| 摘要 |
<p>A pneumatic hydraulic booster pump (5), an overload protecting valve (10) and a pressure compensating valve (14) are connected in parallel with an overload absorbing hydraulic chamber (3) within a slide (2) of a mechanical press (1). The pressure compensating valve (14) has a restricting passage (60) and a relief valve (61) connected to each other in series. The relief valve (61) comprises a valve closing piston (71) which pushes a relief member (72) in a direction for valve closing, a valve closing actuation chamber (73) which communicates with a compressed air supply passage (30) of the booster pump (5), and a compression spring (74) which urges the relief member (72) in the direction for valve closing. <IMAGE></p> |
