This is a restrained joint system which combines the advantages of both glue joint and flexible joint. The integral socket and spigot ends are joined together as in fig-5 and two spigot ends are joined with a double bell coupling as in fig-6. The hydraulic sealing is performed by elastomeric rubber rings, installed in circumferential groove on the integral socket and the coupling. The locking device, which provides longitudinal thrust restraint is inserted into a groove through an opening and can be removed to disassemble the joint at some later stage. Shear resistant plastic material is used for the locking strip. The necessity of thrust blocks are eliminated in this joint system.

* Lock joint with Double rubber ring can be manufactured on request.