Jib Transfer Bench – P13031

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# Jib Transfer Bench – P13031

## Jib Transfer Bench – P13031

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##### Presentation Transcript

1. Jib Transfer Bench – P13031 Detailed Design Review 3/4/2013 Mike Walsh Nick Davis Charles Kowalyshyn Zeb Koch

2. Agenda • Project Introduction • Review of Customer Needs • CAD Model and Subsystem Analysis • Calculations • System Interfaces • Schematics • BOM • Risk Assessment

3. Project Introduction • Tasked with creating a device to: • Move a disabled jib trimmer on a Sonar Sailboat from Port to Starboard

4. Specific Customer Needs • Gary & Zak • No leg mobility / core support • Desires to be fully secured • Cindy • Partial leg & core strength • Desires freedom to exit seat when necessary • Limited footprint available due to P13032’s chair • Cindy needs the option to sail with Gold Medal Chair or as a standalone device • Height differences to consider

5. P12032’s Gold Medal Chair

6. P12032’s Gold Medal Chair

7. Customer Needs Mapped to Metrics

8. Test Plan

9. Test Plan (continued)

11. Support Bar • Multipurpose Aluminum (Alloy 6061) Rectangular Tube

12. Guide Rail

13. Support Leg

14. Platform

15. Guide Rail Support

16. Seat Bracket Install

17. Seat Install

18. Hand Hold Subsystem

19. Hand Hold Install

20. Seat Bracket Calculations • Assume concentrated load for weight of Seat Bracket at “X” (Center of Gravity) • Free Body Diagram: Tx Ty M Wseat Wseat By Bx

21. Seat Bracket Calculations Sum the Forces and Moments • ΣFx = 0 = Tx + Bx • ΣFy = 0 = Ty + By – Ws – Wp • ΣM = 0 = M – TxYt–TyXb – Ws(Xws-Xb)- Wp(Xwp- Xb) • 3 equations • 4 unknowns • Mmax=131 ft-lb Tx Yt Yws Ty Ws M Ywp Wp Xb Xws By Xwp Bx

22. Deriving the 4th Equation • Simulated the bracket as a cantilevered beam • Used Superposition of Table A9 in Shigley’s • Relating Ty to By, Ws, Wp • Sum of deflections due to forces at B = 0 Wseat Wperson M Bx By Tx Ty Yt Xb Xws Xwp

23. Matlab Function JTB2() - Solves the four equations, with M=131 ft-lb • >> JTB2() • Top Bar X-Force: -32.436667 lbs • Top Bar Y-Force: 152.916899 lbs • Bottom Bar X-Force: 32.436667 lbs • Bottom Bar Y-Force: 123.683101 lbs • Top Bar Total Force: 156.319274 lbs • Bottom Bar Total Force: 127.865737 lbs • Top Bar Deflection: 0.252938 inches • Max Yield Stress : 65300.000000 psi • Top Bar Max Stress : 38214.121245 psi • Pass!-Top Bar • The Stress Factor of Safety is 1.708792

24. Top Bar Deflection • Maximum Deflection when seat is at center position • Stainless Steel – 1” Diameter • δmax= FL3/(48EI) where I = πr4/4 • Fmax=4σπ/DL Net Force Top Traveler Bar R2 R1

25. Seat Bracket Stresses • The stresses in the Seat Bracket are very small. • Second moment of inertia is very large • Large C-S area • Assume two beams and check stress in both Tx σ= My/I I=1/12 * b * h3 b= 6.5 inches h=.5 inches y=.25 inches Wp Yt Xwp

26. Matlab Function JTB2() Seat Bracket- Back • Max Yield Stress : 300.133006 psi Seat Bracket- Bottom • Max Yield Stress : 894.400000 psi

27. System Interfaces • Generated a list identifying: • All major components • How they interact with one another • (i.e. “foot-bone connected to the leg-bone”) • Possible critical Loads

28. System interfaces (cont.)

29. System interfaces (cont.)

30. System interfaces (cont.)

31. Purchase System • 3-1 Purchase System Breakdown Lines wrap around to center position Port Starboard Seat Bracket

32. Purchase System Representation

33. Bill Of Materials Refer to BOM + Budget doc

34. Seat Selection • Zak & Gary • Searched dozens of bucket seats • Size and corrosion requirements constrained selection • Settled on RCI High-Back Aluminum Racing Seat with vinyl cover • Relatively cheap • Cindy • Constrained with footprint due to P13032’s chair • Did not find suitable stool on the market • Currently looking into stadium seats

35. Risk Assessment (Top 5) • 1. Budget • 2. Interfacing with other team’s base plate • 3. Brake – Rotational motion • 4. Handhold Design • 5. Inability to accept user’s cushion due to size constraints

36. Budget Analysis • Projected: \$2,000.00 • Cindy’s System: \$2,724.37 • Zak and Gary’s System:\$2,915.85 • Not included: • Shipping costs • Machining of aluminum plates • Corrosion testing • Delivery to customer

37. High Cost Items • Purchase System: \$412.50 • 6061 Aluminum: \$539.80 • 47% of Budget • Metals (tubes, plates) • BOM has from internet suppliers’ numbers • Looking locally to reduce shipping and price - Klein Steel

38. Interface (captains chair) • For use with P13032’s Captain’s Chair, the design changes: • Repeated bolt pattern in P13032’s base plate • Less handholds are available • Need Installation procedure when used together

39. Rotational Motion Braking Mechanism • Currently, the brake for the Lazy Susan is undefined. • Working on several ideas Friction Plate Force-Action Clamp Ratchet & Pawl

40. Rotation Brake • Curved rubber wedge into Lazy Susan turntable

41. Handhold Design • Working to improve the previous team’s solution • Working hand-in-hand(hold) with group P13032 to design a standard handhold