Apparatus for tubular drill string making or breaking

Abstract

An apparatus for tubular drill string making or breaking including top wrench assembly, bottom wrench assembly, support structure, and control device. The top wrench assembly includes two top wrench bracket assemblies, top pair of movable gripping arms, top arm actuator, and top wrench camming actuator. The arm actuator allows the gripping arms to be closed or opened around the outer circumference of the pipe section, allowing top wrench assembly to engage differing casing sizes. The bottom wrench assembly includes two bottom wrench bracket assemblies, bottom pair of movable gripping arms, and bottom arm actuator. The bottom arm actuator allows the gripping arms to be closed or opened. The top wrench assembly is directly mounted on top of the bottom wrench assembly to allow relative rotation of the drill pipe section therewith. Once a pair of rollers is rotated by a hydraulic motor in the top wrench, or a pair of stationary rollers in the bottom wrench are both engaging with outer surface of the drilling string, the rollers automatically and naturally centralize or align a die insert to the most desirable central position. At this point the maximum number of die insert teeth evenly bite into the outer surface of the drill string.

Dependencies are inferred from the claim text.