Patent ID: 7520519

Claim:
A wheelchair, comprising: a foldable frame for supporting a seat; a first and a second wheel attached to said frame; said first wheel including a first transmission and said second wheel including a second transmission; a first manually driven drive lever for driving said first wheel, said first drive lever including a first pawl for engaging a first ratchet surface on said first transmission; a second manually driven drive lever for driving said second wheel, said second drive lever having a second pawl for engaging a second ratchet surface on said second transmission; said first and said second ratchet surface each having a substantially radial leading and trailing edge for engaging said first pawl and second pawl respectively; said second pawl of said second drive lever being reversed in direction of ratchet surface engagement as contrasted to said first pawl of said first drive lever; and wherein said first transmission and said second transmission each have a sun gear and a planetary gear arrangement.