Systems Level Design Review

Jib Transfer Bench – P130311/11/2012

Problem Definition Customer Needs / Specifications Functional Decomposition Benchmarks First CAD Design Concept Generation Selection Criteria Matrix Preliminary Calculations Budget Estimate Project Plan

Agenda

Task is to design a mechanical solution to move a disabled jib trimmer from side to side so they can perform their crew function

Project Definition

Customer Needs & Specifications

SEE METRICS CHART

Gary & Zak◦ No leg mobility / core support◦ Desires to be fully secured

Cindy◦ Partial leg & core strength◦ Desires freedom to exit seat◦ Limited footprint available due to Richard’s chair

Height differences to consider

Individual Specific Customer Needs

Original Functional Decomposition

Revised Functional Decomposition

Benchmark

Must be able to translate AND rotate independent of each other (i.e. not fixed)

Method of Motion Across Boat

Platform

Top Travel Bars

Bottom Travel Bar

Traveler

Seat Bracket

Seat

Support Bar

Handhold mechanisms on the previous team’s captain’s chair

Handhold locking mechanisms

We plan to use something similar to secure our device to the front handholds to the boat

Handhold locking mechanisms

Brainstormed ideas for each main component of our assembly:◦ Seat◦ Method of motion (translation and rotation)◦ Method of propulsion◦ Harness◦ Locking mechanism

All must fall within our size constraints for Richard’s boat and without extending into the other team’s footprint

Concept Generation

Concept: Chair that can rotate on a pair of rails spanning the boat

Problem: With full 180° rotation, legs will smack

Method of Motion (cont.)

“Seat-Within-A-Seat” initial sketch◦ Swivel chair on rails that span the boat

One bar w/ bottom support Two bar w/o support

Method of Motion (cont.)

Telescoping arm anchored on the boat floor (platform)◦ Seat mounted on top of arm

Method of Motion (cont.)

Jib trimmers with limited core strength◦ Propel themselves linearly◦ Rotate themselves

◦ No electrical solution, 100% mechanical

Method of Propulsion

Settled on a purchase system◦ Pulley system that will allow the user to pull

themselves with a mechanical advantage

Method of Propulsion

Currently, not settled on a specific lock.◦ Fence lock, pin lock, friction plate◦ Cleating purchase system lines to lock chair

Check prices Check compatibility of what we want to do

Locking Mechanism (Chair)

Must support jib trimmer’s◦ Torso◦ Legs

Should have capability to accept and secure a user’s wheelchair cushion should they wish to use it.

Seat Concepts

Lazy Susan design

Benchmark - Team Paradise’s Seat

Swivel Stool Go-Kart Seat Racecar Seat

Seat Designs

5-point harness Secured Double-Velcro vest Lap Belt

Harness

Compiled all ideas, determined the best: “Seat-Within-A-Seat” Chair Harness or double-Velcro vest Purchase system for motion Undetermined locking mechanism

See Excel file

Selection Criteria Matrix

Component Zak & Gary Cindy

Seat Go-Kart Seat Swivel Stool

Torso Securing Mechanism 3/5 point Harness Lap Belt or Velcro

Leg Support Wheelchair Footrest none

Method of Movement SWIAS 3-bar BB&B SWIAS 3-bar BB&B

Movement Force 3-1 Purchase system 3-1 Purchase system

Locking Mechanism Friction Brake & Cleats

Friction Brake & Cleats

Selection Criteria Two separate systems based on individual

customer needs

Go-Kart Seat

Zak & Gary

Stool

Cindy

Calculations to prove the design:

Using aluminum traveler bars

Box tube deflection – 7075 Aluminum ◦ Weight sitting on ◦ Deflection: -0.0000131 inches◦ Shears at 19.9°

Box tube shear strength Looking at smaller, cheaper,

lighter materials

Preliminary Calculations

Assuming 260-lb human

Drawing

Drop platform onto floor Lock into first handhold (using similar

locking device from Gold Medal Chair) Jib trimmer sits in chair and straps in Sail away!

Sailboat Installation

Budget Estimate

Based on the Gold Medal Chair:◦ $1,658

Based on research of components that we are looking at:◦ $2,000

Preliminary Project Plan

Preliminary Project Plan (part 2)

Continue with design phase CAD Modeling Create Bill of Materials Prove Design Detailed Design Review in 3-5 weeks Order parts

Build, install, sail!

Project Plan Summary

Suggestions?