A polymer pipe has a length between a first end and a second end. The length and the first end have a first diameter and the second end is a belled end having a second diameter larger than the first diameter. An insert device is received within the second end and has an annular body and a spline groove formed in the annular body and facing radially inward. The insert device is pre-installed in the belled end during the belling process.

A method for manufacturing a plastic pipe including covering the teeth of a plurality of restraining segments circumferentially arranged and embedded within an annular gasket with a covering and placing the annular gasket on a mandrel with the covering arranged between the restraining segments and mandrel. The annular gasket and mandrel and are inserted into an end of a heated plastic pipe for forming a socket in the end of the plastic pipe, the socket including an annular cavity formed by the annular gasket. Upon removal of the mandrel from the socket, the covering functions to prevent acutely pointed teeth of the restraining segments from impinging upon the mandrel thereby allowing removal of the mandrel from the socket without removal of the annular gasket from the annular cavity.

A pipe belling process where a heated thermoplastic pipe end is forced over a sealing gasket on a forming mandrel, with the pipe being subsequently cooled to retain the gasket in an internal groove simultaneously formed in the pipe end. The sealing gasket is a two-component gasket with an elastic component and a plastic component. The elastic component is stretched over a portion of the plastic component during assembly with the plastic component acting as a belling ramp for the gasket during the subsequent pipe belling operation.

A polymer pipe has a length between a first end and a second end. The length and the first end have a first diameter and the second end is a belled end having a second diameter larger than the first diameter. An insert device is received or pre-installed within the second end and has an annular body with a seal part coupled to the annular body and a spline groove formed in the annular body and facing radially inward. Another polymer pipe is inserted in the belled end to form a pipe joint assembly and has a mating spline groove on the outer surface. The spline groove and mating spline groove axially align and receive a spline therein to axially interlock the two polymer pipes to form a pipe joint assembly.