Abstract: Apparatus for molding a plastic pipe having spaced apart enlarged sleeve portions formed therein along its length and wherein a tube of hot plastic material is continuously extruded into a blow molding zone formed by a series of cooperating pairs of forwardly moving die blocks having concave inner surfaces defining a body-forming mold cavity and an adjacent enlarged sleeve-forming mold cavity of internal dimension greater than that of the body-forming mold cavity, and wherein internal fluid pressure is applied within the hot plastic tube during forward movement of the same through the blow molding zone to expand the tube and mold the same against the body-forming and enlarged sleeve-forming mold cavities to thereby form the tube into body portions of predetermined tubular dimension and adjacent relatively enlarged sleeve portions.

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 plastic septic tank tee for use in a septic tank comprises an elongate tubular body member, a relatively short tubular branch member secured to the body member between the ends thereof and means carried by the branch member for aiding in anchoring and retaining the septic tank tee in operative position in the septic tank. The anchoring and retaining means preferably comprises a plastic split collar which is secured on the branch member and engages the outer side wall of the septic tank.

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.

Abstract: Corrugated plastic tubes simultaneously feeding from a plurality of sources are doffed, stacked in nesting relation and formed into bundles of a predetermined number of tubes in accordance with the present invention. The corrugated plastic tubes are produced in continuous length in separate production lines, cut to predetermined lengths, and fed along predetermined paths to respective doffing stations where the tubes are doffed into a common hopper positioned adjacent the doffing stations. Upon a predetermined number of the tubes being doffed into the hopper and accumulated in stacked and nested relation, the tubes are advanced to a bundling station where strapping machines secure pliable strapping elements around the stacked and nested tubes to form the same into compact bundles. The bundles are then removed from the bundling station ready for shipment or storage.