Method for making a joint for a corrugated pipe segment

Abstract

A joint for coupling corrugated or ribbed pipe segments, including helical ribbed pipe segments, end-to-end includes a segment of corrugated or ribbed pipe having a plurality of corrugations or ribs spaced axially along the segment's outer surface, a spigot portion at an end of the segment where the corrugations or ribs have been partially removed to form annular bosses, an annular gasket positioned in the spigot portion, and a cylindrical coupling positioned over the spigot portion and gasket. The outer diameter of the coupling is substantially equal to the outer diameter of the corrugations or ribs, and the inner diameter of the coupling is larger than the outer diameter of the bosses such that a gap is formed between the coupling and the spigot portion. The gasket is sized to have a radial thickness slightly larger than the gap such that the gasket forms an air-tight seal between the spigot portion and the coupling when the spigot portion and gasket are inserted into the coupling. The gasket includes annular ribs extending from its outer circumference which are tapered at their leading edge to facilitate insertion of the spigot portion into the coupling, and are barb-shaped to resist separation of the spigot portion from the coupling once the joint is assembled.