Pipe transfer elevator

Claim 1

A PIPE TRANSFER TOOL FOR LIFTING AND MOVING A VERTICALLY DISPOSED JOINT OF PIPE HAVING AN UPWARDLY OPEN END, INCLUDING: A VERTICALLY DISPOSED CYLINDER FREELY RECEIVED BY THE OPEN END OF SAID PIPE; A PISTON WITHIN SAID CYLINDER; A PISTON ROD CONNECTED WITH SAID PISTON AND EXTENDING VERTICALLY SLIDABLE THROUGH THE RESPECTIVE ENDS OF SAID CYLINDER, THE UPPER END PORTION OF SAID PISTON ROD HAVING A PAIR OF BORES EXTENDING DOWNWARDLY FROM ITS UPPER END PORTION AND COMMUNICATING AT THEIR LOWER ENDS WITH THE INTERIOR OF SAID CYLINDER ON OPPOSING UPPER AND LOWER END SURFACES OF SAID PISTON; A CAGE COAXIALLY CONNECTED IN DEPENDING RELATION TO THE LOWER END PORTION OF SAID CYLINDER, SAID CAGE HAVING A PLURALITY OF VERTICAL SLOTS IN ITS DEPENDING END PORTION; GRIPPING MEANS CONNECTED TO THE DEPENDING END OF SAID CAGE; A MANDREL CONNECTED TO THE DEPENDING END OF SAID PISTON ROD WITHIN SAID CAGE, SAID MANDREL HAVING TAPERED SURFACES SLIDABLY CONTACTING SAID GRIPPING MEANS AND COACTING WITH THE LATTER IN RESPONSE TO VERTICAL MOVEMENT OF THE MANDREL WITH RESPECT TO SAID CAGE FOR MOVING SAID GRIPPING MEANS INTO AND OUT OF CONTACT WITH THE INNER WALL OF SAID PIPE, SAID GRIPPING MEANS COMPRISING A PIPE GRIPPING DOG PIVOTALLY CONNECTED TO SAID CAGE WITHIN EACH SAID SLOT, SAID DOGS HAVING OPPOSING SURFACES SLIDABLE ON THE TAPERED SURFACES OF SAID MANDREL; AND MEANS CONNECTED WITH THE UPPER END OF SAID PISTON ROD FOR MOVING SAID PISTON AND LIFTING SAID PIPE, SAID LAST MENTIONED MEANS COMPRISING, PRESSURE CONDUCTING MEANS CONNECTED WITH THE UPPER END OF SAID PISTON ROD AND COMMUNICATING WITH HE PAIR OF BORES IN THE LATTER, AND AN ELEVATOR CONNECTED WITH THE UPPER END PORTION OF SAID PISTON ROD.