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

Abstract: 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 means disposed between said reservoir and said first chamber, said valve means having open position permitting said hydraulic fluid to flow from said first chamber 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.

Abstract: Apparatus for equalizing pressure between two conduits including means for sensing pressure in said conduits; valve means communicating between said conduits, said valve means adapted to open so as to equalize pressure between said conduits.