| 摘要 |
<p>In order to achieve speed up of the piercing operation to form elongated forms in a thin sheet whose length is greater than the thickness and width thereof, a piercing apparatus is provided with an upper roller die (3) having a first cutter roller (18) held between press rollers (16,17) so that the first cutter roller (18) protrudes at the outer peripheral portion thereof, from the outer peripheral surfaces of the press rollers (16,17), a lower roller die (4) having recesses between two second cutter rollers (29,31) and engaging with the outer peripheral portion of the first cutter roller. The thin sheet (2) is continuously fed in the lengthwise direction thereof into the engagement portion between the upper and lower dies. When a sliding cutter is engaged in the recesses formed on the first cutter roller, the thin sheet passing through the engagement portion is cut to form elongated holes. <IMAGE></p> |
