Air motor having instant torque and low air consumption

摘要

An air motor having four circumferentially spaced, radially disposed cylinders the respective radially inner ends of which slidingly engage different faces of a cube-shaped cam that is eccentrically mounted with respect to a stationary motor housing. The cam serves as a drive shaft because its eccentric mounting causes it to rotate responsive to air pressure sequentially applied to the radially inner end of pistons that are fixedly mounted in circumferentially spaced relation to a circular piston chassis positioned radially outward of the cylinders. A cylindrical bore formed in the cam is partitioned into a pressure chamber and an exhaust chamber by a shoe seal member. Four ports are formed in the cam at right angles to one another to provide fluid passageways between the pressure and exhaust chambers and slideably mounted cylinders which reciprocate with respect to their associated pistons so that rotation of the piston chassis effects valving of the motor as the cam ports sequentially and momentarily align with ports formed in the shoe seal member. The shoe seal member has three different positions and the operation of the motor depends upon which position is selected.