Method of making corrugated plastic pipe with integral coupler collars

Claim 1

A method of making plastic pipes each having an elongate tubular corrugated body and an integral enlarged coupler collar on one end of each body; said method comprising continuously extruding a tube of hot plastic material into a blow molding zone defined by a series of cooperating pairs of forwardly moving die blocks, while molding annular corrugations of alternating ribs and valleys along successive closely spaced, elongate portions of the tube to produce predetermined corrugated lengths of the tube during forward movement thereof through the molding zone, while also molding each of those portions of the tube between the corrugated lengths into an enlarged relatively short sleeve of an inner shape and size capable of circumscribing a circle of a diameter greater than the outer diameter of the ribs during forward movement of the tube through the molding zone, and while molding a plurality of spaced latch members integral with and projecting inwardly around the interior of each sleeve adjacent opposite sides of the median longitudinal center thereof and wherein the latch members are of such size and shape as to fit in at least one valley of a cut-end portion of the corrugated lengths, transversely severing said tube intermediate the ends of the respective sleeves to form each sleeve into a pair of separate collars integral with and projecting axially from the proximal ends of adjacent corrugated lengths so that some of said latch members are positioned within both of the separate collars formed by severing each sleeve, and transversely severing each of said corrugated lengths intermediate the ends thereof so that each pipe thus formed has a collar on one end only thereof adapted to receive therein the corrugated opposite end portion of anoter like pipe.

Claim 2

A method of making plastic pipes each having an elongate tubular corrugated body and an integral enlarged coupler collar on one end of each body; said method comprising continuously extruding a tube of hot plastic material into a blow molding zone defined by a series of cooperating pairs of forwardly moving die blocks, while molding annular corrugations of alternating ribs and valleys along successive closely spaced, elongate portions of the tube to produce predetermined corrugated lengths of the tube during forward movement thereof through the molding zone, while also molding each of those portions of the tube between the corrugated lengths into an enlarged relatively short sleeve of an inner shape and size capable of circumscribing a circle of a diameter greater than the outer diameter of the ribs during forward movement of the tube through the molding zone, and while molding a plurality of spaced latch members integral with and projecting inwardly around the interior of each sleeve adjacent opposite sides of the median longitudinal center thereof and wherein the latch members are of such size and shape as to fit in at least one valley of a cut-end portion of the corrugated lengths, transversely severing said tube intermediate the ends of the respective sleeves to form each sleeve into a pair of separate collars integral with and projecting axially from the proximal ends of adjacent corrugated lengths so that some of said latch members are positioned within both of the separate collars formed by severing each sleeve, and transversely severing each of said corrugated lengths intermediate the ends thereof so that each pipe thus formed has a collar on one end only thereof adapted to receive therein the corrugated opposite end portion of anoter like pipe.

Claim 14

A method of continuously making corrugated plastic pipes of predetermined length having enlarged annular coupler collars on one end thereof, said method comprising extruding a tube of plastic material into a molding zone, while successively molding the tube in its course through the molding zone into relatively short annular sleeves and integral relatively long annularly corrugated lengths arranged in alternation, with the inner diameter of the sleeves being greater than the outer diameter of the corrugated lengths, while also molding a plurality of spaced latching members integral with and projecting inwardly around the interior of each sleeve adjacent opposite sides of the median longitudinal center thereof with the size and shape of the latching members being such as to fit in the valleys of the corrugations in a cut-off end of said corrugated lengths of the tube, delivering the thus molded tube from the molding zone at a predetermined speed while directing the tube delivered from the molding zone through a cutting zone, transversely severing one of the sleeves along a line about at its median longitudinal center as it passes through the cutting zone to form a pair of separate collars therefrom, then transversely severing the next succeeding corrugated length of the tube along a line about halfway between the previously severed sleeve and the next succeeding sleeve as the corrugated length passes through the cutting zone, and repeating the said steps of severing in that order as succeeding sleeves and corrugated lengths pass through the cutting zone.

Claim 15

A method of continuously making corrugated plastic pipes of predetermined length having enlarged annular coupler collars on one end thereof, said method comprising extruding a tube of plastic material into a molding zone, while successively molding the tube in its course through the molding zone into relatively short annular sleeves and integral relatively long annularly corrugated lengths arranged in alternation, with the inner diameter of the sleeves being greater than the outer diameter of the corrugated lengths, while also molding a plurality of spaced latching members integral with and projecting inwardly around the interior of each sleeve adjacent opposite sides of the median longitudinal center thereof with the size and shape of the latching members being such as to fit in the valleys of the corrugations in a cut-off end of said corrugated lengths of the tube, delivering the thus molded tube from the molding zone at a predetermined speed while directing the tube delivered from the molding zone through a cutting zone, transversely severing one of the sleeves along a line about at its median longitudinal center as it passes through the cutting zone to form a pair of separate collars therefrom, then transversely severing the next succeeding corrugated length of the tube along a line about halfway between the previously severed sleeve and the next succeeding sleeve as the corrugated length passes through the cutting zone, and repeating the said steps of severing in that order as succeeding sleeves and corrugated lengths pass through the cutting zone.

Claim 16

A method of making plastic pipes each having an elongate corrugated body and an integral enlarged coupler collar on one end of each body; said method comprising continuously extruding a tube of hot plastic material forwardly into a blow molding zone defined by a series of cooperating pairs of forwardly moving die blocks, while molding annular corrugations of alternating ribs and valleys along successive closely spaced and elongate portions of the tube to form corrugated body-forming lengths of the tube during movement thereof through the molding zone, while also molding each portion of the tube between the body-forming lengths into a relatively short sleeve of an inner diameter greater than the outer diameter of the ribs during forward movement of the tube through the molding zone, while molding a plurality of spaced latch members integral with and projecting inwardly around the interior of each sleeve and wherein the latch members are of such size and shape as to fit in at least one valley of a cut-end portion nof thE corrugated lengths delivering the thus molded tube from the molding zone at a predetermined speed and feeding the tube forwardly through a cutting zone, transversely severing the tube in its course through the cutting zone in such relation to said sleeves as to form the same into annular collars projecting axially from at least one of the ends of the body-forming lengths sof the tube and having inwardly projecting latch members integrally formed on the collars, and transversely severing each of said corrugated lengths intermediate the ends thereof so that each pipe thus formed has a collar on one end only thereof adapted to receive therein the corrugated opposite end portion of another like pipe.

Claim 17

A method of making plastic pipes each having an elongate corrugated body and an integral enlarged coupler collar on one end of each body; said method comprising continuously extruding a tube of hot plastic material forwardly into a blow molding zone defined by a series of cooperating pairs of forwardly moving die blocks, while molding annular corrugations of alternating ribs and valleys along successive closely spaced and elongate portions of the tube to form corrugated body-forming lengths of the tube during movement thereof through the molding zone, while also molding each portion of the tube between the body-forming lengths into a relatively short sleeve of an inner diameter greater than the outer diameter of the ribs during forward movement of the tube through the molding zone, while molding a plurality of spaced latch members integral with and projecting inwardly around the interior of each sleeve and wherein the latch members are of such size and shape as to fit in at least one valley of a cut-end portion nof thE corrugated lengths delivering the thus molded tube from the molding zone at a predetermined speed and feeding the tube forwardly through a cutting zone, transversely severing the tube in its course through the cutting zone in such relation to said sleeves as to form the same into annular collars projecting axially from at least one of the ends of the body-forming lengths sof the tube and having inwardly projecting latch members integrally formed on the collars, and transversely severing each of said corrugated lengths intermediate the ends thereof so that each pipe thus formed has a collar on one end only thereof adapted to receive therein the corrugated opposite end portion of another like pipe.