Machine for forming a rod of the tobacco industry and a related forming method

Abstract

A machine (1) for forming a rod of the tobacco industry, wherein the machine (1) comprises: a feeding unit (5) which feeds a material web (N) having a first orientation; a stabilizing unit (6) arranged downstream of the feeding unit (5) and comprising at least one stabilizing module (10) configured to perform a temporary twist of the material web (N) about its longitudinal axis, parallel to the longitudinal extension (L) in such a way as to stabilize the advancement of the material web (N) Each stabilizing module (10) comprises at least two stabilizing elements (11; 11A, 11B; 11C, 11D) arranged in succession one behind the other along the advancement direction (DA) of the material web (N) and each configured to perform a respective temporary twist. A forming unit (15) configured to collect the material web (N) and to wrap the collected material web (N) with a further material web (N) so as to form the rod.

Description

[0001] " MACHINE FOR FORMING A ROD OF THE TOBACCO INDUSTRY AND A RELATED FORMING METHOD"

[0002] Cross-Reference to Related Applications

[0003] This Patent Application claims priority from Italian Patent Application No.

[0004] 102024000024297 filed on October 30, 2024, the entire disclosure of which is incorporated herein by reference.

[0005] Technical Field

[0006] The present invention relates to a machine for forming a rod of the tobacco industry and to a related forming method.

[0007] The invention is advantageously, but not exclusively, applied to the feeding of a material web to the forming machine, wherein the material web is picked up from a bale.

[0008] Preferably, but not exclusively, the material of the material web is one chosen from (non-exhaustive list): paper, non-woven fabric material or an aerosolforming substrate.

[0009] Prior Ar

[0010] In the tobacco industry, in particular in the field of machines for forming rods, a filler material (preferably a webbed material or a shredded material, in particular tobacco) is typically fed, which is subsequently collected in a forming unit, so as to form the strand of filler material and which is subsequently wrapped by a (preferably paper-based) wrapping material so as to obtain the rod of material. The feeding of a web-shaped material (in particular of the filler material and / or of the wrapping material) occurs by unwinding the material from a reel or from a bale of material.

[0011] The currently known machines for forming the rod (e.g. filtering rod or aerosol generating rod) have the disadvantage that the material web at the inlet sways transversely, in particular with respect to its longitudinal extension (i.e. to its feeding direction). In other words, the fed material drifts laterally at the inlet of the machine for forming the rod.

[0012] Therefore, there is the need to stabilize the material web upstream of the inlet in the machine for forming the rod.

[0013] A device and a method for temporarily storing a material web are known from document US2003094181A1. Whereas, a device and a method for feeding a wrapping material web in the machines for forming a rod of the tobacco industry are known from document CN1226407A.

[0014] Description of the Invention

[0015] The object of the present invention is to provide a machine for forming a rod of the tobacco industry and a related forming method which are at least partially devoid of the drawbacks described above and are easy and cost-effective to manufacture and implement.

[0016] In accordance with the present invention, a machine for forming a rod is provided, according to what is claimed in the appended claims.

[0017] Furthermore, with the present invention, a forming method for forming a rod is provided, according to what is claimed in the appended claims.

[0018] The claims describe preferred embodiments of the present invention forming integral part of the present description.

[0019] Brief Description of the Drawings

[0020] The present invention will now be described with reference to the accompanying drawings, which illustrate non-limiting embodiments thereof, wherein:

[0021] Figure 1 schematically shows a bale of material;

[0022] Figure 2 is a side schematic view (with some parts removed for clarity) of a machine for forming a rod according to a possible first embodiment of the present invention;

[0023] Figure 3 is a front schematic view of the forming machine of Figure 2; Figure 4 is an enlarged schematic view of a part of Figure 3;

[0024] Figure 5 is an enlarged schematic view of an alternative embodiment of a part of Figure 4;

[0025] Figure 6 is a side schematic view (with some parts removed for clarity) of a machine for forming a rod according to a possible further and different embodiment of the present invention;

[0026] Figure 7 is a possible variant of the machine of Figure 6;

[0027] Figure 8 is a side schematic view (with some parts removed for clarity) of a machine for forming a rod according to a possible further and different embodiment of the present invention;

[0028] Figure 9 is a front schematic view of the forming machine of Figure 8; Figure 10 is a top schematic view of the forming machine of Figures 8 and 9;

[0029] Figure 11 is a side schematic view (with some parts removed for clarity) of a machine for forming a rod according to a possible additional and different embodiment of the present invention; and

[0030] Figure 12 is a top schematic view of the forming machine of Figure 11.

[0031] Preferred Embodiments of the Invention

[0032] In Figures 2-12, reference numeral 1 indicates, as a whole, a machine for forming a rod of the tobacco industry, in particular for producing a sub-unit of a smoking article.

[0033] According to a possible (non-limiting) embodiment, the machine 1 is a machine for producing filters, configured to produce at least one segment of a filter (subunit) of the smoking article.

[0034] According to a possible alternative embodiment, the machine 1 is a machine for producing at least one segment (sub-unit) comprising tobacco or any substrate for generating aerosol.

[0035] Preferably the sub-unit is obtained by cutting the continuous rod of material produced by the machine 1.

[0036] The material web N (indicated in grey in the accompanying figures) fed to the machine 1 is picked up from a support S. The support S can be a reel (not illustrated) or a bale 2 (an example of which is schematically illustrated in Figure 1, without losing generality) of material used in the tobacco industry. In particular, the bale 2 comprises the material web N arranged either neatly (as is illustrated in Figure 1) or haphazardly (i.e. arranged in bulk, confusedly, without order or distinction, as is the case for example in the bales of filter material, such as for example cellulose acetate).

[0037] Advantageously, but not limitedly, the bale 2 comprising the neatly arranged material web N comprises, in turn, at least one stack 3 which is schematically illustrated in Figure 1. In the case where the stacks 3 are more than one, the stacks 3 are arranged side by side parallel to a longitudinal extension L of the material web N of each stack 3. The material web N is a continuous web. The material web N of each stack 3 comprises a plurality di folds (defined by folding lines 4), which extend transverse, in particular orthogonal, to the longitudinal extension L of the material web N. Each fold is made in opposite and alternating folding directions DP, so that two successive layers obtained by folding the web N are parallel to each other. In other words, the web N is folded in a “zig-zag” manner. Two successive layers of material N obtained by folding the material web N are superimposed on each other. Preferably, the at least one stack 3 of material web N is supported by (in particular is arranged on) the transporting support S. In particular, in the case of the bale 2, the support S is flat and is a pallet.

[0038] The material web N is moved longitudinally along an advancement path PA defined between an inlet station SI, at which the material web N enters the machine 1, and an outlet station Sil at which the continuous rod of material exits the machine 1. The advancement path PA defines an advancement direction DA of the web-shaped material N. The advancement direction DA has an advancement direction which goes from the inlet station SI to the outlet station Sil.

[0039] The machine 1 comprises a feeding unit 5, a stabilizing unit 6 and a forming unit 15.

[0040] The two units 5 and 6 are substantially arranged in proximity to the inlet station SI of the machine 1 and are arranged in succession one behind the other. In particular, the two units 5 and 6 are arranged astride the inlet station SI. Possibly, the feeding unit 5 is arranged upstream of the inlet station SI; whereas, the stabilizing unit 6 is arranged downstream of the inlet station SI. Alternatively, both units 5 and 6 are arranged upstream of the inlet station SI.

[0041] The feeding unit 5 is configured to feed the material web N having a longitudinal extension L and having a first orientation.

[0042] The stabilizing unit 6 is arranged downstream of the feeding unit 5 and comprising at least one stabilizing module 10 configured to perform a temporary twist (in particular of the angle a, more in particular a1 and a2 or a3 and a4, as is described in detail in the following) of the material web N about its longitudinal axis, parallel to the longitudinal extension L in such a way as to stabilize the advancement of the material web N.

[0043] Each stabilizing module 10 comprises at least two stabilizing elements 11 (in particular 11 A, 11 B and / or 11C, 11 D) arranged in succession one behind the other along the advancement direction DA of the web N.

[0044] The first stabilizing element 11 (in particular the element 11 A or 11 C) is designed and configured to cause a first twist of the material web N about its longitudinal axis by a first angle a1 (or a3), such that the material web N has a longitudinal extension L extending with a second orientation (which in the figures is illustrated angled or parallel to the plane of the sheet of Figures 2, 6-8 and 11) that is transverse (Figures 6, 7 and 11), preferably orthogonal (Figures 2, 6-8 and 11 ), to the first orientation.

[0045] The second stabilizing element 11 (in particular the element 11 B or 11 D) is designed and configured to cause a second twist of the material web N about its longitudinal axis by a second angle a2 (or a4), such that the material web N has a longitudinal extension L extending with an orientation that is different from the second orientation.

[0046] In particular, the second twist of the web N is carried out with a direction of rotation that is equal to or opposite the direction of rotation of the first twist. Additionally or alternatively, the second twist of the web N is carried out with an angle a2 having an absolute value equal to or different from the absolute value of the angle a1.

[0047] Advantageously, the angle a (namely the angles a1 and a2, but also the angles a3 and a4 described in the following) is comprised between 60° and 120°, in particular between 80° and 100°, preferably equal to 90°.

[0048] Therefore, downstream of the second twist, the web N can have:

[0049] - (again) the first orientation: in the case where the absolute values of the two angles a1 and a2 are equal and the direction of rotation of the second twist is opposite the direction of rotation of the first twist. In this case, the tensioning of the material web N upstream and downstream of the respective stabilizing module 10 is of equal magnitude (but with opposite direction); or

[0050] - an orientation different from both the first orientation and the second orientation. This occurs for example in the case where at least one of the absolute value of the two angles a1 and a2 (regardless of the direction of rotation) and / or the direction of rotation of the second twist with respect to the direction of rotation of the first twist is equal. In particular, for example if the two angles both have the same absolute value (such as for example 90°) and the direction of rotation is the same, downstream of the second twist, the web N would have a third orientation, i.e. would be overturned (in particular rotated by 180°) with respect to the first orientation.

[0051] In particular, the term “orientation” means the relative orientation of the plane in which the material web N lies along the advancement path PA with respect to a vertical plane of the machine 1, which extends parallel to the advancement path PA.

[0052] In particular, in the following discussion, the term “first orientation” means the orientation of the material web N arranged orthogonal to the vertical plane as previously defined (in particular, with reference to Figures 2, 6-8 and 11, it means the orientation of the material web N orthogonal to the plane of the sheet of the figures); whereas, the term “second orientation” means the orientation of the material web N arranged at an angle (i.e. inclined and not orthogonal) or parallel to the vertical plane (in particular, with reference to Figures 2, 6-8 and 11, it means the orientation of the material web N at an angle or parallel to the plane of the sheet of the figures).

[0053] The term “stabilization” means the elimination of (or anyway the significant reduction in) the lateral movement of the web N during its advancement. In particular, it means that the web N advances along a direction parallel to its longitudinal extension and does not have lateral movements, i.e. transverse (orthogonal) with respect to its longitudinal extension. In other words, the term “stabilization” means that the advancement of the web N has only one advancement component parallel to the longitudinal extension of the web N. Such “stabilization” is made possible thanks to the temporary twist of the web N by means of the stabilizing elements 11. In particular, such stabilization is due to geometrical factors and / or to a tensioning of the web N defined by the stabilizing elements 11.

[0054] The forming unit 15, which is arranged in particular downstream of the units 5 and 6, is configured to form the rod with the material web N, wherein the material web N is a filler material or a wrapping material.

[0055] According to a possible embodiment, the machine 1 comprises more feeding units 5 each configured to feed a respective material web N (for example different from one another) and more stabilizing units 6 each configured to stabilize the respective material web N. In such case, by way of example, both the filler material web N, and the wrapping material web N are subjected to a stabilization (by the unit 6) upstream of the forming unit 15.

[0056] Preferably, the material web N comprises (in particular is made of) a material chosen among (non-exhaustive list):

[0057] a filler material: a non-woven fabric and / or paper and / or a filtering material (for example cellulose acetate-based or material for NWA filters (also known as non-wrapped acetate filters) and / or an aerosol-forming substrate (such as, for example, tobacco with or without additives); or

[0058] a wrapping material of the rod (for example paper-based); or

[0059] any web-shaped material used in the tobacco industry.

[0060] According to the illustrated embodiment (which is not limiting), the feeding unit 5 comprises a feeding head 7 configured to pick up the material web N from the support S. Advantageously, the feeding head 7 is carried by an arm 8 (described in detail in the following). The feeding head 7 preferably comprises a plurality of feeding elements 9 (in particular in the accompanying figures the elements 9 are seven). Preferably, but not necessarily, the feeding elements 9 are rollers, which are configured to rotate around a respective axis X1, in particular horizontal, so as to make the web N advance in the advancement direction DA towards the stabilizing unit 6. At the feeding head 7 and thus at the feeding elements 9, the material web N has the first orientation.

[0061] Downstream of the feeding elements 9, the stabilizing elements 11 are arranged. Advantageously, but not limitedly, the stabilizing elements 11 are for example pins, sliding blocks (in particular provided with air blows for reducing the friction) or rollers (which also exert a reduced friction with the web N).

[0062] In particular, in the following discussion (without losing generality) reference will be explicitly made to the embodiment wherein the stabilizing elements 11 are rollers. The stabilizing rollers 11 are provided with a respective axis X2. In particular, in the embodiment illustrated in the accompanying figures, the axis X2 is a rotation axis around which the stabilizing elements 11 are configured to rotate. In the case where the elements 11 are not rollers, the axis X2 is a generic axis.

[0063] Advantageously, the two stabilizing elements 11 are arranged in proximity to each other and the axes X2 lie on two vertical planes which are parallel to each other. In particular, as is described in the following, the two vertical planes are spaced apart by a distance D1 (as is illustrated in Figures 3 and 4) or are coplanar (as is illustrated in Figure 5).

[0064] Preferably, the axes X2 are parallel to each other. The at least two stabilizing elements 11 (in particular the elements 11 A, 11 B and / or the elements 11 C, 11 D) are arranged in succession one behind the other (along the advancement direction DA of the material web N).

[0065] Preferably, the stabilizing unit 6 comprises at least two deflection elements 12 (i.e. a plurality of deflection elements 12). The stabilizing elements 11 are arranged between the at least two deflection elements 12.

[0066] Advantageously, but not limitedly, the deflection elements 12 are for example pins, sliding blocks (in particular provided with air blows for reducing the friction) or rollers (which also exert a reduced friction with the web N).

[0067] In particular, in the following discussion (without losing generality) reference will be explicitly made to the embodiment wherein the deflection elements 12 are rollers. Each deflection roller 12 is provided with a respective axis X3, in particular horizontal. In particular, in the embodiment illustrated in the accompanying figures, the axis X3 is a rotation axis around which the deflection elements 12 are configured to rotate. In the case where the deflection elements 12 are not rollers, the axis X3 is a generic axis.

[0068] The stabilizing elements 11 are arranged between the at least two deflection elements 12. The deflection elements 12 are configured to guide the material web N along the advancement path PA. Each axis X3 of the deflection elements 12 is transverse, in particular orthogonal, to the axis X2 of the stabilizing elements 11. Advantageously, in the embodiment of Figures 2-5, the two axes X3 of the at least two deflection elements 12 are arranged on the same vertical plane or on two distinct vertical planes (as described in the following). The axes X2 of the at least two stabilizing elements 11 are arranged horizontally (in particular orthogonal to the axes X3). As is evident in Figure 3 which shows a front view (with some parts removed for clarity), the material web N has a first relative axial position, with respect to the axis X3’ of the deflection element 12 (arranged upstream of the other element 12), which is aligned with a second relative axial position, with respect to the axis X3” of the deflection element 12 (arranged downstream of the other element 12). In other words, as is illustrated in Figure 3, the twist of the web N does not deviate transversely, in particular orthogonally, with respect to the longitudinal extension L (namely said relative axial position with respect to the axis X3) the path of the material web N. In particular, as is illustrated in detail in Figure 2, the axes X3’ and X3” of the deflection elements 12 are coplanar and lie on a same vertical plane.

[0069] The two stabilizing elements 11 (i.e. the elements 11 A and 11 B or 11 C and 11 D) are arranged in proximity to each other and the axes X2 of the two stabilizing elements 11 lie on two vertical planes which are parallel to each other. The axes X2 are coplanar (as is illustrated in Figure 5) or are spaced apart from each other by the distance D1 (as is illustrated in the enlargement of Figure 4). In this case, the distance D1 identifies in substance the horizontal distance between centres of the two elements 11. Preferably, the distance D1 is equal to the sum of the two radiuses of the elements 11A and 11 B, such that the material is tangentially guided to the respective elements 11 A and 11 B as is illustrated in detail in Figure 4.

[0070] In the solution of Figure 4, the two stabilizing elements 11 are arranged in proximity to each other, in particular are almost tangent to each other. As is illustrated in Figure 3, therefore also in this embodiment, thanks to the arrangement of the stabilizing elements 11 with respect to the deflection elements 12, the twist of the web N does not deviate the path of the material web N transversely, in particular orthogonally, with respect to the longitudinal extension L (namely said relative axial position with respect to the axis X3). According to a possible alternative (illustrated in detail in Figure 5) of the solution illustrated in Figure 4, the stabilizing unit 6 (in particular the stabilizing module 10) comprises a deviation element 13 of the material web N. Advantageously, but not limitedly, the deviation element 13 can be for example a pin, a sliding block (in particular provided with air blows for reducing the friction) or a roller (which also exerts a reduced friction with the web N).

[0071] In particular, in the following discussion (without losing generality) reference will be explicitly made to the embodiment wherein the deviation element 13 is a roller. The deviation roller 13 is provided with a respective axis X4, which is in particular parallel to the axes X2. In particular, in the embodiment illustrated in Figure 5, the axis X4 is a rotation axis around which the stabilizing element 11 is configured to rotate. In the case where the deviation element 13 is not a roller, the axis X4 is a generic axis.

[0072] In order to allow the elements 11A and 11 B to stabilize the web N, which as illustrated in Figure 5 could be vertically tangent to the respective stabilizing element 11 at the same side of the roller, i.e. on the left in the aforementioned figure, the deviation element 13 is interposed (in the advancement path PA of the web N) between the at least two stabilizing elements 11 A and 11 B. The element 13 thus allows controlling the twist of the web N for creating the stabilizing effect. In Figure 5 (which is not limiting) the axes X2 of the two stabilizing elements 11 are preferably (but not necessarily) coplanar on the same vertical plane (different from the vertical plane in which the axes X3 lie) and are spaced apart from each other by a distance D2 (indicated in the enlargement of Figure 5 and which identifies in substance the distance between centres of the two elements 11 along a direction orthogonal to the direction in which the distance D1 is measured, i.e. the distance D2 is measured vertically). According to a possible alternative (not illustrated), the axes X2 of the two stabilizing elements 11 are also spaced apart by the distance D1 as described above.

[0073] The axis X4 of the deviation element 13 is arranged on a vertical plane which is parallel to and spaced apart by a distance D3 (indicated in the enlargement of Figure 5 and measured along a direction parallel to the direction in which the distance D1 is measured, i.e. the distance D3 is measured horizontally) from the planes, in particular the plane, in which each axis X2 of the two stabilizing elements 11 lie, in particular of the same stabilizing module 10. Also in this case, thanks to the arrangement of the stabilizing elements 11 with respect to the deflection elements 12, the twist of the web N does not deviate the path of the material web N transversely, in particular orthogonally, with respect to the longitudinal extension L (namely said relative axial position with respect to the axis X3) downstream of the stabilizing element 11 B.

[0074] The following describes an embodiment illustrated for example in Figures 8-10, which differs from the embodiment illustrated in Figures 2-4 in the arrangement of the stabilizing elements 11. In fact, in this embodiment, the axes X2 of the two stabilizing elements 11 are arranged substantially vertically. In this case, following the vertical arrangement of the axes X2 of the stabilizing elements 11, maintaining the axes X3 of the deflection elements 12 horizontal, the material web N has a first relative axial position, with respect to the axis X3’ of the first deflection element 12, which is misaligned (by an amount substantially equal to the width of the web N, i.e. to the measure measured orthogonal to its longitudinal extension L) at a second relative axial position, with respect to the axis X3” of the second deflection element 12. Preferably, at the axis X3’ two first deflection elements 12 are arranged which are independent of each other. In particular, the axes X3’ and X3” of the deflection elements 12 lie on the same vertical plane and are vertically spaced apart from each other by a distance D4 (schematically indicated in Figure 9 and measured parallel to the longitudinal extension L of the web N); whereas, the axes X2 of the two stabilizing elements 11 (in particular the elements 11 A and 11 B of Figure 9) are arranged on two vertical planes which are parallel to and spaced apart from each other by a distance D5 (indicated in Figure 8 and which defines the distance between centres of the two axes X2). In other words, the axes X3’ and X3” of the deflection elements 12 lie on two horizontal planes which are parallel to and vertically spaced apart from each other by the distance D4 (measured as indicated above) and the axes X2 of the two stabilizing elements 11 are coplanar on the same vertical plane and are spaced apart from each other by a distance D5 (measured transverse, in particular orthogonal, to the distance D4). In particular, in this case the axis X3” has a secondary in particular negligible effect on the stabilization of the web N.

[0075] Advantageously, but not limitedly, as is schematically illustrated in Figures 8 and 9, the stabilizing module 10 is arranged in the part of the machine 1 arranged at the bottom. This embodiment allows exploiting the lower part of the machine 1 which is typically empty. In the upper part (i.e. above the stabilizing module 10) possible units of the machine 1 are arranged, such as for example a machining unit 14 and / or the forming unit 15, mentioned in the following.

[0076] In accordance with a further and different embodiment, illustrated in Figure 6, the stabilizing unit 6 comprises at least two deflection elements 12, both arranged at the feeding head 7. The stabilizing elements 11 are interposed between the two deflection elements 12 (in the advancement path PA) and are arranged outside the feeding head 7. In other words, the stabilizing elements 11 are not arranged at the feeding head 7. The two deflection elements 12 have a respective axis X3 which is transverse to the axis X2 of the stabilizing elements 11. In this case, following the arrangement of the axes X2 of the stabilizing elements 11, maintaining the axes X3 of the deflection elements 12 horizontal, the material web N has a first relative axial position, with respect to the axis X3’ of the first deflection element 12, which is misaligned (by an amount substantially equal to the width of the web N) at a second relative axial position, with respect to the axis X3” (which is coaxial to the axis X3’) of the second deflection element 12.

[0077] Advantageously, according to what is illustrated in Figure 6, the stabilizing elements 11 are arranged integral with the arm 8 of the feeding unit 5.

[0078] According to a possible variant of Figure 6, schematically illustrated in Figure 7, the stabilizing elements 11 are arranged in proximity to the lower element 12 of Figure 2. In this case, when the arm 8 is in a lowered position (described in the following), the operator must thread the web N between the stabilizing elements 11 during the positioning of the feeding head 7 in a raised position (also described in the following).

[0079] According to an additional embodiment, the previously described embodiments are combined with one another, in such a way as to perform more temporary twists. In other words, the stabilizing unit 6 can comprise more stabilizing modules 10.

[0080] Advantageously, according to the embodiment illustrated in Figures 11 and 12, the stabilizing unit 6 comprises at least two stabilizing modules 10. The first stabilizing module 10A performs two first temporary twists; one of a first angle a1 and the other of a second angle a2. The second stabilizing module 10B performs two second temporary twists, one of a third angle a3 and the other of a fourth angle a4.

[0081] Advantageously, the absolute values of at least two of: the angles a1, a2, a3 and a4 are equal to each other and / or the absolute values of at least two of: the angles a1, a2, a3 and a4 are different from each other. Additionally or alternatively, the direction of rotation of the temporary twists of at least two of the angles a1, a2, a3 and a4 are equal to or opposite each other.

[0082] According to a preferable embodiment (which is not limiting), the stabilizing module 10A performs two first temporary twists of an angle a1 and a2 having equal absolute values, but with opposite directions; whereas, the stabilizing module 10B performs two second temporary twists of an angle a3 and a4 having equal absolute values, but with opposite directions. The absolute value of the angles a1 and a2 is equal to or different from the absolute value of the angles a3 and a4.

[0083] According to the embodiment illustrated in Figures 11 and 12 (which is a combination of the embodiments of Figures 2-6), each stabilizing module 10 comprises at least two stabilizing elements 11 and at least two deflection elements 12 provided with the respective horizontal axis X3, which is transverse to the axis X2 of the stabilizing elements 11. The stabilizing module 10A comprises two of the four deflection elements 12, arranged at the feeding head 7. The stabilizing elements 11A and 11B are interposed between the two deflection elements 12 (in the advancement path PA) and are arranged outside the feeding head 7. In other words, similar to Figure 6, the stabilizing elements 11 A and 11 B are not arranged at the feeding head 7. In this case, following the arrangement of the axes X2 of the stabilizing elements 11, maintaining the axes X3 of the deflection elements 12 horizontal, the material web N has a first relative axial position, with respect to the axis X3’ of the first deflection element 12, which is misaligned (by an amount substantially equal to the width of the web N) at a second relative axial position, with respect to the axis X3” (which is coaxial to the axis X3’) of the second deflection element 12. The second stabilizing module 10B comprises the two stabilizing elements 11C and 11 D interposed between the other two of the four deflection elements 12. In particular, the two axes X3 of the at least two deflection elements 12 of the module 10B are arranged on the same vertical plane and the axes X2 of the at least two stabilizing elements 11 are arranged horizontally (in particular orthogonal to the axes X3 of the stabilizing elements 11). At the second stabilizing module 10, the material web N has a first relative axial position, with respect to the axis X3’ of the deflection element 12 (arranged upstream of the other element 12), which is aligned at a second relative axial position, with respect to the axis X3” of the deflection element 12 (arranged downstream of the other element 12). In other words, the twist of the web N performed by the module 10B does not deviate transversely, in particular orthogonally, with respect to the longitudinal extension L (namely said relative axial position with respect to the axis X3) the path of the material web N. However, the twist of the web N performed by the module 10A deviates transversely, in particular orthogonally, with respect to the longitudinal extension L (namely said relative axial position with respect to the axis X3) the path of the material web N, as is illustrated in Figure 12.

[0084] Advantageously, but not limitedly, according to what is illustrated in the accompanying figures,

[0085] the support S (in particular the bale 2) from which the feeding unit 5 picks up the material web N is arranged such that the longitudinal extension L of the web N of each stack 3 upstream of the feeding head 7 is arranged transverse, in particular orthogonal, to the advancement path PA of the web N in the machine 1. In this manner it is possible to perform a further temporary twist by an angle β before feeding the web N to the feeding head 7 in such a way as to further increase the stability of the material web N. In other words, the feeding head 7 is configured to receive the material web N with an orientation that is different from the first orientation and the support S is arranged with respect to the feeding head 7 in such a way as to make a preliminary twist of the material web N about its longitudinal axis, parallel to the longitudinal extension L, by the angle β. The absolute values of at least two of the angles a1 and / or a2 and / or β are equal to or different from each other.

[0086] Advantageously, but not limitedly, according to an embodiment not illustrated, the support S (in particular the bale 2) from which the feeding unit 5 picks up the material web N is arranged such that the longitudinal extension L of the web N of each stack 3 upstream of the feeding head 7 is arranged parallel to the advancement path PA of the web N in the machine 1. To such regard, the material web N of the support S (in particular of the stack 3 of the bale 2) from which the material is picked up can be aligned (namely in line) or misaligned (even if parallel) with the advancement path PA in the machine 1.

[0087] Similar to what described in the foregoing also in this case, according to a possible variant, the deviation element 13 is present.

[0088] Advantageously, but not limitedly, for any one of the embodiments previously described, the arm 8 carrying the feeding head 7 can be fixed or movable. In the case where the arm 8 carrying the feeding head 7 is movable, it is configured to move the feeding head 7 between a raised position (illustrated by a solid line in the accompanying Figures 2, 3 and 6-12), in which the feeding of the material web N to the machine 1 normally occurs, and a lowered in particular temporary position (illustrated by a dashed line in the accompanying Figures 2, 6-8 and 11 ), in which the threading of the material web N is carried out at the first feeding of the web N to the machine 1. To such regard, the feeding unit 5 comprises an actuation module 16 provided with an actuation device 17 of the arm 8 configured to rotate it around a rotation axis X5 (arranged horizontal, in particular parallel to the axes X3 of the deflection elements 12) so as to move it between the raised position and the lowered position. In the accompanying figures, which are not limiting, the actuation module 16 is arranged on the stabilizing unit 6 in such a way as to make the machine 1 more compact.

[0089] Advantageously, but not limitedly, the machine 1 comprises an annular guiding element 18 (schematically illustrated in Figures 2, 6-8 and 11) arranged between the feeding head 7 and the bale 2, and is configured to guide the material web N in the upward path towards the feeding head 7. It is understood that the guiding element 18 can have a different shape with respect to the annular one illustrated in Figures 2, 6-8, 11.

[0090] Advantageously, in order to ensure a twist of the material web N without damage (such as for example a plastic deformation, in particular folding, or laceration) of the web N, the ratio between the length of the web N to be stabilized (in particular the length of the web N measured between the two deflection elements 12 arranged directly upstream and downstream of the two stabilizing elements 11 ) and the width of the del web N to be stabilized is comprised between 4 and 12 (preferably between 6 and 10).

[0091] According to a possible embodiment, the machine 1 further comprises the machining unit 14 (previously described). The machining unit 14 comprises, for example, a pair of rollers intended to be passed through by the stabilized material web N (i.e. downstream of the stabilizing module 10) for impressing on the web N longitudinal weakening lines of the web N or for cutting the web N in strips. Such machining unit 14 is known in the field and, therefore, is not described in detail.

[0092] Preferably, the stabilizing unit 6 is arranged upstream of the machining unit 14. In particular, the stabilizing unit 6 is arranged between the feeding unit 5 and the machining unit 14. Preferably, but not necessarily, the machining unit 14 is arranged upstream of the forming unit 15.

[0093] According to a possible embodiment, in proximity to (in particular at) the inlet station SI a countered unwinding element is arranged. The countered unwinding element is preferably, but not necessarily, a countered unwinding roller. In particular, the countering effect is defined by a further preferably idle element (in particular roller).

[0094] According to a further embodiment, the machine 1 comprises (in particular at the feeding head 7) an unwinding element configured to manage (in particular adjust and / or control) the speed and / or the tension of the web N in the temporary twist. The unwinding element is preferably an unwinding roller, in particular a motorized roller, more in particular a countered motorized roller. Preferably, the unwinding element is arranged downstream of the feeding elements 9 of the feeding head 7.

[0095] Advantageously, but not necessarily, the machine 1 comprises one or more detection means, in particular sensors, configured to detect the position of the web N (along a direction that is transverse to its longitudinal extension). In particular, in the embodiments wherein such feeding elements 9 are rollers, the detection means are configured to detect if the web N falls from one of the feeding elements 9, for example due to the drifting of the web N. In particular, such detection means are arranged at the feeding head 7. Preferably, the detection means are arranged at the portions of web N supported between two feeding elements 9.

[0096] According to a possible variant, the machine 1 also comprises one or more of the aforementioned detection means at the elements 11-13, in particular in the embodiments wherein such elements are rollers.

[0097] According to a further aspect of the present invention, a forming method for forming a rod of the tobacco industry is provided. The method described in the following is preferably carried out by the previously described machine 1.

[0098] In the following, the modes with which the machine 1 feeds and stabilizes the material web N, which is subsequently used for forming the rod of material, are described. In particular, as previously mentioned, the stabilized material web N is a filler material or a wrapping material. According to a possible alternative both the filler material web and the wrapping material web are stabilized. According to a possible embodiment, the method mainly (but not exclusively) comprises the steps of:

[0099] feeding by means of the feeding unit 5 a material web N having a longitudinal extension L and having the first orientation;

[0100] stabilizing by means of the stabilizing unit 6 arranged downstream of the feeding unit 5 and comprising at least one stabilizing module 10 configured to perform a temporary twist of the material web N about its longitudinal axis, parallel to the longitudinal extension L in such a way as to stabilize the advancement of the material web N; each stabilizing module 10 comprises at least two stabilizing elements 11 (in particular the elements 11 A and 11 B or 11 C and 11 D) arranged in succession one behind the other along the advancement direction (DA) of the web (N); wherein the stabilizing step comprises the sub-steps of:

[0101] a) performing by means of the first stabilizing element 11 (in particular 11A or 11 C illustrated in the accompanying figures) the first twist of the material web N about its longitudinal axis, parallel to the longitudinal extension L, of the angle a (i.e. a1 or a3), such that the material web N has the longitudinal extension L extending with the second orientation which is transverse, preferably orthogonal, to the first orientation; and

[0102] b) performing by means of the second stabilizing element 11 (in particular 11 B or 11 D illustrated in the accompanying figures) a second twist of the material web N about its longitudinal axis, parallel to the longitudinal extension L, of the angle a (i.e. a2 or a4), such that downstream of the second stabilizing element 11 (in particular 11 B or 11 D illustrated in the accompanying figures) the material web N extends with an orientation that is different from the second orientation;

[0103] forming the rod by means of the forming unit 15 configured to form the rod with the material web N, wherein the material web N is a filler material or a wrapping material.

[0104] Advantageously, but not limitedly, the second twist of the web N is carried out with a direction of rotation which is equal to or opposite the direction of rotation of the first twist. Additionally or alternatively, the second twist of the web N is carried out with an angle a2 having an absolute value equal to or different from the absolute value of the angle a1. Advantageously, the twist is carried out with the angle a (namely the angles a1 and a2, but also the angles a3 and a4 described in the following) is comprised between 60° and 120°, in particular between 80° and 100°, preferably equal to 90°.

[0105] Advantageously, but not limitedly, according to a first variant (carried out for example by the machine 1 illustrated in Figures 2-4), the method comprises the steps of:

[0106] providing the stabilizing unit 6 comprising at least two deflection elements 12 (in particular deflection rollers 12), each provided with a respective, in particular horizontal, axis X3 (in particular rotation axis); and

[0107] providing the stabilizing elements 11 arranged between the at least two deflection elements 12; preferably each axis X3 of the deflection elements 12 is transverse, in particular orthogonal, to the axis X2 of the stabilizing elements 11; and the rotation axes of the two stabilizing elements 11 are arranged horizontally; and

[0108] in particular, aligning a first axial position, with respect to the axis X3 of the first deflection element 12, with respect to a second axial position, with respect to the axis X3 of the second deflection element 12, at the second deflection element 12.

[0109] According to a possible non-limiting variant, carried out for example by the machine 1 illustrated in Figure 5 (which is a variant of Figures 2-4), the method comprises the steps of:

[0110] providing a deviation element 13 of the material web N, in particular a deviation roller provided with the axis X4 (in particular rotation axis around which it is configured to rotate); the deviation element 13 is interposed between the two stabilizing elements 11 and is configured to lengthen the path of the web N between the two stabilizing elements 11; and

[0111] deviating the path of the web N by means of the deviation element 13, lengthening the path of the web N between the two stabilizing elements 11. Advantageously, but not limitedly, according to a second variant carried out for example by the machine 1 illustrated for example in Figures 8-10, the method comprises the steps of:

[0112] providing the stabilizing unit 6 comprising at least two deflection elements 12 each provided with a respective, in particular horizontal, axis X3 and the stabilizing elements 11 are arranged between the two deflection elements 12; and each axis X3 of the deflection elements 12 is transverse, in particular orthogonal, to the axis X2 of the stabilizing elements 11; and the axes X2 of the two stabilizing elements 11 are arranged vertically; and

[0113] misaligning (by an amount substantially equal to the width of the web N) a first axial position, with respect to the axis X3’ of the first deflection element 12, with respect to a second axial position, with respect to the axis X3” of the second deflection element 12, at the second deflection element 12.

[0114] Advantageously, but not limitedly, according to a third variant carried out for example by the machine 1 illustrated for example in Figure 6, the method comprises the steps of:

[0115] providing the stabilizing unit 6 comprising at least two deflection elements 12 both arranged at the feeding head 7; preferably the two deflection elements 12 have a respective axis X3 which is horizontal and transverse to the axis X2 of the stabilizing elements 11; the stabilizing elements 11 are interposed between the two deflection elements 12 and are arranged outside the feeding head 7; and misaligning (by an amount substantially equal to the width of the web N) a first axial position, with respect to the axis X3 of the first deflection element 12, with respect to a second axial position of the material web N at the feeding head 7.

[0116] Advantageously, but not limitedly, according to a fourth variant carried out for example by the machine 1 illustrated in Figures 11 and 12, the method comprises the steps of:

[0117] - providing the stabilizing unit 6 comprising at least two stabilizing modules 10; preferably (but not limitedly) the stabilizing module 10A is made according to the embodiment illustrated in Figure 6 and the stabilizing module 10B is made according to the embodiment of Figures 2-4 or 5; - performing by means of the stabilizing module 10A two first temporary twists; one of the angle a1 and the other of the angle a2;

[0118] - performing by means of the stabilizing module 10B two second temporary twists; one of the angle a3 and the other of the angle a4;

[0119] - wherein the absolute values of at least two of: the angle a1, the angle a2, the angle a3 and the angle a4 are equal to or different from each other; and / or the direction of rotation of the temporary twists of at least two of: the angles a1, a2, a3 and a4 are equal to or opposite each other.

[0120] Advantageously, but not limitedly, according to a fifth variant carried out for example by the machine 1 illustrated for example in Figures 2, 6-8 and 11, the method comprises the steps of:

[0121] receiving the material web N at the feeding head 7 with an orientation that is different from the first orientation; and

[0122] feeding the material web N arranging the support S with respect to the feeding head 7 in such a way as to make a preliminary twist of the material web N about its longitudinal axis, parallel to the longitudinal extension L, by the angle β.

[0123] Advantageously, but not limitedly, the feeding step comprises a sub-step of picking up the material web N from the previously described flat support S.

[0124] Advantageously, but not limitedly, if the arm 8 is movable, the step of feeding the material web N comprises a sub-step of moving, in particular by means of the actuation module 16, the feeding head 7 between: a raised position (illustrated by a solid line in the accompanying Figures 2, 3 and 6-12), in which the feeding of the material web N to the machine 1 normally occurs, and a lowered in particular temporary position (illustrated by a dashed line in the accompanying Figures 2, 6-8 and 11 ), in which the threading of the material web N is carried out at the first feeding of the web N to the machine 1.

[0125] Advantageously, but not limitedly, the step of feeding the web N comprises a substep (which preferably occurs at least partially simultaneously with the feeding step) of managing (in particular adjusting and / or controlling) the speed and / or the tension of the web N in the temporary twist by means of an unwinding element arranged in particular at the feeding head 7. In particular, in the step of managing the speed and / or the tension of the web N, the unwinding element acts on the web downstream of the feeding elements 9.

[0126] Advantageously, but not necessarily, the method comprises at least a step of detecting the position (along a direction that is transverse to its longitudinal extension) of the web N by means of one or more detection means, in particular sensors, which are arranged in particular at the feeding head 7. In particular, in the embodiments wherein such feeding elements 9 are rollers, the detection means are configured to detect if the web N falls from one of the feeding elements 9, for example due to the drifting of the web N. Preferably, the step of detecting the position occurs at least partially at the same time of the step of feeding the web N.

[0127] Advantageously, but not necessarily, the method can comprise further steps of detecting the position of the web by means of the aforementioned detection means which can be arranged at the elements 11-13, in particular in the embodiments wherein such elements are rollers. In such case, the step of detecting the position occurs at least partially at the same time of the respective steps carried out by the elements 11-13.

[0128] The machine 1 and the method described so far have a plurality of advantages. Firstly, the temporary twist is applicable to the material web N picked up from the reel or from the flat support (i.e. from the bale 2).

[0129] Secondly, by performing the at least one temporary twist it is possible to induce in the branch of the material web N upstream and downstream of the stabilizing elements 11 a tension of equal magnitude, but with opposite direction, in such a way as to prevent an axial displacement (i.e. a lateral displacement) of the web N.

[0130] Therefore, the machine 1 has a material web N that is fed in the absence of lateral sways.

[0131] Thirdly, being the at least one temporary twist carried out in such a way as to not permanently deform the web N or as to not tear it, the web N subjected to the stabilization as previously described does not show on it any trace of the twist carried out.

[0132] The rod obtained through the web N has a greater quality, as the axial position of the web N in the machine 1 is ensured and maintained. Therefore, it is possible to reduce the wastes.

[0133] The machine 1 is produced in a simple and cost-effective manner since, with respect to a similar and known machine, it requires modifications that are easily implementable.

[0134] Furthermore, the stabilizing unit 6 is easily implementable also in preexisting machines 1, without requiring great adaptation interventions, but by simply adding the further stabilizing unit 6.

[0135] LIST OF THE REFERENCE NUMERALS OF THE FIGURES

[0136] 1 machine

[0137] 2 bale

[0138] 3 stack

[0139] 4 folding

[0140] 5 feeding unit

[0141] 6 stabilizing unit

[0142] 7 feeding head

[0143] 8 arm

[0144] 9 feeding element

[0145] 10 stabilizing module

[0146] 11 stabilizing element

[0147] 12 deflection element

[0148] 13 deviation element

[0149] 14 machining unit

[0150] 15 forming unit

[0151] 16 actuation module

[0152] 17 actuation device

[0153] 18 guiding element

[0154] D1 distance

[0155] D2 distance D3 distance

[0156] D4 distance

[0157] D5 distance

[0158] DP folding directions

[0159] DA advancement direction N material web

[0160] L longitudinal extension S support

[0161] SI inlet station

[0162] Sil outlet station

[0163] PA advancement path X1 rotation axis

[0164] X2 axis

[0165] X3 axis

[0166] X3’ axis

[0167] X3” axis

[0168] X3”’axis

[0169] X4 axis

[0170] X5 axis

[0171] a angle

[0172] a1 angle

[0173] a2 angle

[0174] a3 angle a4 angle [3 angle

Claims

C L A I M S1. A machine (1) for forming a rod of the tobacco industry, wherein the machine (1) comprises:a feeding unit (5) configured to feed a material web (N) having a longitudinal extension (L) and having a first orientation;a stabilizing unit (6) arranged downstream of the feeding unit (5) and comprising at least one stabilizing module (10) configured to perform a temporary twist of the material web (N) about its longitudinal axis, parallel to the longitudinal extension (L) in such a way as to stabilize the advancement of the material web (N); each stabilizing module (10) comprises at least two stabilizing elements (11; 11 A, 11 B; 11 C, 11 D) arranged in succession one behind the other along the advancement direction (DA) of the material web (N); wherein:- the first stabilizing element (11; 11 A; 11 C) is designed and configured to cause a first twist of the material web (N) about its longitudinal axis by a first angle (a, a1), such that the material web (N) has a longitudinal extension (L) extending with a second orientation that is transverse, preferably orthogonal, to the first orientation; and- the second stabilizing element (11; 11 B; 11 D) is designed and configured to cause a second twist of the material web (N) about its longitudinal axis by a second angle (a; a2) such that the material web (N) has a longitudinal extension (L) extending with an orientation that is different from the second orientation; anda forming unit (15) configured to form the rod with the material web (N), wherein the material web (N) is a filler material or a wrapping material.

2. The machine (1) according to claim 1, wherein the first angle (a; a1; a3) and the second angle (a; a2; a4) are each comprised between 60° and 120°, in particular between 80° and 100°, preferably equal to 90°.

3. The machine (1) according to claim 1 or 2, wherein the absolute value of the first angle (a1) and the absolute value of the second angle (a2) are equal to or different from each other; and / or wherein the direction of rotation of the first twist and the direction of rotation of the second twist are equal to or different from each other.

4. The machine (1) according to any preceding claim, wherein:the feeding unit (5) comprises a feeding head (7) configured to pick up the material web (N); the feeding head (7) is carried by an arm (8), which is movable to move the feeding head (7) between a raised position in which the feeding of the material web (N) to the machine (1) normally occurs, and a lowered in particular temporary position, in which the threading of the material web (N) is carried out at the first feeding of the material web (N) to the machine (1 ).

5. The machine (1) according to any preceding claim, wherein the feeding unit (5) is configured to pick up the material web (N) from at least one bale (2) comprising the material web (N) arranged either neatly or haphazardly.

6. The machine (1 ) according to claim 5 when dependent on claim 4, wherein the bale (2) comprises the material web (N) arranged neatly in at least one stack (3) of material web (N); the material web (N) of each stack (3) comprises a plurality of folds extending transverse, in particular orthogonal, to the longitudinal extension (L) of the material web (N); wherein preferably each fold is made in opposite and alternating folding directions (DP) so that two successive layers obtained by folding the material web (N) are parallel to each other; wherein at the feeding head (7) the material web (N) has the first orientation.

7. The machine (1) according to any preceding claim, wherein:the stabilizing unit (6) comprises at least two deflection elements (12), preferably deflection rollers each provided with a respective, in particular horizontal, first axis (X3; X3’, X3”); and the stabilizing elements (11; 11 A, 11B; 11C, 11 D) are arranged between the at least two deflection elements (12).

8. The machine (1) according to any preceding claim, wherein:the stabilizing elements (11; 11 A, 11B; 11C, 11 D) are stabilizing rollers each provided with a respective second axis (X2), in particular rotation axis (X2) around which they are configured to rotate.

9. The machine (1) according to claim 8, wherein:the two stabilizing elements (11; 11 A, 11 B; 11 C, 11 D) are arranged in proximity to each other and the first axes (X2) of the two stabilizing elements (11; 11A, 11 B; 11 C, 11 D) lie on two vertical planes which are parallel to each other.

10. The machine (1) according to any preceding claim, wherein:the stabilizing unit (6) comprises a deviation element (13) of the material web (N), in particular a deviation roller provided with a third axis (X4) which is in particular a rotation axis around which it is configured to rotate; the deviation element (13) is interposed between the two stabilizing elements (11; 11 A, 11 B; 11 C, 11 D) and is configured to lengthen the path of the material web (N) between the two stabilizing elements (11; 11 A, 11 B; 11 C, 11 D);preferably the third axis (X4) of the deviation element (13) is arranged on a third vertical plane which is parallel to and spaced apart by a third distance (D3) from the vertical planes in which the first two axes (X2) of the stabilizing elements (11; 11 A, 11 B; 11 C, 11 D) lie.

11. The machine (1) according to any one of claims 7 to 10, wherein:the second axes (X3; X3’, X3”) of the deflection elements (12) lie on two horizontal planes which are parallel and spaced apart by a fourth distance (D4); andthe first axes (X2) of the two stabilizing elements (11; 11 A, 11 B; 11C, 11 D) lie coplanar on the same fourth vertical plane and are spaced apart from each other by a fifth distance (D5).

12. The machine (1) according to claim 4 or any one of claims 5 to 11 when the latter depend on at least claim 4, wherein the stabilizing elements (11; 11 A, 11 B; 11 C, 11 D) are arranged integral with the movable arm (8) of the feeding unit (5).

13. The machine (1) according to any one of the preceding claims, wherein: the stabilizing unit (6) comprises at least two stabilizing modules (10); wherein the first stabilizing module (10; 10A) performs two first temporary twists; one of a first angle (a; a1 ) and the other of a second angle (a; a2); andthe second stabilizing module (10; 10B) performs two second temporary twists; one of a third angle (a; a3) and the other of a fourth angle (a; a4).

14. The machine (1) according to claim 4 or to any one of claims 5 to 13 when the latter depend on at least claim 4, wherein:the feeding head (7) is configured to receive the material web (N) with anorientation that is different from the first orientation; wherein the support (S) is arranged with respect to the feeding head (7) in such a way as to make a preliminary twist of the material web (N) about its longitudinal axis, parallel to the longitudinal extension (L), by a third angle ([3).

15. The machine (1) according to any one of the preceding claims, wherein, in particular at the feeding head (7), the machine (1) comprises an unwinding element configured to manage, in particular adjust and / or control, the speed and / or the tension of the material web (N); the unwinding element is preferably an unwinding roller, in particular is a motorized roller, more in particular is a countered motorized roller.

16. A method for forming a rod of the tobacco industry, wherein the method comprises the steps of:feeding by means of the feeding unit (5) a material web (N) having a longitudinal extension (L) and having a first orientation;stabilizing by means of a stabilizing unit (6) arranged downstream of the feeding unit (5) and comprising at least one stabilizing module (10) configured to perform a temporary twist of the material web (N) about its longitudinal axis, parallel to the longitudinal extension (L) in such a way as to stabilize the advancement of the material web (N); each stabilizing module (10) comprises at least two stabilizing elements (11; 11 A, 11 B; 11 C, 11 D) arranged in succession one behind the other along the advancement direction (DA) of the material web (N); wherein the stabilizing step comprises the sub-steps of:- performing by means of the first stabilizing element (11; 11 A; 11 C) a first twist of the material web (N) about a longitudinal axis thereof, parallel to the longitudinal extension (L), by a first angle (a; a1), such that the material web (N) has the longitudinal extension (L) extending with a second orientation that is transverse, preferably orthogonal, to the first orientation; and- performing by means of the second stabilizing element (11; 11 B; 11 D) a second twist of the material web (N) about its longitudinal axis, parallel to the longitudinal extension (L), by a second angle (a; a2) such that the material web (N) has a longitudinal extension (L) extending with an orientation that is different from the second orientation; andforming the rod by means of a forming unit (15) configured to form the rod withthe material web (N), wherein the material web (N) is a filler material or a wrapping material.

17. The method according to claim 16, wherein the step of performing the second twist of the material web (N) occurs with:an absolute value of the second angle (a2) that is equal to or different from the absolute value of the first angle (a1) with which the step of performing the first twist is carried out; and / orthe direction of rotation with which the step of performing the first twist is carried out and the direction of rotation with which the step of performing the second twist is carried out are equal to or different from each other.

18. The method according to claim 16 or 17, wherein the feeding unit (5) comprises a feeding head (7) configured to pick up the material web (N); the feeding head (7) is carried by a movable arm (8) to move the feeding head (7); and wherein the step of feeding the material web (N) comprises a sub-step of moving the feeding head (7) between:a) a raised position, in which the feeding of the material web (N) to the machine (1) normally occurs, andb) a lowered in particular temporary position, in which the threading of the material web (N) is carried out at the first feeding of the material web (N) to the machine (1).

19. The method according to claim 18 or to any one of claims 16 and 17, wherein the step of feeding the material web (N) comprises a sub-step of managing, in particular adjusting and / or controlling, the speed and / or the tension of the material web (N) by means of an unwinding element arranged in particular at the feeding head (7); the managing step preferably occurs at least partially simultaneously with the feeding step.

20. The method according to any one of claims 16 to 19, comprising the step of: providing the stabilizing unit (6) comprising at least two stabilizing modules (10); performing by means of the first stabilizing module (10; 10A) two first temporary twists; one of a first angle (a; a1 ) and the other of a second angle (a; a2); andperforming by means of the second stabilizing module (10; 10B) two second temporary twists; one of a third angle (a; a3) and the other of a fourth angle (a; a4);wherein the absolute values of at least two of: the first angle (a; a1 ), the second angle (a; a2), the third angle (a; a3) and the fourth angle (a; a4) are equal to or different from each other; and / or the direction of rotation of the temporary twists of at least two of: the first angle (a; a1 ), the second angle (a; a2), the third angle (a; a3) and the fourth angle (a; a4) are equal to or opposite each other.

Images