| 摘要 |
A punch assembly for punching a workpiece comprising a unitary stripper spring assembly that can be adjustably fastened to a punch. The unitary stripper spring assembly includes a threaded head which engages a threaded end of the punch so the effective length of the punch can be varied after sharpening by simply turning the unitary stripper spring assembly relative to the punch. The punch is fastened to the unitary stripper spring assembly only at the head. The unitary stripper spring assembly further includes a washer, and a telescopic retainer enclosed in a stripper spring between the head and the washer. The telescopic retainer responds to the force exerted on the punch assembly by the ram of a punching device by contracting during the punching stroke. After the punching stroke the stripper spring expands to strip the punch from the workpiece and the stripper spring assembly returns to its normal position. The unitary stripper spring assembly forms a discrete and integral mechanism independent of the punch. The punch assembly of the present invention achieves a simple one step adjustment of the effective punch length without the use of special tools or any disassembly of the unitary stripper spring assembly, even after repeated sharpening of the punch. Also, a punch guide having a retainer device for attaching the punch guide to the punch forms part of the present invention.
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