摘要 |
A method of imparting directional permanency of folding to a sheet, and an apparatus therefor, which is suitable for manufacturing frame bodies, cushioning members and other block products for packaging, from a sheet of paper and other recyclable materials. The method includes a step of moving respective folding working tools, disposed on one or both surfaces of a sheet, required amounts so as to fold the sheet along respective folding ruled lines, and a step of shortening spacings between the respective folding working tools in a uniform ratio in accordance with an apparent amount of shortening in a longitudinal dimension caused by the shifting, while synchronizing with the moving step. Directional permanency of folding can be accurately imparted to the sheet along the folding ruled lines.
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