| 摘要 |
<p>A puncher is provided to secure a long life, ensure sufficient pressing force onto a workpiece, and install a hole at a position on the metal plate surface nearer than a corner part of the workpiece relative to a workpiece in which adjacent metal plate surfaces form an angle of 90 to 95 degrees. In a puncher(P) comprising: a cylindrical cover(1) having an opening hole formed in one end; a piercing punch(2) of which a front end face is projected from the one-end opening hole of the one end, and which is loosely inserted with respect to the cover such that the piercing punch is not removable; a cylindrical stripper(3) installed between the cover and the piercing punch in a state that the stripper is retained; and a biasing unit(4) by which the stripper is projected more than the piercing punch from the one-end opening hole, the front end face of the piercing punch being projected from a through-hole formed at a projecting end of the stripper by pressing onto the stripper against biasing force of the biasing unit, the puncher is characterized in that the cover is made of metal, and the one-end opening hole and an one cover portion(1b) near the one-end opening hole have a diameter smaller than that of the other cover portion(1a). The biasing unit is a compression coil spring(40).</p> |
