Abstract: A jaw assembly is provided for a power tong or back-up tong to make up and break out a pipe section. The jaw assembly includes a jaw element for transferring torque from the tong to the pipe section, and a means for moving the jaw element into and out of gripping engagement with the pipe section. At least one die holder is rotatably mounted to the jaw element and is adapted to freely twist about a first axis oriented generally parallel to a longitudinal axis of the pipe section when engaged with said jaw element. The rotation of the die holder about the first axis allows the die holder to align itself with the pipe section upon engagement therewith and to provide an independent camming action against the pipe section to at least radially maintain the die holder's grip on the pipe section and avoid slippage therebetween when transferring torque. The jaw assembly may therefore be used on a range of pipe sizes without having to change the jaw.

Abstract: A back-up tong is provided for use with a power tong to make up and break out longitudinally adjoining pipe sections. A torque arm engages the back-up tong and power tong to transfer torque therebetween, and a load cell is provided to measure the torque. The rear of the back-up tong has a fin element is rotatably mounted thereto. The fin element and torque arm are driven together upon initiating make up or break out operations to trap the load cell therebetween. The rotatable fin element substantially maintains alignment with the load cell and torque arm during make up for more reliable torque measurements. The fin element may alternately be mounted to the power tong.

Abstract: An open-mouth power tong of the type used to make up and break out threaded connections between tubular members includes an improved mechanism for properly aligning the pipe when it is gripped by the tong so that the pipe may be rotated evenly about its axis.

Abstract: An open mouth power tong is described having a novel arrangement for preventing relative rotation between the tong cage plates and rotary gear in situations where the pipe is not gripped at the completion of the camming action and in situations where the tong parts must be aligned for placing the tong on a pipe or removing it from a pipe. The assembly includes a pair of arcuate grooves formed in the upper surface of the rotary gear--one for use in make up operations and the other for use in break out operations. A rigid pin member is provided for extending through one of a pair of apertures formed in the upper cage plate. When the camming action is complete, i.e., when the cam followers have reached the extremities of the cam surfaces, the rigid pin member engages the remote boundary of the respective arcuate groove so as to join the cage plates and rotary gear and cause them to rotate together. When it is desired to align the tong parts for pipe access, the pin engages the near boundary of the groove.