Joint restraint for molecularly oriented pipe and method of manufacture using a groove formed on a spigot

Abstract

A pipe joining system and pipe joint are shown in which two sections of plastic pipe, particularly molecularly oriented pipe, are joined. A first section of plastic pipe has a female, belled pipe end with a mouth opening and having an exterior surface, an interior surface and having an interior circumferential recess formed in the belled pipe end adjacent the mouth opening on the interior surface thereof. A second section of plastic pipe having a mating male plastic pipe end has an interior surface and exterior surface. The exterior surface has a circumferential groove formed at one circumferential location thereof which is alignable with the interior recess formed within the mouth opening of the belled pipe end as the pipe joint is made-up. The circumferential groove is formed during the manufacture of the plastic pipe by expanding the pipe against a restraining element located in the interior of an expansion mold. The respective grooves contain elements of a restraint system which form a restrained joint when the male and female pipe sections are assembled.