A unit and method for laminating a continuous plantbased layer.

Abstract

A unit (1) for laminating a continuous plant-based layer of the smoking articles industry, comprising a support frame (2), and at least one pair of mutually opposite laminating rollers (10, 20) rotatably mounted on the support frame (2). Each roller (10, 20) is rotatable about a respective 5 rotation axis (X, Y). The unit (1) comprises an adjustment apparatus (30) for the upper roller (10), acting on the ends (11, 12) of the upper roller (10) and configured to vary the orientation of the rotation axis (X) of the upper roller (10) with respect to the rotation axis (Y) of the lower roller (20) by moving said ends (11, 12) of the upper roller (10) at least in an adjustment 10 plane parallel to a movement direction (6) of the continuous layer, so as to change a width of the passage space (5).

Description

[0001] DESCRIPTION

[0002] A UNIT AND METHOD FOR LAMINATING A CONTINUOUS PLANTBASED LAYER

[0003] Technical field

[0004] The present invention relates to a unit and a method for laminating a continuous plant-based layer in the industry of smoking articles.

[0005] Background art

[0006] In the relevant field of the present invention, laminating a continuous plantbased layer is known, where the expression "plant-based" is intended to mean a material (tobacco or non-tobacco) obtained by grinding or other similar procedure to change the grain size thereof in order to promote subsequent mixing treatments. In particular, the continuous layer is intended to be a semi-finished product obtained from the mixing and processing of at least one dry plant-based component made of fibers and / or powder, such as, for example, tobacco or non-tobacco (cellulose or cellulose derivatives, rapeseed, hemp, straw or other varieties, hemp, aromatic leaves or other) with a moist component, such as, for example, water and one or more additives, according to the generality of the invention.

[0007] Laminating is an essential process for producing continuous layers. This process is performed with a unit comprising at least one laminating stage, which is provided with a pair of opposite laminating rollers, mutually defining a passage space through which the material is passed so as to be worked in the form of a continuous layer having a calibrated (laminated) thickness. The at least one laminating stage may be of the vertical or horizontal type.

[0008] In the field relating to the present invention, the need is strongly felt to ensure uniformity in the thickness of the continuous layer. However, one known problem in the lamination process concerns the bending suffered by the rollers due to the pressure exerted by the mixture on the same rollers. In other words, the rollers tend not to maintain perfect linearity, but they tend to bend slightly. This bending of the rollers leads to a change in the thickness of the continuous layer, resulting in a greater thickness in the middle portion and a smaller thickness in the end portions. This bending is thus more evident in the middle portion of the rollers.

[0009] This problem is particularly felt and exacerbated in the case of a horizontal laminating stage, comprising an upper roller and a lower roller. Indeed, while the upper roller benefits from the weight thereof, which at least partially contrasts the bending generated by the mixture, the lower roller undergoes a combined effect of the weight force thereof and the force exerted by the mixture, resulting in significant bending. This sum of forces on the lower roller results in a marked bending, compromising the uniformity of the thickness of the continuous layer.

[0010] In this context, the technical task of the present invention is thus to provide a unit and a method for laminating a continuous plant-based layer, in particular of the smoking articles industry, which overcome the drawbacks of the prior art.

[0011] Disclosure of the invention

[0012] It is therefore the object of the present invention to provide a unit and a method for laminating a continuous plant-based layer, in particular of the smoking articles industry, capable of obtaining a finished product of satisfactory quality, with particular reference to the thickness and which are efficient and optimized.

[0013] The specified technical task and the specified object are substantially achieved by a unit for laminating a continuous plant-based layer, in particular of the smoking articles industry, according to the present invention. The specified technical task and the specified object are also achieved by a method for laminating a continuous plant-based layer, in particular of the smoking articles industry, according to the present invention, which is performed by means of the aforesaid unit.

[0014] In particular, the unit comprises a support frame having a first upright and a second upright and at least one pair of opposite laminating rollers, rotatably mounted on the support frame. Each pair of rollers comprises an upper roller and a lower roller, mutually defining a passage space, configured to laminate a material obtaining a continuous layer.

[0015] Each roller is rotatable about a respective rotation axis and has a first end rotatably supported on the first upright and a second end, opposite the first end, rotatably supported on the second upright.

[0016] The unit comprises an adjustment apparatus for the upper roller, acting on the ends of the upper roller and configured to vary the orientation of the rotation axis of the upper roller with respect to the rotation axis of the lower roller, by moving the ends of the upper roller at least in an adjustment plane parallel to a movement direction of the continuous layer, so as to change a width of the passage space. In other words, the unit is provided with an adjustment system for adjusting the upper roller, which acts on the ends of the upper roller, and which is configured to change the orientation of the rotation axis thereof with respect to the rotation axis of the lower roller. This system allows moving the ends of the upper roller at least within an adjustment plane parallel to the feeding direction of the continuous layer, so as to vary the configuration of the passage space between the rollers, canceling the amplitude differences along the transverse development of the passage space.

[0017] At a functional level, a step is preferably provided in which at least one effective thickness value of the continuous layer exiting the aforesaid passage space and / or of the width of the passage space is detected in at least one measurement point and a subsequent step in which the width of the space is adjusted as a function of the at least one effective value detected. Therefore, this adjustment is made by varying the orientation of the rotation axis of the upper roller with respect to the rotation axis of the lower roller by moving the ends of the upper roller at least within the aforesaid adjustment plane.

[0018] The Applicant has observed that the aforesaid laminating system, which implements an adjustment apparatus for adjusting the upper roller according to the aforesaid technical specifications, allows obtaining an efficient and reliable process so as to achieve a qualitatively satisfactory product.

[0019] Firstly, the adjustment apparatus allows equalizing the width of the passage space along the transverse development of the passage space, so as to obtain a continuous plant-based layer with a uniform thickness along the entire width thereof, overcoming the thickness variation problems caused by the bending of the rollers. A qualitatively superior final product is obtained by minimizing the thickness differences along the width of the continuous layer.

[0020] Secondly, the adjustment apparatus improves the efficiency of the laminating process. By virtue of the dynamic adjustment of the passage space, it is possible to rapidly and accurately adapt the laminating process in response to changes in the properties of the mixture or in the operating conditions. This results in increased productivity and reduced processing waste, with significant financial benefits for the smoking articles industry.

[0021] In summary, the use of the adjustment apparatus for the upper roller according to the aforesaid technical features ensures a high-quality final product, greater process efficiency and an optimized, versatile structure.

[0022] The unit and method according to the present invention may further provide one or more of the technical aspects, which will be outlined in the following present description.

[0023] According to an aspect, the adjustment apparatus for the upper roller is configured to move the end of the upper roller in opposite directions along the adjustment plane. In other words, taking into account the movement direction of the continuous layer, one end of the upper roller will be advanced with respect to the corresponding end of the lower roller, while the other end of the upper roller will be retracted with respect to the corresponding end of the lower roller. With this type of adjustment, the axes of the upper roller and the lower roller intersect, substantially defining a letter “X” configuration when seen from above. This opposite movement of the ends of the upper roller allows a more accurate and uniform adjustment of the passage space, improving control over the thickness of the continuous layer.

[0024] According to an aspect, the movement apparatus is configured to move the ends independently of each other. In other words, each end of the upper roller may be adjusted separately with respect to the other, allowing individual control over the position of each end at least along the aforesaid adjustment plane. This technical feature offers an extremely accurate adjustment of the passage space between the rollers, since each end of the upper roller may be moved independently, to adapt to the specific laminating requirements. This allows compensating for localized nonuniformities or changes in the configuration of the rollers, ensuring that the thickness of the continuous layer remains constant and uniform.

[0025] The adjustment apparatus for the upper roller may also be configured to allow the displacement of the ends of the upper roller, also transversely to the feeding direction of the continuous layer, in particular perpendicularly to the plane of tangency between the two rollers, allowing the ends of the upper roller to be brought closer to, or distanced from the ends of the lower roller, so as to further adjust the width of the passage space. In other words, the system may determine a combined three-dimensional movement of the upper roller, allowing both a movement parallel to the feeding direction of the continuous layer to equalize the width of the space along the transverse development, and a perpendicular movement to move the ends of the upper roller closer to, or further away from those of the lower roller, ensuring a more precise control over the passage space.

[0026] According to a particularly advantageous embodiment, each of the ends of the upper roller is mounted on the respective upright by means of an eccentric rotatable support. Each rotatable support is rotatable about a respective rotation axis, eccentric with respect to the axis of the upper roller, so that a rotation of the rotatable support results in a displacement of the end of the axis of the upper roller. In other words, each end of the upper roller is mounted on a respective rotatable support, rotatable about a rotation axis thereof, which is eccentric relative to the axis of the upper roller. When the rotatable support is rotated, the position of the end of the upper roller with respect to the initial position thereof is modified. Advantageously, this solution allows both the stated parallel and perpendicular movements.

[0027] The rotation axis of each rotatable support is preferably fixed with respect to the upright.

[0028] The rotation axes of the rotatable supports are preferably coincident. In other words, the rotatable supports substantially rotate about the same rotation axis.

[0029] Each rotatable support preferably accommodates a respective rolling bearing, preferably orientable, which is mounted, in turn, to the respective end of the upper roller.

[0030] This configuration allows the ends of the upper roller to be movable along a respective curved, preferably circular trajectory, about the rotation axis of the respective circular support, in opposite directions to each other.

[0031] According to an example, during the adjustment step for the upper roller, the two ends of the upper roller are moved along the respective circular trajectory, in mutually opposite directions and downwards. In other words, the rotation of each rotatable support results in a displacement of the respective end of the axis of the upper roller preferably downwards, so that the upper roller is moved closer to the lower roller.

[0032] According to an aspect, the unit may comprise at least one measuring device, mounted on the support frame and configured to measure an effective value of the width of the passage space and / or of the thickness of the continuous layer exiting the passage space in at least one point along the transverse development of the space and / or of the continuous belt, respectively.

[0033] According to a particularly advantageous embodiment, the measuring device is configured to measure the effective value of the width of the passage space and / or of the thickness of the continuous layer exiting the passage space in at least three points: at least a first measuring point positioned at a substantially central position of the passage space and / or of the continuous layer and at least two measuring points, positioned in a decentered position, opposite the first measuring point, in particular close to opposite ends of the passage space or the continuous layer.

[0034] Advantageously, configuring the measuring device to detect the effective value of the width of the passage space and / or of the thickness of the continuous layer in three separate points (one of which central and two close to opposite ends) offers significant advantages for controlling the quality of the laminating process. By measuring the width of the passage space and the thickness of the continuous layer at a middle point and in two points at the ends, it is possible to obtain an accurate representation of the effective deformation of the rollers during the operation. This arrangement allows identifying any changes in the thickness of the continuous layer due to the bending of the rollers, which typically presents itself as a greater thickness in the middle portion with respect to the ends. Consequently, with these measurements, it is possible to detect and correct the thickness differences along the axis of the rollers, thus ensuring a more uniform and accurate lamination. This accurate control contributes to improving the quality of the final product, reducing undesired changes in the thickness of the continuous layer and ensuring greater uniformity and consistency of the laminated material.

[0035] This technical feature is even more advantageous when it is possible to independently adjust the ends of the upper roller. In fact, the ability to independently adjust each end of the upper roller allows locally compensating for the differences detected in the measurements. This combination of accurate measurement and independent adjustment significantly improves the quality and reliability of the laminating process, reducing any changes in thickness to a minimum while improving the consistency of the final product.

[0036] According to an aspect, the adjustment apparatus may comprise, for each rotatable support, at least one actuator configured to preferably continuously perform a calibrated rotation of the rotatable support about the respective rotation axis so as to change the position of the corresponding end of the upper roller. Each actuator is preferably mounted on the respective upright.

[0037] Advantageously, independently of the type of actuator, at least one of the upright and the respective rotatable support may comprise a graduated scale, for providing a visual indication of the angular position taken by the rotatable support. This measuring instrument allows accurately displaying the rotation angle of the rotatable support, thus facilitating the control and exact setting of the position of the end of the upper roller. In fact, the graduated scale provides an immediate guide for performing accurate and repeatable adjustments, improving the precision of the adjustment process and ensuring that the passage space between the rollers can be adjusted in a consistent and reliable manner.

[0038] According to an aspect, the adjustment of the width of the passage space may be performed manually or in a completely automated manner.

[0039] According to a first embodiment, the actuators are of the manual type. For example, each actuator may be a screw / nut system configured to continuously perform the aforesaid calibrated rotation of the rotatable support. In particular, according to this example, the actuator is connected to the rotatable support in an eccentric position with respect to the rotation axis of the same support. This allows manually adjusting the position of the end of the upper roller end with precision, facilitating the setting of the width of the passage space and thus the desired thickness of the continuous layer.

[0040] According to a second embodiment, the actuators are of the automatic type. For example, each actuator may be an electric actuator configured to continuously perform the aforesaid calibrated rotation of the rotatable support. However, according to this example, the actuator is activatable and controllable by the operator after detecting the at least one effective thickness value of the continuous layer exiting the passage space and / or of the same passage space width.

[0041] According to a third embodiment, the adjustment of the passage space is completely automated. According to this example, the actuators are automatic actuators, preferably electric actuators. The unit comprises a control unit, connected to the automatic actuator and to the at least one measuring device, configured to control the actuators as a function of the at least one effective measured value. Advantageously, the ability to automatically adjust the actuator in response to real-time measurements allows precise and automated control of the laminating process. In fact, the adoption of automated adjustment apparatus significantly improves operational efficiency and product quality.

[0042] According to an aspect, independently of the type of actuators used, the adjustment apparatus further comprises, for each rotatable support, a fastening system configured to lock the rotatable support in a determined angular configuration.

[0043] This fastening system may be of the manual or automatic type.

[0044] According to an example in which the fastening system is of the manual type, at least one slot is provided, formed in the rotatable support and at least one tightening member, inserted into the slot and tightenable on the respective upright.

[0045] Advantageously, independently of the type of fastening, the integration of a fastening system in the adjustment apparatus allows locking the respective rotatable support in a given angular configuration: once the optimal configuration of the passage space has been reached to obtain the desired thickness of the continuous layer, the fastening system ensures that this configuration is stably maintained during the operation. This eliminates the risk of undesired movements or changes in the adjustment caused by vibrations or other operational forces, ensuring constant and uniform quality of the finished product. In summary, the fastening system improves the precision and stability of the adjustment, contributing to a more reliable and repeatable laminating process.

[0046] According to an aspect, the upper roller may be a motorized roller, associated with a respective engine mounted in a cantilevered manner at a respective end of the upper roller. In this embodiment, a support arm is preferably provided for the end associated with the engine, mounted on the respective upright and connected to the end of the upper roller so as to at least partially transfer, onto the support frame, the weight of the engine. Advantageously, the support arm alleviates the direct load, which the weight of the engine applies onto the adjustment apparatus, by transferring it directly onto the same upright. This technical feature prevents the weight and stresses generated by the engine from directly influencing the adjustment apparatus, thus preserving the accuracy and stability of the same adjustments.

[0047] According to a particularly advantageous embodiment, the support arm is adjustably mounted on the upright at least in the aforesaid adjustment plane so as to adapt the position and / or orientation of the support arm to the change in position of the respective end of the upper roller.

[0048] For example, the support arm may be connected to the upright by means of an eccentric connection. This eccentric connection has constructional and structural features similar to the previously described rotatable support, used to mount the ends of the upper roller to the upright of the support frame. This eccentric connection may further comprise a respective actuator configured to change the configuration of the eccentric connection and therefore of the support arm.

[0049] Advantageously, the support arm adjustably mounted on the upright dynamically adapts to changes in position and orientation of the end of the upper roller to which it is connected. This system allows maintaining a constant and well-balanced support for the motorized roller, even when the adjustment apparatus changes the position thereof. The adjustability of the support arm, made with an eccentric connection, allows compensating for changes in the alignment of the upper roller and ensuring that the weight of the engine is mostly, if not completely transferred on the upright of the support frame. This dynamic adaptation prevents the risk of negatively influencing the precision of the adjustment and ensures a uniform and reliable lamination, thus improving the overall performance and duration of the system.

[0050] According to an aspect, the unit may comprise a scraper, mounted on the support frame and associated with the upper roller and configured to create a separation from the surface of the upper roller of the continuous layer exiting the passage space.

[0051] According to an aspect, the position of the scraper may be adjusted so as to adapt to the different configurations taken by the upper roller. For example, the unit may comprise an auxiliary movement apparatus of the scraper, interposed between the support frame and the scraper and configured to vary an orientation of the scraper at least in the plane parallel to the movement direction of the continuous layer so as to adapt the orientation of the scraper to the orientation of the rotation axis of the upper roller.

[0052] The scraper is preferably connected to the upright by means of an eccentric connection. This eccentric connection has constructional and structural features similar to the eccentric rotatable support used to mount the ends of the upper roller to the upright of the support frame. This eccentric connection may further have a respective actuator configured to change the configuration of the eccentric connection and thus of the scraper.

[0053] According to a particularly advantageous embodiment, the scraper has a first connection end, rotatably constrained to the first upright of the support frame, and a second connection end, opposite the first connection end, and rotatably constrained to the second upright of the support frame: the auxiliary movement apparatus of the scraper is configured to move the two ends independently of each other, using a method entirely analogous to that already explained for the adjustment apparatus of the upper roller. In other words, the auxiliary movement apparatus comprises a first auxiliary rotatable support and a first actuator associated with the first connection end of the scraper, interposed between the support frame and this connection end. The auxiliary movement apparatus comprises a second auxiliary rotatable support and a second actuator associated with the second connection end of the scraper, interposed between the support frame and this connection end.

[0054] Advantageously, the aforesaid technical features ensure a fine and accurate adjustment of the contact angle between the scraper and the surface of the upper roller. This adaptation improves the effectiveness of the scraper for removing the continuous layer, it reduces the risk of damage to the material and optimizes the quality of the finished product.

[0055] According to an aspect, the adjustment of the width of the passage space is performed by keeping the lower roller in a predetermined position.

[0056] This predetermined position may be substantially secured or adjusted by means of a movement apparatus for the lower roller. According to this second example, the unit comprises a movement apparatus for the lower roller configured to vary the width of the passage space so as to change the thickness of the continuous layer exiting the pair of rollers, in particular by moving the lower roller towards and away from the upper roller. Structurally, the movement apparatus of the lower roller may comprise a first actuator, connected to the first end of the lower roller and configured to move this first end of the lower roller towards / away from the first end of the upper roller, and a second actuator, connected to the second end of the lower roller and configured to move this second end of the lower roller towards / away from the second end of the upper roller. The first actuator and the second actuator are preferably operable independently of each other.

[0057] At a functional level, a preliminary step may be provided for moving the lower roller by means of the respective movement apparatus of the lower roller so that the lower roller takes the aforesaid predetermined position. Subsequently, once the lower roller has taken the aforesaid predetermined position, based on the measurements made, the position of the upper roller with respect to the lower roller may be changed by means of the adjustment apparatus of the upper roller. In this adjustment step, the lower roller is kept substantially stationary in the predetermined position. However, a further step may be provided for moving the lower roller towards / away from the upper roller, following the adjustment of the upper roller, so as to change the thickness of the continuous layer exiting the passage space.

[0058] Advantageously, the use of a movement apparatus for the lower roller, configured to vary the width of the passage space, allows the precise and dynamic adjustment of the thickness of the continuous layer exiting the pair of rollers. The ability to move the lower roller both towards and away from the upper roller allows a fine and accurate modulation of the thickness of the continuous layer, effectively responding to changes in material and to the required production specifications.

[0059] Further features and advantages of the present invention will become more apparent from the indicative, and therefore non-limiting description of an embodiment of a unit for laminating a plant-based continuous layer, in particular of the smoking articles industry, according to the invention.

[0060] Brief description of drawings

[0061] This description will be set out hereinafter with reference to the accompanying drawings provided purely for indicative and therefore nonlimiting purposes, which show:

[0062] - figure 1 shows a first perspective view of a preferred exemplary, and therefore non-limiting embodiment of a unit for laminating a plant-based continuous layer, in particular of the smoking articles industry, according to the present invention;

[0063] - figure 2 shows a second perspective view of the embodiment of the unit in figure 1 ;

[0064] - figures 3A and 3B show diagrammatic side views of two respective operating configurations of a detail of the unit;

[0065] - figures 4A and 4B show top diagrammatic views of the two operating configurations shown in figures 3A and 3B;

[0066] - figure 5 shows a sectional view of a detail of the embodiment of the unit in figure 1 ;

[0067] - figures 6A and 6B show diagrammatic views of two respective operating configurations of the embodiment of the unit in figure 1 ;

[0068] - figure 7 shows a first side view of the embodiment of the unit in figure 1 ;

[0069] - figure 8 shows a second side view of the embodiment of the unit in figure 1 ;

[0070] With reference to the appended figures, reference numeral 1 denotes a preferred embodiment of a unit for laminating a continuous plant-based layer, in particular for the industry of smoking articles, according to the present invention. The method for laminating a continuous plant-based layer, in particular of the smoking articles industry, will be described with reference to the aforesaid embodiment of unit 1 , which is configured to implement the aforesaid method.

[0071] Detailed description of preferred embodiments of the invention

[0072] The continuous layer according to the present invention is a layer based on material of plant origin. In the present description, the expression "plant origin" is intended to mean a plant-based material (tobacco or nontobacco) processed by grinding or another similar procedure to change the grain size thereof in order to promote subsequent mixture treatments. In particular, it is intended to mean that the continuous layer is a semi- finished product obtained from the mixture and the processing of at least one dry plant component, such as, for example tobacco or non-tobacco (rapeseed, hemp, straw or other varieties, cellulose or cellulose derivatives, hemp, aromatic leaves or other) with a moist component, such as, for example, water and one or more additives, according to the generality of the invention.

[0073] This type of mixture may exhibit poorly elastic behavior, characterized by a predominantly plastic-viscous response. This type of mixture may have high internal cohesion, as well as a high solid phase content, giving a pasty consistency and significant flow resistance. These features determine the need for high laminating pressures and induce concentrated loads and bending stress on the rollers.

[0074] In particular, the material is in the form of a mixture with a pasty consistency (“dough”), having a water content equal to, or less than 65% by weight, preferably less than 60%.

[0075] As visible from figures 1 and 2, the unit 1 comprises a support frame 2 having a first upright 3 and a second upright 4 and a pair of laminating rollers 10, 20, which are opposite each other and rotatably mounted onto the support frame 2.

[0076] In particular, the unit 1 according to the illustrated embodiment comprises a single pair of rollers 10, 20, provided with an upper roller 10 and a lower roller 20, mutually defining a passage space 5 and configured to laminate a material, thus obtaining a continuous layer.

[0077] Each roller 10, 20 is rotatable about a respective rotation axis “X”, “Y” and has a first end 11 , 21 rotatably supported on the first upright 3 and a second end 12, 22, opposite the first end 11 , 21 , rotatably supported on the second upright 4.

[0078] The unit 1 comprises an adjustment apparatus 30 for the upper roller 10, acting on the ends 11 , 12 of the upper roller 10.

[0079] The adjustment apparatus 30 is configured to vary the orientation of the rotation axis “X” of the upper roller 10 with respect to the rotation axis “Y” of the lower roller 20 by moving the ends 11 , 12 of the upper roller 10 at least in an adjustment plane parallel to a movement direction 6 of the continuous layer so as to change a width of the passage space 5.

[0080] At a functional level, there is provided a step of detecting at least one effective thickness value of the continuous layer exiting the passage space 5 and / or of the width of the passage space 5 in at least one measuring point along the transverse development of the passage space 5 and / or of the continuous belt, respectively.

[0081] In the preferred embodiment, the effective thickness values of the continuous layer exiting the passage space 5 and / or of the width of the passage space 5 are detected at three separate measuring points: in particular, a first measuring point, arranged substantially in a central position, and two measuring points arranged in a decentered position and opposite the first measuring point, in particular close to opposite ends of the transverse development of the continuous layer and / or of the laminating rollers 10, 20.

[0082] To this end, the unit 1 comprises a measuring device (not shown in the attached figures), mounted on the support frame 2 and configured to measure the effective value of the width of the passage space 5 and / or of the thickness of the continuous layer exiting the passage space 5 in the aforesaid three measuring points, along the transverse development of the passage space 5 and / or of the continuous layer, respectively.

[0083] As visible from figures 3A, 3B, 4A and 4B, the adjustment apparatus 30 is configured to move the ends 11 , 12 of the upper roller 10 in opposite directions along the adjustment plane and to move these ends 11 , 12 independently of each other.

[0084] In other words, taking into account the movement direction 6 of the continuous layer, one end 12 of the upper roller 10 will be advanced with respect to the corresponding end 22 of the lower roller 20, while the other end 11 of the upper roller 10 will be retracted with respect to the corresponding end 21 of the lower roller 20. With this type of adjustment, the rotation axes “X”, “Y” of the upper roller 10 and the lower roller 20 intersect, substantially forming an “X”. This opposite movement of the ends 11 , 12 of the upper roller 10 enables a more accurate and uniform adjustment of the passage space 5, improving control of the thickness of the continuous layer.

[0085] Figures 3A and 4A show a neutral configuration of the pair of rollers 10, 20 in which no adjustment has been made. In particular, figure 3A shows a diagrammatic side view of the pair of rollers 10, 20 while figure 4A shows a diagrammatic top view of the pair of rollers 10, 20. As clearly visible, in this configuration, the rotation axes “X”, “Y” are parallel, while the respective rollers 10, 20 are mutually aligned. In the view from above of figure 4A, since the rollers 10, 20 are aligned, the lower roller 20 is concealed by the upper roller 10.

[0086] Whereas figures 3B and 4B illustrate a configuration taken by the rollers

[0087] 10, 20 following an adjustment made by the adjustment apparatus 30.

[0088] In this configuration, the end 12 of the upper roller 10 is advanced with respect to the corresponding end 22 of the lower roller 20 with respect to the movement direction 6 of the continuous layer. Furthermore, the end 11 of the upper roller 10 is retracted with respect to the corresponding end 22 of the lower roller 20 with respect to the movement direction 6 of the continuous layer. The two rotation axes “X”, “Y” are no longer parallel but crossed, substantially forming a letter “X”.

[0089] To this end, as visible in particular in figures 5, 6A, 6B, 7 and 8, the ends

[0090] 11 , 12 of the upper roller 10 are mounted on a respective upright 3, 4 by means of an eccentric rotatable support 31 , 32, rotatable about a respective rotation axis “Z”, “W”, which is eccentric with respect to the rotation axis “X” of the upper roller 10, so that a rotation of the rotatable support 31 , 32 results in a displacement of the respective end 11 , 12 of the rotation axis “X” of the upper roller 10.

[0091] In particular, the rotation axis “Z”, “W” of each rotatable support 31 , 32 is fastened with respect to the respective upright 3, 4 and each rotatable support 31 , 32 houses a respective rolling bearing 31 a, preferably orientable, in turn applied to the respective end 11 , 12 of the upper roller 10.

[0092] Furthermore, in particular, the rotation axes “Z”, “W” of the rotatable supports 31 , 32 are substantially coincident.

[0093] As visible in figures 6A, 6B showing the rotatable support 32 associated with the end 12 of the upper roller 10, the adjustment apparatus 30 comprises, for each rotatable support 31 , 32, at least one actuator 33, 34 configured to perform, preferably continuously, a calibrated rotation of the respective rotatable support 31 , 32 about the respective rotation axis “Z”, “W” so as to change the position of the corresponding end 11 , 12 of the upper roller 10. The actuator 33, 34 is preferably mounted on the respective upright 3, 4.

[0094] In the illustrated embodiment, the actuator 33, 34 is of the manual type. In particular, the actuator 33, 34 is of the screw / nut type, connected to the rotatable support 31 , 32 in an eccentric position with respect to the rotation axis “Z”, “W”. Specifically, each actuator 33, 34 comprises a screw / nut system 35 hinged, by means of pins 36a, 36b, to the rotatable support 31 , 32 and to the respective upright 3, 4, respectively.

[0095] Advantageously, at least one of the upright 3, 4 and the rotatable support 31 , 32 comprises a graduated scale 37 for providing a visual indication of the angular position taken by the rotatable support 31 , 32.

[0096] As visible in figures 6A and 6B, the adjustment apparatus 30 further comprises, for each rotatable support 31 , 32, a fastening system 39 configured to lock the rotatable support 31 , 32 in a determined angular configuration. In the illustrated embodiment, the fastening system 39 comprises at least one slot made in the rotatable support 31 , 32 and at least one tightening member inserted into the slot and tightenable on the upright 3, 4.

[0097] Figure 6A illustrates a neutral configuration of the end 12 of the upper roller 10 and of the rotatable support 32 of the adjustment apparatus 30, in which no adjustment has been made. In this configuration, as clearly visible from the graduated scale 37, the rotatable support 32 takes a neutral configuration with respect to the respective upright 4, in particular a mutual rotation of 0°.

[0098] Whereas figure 6B illustrates a configuration taken by the end 12 of the upper roller 10 and by the rotatable support 32 of the adjustment apparatus 30, following an adjustment made by the adjustment apparatus 30. In this configuration, as clearly visible from the graduated scale 37, the rotatable support 32 takes a rotated configuration with respect to the respective upright 4, in particular a mutual rotation of 30° with respect to the neutral configuration illustrated previously in figure 6A.

[0099] As visible from figures 1 , 2 and 7, the upper roller 10 is a motorized roller associated with a respective engine 15 mounted in a cantilever manner to a respective end 11 of the upper roller 10.

[0100] For this end 11 associated with the engine 15 a support arm 16 is provided, mounted on the respective upright 3 and connected to the end 11 of the upper roller 10 so as to at least partially transfer, onto the support frame 2, the weight of the engine 15.

[0101] In particular, the support arm 16 is adjustably mounted on the upright 3 at least in the aforesaid adjustment plane so as to adapt the position and / or orientation of the support arm 15 to the change in position of the respective end 11 of the upper roller 10.

[0102] The support arm 15 is preferably connected to the upright by means of an eccentric connection 17.

[0103] This eccentric connection 17 has constructional and structural features similar to the rotatable supports 31 , 32 described previously and used for mounting the ends 11 , 12 of the upper roller 10 to the respective uprights 3, 4 of the support frame 2. In other words, the support arm 16 is movable along a circular trajectory substantially comparable to the circular trajectory along which the end 11 of the upper roller 10 is movable. As visible in figures 1 and 2, the unit 1 comprises a scraper 40, mounted on the support frame 2 and associated with the upper roller 10 and configured to create a separation from the surface of the upper roller 10 of the continuous layer exiting the passage space 5.

[0104] In particular, the unit 1 comprises an auxiliary movement apparatus 43 for the scraper 40, interposed between the support frame 2 and the scraper 40 and configured to vary an orientation of the scraper 40 at least in the aforesaid plane parallel to the movement direction of the continuous layer, so as to adapt the orientation of the scraper 40 to the orientation of the rotation axis “X” of the upper roller 10.

[0105] The auxiliary movement apparatus 43 has constructional and structural features similar to the adjustment apparatus 30 of the upper roller 10.

[0106] In particular, the scraper 40 has a first connection end 41 , rotatably constrained to the first upright 3 of the support frame 2, and a second connection end 42, opposite the first connection end 41 , and rotatably constrained to the second upright 4 of the support frame 2.

[0107] The auxiliary movement apparatus 43 of the scraper 40 is configured to move the two connection ends 41 , 42 independently of each other.

[0108] In particular, each connection end 41 , 42 of the scraper 40 is mounted on the respective upright 3, 4 by means of an auxiliary rotatable eccentric support 44, 45, which is rotatable about a respective eccentric rotation axis, so that a rotation of the auxiliary rotatable support 44, 45 results in a displacement of the respective connection end 41 , 42 about the rotation axis of the respective auxiliary rotatable support 44, 45.

[0109] Furthermore, the auxiliary movement apparatus 43 of the scraper 40 preferably comprises a pair of actuators 46, 47, each interposed between the respective upright 3, 4 and the respective auxiliary rotatable support 44, 45 and configured to move the respective auxiliary support 44, 45 about the respective rotation axis.

[0110] As visible in figures 1 and 2, the lower roller 20 is a motorized roller associated with a respective engine 25 mounted in a cantilever manner to a respective end 22 of the lower roller 20. In figure 8, the engine 25 is concealed to show the structural features of the adjustment apparatus 30. Furthermore, as visible from figures 1 , 2, 7 and 8, the unit 1 comprises a movement apparatus 26 for the lower roller 20, configured to vary the width of the passage space 5 so as to change the thickness of the continuous layer exiting the pair of rollers 10, 20, in particular by moving the lower roller 20 towards and away from the upper roller 10.

[0111] In particular, the movement apparatus 26 comprises a first actuator 27 configured to move the end 21 of the lower roller towards / away from the end 11 of the upper roller 10 and a second actuator 28 configured to move the end 22 of the lower roller towards / away from the end 12 of the upper roller 10.

[0112] In an embodiment, the unit 1 , object of the invention, comprises multiple pairs of rollers, e.g., mounted on respective support frames and spaced apart from one another. In this configuration, the web exiting the first stage is detached from the rollers of the first stage and transferred, suspended or resting on a support member (e.g., a conveyor belt), to the pair of rollers of the subsequent stage.

[0113] In a different embodiment, the unit 1 , object of the invention, comprises multiple pairs of rollers configured in a single train of rollers (e.g., formed by three or more tangent rollers) where successive tangency zones define successive laminations and a laminating path. In this configuration, the web is not detached from the rollers but remains stuck to at least one of the rollers, shared by two adjacent laminating stages. In particular, in this configuration, a case is particularly advantageous in which the last roller of the train of rollers serves as the aforesaid upper roller and the previous roller, i.e., tangent to the last roller along the laminating path, serves as the aforesaid lower roller.

[0114] The present invention achieves the set objects by eliminating the drawbacks highlighted in the prior art.

[0115] In this regard, it should be noted that unit 1 as described and / or claimed is capable of ensuring a qualitatively satisfactory finished product.

[0116] This result is achieved, firstly, using an adjustment apparatus 30 for the upper roller 10, which is configured to vary the orientation of the rotation axis “X” of the upper roller 10 with respect to the rotation axis (Y) of the lower roller 20 by moving the ends 11 , 12 of the upper roller 10 so as to compensate for the lack of uniformity of the passage space 5 caused by the bending of the lower roller 20 due to the pressure exerted by the mixture on the lower roller 20, combined with the weight force of the same lower roller 20. Thereby,

[0117] Advantageously, the adjustment apparatus 30, thus, allows equalizing the width of the passage space 5 along the transverse development of the same passage space 5, so as to obtain a continuous plant-based layer with a uniform thickness along the entire width thereof, overcoming thickness variation problems caused by the bending of the rollers 10, 20. A qualitatively superior final product is obtained by minimizing the thickness differences along the width of the continuous layer.

[0118] Secondly, the adjustment apparatus 30 improves the efficiency of the laminating process. By virtue of the dynamic adjustment of the passage space 5, it is possible to rapidly and accurately adapt the laminating process in response to changes in the properties of the mixture, or in the operating conditions. This results in increased productivity and reduced processing waste, with significant financial benefits for the smoking articles industry.

[0119] To summarize, the use of the adjustment apparatus 30 for the upper roller 10 according to the aforesaid technical features ensures a high-quality final product, greater process efficiency and an optimized and versatile structure.

Claims

CLAIMS1. A unit (1 ) for laminating a continuous plant-based layer of the smoking articles industry, comprising:- a support frame (2) having a first upright (3) and a second upright (4);- at least one pair of opposite laminating rollers (10, 20) rotatably mounted on said support frame (2), each pair of rollers (10, 20) comprising an upper roller (10) and a lower roller (20), mutually defining a passage space (5) and configured to laminate a material obtaining a continuous layer; each roller (10, 20) being rotatable about a respective rotation axis (X, Y) and having a first end (11 , 21 ) rotatably supported to the first upright (3) and a second end (12, 22), opposite to the first end (11 , 21 ), rotatably supported to the second upright (4);- an adjustment apparatus (30) for the upper roller (10), acting on the ends (11 , 12) of the upper roller (10) and configured to vary the orientation of the rotation axis (X) of the upper roller (10) with respect to the rotation axis (Y) of the lower roller (20) by moving said ends (1 1 , 12) of the upper roller (10) at least in an adjustment plane parallel to a movement direction (6) of the continuous layer so as to change a width of said passage space (5).

2. A unit (1 ) according to claim 1 , wherein said adjustment apparatus (30) is configured to move said ends (11 , 12) of the upper roller (10) in opposite directions along said adjustment plane.

3. A unit (1 ) according to claim 1 or 2, wherein said adjustment apparatus (30) is configured to move said ends (11 , 12) of the upper roller (10) independently of each other.

4. A unit (1 ) according to any one of the preceding claims, wherein each of said ends (11 , 12) of the upper roller (10) is mounted on the respective upright (3, 4) by means of a rotatable eccentric support (31 , 32), rotatable about a respective rotation axis (Z, W), which is eccentric with respect to the rotation axis (X) of the upper roller (10), so that a rotation of said rotatable support (31 , 32) results in a displacement of the respective end (11 , 12) of the upper roller (10) with respect to the rotation axis (Z, W) ofthe respective rotatable support (31 , 32).

5. A unit (1 ) according to claim 4, wherein the rotation axis (Z, W) of each rotatable support (31 , 32) is fixed with respect to the upright (3, 4) and wherein each rotatable support (31 , 32) accommodates a respective rolling bearing (31 a), preferably orientable, in turn applied to the respective end (11 , 12) of the upper roller (10).

6. A unit (1 ) according to claim 4 or 5, wherein said adjustment apparatus (30) comprises, for each rotatable support (31 , 32), at least one actuator (33, 34) configured to perform, preferably continuously, a calibrated rotation of the rotatable support (31 , 32) about the respective rotation axis (Z, W) so as to change the position of the corresponding end (11 , 12) of the upper roller (10), each actuator (33, 34) preferably being mounted on the respective upright (3, 4).

7. A unit (1 ) according to any one of the preceding claims 4 to 6, wherein said adjustment apparatus (30) further comprises, for each rotatable support (31 , 32), a fastening system (39) configured to lock the rotatable support (31 , 32) in a determined angular configuration, preferably said fastening system (39) comprising at least one slot made in said rotatable support (31 ,32) and at least one tightening member inserted into the slot and tightenable on said upright (3, 4).

8. A unit (1 ) according to any one of the preceding claims 4 to 7, wherein at least one of the upright (3, 4) and the rotatable support (31 ,32) comprises a graduated scale (37) for providing a visual indication of the angular position taken by the rotatable support (31 , 32).

9. A unit (1 ) according to any one of the preceding claims, wherein said upper roller (10) is a motorized roller associated with a respective engine (15) mounted in a cantilever manner to a respective end (11 ) of said upper roller (10), and wherein there is provided, for said end (11 ) associated with the engine (15), a support arm (16) mounted on the respective upright (3) and connected to said end (11 ) of the upper roller (10) so as to at least partially transfer onto said support frame (2) the weight of said engine (15).

10. A unit (1 ) according to claim 9, wherein the support arm (16) is adjustably mounted on the upright (3) at least in said adjustment plane so as to adapt the position and / or orientation of the support arm (16) to the change in position of the respective end (11 ) of the upper roller (10), preferably the support arm (16) being connected to the upright by means of an eccentric connection (17).

11. A unit (1 ) according to any one of the preceding claims, wherein said unit (1 ) comprises a scraper (40), mounted to said support frame (2) and associated with said upper roller (10) and configured to create a separation from the surface of the upper roller (10) of the continuous layer exiting the passage space (5).

12. A unit (1 ) according to claim 11 , wherein said unit (1 ) comprises an auxiliary moving apparatus (43) of the scraper (40), interposed between said support frame (2) and said scraper (40) and configured to vary an orientation of the scraper (40) at least in said plane parallel to the movement direction (6) of the continuous layer so as to adapt the orientation of the scraper (40) to the orientation of the rotation axis (X) of the upper roller (10).

13. A unit (1 ) according to any one of the preceding claims, comprising a lower roller (20) movement apparatus (26) configured to vary the width of said passage space (5) so as to change the thickness of said continuous layer exiting the pair of rollers (10, 20), in particular by means of moving the lower roller (20) towards and away from the upper roller (10).

14. A unit (1 ) according to any one of the preceding claims, comprising at least one measuring device, mounted on the support frame (2) and configured to measure an effective value of the width of said passage space (5) and / or of a thickness of said continuous layer exiting said passage space (5) at least at one point along the transverse development of the passage space (5) and / or of the continuous belt, respectively.

15. A unit (1 ) according to claim 14, when dependent on claim 8, wherein said unit (1 ) comprises a control unit connected to said automatic actuatorand to said at least one measuring device and configured to control said automatic actuator as a function of said at least one measured effective value.

16. A method for laminating a continuous plant-based layer of the smoking articles industry, characterized in that it is performed by means of a unit (1 ) according to any one of the preceding claims.

17. A method according to claim 16, comprising the following steps:- detecting at least one effective thickness value of said continuous layer exiting said passage space (5) and / or the width of said passage space (5) in at least one measuring point by means of at least one measuring device;- adjusting the width of said passage space (5) as a function of said at least one detected effective value, said adjustment being made by varying the orientation of the rotation axis (X) of the upper roller (10) with respect to the rotation axis (Y) of the lower roller (20) by moving the ends (11 , 12) of said upper roller (10) at least in said adjustment plane.

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