Vehicle with vertically movable power wheels

Claim 1

A vehicle for travel over a roadway, said vehicle comprising: a chassis, support wheels rotatably mounted on said chassis for supporting said vehicle on the roadway, at least a pair of power wheels adjustably mounted from said chassis for substantially vertical movement relative to said chassis to allow variable frictional engagement with the roadway, a motor means mounted on said chassis, coupling means between said motor means and said power wheel for transmitting power from said motor means to said power wheels, and means for variably forcing said power wheels into frictional engagement with the roadway to provide the needed traction to move said vehicle while said vehicle is substantially supported by said support wheels thereby reducing the power needed to move said vehicle to a minimum; said coupling means comprising a universal joint attached to the output shaft of said motor means for allowing relative movement between said motor means and said pair of power wheels, a drive shaft attached to said universal joint opposite the output shaft of said motor means, differential means attached to said drive shaft opposite said universal joint, and axle means attached to said differential means and to said pair of power wheels; said means for variably forcing said pair of power wheels into frictional engagement with the roadway comprising arm means pivotally attached to said chassis and to said axle means, means for applying a force against said arm means, and means for activating said means for applying a force against said arm means; said means for applying a force against said arm means comprising a fluid piston means.