Coherent stick of shirred tubing

摘要

A shirred stick of flexible tubing having a straight bore and an ordered pattern of shirred pleats has an improved coherency and is provided with one or more longitudinal grooves formed and extending on its outer surface from one end of the stick to the other. The grooves are formed by passing the shirred tubing through a restraining device comprising one or more blades disposed about a shirring mandrel to engage and longitudinally indent the outer surface of the shirred tubing.