Patent ID: 6572076
Filing Date: 2003-06-03
Classification: F16H,F16K

Abstract:
A valve actuator (1) comprising:a housing (2); an actuating member (4) partly contained within the housing and movable relative to the housing; drive means (8,9) arranged to drive the actuating member (4) between first and second positions to reconfigure a valve (10) between first and second states; energisable resilient means (22) within the housing; locking means (25,26,27) for locking the resilient means in an energised state, the locking means permitting the drive means to drive the actuating member from either of its positions to its other position without substantially energising or de-energising the resilient means when the resilient means is locked by the locking means; release means (28,29) for releasing the resilient means from the locking means, to cause the actuating member to be moved under the influence of de-energisation of the resilient means to one of its positions and thereby reconfigure the valve from one to the other of its states; and load transfer means (17) displacably mounted within the housing (2) and being biased relative to the housing by the resilient means (22), characterised in that the locking means includes the load transfer means (17) which is slidably mounted about the actuating member (4); and the resilient means (22) is arranged to be energised by the drive means (8,9) operatively engaging the actuating member (4) and moving the load transfer means (17) relative to the housing (2) and the actuating member (4) to a position in which the locking means (25, 26, 27) can lock the resilient means in an energised state.