US 4,308,228 AGranted

Method for making flexible corrugated rubber tubing

OwnerVance M. Kramer, Sr., Vance M. Kramer, Jr.inventors

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Abstract

A method for making flexible tubing with helical corrugations by forming two tube lengths simultaneously while superposed one on top of another. Two extruded sleeves of different diameter formed of uncured vulcanizable stock are slid successively in superposed relation over an elongated internal forming member having a helical surface form with helical ridges and grooves. The resulting assembly is then wrapped with a flexible cord under tension such that successive turns of the cord are in spaced, generally parallel relation and in the grooves of the forming member to press adjacent portions of the two sleeves into the grooves. The sleeves are heat-treated in this wrapped condition to form two flexible, corrugated lengths of tubing simultaneously. The cord is then unwrapped from the lengths of tubing and the lengths are removed in reverse order of assembly.

Claims4

Dependent claims

A method for making flexible tubing with helical corrugations comprising telescoping a first uncured rubber sleeve over an elongated internal forming member having a surface formed with helical ridges and grooves;

telescoping a second uncured rubber sleeve over said first uncured rubber sleeve;
wrapping a flexible element about said sleeves under tension with successive turns of said element in spaced, generally parallel relation and in alignment with the helical groove of said internal forming member to press adjacent portions of said sleeves into the groove of said internal forming member in superposed relation;
heat treating said sleeves while in said wrapped superposed condition, to form a first flexible corrugated tube length of relatively small diameter and a second flexible corrugated tube length of relatively large diameter;
unwrapping said flexible element from said tube lengths;
and separating said tube lengths from each other and from the forming member.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application: 06/190,414Filed 24 Sep 1980 · continuation in part
Priority: 23 Oct 1979
Granted: 29 Dec 1981
Term ends: Not estimatedThe source records don’t support an estimate.

Classification11 codes

B29C 53/305
Of tubes: using a cording process
B29C 31/002
Handling, e.g. feeding of the material to be shaped , storage of plastics material before moulding; Automation, i.e. automated handling lines in…:…
B29C 63/20
Using tubular layers or sheathings: using pressure difference, e.g. vacuum
B29K 2021/00
Use of unspecified rubbers as moulding material