Wheelchair with variable ratio propulsion
US4682784A · kind A · utility
Inventor
Key dates
| Filing date | May 19, 1986 |
| Grant date | Jul 28, 1987 |
| Priority date | — |
| Expiry date | May 19, 2006 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61G5/025
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
A wheelchair hand propelled by the occupant. Levers on the sides in juxtaposition with the main wheels of the wheelchair are rotatable in the forward-backward direction about the main wheel axle as a fulcrum. A plurality of concentric ratchet rings affixed to each of the main wheels provides engagement for a discrete one of a plurality of pawls associated with each of the levers. The plurality of pawls is distributed progressively circumferentially about a shaft associated with each of the levers, and means are included to rotate the shaft to bring a discrete one of the pawls into operative relationship with a selected one of the concentric ratchet rings, thereby providing a selectable propulsion ratio. The ratchet teeth are oriented such that the pawls slide over them when the levers are pulled backward, but engage firmly when the levers are thrust forward.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.