Patent ID: 8684115

Claim:
A vehicle comprising: a support structure; a wheel assembly coupled to the support structure and rotatable about a central axis in a first direction and a second direction opposite the first direction for moving the support structure forward and backward, with the wheel assembly pivotable about a pivot axis transverse to the central axis in a third direction and a fourth direction opposite the third direction for moving the support structure leftwardly and rightwardly; an electric motor coupled to the wheel assembly for rotating the wheel assembly in the first and second directions; a braking device coupled to the wheel assembly for braking the wheel assembly; a steering mechanism coupled to the wheel assembly for pivoting the wheel assembly in the third and fourth directions; a housing receiving the wheel assembly, the electric motor, the braking device, and the steering mechanism to define a self-contained unit attachable to and detachable from the support structure for providing interchangeability of the self-contained unit; and a support coupled to the housing for supporting the self-contained unit, with the housing pivotable about the pivot axis independently of the support.