EP4646941A1

EP4646941A1 - Trimming device and method for making a rope of the tobacco industry

Info

Publication number: EP4646941A1
Application number: EP25174180.7A
Authority: EP
Inventors: Fausto Mengoli
Original assignee: GD SpA
Current assignee: GD SpA
Priority date: 2024-05-06
Filing date: 2025-05-05
Publication date: 2025-11-12

Abstract

Trimming device (1) for making a rope of the tobacco industry, comprising feed means (2) configured to feed a continuous rope (C) of the tobacco industry along a feed path (L), at a respective feed speed. The device comprises a first trimming disc (10) and a second trimming disc (20), juxtaposed along said feed path (L) so as to engage the continuous rope (C). The trimming discs (10, 20) have respective cutting edges (11, 21) configured to perform a coordinated longitudinal cutting action on the rope (C), so as to separate an excess portion of the rope (C). The device (1) is configured so that the cutting edges (11, 21) of the trimming discs (10, 20) are moved at different tangential speeds.

Description

The present invention relates to the sector of smoking articles and regards a trimming device for making a continuous rope of the tobacco industry, as well as a method for making a continuous rope of the tobacco industry, in particular, implemented by using the aforesaid device.
In the context of the present invention, the term "continuous rope" refers to a long strip of material made of fiber, which is used as a base for producing cigarettes, cigars or other products related to tobacco and/or a tobacco substitute. This continuous rope generally consists of plant fibers (e.g., tobacco) possibly with the addition of additives and suspended, by means of a pneumatic action, over the lower branch of a permeable belt.
The term "trimming" also means a process by means of which a thin amount of material is removed with precision from the continuous rope for purposes of precision, uniformity or finishing thereof. Said removal is typically done by means of a longitudinal cut on the lower surface of the rope, defining, with precision, the thickness of the same rope.
The rope is then fed to a forming unit that wraps the rope with a paper web, obtaining a continuous rod subsequently cut into sections.
In the relevant sector of the present invention, it is known, for example, to form the rope by means of an ascending chimney that releases a flow of fibers upwards, which are held over the lower surface of a permeable conveyor belt, forming a rope having a roughly determined thickness (in the vertical direction).
Next, the rope meets a trimming device comprising a first trimming disc and a second trimming disc, juxtaposed along the feed path, in the position underlying the permeable web, so as to engage the continuous rope: the first trimming disc is rotatable about a first rotation axis according to a first rotation direction while the second trimming disc is rotatable about a second rotation axis, different from the first rotation axis, according to a second rotation direction, opposite to the first rotation direction. In particular, the trimming discs have respective cutting edges configured to perform a coordinated longitudinal cutting action on the rope so as to separate an excess portion of the rope. The cutting edges, moved at the same tangential speed and typically at the feed speed of the continuous rope, remove the excess material from the rope, setting the desired rope weight with elevated precision. Typically, the device further comprises an extraction wheel with blades, arranged close to the zone of tangency between the trimming discs and configured to remove the excess portion of the rope.
Furthermore, in known solutions, it is generally provided to configure the two cutting edges with recesses or interruptions so as to periodically define zones having an increased thickness (subjected to reduced or no trimming action) on the rope, alternating with zones having a reduced thickness, in which the zones having an increased thickness are designed to coincide with the cutting zones of the continuous rod, making a larger filling which prevents the fibers from accidentally exiting the end of the respective cut section. This measure is used, in particular, in the formation of sections of tobacco with a suitable length to form traditional cigarettes.
In order to achieve the positional coincidence between the recesses or interruptions of each of the two trimming discs with the recesses or interruptions of the other trimming disc, the two trimming discs are set in rotation at the same angular speed, in particular, by means of a common operation (single electric motor connected to symmetrical transmission).
The Applicant believes that, despite being clearly operable, the above system has some disadvantages of structural and functional nature, making it improvable.
In particular, since the trimming discs and the continuous rope move at the same tangential speed, the cutting of the excess portion may not be optimal. In fact, instead of having a clean cut, the material could be crushed or pushed sideways by the trimming discs, obtaining a less precise and uniform trimming. In other words, by moving at the same speed, the trimming discs perform an at least partial action of compression of the portion of continuous rope, said action limiting the cutting of the same rope.
Said problems can negatively influence the quality of the material obtained, leading to greater variability in the size of the tobacco particles or the composition of the final product. Imprecise trimming could also influence the combustion or aroma of the final product, compromising the consumer's experience.
Furthermore, said uneven trimming action (with zones having an increased thickness alternating with zones having a reduced thickness) is difficult to implement for segments having a reduced length, for example of the type used in smoking articles without combustion.
Therefore, in said context, the technical task of the present invention is to provide a trimming device for making a continuous rope of the tobacco industry and a method for making a continuous rope of the tobacco industry, which are free from the drawbacks present in the prior art.
Therefore, it is an object of the present invention to provide a trimming device for making a continuous rope of the tobacco industry and a method for making a continuous rope of the tobacco industry, which offer better performance.
It is a further object of the present invention to provide a trimming device for making a continuous rope of the tobacco industry and a method for making a continuous rope of the tobacco industry, which ensure a qualitatively better finished product.
The technical task specified and the objects specified are substantially achieved by a trimming device for making a continuous rope of the tobacco industry having the technical features outlined below. The technical task specified and the objects specified are also achieved by a method for making a continuous rope of the tobacco industry having the technical features outlined below. The method is preferably implemented by means of the aforesaid device.
In particular, the Applicant has found that by rotating the two trimming discs at different tangential speeds in the zone of tangency, an optimal cutting action is performed, maximizing the trimming efficacy, preventing the formation of accumulations or actions of simple compression, improving the quality of the processed rope. Said different tangential speed can be done, according to the invention, by mutually varying the angular speeds of the two trimming discs and/or the diameter of the two trimming discs.
According to the invention, the device comprises feed means configured to feed a continuous rope of the tobacco industry along a feed path, at a respective feed speed.
The feed means preferably comprise a suction conveyor configured to keep the rope suspended.
The device comprises a first trimming disc and a second trimming disc, juxtaposed along the feed path so as to engage the continuous rope.
The trimming discs have respective cutting edges configured to perform a coordinated longitudinal cutting action on the rope so as to separate an excess portion of the continuous rope.
Preferably, the trimming discs each have a smooth, non-serrated cutting edge.
The first trimming disc is rotatable about a first rotation axis according to a first rotation direction, while the second trimming disc is rotatable about a second rotation axis, different from the first rotation axis, according to a second rotation direction, opposite to the first rotation direction. In other words, the two discs are counter-rotating.
The first rotation axis and the second rotation axis are preferably parallel. Alternatively, the first rotation axis and the second rotation axis are incident. The choice between the two embodiments will depend on a series of considerations, including design requirements, space available, easy adjustment and desired operational stability.
The device comprises a movement unit connected to the trimming discs for setting the trimming discs in rotation about the respective rotation axes. The device can further comprise a bladed removal wheel, located in the proximity of said trimming discs, in particular, of a zone of tangency between the trimming discs, and configured to remove the excess portion of the rope.
The applicant has noted that by moving the cutting edges of the trimming discs at different tangential speeds, it is possible to obtain a series of advantages.
Advantageously, since at least one of the cutting edges operates at a different speed with respect to the feeding speed of the continuous rope, the cutting action of the cutting edge is improved. In fact, due to the difference in speed, the aforesaid compression action is reduced to the advantage of the cutting action, which allows a more effective cutting of the material forming the continuous rope.
According to a particularly advantageous embodiment, the cutting edge of the first trimming disc is moved at a first tangential speed which is different from the feed speed of the continuous rope, while the cutting edge of the second trimming disc is moved at a second tangential speed substantially equal to the feed speed of the continuous rope. The cutting edge of the first trimming disc is preferably movable at a tangential speed greater than the feed speed of the continuous rope.
The greater speed of the cutting edge of the first disc with respect to the feed speed of the continuous rope particularly improves the cutting action performed by the trimming discs.
The ratio between the first tangential speed and the second tangential speed preferably has a value between 3 and 1.1
Even more preferably, the ratio between the first tangential speed and the second tangential speed preferably has a value between 1.5 and 1.1.
As will be apparent in the following present description, the aforesaid difference in tangential speed between the cutting edges of the two trimming discs can be obtained by means of different configurations of the trimming device. In particular, as will be more apparent from the following description, the difference between the first tangential speed and the second tangential speed can be obtained by acting on two main operational variables, i.e., by acting on the diameter of the trimming discs and/or by acting on the angular speed of the trimming discs.
According to a first configuration of the device, the trimming discs can have different diameters and be set in rotation at the same angular speed. The first trimming disc preferably has a greater diameter than the second trimming disc.
According to a second configuration of the device, the trimming discs can have the same diameter and be set in rotation at different angular speeds. The first trimming disc is preferably set in rotation at a greater angular speed than the second trimming disc.
According to a third configuration of the device, the trimming discs can have different diameters and be set in rotation at different speeds.
Said configurations all lie within the same inventive concept and allow obtaining the aforesaid difference between the tangential speeds of the cutting edges of the trimming discs. Therefore, the selection of one of the three configurations depends on specific design needs, considering factors like production costs, structural simplicity, space available and further relevant variables, such as easy maintenance, duration in time and operational efficiency.
Specifically, with regard to the second operational variable, i.e., the adjustment and management of the angular speeds of the trimming discs, this can be obtained, in turn, according to different configurations of the device.
According to a first example, the movement unit can comprise a single motor connected to the trimming discs via a mechanical transmission. Said mechanical transmission can be configured so as to set the trimming discs in rotation at the same speed or configured so as to have a first transmission ratio between the motor and the first trimming disc and a second transmission ratio, different from the first, between the motor and the second trimming disc.
According to a second example, the movement unit comprises a first motor connected to the first trimming disc and a second motor connected to the second trimming disc: the first and second motors are controlled or controllable independently of each other to set the respective trimming discs in rotation at equal or different speeds.
The Applicant has observed that by means of said configurations it is thus possible to manage and regulate the difference in tangential speed between the two trimming discs, optimizing the trimming effect (cutting) in the zone of tangency between the discs.
Further features and advantages of the present invention will become more apparent from the indicative, and therefore non-limiting, description of three embodiments of a trimming device for making a rope of the tobacco industry, as well as from a method for making a rope of the tobacco industry, which is preferably implemented by using the aforesaid device according to the invention.
This description will be presented below with reference to the accompanying drawings provided simply by way of indicative and, therefore, non-limiting purposes, in which:

figures 1 and 1A show respective diagrammatic views of a first exemplary embodiment of a trimming device for making a rope of the tobacco industry according to the present invention;
figures 2 and 2A show respective diagrammatic views of a second exemplary embodiment of a trimming device for making a rope of the tobacco industry according to the present invention;
figures 3 and 3A show respective diagrammatic views of a third exemplary embodiment of a trimming device for making a rope of the tobacco industry according to the present invention.

According to the appended figures, reference numeral 1 denotes a trimming device for making a rope of the tobacco industry. A method is described below for making a rope of the tobacco industry according to the present invention, which is preferably implemented by means of the aforesaid device 1.
As visible from the figures, the device 1 comprises feed means 2 configured to feed a continuous rope "C" of the tobacco industry along a feed path "L", at a respective feed speed. In other words, the continuous rope "C" is entered by the feed means 2 along the aforesaid feed path "L", at a respective feed speed.
The movement means 2 preferably comprise a suction conveyor configured to carry the continuous rope "C" so that it is substantially suspended along the feed path "L". Said suction conveyor can be a suction belt of the known type, configured to keep a layer of fiber forming the stated rope "C" suspended, in particular, by means of pneumatic suction.
The device 1 comprises a first trimming disc 10 and a second trimming disc 20, juxtaposed along the feed path "L so as to engage the continuous rope "C".
The trimming discs 10, 20 are preferably arranged below the feed means 2, so as to act on a lower portion of the continuous rope "C".
Structurally, the trimming discs 10, 20 have respective cutting edges 11, 21, configured to perform a coordinated longitudinal cutting action on the rope "C" so as to separate an excess portion of the rope "C". The trimming discs 10, 20 are configured to make a longitudinal cut in the continuous rope "C" so as to separate an excess portion of the continuous rope "C" using the respective cutting edges 11, 21.
The first trimming disc 10 is rotatable about a first rotation axis "X" according to a first rotation direction, while the second trimming disc 20 is rotatable about a second rotation axis "Y", different from the first rotation axis "X", according to a second rotation direction, opposite to the first rotation direction.
As visible from the appended figures, the first rotation axis "X" and the second rotation axis "Y" are parallel.
Alternatively, according to not shown embodiments, the first rotation axis "X" and the second rotation axis "Y" can be incident.
The trimming discs 10, 20 preferably have a respective smooth, non-serrated cutting edge 11, 21. In other words, the cutting edges 11, 21 exert a uniform cutting force along the entire length of the continuous rope "C" so that, after trimming, the continuous rope "C" has a uniform thickness along the entire length thereof.
Said solution is particularly suitable for making "short" sections, e.g. intended for use in smoking articles or for generating aerosols without combustion.
Thus, the device 1 comprises a movement unit 3 connected to the trimming discs 10, 20 to set the trimming discs 10, 20 in rotation about the respective rotation axes "X", "Y".
The device 1 preferably further comprises a bladed removal wheel 4, located in the proximity of the trimming discs 10, 20, in particular, of a zone of tangency between the trimming discs 10, 20, and configured to remove the excess portion of the rope "C".
According to an aspect of the present invention, the device 1 is configured so that the cutting edges 11, 21 of the trimming discs 10, 20 are moved at mutually different tangential speeds.
The cutting edge 11 of the first trimming disc 10 is preferably moved at a first tangential speed different from the feed speed of the continuous rope "C", while the cutting edge 21 of the second trimming disc 20 is moved at a second tangential speed, substantially equal to the feed speed of the continuous rope "C".
The cutting edge 11 of the first trimming disc 10 is preferably moved at a tangential speed greater than the feed speed of the continuous rope "C". In other words, the first tangential speed is greater than the second tangential speed.
The ratio between the first tangential speed and the second tangential speed preferably has a value comprised between 3 and 1.1.
Even more preferably, the ratio between the first tangential speed and the second tangential speed preferably has a value between 1.5 and 1.1.
The three exemplary and thus non-limiting preferred embodiments of the device 1 are described below with particular focus on the movement unit 3.
Figures 1 and 1A show a first possible embodiment of the device 1 according to the invention.
In said embodiment, the first and second trimming discs 10, 20 are equal in diameter and the trimming discs 10, 20 are set in rotation at different angular speeds.
Specifically, the movement unit 3 comprises a single motor 30 connected to the trimming discs 10, 20 via a mechanical transmission 31. The mechanical transmission 31 is configured so as to have a first transmission ratio 31a between the motor 30 and the first trimming disc 10 and a second transmission ratio 31b, different from the first transmission ratio 31a, between the motor 30 and the second trimming disc 20. In other words, the mechanical transmission 31 is configured so as to set the first trimming disc 10 in rotation at a speed greater than the second trimming disc 20.
Therefore, advantageously, according to said embodiment, it is possible to obtain the aforesaid difference in tangential speed between the cutting edges 11, 21 of the two trimming discs 10, 20 by means of an angular speed difference of the trimming discs 10, 20 (with substantially equal diameters).
Figures 2 and 2A show a second possible embodiment of the device 1 according to the invention.
In this embodiment, the first trimming disc 10 differs in diameter with respect to the second trimming disc 20 and the trimming discs 10, 20 are set in rotation at the same angular speed. Specifically, the first trimming disc 10 has a diameter greater than the second trimming disc 20.
The movement unit 3 comprises a single motor 30 connected to the trimming discs 10, 20 via a mechanical transmission 31. The mechanical transmission 31 is configured so as to set the trimming discs 10, 20 in rotation at the same angular speed. In other words, the mechanical transmission 31 is "symmetrical", thus configured so as to have a first transmission ratio 31a between the motor 30 and the first trimming disc 10 and a second transmission ratio 31b, equal to the first transmission ratio 31a, between the motor 30 and the second trimming disc 20. Since the tangential speed is directly proportionate to the diameter of the trimming discs 10, 20 and since the diameter of the first trimming disc 10 is greater than the diameter of the second trimming disc 20, the cutting edge 11 of the first trimming disc 10 will have a tangential speed greater than the cutting edge 21 of the second trimming disc 20.
Therefore, advantageously, according to this embodiment, it is possible to obtain the aforesaid tangential speed difference between the cutting edges 11, 21 of the two trimming discs 10, 20 by means of different diameters of the trimming disc 10, 20 (with the same angular speed of the trimming discs 10, 20).
Figures 3 and 3A show a third possible embodiment of the device according to the invention.
In said embodiment, the first and second trimming discs 10, 20 are equal in diameter and the trimming discs 10, 20 are set in rotation at different angular speeds.
Specifically, the movement unit 3 comprises a first motor 30a connected to the first trimming disc 10 and a second motor 30b connected to the second trimming disc 20. The first motor 30a and the second motor 30b are controlled or controllable, independently of each other, to set the respective trimming discs 10, 20 in rotation at different speeds. The angular speed of the first trimming disc 10 is greater than the angular speed of the second trimming disc 20.
Advantageously, according to this embodiment, it is possible to obtain the aforesaid tangential speed difference between the cutting edges 11, 21 of the two trimming discs 10, 20 by means of an angular speed difference of the trimming discs 10, 20 (with substantially equal diameters).
According to a further embodiment, which is not shown, the first trimming disc 10 differs in diameter with respect to the second trimming disc 20 and the trimming discs 10, 20 are set in rotation at the same angular speed. Specifically, the movement unit 3 comprises a first motor 30a connected to the first trimming disc 10 and a second motor 30b connected to the second trimming disc 20, in which the first motor 30a and second motor 30b are controlled or controllable, independently of each other, to set the respective trimming discs 10, 20 in rotation at equal or, where appropriate, different speeds.
According to further embodiments, which are not shown, the first trimming disc 10 and the second trimming disc 20 differ in diameter and the trimming discs 10, 20 are set in rotation at different angular speeds, preferably with a combination such as to make a different tangential speed between the two trimming discs 10, 20. Specifically, the movement unit 3 can comprise a single motor 30 connected to the trimming discs 10, 20 via a mechanical transmission 31, in which the mechanical transmission 31 is configured so as to set the trimming discs 10, 20 in rotation at the same angular speed, or it can comprise a first motor 30a connected to the first trimming disc 10 and a second motor 30b connected to the second trimming disc 20, in which the first motor 30a and the second motor 30b are controlled or controllable independently of each other so as to set the respective trimming discs 10, 20 in rotation at different speeds.
The present invention achieves the intended purposes by eliminating the drawbacks highlighted in the prior art.
In this regard, it is first noted that the device 1 and the method, as described and/or claimed, ensure improved performance and provide a finished product having improved quality.
In particular, this result is achieved by making an optimal and improved cutting action, determined by the tangential speed difference between the cutting edges 11, 21 of the trimming discs 10, 20.
Furthermore, the optimization of the cutting action results in an improved cleaning condition of the trimming discs, with overall increased reliability and fewer requests for cleaning interventions.

Claims

A trimming device (1) for making a rope of the tobacco industry, comprising:
- feed means (2) configured to feed a continuous rope (C) of the tobacco industry along a feed path (L) at a respective feed speed;

- a first trimming disc (10) and a second trimming disc (20), juxtaposed along said feed path (L) so as to engage said continuous rope (C), said trimming discs (10, 20) having respective cutting edges (11, 21) configured to perform a coordinated longitudinal cutting action on said rope (C) in order to separate an excess portion of said rope (C); said first trimming disc (10) being rotatable about a first rotation axis (X) in a first rotation direction, while said second trimming disc (20) is rotatable about a second rotation axis (Y), distinct from said first rotation axis (X), in a second rotation direction, opposite of the first rotation direction;

- a movement unit (3) connected to said trimming discs (10, 20) to set the trimming discs (10, 20) in rotation about the respective rotation axes (X, Y);
characterized in that said device (1) is configured so that the cutting edges (11, 21) of the trimming discs (10, 20) are moved at different tangential speeds.
The device (1) according to claim 1, wherein the cutting edge (11) of the first trimming disc (10) is moved at a first tangential speed different from the feed speed of the continuous rope (C), preferably at a tangential speed greater than the feed speed of the continuous rope (C), while the cutting edge (21) of the second trimming disc (20) is moved at a second speed substantially equal to the feed speed of the continuous rope (C).
The device (1) according to claim 2, wherein the ratio between the first tangential speed and the second tangential speed is between 3 and 1.1, preferably between 1.5 and 1.1.
The device (1) according to any one of the preceding claims, wherein the movement unit (3) comprises a single motor (30) connected to said trimming discs (10, 20) via a mechanical transmission (31).
The device (1) according to any one of claims 1 to 3, wherein the movement unit (3) comprises a first motor (30a) connected to the first trimming disc (10) and a second motor (30b) connected to the second trimming disc (20); said first and second motors (30a, 30b) being controlled or controllable independently of each other to set said trimming discs (10, 20) in rotation at different speeds.
The device (1) according to claim 4 or 5, wherein said first trimming disc (10) differs in diameter from the second trimming disc (20) and wherein, preferably, said trimming discs (10, 20) are set in rotation at the same angular speed.
The device (1) according to claim 4 or 5, wherein said first and second trimming discs (10, 20) are equal in diameter and wherein said trimming discs (10, 20) are set in rotation at different angular speeds.
The device (1) according to claims 4 and 7, wherein said mechanical transmission (31) is configured so as to have a first transmission ratio (31a) between the motor (30) and the first trimming disc (10) and a second transmission ratio (31b), different from the first (31a), between the motor (30) and the second trimming disc (20).
The device (1) according to any one of the preceding claims, wherein the trimming discs (10, 20) have smooth, non-serrated cutting edges (11, 21).
The device (1) according to any one of the preceding claims, wherein the first rotation axis (X) and the second rotation axis (Y) are incident.
The device (1) according to any one of the preceding claims, further comprising a bladed removal wheel (4), located in the proximity of said trimming discs (10, 20), in particular in the proximity of a zone of tangency between the trimming discs (10, 20), and configured to remove the excess portion of the rope (C).
A method for making a continuous rope of the tobacco industry, implemented, in particular, by a device (1) according to any one of the preceding claims, comprising the following steps:
- feeding a continuous rope (C) of the tobacco industry along a feed path (L) at a respective feed speed;

- making a longitudinal cut in the continuous rope (C) so as to separate an excess portion of said continuous rope (C) using cutting edges (11, 21) of a pair of trimming discs (10, 20) which are juxtaposed along said feed path (L);
characterized in that said cutting edges (11, 21) are moved at different tangential speeds.
The method according to claim 12, wherein the cutting edge (11) of the first trimming disc (10) is moved at a first tangential speed different from the feed speed of the continuous rope (C) and preferably greater than the feed speed of the continuous rope (C), while the cutting edge (21) of the second trimming disc (20) is moved at a second tangential speed substantially equal to the feed speed of the continuous rope (C).
The method according to claim 12 or 13, wherein the ratio between the first tangential speed and the second tangential speed has a value between 3 and 1.1, preferably between 1.5 and 1.
The method according to any one of claims 12 to 14, wherein said trimming discs (10, 20) are set in rotation by a single motor (30) connected to said trimming discs (10, 20) via a mechanical transmission (31).
The method according to any one of claims 12 to 14, wherein the first trimming disc (10) is set in rotation by a first motor (30a), while second trimming disc (20) is set in rotation by a second motor (30b), wherein the first and second motors (30a, 30b) are controlled independently of each other.
The method according to claim 15 or 16, wherein said first trimming disc (10) has a diameter which differs from, in particular is larger than, the diameter of the second trimming disc (20); said trimming discs (10, 20) being set in rotation at the same angular speed.
The method according to claim 15 or 16, wherein said first and second trimming discs (10, 20) are the same in diameter and are set in rotation at different angular speeds.