Anti-Tip Bar for manual wheelchair

1. Anti-Tip Barfor manual wheelchair Nick Burjek Andrew Dawson Austin Dirks Katie Gallup Harrison Lamons

2. Problem Statement • Manual wheelchairs are typically equipped with anti-tip bars that prevent the wheelchair from tipping over backwards and injuring the user. • Decrease mobility of user • Higher risk of tipping

3. Background • Target audience is new lifetime wheelchair users • High demand for freedom and mobility • Chairs need higher performance characteristics • Wheelchair users will nearly always remove anti-tip bars found on back of wheelchair • Found to be obtrusive • Gets in the way of wheelies, turning, uneven terrain changes, etc. Anti-Tip Mechanism Anti-Tip Mechanism

4. Project Goals and Requirements • Develop a mechanical system that engages to prevent accidental tipping while preserving the mobility of the active user. • Inexpensive and lightweight • Maintain upright footprint • Be able to fold to fit into front seat of a car • Allow user to rest in a reclined position • Not inhibit any desired motion • No added effort from user

5. Methods • Use a hinge based support system with spring • Serves 2 functions • Provides resistance to user while achieving their balancing point • Acts as a stop to prevent user from tipping backwards Current example of anti-tip system

6. Design Stopping Wedge Spring Spring Uniball wheel

7. Method

8. Current Status • Completed building of one prototype • Performed feasibility testing • Redesign of first prototype • Wedge incorporation • Uniball wheel • Smaller Hinge • Spring centered • Improved general construction of prototype

9. Current Demonstration

10. Results • Feasibility of new prototype tested in demonstration • Shown to hold up weight of normal human • Able to rotate during wheelie • Adds resistance to user while reaching balance point • More aesthetically pleasing

11. Future Work • Test new prototype on different terrain, curbs, wheelies, normal everyday functions • Transfer current prototype design to Pro-E • Create a sturdy, finalized, machined prototype • Time and resource permitting, work on a smart system incorporating solenoid angle sensors to actively engage when user tips