| 摘要 |
A device for restraining the upward movement of a dock comprising a hydraulic cylinder having a fixed end; a piston slideably disposed in said cylinder so as to define opposed first and second chambers; a rod having one end connected to said slideable piston, extending through said first chamber and having another end adapted for connection to said dock; hydraulic reservoir containing hydraulic fluid communicating with said first chamber; valve mean s disposed between said reservoir and said first chamber, said valve means having open position permitting said hydraulic fluid to flow from said first chambe r to said reservoir and extending said rod in response to said upward movement of said dock; a closed position stopping the flow of said hydraulic fluid from said first chamber to said reservoir and restraining the upward movement of said dock.
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