Packer machine and wrapping method to manufacture a wrap around a group of smoking articles
The packer machine and wrapping method use fixed folding profiles and simple, linearly movable elements to achieve high-speed production of high-quality cigarette wraps with precise folds, addressing the challenges of existing technologies in producing high-quality wraps at speed and handling thicker materials.
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- GD SPA
- Filing Date
- 2025-12-05
- Publication Date
- 2026-06-10
AI Technical Summary
Existing packer machines struggle to produce high-quality cigarette wraps at high production speeds, particularly when dealing with thicker or tougher materials, and often require complex movements to fold multiple wraps simultaneously.
A packer machine and wrapping method that utilize fixed folding profiles and simple, linearly movable folding elements to create precise folds in wrapping sheets around groups of cigarettes, allowing for high-speed production of high-quality wraps without the need for additional separation or movement of multiple wraps.
Enables the production of high-quality cigarette wraps at high speeds, with precise and well-defined folds, even when handling thicker materials, and simplifies the folding process by minimizing complex movements, especially when folding multiple wraps simultaneously.
Smart Images
Figure IMGAF001_ABST
Abstract
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This patent application claims priority from Italian patent application no. 102024000027762 filed on December 6, 2024, the entire disclosure of which is incorporated herein by reference.TECHNICAL FIELD
[0002] The present invention relates to a packer machine and to a wrapping method to manufacture a wrap around a group of smoking articles.
[0003] The present invention is advantageously applied to the manufacturing of a wrap containing a group of cigarettes, to which the following disclosure will explicitly refer without thereby losing generality.PRIOR ART
[0004] Rigid packs for cigarettes with a hinged lid are the most widespread packs for cigarettes currently on the market as they are simple to manufacture, easy and practical to use, and offer good protection to the cigarettes contained on their inside.
[0005] A rigid pack for cigarettes with a hinged lid comprises a wrap consisting of a group of cigarettes wrapped in a wrapping sheet made of metallized paper and a rigid outer case which houses the wrap on its inside. The outer case consists of a cup-shaped container, which houses the group of cigarettes and has an open upper end, and a lid, which is also cup-shaped and is hinged to the container so as to rotate, with respect to the container, between an open position and a closed position of the open end.
[0006] Patent application EP3725691A1 describes a packer machine for manufacturing a rigid pack for cigarettes having: a wrap formed by folding a wrapping sheet made of metallized paper around a group of cigarettes, and an outer container formed by folding a blank and a collar around the wrap.
[0007] Patent US2969631A describes a packer machine for manufacturing a rigid pack for cigarettes by folding a blank around a group of cigarettes.DESCRIPTION OF THE INVENTION
[0008] The object of the present invention is to provide a packer machine and a wrapping method to manufacture a wrap around a group of smoking articles which allow manufacturing a high-quality wrap even operating at a high production speed (measured as packs for cigarettes produced in the time unit).
[0009] In accordance with the present invention, a packer machine and a wrapping method for manufacturing a wrap around a group of smoking articles are provided, according to what claimed in the appended claims.
[0010] The claims describe embodiments of the present invention forming integral part of the present description.BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The present invention will now be described with reference to the accompanying drawings, which illustrate a non-limiting example embodiment thereof, wherein: Figure 1 is a front perspective view of a wrap containing a group of cigarettes; Figure 2 is a perspective view of the group of cigarettes contained in the wrap of Figure 1; Figure 3 is a plan view of a wrapping sheet used to manufacture the wrap of Figure 1; Figures 4, 5 and 6 illustrate the folding sequence of the wrapping sheet of Figure 3 around the group of cigarettes of Figure 2 to complete the manufacturing of the wrap of Figure 1; Figure 7 is a schematic view of a wrapping unit which manufactures the wrap of Figure 1 and is provided in accordance with the present invention; Figures 8-12 are different perspective views, with parts removed for clarity, of a transverse folder of the wrapping unit of Figure 7; Figures 13-16 are different perspective views, with parts removed for clarity, of a different embodiment of the transverse folder of Figures 8-12; and Figures 17, 18 and 19 schematically illustrate the folding of two side-by-side wrapping sheets using the transverse folder of Figures 13-16. PREFERRED EMBODIMENTS OF THE INVENTION
[0012] In Figure 1, reference numeral 1 indicates, as a whole, a wrap which contains a group 2 of cigarettes (illustrated in Figure 2). The wrap 1 is part of a rigid pack for cigarettes and is housed in a container consisting of carboard or rigid paperboard and provided with a hinged lid.
[0013] According to what is illustrated in Figure 3, the wrap 1 is manufactured by folding around the group 2 of cigarettes a wrapping sheet 3 provided on one side with the tearable line which delimits a removable portion.
[0014] According to what is illustrated in Figure 4, the wrapping sheet 3 is initially folded in a "U"-shape around the group 2 of cigarettes defining on the two smaller side walls of the group 2 of cigarettes two open ends, each of which is delimited by a transverse flap 4 (or corner flap 4) and by two longitudinal flaps 5 and 6. Initially the transverse flap 4 is folded by 90° against the group 2 of cigarettes, then the longitudinal flap 5 is folded by 90° against the group 2 of cigarettes and on top of the previously folded transverse flap 4, and finally the longitudinal flap 6 is folded by 90° against the group 2 of cigarettes and on top of the transverse flap 4 and the longitudinal flap 5, which were previously folded (according to the folding modes known as "soap fold"); in this manner, the wrapping sheet 3 is caused to gain a tubular shape having one single open end at the upper wall (in which the cigarette filters are arranged) of the group 2 of cigarettes (as is illustrated in Figure 4). Such open end is delimited by two transverse flaps 7 (or corner flaps 7) and by two longitudinal flaps 8 and 9. Initially the transverse flaps 7 are folded by 90° against the group 2 of cigarettes (as is illustrated in Figure 5), then the longitudinal flap 8 is folded by 90° against the group 2 of cigarettes and on top of the previously folded transverse flaps 7, and finally the longitudinal flap 9 is folded by 90° against the group 2 of cigarettes and on top of the transverse flaps 7 and the longitudinal flap 8, which were previously folded (according to the folding modes known as "soap fold" and as is illustrated in Figure 6): in this manner, the folding of the wrapping sheet 3 around the group 2 of cigarettes is completed.
[0015] According to a possible embodiment, the final shape of the wrapping sheet 3 around the group 2 of cigarettes is not stabilized in any manner (namely no glue is applied to the wrapping sheet 3 and no seals are made on the wrapping sheet 3); consequently, the final shape of the wrapping sheet 3 around the group 2 of cigarettes is kept only by effect of the containing action of the outer container. Alternatively, the overlapped portions of the wrapping sheet 3 can be joined by means of sealing to manufacture a waterproof wrap 1.
[0016] In Figure 7, reference numeral 10 indicates, as a whole, a wrapping unit which is adapted to manufacture the wrap 1 described above and operates with an intermittent motion (namely a motion which entails a cyclic alternation of motion phases and stop phases).
[0017] The wrapping unit 10 comprises a wrapping conveyor 11 adapted to advance each group 2 of cigarettes along a horizontal straight wrapping path P1. In particular, the wrapping path P1 extends from a transfer station S1 in which the wrapping conveyor 11 receives each group 2 of cigarettes from a forming conveyor, passes through a feeding station S2 in which each group 2 of cigarettes couples to a corresponding wrapping sheet 3 which folds in a "U"-shape around the group 2 of cigarettes, and ends in a transfer station S3 in which each wrap 1 (formed by a wrapping sheet 3 only partially folded around a group 2 of cigarettes) leaves the wrapping conveyor 11. By way of example, the wrapping conveyor 11 comprises a conveyor belt having an annular shape, which is wound around two end pulleys (one of which is motorized) and supports a plurality of pushers, each of which is connected to the conveyor belt and is adapted to engage a rear wall of a corresponding group 2 of cigarettes for pushing the group 2 of cigarettes along the wrapping path P1.
[0018] Along the wrapping path P1 (and thus at the wrapping conveyor 11) there is the feeding station S2 in which each wrapping sheet 3 is arranged to be intercepted by a corresponding group 2 of cigarettes around which the wrapping sheet 3 folds in a "U"-shape; in other words, each group 2 of cigarettes advancing along the wrapping path P1 intercepts a corresponding wrapping sheet 3 arranged in the feeding station S2 determining the folding in a "U"-shape of the wrapping sheet 3.
[0019] The wrapping unit 10 comprises a feeding device 12 which cyclically feeds the wrapping sheets 3 into the feeding station S2, namely arranges each wrapping sheet 3 in the feeding station S2 so that the wrapping sheet 3 is intercepted by a corresponding group 2 of cigarettes advancing along the wrapping path P1.
[0020] According to what is illustrated in Figure 13, the wrapping unit 10 comprises a folding device 13 which is arranged along the wrapping path P1 downstream of the feeding station S2 and is adapted to fold two open side ends of each wrapping sheet 3 folded in a "U"-shape around a corresponding group 2 of cigarettes for forming a tubular wrap having an open end (as is illustrated in Figure 4). Preferably, the folding device 13 comprises only folding profiles (namely folding spirals) of known type which are fixed (i.e. totally devoid of parts in movement) and are arranged parallel to the wrapping path P1 and on opposite sides of the wrapping path P1. With reference to Figure 4, on each side of the wrapping sheet 3 folded in a "U"-shape around a corresponding group 2 of cigarettes, the folding device 13 initially folds the transverse flap 4, then folds the longitudinal flap 5, and finally folds the longitudinal flap 6. At the end of the action of the folding device 13, a wrapping sheet 3 has the tubular shape illustrated in Figure 4 having one single open end delimited by two transverse flaps 7 (or corner flaps 7) and by two longitudinal flaps 8 and 9.
[0021] According to what is illustrated in Figure 14, the wrapping unit 10 comprises a wrapping conveyor 14 adapted to advance each wrap 1 being formed (consisting of a wrapping sheet 3 only partially folded around a group 2 of cigarettes) along a horizontal straight wrapping path P2 perpendicular to the wrapping path P1. In particular, the wrapping path P2 extends from the transfer station S3 in which the wrapping conveyor 14 receives each wrap 1 being formed from the wrapping conveyor 11 and ends in a transfer station S4 in which each completed wrap 1 leaves the wrapping conveyor 14. The wrapping conveyor 14 comprises a conveyor belt having an annular shape, which is wound around two end pulleys (one of which is motorized) and supports a plurality of pockets 15, each of which is integral with the conveyor belt and is adapted to contain a wrap 1 being formed; namely each pocket 15 centrally comprises a cavity 16 shaped to house a wrap 1 being formed (as is better illustrated in Figure 16).
[0022] The wrapping unit 10 comprises a folding device 17 which is arranged along the wrapping path P2 and is adapted to complete a fold of each wrapping sheet 3 around the corresponding group 2 of cigarettes (and thus terminate the manufacturing of the wrap 1) so as to close the open end (namely left previously open by the folding device 13). The folding device 17 initially folds the transverse flaps 7 by means of a transverse folder 18 (better described in the following) as is illustrated in Figure 5, subsequently folds the longitudinal flap 8 by means of a longitudinal folder 19, and finally folds the longitudinal flap 9 by means of a longitudinal folder 20 as is illustrated in Figure 6.
[0023] Preferably, the longitudinal folding devices 19 and 20 only comprise folding profiles (namely folding spirals) of known type which are fixed (i.e. totally devoid of parts in movement) and are arranged parallel to the wrapping path P2. Alternatively, the longitudinal folding devices 19 and 20 could comprise parts in movement.
[0024] According to what is illustrated in Figures 8, 9 and 10, the transverse folder 18 comprises a folding element 21 which is configured to spread the two longitudinal flaps 8 and 9 apart, namely to fold the two longitudinal flaps 8 and 9 in opposite directions (folding each one outwards by an angle between 30° and 90°) so as to move them away from each other (as is illustrated in Figure 18). In other words, the folding element 21 is configured to fold the two longitudinal flaps 8 and 9 in opposite directions towards the outside of the group 2 of cigarettes. The spreading apart of the two longitudinal flaps 8 and 9 caused by the action of the folding element 21 involves an inward folding (namely towards each other) of the two transverse flaps 7 (as is illustrated in Figure 18). Furthermore, the transverse folder 18 comprises a folding element 22 which is configured to fold the two transverse flaps 7 (already pushed inwards by the folding element 21) against the group 2 of cigarettes (as is illustrated in Figure 19).
[0025] The folding element 21 is movable only linearly (namely translates) along a straight folding direction D perpendicular to the folding path P2. In particular, an actuator device 23 is provided configured to move (translate) the folding element 21 back and forth along the folding direction D. The folding element 21 has a body 24 which has, at the two opposite ends, two inclined planes 25, each of which comes into contact with a respective longitudinal flap 8 or 9 and pushes the respective longitudinal flap 8 or 9 outwards; the two inclined planes 25 are arranged on opposite sides with respect to the wrapping path P2.
[0026] The folding element 22 is movable only linearly (namely translates) along the straight folding direction D perpendicular to the folding path P2. In particular, an actuator device 26 is provided configured to move (translate) the folding element 22 back and forth along the folding direction D. Namely the two folding elements 21 and 22 both move back and forth in the same folding direction D independently of each other; in fact, in use, first the folding element 21 carries out a (an active) forward stroke of its own to spread the two longitudinal flaps 8 and 9 apart and then only subsequently the folding element 21 carries out a (an active) forward stroke of its own to fold the two transverse flaps 7 (already pushed inwards by the folding element 21) against the group 2 of cigarettes. Once the folding of the two transverse flaps 7 against the group 2 of cigarettes is completed, both folding elements 21 and 22 carry out together a return stroke to move away from the wrap 1 and thus return to a start position ready for a subsequent work cycle.
[0027] The folding element 22 has two bodies 27 which are arranged at the two opposite ends of the folding element 22 (namely are separate from each other) and are shaped to press the respective transverse flaps 7 against the group 2 of cigarettes.
[0028] According to what is illustrated in Figures 9 and 10, the folding elements 21 and 22 are shaped to be complementary to each other and, thus, be able to arrange the bodies 24 and 27 side by side without mutual interferences; in this manner, the folding elements 21 and 22 can translate along the folding direction D independently of each other. In particular, the folding element 21 comprises a support 28 which is oriented perpendicular to the folding direction D, is directly connected to the actuator device 23 and supports, in a projecting manner, the body 24 which has a vertical extension (perpendicular to the wrapping path P2 and to the folding direction D which are horizontal) which is greater than (double) the support 28. Similarly, the folding element 22 comprises a support 29 which is oriented perpendicular to the folding direction D, is directly connected to the actuator device 26 and supports, in a projecting manner, the bodies 27 which have a vertical extension (perpendicular to the wrapping path P2 and to the folding direction D which are horizontal) which is greater than (double) the support 29. The two supports 28 and 29 are arranged vertically staggered, namely they are arranged one above the other.
[0029] In summary, the bodies 24 and 27 are tall (namely more vertically extended) and narrow (namely less horizontally extended and thus parallel to the wrapping path P2) so as to be arranged side by side, whereas the supports 28 and 29 are short (namely less vertically extended) and wide (namely more horizontally extended and thus parallel to the wrapping path P2) so as to be arranged overlapping each other.
[0030] According to a preferred embodiment better illustrated in Figure 11, each pocket 15 has two inclined striker surfaces 30 (namely inclined planes) opposite each other which originate from the edges of the respective cavity 16 and have (reproduce) the same inclination of the inclined planes 25 of the body 24 of the folding element 21 so that, in use, the inclined planes 25 press the longitudinal flaps 8 and 9 against the striker surfaces 30 of the corresponding pocket 15.
[0031] Between the transverse folder 18 and the subsequent longitudinal folders 19 and 20 (which are seamlessly contiguous with respect to each other), elements could be provided that keep the transverse flaps 7 (previously folded by the transverse folder 18) pressed against the respective group 2 of cigarettes so as to avoid elastic returns that move away (lift) the transverse flaps 7 from the respective group 2 of cigarettes and can thus cause the folds to be stuck in the longitudinal folders 19 and 20; however, the occurred pressing of the longitudinal flaps 8 and 9 against the striker surfaces 30 of the pockets 15 should already on its own avoid any risk of reopening of the folding of the transverse flaps 7 (namely the risk that by elastic return the transverse flaps 7 move away from the respective group 2 of cigarettes).
[0032] According to a possible embodiment the striker surfaces 30 of the pockets 15 and / or the body 24 of the folding element 21 are heated so that the pressing of the longitudinal flaps 8 and 9 against the striker surfaces 30 occurs hot (typically when the wrapping sheet 3 at least partially consists of heat-sealable materials).
[0033] In the embodiment illustrated in Figure 7, the wrapping unit 10 operates on one single line and thus manufactures one single wrap 1 at a time, namely the wrapping conveyors 11 and 12 have one single wrapping line along which one single wrap 1 being formed is advanced at a time; consequently, the transverse folder 18 folds the transverse flaps 7 of one single wrap 1 at a time (as is illustrated in Figures 8-12).
[0034] According to a different embodiment (as, for example, described in patent applications EP3925896A1 and EP4257496A1), the wrapping unit 10 operates on a double line and thus manufactures two wraps 1 at a time, namely the wrapping conveyors 11 and 12 have two side-by-side wrapping lines (namely a double wrapping line) along which two side-by-side wraps 1 being formed are advanced at a time; namely, the wrapping unit 10 is configured to arrange two wraps 1 side by side which are formed together (namely two wrapping sheets 3 are folded together around two groups 2 of cigarettes) and preferably (but not necessarily) are subsequently inserted in a same pack for cigarettes (called in jargon "double bundle"). Consequently, also the transverse folder 18 folds the transverse flaps 7 of two side-by-side wraps 1 at a time (as is illustrated in Figures 13-16). According to what is illustrated in Figures 13-16, the cavity 16 of each pocket has a width which is increased so as to contain two wraps 1 side by side, the folding element 21 has two bodies 24 spaced apart (to simultaneously operate on two wraps 1 side by side) and the folding element 22 has four bodies 27 spaced apart (to simultaneously operate on two wraps 1 side by side).
[0035] Figures 17, 18 and 19 illustrate the folding of two side-by-side wrapping sheets 3 around two side-by-side groups 2 of cigarettes: Figure 17 shows (from two different angulations) the two wrapping sheets 3 having the end open and coming from the wrapping conveyor 13 (namely in the shape illustrated also in Figure 4), Figure 18 shows (from two different angulations) the two wrapping sheets 3 after the action of the folding element 21 provided with the bodies 24 (it should be noted how the action of the folding element 21 by spreading the longitudinal flaps 8 and 9 apart determines an inward folding of the two transverse flaps 7, namely towards each other), and Figure 19 shows (from two different angulations) the two wrapping sheets 3 after the action of the folding element 22 provided with the bodies 27 (it should be noted how the action of the folding element 22 presses the two transverse flaps 7 against the group 2 of cigarettes).
[0036] In the embodiment illustrated in the accompanying figures, the transverse folder 18 operates on a wrapping sheet 3 having one single open end delimited by two transverse flaps 7 and by two longitudinal flaps 8 and 9; according to a different embodiment not illustrated, a pair of transverse folders 18 operates on the opposite sides of a wrapping sheet 3 having two opposite open ends each delimited by two transverse flaps and by two longitudinal flaps.
[0037] The embodiment illustrated in the accompanying figures refers to the manufacturing of a pack for cigarettes, but the present invention is also applicable without substantial modifications to the manufacturing of any other type of pack for smoking articles (for example a pack for cigars, a pack for electronic cigarettes of the liquid vaporization type, a pack for next generation heat-not-burn cigarettes...).
[0038] The embodiments described herein can be combined with one another.
[0039] The wrapping unit 10 described above has numerous advantages.
[0040] Firstly, the wrapping unit 10 allows manufacturing a high-quality pack 1 for cigarettes even operating at a high production speed (measured as packs 1 for cigarettes produced in the time unit). In particular, the transverse folder 18 makes it possible (unlike the known methods currently used) to press the transverse flaps 8 and 9 against the striker surfaces 30 of the corresponding pocket 15 (particularly advantageous in the case of thicker and / or tougher materials) and such pressing allows obtaining precise and very well-defined folds.
[0041] Furthermore, the wrapping unit 10 described above is particularly simple as it almost exclusively uses fixed folding profiles and has only the two movable folding elements 21 and 22 which have an extremely simple movement (namely only back and forth along the straight folding direction D).
[0042] The wrapping unit 10 described above is advantageously applied also operating on one single line, but is particularly advantageous operating on a double line in which the head folds (namely the folds of the flaps 7, 8 and 9 of each wrap 1) must be manufactured when two wraps 1 are already side by side and close (as is illustrated in Figures 17, 18 and 19): in this situation, the transverse flaps 7 that are located in-between are in mutual contact and leave no space for the entrance between them of a traditional folder which can fold the transverse flaps 7 against the respective groups 2 of cigarettes, whereas the transverse folder 18 operates without any problems even if the transverse flaps 7 which are located in-between are in mutual contact (as it obtains an inward fold of the transverse flaps 7 spreading the longitudinal flaps 8 and 9 apart). On the other hand, keeping separate the two wraps 1 up to the moment of performing the folds of the transverse flaps 7, or even separating again the wraps 1 when they are already joined, requires additional paths and movements with respect to the movements necessary for operating on one single line and this at the detriment of costs and arrangement of the wrapping unit 10, besides of the efficiency due to the increased number of passages to which the wraps 1 being formed are subjected. In other words, the transverse folder 18 allows folding the open heads of the wraps 1 (namely allows folding the flaps 7, 8 and 9 of each wrap 1) without any need to move two side-by-side wraps 1 being formed away from each other.LIST OF THE REFERENCE NUMERALS OF THE FIGURES
[0043] 1wrap 2group of cigarettes 3wrapping sheet 4transverse flap 5longitudinal flaps 6longitudinal flaps 7transverse flaps 8longitudinal flaps 9longitudinal flaps 10wrapping unit 11wrapping conveyor 12feeding device 13folding device 14wrapping conveyor 15pockets 16cavity 17folding device 18transverse folder 19longitudinal folder 20longitudinal folder 21folding element 22folding element 23actuator device 24body 25inclined planes 26actuator device 27body 28support 29support 30striker surfaces P1wrapping path P2wrapping path S1transfer station S2feeding station S3transfer station S4transfer station Dfolding direction
Claims
1. A wrapping unit (10) to manufacture a wrap (1) around a group (2) of smoking articles and comprising: a first folding device (13) configured to fold a wrapping sheet (3) around the group (2) of smoking articles, so as to cause the wrapping sheet (3) to gain a tubular shape having at least one open end delimited by two transverse flaps (7) and two longitudinal flaps (8, 9); and a second folding device (17) configured to initially fold the two transverse flaps (7) against the group (2) of smoking articles, to subsequently fold a first longitudinal flap (8) against the group (2) of smoking articles and on top of the previously folded transverse flaps (7) and to finally fold a second longitudinal flap (9) against the group (2) of smoking articles and on top of the transverse flaps (7) and the first longitudinal flap (8), which were previously folded; the wrapping unit (10) is characterized in that the second folding device (17) comprises a first folding element (21), which is configured to simultaneously spread both two longitudinal flaps (8, 9) apart before folding the two transverse flaps (7) against the group (2) of smoking articles.
2. The wrapping unit (10) according to claim 1, wherein the first folding element (21) is configured to fold the two longitudinal flaps (8, 9) towards the outside of the group (2) of smoking articles and in opposite directions so as to move them away from each other and the spreading apart of the two longitudinal flaps (8, 9) caused by the action of the first folding element (21) involves an inward folding of the two transverse flaps (7), namely towards each other.
3. The wrapping unit (10) according to claim 1 or 2, wherein: the first folding element (21) is movable only linearly along a straight folding direction (D); and the second folding device (17) comprises a first actuator device (23) configured to move the first folding element (21) back and forth along the folding direction (D).
4. The wrapping unit (10) according to claim 1, 2 or 3, wherein the first folding element (21) has a first body (24), which has, at the two opposite ends, two inclined planes (25), each of which comes into contact with a respective longitudinal flap (8, 9) and pushes the respective longitudinal flap (8, 9) outwards.
5. The wrapping unit (10) according to one of the claims from 1 to 4, wherein the second folding device (17) comprises a second folding element (22), which is configured to fold the two transverse flaps (7) against the group (2) of smoking articles.
6. The wrapping unit (10) according to claim 5, wherein: the second folding element (22) is movable only linearly along a straight folding direction (D); and the second folding device (17) comprises a second actuator device (26) configured to move the second folding element (22) back and forth along the folding direction (D).
7. The wrapping unit (10) according to claim 5 or 6, wherein the second folding element (22) has two second bodies (27), which are arranged at the two opposite ends of the second folding element (22) and are shaped to press the respective transverse flaps (7) against the group (2) of smoking articles.
8. The wrapping unit (10) according to claim 5, 6 or 7, wherein: the first folding element (21) is movable only linearly along a straight folding direction (D); and the second folding element (22) is movable only linearly along the straight folding direction (D) independently of the first folding element (21).
9. The wrapping unit (10) according to one of the claims from 5 to 8, wherein: the first folding element (21) has a first body (24), which has, at the two opposite ends, two inclined planes (25), each of which comes into contact with a respective longitudinal flap (8, 9) and pushes the respective longitudinal flap (8, 9) outwards; the second folding element (22) has two second bodies (27), which are arranged at the two opposite ends of the second folding element (22) and are shaped to press the respective transverse flaps (7) against the group (2) of smoking articles; and the folding elements (21, 22) are shaped to be complementary to each other and, thus, be able to arrange the respective bodies (24, 27) side by side without mutual interferences.
10. The wrapping unit (10) according to claim 9, wherein: the first folding element (21) comprises a first support (28), which is oriented perpendicular to a horizontal folding direction (D) and supports, in a projecting manner, the first body (24), which has a greater vertical extension than the first support (28); the second folding element (22) comprises a second support (29), which is oriented perpendicular to the horizontal folding direction (D) and supports, in a projecting manner, the second bodies (27), which have a greater vertical extension than the second support (29); and the two supports (28, 29) are vertically staggered, namely they are arranged one above the other.
11. The wrapping unit (10) according to one of the claims from 1 to 10 and comprising a wrapping conveyor (14) configured to move, along a wrapping path (P2) perpendicular to a folding direction (D), a pocket (15) provided with a cavity (16) shaped to house the wrapping (1) being formed.
12. The wrapping unit (10) according to claim 11, wherein: the first folding element (21) has a first body (24) which has, at the two opposite ends, two inclined planes (25), each of which comes into contact with a respective longitudinal flap (8, 9) and pushes the respective longitudinal flap (8, 9) outwards; and the pocket (15) has two inclined and opposite striker surfaces (30), which originate from the edges of the cavity (16) and against which the two inclined planes (25) of the first folding element (21) press the two longitudinal flaps (8, 9).
13. The wrapping unit (10) according to claim 12, wherein the striker surfaces (30) of the pocket (15) and / or the first body (24) of the first folding element (21) are heated.
14. The wrapping unit (10) according to one of the claims from 1 to 13, wherein: the wrapping unit (10) is configured to arrange two wraps (1) side by side; and the first folding element (21) is configured to simultaneously fold the longitudinal flaps (8, 9) of two wraps (1) side by side.
15. A wrapping method to manufacture a wrap (1) around a group (2) of smoking articles and comprising the steps of: folding a wrapping sheet (3) around the group (2) of smoking articles, so as to cause the wrapping sheet (3) to gain a tubular shape having at least one open end delimited by two transverse flaps (7) and two longitudinal flaps (8, 9); initially folding the two transverse flaps (7) against the group (2) of smoking articles; subsequently folding a first longitudinal flap (8) against the group (2) of smoking articles and on top of the previously folded transverse flaps (7); and finally folding a second longitudinal flap (9) against the group (2) of smoking articles and on top of the transverse flaps (7) and the first longitudinal flap (8), which were previously folded; the wrapping method is characterized in that it comprises the step of simultaneously spreading both two longitudinal flaps (8, 9) apart before folding the two transverse flaps (7) against the group (2) of smoking articles.