US Patent 8240410 Patient support apparatus with powered wheel

A patient support apparatus has a first frame and a second frame supported above the first frame and movable relative to the first frame. A plurality of casters are coupled to the first frame. A wheel is movable relative to the first frame between a lowered position engaging the floor and a raised position spaced from the floor. A drive assembly is coupled to the wheel and is operable to drive the wheel to propel the patient support apparatus along the floor. A foot pedal is coupled to the first frame and is movable to raise and lower the wheel relative to the floor.