A low profile fluid powered actuator particularly for valves of the type in which the valve element is rotated to open and close the flow passageway through the valve body, the actuator having a novel internal porting system, means for direct attachment of the valve stem to the shaft of the actuator,...http://www.google.es/patents/US3982725?utm_source=gb-gplus-sharePatente US3982725 - Valve actuator
