Patent ID: 7533528
Filing Date: 2009-05-19
Classification: F15B

Abstract:
1. An actuator assembly comprising a body ( 2 ) in which works an actuating piston ( 7 ), a first piston ( 5 ) and at least one second piston ( 6 ), a chamber ( 26 ) containing a substantially incompressible fluid by which each of the first and second pistons ( 5 , 6 ) acts on the actuating piston ( 7 ), the arrangement being such that movement of the first piston ( 5 ) from a retracted position to a fully extended position acts via the fluid to cause the actuating piston ( 7 ) to move from a retracted position to an operational position, and with the first piston 5 remaining in its fully extended position, subsequent movement of a second piston ( 6 ) from a retracted position to an extended position acts via the fluid to cause an actuation movement of the actuating piston ( 7 ), and in which pneumatic pressure is used to extend the pistons ( 5 , 6 ).