Automatic chucking device for drill pipe

Claim 1

A CHUCKING DEVICE FOR DRILL PIPE AND THE LIKE COMPRISING, IN COMBINATION, A CHUCK BODY HAVING A DRILL PIPE RECEIVING APERTURE AND AXIS THERETHROUGH, SAID BODY HAVING SPACED APART JAW RECEIVING AXIALLY EXTENDING PASSAGEWAYS THERETHROUGH AND IN OPEN COMMUNICATION WITH SAID DRILL PIPE RECEIVING APERTURE AND HAVING UPPER AND LOWER CAM FACES EXTENDING FROM ADJACENT THE CENTER LENGTHWISE PORTION OF THE PASSAGEWAY TO THE OUTER ENDS OF THE PASSAGEWAYS WHERE THEIR DISTANCE FROM THE AXIS THROUGH THE BODY IS GREATEST, AN UPPER AND A LOWER WEDGE SHAPED JAW IN EACH PASSAGEWAY AND EACH JAW PRESENTING A FACE FOR GRIPPING A DRILL PIPE RECEIVED IN SAID DRILL RECEIVING APERTURE OF THE BODY, SAID WEDGE SHAPED JAWS HAVING A CAM SURFACE THEREON SLIDABLY ENGAGING THE ADJACENT CAM FACE IN THE PASSAGEWAY, A TOP PRESSURE PLATE HAVING MOUNTING MEANS FOR SUSPENDING THEREFROM SAID UPPER JAWS FOR MOVEMENT ALONG THE ADJACENT CAM SURFACE AND RADIALLY WITH RESPECT TO SAID SUSPENDING MEANS, A LOWER PRESSURE PLATE HAVING MOUNTING MEANS FROM WHICH IS SUPPORTED SAID LOWER JAWS FOR MOVEMENT ALONG THE ADJACENT CAM SURFACE AND RADIALLY WITH RESPECT TO SAID SUPPORTING MEANS, A TOP PLATE SPACED ABOVE SAID TOP PRESSURE PLATE AND SECURED TO SAID CHUCK BODY, A PLURALITY OF TOP COMPRESSION SPRINGS EXTENDING AXIALLY AND DISPOSED BETWEEN SAID TOP PLATE AND SAID PRESSURE PLATE WHEREBY THE PRESSURE PLATE IS BIASED DOWNWARD ALONG WITH SAID TOP JAWS WHICH SLIDE AGAINST THEIR CAM SURFACES AND ARE URGED RADIALLY INWARD TO GRIP SAID DRILL PIPE, A BOTTOM PLATE SPACED BELOW SAID BOTTOM PRESSURE PLATE AND SECURED TO SAID CHUCK BODY, A PLURALITY OF BOTTOM COMPRESSION SPRINGS EXTENDING AXIALLY AND DISPOSED BETWEEN SAID BOTTOM PLATE AND SAID PRESSURE PLATE WHEREBY THE BOTTOM PRESSURE PLATE IS BIASED UPWARDLY ALONG WITH SAID SUPPORTED BOTTOM JAWS WHICH SLIDE AGAINST THEIR CAM SURFACES AND ARE URGED RADIALLY INWARD TO GRIP SAID DRILL PIPE, TOP AND BOTTOM JAW RETAINING MEANS HOLDING SAID JAWS IN SLIDING ENGAGEMENT WITH THEIR RESPECTIVE CAM FACES IN THEIR PASSAGEWAYS, A TOP RACE OF ANTIFRICTION THRUST BEARINGS MOUNTED AGAINST THE LOWER FACE OF SAID TOP PRESSURE PLATE AND GENERALLY IN AXIAL ALIGNMENT WITH SAID TOP COMPRESSION SPRINGS, A BOTTOM RACE OF ANTIFRICTION THRUST BEARINGS MOUNTED AGAINST THE TOP FACE OF SAID BOTTOM PRESSURE PLATE AND GENERALLY IN AXIAL ALIGNMENT WITH SAID BOTTOM COMPRESSION SPRINGS, A PLURALITY OF SPACED APART AND RECIPROCABLE POWER OPERATED MEANS DISPOSED AXIALLY BETWEEN SAID TOP AND BOTTOM ANTIFRICTION THRUST BEARING RACES WHEREBY SAID RECIPROCABLE MEANS MAY BE EXTENDED TO FORCE SAID PRESSURE PLATES AGAINST THEIR RESPECTIVE COMPRESSION SPRINGS TO MOVE SAID TOP AND BOTTOM JAWS OPPOSITE TO THEIR BIASED POSITION WHEREBY THE JAWS MOVE ALONG THEIR CAM FACES AND RADIALLY OUTWARD FROM THEIR GRIP AGAINST SAID DRILL PIPE, SAID BOTTOM PLATE HAVING MOUNTING MEANS ADAPTED TO ATTACH IT TO THE TOP OF A CROSS HEAD OF A DRILL.