| 摘要 |
PROBLEM TO BE SOLVED: To prevent airleakage from a punch head without bringing erroneous motion of a stripmis detection mechanism. SOLUTION: A slit 25 is formed in the vertically splitting direction of a screw hole 29 formed in the central part of the upper face in a punch head 27 screwed in the upper end of a punch body 9. A cylindrical seal member 49 made of a conductive raw material is resiliently fitted along the screw hole 29 from the upper face of the punch head 27 to the downward side in the slit, and the upper part of the seal member 49 is projected out of the upper face of the punch head 27. When a striker comes into contact with the upper die on pressing, a fluid flows from an air pass to a connection port 39 of the upper face of the punch body 9 through the screw hole 29. Since the slit 25 provided in the screw hole 29 is airtightly closed by the seal member 49, the fluid is prevented from leaking. Even if the seal member 49 is caught between the striker and the punch head 27, as the seal member 49 is made of a conductive material, a malfunction caused by the stripmis detection device can be prevented.
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