Unit for forming a plate element for manufacturing folding boxes

A forming unit for continuous production of folding boxes from a plurality of plate elements, wherein the plurality of plate elements are successively inserted into the forming unit and move in a feed direction, the forming unit comprising:

• a first slotter unit and a second slotter unit, each provided with pairs of rotating cylindrical shafts carrying respective forming tools which perform slitting, creasing, and cutting operations to form a plate element among the plurality of plate elements, and
• a cutting unit in which the pairs of rotating cylindrical shafts and the cutting unit work together to create, in the formed plate element, front and rear juxtaposed folding box layers,
• wherein a first two pairs of shafts among the pairs of rotating cylindrical shafts of the first slotter unit are configured to work together to provide central slits in each plate element aligned on a central transverse axis of the plate element, and a second two pairs of shafts, different from the first two pairs of shafts, among the pairs of rotating cylindrical shafts of the second slotter unit are configured to work together to respectively create rear edge slits in the rear layer and front edge slits in the front layer,
• wherein each pair of shafts of the first two pairs of shafts and of the second two pairs of shafts carries only one slitting tool fixed to a tool shaft of the corresponding pair of shafts
• wherein an angular position of a first tool shaft of one of the first two pairs of shafts and the second two pairs of shafts is adjustable automatically by a position variator, with respect to a second tool shaft of one of the first two pairs of shafts and the second two pairs of shafts, without adjusting an angular position of the slitting tool of the first tool shaft relative to the first tool shaft, to change a length of a central slit or a distance between a central slit and one of a rear edge slit and a front edge slit, and
• wherein the first slotter unit is arranged upstream of the second slotter unit in the feed direction and is configured to provide the central slits before the second slotter unit creates the rear edge slits and the front edge slits.