Lock coupling for pipe

Claim 1

A FLUID-SEAL PIPE COUPLING ASSEMBLY OF THE TYPE ENGAGING TWO OR MORE PIPE ENDS IN FLUID SEAL RELATIONSHIP, COMPRISING IN COMBINATION: (A) AN OUTER COUPLING, HAVING INWARDLY TAPERED SHOULDERS AT EITHER END; (B) TWO OR MORE INNER PIPE MEMBERS COMMUNICABLY SUPPORTED WITHIN SAID COUPLING, SAID PIPE MEMBERS AND COUPLING DEFINING AN ANNULAR SPACE BETWEEN THEM COMMUNICATING WITH PRESSURE FLUID FLOWING THROUGH SAID PIPE MEMBERS; AND (C) A PRESSURE-FLUID SEALING GASKET THE ANNULAR SPACE BETWEEN AN INNER PIPE MEMBER AND AN OUTER COUPLING MEMBER TO SEAL THE JOINT SPACE WHILE THE FORWARD END OF THE GASKET IS EXPOSED TO FLUID PRESSURE AND THE BACK END IS URGED AGAINST A SUPPORTING SURFACE IN THE COUPLING, SAID GASKET BEING OF THE TYPE HAVING AN AXIALLY ELONGATED BODY DEFINING A BORE INCREASINGLY TAPERED FROM ITS BACK TO ITS FRONT END AND INCLUDING: (I) A RADIALLY, OUTWARDLY EXTENDING BACK RIM ADAPTED TO ABUT THE EXTERIOR ENDS OF A PIPE COUPLING; (II) AN INTERMEDIATE ELONGATED PORTION EXTENDING FORWARDLY FROM SAID BACK RIM AND OF SUFFICIENT LENGTH TO PERMIT LONGITUDINAL PLAY OF SAID GASKET WITHIN SAID COUPLING; (III) A MIDDLE CIRCUMFERENTIAL FACE EXTENDING RADIALLY OUTWARDLY FROM THE FORWARD END OF SAID ELONGATED PORTION AND ADAPTED TO ENGAGE A CORRESPONDING RADIALLY INWARDLY EXTENDING SHOULDER SURFACE IN A PIPE COUPLING UPON OUTWARD LONGITUDINAL PLAY OF SAID GASKET WITHIN SAID COUPLING; (IV) AT LEAST ONE TOOTHED, LUG RADIALLY INSET WITHIN SAID MIDDLE CIRCUMFERENTIAL FACE WITH TEETH EXTENDING REARWARDLY INTO SAID BORE SO AS TO GRIP A PIPE SUPPORTED THEREIN; (V) AN INNER SEALING LIP PRESENTED FORWARDLY OF SAID WEDGE-SHAPED SEALING LIP AND DEFINED AT TO ENGAGE THE INNER SURFACE OF A PIPE COUPLING; AND (VI) AN INNER SEALING LIP PRESENTED FORWARDLY OF SAID WEDGE-SHAPED SEALING LIP AND DEFINED AT ITS FRONT RIM BY A RADIALLY CONVERGING FEATHER LIP, SAID INNER SEALING LIP BEING PRE-TENSIONED TO A DIAMETER SMALLER THAN THE DIAMETER OF PIPE TO BE SUPPORTED GASKET.