Abstract: An air motor comprising a cylinder, a piston, and a valve mechanism for controlling the supply and exhaust of air to and from opposite ends of the cylinder, the valve mechanism comprising a D-valve and an actuator for the D-valve operable by the pressure air for driving the piston, movement of the actuator being controlled by valves at opposite ends of the cylinder for exhausting air from opposite ends of the actuator, these exhaust valves being operated by the piston, and the motor having means operable by the piston at each end of its stroke for restricting the exit of air from the cylinder to cushion the piston and prevent it from striking the ends of the cylinder.