Patent ID: 6412765
Filing Date: 2002-07-02
Classification: B21D

Abstract:
An expansible mandrel of a required depth having at least three side wall components movably coupled thereto and a movable base component, the outer surfaces of said side wall components defining a cross-sectional shape of said mandrel which it is desired to expand and contract in a predetermined manner, said base component mechanically communicating with said side wall components such that motion of said base in one direction causes motion of said side wall components in a direction perpendicular to said one direction to expand or contract said cross-sectional shape, wherein mechanical communication between base and side wall components is achieved through a primary cam component connected to said base component to be movable therewith and extending internally of said mandrel away from said base component and generally in the direction of movement thereof, said primary cam component having at least one cam surface on a side thereof remote from the connection with the base component and against which a cam follower of a secondary cam component bears, said secondary cam component having at least one cam surface against which a cam follower provided on one of said side wall components bears, the direction of motion of said secondary cam component being perpendicular to that of said primary cam component, and the direction of motion of said side wall components being perpendicular to that of the secondary cam component during expansion of the mandrel.