US 4,575,400 AGranted

Apparatus for manufacturing corrugated tubes

AssigneeToyo Chemical Co., Ltd.

InventorsKoutarou Ueda, Noboru Hasegawa, Akio Machihara, Masaharu Kusaka, Kohei Orii, Yoshiro Noguchi

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Abstract

A method and apparatus for forming a corrugated tube having a smooth inner wall surface and a corrugated outer wall are provided. A first strip of resin material is wrapped around first portions of rollers arranged in a circular array and is helically wrapped around the first portions of the rollers each having equally spaced ridges therearound to form the corrugated outer wall. A second strip of resin material is fed from the interior of second portions of rollers arranged in a circular array onto the inner surface of the outer wall being manufactured and bonded thereto. The second strip bonded to the outer wall is wrapped around the second portions of the rollers each having a smooth surface to form the smooth inner wall.

Claims15

Dependent claims

Apparatus for manufacturing a corrugated tube having a smooth inner wall surface along the length of the tube and axially extending spiral convolutions to form a corrugated outer wall in longitudinal cross-section comprising:

a roller assembly composed of a plurality of rollers arranged in a circular array so as to define an imaginary cylinder about its central axis with the longitudinal axes of said rollers offset with respect to the central axis of the imaginary cylinder while the rollers are maintained in parallel to each other;
first feeding means for continuously feeding a first strip of synthetic resin material in a softened state transversely onto the periphery of said roller assembly;
drive means for rotating each of said rollers at the same speed;
each of said rollers having a first portion with a plurality of axially equally spaced annular ridges therearound and a second portion with a smooth surface, the ridges of the respective rollers being arranged such that the associated ridges of each adjacent roller are successively aligned with each other along a spiral path;
pressure roller means having annular ridges therearound adapted to mate with recesses defined by each adjacent ridge of at least one of said rollers,
whereby said first strip is spirally wrapped around the first portions of the rollers while being axially advanced and the first strip is formed with corrugations along said ridges as said first strip is wrapped around said first portions of said rollers, to thereby form said corrugated outer wall;
and
second feeding means disposed in the interior of said roller assembly for continuously feeding a second strip of synthetic resin material in a softened state, from the inside of the outer wall being manufactured, onto the inner surface of said outer wall so that the second strip is bonded to the inner surface of the outer wall and guided by said second portions of the rollers
and so that said second strip is spirally wrapped around said second portions of the rollers while being axially advanced together with the outer wall, to thereby form said smooth inner wall surface.

6 more elements

Apparatus for manufacturing a corrugated tube having a smooth inner wall surface along the length of the tube and axially extending spiral convolutions forming a corrugated outer wall in the longitudinal cross-section, comprising:

a roller assembly formed of a plurality of elongated rollers arranged in a circular array to define an imaginary cylinder about the central axis thereof, the longitudinal axes of the elongated rollers being offset with respect to the central axis of the imaginary cylinder and arranged in parallel to each other, each roller including a first portion having a plurality of annular ridges therearound equally spaced apart in the axial direction of the roller, and a second portion having a smooth surface, the ridges of the respective rollers being arranged so that the ridges of the adjacent rollers are successively aligned to form a spiral path around the imaginary cylinder,
drive means for rotating said rollers substantially at the same speed,
at least one pressure roller having annular ridges therearound, said pressure roller being situated adjacent to one of the rollers so that the annular ridges of the pressure roller are disposed in spaces between the adjacent two ridges of the roller,
first feeding means for continuously feeding a first strip of synthetic resin material in a softened state transversely onto the periphery of the first portion of the roller assembly so that the first strip is spirally wrapped around the first portion of the rollers while being axially advanced to thereby form a corrugated cylindrical tube, said corrugated outer wall being formed by means of the rollers and the pressure roller, and
second feed means situated in the roller assembly for continuously feeding a second strip of synthetic resin material in a softened state transversely onto the outer periphery of the second portion of the roller assembly from the inside of the corrugated out wall so that the second strip is spirally wrapped around the second portion of the rollers while being axially advanced together with the corrugated outer wall and is bonded to the innermost portions of the corrugated outer wall to thereby form a smooth inner wall.

2 more elements

Dependencies are inferred from the claim text.