Plastic pipe adhesive joint

Abstract

A method of joining two pipe ends, by forming male threads on an end of a first pipe with a steep taper angle, forming matching female threads on an end of a second pipe, and applying adhesive material to the threads before twisting the pipes to fully engage the male and female threads, thereby spreading the adhesive material across adjacent load-bearing surfaces of the threads. The threads have multiple start locations for thread engagement so that the pipe ends may be twisted to achieve full engagement in less than one full relative rotation. The male and female threads are formed with a squeeze angle between matching surfaces of the threads between 0.5 and 5.0 degrees. The finished joint provides immediate leak-tightness, and immediate tensile, compressive and torsional strength and does not protrude outside of the pipe profile. The technique may also be used to join pipes constructed of dissimilar materials, particularly by using a coupler that has the appropriate threading, and securing the coupler to a non-threaded pipe end using any convenient means, such as a mechanical fit, or fusion bonding.

Dependencies are inferred from the claim text.