In a diaphragm fluid pump which includes a diaphragm piston assembly assembled within a pump housing to form a pump chamber at one side thereof, the diaphragm piston assembly includes a diaphragm member secured in a fluid-tight manner at its outer periphery to the peripheral wall of the pump housing,...http://www.google.com.au/patents/US4541788?utm_source=gb-gplus-sharePatent US4541788 - Diaphragm fluid pump
