Abstract: An improved pawl and ratchet mechanism is disclosed wherein at least one of a plurality of pawl elements movably disposed within a housing is movable into a least one of the spaces between the teeth of a toothed track ratchet irrespective of the location of the housing with respect to the toothed track ratchet when the housing engages the toothed track ratchet. The improved pawl and ratchet mechanism may be used to contain explosive forces resulting from a pressure failure during the hydraulic testing of pipe.

Abstract: An improved vise for gripping elongated objects such as pipe is provided. The vise utilizes the rotational forces acting upon the object to be gripped to tighten the vise's grip on the object. The vise is constructed so that any force tending to rotate the object is transmitted to the vise and is translated into a gripping force to be utilized by the vise jaws of the vise. The vise is bi-directional and automatic in its operation.

Abstract: An improved method and apparatus for injecting hydraulic test fluid into a length of pipe is disclosed. Test fluid under low hydraulic pressure axially displaces a cylindrical fill valve against a retaining force. The test fluid fills the pipe through discharge ports in the side of the fill valve. The retaining force retracts the fill valve and closes the discharge ports when the pipe is full. A conduit through the fill valve then supplies high pressure hydraulic fluid for testing the internal strength of the pipe.

Abstract: An improved power tong apparatus for making and breaking connections between lengths of small diameter tubing comprising an annular cage mounted for rotation and on which are pivotally mounted a plurality of pipe-gripping rocker arms, an annular bull gear mounted for rotation in association with the annular cage and having internally positioned rollers mounted in association with the pivotally mounted pipe-gripping rocker arms, and an endless chain assembly or gear for rotating the bull gear, and a slot and pin assembly for restricting the movement of the bull gear with respect to the annular cage for causing the pipe-gripping rocker arms to be movable into an open position to release their grip on the pipe.