A multi-format interfolding machine and a corresponding method for format change

Abstract

A multi-format interfolding machine (100) comprising a frame with a plurality of parts (10, 11, 12, 13, 14), at least a connection (71, 72, 73, 74) which makes the parts movable with respect to one another, and an interfolding unit comprising overlapping means with a first roller (2) comprising first retaining means (22) sheets (A) for a first format (s1) and rotatable with respect to a first part (11), a second roller (2') comprising second retaining means (22) sheets (A) for a second format (s2) and rotatable with respect to a second part (12) and an overlapping roller (4) which is rotatable with respect to a part (10). - the at least a connection (71, 72, 73, 74) is configured in such a way that the first part (11) and the second part (12) are movable with respect to the part (10) and in such a way as to guide the plurality of parts (10, 11, 12, 13, 14) from a first to a second arrangement (A1, A2) for realising a first and a second format (s1, s2).

Description

[0001] A MULTI-FORMAT INTERFOLDING MACHINE

[0002] AND A CORRESPONDING METHOD FOR FORMAT CHANGE

[0003] DESCRIPTION OF THE INVENTION

[0004] FIELD OF THE INVENTION

[0005] The present invention concerns the technical sector relating to the production of packs of interfolded sheets, i.e. with the sheets, or articles in sheet form, folded in a zig-zag with respect to one another; typically the sheets are made of paper material, having one or more ply, and the packs can, for example, be packs of paper handkerchieves, paper napkins or paper hand towels. In greater detail, the present invention relates to a multi-format interfolding machine, i.e. which can realise different interfolded packs without the extraction of rollers from the machine and the introduction of other rollers into the machine, and a method for varying a format in a multi-format interfolding machine. As more fully described in the following, a multi-format interfolding machine enables production of formats which are differentiated by the length of the sheets, a commonly indicated characteristic indicated by the term “cut-off”, and / or a number of panels and / or position of the overlapped portions of the sheets.

[0006] DESCRIPTION OF THE PRIOR ART

[0007] In this technical sector, the sheets that are to be folded in an interfolded way for the formation of a stack of sheets (pack) are usually infed in the form of continuous reels, or strips, typically obtained from unwinding means starting from reels of paper, cross cutting means which define the articles in sheet form and reach folding means which carry out one or more folds on each sheet. Usually the stack of sheets under formation is supported by support means and the separation between packs of sheets, once a desired number of interfolded sheets has been reached, is carried out by separation means.

[0008] The cutting means can define the articles in sheet form by separating the sheets from one another, by straight cuts, also known by the term “Clean-cuts", or by making lines, or points, of pre-cuts, also known by the term “Tab-bonds", between the articles in sheet form.

[0009] When the sheets are folded in a zig-zag fashion with one another by the folding means, portions are determined in each sheet that are separated from one another by a respective fold: each of these portions is usually termed a panel. The sheets with a plurality of folds are also known by the term “multi-fold” while those with only one fold are known as “single-fold’. It is therefore possible to realise packs of interfolded sheets with folds having 2 panels, 3 panels, 4 panels and so on. The sheets with 4 panels with the panels having, or having approximately, the same length are also known as W folded sheets while those with 3 panels having the same length are also known as Z folded sheets. The expert in the sector will understand how the length of the panels might not correspond exactly as minimal variations in the positioning of the components of the interfolding machines can lead to dimensional variations. To this can be added that these machines operate typically at high velocities and that typically the sheets are made of paper material, or in any case of a material with like characteristics; the paper material can be subjected to different levels of tension which can in turn lead to dimensional variations.

[0010] Typically the folding of the sheets takes place with the use of two folding rollers beneath which the support means support the stack of interfolded sheets under formation.

[0011] The extension and the reciprocal position of the portions of overlapped sheet vary according to the specific product or format, for example in the case of three panels, or Z panels, a panel overlapped with the successive sheet can be obtained while in the case of four panels, or W panels two overlapped panels can be obtained with the successive sheet, as can be observed by way of example in figures from 3 to 6. Figure 3 is a schematic representation of a pack of interfolded sheets in Z panels, figure 4 is a schematic representation of a sequence of overlapped interfolded sheets for realising the pack of figure 3, figure 5 is a schematic representation of a pack of interfolded sheets in Z panels and figure 6 is a schematic representation of a sequence of overlapped interfolded sheets for realising the pack of figure 5.

[0012] The overlapping of the sheets can take place by overlapping two sequences of sheets in such a way that the sheets of one sequence are staggered with respect to the sheets of the other, or by difference of velocity starting from a sequence. In the case of overlapping due to difference of velocity, prior to reaching the folding means the velocity of the sheets is reduced so that successive sheets of the sequence partially overlap with respect to one another. In other words, the sheets of the sequence will be moved at a first velocity in a first portion and at a second velocity, lower than the first velocity, in a second portion, successive to the first portion, so as to obtain the desired overlapping.

[0013] In a very widely used approach, the interfolding machines utilise rollers comprising gripping means for retaining the sheets or the articles in sheet form; notwithstanding this, the expert in the sector is aware of alternative solutions for transport of the sheets, such as for example a plate or belt conveyor, which can be integrated or which can substitute the use of some rollers. The gripping means typically used are holes or suction openings, connected to a suction system, and / or mechanical gripping pliers.

[0014] A prior art interfolding machine which overlaps the sheets by difference in velocity can also comprise cutting means for cutting continuous strips comprising a cutting roller and at least a counter-blade which cooperates with the cutting roller, a transfer roller, which receives the sheets cut from the cutting roller, an overlapping roller which receives the sheets from the transfer roller, and folding rollers for folding the articles in sheet form which receives the articles from the overlapping roller.

[0015] For the above-illustrated reasons, the overlapping takes place due to the different tangential velocity between the transfer roller and the overlapping roller, to the arrangement of the suction openings and, in general, to the presence of special recesses in the transfer roller for housing a portion of sheet, as can be observed by way of example in figures 1 and 2. In figures 1 and 2 the transfer rollers of the two interfolding units have the same diameter but are configured for formats of packs of interfolded sheets that are different, i.e. the surface thereof has the same length but the sheets are sub-divided into a number of portions, which define angles of circumference that are identical, that are different.

[0016] In a like embodiment, the length of the sheets is determined by the cutting roller, in particular by the circumference thereof and by the position of the cutting blade or blades, the entity of the overlapping is determined by the difference of velocity between the transfer roller and the overlapping roller while the folding rollers determine the number of panels.

[0017] Each type of pack of interfolded sheets requires specific parameters of the various components: traditionally interfolding machines were manufactured for a specific production. This is also in the light of a high velocity of material, typically paper, which often requires an important preliminary step of testing, i.e. identification of the correct working parameters before start of production and, often, following the replacement of components.

[0018] In order to obviate these traditional issues regarding single-format interfolding machines two different approaches have been proposed.

[0019] A first approach relates to simplifying the replacement of the rollers for a format change, such as for example described in European patent application EP 1630118 A1 , so as to reduce times and the technical drawbacks linked to this operation. Other examples are described in US 2007203007 A1 , in WO 2023156926 A1 and in WO 2023021386 A1 .

[0020] A second approach proposes multi-format interfolding machines which can realise, for example, interfolded packs of articles in sheet form in Z and W configurations without replacement of the rollers.

[0021] A further example of a multi-format interfolding machine is disclosed in international patent application published with number WO 2018 / 005099 A1 , which discloses an interfolding machine that divides a single paper infeed line into two production lines so as to improve productivity, given a same production volume, but also, possibly, so as to produce different formats.

[0022] A further example of a multi-format interfolding machine is disclosed in European patent application published with number EP 2308786 A1 , which, for example, with reference to respective figures 2A and 2B, describes a transfer roller which adapts to a plurality of formats in an interfolding machine which comprises a transfer roller that cooperates with an overlapping roller and which has a tangential velocity that is greater than that of the overlapping roller so as to enable the overlapping of the sheets on the overlapping roller. The same application EP 2308786 A1 illustrates, for example, with reference to figures 4A, 4B, and 4C, a cutting roller that can pass from a first length of the articles in sheet form to a second length due to the fact that the transfer roller can operate both with the first length and with the second length owing to the possibility of exploiting a plurality of suction openings and a plurality of recesses of the surface of the transfer roller.

[0023] Other examples are described in in US 2012202670 A1 and in US 2010075820 A1.

[0024] Among other things, reference is made to the documents mentioned in the foregoing regarding the typical solutions used in the sector known to the expert and described by way of summary in the prior art.

[0025] Still today, an interfolding machine is needed that enables realising packs of sheets, with a plurality of folds, i.e. interfolded sheets of different formats with no need to replace the rollers, with no need to have many non-operating elements, or elements operating with lower productivity, having smaller dimensions, which does not require designs of components that are particularly complex and / or which is easy to realise and / or maintain with respect to the performances achieved therewith. Though the abovementioned solutions can respond positively to some needs, they however have limits with regard to other applications. For example: the solution of EP 1630118 A1 doubles some components and requires storage spaces for the non-operating rollers, the solution of WO 2018 / 005099 A1 doubles some components and risks increasing volumes given a same productivity in a case of production requirements for one type of format alone and the solution of EP 2308786 A1 complicates the realisation of the transfer roller and might not allow some format combinations owing to the space occupied by various elements internally of the roller, for appropriately retaining the sheets.

[0026] SUMMARY OF THE INVENTION

[0027] The present invention intends to obviate one or more drawbacks of the solutions of the prior art.

[0028] A first aim of the present invention is to provide an interfolding machine of a multiformat type, i.e. which can produce interfolded packs of articles in sheet form that differ from one another without replacement of the rollers installed on the machine. A further aim of the present invention is to simplify the realising of a multi-format interfolding machine.

[0029] A further aim of some embodiments is to enable a format change that is simple, rapid and / or repeatable, i.e. one that limits the demand for or does not requires priorly identifying the correct working parameters at each format change.

[0030] A further aim of some embodiments is to reduce energy consumption and / or wear on components.

[0031] These and other aims, which will be obvious to the expert in the sector from a reading of the following text, are attained by means of an multi-format interfolding machine for realising, from a strip, packs of interfolded sheets of different formats or a method for varying a format in a multi-format interfolding machine according to the contents of the claims.

[0032] According to the teachings of the present description, the multi-format interfolding machine comprises a frame comprising a plurality of parts, cutting means for cutting strip so as to realise a sequence of sheets with each sheet having a front part and a rear part, an interfolding unit for interfolding the sequence of sheets, movement means and at least a connection, each connection making parts of the plurality of parts movable with respect to one another. The interfolding unit comprises overlapping means for superposing the sheets on one another, which comprise a first roller and an overlapping roller and folding means for folding overlapped sheets so as to interfold the sheets.

[0033] The first roller comprises a first surface for accommodating sheets and first retaining means of sheets on the first surface and the overlapping roller comprises a surface for accommodating sheets and retaining means of sheets on the surface.

[0034] A first part of the plurality of parts comprises a first seat which houses the first roller, which is rotatable with respect to the first part about a first rotation axis and a part of the plurality of parts comprises a seat which houses the overlapping roller, which is rotatable with respect to the part about a rotation axis.

[0035] The movement means are configured to set the first roller in rotation with respect to the first part and the overlapping roller with respect to the part so that the tangential velocity of the first roller is greater than the tangential velocity of the overlapping roller.

[0036] In a relative first position between the first roller and the overlapping roller, the first surface and the surface are at a distance which enables the retaining means to attract the sheets onto the surface from the first surface.

[0037] The first retaining means and the retaining means are configured in such a way that the surface receives the front part of a sheet before the rear part of the preceding sheet, thus superposing successive sheets on the surface, in the relative first position.

[0038] The overlapping means advantageously comprise a second roller which comprises a second surface for accommodating sheets and second retaining means of sheets on the second surface. A second part of the plurality of parts comprises a second seat which houses the second roller which is rotatable with respect to the second part about a second rotation axis.

[0039] The movement means are configured to set the second roller in rotation with respect to the second part and the overlapping roller with respect to the part so that the tangential velocity of the second roller is greater than the tangential velocity of the overlapping roller.

[0040] In a first reciprocal position between the second roller and the overlapping roller, the second surface and the surface are at a distance which enables the retaining means to attract the sheets onto the surface from the second surface.

[0041] The second retaining means and the retaining means are configured in such a way that the surface receives the front part of a sheet before the rear part of the preceding sheet, thus superposing successive sheets on the surface, in the first reciprocal position.

[0042] The first retaining means are configured for a first format and the second retaining means are configured for a second format different to the first format.

[0043] The at least a connection is configured in such a way that the first part and the second part are movable with respect to the part and in such a way as to guide the plurality of parts from a first arrangement of the plurality of parts, in which the first roller occupies a volume and is in the relative first position and the second roller frees the volume, to a second arrangement of the plurality of parts, in which the first roller frees the volume and the second roller occupies the volume and is in the first reciprocal position, so as to realise a first format in the first arrangement and a second format, different to the first format, in the second arrangement.

[0044] According to the teachings of the present description, the method comprises steps of:

[0045] - providing a multi-format interfolding machine according to the present description;

[0046] - moving parts of the plurality of parts, so that the plurality of parts pass from the first arrangement to the second arrangement, realising at least a displacement of the first part and of the second part with respect to the part, the at least a displacement being guided by the at least a connection.

[0047] BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Specific embodiments of the invention will be described in the following part of the present description, according to what is set down in the claims and with the aid of the accompanying figures, in which: figure 1 and figure 2 are schematic views in section of a respective singleformat interfolding machine of the prior art which realises packs of interfolded sheets of different formats; figures from 3 to 6 are schematic illustrations of packs of interfolded sheets in a W and Z configuration and relative sequences of sheets to realise them; figure 7 is a schematic view in section of an embodiment of a multi-format interfolding machine according to the invention with the rollers arranged so as to realise a second format of packs of interfolded sheets; figure 8 is a schematic view in section of the embodiment of figure 7 with the rollers arranged so as to realise a first format of packs of interfolded sheets that is different to the second format; figure 9 is a rear axonometric view of an embodiment of a multi-format interfolding machine according to the invention; figure 10 is a section view of the embodiment of figure 9 with the cutting plane vertical and passing at halfway beween a front portion and a rear portion of frame; figure 11 is a frontal view of the embodiment of figure 9 with some components not illustrated, in order to observe the front frame in a second arrangement; figure 12 is a frontal view of the embodiment of figure 9 with some components not illustrated, in order to observe the front frame in a first arrangement; figure 13 is a view of a transfer roller of the embodiment of figure 9 with a trace line of the cutting plane of the following figure; figure 14 is a partial axonometric section view of figure 13; figure 15 is a frontal axonometric view of a further embodiment of the invention, alike to the embodiment of figure 9, with some components not illustrated; figure 16 is a schematic section view of the embodiments of figures 9 and 15 with the parts of the front frame in a first arrangement; figures 17 and 18 illustrate, with schematic section views, a sequence of displacements among the parts of the frame for passing from the first arrangement of figure 16 to a second arrangement of figure 19; figure 19 is a schematic section view with the parts of the front frame in a second arrangement; figures 20 and 21 are views, complete with larger-scale views, of some components of the embodiment of figure 15 with the rollers and relative cogwheels respectively in a proximal position and in a moved-away position; figures 22 and 23 respectively show figures 20 and 22 without a cogwheel; figure 24 is an axonometric view of a further embodiment of a multi-format interfolding machine according to the invention; figure 25 is an axonometric view of a still further embodiment of the multiformat interfolding machine according to the invention alike to the one in figure 24 in a different arrangement; figures 26 and 27 schematically illustrate a first and a second arrangement which enable realising different formats with the embodiments of figures 24 and 25; figure 28 is a schematic view in section, alike to the one in figure 19, but with the rollers removed in order to illustrate the seats and parts of the front frame. With reference to the appended figures, reference numeral 100 denotes a multiformat interfolding machine.

[0049] The references are included to facilitate comprehension of the invention, but do not limit the scope of protection.

[0050] DESCRIPTION OF PREFERRED EMBODIMENTS

[0051] An embodiment of the multi-format interfolding machine (100) comprises:

[0052] - a frame which comprises a plurality of parts (10, 11 , 12, 13, 14);

[0053] - cutting means for cutting strip (N), with a clean cut, so as to realise a sequence of sheets (A) with each sheet (A) having a front part (Pf) and a rear part (Pr);

[0054] - an interfolding unit for interfolding the sequence of sheets (A) comprising o overlapping means for superposing the sheets (A) on one another which overlapping means comprise a first roller (2) and an overlapping roller (4) and o folding means for folding overlapped sheets (A) so as to interfold the sheets (A);

[0055] - movement means; and

[0056] - at least a connection (71 , 72, 73, 74), each connection making parts of the plurality of parts (10, 11 , 12, 13, 14) movable with respect to one another.

[0057] The first roller (2) comprises a first surface (21 ) for accommodating sheets (A) and first retaining means (22) of sheets (A) on the first surface (21 ).

[0058] The overlapping roller (4) comprises a surface (41 ) for accommodating sheets (A) and retaining means (42) of sheets (A) on the surface (41 ).

[0059] A first part (11 ) of the plurality of parts (10, 11 , 12, 13, 14) comprises a first seat (11a) which houses the first roller (2); the first roller (2) is rotatable with respect to the first part (11 ) about a first rotation axis (X1 ).

[0060] A part (10) of the plurality of parts (10, 11 , 12, 13, 14) comprises a seat (10a) which houses the overlapping roller (4); the overlapping roller (4) is rotatable with respect to the part (10) about a rotation axis (X).

[0061] The movement means are configured to set the first roller (2) in rotation with respect to the first part (11 ) and the overlapping roller (4) with respect to the part (10) so that the tangential velocity of the first roller (2) is greater than the tangential velocity of the overlapping roller (4).

[0062] In a relative first position (RP) between the first roller (2) and the overlapping roller (4), the first surface (21 ) and the surface (41) are at a distance which enables the retaining means (42) to attract the sheets (A) onto the surface (41 ) from the first surface (21 ).

[0063] The first retaining means (22) and the retaining means (42) are configured in such a way that the surface (41 ) receives the front part (Pf) of a sheet (A) before the rear part (Pr) of the preceding sheet (A), thus superposing successive sheets (A) on the surface (41 ), in the relative first position (RP).

[0064] Advantageously:

[0065] - the overlapping means comprise a second roller (2’) which comprises a second surface (21’) for accommodating sheets (A) and second retaining means (22’) of sheets (A) on the second surface (21’);

[0066] - a second part (12) of the plurality of parts (10, 11 , 12, 13, 14) comprises a second seat (12a) which houses the second roller (2’); the second roller (2’) being rotatable with respect to the second part (12) about a second rotation axis (X2);

[0067] - the movement means are configured to set the second roller (2’) in rotation with respect to the second part (12) and the overlapping roller (4) with respect to the part (10) so that the tangential velocity of the second roller (2’) is greater than the tangential velocity of the overlapping roller (4);

[0068] - in a first reciprocal position (MP) between the second roller (2’) and the overlapping roller (4), the second surface (21’) and the surface (41 ) are at a distance which enables the retaining means (42) to attract the sheets (A) onto the surface (41 ) from the second surface (21’);

[0069] - the second retaining means (22’) and the retaining means (42) are configured in such a way that the surface (41 ) receives the front part (Pf) of a sheet (A) before the rear part (Pr) of the preceding sheet (A), thus superposing successive sheets (A) on the surface (41 ), in the first reciprocal position (MP); and

[0070] - the first retaining means (22) are configured for a first format (s1 ) i.e. are configured to retain a type of sheets (A) which enables obtaining a first format (s1 ), and the second retaining means (22’) are configured for a second format (s2) i.e. are configured to retain a type of sheets (A) which enable obtaining a second format (s2), different to the first format (s1 ). Further, the at least a connection (71 , 72, 73, 74) is configured:

[0071] - in such a way that the first part (11 ) and the second part (12) are movable with respect to the part (10);

[0072] - in such a way as to guide the plurality of parts (10, 11 , 12, 13, 14) from a first arrangement (A1 ) of the plurality of parts (10, 11 , 12, 13, 14), in which the first roller (2) occupies a volume (V) and is in the relative first position (RP) and the second roller (2’) frees the volume (V), to a second arrangement (A2) of the plurality of parts (10, 11 , 12, 13, 14), in which the first roller (2) frees the volume (V) and the second roller (2’) occupies the volume (V) and is in the first reciprocal position (MP), so as to realise a first format (s1 ) in the first arrangement (A1 ) and a second format (s2), different to the first format (s1 ), in the second arrangement (A2).

[0073] The above-described multi-format interfolding machine (100) enables realising a first format (s1 ) of packs of interfolded sheets (I) and a second format (s2) of packs of interfolded sheets (I) without replacing any roller on the machine, i.e. without extracting the first roller (2) and introducing the second roller (2’). This is possible owing to the presence of a second roller (2’) and at least a connection (71 , 72, 73, 74) that guides the plurality of parts (10, 11 , 12, 13, 14) from a first arrangement (A1 ) and a second arrangement (A2).

[0074] Without the replacement of the first roller (2) it is possible to change format (s1 , s2) more rapidly and it is possible to simplify or eliminate the preliminary operations, for example of adjustment of the phase or distance between the rollers.

[0075] The first roller (2) and the second roller (2’) can be of traditional type, i.e. a particularly complex design is not necessary to enable a plurality of configurations of the first roller (2), and facilitate combinations of formats (s1 , s2) that are hard to obtain by working on a single roller with several operating configurations.

[0076] In general the rollers of the interfolding machines are not mounted in a cantilever fashion but are interposed between a front frame and a rear frame. In order not to overload the present description, as well as to comprise the case of mounting the rollers in a cantilever fashion, the present text describes the invention with respect to a plurality of parts (10, 11 , 12, 13, 14) on a same side, which is the front side in the appended example figures. With the aim of clarifying the specular behaviour of the parts of the rear frame, some references have been added which terminate with the letter “r” attached to the plurality of parts (10r, 11 r, 12r, 13r). The same operation might clearly be carried out for the other components, for example the at least a connection (71 , 72, 73, 74), passing from the first arrangement (A1 ) to the second arrangement (A2). The expert in the sector will understand how some components, for example the at least an actuator (81 , 82, 83), might not be replicated on both sides, though it is preferable to ensure precise displacements to avoid tensions on the components which would transmit the movement from one side to the other.

[0077] In an embodiment of known type, the retaining means in general, i.e. the first retaining means (22), the second retaining means (22), the retaining means (42) and the third retaining means (32) described in the following typically comprise suction holes or openings (24), connected by means of an aspirating conduit (23) and a suction system, and / or mechanical gripping pliers.

[0078] The multi-format interfolding machine (100) preferably comprises at least an actuator (81 , 82, 83). Each actuator displaces, among themselves, parts of the plurality of parts (10, 11 , 12, 13, 14) and the at least an actuator (81 , 82, 83) is configured to bring the plurality of parts (10, 11 , 12, 13, 14) from the first arrangement (A1 ) to the second arrangement (A2) and / or, preferably and, from the second arrangement (A2) to the first arrangement (A1 ).

[0079] The use of at least an actuator (81 , 82, 83) further simplifies the format change (s1 , s2) which can then be managed by a control unit of the at least an actuator (81 , 82, 83), including remotely.

[0080] The first roller (2), in the first arrangement (A1 ), and the second roller (2’), in the second arrangement (A2), are preferably arranged with respect to the part (10) in such a way as to transfer the front part (Pf) of the sheets (A) to a same inlet area (In). More preferably the inlet area (In) is at the upper end of the overlapping roller (4).

[0081] The step of overlapping the sheets (A) by difference of velocity is a critical step and an as similar as possible behaviour between the first roller (2) and the second roller (2’) simplifies the design and / or the manufacture. For example, in the case of the involvement of other components, the components must not be repositioned or uncoupled. It is further possible to position the inlet of the sheets (A) in the upper area of the overlapping roller (4) for both the first roller (2) and the second roller (2’) so that the overlapping on the surface (41 ) takes place in a portion that moves away from the first roller (2) and the second roller (2’), in the rotation direction of the overlapping roller (4).

[0082] In a preferred embodiment:

[0083] - the first rotation axis (X1 ) in the first arrangement (A1 ) and the second rotation axis (X2) in the second arrangement (A2) have the same position with respect to the part (10);

[0084] - the first roller (2) and the second roller (2’) have or substantially have the same outer diameter;

[0085] - the first retaining means (22) subdivide the first surface (21 ) in a first number of portions which define angles of circumference (alfa) that are equal to one another, or substantially equal to one another, with each portion retaining a sheet (A);

[0086] - the second retaining means (22’) subdivide the second surface (21’) in a second number of portions which define angles of circumference (alfa) that are equal to one another, or substantially equal, to one another, with each portion retaining a sheet (A); and

[0087] - the second number is different to the first number.

[0088] This realisation enables production of two formats (s1 , s2) by simply modifying the arrangement of the retaining means. The same outer diameter allows replication of the same transfer from a first point towards the overlapping roller (4); this is particularly convenient in a case where the first roller (2) and the second roller (2’) directly receive the sheets (A) from a cutting roller (3), illustrated herein below.

[0089] The same outer diameter is advantageously applied in the production of packs of interfolded sheets (I) in a W or Z configuration. The first surface (21 ) and the second surface (2T) have, or have substantially the same length when the first roller (2) and the second roller (2’) have or substantially have the same outer diameter. With a length that is a multiple of 3 and 4, it is possible to obtain packs of interfolded sheets (I) in both W and Z configuration. For example, with a circumference of 960 mm it is possible to define sheets (A) of a first length (L1 ) of 320 mm and sheets of a second length (L2) of 240 mm, thus being able to realise, respectively, packs of interfolded sheets (I) in a W andr Z configuration, i.e. a first format (s1 ) and a second format (s2) with the folds equally spaced from one another (80 mm). The sequence of sheets (A) might be obtained from the strip (N) using cutting means which comprise cutters interposed between a reel unwinder which usually supplies the strip (N) and sheet conveyors (A), for example a plate or aspirated belt conveyor, located upstream of the first roller (2) and the second roller (2’). Otherwise, first cutters of the cutting means might be borne by the first roller (2) and the second roller (2’) and cooperate with second cutters of the cutting means.

[0090] The multi-format interfolding machine (100) is particularly compact and / or has high productivity and / or guarantees excellent quality in the case of use of a cutting roller (3), especially when this directly transfers the sheets (A) onto the first roller (2) and second roller (2’). This option also avoids complications on these rollers due to the need to find space for the first cutters.

[0091] The cutting means preferably comprise a first counter-blade (30), or blade, and a cutting roller (3) which comprises a third surface (31 ) for accommodating sheets (A), third retaining means (32) of strip and / or sheets (A) on the first surface (31 ) and at least a blade (33), or counter-blade, which cooperates with the first counterblade (30), or blade, to cut the strip (N) so as to realise the sequence of sheets (A).

[0092] A third part (13) of the plurality of parts (10, 11 , 12, 13, 14) comprises a third seat (13a) which houses the cutting roller (3); the cutting roller (3) is rotatable with respect to the third part (13) about a third rotation axis (X3).

[0093] The movement means are configured to set the cutting roller (3) in rotation with respect to the third part (13) and the first roller (2) with respect to the first part (11 ) so that the tangential velocity of the cutting roller (3) is equal to the tangential velocity of the first roller (2).

[0094] The movement means are configured to set the cutting roller (3) in rotation with respect to the third part (13) and the second roller (2’) with respect to the second part (12) so that the tangential velocity of the cutting roller (3) is equal to the tangential velocity of the second roller (2’).

[0095] In the first arrangement (A1 ), the first surface (21 ) and the third surface (41 ) are at a distance which enables the first retaining means (22) to attract the sheets (A) onto the first surface (21 ) from the third surface (31 ).

[0096] In the second arrangement (A2), the second surface (21’) and the third surface (41 ) are at a distance which enables the second retaining means (22’) to attract the sheets (A) onto the second surface (21’) from the third surface (31 ).

[0097] Typically, as shown by way of example in figures 7, 8, 10 and 16, the cutting means are configured to cut sheets (A) of a first length (L1 ) or, alternatively, of a second length (L2). Consequently the first retaining means (22) are configured for sheets (A) of the first length (L1 ), so as to obtain the first format (s1 ), and the second retaining means (22’) are configured for sheets (A) of the second length (L2), so as to obtain the second format (s2).

[0098] As already discussed in terms of the first roller (2) and the second roller (2’), a same cutting roller (3) can generate sheets (A) having a different length by varying the positions of the at least a blade (33). Figures 7, 8, 10 and 16 show how the cutting roller (3) can operate both with four blades (33) which form right angle among them and with three blades (33) which form angles of 120° (sexagesimal) among them. With reference to the above example, i.e. of a circumference of 960 mm, in the first case sheets (A) of 240 mm, and in the second case of 320 mm will be obtained.

[0099] In general, the multi-format interfolding machine (100) comprises a fixed cutting beam, i.e. not rotatable with respect to the frame, comprising the first counter- blade (30) or, possibly, a first blade. More preferably the first counter-blade (30) has a helical development. The fixed beam is clearly visible in figures 9, 10, 16, 24 and 25.

[0100] Though a direct activation of the first roller (2) and the second roller (2’) is not to be excluded, it is common for an interfolding machine to comprise a motor (60) for the cutting roller (3) and for the first roller (2) and another motor (64) for the overlapping roller (4) and, in general, for a fourth roller (4f) and a fifth roller (5f), as well as for folding fingers (45), elements that will be discussed in the following.

[0101] This allows, in particular, a simpler and more secure management of the synchrony among the various components, as will be better illustrated in the following with reference to figures 7 and 8.

[0102] The movement means preferably comprise a motor (60), a first cogwheel (61 ) solidly constrained to the first roller (2), a second cogwheel (62) solidly constrained to the second roller (2’) and a third cogwheel (63) solidly constrained to the third roller (3). In the first arrangement (A1 ), the third cogwheel (63) engages the first cogwheel (61 ), in the second arrangement (A2) the third cogwheel (63) engages the second cogwheel (62) and the motor (60) moves the first cogwheel (61 ) and the second cogwheel (62) via the third cogwheel (63).

[0103] Owing to the coupling between the cogwheels (61 , 62, 63) the movement can be brought simply to the first cogwheel (61 ) or the second cogwheel (62).

[0104] In the example of the appended figures the at least a connection (71 , 72, 73, 74) is assimilable to sliding pairs or rotoidal couples, as parts of the plurality of parts (10, 11 , 12, 13, 14) are constrained to translate or rotate. In greater detail, in the embodiments of figures 9 and 15 the at least a connection (71 , 72, 73, 74):

[0105] - constrains the third part (13) and the part (10) in such a way that the first part (11 ) translates with respect to the part (10) and to the second part (12);

[0106] - constrains the second part (12) and another part (14) interposed between the second part (12) and the part (10) in such a way that the second part (12) translates with respect to the part (10) and to the first part (11 );

[0107] - constrains the first part (11 ) and the third part (13) in such a way that the first part (11 ) is rotatable with respect to the third part (13) and thus with respect to the part (10) and to the second part (12).

[0108] In the appended figures the other interposed part (14) has been inserted, also with the purpose of showing how the first arrangement (A1 ) and the second arrangement (A2) can depend on connections of the at least a connection (71 , 72, 73, 74) which do not directly connect two parts from among the first part (11 ), the second part (12), the third part (13) and the part (10). In the example case, the other interposed part (14) bears a fifth roller (5f) in such a way as to enable replacement and / or adjustment of the distance with respect to a fourth roller (4f) of the folding means.

[0109] As shown by way of example in figures 10 and 15, the at least a connection (71 , 72, 73, 74) preferably comprises a first connection (71 ) which limits the motion of the first part (11 ) with respect to the part (10), and thus the second part (12), along a first path (71a) and a second connection (72) which limits the motion of the second part (12) with respect to the part (10), and thus the first part (11 ), along a second path (72a).

[0110] The first connection (71 ) and the second connection (72) can, for example, be made using linear guides. For example, the linear guides can comprise a recirculating ball slide, or roller slide according to the load and the desired precision. Through the use of simple connections among the parts of the plurality of parts (10, 11 , 12, 13, 14) it is possible to guide the parts from the first arrangement (A1 ) to the second arrangement (A2) without losing important information on the original positioning so as to be able to return with ease to the first arrangement (A1 ).

[0111] More preferably, the rotation axis (X), the first rotation axis (X1 ) and the second rotation axis (X2) are parallel to a first direction (F), the first path (71a) is horizontal and orthogonal to the first direction (F) and the second path (72a) is horizontal and orthogonal to the first direction (F). The motion can take place in a direction that can more easily be freed from the components of an interfolding machine and, in general, has a limited or zero impact of the path of the paper.

[0112] The above-described translations enable operating, alternatively, the first roller (2) or the second roller (2’) with the first surface (21 ) which remains, however, in proximity of the third surface (31 ); this can require the second roller (2’) being maintained in rotation and / or can generate disturbance or interference.

[0113] The multi-format interfolding machine (100) is preferably configured in such a way that the first roller (2) is nearable and movable away from the cutting roller (3) and is configured to prevent rotation of the first roller (2) when this is moved away from the cutting roller (3). In this way it is possible to reduce energy consumption and / or wear on the components.

[0114] The at least a connection (71 , 72, 73, 74) preferably comprises a first rotatable connection (73) which makes the first part (11 ) rotatable with respect to the third part (13) about a determined rotation axis (X73) and the first rotation axis (X1 ) and the determined rotation axis (X73) are not coincident so that:

[0115] - the rotation of the first part (11 ) with respect to the third part (13) in a first direction moves the first surface (21 ) away from the third surface (31 ) from a proximal position (PP) to a moved-away position (PD) and

[0116] - the rotation of the first part (11 ) with respect to the third part (13) in a second direction, opposite the first direction, moves the first surface (21 ) towards the third surface (31 ) from the moved-away position (PD) to the proximal position (PP).

[0117] Figures 22 and 23, especially if observed together with figure 14, show by way of example the first rotatable connection (73) between the first part (11 ) and the third part (13). In figures 22 and 23, as well as not illustrating a support on the right of figure 14 that covers the first cogwheel (61), the first cogwheel (61 ) is also not represented so that it is possible to observe the first part (11 ) and the covers that cover the first cogwheel on the front side. Figure 14 shows roller bearings (98) between the first part (11 ) and the first roller (2) and a sliding bearing (76), or bushing, above the first part (11 ). Figure 14 also allows a view of the vacuum chamber.

[0118] In general, the first roller (2) is not provided with a brake or is made idle before the rotation about the determined rotation axis (X73); it follows that the first roller (2) might lose synchrony or phase with the cutting roller (3) in the moved-away position (PD). In order to prevent this from occurring, it is preferable for the multiformat interfolding machine (100) to comprise guide means configured to limit the rotation of the first roller (2) with respect to the third part (13) in the rotation of the first part (11 ) with respect to the third part (13) so that after the displacements from the proximal position (PP) to the moved-away position (PD) and from the moved- away position (PD) to the proximal position (PP) the first roller (2) has the same orientation with respect to the third part (13).

[0119] In a particularly simple embodiment, the guide means comprise a guide surface which forces the first roller (2) to follow a path.

[0120] As shown by way of example in figures 14 and 16, the guide means preferably comprise a guide (9) which comprises a profiled hole (91 ) and which is solidly constrained to the first roller (2), for example being solidly constrained to the first cogwheel (61 ). The guide means further comprise a movable pin (92) which is borne by the third part (13) and which is movable between a position in which it engages the profiled hole (91 ) and a position in which it frees the profiled hole (91 ) so as, respectively, to limit the displacement of the first roller (2) with respect to the third part (13) or to allow the rotation of the first roller (2) with respect to the first part (11 ) and to the third part (13).

[0121] As illustrated by way of example in figure 15, the guide means preferably also comprise an actuator (93) which moves the movable pin (92) between the two above-described positions. Figure 14 shows how the guide (9) is adjustable with respect to the first cogwheel (61 ), i.e. the circumferential position thereof can vary due to having two grooves.

[0122] In the case of movement of the rollers by means of cogwheels, in the proximal position (PP) the first cogwheel (61 ) engages the third cogwheel (63) and in the moved-away position (PD) the first cogwheel (61 ) and the third cogwheel (63) are disengaged. The guide means are particularly useful, as shown by way of example in the large-scale views of figures 20 and 21 in order to ensure that the first cogwheel (61 ) newly enmeshes the third cogwheel (63) in the same relative position. The larger-scale figures show two circumferences on cogs of the third cogwheel (63) which can be brought into the same position by the motor (60) while the cog of the first cogwheel (61 ) in the circle returns into the original position by action of the guide means. This also allows the coupling between the cogging. As shown by way of example in figures from 24 to 27, the at least a connection (71 , 72, 73, 74) can comprise a rotatable connection (74) which makes the first part (11 ) and the second part (12) rotatable with respect to the part (10) about an established rotation axis (X74).

[0123] Figures from 24 to 27 show how the constraints given by the rotatable connection (74) guide the first part (11 ) and the second part (12), in this case made in a single piece, along a circular trajectory: the rotatable connection (74) guides the first part (11 ) and the second part (12) so that they can be displaced along a third path (74a) from a first arrangement (A1 ) to a second arrangement (A2).

[0124] In the example embodiments of figures 24 and 25, the first cogwheel (61 ) solidly constrained to the first roller (2), the second cogwheel (62) solidly constrained to the second roller (2’), and the third cogwheel (63) are always enmeshed with one another.

[0125] However, as described in the foregoing, in order to reduce energy consumption and / or wear on the components the multi-format interfolding machine (100) is preferably configured in such a way that the first roller (2) and the second roller (2’) are movable away from the cutting roller (3) when not in use and is configured to prevent rotation of the first roller (2) and the second roller (2’) when the second roller (2’) is moved away from the cutting roller (3). The first part (11 ) and the second part (12), in alternative embodiments to those shown by way of example in figures from 24 to 27, can then be made reversibly solidly constrained or can be distinct parts so as to enable a further guided displacement from at least a further connection of the at least a connection (71 , 72, 73, 74). For example, with reference to figures 26 and 27, the first part (11 ) and the second part (12), instead of forming a single piece which rotates about the established rotation axis (X74), might both be connected rotationally to a piece that rotates about the established rotation axis (X74), with the first rotation axis (X1 ) and the second rotation axis (X2) not coinciding with the established rotation axis (X74) in a like way to the first rotatable connection (73). The embodiments of figures 24 and 25 are substantially identical to one another and are differentiated by the type of the at least an actuator (81 , 82, 83): the first actuator (81 ) is a cylinder in figure 24 and a step motor in figure 25. In figure 25 the step motor sets a cogwheel in rotation which enmeshes another cogwheel solidly constrained to the first part (11 ) and to the second part (12).

[0126] In a common embodiment, the folding means comprise folding rollers which cooperate with folding fingers (45) to fold the sheets (A) so as to realise a pack of interfolded sheets (I). The packs of interfolded sheets (I) under formation are supported by special support means. As is known to the expert in the field, in a common embodiment the support means comprise forming tables (40a), movable vertically and separating tables (40b) which are movable at least horizontally so as to be interposed between a pack of interfolded sheets (I) formed on the forming tables (40a) and the interfolded sheets (A) in arrival. It is also known to extract the packs of interfolded sheets (I) from the space beneath the interfolding unit, by means of a conveyor belt.

[0127] The folding means preferably comprise a fourth roller (4f) and a fifth roller (5f) and the frame comprises another seat (10b) which houses the fourth roller (4f), the fourth roller (4f) being rotatable with respect to the part (10) about a fourth rotation axis (X4) and a further seat (14a) which houses the fifth roller (5f), the fifth roller (5f) being rotatable with respect to the part (10) about a fifth rotation axis (X5).

[0128] Though the first arrangement (A1 ) and the second arrangement (A2) might be obtainable with a displacement of the part (10) with respect to the ground surface, it is preferable for the part (10) not to modify its position with respect to the ground surface.

[0129] The fourth roller (4f) and the fifth roller (5f) define the outlet area of the packs of interfolded sheets and, consequently, the positioning of the production line downstream. It is therefore preferable for the part (10) not to be movable with respect to the fourth roller (4f) and the fifth roller (5f).

[0130] In the example embodiments of the appended figures, as already mentioned in the foregoing, the fourth roller (4f) and the fifth roller (5f) cooperate with folding fingers (45).

[0131] The multi-format interfolding machine (100) preferably comprises one or more strip deflection rollers (99) and the second part (12) comprises one or more seats (99a), each seat of the one or more seats (99a) accommodating a respective strip deflection roller (99). The presence of strip deflection rollers (99) on the second part (12) simplifies the management of the strip (N) during the course of the format change.

[0132] The at least an actuator (81 , 82, 83) preferably comprises precision actuators, for example a precision hydraulic cylinder or a precision electric cylinder. The precision actuators might succeed in guaranteeing the necessary precision in defining the first arrangement (A1 ) and the second arrangement (A2). However, also in the case of precision actuators, the use of adjustable abutments (95) can be preferable.

[0133] The multi-format interfolding machine (100) preferably comprises adjustable abutments (95), each adjustable abutment being interposed between parts of the plurality of parts (10, 11 , 12, 13, 14). The adjustable abutments (95) are arranged so as to define the position between at least two parts of the plurality of parts (10, 11 , 12, 13, 14) in the first arrangement (A1 ) and between at least two parts of the plurality of parts (10, 11 , 12, 13, 14) in the second arrangement (A2). For example, figure 21 illustrates an adjustable abutment (95) which defines the position between the first part (11 ) and third part (13) in the first arrangement (A1 ) and figure 11 illustrates two adjustable abutments (95) which define the position between the third part (13) and the second part (12) and the position between the third part (13) and the part (10). Figure 11 and figure 14 illustrate small plates (75) which, for example, serve to limit the displacement of the roller bearings (98) generally interposed between the rollers and the plurality of parts (10, 11 , 12, 13, 14).

[0134] The adjustable abutments (95) enable adjusting, typically during testing, the relative positions among the plurality of parts (10, 11 , 12, 13, 14), with minimum variations over time, due for example to sudden changes in temperature which are typically of an insignificant entity.

[0135] As illustrated by way of example in figure 20, the adjustable abutments (95) can comprise a calibrated screw and, possibly, a hardened plate.

[0136] The invention also relates to a method for varying a format in a multi-format interfolding machine (100).

[0137] An embodiment of the method comprises steps of:

[0138] - providing a multi-format interfolding machine (100) according to the present description;

[0139] - moving parts of the plurality of parts (10, 11 , 12, 13, 14), so that the plurality of parts (10, 11 , 12, 13, 14) pass from the first arrangement (A1) to the second arrangement (A2), realising at least a displacement of the first part (11 ) and of the second part (12) with respect to the part (10), the at least a displacement being guided by the at least a connection (71 , 72, 73, 74).

[0140] Owing to the guide given by the constraining reactions of the at least a connection (71 , 72, 73, 74), the plurality of parts (10, 11 , 12, 13, 14) can be displaced repeatably into the second arrangement (A2).

[0141] The method typically also comprises the step of newly moving parts of the plurality of parts (10, 11 , 12, 13, 14), so that the plurality of parts (10, 11 , 12, 13, 14) pass from the second arrangement (A2) to the first arrangement (A1 ), realising at least a displacement of the first part (11 ) and of the second part (12) with respect to the part (10), the at least a displacement being guided by the at least a connection (71 , 72, 73, 74).

[0142] The at least a connection (71 , 72, 73, 74), enables maintaining the relations between the plurality of parts (10, 11 , 12, 13, 14) so that it is possible to return, in a simple way, to the first arrangement (A1 ).

[0143] By maintaining the relations between the plurality of parts (10, 11 , 12, 13, 14) the need to conduct preliminary operations of regulation and adjustment of each format change is eliminated.

[0144] In the step of providing, a multi-format interfolding machine (100) is preferably provided with the first part (11 ) rotating with respect to the third part (13) about the determined rotation axis (X73), as described in the foregoing, and, in the step of moving, the first part (11 ) is translated before the first part (11 ) is rotated with respect to the third part (13) about the determined rotation axis (X73).

[0145] Figures from 16 to 19 illustrate a sequence of displacements realised due to the at least a connection (71 , 72, 73, 74) from the first arrangement (A1 ) to the second arrangement (A2) and which might be repeated in reverse mode to return to the first arrangement (A1 ).

[0146] Figure 16 illustrates the first path (71a) and the second path (72a), which enable, together with the rotation of the first part (11 ) with respect to the third part (13), passing from the first arrangement (A1 ) to the second arrangement (A2). In the sequence given by way of example, the first part (11 ) is first translated along the first path (71a), and the first part (11 ) is rotated about the determined rotation axis (X73) and lastly the second part (12) is translated along the second path (72a).

[0147] In the step of supplying, a multi-format interfolding machine (100) is preferably provided in which the at least a connection (71 , 72, 73, 74) comprises a first rotatable connection (74) which makes the first part (11 ) and the second part (12) rotatable with respect to the part (10) about an established rotation axis (X74), as described in the foregoing. Further, in the step of moving, the first part (11 ) and the second part (12) are rotated about the established rotation axis (X74). The rotatable connection (74), as well as the first rotatable connection (73), can be realised with a sliding bearing or a roller bearing.

[0148] In the step of supplying, a multi-format interfolding machine (100) is provided which preferably comprises at least an actuator (81 , 82, 83) and a control unit of the at least an actuator (81 , 82, 83) and, during the step of moving, at least a signal is transmitted to the control unit which is configured, in response to the at least a signal, to command the at least an actuator (81 , 82, 83) so as to reach the second arrangement (A2).

[0149] Figures 7, 8, 24 and 25 show an example of the passage from the first arrangement (A1 ) to the second arrangement (A2) by a rotation of the first part (11 ) and of the second part (12) with respect to the established rotation axis (X74). The actuation of the first actuator (81 ) of the embodiment of figure 24 leads to the arrangement visible in figure 25 and the actuation of the first actuator (81 ) of the embodiment of figure 25 leads to the arrangement visible in figure 25, as is clarified in terms of the first roller (2), second roller (2’), third roller (3) and the overlapping roller (4) in figures 7 and 8.

[0150] Figures 7 and 8 show how the first roller (2) and the second roller (2’) are typically provided with recesses which accommodate a portion of sheet (A) after the portion of sheet has already been retained by the overlapping roller (4) with the purpose of allowing the accumulation due to the differing velocity between the first roller (2) or the second roller (2’) and the overlapping roller (4).

[0151] As is known to the expert in the field, with the aim of obtaining the overlapping represented in figure 3, it is necessary for the tangential velocity of the overlapping roller (4) with respect to the part (10) to be 2 / 3 of the tangential velocity of the second roller (2’) with respect to the second part (12) while the overlapping represented in figure 5 can be obtained with a tangential velocity of the overlapping roller (4) with respect to the part (10) which is half the tangential velocity of the first roller (2’) with respect to the first part (11 ). In the embodiments of the appended figures of the drawings the cutting roller (3) is set in rotation by the motor (60) at the same velocity as the first roller (2) and the second roller (2’) while the fourth roller (4f), the fifth roller (5f) and, via oscillators, the folding fingers (45) are set in rotation by the other motor (64) alia stessa velocity as overlapping roller (4).

[0152] The multi-format interfolding machine (100) of the present description preferably realises packs of interfolded sheets (I) in a W or Z configuration.

[0153] Consequently it is preferable for the first format (s1 ) to be a pack of W interfolded sheets interfolded in a W fashion and the second format (s2) is a pack of interfolded sheets interfolded in a Z fashion, or vice versa. As shown by way of example in figures 3 and 5:

[0154] - Z folded sheets (A), i.e. with three identical panels, or substantially identical, are generally overlapped on one panel with the successive sheet (A) and for one panel with the preceding sheet (A) (obviously excluding the end sheets (A));

[0155] - W folded sheets (A), i.e. with four identical panels, or substantially identical, are generally overlapped on two panels with the successive sheet (A) and for two panels with the preceding sheet (A) (obviously excluding the end sheets (A)).

[0156] However the multi-format interfolding machine (100) of the present description can realise other different formats (s1 , s2) of packs of interfolded sheets (I), for example with 6 panels or 8 panels, each having identical panels, or substantially identical, overlapped by half the panels with the successive sheet (A) and with the preceding sheet (A). It is understood that the above has been described by way of non-limiting example and that any constructional variants are considered to fall within the protective scope of the present technical solution, as claimed in the following.

Claims

CLAIMS1 ) A multi-format interfolding machine (100) for realising, from a strip (N), packs of interfolded sheets (I) of different formats (s1 , s2) comprising:- a frame which comprises a plurality of parts (10, 11 , 12, 13, 14);- cutting means for cutting strip (N) so as to realise a sequence of sheets (A) with each sheet (A) having a front part (Pf) and a rear part (Pr);- an interfolding unit for interfolding the sequence of sheets (A) comprising o overlapping means for superposing the sheets (A) on one another which overlapping means comprise a first roller (2) and an overlapping roller (4) and o folding means for folding overlapped sheets (A) so as to interfold the sheets (A);- movement means; and- at least a connection (71 , 72, 73, 74), each connection making parts of the plurality of parts (10, 11 , 12, 13, 14) movable with respect to one another; wherein:- the first roller (2) comprises a first surface (21 ) for accommodating sheets (A) and first retaining means (22) of sheets (A) on the first surface (21 );- the overlapping roller (4) comprises a surface (41 ) for accommodating sheets (A) and retaining means (42) of sheets (A) on the surface (41 );- a first part (11 ) of the plurality of parts (10, 11 , 12, 13, 14) comprises a first seat (11a) which houses the first roller (2) which is rotatable with respect to the first part (11 ) about a first rotation axis (X1 );- a part (10) of the plurality of parts (10, 11 , 12, 13, 14) comprises a seat (10a) which houses the overlapping roller (4) which is rotatable with respect to the part(10) about a rotation axis (X);- the movement means are configured to set the first roller (2) in rotation with respect to the first part (11 ) and the overlapping roller (4) with respect to the part (10) so that the tangential velocity of the first roller (2) is greater than the tangential velocity of the overlapping roller (4);- in a relative first position (RP) between the first roller (2) and the overlapping roller (4), the first surface (21 ) and the surface (41 ) are at a distance which enables the retaining means (42) to attract the sheets (A) onto the surface (41 ) from the first surface (21 );- the first retaining means (22) and the retaining means (42) are configured in such a way that the surface (41 ) receives the front part (Pf) of a sheet (A) before the rear part (Pr) of the preceding sheet (A), thus superposing successive sheets (A) on the surface (41 ), in the relative first position (RP); the multi-format interfolding machine (100) being characterised in that:- the overlapping means comprise a second roller (2’) which comprises a second surface (21’) for accommodating sheets (A) and second retaining means (22’) of sheets (A) on the second surface (21’);- a second part (12) of the plurality of parts (10, 11 , 12, 13, 14) comprises a second seat (12a) which houses the second roller (2’) which is rotatable with respect to the second part (12) about a second rotation axis (X2);- the movement means are configured to set the second roller (2’) in rotation with respect to the second part (12) and the overlapping roller (4) with respect to the part (10) so that the tangential velocity of the second roller (2’) is greater than the tangential velocity of the overlapping roller (4);- in a first reciprocal position (MP) between the second roller (2’) and theoverlapping roller (4), the second surface (21’) and the surface (41 ) are at a distance which enables the retaining means (42) to attract the sheets (A) onto the surface (41 ) from the second surface (21’);- the second retaining means (22’) and the retaining means (42) are configured in such a way that the surface (41 ) receives the front part (Pf) of a sheet (A) before the rear part (Pr) of the preceding sheet (A), thus superposing successive sheets (A) on the surface (41 ), in the first reciprocal position (MP);- the first retaining means (22) are configured for a first format (s1 ) and the second retaining means (22’) are configured for a second format (s2) different to the first format (s1 ); and- the at least a connection (71 , 72, 73, 74) is configured in such a way that the first part (11 ) and the second part (12) are movable with respect to the part (10) and in such a way as to guide the plurality of parts (10, 11 , 12, 13, 14) from a first arrangement (A1 ) of the plurality of parts (10, 11 , 12, 13, 14), in which the first roller (2) occupies a volume (V) and is in the relative first position (RP) and the second roller (2’) frees the volume (V), to a second arrangement (A2) of the plurality of parts (10, 11 , 12, 13, 14), in which the first roller (2) frees the volume (V) and the second roller (2’) occupies the volume (V) and is in the first reciprocal position (MP), so as to realise a first format (s1 ) in the first arrangement (A1 ) and a second format (s2), different to the first format (s1 ), in the second arrangement (A2).2) The multi-format interfolding machine (100) of the preceding claim, comprising at least an actuator (81 , 82, 83), each actuator displacing, among themselves, parts of the plurality of parts (10, 11 , 12, 13, 14), wherein the at least an actuator (81 , 82, 83) is configured to bring the plurality of parts (10, 11 , 12, 13,14) from the first arrangement (A1 ) to the second arrangement (A2) and / or from the second arrangement (A2) to the first arrangement (A1 ).3) The multi-format interfolding machine (100) of claim 1 or 2, wherein the first roller (2), in the first arrangement (A1 ), and the second roller (2’), in the second arrangement (A2), are arranged with respect to the part (10) in such a way as to transfer the front part (Pf) of the sheets (A) to a same inlet area (In).4) The multi-format interfolding machine (100) of any one of the preceding claims, wherein:- the first rotation axis (X1 ) in the first arrangement (A1 ) and the second rotation axis (X2) in the second arrangement (A2) have the same position with respect to the part (10);- the first roller (2) and the second roller (2’) have or substantially have the same outer diameter;- the first retaining means (22) subdivide the first surface (21 ) in a first number of portions which define angles of circumference (alfa) that are equal to one another, or substantially equal to one another, with each portion retaining a sheet (A);- the second retaining means (22’) subdivide the second surface (2T) in a second number of portions which define angles of circumference (alfa) that are equal to one another, or substantially equal, to one another, with each portion retaining a sheet (A); and- the second number is different to the first number.5) The multi-format interfolding machine (100) of any one of the preceding claims, wherein:- the cutting means comprise a first counter-blade (30), or blade, and a cutting roller (3) which comprises a third surface (31 ) for accommodating sheets (A), thirdretaining means (32) of strip and / or sheets (A) on the first surface (31 ) and at least a blade (33), or counter-blade, which cooperates with the first counter-blade (30), or blade, to cut the strip (N) so as to realise the sequence of sheets (A);- a third part (13) of the plurality of parts (10, 11 , 12, 13, 14) comprises a third seat (13a) which houses the cutting roller (3) which is rotatable with respect to the third part (13) about a third rotation axis (X3);- the movement means are configured to set the cutting roller (3) in rotation with respect to the third part (13) and the first roller (2) with respect to the first part (11 ) so that the tangential velocity of the cutting roller (3) is equal to the tangential velocity of the first roller (2);- the movement means are configured to set the cutting roller (3) in rotation with respect to the third part (13) and the second roller (2’) with respect to the second part (12) so that the tangential velocity of the cutting roller (3) is equal to the tangential velocity of the second roller (2’);- in the first arrangement (A1 ), the first surface (21 ) and the third surface (41 ) are at a distance which enables the first retaining means (22) to attract the sheets (A) onto the first surface (21 ) from the third surface (31 );- in the second arrangement (A2), the second surface (21’) and the third surface (41 ) are at a distance which enables the second retaining means (22’) to attract the sheets (A) onto the second surface (21’) from the third surface (31 );- the cutting means are configured to cut sheets (A) of a first length (L1 ) or, alternatively, of a second length (L2);- the first retaining means (22) are configured for sheets (A) of the first length (L1 ), so as to obtain the first format (s1 );- the second retaining means (22’) are configured for sheets (A) of the secondlength (L2), so as to obtain the second format (s2).6) The multi-format interfolding machine (100) of the preceding claim, wherein the movement means comprise a motor (60), a first cogwheel (61 ) solidly constrained to the first roller (2), a second cogwheel (62) solidly constrained to the second roller (2’) and a third cogwheel (63) solidly constrained to the third roller (3), wherein in the first arrangement (A1 ) the third cogwheel (63) engages the first cogwheel (61 ), wherein in the second arrangement (A2) the third cogwheel (63) engages the second cogwheel (62) and wherein the motor (60) moves the first cogwheel (61 ) and the second cogwheel (62) via the third cogwheel (63).7) The multi-format interfolding machine (100) according to any one of the preceding claims, wherein the at least a connection (71 , 72, 73, 74) comprises a first connection (71 ) which limits the motion of the first part (11 ) with respect to the part (10) along a first path (71a) and a second connection (72) which limits the motion of the second part (12) with respect to the part (10) along a second path (72a).8) The multi-format interfolding machine (100) according to the preceding claim wherein the rotation axis (X), the first rotation axis (X1 ) and the second rotation axis (X2) are parallel to a first direction (F), the first path (71a) is horizontal and orthogonal to the first direction (F) and the second path (72a) is horizontal and orthogonal to the first direction (F).9) The multi-format interfolding machine (100) of claim 7 or 8, wherein:- the at least a connection (71 , 72, 73, 74) comprises a first rotatable connection (73) which makes the first part (11 ) rotatable with respect to the third part (13) about a determined rotation axis (X73);- the first rotation axis (X1 ) and the determined rotation axis (X73) are notcoincident, so that the rotation of the first part (11 ) with respect to the third part (13) in a first direction moves the first surface (21 ) away from third surface (31 ) from a proximal position (PP) to a moved-away position (PD) and in that the rotation of the first part (11 ) with respect to the third part (13) in a second direction, opposite the first direction, nears the first surface (21 ) to the third surface (31 ) from the moved-away position (PD) to the proximal position (PP).10) The multi-format interfolding machine (100) of claim 9, comprising guide means configured to limit the rotation of the first roller (2) with respect to the third part (13) in the rotation of the first part (11 ) with respect to the third part (13) so that after the displacements from the proximal position (PP) to the moved-away position (PD) and from the moved-away position (PD) to the proximal position (PP) the first roller (2) has the same orientation with respect to the third part (13).11) The multi-format interfolding machine (100) of claim 9 or 10, with claim 7 or claim 8 dependent on claim 6, wherein in the proximal position (PP) the first cogwheel (61 ) engages the third cogwheel (63) and in the moved-away position (PD) the first cogwheel (61 ) and the third cogwheel (63) are disengaged.12) The multi-format interfolding machine (100) of any one of claims from 1 to 6 wherein the at least a connection (71 , 72, 73, 74) comprises a rotatable connection (74) which makes the first part (11 ) and the second part (12) rotatable with respect to the part (10) about an established rotation axis (X74).13) The multi-format interfolding machine (100) according to any one of the preceding claims, wherein the folding means comprise a fourth roller (4f) and a fifth roller (5f) and the frame comprises another seat (10b) which houses the fourth roller (4f) which is rotatable with respect to the part (10) about a fourth rotation axis (X4) and a further seat (14a) which houses the fifth roller (5f) which is rotatablewith respect to the part (10) about a fifth rotation axis (X5).14) The multi-format interfolding machine (100) of any one of the preceding claims, comprising one or more strip deflection rollers (99) wherein the second part (12) comprises one or more seats (99a), each seat of the one or more seats (99a) accommodating a respective strip deflection roller (99).15) The multi-format interfolding machine (100) according to any one of the preceding claims comprising adjustable abutments (95), each adjustable abutment being interposed between parts of the plurality of parts (10, 11 , 12, 13, 14), wherein the adjustable abutments (95) are arranged so as to define the position between at least two parts of the plurality of parts (10, 11 , 12, 13, 14) in the first arrangement (A1 ) and between at least two parts of the plurality of parts (10, 11 , 12, 13, 14) in the second arrangement (A2).16) A method for varying a format in a multi-format interfolding machine (100) comprising steps of:- providing a multi-format interfolding machine interfolding machine (100) according to any one of the preceding claims;- moving parts of the plurality of parts (10, 11 , 12, 13, 14), so that the plurality of parts (10, 11 , 12, 13, 14) pass from the first arrangement (A1) to the second arrangement (A2), realising at least a displacement of the first part (11 ) and of the second part (12) with respect to the part (10), the at least a displacement being guided by the at least a connection (71 , 72, 73, 74).17) The method of claim 16, wherein, in the step of providing, a multi-format interfolding machine (100) is provided according to claim 9 or according to one of the claims dependent thereon and wherein, in the step of moving, the first part (11 ) is translated before the first part (11 ) is rotated with respect to the third part (13)about the determined rotation axis (X73).18) The method of claim 16, wherein, in the step of providing, a multi-format interfolding machine (100) is provided according to claim 12 or according to one of the claims dependent thereon and wherein, in the step of moving, the first part (11 ) and the second part (12) are rotated about the established rotation axis (X74).19) The method of any one of claims from 16 to 18, wherein the first format (s1 ) is a pack of W interfolded sheets interfolded in a W fashion and the second format (s2) is a pack of interfolded sheets interfolded in a Z fashion, or vice versa.

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