| 摘要 |
<p>A cylinder housing has a passageway extending in from the exterior thereof for admitting and discharging fluid to a cylinder portion. A piston in the cylinder has return movement by means of a resilient retracter, and a check valve having protected support in the housing is arranged to close off fluid discharge from the cylinder under abnormal fluid pressure return conditions such as when the ram is in use and there is a failure in the fluid supply for the piston.</p> |
