A bidirectional pneumatic impact wrench has a pneumatic motor and an air control
valve. The pneumatic motor has a forward air inlet and a reverse air inlet. The
air control valve directs compressed air selectively into either the forward air
inlet or the reverse air inlet to change the direction of rotation of the pneumatic
motor and includes a rotatable shaft. The shaft has an exterior surface and a spiral
forward air groove and reverse air groove that are symmetrically defined in the
exterior surface to direct the compressed air efficiently. The air control valve
is simple to fabricate and directs the compressed air efficiently into the pneumatic
motor to improve power and efficiency of the pneumatic motor.
