Jon Martin Schaeffer

US Patent:

6715780, Apr 6, 2004

Filed:

Oct 15, 2001

Appl. No.:

09/977424

Inventors:

Jon Eric Schaeffer - Beaverton OR 97008
Jerome Edwin Schaeffer - Beaverton OR 97006

International Classification:

B62M 114

US Classification:

280248, 2802501

Abstract:

A manual wheelchair system comprising of a pair of lever arms positioned on each side of the chair that actuate a propulsion system located entirely under the seat of the wheelchair. Both the push and pull stroke of the levers, unlimited by stroke angle, provides unidirectional forward propulsion to the rear wheels of the chair. This is accomplished through drive gears fitted with one-way clutches and idler gears intermeshing with them. A sprocket is attached to one drive gear, and connects to an internal shifting hub using a chain or belt. This hub could optionally be a manual or automatic unit, with the automatic shifting unit relying on sensory feedback from the rear drive wheel to determine the most efficient ratio of operation. The hub connects to the rear drive axle through another sprocket and chain combination and drives the rear wheel as the levers are manipulated. The rear axle has a disconnecting clutch so that the entire drive propulsion system can disengaged from the chair.