Joining thermoplastic pipe to a coupling

A method of joining a pipe to a coupling, said pipe being capable of being constricted and having in its free state an internal diameter and an external diameter, said coupling comprising a rigid tubular insert having external circumferential projections separated by circumferential grooves, and a rigid tubular sleeve having a fixed largest internal diameter less than the external free state diameter of said pipe, the method comprising:

• causing relative approach of said sleeve and said pipe to cause said sleeve to pass relatively over an end of said pipe to a temporary location remote from said end of said pipe, said external and internal free state diameters of said pipe being constricted as said sleeve passes over it and then subsequently recovering to establish an end portion of said pipe which is in a free state unconstricted by said sleeve, said unconstricted end portion extending from said end of said pipe to said sleeve;
• inserting said insert through said end of said pipe into said unconstricted end portion, the maximum outer diameter of said projections of said insert being at most equal to the internal free state diameter of said pipe;
• and causing relative movement of said sleeve toward said end of said pipe until said Pipe is gripped between said projections and said sleeve.