US Patent 7648176 Pipe joint

A joint for joining the ends of two pipes has a socket (or box) on the end of one pipe into which the end of the other pipe is inserted. The part of the socket which surrounds the inserted pipe has an external tapered surface. A correspondingly tapered sleeve surrounds the socket and can be moved axially to apply a compressive force to the taper on the socket which is thus compressed inward against the inserted pipe end to frictionally grip the inserted pipe end.