EP3728049A1

EP3728049A1 - Method to make hermetic wrappers and corresponding machine

Info

Publication number: EP3728049A1
Application number: EP18811074.6A
Authority: EP
Inventors: Fiorenzo Draghetti
Original assignee: IMA Industria Macchine Automatiche SpA
Current assignee: IMA Industria Macchine Automatiche SpA
Priority date: 2017-12-21
Filing date: 2018-10-29
Publication date: 2020-10-28
Also published as: WO2019123497A1

Abstract

A method and a machine are described, usable in particular in the field of packaging smoking articles to make a hermetic wrapper, which provide a first conveyor configured to form an assembled structure comprising an organized group of smoking articles and a reinforcement insert, a second conveyor configured to form a pre-wrapper in which a wrapper sheet is folded around a structured assembly, and a welding unit configured to seal the pre-wrapper so as to obtain the hermetic wrapper.

Description

“METHOD TO MAKE HERMETIC WRAPPERS AND CORRESPONDING MACHINE”

FIELD OF THE INVENTION

The present invention concerns a method to make a hermetic wrapper and a packaging machine which implements the method. In particular, the method and the machine can be used in the field of packets for smoking articles, and are suitable - for example - to make a hermetic gusset-type wrapper with welded lateral fins.

BACKGROUND OF THE INVENTION

Smoking articles are traditionally packed in rigid or semi-rigid packets, inside which the smoking articles are wrapped in an inner wrapper, generally made of tinfoil.

Normally, a reinforcement insert is present in cooperation with the inner wrapper.

This form of wrapper represents a compromise solution between production costs and the need to maintain the aromatic characteristics of the tobacco present in smoking articles unaltered.

In order to better preserve the qualities of smoking articles, there is a growing need to make a sealed inner wrapper, that is, obtained with a sheet of material that does not allow air to pass, suitably sealed around the group of smoking articles contained therein.

The present invention is connected to technical solutions and operational methods that have been the subject of patent protection which covers solutions that, structurally and functionally, are not able to define a result suitable for the desired purpose, and in the required terms.

In particular, the international patent application WO-A-2016/166141, by the same Applicant, concerns a packaging machine able to produce a hermetic wrapper around a group of smoking articles.

The packaging machine described in this document comprises a first wheel provided with a plurality of pockets, each intended to contain a group of smoking articles. The first wheel has the double function of disposing a wrapper around the group of articles, after having associated a reinforcement insert with them. Downstream of the first wheel, the packaging machine comprises a second wheel comprising a plurality of gripping members each configured to receive the wrapper which has been partly formed in the first wheel and to perform a welding step thereon, to weld a pair of flaps so as to form a first fin defining the bottom of the wrapper, and a subsequent folding step which folds the fin against one of the walls of the wrapper.

The packaging machine described in WO-A-2016/166141 also comprises a plurality of folding and welding stations disposed downstream of the second wheel to form and fold the lateral fins and weld them appropriately, to close the casing and obtain a hermetically closed casing.

One disadvantage of this packaging machine is that it is very complex from a structural point of view.

Another disadvantage of this packaging machine is that, in order to function correctly, it requires great precision in production. In fact, the machine requires accurate initial setting operations before each different batch of packets of smoking articles is packed.

In general, one technical problem that affects packaging machines known in the state of the art is to guarantee that the operations which are carried out gradually on the external wrapper are organized in such a way that the parts of the wrapper concerned, such as flaps or fins, are kept in the desired folded position, preventing them from reopening in an undesired way, until the next operation.

In particular, one complexity of known machines concerns keeping the lateral flaps or fins folded in a desired manner, preventing them from reopening when they are supplied to the welding unit which welds the lateral fins.

Another technical problem of packaging machines known in the state of the art is, therefore, that their structure is very bulky and their functioning is complicated to control and manage.

There is therefore a need to perfect a method to make hermetic wrappers and a corresponding machine which can overcome at least one of the disadvantages of the state of the art.

In particular, one purpose of the present invention is to provide a packaging machine, as well as the corresponding and connected operating methods to sequentially and continuously obtain, first a pre-wrapper and subsequently a hermetic wrapper which wraps the group of smoking articles.

Another purpose of the present invention is to provide a packaging machine, and to perfect the corresponding method, having an optimized layout that allows to simplify the functioning of the machine.

Another purpose of the present invention is to provide a packaging machine which has a disposition of the working stations, in particular at least the folding and welding stations, which makes the machine and its functioning simpler.

The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.

SUMMARY OF THE INVENTION

The present invention is set forth and characterized in the independent claims, while the dependent claims describe other characteristics of the invention or variants to the main inventive idea.

Embodiments of the present invention concern a method to make a hermetic wrapper and to the packaging machine which makes it.

The hermetic wrapper contains inside a structured assembly comprising a reinforcement insert associated with an organized group of smoking articles. The hermetic wrapper is correctly and exhaustively sealed, and aesthetically pleasing, and possibly, on each occasion, is made accessible inside it.

The structured assembly is obtained by using a reinforcement insert with which the smoking articles are associated layer by layer or as a whole.

The reinforcement insert is obtained from a preformed cardboard sheet, folded in such a way as to define a base wall and two lateral walls which extend parallel to each other from the base wall, and which define, during use, the lateral walls that contain the organized group of smoking articles, as well as at least one support and abutment edge.

The hermetic wrapper is obtained from a preformed sheet of heat-weldable material that is first pre-positioned shaped as a U with respect to the structured assembly and then suitably folded, defining a bottom fin and lateral fins folded like a gusset, to completely wrap the structured assembly and finally to be stably sealed by welding. The hermetic wrapper can provide inside its perimeter, and in a suitable position, an aperture temporarily closed by means of a label, or a tongue, possibly of an adhesive type, and reusable.

According to some aspects of the present invention, a method and a machine for making a hermetic wrapper are provided in which the structured assembly and the U-shaped wrapper sheet that wraps it along a curved segment of a working path that develops between an entrance station and an exit, where a folding station is disposed, and is served by a suitable transfer conveyor, to perform, in a first working station of the intermediate transfer conveyor between the entrance station and the exit of the working path, folding and welding of the bottom fin and, subsequently downstream of the first folding station along the curved segment of the working path, also the folds to make the lateral fins folded as a gusset, which overall allow to form a pre-wrapper that is a precursor of the hermetic wrapper.

According to one aspect of the present invention, all the operations to fold the flaps of the wrapper sheet needed to make the lateral fins folded as a gusset are made in a single folding station comprised in the transfer conveyor, disposed at the exit of the working path, and to which the structured assembly and the wrapper sheet that wraps it are fed along the curved segment of the working path.

Moreover, the present invention advantageously provides that, after having made the folds to make the lateral fins folded like a gusset in the corresponding folding station at the exit from the working path, the pre-wrapper is moved linearly at exit from the working path, keeping all the lateral fins of the pre wrapper folded in the desired position and defined in the folding station, toward a welding station downstream of the transfer conveyor, where the welding of the lateral fins folded like a gusset is carried out.

In one embodiment, the linear path along which the pre -wrapper is moved at exit from the working path, from the corresponding folding station toward the welding station downstream, is, or comprises, a rectilinear segment.

In one embodiment, the curved segment of the working path is an arc of a circumference and the transfer conveyor is a transfer wheel or carousel which transports the structured assembly and the wrapper sheet that wraps it along a circular path which defines the working path. According to some embodiments, the linear path develops along a radial directrix of the circumference defining the working path, so that the pre-wrapper is moved from the folding station to the welding station exiting radially from the curved segment of the working path.

According to one embodiment, linear feed means are provided disposed at least between the folding station and the welding station to feed the pre-wrapper along the linear path.

In one embodiment, the linear feed means are adjacent and contiguous to the folding station.

Advantageously, but not restrictively, in accordance with possible embodiments, the operation to weld the lateral fins folded like a gusset is carried out in the welding station downstream of the transfer conveyor along a linear welding path, in particular rectilinear. In particular, the welding station, for this purpose, can be provided with a linear conveyor configured to feed the pre- wrapper along the linear welding path.

According to some embodiments, the welding station is also provided with a welding unit which comprises one or more welding devices configured to heat the opposite fins or lateral flaps that project from the lateral walls of the pre wrapper and which have been suitably folded in the folding station disposed at the exit of the transfer conveyor.

In some embodiments, in the first working station it is provided to reciprocally join the free flaps of the wrapper sheet to obtain a semi-finished assembly in which the wrapper sheet continuously wraps the structured assembly, in particular in a longitudinal direction of development of the latter. In other words, downstream of the first working station, the wrapper sheet is closed in a ring around the structured assembly.

According to some embodiments, another forming conveyor is also provided which is disposed upstream of the transfer conveyor and is configured to form the structured assembly and to associate a respective wrapper sheet therewith.

In one embodiment, this other formation conveyor is a wheel or a formation carousel disposed so that its axis of rotation is substantially orthogonal to the axis of rotation of the transfer conveyor, that is, disposed lying on a plane orthogonal to the plane of the transfer conveyor. In one embodiment, between the folding station and the welding station an intermediate guide station is provided, configured to guide the pre-wrapper toward the welding unit, keeping the fins folded in the desired position and defined by the folding station disposed at the exit of the transfer conveyor, and to better define the lateral longitudinal folds from which the lateral fins or flaps extend. The intermediate guide station is advantageously configured to cooperate both with the linear feed means and also with the linear conveyor of the welding station.

Thanks to the embodiments described here, a packaging machine with an optimized layout which allows to simplify the method to make a hermetic wrapper is advantageously made available.

Another advantage of the method according to the embodiments described here is that it allows to simplify the operations of handling the pre- wrapper and the hermetic wrapper obtained from it.

Advantageously, the method and the machine to make a hermetic wrapper according to the embodiments described here allow to move the objects being worked, that is, the structured assembly first, then the intermediate and semi- finished assembly, and finally the pre-wrapper and the hermetic wrapper, with great reliability, holding them firmly in the successive different positions provided in order to be subjected to different workings. In particular, it is possible to keep the lateral fins folded in a desired manner during the passage from the folding station of the transfer conveyor to the welding station downstream, preventing them from reopening when they are supplied to the welding station where it is provided that the lateral fins are welded.

These advantages allow to reduce working waste and cycle times since, thanks to the optimized layout, the packaging machine and the method according to the embodiments described here can operate at higher speeds compared to similar machines and methods known in the state of the art.

These and other aspects, characteristics and advantages of the present disclosure will be better understood with reference to the following description, drawings and attached claims. The drawings, which are integrated and form part of the present description, show some forms of embodiment of the present invention, and together with the description, are intended to describe the principles of the disclosure.

The various aspects and characteristics described in the present description can be applied individually where possible. These individual aspects, for example aspects and characteristics described in the attached dependent claims, can be the object of divisional applications.

It is understood that any aspect or characteristic that is discovered, during the patenting method, to be already known, shall not be claimed and shall be the object of a disclaimer.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other characteristics of the present invention will become apparent from the following description of some embodiments, given as a non-restrictive example with reference to the attached drawings wherein:

- fig. 1 is a schematic perspective view of a packaging machine in accordance with embodiments of the present invention;

- fig. 2 is a partial schematic perspective view of an enlarged detail of an embodiment of the packaging machine according to the invention;

- fig. 3 is a partial schematic plan view, of the detailed view in fig. 2;

- fig. 4a is a schematic three-dimensional view of a wrapper;

- fig. 4b is a three-dimensional view of a structured assembly given by the combination of a reinforcement insert wrapped partly around an organized group of smoking articles;

- figs. 5a-5g schematically show the steps of folding the wrapper sheet around the assembly in fig. 4b.

To facilitate comprehension, the same reference numbers have been used, where possible, to identify identical common elements in the drawings. It is understood that elements and characteristics of one embodiment can conveniently be incorporated into other embodiments without further clarifications.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

We will now refer in detail to the various embodiments of the present invention, of which one or more examples are shown in the attached drawings. Each example is supplied by way of illustration of the invention and shall not be understood as a limitation thereof. For example, the characteristics shown or described insomuch as they are part of one embodiment can be adopted on, or in association with, other embodiments to produce another embodiment. It is understood that the present invention shall include all such modifications and variants.

Embodiments described here with reference to fig. 1 concern a packaging machine 10 suitable to make a hermetic wrapper 12 for smoking articles.

The hermetic wrapper 12 is formed starting from an appropriately shaped and pre-cut wrapper sheet 112.

In one embodiment, the wrapper sheet 112 can be made of a suitable material, selected from a group consisting of: paper, cardboard, polymeric material, aluminum, tinfoil or metallized paper.

The hermetic wrapper 12 comprises inside it an organized group of smoking articles 14 and a reinforcement insert 16.

For a better understanding of the following detailed description of the method and machine according to the present invention, with particular reference to fig. 4a, the hermetic wrapper 12 which can be obtained according to the method by means of the machine is briefly described here. Within the field of the present description, the term“structured assembly” indicates the association between the reinforcement insert 16 and the organized group of smoking articles 14, before the wrapper sheet 112 is associated with them. The structured assembly, visible in particular in fig. 4b, is indicated as a whole with the reference number 11.

The reinforcement insert 16 has a base wall 16a and two lateral walls, or lateral fins 16b in continuity with the base wall 16a. The latter, together with the lateral walls 16b, are disposed reciprocally so as to wrap the smoking articles 14 on three sides.

It is also possible to identify two walls, a head wall 14b and a bottom wall 14c, which are defined respectively by the opposite ends of the smoking articles 14, and a second base wall l4a which is substantially tangent to the row of smoking articles 14 most distant from the base wall 16a.

The hermetic wrapper 12 comprises a bigger front lateral wall 18, positioned on the base wall l6a, a bigger rear lateral wall 19, positioned on the second base wall l4a, and smaller lateral walls defined by four longitudinal lateral flaps 20 which overlap the lateral walls 16b in pairs.

The hermetic wrapper 12 also comprises an upper wall 21 and a lower wall 22 which respectively overlap the head wall 14b and the bottom wall 14c, and at the same time hermetically connect with each other.

The packaging machine 10 comprises a first wheel 39 provided with a plurality of forming pockets 40.

In one embodiment, the first wheel 39 is moved in a stepwise movement.

Along the circumference of the first wheel 39 a formation path F defined by specific working stations is defined.

In the example shown, the first wheel 39 is configured to rotate on a substantially vertical plane around a horizontal axis of rotation X along the formation path F, with every step taking a pocket 40 in correspondence with a specific working station.

Each forming pocket 40 comprises a chamber 50, shaped substantially like a parallelepiped, and configured to accommodate an organized group of smoking articles 14.

According to some embodiments, a first insert introduction station 35 is provided, in which a reinforcement insert 16 is introduced into the chamber 50.

The insert introduction station 35 comprises a pickup member 48 configured to pick up the reinforcement insert 16 from a dedicated store (not shown) and deliver it to an introduction member 46 which is intended to introduce the reinforcement insert 16 into the chamber 50.

According to some embodiments, it can be provided that the reinforcement insert 16 is already shaped like a“U”, or other suitable or appropriate shape, ready to be introduced into the chamber 50.

According to a variant, it can be provided that the reinforcement insert 16 is fed to the insert introduction station 35 in its flat conformation, and subsequently shaped, for example like a“U”, by means of a deformation device 47. The latter is configured to fold the two opposite lateral walls 16b with respect to the base wall 16a so as to define the desired shape, for example a“U” shape.

Downstream of the insert introduction station 35, along the formation path F, at least one introduction station 36 for the smoking articles is also provided, in which the organized group of smoking articles 14 is introduced into the chamber 50 into which the reinforcement insert 16 was previously introduced.

The introduction station 36 comprises at least one thrust member 49 which thrusts the smoking articles 14 into the pocket 40.

Depending on the production rate required of the machine 10, there can be one or more introduction stations 36. By way of example, fig. 1 shows three introduction stations 36, in each of which an organized group of smoking articles 14 can be introduced in the chamber 50 of a respective pocket 40.

After the introduction station 36, along the formation path F, a feed station 37 is provided to feed the wrapper sheet in which the wrapper sheet 112, already pre-cut and prepared according to requirements, is fed.

The wrapper sheet 112 is applied by a feed device 45 on the external side of the chamber 50.

According to possible embodiments, the feed device 45 can be U-shaped, with two arms, 45a, 45b that extend parallel and opposite each other, at a distance consistent with the height of the external walls of the chamber 50.

The feed device 45 slides with the arms 45 a, 45b on the external walls of the chamber 50 and in this way it moves the wrapper sheet 112, present therein, giving it its“U” shape, with the bottom positioned overlapping on one of either the head wall 14b or bottom wall 14c.

Downstream of the feed station 37 of the wrapper sheet there is also an exit station 38, in which the assembly formed by the group of smoking articles 14 and the reinforcement insert 16 is expelled from the chamber 50 of the respective forming pocket 40.

In accordance with some embodiments, the exit station 38 can comprise a thrust device 68 suitable to cooperate with the pocket 40 to expel the assembly from the respective chamber 50 to subsequent working stations.

In the exit station 38, during the expulsion movement of the assembly, the latter is directly associated with the wrapper sheet 112. In fact, the thrust device 68 thrusts the smoking articles 14 and the reinforcement insert 16 out of the chamber 50, against the U-shaped wrapper sheet 112 so as to draw the latter, which moves integrally thereto away from the exit station 38.

In this step, the wrapper sheet 112 is associated with and positioned above the base walls 14a, 16a and the head wall 14b, defining an intermediate assembly 1 la, visible in fig. 5a.

The packaging machine 10 comprises a second wheel 71 provided with a plurality of gripping members 70 on its periphery.

In one embodiment, the second wheel 71 is configured to rotate stepwise around a vertical axis of rotation Y so as to define a working path L which develops along a circumference C.

The working path L, in the embodiment shown by way of example in fig. 1, cooperates with the formation path F in such a way as to align the exit station 38 from the first wheel 39 to a corresponding entrance station 41 in the second wheel 71.

Along the working path L the intermediate assembly 11a is worked, which consists of the organized group of smoking articles 14, the reinforcement insert 16 and the wrapper sheet 112 wrapped around them.

In the entrance station 41, the intermediate assembly 11a is delivered to a respective gripping member 70.

In one embodiment, the intermediate assembly 11a reaches the gripping member 70 thanks to the action of the thrust device 68, directly after having moved away from the chamber 50.

In one embodiment, the thrust device 68 is disposed substantially aligned with the chamber 50 of the pocket 40 disposed in the exit station 38 and with the gripping member 70 disposed in the entrance station 41 so that the displacement of the intermediate assembly 1 la from the first wheel 39 to the second wheel 71 is substantially linear.

According to other embodiments, between the exit station 38 and the entrance station 41 of the intermediate assembly 1 la, alignment and guide devices 69 can be advantageously present, configured to keep the intermediate assembly 11a aligned during its introduction into the gripping member 70.

The second wheel 71, by rotating, takes the gripping member 70 from the entrance station 41 to a first working station 42, and subsequently to a folding station 44, which defines an exit station of the pre- wrapper 12a from the second wheel 71.

According to some embodiments, the gripping member 70 has a fixed base plane 80 and an upper plane 81 elastically pressed over the intermediate assembly 1 la, so as to hold the components comprised therein in position.

In the first working station 42 the lower flap 24 and the upper flap 25 of the wrapper sheet 112, that is, its free flaps, are associated and welded to each other as shown in fig. 5b, to form a transverse edge 28 which defines a bottom fin, so as to obtain a semi-finished assembly 1 lb.

According to some embodiments, the transverse edge 28 is disposed so as to be coplanar with the bigger lateral wall 18 of the semi-finished assembly l ib, constituting an extension thereof.

In accordance with some embodiments, the first working station 42 is provided with a pair of welding devices 74, 75, that is, an upper welding device 74 and a lower welding device 75, which act on the intermediate assembly 11a retained by the gripping member 70.

The upper welding device 74, in the case shown, can advantageously be fixed, while the lower welding device 75 can be mobile between a position of non- interference with the wrapper sheet 112 and a position in which it interferes with the lower flap 25, holding it near the bottom wall 14c and at the same time bringing it closer to the upper flap 24 and the upper welding device 74 so as to make the transverse edge 28 and obtain the semi-finished assembly l ib.

In the folding station 44 all the folds of the wrapper sheet 112 are completed in order to make the lateral fins 29 folded in a gusset, so as to obtain a pre-wrapper 12a starting from the semi-finished assembly l ib; the pre-wrapper 12a being ready to undergo subsequent sealing operations.

According to some embodiments, between the first working station 42 and the folding station 44, a cam 77 can be provided, configured to interfere with the already welded transverse edge 28 of the semi-finished assembly l ib during its transfer to the folding station. 44 and raise it to the desired position.

A folding device is provided in the folding station 44, comprising a plurality of folding members 92, 94, 96, 98, organized in specialized pairs, each pair being suitable to perform a specific folding of the wrapper sheet 112 so as to obtain the pre-wrapper 12a.

The folding device comprises a pair of front folders 92 and a pair of rear folders 94, configured respectively to fold the portions of the lateral flaps 27, 26 projecting laterally in a transverse direction from the semi-finished assembly 1 lb, making them adhere to the lateral walls 16b of the reinforcement insert 16.

In particular, the front folders 92 act on the lateral flaps 27, in the direction indicated by the arrow Dl in fig. 5c, while the rear folders 94 act on the lateral flaps 26 in the direction indicated by the arrow D2 in fig. 5c.

Advantageously, according to a possible solution, the folding device also comprises a pair of upper folders 96, configured to act as indicated by the arrows D3 in fig. 5c in order to fold the welded transverse edge 28 by about 180°, taking it into contact with the bigger lateral wall 18.

The folding device also comprises two pairs of lateral folders 98, each consisting of an upper lateral folder 98a and a lower lateral folder 98b, configured to act against the longitudinal lateral edges 20 of the wrapper sheet 112 which protrude beyond the lateral walls 16b, and obtain the lateral flaps or fins 29.

The lateral folders 98 subsequently intervene with respect to the front and rear folders 92, 94 in the direction indicated by the arrows D4 and confer a V-shaped section on the longitudinal lateral edges 20, recessed in the median zone until it contacts the lateral walls 16b, as visible in figs. 5d and 5e.

According to some embodiments, the upper and lower lateral folders 98a and 98b are disposed inclined and/or are suitably shaped in an angled manner.

According to some embodiments, the front folders 92 and/or the rear folders 94 advantageously have a substantially triangular shape in the zone that assists the folding.

In one embodiment, in correspondence with the definitive folding station 44, it is provided to extract the pre- wrapper 12a thus formed from the respective gripping member 70, for example by means of an extractor member, not shown.

From the definitive folding station 44, the pre-wrapper 12a then passes to a welding station 115, where a welding unit 34 is provided which stabilizes the connection of the lateral fins or flaps 29, possibly making the transverse edge 28 also integral with them, so as to obtain the hermetic wrapper 12.

In a preferred embodiment, from the folding station 44 to the welding unit 34, the pre -wrapper 12a follows a path P which is substantially linear.

The packaging machine 10 comprises a conveyor belt 130 disposed between the second wheel 71 and the welding unit 34 and configured to take the pre- wrapper 12a toward the latter.

Between the folding station 44 and the welding unit 34 there can be an intermediate guide station 43 which keeps the lateral fins 29 folded in the desired position and defined by the folding station 44 and which also allows to better define the longitudinal folds that define the lateral fins 29.

The intermediate guide station 43 comprises guide members 114 configured to bring the lateral fins 29 close to each other and also to position them adhering to the structured assembly 11.

Downstream of the intermediate guide station 43, the pre-formed wrapper 12a has the lateral fins 29 projecting substantially in an orthogonal direction from the lateral walls 16b, as shown in figs. 5f and 5g.

According to some embodiments, the guide members 114 can comprise a slit, possibly provided in the entrance direction with a flared or spread portion, able to define a lead-in to facilitate the introduction of the lateral fins 29 of the pre wrapper 12a.

ln accordance with possible solutions, the intermediate guide station 43 can comprise heating devices, not shown, suitable to heat to a desired temperature the lateral fins 29 of the pre- wrapper l2a associated with each other, so as to facilitate the subsequent welding thereof.

In this version, the conveyor belt 130 connects the folding station 44 with the intermediate guide station 43, which is interposed between the folding station 44 and the welding station 115, and the welding unit 34.

In one embodiment, the conveyor belt 130 defines linear transport means which develop starting from the folding station 44, pass through the intermediate guide station 43 and the welding station 115 so as to cooperate with the welding unit 34 to define a linear welding path.

According to some embodiments, the welding unit 34 comprises at least one welding device 120 for each side of the pre-wrapper l2a.

Each welding device 120 comprises a pressure welding member 121 and a regulated counter-pressure welding member 122.

According to some embodiments, the pressure welding member 121 and the counter-pressure welding member 122 have sizes consistent with the length and width of the lateral fins 29 to be welded.

To increase the production capacity of the machine 10 multiple identical stations can be provided, that is, the functions of one station can be diluted in several stations.

The number of welding stations 115 is not determined only by the production regime, but is also determined by the welding time-cycle which is intended to be set and/or by the type of wrapper sheet 112 and therefore its welding requirements.

It is clear that modifications and/or additions of parts can be made to the method and machine as described heretofore, without departing from the field and scope of the present invention.

It is also clear that, although the present invention has been described with reference to some specific examples, a person of skill in the art shall certainly be able to achieve many other equivalent forms of method or machine, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.

In the following claims, the sole purpose of the references in brackets is to facilitate reading: they must not be considered as restrictive factors with regard to the field of protection claimed in the specific claims.

Claims

1. Method to make a hermetic wrapper (12) with folded welded lateral fins of the gusset type, comprising a wrapper sheet (112) hermetically wrapped around a structured assembly (11) comprising an organized group of smoking articles (14) and a reinforcement insert (16), said method comprising the steps of:

- associating said wrapper sheet (112) with said structured assembly (11) so that said wrapper sheet (112) is U-shaped to partly wrap said structured assembly (11),

- working said structured assembly (11) and said wrapper sheet (112) along a curved segment of a working path (L) that develops between an entrance station (41) and an exit, where a folding station (44) is disposed, and is served by a suitable transfer conveyor (71),

- folding and welding a bottom fin (28) in a first working station (42) of said transfer conveyor (71) that is disposed intermediate between said entrance station (41) and said exit of said working path (L),

- performing all the folding operations of flaps (20, 26, 27, 28) of said wrapper sheet (112), needed to make folded lateral fins (29) of the gusset type and to obtain a pre- wrapper (12a), precursor of said hermetic wrapper (12), in a single folding station (44) comprised in said transfer conveyor (71) disposed at the exit of said working path (L) and downstream of said first working station (42) along said curved segment of said working path (L),

- moving said pre- wrapper (12a) linearly exiting from said working path (L), keeping said lateral fins (29) of said pre- wrapper (12a) folded in the desired and defined position in said folding station (44), toward a welding station (115) disposed downstream of said transfer conveyor (71),

- welding said lateral fins (29) in said welding station (115) to obtain said hermetic wrapper (12).

2. Method as in claim 1, characterized in that said curved segment of said working path (L) is an arc of a circumference (C) and said working path (L) is a circular path defined by said circumference (C).

3. Method as in claim 1 or 2, characterized in that said moving of said pre wrapper (12a) exiting from said working path (L), from said folding station (44) toward said welding station (115), provides to move said pre- wrapper (12a) along a rectilinear segment.

4. Method as in claim 2 or 3, when dependent on claim 2, characterized in that said moving of said pre-wrapper (12a) provides to move it along a radial directrix of said circumference (C), so that said pre- wrapper (12a) is moved from said folding station (44) to said welding station (115) exiting radially from the curved segment of said working path (L).

5. Method as in any claim hereinbefore, characterized in that said welding of said lateral fins (29) in said welding station (115) provides that the welding operation is performed along a linear welding path, in particular rectilinear.

6. Method as in any claim hereinbefore, characterized in that it is provided to guide said pre-wrapper (12) between said folding station (44) and said welding station (115) by means of an intermediate guide station (43) configured to guide said pre-wrapper (12a) toward said welding station (115), keeping said lateral fins (29) folded in the desired and defined position by said folding station (44) disposed at the exit of said transfer conveyor (71), and to better define the lateral longitudinal folds from which said lateral fins (29) extend.

7. Packaging machine to make a hermetic wrapper (12) of the gusset type comprising a wrapper paper (112) wrapped hermetically around a structured assembly (11) comprising an organized group of smoking articles (14) and a reinforcement insert (16), comprising:

- a formation conveyor (39) configured to form said structured assembly (11) and to associate with it said wrapper sheet (112) so as to shape said wrapper sheet (112) in a U-shape around said structured assembly (11),

- a transfer conveyor (71) disposed downstream of said formation conveyor (39) and configured to allow said structured assembly (11) and said wrapper sheet

(112) to be processed along a curved segment of a working path (L) that develops between an entrance (41) and an exit (44),

- a first working station (42) configured to fold and weld a bottom fin (28),

- a single folding station (44) configured to perform all the folding operations of flaps (20, 26, 27, 28) of said wrapper sheet (112) so as to obtain folded lateral fins (29) of the gusset type and obtain a pre-wrapper (12a), precursor of said hermetic wrapper (12), said folding station (44) being disposed at the exit of said working path (L) and downstream of said first working station (42) along said curved segment of said working path (L),

- linear transport means (130) configured to move said pre- wrapper (l2a) linearly exiting from said working path (L), keeping said lateral fins (29) of said pre- wrapper (12a) folded in the desired position and defined in said folding station (44), toward a welding station (115) of said machine disposed downstream of said transfer conveyor (71),

- a welding unit (34) configured to weld said lateral fins (29) in said welding station (115) so as to obtain said hermetic wrapper (12).

8. Machine as in claim 7, characterized in that said second conveyor (71) is configured as a wheel or a carousel that transports said structured assembly (11) and said wrapper sheet (112) that wraps it along a circular path that defines said working path (L), and in that said first working station (42) and said folding station (44) are disposed in succession at the periphery of said transfer conveyor (71).

9. Machine as in claim 7 or 8, characterized in that said linear transport means

(130) comprise a conveyor belt and are disposed adjacent to said transfer conveyor (71), in particular in correspondence with said folding station (44) to receive said pre-wrapper (12a) from said folding station (44) and take it toward said welding station (115).

10. Machine as in any of the claims from 7 to 9, characterized in that said linear transport means (130) comprise at least a segment that extends along a radial directrix of said circumference (C) and pass through both an intermediate guide station (43), interposed between said folding station (44) and said welding station (115), and also said welding station (115) so as to transport said pre- wrapper (12a) during the welding operation along a linear welding path.