Power tongs and the back-ups are disclosed which have improved means for gripping pipe and tubular members. Torque is applied and held with minimum damage to the pipe or tubular member. A plurality of gripping assemblies, each consisting of a pivoted jaw having a friction surface, are mounted on a drag ring. Rotational resistance is selectively applied to the drag ring to cause the jaws to make contact with or be released from the pipe prior to any torque being applied to the pipe. Various modifications of the gripping assemblies are disclosed to provide better gripping contact with the pipe.

An open-head power tong having an access door is provided with an improved door-interlock mechanism which ensures that the door is closed before the power tong can be operated. The interlock mechanism includes a pneumatically actuated contact valve connected to a pneumatically piloted hydraulic diverter valve which is operably associated with the hydraulic motor that drives the tong. The contact valve is so positioned on the tong such that the door when moved to its closed position engages the contact valve causing the flow of pneumatic pressure to the diverter valve to position the same so as to permit hydraulic fluid to flow to the hydraulic motor for operation of the power tong. When the door is in its open position, out of engagement with the contact valve, the contact valve relieves the pressure on the diverter valve thus positioning the diverter valve to divert the flow of hydraulic fluid around the hydraulic motor whereby the operation of the power tong is stopped.

A gripping and rotating tong device for handling drill rods, drill bits and other corresponding, at least partially rod-like pieces. The tong device comprises a housing fastened to a movable transfer device, the housing having an axial hole and a radial aperture for taking the piece to be handled from outside the housing to inside it, and in the housing it has grippers which grip the workpiece introduced into the housing, and parts for rotating the grippers. The grippers include at least two locking ring gears which rest in bearings rotatably in relation to the housing, at least one of them having cogging on the outer periphery and each having a notch extending to the center, along which notch the workpiece can pass to the center of the ring gears and away from them. The rotating of the ring gears is effected by at least one gear, the workpiece centered with the ring gears rotating together with them. The centering and/or releasing of the workpiece is effected by a limited turning of one ring gear in relation to the other ring gear, produced by the starting, ending or changing of direction of the rotation.

An open-head power tong having a bifurcated frame defining a central opening and a side opening, a rotatably supported ring having a side opening and which carries releasable pipe engaging jaws that move into and out of the central opening, and a reversible hydraulic motor for driving the ring and the jaws therewith to respectively engage and rotate a pipe in a clockwise and a counterclockwise direction during respective make-up and break-out of a drill string, is provided with a pneumatically operated indexing mechanism which automatically aligns the side openings of the frame and the ring after the termination of a make-up or break-out operation such that a drill pipe, located within the central opening, is permitted to be passed laterally therethrough so as to allow the removal of the tong from the drill string.

A power energized mechanism for connecting and disconnecting pipe connections and the like comprising a housing structure having interconnected therewith a rotatable drive gear that is rotated by means of a suitable motor. A pair of spaced external ring gear elements are interconnected with the rotary drive gear with the external gear teeth thereof disposed in interengaging relation with opposed pinion gears provided on a plurality of cam elements that are positioned in spaced relation about the ring gears. Each of the cam elements incorporates an intermediate cam section having defined thereon a pair of cam surfaces that are adapted respectively to engage pipe that is positioned within the receptacle defined by the cooperating gear and cam mechanisms. To minimize deformation of the pipe during pipe rotating operations, the cam surfaces that engage the pipe define uniform motion curve cams that have the effect of self-tightening to ensure restriction of the magnitude of frictional engagement with the pipe to only that necessary for accomplishing rotation of the pipe.