Reinforced flexible tubing and method of making same

摘要

A method for making helically corrugated rubber tubing with a helical reinforcing element embedded therein and with a relatively smooth interior surface. The tubing is formed with separate inner and outer tubular wall portions with fabric material in between. The inner and outer wall portions may be formed of different elastomeric compositions. Also the method provides for annular cuffs at the opposite ends of the tubing.

主权项

1. A method for making a length of flexible, helically corrugated rubber tubing with a helical spring-like reinforcing element embedded therein comprising the steps of:
sliding an uncured rubber inner sleeve over an assembly mandrel; sliding a helical, spring-like reinforcing element over the inner sleeve, wherein the inner sleeve has end portions that extend axially beyond respective ends of the helical reinforcing element; applying air pressure between the assembly mandrel and the inner sleeve to radially expand the inner sleeve into engagement with the surrounding reinforcing element; placing a heat shrinkable fabric around the helical reinforcing element such that the fabric covers the helical reinforcing element but does not cover the end portions of the inner sleeve that extend axially beyond the respective ends of the helical reinforcing element; applying sufficient heat to the fabric to shrink the fabric around and into tight engagement with the reinforcing element and the inner sleeve; sliding an uncured rubber outer sleeve over the shrunken fabric, the helical reinforcing element and the uncured rubber inner sleeve to form a tubular assembly, wherein the outer sleeve includes end portions that extend axially beyond the respective ends of the helical reinforcing element; rotating the tubular assembly about its axis while wrapping a cord about the outer sleeve to press portions of the outer sleeve into the spaces between adjacent convolutions of the reinforcing element; heating the tubular assembly with the cord wrapped thereon to cure the inner and outer sleeves with the helical reinforcing element and fabric embedded therein to provide a cured length of rubber tubing; and rotating the cured length of tubing about its axis in the reverse direction while unwrapping and removing the cord.