| 摘要 |
A die assembly for mounting in a die press operates to punch a row of holes in a stack of paper sheets in response to a single press stroke. The die assembly comprises a stationary lower die block having a row of die holes therethrough, one or more lubricated stationary guide plates each having a row of guide holes therethrough and located above and spaced from the die block by a separator plate so as to define a stack-receiving slot, a reciprocably movable punch retainer assembly located above the guide plate and a row of elongated, downwardly-depending punches connected at their head ends to the punch retainer assembly which extend through and slidably engage the guide holes. When the press closes, the cutting ends of the punches move through the stack-receiving slot and through a stack of sheets therein into sliding engagement with the die holes. When the press opens, the punches are withdrawn clear of the stack-receiving slot. The head end of each punch is connected to the punch retainer assembly so that it can "float" (i.e. shift axially and/or shift transversely for very small distances). The "float" enables the guide holes in the guide plate(s) to maintain the cutter end so the punches in precise alignment with the die holes. The head end of each punch is also connected to the punch retainer assembly so as to prevent the punches from being axially disengaged from the punch retainer assembly during press operation and from rotating relative to the punch retainer assembly. The cutting end of each punch has a pair of spaced apart cutting edges separated by an indented surface which bears against the stack during a cutting operation.
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