Patent ID: 7891226

Claim:
Apparatus for forming an article from a blank of sheet metal comprising: a first die member having a cavity formed therein; a second die member; means for imparting relative reciprocal movement between the first die member and the second die member to deform the blank of sheet metal within the cavity of the first die member; means for producing a magnetic field to exert magnetic restraining forces on the blank of sheet metal to selectively restrain relative movement between the blank of sheet metal and the first die member during the deformation of the blank of sheet metal, wherein the means for producing a magnetic field includes a plurality of electromagnets; and means for controlling the strength of the magnetic field to vary the magnetic restraining forces during the deformation of the blank of sheet metal, wherein the means for controlling the strength of the magnetic field includes a microprocessor for controlling the strength of the magnetic field produced by each of the electromagnets to provide different magnetic restraining forces at selected locations of the blank of sheet metal during the deformation of the blank of sheet metal.