ITUA20164192A1 - Wrapping method and packaging machine for folding a heat-sealable wrapping sheet around a group of smoking articles. - Google Patents

Description

Title

Wrapping method and wrapping machine to fold a sheet of heat-sealable wrapping around

a group of smoking items.

"Wrapping method and packing machine for folding a sheet of heat-sealable wrapping around a group of smoking items."

TECHNIQUE SECTOR

The present invention relates to a wrapping method and a packaging machine for folding a sheet of heat-sealable wrapping around a group of smoking articles.

The present invention finds advantageous application to the folding of a sheet of heat-sealable wrapping around a parallelepiped group of cigarettes to make a sealed wrapping, to which the following discussion will explicitly refer without losing generality.

ANTERIOR ART

For several years, rigid packets of cigarettes of the type described in US patent 4300676A1 have been proposed on the market, in which the internal wrapping is waterproof and consists of a sheet of waterproof and heat-sealable material having a cigarette extraction opening. , which is closed by a reusable closure label.

Patent application WO2010136869A1 describes a wrapping method for making a sealed wrapping, according to which the steps of: feeding the group of cigarettes and the wrapping sheet into a pocket of a wrapping wheel are provided in such a way that the wrapping sheet is folded into a "U" inside the pocket and has an external flap that protrudes from the pocket and an internal flap that rests on a side wall of the group of cigarettes; folding the inner flap by 90 ° with respect to the side wall of the group of cigarettes in such a way as to arrange the inner flap perpendicular to the side wall itself; fold the outer flap inside the pocket into an "L" shape, against the side wall of the group of cigarettes and against the inner flap placed perpendicular to the side wall so as to overlap the outer flap and the inner flap on top of each other, giving the sheet of wrapping a tubular form; and heat-seal the outer flap and the inner flap together. Patent application WO2010136869A1 uses a wrapping wheel provided with a plurality of pockets, each of which comprises a bottom wall and two side walls parallel and opposite to each other; a side wall of each pocket has a reduced size with respect to the opposite side wall so as to leave the internal flap of the wrapping sheet uncovered and ends with a transversal support element, which is arranged perpendicular to the side wall and is provided with suction in so as to attract and hold the internal flap of the wrapping sheet by suction. Each transversal support element performs the contrast function both during the folding of the external flap against the internal flap, and during the subsequent heat-sealing of the external flap to the internal flap.

The fact that the contrast used during heat sealing (i.e. the transverse support element) is mounted on the wheel and is specific to each pocket (i.e. each pocket has its own contrast, i.e. its own transverse support element) makes the setting phase is more complex (and therefore more time-consuming) as it is necessary to finely adjust the position of each contrast (i.e. of each transverse support element) to cooperate optimally with at least one mobile welder that is external to the wheel of wrapping and is common to all budgets; that is, it is necessary to repeat the fine adjustment of the position of each contrast (i.e. of each transverse support element) with respect to the common movable welder. Furthermore, the fact that the contrast used during heat sealing (i.e. the transverse support element) is mounted on the wheel requires the replacement of a greater number of parts due to wear and / or format change as there is a corresponding one for each pocket. contrast. Finally, the fact that the contrast used during heat sealing (i.e. the transverse support element) is mounted on the wheel determines a lower repeatability of the product quality (as the welding operation can change from pocket to pocket); in other words, the same wrapping wheel can produce both perfectly sealed and unsatisfactorily sealed wrappers.

It is important to note that the aforementioned drawbacks are accentuated as the hourly productivity of the packaging machine increases, since by increasing the hourly productivity the time available to perform the heat sealing decreases and therefore the heat sealing itself is of good quality only if the mobile welder common is mechanically coupled in an optimal way with the corresponding contrato (or with the corresponding transversal support element). Consequently, the packing machine described in patent application WO2010136869A1 is not suitable for operating with very high hourly productivity.

DESCRIPTION OF THE INVENTION

The object of the present invention is to provide a wrapping method and a packaging machine for folding a sheet of heat-sealable wrapping around a group of smoking articles, which wrapping method and packaging machine are free of the drawbacks described above and are, at the same time, easy and inexpensive to make.

In accordance with the present invention, a wrapping method and a packing machine are provided for folding a sheet of heat-sealable wrapping around a group of smoking articles, as claimed in the attached claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described with reference to the attached drawings, which illustrate some non-limiting examples of implementation, in which:

Figure 1 illustrates a front perspective view of a cigarette wrapping made according to the wrapping method of the present invention;

Figure 2 illustrates a perspective view of a group of cigarettes contained in the wrapping of Figure 1;

Figure 3 illustrates a perspective view of a reinforcement element that can be contained in the wrapping of Figure 1;

Figure 4 illustrates a plan view of a sheet of wrapping used to make the wrapping of Figure 1;

Figures 5-10 illustrate some steps of the wrapping method of the present invention to fold the wrapping sheet of Figure 4 around the group of cigarettes of Figure 2 in order to obtain the cigarette wrapping of Figure 1;

Figure 11 is a schematic and perspective view of a packaging machine that produces the wrapping of Figure 1 and is made in accordance with the present invention;

Figure 12 is an enlarged scale view of a wrapping wheel of the packing machine of Figure 11;

Figure 13 is a schematic and perspective view of an alternative embodiment of a packaging machine made in accordance with the present invention;

Figure 14 is an enlarged scale view of a wrapping wheel of the packing machine of Figure 13;

figure 15 is a schematic and perspective view of a further embodiment of a packaging machine which produces the wrapping of figure 1 and is made in accordance with the present invention; And

Figure 16 is a schematic and perspective view of another embodiment of a packaging machine made in accordance with the present invention.

PREFERRED FORMS OF IMPLEMENTATION OF THE INVENTION

In figure 1, the number 1 indicates as a whole a sealed cigarette wrapping, for example of the type described in US patent 4300676A1.

According to what is illustrated in Figure 2, the cigarette pack 1 encloses a group 2 of cigarettes having a parallelepiped shape and having an upper wall 3 and a lower wall 4 which are constituted by the tips of the cigarettes and are parallel and opposite to each other, two walls 5 and 6 major side walls which are constituted by the cylindrical side walls of the cigarettes and are parallel and opposite to each other, and two minor side walls 7 and 8 which are constituted by the cylindrical side walls of the cigarettes and are parallel and opposite to each other. According to a preferred embodiment, the upper wall 3 of the group 2 of cigarettes is arranged in correspondence with the cigarette filters, while the lower wall 4 of the group 2 of cigarettes is arranged at the tips of the cigarettes (i.e. the ends of the cigarettes with tobacco in sight).

According to what is illustrated in Figures 1 and 4, the wrapper 1 has a cigarette extraction opening 9 at the top and front (visible in Figure 4), which is delimited by a pre-weakened tear-off line, and is closed by a label 10 of reusable closure and involves a portion of a front wall of the wrapper 1 and a portion of an upper wall of the wrapper 1. According to a preferred embodiment, the closure label 10 is fixed to the cigarette wrapper 1 by means of a repositionable adhesive that does not dry, which is applied to the lower surface of the closure label 10 and is arranged all around the extraction opening 9 to allow the closure label 10 to be partially separated from the wrapper 1 several times and then re-fixed in wrapper 1.

Wrapping 1 is made by folding a rectangular sheet 11 of wrapping (shown in Figure 4) around the group 2 of cigarettes (shown in Figure 2). Before folding the wrapping sheet 11 around the cigarette group 2, the wrapping sheet 11 itself is centrally pre-scored to define the extraction opening 9; subsequently, the rubberized closing label 10 is applied to the wrapping sheet 11, i.e. provided in its lower surface with the repositionable adhesive which inside the extraction opening 9 determines the permanent bonding of the inner portion of the wrapping sheet 11 to the closing label 10 and on the outside of the extraction opening 9 determines a separable gluing of the wrapping sheet 11 to the closing label 10

According to what is illustrated in Figure 3, the wrapping 1 could include a reinforcing element 12, which is made of cardboard or rigid cardboard, is shaped like a "U" and is arranged inside the wrapping 1 in contact with the group 2 of cigarettes. The function of the reinforcing element 12 is to give greater stiffness and greater stability of shape to the wrapping 1 so as to prevent the wrapping 1 from collapsing on itself after having extracted a part of the cigarettes contained in the wrapping 1 making the extraction of the remaining cigarettes is complicated and in particular making the opening and subsequent reclosing of the closure label 10 extremely complicated. A further function of the reinforcing element 12 is to provide mechanical protection to the cigarettes during the folding of the wrapping sheet 11, a mechanical and thermal protection to the cigarettes during the heat sealing of the overlapping portions of the wrapping sheet 11, and a mechanical protection to the cigarettes when handling the wrapping 1.

Figures 5-8 illustrate the steps of folding the wrapping sheet 11 around the group 2 of cigarettes which has the two major side walls 5 and 6 which are opposite to each other and consist of the cylindrical side walls of the cigarettes, and the two upper and lower walls 3 and 4 which are opposite to each other and are constituted by the tips of the cigarettes.

Initially, the cigarette group 2 is coupled to the stretched wrapping sheet 11 by bringing the upper wall 3 of the cigarette group 2 into contact with the wrapping sheet 11 (Figure 5); subsequently, the wrapping sheet is folded in a "U" shape around the group 2 of cigarettes (figure 6) so that the wrapping sheet 11 folded into a "U" shape is arranged in correspondence with the upper wall 3 and the two walls 5 and 6 larger side walls of group 2 of cigarettes and present two ends 13 and 14 which are parallel to the major side walls 5 and 6 and protrude from the major side walls 5 and 6 themselves (i.e. they continue beyond the major side walls 5 and 6 themselves; it is important observe that the wrapping sheet 11 is fed asymmetrically in front of the group 2 of cigarettes (i.e. the wrapping sheet 11 is placed asymmetrically against the upper wall 3 of the group 2 of cigarettes) to define the two ends 13 and 14 which both protrude from the group 2 of cigarettes and have a different length (i.e. the end 13 is longer than the end 14 and the difference in length between the end 13 and the end 14 is equal to the larghez za of the lower wall 4 of the group 2 of cigarettes). As shown in Figure 6, the end 13 is parallel to the greater side wall 6 of the group 2 of cigarettes and exits from the lower wall 4 of the group 2 of cigarettes continuing beyond the greater side wall 6; similarly, the end 14 is parallel to the greater side wall 5 of the group 2 of cigarettes and exits from the lower wall 4 of the group 2 of cigarettes continuing beyond the greater side wall 5. As shown in Figure 7, the end 13 is folded by 90 ° with respect to the greater side wall 6 of the group 2 of cigarettes and against the lower wall 4 of the group 2 of cigarettes and, at the same time, a final part of the end 13 to give the end 13 an "L" shape and then arrange the final part of the end 13 parallel and resting on the end 14 (which does not undergo, in this phase, any type of bending, ie it remains parallel to the side wall 5 greater) giving the wrapping sheet 11 a tubular shape; in other words, at the same time (i.e. with the same bending action) the end 13 is bent by 90 ° in two distinct points: a first bending of 90 ° around the corner between the greater side wall 6 and the lower wall 4 and a second fold at the corner between the larger side wall 5 and the lower wall 4 (ie near the end 14) in such a way as to give the end 13 an "L" shape and rest the final part of the end 13 against the end 14. When the end 13 is folded into an "L" shape and rests (in its final part) on the end 14, the wrapping sheet 11 is given a tubular shape presenting two side edges open in correspondence with the walls 7 and 8 minor side of the group 2 of cigarettes. At this point, as illustrated in Figure 8, the superimposed portions of the ends 13 and 14 are heat-sealed together to stabilize the tubular shape of the wrapping sheet 11 and form a sealing fin F. Finally, the ends 13 and 14 overlapped and heat-sealed (i.e. the welding fin F) are folded by 90 ° against the lower wall 4 of the group 2 of cigarettes (as shown in Figure 9) and with the interposition of part of the wrapping sheet 11; alternatively, the ends 13 and 14 overlapped and heat-sealed (i.e. the welding fin F) are folded by 180 ° against the larger side wall 5 of the group 2 of cigarettes (as shown in Figure 10) and with the interposition of part of sheet 11 of wrapping.

In figure 11, the number 15 indicates as a whole a packing machine that produces the wrapping 1 of cigarettes illustrated in figure 1 following the wrapping steps illustrated in figures 5-9.

It is important to underline that the packaging machine 15 could only comprise the components illustrated in figure 11 (in this case each package 1 described above is a finished and directly marketable product); alternatively, the packing machine 15 could comprise further components of a known type for wrapping around each wrapping 1 a respective outer wrapping, which encloses the wrapping 1 and can consist of an outer wrapping sheet folded around the wrapping 1 and cup-shaped (soft-type cigarette packet), or it may consist of a rigid box with a hinged lid formed by folding a rigid blank around the wrapper 1 (rigid-type cigarette packet).

The packing machine 15 comprises a forming unit 16 in which the groups 2 of cigarettes are formed in succession, a preliminary folding unit 17 in which a corresponding sheet 11 of wrapping is folded around each group 2 of cigarettes, a transverse folding unit 18 in which each sheet 11 of wrapping is folded transversely at the lower wall 4 of the respective group 2 of cigarettes to form a tubular package, and a longitudinal folding unit 19 in which each sheet 11 of wrapping is folded longitudinally in correspondence with the minor lateral walls 7 and 8 of the respective group 2 of cigarettes to complete the formation of the package 1.

The packing machine 15 comprises a wrapping conveyor 20, which comprises a plurality of pockets (known and not illustrated) which are adapted to house corresponding groups 2 of cigarettes and are advanced step by step (i.e. with a law of motion which cyclically alternates a movement phase and a stop phase) along a wrapping path P1 which passes through the forming unit 16 and the preliminary folding unit 17. Preferably, the pockets protrude from the wrapping conveyor 20, i.e. each pocket is fixed to the wrapping conveyor 20 only at a first end and a second end opposite the first end is free from constraints with the wrapping conveyor 20 and relatively away from the wrapping conveyor 20 itself. In the non-limiting embodiment illustrated in the attached figures, the wrapping conveyor 20 comprises a belt, which is wound around end pulleys (one of which is motorized) and moves stepwise along a closed loop path; alternatively, the wrapping conveyor 20 comprises a wheel mounted to rotate around a central axis of rotation. The unit 16 for forming the groups 2 of cigarettes comprises a hopper (schematically illustrated) provided with three outlets for simultaneously feeding three groups 2 of cigarettes to respective pockets of the wrapping conveyor 20 which advances step by step along the wrapping path P1 . The preliminary folding unit 17 is arranged along the wrapping conveyor 20 (i.e. along the wrapping path P1) downstream of the forming unit 16. In the preliminary folding unit 17 each group 2 of cigarettes carried by a pocket is coupled to the corresponding sheet 11 of unfolded wrapping and resting the wrapping sheet 11 itself on the upper wall 3 of the group 2 of cigarettes (as illustrated in Figure 5); subsequently, the wrapping sheet 11 is folded in a "U" shape around the group 2 of cigarettes (as illustrated in Figure 6).

In the preliminary folding unit 17, the wrapping sheet 11 can immediately take the form illustrated in Figure 6 (i.e. in which both sides of the wrapping sheet 11 adhere to the larger side walls 5 and 6 of the group 2 of cigarettes, forming corners of 90 ° fold), or (as shown in Figure 11) the wrapping sheet 11 may initially assume a more open shape in which one side of the wrapping sheet 11 is raised with respect to the larger side wall 5 or 6 of the group 2 of cigarettes forming a folding angle greater than 90 ° and therefore can assume the final shape illustrated in Figure 6 (i.e. in which both sides of the wrapping sheet 11 adhere to the larger side walls 5 and 6 of the group 2 of cigarettes, forming folding angles 90 °) when the group 2 of cigarettes leaves the corresponding pocket of the wrapping conveyor 20 together with the wrapping sheet 11.

The transverse folding unit 18 comprises a wrapping conveyor 21, which receives the wrappers 1 in succession (each consisting of a sheet 11 of wrapping folded in a "U" shape around a corresponding group 2 of cigarettes) from the wrapping conveyor 20 in a transfer station S1 and successively advances the wrappers 1 along a folding path P2 which is circular. In particular, the wrapping conveyor 21 comprises a wrapping wheel 22 which rotates step by step (i.e. with a law of motion which cyclically alternates a movement phase and a stop phase) around a central rotation axis 23 and is provided with a plurality of peripheral pockets each suitable for housing a corresponding partially formed wrapping 1 (ie a group 2 of cigarettes partially wrapped in a wrapping sheet 11).

In other words, each group 2 of cigarettes wrapped in the U-folded wrapping sheet 11 is inserted into a pocket of the wrapping wheel 22 (that is, in a pocket of the wrapping conveyor 21) which advances along the wrapping path P2 to to realize the bending of the two ends 13 and 14 and then to realize the heat sealing which constitutes the welding fin F. When the group 2 of cigarettes is arranged in a pocket of the wrapping wheel 22 (i.e. in a pocket of the wrapping conveyor 21), the welding fin F, i.e. the final part of the end 13 and the end 14, are arranged parallel to the wrapping path P2 (at least until the heat sealing is complete, i.e. until the welding fin F is completely formed). In other words, when the group 2 of cigarettes is arranged in a pocket of the wrapping wheel 22 (i.e. in a pocket of the wrapping conveyor 21), the two major side walls 5 and 6 of the group 2 of cigarettes are arranged parallel to the path P2, the two smaller side walls 7 and 8 of the cigarette group 2 are arranged perpendicularly to the wrapping path P2, and the upper wall 3 and the lower wall 4 of the cigarette group 2 are arranged parallel to the wrapping path P2.

As illustrated in Figure 12, a folding device 24 is arranged along the wrapping conveyor 21, or along the wrapping path P2, and immediately downstream of the transfer station S1, which performs the double folding of the end 13 of the sheet 11 of wrapping illustrated in Figure 7 and described previously which gives the end 13 to the "L" shape; in other words, the folding device 24 folds the end 13 by 90 ° with respect to the larger side wall 6 of the group 2 of cigarettes and, at the same time, folds the final part of the end 13 into an "L" shape to arrange the final part of the end 13 against end 14 which does not undergo, in this step, any type of bending. According to a preferred embodiment, the folding device 24 is of the passive type (ie it is completely devoid of moving parts) and comprises only fixed folding helices.

As illustrated in Figure 12, along the wrapping conveyor 21, or along the wrapping path P2, and immediately downstream of the folding device 24, there is a sealing device 25, which performs the heat-sealing of the superimposed portions of the ends 13 and 14 (that is, it realizes the welding fin F) to stabilize the tubular shape of the wrapping sheet 11 as illustrated in figure 8. According to a preferred embodiment illustrated in figure 8, the welder device 25 comprises a welding gun 26 provided with two jaws 27 mobile and heated: during the advancement phase of the wrapping conveyor 21 the welding gripper 26 is open (i.e. the two jaws 27 are relatively far from each other) to allow the ends 13 and 14 of the wrapping sheet 11 (i.e. the fin F welding) to pass through the welding gun 26 without sliding, while during the stop phase of the conveyor 21 of the n paper, the welding gripper 26 is closed (i.e. the two jaws 27 are pushed against each other with a certain force to tighten the ends 13 and 14 of the wrapping sheet 11 together) to perform the heat sealing (due to the simultaneous application of heat and pressure) of the overlapping portions of the ends 13 and 14 of the wrapping sheet 11. It is important to note that a single welder device 25 is provided, or a welding gripper 26, which is arranged in a fixed position along the wrapping conveyor 21, or along the wrapping path P2, and is in any case to all wrappers 1; in other words, all the wrappers 1 are heat-sealed at the ends 13 and 14 of the wrapping sheet 11 (ie the welding fins F) by a single common welder device 25. According to a possible embodiment, the folding device 24 only folds the end 13 of the wrapping sheet 11, giving the end 13 itself an "L" shape (as illustrated in Figure 7), leaving the sealing device 25 with the task of perform the heat sealing of the superimposed portions of the ends 13 and 14. According to an alternative embodiment, the folding device 24 could also comprise (at least) a heated element to carry out, at the same time, both the folding of the end 13 of the wrapping sheet 11 giving the end 13 itself an "L" shape (as illustrated in Figure 7), and an initial heat sealing of the superimposed portions of the ends 13 and 14; subsequently, the welder device 25 completes the heat sealing of the superimposed portions of the ends 13 and 14 initiated by the folding device 24.

In the embodiment illustrated in the attached figures, the transverse folding unit 18 comprises a single welder device 25 placed immediately downstream of the folding device 24; according to a different and perfectly equivalent embodiment, the transverse folding unit 18 comprises two or more (typically no more than three) welding devices 25 arranged in succession immediately downstream of the folding device 24.

As shown in Figure 12, a folding device 28 is arranged along the wrapping conveyor 21, or along the wrapping path P2, and immediately downstream of the sealing device 25, which bends the flaps 13 and 14 by 90 °. superimposed and heat-sealed together (ie the welding fin F) illustrated in figure 9; in other words, the folding device 28 folds the edges 13 and 14 overlapped and heat-sealed (i.e. the welding fin F) by 90 ° against the lower wall 4 of the group 2 of cigarettes and with the interposition of part of the sheet 11 of wrapping. According to a preferred embodiment, the folding device 28 is of the passive type (ie it is completely devoid of moving parts) and comprises only fixed folding propellers.

As illustrated in Figure 12, the wrapping conveyor 21 advances each wrapping 1 (constituted, in correspondence with the wrapping conveyor 21, by a group 2 of cigarettes partially wrapped in a wrapping sheet 11) in such a way that the walls 3 and 4 upper and lower and the major side walls 5 and 6 of the cigarette group 2 are parallel to the wrapping path P2 and the minor lateral walls 7 and 8 of the cigarette group 2 are perpendicular to the wrapping path P2; in other words, the wrapping conveyor 21 advances each wrapping 1 in such a way that the ends 13 and 14 of the wrapping sheet 11 (ie the sealing fin F) are (at least up to the heat-sealing) parallel to the wrapping path P2.

According to what is illustrated in Figure 11, at the end of the transverse folding unit 18 (i.e. at the entrance to the longitudinal folding unit 19) each package 1 has a tubular shape presenting two side edges open in correspondence with the smaller side walls 7 and 8 of the group 2 of cigarettes. The longitudinal folding unit 19 comprises a wrapping conveyor (known and not illustrated), which receives in succession the wrappers 1 (each consisting of a sheet 11 of wrapping folded into a tube around a corresponding group 2 of cigarettes) from the conveyor 21 of longitudinal wrapping in a transfer station S2 and advances along a folding path P3 which is rectilinear and is arranged perpendicular to the folding path P2. The transfer station S2 is opposite the transfer station S1 and is arranged at 180 ° along the wrapping path P2 with respect to the transfer station S1 itself. The longitudinal folding unit 19 comprises folding devices (known and not illustrated) which fold in a known way the two open side edges of each package 1 to complete the formation of the package 1 itself; preferably, the folding devices of the longitudinal folding unit 19 are passive (ie they are completely devoid of moving parts) and comprise only fixed folding helices. The longitudinal folding unit 19 comprises welding devices (known and not illustrated) that stabilize each package 1 by heat sealing the overlapping portions of the wrapping sheet 11 at the smaller side walls 7 and 8 of the group 2 of cigarettes.

Along the transversal folding unit 18 the groups 2 of cigarettes are advanced transversely (i.e. the cigarettes are arranged perpendicular to the wrapping path P2), while along the longitudinal folding unit 19 the groups 2 of cigarettes are advanced longitudinally (i.e. cigarettes are arranged parallel to the wrapping path P3).

In the non-limiting embodiment illustrated in the attached figures, the longitudinal folding unit 19 comprises a rectilinear wrapping conveyor having pushers that advance the wrappers 1 through a fixed folding tunnel; alternatively, the longitudinal folding unit 19 comprises a circular wrapping conveyor (i.e. a wrapping wheel mounted rotatable around a central rotation axis).

As shown in Figure 11, the preliminary folding unit 17 comprises a feed conveyor, which advances the wrapping sheets 11 in succession along a straight feed path P4; by way of example, the feed conveyor comprises two conveyor belts which are closed in a loop, are arranged at opposite ends of the wrapping sheets 11, and hold the wrapping sheets 11 by suction. The feed path P4 has a section parallel to and adjacent to the wrapping path P1 at a feed station S3 in which each wrapping sheet 11 is transferred from the feed conveyor to a pocket of the wrapping conveyor 20 to be coupled, as described above, to a corresponding group 2 of cigarettes. Coupled to the wrapping conveyor 20 is a folding device (known and not illustrated) which folds the wrapping sheet 11 in a "U" shape around the group 2 of cigarettes as previously described. According to an alternative and perfectly equivalent embodiment not shown, each sheet 11 of wrapping is fed flat at the transfer station S1 and folds in a "U" shape around the group 2 of cigarettes as described above, while the group 2 of cigarettes itself fits into a pocket of the wrapping wheel 22.

As shown in Figure 11, when the reinforcement element 12 is provided, each reinforcement element 12 itself is fed to the corresponding pocket of the wrapping conveyor 20 upstream of the hoppers or before feeding the group 2 of cigarettes to the pocket.

In the alternative embodiment illustrated in Figure 13, the coupling methods of the wrapping sheets 11 to the groups 2 of cigarettes in the feeding station S3 are modified, the folding methods of the ends 13 and 14 overlapping and heat-sealed (i.e. of the welding fin F), and the folding modes of the two open side edges of each package 1 in the longitudinal folding unit 19 are modified. In the feeding station S3, each group 2 of cigarettes is coupled to the corresponding sheet 11 of unfolded wrapping by placing a side part of the wrapping sheet 11 on the larger side wall 5 of the group 2 of cigarettes; subsequently, the sheet 11 of wrapping is folded in a "U" shape around the corresponding group 2 of cigarettes to form a "U" -shaped wrapping 1 having the two ends 13 and 14 protruding out of the group 2 of cigarettes. The ends 13 and 14 overlapped and heat-sealed (i.e. the welding fin F) are folded by 180 ° against the larger side wall 5 of the group 2 of cigarettes (as also illustrated in Figure 10) and with the interposition of part of the 11 sheet of wrapping. In the longitudinal folding unit 19 two fin folds are made which are welded together while they are perpendicular to the corresponding smaller side walls 7 and 8 of the group 2 of cigarettes and, after heat sealing, are folded 90 ° against the walls 7 and 8 minor laterals themselves.

As illustrated in Figure 14, each pocket of the wrapping wheel 22 is provided with a pair of retainers 29 which are arranged on opposite sides of the pocket and are movable between an open position (assumed at the transfer stations S1 and S2) in which the two retainers 29 are relatively distant from each other to allow the partially formed wrapper 1 to enter / exit the pocket without interfering with the retainers 29 themselves, and a closed position (assumed outside the transfer stations S1 and S2) in in which the two retainers 29 are relatively close to each other to "pinch" the group 2 of cigarettes together and thus keep the group 2 of cigarettes laterally compressed to prevent the group 2 of cigarettes from deforming. The function of the pair of retainers 29 of each pocket of the wrapping wheel 22 is to keep the group 2 of cigarettes laterally compressed during the advancement of the wrapping wheel 22 without, at the same time, subjecting the wrapping sheet 11 to undesired folding at the same time. of the open side edges.

With the folding methods of the open lateral edges adopted in the embodiment illustrated in Figure 11, an initial folding of the wrapping sheet 11 is already made in the wrapping wheel 22 at the open lateral edges (the fold of the so-called "nibs") , therefore, the pockets 23 of the wrapping wheel can comprise fixed profiles which on the one hand make this initial folding of the wrapping sheet 11 (i.e. they fold the "nibs") and on the other side ensure the lateral compression of the group 2 of cigarettes for prevent group 2 of cigarettes from deforming. On the other hand, with the methods of folding the open side edges adopted in the embodiment illustrated in Figure 13, in the wrapping wheel 22 no folding of the wrapping sheet 11 must be made at the open lateral edges and therefore it is necessary to use the retainers. 29 which open and close to push laterally only on the group 2 of cigarettes without affecting the wrapping sheet 11 (ie without causing bending of the wrapping sheet 11).

As illustrated in Figure 14, a straight wrapping conveyor 30 can be provided (for example a belt conveyor) provided with pockets 31 suitable for receiving and holding the wrapping 1. The wrapping conveyor 30 extends along the wrapping path P3 and extends from the transfer station S1, through the transfer station S2, and along the entire longitudinal folding unit 19. Furthermore, the wrapping conveyor 30 is arranged perpendicularly to the rotation axis 23 of the wrapping wheel 22 and passes through the rotation axis 23 of the wrapping wheel 22 (i.e. it crosses the wrapping wheel 22 from side to side, passing through the axis 23 of rotation of the wrapping wheel 22 and passing through both the transfer station S1 and the transfer station S2).

The main function of the wrapping conveyor 30 is to advance the wrappers 1 along the entire longitudinal folding unit 19, or to receive the wrappers 1 from the wrapping wheel 22 in the transfer station S2 and to advance the wrappers 1 along the path P3 of wrapping. It is important to note that, in the transfer station S2, a pocket 31 of the wrapping conveyor 30 passes through a pocket of the wrapping wheel 22, picking up a corresponding wrapping 1 directly (i.e. without the presence of further pushers / transfers). function of the wrapping conveyor 30 is to transfer the wrappers 1 from the preliminary folding unit 17 to the transverse folding unit 18 in the transfer station S1, or to extract, in the transfer station S1, a wrapper 1 from the pocket of the wrapping from the preliminary folding unit 17 by subsequently inserting the wrapping 1 into the pocket of the wrapping wheel 22; in particular, in the transfer station S1 a pocket 31 of the wrapping conveyor 30 passes through a pocket of the wrapping conveyor from the preliminary folding unit 17 to pick up the wrapping 1 and then passes through a pocket of the wrapping wheel 22 to release wrapping 1. In other words, the wrapping conveyor 30 is adapted to insert a group 2 of cigarettes coupled to a wrapping sheet 11 in a pocket of the wrapping wheel 22 in the transfer station S1, and the wrapping conveyor 30 is adapted to take a group 2 of cigarettes coupled to a wrapping sheet 11 from a pocket of the wrapping wheel 22 in the transfer station S2 opposite the transfer station S1 and arranged at 180 ° along the wrapping path P2 with respect to the station S1 transfer itself.

It is important to note that the straight wrapping conveyor 30 illustrated in Figure 14 can be used both in the embodiment illustrated in Figure 13 and in the embodiment illustrated in Figure 11.

Figure 15 illustrates a variant of the embodiment illustrated in Figure 11, in which the conveyor 21 of the transverse folding unit 18 is straight and not circular.

Figure 16 shows a variant of the embodiment illustrated in Figure 13, in which the conveyor 21 of the transverse folding unit 18 is straight and not circular.

In the embodiments illustrated in the attached figures, the wrapping sheet 11 is folded from the beginning around the cigarette group 2, or the folds of the wrapping sheet 11 are all performed against the cigarette group 2. According to an alternative and perfectly equivalent embodiment, each pocket of the wrapping conveyor 20 is constituted by a hollow folding mandrel, which is able to contain a group 2 of cigarettes and around which the sheet is initially folded into a "U" 11 of wrapping; in other words, a sheet 11 of wrapping is initially folded into a "U" shape (in the same manner described above) around a folding mandrel (constituting a pocket of the wrapping conveyor 20) which contains a group 2 of cigarettes and the group 2 of cigarettes is coupled to the wrapping sheet 11 already folded in a "U" shape against the bending mandrel at the transfer station S1 (ie at the moment of entry into a pocket of the wrapping conveyor 21). In this embodiment, the initial "U" folding of each sheet 11 of wrapping takes place against a folding mandrel, a group 2 of cigarettes is coupled to the sheet 11 of "U" folded wrapping at the transfer station S1 ( or at the moment of entry into a pocket of the wrapping conveyor 21), and the folding of the wrapping sheet 11 is completed against the group 2 of cigarettes.

The packaging machine 15 described above has numerous advantages. In the first place, the packing machine 15 described above is capable of operating rapidly (ie with a high hourly productivity) while ensuring a high and above all constant production quality. This result is obtained thanks to the fact that both in the transversal folding unit 18 and in the longitudinal folding unit 19 there is a single common sealing device which is external to the corresponding wrapping conveyor (i.e. it does not move together with the wrapping conveyor but remains always in the same position) and therefore operates with all the wrappers 1. Thanks to this expedient, when setting up the packing machine 15 it is sufficient to finely adjust a single common sealing device for each folding unit 18 and 19, and therefore it is on average it is possible to achieve higher quality standards.

Furthermore, in the packaging machine 15 described above, the realization of the wrapping conveyor 21 of the transversal folding unit 18 is very simple, since the wrapping conveyor 21 does not have to support mobile heating parts; among other things it is important to underline that it is not necessary to bring electrical power to the wrapping conveyor 21 since there are no heating elements on board the wrapping conveyor 21.

Claims (16)

Finally, in the packaging machine 15 described above, the operation of replacing the sealing device 25 of the transversal folding unit 18 is greatly simplified and speeded up (in case of format change or in case of maintenance), since the sealing device 25 comprises a single sealing gripper 26 common to all the pockets of the wrapping wheel 22. It is important to note that also the folding methods of the wrapping sheet 11 around the group 2 of cigarettes allow to improve the final quality of the folding process, as they allow to obtain a very precise positioning of the wrapping sheet 11 with respect to the group 2. of cigarettes even when operating rapidly (i.e. with a high hourly productivity); consequently, in the wrappers 1 the extraction opening 9 (surmounted by the reusable closure label 10) is always exactly in the desired position. The embodiment illustrated in the attached figures refers to the production of a packet of cigarettes, but the present invention can also be applied without substantial modifications to the production of any other type of packet of smoking articles (for example a pack of cigars, a pack of electronic cigarettes of the liquid vaporization type, a pack of new generation cigarettes without tobacco combustion ...). R I V E N D I C A Z I O N I 1) Wrapping method for folding a sheet (11) of wrapping around a group (2) of parallelepiped-shaped smoking articles, which has an upper wall (3) and a lower wall (4) parallel and opposite to each other , two major lateral walls (5, 6) parallel and opposite to each other, and two minor lateral walls (7, 8) parallel and opposite to each other; The wrapping method comprises the step of arranging the U-folded wrapping sheet (11) around the group (2) of smoking items so that the U-folded wrapping sheet (11) is arranged in a correspondence with the upper wall (3) and the two major lateral walls (5, 6) of the group (2) of smoking articles and present two ends (13, 14) which are parallel to the major lateral walls (5, 6) and protrude from the major lateral walls (5, 6) themselves; overlapping the two ends (13, 14) of the wrapping sheet (11) with each other, giving the wrapping sheet (11) a tubular shape; And heat-sealing the superimposed portions of the two ends (13, 14) of the wrapping sheet (11) to stabilize the tubular shape of the wrapping sheet (11) and constitute a welding fin (F); in which the two ends (13, 14) are superimposed and heat-sealed while the group (2) of smoking articles coupled to the wrapping sheet (11) is housed in a first pocket of a first wrapping conveyor (21) which advances along a wrapping path (P2); the wrapping method is characterized by the fact that the first pocket of the first wrapping conveyor (21) is oriented in such a way that the sealing fin (F), i.e. the overlapping portions of the two ends (13, 14) of the sheet (11 ) of wrapping, is arranged parallel to the wrapping path (P2) at least until the completion of the heat sealing. 2) Wrapping method according to claim 1, wherein when the group (2) of smoking articles is arranged in the first pocket of the first wrapping conveyor (21): the two major lateral walls (5, 6) of the group (2) of smoking articles are arranged parallel to the wrapping path (P2); the two smaller lateral walls (7, 8) of the group (2) of smoking articles are arranged perpendicularly to the wrapping path (P2); And the upper wall (3) and the lower wall (4) of the group (2) of smoking articles are arranged parallel to the wrapping path (P2). 3) Wrapping method according to claim 1 or 2, wherein a first folding device (24) is provided which is arranged externally to the first wrapping conveyor (21) and folds the two ends (13, 14) against each other of the wrapping sheet (11). 4) Wrapping method according to claim 1, 2 or 3, wherein a sealing device (25) is provided which is arranged externally to the first wrapping conveyor (21) and heat-seals the superimposed portions of the two ends (13, 14) of the wrapping sheet (11) to form the sealing fin (F) when the first pocket of the first wrapping conveyor (21) is in correspondence with the welder device (25) itself. 5) Wrapping method according to one of claims 1 to 4, wherein a second folding device (28) is provided which is arranged externally to the first wrapping conveyor (21) and folds the sealing fin (F) when the first pocket of the first wrapping conveyor (21) is located in correspondence with the second folding device (28) itself. Wrapping method according to one of claims 1 to 5, wherein the first wrapping conveyor (21) comprises a wrapping wheel (22) mounted rotatably about a central rotation axis (23). 7) Wrapping method according to claim 6, wherein: a second conveyor (30) of rectilinear wrapping is provided provided with a second pocket (31) adapted to receive and hold the group (2) of smoking articles coupled to the wrapping sheet (11); and the second wrapping conveyor (30) is arranged perpendicular to the axis (23) of rotation of the wrapping wheel (22) and passes through the axis (23) of rotation of the wrapping wheel (22). 8) Wrapping method according to claim 7, wherein: the second wrapping conveyor (30) is adapted to insert the group (2) of smoking articles coupled to the wrapping sheet (11) in the first pocket of the wrapping wheel (22) in a first transfer station (S1); and the second wrapping conveyor (30) is adapted to pick up the group (2) of smoking articles coupled to the wrapping sheet (11) from the first pocket of the wrapping wheel (22) in a second transfer station (S2) opposite the first transfer station (S1) and arranged at 180 ° along the wrapping path (P2) with respect to the first transfer station (S1) itself. 9) Wrapping method according to one of claims 1 to 8, wherein the pocket of the first wrapping conveyor (21) is provided with a pair of retainers (29) which are arranged on opposite sides of the pocket and are movable between positions open in which the two retainers (29) are relatively far from each other to allow the wrapping sheet (11) coupled to the group (2) of smoking articles to enter / exit the pocket without interfering with the retainers (29) themselves, and a closed position in which the two retainers (29) are relatively close to each other to lock together the group (2) of smoking articles by leaning against the smaller lateral walls (7, 8) of the group (2) of smoking articles. 10) Wrapping method according to one of claims 1 to 9 and comprising the further step of bending the first end (13) by 90 ° against the lower wall (4) of the group (2) of smoking articles and, at the same time, bend a final part of the first end (13) by 90 ° to give the first end (13) an "L" shape and then place the final part of the first end (13) parallel and resting on the second end (14) which it remains parallel to the second major lateral wall (5) giving the wrapping sheet (11) a tubular shape. 11) Wrapping method according to claim 10, wherein the wrapping sheet (11) is placed asymmetrically against the upper wall (3) of the group (2) of smoking articles in such a way that a first end (13) protruding from a first major lateral wall (6) is longer than a second end (14) protruding from a second major lateral wall (5). 12) Wrapping method according to claim 11, wherein the difference in length between the first end (13) and the second end (14) is equal to the width of the lower wall (4) of the group (2) of smoking articles. 13) Wrapping method according to one of claims 1 to 12 and comprising the further step of bending the welding fin (F) by 90 ° against the lower wall (4) of the group (2) of smoking items. 14) Wrapping method according to one of claims 1 to 12 and comprising the further step of bending the welding fin (F) by 180 ° against the second largest lateral wall (5) of the group (2) of smoking items. Wrapping method according to one of claims 1 to 14, wherein the wrapping sheet (11) has a cigarette extraction opening (9), which is closed by a reusable closure label (10) and is partially arranged at a larger side wall (5) of the group (2) of smoking articles and partially at the upper wall (3) of the group (2) of smoking articles. 16) Packaging machine (13) for folding a sheet (11) of wrapping around a group (2) of parallelepiped-shaped smoking articles, which has