| 摘要 |
<p>In an apparatus for use in operating a mechanism such as a valve, a single resilient means (29) is utilised for biassing, for example, a valve to both the open and closed positions dependent upon which position is selected. First and second escapement means (31, 32) are cooperable with the housing (24) and actuator (26), and confine the resilient means (29) in compression. The first escapement means (31) is selectively operable to limit movement of one end of the resilient means (29) relative to the housing (24) or actuator (26), and the second escapement means (32) is similarly operable to limit relative movement of the other end of the resilient means (29). Said first and second escapement means (31, 32) alternatively secure opposite ends of the resilient means (29) to the housing (24) and actuator (26) in response to movement of the actuator (26), whereby the resilient means (29) alternately urges the actuator (26) in opposite directions, providing the desired biassing once a change in the position has been selected.</p> |
