Large diameter double-walled plastic pipe

Abstract

Non-releasable, double-walled, molded, large-diameter, corrugated plastic pipe having walls made of high density polyethylene, PVC or polypropylene of sufficient thickness so as to be rigid but elastic and therefore relatively inflexible and having an integral automatically locking female coupling at one end, with access to its latching members at its exterior, and a method of manufacturing multiplex thereof by a continuous molding process. The pipe has a smooth interior wall and a corrugated outer wall integral therewith. Only minor auxiliary cutting operations are required to separate portions thereof into individual plastic pipe sections, each having the automatic-locking coupling at one of its ends. The coupling is supported on the corrugated pipe by a frustoconically shaped collar which functions as a guide for proper alignment as two sections of pipe are united into latched relation. Each coupling has a plurality of hinged latching members carrying inwardly extending lugs which are cammed outwardly on their advancing faces to permit reception of the opposite end of a similarly formed pipe and are formed with a latching mechanism on their retracting faces in a manner designed to provide non-releasable locking action therebetween. The double-walled pipe, when so connected to each other, produce a smooth continuous interior wall.