Blank and draw apparatus with gap control

Abstract

Apparatus for drawing, or blanking and drawing, a flat metallic piece into a cup shape. A blanking punch, blanking die, draw die, movable stripper and a spacer are mounted on the stationary bed of a press. A pressure pad and draw punch are carried by the ram of a press. The pressure pad is positioned to contact first the blanking punch, then to contact the movable stripper and push it solidly against the spacer. As the ram continues its downward movement, the pressure pad collapses with respect to the ram by virtue of its connection to a piston operating in a cylinder in the ram containing controllable air pressure. The maintenance of a predetermined pressure pad-draw die gap during the draw prevents wrinkling, and the maintenance of the controlled pressure on the pressure pad prevents thinning and subsequent clipping of ears. The edge of the blank which is captured between the pressure pad and draw die is gradually pulled radially inward as the die approaches the bottom of its stroke and the wrinkling and thinning and clipping of ears of the blank which would take place during this pulling is prevented. On the upstroke of the ram air is injected into the draw punch to assist in stripping the finished cup from the punch, and the blanking punch and mounting plate are raised by springs, and the movable stripper raises the scrap upward for removal.