Interfolding machine

A method for producing stacks of interfolded sheets starting from a web of paper comprising:

• feeding of said web of paper along a predetermined feeding direction;
• cutting of said web of paper in a plurality of sheets of predetermined length;
• folding by a first and a second folding rollers counter-rotating one with respect to the other said sheets at a folding zone to form said stack of interfolded sheets interfolded according to a predetermined interfolding configuration;
• wherein:
• said cutting of said web into said sheets is carried out on a cutting roller configured to alternately distribute said plurality of sheets to said first folding roller forming a first plurality of sheets arranged to reach said folding zone through a first feeding path, and to a transfer roller of transfer section forming a second plurality of sheets arranged to reach said folding zone through a second feeding path, said transfer roller being configured to transfer said second plurality of sheets to said second folding roller, said transfer roller is provided with third holding elements arranged to hold said second plurality of sheets on a respective portion of the external surface of said transfer roller to transfer said second plurality of sheets from said cutting roller to said second folding roller, and in that said cutting roller is provided with:
• first holding elements configured to hold said sheets on a first portion of said external surface of said cutting roller;
• and
• second holding elements configured to hold said sheets on a second portion of said external surface of said cutting roller positioned downstream of said first portion, in such a way that, when said second holding elements are arranged to hold said sheets on said second portion, a sheet of said plurality is transferred from said cutting roller to said transfer roller, whilst, when said second holding elements are not arranged to hold said sheets on said second portion, a sheet is transferred from said cutting roller to said first folding roller;
• and
• deactivating said third holding elements of said transfer roller in such a way that all the sheets of said plurality of sheets are arranged to move from said cutting roller to said first folding roller reaching said folding zone through said first feeding path.

An interfolding machine for producing stacks of interfolded sheets starting from a web of paper, said machine comprising:

• a feeding section configured to cause said web of paper to move along a predetermined feeding direction;
• a cutting section comprising a cutting roller having an external surface, and a counter-cutting element configured to cooperate with each other in such a way to cut said web of paper in a plurality of sheets of predetermined length;
• a folding section comprising a first and a second folding roller counter-rotating one with respect to the other, said first and second folding rollers being configured to fold, at a folding zone, said plurality of sheets in a plurality of panels and to form said stack of interfolded sheets according to a predetermined interfolding configuration;
• and
• a transfer roller configured to alternatively move between:
• a working configuration, in which said cutting roller is arranged to alternately distribute said plurality of sheets to said first folding roller forming a first plurality of sheets arranged to reach said folding zone through a first feeding path, and to said transfer roller forming a second plurality of sheets arranged to reach said folding zone through a second feeding path, said transfer roller being configured to transfer said second plurality of sheets to said second folding roller, and
• a rest configuration, in which said transfer roller is not arranged to hold said sheets whereby all the sheets of said plurality of sheets are arranged to move from said cutting roller to said first folding roller and therefore to reach said folding zone through said first feeding path only;
• and
• said transfer roller is provided with third holding elements configured to hold said sheets on a portion of the respective external surface of said transfer roller, said third holding elements being configured to move between:
• an activation configuration, in which are arranged to hold said sheets whereby said transfer roller is arranged in said working configuration, and
• a deactivation configuration, in which said third holding elements are not arranged to hold said sheets and, therefore, said transfer roller is arranged in said rest configuration.