A pipe sealing gasket is shown which is designed to be received within a groove provided within the belled, socket end of a plastic pipe. The sealing gasket has a body formed of resilient material and has a retainer ring embedded therein which circumscribes the gasket body. The groove in the plastic pipe is preformed during the manufacture of the plastic pipe and the gasket is installed thereafter. The gasket nominal diameter exceeds the internal diameter of the belled pipe end. The retainer ring is placed within the body of the sealing gasket at a precisely determined location which most effectively retains the ring in position while withstanding the forces of the assembly of the pipe joint.

A restraining gasket for both sealing and preventing separation of a pipe joint used to join a bell end of a female ductile iron pipe to the male end of a mating ductile iron pipe. The gasket has a body formed from a compressible elastomeric material having a hardened metal ring located therein with gripping teeth. The hardened ring has an opening at one point in its circumference which is filled with rubber. The rubber-filled gap ensures that the gasket body seals first prior to engagement of the gripping teeth as the pipe joint is assembled.

A seismic coupling is provided for coupling a first longitudinal section of plain end plastic pipe to a second longitudinal section of plastic pipe. The coupling is provided in two halves with a left half being initially installed on the plain end of the first section of pipe. An internal shoulder is fused onto the first section of pipe and a right half of the coupling is then fused onto the left half to capture the first end of pipe within the coupling. The second pipe end is then installed within an end opening of the coupling and held in position by a connector installed between the right half of the coupling and the second pipe end. Internal seals are provided for sealing the first and second pipe ends within the interior of the coupling.

A combination sealing and restraint system for an as-cast ductile iron fitting is shown for both sealing and preventing separation of an iron pipe fitting and a mating male pipe. The restraint system includes both a sealing ring and a combination gripping ring which are installed in a groove provided in a mouth region of the iron fitting. The gripping ring has teeth on an inner surface which are initially angled away from an outer surface of the male pipe. The teeth are forced into engagement with the exterior surface of the mating male pipe as the pipe joint at the fitting is assembled. The teeth are oriented to allow movement of the male pipe in a first direction relative to an end opening of the fitting during assembly, but to resist movement in a opposite direction after the fitting joint has been assembled. The sealing ring and gripping ring are installed in the annular groove of the as-cast iron fitting after the iron casting operation at the factory.