Drill steel centralizer for extension drill steels

Claim 1

IN DRILL CENTRALIZER APPARATUS OF THE CHARACTER DESCRIBED FOR MOUNTING ON THE FEED SHELL OF A ROCK DRILL FOR ACCOMMODATING THE COUPLING SLEEVES OF A STRING OF EXTENSION DRILL RODS ACTUATED BY SAID ROCK DRILL AND CONNECTED BY COUPLING SLEEVES LARGER THAN SAID RODS FOR THE COUPLING AND UNCOUPLING THEREOF, AND HAVING A SUPPORT MOUNTED ON THE FEED SHELL WITH JAWS MOVABLY MOUNTED BETWEEN A CLOSED AND A SEPARATED POSITION ON SAID SUPPORT AND FORMING IN SAID CLOSED POSITION THEREOF AN AXIALLY DIVIDED SOCKET IN ALIGNMENT WITH SAID STRING, SAID SOCKET HAVING AN OPENING SUFFICIENT TO RECEIVE SAID SLEEVES THEREIN UPON AXIAL MOVEMENT OF SAID STRING IN ONE LONGITUDINAL DIRECTION THEREOF, THE COMBINATION WHICH COMPRISES MEANS FOR BIASING SAID JAWS TO SAID CLOSED POSITION THEREOF, RESILIENT MEANS ON SAID SUPPORT AND CONNECTED TO SAID JAWS AND RESPONSIVE TO SAID SOCKET THEREON FOR RECEIVING A SLEEVE IN SAID CLOSED POSITION OF SAID JAWS FOR CAUSING SAID SOCKET TO GRIP SAID SLEEVE FRICTIONALLY AND RESIST ROTATION DURING SAID COUPLING AND UNCOUPLING THEREOF, AXIAL ABUTMENT MEANS ON SAID JAWS ADJACENT SAID SOCKET, SAID ABUTMENT MEANS COOPERATING IN SAID CLOSED POSITION WITH THE INNER END OF THE SLEEVE RECEIVED IN SAID SOCKET FOR POSITIVELY PREVENTING SAID SLEEVE FROM PASSING SAID JAWS AXIALLY IN SAID ONE DIRECTION, GUIDE SURFACES ON SAID JAWS FORMING IN SAID CLOSED POSITION THEREOF A GUIDING OPENING FOR SAID DRILL RODS LARGER THAN SAID RODS BUT SUBSTANTIALLY SMALLER THAN SAID SLEEVES, AND MEANS CONNECTED TO SAID JAWS FOR THE MOVEMENT THEREOF TO SAID SEPARATED POSITION FOR PERMITTING SAID SLEEVES TO FREELY PASS SAID JAWS DURING AXIAL MOVEMENT OF SAID STRING IN EITHER DIRECTION.