Device and method for shaping the ovality of continuous rods for aerosol-generating articles

Abstract

A device for shaping the ovality of continuous rods for aerosol-generating articles, comprising: a frame (44); a plurality of thrusters (45) supported by the frame (44); a plurality of spring devices (46), each thruster (45) being supported on the frame (44) through a respective spring device (46). The thrusters (45) are disposed around a reference axis (X- X) and each thruster (45) has a working portion (47) facing the reference axis (X-X) and configured to abut against an external surface of a continuous rod (17, 40) for aerosol generating articles (2) passing between the thrusters (45). Each spring device (46) is configured such that the respective thruster (45) is movable towards or away from the reference axis (X-X). Each spring device (46) has a rest position in which a respective elastic force is null. Each spring device (46) exerts the elastic force if it is moved from the respective rest position and away from the reference axis (X-X).

Description

[0001] DEVICE AND METHOD FOR SHAPING THE OVALITY OF CONTINUOUS RODS FOR AEROSOL-GENERATING ARTICLES

[0002] The present disclosure relates to a device and a method for shaping the ovality of continuous rods for aerosol-generating articles. The present disclosure also relates to an apparatus and a process for manufacturing continuous rods for aerosol-generating articles including such device and method.

[0003] An aerosol-generating article, or heat-not-burn consumable, comprises an aerosolgenerating substrate that is heated rather than combusted. The aerosol-generating substrate is, for instance, a tobacco-free herbaceous or plant-based cast sheet or a biodegradable fiber-based material. Typically in such heated aerosol-generating articles an aerosol is generated by the transfer of heat from a heat source to a physically separate aerosol-generating substrate or material. During use, the aerosol-generating article is inserted in an electronic heating device comprising the heat source. Volatile compounds are released from the aerosol-generating substrate by heat transfer from the heat source and are entrained in air drawn through the aerosol-generating article. As the released compounds cool, they condense to form an aerosol.

[0004] An aerosol-generating article is an assembly of different kinds of rod segments or plugs (small cylinders) enclosed in one or more wrapping materials. For instance, one of the plugs is usually made of a compressed sheet of a substrate which generates aerosol when heated. Another plug could be made of polylactic acid which helps to cool down the air heated in the substrate plug before it reaches the consumer. Another plug could be made of cellulose acetate that has a filter function.

[0005] In order to manufacture the plugs of each kind, a main material of the plugs (e.g. aerosol generating substrate or polylactic acid or cellulose acetate), usually provided in band format, is submitted to various pre-treatments, then goes through a “rod forming” stage where the band of material is guided into a converging device and exits as a rod of material having a desired diameter. The rod of material is then wrapped in a continuous band of wrapping paper which is progressively closed on the rod of material. A seam glue line is put on one of the inside edges of the wrapping paper and this edge is fold upon the outside surface the other edge of the wrapping paper. The wrapped rod moves then through a station where a heated bar exerts a top-down vertical pressure on the top of the closed wrapped rod to dry and solidify the seam glue line. The resulting continuous wrapped rod is then cut by a rotating knife in smaller rods which are input to an assembly line.

[0006] In the assembly line, the smaller rods of different materials are cut in a plurality of plugs and the different kinds of plugs are afterwards aligned, abutted and wrapped in a sheet material to form a continuous rod. The sheet material is closed around the different plugs and sealed by depositing a glue line on one of the edges and then heating and pressing the glue line in a manner similar to that disclosed above. The continuous wrapped rod made of different plugs is then cut in smaller rods which are used to manufacture the final consumables, for instance joining a mouthpiece to each smaller rod through a tipping paper.

[0007] Prior art document EP3193642B1 discloses a method and an apparatus for manufacturing aerosol-generating semi-finished products, wherein the following steps are performed along a motion path: feeding a stream of at least three different segments along the motion path, thereby arranging the at least three segments in alternating order, wrapping the stream of at least three segments in a sheet material, thereby forming an endless rod of segments, and cutting the endless rod of segments, thereby separating the endless rod of segments into wrapped segment rods.

[0008] Prior art document GB761754A discloses a machine for measuring the mass of a cigarette rod by means of radiation beams, the rod passes between guides spaced by a distance not exceeding the dimension of the rod between the guides. Then the guides contact the cigarette rod preventing the formation of air spaces and ensuring that as far as possible the shape presented to the radiation gauge is constant.

[0009] In this technical field, it would be desirable to improve the known apparatuses and processes for manufacturing continuous rods for aerosol-generating articles and for manufacturing the aerosol-generating articles, in order to improve the quality of the aerosolgenerating articles and the inhaling experience for the user.

[0010] It would be desirable that the aerosol-generating articles comply as closely as possible with the design features. It would be desirable to assure that a cross section of the continuous rods for aerosol-generating articles and of the aerosol-generating articles obtained therefrom comply with a design cross section.

[0011] It would be especially desirable that the cross section is such that the aerosolgenerating article may be properly housed in an electronic heating device comprising a heat source configured to heat an aerosol-generating substrate part of the article, so to release volatile compounds to be inhaled by the user.

[0012] It would be desirable to ensure a correct operation of the electronic heating device when heating the aerosol-generating substrate so to provide an optimal and consistent inhaling experience to the user.

[0013] It would be also desirable that the cross section of the continuous rods is as close as possible to the design cross section to avoid frictions along the conveying path and during the manufacturing process steps that may damage or break the rods or plugs or that may require the running speed of the continuous rod to be slowed down and so the speed of all the manufacturing line.

[0014] The present disclosure relates to a device for shaping the ovality of continuous rods for aerosol-generating articles.

[0015] The present disclosure also relates to an apparatus for manufacturing continuous rods for aerosol-generating articles. The apparatus may comprise a device for shaping the ovality of continuous rods for aerosol-generating articles.

[0016] The device for shaping the ovality of continuous rods for aerosol-generating articles may comprise: a frame; a plurality of thrusters supported by the frame; a plurality of spring devices. Each thruster may be supported on the frame through a respective spring device. The thrusters may be disposed around a reference axis. Each thruster may have a working portion facing the reference axis and being configured to abut against an external surface of a continuous rod for aerosol-generating articles passing between the thrusters. Each spring device may be configured such that the respective thruster is movable towards or away from the reference axis. Each spring device may have a neutral or rest position in which a respective elastic force is null. Each spring device may exert the elastic force if it is moved from the respective rest position and away from the reference axis.

[0017] The spring devices may be such that the pressure exerted by each thruster on the continuous rod increases as the rod surface in contact with the thruster extends out of an expected perimeter of the continuous rod for aerosol generating articles and may be null when the rod surface is inside the expected perimeter.

[0018] The inventor found that operations carried out on the continuous rods, upstream of the disclosed device for shaping the ovality, may affect the cross section shape of the continuous rods and of the aerosol-generating articles manufactured from said continuous rods. The inventor found that the disclosed device for shaping the ovality is able to restore a desired or design cross section shape and to prevent potential drawbacks correlated to cross section shapes other the design shape.

[0019] The inventor found that shaping the ovality of the continuous rods through the device herein disclosed allows to provide the correct shape, for instance the circular shape, to the continuous rods and to the aerosol-generating articles. This correct shape has a positive visual quality impact on the user. The correct shape allows the aerosol-generating article to be properly housed in the electronic heating device. The correct shape ensures that the aerosol-generating substrate is properly heated by the heat source and that the volatile compounds are properly released. The correct shape allows to optimize the heating process and to provide an optimal and consistent inhaling experience to the user. The inventor also found that ensuring the correct cross section shape, for instance the circular shape, prevents undesired frictions of the continuous rods in the manufacturing line. Possible damages or breakages of the rods may be prevented and the manufacturing speed may be kept optimum.

[0020] Optionally, in the rest positions of the spring devices, the working portions of all the thrusters are radially equi-distant from the reference axis.

[0021] Optionally, each spring device is configured such that the respective thruster is movable along a radial direction with respect to the reference axis.

[0022] In some embodiments, the thrusters are disposed angularly equi-spaced around the reference axis. The thrusters may be N in number and may be disposed each 360 / N degree angle around the reference axis. The thrusters may be disposed according to a radial symmetry with respect to the reference axis.

[0023] Optionally, the thrusters are from two to six in number, for instance the thrusters are four in number.

[0024] One plane perpendicular to the reference axis may intersect the working portions of all the thrusters. Optionally, the working portions of all the thrusters are placed at one plane perpendicular to the reference axis.

[0025] In some embodiments, end stroke elements are operatively coupled to the thrusters and are configured to prevent the thrusters to approach the reference axis beyond a minimum distance and may prevent the thrusters to press the rod inward and to damage said rod. The minimum distance may correspond an external perimeter of the continuous rod.

[0026] In some embodiments, each thruster comprises a roller pivotably connected to the respective spring device around a rotation axis. The working portion may be a peripheral surface of the roller. The peripheral surface may be concave or flat or convex. The peripheral surface may be shaped like an arch of circumference. The arch of circumference may have a radius equal to a radius of the continuous rod for aerosol-generating articles. The rotation axis may be orthogonal to the reference axis. The rotation axes of all the rollers may lie in one plane perpendicular to the reference axis.

[0027] In some embodiments, each thruster comprises a ball partially housed in a housing connected to the respective spring device, the ball being free to rotate in the housing. The working portion is a portion of the ball protruding from the housing.

[0028] The inventor found that the rollers or balls rolling on the continuous rod allow to keep friction on the continuous rod to a minimum and to prevent damages to said rod. The inventor found that the concave surface allows to have a large contact area of the rollers with the continuous rod and to limit the pressure and the risk of compressing too much the rod content.

[0029] According to some embodiments, the spring device comprises at least one spring. The at least one spring may comprise a compression or an extension spring. The at least one spring may be a helical spring. The at least one spring may comprise a pneumatic spring. The at least one spring may comprise a magnetic spring. The magnetic spring may comprise magnets and / or electromagnets. According to some embodiments, the spring device further comprises a damper, for instance an oil damper. According to some embodiments, the at least one spring comprises at least one of: a compression or an extension spring, a magnetic spring, a pneumatic spring.

[0030] The spring device may comprise a piston and a chamber, the piston being movable inside the chamber. The piston may be linked to the thruster and the chamber may be connected to the frame or the piston may be connected to the frame and the chamber may be linked to the thruster.

[0031] The spring device may comprise a linkage, the linkage may comprise a plurality of levers and may be connected to spring. In some embodiments, the levers form at least one articulated quadrilateral. In some embodiments, the spring device comprises the piston and the chamber and also the linkage.

[0032] In some embodiments, a stiffness of the spring device is adjustable and / or a pre-load of the spring device is adjustable and / or the rest position of the spring device is adjustable.

[0033] The inventor found that the stiffness and / or the pre-load and / or the rest position may be adjusted according to the properties of the continuous rod, for instance according to size and materials of the continuous rod.

[0034] The device for shaping the ovality of continuous rods for aerosol-generating articles may also comprise, or may be coupled to, at least one conveyor for conveying the continuous rod for aerosol-generating articles between the thrusters and along a conveying path. The conveying path may be parallel to the reference axis, at least at the frame.

[0035] In some embodiments, the frame is blocked along the conveying path, i.e. any longitudinal movement of the frame along the conveying path is prevented.

[0036] In some embodiments, the frame is rotatably steady, i.e. the frame does not rotate about the reference axis.

[0037] In some embodiments, the frame is rotatable around the reference axis. The device for shaping the ovality of continuous rods for aerosol-generating articles may comprise a motor connected to the frame and configured to rotate the frame about the reference axis. The inventor found that the rotatable frame allows to spread the forces exerted by the thrusters around the continuous rod and to make the shaping action more effective. The inventor found that, if an important radial deformation is detected on a specific radial position, the rotation speed of the frame may be slowed down (possibly down to a full stop) in order for the thrusters to remain a bit longer on the radial position of the rod where the deformation is located.

[0038] In some embodiments, the frame is a ring coaxial to the reference axis. The thrusters may project inward from said ring.

[0039] In some embodiments, at least one sensor is configured to detect a radial deformation of the continuous rod for aerosol-generating articles. In some embodiments, at least one sensor is configured to detect a position and / or a motion of the thrusters. In some embodiments, at least one sensor is configured to detect a working parameter and / or a geometry of the spring device. The at least one sensor may be configured to detect the radial deformation by detecting the position and / or the motion of the thrusters and / or the working parameter and / or the geometry of the spring device.

[0040] The at least one sensor may be selected in the group comprising: strain sensors, capacitive sensors, pressure sensors, optical sensors, cameras.

[0041] A control unit, optionally an electronic control unit, may be operatively connected to the at least one sensor.

[0042] The control unit may be configured to carry out the following procedure: receiving signals from the at least one sensor; deriving a radial deformation of the continuous rod for aerosol-generating articles as a function of the received signals.

[0043] The procedure the control unit is configured to carry out may comprise: identifying any section of the continuous rod for aerosol-generating articles having the radial deformation outside an acceptable range.

[0044] The procedure the control unit is configured to carry out may comprise: adjusting the stiffness of the spring devices as a function of the radial deformation of the continuous rod for aerosol-generating articles. Adjusting the stiffness may be carried out inline, i.e. during operation of the device for shaping the ovality of continuous rods for aerosol-generating articles.

[0045] The procedure the control unit is configured to carry out further may comprise: adjusting the pre-load of the spring devices as a function of the radial deformation of the continuous rod for aerosol-generating articles. Adjusting the pre-load may be carried out inline, i.e. during operation of the device for shaping the ovality of continuous rods for aerosol-generating articles. The procedure the control unit is configured to carry out may comprise: adjusting the rest position of the spring devices as a function of the radial deformation of the continuous rod for aerosol-generating articles. Adjusting the rest position may be carried out inline, i.e. during operation of the device for shaping the ovality of continuous rods for aerosolgenerating articles.

[0046] The procedure the control unit is configured to carry out may comprise: adjusting a linear speed of the continuous rod for aerosol-generating articles as a function of the radial deformation of the continuous rod for aerosol-generating articles. Adjusting the linear speed may be carried out inline, i.e. during operation of the device for shaping the ovality of continuous rods for aerosol-generating articles.

[0047] The procedure the control unit is configured to carry out may comprise: adjusting a rotation speed of the frame around the reference axis as a function of the radial deformation of the continuous rod for aerosol-generating articles. Adjusting the rotation speed may be carried out inline, i.e. during operation of the device for shaping the ovality of continuous rods for aerosol-generating articles.

[0048] The apparatus for manufacturing continuous rods for aerosol-generating articles may comprise at least one conveyor for conveying a continuous rod for aerosol-generating articles along a conveying path. The device for shaping the ovality of continuous rods for aerosol-generating articles may be placed along said conveying path.

[0049] According to some embodiments, the conveyor is configured to convey material in a rod shaped configuration and the apparatus further comprises a wrapping device configured to wrap a wrapper band around the material in rod shaped configuration to form the continuous rod for aerosol-generating articles. The apparatus may also comprise a sealing device configured to join to each other the two longitudinal edges of the wrapper band to form a longitudinal seal. The sealing device may act along the pressing direction and may be configured to press the two longitudinal edges one on the other.

[0050] The device for shaping the ovality of continuous rods for aerosol-generating articles may be placed downstream of the sealing device.

[0051] The inventor found that shaping the ovality of continuous rods may be very effective and useful when carried out just downstream of the sealing device, because the pressure exerted by the sealing device may squeeze the continuous rod and deeply affect the cross section shape of the continuous rod.

[0052] According to some embodiments, the material in a rod shaped configuration comprises a plurality of aerosol-generating plugs aligned along a conveying direction parallel to longitudinal axes of the aerosol-generating plugs. The material in a rod shaped configuration may further comprise a plurality of auxiliary plugs placed between the aerosolgenerating plugs.

[0053] According to some embodiments, the material in a rod shaped configuration comprises a gathered sheet of material.

[0054] According to some embodiments, the apparatus further comprises a cutting device placed downstream of the device for shaping the ovality of continuous rods for aerosolgenerating articles and configured to cut the continuous rod for aerosol-generating articles in a plurality of small rods.

[0055] According to some embodiments, the control unit is configured to carry out the following procedure: identifying faulty small rods coming from the section or sections having the radial deformation outside an acceptable range; sending a warning signal to reject the faulty small rods.

[0056] The present disclosure relates to a method for shaping the ovality of continuous rods for aerosol-generating articles.

[0057] The present disclosure also relates to a process for manufacturing continuous rods for aerosol-generating articles. The process may comprise a method for shaping the ovality of continuous rods for aerosol-generating articles.

[0058] The method for shaping the ovality of continuous rods for aerosol-generating articles may comprise: moving a continuous rod for aerosol-generating articles along a respective longitudinal axis; exerting a plurality of forces on an external surface of the continuous rod for aerosol-generating articles. Said forces may be disposed around the continuous rod for aerosol-generating articles and may be directed towards the longitudinal axis. Said forces may increase as the external surface extends radially out of an expected perimeter of the continuous rod for aerosol generating articles and may be null when the external surface is inside the expected perimeter.

[0059] The expected perimeter may be a circumference and the longitudinal axis passes through a centre of said circumference. The circumference may be a nominal circumference of the continuous rod for aerosol-generating articles.

[0060] In some embodiments, the forces are radially oriented with respect to the longitudinal axis.

[0061] In some embodiments, the forces are disposed angularly equi-spaced around the longitudinal axis. The forces may be N in number and may be disposed each 360 / N degree angle around the longitudinal axis. The forces may be disposed according to a radial symmetry with respect to the longitudinal axis. The forces may be two to six in number, for instance the forces are four in number. In some embodiments, the forces lie in one plane perpendicular to the longitudinal axis.

[0062] In some embodiments, the forces are exerted by rollers or balls rolling on the external surface of the continuous rod for aerosol-generating articles.

[0063] In some embodiments, the continuous rod moves with respect to the forces along the respective longitudinal axis.

[0064] In some embodiments, the forces are rotatably steady, i.e. the forces do not rotate about the longitudinal axis.

[0065] In some embodiments, the method comprises: rotating the forces with respect to the continuous rod and about the respective longitudinal axis, so that the forces act along helical paths on the external surface of the continuous rod for aerosol-generating articles.

[0066] The method may comprise: deriving a radial deformation of the continuous rod for aerosol-generating articles. The method may comprise: identifying any section of the continuous rod for aerosol-generating articles having the radial deformation outside an acceptable range.

[0067] In some embodiments, the method comprises: adjusting a magnitude of the forces as a function of the detected radial deformation. Adjusting the magnitude may be carried out inline, i.e. during shaping the ovality of continuous rods for aerosol-generating articles.

[0068] In some embodiments, the method comprises: adjusting a linear speed of the continuous rod for aerosol-generating articles along the respective longitudinal axis as a function of the detected radial deformation. Adjusting the linear speed may be carried out inline, i.e. during shaping the ovality of continuous rods for aerosol-generating articles.

[0069] In some embodiments, the method comprises: adjusting a rotation speed of the forces around the longitudinal axis as a function of the detected radial deformation. Adjusting the rotation speed may be carried out inline, i.e. during shaping the ovality of continuous rods for aerosol-generating articles.

[0070] The method for shaping the ovality of continuous rods for aerosol-generating articles may be carried out through a device for shaping the ovality of continuous rods for aerosolgenerating articles, wherein such device comprises: a frame; a plurality of thrusters supported by the frame; a plurality of spring devices. Each thruster may be supported on the frame through a respective spring device. The thrusters may be disposed around a reference axis.

[0071] Each thruster may have a working portion facing the reference axis and being configured to abut against an external surface of a continuous rod for aerosol-generating articles passing between the thrusters. Each spring device may be configured such that the respective thruster is movable towards or away from the reference axis. Each spring device may have a rest position in which a respective elastic force is null. Each spring device may exert the elastic force if it is moved from the respective rest position and away from the reference axis.

[0072] The plurality of forces may be exerted through the thrusters of the device.

[0073] When the continuous rod for aerosol-generating articles is shaped in the device, the reference axis and the longitudinal axis may substantially match.

[0074] The process for manufacturing continuous rods for aerosol-generating articles may comprise: conveying material in a rod shaped configuration along a conveying direction; wrapping a wrapper band around the material in a rod shaped configuration and joining to each other two longitudinal edges of the wrapper band to form a longitudinal seal and a continuous rod for aerosol-generating articles. The process for manufacturing continuous rods for aerosol-generating articles may also comprise: pressing the two longitudinal edges of the wrapper band one on the other along a pressing direction.

[0075] The process for manufacturing continuous rods for aerosol-generating articles may also comprise: shaping the ovality of the continuous rod for aerosol-generating articles through to a method for shaping the ovality of continuous rods for aerosol-generating articles, wherein the method comprises: moving a continuous rod for aerosol-generating articles along a respective longitudinal axis; exerting a plurality of forces on an external surface of the continuous rod for aerosol-generating articles. Said forces may be disposed around the continuous rod for aerosol-generating articles and may be directed towards the longitudinal axis. Said forces may increase as the external surface extends radially out of an expected perimeter of the continuous rod for aerosol generating articles and may be null when the external surface is inside the expected perimeter.

[0076] According to some embodiments, conveying the material in a rod shaped configuration comprises: arranging a plurality of aerosol-generating plugs along the conveying direction spaced one from the other and placing a plurality of auxiliary plugs between the aerosol-generating plugs before wrapping the wrapper band around the aerosol-generating plugs and the auxiliary plugs.

[0077] According to some embodiments, conveying the material in a rod shaped configuration comprises: gathering a sheet of material to form the rod shaped configuration.

[0078] The process for manufacturing continuous rods for aerosol-generating articles may also comprise: cutting the continuous rod for aerosol-generating articles in a plurality of small rods after shaping the ovality of continuous rods for aerosol-generating articles.

[0079] According to some embodiments, the process for manufacturing continuous rods for aerosol-generating articles further comprises: identifying faulty small rods coming from the section or sections having the radial deformation outside an acceptable range. The process for manufacturing continuous rods for aerosol-generating articles may also comprise: sending a warning signal to reject the faulty small rods.

[0080] As used in the present description, a “continuous rod for aerosol-generating articles” is one of the continuous rods manufactured in the process for making the aerosolgenerating articles and comprising a material in a rod shaped configuration wrapped in a wrapper band.

[0081] As used in the present description, the “material in a rod shaped configuration” may be material gathered in a continuous rod shape, for instance a gathered or rolled sheet of material, or may be formed by a plurality of plugs aligned along a conveying direction one after the other.

[0082] As used in the present description, “spring device” means any device capable of exerting an elastic force when moved or deformed (through an external force) from a rest or neutral position or configuration of such device.

[0083] As used in the present description, the “elastic force” is the force that allows the spring device to return to its original position / configuration after being moved or deformed.

[0084] The invention is defined in the claims. However, below there is provided a non- exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

[0085] EX1. A device for shaping the ovality of continuous rods for aerosol-generating articles, the device comprising: a frame; a plurality of thrusters supported by the frame; a plurality of spring devices, each thruster being supported on the frame through a respective spring device; the thrusters being disposed around a reference axis and each thruster has a working portion facing the reference axis and configured to abut against an external surface of a continuous rod for aerosol-generating articles passing between the thrusters; wherein each spring device is configured such that the respective thruster is movable towards or away from the reference axis; wherein each spring device has a rest position in which a respective elastic force is null; wherein each spring device exerts the elastic force if it is moved from the respective rest position and away from the reference axis. EX2. The device according to EX1 , wherein, in the rest positions of the spring devices, the working portions of all the thrusters are radially equi-distant from the reference axis.

[0086] EX3. The device according to EX1 or EX2, wherein each spring device is configured such that the respective thruster is movable along a radial direction with respect to the reference axis.

[0087] EX4. The device according to any of EX1 to EX3, wherein the thrusters are disposed angularly equi-spaced around the reference axis.

[0088] EX5. The device according to any of EX1 to EX4, wherein the thrusters are N in number and are disposed each 360 / N degree angle around the reference axis.

[0089] EX6. The device according to any of EX1 to EX5, wherein the thrusters are disposed according to a radial symmetry with respect to the reference axis.

[0090] EX7. The device according to any of EX1 to EX6, wherein the thrusters are from two to six in number, optionally the thrusters are four in number.

[0091] EX8. The device according to any of EX1 to EX7, wherein one plane perpendicular to the reference axis intersects the working portions of all the thrusters and / or the working portions of all the thrusters are placed at one plane perpendicular to the reference axis

[0092] EX9. The device according to any of EX1 to EX8, comprising end stroke elements operatively coupled to the thrusters and configured to prevent the thrusters to approach the reference axis beyond a minimum distance.

[0093] EX10. The device according to any of EX1 to EX9, wherein each thruster comprises a roller pivotably connected to the respective spring device around a rotation axis; optionally each thruster comprises a ball partially housed in a housing connected to the respective spring device, the ball being free to rotate in the housing.

[0094] EX11. The device according to EX10, wherein the working portion is a peripheral surface of the roller; optionally, the working portion being a portion of the ball protruding from the housing.

[0095] EX12. The device according to EX11 , wherein the peripheral surface is concave or flat or convex.

[0096] EX13. The device according to EX12, wherein the peripheral surface is shaped like an arch of circumference.

[0097] EX14. The device according to EX13, wherein the arch of circumference has a radius equal to a radius of the continuous rod for aerosol-generating articles.

[0098] EX15. The device according to any of EX10 to EX14, wherein the rotation axis is orthogonal to the reference axis. EX16. The device according to any of EX10 to EX15, wherein the rotation axes of all the rollers lie in one plane perpendicular to the reference axis.

[0099] EX17. The device according to any of EX1 to EX16, wherein the spring device comprises at least one spring.

[0100] EX18. The device according to EX17, wherein the at least one spring comprises a compression or an extension spring, optionally a helical spring.

[0101] EX19. The device according to EX17 or EX18, wherein the at least one spring comprises a pneumatic spring.

[0102] EX20. The device according to any of EX17 to EX19, wherein the at least one spring comprises a magnetic spring, the magnetic spring comprising magnets and / or electromagnets.

[0103] EX21. The device according to any of EX17 to EX20, wherein the spring device further comprises a damper, optionally an oil damper.

[0104] EX22. The device according to any of EX17 to EX21 , wherein the spring device comprises a piston and a chamber, the piston being movable inside the chamber.

[0105] EX23. The device according to EX22, wherein the piston is linked to the thruster and the chamber is connected to the frame or the piston is connected to the frame and the chamber is linked to the thruster.

[0106] EX24. The device according to any of EX17 to EX23, wherein the spring device comprises a linkage, the linkage comprising a plurality of levers and being connected to spring; optionally the levers form at least one articulated quadrilateral.

[0107] EX25. The device according to any of EX1 to EX24, wherein a stiffness of the spring device is adjustable.

[0108] EX26. The device according to any of EX1 to EX25, wherein a pre-load of the spring device is adjustable.

[0109] EX27. The device according to any of EX1 to EX26, wherein the rest position of the spring device is adjustable.

[0110] EX28. The device according to any of EX1 to EX27, comprising or being coupled to at least one conveyor for conveying the continuous rod for aerosol-generating articles between the thrusters and along a conveying path, the conveying path being parallel to the reference axis, at least at the frame.

[0111] EX29. The device according to EX28, wherein the frame is blocked along the conveying path, i.e. any longitudinal movement of the frame along the conveying path is prevented.

[0112] EX30. The device according to any of EX1 to EX29, wherein the frame is rotatably steady or the frame is rotatable around the reference axis. EX31 . The device according to any of EX1 to EX30, comprising a motor connected to the frame and configured to rotate the frame about the reference axis.

[0113] EX32. The device according to any of EX1 to EX31 , wherein the frame is a ring coaxial to the reference axis and the thrusters project inward from said ring.

[0114] EX33. The device according to any of EX1 to EX32, comprising at least one sensor configured to detect a radial deformation of the continuous rod for aerosol-generating articles or to detect a position and / or a motion of the thrusters.

[0115] EX34. The device according to EX33, wherein the at least one sensor is selected in the group comprising: strain sensors, capacitive sensors, pressure sensors, optical sensors, cameras.

[0116] EX35. The device according to EX33 or EX34, wherein the at least one sensor is configured to detect a working parameter and / or a geometry of the spring device.

[0117] EX36. The device according to any of EX33 to EX35, comprising a control unit, optionally an electronic control unit, operatively connected to the at least one sensor and configured to carry out the following procedure: receiving signals from the at least one sensor; deriving a radial deformation of the continuous rod for aerosol-generating articles as a function of the received signals; optionally identifying any section of the continuous rod for aerosol-generating articles having the radial deformation outside an acceptable range.

[0118] EX37. The device according to EX36 when EX33 is according to EX25, wherein the procedure the control unit is configured to carry out further comprises: adjusting the stiffness of the spring devices as a function of the radial deformation of the continuous rod for aerosol-generating articles; optionally adjusting the stiffness is carried out inline, i.e. during operation of the device for shaping the ovality of continuous rods for aerosol-generating articles.

[0119] EX38. The device according to EX36 when EX33 is according to EX26, wherein the procedure the control unit is configured to carry out further comprises: adjusting the preload of the spring devices as a function of the radial deformation of the continuous rod for aerosol-generating articles; optionally adjusting the pre-load is carried out inline, i.e. during operation of the device for shaping the ovality of continuous rods for aerosol-generating articles.

[0120] EX39. The device according to EX36 when EX33 is according to EX27, wherein the procedure the control unit is configured to carry out further comprises: adjusting the rest position of the spring devices as a function of the radial deformation of the continuous rod for aerosol-generating articles; optionally adjusting the rest position is carried out inline, i.e. during operation of the device for shaping the ovality of continuous rods for aerosolgenerating articles. EX40. The device according to any of EX36 to EX39, wherein the procedure the control unit is configured to carry out further comprises: adjusting a linear speed of the continuous rod for aerosol-generating articles as a function of the radial deformation of the continuous rod for aerosol-generating articles; optionally adjusting the linear speed is carried out inline, i.e. during operation of the device for shaping the ovality of continuous rods for aerosol-generating articles.

[0121] EX41 . The device according to any of EX36 to EX39 when EX33 is according to any of EX30 to EX32, wherein the procedure the control unit is configured to carry out further comprises: adjusting a rotation speed of the frame around the reference axis as a function of the radial deformation of the continuous rod for aerosol-generating articles; optionally adjusting the rotation speed is carried out inline, i.e. during operation of the device for shaping the ovality of continuous rods for aerosol-generating articles.

[0122] EX42. An apparatus for manufacturing continuous rods for aerosol-generating articles, the apparatus comprising the device for shaping the ovality of continuous rods for aerosol-generating articles according to any of EX1 to EX42.

[0123] EX43. The apparatus according to EX42, comprising at least one conveyor for conveying a continuous rod for aerosol-generating articles along a conveying path, wherein the device for shaping the ovality of continuous rods for aerosol-generating articles is placed along said conveying path.

[0124] EX44. The apparatus according to EX42 or EX43, wherein the conveyor is configured to convey material in a rod shaped configuration; wherein the apparatus further comprises: a wrapping device configured to wrap a wrapper band around the material in rod shaped configuration to form the continuous rod for aerosol-generating articles; a sealing device configured to join to each other the two longitudinal edges of the wrapper band to form a longitudinal seal; the sealing device acting along the pressing direction and being configured to press the two longitudinal edges one on the other; wherein the device for shaping the ovality of continuous rods for aerosol-generating articles is placed downstream of the sealing device.

[0125] EX45. The apparatus according to EX44, wherein the material in a rod shaped configuration comprises a plurality of aerosol-generating plugs aligned along a conveying direction parallel to longitudinal axes of the aerosol-generating plugs.

[0126] EX46. The apparatus according to EX45, wherein the material in a rod shaped configuration further comprises a plurality of auxiliary plugs placed between the aerosolgenerating plugs. EX47. The apparatus according to EX44, wherein the material in a rod shaped configuration comprises a gathered sheet of material.

[0127] EX48. The apparatus according to any of EX42 to EX47, further comprising a cutting device placed downstream of the device for shaping the ovality of continuous rods for aerosol-generating articles and configured to cut the continuous rod for aerosolgenerating articles in a plurality of small rods.

[0128] EX49. The apparatus according to EX48, wherein the control unit according to any of EX36 to EX41 is configured to carry out the following procedure: identifying faulty small rods coming from the section or sections having the radial deformation outside an acceptable range; sending a warning signal to reject the faulty small rods.

[0129] EX50. A method for shaping the ovality of continuous rods for aerosol-generating articles, the method comprising: moving a continuous rod for aerosol-generating articles along a respective longitudinal axis; exerting a plurality of forces on an external surface of the continuous rod for aerosolgenerating articles, said forces being disposed around the continuous rod for aerosolgenerating articles and being directed towards the longitudinal axis; wherein said forces increase as the external surface extends radially out of an expected perimeter of the continuous rod for aerosol generating articles and are null when the external surface is inside the expected perimeter.

[0130] EX51. The method according to EX50, wherein the expected perimeter is a circumference and the longitudinal axis passes through a centre of said circumference.

[0131] EX52. The method according to EX51 , wherein the circumference is a nominal circumference of the continuous rod for aerosol-generating articles.

[0132] EX53. The method according to any of EX50 to EX52, wherein the forces are radially oriented with respect to the longitudinal axis.

[0133] EX54. The method according to any of EX50 to EX53, wherein the forces are disposed angularly equi-spaced around the longitudinal axis.

[0134] EX55. The method according to any of EX50 to EX54, wherein the forces are N in number and are disposed each 360 / N degree angle around the longitudinal axis.

[0135] EX56. The method according to any of EX50 to EX55, wherein the forces are disposed according to a radial symmetry with respect to the longitudinal axis.

[0136] EX57. The method according to any of EX50 to EX56, wherein the forces are from two to six in number, optionally the forces are four in number. EX58. The method according to any of EX50 to EX57, wherein the forces lie in one plane perpendicular to the longitudinal axis.

[0137] EX59. The method according to any of EX50 to EX58, wherein the forces are exerted by rollers or balls rolling on the external surface of the continuous rod for aerosolgenerating articles.

[0138] EX60. The method according to any of EX50 to EX59, wherein the continuous rod moves with respect to the forces along the respective longitudinal axis.

[0139] EX61. The method according to any of EX50 to EX60, wherein the forces are rotatably steady, i.e. the forces do not rotate about the longitudinal axis, or wherein the method comprises: rotating the forces with respect to the continuous rod and about the respective longitudinal axis, so that the forces act along helical paths on the external surface of the continuous rod for aerosol-generating articles.

[0140] EX62. The method according to any of EX50 to EX61 , comprising: deriving a radial deformation of the continuous rod for aerosol-generating articles; optionally identifying any section of the continuous rod for aerosol-generating articles having the radial deformation outside an acceptable range.

[0141] EX63. The method according to EX62, comprising: adjusting a magnitude of the forces as a function of the detected radial deformation; optionally adjusting the magnitude is carried out inline, i.e. during shaping the ovality of continuous rods for aerosol-generating articles.

[0142] EX64. The method according to EX62 or EX63, comprising: adjusting a linear speed of the continuous rod for aerosol-generating articles along the respective longitudinal axis as a function of the detected radial deformation; optionally adjusting the linear speed is carried out inline, i.e. during shaping the ovality of continuous rods for aerosol-generating articles.

[0143] EX65. The method according to any of EX62 to EX64 when EX62 is according to EX61 , comprising: adjusting a rotation speed of the forces around the longitudinal axis as a function of the detected radial deformation; optionally adjusting the rotation speed is carried out inline, i.e. during shaping the ovality of continuous rods for aerosol-generating articles.

[0144] EX66. The method according to any of EX50 to EX64, wherein said method is carried out through the device according to any of EX1 to EX41 .

[0145] EX67. The method according to any of EX50 to EX66, wherein the plurality of forces are exerted through the thrusters of the device according to any of EX1 to EX40. EX68. The method according to any of EX50 to EX67, wherein, when the continuous rod for aerosol-generating articles is shaped in the device according to any of EX1 to EX40, the reference axis and the longitudinal axis substantially match.

[0146] EX69. A process for manufacturing continuous rods for aerosol-generating articles, the process comprising the method for shaping the ovality of continuous rods for aerosolgenerating articles according to any of EX50 to EX68.

[0147] EX70. The process according to EX69, comprising: conveying material in a rod shaped configuration along a conveying direction; wrapping a wrapper band around the material in a rod shaped configuration and joining to each other two longitudinal edges of the wrapper band to form a longitudinal seal and a continuous rod for aerosol-generating articles; pressing the two longitudinal edges of the wrapper band one on the other along a pressing direction; shaping the ovality of the continuous rod for aerosol-generating articles through to the method according to any of EX49 to EX66.

[0148] EX71. The process according to EX70, wherein conveying the material in a rod shaped configuration comprises: arranging a plurality of aerosol-generating plugs along the conveying direction spaced one from the other and placing a plurality of auxiliary plugs between the aerosol-generating plugs before wrapping the wrapper band around the aerosol-generating plugs and the auxiliary plugs.

[0149] EX72. The process according to EX70, wherein conveying the material in a rod shaped configuration comprises: gathering a sheet of material to form the rod shaped configuration.

[0150] EX73. The process according to any of EX69 to EX72, further comprising: cutting the continuous rod for aerosol-generating articles in a plurality of small rods after shaping the ovality of continuous rods for aerosol-generating articles.

[0151] EX74. The process according to EX73 when the method for shaping the ovality of continuous rods for aerosol-generating articles is according to any of EX62 to EX65, further comprising: identifying faulty small rods coming from the section or sections having the radial deformation outside an acceptable range; sending a warning signal to reject the faulty small rods.

[0152] Examples will now be further described with reference to the figures in which:

[0153] Figure 1 shows a schematic view of an apparatus for manufacturing aerosolgenerating articles;

[0154] Figure 2 an enlarged part of the apparatus of Figure 1 making a continuous rod; Figures 3A - 3D show a sequence of steps carried out in the enlarged part of Figure

[0155] 2;

[0156] Figure 4 is an exploded view of an aerosol-generating article made in the apparatus of Figure 1 ;

[0157] Figures 5A, 5B and 5C show views of an embodiment of a device for shaping the ovality of continuous rods for aerosol-generating articles implemented in the apparatus of Figure 1 ;

[0158] Figures 6A and 6B show views of another embodiment of the device of Figures 5A and 5B;

[0159] Figures 7A and 7B show views of another embodiment of the device of Figures 5A and 5B;

[0160] Figures 8 shows a portion of another embodiment of the device of Figures 5A and 5B.

[0161] An apparatus 1 for manufacturing aerosol-generating articles 2 is shown in Figure 1. One example embodiment of aerosol-generating articles 2 is depicted in the exploded view of Figure 4 and comprises (from left to right in Figure 4): a front plug 3 (solid plug), an aerosol-generating plug 4, a tubular plug 5 (hollow plug, for instance of cellulose acetate), a fine tubular plug 6 (similar to the tubular plug 5 but with a thinner wall) and a filter plug 7 (mouthpiece filter usually made of tow). Each plug has a wrapping of its own (not detailed Figure 4) helping to contain properly their content. A tipping paper 8 connects the filer plug 7 to the rest of the plugs, and the front plug 3, aerosol-generating plug 4, tubular plug 5 and fine tubular plug 6 are wrapped together into a wrapper paper 9.

[0162] The aerosol-generating plug 4 comprises an aerosol generating substrate 10 made of a sheet of aerosol generating material 11 gathered in a continuous rod shape. The aerosol-generating material may comprise reconstituted tobacco or tobacco-free herbaceous or plant-based material or a biodegradable fiber-based material.

[0163] The apparatus 1 for manufacturing aerosol-generating articles 2 comprises (Figures 1 and 2) a reel-carrier 12 carrying the sheet of aerosol generating material coiled in a reel 13. The sheet of aerosol-generating material 11 unwound from the reel-carrier 13 is fed along a feeding path in a feeding direction “F”. Downstream of the reel-carrier 12, with respect to the feeding direction “F”, the apparatus 1 comprises a folding device 14 which is configured to move the sheet of aerosol-generating material from a flat configuration (upstream of the folding device 14) to a gathered rod-shaped configuration (downstream of the folding device 14). The folding device 14 may be shaped like a tapered funnel.

[0164] A wrapping device 15 placed downstream of the folding device 14 is configured to wrap the wrapper paper 9, unwound from a respective wrapper paper reel 16, around the gathered sheet of aerosol generating material 11 in order to obtain a continuous aerosolgenerating rod 17.

[0165] A sealing device 18 is configured to join to each other the two longitudinal edges of the wrapper paper 9 to form a longitudinal seal on the continuous aerosol-generating rod 17. In Figures 1 and 2, the wrapping device 15 and the sealing device 18 are schematically represented as two blocks. Anyway, the wrapping device 15 and the sealing device 18 may be integrated in one station comprising a plurality of tools, for instance as depicted in Figures 3A to 3D.

[0166] Figure 3A shows a U-shaped guide or moving tape 19 which, through possible further tools not shown, folds a first of two longitudinal edges of the wrapper paper 9 on the generating substrate 10 gathered in continuous rod shape. The U-shaped guide or moving tape 19 and the possible further tools are part of the wrapping device 15.

[0167] Then a glue applicator 20, part of the sealing device 18, applies a glue line 21 along the inside of a second of the two longitudinal edges of the wrapper paper 9 (Figure 3B). Then said second longitudinal edge is folded on the first longitudinal edge (Figure 3C).

[0168] A pressing device 22, part of the sealing device 18 and placed downstream of the glue applicator 20, acts along a pressing direction “P” and presses the two longitudinal edges one on the other while heating and solidifying the glue line 21 (Figure 3D), thus forming the continuous aerosol-generating rod 17. In the example embodiment, the pressing direction “P” is vertical. The pressing device 22 spreads the glue and may squeeze the continuous aerosol-generating rod 17. In the disclosed embodiment, the pressing device 22 comprises a heating bar provided with heating elements, for instance resistive heating elements.

[0169] Downstream of the wrapping device 15 and the sealing device 18, the continuous aerosol-generating rod 17 is cut by a cutter “C” in a plurality of elongated aerosol-generating rods 17’ which are then transferred to a plurality of knives 23, for instance rotating knives, configured to cut the plurality of elongated aerosol-generating rods 18’ in the aerosolgenerating plugs 4 detailed above.

[0170] The aerosol-generating plugs 4 are transferred to a first feeder 24. The first feeder 24 is a rotating drum, i.e. a drum rotated through a motor not shown, and the aerosolgenerating plugs 4 are placed and retained on a peripheral portion of the rotating drum with their longitudinal axes perpendicular to a rotation axis of the rotating drum.

[0171] The aerosol-generating plugs 4 retained on the peripheral portion through suction devices of the first feeder 24, not shown, and are conveyed to a merging feeder 25, in particular to an upper branch 26 of a belt conveyor merging feeder 25 (comprising two pulleys with a closed loop belt that rotates about them rotated by a respective motor) which is placed below the first feeder 24. A peripheral speed of the first feeder 24 and a speed of the upper branch 26 of the belt conveyor merging feeder 25 are such that the aerosolgenerating plugs 4 are put on said upper branch 26 with a small spacing between them and along their longitudinal axes.

[0172] A second feeder 27 is positioned above the merging feeder 25 and is located downstream of the first feeder 24 with respect to a direction of movement of the upper branch 26 of the belt conveyor merging feeder 25. The second feeder 27 is configured to carry the plurality of tubular plugs 5 coming from a respective production line 100 and to place said tubular plugs 5 on the upper branch 26 of the belt conveyor merging feeder 25 between the aerosol-generating plugs 4. Each tubular plug 5 is put between two aerosolgenerating plugs 4 with a small space between them.

[0173] The second feeder 27 is a rotating drum, i.e. a drum rotated through a motor not shown, and the tubular plugs 5 are placed and retained on a peripheral portion of the rotating drum with their longitudinal axes perpendicular to a rotation axis of the rotating drum.

[0174] The first feeder 24, the second feeder 27 and the merging feeder 25 make up a combiner device 28 which is configured to combine different plugs (in this example embodiment: the aerosol-generating plugs 4 and the tubular plugs 5).

[0175] The upper branch 26 of the merging feeder 25 conveys the plurality of aerosolgenerating plugs 4 and the plurality of tubular plugs 5 towards a wrapping station 29. A transfer assembly 30 is operatively placed between the merging feeder 25 and the wrapping station 29. The transfer assembly 30 comprises a plurality of transfer conveyors, for instance rotating drums. In the example embodiment of Figure 1 , the transfer assembly 30 comprises a first rotating drum 31 followed by a second rotating drum 32. A third rotating drum 33 is located between the second rotating drum 32 and the wrapping device 30.

[0176] The aerosol-generating plugs 4 and the tubular plugs 5 are placed and retained on peripheral portion of the first, second and third rotating drums 31 , 32, 33. The aerosolgenerating plugs 4 and the tubular plugs 5 are transferred from the first rotating drum 31 to the second rotating drum 32 and to the third rotating drum 33. The third rotating drum 33 puts the aerosol-generating plugs 4 and the tubular plugs 5 on the wrapping station 29.

[0177] The wrapping station 29 comprises a wrapping conveyor 34. The wrapping conveyor 34 is a belt conveyor comprising two pulleys with a closed loop belt that rotates about them. One of the two pulleys is rotated by a respective motor. The wrapping station 29 further comprises a wrapper band feeder 35 configured to feed a wrapper band 36 on an upper branch 37 of the wrapping conveyor 34. The wrapper band feeder 35 of Figure 1 comprises a reel-carrier 38 carrying the wrapper band 36 coiled in a reel 39. The wrapper band 36, uncoiled from the reel 39, is laid on the upper branch 37 of the wrapping conveyor 34 and moved together with said upper branch 37 along a conveying direction. The third rotating drum 33 is placed above a first end of the wrapping conveyor 34 and is configured to release the aerosol-generating plugs 4 and the tubular plugs 5 on the wrapper band 36 supported and moved by the upper branch 37 of the wrapping conveyor 34.

[0178] A peripheral speed of the third rotating drum 33 and a speed of the upper branch 37 of the wrapping conveyor 34 are such that the aerosol-generating plugs 4 and the tubular plugs 5, once on the wrapper band 36 placed on the upper branch 37, are approached and abutted once against the other.

[0179] The wrapping station 29 further comprises a wrapping device 15’ and a sealing device 18’ which may be the same or similar to the wrapping device 15 and sealing device 18 of Figure 2 or may comprise a plurality of tools similar to the tools depicted in Figures 3A to 3D.

[0180] The wrapping device 15’ and the sealing device 18’ wrap the wrapper band 36 around the aerosol-generating plugs 4 and the tubular plugs 5 and form a continuous rod 40 with a longitudinal seal. In the sealing device 18’, the two longitudinal edges of the wrapped band are pressed one on the other while heating and solidifying the glue (like in Figure 3D) and the continuous rod 40 may be squeezed.

[0181] Downstream of the wrapping device 15’ and the sealing device 18’, a cutting device 41 , for instance a rotating knife, cuts the continuous rod 40 into a plurality of segments 42, wherein each segment 42 may be the final aerosol-generating article 2 or may be a part of the aerosol-generating article 2.

[0182] For instance, the segment 42 comprises one aerosol-generating plug 4 and one tubular plug 5 wrapped in the wrapper paper 9, which is a portion of the wrapper band 36, as manufactured through the example apparatus 1 of Figure 1. For instance, the segment 42 comprises the front plug 3, the aerosol-generating plug 4, the tubular plug 5 and the fine tubular plug 6 wrapped in the wrapper paper 9 of Figure 4. Each segment 42 is then joined to the filter plug 7 to obtain the final aerosol-generating article 2.

[0183] The reel-carrier 12 with the reel 13 of aerosol generating material 11 , the folding device 14, the wrapper paper reel 16 of wrapper paper 9, the wrapping device 15 and the sealing device 18 of Figure 1 are part of a first apparatus for manufacturing continuous rods for aerosol-generating articles and said continuous rod is the continuous aerosol-generating rod 17. The wrapping station 29 is a second apparatus for manufacturing continuous rods for aerosol-generating articles and said continuous rod is the continuous rod 40. A device 43 for shaping the ovality of continuous rods for aerosol-generating articles is placed downstream of the sealing device 18 of the first apparatus for manufacturing continuous rods. Such device 43 is schematically represented in Figures 1 and 2.

[0184] A first example embodiment of the device 43 for shaping the ovality of continuous rods for aerosol-generating articles is shown in Figures 5A, 5B and 5C. The device 43 of these Figures 5A and 5B is configured to shape the ovality of the continuous aerosolgenerating rod 17 coming from the sealing device 18 of the first apparatus for manufacturing continuous rods.

[0185] The device 43 comprises a frame 44 shaped like a ring coaxial to a reference axis X- X matching with a longitudinal axis of the continuous aerosol-generating rod 17. Four thrusters 45 are supported by the frame 44, protrude radially inward from the ring and towards the reference axis X-X. The four thrusters 45 are disposed according to a radial symmetry with respect to the reference axis X-X, angularly equi-spaced of 90°. Each thruster 45 is connected to the frame 44 through a spring device 46. The spring devices 46 of Figures 5A and 5B are helical springs. A first end of each helical spring is attached to the frame 44 and a second opposite end is connected to the respective thruster 45. Each thruster 45 is a roller pivotably connected to the second end of the respective helical spring around a rotation axis Y-Y orthogonal to the reference axis X-X. The rollers are free to rotate about their rotation axes Y-Y and the rotation axes Y-Y of all the rollers lie in one plane perpendicular to the reference axis X-X.

[0186] The continuous aerosol-generating rod 17 coming from the sealing device 18 goes through the ring and between the rollers. Peripheral surfaces of the rollers face the reference axis X-X and are configured to abut against an external surface of the continuous aerosol-generating rod 17 passing between them. The peripheral surface, when facing the reference axis X-X and abutting against the external surface, rolls on the continuous aerosol-generating rod 17 and defines a working portion 47 of the thruster 45.

[0187] The working portions 47 of all the thruster 45 touch the external surface of the continuous aerosol-generating rod 17 along lines or bands. The lines are placed at one plane perpendicular to the reference axis X-X or one plane perpendicular to the reference axis X-X intersects all the bands.

[0188] Figure 5C, shows that the roller is made up of a central cylinder and two opposite truncated cones such that a cross section of the peripheral surface configured to touch the continuous aerosol-generating rod 17 comprises a central flat surface 48 and two opposite inclined surfaces 49. In other embodiments, the peripheral surface may be concave, flat or convex. The peripheral surface may be shaped like an arch of circumference provided with a radius equal or close to a radius of the continuous rod for aerosol-generating articles. In other embodiments, not shown in the drawings, each thruster comprises a ball partially housed in a housing connected to the respective spring device, the ball is free to rotate in the housing. The working portion is a portion of the ball protruding from the housing.

[0189] Each spring device 46 has a neutral or rest position in which a respective elastic force is null and is configured such that, if the thruster is pushed radially outwards, i.e. away from the neutral or rest position and away from the reference axis X-X, the helical spring is compressed and exerts the elastic force that pushes towards the reference axis X-X.

[0190] The four thrusters 45 are arranged such that, in the rest positions, the working portions 47 of the thrusters 45 lie on an expected perimeter of the aerosol-generating rod 17 or close to the expected perimeter, such that a pressure exerted by each thruster 45 on the aerosolgenerating rod 17 is null when the rod surface is on or inside the expected perimeter. The pressure exerted by each thruster 45 on the aerosol-generating rod 17 increases as the rod surface in contact with the thrusters 45 extends out of the expected perimeter.

[0191] The expected perimeter is typically a nominal circumference of the aerosol-generating rod 17 and may have a diameter of some millimetres, for instance 6 mm to 8 mm.

[0192] The device 43 for shaping the ovality may also comprise end stroke elements, not shown in the figures, which are operatively coupled to the thrusters 45 and are configured to prevent the thrusters 45 to approach the reference axis X-X beyond a minimum distance, wherein the minimum distance corresponds the external perimeter of the aerosolgenerating rod 17. The end stroke elements prevent the thrusters 45 to press the rod inward and to damage said rod.

[0193] A conveyor, not shown in figures 1 and 2, is configured to convey the aerosolgenerating rod 17 along a conveying path matching with its longitudinal axis. The ring is steady, i.e. any longitudinal movement of the frame along the conveying path and around the conveying path is prevented, and the aerosol-generating rod 17 is guided through the ring and between the thrusters 45.

[0194] The device 43 for shaping the ovality is configured to carry out a method for shaping the ovality of continuous rods for aerosol-generating articles.

[0195] While the aerosol-generating rod 17 moves along the respective longitudinal axis and between the thrusters 45, said thrusters 45 exert respective radial elastic forces on the external surface of the aerosol-generating rod 17 if its cross section is outside the expected perimeter. The more the cross section extends outside the expected perimeter, the greater the elastic forces will be.

[0196] The forces, like the thrusters 45, lie in one plane perpendicular to the longitudinal axis and are disposed according to a radial symmetry with respect to the reference axis X-X, angularly equi-spaced of 90°. If the aerosol-generating rod 17 has squeezed or ovalized portions, due for instance to the action of the pressing device 22 working upstream, the elastic forces squeeze the aerosol-generating rod 17 at said ovalized portion and restore the circular shape.

[0197] In the variant embodiment shown in figures 6A and 6B, the frame 44 disclosed above is still blocked along the reference axis X-X but said frame 44 is configured to rotate around the reference axis X-X. The frame 44 comprises a rail 50 fashioned on a perimeter of the ring. The device 43 for shaping the ovality comprises a fixed supporting structure 51 having idle wheels 52. The idle wheels 52 are engaged with the rail 50 and rolls on the rail 50 such that the frame 44 hangs from the fixed supporting structure 51. The ring has an external annular groove 53 into which a portion of a transmission belt 54 is fit. The transmission belt 54 is also wound around a pulley 55 connected to and driven in rotation by a motor, not shown. In other embodiments, not shown, the ring has an external gear engaged with a pinion of the motor.

[0198] The frame 44 and the thrusters 45 are rotated around the reference axis X-X while the aerosol-generating rod 17 moves along the respective longitudinal axis such that the forces act along helical paths E on the external surface of the aerosol-generating rod 17, as shown in figure 6B.

[0199] In the variant embodiment shown in figures 7A and 7B, the spring device 46 comprises a linkage 51 provided with a plurality of levers arranged to form two articulated quadrilaterals joined by rotation shafts. One extremity of two levers carry one of the rollers which is idly pivoted to said extremities about the rotation axis Y-Y. An extension spring 53 connects opposing vertices of the articulated quadrilaterals. In case the thruster 45 is moved radially outwards, the extension spring will extends, thus generating an elastic force towards the reference axis X-X.

[0200] The linkage 51 is connected to the frame 44 through a L-shaped part 52. A radial position of the L-shaped part 52 on the frame 44 may be changed. Indeed, the L-shaped part 52 is provided with a plurality of holes 54 and a screw 55 is engageable in one of the holes 54 to attach the L-shaped part 52 to the frame 44 according to a plurality of radial positions. This way, the rest position of the spring device 46 may be adjusted.

[0201] The spring of figures 5A, 5B, 6A, 6B, 7A, 7B may be changed with other having a different stiffness and / or may be pre-loaded.

[0202] Figure 8 shows another embodiment of the spring device 46 which comprises a piston 56 moving inside a chamber 57 of a cylinder 58 (like a shock absorber). A fork 59 is connected to the piston 56 and carries one of the thrusters 45, i.e. one of the rollers pivoted to the fork 59 to rotate about the rotation axis Y-Y. Oil is contained in the chamber 57 and the piston 56 has passages for the oil between two volumes delimited by the piston 58 in the chamber 57. The chamber 57 is mounted on the frame 44. In a variant embodiment, not shown the piston 58 is connected to the frame 44 and the chamber 57 is linked to the thruster 45.

[0203] The chamber 57 is in fluid connection with a reservoir 60 through a pipe. The reservoir 60 houses a floating piston 61 which parts the reservoir 60 in an upper chamber for the oil and a lower chamber 62 containing a high pressurized gas, for instance nitrogen, and connected to a gas pump 63 through a respective pipe 64. Pressure of the gas in the lower chamber 62 is adjustable (increased or decreasd) through the gas pump 63. The spring device 46 of figure 8 is therefore a pneumatic spring (gas) provided with a damper (oil).

[0204] In other embodiments, not shown in the drawings, the spring device 46 comprises a magnetic spring provided with magnets and / or electromagnets. For instance, a piston / chamber structure comprises a magnet mounted on the piston and another magnet mounted on the chamber. The magnets are arranged with poles pushing each other apart. If using electromagnets, a strength of the magnetic field may be adjusted.

[0205] In other embodiments, not shown in the drawings, the spring device 46 comprises a combination of the cited spring elements (compression or extension spring, magnetic spring, pneumatic spring) with or without damping and / or a combination of structures, for instance the piston / chamber structure is combined with the linkage.

[0206] The device 43 for shaping the ovality further comprises one or more sensors 65 configured to detect a radial deformation of the continuous aerosol-generating rod 17 by detecting a position and / or a motion of the thrusters 45 or a working parameter and / or a geometry of the spring device 46.

[0207] In figures 5A, 7A and 8 the sensors 65 are only schematically represented. For instance, the sensor 65 is a capacitor sensor having one part made by an electret attached to the thruster 45 and another part fixed to the frame 44. For instance, the sensor 65 is a strain sensor measuring an elongation of the spring. For instance, the sensor 65 is an optical sensor or a camera focusing and capturing markers on the thruster 45. In the embodiment of figure 8, the sensor 65 is a pressure sensor capable of capturing the gas pressure in the lower chamber 62. An increase in the gas pressure means that the thruster 45 is moving toward the chamber 57.

[0208] The sensor or sensors 65 are operatively connected to an electronic control unit 66 (schematically shown only in figure 8). The electronic control unit 66 may be the control unit of the apparatus 1 for manufacturing aerosol-generating articles 2 or a control unit of the device 43 for shaping the ovality.

[0209] The electronic control unit 66 is configured and / or programmed to receive signals from the sensors 65, to elaborate the signals and to derive a radial deformation or ovality of the continuous aerosol-generating rod 17 from said signals. For instance, the radial deformation or ovality of the continuous aerosol-generating rod 17 is derived from the capacitances of the capacitor sensors or the signals from the strain sensors or the pressures in the chambers 57 or the movement of the markers detected through the optical sensors or cameras, since all these values are related to the positions of the thrusters 45 determined by the shape of the continuous aerosol-generating rod 17.

[0210] The electronic control unit 66 is configured to compare the derived radial deformation or ovality to an acceptable value or range and to discriminate if the derived radial deformation or ovality is below or above the acceptable value or inside or outside the acceptable range.

[0211] The electronic control unit 66 is configured to identify any non-compliant section of the continuous aerosol-generating rod 17 having the radial deformation higher than the acceptable value or outside the acceptable range.

[0212] For instance, the apparatus 1 for manufacturing continuous rods for aerosolgenerating articles comprises a time clock running during manufacturing and the electronic control unit 66 links the derived radial deformations or ovalities to the time. Since the running speed of the continuous aerosol-generating rod 17 is known, the electronic control unit 66 is able to identify said non-compliant sections and the elongated aerosol-generating rods 17’ cut by the cutter “C” and / or the aerosol-generating plugs 4 cut by the knives 23 coming from said non-compliant sections. When faulty elongated aerosol-generating rods 17’ and / or aerosol-generating plugs 4 (faulty small rods) are identified, the electronic control unit 66 issue a warning signal that can be employed to automatically reject said items and / or warn the personnel.

[0213] In some embodiments, the electronic control unit 66 is also operatively connected to actuators, not shown, coupled to the spring devices 43 and configured to change the stiffness (for instance the gas pressure in the lower chamber 62 of figure 8 or the current feeding the magnets), the pre-load or the rest position of the spring devices 43 as a function of the radial deformation or ovalities of the continuous aerosol-generating rod 17. These changes may be carried out between one production cycle and the next one or inline, i.e. during manufacturing the aerosol-generating articles 2. This way, a magnitude of the forces exerted by the thrusters 45 is changed as a function of the detected radial deformation.

[0214] In some embodiments, the electronic control unit 66 is also operatively connected to the conveyor that moves the continuous aerosol-generating rod 17 to adjust a linear speed V of said aerosol-generating rod 17 as a function of the radial deformation or ovalities. In the variant embodiment of figures 6A and 6B, the electronic control unit 66 is connected and controls the motor configured to rotate the frame 44 and may adjust the rotation speed R of the frame 44 as a function of the radial deformation of the continuous the aerosolgenerating rod 17. Adjustments of the linear and / or rotation speeds V, R may be carried out between one production cycle and the next one or inline, i.e. during manufacturing the aerosol-generating articles 2.

[0215] A device 43 for shaping the ovality similar or identical to the one disclosed above and shown in figures 5A, 5B, 6A, 6B, 7A, 7B and 8 is also placed downstream of the sealing device 18’ of the second apparatus for manufacturing continuous rods. This further device 43 is configured to shape the ovality of the continuous rod 40 coming from the sealing device 18’ of the second apparatus for manufacturing continuous rods, i.e. from the wrapping station 29.

[0216] Features and operation of this further device 43 may be the same as the features and operation disclosed above. Through this further device 43, the electronic control unit 66 is capable of identifying and discarding faulty segments 42 (faulty small rods).

[0217] For the purpose of the present description and of the appended claims, except where otherwise indicated, all numbers expressing amounts, quantities, percentages, and so forth, are to be understood as being modified in all instances by the term "about". Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein. In this context, therefore, a number A is understood as A ± 5 percent of A. Within this context, a number A may be considered to include numerical values that are within general standard error for the measurement of the property that the number A modifies. The number A, in some instances as used in the appended claims, may deviate by the percentages enumerated above provided that the amount by which A deviates does not materially affect the basic and novel characteristic(s) of the claimed invention. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein.

Claims

CLAIMS1. A device for shaping the ovality of continuous rods for aerosol-generating articles, the device comprising: a frame (44); a plurality of thrusters (45) supported by the frame (44); a plurality of spring devices (46), each thruster (45) being supported on the frame (44) through a respective spring device (46); the thrusters (45) being disposed around a reference axis (X-X) and each thruster(45) has a working portion (47) facing the reference axis (X-X) and configured to abut against an external surface of a continuous rod (17, 40) for aerosol generating articles (2) passing between the thrusters (45); wherein each spring device (46) is configured such that the respective thruster (45) is movable towards or away from the reference axis (X-X); wherein each spring device (46) has a rest position in which a respective elastic force is null; wherein each spring device (46) exerts the elastic force if it is moved from the respective rest position and away from the reference axis (X-X).

2. The device of claim 1 , wherein, in the rest positions of the spring devices(46), the working portions (47) of all the thrusters (45) are radially equi-distant from the reference axis (X-X).

3. The device of claim 1 or 2, wherein the thrusters (45) are disposed angularly equi-spaced around the reference axis (X-X).

4. The device of any of claims 1 to 3, wherein one plane perpendicular to the reference axis (X-X) intersects the working portions (47) of all the thrusters (45).

5. The device of any of claims 1 to 4, wherein each thruster (45) comprises a roller pivotably connected to the respective spring device (46) around a rotation axis (Y-Y) and the working portion (47) is a peripheral surface of the roller; the rotation axis (Y-Y) being orthogonal to the reference axis (X-X).

6. The device of claim 5, wherein the peripheral surface is concave, optionally the peripheral surface is shaped like an arch of circumference.

7. The device of any of claims 1 to 6, comprising a motor connected to the frame (44) and configured to rotate the frame (44) about the reference axis (X-X).

8. The device of any of claims 1 to 7, comprising: at least one sensor (64) configured to detect a position and / or a motion of the thrusters (45); a control unit (65) operatively connected to the at least one sensor (64) and configured to carry out the following procedure: receiving signals from the at least one sensor (64); deriving a radial deformation of the continuous rod (17, 40) for aerosol generating articles (2) as a function of the received signals.

9. A method for shaping the ovality of continuous rods for aerosol generating articles, the method comprising: moving a continuous rod (17, 40) for aerosol generating articles (2) along a respective longitudinal axis; exerting a plurality of ferees (Fn) on an external surface of the continuous rod (17, 40) for aerosol generating articles, said forces (Fn) being disposed around the continuous rod (17, 40) for aerosol generating articles (2) and being directed towards the longitudinal axis; wherein said forces (Fn) increase as the external surface extends radially out of an expected perimeter of the continuous rod (17, 40) for aerosol generating articles (2) and are null when the external surface is inside the expected perimeter.

10. The method of claim 9, wherein the expected perimeter is a circumference and the longitudinal axis passes through a centre of said circumference.

11. The method of claim 9 or 10, wherein the forces (Fn) are radially oriented with respect to the longitudinal axis.

12. The method of any of claims 9 to 11 , wherein the continuous rod (17, 40) moves with respect to the forces (Fn) along the respective longitudinal axis.

13. The method of any of claims 9 to 12, comprising: rotating the forces (Fn) with respect to the continuous rod (17, 40) and about the respective longitudinal axis, so that theforces act along helical paths on the external surface of the continuous rod (17, 40) for aerosol generating articles (2).

14. The method of any of claims 9 to 13, wherein the forces (Fn) are exerted by rollers rolling on the external surface of the continuous rod (17, 40) for aerosol generating articles (2).

15. The method of any of claims 9 to 14, further comprising:■ deriving a radial deformation of the continuous rod (17, 40) for aerosol generating articles (2);■ adjusting a magnitude of the forces (Fn) as a function of the detected radial deformation; and / or■ adjusting a rotation speed of the forces (Fn) around the longitudinal axis as a function of the detected radial deformation; and / or ■ adjusting a linear speed (V) of the continuous rod (17, 40) for aerosol generating articles (2) along the respective longitudinal axis as a function of the detected radial deformation.

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