DECEMBER 5, 2018

FREEDOM CONCEPTS DRIVE MODE FINAL REPORT

PREPARED FOR:

COLIN BOCK, FREEDOM CONCEPTS

JIM SYKES, P. ENG., E.I.R., ADVISOR

FACULTY OF ENGINEERING

MECH 4860 – ENGINEERING DESIGN

TEAM 11 JEREMY DRACHUK IAIN FRIESEN JORDAN HOFER JOSH LINSANGAN SCOTT VERCAIGNE

Letter of Transmittal

December 5th, 2018

Colin Bock Freedom Concepts 2087 Plessis Rd Winnipeg, MB, R3W 1S3 [email protected]

MECH 4860 – Team 11 University of Manitoba 66 Chancellors Circle Winnipeg, MB, R3T 2N2

Subject: Letter of Transmittal

Dear Colin Bock,

Our team is pleased to submit to you our final design report for the Drive Mode Mechanism for Freedom Concepts Inc., marking the completion of phase one of the project.

This report will be followed up with the phase two beginning in January 2019, during which our design team will validate the Drive Mode Mechanism through prototyping and testing.

If you have any questions, please feel free to contact any of the team members signed below.

Sincerely, Team 11

Jeremy Drachuk Joshua Linsangan Scott Vercaigne

_ Jordan Hofer Iain Friesen

Cc: Jim Sykes

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Executive Summary

This report marks the completion of phase one (design) of the Drive Mode Mechanism project submitted by Freedom Concepts Inc. for the MECH 4860 – Engineering Design course at the University of Manitoba. The second phase (prototype) will begin in January 2019 and will be completed in April 2019. Freedom Concepts Inc. is a Winnipeg based company that designs and manufactures adaptive tricycles and mobility devices for people living with disabilities. The company has tasked the student design team with the development of a tool-free mechanism to accomplish two separate drive modes for the rider ( and direct drive) and that is compatible with all current tricycle models. The current mechanism being used on the tricycles relies on frictional contact between four set screws and a standard freewheel to toggle between the two modes. Although functional, actuation requires the use of a tool and has proven too cumbersome for the average caregiver. The design team conceptualized a two-way ratchet mechanism capable of supporting a freewheel and direct drive mode with a single switch actuation. This concept was developed through research, concept development, and feedback from the client and the course advisor. The mechanism consists almost entirely of laser cut sheet metal and off-the-shelf components from McMaster-Carr® to reduce low-volume production costs and facilitate design changes in the prototyping phase. The estimated cost of the prototype design is $133.99. To meet the requirements set by the client, the design features two spring loaded pawls, one of which can be rotated away or toward an internal profile using a switch to support the freewheel or direct drive modes. The sprocket can be easily interchanged with any of the 18, 22 or 26-tooth variations to deliver all three pedaling difficulties that a customer may order. To maximize the lifespan of the device, the design is supported by a full stainless-steel construction, sealed bearings and maintenance plan. Included with the final design is a detailed installation procedure, bill of materials, cost breakdown, preliminary failure modes and effects analysis, and a complete package of preliminary drawings including all three custom sprocket sizes. These deliverables fulfill all requirements of the project as established by Freedom Concepts. An alternative internal tooth profile is also included and will be tested in the prototyping phase. The intuitive and easily actuated toggle switch will improve the user experience and encourage the use of the freewheel and direct drive modes as intended by Freedom Concepts.

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Table of Contents

List of Figures ...... iv List of Tables ...... iv 1.0 Introduction ...... 1 1.1 Background ...... 1 1.2 Objectives ...... 2 1.3 Project Timeline ...... 3 1.4 Target Specifications ...... 3 1.4.1 Client Needs ...... 3 1.4.2 Technical Specifications ...... 4 1.5 Constraints and Limitations ...... 4 1.6 Concept Development Summary ...... 5 2.0 Detailed Design ...... 7 2.1 Sprocket Design ...... 9 2.2 Pawl Design ...... 11 2.3 Toggle Mechanism ...... 12 2.4 Material Considerations ...... 14 3.0 Design Summary ...... 15 3.1 Preliminary Failure Modes and Effects Analysis ...... 15 3.2 Maintenance ...... 16 3.3 Assembly Procedure ...... 17 Pawl Disc Assembly: ...... 17 Sprocket Assembly: ...... 19 Installation Procedure: ...... 20 3.4 Cost Summary ...... 21 4.0 Conclusion ...... 22 5.0 References ...... 23 Appendix A – Concept Development ...... A-1 Appendix B – Stress Analysis ...... B-1 Appendix C – Preliminary Failure Modes and Effects Analysis ...... C-1 Appendix D – Bill of Materials...... D-1 Appendix E – Preliminary Engineering Drawings ...... E-1

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List of Figures

Figure 1. Present method of operation on tricycle ...... 2 Figure 2. Project timeline ...... 3 Figure 3. Two-Way Ratchet concept ...... 6 Figure 4. Teeth Engagement concept ...... 6 Figure 5. Two-Way Ratchet exploded view ...... 8 Figure 6. Design mechanism - a) freewheel mode b) fixed drive mode ...... 9 Figure 7. Interchangeable sprocket designs: a) triangle tooth design b) gear tooth design ...... 9 Figure 8. Sprocket design projected from standard tooth profiles ...... 10 Figure 9. 26, 22, 18-tooth sprocket options ...... 10 Figure 10. Pawl and gear design in a typical ratchet ...... 11 Figure 11. Design mechanism - a) Freewheel mode b) Direct drive mode ...... 12 Figure 12. Standard freewheel pawl design ...... 12 Figure 13. Toggle assembly ...... 13 Figure 14. Pawl case securing mechanism ...... 13 Figure 15. Complete assembly - switch side ...... 14 Figure 16. Pawl replacement ...... 16 Figure 17. Pawl Disc assembly sequence – Step 1 ...... 17 Figure 18. Pawl Disc assembly sequence – Step 2 ...... 17 Figure 19. Pawl Disc assembly sequence – Step 3 ...... 17 Figure 20. Pawl Disc assembly sequence – Step 4 ...... 18 Figure 21. Pawl Disc assembly sequence – Step 5 ...... 18 Figure 22. Pawl Disc assembly sequence – Step 6 ...... 18 Figure 23. Sprocket assembly sequence – Step 1 ...... 19 Figure 24. Sprocket assembly sequence – Step 2 ...... 19 Figure 25. Sprocket assembly sequence – Step 3 ...... 19 Figure 26. Sprocket assembly sequence – Step 4 ...... 19 Figure 27. Installation sequence – Step 1 ...... 20 Figure 28. Installation sequence – Step 2 ...... 20

List of Tables

TABLE I. TECHNICAL SPECIFICATIONS ...... 4 TABLE II. CONSTRAINTS ...... 5 TABLE III. SUITABLE MATERIALS FOR EACH MACHINED PART...... 15 TABLE IV. TOP FIVE RISKS ...... 15 TABLE V. COST SUMMARY ...... 21

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1.0 Introduction

The Drive Mode Mechanism project put forward by Freedom Concepts Inc. was formerly identified as the “On/Off Mechanism”. The system disengages the freewheel capability of the standard freewheel sprocket Freedom Concepts currently installs on their tricycles. Their current system is inconvenient to actuate, so Freedom Concepts has asked the team for the following: Develop and design a mechanism to improve the current method of switching between freewheel and direct drive for the users of the tricycle, while considering device features such as manufacturability, intuitiveness, and ease of use. This report provides a definition of the project, a review of the concept selection, and details of the final design. A preliminary failure modes and effects analysis (PFMEA), detailed installation and maintenance procedures, bill of materials (BOM), preliminary drawings, cost breakdown, and assembly instructions are included. 1.1 Background

Freedom Concepts Inc. is a sales and manufacturing company focused on designing and developing adaptive tricycles for individuals living with disabilities, directed towards exercise, rehabilitation, and recreational purposes. Freedom Concepts specializes in fully customizing their tricycles for every individual to provide a personalized fit for the rider. The adaptive tricycles are also used in rehabilitation centers and institutions, resulting in use by multiple operators. A direct drive mode is often desired during exercise or rehabilitation purposes, during which the pedals rotate with the movement of the tricycle. Alternatively, the tricycle may be used in freewheel mode, during which the pedals do not rotate along with the forward movement of the tricycle. Freedom Concepts developed a design (Figure 1) that allows the rider’s caregiver to switch between direct drive and freewheel without needing to switch tricycles or components. This feature offers caregivers the option to switch from direct drive to freewheel when the rider is fatigued from pedaling. The design is made of a threaded shaft hub welded to a laser cut plate holding four setscrews (Figure 1). The design is actuated by advancing the setscrews until all four setscrews contact the freewheel, engaging the direct drive mode.

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Figure 1. Present method of operation on tricycle

Disadvantages of the existing mechanism: 1. Non-ergonomic – To engage the device, the caregiver needs to bend down and reach behind the rear steer tube of the tricycle (Figure 1). Access to all four setscrews is limited by the rear steer tube requiring movement of the tricycle to access the fourth screw. With four setscrews to turn, the caregiver will be in this position for an extended period. 2. Tool dependent – To switch modes, the caregiver is required to carry a hex key to tighten the screws onto the freewheel. 3. Unintuitive – Turning the four setscrews to switch between drive modes may not be obvious to the caregiver unless given detailed instructions. 1.2 Objectives

The objective of this project is to design a drive mode mechanism which meets all the client’s needs. The following deliverables are requested by Freedom Concepts: 1. CAD model 2. Preliminary failure modes and effects analysis (PFMEA) 3. Bill of materials 4. Preliminary drawings (Appendix E) 5. Prototype (winter term, 2019)

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1.3 Project Timeline

A high-level visual timeline (Figure 2) displays the course deliverables, major milestones and status of the project. The phase two portion of the academic course is a new addition to the mechanical engineering program, and the details and deliverables have yet to be established.

Figure 2. Project timeline

1.4 Target Specifications

1.4.1 Client Needs The client’s needs were identified from the description of the present method of operation and input from the client. The needs are divided in two categories: Operation: - Tool-free operation - Simple to use - Reliable - Intuitive and user friendly - Safe for operators and users Manufacturing: - Inexpensive - Can be manufacturing over-seas - Compatible with Freedom Concepts’ product line

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Through analytic techniques (Appendix A) “Actuate without use of tools,” “Time Required to Actuate” and “Withstands Maximum Torque from Chain” were established as the key criteria used for screening and selecting the most fitting concept. 1.4.2 Technical Specifications Freedom Concepts has provided a set of specifications (Table I) the design must meet to ensure the design can be fitted to any of their tricycles. TABLE I. TECHNICAL SPECIFICATIONS

Specification ½” chain pitch A drive ratio of 1:1 to 1:1.5 5/8” shaft 250 lb maximum rider weight

1.5 Constraints and Limitations

A set of assumptions have been made, based on the working environment of the design and needs stated by the client: 1. The tricycle will not be subjected to extreme loads 2. The device will be built from common engineering materials. 3. Manufacturing and assembly will be completed offsite or at Freedom Concepts. 4. The device will not be removed for any reason other than maintenance or replacement as necessary. The constraints for this project have been developed from the needs and metrics identified for the project (Table II).

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TABLE II. CONSTRAINTS

No Constraint Implications and Analysis 1 Must interface with the Compatible with the standard 5/8” axle size used across standard rear axle size all Freedom Concepts products 2 Must engage and disengage No special instructions or tools are necessary for the without tools operation of the device. 3 Able to withstand the Supports a maximum load applied by a 250 lb rider. maximum expected force from the rider. 4 Avoid interference with the The device will not physically interfere with the rear rear steer mechanism. steer mechanism at any point of operation. 5 Can be adapted to the Compatible with the 18, 22, and 26-tooth sprocket sizes. specified drive ratios 6 Sprocket is compatible with Compatible with a 1/8" width by 1/2” chain pitch used the standard chain size by Freedom Concepts. 7 Ensures the safety of the The device must not cause harm or cause any other rider and operator at all components of the bicycle to cause harm to the rider or times. operator during engagement, disengagement, and normal use under all ride settings and pedal power variations. 8 Compatible with a chain Compatible with chain guards used by Freedom guard Concepts with little to no modification of the chain guard 9 Must manually toggle The device will only toggle between drive modes with between two riding modes. input from the operator.

1.6 Concept Development Summary

A total of 13 preliminary concepts were developed based on the primary functional requirements of unidirectional rotation, two-way locking, and actuation. To develop these concepts, literature in which several different mechanical locking devices are detailed were consulted [1] [2]. Additional research included patents [3] [4] and resources on commercial bicycle components [5] [6] [7]. Each preliminary concept was assessed on six criteria based on the customer needs. The top four concepts were further developed, at which time they were presented to the client. With feedback from the client, the Two-Way Ratchet (Figure 3) and Teeth Engagement (Figure 4) concepts were agreed upon to develop further.

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Figure 3. Two-Way Ratchet concept

Figure 4. Teeth Engagement concept

However, further research into the Teeth Engagement concept showed that that the required holes in the freewheel sprocket were not readily available for all required sprocket sizes [8]. Further development was ceased, and the design was replaced with the similar Flanged Freewheel design following input from the client. During the development phase for the Flanged Freewheel design, it was determined that machining costs would likely be expensive for the Splined Sprocket shaft seen in Figure 5. To solve this a freehub was investigated, however, the cost of a single freehub varied from $50 to $80 [9].

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Figure 5. Flanged Freewheel concept

With advancements to the Two-Way Ratchet including the implementation of standards parts and the use of laser cut components, the Two-Way ratchet became a more economical alternative to the Flanged Freewheel design. Therefore, the team decided to only pursue the Two-Way Ratchet. Details of the concept development process are included in Appendix A.

2.0 Detailed Design

Developments to the Two-Way Ratchet design following the concept development phase include an improved design of the pawls, pawl springs, and the tooth profile of the internal gear. The concept was designed to be economical in low volumes using commercially available parts and hardware, as well as laser cut components. The Two-Way Ratchet (Figure 5) consists of two main subassemblies that are only in contact via the pawls. The first subassembly, consisting of the sprocket hub, bearing, retaining ring, sprocket, spacer and three spring pins, is free to rotate on the 5/8” shaft through the bearing. The second subassembly, consisting of the pawl disc, collar, pawl case, pawl toggle, toggle switch, springs, and all related mounting hardware, is fixed to the 5/8” shaft.

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Figure 5. Two-Way Ratchet exploded view

When the device is set to the freewheel mode (Figure 6a), only one pawl is engaged. This allows the sprocket assembly to rotate freely on the shaft in the clockwise direction (when viewed from the bearing side), independent of the pawl assembly. However, the subassemblies rotate together when the sprocket rotates counter-clockwise, as the pawl engages with the internal gear. This allows the device to function as a typical freewheel sprocket, transferring pedalling power to the drive wheels, but ensures that the rotation of the wheels does not drive the pedals. In the context of the client’s tricycle, this mode would be engaged when the rider needs a rest, but the tricycle is being pushed by the caregiver. When the device is switched to fixed mode (Figure 6b), both pawls are engaged and prevent relative motion between the subassemblies in either direction. The pedals will drive the wheels, and the wheels will also drive the pedals. This mode is used when the caregiver is pushing the tricycle and movement of the rider’s legs is desired.

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Figure 6. Design mechanism - a) freewheel mode b) fixed drive mode

2.1 Sprocket Design

Two interchangeable sets of sprocket designs (Figure 7) are included in the final design to test the effectiveness of two internal tooth profile options in the prototyping phase. Figure 7a has a triangular internal tooth profile. Figure 7b has an internal involute gear tooth profile. Both profiles are outlined by a red circle.

Figure 7. Interchangeable sprocket designs: a) triangle tooth design b) gear tooth design

The geometry of the was constrained by the smallest required sprocket size, a standard ½” pitch 18-tooth sprocket. The internal and external involute curve profiles for one of the sprocket designs was projected from a KHK 100-tooth internal gear [10] and a McMaster- Carr® 18 x ½” sprocket [11], onto a 0.125” laser cut plate (Figure 8). The second sprocket was developed using the same external sprocket profile with a custom internal gear profile with a similar pitch diameter to the internal gear. The internal gear profiles were restricted by the need to have relatively small teeth to reduce , and a pitch diameter that was large enough to maximize the space within the gear profile. The remaining space between the profiles needed to be large enough to accommodate fasteners that will not interfere with the chain.

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Figure 8. Sprocket design projected from standard tooth profiles

The sprocket component can be replaced with the 22 or 26-tooth sprocket profiles requested by the client with no further modifications required to the assembly. These variations share the same mounting holes and internal tooth profiles (Figure 9).

Figure 9. 26, 22, 18-tooth sprocket options

The two internal profiles were considered because backlash, engagement reliability, and wear is difficult to compare or predict without testing. Two sets of 18, 22, and 26-tooth sprockets, two sets of pawls, and two pawl case components are included with the final design. During prototyping phase, the profiles will be tested to

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determine which performs best based on the backlash and ability to reliably lock with the pawls. 2.2 Pawl Design

Like a typical ratchet (Figure 10), the design must transmit torque through relatively small teeth and toggled to function in either direction. Therefore, inspired by a ratchet, the pawls have multiple teeth to share the load when transmitting torque. The pawls have the same tooth profile as the internal gear.

Figure 10. Pawl and gear design in a typical ratchet [12]

The axis of rotation of the pawl was located such that the pressure angle from the internal tooth profile will produce a moment on the pawl, forcing it out of contact with the internal gear when in freewheel mode (Figure 11a). In the locking direction (Figure 11b), the pressure angle will produce a moment in the opposite direction, seating the pawl deeper into the internal gear and locking it in place.

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Figure 11. Design mechanism - a) Freewheel mode b) Direct drive mode

The shape, housing, and spring design for the pawls were inspired by a standard freewheel sprocket (Figure 12).

Figure 12. Standard freewheel pawl design [13]

2.3 Toggle Mechanism

The finalised toggle mechanism (Figure 13) rotates the entire pawl toggle away from the internal gear so the pawl is unable to contact the internal gear even when the spring is fully extended.

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Figure 13. Toggle assembly

The pawl case locks into the two drive modes through friction on the lobe (Figure 14). The lobe interface with the pawl case is designed such that the force required to switch the lobe between the two positions is achievable through intentional actuation, but resistive enough to prevent an inadvertent switch of drive modes during normal operation. The optimal geometry for the lobe is difficult to predict and will require testing and modification in the prototyping phase before it is finalised.

Figure 14. Pawl case securing mechanism

The switch, consisting of a clevis pin and the switch handle, protrudes out the backside of the device and is responsible for the rotation of the pawl case for the two drive modes (Figure 15). The switch clevis is fastened to the rotating pawl case with a spring pin (Figure 14).

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Figure 15. Complete assembly - switch side

2.4 Material Considerations

Properties considered for the component materials include; strength (due to the durability and operation requirements), and corrosion (due to the environment in which the mechanism will be exposed). Stainless-steel hardware will be selected where possible to prevent corrosion. Table III summarizes the stainless-steel grades used for the fabricated components of the design. Stainless-steel is used where possible to avoid potential seizing from corrosion, however, galvanic corrosion may occur due to the use of dissimilar metals. Specifically, the needle bearing, spring pins, locking collar, and mounting hardware are not available in stainless-steel. To counteract galvanic corrosion, inhibitors in the lubrication will be applied between the stainless-steel components and steel components. Inhibitors act by interrupting the chemical reaction from causing corrosion between components [14]. A maximum rider weight of 250 lbs is identified, requiring the mechanism to withstand a maximum load of 250 lbs applied to the pedals on the longest available pedal crank arm of 5”. The complete stress analysis shown in Appendix B uses a safety factor of 1.5. Table III shows the stainless-steel grades specified for the fabricated components of the mechanism. The pawls are specified to be 347 Annealed Stainless Steel (SS) sheets, a softer grade, while the other components are specified to be 202 25% Hardened SS sheet. The pawls are a softer material and are designed to be sacrificial as they are much easier and inexpensive to replace than the sprocket component. This failure mode will automatically default the device to freewheel mode; the worn pawls will be unable to engage the internal profile of the sprocket, and therefore will be unable to transmit power between the rear wheels and the pedals.

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TABLE III. SUITABLE MATERIALS FOR EACH MACHINED PART

Requirement Stainless Steel Part Specification Hardness (F.S. = 1.5) Grade Sprocket 46.2 Ksi Fatigue 202 25% Hard 48.0 Ksi Endurance 300 HB Strength Sheet Limit Pawl 44.7 Ksi Bearing 347 Annealed 47.5 Ksi Endurance 210 HB Strength Sheet Limit Pawl Toggle 44.7 Ksi Bearing 202 25% Hard 48.0 Ksi Endurance 300 HB Strength Sheet Limit Pawl Case 79.484 Ksi Bearing 202 25% Hard 84.0 Ksi Yield 300 HB Strength Sheet Strength Pawl Disc 50.7 Ksi Bearing 202 25% Hard 84.0 Ksi Yield 300 HB Strength Sheet Strength

Alternative pawl materials such as AMPCO M4 or AMPCO 8 will be tested during the prototyping phase and compared to the stainless-steel [15]. These materials offer good wear resistance and require little lubrication, resulting in less required maintenance of the mechanism. However, additional costs, availability, and compatibility with other materials need to be evaluated further.

3.0 Design Summary

3.1 Preliminary Failure Modes and Effects Analysis

A PMFEA was completed to identify and mitigate possible risks in the design (Appendix C). A risk priority number is identified for each risk, and is a function of the risk’s estimated severity, occurrence, and prevention. The top five risks are shown with their risk priority number (Table IV). This analysis was completed with the assumption the design will be manufactured according to specifications. TABLE IV. TOP FIVE RISKS

Potential Failure Mode Design Prevention Risk Priority Number Worn out lobe/ lobe-seat Testing, material selection 168 Spring failure/dislocation Use of commercial pawl springs, testing 126 Mechanism disassembles Seat set screws in shaft during install, testing 120 Sprocket tooth failure Material selection 112 Jamming of moving parts Mechanism is sealed, Stainless-steel components 100

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Several risks require prototype testing as a primary source of design control or prevention. Therefore, a subsequent PFMEA will be completed after prototyping and testing to identify and evaluate remaining risks. 3.2 Maintenance

To access the pawls for replacement, the face mount shaft collar must first be loosened off the shaft to open the assembly. The damaged pawls are now accessible and can replaced with new pawls (Figure 16). This procedure should be accompanied by a thorough cleaning and lubrication of the mechanism to ensure any broken teeth and other debris are completely removed.

Figure 16. Pawl replacement

Lubricating the internal components of the mechanism is essential to reduce the wear on the small teeth of the pawls and resist corrosion. A white lithium grease is recommended for the lubrication of the internal ratchet teeth and pawls. A light coating of lithium grease is optimal for durability and wear resistance during metal-on-metal contact and will not leak out of the assembly. Key benefits to this specific type of grease is that it is long lasting, an extreme friction reducer, and does not melt, run, wash off or freeze. [16]

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3.3 Assembly Procedure

To ensure proper assembly and operation of the mechanism, the intended assembly and installation steps are detailed below. Pawl Disc Assembly: 1) Weld the toggle handle to the clevis pin so that the handle points along the axis of the clevis pin thru hole (Figure 17).

Figure 17. Pawl Disc assembly sequence – Step 1

2) Press the flush mount nuts into the pawl case (Figure 18).

Figure 18. Pawl Disc assembly sequence – Step 2

3) Fasten pawl case to pawl disc using socket head screws to the opposite side of the pawl disc from the collar (Figure 19).

Figure 19. Pawl Disc assembly sequence – Step 3

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4) Mount the 5/8” face mount collar to the pawl disc (Figure 20).

Figure 20. Pawl Disc assembly sequence – Step 4

5) Insert the clevis pin through the spacer into the backside of the pawl disc (where the collar is mounted) through the pawl toggle located on the other side of the pawl disc. Fasten the clevis pin to the pawl toggle using the spring pin (Figure 21).

Figure 21. Pawl Disc assembly sequence – Step 5

6) Slide the springs and pawls into their respective housings on the pawl case and pawl toggle, in the orientation shown (Figure 22).

Figure 22. Pawl Disc assembly sequence – Step 6

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Sprocket Assembly: 1) Weld sprocket hub plate to sprocket hub flange, do not weld on the interior of the sprocket hub flange. Groove for retaining ring should be opposite of flange (Figure 23).

Figure 23. Sprocket assembly sequence – Step 1

2) Press the ball bearing into the sprocket hub (Figure 24).

Figure 24. Sprocket assembly sequence – Step 2

3) Install internal retaining ring into sprocket hub (Figure 25).

Figure 25. Sprocket assembly sequence – Step 3

4) Fasten the sprocket, sprocket hub, and sprocket spacer together using three spring pins (Figure 26).

Figure 26. Sprocket assembly sequence – Step 4

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Installation Procedure: 1) Slide the sprocket assembly, set screw collar, and the pawl assembly, onto shaft and align the sprocket with the location of the chain. Ensure all three components are in contact (Figure 27).

Figure 27. Installation sequence – Step 1

2) Tighten both collars onto the shaft (Figure 28).

Figure 28. Installation sequence – Step 2

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3.4 Cost Summary

The costs of custom parts are estimated by the client [17]. Standard part prices are obtained from McMaster-Carr® in USD [11], and were converted using the current exchange rate of $1.32 on November 19, 2018. The total cost of parts for the prototype is estimated to be $133.99 (Table V) and is based on manufacturing an 18-tooth sprocket with triangle internal teeth. The price does not include the labour required to assemble the device. A detailed bill of materials is provided in Appendix D. TABLE V. COST SUMMARY

Unit Cost Ext. Cost Part QTY (CAD) (CAD) Pawl Toggle 2.98 1 2.98 Sprocket Plate 13.65 1 13.65 18T Sprocket w/ Triangle Teeth 20.58 1 20.58 Spacer - Triangle 15.70 1 15.70 Pawl - Triangle 1.56 2 3.12 Pawl Case - Triangle 8.44 1 8.44 Pawl Spring 0.98 2 1.96 Pawl Disc 14.10 1 14.10 Toggle Handle 1.43 1 1.43 Hardware 52.03 N/A 52.03 Total 133.99

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4.0 Conclusion

The University of Manitoba worked alongside Freedom Concepts Inc. to develop an intuitive, reliable and tool-free drive mode mechanism for adaptive tricycles. The Two-Way Ratchet design allows the caregiver to toggle between freewheel and direct drive modes with the simple actuation of a toggle switch. The design consists almost entirely of laser cut and off-the-shelf components to reduce low volume production costs and allow design changes in the prototyping phase, without high tooling expenses and redesign time. The cost of the prototype design is approximately $133.99 CAD. The longevity of the design is supported by full stainless-steel construction, sealed bearings and sacrificial replacement parts to allow for easy maintenance. Included with the design is a bill of materials, cost breakdown, preliminary failure modes and effects analysis, assembly instructions, and preliminary engineering drawings of each manufactured component. Sprocket profiles for the 18, 22, and 26-tooth variations are also included. Two sprocket variations will be tested and finalised in the prototyping phase. The Two-Way Ratchet design meets the needs set out by the client for an intuitive, reliable, low cost and tool free design that is fully compatible with all of Freedom Concepts’ current sprocket configurations. The ease of use ensures the device will be used as intended and ordered more frequently to improve sales and satisfaction of Freedom Concepts’ customers.

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5.0 References

[1] G. D. Hiscox, Mechanical Movements and Devices, Algrove Publishing, 1999.

[2] N. P. Chironis and N. Sclater, Mechanisms and Mechanical Devices Sourcebook, New York, NY: McGraw-Hill, 1996.

[3] N. R. Engel, "Freewheel Assembly Switchable Between Fixed-Gear and Freewheel Modes". United States of America Patent 2017/00986030 A1, 6 Oct. 2016.

[4] J. M. Allen, "Bicycle Freewheel". United States of America Patent 3,972,245, 20 Aug. 1974.

[5] Bitex, "FreeHub Body (MTB)," Bitex, 2018. [Online]. Available: http://bitexhubs.com/htm/company.php. [Accessed 31 October 2018].

[6] Kun Teng Industry Co., Ltd., "Tawan KT," 2018. [Online]. Available: http://www.kttw- hub.com/pro.php?f=6&cid=6. [Accessed 1 November 2018].

[7] Wheel Giant Inc., Taiwan Bicycle Source, Changhua City: Grace S. Ruan, 2015.

[8] C. Bock, "Private Communication," Freedom Concepts Inc., 2018.

[9] Lambert, "Hubs," 2018. [Online]. Available: www.hlc.bike/ca/. [Accessed 10 November 2018].

[10] Kohara Gear Industry Co.,Ltd, "KHK Stock - S10.5-100," 2015. [Online]. Available: https://khkgears2.net/catalog7/SI0.5-100. [Accessed 12 November 2018].

[11] McMaster-Carr, 2018. [Online]. Available: https://www.mcmaster.com/. [Accessed 17 November 2018].

[12] "Ratchet Internals - | Tools | Pinterest | Engineering, Tools and Mechanical design," Pinterest, 2015. [Online]. Available: https://www.pinterest.ca/pin/564287028290399915/?lp=true. [Accessed 18 November 2018].

[13] "Stack Exchange," [Online]. Available: https://bicycles.stackexchange.com/questions/44990/what-freewheel-mechanism- designs-are-used-in-bicycles. [Accessed 19 November 2018].

[14] W. D. Callister and D. G. Rethwisch, Materials Science and Engineering: An Introduction, New Jersey: Wiley, 2014.

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[15] AMPCO METAL, "Product Selection Guide," AMPCO METAL, 2018. [Online]. Available: https://www.ampcometal.com/product-selection-guide/. [Accessed 2 Decemeber 2018].

[16] JIG-A-LOO, "White Lithium The Ultimate Heavy Duty Lubricant," [Online]. Available: http://www.jigaloo.ca/lubricant/2-white-lithium.html. [Accessed 02 12 2018].

[17] C. Bock, Interviewee, Private Communication. [Interview]. 3 December 2018.

[18] Bearings Canada, "6802-2RS Sealed Bearing 15x24x5 Ball Bearings," [Online]. Available: https://www.bearingscanada.com/6802-2RS-Sealed-Bearing-15x24x5-Ball-Bearings- p/6802-2rs-sealed-15x24x5-ball.htm. [Accessed 31 October 2018].

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A Appendix A – Concept Development

Table of Contents A.1 Concept Requirements ...... A-2 A.2 Concept Generation ...... A-3 A.3 Development of the Top Four Concepts ...... A-5 A.3.1 Teeth Engagement ...... A-5 A.3.2 Two-Way Ratchet ...... A-6 A.3.3 Toggle Latch ...... A-7 A.3.4 Flanged Freewheel ...... A-8 A.4 References ...... A-10

List of Figures Figure A-1. House of Quality ...... A-2 Figure A-2. Concept description and features example ...... A-3 Figure A-3. Exploded view of the Teeth Engagement concept ...... A-5 Figure A-4. Assembled view of the Teeth Engagement concept ...... A-5 Figure A-5. Exploded view of the Two-Way Ratchet concept ...... A-6 Figure A-6. Assembled view of the Two-Way Ratchet concept ...... A-7 Figure A-7. Exploded view of the Toggle Latch concept ...... A-7 Figure A-8. Assembled view of the Toggle Latch concept ...... A-8 Figure A-9. Exploded view of the Flanged Freewheel concept ...... A-8 Figure A-10. Assembled view of the Flanged Freewheel concept ...... A-9

List of Tables TABLE A-I. RESULTS OF FUNCTION-BASED BRAINSTORMING ...... A-3 TABLE A-II. HIT MATRIX ...... A-4 Table A-III. RESULTS OF TOP 4 CONCEPTS ...... A-4

A-1

A.1 Concept Requirements A House of Quality (Figure A-1) analyzed the drive mode mechanism project, with the identified client needs along the vertical and the metrics along the horizontal. The triangular area above the metrics shows positive and negative correlations between the metrics. The centre of the House of Quality depicts the relationship between the client needs and metrics. These relationships are categorized as strong, moderate, and weak. The bottom area of the House of Quality shows the relative weight of each of the metrics. This relative weight for each metric is a function of importance of the related needs, the strength of the relationships between needs and metrics, and quantity of needs related to each metric.

Figure A-1. House of Quality [1]

A-2

The House of Quality established that “Actuate Without Use of Tools” is the metric with the highest relative weight at 28%. “Time Required to Actuate” and “Withstands Maximum Torque from Chain” have the second highest relative weight at 15% each. A.2 Concept Generation Methods to achieve each primary function are listed in Table A-I. TABLE A-I. RESULTS OF FUNCTION-BASED BRAINSTORMING

a) b) c) Unidirectional Locking Actuation Rotation 1 Freewheel 1 Pawl 1 Brake cable 2 Differential 2 Friction 2 Thumbscrew/ wingnut 3 Ratchet 3 Automotive clutch 3 Squeezing 4 Freehub 4 Magnet 4 Push button toggle (pen) 5 One-way Bearing 5 Pin engagement 5 Overextend to release (seatbelt) 6 Adhesive 6 Electronic switch 7 Velcro 7 Spring loaded 8 Electromagnets 8 Camlock 9 Car door release 9 Turn on threads 10 Door latch 10 Toggle Latch

Proceeding the concept generation phase, each concept was gathered into a table as seen in Figure A-2. Each table provides a high-level overview of each concept.

Figure A-2. Concept description and features example

A-3

The criteria used to evaluate each concept were derived directly from the customer needs. A HIT matrix (Table A-II) was used to decide the weight of each criteria. TABLE A-II. HIT MATRIX

CRITERIA A B C D E F A Design Simplicity A A A A A A B Engagement Reliability --- B B B B B C Potential Hazards ------C C E C D Engagement Effort (User) ------D D D E Elegance ------E E F Assembly time ------F Hits 6 5 3 3 3 1 Weight 0.286 0.238 0.143 0.143 0.143 0.048

While one of the needs identified by the client was “inexpensive”, a detailed cost breakdown was considered premature during this phase.

The results of the top four concepts are included in Table A-III. Table A-III. RESULTS OF TOP 4 CONCEPTS

Concept Names: Two-Way Ratchet Teeth Engagement Weighted Weighted Weight Selection Criteria Rating Rating Score Score 0.286 Design Simplicity 4 1.144 4 1.144 0.238 Engagement Reliability 5 1.190 5 1.190 0.143 Low Potential Hazards 5 0.715 4 0.572 0.143 Low Engagement Effort 5 0.715 3 0.429 0.143 Elegance 5 0.715 4 0.572 0.048 Low Assembly time 4 0.192 4 0.192 Score out of 10 9.342 8.198

Concept Names: Flanged Freewheel Toggle Latch Weighted Weighted Weight Selection Criteria Rating Rating Score Score 0.286 Design Simplicity 4 1.144 4 1.144 0.238 Engagement Reliability 5 1.190 4 0.952 0.143 Low Potential Hazards 5 0.715 4 0.572 0.143 Low Engagement Effort 4 0.572 3 0.429 0.143 Elegance 4 0.572 3 0.429 0.048 Low Assembly time 3 0.144 4 0.192 Score out of 10 8.674 7.436

A-4

A.3 Development of the Top Four Concepts The following four concepts were presented to Freedom Concepts. After having met with the client to discuss each concept, the two parties agreed to pursue two final designs into Phase III of the project. A.3.1 Teeth Engagement The design, Figure A-3, uses a twist grip to guide the sprocket control along the shaft hub, engaging the sprocket flywheel. Once engaged the sprocket is in direct drive mode. The sprocket control rotates with the shaft and is kept in place by keyways along the shaft hub. The sprocket flywheel is connected to the freewheel sprocket via fasteners – this can be accomplished by sourcing a freewheel sprocket with holes – while the sprocket is threaded onto the sprocket hub. The sprocket hub and shaft hub are fixed to the shaft via set screws.

Figure A-3. Exploded view of the Teeth Engagement concept

Figure A-4. Assembled view of the Teeth Engagement concept

Design considerations include; adding a rubber cover or knurl to the twist grip to aid in the twisting motion, the addition of a spring between the sprocket control and flywheel to prevent accidental engagement, as well as placing a locknut or a positive locking device at the end of the twist grip.

A-5

The design is easily adaptable for all pedal power options, and the twist grip can be activated by placing the foot on the grip and pushing the tricycle. A drawback to the concept is the freewheel sprocket sourcing – if a sprocket manufactured with holes is not readily available, holes would need to be added, which would require a sprocket with greater clearance between the teeth and freewheel component.

A.3.2 Two-Way Ratchet The Two-Way Ratchet (Figure A-5) consists of two separate disc assemblies; the pawl disc which is securely fixed to the shaft with a collar, and the sprocket disc that interfaces with the shaft through a ball bearing, allowing to rotate independently of the shaft. The two discs can only be engaged by the pawls attached to the fixed plate, which can engage the free disc in either direction.

Figure A-5. Exploded view of the Two-Way Ratchet concept

When both pawls are engaged, the sprocket disc assembly locks to the pawl disc, forcing the entire mechanism to rotate as one unit with the shaft. With only one pawl engaged, the sprocket disc is only fixed in one direction, but free to rotate in the other. The engagement of the pawl is controlled by a spring and a thumb screw protruding through the other side of the pawl disc.

To support a ratcheting actuation in both directions, the shape of the internal profile and pawls is adopted from a common reversible handheld ratchet. These profiles will be able to support the required torque while rotating freely in both directions. An assembled view is shown in Figure A-6.

A-6

Figure A-6. Assembled view of the Two-Way Ratchet concept

A potential obstacle of the Two-Way Ratchet is the mechanism that controls the lateral position of the fixed and free disc assemblies. The fixed and free disc need to be close enough so that the pawls can reliably engage the inner sprocket but far enough away that the two assemblies do not rub against each other. To eliminate this, the addition of spacers was considered.

A.3.3 Toggle Latch The toggle latch design (Figure A-7) incorporates a toggle latch to engage the drive mode of the tricycle. There are three main parts for the design; the extended hub, the over hub, and the toggle latch. The design disables the freewheeling motion by physically connecting the over hub to the outer race of the sprocket by friction. The over hub slides along the extended hub as a guide towards the freewheel sprocket. The movement of the over hub is due to a toggle latch, also known as a draw latch, which draws the two items together by tension.

Figure A-7. Exploded view of the Toggle Latch concept

A-7

An assembled view is shown in Figure A-8.

Figure A-8. Assembled view of the Toggle Latch concept

Benefits of the design include compatibility with current parts such as the hub and freewheel sprocket, and compatibility with all gear types. Considerations are; sourcing a toggle latch with a smaller foot print, having a spline serve as the connection between the extended hub and the over hub, adding a grommet between the sprocket and over hub to reduce friction, implementing a latching system which will not protrude from the shaft when disengaged. A.3.4 Flanged Freewheel A slight variant on the Teeth Engagement concept, the Flanged Freewheel design replaces the freewheel sprocket with a flanged freewheel. The flanged freewheel comes with holes for attaching components and eliminates drilling holes in the sprocket freewheel. An exploded view of the concept can be seen in Figure A-9, while the assembled concept is shown in Figure A-10.

Figure A-9. Exploded view of the Flanged Freewheel concept

A-8

Figure A-10. Assembled view of the Flanged Freewheel concept

Further development of this concept may include the use of a spring to prevent the grip from freely sliding axially along the shaft resulting in accidental. Additionally, multiple parts such as the threaded hub and flanged freewheel may be replaced by a variant of standard bike component – the freehub. A hub with internal teeth to engage with the freehub pawls would be added and fixed to the shaft. This variation could result in a smaller mechanism compared to the flanged freewheel.

A-9

A.4 References

[1] C. Battles, "Free QFD Templates," QFD Online, 23 April 2010. [Online]. Available: http://www.qfdonline.com/templates/. [Accessed 20 September 2018].

A-10

B Appendix B – Stress Analysis

Table of Contents

B.1 Analysis ...... B-2 B.1.1 Front Sprocket ...... B-2 B.1.2 Rear Sprocket Tooth ...... B-3 B.1.3 Sprocket ...... B-4 B.1.4 Pawl ...... B-5 B.1.5 Pawl Case ...... B-6 B.1.6 Pawl Disc ...... B-7 B.2 References ...... B-9

List of Figures Figure B-1. Front Sprocket free body diagram ...... B-2 Figure B-2. Free body diagram of sprocket tooth ...... B-3 Figure B-3. Sprocket free body diagram ...... B-4 Figure B-4. Pawl free body diagram ...... B-5 Figure B-5. Pawl case free body diagram ...... B-6 Figure B-6. Pawl disc free body diagram ...... B-7

List of Tables TABLE B-I. COMPONENT MATERIALS AND REQUIREMENTS...... B-8

B-1

B.1 Analysis From the client’s specifications, the maximum allowable weight of a rider for the tricycle must be 250 lbs. Assuming a rider can only apply their full weight on the pedals, an allowable load of 250 lbf will be applied to the pedals. Applying a safety factor of 1.5 shows a maximum load of 375 lbf. The following calculations identify the maximum tensile load applied by a chain with a chain pitch of 0.5 in. B.1.1 Front Sprocket Free Body Diagram T F = 375 lbf

D_D

A

L_D

Figure B-1. Front Sprocket free body diagram

Force Calculations The front sprocket can be configured for either 32 tooth or 26 tooth and have a crank arm length of 3 in, 4 in, or 5 in.

The diametral pitch for the 32 tooth and 26 tooth configuration can be found from the following equation: � � = � 180 sin ( � ) Where � = 0.5 ��, � = 26 or 32

Applying a net momentum equation about A using Figure B-1 produces the equation for T:

∑ �� = 0 = �(��) − �(��)

�(��) � = �� Where

�� = 3 ��, 4 ��, �� 5 ��,

�� � = � 2 B-2

A maximum tensile load of 905.92 lbf was found to be applied by a 26 tooth front sprocket with a 5 in crank arm length.

� = 905.92 ��� B.1.2 Rear Sprocket Tooth Only one tooth is considered in the identification of the stress on the sprocket teeth as only one tooth will experience the maximum load. The other teeth will only experience a fraction of the maximum applied load. To identify the cyclic stress being applied by the chain to the tooth, the bearing stress applied by the chain roller onto a static sprocket was used.

Free Body Diagram T = 905.92

lbf

Figure B-2. Free body diagram of sprocket tooth

Stress Calculation 1 �������� �ℎ�������, �� = ⁄8 �� 5 ������ �ℎ��� ������, �� = ⁄32 �� � ��,� = �� ∙ ��

��,� = 46.4 ���

The bearing stress on the tooth, ��,�, is the stress between the contact of the roller and the sprocket tooth. Figure B-2 show the contact area between the chain and the sprocket is the radius of the roller chain and the thickness of the sprocket.

Since the rear sprocket tooth is experiencing a cyclic load of 46.4 Ksi, a material with an endurance limit greater than 46.4 Ksi is required. 202 Grade 25% Hard Stainless Steel (SS) matches this requirement with an estimated endurance limit of 50.0 Ksi. 202 Grade 25% Hard SS has a listed ultimate tensile strength of 100.0 Ksi [1].

Endurance limit of steel alloys can be estimated with the following equation [2]:

0.5 ��� ��� ≤ 200 ���� (1400 ���) ′ �� = {100 ���� ��� > ���� 700 ��� ��� > 1400 ���

B-3

B.1.3 Sprocket The sprocket will undergo force calculations to identify the transmitted load onto the pawls. The sprocket can have 18, 22, and 26 teeth.

Free Body Diagram

T = 350 lbf

rS

A

ri

Fp

Figure B-3. Sprocket free body diagram

Force Calculations The sprocket size varies with the number of teeth. The diametral pitch of the sprocket can be found from the following equation [3]: � ��������� ����ℎ, � = �� � 180 sin ( � ) Where � = 0.5 ��, � = 18, 22, or 26

�� �������� ������ ����ℎ, � = , � 2

�������� �������� ������, �� = 0.999 ��

Applying a net momentum about A equation from Figure B-3 produces the equation to identify FP

∑ �� = 0 = �(��) − ��(��)

�(��) �� = = 1881.52 ��� �� The maximum load applied to the pawl is 1881.52 lbf on a 26 tooth sprocket.

B-4

B.1.4 Pawl The pawl is designed to be the sacrificial part of the design to ensure the safe failure mode of the mechanism. The pawl must be a softer material compared to the sprocket to ensure the pawl will fail first compared to the other components of the mechanism.

Free Body Diagram

Fp

lp

dp

Fp

Figure B-4. Pawl free body diagram

Stress Calculation To simplify the calculations for stresses on the pawl, the smallest cross sectional area of the pawl was identified to endure the most stress. The cylinder face and the shaft, highlighted yellow in Figure B-4 is the cross section analyzed.

The length of the highlighted section was found from the CAD model.

���� �����ℎ, �� = 0.168 ��

���� �ℎ�������, �� = 0.25 ��

�� � = �� ∙ �� � = 44.80 ��� The pawl experiences a maximum 44.80 ksi instantaneous stress once the tricycle starts moving. A cyclic stress of 44.80 ksi is then experienced by the pawl over the course of its life time. A material with an endurance limit greater than 44.80 ksi is required to ensure component durability. 347 Annealed SS has an estimated endurance limit of 47.5 Ksi and a Brinell Hardness of 163 HB (approximately 4 HRC). 202 25% Hard SS has a listed hardness of 300 HB (approximately 33 HRC), significantly greater than 347 Annealed SS [1] [4].

B-5

B.1.5 Pawl Case The pawl case will undergo force calculations as well as stress calculations due to the bearing stress between the pawl and the pawl case, and the pawl case and the fasteners.

Free Body Diagram

Fp

Fb1 rp Fb1 rh1

rh1

A rh1

Fb1

Figure B-5. Pawl case free body diagram

Force Calculations ����� �� ����, �� = 1881.52 ���

���� ���� �ℎ�������, �� = 0.2 ��

������ �� ���� ����, �� = 0.87 ���

������ �� 3/16 ���������, �ℎ1 = 0.77 �� Applying a net momentum equation about A in Figure B-5 provides the equation to calculate the force on a single fastener, Fh1.

∑ �� = 0 = 3��1(�ℎ1) − ��(��)

��(��) ��1 = = 606.57 ��� 3(�ℎ1) Stress Calculation Bearing Stress from Pawl ����� �� ����, �� = 1881.52 ���

���� ���� �ℎ�������, �� = 0.2 ��

B-6

�������� �� �������� ���� �� ����, �� = 0.12 ��

�� ��,� = = 79.65 ��� �� ∙ ��� Bearing Stress from Fasteners �������� �� �ℎ��� ���������, �3� = 0.12 ��

��1 �3�,� = = 23.33 ��� �3� ∙ ��� The maximum stress experienced by the pawl case is from the pawl itself. A material with a yield strength greater than 79.65 ksi is required for the pawl case not to deform. 202 25% Hard SS has a listed yield strength of 84 ksi, and so specified for the pawl case. B.1.6 Pawl Disc The Pawl Disc is the final component that transfers torque from the pawls to the axle and as such would require force analysis to identify stresses applied to the contact between fasteners and plates.

Free Body Diagram

Fb1

rh1 Fb2

rh1 Fb1 rh2 Fb1 rh2 A rh1

Fb2

Figure B-6. Pawl disc free body diagram

B-7

Force Calculations ����� �� ��� �� �ℎ� �ℎ��� 1/8 ���������, ��1 = 1881.52 ���

������ �� 3/16 �� ��������� , �ℎ1 = 0.77 ��

������ �� 5/16 �� ��������� , �ℎ1 = 0.48 �� Applying a net momentum equation about A in Figure B-6 provides the equation to calculate the force on a single fastener, Fb2

∑ �� = 0 = 3��1(�ℎ1) − 2��2(�ℎ2)

3��1(�ℎ1) ��2 = = 1459.72 ��� 2(�ℎ2) Bearing Stress from Fasteners �ℎ������� �� ���� ����, ��� = 0.125 �� 3 x 3/16 in fasteners

��1 �3�,� = = 37.33 ��� �3� ∙ ��� 2 x 5/16 in fasteners

��2 �2�,� = = 50.79 ��� �2� ∙ ��� From the bearing stress calculations, a maximum stress of 50.79 ksi is experienced by the pawl disc. A material with a yield strength greater than 50.79 ksi is required for the pawl disc not to fail under load. 202 Grade 25% Hard SS has a yield strength of 84 ksi, which can be used for the pawl disc. Table B-I lists all component materials and requirements. TABLE B-I. COMPONENT MATERIALS AND REQUIREMENTS

Requirement Stainless Steel Part Specification Hardness (F.S. = 1.5) Grade Sprocket 46.2 Ksi Cyclic Stress 202 25% Hard 70.0 Ksi Endurance 33 HRC Sheet Limit Pawl 44.7 Ksi Cyclic 347 Annealed 47.5 Ksi Endurance 4 HRC Bearing Stress Sheet Limit Pawl Toggle 44.7 Ksi Cyclic 202 25% Hard 70.0 Ksi Endurance 33 HRC Bearing Stress Sheet Limit Pawl Case 79.484 Ksi Bearing 202 25% Hard 84.0 Ksi Yield Strength 33 HRC Stress Sheet Pawl Disc 50.7 Ksi Bearing 202 25% Hard 84.0 Ksi Yield Strength 33 HRC Stress Sheet

B-8

B.2 References

[1] Iron Boar Labs Ltd., "Quarter-Hard 202 Stainelss Steel," Iron Boar Labs Ltd., 2018. [Online]. Available: https://www.makeitfrom.com/material-properties/Quarter-Hard-202-Stainless-Steel. [Accessed 30 November 2018].

[2] R. G. Budynas and J. K. Nisbett, "Chapter 6-7: The Endurance Limit," in Mechanical Engineering Design, 10th Ed., New York, McGraw-Hill Education, 2015, pp. 290 - 291.

[3] R. L. Mott, "Chapter 7-6 Chain Drives," in Elements in Mechanical Design, 5th Ed., Pearson, 2014, p. 259.

[4] J. R. Davis, Metals Handbook. Desk Ed., 2nd ed, ASM International, 1998.

B-9

C Appendix C – Preliminary Failure Modes and Effects Analysis

Table of Contents C.1 Analysis ...... C-2 C.2 References ...... C-6

List of Figures Figure C-1. Criticality chart ...... C-5

List of Tables TABLE C-I. PFMEA RISK PRIORITY ASSESSMENT ...... C-2 TABLE C-II. SEVERITY RANKING SCALE ...... C-3 TABLE C-III. PROBABILITY RANKING SCALE ...... C-4 TABLE C-IV. PREVENTATION RANKING SCALE ...... C-4 TABLE C-V. PFMEA CRITICALITY ASSESSMENT ...... C-5

C-1

C.1 Analysis 11 potential failure modes are identified for the drive mode mechanism (Table C-I). Each failure mode is given a ranking of severity (S) (Table C-II), occurrence (O) (Table C-III) and prevention (C) (Table C-IV). A risk priority number (RPN) is the product of the severity, occurrence and prevention rankings, and is calculated for each potential failure mode.

The severity, occurrence and prevention rankings are estimated values by the design team, and several potential failure modes will require prototype testing to more accurately predict. These estimations are made under the assumption the design will be manufactured according to specifications. TABLE C-I. PFMEA RISK PRIORITY ASSESSMENT

Risk Function Potential Potential S Potential O Current Design P RPN ID Failure Effect(s) of Cause(s) of Prevention Mode Failure Failure 1 Freewheel Pawl fails Does not 5 Material fatigue, 4 Testing, material 4 80 or Direct transmit torque wear, selection Drive deformation 2 Mode Internal Does not 6 Material fatigue, 4 Testing, material 4 96 tooth fails transmit torque wear, selection deformation 3 Shaft collar Does not 6 Loosening of set 4 Loctite set 3 72 slips on axle transmit torque screw screw, counter sink shaft during installation 4 Sprocket Chain failure 7 Fatigue, material 4 Material 4 112 tooth fails wear selection 5 Spring Does not 6 Material fatigue, 3 Selection of 7 126 failure transmit torque deformation, commercial dislocation pawl springs, Testing 6 Jamming of Loss of torque 6 Contamination of 4 Mechanism is 4 96 mechanism internal sealed to and/or mechanisms, prevent freewheel drive, insufficient contamination further damage lubrication to components 7 Mechanism Loss of torque 6 Shearing of 5 Seat set screws 4 120 falls apart transmission spring pins, in shaft by pre- and/or fasteners, drilling shaft freewheel drive, ineffective axial during install further damage constraints (e.g. to components set screws) 8 Freewheel Bearing fails Damage to 6 Contamination of 4 Use of sealed 4 96 Mode shaft, resistance bearing bearings during freewheel

C-2

Risk Function Potential Potential S Potential O Current Design P RPN ID Failure Effect(s) of Cause(s) of Prevention Mode Failure Failure 9 Actuation Jamming of Actuation does 4 Corrosion of 5 Components 5 100 moving not occur with components made of parts input Stainless Steel 10 Worn out Unintentional 7 Material fatigue, 4 Testing, material 6 168 lobe/ lobe- actuation from Deformation selection seat freewheel to direct drive 11 Accidental Unintentional 5 Large centrifugal 2 Testing and 4 40 actuation actuation force, actuation design of toggle catches lobe/lobe-seat, object low profile actuation toggle

TABLE C-II. SEVERITY RANKING SCALE [1]

Severity of Effect Ranking Unreasonable to expect that the minor nature of this failure would cause any Minor substantial effect on system performance or on a subsequent process or 1 service operation. Customer unlikely to either notice or care about the failure Low severity ranking due to nature of failure causing only a slight customer annoyance. Customer will probably notice only a minor degradation of the Low 2 service performance, or a slight impact on a subsequent action; i.e., some quick, minor rework. Failure causes some customer dissatisfaction. Customer is made uncomfortable or is annoyed by the failure. Customer will experience some Moderate 4, 5, 6 very noticeable inconvenience or performance degradation. May cause either delay due to rework or irreversible damage. High degree of customer dissatisfaction due to the negative impact of the failure such as an inaccurate payroll run, loss of vital data or an inoperable convenience system (i.e., computer crashes). Does not involve safety or High 7, 8 noncompliance to government regulations. May cause serious disruption to subsequent processing; may require major rework or loss to customer and/or create significant financial hardship. Failure mode involves serious personal safety hazards, potential for civil Very High 9, 10 litigation or noncompliance with government regulations

C-3

TABLE C-III. PROBABILITY RANKING SCALE [1]

Probability of Failure Ranking Possible Failure Rates Failure is unlikely. No failures ever associated with Remote 1 < 1 in 20,000 almost identical processes. Process is in Statistical Control. Only isolated failures Very Low 2 1 in 20,000 associated with almost identical processes. Process is in Statistical Control. Isolated failures Low 3 1 in 40,000 associated with similar processes. Generally associated with processes similar to previous 4 1 in 1,000 processes which have experience occasional failures, Moderate 5 1 in 400 but not in major proportions. Process is in Statistical 6 1 in 80 Control. Generally associated with processes that have often 7 1 in 40 High failed. Process is not in Statistical Control. 8 1 in 20 9 1 in 8 Very High Failure is almost inevitable 10 1 in 2

TABLE C-IV. PREVENTATION RANKING SCALE [1]

Likelihood of Detection Ranking Current controls will almost certainly prevent the failure (process Very High 1, 2 automatically prevents most failures) High Current controls have a good chance of preventing the failure 3, 4

Moderate Current controls may prevent the failure. 5, 6

Low Current controls have a poor chance of preventing the failure 7, 8

Very Low Current controls probably will not prevent the failure 9 Absolute Certainty Current controls will not or cannot prevent the failure 10 of Non-Detection

C-4

A criticality rating (CRIT) is determined for each potential failure mode (Table C-V) using the criticality chart (Figure C-1) based on the severity and occurrence, but not prevention. TABLE C-V. PFMEA CRITICALITY ASSESSMENT

Risk ID Function Potential Failure Mode CRIT 1 Freewheel or Pawl fails High 2 Direct Drive Internal tooth fails High Mode 3 Shaft collar slips on axle High 4 Sprocket tooth fails High 5 Spring failure Med 6 Jamming of mechanism High 7 Mechanism falls apart High 8 Freewheel Mode Bearing fails High 9 Actuation Jamming of moving parts Med 10 Worn out lobe / lobe-seat High 11 Accidental actuation Med

The risk IDs are plotted as a function of severity and occurrence to determine their criticality rating (Figure C-1).

Figure C-1. Criticality chart [2]

C-5

C.2 References

[1] Ford Motor Company, FMEA Handbook, Dearborn, MI: Ford Motor Company, 1988.

[2] V. Campbell, "Risk Assessment and Mitigation: Failure Modes and Effects Analysis (FMEA) Presentation," University of Manitoba, Faculty of Engineering, Winnipeg, 2016.

C-6

D Appendix D – Bill of Materials The costs of custom parts are obtained from a quote provided by Russel Metals. Standard part prices are obtained from McMaster-Carr® in USD [1], and converted using an exchange rate of $1.32 on November 19, 2018. The total cost of parts per unit is estimated to be $139.99 (Table D-I) and is based on manufacturing an 18-tooth sprocket with triangle internal teeth. Cost does not include labour required to assemble the device. TABLE D-I. BILL OF MATERIALS Unit Ext. Part Number Part Name Cost QTY Cost (CAD) (CAD) T11-110 Pawl Toggle 2.98 1 2.98 90692A084 1/16"X7/16" Slotted Spring Pin 0.03 1 0.03 9677T23 5/8" Face Mount Shaft Collar 15.84 1 15.84 92330A340 18-8, 1/4"OD x 1/8" Spacer For #6 Screw 1.36 1 1.36 92390A070 18-8,1/8" x 5/16" Clevis Pin 3.66 1 3.66 T11-115 Toggle Handle 1.43 1 1.43 6462K18 5/8" Shaft Collar w/ Set Screw 7.66 1 7.66 99142A520 Internal Retaining Ring, 1-3/8” OD 9.08 1 9.08 60355K705 Ball-bearing - R10-2RS, 5/8” shaft 12.41 1 12.41 T11-120 Sprocket Plate 13.65 1 13.65 90692A142 3/32 x 7/16" Slotted Spring Pin 0.04 3 0.12 T11-125A 18T Sprocket w/ Triangle Teeth 20.58 1 20.58 92220A164 10-24 x 5/8" Socket Head cap screw 0.20 2 0.40 94674A490 4-40 Flush-Mount Press Fit Nuts, 0.062" 0.38 3 1.14 T11-130 Spacer - Triangle 15.20 1 15.20 T11-145 Pawl - Triangle 1.56 2 3.12 T11-135 Pawl Case - Triangle 8.44 1 8.44 T11-140 Pawl Spring 0.98 2 1.96 T11-150 Pawl Disc 14.10 1 14.10 91251A108 4-40 x 3/8" Socket Head Cap Screw 0.11 3 0.33 TOTAL 133.99

References

[1] McMaster-Carr, 2018. [Online]. Available: https://www.mcmaster.com/. [Accessed 17 November 2018].

D-1

Appendix E – Preliminary Engineering Drawings

As the drawings are preliminary, they present the over-all dimensions of each part. Detailed features such as the internal teeth profile, hole size and location, etc., may change during prototyping, and have been excluded. Other notes that should be considered:

- The preliminary drawings consist of two sets based on the internal teeth profile – triangle and gear shaped. The triangle assembly is referred to as T11-100, and the gear teeth assembly as T11-200. - Each drawing presents three sprocket sizes – 18 teeth, 22 teeth and 26 teeth. - Part colours do not represent the final colour and are used for identification purposes only. - The presented drawings exclude those for standard parts such as the shaft collars, machine screws, etc..

E-1

4 3 2 1

ITEM PART NUMBER DESCRIPTION QTY. 7 8 9 10 11 12 14 NO. 1 T11-110 PAWL TOGGLE 1 5/8" FACE MOUNT 2 9677T23 SHAFT COLLAR 1 18-8,1/4"OD X 1/8" 3 92320A340 SPACER FOR #6 1 SCREW 18-8, 1/8 X 5/16" 4 92390A070 CLEVIS PIN 1 1/16 X 7/16" SLOTTED 5 90692A084 SPRING PIN 1 B 6 T11-115 TOGGLE HANDLE 1 B 5/8" SHAFT COLLAR 7 6462K18 W/ SET SCREW 1 1 INTERNAL RETAINING 8 99142A520 RING, 1-3/8" ID 1 9 60355K705 BALL BEARING - R10- 1 2 2RS, 5/8" SHAFT 3/32 X 7/16" SLOTTED 10 90692A142 SPRING PIN 3 3 11 T11-120 SPROCKET PLATE 1 18T SPROCKET W/ 4 12 T11-125A TRIANGLE TEETH 1 13 T11-125B 22T SPROCKET W/ 1 TRIANGLE TEETH 5 14 T11-125C 26T SPROCKET W/ 1 TRIANGLE TEETH 6 10-24 X 5/8" SOCKET 15 92220A164 HEAD CAP SCREW 2 4-40 FLUSH-MOUNT 16 94674A490 PRESS FIT NUTS, 0.062" 3 17 T11-130 SPACER - TRIANGLE 1 PAWL CASE - 18 T11-135 TRIANGLE 1 19 T11-140 PAWL SPRING 2 20 T11-145 PAWL - TRIANGLE 2 21 T11-150 PAWL DISC 1 4-40 X 3/8" SOCKET A 22 91251A108 HEAD CAP SCREW 3 A UNLESS OTHERWISE SPECIFIED: NAME DATE

DIMENSIONS ARE IN MILLIMETERS DRAWN TOLERANCES: FRACTIONAL CHECKED TITLE: ANGULAR: MACH BEND ENG APPR. TWO PLACE DECIMAL TWO-WAY RATCHET 13 17 16 15 18 19 20 21 22 THREE PLACE DECIMAL MFG APPR. INTERPRET GEOMETRIC Q.A. (TRIANGLE TEETH) PROPRIETARY AND CONFIDENTIAL TOLERANCING PER: COMMENTS: THE INFORMATION CONTAINED IN THIS MATERIAL DRAWING IS THE SOLE PROPERTY OF SIZE DWG. NO. REV FREEDOM FIGHTERS. ANY REPRODUCTION IN PART OR AS A WHOLE FINISH WITHOUT THE WRITTEN PERMISSION OF NEXT ASSY USED ON B T11-100 0 FREEDOM FIGHTERS IS PROHIBITED. APPLICATION DO NOT SCALE DRAWING SCALE: 1:2 WEIGHT: SHEET 1 OF 12 4 3 2 1 4 3 2 1

B B

12.73

SECTION A-A SCALE 4 : 1

28.38

5.08

A A A A UNLESS OTHERWISE SPECIFIED: NAME DATE

DIMENSIONS ARE IN MILLIMETERS DRAWN TOLERANCES: FRACTIONAL CHECKED TITLE: ANGULAR: MACH BEND ENG APPR. TWO PLACE DECIMAL THREE PLACE DECIMAL MFG APPR. PAWL TOGGLE

INTERPRET GEOMETRIC Q.A. PROPRIETARY AND CONFIDENTIAL TOLERANCING PER: COMMENTS: THE INFORMATION CONTAINED IN THIS MATERIAL SIZE DWG. NO. REV DRAWING IS THE SOLE PROPERTY OF STAINLESS STEEL FREEDOM FIGHTERS. ANY REPRODUCTION IN PART OR AS A WHOLE FINISH WITHOUT THE WRITTEN PERMISSION OF NEXT ASSY USED ON B T11-110 0 FREEDOM FIGHTERS IS PROHIBITED. APPLICATION DO NOT SCALE DRAWING SCALE: 1:2 WEIGHT: SHEET 2 OF 12 4 3 2 1 4 3 2 1

1.97 1.59

B B

11.95

4.93

A A UNLESS OTHERWISE SPECIFIED: NAME DATE

DIMENSIONS ARE IN MILLIMETERS DRAWN TOLERANCES: FRACTIONAL CHECKED TITLE: ANGULAR: MACH BEND ENG APPR. TWO PLACE DECIMAL THREE PLACE DECIMAL MFG APPR. TOGGLE

INTERPRET GEOMETRIC Q.A. PROPRIETARY AND CONFIDENTIAL TOLERANCING PER: HANDLE COMMENTS: THE INFORMATION CONTAINED IN THIS MATERIAL SIZE DWG. NO. REV DRAWING IS THE SOLE PROPERTY OF STAINLESS STEEL FREEDOM FIGHTERS. ANY REPRODUCTION IN PART OR AS A WHOLE FINISH WITHOUT THE WRITTEN PERMISSION OF NEXT ASSY USED ON B T11-115 0 FREEDOM FIGHTERS IS PROHIBITED. APPLICATION DO NOT SCALE DRAWING SCALE: 1:2 WEIGHT: SHEET 3 OF 12 4 3 2 1 4 3 2 1

12.86 A B 3.18 B

65.00 44.45 34.93

A SECTION A-A SCALE 1.5 : 1 A A UNLESS OTHERWISE SPECIFIED: NAME DATE

DIMENSIONS ARE IN MILLIMETERS DRAWN TOLERANCES: FRACTIONAL CHECKED TITLE: ANGULAR: MACH BEND ENG APPR. TWO PLACE DECIMAL THREE PLACE DECIMAL MFG APPR. SPROCKET PLATE

INTERPRET GEOMETRIC Q.A. PROPRIETARY AND CONFIDENTIAL TOLERANCING PER: COMMENTS: THE INFORMATION CONTAINED IN THIS MATERIAL SIZE DWG. NO. REV DRAWING IS THE SOLE PROPERTY OF STAINLESS STEEL FREEDOM FIGHTERS. ANY REPRODUCTION IN PART OR AS A WHOLE FINISH WITHOUT THE WRITTEN PERMISSION OF NEXT ASSY USED ON B T11-120 0 FREEDOM FIGHTERS IS PROHIBITED. APPLICATION DO NOT SCALE DRAWING SCALE: 1:2 WEIGHT: SHEET 4 OF 12 4 3 2 1 4 3 2 1

3.18

B B

A 50.02 79.65

B

A A UNLESS OTHERWISE SPECIFIED: NAME DATE DETAIL A DIMENSIONS ARE IN MILLIMETERS DRAWN SCALE 3 : 1 TOLERANCES: FRACTIONAL CHECKED TITLE: ANGULAR: MACH BEND ENG APPR. TWO PLACE DECIMAL THREE PLACE DECIMAL MFG APPR. 18T SPROCKET W/ DETAIL B INTERPRET GEOMETRIC Q.A. SCALE 6 : 1 PROPRIETARY AND CONFIDENTIAL TOLERANCING PER: TRIANGLE TEETH COMMENTS: THE INFORMATION CONTAINED IN THIS MATERIAL SIZE DWG. NO. REV DRAWING IS THE SOLE PROPERTY OF STAINLESS STEEL FREEDOM FIGHTERS. ANY REPRODUCTION IN PART OR AS A WHOLE FINISH WITHOUT THE WRITTEN PERMISSION OF NEXT ASSY USED ON B T11-125A 0 FREEDOM FIGHTERS IS PROHIBITED. APPLICATION DO NOT SCALE DRAWING SCALE: 1:2 WEIGHT: SHEET 5 OF 12 4 3 2 1 4 3 2 1

3.18

B B

A 50.02 95.95

B

A A UNLESS OTHERWISE SPECIFIED: NAME DATE

DIMENSIONS ARE IN MILLIMETERS DRAWN TOLERANCES: FRACTIONAL CHECKED TITLE: ANGULAR: MACH BEND ENG APPR. TWO PLACE DECIMAL THREE PLACE DECIMAL MFG APPR. 22T SPROCKET W/

INTERPRET GEOMETRIC Q.A. PROPRIETARY AND CONFIDENTIAL TOLERANCING PER: TRIANGLE TEETH DETAIL B COMMENTS: THE INFORMATION CONTAINED IN THIS MATERIAL SIZE DWG. NO. REV SCALE 6 : 1 DRAWING IS THE SOLE PROPERTY OF STAINLESS STEEL FREEDOM FIGHTERS. ANY REPRODUCTION IN PART OR AS A WHOLE FINISH DETAIL A WITHOUT THE WRITTEN PERMISSION OF NEXT ASSY USED ON B T11-125B 0 SCALE 3 : 1 FREEDOM FIGHTERS IS PROHIBITED. APPLICATION DO NOT SCALE DRAWING SCALE: 1:2 WEIGHT: SHEET 6 OF 12 4 3 2 1 4 3 2 1

3.18

B B

A 50.10 112.21

B

DETAIL A A SCALE 2 : 1 A UNLESS OTHERWISE SPECIFIED: NAME DATE

DIMENSIONS ARE IN MILLIMETERS DRAWN TOLERANCES: FRACTIONAL CHECKED TITLE: ANGULAR: MACH BEND ENG APPR. TWO PLACE DECIMAL THREE PLACE DECIMAL MFG APPR. 26T SPROCKET W/

INTERPRET GEOMETRIC Q.A. PROPRIETARY AND CONFIDENTIAL TOLERANCING PER: TRIANGLE TEETH DETAIL B COMMENTS: THE INFORMATION CONTAINED IN THIS MATERIAL SIZE DWG. NO. REV DRAWING IS THE SOLE PROPERTY OF STAINLESS STEEL SCALE 6 : 1 FREEDOM FIGHTERS. ANY REPRODUCTION IN PART OR AS A WHOLE FINISH WITHOUT THE WRITTEN PERMISSION OF NEXT ASSY USED ON B T11-125C 0 FREEDOM FIGHTERS IS PROHIBITED. APPLICATION DO NOT SCALE DRAWING SCALE: 1:2 WEIGHT: SHEET 7 OF 12 4 3 2 1 4 3 2 1

B 3.97 B

50.02 65.02

A

A A UNLESS OTHERWISE SPECIFIED: NAME DATE DETAIL A DIMENSIONS ARE IN MILLIMETERS DRAWN TOLERANCES: SCALE 8 : 1 FRACTIONAL CHECKED TITLE: ANGULAR: MACH BEND ENG APPR. TWO PLACE DECIMAL THREE PLACE DECIMAL MFG APPR. SPACER -

INTERPRET GEOMETRIC Q.A. PROPRIETARY AND CONFIDENTIAL TOLERANCING PER: TRIANGLE COMMENTS: THE INFORMATION CONTAINED IN THIS MATERIAL SIZE DWG. NO. REV DRAWING IS THE SOLE PROPERTY OF STAINLESS STEEL FREEDOM FIGHTERS. ANY REPRODUCTION IN PART OR AS A WHOLE FINISH WITHOUT THE WRITTEN PERMISSION OF NEXT ASSY USED ON B T11-130 0 FREEDOM FIGHTERS IS PROHIBITED. APPLICATION DO NOT SCALE DRAWING SCALE: 1:2 WEIGHT: SHEET 8 OF 12 4 3 2 1 4 3 2 1

B 5.08 B

37.11

45.72

A

A A UNLESS OTHERWISE SPECIFIED: NAME DATE DETAIL A DIMENSIONS ARE IN INCHES DRAWN TOLERANCES: SCALE 8 : 1 FRACTIONAL CHECKED TITLE: ANGULAR: MACH BEND ENG APPR. TWO PLACE DECIMAL THREE PLACE DECIMAL MFG APPR. PAWL CASE -

INTERPRET GEOMETRIC Q.A. PROPRIETARY AND CONFIDENTIAL TOLERANCING PER: TRIANGLE COMMENTS: THE INFORMATION CONTAINED IN THIS MATERIAL SIZE DWG. NO. REV DRAWING IS THE SOLE PROPERTY OF STAINLESS STEEL FREEDOM FIGHTERS. ANY REPRODUCTION IN PART OR AS A WHOLE FINISH WITHOUT THE WRITTEN PERMISSION OF NEXT ASSY USED ON B T11-135 0 FREEDOM FIGHTERS IS PROHIBITED. APPLICATION DO NOT SCALE DRAWING SCALE: 1:2 WEIGHT: SHEET 9 OF 12 4 3 2 1 4 3 2 1

B B 5.08

8.76

0.03 5.08

4.83

A A UNLESS OTHERWISE SPECIFIED: NAME DATE

DIMENSIONS ARE IN MILLIMETERS DRAWN TOLERANCES: FRACTIONAL CHECKED TITLE: ANGULAR: MACH BEND ENG APPR. TWO PLACE DECIMAL THREE PLACE DECIMAL MFG APPR. PAWL SPRING

INTERPRET GEOMETRIC Q.A. PROPRIETARY AND CONFIDENTIAL TOLERANCING PER: COMMENTS: THE INFORMATION CONTAINED IN THIS MATERIAL SIZE DWG. NO. REV DRAWING IS THE SOLE PROPERTY OF STAINLESS STEEL FREEDOM FIGHTERS. ANY REPRODUCTION IN PART OR AS A WHOLE FINISH WITHOUT THE WRITTEN PERMISSION OF NEXT ASSY USED ON B T11-140 0 FREEDOM FIGHTERS IS PROHIBITED. APPLICATION DO NOT SCALE DRAWING SCALE: 1:2 WEIGHT: SHEET 10 OF 12 4 3 2 1 4 3 2 1

12.60 6.35 B B

10.27

A

DETAIL A A SCALE 16 : 1 A UNLESS OTHERWISE SPECIFIED: NAME DATE

DIMENSIONS ARE IN MILLIMETERS DRAWN TOLERANCES: FRACTIONAL CHECKED TITLE: ANGULAR: MACH BEND ENG APPR. TWO PLACE DECIMAL THREE PLACE DECIMAL MFG APPR. PAWL -

INTERPRET GEOMETRIC Q.A. PROPRIETARY AND CONFIDENTIAL TOLERANCING PER: TRIANGLE COMMENTS: THE INFORMATION CONTAINED IN THIS MATERIAL SIZE DWG. NO. REV DRAWING IS THE SOLE PROPERTY OF STAINLESS STEEL FREEDOM FIGHTERS. ANY REPRODUCTION IN PART OR AS A WHOLE FINISH WITHOUT THE WRITTEN PERMISSION OF NEXT ASSY USED ON B T11-145 0 FREEDOM FIGHTERS IS PROHIBITED. APPLICATION DO NOT SCALE DRAWING SCALE: 1:2 WEIGHT: SHEET 11 OF 12 4 3 2 1 4 3 2 1

3.18

B B

17.78 53.98

A A UNLESS OTHERWISE SPECIFIED: NAME DATE

DIMENSIONS ARE IN MILLIMETERS DRAWN TOLERANCES: FRACTIONAL CHECKED TITLE: ANGULAR: MACH BEND ENG APPR. TWO PLACE DECIMAL THREE PLACE DECIMAL MFG APPR. PAWL DISC

INTERPRET GEOMETRIC Q.A. PROPRIETARY AND CONFIDENTIAL TOLERANCING PER: COMMENTS: THE INFORMATION CONTAINED IN THIS MATERIAL SIZE DWG. NO. REV DRAWING IS THE SOLE PROPERTY OF STAINLESS STEEL FREEDOM FIGHTERS. ANY REPRODUCTION IN PART OR AS A WHOLE FINISH WITHOUT THE WRITTEN PERMISSION OF NEXT ASSY USED ON B T11-150 0 FREEDOM FIGHTERS IS PROHIBITED. APPLICATION DO NOT SCALE DRAWING SCALE: 1:2 WEIGHT: SHEET 12 OF 12 4 3 2 1 4 3 2 1

ITEM PART NUMBER DESCRIPTION QTY. 7 8 9 10 11 12 14 NO. 1 T11-110 PAWL TOGGLE 1 5/8" FACE MOUNT SHAFT 2 9677T23 COLLAR 1 18-8,1/4"OD X 1/8" 3 92320A340 SPACER FOR #6 SCREW 1 18-8, 1/8 X 5/16" CLEVIS 4 92390A070 PIN 1 5 90692A084 1/16 X 7/16" SLOTTED 1 1 SPRING PIN B 6 T11-115 TOGGLE HANDLE 1 B 5/8" SHAFT COLLAR W/ 2 7 6462K18 SET SCREW 1 INTERNAL RETAINING 8 99142A520 RING, 1-3/8" ID 1 3 BALL BEARING - R10-2RS, 9 60355K705 5/8" SHAFT 1 3/32 X 7/16" SLOTTED 4 10 90692A142 SPRING PIN 3 11 T11-120 SPROCKET PLATE 1 5 18T SPROCKET W/ GEAR 12 T11-225A TEETH 1 13 T11-225B 22T SPROCKET W/ GEAR 1 6 TEETH 26T SPROCKET W/ GEAR 14 T11-225C TEETH 1 10-24 X 5/8" SOCKET 15 92220A164 HEAD CAP SCREW 2 4-40 FLUSH-MOUNT PRESS 16 94674A490 FIT NUTS, 0.062" 3 17 T11-230 SPACER - GEAR 1 18 T11-235 PAWL CASE - GEAR 1 19 T11-140 PAWL SPRING 2 20 T11-245 PAWL - GEAR 2 21 T11-150 PAWL DISC 1 4-40 X 3/8" SOCKET HEAD A 22 91251A108 CAP SCREW 3 A UNLESS OTHERWISE SPECIFIED: NAME DATE

DIMENSIONS ARE IN MILLIMETERS DRAWN TOLERANCES: FRACTIONAL CHECKED TITLE: ANGULAR: MACH BEND ENG APPR. 13 17 16 15 18 19 20 21 22 TWO PLACE DECIMAL TWO-WAY RATCHET THREE PLACE DECIMAL MFG APPR. INTERPRET GEOMETRIC Q.A. (GEAR TEETH) PROPRIETARY AND CONFIDENTIAL TOLERANCING PER: COMMENTS: THE INFORMATION CONTAINED IN THIS MATERIAL DRAWING IS THE SOLE PROPERTY OF SIZE DWG. NO. REV FREEDOM FIGHTERS. ANY REPRODUCTION IN PART OR AS A WHOLE FINISH WITHOUT THE WRITTEN PERMISSION OF NEXT ASSY USED ON B T11-200 0 FREEDOM FIGHTERS IS PROHIBITED. APPLICATION DO NOT SCALE DRAWING SCALE: 1:5 WEIGHT: SHEET 1 OF 12 4 3 2 1 4 3 2 1

B B

12.73

SECTION A-A SCALE 4 : 1

5.08

A A

A A UNLESS OTHERWISE SPECIFIED: NAME DATE

DIMENSIONS ARE IN MILLIMETERS DRAWN TOLERANCES: FRACTIONAL CHECKED TITLE: ANGULAR: MACH BEND ENG APPR. TWO PLACE DECIMAL THREE PLACE DECIMAL MFG APPR. PAWL TOGGLE

INTERPRET GEOMETRIC Q.A. PROPRIETARY AND CONFIDENTIAL TOLERANCING PER: COMMENTS: THE INFORMATION CONTAINED IN THIS MATERIAL SIZE DWG. NO. REV DRAWING IS THE SOLE PROPERTY OF STAINLESS STEEL FREEDOM FIGHTERS. ANY REPRODUCTION IN PART OR AS A WHOLE FINISH WITHOUT THE WRITTEN PERMISSION OF NEXT ASSY USED ON B T11-110 0 FREEDOM FIGHTERS IS PROHIBITED. APPLICATION DO NOT SCALE DRAWING SCALE: 1:5 WEIGHT: SHEET 2 OF 12 4 3 2 1 4 3 2 1

1.97 1.59

B B

11.95

4.93

A A UNLESS OTHERWISE SPECIFIED: NAME DATE

DIMENSIONS ARE IN MILLIMETERS DRAWN TOLERANCES: FRACTIONAL CHECKED TITLE: ANGULAR: MACH BEND ENG APPR. TWO PLACE DECIMAL THREE PLACE DECIMAL MFG APPR. TOGGLE

INTERPRET GEOMETRIC Q.A. PROPRIETARY AND CONFIDENTIAL TOLERANCING PER: HANDLE COMMENTS: THE INFORMATION CONTAINED IN THIS MATERIAL SIZE DWG. NO. REV DRAWING IS THE SOLE PROPERTY OF STAINLESS STEEL FREEDOM FIGHTERS. ANY REPRODUCTION IN PART OR AS A WHOLE FINISH WITHOUT THE WRITTEN PERMISSION OF NEXT ASSY USED ON B T11-115 0 FREEDOM FIGHTERS IS PROHIBITED. APPLICATION DO NOT SCALE DRAWING SCALE: 1:5 WEIGHT: SHEET 3 OF 12 4 3 2 1 4 3 2 1

B A 12.86 B 3.18

65.00 44.45 34.93

A SECTION A-A SCALE 1.5 : 1 A A UNLESS OTHERWISE SPECIFIED: NAME DATE

DIMENSIONS ARE IN MILLIMETERS DRAWN TOLERANCES: FRACTIONAL CHECKED TITLE: ANGULAR: MACH BEND ENG APPR. TWO PLACE DECIMAL THREE PLACE DECIMAL MFG APPR. SPROCKET PLATE

INTERPRET GEOMETRIC Q.A. PROPRIETARY AND CONFIDENTIAL TOLERANCING PER: COMMENTS: THE INFORMATION CONTAINED IN THIS MATERIAL SIZE DWG. NO. REV DRAWING IS THE SOLE PROPERTY OF STAINLESS STEEL FREEDOM FIGHTERS. ANY REPRODUCTION IN PART OR AS A WHOLE FINISH WITHOUT THE WRITTEN PERMISSION OF NEXT ASSY USED ON B T11-120 0 FREEDOM FIGHTERS IS PROHIBITED. APPLICATION DO NOT SCALE DRAWING SCALE: 1:5 WEIGHT: SHEET 4 OF 12 4 3 2 1 4 3 2 1

3.25

B B

A 49.00 79.65

B

A A UNLESS OTHERWISE SPECIFIED: NAME DATE

DIMENSIONS ARE IN MILLIMETERS DRAWN TOLERANCES: FRACTIONAL CHECKED TITLE: ANGULAR: MACH BEND ENG APPR. TWO PLACE DECIMAL DETAIL A THREE PLACE DECIMAL MFG APPR. 18T SPROCKET

SCALE 3 : 1 INTERPRET GEOMETRIC Q.A. PROPRIETARY AND CONFIDENTIAL TOLERANCING PER: W/ GEAR TEETH COMMENTS: THE INFORMATION CONTAINED IN THIS MATERIAL SIZE DWG. NO. REV DETAIL B DRAWING IS THE SOLE PROPERTY OF STAINLESS STEEL FREEDOM FIGHTERS. ANY SCALE 6 : 1 REPRODUCTION IN PART OR AS A WHOLE FINISH WITHOUT THE WRITTEN PERMISSION OF NEXT ASSY USED ON B T11-225A 0 FREEDOM FIGHTERS IS PROHIBITED. APPLICATION DO NOT SCALE DRAWING SCALE: 1:5 WEIGHT: SHEET 5 OF 12 4 3 2 1 4 3 2 1

3.17

B B

A 49.00 95.95

B

A A UNLESS OTHERWISE SPECIFIED: NAME DATE

DIMENSIONS ARE IN MILLIMETERS DRAWN TOLERANCES: FRACTIONAL CHECKED TITLE: ANGULAR: MACH BEND ENG APPR. TWO PLACE DECIMAL THREE PLACE DECIMAL MFG APPR. 22T SPROCKET

INTERPRET GEOMETRIC Q.A. PROPRIETARY AND CONFIDENTIAL TOLERANCING PER: W/ GEAR TEETH COMMENTS: THE INFORMATION CONTAINED IN THIS MATERIAL SIZE DWG. NO. REV DETAIL B DRAWING IS THE SOLE PROPERTY OF STAINLESS STEEL DETAIL A FREEDOM FIGHTERS. ANY SCALE 3 : 1 SCALE 6 : 1 REPRODUCTION IN PART OR AS A WHOLE FINISH WITHOUT THE WRITTEN PERMISSION OF NEXT ASSY USED ON B T11-225B 0 FREEDOM FIGHTERS IS PROHIBITED. APPLICATION DO NOT SCALE DRAWING SCALE: 1:5 WEIGHT: SHEET 6 OF 12 4 3 2 1 4 3 2 1

3.17

B B

A 49.00 112.21

B

A A UNLESS OTHERWISE SPECIFIED: NAME DATE

DIMENSIONS ARE IN MILLIMETERS DRAWN TOLERANCES: FRACTIONAL CHECKED TITLE: ANGULAR: MACH BEND ENG APPR. TWO PLACE DECIMAL THREE PLACE DECIMAL 26T SPROCKET DETAIL B MFG APPR. DETAIL A INTERPRET GEOMETRIC Q.A. SCALE 6 : 1 PROPRIETARY AND CONFIDENTIAL TOLERANCING PER: W/ GEAR TEETH SCALE 3 : 1 COMMENTS: THE INFORMATION CONTAINED IN THIS MATERIAL SIZE DWG. NO. REV DRAWING IS THE SOLE PROPERTY OF STAINLESS STEEL FREEDOM FIGHTERS. ANY REPRODUCTION IN PART OR AS A WHOLE FINISH WITHOUT THE WRITTEN PERMISSION OF NEXT ASSY USED ON B T11-225C 0 FREEDOM FIGHTERS IS PROHIBITED. APPLICATION DO NOT SCALE DRAWING SCALE: 1:5 WEIGHT: SHEET 7 OF 12 4 3 2 1 4 3 2 1

3.97

B B

49.00 65.02

A

A A UNLESS OTHERWISE SPECIFIED: NAME DATE

DIMENSIONS ARE IN MILLIMETERS DRAWN TOLERANCES: FRACTIONAL CHECKED TITLE: ANGULAR: MACH BEND ENG APPR. TWO PLACE DECIMAL THREE PLACE DECIMAL MFG APPR. SPACER - GEAR

INTERPRET GEOMETRIC Q.A. PROPRIETARY AND CONFIDENTIAL TOLERANCING PER: DETAIL A COMMENTS: THE INFORMATION CONTAINED IN THIS MATERIAL SIZE DWG. NO. REV SCALE 8 : 1 DRAWING IS THE SOLE PROPERTY OF STAINLESS STEEL FREEDOM FIGHTERS. ANY REPRODUCTION IN PART OR AS A WHOLE FINISH WITHOUT THE WRITTEN PERMISSION OF NEXT ASSY USED ON B T11-230 0 FREEDOM FIGHTERS IS PROHIBITED. APPLICATION DO NOT SCALE DRAWING SCALE: 1:5 WEIGHT: SHEET 8 OF 12 4 3 2 1 4 3 2 1

5.08

B B

45.72 45.22

A

A A UNLESS OTHERWISE SPECIFIED: NAME DATE

DETAIL A DIMENSIONS ARE IN MILLIMETERS DRAWN SCALE 8 : 1 TOLERANCES: FRACTIONAL CHECKED TITLE: ANGULAR: MACH BEND ENG APPR. TWO PLACE DECIMAL THREE PLACE DECIMAL MFG APPR. PAWL CASE -

INTERPRET GEOMETRIC Q.A. PROPRIETARY AND CONFIDENTIAL TOLERANCING PER: GEAR COMMENTS: THE INFORMATION CONTAINED IN THIS MATERIAL SIZE DWG. NO. REV DRAWING IS THE SOLE PROPERTY OF STAINLESS STEEL FREEDOM FIGHTERS. ANY REPRODUCTION IN PART OR AS A WHOLE FINISH WITHOUT THE WRITTEN PERMISSION OF NEXT ASSY USED ON B T11-235 0 FREEDOM FIGHTERS IS PROHIBITED. APPLICATION DO NOT SCALE DRAWING SCALE: 1:5 WEIGHT: SHEET 9 OF 12 4 3 2 1 4 3 2 1

B B 5.08

8.76

0.03 5.08

4.83

A A UNLESS OTHERWISE SPECIFIED: NAME DATE

DIMENSIONS ARE IN MILLIMETERS DRAWN TOLERANCES: FRACTIONAL CHECKED TITLE: ANGULAR: MACH BEND ENG APPR. TWO PLACE DECIMAL THREE PLACE DECIMAL MFG APPR. PAWL SPRING

INTERPRET GEOMETRIC Q.A. PROPRIETARY AND CONFIDENTIAL TOLERANCING PER: COMMENTS: THE INFORMATION CONTAINED IN THIS MATERIAL SIZE DWG. NO. REV DRAWING IS THE SOLE PROPERTY OF STAINLESS STEEL FREEDOM FIGHTERS. ANY REPRODUCTION IN PART OR AS A WHOLE FINISH WITHOUT THE WRITTEN PERMISSION OF NEXT ASSY USED ON B T11-140 0 FREEDOM FIGHTERS IS PROHIBITED. APPLICATION DO NOT SCALE DRAWING SCALE: 1:2 WEIGHT: SHEET 10 OF 12 4 3 2 1 4 3 2 1

B 12.18 6.27 B

10.49

A

A A UNLESS OTHERWISE SPECIFIED: NAME DATE

DIMENSIONS ARE IN MILLIMETERS DRAWN TOLERANCES: FRACTIONAL CHECKED TITLE: ANGULAR: MACH BEND ENG APPR. TWO PLACE DECIMAL DETAIL A THREE PLACE DECIMAL MFG APPR. PAWL - GEAR SCALE 16 : 1 INTERPRET GEOMETRIC Q.A. PROPRIETARY AND CONFIDENTIAL TOLERANCING PER: COMMENTS: THE INFORMATION CONTAINED IN THIS MATERIAL SIZE DWG. NO. REV DRAWING IS THE SOLE PROPERTY OF STAINLESS STEEL FREEDOM FIGHTERS. ANY REPRODUCTION IN PART OR AS A WHOLE FINISH WITHOUT THE WRITTEN PERMISSION OF NEXT ASSY USED ON B T11-245 0 FREEDOM FIGHTERS IS PROHIBITED. APPLICATION DO NOT SCALE DRAWING SCALE: 1:5 WEIGHT: SHEET 11 OF 12 4 3 2 1 4 3 2 1

3.18

B B

17.78 53.98

A A UNLESS OTHERWISE SPECIFIED: NAME DATE

DIMENSIONS ARE IN MILLIMETERS DRAWN TOLERANCES: FRACTIONAL CHECKED TITLE: ANGULAR: MACH BEND ENG APPR. TWO PLACE DECIMAL THREE PLACE DECIMAL MFG APPR. PAWL DISC

INTERPRET GEOMETRIC Q.A. PROPRIETARY AND CONFIDENTIAL TOLERANCING PER: COMMENTS: THE INFORMATION CONTAINED IN THIS MATERIAL SIZE DWG. NO. REV DRAWING IS THE SOLE PROPERTY OF STAINLESS STEEL FREEDOM FIGHTERS. ANY REPRODUCTION IN PART OR AS A WHOLE FINISH WITHOUT THE WRITTEN PERMISSION OF NEXT ASSY USED ON B T11-150 0 FREEDOM FIGHTERS IS PROHIBITED. APPLICATION DO NOT SCALE DRAWING SCALE: 1:2 WEIGHT: SHEET 12 OF 12 4 3 2 1