Hand drive assembly for a wheelchair

Claim 1

In a wheelchair having a chassis, a seat, a back-rest, a pair of front, smaller diameter ground-engaging swivel wheels terminating below said seat, and a pair of back, large diameter ground-engaging driving wheels extending above said seat, said seat, back-rest and front and back wheels all carried by said chassis, said back wheels mounted on said chassis on each side of said seat for independent rotation about a horizontal axis transverse to and located below said seat in the region of said back-rest, the improvement comprising: (a) a main gear gixed to, and co-axial with, each back wheel; (b) a plate fixed to each side of said chassis; (c) a pair of hand-operated driving rings of a diameter substantially equal to the diameter of said back wheels and carried by said plate for rotation about a transverse horizontal rotation axis parallel to the rotation axis of said back wheels and upwardly and forwardly spaced from said last-named rotation axis, the rotation axis of said driving rings being spaced from the rotation axis of said back wheels by a distance which is less than the diameter of said rings and back wheels, said rings being located on the outside of the respective back wheels and overlapping the latter; (d) a driving gear fixed to, and co-axial with, each driving ring; and (e) transmission means drivingly interconnecting said main gear and said driving gear for rotation of said gears in the same direction.