Patent ID: 9676020
Date: 2017-06-13
CPC Classifications: B21D,Y10T

Claim:
1. A fine blanking device for blanking a sheet stock, comprising: a punch having cutting edges; a mother die module having a first die cavity defined by a first sidewall; a blank-holder module having a second die cavity defined by a second sidewall, both the first and second die cavities allowing the punch to enter therein; and a die holder with a cavity defined by a third sidewall, wherein a first trough structure is formed, surrounding the second die cavity, on the blank-holder module at a sheet stock contacting side thereof, thereby increasing a pressure exerted on the sheet stock by the blank-holder module at the area around the cutting edges of the punch when the blank-holder module presses on the sheet stock and the punch cuts the sheet stock, the first trough being recessed, away from the mother die module, from said sheet stock contacting side of the blank-holder module, and extending, in a radial direction extending from a central axis of the punch, from a position distanced from the second sidewall of the second die cavity to an outer sidewall of the blank-holder module, and wherein the cavity of the die holder accommodates the blank-holder module and the mother die module with the third sidewall directly contacting the outer sidewall of the blank-holder module and an outer sidewall of the mother die module, and the third sidewall continuously extends from the blank-holder module to a point beyond the sheet stock contacting side of the blank-holder module in a direction toward the mother die module, thereby enclosing the first trough structure.