Pipe coupling

Claim 1

A PIPE COUPLING COMPRINGING: (A) A CYLINDRICAL OUTER SHELL HAVING OPPOSITE ENDS PROVIDED WITH OPENINGS INTO WHICH PIPE SECTIONS MAY BE INSERTED; (B) A SLEEVE GASKET DISPOSED WITHIN THE SHELL AND HAVING SUFFICIENT LENGTH TO BRIDGE ACROSS ADJACENT ENDS OF THE PIPE SECTIONS; (C) THIS GASKET DEFINING A CYLINDRICAL BASE CONTACTING WITH AN INTERIOR SURFACE OF THE SHELL, THIS BASE BEING SPACED FROM THE EXTERIOR SURFACES OF THE PIPE SECTIONS; (D) THE GASKET FURTHER BEING FORMED WITH A PAIR OF ANNULAR FLAPS, ONE BEING CONNECTED TO EACH OF SAID OPPOSITE ENDS OF THE BASE, THESE FLAPS PROJECTING TOWARD ONE ANOTHER AND BEING LOCATED TO SURROUND AND BEAR AGAINST THE EXTERIOR SURFACES OF THE PIPE SECTIONS; (E) THE FLAPS BEING SPACED INWARDLY FROM THE INTERIOR SURFACE OF THE BASE TO FORM CIRCUMFERENTIAL RECESSES ENCIRCLING THE PIPE SECTIONS; (F) GASKET RINGS MOUNTED IN THE RECESSES TO SURROUND AND BEAR DIRECTLY AGAINST THE ANNULAR FLAPS, AND BEING MADE FROM A MATERIAL THAT WILL EXPAND WHEN SUBJECTED TO WATER REACHING THEM FROM BETWEEN ADJACENT ENDS OF THE PIPE SECTIONS, THEREBY FORCING THE ANNULAR FLAPS INTO FLUID-TIGHT RELATION WITH THE EXTERIOR SURFACES OF THE PIPE SECTIONS; (G) AND MEANS OPERABLE TO CONTRACT THE SHELL AGAINST THE SLEEVE GASKET TO COMPRESS THE LATTER AND THE GASKET RINGS AGAINST THE PIPE SECTIONS.