Mold blocks for forming coupler collar integral with pipe

Claim 2

A pair of mold blocks adapted for forming an enlarged coupler collar on a corrugated plastic pipe being molded therein, said pair of mold blocks having corresponding concave mold surfaces which cooperate to define a generally cylindrical mold cavity extending from one end of the cooperating pair of mold blocks to the opposite end, each mold block having a series of semicircular transverse alternating ribs and valleys forming a corrugated portion on the concave mold surface and extending from one end of the mold block and over a predetermined axial length of the mold surface, the ribs and valleys of each of the mold blocks cooperating to form uninterrupted annular ribs and annular valleys in a portion of the mold cavity, a semicylindrical wall forming the remaining portion of the concave mold surface and extending from adjacent said corrugated portion to the opposite end of the mold block and having a diameter substantially greater than that of the valleys in the corrugated portion of the mold surface, the semicylindrical wall of each of the mold blocks cooperating to form a relatively enlarged generally cylindrical portion of the mold cavity, a plurality of arcuately spaced relatively short projections extending radially inwardly from said semicylindrical wall and spaced axially inwardly a short distance from said opposite end of the pair of cooperating mold blocks.

Claim 3

A pair of mold blocks according to claim 1 wherein said series of alternating ribs and valleys extends over at least half the axial length of said mold surface.

Claim 4

A pair of mold blocks according to claim 1 wherein the inner peripheries of the ribs and valleys are substantially flat in the axial direction and wherein the side walls of the ribs are substantially flat and form an acute angle with a plane normal to the axis of the mold cavity.

Claim 5

A pair of mold blocks according to claim 1 wherein said semicylindrical wall has an axial length of at least twice the distance between corresponding points on adjacent valleys in the corrugated portion of said mold surface.

Claim 6

A pair of mold blocks according to claim 1 wherein the valleys in the corrugated portion of said mold surface have a diameter of about 4 1/2 inches and wherein the semicylindrical wall has a diameter of about 4 5/8 inches.

Claim 7

A pair of mold blocks according to claim 1 wherein each mold block has an axial length of about 4.17 inches and wherein said semicylindrical wall has an axial length of at least about 1.39 inches.

Claim 8

A pair of mold blocks according to claim 1 wherein said projections are wedge-shaped and havE one opposing surface thereof lying in a plane which is angularly oriented with respect to the axis of said mold cavity and converging inwardly from said opposite end of the mold blocks and have a second opposing surface lying in a common plane substantially perpendicular to the axis of said mold cavity.

Claim 9

A pair of mold blocks for use in a continuous blow molding machine employing two endless series of abutting forwardly moving cooperating pairs of mold blocks, said pair of mold blocks having corresponding concave mold surfaces which cooperate to define a generally cylindrical mold cavity extending from one end of the pair of mold blocks to the opposite end and being adapted for forming an enlarged coupler collar on a corrugated plastic pipe being molded therein, each mold block having a series of semicircular transverse alternating ribs and valleys forming a corrugated portion on the concave mold surface and extending from one end of the mold block and over at least about half the axial length of the mold surface, the ribs and valleys of each of the mold blocks cooperating to form uninterrupted annular ribs and annular valleys in a portion of the mold cavity, a semicylindrical wall forming the remaining portion of the concave mold surface and extending from adjacent said corrugated portion to the opposite end of the mold block and over an axial length of at least about twice the distance between corresponding points on adjacent valleys in the corrugated portion of the mold surface, said semicylindrical wall having a diameter substantially greater than that of the valleys in the corrugated portion of the mold surface, the semicylindrical wall of each of the mold blocks cooperating to form a relatively enlarged generally cylindrical portion of the mold cavity, a plurality of arcuately spaced projections positioned on the semicylindrical wall and extending radially inwardly therefrom, said projections being located on said semicylindrical wall so as to be arcuately spaced substantially equally apart around the interior of the cylindrical portion of the mold cavity and axially spaced substantially equally inwardly from said opposite end of the mold blocks, and gear means integral with an exterior surface of the mold block for engaging with drive means in a blow molding machine to move the pair of mold blocks simultaneously in the blow molding machine.

Claim 10

A pair of mold blocks for use in a continuous blow molding machine employing two endless series of abutting forwardly moving cooperating pairs of mold blocks, said pair of mold blocks having corresponding concave mold surfaces which cooperate to define a generally cylindrical mold cavity extending from one end of the pair of mold blocks to the opposite end and being adapted for forming an enlarged coupler collar on a corrugated plastic pipe being molded therein, each mold block having a series of semicircular transverse alternating ribs and valleys forming a corrugated portion on the concave mold surface and extending from one end of the mold block and over at least about half the axial length of the mold surface, the ribs and valleys of each of the mold blocks cooperating to form uninterrupted annular ribs and annular valleys in a portion of the mold cavity, a semicylindrical wall forming the remaining portion of the concave mold surface and extending from adjacent said corrugated portion to the opposite end of the mold block and over an axial length of at least about twice the distance between corresponding points on adjacent valleys in the corrugated portion of the mold surface, said semicylindrical wall having a diameter substantially greater than that of the valleys in the corrugated portion of the mold surface, the semicylindrical wall of each of the mold blocks cooperating to form a relatively enlarged generally cylindrical portion of the mold cavity, a plurality of arcuately spaced projections positioned on the semicylindrical wall and extending radially inwardly therefrom, said projections being located on said semicylindrical wall so as to be arcuately spaced substantially equally apart around the interior of the cylindrical portion of the mold cavity and axially spaced substantially equally inwardly from said opposite end of the mold blocks, and gear means integral with an exterior surface of the mold block for engaging with drive means in a blow molding machine to move the pair of mold blocks simultaneously in the blow molding machine.

Claim 11

A pair of mold blocks according to claim 8 wherein said projections are defined by separate wedge-shaped segments secured to said semicylindrical wall and having one surface thereof lying in a plane which is angularly oriented with respect to the axis of said mold cavity and converging inwardly from said opposite end of the mold blocks and having a second surface thereof lying in a plane substantially perpendicular to the axis of said mold cavity.