Apparatus and method for press forming

Claim 1

Apparatus for press forming a flat metal blank to cold form an angle in said blank, said apparatus comprising: an elongate female die of resilient elastomeric material, said female die comprising a longitudinal median portion dividing said die into opposite longitudinal halves, a first surface for contact with one side of said metal blank, an opposite surface and a pair of integral spaced longitudinal ribs at said opposite surface; said longitudinal median portion extending between and parallel to said ribs and said ribs merging with said longitudinal median portion at said opposite side in a smoothly radiused manner; and a male die shaped to conform to the inside dimension of the angle for pressing against the opposite side of said metal blank; wherein said longitudinal median portion constitutes hinge means for allowing said opposite halves of said female die, and therewith said longitudinal ribs, to hinge in opposite directions about said longitudinal median portion, in response to the pressure of said male die and to conform to the outside dimensions of the angle as sidewalls for said female die.

Claim 7

A method for press forming at least one angle in a flat metal blank comprising interposing the metal blank between a male die shaped to conform to an inside dimension of the angle and a female die of resilient elastomeric material bendable along a longitudinal line corresponding to an apex of the angle and having at least one longitudinal reinforcing rib on each of opposite longitudinal halves thereof at opposite sides of the line at a surface of said female die facing away from the metal blank; and pressing the male die towards the female die to press the blank therebetween and thereby causing the opposite longitudinal halves of said female die to hinge, with said ribs, in opposite directions about the longitudinal line and to conform to the outside dimensions of the angle as sidewalls for the female die, the female die being deformed at the area of the longitudinal line without substantial deformation of the opposite longitudinal halves; whereby metal of the metal blank at least partially flows around the angle in response to action between the dies.

Claim 8

A method for press forming at least one angle in a flat metal blank comprising interposing the metal blank between a male die shaped to conform to an inside dimension of the angle and a female die of resilient elastomeric material bendable along a longitudinal line corresponding to an apex of the angle and having at least one longitudinal reinforcing rib on each of opposite longitudinal halves thereof at opposite sides of the line at a surface of said female die facing away from the metal blank; and pressing the male die towards the female die to press the blank therebetween and thereby causing the opposite longitudinal halves of said female die to hinge, with said ribs, in opposite directions about the longitudinal line and to conform to the outside dimensions of the angle as sidewalls for the female die, the female die being deformed at the area of the longitudinal line without substantial deformation of the opposite longitudinal halves; whereby metal of the metal blank at least partially flows around the angle in response to action between the dies.