Abstract: An hydraulic lock alleviation device a well cementing stage tool with such a device, and related methods for their use. The device has a channel for transmitting trapped fluid which causes a hydraulic lock from the trapped area to another area. The channel is blocked by a pressure responsive member which ruptures, moves, breaks, or is punctured to permit trapped fluid to glow from the area of hydraulic lock. In one embodiment of a stage tool with such a device, a puncture apparatus can be moved to puncture the pressure responsive member. In other embodiments, a movable piston or spool is mounted in the channel for movement to permit the flow of trapped fluid.

Abstract: In a power pipe tong including doors with a latch handle and having a circular rotary with connecting ends for opening and closing and receiving pipe for make-up or break-out in which the connecting ends of the rotary are fastened together by a spring loaded plunger, the improvement in means for inserting the plunger into the connecting ends as the tong doors are closed and preventing the plunger from becoming disengaged until the doors are opened. A cam is pivotally mounted, on the tong in position for engagement with the top of the plunger for inserting the plunger into the rotary and for releasing the plunger. A connecting linkage mechanism pivotally connects between the cam and the door latch handle and is actuated by the handle for moving the cam into engagement with the plunger when the latch is closed and moves the cam out of engagement with the plunger when the latch is opened.