Coupled pile driving mandrel

Claim 1

A JOINTED MANDREL FOR SPIRALLY CORRUGATED CASINGS COMPRISING IN COMBINATION A PAIR OF ALIGNED CYLINDRICAL TUBES EACH HAVING A FLUID PRESSURE CHAMBER INCLUDING A CIRCULAR TUBULAR PORTION, EXPANSIBLE MEANS EXTENDING THROUGH OPENINGS IN EACH TUBE RADIALLY EXPRESSABLE IN RESPONSE TO PRESSURE IN THE CHAMBER FOR FITTING INTO THE CORRUGATIONS OF A CASING, MEANS FOR CONDUCTING PRESSURE FLUID BETWEEN THE CHAMBERS TO EXPRESS THE EXPANSIBLE MEANS OF ONE TUBE WHEN THE EXPANSIBLE MEANS OF THE OTHER TUBE IS EXPRESSED, SAID CONDUCTING MEANS INCLUDING A CONDUIT EXTENDING BETWEEN SAID CIRCULAR PORTIONS OF SAID FLUID PRESSURE CHAMBERS AND HAVING OPPOSITE CIRCULAR ENDS SLIDABLE IN SAID TUBULAR PORTIONS TO PERMIT RELATIVE AXIAL MOVEMENT OF THE TUBES IN BEING COUPLED AND UNCOUPLED, SEALING MEANS BETWEEN EACH END FO THE CONDUIT AND THE SURROUNDING TUBULAR PORTION, A HOLLOW COUPLING SURROUNDING THE CONDUIT, THE COUPLING INCLUDING A MALE CYLINDER ENGAGING IN ONE END OF ONE TUBE AND INCLUDING A SECOND MALE CYLINDER JOINED TO THE FIRST AND ENGAGING IN THE ADJACENT END OF THE OTHER TUBE, THE COUPLING ALSO INCLUDING AN ABUTMENT FOR COMPRESSIVE FORCES BETWEEN THE ENDS OF THE TUBES, EACH OF THE MALE CYLINDERS HAVING A FIRST GROOVE EXTENDING IN THE DIRECTIONOF ITS PERIPHERY, EACH TUBE HAVING A MATING SECOND GROOVE EXTENDING CIRCUMFERENTIALLY ALONG ITS INNER SURFACE, MEANS FOR TRANSMITTING TENSION FORCE BETWEEN THE TUBES INCLUDING BALLS BETWEEN THE GROOVES PREVENTING SEPARATION OF THE TUBES, EACH TUBE HAVING AN OPENING THROUGH ITS WALL INTO THE SECOND GROOVE THROUGH WHICH THE BALLS CAN BE INSERTED INTO THE PAIR OF GROOVES AND REMOVED THEREFROM, AND MEANS FOR ALIGNING THE EXPANSIBLE MEANS OF ONE TUBE WITH THE EXPANSIBLE MEANS OF THE OTHE RTUBE INCLUDING AXIALLY SLIDABLE AND NON-ROTATABLE ENGAGING MEANS ON SAID COUPLING AND EACH OF SAID TUBES.