Field of the invention

The present invention relates to the technical sector of the production of articles of the tobacco industry.

In particular, the present invention relates to a method and a machine for producing a sub-unit of a smoking article, which may be, for example, a smoking article of the type configured to generate aerosols by heating up, preferably without burning, or an electronic cigarette. The present invention also relates to a sub-unit of a smoking article preferably obtained with the aforesaid method and/or machine.

In this context, it is particularly important, in order to ensure the quality of the finished product, to ensure the correct containment and retention of the active material, i.e. the aerosol-generating material, both during the production process and during the use of the article.

State of the prior art

The known production methods involve producing a smoking article formed by a bar body (such as a filter or a heating element) and a tubular segment in wrapping material, which is subsequently filled with the aerosol generator element.

However, this solution is not very suitable for guaranteeing the integrity of the article, in particular as it does not allow ensuring the correct retention of the aerosol-generating element, i.e. the active portion of the smoking article, inside the tubular segment during suction by a user.

The above implies that during use of the smoking article, the aerosolgenerator element could leave its sub-unit until it enters and transits adjacent ones, affecting the correct operation of the product.

In particular, there may be an unwanted leakage of the aerosol generator element, or of any other filling material present inside the smoking article, under the effect of suction by the user.

Summary of the invention

In this context, the technical task underlying the present invention is to propose a method and a machine for producing a sub-unit of a smoking article and of a sub-unit thus obtained that overcome at least some of the aforementioned drawbacks of the prior art. In particular, it is an object of the present invention to provide a method and a machine for producing a sub-unit of a smoking article and a sub-unit thus obtained capable of optimizing the production process while improving the quality and stability of the finished achievable product.

The specified technical task and the specified objects are substantially achieved by a method and a machine for producing a sub-unit of a smoking article, and by a sub-unit thus obtained comprising the technical characteristics set out in one or more of the attached claims.

According to the present invention, a method is shown for producing a subunit of a smoking article that involves the provision of a tubular segment of the tobacco industry, in particular a segment which internally has a through-duct that terminates in end openings of the tubular segment.

The method also involves applying a connecting strip that has at least one weakened zone (the meaning of which will be better clarified below) on the outer surface of the tubular segment in such a way that the connecting strip has a first portion superposed on the tubular segment covering a first angular portion of the outer surface of the tubular segment, leaving uncovered a second angular portion of the outer surface of the tubular segment, and at least one second portion axially projecting with respect to a respective end of the tubular segment, with the aforesaid weakened zone between the first portion and the second portion of the connecting strip.

The second portion of the connecting strip is then folded transversely to the first portion (at the said weakened zone) to form a closing wall which at least partly closes the end opening of the tubular segment.

Advantageously, the method of the present invention makes it possible to produce sub-units of a smoking article having closing walls which prevent any filling materials present in the smoking article from passing from one sub-unit to another, and which are at the same time simple to make.

The present invention also relates to a method for producing a smoking article which comprises the steps of:

- providing a plurality of sub-units of smoking articles wherein at least one of said sub-units is an intermediate sub-unit made in accordance with the method for producing a sub-unit of a smoking article in accordance with the present invention;

- juxtaposing the plurality of sub-units along a main direction of extension so that the closing wall of the intermediate sub-unit is interposed between the tubular segment of the intermediate sub-unit and a sub-unit adjacent thereto.

In this way, the closing wall is interposed between adjacent sub-units thus preventing the transit of any filling materials contained in the sub-units that form the smoking article.

The present invention also relates to a machine for producing a sub-unit of a smoking article that comprises a conveyor drum configured to feed a succession of double-length tubular wrappers of the tobacco industry; a feeding unit of a continuous web; a unit for weakening a continuous web; a gumming device configured to apply an adhesive substance on at least one first portion, preferably a central portion, of the continuous web; a pair of cooperating cutting drums to separate a succession of connecting strips from a front end of the continuous web; and an applicator drum.

In particular, the applicator drum is configured to receive a succession of double-length tubular wrappers from the conveyor drum and to transport them to an application station wherein each double-length tubular segment receives a corresponding connecting strip from one of the cutting drums.

The coupling of the double-length tubular segment with the connecting strip occurs in such a way that the first portion of each connecting strip is applied between opposite ends of a respective double-length tubular segment and that the connecting strip has a pair of second portions axially projecting with respect to the end of the tubular segment.

The machine also comprises folding means located at or downstream of the applicator drum to fold each second portion of the connecting strips in such a way as to make a closing wall, which at least partly closes respective ends of the tubular segment.

Preferably, the machine is configured to carry out a method according to the present invention.

The dependent claims, incorporated herein by reference, correspond to different embodiments of the method and the machine according to the present invention.

The present invention also relates to a sub-unit of a smoking article (preferably obtained with the method and/or the machine indicated above), comprising a tubular segment of the tobacco industry internally having a through- duct terminating in end openings of the tubular segment. The sub-unit also comprises a connecting strip applied longitudinally to the tubular segment and comprising a first portion, a second portion and at least one weakened zone between the first portion and the second portion, The first portion of the connecting strip is superposed on the outer surface of the tubular segment, and has a transverse dimension such as to cover a first angular portion of the outer surface of the tubular segment, leaving a second angular portion of the outer surface of the tubular segment uncovered, and the second portion defines an extension of the first portion and is folded transversely to the first portion to form a closing wall which at least partly closes at least one end opening of the tubular segment

Advantageously, the sub-unit of a smoking article according to the present invention is simple to manufacture.

Brief description of the drawings

Further characteristics and advantages of the present invention will become clearer from the description indicative, and therefore non-limiting, of a preferred but not exclusive embodiment of a method and a machine for producing a sub-unit of a smoking article, as illustrated in the attached drawings wherein:

- Figures 1A-E show a particular embodiment of a succession of steps relating to the method of the present invention and a sub-unit according to the present invention;

- Figure 2 shows a schematic diagram of the main components of a machine for producing sub-units of smoking articles.

Detailed description of the invention

The present invention relates to a method for producing sub-units that can be used for producing smoking articles, of which some significant steps according to a particular embodiment are shown sequentially in the attached Figures from 1 A to IE.

The method involves preparing a tubular segment 1 of the tobacco industry.

In particular, this tubular segment 1 internally has a through-duct which ends in respective end openings.

In other words, the tubular segment 1 defines therein a duct, suitable - if necessary - of also performing the function of a containment chamber for a filling material for the tobacco industry, which flows into the open ends of the tubular segment itself 1.

By way of non-limiting example, a filling material such as an aerosolgenerating material, tobacco granules, loose tobacco or in another form, flavoring material (for example, microcapsules containing a flavoring liquid) or filtering agent (activated carbon, silica gel or other agents known in the reference sector) or a material with a cooling effect (such as PLA in granules) could therefore be inserted inside the through-duct.

The method, therefore, involves applying on the outer surface of the tubular segment 1 a connecting strip 2, having at least one weakened zone 20, so that this connecting strip 2 has a first portion 2a superposed on the tubular segment 1 covering a first angular portion of its outer surface, leaving uncovered a second angular portion of this outer surface of the tubular segment, with the aforesaid weakened zone 20 between the first portion 2a and the second portion 2b of the connecting strip 2. The aforesaid weakened zone 20 may extend even partially along the first portion 2a and/or the second portion 2b of the connecting strip 2 (as illustrated in Figures ID, IE).

The connecting strip 2 is also applied in such a way as to present at least one second portion 2b, defined by an extension of the first portion 2a, axially projecting with respect to a respective end of the tubular segment 1.

The second portion 2b of the connecting strip 2 is then folded transversely to the first portion 2a, preferably perpendicularly at the relative weakened zone 20, to form a closing wall which at least partly closes the end opening of the tubular segment 1.

Connecting strip 2 means a strip of sheet material preferably defined by four sides parallel two by two, or having a rectangular perimeter. This expedient guarantees optimal manufacturing simplicity and little or no scrap material, as will be better clarified below. This means that even at the weakened zone 20, the connecting strip 2 has a constant profile, or rather, not tapered or skewed.

The connecting strip 2 may comprise or be made of metal material, for example, aluminum or stainless steel (of suitable thickness).

Preferably, the connecting strip 2 is made of aluminum or comprises aluminum: this material, in fact, guarantees thermal conductivity and ductility with a low "elastic return" following the relative folding.

Alternatively, the connecting strip 2 is made of or comprises: paper, paper/plastic polylaminates or paper laminated with metal (e.g. aluminum).

Alternatively, the connecting strip 2 is made of or comprises: cellulose, linen, or cotton. Weakened zone 20 means an area of the connecting strip 2 wherein the folding of this is facilitated, previously subjected to a specific processing/treatment and, for example, capable of reducing its thickness and/or creating folding lines, patterns or other types of templates (as will be better specified below). The weakened zone 20 preferably extends for the entire transverse extension of the relative connecting strip 2.

The presence of the weakened zone 20 facilitates the application of the connecting strip 2, reducing processing times and increasing the quality of the final product.

It should be noted that an equivalent method to the one mentioned above is to apply the connecting strip 2 first with its second portion 2b to the respective end of the tubular segment 1 with the first portion 2a protruding from the respective end and then folding, again at the said weakened zone 20, the first portion 2a of the connecting strip 2 longitudinally on the outer surface of the side wall of the tubular segment 1.

In other words, the method involves coupling a connecting strip 2 to a tubular segment 1 in such a way that this has a part, the first portion 2a, superposed on the side wall of the tubular segment 1 and a part, the second portion 2b, which extends from the first portion 2a and is folded in such a way as to form a closing wall which prevents the passage of the filling material once the sub-unit is assembled in a smoking article.

In particular, the closing wall provides a barrier that prevents the passage of any filling material of the smoking article wherein the sub-unit will be introduced through the end opening of the tubular segment 1.

At the same time, the closing wall is such as to allow the passage of air and/or gas and/or aerosol through the end of the sub-unit, in particular towards a user during the use of the smoking article in which this sub-unit is inserted.

In accordance with a first possible embodiment, the folding step of the second portion 2b forms a wall defining a complete covering of the respective end opening.

In accordance with this embodiment, the second portion is at least partially made of porous material.

To ensure or increase the permeability of the closing wall to air and/or gases, it is possible to make a plurality of holes or perforations on the continuous web 3 before cutting, in particular on portions of the continuous web 3 intended to make each second portion 2b.

The making of holes or perforations in the continuous web 3 may be carried out, for example, using a laser light source.

Alternatively, the step of folding the second portion 2b may create a wall defining a partial covering of the respective end opening.

In other words, the method of the present invention involves producing the closing wall in such a way that two distinct situations can occur alternatively: a first situation wherein the second portion 2b is folded to achieve complete closure of the end opening of the tubular segment 1 on which it is folded, and a second situation wherein the second portion 2b is folded to achieve only partial closure of the end opening of the tubular segment 1 on which it is folded.

If the closing wall completely covers the end opening of the tubular segment 1, in order to ensure the correct flow of air and/or gas and/or aerosol through the sub-unit, at least the second portion 2b of the connecting strip 2 is made in porous material and/or provision is made for making a plurality of holes or perforations suitable for increasing the permeability of the closing wall to air or gases.

In other words, if the closing wall is such as to completely close the access to the duct defined internally by the tubular segment 1, the second portion is made or processed in such a way as to allow - in any case - the passage of air and/or gas and/or aerosol.

If, on the other hand, the closing wall only partially covers the end opening of the tubular segment 1, the correct inflow of air and/or gas and/or aerosol through the sub-unit is guaranteed by those portions of the end opening which remain uncovered, therefore the second portion 2b may be made of a material impermeable to air.

However, it is possible that the second portion is - in any case - made of porous material and/or that a plurality of holes or perforations suitable for increasing the permeability of the closing wall to air or gases is made even if this closing wall only makes a partial closure of the end opening of the tubular segment 1.

In particular, the folding step is carried out by means of at least one fixed folding device arranged along a feed trajectory of the second portion 2a.

Preferably, the folding takes place while the tubular segment 1 equipped with the relative connecting strip 2 is moved transversely by means of a movement drum equipped with peripheral suction seats.

In accordance with a particular aspect of the present invention, the folding step comprises a pre-folding step and a folding step that are distinct from each other. In the pre-folding step, the second portion 2b of the connecting strip 2 is folded, again at the weakened zone 20, transversely to the first portion 2a to obtain an inclined orientation of the second portion 2b with respect to the first portion 2a.

In the subsequent folding step, the second portion 2b is pressed against the respective end of the tubular segment 1 defining the closing wall.

In particular, the pre-folding step is carried out at or immediately downstream of the application zone of the connecting strip to the respective tubular segment 1, preferably by means of a respective movable folding device.

Furthermore, the pre-folding step may be carried out while the tubular segment 1 equipped with the relative connecting strip 2 is moved transversely by means of a drum equipped with peripheral suction seats, in particular, the movable folding device can be mounted on said drum.

In particular, the movable folding device may be moved axially or radially with respect to the drum on which it is mounted.

If the movement is axial, the movable folding device has an inclined front surface which is substantially counter-shaped to the inclined configuration to be obtained for the second portion 2a.

If, on the other hand, the movement is radial, the movement of the movable folding device is stopped once the second portion 2a assumes the required prefolding angle.

The method also involves applying the connecting strip 2 to the tubular segment 1 in such a way that the first portion extends between two opposite ends of the tubular segment.

In particular, the connecting strip 2 is applied along the entire length of the tubular segment 1.

The first portion 2a is then applied in such a way as to fully cover the first angular portion of the tubular segment 1 by completely covering it from one end to the other. In this case, the connecting strip 2 comprises two weakened zones 20, one at a different end of the tubular segment 1 (see Figures 1A-1E). According to an alternative not illustrated, the connecting strip 2 is applied to cover half of the first angular portion of the tubular segment 1.

Preferably, each connecting strip 2 is made by feeding a continuous web 3 formed with a suitable material, and then cutting it in such a way as to create a succession of connecting strips 2, which can then be applied to respective tubular wrappers 1. Preferably, the cutting of the continuous web 3 is such as to obtain a succession of connecting strips 2 having a rectangular perimeter as defined above. It is clear that in this preferred embodiment where each connecting strip 2 is a strip of sheet material defined by four sides parallel two by two (i.e. it has a rectangular perimeter), the relative implementation starting from a continuous web 3 guarantees an optimal manufacturing simplicity of the connecting strips 2 themselves, and reduced or no scrap material. On the contrary, if the perimeter (or rather, the profile) of each connecting strip were not rectangular, the relative manufacturing process would be more complicated and scrap material would most likely be generated.

Prior to the cutting step, the continuous web 3 is suitably weakened to determine at least one weakened zone 20 thereon, so that, following the cutting step, each connecting strip 2 comprises at least one weakened zone 20, as previously described. The step of weakening the continuous web 3 may take place by embossing and/or by laser and/or by creasing the continuous web 3. The weakening step may take place after feeding the continuous web 3 and before cutting the latter (as in the case illustrated), or it could be carried out previously, i.e. the continuous web 3 could be fed with the weakened zones 20 already made on the web (situation not illustrated).

The continuous web 3 may have such dimensions so that it is possible to generate a succession of connecting strips 2 side by side, that is to say that the continuous web 3 has a width equal to the overall length of the connecting strips 2. Alternatively, the continuous web 3 may have dimensions such that it is possible to generate a succession of connecting strips 2 in line with each other, that is to say that the continuous web 3 has a maximum width equal to the maximum width of the connecting strips 2.

With particular reference to the attached Figure 1 A, the aforesaid weakening step determines two weakened zones 20 on the continuous web 3, each having a linear and continuous development over the entire extension of the continuous web 3 itself (essentially, two continuous strips parallel to each other). This aspect ensures that all the connecting strips 2 obtained by cutting the continuous web 3 have corresponding weakened zones 20 in a particularly simple way. It is clear that the weakening step could also create different patterns on the continuous web 3 in order to obtain the weakened zones 20 with respect to the one illustrated.

Before cutting the continuous web 3, therefore, prior to the separation of the individual connecting strips 2, and preferably after the step of weakening the continuous web 3, it is possible to carry out a gumming process thereon wherein an adhesive substance is applied to the continuous web 3, preferably in a portion thereof intended to form the first portion 2a of the individual connecting strips 2.

The method therefore involves applying an adhesive substance to the continuous web 3, in particular in accordance with a specific predetermined pattern.

The gumming process may also be carried out on those portions of the continuous web 3 intended to form the second portions 2b of the connecting strips 2.

Preferably, if also applied to the second portions 2b, the adhesive layer is applied according to a model that traces the overlapping profile of the second portion 2b with the edge of the tubular segment 1, leaving instead free the part of the second portion 2b that is directly facing the duct defined by the tubular segment 1. To promote the correct application and adhesion of the connecting strip 2 to the tubular segment 1, it is possible to subject the sub-unit to a rolling process prior to the folding of the second portion 2b of the connecting strip 2.

In particular, this rolling method is performed by using a fixed rolling bed while the tubular segment 1 equipped with the relative connecting strip 2 is moved transversely by means of an applicator drum 105 equipped with peripheral suction seats.

According to a particular aspect of the present invention, in the step of preparing the tubular segment 1, a tubular segment of double length 11 is arranged.

The term double-length tubular segment 11 means a tubular segment which has a length such that it can be divided into two distinct parts of equal length, and suitable for making two respective sub-units 1 of a smoking article.

Still in accordance with this embodiment, the step of applying the connecting strip 2 is performed by applying a connecting strip 2 in such a way that it has a first portion 2a superposed on a side wall portion of the tubular segment 11 and extending between its two opposite ends, and one pair of second portions 2b axially projecting with respect to respective opposite ends of the double-length tubular segment 11.

There is also a step of cutting the double-length tubular segment 11, equipped with the applied and folded connecting strip 2, along its mid-plane "M", thus obtaining two sub-units of the tobacco industry abutting at the mid-plane “M” of the double tubular segment 11.

Advantageously, the present invention achieves the proposed objects by overcoming the drawbacks of the prior art, by providing the user with a method for making a sub-unit of a smoking article which guarantees the structural integrity of the finished product in which the sub-units thus produced will be inserted.

This result is obtained by applying a connecting strip to the tubular segment that is folded to create a closing wall that prevents the passage of any filling materials through the closed end of the sub-unit.

Furthermore, applying a connecting strip that covers only a well-defined angular portion of the outer wall of the tubular segment 1 allows using only the quantity of material necessary for forming a closing wall, which will suitably occlude the end opening of the sub-unit.

Finally, the presence of at least one weakened zone 20 on the connecting strip 2 facilitates the folding operations of the extended connecting strip 2, increasing the quality of the final product.

The present invention also relates to a method for producing a smoking article which comprises a step of preparing a plurality of sub-units of smoking articles, wherein at least one of these sub-units is an intermediate sub-unit made in accordance with the method for making of a sub-unit of a smoking article described above.

The method for producing the smoking article also involves juxtaposing the plurality of sub-units along a main direction of extension so that the closing wall of the intermediate sub-unit is interposed between the tubular segment 1 of the intermediate sub-unit and a sub-unit adjacent thereto.

The method described here also involves wrapping an outer covering material in tubular form around the sub-units, so that the first portion 2a of the connecting strip 2 is arranged and held between the respective tubular segment 1 and the outer covering material, preferably the first portion 2a of the connecting strip 2 is glued to the tubular segment 1.

In this way, the closing wall is interposed between the end openings of adjacent sub-units, thus preventing the transit of the filling material of the smoking article between one sub-unit and another.

The present invention also relates to a machine for producing sub-units of smoking articles, in particular by implementing a method in accordance with what has been described above.

In Fig. 2, the numerical reference 100 generically indicates a machine for producing a smoking article in accordance with the present invention, indicated below in the present description simply as the machine 100. The machine 100 a conveyor drum 101 configured to feed a succession of double-length tubular segments 11 of the tobacco industry.

As discussed above, the double-length tubular wrappers 11 are intended to be cut in successive steps of the production process in order to be able to make a pair of sub-units of a smoking article.

The machine 100 also comprises a feed unit 102 configured to store and convey the continuous web 3, in particular through the various production steps necessary for producing the connecting strips 2.

The continuous web 3 may be conveyed both in such a way that the connecting strips just separated from the continuous web 3 are placed side by side, or in such a way that the connecting strips 2 just separated from the continuous web 3 are lined up with each other.

The machine 100 also comprises a weakening unit 200 (shown only schematically in Figure 2) to form at least one weakened zone 20 on the continuous web 3, arranged downstream of the feed unit 102. The weakening unit 200 - in turn - may comprise embossing means (e.g. embossing rollers) and/or laser means (e.g. a laser source) and/or creasing means (e.g. punch) not shown in detail.

In the embodiment (not shown) that involves feeding the continuous web 3 with the weakened zones 20 already present thereon, the machine 100 does not include the feeding unit, but there is a weakening station upstream of the machine 100 intended to form the aforesaid weakened zones 20 on the continuous web 3. It remains clear that the aforesaid weakening station could also be arranged in a different system or - in any case - in a remote position with respect to that of the machine 100.

The machine 100 therefore comprises a gumming device 103 associated with the feeding unit 102 and arranged along a conveying path of the continuous web 3, preferably downstream of the weakening unit 200.

The gumming device 103 is configured to apply an adhesive substance on at least one first portion, preferably a central portion, of the continuous web.

Preferably, this central portion is intended to form the first portion 2a of respective connecting strips 2.

The gumming device 103 may be further configured to also apply the adhesive substance on additional portions of the continuous web, in particular on portions intended to form the second portions 2b of the connecting strips 2.

The machine 100, therefore, comprises a pair of cutting drums 104 which cooperate with each other to separate a succession of connecting strips 2 from a front end of the continuous web 3.

In particular, the pair of cutting drums 104 comprises a first drum 104a, which has a succession of cutting blades on its surface configured to engage the continuous web 3, determining the separation of the succession of connecting strips 2.

The pair of cutting drums 104 also comprises a second drum 104b designed to convey the continuous web 3 until it engages the cutting blades of the first drum 104a.

The second drum 104b is also configured to radially space apart the individual connecting strips 2 once they have been separated from the continuous web 3, in this way it is possible to facilitate their subsequent application to the respective double-length tubular wrappers 11.

The machine 100 therefore comprises an applicator drum 105 configured to receive a succession of double-length tubular wrappers 11 from the conveyor drum 101 and to transport them to an application station.

In the application station, each double-length tubular segment 11 receives a corresponding connecting strip 2 from one drum of the pair of cutting drums 104, so that the first portion 2a of each connecting strip 2 is applied between opposite ends of a respective double-length tubular segment 11, and that this connecting strip has a pair of second portions 2b axially projecting with respect to the ends of the double-length tubular segment 11.

The machine 100 also comprises folding means 106 located at or downstream of said applicator drum 105 to fold each second portion 2b of the connecting strips 2 at the relative weakened zone 20 in such a way as to make a closing wall which at least partly closes respective ends of the double-length tubular segment 11.

The folding means 106 may, for example, comprise guides suitable for engaging the second portions 2b of the connecting strips 2 guiding them in rotation along a path that approaches the respective end openings of the double-length tubular segment 11, thus deforming them by folding them transversely to the first portion 2, at the relative weakened zone 20.

In accordance with a particular embodiment, the folding means 106 comprise a fixed folding device associated with the applicator drum 105 or applied at a drum arranged immediately downstream of the applicator drum 105. Alternatively, in accordance with a different embodiment, the folding means 106 comprise a pre-folding station and a folding station.

The pre-folding station is arranged at or immediately downstream of a transfer zone of the connecting strips 2 from the cutting drums 104 to the applicator drum 105.

In particular, the pre-folding station comprises a movable folding device.

This movable folding device may be mounted on a suitable drum arranged at the transfer zone of the connecting strips 2.

Still in accordance with this embodiment, the folding station comprises a fixed folding device associated with the applicator drum 105 or applied on a drum arranged immediately downstream of said applicator drum 105.

Preferably, the machine 100 also comprises a rolling bed associated with the applicator drum 105 to carry out the rolling of each assembly comprising a doublelength tubular segment 11 and a relative connecting strip 2 applied thereto.

Preferably, the rolling bed is arranged upstream of the folding means 106, in such a way that the rolling process allows strengthening of the adhesion of the connecting strip to the outer wall of the double-length tubular segment 11 before the folding operation is performed of the second portions 2b.

In fact, the greater the width of the connecting strips 2, the smaller the contact portion present between it and the double-length tubular segment 11 with respect to their overall surface.

Thanks to the presence of the rolling bed it is therefore possible to carry out the folding of the second portions 2b of the connecting strips 2 only after their first portions 2a have been made to adhere completely and integrally to the outer wall of the respective double-length tubular segment 11.

In accordance with a particular aspect of the present invention, the machine 100 further comprises a cutting device 107 arranged downstream of the folding means 106, and configured to cut the double-length tubular segment 11 along its mid-plane "M", obtaining two sub-units of the tobacco industry abutting at this midplane "M".

Said cutting device 107 may be made, for example, by means of a cutting blade which intercepts the double-length tubular wrappers 11 in their advancement path leaving the folding means 106, preferably when these double-length tubular wrappers 11 have been transferred from the drum applicator 105 to an additional drum 108. The additional drum 108 is specially configured to cooperate with the cutting device 107 to operate a correct separation of the double-length tubular segment 11 into two mutually abutting sub-units of a smoking article.

Advantageously, the present invention achieves the proposed objects by overcoming the drawbacks of the prior art by providing the user with a machine for producing sub-units of smoking articles that allows producing a succession of subunits equipped with a closing wall suitable for promoting the containment of the filling material of the smoking article, especially once the finished product has been assembled.

The present invention also relates to a sub-unit of a smoking article preferably obtained by means of the method and/or the machine according to the invention described above.

The sub-unit comprises: a tubular segment 1 of the tobacco industry which internally has a through-duct terminating in end openings of the tubular segment 1; and a connecting strip 2 applied longitudinally to the tubular segment 1, having a first portion 2a, a second portion 2b and at least one weakened zone 20 between the first portion 2a and the second portion 2b (which may also occupy, at least partially, the first portion 2a and/or the second portion 2b of the connecting strip 2, as illustrated in Figures ID, IE).

The first portion 2a of the connecting strip 2 is superposed on the outer surface of the tubular segment 1, and has a transverse dimension such as to cover a first angular portion of the outer surface of the tubular segment 1, leaving uncovered a second angular portion of the outer surface of the tubular segment 1. The second portion 2b of the connecting strip 2 defines an extension of the first portion 2a, and is folded transversely to the first portion 2a at the weakened zone 20, to form a closing wall which at least partly closes the at least one end opening of the tubular segment 1.

Advantageously, the sub-unit according to the present invention ensures the containment of the filling material of the smoking article, especially once the finished product has been assembled, and is easy to manufacture.