Abstract: Disclosed is apparatus and methods for the stretch forming of an elongated hollow metal section, such as an aluminum extrusion. The apparatus and methods use a flexible constraining means which surrounds at least a portion of the outer periphery of the elongated hollow metal section to constrain and support the walls of the elongated hollow metal section against the forces produced within the interior of the hollow metal section during the reshaping of the extrusion by the stretch forming operation. The apparatus and methods disclosed herein resist wrinkles, crimps and bulges being formed in the walls of the elongated hollow metal section during the stretch forming and reshaping thereof.

Abstract: Disclosed is apparatus and a method for the stretch forming of an elongated hollow metal section, such as an aluminum extrusion. The apparatus and method uses one or more constraining means secured to the forming die and a die extension to constrain and support the walls of the elongated hollow metal section against the forces produced by air pressure within the interior of the hollow metal section. The apparatus and methods disclosed herein prevent the formation of wrinkles, crimps and bulges in the walls of the elongated hollow metal section during the stretch forming and reshaping thereof.

Abstract: Disclosed is apparatus and a method for the stretch forming of an elongated hollow metal section, such as an aluminum extrusion. The apparatus and method of this invention uses a collapsible and expandable articulated mandrel positioned inside portions of the elongated hollow metal section to constrain and support the internal wall surfaces of the elongated hollow metal section against the reshaping forces imposed on the interior of the hollow metal section during the stretch forming operation. The mandrel disclosed herein prevents the formation of wrinkles and crimps being formed in the walls of the elongated hollow metal section during the stretch forming and reshaping thereof.

Abstract: A tool device for supporting one or more walls of an elongated hollow member located in a recess of a die for bending said member over a surface of the die while said member is in a stretched condition. The tool device comprises a plurality of segments held together in a snake-like arrangement by at least one cable extending through the segments. Opposed ends of the cable are provided with means for connecting the cable to opposed clamp assemblies of stretch bend apparatus.