Tube coupling

Claim 1

A TUBE COUPLING COMPRISING INTERENGAGED MALE AND FEMALE TUBULAR COUPLING PARTS, OF WHICH SAID MALE PART HAS A BORE OF RECEIPT FOR A TUBE THEREIN FOR FUSE-BONDING TOGETHER OF SAID MALE PART AND THE TUBE; SAID BORE HAVING A TAPERED TUBE-END CENTERING SEAT, AND A CIRCUMFERENTIAL SERIES OF RADIAL INWARD PROJECTION MEANS AXIALLY SPACED A SUBSTANTIAL DISTANCE FROM SUCH TUBE-END CENTERING SEAT FOR NON-BITING ENGAGEMENT WITH THE OUTER SURFACE OF THE TUBE TO MAINTAIN A UNIFORM RADIAL CLEARANCE BETWEEN THE TUBE AND THE BORE FOR FLOW OF BONDING MATERIAL FROM THE END OF THE TUBE AT LEAST TO SAID PROJECTIONS; AND MEANS FOR CLAMPING SAID PARTS TOGETHER IN FLUIDTIGHT RELATION; SAID MALE PART COMPRISING A BODY PORTION FROM THE AXIALLY INNER END OF WHICH PROJECTS A RELATIVELY THIN AXIAL LIP OF AXIAL LENGTH ABOUT FOUR TIMES ITS MAXIMUM THICKNESS AT THE JUNCTION WITH SAID MALE PART, OF SUBSTANTIALLY UNIFORM INSIDE DIAMETER, AND OF PROGRESSIVELY DECREASING RADIAL THICKNESS TOWARD ITS FREE END WITH ITS OUTER FACE BEING A PORTION OF A TORUS, SAID AXIAL LIP DEFINING AN AXIALLY INWARDLY EXTENDING HEAT SENSITIVE SEALING MEANS OF A CROSS-SECTIONAL THICKNESS CONSIDERABLY LESS THAN THE GIVEN CROSS-SECTIONAL THICKNESS OF SAID BODY PORTION, SAID BODY PORTION BEING DIVIDED BY A PERIPHERAL GROOVE FORMED ADJACENT THE AXIALLY INNER END OF THE TUBEEND RECEIVING BORE INTO ADJACENT BODY SECTIONS HAVING SUBSTANTIAL CROSS-SECTIONAL AREAS, SAID GROOVE PROVIDING AN AREA OF REDUCED CROSS-SECTION WHICH SEPARATES SAID ADJACENT BODY SECTIONS AND FORMS A RESTRICTION WHICH REDUCES THE FLOW OF HEAT IN A DIRECTION AXIALLY AWAY FROM SAID GROOVE TOWARD SAID SEALING MEANS DURING THE BONDING OPERATION; SAID FEMALE PART HAVING A TAPERED SEAT AGAINST WHICH THE OUTER FACE OF SAID LIP AT A ZONE CLOSE TO SAID FREE END WHICH IS TANGENT TO SAID TAPERED SEAT IS AXIALLY PRESSED AND THEREBY RADIALLY INWARDLY FLEXED TO ESTABLISH A RESILIENT FLUID-TIGHT CONNECTION BETWEEN SAID PARTS, SAID PARTS HAVING ABUTTING STOP SHOULDERS TO LIMIT DEFORMATION OF SAID LIP WITHIN ITS ELASTIC LIMIT WHEN SAID PARTS ARE CLAMPED TOGETHER.