Design of an Inversion Mechanism A Major Qualifying Project proposal to be submitted to the faculty of Worcester Polytechnic Institute in partial fulfillment of the requirements for the Degree of Bachelor of Science Submitted by: Chelsea Brown Matthew Dooman Sarah Lax Submitted to: Project Advisor: Professor Robert Norton Project Sponsor: Corey Maynard April 2011 Abstract The goal of this project was to create a mechanism that picks up a part, inverts it 180 degrees, and places it in a new location in its new orientation. This task was completed through the use of the design process. Ideas were brainstormed, drawn up, and evaluated. One design that was deemed a viable option was then modeled using Pro/ENGINEER. After modeling, the design was analyzed for various attributes such as stress, deflection, and fatigue failure. The result of this work is the creation of an inverting mechanism that uses a system of bevel gears with grippers attached to hold, rotate, and move the part. With the part in the grippers, as the rotating gear moves along the stationary gear, the part is flipped over 180 degrees. The part is brought to the grippers and removed from the grippers by the use of tooling that is stationary above the pick-up and drop-off locations. This mechanism provides a new way to access both sides of the part being moved as well as new tooling that could be modified and applied in several other applications. 2 Table of Contents Abstract ......................................................................................................................................................... 2 List of Figures ............................................................................................................................................... 5 List of Tables ................................................................................................................................................ 6 Introduction ................................................................................................................................................... 7 Problem Statement ........................................................................................................................................ 7 Task Specifications ....................................................................................................................................... 7 Background ................................................................................................................................................... 8 Grippers ..................................................................................................................................................... 8 Gear Backlash ............................................................................................................................................ 9 Preliminary Designs................................................................................................................................... 9 Linkages ................................................................................................................................................ 9 Carousel .............................................................................................................................................. 12 Final Design ................................................................................................................................................ 14 Description ............................................................................................................................................... 14 Annotated Pictures and Parts List ....................................................................................................... 14 Gripper Assembly .................................................................................................................................... 19 Solenoid and Rail Assembly .................................................................................................................... 27 Solenoid .............................................................................................................................................. 27 Rail and Guide Block .......................................................................................................................... 27 Activator Assembly ................................................................................................................................. 30 Rail Attachment .................................................................................................................................. 32 Leveling Slider .................................................................................................................................... 33 Vacuum Slider .................................................................................................................................... 35 Gripper Interaction Cam ..................................................................................................................... 37 Gear Assembly ........................................................................................................................................ 37 Gears ................................................................................................................................................... 37 Arms .................................................................................................................................................... 39 Bearings .............................................................................................................................................. 39 Manufacturing ............................................................................................................................................. 40 Assembly .................................................................................................................................................... 43 Results and Analysis ................................................................................................................................... 54 Bolts, Screws and Pin .............................................................................................................................. 55 Other Parts ............................................................................................................................................... 57 Springs ..................................................................................................................................................... 58 Timing ..................................................................................................................................................... 58 Conclusions ................................................................................................................................................. 60 3 Recommendations ....................................................................................................................................... 61 Bibliography ............................................................................................................................................... 62 Appendix A: Calculations ........................................................................................................................... 63 Gear Arm Bolt Analysis .......................................................................................................................... 63 Gripper Pin Clearance.............................................................................................................................. 65 Gripper Base Bolts ................................................................................................................................... 67 Vacuum Slider Pin ................................................................................................................................... 68 Leveling Slider Pin .................................................................................................................................. 69 Yoke-to-Rail Bolt .................................................................................................................................... 71 Gear Arms ................................................................................................................................................ 72 Gear Backlash .......................................................................................................................................... 86 Gripper Arms Analysis ............................................................................................................................ 88 Activator – Bending due to Leveling Slider .......................................................................................... 108 Appendix B: Standard Parts ...................................................................................................................... 111 Bearings ................................................................................................................................................. 111 Outside gear arm bearing .................................................................................................................. 111 Inside gear arm bearing ....................................................................................................................