Abstract: Apparatus for continuously making corrugated plastic pipes having enlarged coupler collars on one end thereof by continuously extruding a tube of plastic material into a molding zone especially constructed to mold the tube into a series of successively closely spaced body-forming lengths of annularly corrugated pipe with short integral relatively enlarged sleeves interconnecting adjacent body-forming lengths. The thus molded tube is severed along a line about halfway between opposite ends of each successive sleeve to form each sleeve into a pair of separate coupler collars, and the molded tube also is severed along a line about halfway between opposite ends of each corrugated body-forming length thereof. The molding zone is constructed so as to form a plurality of latch members integral with and extending interiorly from each coupler collar, which latch members are adapted to engage the ribs on the opposite end of another like pipe for releasable connection therewith.

Abstract: A corrugated plastic drainage pipe having a coupler integrally formed at one end thereof and wherein the coupler is in the form of an enlarged collar having an inner diameter and length so as to receive the end of a connecting pipe therein and having a plurality of spaced latching members integrally formed with and extending radially inwardly from the inner surface of the collar. The collar has sufficient flexibility and resiliency so that when the end of a corrugated pipe is inserted in the collar the latching member may be outwardly displaced momentarily with respect to one another for facilitating making the interconnection, and thereafter return and engage the ribs of the corrugated pipe and provide a releasable connection therewith.