Patent ID: 6260402
Filing Date: 2001-07-17
Classification: B21D,E04B

Abstract:
A method for shaping a piece of bendable sheet material having a distal side and a proximal side and first and second ends, comprising:a. forming a closed perimeter opening in said piece, said closed perimeter opening having a first shape;b. bending said piece along a flange bend line so that said piece adopts a first intermediate position, said flange bend line dividing said piece into a flange that contains said closed perimeter opening and a web to the other side of said flange bend line, said flange having distal and proximal sides, a top disposed away from said flange bend line and a bottom coincident with said flange bend line; andc. bending said web along a transverse bend line that divides said web into a seat and a back and said flange into a seat flange and a back flange, so that said piece adopts a second position, said transverse bend line lying near said closed perimeter opening, while bending said web along said transverse bend line simultaneously supporting portions of said distal and proximal sides of said flange such that said seat flange and said back flange are swung inwardly on each other, such that portions of said seat flange and said back flange near said ends of said part are bent out of line and lie at an angle to each other, said bending being carried out with a force sufficient to create compression forces in portions of said flange near said transverse bend line, causing portions of said flange to plasticize and flow into said closed perimeter opening in said flange, such that said closed perimeter of said opening is deformed by said material flow and said opening adopts a second smaller shape than said first shape.