Abstract: A fluid actuated engine valve assembly comprising a fluid actuator (10) including a chamber (14) in which a piston assembly (17) reciprocates. The piston assembly (17) includes a pair of spaced pistons (18,19) which divide the chamber (12) into three sections (20 21,22) and a passageway (29) which supports a slide valve member (30). Movement of the slide valve member (30) in one direction causes fluid to be directed to the chamber section (20) to cause movement of the piston assembly (14) in one direction. Movement of the valve member (30) in the opposite direction vents the chamber (20) and permits spring (34) and/or spring (42) to move the piston assembly 17 in the opposite direction.

Abstract: A fluid actuator (10) including a chamber (14) in which a piston assembly (17) reciprocates. The piston assembly (17) includes a pair of spaced pistons (18, 19) which divide the chamber (14) into three sections (20, 21, 22) and a passageway (29) which supports a valve member (30). Reciprocating movement of the slide valve member (30) causes fluid to be directed to the chamber sections (20) and (22) and thereby corresponding reciprocating movement of the piston assembly (17). The actuator (10) may be applied to the control of any device such as valves of internal combustion engines, fuel injectors or comprise actuating means for the piston of an internal combustion engine.