Tab cutting

摘要

Cross cuts for forming the ends of a tab on a sheet, for example a glue tab on a corrugated paperboard container blank, are performed by independent rotary cutter units. Each cutter unit has a spirally convoluted blade which, as it rotates, cuts progressively inwards from an outside edge of the sheet towards an opposite outside edge. As the sheet is conveyed along, a downstream cutter unit cuts the leading end of the tab, and an upstream cutter unit cuts the trailing end. After each cut, the cutter remains at rest with its blade in an inoperative position out of the path of any oncoming sheet. A sensor senses the next oncoming sheet and initiates the cutting via a computer. These rotary cutters mitigate skewing of the sheets while being cut.