System and a method for stacking a fanfolded continuous web of sheet material

A method of stacking a sheet material, said method comprising the steps of:

• providing a feeding device for feeding a continuous web (M) in a longitudinal direction (L);
• providing a creasing device (2) downstream of said feeding device to form transverse creases (C) on the continuous web (M) spaced apart at a constant longitudinal pitch (K) and to define adjacent partitions (P);
• providing a folding device (14) located downstream of the creasing device (2) for progressively and alternately fanfolding the adjacent partitions (P) along the creases (C);
• providing a collection device (39) downstream of the folding device (14) for collecting the folded web (M) and forming a stack of superimposed adjacent partitions (P);
• providing a vertically-extending column (40) in the collection device (39) for retaining the stack of superimposed adjacent partitions (P);
• providing in said collection device (39) a first stack-supporting rack (44) and a second stack-supporting rack (45), a stack unloading unit (46), and a dynamic cutting unit (52) for cutting at least one adjacent partition (P) of the stack;
• moving said first supporting rack (44) and said second supporting rack (45) horizontally toward the stack and vertically toward the unloading unit (46), thereby tracking a formation of the stack without stopping the folding device (14);
• actuating the dynamic cutting unit (52) on the fly and causing the dynamic cutting unit (52) to interact with an uppermost adjacent partition (P) in the stack, thereby avoiding a need to stop the folding device (14);
• and
• depositing the stack in the unloading unit (46).