System for production of circular hollow bodies - with internal grooving etc, has cup of material pressure cold rolled onto preshaped mandrel

摘要

The system is for the production of circular section hollow bodies having grooves or notches cut along longitudinal inside the hollow body. It has a cup or cap placed tightly on a rotating mandrel with the appropriate pattern of grooves forming devices on it. The cup or cap is then pressure formed and cold rolled onto the mandrel and has its external diameter reduced and its length extended during the pressure forming operation which applies it to the forming mandrel.