Patent ID: 7556109

Claim:
An electric wheelchair suspension comprising: a supporting frame unit including a bottom frame, two posts extending respectively and upwardly from two opposite sides of a front end of said bottom frame, and two main rods connected respectively and fixedly to and extending rearwardly from said posts, said bottom frame having two aligned first pivot portions disposed respectively at two opposite sides thereof, each of said posts having a second pivot portion, each of said main rods having a third pivot portion; a linkage unit including two linkages disposed respectively on two opposite sides of said supporting frame unit, each of said linkages including an upper link connected pivotally to said third pivot portion of a corresponding one of said main rods and extending in a front-to-rear direction, said upper link having a front pivot portion disposed in front of said third pivot portion of said corresponding one of said main rods, and a rear pivot portion disposed behind said third pivot portion of said corresponding one of said main rods, a lower link connected pivotally to said second pivot portion of a corresponding one of said posts and having a front pivot portion disposed in front of said second pivot portion of said corresponding one of said posts, a front caster rod connected pivotally to said front pivot portions of said upper and lower links, a bottom link connected pivotally to a corresponding one of said first pivot portions of said bottom frame and having a rear pivot portion disposed behind said corresponding one of said first pivot portions of said bottom frame, and a rear link connected pivotally to said rear pivot portions of said upper link and said bottom link; a wheel unit disposed on an assembly of said supporting frame unit and said linkage unit; and a driving unit for driving said wheel unit.