A SEPARATION UNIT FOR A MACHINE FOR PRODUCING FLAT PRODUCTS MADE OF PAPER, IN PARTICULAR STACKS OF NAPKINS, TISSUES, OR SIMILAR PRODUCTS AND METHOD FOR PRODUCING SUCH PRODUCTS DESCRIPTION

Field of the invention

The present invention relates to the technical field of the machines for producing consumer products, in particular flat products made of paper, such as stacks of napkins, tissues, and similar products.

The invention also relates to a method for producing such flat products.

Background of the invention

As it is known, the machines for producing consumer products made of paper such as packages of napkins, packages of tissues, and similar products, provide the advancement of a continuous web of paper, which is normally unwound from a roll having a large diameter, along a displacement direction. Along the aforementioned displacement direction, the continuous web of paper is, normally, folded at a folding station according to a longitudinal line. The folding station provides a folding member, normally substantially triangular-shaped, on which the web of paper is caused to advance to be, then, fed between two vertical feeding rollers and, therefore, to a couple of counter-rotating folding rollers having vertical axes. The folding rollers are positioned one close to the other in such a way to define a passage for the continuous web of paper and are provided with folding members, which, when the web of paper passes through the aforementioned passage between the folding rollers, fold the web of paper along a direction orthogonal to the aforementioned longitudinal folding line. Normally, the folding members provide on each folding roller a gripper configured in such a way to grip the web of paper along a folding line. In some cases, the introduction of the web of paper into the folding member is caused by blades, or wedges, also these mounted on the folding rollers, but at staggered positions with respect to the grippers. More precisely, in order to make a fold on the web of paper, at the aforementioned passage defined between two folding rollers, a gripper of a folding roller and a folding blade of the other folding roller are alternately positioned. More in detail, the folding of the web of paper occurs because the folding blade of a folding roller pushes the web of paper into the gripper of the other folding roller. Therefore, the web of paper, alternatively, adheres, at first, to one folding roller and, then, to the other folding roller, whereby downstream of the folding rollers, the web of paper is zig-zag folded. Since, normally, a folding roller is provided with a folding blade and a gripper, at each complete turn of a folding roller about its rotation axis, at least two folds are made on the web of paper. Downstream of the folding rollers a separation unit is provided configured to separate the stack of zigzag folded panels into a predetermined number of groups each of which containing a number of panels equal to the number of napkins, or tissues, which will form a final stack.

In particular, separation unit for machines for producing packages of tissues, napkins, and similar products exist that provide to move the separation fingers along a predetermined path. Normally, the aforementioned path has two rectilinear sections, one of gone and one of return, which run parallel to the direction of formation of the stack of folded panels, but along which the separation fingers are moved according to opposite directions and two connection sections for connecting the rectilinear sections in such a way to form a closed path. Among the different proposed solutions, some provide curvilinear connection sections, some others, instead, rectilinear connection sections that are transversal to the aforementioned gone and return sections. In the case of curvilinear connection sections, often, during the introduction of the separation fingers into the stack of panels a the end portions of some panels of the stack are crushed and, therefore, a loss of quality of the final product is caused.

An example of a separation unit which, instead, provides rectilinear connection sections is, for example, described in EP0294675. The separation unit described in this document provides to introduce and extract the separation fingers along directions orthogonal to the forming direction of the stack. More precisely, the separation fingers are maintained on different devices which move the same along the aforementioned path by a magnetic couple. More precisely, each separation finger is provided with a portion made of a ferromagnetic material and the displacement devices are provided with magnets arranged to attract by a magnetic attraction force the aforementioned separation finger at the portion made of a ferromagnetic material.

However, the solution described in EP0294675 is not highly reliable, because the magnetic engagement could be not effective and, therefore, not able to move a separation finger along the aforementioned displacement path thus obstructing the other separation fingers moved along the same path. This unavoidably compromises, not only the separation operation, but also all the operation that are carried out downstream of this operation, as for example the cut, and the packaging, until the production of the packages of tissues, or napkins. As for example described in EP0294675, normally, the separation fingers are introduced into the stack by means of pneumatic means and mechanical systems thus resulting inaccurate and discontinuous due to the delays and the slowness of the pneumatic systems. In particular, besides being difficult to manage the variability of the delay between the introduction order and the effective introduction of the separation fingers, the pneumatic systems are slow with respect to the dynamics requested by the plants with high productivity. For the aforementioned reasons, if pneumatic systems are used in the machines for producing packages of napkins, or tissues, a low quality of the final product is obtained.

Other examples of prior art machines having similar drawbacks are described in W002/12102 and EP2396250.

Summary of the invention

It is, therefore, an object of the present invention to provide a separation unit for machines for producing stacks of flat product, such as stacks of napkins, tissues and similar products that is able to overcome the aforementioned drawbacks of the prior art solutions.

It is, in particular, an object of the present invention to provide a separation unit that is able to considerably increase the quality of the final product and the productivity of the machines for producing flat products.

It is also an object of the present invention to provide a method for producing packages of flat products having analogous advantages.

It is also an object of the present invention to provide a separation finger for a separation unit for machines for producing stacks of flat product, such as stacks of napkins, tissues and similar products which allows of obtain the aforementioned advantages with respect to the prior art.

These and other objects are achieved by the separation unit for a machine for producing flat products made of paper, in particular stacks of napkins, tissues, or similar products, according to claim 1, said machine comprising a folding station configured to fold along a plurality of transversal folding lines a previously folded semi-finished product made of paper along a longitudinal line, in such a way to form a stack of zigzag folded panels, said separation unit being configured to separate said predetermined plurality of zigzag folded panels into a plurality of groups of zigzag folded panels, said separation unit comprising a first and a second separation group positioned at opposite sides with respect to said plurality of zigzag folded panels, each said first and second separation groups comprising: a displacement device configured to move a plurality of separation fingers along a first and a second displacement direction opposite one with respect to the other, in such a way that said plurality of separation fingers, along said first displacement direction is arranged externally to said stack of zigzag folded panels, and, instead, internally to said stack of zigzag folded panels along said second displacement direction; an introduction device comprising an introduction member configured to slide along an introduction direction orthogonal to said first and second displacement directions, said introduction device being arranged to cause a separation finger of said plurality of separation fingers at a time to move into said stack of zigzag folded panels; an extraction device configured to extract a separation finger at a time from said stack of zigzag folded panels, in particular at an extraction zone; whose main characteristic of the separation unit is that said introduction device, furthermore, comprises: a first actuation device configured to cause a separation finger at time to move from said first displacement direction to said introduction direction; a second actuation device configured to cause said introduction member to slide along said introduction direction; and that said first and said second actuation device comprises, respectively, a first and a second linear electric motor.

Other features of the present invention and related embodiments are set out in the dependent claims.

According to another aspect of the invention, a machine for producing flat products made of paper, in particular stacks of napkins, tissues, or similar products, comprises: a feeding station configured to feed at least a web of paper along a first predetermined feeding direction; a first folding station equipped with a first folding group configured to fold said web of paper in such a way to obtain a folded web of paper provided with at least a longitudinal folding line; a second folding station positioned downstream of said first folding station and configured to fold said folded web of paper along a plurality of transversal folding lines, said second folding station being configured to make a plurality of transversal folding lines on said folded web of paper in such a way to obtain a stack of zigzag folded panels; a cutting station equipped with a cutting member configured to cut said stack of zigzag folded panels along a cutting direction, in such a way to obtain a first and a second package of flat products; whose main characteristic is to provide a separation station as described above and positioned between said second folding station and said cutting station.

According to a further aspect of the invention, a separation finger for a separation unit of a machine for producing flat products made of paper, in particular stacks of napkins, tissues, or similar products comprises a main body provided with a portion protruding from a first side of said main body, said main body being, furthermore, provided with a recessed portion at a second side opposite to the first side, said separation finger being, furthermore, provided with a separation portion protruding from a third side and configured to be positioned, in use, between two successive panels of a stack of zigzag folded panels being formed.

According to still a further aspect of the invention a method for separating a stack of zigzag folded panels by a separation unit of a machine for producing flat products made of paper, in particular stacks of napkins, tissues, or similar products, said machine comprising a folding station configured to fold along a plurality of transversal folding lines a semi-finished product of paper previously folded along a longitudinal line, in such a way to form a stack of zigzag folded panels, said separation unit being configured to separate said predetermined plurality of zigzag folded panels into a plurality of groups of zigzag folded panels, said separation unit comprising a first and a second separation group positioned at opposite sides with respect to said plurality of zigzag folded panels, each said first and second separation group comprising the steps of: moving a plurality of separation fingers along a first and a second displacement direction opposite one with respect to the other, in such a way that said plurality of separation fingers, along said first displacement direction is arranged externally to said stack of zigzag folded panels, and, instead, internally to said stack of zigzag folded panels along said second displacement direction; introducing a separation finger of said plurality of separation fingers at a time into a stack of zigzag folded panels, said introducing step being carried out by an introduction member arranged to slide along an introduction direction orthogonal to said first and said second displacement direction; extracting a separation finger at a time from said stack of zigzag folded panels at an extraction zone; whose main characteristic is that the introducing step provides the steps of: moving a separation finger at a time from said first displacement direction to said introduction direction; sliding of said introduction member along said introduction direction; and that said moving step and said sliding step are carried out respectively from a first and a second linear electric motor.

According to a further alternative embodiment of the invention, a separation unit for a machine for producing flat products made of paper, in particular stacks of napkins, tissues, or similar products, said machine comprising a folding station configured to fold along a plurality of transversal folding lines a semi-finished product of paper previously folded along a longitudinal line, in such a way to form a stack of zigzag folded panels, said separation unit being configured to separate said predetermined plurality of zigzag folded panels in a plurality of groups of zigzag folded panels, said separation unit comprising a first and a second separation group positioned at opposite sides with respect to said plurality of zigzag folded panels, each said first and second separation groups comprising: a displacement device configured to move a plurality of separation fingers along a first and a second displacement direction opposite one with respect to the other, in such a way that said plurality of separation fingers, along said first displacement direction is arranged externally to said stack of zigzag folded panels, and, instead, internally to said stack of zigzag folded panels along said second displacement direction; an introduction device comprising an introduction member configured to slide along an introduction direction orthogonal to said first and second displacement directions, said introduction device being arranged to cause the a separation finger at a time of said plurality of separation fingers to move into said stack of zigzag folded panels; an extraction device configured to extract a separation finger at a time from said stack of zigzag folded panels, in particular at an extraction zone; whose main characteristic is that said introduction device comprises, furthermore, a first engagement member configured to engage an engagement portion of a separation finger and to position said engaged separation finger on said introduction member, and that said introduction member comprises an additional first engagement member configured to engage by a shape coupling with an additional engagement portion of said respective separation finger positioned on the same.

According to still a further aspect of the invention, a method for separating a stack of zigzag folded panels by a separation unit of a machine for producing flat products made of paper, in particular stacks of napkins, tissues, or similar products, said machine comprising a folding station configured to fold along a plurality of transversal folding lines a semi-finished product of paper previously folded along a longitudinal line, in such a way to form a stack of zigzag folded panels, said separation unit being configured to separate said predetermined plurality of zigzag folded panels in a plurality of groups of zigzag folded panels, said separation unit comprising a first and a second separation group positioned at opposite sides with respect to said plurality of zigzag folded panels, each said first and second separation groups comprising the steps of: moving a plurality of separation fingers along a first and a second displacement direction opposite one with respect to the other, in such a way that said plurality of separation fingers, along said first displacement direction is arranged externally to said stack of zigzag folded panels, and, instead, internally to said stack of zigzag folded panels along said second displacement direction; introducing a separation finger of said plurality of separation fingers at a time in a stack of zigzag folded panels, said introducing step being carried out causing by an introduction member arranged to slide along an introduction direction orthogonal to said first and said second displacement directions; extracting a separation finger at a time from said stack of zigzag folded panels at an extraction zone; whose main characteristic is that the introducing step provides the steps of: engaging an engagement portion of a separation finger; positioning said separation finger engaged on said introduction member; engaging an additional engagement portion of said separation finger by a shape coupling with an additional first engagement member of said introduction member during said sliding along said introduction direction.

Brief description of the drawings

The invention will be now illustrated with the following description of an exemplary embodiment thereof, exemplifying but not limitative, with reference to the attached drawings wherein:

- Fig. 1A diagrammatically shows a side elevational partially sectioned view, a first embodiment of a separation unit, according to the invention, for a machine for producing stacks of flat products made of paper, in particular stacks of napkins;

- Fig. IB diagrammatically shows a side elevational partially sectioned view of a possible alternative embodiment of the separation unit of figure 1A;

- Figures 2 and 3 diagrammatically show a side elevational view, respectively, of the left separation group, and of the right separation group forming the separation unit of figure IB;

- Figures from 4A to 4C show, respectively, a side elevational plan view, and a side elevational perspective view of a separation finger according to the invention;

- Figures from 5A to 5F diagrammatically show a vista side elevational partially sectioned of a possible sequence of operations that can be carried out by the separation unit of figure 1A, or of figure IB;

- Fig. 6 diagrammatically shows a side elevational view partially sectioned of a possible alternative embodiment of the separation unit shown in the figures 5A-5F;

— Figures 7A and 7B diagrammatically show in a plan view the alternative embodiment of the separation unit shown in figure 6;

- Figures from 8A to 8C diagrammatically show a side elevational perspective view of some operations carried out by the introduction device provided by the separation unit, according to the invention;

- Fig. 9 diagrammatically shows a possible alternative embodiment of the introduction device of figures 8A-8C;

- Fig. 10 diagrammatically shows a plan view of still another embodiment of the separation unit, according to the invention;

- Fig. 11 diagrammatically shows a perspective view of a possible alternative embodiment according to the invention for the first and the second actuation devices.

Detailed description of some exemplary embodiments of the invention

With reference to figure 1A, the separation unit 1, according to the present invention, for machines for producing stacks of napkins, tissues, or similar products, of the type comprising a first and a second folding roller 201a and 201b comprising grip elements, for example grippers, cooperating with separation fingers 210a and 210b, to produce a plurality of transversal folds on a web previously folded along a longitudinal direction, in such a way to obtain a stack of zigzag folded panels 250, provides a first and a second separation group 100a and 100b positioned at opposite sides with respect to the aforementioned stack of zigzag folded panels 250. In particular, each separation group 100a, or 100b, provides a respective displacement device 10a, or 10b, configured to move a plurality of separation fingers 60 along a first displacement direction 101a, or 101b, and a second displacement direction 102a, or 102b opposite one with respect to the other. More precisely, the separation fingers 60, along the first displacement direction 101a, or 101b, are arranged externally to the stack of zigzag folded panels 250. Instead, along the second displacement direction 102a, or 102b, the separation fingers 60 are arranged internally to the stack of zigzag folded panels 250. Each separation group 100a and 100b comprises, furthermore, an introduction device 20a, or 20b, provided with an introduction member 21a, or 21b, configured to slide along an introduction direction 103a, or 103b, orthogonal to the aforementioned first and second displacement directions 101a, 101b, and 102a, 102b. In particular, each introduction device 20a, or 20b, is arranged to cause a separation finger 60 at a time to move, i.e. to be introduced, into the stack of zigzag folded panels 250.

Furthermore, each separation group 100a and 100b comprises an extraction device, diagrammatically shown in figure 1A with a block 120a and 120b, configured to extract a separation finger at a time from stack 250 of zigzag folded flat products once that the same reaches an extraction zone 135a, or 135b, positioned along the aforementioned second displacement directions 102a and 102b. In particular, the extraction of the separation finger 60 from stack 250 can be carried out by the extraction device 120a, or 120b, through a rotation, or a translation, or a combination of movements comprising at least a rotation and at least a translation.

According to the present invention, the introduction device 20a, or 20b comprises a first actuation device 80a, or 80b, configured to cause a separation finger 60 at a time to move from the first displacement direction 101a, or 101b, to the introduction direction 103a, or 103b. Advantageously, the introduction device 20a, or 20b, comprises, furthermore, a second actuation device 90a, or 90b, configured to cause the aforementioned sliding of the introduction member 20a, or 20b, along the aforementioned introduction direction 103a, or 103b. More in particular, the aforementioned first and second actuation devices 80a, 80b, and 90a, 90b, comprise, respectively, a first and a second linear electric motor.

In particular, the introduction device 20a, or 20b, comprises a first engagement member 25a, or 25b. More in particular, the first engagement member 25a, or 25b, is configured to move between a disengagement position of the separation fingers 60 and an engagement position of the same. More precisely, the first engagement member 25a, or 25b, is configured to engage an engagement portion 65 of a separation finger 60 and to position the same on the introduction member 21a, or 21b. More in particular, each introduction member 21a, or 21b, comprises a respective additional first engagement member 26a, or 26b. These are configured to engage by a shape coupling with an additional engagement portion 66 of the separation finger 60 when this is arranged, respectively, on the introduction member 21a, or 21b. According to a possible embodiment of the invention, the engagement member 26a, or 26b, of the introduction member 21a, or 21b, can be an engagement seat provided in the respective introduction member 21a, or 21b.

As diagrammatically shown, for example in the figures 8A-8C, each introduction device 20a, and 20b, furthermore, provides a push member 22a, or 22b, configured to move between a push configuration, in which is arranged to apply a push on the separation finger 60 arranged on the introduction member 21a, or 21b, to cause the same to move from the introduction member 21a, or 21b, to the displacement device 10a, or 10b, along the second displacement direction 102a, or 102b, and a rest configuration in which is not arranged to apply the aforementioned push.

More in particular, the push member 22a, or 22b, is arranged to apply, advantageously at a push surface 23a, or 23b, a push on the separation finger 60 arranged on the introduction member 21a, or 21b, such to cause the additional engagement portion 66 to be disengaged from the additional first engagement member 26a, or 26b, and to engage the same in the fourth engagement member 12a, or 12b.

In a particular embodiment of the invention, diagrammatically shown in figure IB, each extraction device 120a, or 120b, can comprise a respective extraction member 121a, or 121b, configured to slide along a extraction direction 104a, or 104b, opposite to the aforementioned introduction direction 103a, or 103b, for extracting a separation finger 60 at a time from the stack of zigzag folded panels 250. More in particular, each extraction member 121a, or 121b, can comprise a respective second additional engagement member 126a, or 126b (see figure 10) configured to engage by a shape coupling with the additional engagement portion 66 of the separation finger 60 when this is arranged on the extraction member 121a, or 121b. Furthermore, each extraction device 120a, or 120b, can comprise, a second engagement member 125a, or 125b. More in particular, the second engagement member 125a, or 125b, is configured to move between a disengagement position of the separation fingers 60 and an engagement position of the same. More precisely, the second engagement member 125a, or 125b, is configured to engage the engagement portion 65 of a separation finger 60 and to position the same on the extraction member 121a, or 121b.

According to an embodiment and diagrammatically shown in the figures 4A and 4C, each separation finger 60 has a main body 62 provided with a separation portion 63 arranged, in use, to be positioned between two adjacent panels of a stack of zigzag folded panels. Advantageously, the separation portion 63 is arranged to be positioned at an aperture 205a, or 205b, of the folding rollers 201a, or 201b, depending on if the separation finger is a finger positioned on the separation group 100a, or on the second separation group 100b, before being moved along the displacement direction 102a, or 102b (see figure 1A and IB). Furthermore, according to the present invention, each separation finger 60 provides an engagement portion 65, advantageously a recessed portion, at a first side of the aforementioned main body 62, and an additional engagement portion 66, advantageously a protruding portion, at a second side of the main body 62 that is opposite to the first side.

Preferably, each displacement device 10a and 10b is provided with a third engagement member 11a and lib configured to engage the aforementioned additional engagement portion 66 of the separation fingers 60 when these are positioned along the first displacement direction 101a, or 101b, and a fourth engagement member 12a and 12b, also these configured to engage the aforementioned additional engagement portion 66 of the separation fingers 60, when these are positioned along the second displacement direction 102a and 102b. More in detail, each displacement device 10a and 10b is, advantageously, provided with a first longitudinal groove 11a and lib which extends along the aforementioned first displacement direction 101a and 101b. Analogously, the fourth engagement member 12a, or 12b, of the displacement device 10a, or 10b, provides a second longitudinal groove, which extends along the aforementioned second displacement direction 102a and 102b. In this way it is possible to move the separation fingers 60 along the first and second displacement directions 101a, 101b, 102a, 102b, accurately and at the same time quickly.

In particular, as diagrammatically shown in the figures from 5A to 5F, each displacement device 10a and 10b provides a guide member 15a and 15b provided with the aforementioned longitudinal grooves 11a, lib and 12a and 12b, and a motion transmission device 16a and 16b, for example a transmission belt, advantageously positioned at the respective longitudinal groove 11a, lib and 12a and 12b in order to transmit the motion to the separation fingers 60 which are engaged to the same.

Advantageously, each displacement device 10a and 10b, at a respective first end portion 13a and 13b, in particular positioned along the first movement direction 101a, and 101b, and of a respective second end portion 14a, and 14b, positioned along the second displacement direction 102a, and 102b, is provided with a waiting zone 35a and 35b, at each of which a predetermined number of separation fingers 60 arranged in a row are collected. In particular, the first engagement member 25a, or 25b, and the second engagement member 125a, or 125b, if present, can be configured to engage the engagement portion 65 of a separation finger 60 at a time among the separation fingers 60 arranged in the respective waiting zone 35a, 35b, and in extraction zones 135a, and 135b positioned along the aforementioned second displacement directions 102a and 102b. At the zones 135a and 135b the separation fingers 60, one for each displacement device 10a, 10b, are extracted from stack 250 when a single stack of napkins is discharged towards the packaging zone.

Still with reference to the figures from 5A to 5F, in a possible embodiment of the invention, the additional first engagement member 26a, or 26b, and the second additional engagement member 126a, or 126b, if present, are arranged to engage the additional engagement portion 66 of the separation finger 60 from a first side, whilst the first engagement member 25a, or 25b, and the second engagement member 125a, or 125b, if present, are configured to engage the engagement portion 65 of the separation finger 60 from a second side opposite to the first side. In this way, the additional first engagement member 26a, or 26b, and the first engagement member 25a, or 25b, do not interfere one with the other during the respective actions for engaging, respectively, the additional engagement portion 66 and the engagement portion 65 of the separation finger 60. An analogous advantage is also obtained, when the second additional engagement member 126a, or 126b, and the second engagement member 125a, or 125b are provided.

In particular, each introduction device 20a and 20b, and each extraction device 120a, and 120b, if present, can comprise a respective first actuation device 80a, 80b,

180a and 180b, configured to operate a respective engagement member 25a, 25b, 125a, and 125b and to cause the same to move from the disengagement configuration to the engagement configuration and vice versa. More in particular, each first actuation device 80a, 80b, 180a, and 180b can be, furthermore, configured to cause the respective engagement member 25a, 25b, 125a, and 125b, to slide and, therefore, the separation finger 60 engaged to it, from/towards the respective introduction member 21a, 21b, 121a, 121b. In this way, the engaged separation finger 60, or a determined separation finger 60' positioned downstream of the same along the same row is caused to move from the waiting zone 35a, 35b, or the extraction zone 135a, and 135b, to the respective introduction member 21a, 21b, and 121a, 121b, of (figures 6, 7A and 7B).

According to an embodiment of the invention, the engagement members 25a and 25b, as well as the engagement devices 125a and 125b, if present, are rotatably connected to respective first actuation devices 80a, 80b, 180a, 180b and are configured to rotate, opposed by respective return elements 88a, 88b, 188a, 188b, for example a torsional spring, in a first direction of rotation 151 when, operated by the first actuation devices 80a, 80b, 180a, 180b to slide along a first direction 51, enters into contact with an edge 61 of a separation finger 60 defined by the engagement portion 65, for example a recessed portion. More precisely, once that the edge 61 of the separation finger 60 has been overcome by the aforementioned rotation in the first direction of rotation 151, the return element 88 causes the engagement members 25a, 25b, 125a, and 125b to rotate in a second direction of rotation 152 opposite to the first to bring the same in an engagement position of the second portion 65 of the separation finger 60 (figure 5B and 5C), or at a disengagement position of the same (figures 5E and 5F).

As diagrammatically shown in the figures from 5A to 5F, each actuation device 80a, or 80b, this latter not shown in the figure for reasons of simplicity, but identical for function and structure to the actuation device 80a, can comprise a fixed portion 81a, or 81b and a movable portion 85a, or 85b, arranged to move with respect to the fixed portion 81a, or 81b. In particular, the movable portion 85a, or 85b, is operatively connected to the aforementioned engagement member 25a, or 25b, and is configured to move the same in a first direction 51, or in a second direction 52, opposite to the first one. More in detail, when the movable portion 85a, or 85b, is operated to slide with respect to the fixed portion 81a, or 81b, it causes the engagement member 25a, or 25b, connected to it, to move in the same direction. Therefore, when during the aforementioned sliding in direction 51, the engagement member 25a, or 25b hits the edge 61 the aforementioned rotation in the first direction of rotation 151 occurs and once that the edge 61 of the same has been overcome, in the second direction of rotation 152. In case that also the aforementioned engagement members 125a and 125b are provided, respective actuation devices 180a and 180b can be provided which are analogous to the actuation devices 80a and 80b described above with reference to the figures from 5A to 5F.

According to an embodiment of the invention, the engagement seat 26a, and 26b, of each introduction member 21a, and 21b, and the engagement seat 126a, and 126b, of each extraction member 120a, and 120b, if present, has an inlet/outlet mouth 36a, 36b, 136a, and 136b which extends up to an edge 27a, 27b, 127a, and 127b of the introduction member 21a, 21b, 121a, 121b. Advantageously, the aforementioned inlet/outlet mouth 36a, 36b, 136a, and 136b is arranged to be positioned, alternatively, aligned with the third engagement member 11a, lib, or with the fourth engagement member 12a, 12b depending on the different phases of the introduction operations of the separation fingers 60 into the stack 250 of zigzag folded panels, and of extraction of the same.

In addition, or alternatively, each extraction device 120a, and 120b, can advantageously provide a second push member 122a, and 122b, configured to exert, in particular at a push surface 123a, or 123b, a push on the separation finger 60 positioned on the extraction member 120a, or 120b, such to cause the additional engagement portion 66 to be disengaged from the second additional engagement member 126a, or 126b, and to engage the third engagement member 11a, or lib.

In particular, the aforementioned push exerted by the push member, or by the second push member, is such to cause, respectively, the additional engagement portion 66 of the separation finger 60 to exit the aforementioned engagement seat 26a, or 26b and 126a, or 126b, through the inlet/outlet mouth 36a, 36b, 136a, 136b and, therefore, to cause the additional engagement portion 66 to engage into the groove 11a, or lib, 12a, 12b, of the displacement device 10a,o 10b.

According to an embodiment of the invention, each introduction device 20a and 20b, and each extraction device 120a, and 120b can comprise, furthermore, a respective second actuation device 90a, 90b, 190a and

190b, configured to move a respective introduction member, or a respective extraction member, respectively along the aforementioned introduction direction 103a, and 103b, and the aforementioned extraction direction 104a, and 104b. In particular, analogously to what described above in connection with the first actuation devices, also the aforementioned second actuation devices can comprise a fixed portion 91a, 91b, 191a, 191b and a movable portion

95a, 95b, 195a, 195b arranged to move with respect to the fixed portion 91a, 91b, 191a, 191b. In particular, the movable portion 95a, 95b, 195a, 195b is operatively connected by connection members 96a to the aforementioned introduction member 21a, or 21b, or to the aforementioned extraction member 121a, or 121b, and is configured to move the same in the introduction direction, or in the extraction direction. More in detail, when the movable portion 95a, 95b, 195a, 195b is actuated to slide with respect to the fixed portion 91a, 91b, 191a, 191b, it causes the extraction member connected to it to move in the same direction.

In particular, at each waiting zone an abutment surface is provided arranged to stop the first separation finger 60 of a respective row of separation fingers, when the introduction member 21a, or 21b, is arranged to translate along the aforementioned introduction direction 103a, or 103b the separation finger 60 positioned on the same to be moved from the first displacement direction 101a, or 101b, to the second displacement direction 102a, or 102b, or when the extraction member 120a, or 120b, is arranged to translate along the aforementioned extraction direction 104a, or 104b, to bring the separation finger 60 positioned on the same from the second displacement direction 102a, or 102b, to the first displacement direction 101a, or 101b. In a possible embodiment, the aforementioned abutment surface can be constituted by the face of the introduction member 21a, or 21b, or the extraction member 120a, or 120b, facing towards the displacement device 10a, or 10b. Alternatively, the abutment surface can be a surface of a stop element arranged to act to stop the first separation finger 60 of the row when the introduction member, or the extraction member, is moved along the aforementioned introduction direction 103a, or 103b, and the introduction direction 104a, or 104b.

In a particular embodiment of the invention, the push member and the engagement member positioned at the same end portion of the first displacement device 10a, or of the second displacement device 10b, are operatively connected to the same actuation device, advantageously the same movable portion of this. Therefore, in this case, the engagement member and the second push member are simultaneously operated for carrying out the respective operations. More precisely, the first actuation device 80a, or 80b, can be arranged to operate, at the same time, the first engagement member 25a, or 25b, and the push member

22a, or 22b, in a first actuation direction in order to cause the first engagement member 25a, or 25b, to move from the disengagement configuration to the engagement configuration and, at the same time, the push member 22a, or 22b, to move from the push configuration to the rest configuration. Analogously, the first actuation device 80a, or 80b, can be arranged to operate at the same time the first engagement member 25a, or 25b, and the push member

22a, or 22b, in a second actuation direction in order to cause the first engagement member 25a, 25b to move from the engagement configuration to the disengagement configuration and the push member 22a, or 22b, to move from the rest configuration to the push configuration.

According to an alternative embodiment, the linear electric motors 80a, 80b, and 90a, 90b, and the additional electric motors 180a, 180b, and 190a, 190b, if present, impart to the respective components connected to the same, the translation movements necessary to introduce, and in case, to extract, the separation fingers 60 i.e. along the first displacement direction 101a, or 101b, and along the second displacement direction 102a, or 102b, and the movements necessary to translate along the introduction direction 103a, 103b, and, in case, along the extraction direction 104a, and 104b. The actuation device 80a, or 80b, is connected both to the push member 22a, or 80b, and to the engagement member 25a, or 25b. Therefore, by operating the electric motor of the actuation device 80a, or 80b, in direction 51 of figure 5A the engagement member 25a, or

25b, is introduced into the engagement portion 65 of a separation finger 60 and, at the same time, a separation finger is introduced into the longitudinal groove 12a, or 12b, in such a way to free the introduction member 21a, or 21b, which can be loaded with a new separation finger. The separation finger 60 as it is introduced into the groove 12a, or 12b, entering into contact with the motion transmission device 16a, or 16b, begins to advance with a speed about equal to that of the plurality of zigzag folded panels 250. The introduction of the separation finger 60 into the groove 12a, or 12b, coincide also with the introduction of the same into the plurality of folded panels 250. The introduction is carried out in phases with the separation fingers 205a and 205b in such a way to insert a separation finger exactly between a panel and the other defining the separation between the group of the previous and the group of the following panels being formed. In practice, the separation finger 60 before being inserted into the groove 12a, or 12b, is caused to wait close and, preferably, internally to the folding rollers

201a and 201b in a zone of no interference with the panels in order to reduce as much as possible the introduction stroke.

By actuating the motor 90A along the direction 103a the introduction member 21a, or 21b, is taken back in such a way to align the additional engagement member 26a, or 26b, with the displacement direction 101a, or 101b, in order to load a new separation finger 60 waiting in the waiting zone 35a, or 35b, and already engaged with the engagement member 25a, or 25b.

By actuating again the electric motor of the actuation device 80a, or 80b, along the direction 52 of figure 5c, the separation finger 60 is introduced into the introduction member 21a, or 21b, through the inlet/outlet mouth 36a, or 36b. At the same time the push member 22a, or 22b, to withdraw in a direction of approaching towards the folding roller 201a, or 201b, in such a way to leave the space to a new separation finger 60 as the introduction member 21a, or 21b is inserted.

At last, by actuating the motor of the actuation device 90a, or 90b, the introduction member 21a, or 21b, is translated along the direction 103a, or 103b, aligning the inlet/outlet mouth 36a, or 36b, with the displacement direction 102a, or 102b, moving the new separation finger 60 at the first end portion 13a, or 13b, ready to be introduced into the plurality of folded panels 250 at the following operation of the push member 22a, or 22b, operated by the actuation device 80a as previously described finishing a whole introduction cycle.

The extraction cycle in the case of the alternative embodiment described above with reference to the figures IB and 2, is carried out by a sequence of analogous operations. More precisely, a separation finger 60, introduced into the plurality of zigzag folded panels 250, moving along the displacement direction 102a, or 102b, is engaged by the second engagement member 125a, or 125b, operated by the actuation device 180a, or 180b, by a linear electric motor. In this step the separation finger 60 is disengaged by the motion transmission device 16a, or 16b. By actuation device 180a, or 180b, the advancement of separation finger 60 can be temporarily stopped, in such a way to create a gap between a stack of folded panels 250 and the following one. The creation of a gap together with a system of discharge of the napkins as described in EP2396250 allows to improve and to increase the productivity and reliability of the folding machine. The separation finger 60 maintain the stack compacted as a blade not shown enters into contact with the front surface of the first panel allowing the previous stack of panels to be discharged. Once that the blade for holding the front part of the stack of panels 250 has been introduced, it is possible to extract the separation finger 60. The extraction is carried out by causing the separation finger 60 to advance along the direction 102a, or 102b, by the actuation device 180a, or 180b, introducing into the introduction member 121a, or 121b. Then, the introduction member 121a, or 121b, is caused to translate along the direction 104a, or 104b, aligning the inlet/outlet mouth 136a, or 136b, with the displacement direction 101a, or 101b. By translating the push member 122a, or 122b, along direction 52 of fig. 5c, the separation finger 60 is removed from the introduction member 121a, or 121b, introducing the same into the groove 11a, or lib. In this way the separation finger 60 is moved by the motion transmission device 16a, or 16b, towards the waiting zone 35a, or 35b. The actuation device 180a, or 180b, is connected both to the push member 122a, or 122b, and to the second engagement member 125a, or 125b, if present. Therefore, by actuating the electric motor of the actuation device 180a, or 180b, in direction 52 of figure 5C the engagement member 25a, or 25b, is introduced into the engagement portion 65 of a separation finger 60 introduced into the plurality of folded panels 250 and, at the same time, a separation finger 60 is positioned into the longitudinal groove 11a, or lib, in such a way to free the introduction member 121a, or 121b, which can be loaded with a new separation finger when it will be removed from the plurality of folded panels 250.

In the embodiment of the invention diagrammatically shown in figure 11, the first actuation device 80a, or 80b and the second actuation device 90a, or 90b comprise, respectively, a first and a second electric motor 82a, or 82b and 92a, or 92b respectively provided with a first and a second motor shaft 83a, or 83b and 93a, or 93b arranged to rotate about a respective rotation axis 183a, or 183b and 193a, or 193b. In particular, a first and a second device for converting the motion 84a, or 84b and 94a, or 94b can be provided that are operatively connected, respectively, to said first and second motor shafts 83a, or 83b and 93a, or 93b and configured to convert the rotational motion of the respective motor shaft 83a, or 83b and 93a, or 93b into a rectilinear motion. For example, the device for converting the motion 84a, or 84b and 94a, or 94b can provide a pinion member, not shown in the figure, that is mounted on a respective rotation shaft 83a, or 83b and 93a, or 93b and a rack member 86a, or 86b, and 96a, or 96b that is partially visible in figure 11, configured to engage one with the other, in such a way to convert the rotational motion of the rotation shafts 83a, or 83b and 93a, or 93b into a rectilinear motion.

The foregoing description of a specific embodiment will so fully reveal the invention according to the conceptual point of view, so that others, by applying current knowledge, will be able to modify and/or adapt for various applications such an embodiment without further research and without parting from the invention, and it is therefore to be understood that such adaptations and modifications will have to be considered as equivalent to the specific embodiment. The means and the materials to realise the different functions described herein could have a different nature without, for this reason, departing from the field of the invention. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.