A method for forming individual zigzag folded piles from an endless web made from a flexible material such as paper and containing flaps defined by transverse perforation lines, in a pile forming machine comprising a pile support table and, above said table, a web guiding swinging unit making a pivoting movement above said table, said method comprising the steps of
- continuously feeding said endless web to said swinging unit and causing said unit to deposit the continuously forward-moving web on said table in a zigzag folded file configuration,
- rupturing the web along a transverse perforation line between the last flap of the folded pile and the first flap of a new pile to be formed,
- continuing the forward motion of the ruptured web until the last flap has been laid down on the folded pile and a forward end of the first flap reaches a position corresponding to its final position at the base of the new pile to be formed,
- stopping the swinging device and the forward motion of the web,
- moving said support table away from a pile-forming position to a distant pile discharge position,
- providing a cushion of gaseous fluid such as air under pressure in a zone located below said forward edge of said first flap,
- causing said cushion to support said forward edge zone and to form a temporary support during the absence of the supporting table,
- moving said supporting table back to its pile-forming position after the discharge of the completed pile so that said forward edge zone contacts said supporting table,
- stopping the formation of said gaseous fluid cushion under said forward edge zone of said first flap and restarting the operation of the swinging unit and the forward motion of said web.