US Patent 7845686 Restrained pipe joining system for plastic pipe

A restrained pipe joining system is shown comprising male and female ends each having aligned circumferential grooves which form a canal for passage of a locking key strap. During manufacture, the female belled end is sequentially formed over a Rieber style gasket and then over a ring shaped casing member having an inner circumferential groove formed on its inner circumferential surface. Preferably, the ring shaped casing has circumferentially spaced teeth that act as a pipe stop in cooperation with an outer circumferential groove on the male spigot to index the pipes to be coupled.