| 摘要 |
<p>A manually operable trigger (7), e.g. on an air-powered tool, is movable from a rest position (Fig. 1) to an active position (Fig. 2) and is urged to the rest position. A valve element (12), for controlling the flow of fluid under pressure along a passage (2), is moved to an open position (Fig. 2) in response to movement of the trigger (7) to the active position. The pressure of the fluid in the passage (2) is communicated to the trigger (7) (at least when the valve element (12) is in the open position) so as to assist in maintaining the trigger (7) in the active position. <IMAGE></p> |
