METHOD AND APPARATUS FOR PRODUCING A FILTER ROD FOR SMOKING ARTICLES

Abstract

An apparatus for continuous production of a filter rod for smoking articles includes a belt conveyor system for advancing a rod of filter material. The belt conveyor system has separate conveyor belts, having respective upper conveying runs arranged one downstream of the other. Speeds of the conveyor belts are controlled according to a predetermined ratio, which controls an axial stretching or compacting effect of the material of the filter rod from the transition between conveyor belts, to influence the characteristics of the produced filter rod. Additional operations can be performed in the area between the upper runs of the conveyor belts, which modify the configuration and/or structure of the filter rod, including shaping, marking or embossing of the filter rod; or filter material may form a filter rod outer layer. The apparatus can produce a filter rod having a coaxial configuration.

Claims

1. A method for continuous production of a filter rod for smoking articles, said method comprising providing a belt conveyor system for advancing a rod of filter material along a forming path, wherein said belt conveyor system comprises at least one endless belt having an upper conveying run for conveying the filter rod, wherein said belt conveyor system comprises at least two separate conveyor belts, having respective upper conveying runs arranged one downstream of the other along said forming path, and wherein in the transition area between the upper runs of said at least two separate conveyor belts, an operation is carried out that modifies configuration and/or structure of the filter rod comprising shaping of the filter rod cross-section and/or embossing and/or marking of a surface of the filter rod and/or supplying filter material to form an outer layer of the filter rod and/or shaping a wrapping sheet of the filter rod.

2. A method according to claim 1, wherein the material forming the filter rod is free of an outer wrapping sheet,

3. A method according to claim 1, wherein speeds of movement of said conveyor belts are controlled according to a predetermined ratio, said predetermined ratio being selected to obtain a controlled axial stretching effect or a controlled axial compacting effect on the material of the filter rod as a result of transition from one conveyor belt to the other, to influence characteristics of the produced filter rod.

4. A method according to claim 1, wherein a rigid wrapping sheet is associated with said filter rod, wherein shaping is imparted to said wrapping sheet.

5. A method according to claim 1, for producing a filter rod having a structure with a coaxial configuration, comprising an outer layer of filter material, the outer layer of filter material being free of a wrapping sheet, and an inner body in the form of a tube of paper or cardboard, or an inner body of filter material, wherein in the transition area between the upper runs of said at least two conveyor belts, an outer layer of filter material is supplied, wherein the downstream conveyor belt is in contact with said outer layer of filter material, and the upstream conveyor belt feeds the inner body comprising said tube of paper or cardboard, or of said inner body of filter material.

6. An apparatus for continuous production of a filter rod for smoking articles, comprising a belt conveyor system for advancing a rod of filter material along a forming path, wherein said belt conveyor system comprises at least one endless belt having an upper conveying run of the filter rod, wherein said belt conveyor system comprises: at least two separate conveyor belts, having respective upper conveying runs arranged one downstream of the other along said forming path, and wherein between the upper runs of said at least two conveyor belts, a filter rod processing station is interposed for carrying out an operation changing a configuration and/or structure of the filter rod, comprising shaping of the filter rod and/or marking a surface of the filter rod and/or feeding of filter material to form an outer layer of the filter rod and/or shaping an outer wrapping sheet of the filter rod.

7. An apparatus according to claim 6, further comprising: a motor associated with said conveyor belts, to control the movement of each conveyor belt, and an electronic control unit for controlling said motor, and configured to implement a predetermined ratio between speeds of movement of said conveyor belts said predetermined ratio being selected to obtain a controlled axial stretching effect or a controlled axial compacting effect on the material of the filter rod as a result of transition from one conveyor belt to the other, so as to influence characteristics of the produced filter rod.

8. An apparatus according to claim 6, wherein the material forming the filter rod is free of an outer wrapping sheet,

9. An apparatus according to claim 6, for producing a filter rod having a structure with a coaxial configuration, comprising an outer layer of filter material, the outer layer of wrapping material being free of a wrapping sheet, and an inner body in the form of a tube of paper or cardboard, or an inner body of filter material, wherein between the upper runs of said at least two conveyor belts a processing station for feeding filter material is interposed, to form said outer layer of filter material, wherein the downstream conveyor belt is in contact with said outer layer of filter material, and the upstream conveyor belt is arranged to advance said inner body comprising said tube of paper or cardboard, or said inner body of filter material.

10. A method according to claim 1, wherein a rigid wrapping sheet is associated with said filter rod, the wrapping sheet comprising a crimped sheet, wherein shaping is imparted to said wrapping sheet to form a circular cross-sectional tube shape in the transition area.

Description

DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

[0020] Further characteristics and advantages of the invention will become apparent from the description that follows with reference to the attached drawings, provided purely by way of non-limiting example, wherein:

[0021] FIG. 1 is a diagrammatic side view of an apparatus according to the prior art known from document U.S. Pat. No. 6,932,752 B2,

[0022] FIG. 2 is a diagrammatic perspective view of a first embodiment of the apparatus according to the invention,

[0023] FIG. 3 is a diagrammatic perspective view of a second embodiment of the apparatus according to the invention,

[0024] FIG. 4 shows an example of a filter rod with a coaxial configuration, which can also be obtained by the method and the apparatus according to the invention, and

[0025] FIG. 5 is a diagram of the two successive operating steps provided in an embodiment of the method according to the invention, in order to produce the product of FIG. 4.

[0026] As indicated above, FIG. 1 illustrates a diagrammatic side view of an apparatus according to the prior art known from document U.S. Pat. No. 6,932,752 B2. This document shows an apparatus usable for producing multi-component filter rods, in which a plurality of filter segments 24 are fed in succession above a tape of wrapping paper 18, which is unwound by a reel 16 and is fed above a belt conveyor system, including a first conveyor belt 56 and a second conveyor belt 58 arranged one downstream of the other. The upper runs of the two endless conveyor belts 56, 58 are engaged by means of guide devices 52, 54, which wrap the upper runs of the belts and the paper sheet 18 fed above them so as to give them a U-shaped cross-section (at the guide device 52) and then a closed circular cross-section (in the second guide device 54). In this known solution, the speed of the downstream belt 58 is expected to be slightly higher than that of the upstream belt 56 in order to ensure the correct tensioning of the paper tape 18 which wraps around the filter segments 24.

[0027] As has already been indicated above, the present invention has been originated from finding that the application of a double-belt conveyor system (known only in the field of equipment for producing multi-component filter rods, of the type illustrated in FIG. 1) to the production of filter rods with no outer wrapping sheet, opens the doors to conceiving an invention that allows, for the first time, the characteristics and the quality of the final product obtained to be influenced in an extremely simple and effective way.

[0028] However, the invention can also be applied to filter rods with which a wrapping sheet is associated, in which case the solution idea described herein is used, for example, to obtain a required shaping of the wrapping sheet (for example, a tubular shape with circular cross-section of a relatively rigid crimped sheet).

[0029] A first example of the apparatus according to the invention is shown in FIG. 2. This figure essentially refers to an apparatus of the type that was the subject of prior European patent EP 2 636 321 B1 by the same Applicant, the main difference being that, in this case, the belt conveyor system includes, instead of a single endless conveyor belt, two endless conveyor belts 1, 2 arranged one downstream of the other. In particular, the two conveyor belts 1, 2 have their upper runs aligned and arranged one downstream of the other, along the forming path F of a filter rod M. The material constituting the filter rod M is fed to the inlet of the forming channel F by means (not shown) of any known type.

[0030] According to a conventional technique (see, for example, EP 2 636 321 B1), the material constituting the filter rod M is advanced through successive processing stations, which may include, for example, a station S1 for vapor insufflation, having the function of activating the hardening agent (triacetin) that was previously added to the filter material M, and subsequent stations S2, S3 for stabilizing the filter rod, of any known type.

[0031] The details of construction of the stations S1, S2, S3 are not provided here, since, as already indicated, these stations can be made according to any known art, and as they do not fall, taken alone, within the scope of the present invention. Furthermore, eliminating these details from the drawings makes them more readily and easily understandable.

[0032] According to the prior art, when crossing each station, the upper tape of each belt meets a guide device that is configured so as to force the belt to deform laterally, in order to assume a U or O cross-section. However, the case is not excluded that this is implemented only for the upstream belt, which forms the filter rod, while the downstream belt can be left undeformed, with a planar configuration.

[0033] Each endless belt is engaged on a plurality of idler rollers R and on a driving wheel P, which actuates the movement of the respective conveyor belt by means of direct frictional contact with it. In the example illustrated in FIG. 2, the two driving wheels P are controlled in rotation by respective electric motors M1, M2 (shown only diagrammatically in the drawings, and optionally including respective gear reducing units), said electric motors being, in turn, controlled by an electronic control unit E.

[0034] It is, however, evident that the driving system for moving the conveyor belts can be completely different from that illustrated in FIG. 2 purely by way of example. For example, a single electric drive motor could be provided with transmission devices that connect the single drive motor to the two conveyor belts, and which can be controlled by the electronic control unit.

[0035] In the first embodiment of the present invention illustrated herein, the rotation speeds of the motor wheels P are controlled according to a predetermined ratio, which can be different from 1. This predetermined ratio is selected so as to influence the characteristics of the filter rod M in the required manner. In particular, the speed of the downstream belt 2 can be increased or decreased with respect to the speed of the upstream belt 1, in order to obtain a controlled axial stretching or a controlled axial compacting of the material M constituting the filter rod. In fact, since the upper runs of the two conveyor belts 1, 2 are in frictional contact with the material M constituting the filter rod, they are able to influence the axial elongation or compacting of the rod during transition from one belt to the other, through the programmed control of the respective transport speeds.

[0036] This result is completely unreachable in known devices of the type shown in FIG. 1, where control of the speed of the conveyor belts can, at most, influence the degree of tensioning of the wrapping tape of the filter segments in a multi-component filter rod.

[0037] Naturally, the friction between the filter rod material and the conveyor belts depends, in particular, on the area of the contact surface between the rod and each belt, and on the roughness of the contact surfaces. The contact area is more extended in the case in which the belt is forced to wrap partially or completely around the rod when crossing the processing stations S1, S2, S3. The belt surface can be prepared with a texture that increases friction. The skilled technician can then take advantage of these arrangements to achieve the desired result.

[0038] FIG. 3 shows an embodiment where the transition area from one conveyor belt to the other can be exploited to carry out any further operation on the filter rod material that requires the absence of the obstacle due to the presence of a conveyor belt. In the case illustrated in FIG. 3, in the transition area from the conveyor belt 1 to the conveyor belt 2, embossing rollers 3 are provided, which give an embossed configuration to the surface of the filter rod. Of course, the presence of two separate conveyor belts makes it possible to take advantage of the transition area from one belt to the other, in order to carry out any kind of further processing, for example, shaping of the filter rod cross-section, or a marking operation, or adding flavoring material, or adding an outer layer of filter material around the filter rod. The provision of two separate conveyor belts, therefore, also provides the possibility to influence the configuration and structure of the product by arranging product processing stations in the transition area between the upper runs of the conveyor belts.

[0039] In the case in which the intermediate station between the two conveyor belts is for feeding a layer of material, it is also possible to envisage that the rod fed along the upstream conveyor belt is provided with a wrapping sheet, as long as the downstream belt is, however, not associated with any wrapping sheet, so that the final rod obtained is, in any case, without any outer wrapping sheet.

[0040] The method according to the invention can also be used, in particular, for producing a filter rod with a coaxial configuration structure, comprising an outer layer of filter material, without an outer wrapping sheet, and an inner body in the form of a paper or cardboard tube, or an inner body of filter material.

[0041] FIG. 4 of the attached drawings shows an example of a filter rod M of this type, with a hollow inner tube T made of paper or cardboard, and an outer layer R1 of filter material, without an outer wrapping sheet.

[0042] FIG. 5 diagrammatically shows two successive steps of the forming method of the rod M of FIG. 4. In a first step, a wrapping tape W of paper or cardboard is carried by a reel RE, and guided and wrapped around a core C to form the tube T. In a second step, produced downstream in the line, filter material is fed around the tube T to produce the outer layer R1, without an outer wrapping sheet. In the illustrated example, the filter material is fed around the tube T by means of two conventional-type feed devices or jets J, which are configured to receive a cord of filter material (illustrated as a cross-section in the drawing) and to feed it with the aid of a flow of compressed air around the tube T. In FIG. 5, for simplicity and clarity, neither the forming channel nor the conveyor belts are illustrated.

[0043] In an embodiment of the method according to the invention, the operational steps illustrated in FIG. 5 are implemented by arranging the two conveyor belts 1 and 2 in association with the two sections indicated with B1 and B2, respectively, in FIG. 5. Therefore, in this case, the upstream conveyor belt 1 has its upper run that receives the tape W above it and advances it through the conventional guide device (not shown), which wraps it in order to form the tube T. The station with feed devices J for the filter material is arranged in the area interposed between the upper runs of the two conveyor belts 1 and 2 (similar to the one shown in FIG. 3). The upper run of the downstream conveyor belt 2 comes into direct contact with the outer layer R1 of filter material, and advances the filter rod thus formed through the forming channel and towards the cutting station.

[0044] The same solution could be adopted by replacing the tube T with an inner body of filter material, fed at the inlet of the forming channel and above the upper run of the conveyor belt arranged further upstream. The inner body of filter material may or may not have a wrapping sheet, but it is understood that this sheet is, however, covered by the outer layer of filter material.

[0045] Also included in the present invention are a method and an apparatus which only rely on the provision of one or more product processing stations in the transition area between the upper runs of the conveyor belts, with equal speeds of the two conveyor belts.

[0046] The electronic control unit E is programmed in any predetermined mode, depending on the characteristics of the final product to be obtained. The apparatus according to the invention thus enables a modification of the characteristics of the final product obtained with extremely simple, effective and inexpensive means.

[0047] Naturally, without prejudice to the principle of the invention, the details of construction and the embodiments may vary widely with respect to those described and illustrated purely by way of example, without departing from the scope of the present invention.