Abstract: A device for applying torque to e.g. a screw-threaded pipe includes a pair of gripping jaws pivotally mounted on a cage and carrying respective followers engaging cam surfaces on the radially inner surface of a rotary drive member. The jaws have friction linings. The case is connected to a clamp on the pipe so as to prevent rotation of the cage relative to the pipe. When a rotary drive is transmitted to the drive member, its cam surfaces operate the gripping jaws to clamp them about the pipe and increases the clamping pressure until the pipe begins to rotate with the drive member. The rotary drive member is mounted on a primary support which is held against rotation about the pipe and provides the required reaction force for the rotation.

Abstract: An improved rotary drive apparatus for a drill spinner, casing tong, or the like. The apparatus has a drive wheel and idler wheels adapted to drive an endless loop member trained around a cylindrical member to be driven. Pipe engaging rollers are utilized which have freely rotating flanges. The incporation of these freely rotating flanges increases torque output, reduces vibration, reduces wear on the flanges, and reduces likelihood of damage to the cylindrical member to be driven. Reaction rollers are utilized which eliminate or reduce vibration of the cylindrical member during operation of the apparatus and which increase torque output.

Abstract: An apparatus for imparting torsion to a tubular member, including a body member, an arm member, a saddle member, and a loop means such as a chain. Torsion is imparted to the tubular member by inducing tension into the chain entrained around the tubular member so that the tubular member is brought to bear against the body member or dies in the body member. A variety of configurations of the apparatus are possible, permitting adjustment to accept different diameter tubular members and assuring maximum positive load reaction.