Patent ID: 6539766
Filing Date: 2003-04-01
Classification: B21D

Abstract:
A negative-angle forming die, comprising:a lower die half having a supporting portion for placing a sheet metal work; an upper die half to be lowered straightly downward onto the lower die half for forming the work; an intrusion forming portion formed in the lower die half at an edge portion near the supporting portion; a rotary cam rotatably provided in the lower die half; a slide cam including an intrusion forming portion and slidably opposed to the rotary cam; and an automatic retractor provided in the lower die half for pivoting the rotary cam to a position allowing the work to be taken out of the lower die half after a forming operation, the work placed on the supporting portion of the lower die half being formed by an intrusion forming portion of the rotary cam and the intrusion forming portion of the slide cam, the slide cam forming the work by sliding, and the automatic retractor pivoting back the rotary cam after the forming operation for allowing the work to be taken out of the lower die half, wherein a flange is formed at an end portion of the work in a direction across an axis of the pivoting, the work then undergoing an intrusion formation, the flange at the end portion of the work being protected from damage caused by retraction of the rotary cam, the rotary cam being divided into an end rotary cam for placing the flange formed at the end portion of the work and a main rotary cam for the other portion, both the end rotary cam and the main rotary cam being disposed on a same axis of pivoting, the end rotary cam not being pivoted for an initial predetermined period of the retraction, and thereafter the end rotary cam being moved axially toward the main rotary cam.