Jib Transfer Bench – P13031

Detailed Design Review 3/4/2013

Mike WalshNick Davis

Charles KowalyshynZeb Koch

- Project Introduction- Review of Customer Needs- CAD Model and Subsystem Analysis- Calculations- System Interfaces- Schematics- BOM- Risk Assessment

Agenda

Tasked with creating a device to:◦ Move a disabled jib trimmer on a Sonar Sailboat

from Port to Starboard

Project Introduction

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

Specific Customer Needs

P12032’s Gold Medal Chair

P12032’s Gold Medal Chair

Customer Needs Mapped to Metrics

Test Plan

Test Plan (continued)

CAD Model

Support Bar Multipurpose Aluminum (Alloy 6061)

Rectangular Tube

Guide Rail

Support Leg

Platform

Guide Rail Support

Seat Bracket Install

Seat Install

Hand Hold Subsystem

Hand Hold Install

Assume concentrated load for weight of Seat Bracket at “X” (Center of Gravity)

Free Body Diagram:

Seat Bracket Calculations

By

Tx

Ty

Bx

Wseat

Wseat

M

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

Seat Bracket Calculations

By

Tx

Ty

Bx

Ws

Wp

MYwp

Yws

Xb

Xws

Xwp

Yt

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

Deriving the 4th Equation

Wperson

Wseat

Bx

TyTx

M

By

Yt Xb Xws Xwp

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

Matlab Function JTB2() -

Maximum Deflection when seat is at center position

Stainless Steel – 1” Diameter

δmax= FL3/(48EI) where I = πr4/4 Fmax=4σπ/DL

Top Bar Deflection

R1

R2

Net Forc

e

Top Traveler Bar

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

Seat Bracket Stresses

σ= My/II=1/12 * b * h3b= 6.5 inchesh=.5 inchesy=.25 inchesYt

Xwp

Tx

Wp

Seat Bracket- Back Max Yield Stress : 300.133006 psi

Seat Bracket- Bottom Max Yield Stress : 894.400000 psi

Matlab Function JTB2()

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

System interfaces (cont.)System Interfaces

Component 1 Component 2 How does it interface

Is there a critical load at this interface?

Parts associated with interface

Boat handhold Handhold Mechanism Friction force Moment Handhold Mechanism

Handhold Mechanism 80-20 Rail

80-20 fastening. Bolts connect the bearing to Handhold Mechanism No

80-20 Aluminum slot framing, bearing, hand brake.

80-20 Rail Bottom Rail Bolts to Bottom Rail No Bolts, Nuts, Rail, Bottom Rail

OR L-Bracket Fastens to L-Bracket No Bolts, Nuts, Rail, L-Bracket

Rubber Seat Pad L-Bracket Adhesive NoRubber Seat Block, L-Bracket, Bolts

Rubber Seat Pad Seat of Boat Friction force No Rubber Seat Pad

L-Bracket Bottom RailBottom rail goes through L Bracket No

L-Bracket, Bolt, Bottom Rail,Weld

L-Bracket Top Bar Flange YesL-Bracket, Top Bar, Flange/Base Mount

System interfaces (cont.)

Component 1 Component 2How does it

interface

Is there a critical load at this interface?

Parts associated with interface

Top Bar Top Bar Bearing Block Bearing NoTop Bar, Top Bar Bearing Block

Top Bar Bearing Seat Bracket Bolts NoTop Bar Bearing, Seat Bracket, Bolts

Bottom Rail Bottom Rail Bearing Block Bearing NoBottom Rail, Bottom Rail Bearing Block

Bottom Rail Bearing Seat Bracket Bolts NoBottom Rail Bearing, Seat Bracket, Bolts

Seat Bracket Lazy Susan Bolts NoSeat Bracket, Lazy Susan, Bolts

Lazy Susan Chair Bolts Maybe, Moment Lazy Susan, Chair, BoltsChair Harness Bolts No Chair, Harness, Bolt

Bottom Rail Support Post Rail-Post interface No

Bottom Rail, Support Post, 2 Quick Pins, Aluminum Square Tube

Support Post Baseplate Bolts NoSupport Post, Baseplate, Bolts

Baseplate Bottom of BoatPlate clamp, hooks in cab No

Baseplate, Boat, Plate clamp, hooks

System interfaces (cont.)

Component 1 Component 2How does it

interface

Is there a critical load at this interface?

Parts associated with interface

Seat Bracket Pad-Eye (on Seat Bracket) Bolts NoSeat Bracket, Pad-eye, screw

Pad-Eye (on Seat Bracket) Purchase System Blocks Schackle No Pad-eye, blocks, shackle

Purchase System Blocks Purchase System LineBlock - Line Interface No Block, Line

Side Bracket Pad-Eye (on Side Bracket) Bolts NoSeat Bracket, Pad-eye, screw

Pad-Eye (on Side Bracket) Purchase System Blocks Schackle No Pad-eye, blocks, shackle

Purchase System Blocks Purchase System LineBlock - Line Interface No Block, Line

Rotational Locking Mechanism Chair Undetermined No

Rotational Lock, Chair, Mystery Machine

Translation Locking Mechanism Cleats Undetermined No Translational Lock, Cleats

3-1 Purchase System Breakdown

Purchase System

Seat Bracket

Port Starboard

Lines wrap around to center position

Purchase System Representation

Bill Of MaterialsRefer to BOM + Budget doc

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

Seat Selection

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

Risk Assessment (Top 5)

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

Budget Analysis

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

High Cost Items

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

Interface (captains chair)

Currently, the brake for the Lazy Susan is undefined.

Working on several ideas

Rotational Motion Braking Mechanism

Friction Plate Force-Action Clamp Ratchet & Pawl

Curved rubber wedge into Lazy Susan turntable

Rotation Brake

Working to improve the previous team’s solution

Working hand-in-hand(hold) with group P13032 to design a standard handhold

Handhold Design

Comments & Suggestions?