| US 7,546,757 B2 | ||
| Method of working small recess portion | ||
| Hideyuki Ogawa, Nagano (Japan); Koichi Saito, Nagano (Japan); Nagamitsu Takashima, Nagano (Japan); and Katsunori Ono, Nagano (Japan) | ||
| Assigned to Seiko Epson Corporation, Tokyo (Japan) | ||
| Filed on Sep. 14, 2005, as Appl. No. 11/225,052. | ||
| Claims priority of application No. P2004-266322 (JP), filed on Sep. 14, 2004. | ||
| Prior Publication US 2006/0055732 A1, Mar. 16, 2006 | ||
| Int. Cl. B21D 31/02 (2006.01); B21D 17/02 (2006.01) | ||
| U.S. Cl. 72—325 [72/414; 72/379.6] | 4 Claims |
| 1. A metal plate working method comprising the steps of:
pressing a first die onto a metal plate for press-forming a recess groove portion extending along and being spaced apart from
an imaginary line, the recess groove portion defining a first portion and a second portion that is adjacent to the first portion
along the imaginary line and that is higher in rigidity than the first portion;
pressing a second die onto the metal plate for press-forming recess portion ends of which are aligned on the imaginary line,
the second die having a predetermined number of male die pieces so that:
the male die pieces are arranged in a row along the imaginary line;
ends of some male die pieces are located on the imaginary line, and face the first portion; and
ends of some other male die pieces are located on the imaginary line, and face the second portion,
wherein the recess groove portion has a bottom partially formed with a through hole, the first portion corresponds to a first
part of the recess groove portion which has the bottom formed with the through hole, and the second portion corresponds to
a second part of the recess groove portion.
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