Instructions on Completing Mock-Up of Spring-Loaded Design for Lift/Lower of Center-Mounted Footrests on Power Wheel Chairs

Center-mounted footrests lift to be stowed beneath the seat well, and lower to be deployed. A mechanism for independent operation of footrest stowage and deployment is not included in market power wheel chairs, and PWC users have expressed the need for such a mechanism. My group research at Georgia Tech has aimed to design a solution that permits wheelchair users to independently lift and lower a center-mounted footplate during transferring processes.

The mock-up is constructed to showcase the mechanism by which the track slide design works to lift and lower the power wheelchair center-mounted footrest.

link to youtube video demonstrating use, and uses of several other designs:
http://www.youtube.com/watch?v=5ks2oms2GBs

Step 1 Materials

MATERIALS NEEDED FOR CONSTRUCTION

Torsion spring
o Preferred with housing
o Spring force sufficient to move 5lb, 10 in. long mass
o Part used: Metal spring door closer (home depot)
"Features a non-handed design with adjustable closing tension. Easily mounts to the surface and can operate up to a 150 lb. load. (MFG Model # : KC10HD, MFG Part # : KC10HD)" - Homedepot.com

Spring Plunger
o part used: brass pull ring hand (McMaster Carr, part # 8482A421)
"retractable plunger, nonlck nose, 3/8 in- 16, w/o lock, 2.0 4.0 # end force" - Homedepot.com

Cable system
o Length of cables allows stretch from spring plunger to hand operated lock release
o Hand-operated manual pull mechanism to lift spring plunger
o Tension such that the pin is moved with a deliberate hand motion
o Part used: Bike Brake ; Only handle and cable used

Two 80/20 aluminum bar segments
o 2 x 1 x (1 in. * height of seat well)
o 2 x 1 x 1 in.

80/20 fasteners

hook - eye screw

small bracket

various setscrews