Patent ID: 6591653
Filing Date: 2003-07-15
Classification: B21B,B21C,B21D,H01L

Abstract:
A method of producing a multi-gauge strip using cooperating molds, comprising the steps of:(a) providing a flat strip material having a thickness and including two sides each having an end, a widthwise direction extending between the two sides of the flat strip material and a lengthwise direction extending perpendicular to the widthwise direction; (b) forming the strip material into a semi-circular shape in the widthwise direction in the course of movement of the strip in a direction of progression; (c) forming the semi-circular shape of the strip material into a U-shape by elongating the two sides of the semi-circular shape thus making said two sides gradually longer along the lengthwise direction toward the direction of progression of said strip material and forming each leg of the U-shape with a straight end, the thickness of said two sides gradually decreasing along the lengthwise direction toward the direction of progression of said strip material, and simultaneously forming a curved protrusion along the inner circumference of the U-shape in between the legs of the U-shape, the thickness of the curved protrusion gradually decreasing along the lengthwise direction toward the direction of progression of said strip material; (d) forming the strip material, extending from the U-shape of the strip material, so as to equalize the legs of the U-shape to a constant height in which the thickness of the legs of the U-shape and the thickness of said curved protrusion, respectively, are evened out to uniformity in the lengthwise direction toward the direction of progression of said strip material; (e) forming the curved protrusion of the U-shape into a flat protrusion and at least a portion of each leg of the U-shape with a curve; and (f) flattening the curved portion of each leg of the U-shape so that the surface of each leg is substantially parallel to the surface of the flat protrusion but is located in a different plane.