Abstract: A female pipe joint end 3 has a circular groove 11 and a rectangular circular groove 9 in its expanded inner periphery, and a mating male pipe joint end 6 has a tapered insertion edge 5 and a circular groove 7 in its outer periphery. The side wall of the groove 7 nearest the pipe end is perpendicular to the pipe axis; the opposite side wall is tapered. A packing seal 10 is disposed in the groove 11, and a continuous, relatively rigid locking ring 4 of synthetic resin is disposed in the groove 9 and snap fitted into the groove 7 during assembly. The ring 4 may have a bevelled lip 13, stepped inner and outer peripheries 15, 16, 17, or axial grooves 14 or holes 14' therethrough.

Abstract: A resin pipe joint is formed having a groove on the internal surface thereof adapted for receiving a seal. The mold for forming the pipe joint includes an external split mold and an internal mold core and sleeve with parts slidable relative to one another so that the elements form a space therebetween for injecting resin therein. Subsequently, while the injected resin is still in an unhardened state, the movable parts are moved to a second position relative to one another thereby providing an annular opening surrounding the resin body formed during the resin injecting step. A pressurized fluid is jetted through a passageway towards the internal periphery of the resin body to cause said resin body to bulge into the annular space thereby creating the internal groove or exteranl bulge in the resin body.

Abstract: In a pipe fitting adapted for joining plastic pipes by fusing, one or more notches are provided in portions of the pipe fitting to receive molten resinous material overflowing during the fusing operation.