Image Number 19 for United States Patent #6726059.
An externally-mounted, quick-acting trigger assembly for firing blast aerators, air cannons, or the like. The trigger assembly is ideal for high temperature applications involving environmental factors such as excessive heat, humidity, and mechanical shock. The trigger comprises a symmetrical, ventilated housing that internally mounts a hollow piston. A plurality of vent orifices are radially disposed about the housing periphery, and normally covered by a resilient band forming a check valve. The trigger piston comprises a generally cylindrical base and an integral, generally conical bottom that is displaced into and out of contact with a mechanical valve seat. An air passageway through the piston is controlled by a deflectable spherical valve element that is captivated within the piston, for selectively blocking air passage through the piston by contacting an internal valve seat. This construction with internal air passageways facilitates trigger function. The base comprises a circumferential groove for seating an appropriate O-ring.