Flareless tube coupling

Claim 1

A FLARELESS TUBE COUPLING COMPRISING FIRST AND SECOND THREADEDLY ENGAGED COUPLING MEMBERS DEFINING A TUBE-END RECEIVING CAVITY THEREBETWEEN INCLUDING AN ANNULAR SPACE AROUND THE TUBE WITH CORRESPONDING FIRST AND SECOND TAPERED ANNULAR END WALLS THAT MOVE AXIALLY TOWARD EACH OTHER WHEN SAID MEMBERS ARE SCREWED TOGETHER; AND A TUBULAR FERRULE IN SUCH SPACE, SAID FERRULE BEING COUNTERBORED AT THE END ADJACENT SAID FIRST END WALL TO PROVIDE A LEADING EDGE THAT HAS A RADIAL CLEARANCE WITH THE TUBE AND BEING FORMED WITH A GENERALLY CYLINDRICAL PORTION OF SUBSTANTIAL LENGTH AND SUBSTANTIALLY UNIFORM RADIAL THICKNESS WHICH IS OF A DIAMETER GREATER THAN THE AXIALLY ADJOINING PART OF THE INTERMEDIATE PORTION OF SAID FERRULE, SAID INTERMEDIATE PORTION HAVING A TAPER OF INCREASING RADIAL THICKNESS TERMINATING IN A PERIPHERAL GROOVE, AND A HEAD OF LARGER DIAMETER THAN SAID CYLINDRICAL PORTION AND SAID GROOVE EXTENDING FROM SAID GROOVE TO THE END OF SAID FERRULE, SAID HEAD ADAPTED TO BE INITIALLY CONTACTED BY SAID SECOND END WALL ONLY ALONG THE PERIPHERY OF ITS RADIALLY OUTER AXIAL END EDGE, WHEREBY, WHEN SAID MEMBERS ARE SCREWED TOGETHER, SAID FIRST END WALL CONTRACTS END OF SAID CYLINDRICAL PORTION FORCING SAID LEADING EDGE INTO GRIPPING ENGAGEMENT WITH SAID TUBE AND SAID SECOND END WALL SWINGS SAID HEAD ABOUT SAID GROOVE TO RADIALLY CONTRACT THE HEAD END OF THE FERRULE AGAINST SAID TUBE, SAID SECOND END WALL COMING INTO FULL CONTACT WITH THE LATERAL END OF SAID HEAD.