Patent ID: 9505164
Filing Date: 2016-11-29
CPC Classification: A61M,B29C,B29D,B29K,B29L,F16L

Claim Text:
1. A method of forming a length of helically externally ribbed plastic tubing, with at least a portion of the tubing length being formed changing progressively in diameter, comprising the steps of: a) providing a plurality of elongate rods that are canted relative to an imaginary central axis and that converge as the rods approach a wrapping station at a location along the central axis, with each rod having a different centerline about which the rod is individually turned at a same speed of rotation and in a same clockwise or counterclockwise direction of rotation; b) continuously extruding both a tape-like web of thermoplastic material and a bead of thermoplastic material toward the wrapping station; c) continuously helically winding both 1) the tape-like web of extruded thermoplastic material circumferentially and 2) the bead of thermoplastic material around the plurality of turning rods at the wrapping station so the web of thermoplastic material forms a continuous tubular wall of a length of tubing that advances away from the wrapping station along the central axis as the continuous tubular wall is formed, with one edge region of each newly wound convolution of the web overlapping and bonding to an adjacent previously wound convolution of the web to thereby form the continuous tubular wall, and so that the bead of thermoplastic material forms a rib that is integrally connected to and helically wound externally about the tubular wall to provide reinforcement thereto; and d) progressively performing all three of 1) adjusting the speed of rotation of the turning rods, 2) radially inwardly or radially outwardly moving the turning rods transversely relative to the central axis, and 3) altering a canting of the rods relative to the central axis, concurrently with and while continuing to wind the thermoplastic materials of the web and the bead at the wrapping station to form the continuous tubular wall, to progressively alter the diameter of at least the portion of the length of tubing during formation of the continuous tubular wall at the wrapping station.