Alternative Terrain Wheelchair Team # 1: Team ARROW Brent Fischer Mitchell Kane Eric Goyette Brennan McVeigh Chris MacKenzie Outline Current Wheelchairs Design Requirements Considered Designs Selected Design Frame & Drive Budget & Schedule 2 Current Wheelchairs [Clipart] - Wheelchair 3 Indoor Use Favored No Suspension No Gearing Soft Tissue Damage Alternative Terrain Wheelchair Braking Capabilities Gearing Suspension Repairable With Bicycle Components Ability To Reverse 4 [SolidEdge] – Full Wheelchair Considered Designs Off-Axle Crank Drive Advantages Proven concept [VarnaHandcycle.com] Fluid Hand Motion Constant Propulsion Disadvantages Smaller Moment Arm Accessibility Issues Snag And Pinch Hazard [SolidEdge] – Off-Axle Crank Design 5 Considered Designs Same Axle Wheel Drive Advantages No Learning Curve Familiar Design Disadvantages Too Many Chains Snag Hazard Unnatural Motion 6 [SolidEdge] – Same Axle Wheel Drive Considered Designs Gears with Lever Drive Advantages Ease of Reverse Many Gear Ratios Large Moment Arm Disadvantage Complicated Design Difficult to Manufacture Difficult to Repair [SolidEdge] – Gears with Lever Drive 7 Selected Design Chains with Lever Drive Advantages Easy to Repair Ergonomic Controls Low Cost Disadvantages Reverse has No Mechanical Advantage Requires Clutch [SolidEdge] – Chains with Lever Drive 8 Selected Design Features: Roll Bar Adjustable Legs Rests Bench Press Style Motion Many Standard Bike Components Geared Drive [SolidEdge] – Full Wheelchair 9 Suspended Rear Wheels [SolidEdge] – Rear Suspension 29” Treaded Tires Mountain Bike Suspension Independently Driven Wheels Outer Hand Rims Picture of Shock-absorber 10 Frame Details Collapsible, Two Folding Cross Members All Aluminum Construction 1” Square Tubing Picture of Tubing 11 [SolidEdge] – Frame Calculations - FEA Safety Factor of at Least 5 Impact Load Factor of 3 Bending Side Loading Angled Loading Design Considerations 12 [SolidEdge] – FEA Removable Seat [SolidEdge] – Removable Seat 13 Two Piece Seat Aluminum Framed Weather Resistant Locks on Frame Adjustable Foot Rests [SolidEdge] – Foot Rests 14 Removable Adjustable Independent Convenient for Amputees Safety System Waist Restraint Roll Bar Suspension Reflective Tape [SolidEdge] – Roll Bar 15 [SolidEdge] – Center of Gravity Drive System Front Castor Wheels Suspended Rear Wheels Chain Lever System Accessible Brakes, Gearing, Clutch 16 [SolidEdge] – Full Wheelchair Chain Lever System Five Gears Available Parts Clutch to Reverse Chain Tensioner 0.79 to 2.45 Gear Ratio 17 [SolidEdge] – Chain Lever System Clutch Assembly [SolidEdge] – Clutch Assembly 18 Located Centrally Non-Standard Clutch Easy to Assemble Calculations – Gear Ratios Vw ra n1 Va rw n2 ra 900m m 2.45 rw 368m m Max Ratio Vw 11 2.45 2.45 Va 11 Min Ratio Vw 11 2.45 0.79 Va 34 19 Build Report Budget SubTotal $1,877 Tax $263 Contingency (5%) $94 Total $2,234 Outside Donations $1,000 ME Departmental Donation $1,000 Total $2,000 Net -$234 20 Many off the Shelf Items Standard Metal Sizes Sponsorship Search Ongoing Schedule Construction to Start After Exam Period Aluminum Welding in Question Testing by February 1 Completion by March 1 21 Conclusions Design Requirements Met Design Essentially Completed Structural Materials Purchased Building and Testing March First 22 Special Thanks Mechanical Engineering Faculty Dr. Georgiades Pam MacDougall ME Class of 2007 23 Questions 24