Patent ID: 8424419

Claim:
A breakout wrench system for use with a rock drill string, the breakout wrench comprising: a frame adapted for mounting to a rock drill feed guide structure; a sub-frame rotatably connected to the frame about a drill string longitudinal axis, the sub-frame supporting a pair of opposed jaw members, each of the jaw members adapted for radial movement towards and away from one another and to releasably engage a section of a drill string; a first and second actuator, each actuator supported by the sub-frame and connected to one of the pair of jaw members, each actuator for moving the respective jaw member; a third actuator extending between the frame and the pair of jaw members, the third actuator for rotating the pair of jaw members about the drill string longitudinal axis; a flow controller connected to the first and second actuator to control the movement of each of the pair of jaw members between a first unclamped position where the pair of jaw members are retracted from the section of the drill string, and a second clamped position where the pair of jaw members are clamped on the section of the drill string and configured to breakout the section of the drill string, and a third centralizing position where the pair of jaw members are positionable between the first unclamped position and the second clamped position and are operable in a centralizing mode to centralize the drill string during a drilling operation; and wherein the third actuator includes a linking arm having a length extending a sufficient distance from the sub-frame to provide the rotation of the sub-frame and the first pair of jaw members through an angular range of approximately ninety degrees about the drill string longitudinal axis.