A method for separating two successive stacks of interfolded sheets of a type joined by a pre-tear or perforation line and for obtaining a pack of interfolded sheets wherein an end sheet of the pack is partially folded on itself to define a grippable flap for a facilitated extraction of the sheets from the pack, comprising:
- predisposing a pair of support tables movable independently of one another;
- predisposing a separating board, movable independently of the pair of support tables;
- predisposing a pair of separator elements arranged facing one another and movable independently of one another and independently of the pair of support tables and of the separating table;
- and comprising carrying out steps of:
- positioning the pair of support tables in a raised position facing one another, and in a configuration neared one another, transversally to a vertical direction along which the folding of interfolded sheets joined by a pre-tear or perforation line takes place in order to form stacks of interfolded sheets, for supporting the folded and interfolded sheets during the formation of a stack;
- translating the pair of support tables vertically downwards to enable complete formation of a stack of interfolded sheets of a predetermined height;
- positioning the pair of separator elements in a position in which they are splayed and are bilateral to the vertical direction at the sides of the stack of interfolded sheets during the formation and completion of the stack on the pair of support tables;
- positioning the separating board in a lateral position with respect to the vertical direction along which the formation and completion of the stack of the interfolded sheets on the pair of support tables takes place;
- having completed the formation of a stack of interfolded sheets of a predetermined height:
- moving the pair of separator elements transversally to the vertical direction so as to bring them into a position in which they are mutually neared in such a way as to insert the separator elements between consecutive connecting sheets between the folded sheet of the already-formed stack and a first folded sheet of a successive stack under formation in order to support the successive stack under formation, then lowering the pair of support tables so as to move the already-formed stack away from the successive stack under formation supported by the pair of separator elements, unfolding a series of connecting sheets between the last sheet of the already-formed stack and the first sheet of the successive stack under formation;
- moving the separating board transversally to the vertical direction in order to position the separating board above the already-formed stack supported by the pair of support tables;
- translating the pair of support tables and the separating board vertically downwards so as to move the already-formed stack away from the successive stack under formation in such a way as to separate the connecting sheets between the two stacks at a pre-tear or perforation line present thereon leaving a strip of sheets hanging below the stack under formation on the pair of separator elements;
- moving the separating board away from the formed stack;
- moving the pair of support tables away from one another so as to position the support tables in a reciprocally moved-away position in order to release the stack formed above a conveyor;
- moving a first support table of the pair of support tables upwards into a lower position than the pair of separator elements and moving the first support table transversally to the vertical direction to abut the strip of hanging sheets and to fold a first portion of the strip of hanging sheets below the successive stack under formation on the pair of separator elements leaving a second portion of the strip of sheets hanging below the first support table;
- moving a second support table of the pair of support tables upwards into a lower position than the pair of separator elements and moving the second support table transversally to the vertical direction to abut the second portion of the strip of hanging sheets to partially fold the second portion below the first support table leaving an end flap of the second portion partially folded and hanging below the second support table;
- moving the first support table and the second support table in order to arrange them facing one another and in the configuration neared one another;
- raising the first support table and the second support table in order to arrange them against the successive stack under formation on the pair of separator elements leaving the end flap partially folded and hanging between the first support table and second support table;
- moving the pair of separator elements away from one another in order to disengage the successive stack under formation and so as to release the successive stack under formation to rest on the first support table and on the second support table;
- translating the first support table and the second support table vertically downwards up to complete formation of the successive stack obtaining a pack of interfolded sheets with the end flap partially folded and hanging there-between and remaining projecting below the pack to define a grippable flap for a facilitated extraction of the sheets from the pack.