Patent ID: 7819415

Claim:
An apparatus for use with a wheelchair having a rear portion with rear wheels, comprising: a base having a first and a second end; a pair of lateral wheels connected to said base at said first and second ends, respectively; said lateral wheels being disposed behind said rear wheels of said wheelchair; a means for attaching said apparatus to said rear of said wheelchair; a first lower-linkage having a first and second end, said first end of said lower-linkage being hingedly connected to said first end of said base; a second lower-linkage having a first and second end, said first end of said second lower-linkage being hingedly connected to said second end of said base; a first upper-linkage having a first and second end, said first end of said first upper-linkage being hingedly connected to said second end of said first lower-linkage; a second upper-linkage having a first and a second end, said first end of said second upper-linkage being hingedly connected to said second end of said second lower-linkage; a pair of secondary linkages transverse to said lateral wheels and hingedly connected to said base; and a first actuator adapted to provide rotational force to said pair of lateral wheels.