Rod break-out and make-up tool

Abstract

A rod break-out and make-up tool for screwing and unscrewing drill rods that includes a lower clamp assembly having a jaw holder that has trunnions pivotally mounted on a mounting frame, and piston cylinder combinations pivotally mounted by the jaw holder for moving jaws divergingly upwardly to a rod release position and convergingly downwardly to a rod clamping position, a high-low drive assembly having a housing that rotatably mounts a spindle that has drive lugs, a lower ring gear fixed to the spindle and driven at a high speed, low torque by a reversible hydraulic motor, an upper ring gear rotatable on the spindle and driven by a piston cylinder combination operated rack, a ratchet assembly for transmitting a driving force from the upper gear to the lower gear in one angular direction and permitting the lower gear rotating relative thereto in said one direction, legs pivotally mounted on the trunnions for supporting the drive assembly, and adjustment mechanism connected between the frame and the housing for retaining the housing in selected adjusted pivoted positions; and an upper clamp assembly having an annular piston combination for moving jaws radially inwardly to a rod clamping position, a driven member driven by said lugs and axially movable relative thereto for rotating said mechanism, and a coil spring between the upper clamp assembly and a ring joined to said lugs to permit self centering of the upper clamp assembly and support the upper clamp assembly.