Apparatus and method for the stretch forming of elongated hollow metal sections
AssigneeAluminum Company of America
InventorsRobert E. Weykamp, Robert P. Evert
Life of this patent
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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.
Claims14
Apparatus for the stretch forming of an elongated hollow metal section into a predetermined contour, comprising means to grip the opposed ends of said elongated hollow metal section, a forming die member having a forming die face and a die cavity in said die face adapted to receive at least a portion of said elongated hollow metal section, means to tension said elongated hollow metal section above its elastic limit, and at least one constraining means slidably secured directly to said forming die member and adapted to constrain those exterior surfaces of said portion of said hollow metal section that are adjacent to but not contained in said die cavity during the stretch forming thereof.
A method for the stretch forming of an elongated hollow metal section comprising the steps of gripping the opposed ends of said metal section and applying a tension to said metal section above its elastic limit, reshaping said metal section against a die member having a die cavity capable of receiving at least a portion of said metal section while said metal section is tensioned, placing one or more constraining means slidably secured to said die member about those portions of said metal section not received in said die cavity and introducing air at greater than atmospheric pressure into the interior of said metal section whereby said metal section is shaped to conform to the shape of said die cavity and said constraining means.
Dependencies are inferred from the claim text.