Powered utility cart and compliant drive wheel therefor

A lift-enabled motorized wheel assembly for a material handling cart, said assembly comprising:

• a mounting plate,
• a pair of legs extending perpendicularly from said mounting plate, said pair of legs comprising a fixed leg and a floating leg spaced laterally apart from one another, each said fixed and floating leg extending between respective captured and compliant ends, said captured ends being aligned with one another and pivotally connected about a common pivot axis to said mounting plate, said compliant ends being aligned with one another and pivotally connected about a common suspension axis,
• an axle perpendicularly intersecting said legs between said respective captured and compliant ends, said axle supported for rotation relative to said mounting plate about a generally horizontal longitudinal axis thereof,
• a drive wheel disposed on said axle in-between said legs for locked rotation with said axle about said longitudinal axis,
• a drive motor operatively coupled to said axle for co-rotating said axle and said drive wheel about said longitudinal axis,
• a lifter sub-assembly operatively disposed between said mounting plate and one of said captured and compliant ends of said fixed and floating legs, said lifter sub-assembly including an actuator moveable between extended and retracted positions, whereby said drive wheel is pressed into contact with the ground when said actuator is in the extended position and said drive wheel is lifted out of contact with the ground when said actuator is in the retracted position, said actuator having a distal end, upper and lower links pivotally attached to said distal end of said actuator, said upper link pivotally attached to said mounting plate, said lower link pivotally attached to said captured ends of said fixed and floating legs, said upper and lower links forming a generally vertical load-bearing column when said actuator is in said extended position,
• a self-aligning bearing operatively supporting said axle in said floating leg, and a clearance hole in said fixed leg for accommodating said axle to pass therethrough.