Mechanism for making up and breaking out screw threaded joints of drill stem and pipe

Claim 1

A MACHINE FOR ROTATING A LENGTH OF SCREW THREADED PIPE RELATIVE TO ANOTHER LENGTH OF SCREW THREADED PIPE, WHICH MACHINE COMPRISES; A FRAME, A ONE-PIECE, CONCENTRIC, CONTINUOUS CIRCULAR, ROTATABLE DRIVE RING MOUNTED ON SAID FRAME IN JOURNALED RELATION AND HAVING AN AXIAL OPENING FORMED THERETHROUGH, RELATIVELY MOVABLE DIE HOLDERS MOUNTED WHOLLY WITHIN SAID DRIVE RING, PIPE ENGAGING DIES MOUNTED ON EACH SAID DIE HOLDER AND EACH HAVING THE RESPECTIVE PIPE ENGAGING DIES THEREOF MOVABLE RADIALLY INWARD TOWARD THE AXIS OF SAID DRIVE RING AND ROTATABLE THEREWITH, CAM MEANS WITHIN SAID AXIAL OPENING, CAM ENGAGING FACES ON EACH DIE HOLDER TO COMPLEMENTALLY ENGAGE SAID RESPECTIVE CAM FACES WITHIN SAID AXIAL OPENING OF SAID RING TO MOVE SAID DIE HOLDERS THEREIN TO ENGAGE A LENGTH OF PIPE UPON LIMITED ROTATION OF SAID DRIVE RING RELATIVE TO SAID DIE HOLDERS, PIPE HOLDING MEANS MOUNTED ON AND ATTACHED TO SAID FRAME BELOW SAID DRIVE RING AND BEING ENGAGEABLE WITH THE OTHER OF SAID LENGTHS OF PIPE TO SELECTIVELY HOLD SAID LAST MENTIONED LENGTH OF PIPE AGAINST RELATIVE ROTARY MOVEMENT WHEN SAID LAST MENTIONED PIPE HOLDING MEANS IS IN ONE POSITION, A FLUID ACTUATED MOTOR MOUNTED ON SAID FRAME TO IMPART ROTARY MOVEMENT TO SAID DRIVE RING, A LOW SPEED, FLUID ACTUATED, TORQUE LIMITING CLUTCH MOUNTED ON SAID FRAME, A HIGH SPEED, FLUID ACTUATED CLUTCH MOUNTED ON SAID FRAME, SAID CLUTCHES BEING SELECTIVELY CONNECTABLE IN DRIVING RELATION WITH SAID RING, SAID FLUID MOTOR BEING CONNECTED IN DRIVING RELATION WITH SAID CLUTCHES, AND VALVE MEANS FOR SELECTIVELY DIRECTING FLUID UNDER PRESSURE TO SAID CLUTCHES.