Self restraining gasket and pipe joint
A restraining element for preventing separation of a pipe joint used to join a bell end of a female plastic pipe to the male end of a mating pipe. The restraining element is formed from a compressible body of elastomeric material, the compressible body having a segmented metal ring located therein with gripping teeth for engaging an outer surface of the mating male pipe. The ring segments making up the segmented metal ring are oriented such that the gripping teeth of the ring segments are out of contact with and initially angled away from the outer surface of the male plastic pipe. The teeth of the annular gasket are forced into engagement with the exterior surface of the male plastic pipe as the pipe joint is assembled. The teeth are oriented to allow movement of the male pipe in a first direction relative to the female bell end opening during assembly, but to resist movement in a opposite direction after the pipe joint has been assembled.
1. A self-restrained pressure gasket for insertion within an annular groove provided in a bell end opening of a female pipe capable of both joining and sealing the female plastic pipe to a mating male pipe having an interior surface and an exterior surface, the bell end defining an end face at the opening, gasket comprising:
an annular gasket body made of a resilient elastomeric material, the annular gasket body having an inner circumferential region and an outer circumferential region, wherein an end of the gasket body lies substantially at the end face at the opening;
a hardened ring located within the material of the gasket body so that the ring is at least partially embedded within the resilient elastomeric material, the hardened ring having an inner circumferential surface, an outer circumferential surface, front and rear end faces and opposing sides, the hardened ring having a single slit at one circumferential location to allow for expansion and contraction of the ring;
at least one row of teeth located on the inner circumferential surface of the hardened ring for engaging selected points on the exterior surface of the mating male plastic pipe.
2. The self-restrained pressure gasket of claim 1 , wherein the hardened ring is located within a pocket provided in the elastomeric material of the gasket body, whereby the hardened ring is allowed limited movement during expansion and contraction of the gasket.