Patent ID: 8567798

Claim:
A base for a mobile cart, comprising: a frame; a plurality of wheel members mounted to the frame, each wheel member comprising a wheel, where at least two of the wheel members swivel relative to the frame, and at least one of the wheel members is fixed such that it does not swivel relative to the frame; a traction wheel housing assembly coupled to the frame, the traction wheel housing assembly comprising: a non-swiveling wheel assembly comprising the non-swiveling wheel, a first wheel bracket, and a second wheel bracket, the non-swiveling wheel member rotatably coupled between the first wheel bracket and the second wheel bracket at an axis of rotation, each of the first wheel bracket and the second wheel bracket defining a corresponding first engagement slot and a second engagement slot; and a traction wheel housing, comprising: a first assembly plate and a second assembly plate, the non-swiveling wheel assembly pivotably coupled between the first assembly plate and the second assembly plate at a first end of the traction wheel housing, and a bushing coupled between the first assembly plate and the second assembly plate at a second end of the traction wheel housing, the second end opposing the first end, the bushing at least partially disposed within the first engagement slot and the second engagement slot defined by the corresponding first wheel bracket and second wheel bracket, the first engagement slot and the second engagement slot configured to guide the bushing and limit the motion of the non-swiveling wheel assembly as the non-swiveling wheel assembly pivots between a first position and a second position relative to the traction wheel housing; where the traction wheel housing comprises a wheel-positioning assembly coupled to the non-swiveling wheel assembly; and where the wheel-positioning assembly is adapted to move the non-swiveling wheel assembly between the first position and the second position relative to the traction wheel housing and relative to the frame.