting force. Physical testing of the bypass shears was done and force requirements were generated. The results of the physical tests were used to finalize pole analysis, material selection and power generation. The recommended concept uses a hydraulic piston in line with a hydraulic hand pump to generate the cutting force. The piston and shear assembly is partially contained inside of a square sleeve to eliminate any moments that could be transferred to the pole. Through a series of linkages, the piston is attached to the bypass blades. The bypass blades had to have extension arms pressed fit and bolted onto them to secure the linkage design. This was a difficult task because the shears could not be machined or welded due to the heat treatment of the shears. Extensive calculations were done on all of the linkages to ensure a factor of safety of three on all components. The prototype was then built and tested. The prototype was successful in cutting tree branches with a diameter of three inches. A pressure gauge was installed in line with the hand pump. This was to ensure that our calculations were correct. The pressure gauge measured a maximum pressure of 1600 psi for a three-inch diameter maple branch. This was only 100 psi above the predicted value of 1500 psi for a dead maple branch. This shows that the force requirements calculated from the physical testing is accurate. An additional feature added to the prototype allows for automatic opening of the shear blades after cutting. The back port of the piston is capped allowing the piston to open when the release valve is opened on the hand pump, thus opening the shear blades. 8.3 Pole User Interactions From the start of this design project, the design of the pole has been independent to the design of the pruning mechanism. The pole requirements are 8-3 • To have a 25ft reach • To be lightweight • To have a non-conducting interface • To have a static deflection of less than 6 inches. To achieve a reach of 25ft, the idea of a telescoping pole was implemented. The telescoping pole allows the device to be operated at varying heights. The pole weight and deflection are a function of the material selection. The material needs to have a low density to have a low weight. The deflection of the pole is dependent to the Modulus of Elasticity of the material, therefore a material with a high Modulus of Elasticity is desired. The material selected for the design was Thome!® Carbon Fiber. The 3 Thomel® Carbon Fiber has a low density of .074 lbmlin , and a Modulus of Elasticity of 6 120x10 psi. Based on the static calculations of a telescoping extension pole, the design methodology for the pole is complete. The material used for the calculations was Thome!® Carbon Fiber, but the methodology is the same for any material used. The weight of the pruning device and pole has been limited to 25lbs. The current use of Thomel® Carbon Fiber causes the weight of the pole to be approximately 22 lbs., which introduces the use of a tripod. The static deflections calculations revealed that the pole would statically deflect 1.0151 inch, which is less than the required 6 inch. Modeling the pruning device and pole as a spring-mass damper system, the dynamic analysis of the pole was completed to reveal a response that was unfavorable for quick motion of the pole. The design for the telescoping extension pole has eight sections, where the base section has an outer diameter of 3.5 inches and a wall thickness of .125 inch. Every extension section there after has varying wall thickness as the pole sections extend, but the outer diameter reduces complying with the physics of a telescoping pole. The length of the first section is 44 inches, the next four sections is 48 inches each with the last three sections having a length of only 40 inches. Between each section of the telescoping pole will be a collet. The collet is an external locking device, which locks the device into position and increases the dexterity of the pole for the user. 8-4 The shear device will be affixed to a hollow sleeve, which fastens to the pole at the last extension section. The sleeve will be designed in a way, which will reduce any additional forces the shear may apply to the pole. In addition to the sleeve, the handle in which the operator holds the pole can be designed to eliminate most of the additional forces from the shear device. The positioning of the pole during operation is related to the user ease of use and has not yet been determined. Whichever position decided on for the pole during operation, the location of the ergonomic handle wiH be consistent. The ergonomic placement of the handles is at the waist of the user. The handles will be design to have a power grip to lessen the effects the weight of the device. The design of the handles will also include the effects of any additional stress from the shearing device. In additional to the dynamic testing of the pole, testing the additional forces from the shear mechanism is planned for next quarter to determine the effects that the shear mechanism will have on the pole. A vendor was found to purchase a 1/3 scaled model of the telescoping pole. The prototype allowed us to show a proof of concept for the telescoping pole. The 1/3 scaled model included the correct number of sections, the same concept of rotating locking collets, internal instead of external, where the over all length pole and the OD of the base tube were at a one third scale. 8.4 Tripod Assembly Once the weights for the telescoping pole and shearing device were finalized, the force to carry, hold and maneuver the pole could be calculated. The overall weight of 27.6 lbs. was not a concern for the operator to cany, being an acceptable weight. However, when the telescoping pole is extended to the full length and titled at an angle less then vertical, the forces that the operator must apply to keep the pole from tipping further are large. The operator would hold the telescoping pole to their side with their hands approximately 2.5 feet apart in a postulated grip. At only 15 degrees from vertical the operator would have to apply close to 40 lbs. of force with their forward most hand while supporting the over all weight of the assembly, 28 lbs., with their other hand. The magnitude of these forces is not acceptable for extended periods. 8-5 It was determined that the maximum acceptable tilt from vertical for the telescoping pole would be 15 degrees. At this angle, the base of the tripod will be 6.5 feet away from the cutting devise and subsequently the falling tree limb. By using 15 degrees it was determined that a counter balance weight of 25 lbs. added to the end of the telescoping pole would reduce the operator input to 25 lbs. of force. By using, that same counter balance weight the tipping plane was reduced to a distance of 14 inches from the center of the tripod. Taking a marginal factor of safety, the team decided on using 21 inches, which correlated to ends of the tripod legs being 6 feet apart. The team felt that this distance was appropriate for the operator to walk between and maneuver the telescoping pole, while not being so large that it would be difficult to set up in a small area. This entire device could then be maneuvered by the operator applying 42 lbs. of force during transportation. The tripod consists of a plain spherical bearing with 12 degrees of lateral freedom, purchased from RBC Bearings, that is press fit into a base plate made of Aluminum 6061-T6 that will enclose the side wall of the bearing. The base plate is triangular with rounded tips. On the three flat surfaces of the base plate are three male linkage components that connect the legs to the base plate. The legs of the tripod are telescoping poles, making the height adjustable for the operator. The llegs are attached to the male link component through a female link component that will be pinned to the male link. The male and female links were design to limit the angle at which the legs could be open. At the end of two of the three legs are casters. The casters are for transportation purposes. It was determined that it would be more ergonomically correct to role the device than to carry it from storage location to the pruning location. A handle is also located on the base plate of the tripod for rolling purposes. This handle, as well as, the positioning handle has been designed with ergonomically considerations. The positioning handle is situated on base tube of the pole, which is used to position the shearing device next to the desired branch. 8-6 8.5 Summary The proof of concept prototype and the desired design of the shear assembly could have been modified so that it was smaller and lighter. Even with these changes, the design would still have trouble competing in the market today. Although our device can cut through three-inch diameter branches that are 25 feet above the ground safer than most devices. Excessive weight, cost, and potential difficulty of operation do not allow our device to compete as a marketable product to a homeowner. 8-7 References General Information Ullman, David G., The Mechanical Design Proces��. 2nd Edition, McGraw-Hill, Inc., 1997. How to Prune Trees, Peter J. Bedker, www.aggie-horticulture.tamu.edu/extension/pruning/pruning.html Follow Proper Pruning Techniques, www. greenindustry.corn!AA /current/299saw .htm www. ag. ui uc.edu/ni sal arbnews/feb98/feature2.htrr! Waterjet Technology Books: d Munson, Bruce R., Fundamentals of Fluid Mechanics, 2n Edition, John Wiley & Sons, Inc., 1994. Tikhomirov, R. A., High-Pressure Jetcutting, American Society of Mechanical Engineers Press, New York, 1992. Web-sites: Abrasives used in Waterjeting, www.Claymore.engineer.gvsu.edu/-jackh/eod/manufact/abrasive/abrasive.htm Ingersoll-Rand Products, www .irautomation.com/waterjet/index/html Waterjet, www .marshalsea.co. uk/hi2000a.html Grand Valley, www .claymore.engineer.gvsu.edu/-tumer c/basics.htm Waterjet Accessories, www.richel.com/artwjsus.html Waterjet Information, www .jobshop.com/techinfo/papers/waterjet.html Catalog: Lechler, Industrial Spray Nozzles, Systems and Accessories Catalog #140, page 48,49 Pressure Washer Web-sites: Hotsy Pressure washer Products, www.hotsy.com/products.htm Sears Lawn and Garden Products, www .Sears.corn!craftsmanllawn garden/index.htm Telescoping Extension Poles Books: Callister, W. D. Jr., Materials Science and Engirteering, An Introductioq, 4th Edition, John Wiley & Sons,, Inc., 1997. nd Beer, Ferdinand P. and Johnston, Russell E., Mechanics of Materials, 2 Edition, McGraw-Hill, Inc., 1992. Spoutts, M.F., Design of Machine Elements, 7th Edition, Prentice Hall, Upper Saddle River, New Jersey, 1998. Web-sites: Testrite Supplies, www.Testrite.com/telescoping.:!!Jbes/products-guide.html Trailblazer Products Site, www .Trailblazersproclucts.com/products/xtpole.htm Treasure Valley Supply Co, . www.Treasureva1ls:y!mpply.com/stec09.html Pole by Mrlongarm, www.Mrlongarm.com/poles.html Cutting Edge Technology Parish, R.L., "Operating Force Requirements for Manual Pruning Shears"; Applied Engineering in Agriculture; Vol. 14; pp. 349-352. Web-sites: Fred Marven Associates, www.pruner.com/diagrams.html HusqvarnaCatalogue, www2.husqvarna.com/husqvarna/catalog/purner.html Fiskars Products Guide, fi skars.com/gardener�ningstik/feather.html Garden Products Guide, www.gardeners.com/gardeners/-3 1-330.htm1 Hand Powered Hydraulic Poles, www.nsteP.:.!letlezprune/prune/main.htm Specialty Pruners, www .europa.com/-pachar/PR UNE/Pruner.htm Hydaulictools, www .newdraulictools.com Welcome to the Gilmour Group, www.gilmour.com/snapcut/snapcut.shtml Fiskars Garden center, www.fiskars.com/gardeners/for gardeners.html Saw Devices Web-sites: Kensama Power Pruner, www.nb.net/-kensma/power pruner.html Coronaclippers Catalog,_:�:.!yw.coronaclipper.com/catalog.htm Uniontools, www .ir. uniontools.com/ut/newdev/R BRachet.html Safety Aspects Pheasant, Stephen, Ergonomics, Work and Health, Aspen Pub. Inc., 1991. Web-sites: Consumers Product Safety Committee, www.cpsc.gov/70/00/cpsc.pubs/tools/soll.htm Patent Searches Web-sites: United States Patents Search www.uspto.gov "Telescoping Hacksaw Frame", DeCarolis, et al., US Patent 5,044,083, Sept. 3, 1991. "Chain Saw Cutter Bar and Safety Guard"; Greene, et aL; US Patent 5,269,064; Dec. 14, 1993. "Abrasive Formulation for Waterjet Cutting and Method Employing Same"; Chopra, et al.; US Patent 5,637,030; June 10, 1997. "Water Jet Mixing Tubes Used in Water Jet Cutting Devices and Method of Preparation Thereof'; Banholzer, et al.; US Patent 5,363,556; Nov. 15, 1994. "Two Stage waterjet and abrasive jet catcher"; Hashish, Mohammed A.; US 1905000796424; Nov. 8, 1985. "Quick Assembly Waterjet Nozzle"; Munoz, Jose P.; US Patent 5,794,858; Aug. 18, 1998. "Waterjet Orifice Assembly"; Wands, et al.; US Patent 5,848,753; Dec. 15,1998. "Intensifier"; Boers, et al.; US Patent 5,092,744; March 3,1992. "Tree Trimmer"; Massa, Robert E.; US Patent 5,826,34 1; Oct. 27, 1998. "Cutting Shears Particularly Secateurs"; Auderset, Regis; US Patent 5,757,589; Aug. 4 1998. "High Branch Pruning Shears Structure"; Lin, Clm-Lan; US Patent 5,634,276; June 3, 1997. * All web-sites are current as of 1/25/1999 Appendix A Patents TTnited States Patent: 5,826,341 http:!/1 64. 195.1 00. 1 1/netacgi/nph-Parser... 82634 1 ' .WKU.&OS=PN/582634 1 &RS=PN/58263' - ( 1 of 1 ) United States Patent 5, 826,341 Massa October 27, 1998 Tree trimmer Abstract A portable tree trimming device comprising a pruning mechanism secured at a distal end of a telescopically extendible housing. The pruning mechanism includes cutting members exterior of the housing drivable by a motor within the housing. The motor receives current furnished thru a coiled cable within the housing receiving power from either a domestic electric source or from a battery unit positioned within the housing. The coiled cable extends and protracts in unison with extension and protraction of the extendible housing. Inventors: Massa; Robert E. (312 E. 48th St., Tulsa, OK 74105--4514) Appl. No.: 890012 Filed: July 10, 1997 U.S. Class: 30/247; 30/249; 30/296.1 Intern'! Class: B26B 015/00 Field of Search: 38/247,249,245,228,296.1 Referemces Cited [Referencedl!Yl U.S. Patent Documents 1 of 10 6/1/99 11:08 PM 11'1ited States Patent: 5,826,341 http:// l64.195.1 OO. l llnetacgi/nph-Parser...82634 1 ' .WKU.&OS=PN/5826341 &RS=PN/58263" 1762392 Jun., 1930 Gray 30/247. 2504405 Apr., 1950 Fletcher 30/249. 2600540 Jun., 1952 Johnson 30/249. 27 14250 Aug., 1955 Twedt 30/249. 2731721 Jan., 1956 Traurig 30/247. 3178816 Apr., 1965 Schmid 30/247. 3657813 Apr., 1972 Knight 30/296. 4574481 Mar., 1986 Ericsson 30/296. 4696108 Sep., 1987 Zerrer et aL 30/296. 4760646 Aug., 1988 Siegler 30/382. 4924573 May., 1990 Huddleston et al. 30/296. 4976031 Dec., 1990 Miller 30/296. 5367773 Nov., 1994 Robbins 30/228. PrimaryEx aminer: Payer; Hwei-Siu Attorney, Agent or Finn: Massa; Robert E. Claims 1. A tree trimmer, comprising: an elongated tubular housing, a pruning mechanism mounted on a first end of the tubular housing, including a first cutting member fixedly secured on the tubular housing, and a second cutting member pivotally secured on the first cutting member and in cutting cooperation with the first cutting member, an operating component positioned within the tubular housing adjacent to and connected to the pruning mechanism, the operating component including a motor, and a clutch, a driving component positioned within the tubular housing connecting the operating component to the pruning mechanism, and a power cable component positioned within the tubular housing connecting the motor to a source of power with said power cable component further connected circuitably to a power switch positioned near a second end of the tubular housing. 2 of 10 611199 11:08 PI\ l l>Jited States Patent: 5,826,341 http:/1164. 195.1 OO. l llnetacgi/nph-Parser... 82634 1 ' .WKU.&OS=PN/5826341 &RS=PN/58263 2. A tree trimmer as described in claim 1, wherein said tubular housing includes two telescopically extendible tubular members forming said tubular housing, and said power cable component comprises a coiled cable member, whereby the coiled cable is adaptable to extend in uncoilable length as the tubular housing is extended, and contract in coilable length as the tubular housing is contracted, yet will remain within the tubular housing. 3. A tree trimmer as described in claim 2 wherein the driving component includes a gear mechanism, and a connecting member connecting the gear mechanism to the second cutting member. 4 .. A tree trimmer as described in claim 3, wherein substantially all of said components are positioned within the tubular housing. 5 .. A tree trimmer as described in claim 4, wherein the first cutting member has an arcuate cutting edge to provide more secure cutting positioning, and the second cutting member has an arcuate cutting edge. 6. A tree trimmer as described in claim 5, wherein said tubular members comprise an upper tubular member and an adjacent lower tubular member, said upper tubular member having an interior diameter smaller than thalt of said adjacent lower tubular member. 7 .. A tree trimmer as described in claim 6, wherein the source of power comprises a domestic power source. 8. A tree trimmer as described in claim 7, wherein the tubular housing is made of non-metallic material. 9. A tree trimmer as describedin claim 6, wherein the source of power comprises a portable battery component. 10. A tree trimmer as described in claim 9, wherein the tubular housing is made of non-metallic material. Description 3 of 10 611/99 11:08 p� TT'lited States Patent: 5,826,341 http:l!164. 195.1 OO. l l/netacgi/nph-Parser ...82634 1 ' .WKU .&OS=PN/5826341 &RS=PN/58263· FIELD OF THE INVENTION My invention relates to tree trimming devices. More particularly, my invention relates to electrically powered tree trimming devices. More particularly, my invention relates to portable, electrically powered tree trimming devices which may be telescopically extendible to reach tree limbs or branches at different heights. Still more particularly, my invention relates to tree trimming devices having a cutting component on a distal end of an extendible base member with the cutting component actuable by power transmitted through a coiled cable within the base member. BACKGROUND OF THEINVENTION Many tree trimming devices have been designed for pruning small branches from trees. Generally, tree trimming devices have been composed of cutting devices positioned atop extendible rods or poles in order to reach considerable distances through a small tree. The various tree trimming devices have been either manually operable or power-driven. For power-driven tree trimming devices, the source of the power has been either hydraulic, gasoline, or electric. The type of cutting mechanism for cutting small branches may be either some form of shear apparatus or saw type device, which may even be a saw blade or chain saw member. I have owned and used a particular type of manually-operated tree trimming device for many years, and consequently have become aware of certain disadvantages which I felt could be improved. The tree trimming device which I have used comprises an extendible tubular member having a lever operable cutting component at the distal end. The lever device extends radially from the tubular member. A long cord is attached to the leverable end of the cutting component, and the cord is longer than the tubular member to be grasped by the operator for activation. Then, a strong pull on the cord operates the cutting component. I have encountered several distinct disadvantages in the use of my manually-operable tree trimming device. For example: a. The manual trimmer requiresa long, manipulating cord which extends loosely from the cutting component at the upper, distal end of the long tubular support member to the lower end of the tubular support member held by the operator. The lever operating the cutting component extends a considerable distance radially from the support member, and consequently the cord is held at a distance radially from the axis of the support member from the top of the support member to the lower end of the support member. Consequently, the cord very easily becomes entangled with many small tree branches as I try to maneuver the tree trimmer into suitable position among the many tree branches. b. The long, loose cord which operates the operating lever component requires the operator to grasp the cord firmly and pull with considerable forct:� to sever the particular tree branch currently positioned within the cutting member. I estimate that each cutting action requires an armmovement of at least 2.5 to 3.0 feet to operate the cutting component because of the leverage built into the manual action of the device. Even though the operating component is constructed with considerable leverage, a strong pull is required and the operator's arm may soon become quite tired, and possibly even unduly injured if not handled with care. c. The manual trimmer, with all the components operating exteriorly of the device, requires a great deal of 4 of 10 611199 1 J :08 Pl\ Hnited States Patent: 5,826,341 http:l/ 1 64. 195.100. 1 1/netacgi/nph-Parser. ..82634 1 ' .WKU.&OS=PN/582634 1 &RS=PN/58263L attention applied to the maneuvering and positioning of the cutting components, levers, and manipulating cord. I found that the attention given to the operating components detracts from important attention which should be given to the careful positioning of the operating component when there are power lines passing through or adjacent the tree which is being trimmed. Thus, in considering the possible manner in which a tree trimming device might be improved, I eventually developed the invention which I describe herein. In accordance with the usual practice, I have conducted a patent search which revealed the following patents which were considered to be the closest to my invention: u.s. Pat . No . 1,762,392 Gray June 10, 1930 u.s. Pat . No . 2,714,250 Twedt Aug . 2, 1955 u.s. Pat . No . 2' 731, 721 Traurig Jan . 24, 1956 u.s. Pat . No . 3,178, 816 Schmid April 20' 1965 u.s. Pat . No . 4,760, 646 Siegler Aug . 2' 1988 u.s. Pat . No . 5,367,773 Robbins Nov . 29, 1994 U.S. Pat. No. 1,762,392 to Gray describes a portable, hand-held, motor-operated shearing device. It is intended to provide a shear which may be used for shearing heavy material, such as tin or sheet iron. The device is used to make curved cuts of small radii. U.S. Pat. No. 2,714,250 to Twedt describes a hydraulic pruning tool comprising an elongated hollow tube containing an upper piston connected to the cutting head and the upper piston connected to a lower piston to which is attached an actuating lever which operates a self-contained, manually-operated pump. U.S. Pat. No. 2,731,721 to Traurig describes power operated shears in which the cutting stroke may be adjusted in order to provide either a completely closed cutting stroke or a partly closed stroke. For shearing during continuous action of the shears, it is more efficient to keep the shears from closing completely during each stroke. The housing includes a motor for driving the shears, and the shears comprises a stationary lower blade and a driven upper blade. Thus, the amount of closure of the blades is adjusted by the adjustment of the angle of inclination of the stationary lower blade. The angle of inclination may be adjusted by an adjusting mechanism connected to the stationary blade at a point within the housing and adjustable from outside the housing. U.S. Pat. No. 3,178,816 to Schmid describes a motor driven pruning shear in which the operation is such that the motor rotation is reversed with each cycle of the shear. A casing includes the motor, a drive screw connected to the motor and to an electric switch device within the casing. The shear includes an upwardly projecting fixed shear blade mounted on the casing, and a movable blade pivotally connected to the fixed blade. The movable blade is attached to the screw mechanism. With each cycle the screw mechanism causes a lug to move into contact with the switch to reverse the action of the motor. Also, a single action of the shearing blade may be achieved by a momentary squeeze of the trigger. U.S. Pat. No. 4,760,646 to Siegler describes a tree pruner and hedge trimmer operable either by manual 5 of IO 611199 11:08 PM Tlnited States Patent: 5,826,341 http:!/ 164.195.1 OO. l l!netacgi/nph-Parser...826341 '.WKU.&OS=PN/582634 1 &RS=PN/58263' power, a gasoline engine, or an electric motor. The basic components for all sources of power are essentially the same. The apparatus includes an elongated telescopic boom having a cutting assembly at the top with the power means at the bottom. The pruner embodiment includes a chain saw in the cutting assembly. The hedge trimmer consists of a cutting blade. The cutting assembly of the chain saw includes means for infinitesimal adjustment of the chain saw, and the chain saw assembly is designed to eliminate kickback of the chain saw. Intermittent rotary motion is given to the chain saw or hedge trimmer disc by means of a pulling force produced by either the power source or manual operation. The manual embodiment provides sufficient force to operate the cutting member only by the provision of a longer manual power stroke and longer rewind spring. U.S. Pat. No. 5,367,773 to Robbins describes a power drivenpruning device comprising an elongated support member having a cutting member at the upper end and an actuating member at the lower end. The cutting member includes a stationary cutting component secured to the end of the support member and a pivotal cutting component attached to the stationary component. The pivotal component includes an elongated portion to provide leverable action to the cutting member. The drive member includes a spool for storage of a cable which connects the drive member to the elongated portion of the pivotal cutting component to transmit suitable force to the cutting component. A tension spring connects the pivotal cutting component to the stationary cutting component to give the device a resilient action. SUMMARYOF THE INVENTION The primary object of my invention is to provide a tree trimming device which is simple in construction, efficient in operation, and safe to use. Another object of my invention is to provide a tree trimming device which is convenient to use, easy to handle in avoiding entanglement with tree branches which it is not intended to cut, and easily maneuverable. Still another object of my invention is to provide a tree trimmer which is easily adjustable for trimming branches at various heights within the tree. Still another object of my invention is to provide a tree trimmer which is adaptable for trimming tree branches which are at considerable distances from the ground. Still another object of my invention is to provide a tree trimmer which is electrically operable in a smooth and safe manner. Still another object of my invention is to provide a tree trimmer which includes an electrical power component which operates the trimming device in a safe and convenient manner. Still another object of my invention is to provide a tree trimmer which is portable and is therewith efficiently and safely operable. Although it would be theoretically possible to construct tree trimming devices capable of cutting large diameter branches, it would not be considered practical or safe for an inexperienced gardener to employ extremely heavy duty tree trimming devices .. For instance, large diameter branches, such as 2 to 3 inch diameter branches, would inevitably comprise a great deal of wood and be extremely heavy and would require heavy equipment and would be dangerous activity. It would be very dangerous for the average household gardener to try to trim branches of great 6of 10 6/1/99 11:08 Piv' T T"lited States Patent: 5,826,341 http:l/1 64. 195.1 00. 1 1/nctacgi/nph-Parser... 82634 1 '.W KU.&OS=PN/582634 1 &RS=PN/58263' weight. These should be reserved for the professional tree pruner. I have considered safety to the operator as of primary importance with the design of my tree trimming device. Therefore, I have purposely designed and built a light-weight, portable tree trimming apparatus to be easily maneuverable by the average home gardener. I have particularly eliminated the commonly-used, exteriorly-positioned operating ropes, wires or cables, and awkward operating components in order that the operator may devote his entire attention to the guidance of the operating head of his tree trimmer and not have his attention constantly diverted to extensive exterior components of his trimmer. The coiled electric line of my tree trimmer is of a length sufficient to extend beyond the length of the trimmer shaft when the telescopically extendible shaft is extended to the fullest length. With the coiled wire there will be no twisting or curling within the tubular shaft members as the shaft is extended to its full length or shortened to its shortest length for storage, as there would be in the use of a non-coiled wire. A further arrangement to prevent any entanglement of the transmission wire, or to prevent excessive wear of the wire, is to configure the tubular components of the shaft in a manner, preferably, that a tube member of smaller diameter is successively positioned toward the distal end of the trimmer. Thus, the ultimate tube member upon which the operating components placed is of the smallest diameter, and as a result there will be much less opportunity for excessive wear of the wire member as the tubular components are retracted for storage or adjustment. The electric switch provided may be either a momentary switch or continuous action. For thin, soft branches, a single action of the cutting blade should be preferable, and for thicker, tougher branches, a continual action of the cutting blade should be preferred, thus allowing the operator to maintain the action until the tougher wood is cut. I have designed my tree trimmingapparatus with all possible consideration for safety regarding electrical reactions. Any time a long pole is maneuvered through the branches of a tree, there is a chance for unwitting contact with an electricline. In addition, without careful observation, a tree trimmer might even contact branches which appear to be safely removed from power lines, but actually are in contact with some power lines which become exposed through removal of insulation. In such instances, older power lines might have open, uninsulated areas which might be occasionally in contact with some branches, especially aftera rain, when both lines and branches are still wet. Thus, the tubular components should preferably be of non-conducting plastic material, certainly not of metal. My tree trimming device may be operable either by means of connection to a typical domestic electrical power source, or by inclusion of a battery component. Attachment to a domestic power source may be readily accomplished by the conventional extension cord. A battery-powered tree trimming device may be powered by inclusion of a conventional re-chargeable battery. In my tree trimming device I have made the lower cutting blade of the cutting component movable and operable leverably by the actuating assembly in order to provide the greatest amount of force for the cutting operation. The coiled configuration of the electric wire will assure, that upon extension or contraction of the tubular members, there will not be undue rubbing of any of the coiled wire against an inner rim of a tubular 7 of 10 611199 11:08 Pl\' T T'lited States Patent: 5,826,341 http:/1164. 195.1 00. 1 1/netacgi/nph-Parser. ..82634 1 ' .W KU .&OS=PN/582634 1 &RS=PN/58263- member; the careful choice of proper coiled wire members will avoid this action. An electric cord which is not properly coiled will not provide for easy extension or protraction of the cord eventual damage or entanglement of the cord. I shall subsequently describe in detail other major features of my tree trimming device. Then, the above objects and advantages of my invention will become apparent from my description of the following preferred embodiments of my invention . BRIEF DESCRIPTION OF THEDRAWINGS FIG. 1 is an exploded side view of a tree trimmer device according to my invention showing the tree trimmer as it would be in a retracted condition. FIG. 2 is an exploded side view, partly in section, of one embodiment of a tree trimmer device according to my invention illustrating interior positioning of operating components as the device would appear in a retracted position. HG. 3 is an exploded side view, partly in section, of the embodiment of tree trimmer device shown in FIG. 2, illustrating a device as it would appear in :an extended position. HG. 4 is a sectional view of operating components of a tree trimming device according to my invention. FIG. 5 is a top view of a tree trimming device according to my invention. HG. 6 is an exploded side view, partly in section, of an alternate embodiment of a tree trimmer device according to my invention, describing a battery-operated embodiment in a substantially extended condition. DESCRIPTION OF THEPREFERRED EMBODIMENTS In FIG. 1, I describe one embodiment of a tree trimmer device 10, generally, according to my invention. In the elevational view of FIG. 1, I describe the tree trimmer 10 as having housing members 12, 14, and 16 fitted together in a retracted condition, as it would be considered in its most convenient position for ease of handling or easy storage. The tree trimmer device 10 includes a cutting component 38, generally, positioned securely upon an upper, or distal, end of the trimmer, thus positioned upon housing member 12. FIG. 1 also shows one manner in which the housing members 12, 14, and 16 are held in position by clamping members. A first clamping member 20, generally, includes a securing band 22 around housing member 14 and held in suitable adjustment and security by means of a thumb screw 24. Housing member 14 may be suitably positioned within housing member 16, and held securely therein, by means of a second clamping member, 26, generally, which includes a securing band 28 around housing member 16 and held in position by a thumb screw 30. For storage, or easy transportation, the tree trimmer may be easily handled by loosening of thumb screws 24 and 30 and retraction of housing members 12 and 14 into housing member 16. Then, for operation, the housing members may be suitably adjusted and secured into position as preferred by the operator. 8 of 10 6/l/99 1 :08 p Tlnited States Patent: 5,826,341 http:/1164. 195.1 OO. l l/netacgi/nph-Parser. .. 82634 1'.WKU.& OS=PN/5826341 &RS=PN/58263" A handle member 32, generally, comprises a securing band 34 securable into comfortable position by adjustment of a screw-type handle member 36, adjustable by the operator. As I have described above, and now show specifically, in FIGS. 1 and 2, I have designed a tree trimmer which is safe, convenient, and easy to use, because I have eliminated undue interference which is commonly noted in extendible tree trimming devices, which is particularly encountered because of components of such devices which extend substantially radially from a tubular component. The method of handling is made easier because more attention may be given to the maneuvering of the tree trimming device and less attention need be given to loose exterior components. My tree trimmer device 10 includes a pruning component 38, generally, positioned at the distal end of the t1immer, and which includes a stationary cutting member 40 attached to a support member 42 by any suitable means of attachment, such as a screw 44. The pruning component 38 includes a movable cutting member 46 which has a sharp cutting surface 48. Cutting member 46 is movably secured to the stationary cutting member 40 by means of a pin 50. Then, for cutting operation, movable cutting member 46 is operatively connected by means of a pin 52 to a flat bar member 54, which, in tum, is connected by pin 56 to a gear component 58, which is operatively positionable against driving gear 60. Driving gear 60 is positioned on shaft 62 connected to a conventional clutch component 64, generally, of a type of clutch conventionally used for power equipment to permit safe and protective operation. The clutch component 64 provides the means for quickly and safely disconnecting the cutting components from typical electric motor 66 should there be a sudden interference of the cutting action by any sudden overload of the motor, as when the cutting member encounters a branch which might be too difficult to cut, or if the tree trimmer should encounter some other impenetrable object. Motor 66 is of a type commonly adaptable for use in the usual domestic type appliance or equipment, readily operable through the use of a safe extension cord. A most important feature of the tree trimmer device 10 is the use of a coiled cable wire 68, shown in FIG. 2 in a retracted condition, when the housing members 12, 14, and 16 are in a retracted condition; and shown in FIGS. 3 and 6 in an extended condition when the housing member 12, 14, and 16 are in an extended condition. At its upper end, wires of the cable 68 are attached to motor 66, and at its lower end, wires of cable 68 are attached to a switch member 70. The tree trimmer devices described in FIGS. 1, 2, and 3 show the switch member 70 connected by lines 72A and 72B to extension cord 74. In FIG. 6, lines 72A and 72B connect switch member 70 to a battery component (not shown) within the lower end of lower housing member 16. FIG. 6 describes a slightly modified power transfer component for the cutting mechanism. The means for transferring power from the gear component 58 to the movable cutting member 46 comprises a flat bar member 76, generally, which includes a slotted end member 78 enclosing pin 56 attached to gear 58, thus displaying another well-known form of power transmission. As I show in FIG. 4, the gear mechanism 58 is secured upon a shaft component 80 which is held rotatably and supportably within a bushing component 82 secured against the inner wall of upper housing member 12. 9 of 10 611/99 11:08 PM TT'lited States Patent: 5,826,341 http://l64.195.1 OO. l l!netacgi/nph-Parser...82634 1'.WKU.&OS =PN/582634 1 &RS=PN/58263 Since many different embodiments of my invention may be made without departing from the spirit and scope thereof, it is to be understood that the specific embodiments described in detail herein are not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims. ***** - 10 of 10 611/99 11:08 PJV l T'1ited States Patent: 5,634,276 http:/1 164.195.1OO. l l/netacgi/nph-Parser...634276' .WKU .&OS=PN/5634276&RS=PN/56342. - ( 1 of 1 ) United States Patent 5,634,276 Lin June 3, 1997 ------High branch pruning shears structure Abstract The invention herein relates to kind of improved structure high branch pruning shears that is structurally comprised mainly of the shears, a convex blade, a pull rod, an adjustment rod, a handle mount, a saw blade, and a pull rope. The handle mount is installed at the lower end of the shears and at the lower section of the handle mount is a roller wheel ensconced in an U-shaped component. The convex blade is hinged to the shears and is supported in operation by the concave blade. There is a fastening pin on the concave blade provided for the installation of the saw blade. One end of the aforesaid concave blade is utilized as a conjoinment and pivot point inside the slide slot of the pull rod and the front end of the pull rod is riveted to the shears with a recoil spring seated on the fastening rivet. One end of the pull role is guyed to the U-shaped component and then routed through the roller wheels of the handle mount and the adjustment rod, respectively, such that as the pull rope is dram downward, the adj ustment rod is subjected to a downward force that causes the movement of the pull rod and initiates the pivoting of the convex blade. When a coarse tree branch is encountered the adjustment rod slides into the next lower notch hole to achieve a greater shearing force and thereby effectively maximizes pruning efficiency, resulting in a pruning tool that requires minimum physical effort. Inventors: Lin; Chu-Lan (Changhua, TW) Assignee: Shang Gu Enterprise Co., Ltd. (Changhua, TW) Appl. No.: 442694 Filed: May 17, 1995 U.S. Class: 30/249; 301166.3 Intern'l Class: B26B 013/06 Field of Search: 30/166.3,146,244,245,246,249 References Cited [Referenced By] U.S. Patent Documents 1 of 7 61!199 11:10 P' T fTlited States Patent: 5,634,276 http:// 1 64. 195.1 OO. l l/netacgi/nph-Parser...634276' .WKU .&0S=PN/5634276&RS=PN/56342� 3360858 Jan., 1968 Cowley 30/249. 3835535 Sep., 1974 Robison et al. 30/249. 4760645 Aug., 1988 Davis 30/249. 497603 1 Dec., 1990 Miller 30/166. 5241752 Sep., 1993 Lutzke et al. 30/249. Primary Examiner: Payer; Hwei-Siu Attorney, Agent or Firm: Beveridge, DeGrandi, Weilacher & Young, L.L.P. Claims 1. An improved pruning apparatus, comprising: a first member having a concave blade portion and a handle portion:, a second member having a convex blade portion, an intermediate portion, and an extended portion, said intermediate portion of said second member being pivotally mounted to said first member; a pull rod having a slide slot and an adjustment slot defined therethrough, an end of said pull rod being pivotally mounted to said first member and said extended portion of said second member being slidably joined to said slide slot; an adjustment rod having a substantially U-shaped section, a first end and a second end, said first end of said adjustment rod adjustably joined to said adjustment slot of said pull rod; a spring biasing said pull rod away from said handle portion of said first member; a first roller wheel rotatably mounted to said second end of said adjustment rod; a second roller wheel rotatably mounted to said first member; and a pull rope having an end fixed to said second end of said adjustment rod, a portion engaging said second roller wheel, a portion engaging said first roller wheel and a free end; wherein, manipulation of said pull rope forces said convex blade portion to converge on said concave blade portion and provides a cutting force thereby, and said adjustable rod is extendable or retractable along said pull rod to increase or decrease said cutting force between said concave blade portion and said convex blade portion. 2. An improved pruning apparatus as defined in claim 1, wherein: said adjustment slot further includes a plurality of notches defined in a peripheral surface thereof. 3. An improved pruning apparatus as defined in claim 2, further comprising: http:/11 64. 195.1 OO. l l!netacgi/nph-Parser ... 634276' .WKU.&OS=PN/5634276&RS=PN/56342 I r'1ited States Patent: 5,634,276 a positioner pin, said positioner pin fixed in said first end of said adj ustment rod and releasably securable with one of said notches. 4. An improved pruning apparatus as defined in claim 1, further comprising: a grip section having wave-like contours circumferencially engaging said handle portion. 5. An improved pruning apparatus as defined in claim 1, further comprising: a pull handle having two insertion holes defined therethrough for adjustably engaging said free end of said pull rope. 6. An improved pruning apparatus as defined in claim 1, further comprising: an elongated extension handle connected to said handle portion for increasing a length of said handle portion. 7. An improved pruning apparatus as defined in claim 1, further comprising: a saw blade extending from said first member. Description BACKGROUND OF THE INVENTION The invention herein consists of an improved structure high branch pruning shears that is structurally comprised of a positioner mount, a concave blade, a pull rod, a connecting rod, an adjustment rod, a hinge base, roller wheels, pull rope and other major components, such that the invention herein achieves the objective of enabling the user to obtain significantly greater pruning force while exerting minimal physical effort when pruning trees (branches). When high branch pruning shears are utilized on fruit orchard and other trees, a kind of pruning tool is required to trim the leaves and branches of the taller trees. However, as indicated in FIG. 1, the structure of conventional high branch pruning shears consists of: A positioner mount (10) at the rear end of a hinge base (11) that enables the hinge based (11) to be sturdily conjoined to an extension rod (P) at a hooked ring (9) at the posterior extent of the hinge base (11), and the rear end is curved to form a concave blade (13) with a hole a suitable distance away at the upper extent and a tab (15) protruding from the middle section, as well as a convex blade (17) conjoined at the lower extent of a pull rod (16) and the hinge base (18) on the hole and, furthermore, conjoined to the lower extent of the aforesaid hinge base (18) and the center of the tab (15) is a leaf spring (19), and conjoined to the upper end of the pull rod (16) is a roller wheel (14), and the lower end of the roller wheel (14) is conjoined to pull rope (8) that enables, after the pull rope (8) is inserted through the hooked ring (9) past the roller wheel (14), the aforesaid pull rope (8) to be inserted into and fastened to a knobbed handle (7) and thereby constitute a high branch pruning shears; when such high branch pruning shears are utilized to prune tree branches, the concave blade (13) is first positioned around the tree branch to be pruned and the pull rope (8) is tugged downward to cause the pull rod (16) to move the convex blade (17) towards the concave blade (13) to perform the pruning and after the pruning of the tree branch is completed, the leaf spring (19) in between the hinge base (18) and the tab (1.5)pushes the convex blade (17) back to the original position, however, when a conventional high branch pruning shear is utilized, numerous shortcomings and 3 of 7 611199 11:10 P' H'1ited States Patent: 5,634,276 http://l64. 195.1 OO. l l !netacgi/nph-Parser ... 634276' .WKU .&OS=PN/5634276&RS=PN/56342" inconveniences frequently occur and the aforesaid shortcomings include the following: An unusually high degree of force is required since the pull rope (8) must be tugged downward to cause the pull rod (16) to move the convex blade (17) towards the concave blade (13) for the execution of the pruning action, which necessitates a great deal of energy when pruning and, furthermore, when a coarse tree branch is to be pruned, an even greater magnitude of force is required to prune the tree branch. The shape of the leaf spring is easily defomted because when the pull rod (16) moves the convex blade (17) to execute the pruning action, a bend is produced in the leaf spring (19) and since the leaf spring (19) provides the convex blade (17) with a functional means of returning to the original position, the leaf spring (19) is easily deformed due to periodic subjection to bending over a given span of time, wherein the resilient returningfunction of the convex blade ( 17) gradually deteriorates. The hinge base easily separates from the extension rod, a phenomenon that is attributed to the necessity of inserting the extension rod (P) into the hinge base (11), wherein there is an opening in the hinge base (11) to accommodate the insertion and screw fastening of the extension rod (P) such that when a tree branch of inordinate height is pruned and after the concave blade (13) is positioned over the tree branch to be pruned, the hinge base (11) is frequently loosened from the extension rod (P) and ultimately fails off entirely. The pull rope cannot be effectively adj usted because after the trailing end of the pull rope (8) is inserted into the knobbed handle (7) and fled into a knot for fastening onto the knobbed handle (7), when the pruning of a high tree branch is performed, the aforesaid pull rope (8) has to be of a certain predetermined length to achieve an effective pruning force,, wherein it is often the case that the length of the pull rope (8) must be increased when encountering a tree branch of relatively low height, otherwise, it will be impossible to exert tension on the pull rope (8) with the knobbed handle (7) alone such that the pull rope must be coiled to achieve the length appropriate to exert tension, thereby precluding the utilization of the additional leverage offered by the knobbed handle (7) due to the impossibility of length adjustment. Therefore, the inventor of the invention herein has engaged in the manufacturing and development of high branch pruning shears for many years and applied the resulting experience to overcome the numerous aforementioned disadvantages and inefficiencies characteristic of conventional high branch pruning shears by innovatively improving the aforesaid stmcture, wherein following concentrated research, prototype construction and experimentation, the improved structure high branch pruning shears of the invention herein was perfected and in accordance with the relevant laws, the application for the commensurate patent fights was duly submitted, wherein: The primary objective of the invention herein is to provide a kind of improved structure high branch pruning shears that is structurally comprised of the shears, a concave blade, a pull rod, .an adjustment rod, a handle mount, a saw blade, a pull rope and other major components, including: The shears, of which one side consists of a concave blade and at an appropriate distance from the rear extent of the concave blade is an insertion hole and to the rear of the aforesaid insertion hole is a through-hole; there is a positioner pin riveted below the aforesaid through-hole and a fastening pin is riveted a suitable distance from the upper extent of the aforesaid concave blade, and there is a screw hole at the side of the aforesaid fastening pin. Furthermore, at the lower end of the aforesaid shears is a hinge hole for a screw fastening the handle mount A convex blade that has two insertion holes at the middle and the lower end, respectively, wherein the aforesaid insertion hole at the middle is aligned with the aforesaid insertion hole of the aforesaid shears to form a pivot point and the aforesaid insertion hole at the lower end supports conjoinment into the slide slot 4of7 6!1/99 11.10 P' TTnited States Patent: 5,634,276 http://l64.195.1 OO. l l!netacgi!nph-Parser. ..634276' .WKU .&OS=PN/5634276&RS=PN/56342" of a pull rod. A pull rod that has an insertion hole at the front end to support a recoil spring and a rivet in the insertion hole on the sheers and, furthermore, there is a slide slot centered a suitable distance away on the front end and an adjustment slot is centered a suitable distance away on the rear end, with the adjustment slot provided with a number of notch holes to facilitate incremental adjustment. An adjustment rod that consists of a length of U-shaped metal stock with an insertion hole at the front end a suitable distance away, and at the tip of the front end is an opening and, furthermore, a positioner pin is conjoined to the adjustment slot of the pull rod for positioning into notch holes and, furthermore, a U-shape strip at the trailing end ensconces a roller wheel that is aligned with an insertion hole to enable rotation. A handle mount that has a hinge conjoinment hole centered on the end section which is fastened by threads to the lower end of the sheers and around the circumference at one side is a grip section having wave-like contours, while at the end section of the opposite side is U-shaped component ensconcing a roller wheel and, furthermore, an extension rod is attached to the aforesaid end section. A pull handle that consists of a columnar rod having the two insertion holes drilled through at appropriate points in the center proximity, wherein the insertion holes are provided for the insertion and fastening of a pull rope to thereby facilitate the free adjustment of rope length .. A pull rope, of which one end is firmly guyed to the U-shaped adjustment rod and then routed through and against the respective roller wheels of the handle mount and the adjustment rod, and the opposite end is inserted into the pull handle. Based on the description of the aforesaid structural components of the invention herein, when proceeding to prune tree branches by tugging on the aforementioned pull rope, the adjustment rod can be moved in the adjustment slot within the pull rod to another of the aforementioned notch holes to achieve a greater shearing force, thereby maximizing pruning efficiency and requiring minimum physical effort. The improved structural innovations of the invention herein are further elaborated below through the brief description of the drawings attached below which in combination with the detailed description of the invention herein following, shall serve as a reference for the examination committee. The aforesaid drawings and the respective descriptions are as follows: BRIEF DESCRIPTION OF THEDRAWINGS FIG. 1 is a structural drawing of a conventional high branch pruning shear. HG. 2 is an isometric drawing of the structure of the invention herein. FI G. 3 is an exploded isometric drawing of the structure of the invention herein. FIG. 4 is an orthographic drawing illustrating the first operational procedure in structural detail of the invention herein. FIG. 5 is an orthographic drawing illustrating the second operational procedure in structural detail of the invention herein. 5 of 7 611/99 11:10 p; TT11ited States Patent: 5,634,276 http:l/164. 195.1 OO. l l/netac:gi/nph-Parser. ..634276' .WKU.&OS=PN/5634276&RS=PN/56342- FIG. 6 is an orthographic drawing depicting the movement of the adjustable rod of the invention herein. DETAILED DESCRIPTION OF THEINVENTION As indicated in FIG. 2, FIG. 3, FIG. 4, FIG. 5 and FIG. 6 and with specific reference to FIG. 2 and FIG. 3, the improved structure high pruning shears (20) of the invention herein includes: The shears (20), of which one side consists of a concave blade (21) and at an appropriate distance from the rear extent of the concave blade (21) is an insertion hole (22) and to the rear of the aforesaid insertion hole (22) is a through-hole (23); there is a positioner pin (24) riveted below the through-hole (23) and a fastening pin (25) is riveted a suitable distance from the upper extent of the concave blade (21), and there is screw hole (26) at the side of the fastening pin (25). Furthermore, at the lower end of the shears (20) is a hinge hole (61) for screw fastening a handle mount (60) to the invention herein. A convex blade (30) that has the insertion holes (31) and (32) at the middle and the lower end, respectively, wherein the insertion hole (31) at the middle is aligned with the insertion hole (22) of the shears (20) to form a pivot point and the insertion hole (32) at the lower end supports conjoinment into the slide slot of the pull rod (40). A pull rod (40) that has an insertion hole (41) at the front end to support a recoil spring (42) and a rivet in the through hole (23) on the shears (20) and, furthermore, there is a slide slot (43) centered a suitable distance away on the front end and an adjustment slot (44) is centered a suitable distance away on the rear end, with the adjustment slot (44) provided with a number of notch holes (45) to facilitate incremental adjustment. An adjustment rod (50) that consists of a length of U-shaped metal stock with an insertion hole (51) at the front end a suitable distance away, and at the tip of the front end is an opening (52) and, furthermore, a positioner pin (53) is hinged to the adjustment slot ( 44) of the pull rod (40) for positioning into the notch holes (45) and, furthermore, a U-shape strip (56) at the trailing end ensconces a roller wheel (54) that is aligned with the insertion hole (55) to enable rotation. A handle mount (60) that has a hinge conjoinment hole (61) centered on the end section which is fastened by threads to the lower end of the shears (20) and around the circumference at one side is a grip section (62) having wave-like contours, while at the end section of the opposite side is aU-shaped component (63) ensconcing a roller wheel (64) and, furthermore, an extension rod (65) is attached to the aforesaid end section. Referring now also to FIG. 4 a pull handle (70) that consists of a columnar rod having the two insertion holes (71) and (72) drilled through at appropriate points in the center proximity, wherein the insertion holes (71) and (72) are provided for the insettion and fastening of a pull rope (80) to thereby facilitate the free adjustment of rope length. A pull rope (80), of which one end is firmly fixed to the U-shaped adjustment rod (50) and then routed through against the roller wheels (64) and (54) of the handle mount (60) and the adjustment rod (50), respectively, and the opposite end is inserted into the pull handle (70). As indicated in FIG. 4 and FIG. 5, the operational descriptions of the aforesaid structural composition of the invention herein, when proceeding to prune tree branches, one hand grasps the lower extent of the extension rod (65) and the other hand tugs the pull handle (70) on the pull rope (80), whereupon the concave blade (8) is first positioned on the tree branch to be pruned, after which the pull rope (80) is drawn 6 of 7 611199 11:10 PW T T'lited States Patent: 5,634,276 http:/1 1 64. 195.1 00. 1 llnetacgi/nph-Parser..o634276' .WKU.&OS=PN/5634276&RS=PN/56342� downward, thereby subjecting the adjustment rod (50) to a downward force that causes the movement of the pull rod (40) and initiates the consequent pivoting of the convex blade (30) at the hinged juncture on the shears (20), following which the convex blade (30) completes the pruning of the tree branch. Furthermore, in the event that a coarse tree branch is encountered during the pruning operation that cannot be pruned (Referring now to the function of the adjustment rod depicted in FIG. 6.), the pull rod (40) that pivots on the shears (20) is brought into utilization, wherein the adjustment rod (50) is raised higher in the adjustment slot (44) within the pull rod (40) which causes the rearward movement of the positioner pin (53) and consequent slide into the next lower notch hole (45) to achieve a greater shearingforc e and thereby effectively maximizing pruningeff iciency and, furthermore, resulting in pruning tool that requires minimum physical effort during the trimming of tree branches. However, as indicated in FIG. 2, when the aforementioned tree branch to be pruned is off excessively large diameter as positioned against the convex blade (30) of the shears (20), then the saw blade (90) on the fastening pin (25) positioned at the upper extent of the concave blade (21 ) is prepared for utilization, wherein the retaining wing nut of the saw blade (90) is tightened to secure the saw blade (90) so that coarse tree branches (trunks) can be efficiently cut. Furthermore, after the completion of cutting a coarse tree branch (trunk), can be placed under the extension rod (65) of the shears (20), wherein due to the design of the handle mount (60) at the lower end of the shears (20) provides the user with an exception handle section that includes and holds a suitable saw blade for priming tree branches (trunks) that significantly increases the practical effectiveness of high branch pnming shears, Referring now to the pull handle illustrated in FIG. 4., the structure of the aforesaid pull handle (70) includes the two insertion holes (71) and (72), wherein after the aforesaid pull rope (80) is inserted through the insertion hole (71) in the pull handle (70) and the pull rope (80) is then inserted into the insertion hole (72) of the aforesaid pull handle (70), the insertion results in the formation of a semi-circular knot around the pull handle (70), which is then tightened into a fi xed position through tension, and when the length of the pull rope (80) requires adjustment, the length of the pull rope (80) can be varied after the aforesaid knot is loosened, which thereby provides for a pull rope (80) that can be freely adjusted in length as necessary. In summation of the foregoing description, the invention herein improves upon the broad range of shortcomings common to all conventional high branch pruning shears and, furthermore, the structural composition of the invention herein in terms of efficiency and practical effectiveness features simplicity and innovation and, therefore, is in compliance with new patent fight application requirements and is hereby submitted for evaluation pursuant to the awarding of the commensurate patent rights in accordance with the relevant laws. ***** - 7 of 7 611199 11: 10 Pl\i T T'1ited States Patent: 5,044,083 http://l64.195. 1 OO. l llnetacgi/nph-Parser. . . 044083' .WKU .&OS=PN/5044083&RS=PN/50440l ( 1 of 1 ) United States Patent 5, 044,083 DeCarolis , et al. September 3, 1991 ------Telescoping hacksaw frame Abstract A hacksaw has an adjustable frame with an elongated rear frame member having an inverted U-shaped cross section and providing a downwardly opening channel. The rear frame rearward end portion is secured in the upper portion of the hand grip and its side walls adjacent the forward end have lower portions which extend inwardly and incline upwardly towards the forward end to provide an upwardly inclined ramp. This ramp substantially closes the channel and terminates in a lip at the forward end of the frame member, and the top wall and side walls adjacent thereto are relieved above the ramp. A front frame member of bar-like configuration having a bridge portion seated in the channel of the rear frame section, and a depending leg portion at its forward end which has a blade mounting element adjacent its lower end. The bridge portion has spaced recesses in its bottom edge in which the lip of the ramp is seated. The frame also has a rear leg member extending below the rear frame section forwardly of the hand grip, and its upper end portion is seated in the upper end of the hand grip. This leg member has blade mounting element adjacent its lower end cooperating with that of the front frame member to secure a blade extending therebetween. The length of the frame is adjustable by pivoting upwardly the front end of the front frame member to disengage the ramp from the recess of the bridge portion, and the bridgeportion is slid within the channel of the rear frame member to align a desired recess therein with the ramp. Inventors: DeCarolis; Joseph P. (Bristol, CT); Korfmacher; Allen F. (York, PA) Assignee: The Stanley Works (New Britain, CT) Appl. No.: 621292 Filed: November 30, 1990 U.S. Class: 30/510 Intern'l Class: B23D 051103 :Fieldof Search: 30/507,510,511,517 References Cited (Referenced 1!YJ. U.S. Patent Documents I of 7 611199 11:12 PI\' T T'1ited States Patent: 5,044,083 http :/1164. 195.1 00. 1 1/netacgi/nph-Parser ...04 4083' .W KU .&OS=PN/5044083&RS=PN/50440l 487358 Dec., 1892 Whelpley. 1473803 Nov., 1923 Adell et al.. 1565861 Dec., 1925 Mcintire. 1569408 Jan., 1926 Spartivento. 1610381 Dec., 1926 Jacobey. 2014722 Sep., 1935 Damon. 2219136 Oct., 1940 Mills et al.. 2388655 Nov., 1945 Lenla 30/3 11. 2580896 Jan., 1952 Dohner. 2941558 Jun., 1960 Dreier 30/5 10. 3173461 Mar., 1965 Johnson 30/5 10. Primary Examiner: Watts; Douglas D. Claims 1. In a hacksaw having an adjustable frame, the combination comptising: (a) a hand grip; (b) an elongated rear frame member having an inverted U-shaped cross section definedby a top wall and depending side walls and providing a downwardly opening channel, said rear frame member having its rearward end portion secured in the upper portion of said hand grip, said side walls adjacent the forward end thereof having their lower portions extending inwardly and inclined upwardly towards said forward end to provide an upwardly inclined ramp substantially closing the channel and terminating in a lip at the forward end of said frame member, the top wall and side walls adjacent thereto being relieved above said ramp; (c) a front frame member of generally vertically oriented bar-like configuration having an elongated bridge portion with its rearward end portion seated in said channel of said rear frame section, said front frame section having a depending leg portion at the forward end of said bridge portion and blade mounting means adj acent the lower end of said leg portion, said bridge portion having a multiplicity of spaced recesses in its bottom edge, said lip being seated in one of said recesses; and (d) a rear leg member extending below said rear frame section forwardly of said hand grip, said rear leg member having its upper end portion seated in the upper end of said hand grip, said leg member having blade mounting means adjacent its lower end cooperating with that of said front frame member to secure a blade extending therebetween, the length of said frame being adjustable by pivoting upwardly the front end of said front frame member to disengage said lip from the recesses of said bridge portion and sliding said bridge portion within said channel of said rear frame member to align a desired recess therein with said lip and pivoting the bridge portion downwardly to effect engagement therewith. 2. The hacksaw in accordance with claim 1 wherein said inwardly extending portions of the sidewalls of said rear frame member abut. ? 7 JT'lited States Patent: 5,044,083 http:l/ 1 64. 195.1 00. 1 1/nctacgi/nph-Parscr...044083' .WKU.&OS=PN/5044083&RS=PN/50440. 3. The hacksaw in accordance with claim 2 wherein said opposed edges are secured together. 4. The hacksaw in accordance with claim 1 wherein the relieved side walls of said rear frame section extend rearwardly and upwardly from the front end to said top wall. 5. The hacksaw in accordance with claim 1 wherein said rear leg member is of generally bar-like cross section with its upper end portion extending upwardly and rearwardly into said hand grip. 6. The hacksaw in accordance with claim 5 wherein said upwardly and rearwardly extending upper end portion extends within said channel of said rear frame member. 7. The hacksaw in accordance with claim 1 wherein said recesses are of inverted U-shaped configuration and have a length approximating that of said ramp to seat said ramp snugly within said recesses. 8. In a hacksaw having an adjustable frame, the combination comprising: (a) a hand grip; (b) an elongated rear frame member having an inverted U-shaped cross section defined by a top wall and depending side walls and providing a downwardly opening channel, said rear frame member having its rearward end portion secured in the upper portion of said hand grip, said side walls adjacent the forward end thereof having their lower portions extending inwardly and inclined upwardly towards said forward end to provide an upwardly inclined ramp substantially closing the channel and terminating in a lip at the forward end of said frame member, said inwardly extending portions of the side walls of said rear frame member abutting, the top wall and side walls adjacent thereto being relieved above said ramp; (c) a front frame member of generally vertically oriented bar-like configuration having an elongated bridge portion with its rearward end portion seated in said channel of said rear frame section, said front frame section having a depending leg portion at the forward end of said blidge portion and blade mounting means adjacent the lower end of said leg portion, said bridge portion having a multiplicity of spaced recesses in its bottom edge, said recesses being of inverted U-shaped configuration and having a length approximating that of said ramp to seat said ramp snugly within said recesses, said lip being seated in one of said recesses; and (d) a rear leg member extending below said rear frame section forwardly of said hand grip, said rear leg member having its upper end portion seated in the upper end of said hand glip, said leg member having blade mounting means adjacent its lower end cooperating with that of said front frame member to secure a blade extending therebetween, the length of said frame being adjustable by pivoting upwardly the front end of said front frame member to disengage said lip from the recesses of said blidge portion and sliding said blidgeportion within said channel of said rear frame member to align a desired recess therein with said lip and pivoting the blidge portion downwardly to effect engagement therewith. 9. The hacksaw in accordance with claim 8 wherein said opposed edges are secured together. 10. The hacksaw in accordance with claim 8 wherein the relieved side walls of said rear frame section extend rearwardly an upwardly from the front end to said top wall. 11. The hacksaw in accordance with claim 8 wherein said rear leg member is of generally bar-like cross section with its upper end portion extending upwardly and rearward.ly into said hand grip. 12. The hacksaw in accordance with claim 11 wherein said upwardly and rearwardly extending upper end 3 of 7 611/99 1 :12 TT'lited States Patent: 5,044,083 http:l!164. 195.1 OO. l llnetacgi/nph-Parser... 044 083' .WKU.&OS=PN/5044083&RS=PN/50440 portion extends within said channel of said rear frame member. Descrip tion BACKGROUND OF THE INVENTION The present invention relates to hacksaws and, more particularly, to hacksaws with telescoping frames. Hacksaws are widely employed for cutting metal and the like, and variousblades are made from different metal alloys or provided with special cutting coatings for use therein. Moreover, depending upon the workpiece to be cut, hacksaws with different length blades may be used to provide a longer or shorter cutting stroke. Seven and nine inch blades are fairly standard, and some hacksaws are provided with frames which will permit adjustment in the length of their bridge portion to enable use of blades of multiple sizes. In most instances, the frames use telescoping elements to provide the adjustment and some provide detents, pins, rivets or other means to provide some stability in the adjusted positions. Some hacksaw frames providing such adjustability with good positioning elements are rather expensive to fabricate, and others provide positioning elements which are not particularly effective or which are relatively short lived. As will be appreciated, slippage of the frame in length from its adjusted position can produce undesired compressive of other forces on the blade. Illustrative of such devices are Whelpley U.S. Pat. No. 487,358, Adell et al U.S. Pat. No. 1,473,803, Mcintire U.S. Pat. No. 1,565,861 and Spartivento U.S. Pat. No. 1,569,408. In such telescoping constructions,. one of the frame elements generally fits within a channel or cylindrical cavity formed in the other, and there is provided some form of locking on the two elements to maintain the frame in an adjusted position. For several years, Applicants' assignee, The Stanley Works, has marketed a telescoping hacksaw frame utilizing a rear frame member having an inverted channel shaped configuration in which is received a bar-shaped front frame member. A rivet is provided in the channel shaped rear member and it seats in relatively narrow but deep notches formed in the front frame member. A relatively wide slot is provided in the top wall of the rear member adj acent the rivet in order to permit pivoting of the front element relative to the rear frame member in order to effect relative sliding motion Although this structure has been generally satisfactory, it has presented some problems from the standpoint of relative weakness in the area where maximum stress occurs, i.e., about the engagement between the two elements. It is an object of the present invention to provide a novel telescoping hacksaw frame which may be fabricated economically and which enables stable positioning of the frame elements in their adjusted position. It is also an object to provide such a frame which may be adjusted simply and quickly. Another object is to provide such a frame in which the components may be fabricated from sheet metal or like stock by relatively economical and simple techniques. SUMMARYOF THE INVENTION It has now been found that the foregoing and related objects may be readily attained in an adjustable hacksaw which has a hand grip and an elongated rear frame member of inverted U-shaped cross section definedby a top wall and depending side walls providing a downwardly opening channeL This member has its rearward end portion secured in the upper portion of the hand grip, and its side walls adjacent the 4of7 611199 11:12 Pfl http:!1164.195.100. l l !netac:gi/nph-Parser. .. 044083' .WKU.&OS=PN/5044083&RS=PN/50440! l 1>Jited States Patent: 5,044,083 forward end have their lower portions extending inwardly and inclined upwardly towards the forward end to provide an upwardly inclined ramp substantially closing the channel and terminating in a lip at the forward end of the frame member. The adjacent top wall and side walls are relieved above the ramp. A front frame member of generally vertically oriented bar-like configuration has an elongated bridge portion with its rearward end portion seated in the channel of the rear frame section. At the forward end of the bridge portion, the front frame section has a depending leg portion with blade mounting means adjacent its lower end. The bridge portion has a multiplicity of spaced elongated recesses in its bottom edge, and the lip of the ramp Is seated in one of the recesses. A rear leg member extends below the rear frame section forwardly of the hand grip, and has its upper end portion seated in the upper end portion of the hand grip. The leg member has blade mounting means adjacent its lower end which cooperates with that of the front frame member to secure a blade extending therebetween. The length of the frame is adjustable by pi voting upwardly the front end of the front frame member to disengage the ramp from the recess of the bridge portion and then sliding the bridge portion within the channel of the rear frame member to align the desired recess with the lip, after which the bridge portion is pivoted downwardly to effect engagement therewith. Preferably, the inwardly extending portions of the sidewalls of the rear frame member abut. If so desired to provide greater rigidity, the opposed edges may be secured together, conveniently by welding. The relieved side walls of the rear frame section extend rearwardly and incline upwardly from the front end to the top wall. The rear leg member is of generally bar-like cross section with its upper end portion extending upwardly and rearwardly into the hand grip, most desirably within the channel of the rear frame member to which it may be welded if so desired. Preferably, the recesses are of inverted U-shaped configuration and have a length approximating that of the ramp to seat the ramp snugly within the recesses. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of an adjustable hacksaw embodying the present invention; FIG. 2 is a fragmentary side elevational view of the disassembled front and rear sections of the frame; FIG. 3 is a fragmentary bottom view of the forward portion of the rear section of the frame; FIG. 4 is a fragmentary exploded view of the telescoping portions of the front and rear sections of the frame; FIG. 5 is a fragmentary side elevational view in partial section of the telescoping sections of the frame showing the front section pivoted upwardly to disengage the front section from the engaging element on the rear section; FIG. 6 is a similar view with the front section pivoted downwardly and engaged; and FIG. 7 is a similar view, but with the front section moved forwardly into a second adjusted position. DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODHvffiNTS Turning first to FIG. 1 of the attached drawings, a hacksaw embodying the present invention is comprised of the handle or hand grip generally designated by the numeral 10, a rear frame section generally 5 of 7 6/1/99 '1'1ited States Patent: 5,044,083 http:l/164.195.1 OO. l l/netacgi/nph-Parser... 044083 ' .W KU.&OS=PN/5044083&RS=PN/50440: designated by the numeral 12, a front frame section generally designated by the numeral 14, the hacksaw blade 16, and a rear leg member designated by the numeral 30. Turning first to the detail of the rear frame section 12, it is of generally inverted U-shaped configuration with a top wall 20 and side walls 22 providing a downwardly opening channel 24 therebetween. The rearward end 17 extends into, and is fi rmly secured within, the upper portion of the hand grip or handle 10, and the bridge portion 18 extends forwardly therefrom. Adjacent its forward end, the lower portions of the side walls 22 are bent inwardly and inclined upwardly to provide a ramp 26 which terminates in a lip 27. As indicated in FIGS. 3 and 4, the opposed edges of the inwardly bent portions of the ramp 26 abut, and they may be tack welded or otherwise bonded together to provide greater rigidity if so desired. Above the ramp 26, the side walls 22 and the top wall 20 are relieved as indicated by the arcuate cutout 28. Also illustrated In FIGS. 3 and 4 is a small pilot hole 29 which is utilized during the forming operation. The front frame section 14 is conveniently formed from flat bar stock with a bridge portion 40 which telescopically fitswithin the channel 24 of the rear frame section 12 and a depending leg portion 42 at its forward end. In the bottom edge of the bridge portion 40 are a pair of spaced elongated U-shaped recesses 50. The leg portion 42 is formed with a slotted offset portion providing a pair of forks 44,46 between which the saw blade 16 extends, and the forw ard fork 46 has a horizontally projecting pin 48 which seats within the aperture formed at the forward end of the blade 16. At the rearward end of the frame, the depending leg 30 is formed from bar stock with a relatively planar body portion 34. The lower end portion 32 is bent so that it lies in a plane perpendicular to the plane of the blade 16, and it seats the tension bolt 36 in an aperture extending therethrough, and the wing nut 38 is engaged thereon. The tension bolt 36 includes a pin portion 52 which fitswithin an aperture at the rear end of the blade 16 and a positioning lip 54 captures the rear edge portion of the blade 16 as is conventional. When it is desired to substitute a blade 16 of different length, the wing nut 38 is loosened to relieve the tension upon the blade 16, and the blade 16 is disengaged from the pins 52 and 48. As indicated in FIG. 5 of the drawings, the front end section 14 may now be pivoted upwardly to disengage the lip 27 from the recess 50 in which it is seated. As will be appreciated, the relieved portion 28 allows the front frame section 14 to pivot upwardly to the released position. With the forward frame section 14 so pivoted, it may now be moved to a position in which the lip 27 is aligned with the desired recess 50, at which time the front frame section 14 is again pivoted downwardly to seat the lip 27 in the recess 50 correspondingto the desired length of blade to be employed. As will be readily appreciated, the shallow recesses 50 minimize the weakening of the bar stock providing the front frame member, and the abutting and bonded portions of the side walls providing the ramp 26 enhance the strength of the forward frame section which has its walls relieved to permit pivoting of the front section. The ramp surface 26 with its lip 27 seat relatively securely in the elongated recess 50 to provide a fairly stable assembly when the blade is tensioned between the front leg portion 42 and the rear leg 30. In the illustrated embodiment, it can be seen that the upper portion 35 of the rear leg portion extends into the channel 24 of the rear section 12 and into the handle 10 and then downwardly therefrom. This configuration minimizes the cross section utilized for seating the metallic elements of the frame. At the same time it enables the two metallic members to be spot welded to provide a relatively high strength bond therebetween and then with the resin of the handle. Although only two recesses have been shown in the illustrated embodiment, additional recesses may be provided for still other length blades and the recesses may be reduced in length to limit further the relative 6 of 7 6/l /99 ! 1:12 TT'lited States Patent: 5,044,083 http:l!1 64. 195.1 OO. l l /netacgilnph-Parser. .. 044083' .WKU .&0S=PN/5044083&RS=PN/504401 movement permitted in any adjusted length. In fabricating the frame, the bridge element of the rear section is blanked from sheet metal, and the blanking or a subsequent operation may provide one or more stiffening ribs or corrugations along the length of the portions to form its sidewalls. The blanking step may conveniently provide the cutout for the contoured front edges of the sidewalls and the relieved section of the top wall. The blanked piece is then formed in one or more dies to provide the U-shaped configuration of the channel and the inturnedportions at the front end to form the lip. To provide higher strength in the lip, the internalportions are spot or butt welded along their abutting edges The front bridge section and the depending leg of the rear section are blanked from thicker metal stock in their intended contours to provide relatively stiff elements of solid cross section. The forward section has its leg portion slit and deformedto provide the blade gripping elements, and the rear leg is deformed and pierced to provide its blade mounting portion to seat the draw bolt. The means of engagement of the rear section elements in the handle may vary. From the standpoint of easy and economy of assembly, the handle may be preformed in two halves from synthetic resin with recesses into which the subassembly of the rear frame and rear leg is fitted,and the two halves are then bonded. If so desired, barbs may be provided on the sidewalls of the bridge portion and the downwardly extending portion of the leg to engage the plastic and resist withdrawal from lthe slot in the handle. One or more locking pins or rivetsextending through the sides of the handle and the metal elements may also be used. Alternatively, the handle can be molded about the metal subassembly which is preferred when the handle is fabricated from an elastomer. Thus, it can be seen from the attached drawings and the foregoing detailed specification, that the hacksaw of the present invention provides a frame which is readily adjustable and which eliminates the need for a separate rivetor fastening element to secure the telescoping sections in adjusted position. The several components may be readily fabricated and assembled to provide a structure which is economical and relatively long-lived. ***** - 7 of 7 6/1/99 11:12 PM A.ppendix B Tables B-1 Pressure Washers B-2 Shearing Devices B-3 Nozzles B-4 Poles Pressure Washers Pressure Flow rate Hose Hose Power Device HP/Engine Cost (psi) (gpm) Length Dia sorce 4.5/Briggs and Sears 76180 1800 2 25' 1/4" $349.99 Gas Staton Quantum Hotsy 970 2000 3.8 5h.p/ 230V 50' 3/8" $4,300.00 Electric I Delco 2004cw 2000 4 5h.p/ 220V 50' 3/8" $1 ,340 Electric Hotsy 965 3000 3 9h.p 50' 3/8" $5,500.00 Gas I I I I I I Delco SS3004 3000 4 13/Honda 50' 3/8" $1 ,995.00 Gas . 13/Collar Command Sears 76350 3500 4 50' 3/B" $1 ,699.99 Gas OHV Delco 5-4000 • r " $4 ,995.oo Gas 4000 4.:J 18Nanguard 50' 3/8 I ------_j I I I S�earing d�vices Device Cut Reach Diameter Weight Power Cost Useage Pressure Corona bypass 11 3' 2.25 TBD hand $49.07 Profesional N/A lom:>er I I Maibo 3-4' 2.25" 61bs. pneumatic $495 Profesional 140 psi t:dI SE-6B N CoronaWL 11 3' 3 TBD manual $129.95 Profesional N/A 6490 1 Newdraulics 11 T 2.25 11 1bs. hydraulic TBD Profesional 2000 psi Giant Pruner I 11 hand EZ Prune 14' 1.75 6.5 1bs. $190 Home N/A hydraulic 1 Husqvarna 1 5 . 7.5 1bs. hydraulic . Profesional 1600 psi FLOW RATE Gallons per minute 0 ?rificediamet r ,, MS.O j ,i.72�Q 145 0 21750 29000 36250 43500 50750 58000 3;mm,1:�j: 1 ,'m; 1 , ps1 ·· > pst ps1 ps1 ps1 ps1 ps1 ps1 0.1 0.004 IH: 0.psi02 0.04 0.05 0.07 0.08 0.09 0.10 0.10 0.1 1 0.2 0.008 0.07 0.16 0.22 0.27 0.31 0.35 0.38 0.41 0.44 0.3 0.012 0.16 0.35 0.50 0.61 0.70 0.79 0.86 0.93 1.00 1.08 1.53 1.65 ' 0.4 ; /0.016 !�10.28 ,' t, OB2 ' I· ' 0;88 1.25 1.40 1.77 >.0.5\'I ; 0.020 '�� 0.44 7 ·'.· 1.38 1.69 :'1.95 2.18 2.39 '''; . �· �. \ 1 . 6 �\ 2.58 2.76 . >; :o'n· .�f'·o··a3 , ls\.'4·4· 314 . 0 • 6 .,, ' . 24· • • ' 0 49• 9 2 . · ·2·8-� 72 ": ' 1,;.1 ��: :� · · I•'! . I . I 43 . I . . 34. 4 3 . 3 . 9' I 0.7 0.028 0.86 1.91 2.71 3.31 3.83 4.28 4.68 5.06 5.41 0.8 0.031 1.12 2.50 3.27 4.33 5.00 5.59 6.12 6.61 7.07 t:dI w 0.9 0.035 1.41 3.16 4.47 5.48 6.32 7.07 7.75 8.37 8.94 ' 1 .0;.:•. ·0.039 .j�f;'1.74 7.81 9.56 ··•••· .. ,.; >3.90 5.52 6.76 8.73 10.33 11.06 �.;0.043 zt' 4.72 8.18 .. 9.45 10.56 11:57 12.50 ... 1,1•i"r �r2}1f·,;t ;1 6.68 13.36 1 \y{ 1 �2 1>s' ' 3·���0.047 ,�2.52 ;;� �:�5.62 �• :\{;Q5 9.74 11�25 12.57 14.87 ···· 13177 ·• 15.90 ; 1.3 0.051 2.95 6.60 9.33 11.43 13.20 14.75 16.16 17.46 18.66 1.4 0.055 3.42 7.65 10.02 13.25 15.31 17.1 1 18.74 20.25 21.64 1.5 0.059 3.90 8.78 12.42 15.21 17.57 19.64 21.52 23.24 24 .85 .{1.6/.,. ·! ·.��=0.063 1�4 47 �: l� 10.00· 14.13 17.31 .19.99 22.35 24.48 26.44 43.99 ·�:S1;:l 1��: 6li20.0671J�� 5:05 I;� �t t1 �28 '' 15.96 19.54 ·22.57 25.23 27.64 29.85 31 .91 ���� �� 17".89� . 21.91 Z25:30 28.29 '30:99 �t;; i� 1.8�f�z ' ;,r+�i (l:011i 5f4'5.66'·�· 2;55'(; · . ·· 33�47 35.80 ; 1.9 0.075 6.30 13.83 19.93 24.4 1 28.19 31.50 34.52 37.29 39.87 41 .3 2.0 0.079 6.98 15.62 22.09 27.05 31.24 34.92 38.25 2 A4JL �,_, �w ,_._. ' POLES Model Sections Length Diameter Material Weight Price Ambient, QP4140 n/a 4.7'-16.2' n/a Carbon fiber 33.6 oz $385.00 Ambi en, QP4150 5 4.9'-17.9' n/a Carbon fiber 23 oz $605.00 K-tek, K251 5 4.7'-21' n/a Graphite fiber 28 oz $750.00 c:dI .. Van Den Bergh, XL 6 4411 - 18.3' n/a Carbon fiber 20 oz $650.00 XTD-81 6F n/a 8' -16' n/a Fiberglass n/a n/a I I I I I I XTD-816A n/a 8' -16i n/a Aluminum n/a n/a , Mr. LongAr m , 2300 3 8.25' - 23' 1.25'' Fiberglass n/a n/a ; Mr. LongArm , 6600 4 8 .25' - 23 .25' 1.25" Fiberglass, Alum n/a n/a Steccone 4 6i - 24i n/a AlloY ...... n/a n/a I I ,Appendix C Material Properties C-1 Materials properties (wood) C-2 Materials properties . . "w • Chapter 23 I \laterial�. �S ,. l ecuon• anti 0 csi":::n (�.nnslder· tr· o,- 10.000 =------ I i !- r- Engineering 3 :o Search Results http://wwwomatwebocom/SpecificMaterialoasp?bassnum=ETHORJ&group=Genei Thornel® Carbon Fiber P-lOOS 2K, Pitch F�recursor Category: Ceramic Subcategory: Carbon Fiber; Carbon; Close Analogs: Key Words: ThornelCarbon Fiber P-lOOS 2K, Pitch ; Carbon Fibre; Amoco Perlormance Products, Inc.; Composition: Material Notes: Data provided by the manufacturer, Amoco Perfonnance Products, Inc. Continuous filament, ultra high modulus fibers consisting of 2000 filaments in a one-ply construction. The fiber surlace has been treated to increase the interlaminar shear strength in a resin matrix composite. 2000 filaments/strand, 0.32 mig yield, 0 or 32 tpm twist Click here to see a list of companies that sell this material. I PHY�ICAL PROPERTIES I VALUES fOoMMENTS 1 Toensity, 2 1 0 ;-;mits:! . ° I glee ;1 3 r- ��E����Ig)\L �� 612199 12:30 AM Search Results httpJ/www,matweb,com/SpecificMaterial,asp'�bassnum=MA601 6&group=GeneJ .s'ptJcla:lty.sYt��tJ!fl. 7o�(J Fairfield, NJ Phone 973-808-8300 Fax 973-808-4488 Aluminum 6061-T6; 6061-T651 Category: Metal Subcategory: Aluminum Alloy; Nonferrous Metal; 6000 Series AluminumAlloy Close Analogs: Four Other Tempers of This Alloy Key Words: Aluminum 6061-T6; UNS A96061; ISO AlMg lSiCu; Aluminium 6061-T6, AD-33 (Russia); AA6061-T6; Aluminum 6061 -T651; UNS A96061; ISO AlMglSiCu; Aluminium 6061-T65 1, AD-33 (Russia); AA6061-T65 1; Composition: .-w_ ____ Comp�, j t. o/to j Component I '"'t. % rc;m ponent I Wt. % I - e i Si oA o.8 Fe ax 0.7 u 0.15 - 0.4 lMax- 0.15, ! [M 1.2 Il Cr � 0.04 - 0.35 - !M;---,Zn 1 Max 0.25 �Ti -, , -fD.sax- 0.15 -� 98 I l I [M fAl , Material Notes: References. General 6061 characteristics and uses (from Alcoa): Excellent joining characteristics, good acceptance of applied coatings. Combines relatively high strength, good workability, and high resistance to corrosion; widely available. The T8 and t9 tempers offer better chipping characteristics over the T6 temper. Uses: Aircraft fittings, camera lens mounts, couplings, marines fittings and hardware, electrical fittings and connectors, decorative or misc. hardware, hinge pins, magneto parts, brake pistons, hydraulic pistons, appliance fittings, valves and valve parts. This and a wide range of alloy/carbon steels,, stainless steels, nickel alloys, titanium alloys, tool steels, aluminum alloys, and tungsten/moly grades are available from Specialty Steel & Forge, (973) 808-8300, www .steelforge.com. Click here to see a list of companies that sell this material. r r--- i PHY------SICAL PROPERTIES [V.------ALUES [COMMEN------TS ------� r------��---- Density, See other glee 1 units kg Hardness, Brinell ,-----500 -----load------with 10------mm------ball ------ I of3 612199 12:32 AM Search Results http:1 lw ww .matweb .com/S pecificMaterial.asp ?bassnum=MA60 l 6&group=Genei I Hardness, Knoop 1120 I Converted from Brinell Hardness Value r------�·HardneSS,------��----- Rockwell A Converted from Brinell Hardness Value Hardness, Rockwell B Converted from Brinell Hardness Value Hardness, Vickers Converted from Brinell Hardness Value MECHANICAL PROPERTIES COMMENTS Tensile Strength, Ultimate, MPa Tensile Strength, Yield, MPa Elongation %; break In 5 em; Sample 1.6 mm thick ,---- Average of Tension and Compression. In Aluminum Modulus of Elasticity, GPa 69 alloys, the compressive modulus is typically 2% 1 greater than the tensile modulus ,...... :.;;:..:._,__ Notched Tensile Strength, 2.5 em width x 0.16 em thick side-notched specimen, MPa 324 �="17. Ultimate Bearing Strength, iMl Pa 1i 607 Edge· distance/pin diame1ter = 2.0 ing Yield Strength, ��: Edge distance/pin diameter = 2.0 � 0:.:..;..3:.:....3__;.:.:_::...... : 1 I I Poissons Ratio '!,�", ;-- Estimated from trends insilllllar A alloys. see other atigue Strength, MPa ,.1 9_5___ 1 5oo,ooo,ooo Cycles I units i!!F l i I IF___ _-______-- -'------l racture Toughness.- 29 r-----K1c; lrL orientation. See other 1 MPa-m% j .,1 units ! Machinability 5o 0-100 Scale of Aluminum Alloys I I __------'--';...... _-..:.:..c_;=, Shear Modulus, GPa 6 Esti�1ated fro� similar AI alloys. ==-==:::.:.. � _ ...... I �hear Strength, a , 205 I �P � ... units � E L R IES , S �-EN. T ��J\ .� t:)���! ... 1\��� �M � .. : CTE, linear 202C, 1Jrn/m-°C ·.· 23 6 !20-1002C ----·------, See other � ,!YJ . units I 1 -'---- CTE, linear 2502C, r::::-:-:- . See other '_ I.. 25.2 E st 1ma' t e d romf t d ren s 1 smu. .1 ar AI a II oys. 20-300° C �IJ:.:.:rn/:.:.;::.:.;:m:.;;;-""o""c===��=.::...·=.:d j � . units .::.;; u u ;;.;;;..c.:;:..;;_c_ . • ·.::.:..:.::;;.;;;: n • ...... ��: ::.::..c.: Heat Capacity, J/g-°C 0.896 . r� ther l !I ---- r--�----�----��---·�� r '·�------Thermal Conductivity, ; See other W/m-K :1 167 r 1! .1 :J units ,---���------.::.:;_--� �------,.I·.------�--;_;_------�------�-- r------::...... : Melting Point, oc Solidus, oc L of 3 612199 12:32 AM Appendix D Analysis and calculations D-1 W aterjet Velocity Calculations D-2 Waterjet Velocity vs. Pressure Calculations D-3 Cutting Force Calculations D-4 Waterjet Cutting Time Calculations D-5 MathCad Shear Calculations D-6 Sum of Forces on Beam D-7 Meq, Stiffness D-8 Dynamic in the pole Waterjet velocity calculations Orifice Diameter Hose Diame�ter Pressure from washer Atm. Pressure d2 := .043 ·in dl := .375·in Pl := 3500 ·psi P2 := 14.7 ·psi Density of Water Area of orifice diameter Area of hose Diameta· slug rc 2 rc 2 p := 1.94 ·- A2 := -·d2 AI := -·dl 3 ft 4 4 Diameter Ratio d2 � .- - � =0.115 dl Flowrate from pressure washe1r Dynamic Viscosity Velocity before orifice Q lb·sec Q := 4·-� -4 Vl := _ min Jl := 2.34·10 ·---- Al f? Reynolds Number -1 Vl = 11.619•ft•sec p·Vl·dl 4 RE := Re := 2.952·10 Discharge coefficient from chart Jl Velocity of Waterjet Cn := .985 Pressure Force (Pl - P2) 2· I 4 \ p· 1-� ) -1 V2 := \ V2 = 730.327 •ft•sec Pf := p·Q ·V2 Cn PF := 12.626·lbf Q V3 := -l A2 V3 = 883.7 16•ft•sec D-1 d1 d2 B=d1/d2 P1 P2 den Velocity (Ws) Force (lbs) cr (psi) 0.375 0.005 0.013 3500 0 0.01 3 720.824 12.469 635043.95 0.375 0.010 0.027 3500 0 0.013 720.824 12.469 158761 .02 0.375 0.01 5 0.040 3500 0 0.013 720.825 12.469 70560.53 0.375 0.020 0.053 3500 0 0.013 720.827 12.469 39690.41 0.375 0.025 0.067 3500 0 0.013 I 720.831 12.469 25402.01 0.375 0.030 0.080 3500 0 0.013 I 720.839 12.469 17640.47 0.375 0.035 0.093 3500 0 0.013 720.852 12 .470 12960.57 0.375 0.040 0.107 3500 0 0.013 720.871 12.470 9923.20 0.375 0.045 0.120 3500 0 0.013 720.899 12.470 7840.86 0.375 0.050 0.133 3500 0 0.013 720.938 12.471 6351 .44 0.375 0.055 0.147 3500 0 0.013 720.991 12.472 5249.51 0.375 0.060 0.160 3500 0 0.013 ' 721 .061 12.473 441 1.47 0.375 0.065 0.173 3500 0 0.013 I 721 .150 12.41'5 3759.35 0.375 0.070 0.187 3500 0 0.013 721 .262 12.41'7 3241 .99 0.375 0.075 0.200 3500 0 0.013 721 .402 12.479 2824.68 d1 d2 B=d1/d2 P1 P2 den Velocity (Ws) Force (lbs) cr (psi) 0.375 0.040 0.107 2000 0 0.013 544.927 9.426 7501.24 0.375 0.040 0.107 2500 0 0.013 609.247 10.539 8386.64 0.375 0.040 0.107 3000 0 0.013 667.397 11.545 9187.10 0.375 0.040 0.107 3500 0 0.013 720.871 12.41'0 9923.20 0.375 0.040 0.107 4000 0 0.013 770.643 13.3�� 1 10608.35 0.375 0.040 0.107 4500 0 0.013 817.391 14.139 11251.86 0.375 0.040 0.107 5000 0 0.013 861 .606 14.904 11860.50 0.375 0.040 0.107 5500 0 0.013 903.660 15.632 12439.39 0.375 0.040 0.107 6000 0 0.013 943.842 16.327 12992.52 0.375 0.040 0.107 6500 0 0.013 982.381 16.994 13523.05 0.375 0.040 0.107 7000 0 0.013 101 9.465 17.635 14033.53 0.375 0.040 0.107 7500 0 0.013 1055.247 18.254 14526.08 0.375 0.040 0.107 8000 0 0.013 1089.854 18.853 15002.47 0.375 0.040 0.107 8500 0 0.013 1123.396 19.433 15464.20 0.375 0.040 0.107 9000 0 0.013 1155.965 19.996 15912.53 - 0.375 0.040 0.107 9500 0 0.013 1187.641 20.544 16348.57 - 0.375 0.040 0.107 10000 0 0.013 1218.494 21 .078 16773.28 - 0.375 0.005 0.013 20000 0 0.013 1723.100 29.807 151 8045.38 0.375 0.005 0.013 30000 0 0.013 21 1 0.357 36.506 1859218.30 0.375 0.005 0.013 40000 0 0.013 2436.831 42.153 2146840.37 0.375 0.005 0.013 50000 0 0.013 2724.460 47.129 2400240.50 D-2 Compressive Strength of Wood Perpendicular to Grain otl :=25 MPa From Waterjet Velocity Calculations Cross-Sectional Area of Orifice Diameter Pf := 12.626 d :=: 1 Shear Force Applied to Tree Branch From Nozzle ot2 :=-Pf ot2 := 110839.5EMPa Ac Cutting Force Needed to Cut Wood Perpendicular to Grain 2 otl \ - Pzl := 2· I Pzl = 1 N \ 100) Cutting Force Applied to Tree Branch From Nozzle lot2\2 Pz2:=2·1_, - Pz2 := 66.59 \woj N D-3 Test 1 (3500 psi) Velocity (m/s) Pressure Force (N) Pressure Force Required (N) 222.604 56.4 1.00 cr1 (Mpa) orifice diameter (mm) pressure (Mpa) 25 1.00 24.1 32 Depth of Cut (mm) Cutting rate (mm/s) Time for cut (sec) 1 0.68091 3294 1.46861 5767 2 0.2671 16871 3.743679666 3 0.15451 7659 6.471 752204 -- 4 0.104787825 9.543093408 5 0.077532236 12.897861 -- 6 0.06061 6049 16.497281 1 7 0.04922769 20.31377045 -- 8 0.041 1 0743 24.32650224 9 0.03506424 28.5190841 �� 10 0.0:3041528 32.87821162 -- 11 0.02:6743096 37.39282796 12 0.023779194 42.05356989 13 0.02134363 46.85238594 14 0.01931 1631 51.78226401 15 0.017594163 56.83703134 16 0.0161261 18 62.011 20391 -- 17 0.01485887 67.29987077 18 0.013755422 72.69860349 19 0.01278717 78.20338428 -- 20 0.01 1931672 83.81054805 21 0.01 1171096 89.51673517 22 0.010491104 95.31885252 23 0.009880052 101.214041 1 24 0.009328389 107.1 996488 25 0.008828213 113.2732074 26 0.008372936 119.4324128 27 0.007957025 125.6751083 28 0.007575799 131.9992698 -- 29 0.007225277 138.4029935 30 0.00690205 144.8844846 31 0.006603186 151 .4420477 32 0.006326148 158.0740779 33 0.006068732 164.779054 34 0.005829016 171.555531 35 0.005605314 178.4021 345 36 0.00!5396143 185.3175553 37 0.0052001 93 192.3005445 38 0.00501 6305 199.3499091 37 0.005200193 192.3005445 36 0.005396143 185.3175553 -- 35 0.005605314 178.4021345 -- 34 0.005829016 171.555531 33 0.006068732 164.779054 -- 32 0.006326148 158.0740779 31 0.006603186 151 .4420477 30 0.00690205 144.8844846 29 0.007225277 138.4029935 28 0.007575799 131 .9992698 - 27 0.007957025 125.6751083 26 0.008372936 119.4324128 25 0.008828213 113.2732074 24 0.009328389 107.1 996488 23 0.009880052 101.214041 1 22 0.010491 104 95.31 885252 21 0.01 1171096 89.51673517 20 0.01 1 931 672 83.81 054805 -- 19 0.01278717 78.20338428 -- 18 0.013755422 72.69860349 - 17 0.0'1 485887 67.29987077 -- 16 0.0161261 18 62.011 20391 15 0.017594163 56.83703134 - 14 0.01931 1631 51 .78226401 13 0.021 34363 46.85238594 12 0.023779194 42.05356989 11 0.026743096 37.39282796 10 0.03041 528 32.87821 162 -- 9 0.03506424 28.51908412 8 0.04110743 24.32650224 7 0.04922769 20.31377045 6 0.060616049 16.4972811 5 0.077532236 12.897861 4 0.104787825 9.543093408 3 0.15451 7659 6.471752204 - 2 0.2671 16871 3. 743679666 1 0.680913294 1.468615767 -- 6448.1 2839 1hr47min47sec Ti me for cut (sec) r=-.=-r;rnefor cut (sec) 1 250 ,---������ 200 '(!' Q) 150 s � '!:::: • 1::3 ...... ;.: Q) E i= 100 50 I :? 0 Ia:, I I I I �� -_, , I I i I I 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63 65 67 69 71 73 75 Depth of cut (mm) £L OL. L.9 tr9 �9 89 99 C:9 6tr 9tr 00 .--.(f) --- -- E Etr s E E 5(I) �E ov ::-:::s Q) 1§ (,) ...... 0') "-(IJ L.£ '0 ..c 0) ·B::::J - c u "B tr£ g. ::J Q (.) f �£ 82: 9C: ;:;;:; 6� 9� 0 m L. v (D � ""': (Y') "'! Cl c::i Cl Cl c::i Cl Cl (s;ww) a�J 6U!»Il:) D-4 D-5 MathCad Shear Analysis Sleeve Buckling Analysis Constants b :=4 t := .125 L:=l2 c := 1.375 cry := 80000 Equivalent length Le :=2-L Centroid (y_bar) b c b-e ··- t 2 2 A·dla+ A2·d2a·2 -- - A:=b·t A2 := ·t dla .·-- d2a :=t + ---· y_bar : ------2 2 2 A+ 2·A2 Eccentric loading e := 1.25 - y_bar M :=F·e Moment of Inertia (It) Calculation t · - b c dl :=y_bar- - yt · - -- -- 2 2 2 3 ·- b·t I.- - 12 Critical Slenderness Ratio (Lr_cr) L r.·-- {fi - =24.357 Lr_cr :=:n: �A r �cy{2.E Le Lr_cr = 84.59 =48.713 r ..../ Sigma Allowable Calculation (AISC Code) r :=2.+ ]_. -- L crcr:= cry· ! - Fs � FS = 1.859 3 8 Lr_cr�e 8 Lr_cre 3 ] [ 2-(�Lr_r cr- ,] [ ( f crcr crall:= crall= 35903.021 FS Compressive Stress F M ·(yt - y_bar) :- + = 12580.1 14258 a A+ 2A2 It a a 2 .:_ linkage Design Calculations Constants Pressure := 1200 Piston_dia := 2 Rod_dia := .625 A==2.8 348 F_piston :=A ·Pressure F_piston = 3401.7558 a_b_O := 1.195 a_close := .235 a_a_2 :=5 -c�o) Linkage System Geometry Solutilons c := 8 Effective moment crrm bO :=c·sin(a_b_O) c2 :- bO ----cos( a_a_2) c2 = 7.47015 Distance between pin centerlines b( a_b) := c ·sin( a_b) a_a( a_b) := 1.57 - a_b a2( a b) a_a2( a_b) := atan - a( a_b) := c ·cos( a_b) ( b(a_b) ) a_tot al( a_b) :=a( a_b) + a2( a_b) a_total(a_b_O) = 3.58717 a_total(a_close) == 15.01429 Stroke_Length := a_total( a_close) - a_total( a_b_O) Stroke_Length = 11.42712 Required minimum l'is1ton stroke length a_eff(a_b ) := a_a2( a_b) + a_a( a_b) F _piston ·.5 F( a_b) : Te nsile force applied to dogbones (theoretical) - sin( a_a2( a_b) ) · a b)) eff( a_b) )) Effective cutting moment Meff( a_b) := c ( (F( _ ·sin( a_ Meff( .7981) = 21089.10469 Meff( .7301) = 19422.51627 Meff( .6651) = 17 829.14354 Meff( .6041) = 16316.29097 Meff( .5461) = 14854.63716 Meff( .4911) = 13444.82261 Va lues used in Figure XX Meff( .4371) = 12037.46847 Meff( .3851) = 10661.08315 Meff( .333) = 9262.52632 Meff( .2841) = 7933.70696 Meff( .l9) = 5339.61086 Pin shear analysis (dogbone pim;) d :=.375 A.· --- 1t ·d 2 Tall := 80000 4 ll := .3 Coefficient ol' friction F( .437)·.5 T :- Pure shear ce�mponent A T· ·.5 T2 ;:_.;._;__ Torsional shear due te� rotational fr'iction (%J ) T_total := T + T2 T_total = 19104.42067 To tal shear stress Tall FS := FS = 4.18751 Fa ctor of SafE�ty --T_total 2 Tensile Stress (dogbanes) W:=.75 t := .25 Aeq :=(W-d)·t crall := 30000 F(.437)·.5 0 :- (J = 10176.66134 Tensile strE!ss Aeq crall FS := FS = 2.94792 Fa ctor of Safety (J Bearing Stress at all pin interfaces (dogbanes) F( .437) ·.5 crb := crb = 10176.66134 Bearing stress d·t crall FS := FS = 2.94792 Fa ctor of Safety crb Bearing Area Stress (linkage brac:ket inserts) t :=.5 : - F_ piston ·.5 crb crb = 9071.34879 Bearing stress d·t crall FS :=- FS = 3.30712 Fa ctor oiF S�Jfe ty crb Bearing Area Stress (sleeve shear pin) d := 1 t := .125 crall := 40000 F_piston ·.5 crb := crb = 13607.02318 Bearing :stress d·t crall FS := FS = 2.93966 Factor ol' Safety crb 3 Extension Arms b := .375 h := 1.375 d := 3.25 Ft( a_b) := F( a_b) ·cos( a_eff( a_b)) - b·h3 h · ,-_- I.-- c. M( a_b) := d ·F( a_b) ·sin( a_eff( a_b) ) 12 2 I=0.08 124 c = 0.6875 M( .437) = 4889.15423 Meff( .437) = 12034.841 17 M(a_b)·c Ft( a_b) a_b -- - cr( ) : - cr2(a_b ) :- Ft( .437 ) = 1173.81975 I b·h cr(.437 ) =41375.98288 cr2( .437) = -2276.4989 F( .437 ) = 1908.124 crt(a_b ) := cr(a_b ) +-cr2(a_b ) -Ft( .437) T : - crt(.437 ) = 43652.48178 2 T = 42285.92465 ·.188 .::4 Extension Arms b :=.375 h := 1.375 depth :=0 W:=O d :=3.25 Ft( a_b) := F( a_b) ·cos( a_eff( a_b)) - b·h3 h · ,_ I.-- c ·-- M( a_b) := d ·F( a_b) ·sin( a_eff( a_b)) 12 2 depth ·W 3 12 := It :=I- 12 M(.437) =4889.15423 12 It = 0.08124 c =0.6875 M(.437) =4889.15423 Meff( .437) = 12034.841 17 M(a_b)·c - Ft( a_b) cr(a_b ) : - -- cr2(a_b ) := Ft( .437) = -ll73.81975 It b·h-W·depth cr(.437 ) = 41375.98288 cr2( .437 ) = 227 6.4989 F( .437 ) = 1908.124 crt(a_b ) := cr(a_b ) + cr2(a_b ) crt(.437 ) = 43652.48178 4 Welded section b := .3 h :=.8 d := 1 Fl :=2900 cx_a( .437) = 1.133 3 · · - b·h ,_ h F ::=Fl sin( 1.13) I.- - c.-- M:=d·F F = 2622.79535 12 2 I=0.0128 c = 0.4 M =2622.79535 Ft :=Fl ·cos( l.l3) ,_ M ·c Ft cr.- - cr2:= - 1 b·h a = 81962.35466 cr2 51= 55.47268 crt:=a + cr2 crt = 87117.82734 5 Fr n.11 M·l l) M o-tJ Wd Sum of Moments Sum of Forces L "LM A = wd L. + W1 --M 1 = o 2 L. I.M =M!-. I +F'i-I L. I +WI.- 1. -Ml. = 0 1. ri r; 0 A 2 'LFy = W +F -l -- F = L. M.I =M.1+F L I. +WI.- 1 1- 'i-1 2 D-6 D-7 Meq and Keq calculations I ./ \ 11 := 43 12 := 46 13 := 46 14 := 46 15 := 46 16 := 42 17 := 42 18 := 39 := 0 10 := .076 ID PI OD A v M := 3.75 := 3.5 2 := .076 od1 idl A1 :=�{(od1?-(id1) ] VI := A, ·I! MI := P, ·Vl p2 3 := 3.25 := 2 2 := · od2 := .5 id2 A2 �-[ (od2) - ( id2) ] v2 A2 12 M2 := p2-V2 := 3.25 2 2 6 od3 id3 := 3 A3 := �{( od3) -(id3) ] v3 := A3 ·13 M3 := Pz-v3 E I := 120 ·to 2 2 6 od4 := 3 id4 := 2.875 A4 := �-[ ( od4) -(id4) ] v4 := A4 ·14 M4 := P2-v4 E2 := 120-10 od5 := 2.875 id5 := 2.75 As := � { ( ods? -(idsY] V5 := As ·Is Ms := p2·Vs p := 15 2 od6 := 2.75 id6 := 2.625 A6 := �-[ (od6Y-(id6) ] v6 := A6 ·16 M6 := P2-v6 M I = ·- n = oo \2 1' 2 · A ' A I od7 := 2.625 id7 := 2.5 A7 . 4.[ ( 7) - d 7 ) ] v7 - 7 .•7 M7 := P2-v7 - \' . od \4 _ fid 4 · = ( 6 \ 6 ) · 2 V '= A . l\11 = " .v I ·= .,. ) = . 2 · V . � " iii . �--� 17C:-� _ 1 n I '" - oil := ·- := · � r fnii \ 1' \ •g • �--' ' g • . �-g --� 8 A� · ( d ' a I 2 6 64 - s 4 l \ ��s) s) J s s ·s ( od7r - ( id7r 4 4 ( od r - ( id r ( odst - ( id5r 17 := n: . 64 o o id / n: . 4 4 n: . ·- ( od1t-(id 1 ) ( d2) - ( id2t ( d3t-( 3 1 := 1 := I n: . 1 := n . 1 := n: . 4 64 5 64 I .- 64 2 64 3 64 n:.( odst -( idst I 8 := p I := 15 p 2 := 15 p3 := 15 p4 := 15 p 5 := 15 p6 := 15 p7 := 15 p8 := 15 64 8 135 := := 227 := 269 := 3It := 350 LIS L1 := 43 L 2 := 9 L3 := L4 tst L5 L 6 L7 L18 long := 12 I = sub = 8 sub + + M + M + M + M + M + M long = := M1 M2 3 4 5 6 7 8 I I = x2 l (PI·i) + [ PI·(LI8-LI) · J section : = ·(3·11 - x) [[ 6 ·E I ·I I ] (z·E I ·I I ) ] . · · l · 1 2 · 2 p ·x2 sechon2 PI ( ir + [PI (LI8-LI) ·( 1) ] + [PI ·(LI8-LI) ·ti] + PI (ll) + 2 2 + (LI8-L2) . - ·x ·x --·x ·(3 ·1 - x) P ...... :__....:______::..__ [ 3 ·EI ·II E1 ·II ] [ EI ·11 l [ 2 ·EI ·II ] [ 6 ·E2 ·12 2 l [ 2 2 ·E2 ·12 ] 2 2 2 . · PI -(IIr + [P�·(LI8-Lt)·(1t) ] + [PI·(LI8-LI) ·1I] + PI·(ll) + p2 2 (LI8-Lz) ·(1z) [P2·(Lis-Lz) ·1z] sectlon3 .-- ·I ·I --·(1 ) ·(3·1 z - 1 ) + P · + · [[ 3.E l . I I E I .I I ] [ E, ·II l 2 [ 2 ·EI ·II ] 2 [ 6 ·E2 -12 2 · 2 l [ 2 2 ·E2 ·12 ] [ E2 ·12 ] 2 - .· · · · 1 · ·1 · 1 · - ·l sectwn4 ·- P� (IIr + [P� (LI8-LI) ( 1Y] + [P1 (L18-L1) IJ + P1 ( 1) + P2 2 + (L18-L2) (•zY + [Pz (Lis Lz) z] .- ·I ·I --·(1 ) ·(3 ·l - I ) P · -==-----_;__-c.___:::. [[[ 3·E1 ·11 E1 ·11 ] [ E1 ·I1 ] 2 [ 2·E1 ·I1 ] 2 [ 6·E2·I2 2 . 2 2 l [ 2 2·E2·I2 ] [ E2·I2 ] · l 3 · 2 · 1 · p · := PI ( i) + [PI (LI8-LI) ·(II) ] + [PI (LIS - L I) \] + PI ·( 1? + l 2 + (LIS - L z) (tz? + [ 2 ·(LIS - L z) IJ sectionS ·1 r ·1 · lz \ - 3 ·1 1 \ p . r 2 1 2 r. ( ( 2 - 2 2 1 .F T? .r .J � .J?. I 3 ·E ·I E ·I r E ·I - ·-R -, ·I ) ) I l - ·I l I LLL 1 1 i 1 J 1 1 J � ] -z 2 �z 2 J �2 �2 1 J L L rrr[ l 1 l Lf r · 1 2 1 2 i 2 p · 6 = PI ·(tl/ + [PI (LI8-Ll) ·( 1) ] + [pI ·(Lis-Lt) ·II] + PI ·( I) + l + . (LI8-Lz) ·( z) + [ 2 (Lis-Lz) ·lz] section : ·1 ·1 ·(1 y ·(3 ·1 - 1 ) p r lf [[[[ 3 ·E1 ·11 E1 ·11 l [ E1 ·11 ] 2 [ 2 ·EI ·11 ] 2 [6 ·E2 ·12 2 2 2 ] [ 2 2 ·E2 ·12 ] l E2 ·12 2 ·(11 [PI ·(LI8 � LI) ·(1�?] [PI (L - L ) ·I ·(1 Y i _2_ i \ . i . (Lts - Lz) ·(1z) [ p2 -(Lts - Lz) ·!2 section7 := ? + + · IS l I] ! + PI I + 2 3 _ + + 3 I I · 2 r · 2 r ·( 2 ·( 12 z) p2 2 · I E I _ � I 2 I 6 ·I ) E _ ·E · E · E ·E · .J ... ·E .J · .J · [[[[ I I l 1 l I · ! ] 1 l 1 2 2 1 [ 2 2 1 [ 2 2 [[ PI r l I 2 2 PI ·(llr + [PI ·(LIS - Ll) ·(11) ] + [PI ·(LI8-Ll) ·II] + PI ·(1I) + l 2 + (LIS -L2) ·(12Y + [ p 2 ·(LIS - Lz) ·I sectionS : = ·1 ·1 ·(1z) ·(3 ·1 - lz) pz. [[lr[[lr[ 3 ·E II·I E ! ·I l l [ E II·I ] 2 [ 2 ·E II·I ] 2 [ 6 ·E 22·I 2 l [ 2 ·E 22·I ] [ E 22·I 2 ,- - -�1- ,_./.! !.ULU - U.Ol l M 3 M 6 tot7 = 0.837 _ ::::0.09 3 _ ::::0.04 13 16 totS = 1.12 + tot18 := totl·M1 + tot2 ·M2 + tot3 ·M3 + tot4 ·M4 + totS ·M5 + tot6 ·M6 tot7 ·M7 + totS ·M8 Mass equivelant tot18 = 5.766 masseq := totl8 + 15 masseq = 20.766 stiff := ;:-r;:o::-;:r:-;::------,------=;::;------;::------=:------::------,----- l 1 2 1 2 P1 ·( ,r [ P1 ·(L18 - L1) ·( 1) ] [P1 ·(L18 - L1) ·l P1 ·(11/l l fl l 2 l _ p • (L18 - L 2) ·( 2) + [ P2 ·(L18 - L: + + \] 2 + · 2 + l ·( 2) -(3 · 2 12) + 2 3 ·E ·1 E1 ·11 E ·1 2 ·E -1 j l 6 ·E ·1 2 ·E ·1 E ·1 [r[[r[[L L 1 1 ] [ 1 1 ] [ 1 1 2 2 l [ 2 2 1J [ 2 2 stiff = 22.974 rad �.34l · stff w .- i ! masseq w, = 1.052 s 1.89 r1.5 1 I = I 0.622 f := --·w 0 I 2 ·11: f0 :::: s 0.413 't := 3 .:..::: 0. 56 w, �:��� j' 't = 6 D-8 Dynamic Reponse restart ; [ > > with (plots) ; [animate, animate3d, animatecurve, changecoords, complexplot, complexplot3d, conformal, contowplot, contowplot3d, coordplot, coordp lot3d, cylindetplot, densityplot, display, displa_r3d, fie!dplot,fieldplot3d, gradplot, gradplot3d, implicitplot, implicitplot3d, inequa!, listcontplot, listcontplot3d, listdensityplot, listplot, listplot3d, loglogplot, logplot, matrixplot, odeplot, pareto, pointplot, pointp!ot3d, polarp!ot, polygonplot,pol ygonplot3d, polyhedra_supported, polyhedraplot, replot, rootlocus, semilogplot, setoptions, setoptions3d, spacecurve, sparsematrixplot, sphereplot, surjdata , textplot, textplot3d, tubeplot] w: =2 . 531; lF := 2.531 c:=.13; c := .13 x:=exp (-c*w*t)*sin (sqrt (1-cA2)*w*t ); ( . I) · · · x:=e - 32903 sm( 2.509 521918 t) v:=diff (x, t); v := -.32903 e1-.32903 n sin( 2.509521918 t) + 2.509521918 e(-.32903 t) cos( 2.509521918 t) a:=diff (v, t); a := -6. 1 89439516 e(-.32903 n sin( 2.509521918 t) - 1.651415993 ,e<--32903 n cos( 2.509521918 t) plot (x, t=1 20); > •• 0.4 ,.-\ I1\ \ I \ I I i I 0.2 I I I \ (\ I I I \ / ' r·, 11 4 8 I 6\\ I I ' \\\ /'1 cv--- , .,•<::::::;::; 12 d.:::.;::,._,�,...._..=...._._...._,_...... ,J...... _..__.__._...J 14 1e 18 20 0 '---' I \ I I -0.2 I \\/ -0.4 \ I II I, I I I v I Page 1 plot (a, t=1 20); > .. 3 2 I 18 20 plot (v, t=1 20); > .. '/\' i ' I I I 0.8 I \ \ 0.6 I II 0.4 r ' 'I \ 0.2 I I \ I 4 \ 6 I \� ' ��" . . 1J�'""'=""'""--"14...-.=�-...J16��-1.J.._8...... _�.20 0 � I -0.2 ·� -0.4 \I v \I\ I \! \"// -0.6 \ ! -0.8 J -1 -1 .2 -1.4 -1 .6 Page 2 J�ppendix 1� E-mail Responses / http:!/lw 1 fd.hotmaiLcornlcgi-bin/getmsg?... MSG9 19073635.165721 &start= 77582&len=20: t Dictionary Read Message RELATED: design project Thesaurus From : Josef_Kaiser@ingerrand .com Save Address Block Sender 'I'o : ryedog_1@hotmail . com CC : Suzanne_Perry@ingerrand .com Subj ect : Antwort : waterj et cutting Date : Mon , 25 Jan 1999 09 :44:28 +0100 Dear Mr . Ra fter , I forwarded your request to Suzanne Perry of our USA manu facturing facility in Baxter Springs , Kansas . F'or info : To cut wood 3 inch thickness abrasive cutting is needed . The edge r·esul ts wi ll not be so wonderful . To de termine the parameters a test cut would be needed to obtain cutting speed . The parameters will be something like 50. 000 psi , 0.010" water ori fice , 0.030" focusing tube size , 0.6 lb abras ive flow. Best regards Josef Kaiser Product Manager Ryan Ra fter An: info@waterj et . irautomation . com Kopie : (Bl indkopie : Josef Kaiser/sf/ esa/ ingerrand) Thema : waterj et cutting Hello, I am a senior Mechanical EngineE!ring student at Northeastern Univesity. I am currently working on my design pro:j ec:t where I need to cut through a piece of hard wood (maybe pine ) that is 3" in diameter . I was wondering if you could give me any suggestions to the pressure , flowrate , and/or velocity I need to obtain to cut through this . Also , if abrasives are needed . Thank you very much for your time , Ryan Ra fter l of Z 6/2/99 1:14 AM http://lw 1 fd.hotmail.com/cgi-bin/getmsg? ...MSG9 19073635.1 65727&start=8090 1 &len= 13( Dictionary Read Message RELATED: design project Thesaurus From : Joe Rybak Ryan , Waterj etting is not a very good procedure for cutt ing wood that thick a contact cutting method will yield a better qua lity cut and be more cost effective . Joe Rybak Senior Sales Manager Ryan Ra fter wrote: > Hello, > > I am a senior Mechanical Engineering student at No rtheastern > Univesity. I am currently working on my de sign proj ect where I need to > cut through a piece of hard wood (maybe pine) that is 3" in diameter . > I was wondering if you could give me any suggest ions to the > pressure , flowrate , and/or ve locity I need to obtain to cut through > this . Also , if abrasives are needed . > > Thank you very much for your time , > > Ryan Ra fter Mov ! (Move to Selected Folder) [ �. �..... E] Air Tickets I Buy Music I Downloads I Entertainment I Free Games I Yollow Pages t'"'''� , , ''"'' rs::: � the 1 I I.... ::. ��E.�!�.J © 1999 Microsoft Corporation. All rights reserved. Terms of service l of 1 6/2/99 1:14 Al\" http:l/lw 1 fd.hotmail.com/cgi.-bin/getmsg?... MSG9 19073635.1 65733&start=822 1 O&len= 19: Dictionary Read Message RELATED: design project Thesaurus FJ�om : "Jerry DeSantis" Dear Mr . Ra fter , Thank you for your interest in Jetech products . The price for a bare shaft (only the pump ) pump is $35,500 .00. A complete system including a diesel engine , filters , control panel , gauges and required operating valves is in the $75, 000 to $110,000.00 range . The model number of the complete system using the 250H3 -UH pump is 250H3 -UHDS . The 250 =, hp range , H = crank-end style, 3 = triplex ( three plungers/pump ing elements, UH = ultra-high pressure range (up to 40, 000 psi) , D = Diesel engine driven and the S = fabricated steel skid . The systems we ights in the area of 7,500 pounds . Good luck with your project G. J. De Santis Jetech Inc . -----Original Me ssage----- From : Ryan Rafter >Hello, > >I am a Mechanical Engineering student at Northeastern University. I am >currently working on my design proj,ect . I was just wondering on the >price of your 250H3 -UH Ultra-High Pressure Pump . > >Thank you for your time , > >Ryan Rafter > > Mo o Se cted.Fo r Move To !' ( ve t le lder) 6 I of 2 612199 1:14 AM http:lllw 1 fd.hotmail.corn!cgi·bin/getmsg? ...msg=M SG919193495. 9&start= 1 00598&len= 1 0' Dictionary Read Message RELATED: design project Thesaurus From : pepall@idirect .com (Lynn Pepall) Save Address JBlock Sender To : ryedog_1 @hotmail . com Subj ect : high pressure nozzles Date : Tue , 16 Feb 1999 14 :27 :26 -0500 (EST) Att . Ryan Ra fter .039= 1 mm 0 degree spray , my flow chart tells me 4 9allons per minute @ 3500 psi is a .047 orfice diameter in inches . Pricin9 would be $52 .00 c/w 1/4 npt holder and tungsten carbide insert . if you have any questions call me at 905-889-5237 or fax 905-889-4818 John Millman IMS ltd Move To (Move to Selected Folder) El ------·----- Air Tickets I Buy Music I Downloads I Entertainment I Free Games 1 Yellow Pages :------� ! S�ar?�J © 1999 Microsoft Corporation. All rights reserved. Terms of service I of 1 612199 1:15 AM http://lw 1 fd.hotmail.com/cgi-binlgetmsg? ...sg=MSG9 19266441 . 12&start= 1 0391 8&len=38: Dictionary Read Message RELATED: design project Thesaurus FJ�om : "George Savanick" Mr Ra fter; I have the following comments : 1. Waterjets are not used commerc ially to cut trees , probably because the fibrous structure of the wood tends to dissipate the jet's energy . Wood can be cut with a waterj et but thick cuts tend to be inefficient . 2 .. A 3500 psi , 4gpm waterj et wi ll not cut through a 3-inch limb in a single pass . 3. A jet wi th a pressure and flow rate sufficient to cut through a three-inch diameter limb in a single pass would not be practical for manual use by landscapers. The reaction force would be too hi9h and the size of the pump required would preclude easy portability . 4. You need to de sign a waterj et cutting head that can enter into the kerf cut by the jet . This will ma intain a constant stand off di stance ,so that mu ltiple cuts can be made to get through the limb 4.1 This concept is used to cut deep (15 feet ) , long (25 feet ) kerfs in granite with a waterj et . A commerc ial machine to do this is manufactured by a firm in Wocherster , Massachusetts . If you are interested I can mail you a cipy of our newsletter , Jetnews , that briefly describes this machine . I hope this is useful to you . George Savanick gsavanik@minn .net > Hello, > > My name is Ryan Rafter . I got your email address from Rhonda > Eckhoff, she said you may be of some assistance . I <� currently a > senior Mechanical Engineering student at Northeaseastern University . I > am working on my design project in which we are designing a device to > cut tree limbs that are three inches in diameter with a waterj et cutting > device . This device would be marketed to professional landscaping > companies or maybe groundkeeping crews at golf courses . > We have done extensive research on waterj et cutting and we do not > feel that obtaining the high pressures for waterj et cutting is a > feasible solution for somebody wi shing to prune tree limbs that are 3 > inches in diameter . We have gone away from using abrasives because the > abras ive ma terial may be hazardous to somebodies trees and lawns . > We are currently doing some initial calculations to figure out if a > pressure washer with a pressure of 3500 psi and a flow rate of 4 gal .min > attached with a high pressure noz zle with an orifice diameter of 1mm > will 1 of 2 612199 1:15 AM http://lw 1 fd.hotmail.com/cgi-binlgetmsg?... sg=MSG9 1 9266441 . 12&start= 1 0391 8&len=38: > I would like to thank you in advance for your time . > > > Ryan Ra fter > Senior Mechanical Engineer Student > Northeastern University > > you can also reach me at : > rrafter@lynx .dac .neu . edu > > > ------>Get Your Private , Free Email at http://www .hotmail.com > __ M I. M()'IE3:ro ; ( ove to S�!edt�d Fold�r) [T] Air Tickets 1 Buy Music 1 Downloads 1 Entertainment I Free Games I Yellow Pages :.....------"1j_ sea�1 J © 1999 Microsoft Corporation. All rights reserved. Terms of s1�rvice L of 2 612199 1:15 AM http:/llwl fd.hotmail.com/cgi-bin!getmsg? ...sg=MSG9 1 9352943.1 9&start= 1 1 2779&len=l l Dictionary Read Message RELATED: design project Thesaurus From : pepall@idirect . com (Lynn Pepall) Save Addres1; Block Sender To : Ryan Ra fter Thank you for your request for information . . 039 = 1 mm 0 Degree Spray My flow chart tells me 4 USGPM @ 3500 PSI is a .047 Ori face Dia Inch . Complete wi th 1/4" NPT holder and tungsten carbide insert $ 52 .00 Each Canadian Funds Plus Taxes Thanks , John Mi lllman PH# 905-889-5237 FAX 905-889-4818 Air Tickets I Buy Music I Downloads I Entertainment I Free Games 1 Yellow Pages ;...... ------·------' ( Search j © "1999 Microsoft Corporation. All rights reserved. Terms of sorvice 612199 1:16AM J�ppendix F F-1 Instron Data F-2 Accelerometer Damping Test J () 0 . ' !"; ' �t ' . ; .. / ' . -::..-�-'.····.·�.--�=� Appendix G Part Drawings As sembly SHEAR_PUMP contains : 1 Sub-Assembly NE\"l"PISTON_OPEN (Piston Sub-Assembly) 1 Sub-Assembly ENERPAC PUMP (Actual ly TR-Engineering Hand Pump ) 1 Part TUBE (Hydraulic Tubing ) 1 Part Fitting (Hydraulic Pipe Fitting) Sub-Assembly NEWPISTON_OPEN contains : 1 Sub-As semb ly PRO __ SHEl\.RS_OPEN 1 Part NEW__ PISTON (Prince 2" Bore Hydraulic Piston) 1 Part SHEAR_BRACKET 1 Part NUT 1 Part SLEEVE-OPEN 1 Part BOLT 1 Part CLIP 1 Part DOGBONE1 1 Part DOGBONE2 Sub-Assembly PRO_SHEARS_OPEN contains : 1 Part PRO_HOOK 1 Part PRO_BLADE 1 Part Extension Arm Blade 1 Part Extension Arm Hook Summary of parts for assembly SHEAR_PUMP : 1 Part PRO_HOOK 1 Part PRO_BLADE 1 Part CHANNEL_BLADE 1 Part CHANNEL_HOOK 1 Part NEW_PISTON 1 Part SHEAR_BRACKET 1 Part NUT 1 Part SLEEVE-OPEN 1 Part BOLT 1 Part CLIP 1 Part DOGBONE1 1 Part DOGBONE2 1 Part TR Engineering Hand Pump 1 Part Hydraulic Tubing 1 Part Hydraulic Pipe Fitting I _.I IEC3 l I I I 10.0I 0 ---1 r w . 25-rtJ . 500 R.7 5 L 0 L / L I ) � 2.0/I 0 . 00 r- I. 6 0 4� 0 . 1 4 l 00I. 0 1 . 00 I L 7 0 jr- 50 � l � 2.00 3.3 7 - rs- I - t I I �ICJ I I D I I 3 7 5 � 1 �.7 5 5. 0 0 5. 75 I ) C5 : � 1-I Ji 40. 00 XX ± I XXX . ± 0I . .005 Tree Pru ning Device Desig n Team R 0 Sleeve SCALE jOS/I 12/991 Ryan1 Rafter l 0. 2 0 0 ' I IECJ Dl . . -· r---I ····1.. 6 El-- . \ . 0 R. I I e>l I-s- �.. 56 TYP 375 Q Q 2 5 3 7 5 375 j.\ 3. 2 5 2 . 7 5 � v-- R . \25 R � X 8. ...._ � 25 7. 4 7 0 - 2 2 2 I- S I i p Fit for . ')/[:: Pin I I I . I ) / ) � t ki V _J SCALE so� 1"" � . 75 XX ±. I 0. 50 0 XXX R 0 Tree Pruning Device Design Team . 001 Dogbone I Break al.l 0 edges Ryan Rafter I) Material: Alu minum -T6 I 104/20/99 1 I 6 06 1 I I I I UH "'" '"" ' I . I I I 06 I I 1-El-- . . 56 3 7 5 - R. 3 7 5 .25 TYP .375 11' " 50 I 3.25 R. 2 5 I � I R.2 5 7' 4 7 0 8.2 2 .50 4X � � ;so ; " Fit for oo � Pin 2 2 SCALE 0.500 X X . 75 1 � . I XXX ± ± 0I .00 Tree Pru ning Device Des ign Team R . 0 Dogbone 2 I) I I R yanI R after I Materi al: Alum inum 60 6 l T6 1 B rea k all e dge s 1 04/C0 /99 1 I I I _1 .20 SCALE 1.2 5 IE3 c:::. IE:J c:::. l 1.4 20 0 I r :.,. _ _,_, · . - (W [ ..1-S� . � J (!_ '" I (� T{! ,; � .. - - W1 .. . .. L_I. 794 . . I� IGJ1.4 2 I RYAN I-E=3----- 7. 0 0 RYtAN j . XX ± . 0 I XXX ± .001 Tree Pruning Dev ice Des ign Team R ± . 0 I Extension Arm - Blade Ryan Rafter I) Mater ial: Steel SCALE 0.500 ---- I r-- --- I �---- 1.000 a-1 3 220 ---�, 3 [ ., � ,3 6 , ' 4 SCALE . 375 0. 500 S E C T 1 0 N A - A 8 I r t . 30 0 I I 2 X I 3 U NC .855 Deep 680 across f I at s XX ± . 0 I ¢. XXX ± .005 Tree Pruning Device Design 92 R ± 0 I ¢.7 80 +.000 . New Bolt .005 - R y a n R a f t e r I) Material: Steel I I ¢.4375 � .8875 � XX ± . 0 I .005 Tap for #1/2 X 1 3 UNC XXX ± Tree Pruning Device Desig n Team R . 0 I L ± Custo m Nut Ryan Rafter 3 25 1�--'----- r- 1 Diame ter I 2 I I � A . 781 (25/32 ) .505 [ I 7 1.2 50 R.6 . 6 9 -j . 38 -=: A · _j_ "� I -r---�- -- I 1 ----.6; I 0 0 2.� 0 0 � � 25 . lJd� . 1 _L_ X X . 0 I Dr ill and Tap for 3/8 - 16 .005 RXXX ± . 0 I Tree Pr un1ng Dev ice Design Team 1.0 0 Deep Shear Bra cket 2 Places SCALE 0.500 04/22/99 1 Ryan Rafter I) Mater ial: Stee I --- - I I R-R SCALE 0.750 R ¢2.7 5 T h r u /l. ta S. H.C. S. �Dr i I I p for I I 4-2 0 / � 12X-Dr iII Thru /l. tap for #8 S H.C.S 0 -=+--625 . Tree Prun1ng Device Desig n � Tr ipod Fixture SCALE 0.500 Garth Baker - I I I I o jf or #8 S.H.C.S 1.0 00 1·@9J;;:I 4X-( 'Rore . I 2 , SCALE I. 25 000 . 4 5o X . I 1 1I I 0 -- - --.-w o-o 1 =t_ r [Q Rl . 250 . 25 I I � I I I I t ¢ .250 i R.253 SCALE 0. 500 / I.00 368 265 ltr�-. .544 tJ� D 9 5. 0 0° RI r-L 2.661 R. I 2 5 _j Tree Pruning Device Design Tr ipod Leg Bracket 05/01/99 Garth Baker --r- I I I ART 1T I� 6.0 0 REV. AUTHOR IZED CHANGED DATE �-Ji- g q .50 �1�<3- �3�.00 I I I 1 -1 2.50 l ] 5.0 0 r ] � O t� . 3 7 5 E>l �[<33--- . 400 SCALE 0.375 I . 5 ¢ .28 1<3 �:>1 I 9 1I S I- 2 ll .·62s2 -H � 1- I '- [ sol � ¢ . 188 THRU 5 5 I- I L�. 2 SCALE 0. 375 I l A=.50 NORTHEASTERN UN IVERS ITY TOLERANCES: Tree Pruning D evice Team SCALE 0.375 . X : ± I 00 .XX:± .010 . X X X : ±. 00 5 Bottom Fixture-lnstron ALL DIMENS. IONS ARE IN INCHES NG jf ma ter i a I A TIJRAYH REV A SIZE I # PART SCALE PAGE I OF I # I 3 14I -99 l T I ARl n I 1) I � REV. AUTHOR I ZED CHANGED DATE 8.0 0 SCALE _ � o.25o I 13-8-99 1I -� 3 .43 r-- I . ·� 1- I r o DO o � 1.2 5 rl, .63 y.; . THRU �-�-c . 188 .40 50 .375 [ 5. 2 5 • • m -----::J - I IIII I I t 1- SCALE 0.250 SCALE 0.250 .50 . [ 6 . 50 . 75 Ir- ==1 r- �4.0 0HI r-- THRU 2. 50 56 1 I' yj. M NORTHEASTERN UN IVERS ITY TOLERANCES: Tree Pruning D evice Tea m .X :± .IOO SCALE .XX:± .010 � 0.250 . XXX : ± . 005 L ¢ . 88 c I BORE Top lnstron Fixture / ALL DIMENS IONS ARE IN INCHES .25 DEEP D R A I N G ma ter i a I A . .. I REV A . # SIZE W ·· .. . .. #·· ______l PART # SCALE PAG E I OF I I I 3-1 6-99 J I I