Puncher

Abstract

In a puncher, with respect to a cylindrical cover with a one-end opening hole, a piercing punch is loosely but not movably inserted. A tip end surface of the piercing punch is protruded out from the one-end opening hole of the cover. A cylindrical stripper provided between the cover and the piercing punch is provided detachably from the one-end opening hole. By a biasing member, the stripper is protruded out from the one-end opening hole more than the piercing punch does. When the stripper is pressed in against biasing force of the biasing member, the tip end surface of the piercing punch becomes to protrude out from a through-hole formed at a protruding end of the stripper. A removal-prevention member which prevents the stripper from removing from the cover is provided detachably with respect to the cover.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a puncher for piercing a workpiece with a piercing punch while a stripper is pressing the workpiece.BACKGROUND OF THE INVENTION[0002]A conventional piercing puncher is disclosed, for example, in Japanese Patent Application Laid Open No. 2006-61938 (refer to FIG. 3).[0003]This puncher 9 is illustrated in FIG. 17 and includes a cylindrical cover 90 with a one-end opening hole 90a, a piercing punch 91a tip end of which is protruded from the one-end opening hole 90a and which is loosely but not movably inserted with respect to the cover 90 by means of a punch retainer 94, and a cylindrical stripper 92 provided between the cover 90 and the piercing punch 91 in a retaining state, and the stripper 92 is protruded more than the piercing punch 91 is from the one-end opening hole 90a by a compression coil spring 93 (biasing means). When the stripper 92 is pressed in and down against biasing force of the compression coil spring 93, a...

AI Technical Summary

Benefits of technology

[0013]It is another object of the present invention is to provide a puncher which has a long lifetime, can guarantee sufficient pressing force onto a workpiece, and punch a hole at a position near a corner of a workpiece where adjacent metal plate surfaces form a corner with an angle of from 90 degrees to 95 degrees.

[0018]In the puncher of the present invention, after the removal-prevention member and then the stripper are removed from the cover, the tip portion of the pierce punch protrudes out from the cover, which allows to facilitate the positioning of the piercing punch.

[0025]The puncher according to the present invention is usable both for a numeral value inputting method and a visual positioning method. The puncher can also provide a long lifetime, guarantee sufficient pressing force onto a workpiece, and punch a hole at a position near a corner of a workpiece having adjacent metal plate surfaces forming an angle of from 90 degrees to 95 degrees at the corner.

Problems solved by technology

However, providing the above two types of punches leads not only to a higher cost but also a need of maintenance thereof.

And the foregoing puncher 9 has a problem that it is difficult to punch a hole at a position near a corner of the workpiece where adjacent metal plate surfaces form the corner with an angle of from 90 degrees to 95 degrees (in many cases, from 90 degrees to 93 degrees, which holds true hereinafter).

However, this reduces elastic resilient force of the compression coil spring 93 within the cover 90 and then would cause another problem that a pressing force onto a predetermined workpiece cannot be guaranteed.

However, this will extremely shorten a lifetime of the cover 90.

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