Apparatus for supporting and positioning a workpiece

Claim 1

IN A PIPE THREADING MACHINE HAVING A FRAME, THE INVENTION COMPRISING A ROTATABLE SLEEVE MOUNTED ON SAID FRAME AND ADAPTED TO BE CONNECTED TO A SOURCE OF POWER FOR ROTATING SAME, SAID SLEEVE BEING ADAPTED TO RECEIVE A LENGTH OF PIPE THEREIN, INCLUDING AN END OF THE LENGTH WHICH IS TO BE THREADED, SAID END OF THE LENGTH EXTENDING A SHORT DISTANCE OUT THROUGH AN END OF SAID SLEEVE, A FIRST CHUCK CARRIED BY SAID SLEEVE AND ROTATABLE THEREWITH, SAID FIRST CHUCK BEING LOCATED ON SAID SLEEVE SUBSTANTIALLY ADJACENT THE END THEREOF OPPOSITE THE END THROUGH WHICH THE END OF THE PIPE EXTENDS, SAID FIRST CHUCK HAVING MOVABLE JAWS WITH BITING EDGES CONNECTED TO MEANS FOR MOVING THEM INTO AND OUT OF ENGAGEMENT WITH THE PERIPHERY OF THE PIPE, A SECOND CHUCK CARRIED BY THE SLEEVE AND ROTATABLE THEREWITH, SAID SECOND CHUCK BEING POSITIONED SUBSTANTIALLY ADJACENT THE END OF THE SLEEVE THROUGH WHICH THE END OF THE PIPE EXTENDS AND HAVING JAWS ADAPTED TO ENGAGE AND SHAPED TO FIT AROUND AT LEAST A PART OF THE PERIPHERY OF SAID PIPE AND CONNECTED TO MEANS FOR MOVING THEM INTO AND OUT OF ENGAGEMENT WITH THE PIPE, LOCK MEANS IN OPERATIVE CONNECTION WITH THE JAWS OF SAID SECOND CHUCK, SAID LOCK MEANS BEING A MOVABLE PISTON DISPOSED IN A FLUID FILLED CYLINDER, SAID PISTON BEING IN OPERATIVE CONNECTION WITH SAID JAWS AND DIVIDING SAID CYLINDER INTO TWO CHAMBERS, A CONDUIT INTERCONNECTING SAID TWO CHAMBERS FOR FLOW OF FLUID THEREBETWEEN IN RESPONSE TO MOVEMENT OF SAID PISTON, VALVE MEANS CONNECTED INTO SAID CONDUIT SO THAT CLOSING SAID VALVE MEANS PREVENTS FLOW OF FLUID BETWEEN SAID CHAMBERS AND MOVEMENT OF SAID PISTON WHEREBY SAID LOCK MEANS ACTING THROUGH SAID JAWS RESISTS RADIAL MOVEMENT OF SAID PIPE WITHOUT APPLICATION OF PRESSURE THERETO AND SO THAT OPENING SAID VALVE MEANS DISCONNECTS SAID LOCK MEANS.