Patent ID: 9149973
Filing Date: 2015-10-06
Classification: B29C,B29K,B29L

Abstract:
1. A method for making flexible tubing with annular corrugations from a sleeve of uncured rubber, the method comprising: placing a sleeve of uncured rubber on a mandrel; placing an external forming member around said mandrel and sleeve, said external forming member including a plurality of annular discs and a flexible tubular support for loosely positioning said discs in axially spaced relation and in approximate axial alignment, said flexible tubular support having annular corrugations with alternating internal and external ridges and grooves and said discs being loosely supported in said external grooves; radially expanding said sleeve with fluid pressure to force annular portions of said sleeve into said internal grooves; sliding an aligning tube axially along said external forming member to engage said discs and urge them into accurate axial alignment with one another to assure uniformity when preliminary annular impressions are formed in said uncured rubber sleeve, wherein an interior end edge of said disc aligning tube is beveled to assure that initial engagement between a misaligned disc and the disc aligning tube urges the engaged disc in a radial direction into accurate axial alignment; axially collapsing said external forming member to squeeze said annular portions of said sleeve in said internal grooves to form the preliminary annular impressions in said sleeve; removing said sleeve from said mandrel and said external forming member; placing said sleeve on a curing mandrel in an axially foreshortened condition with said preliminary annular impressions spaced apart a predetermined axial distance; and heating said sleeve while on said mandrel to cure said sleeve and produce a length of annularly corrugated rubber tubing.