Patent ID: 8794491

Claim:
An adhesive dispensing module, comprising: a housing including a liquid inlet for receiving an adhesive, a liquid outlet for discharging the adhesive, and a liquid passage communicating between the liquid inlet and the liquid outlet, the liquid passage including a valve seat; a dispenser valve member mounted for movement in the housing relative to the valve seat between open and closed positions, the dispenser valve member including a piston; and a pneumatic actuator configured to actuate reciprocating movement of the piston between the open and closed positions, the pneumatic actuator comprising: an air supply inlet, an air exhaust outlet, and a piston chamber each positioned within the housing, the piston chamber receiving the piston such that the piston divides the piston chamber into first and second piston chamber portions; and a valve element located within the housing and including a plurality of first inlet passages located at different positions around the piston chamber and a plurality of first exhaust passages located at different positions around the piston chamber, the valve element being moveable from a first position in which the plurality of first inlet passages communicate with the air supply inlet and the first piston chamber portion to deliver pressurized air into the first piston chamber portion to move the piston, and a second position in which the plurality of first exhaust passages communicate with the first piston chamber portion and the air exhaust outlet to exhaust pressurized air from the first piston chamber portion.