EP4079648B1

EP4079648B1 - A grouping unit and method to form a group consisting of two wraps, each containing a group of smoking articles

Info

Publication number: EP4079648B1
Application number: EP22169305.4A
Authority: EP
Inventors: Mattia MECCAGNI; Franco FALCINELLI; Massimo Benassi; Michele Squarzoni; Giuliano Gamberini
Original assignee: GD SpA
Current assignee: GD SpA
Priority date: 2021-04-22
Filing date: 2022-04-21
Publication date: 2024-04-10
Anticipated expiration: 2042-04-21
Also published as: EP4079648A1; IT202100010193A1

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This Patent Application claims priority from Italian/ European Patent Application No. 102021000010193 filed on April 22, 2021 .

TECHNICAL FIELD

The present invention relates to a grouping unit and a grouping method to form a group consisting of two wraps, each containing a group of smoking articles.
The present invention finds advantageous application in the creation of a rigid packet of cigarettes with a "twin"-type hinged lid and containing two twin and side by side wraps, to which the following discussion will make explicit reference without losing generality.

PRIOR ART

A packet of cigarettes commercially called "twin" has been known for several years, and it comprises a rigid outer container that houses two identical groups of cigarettes (i.e. "twins," from which the commercial name of the packet of cigarettes), which are arranged side by side and are wrapped in corresponding wrapping sheets.
Patent EP3362365B1 describes a packing machine to produce a "twin" packet of cigarettes comprising: a forming unit in which the groups of cigarettes are formed in succession, a first wrapping unit provided with horizontal axis wheels in which a wrapping sheet is folded around each group of cigarettes to form a corresponding wrap, a grouping unit (coupling) provided with a wheel in which the wraps are grouped (coupled) in pairs to form the contents of the packets of cigarettes, and a second wrapping unit provided with horizontal axis wheels in which a collar and a rough piece are folded around each pair of wraps to form an external container.
Patent US4258528A describes a packing machine to produce a "twin" packet of cigarettes comprising: a forming unit in which the groups of cigarettes are formed in succession, a first wrapping unit provided with linear conveyors in which a wrapping sheet is folded around each group of cigarettes to form a corresponding wrap, a grouping unit (coupling) in which the internal wraps are grouped (coupled) in pairs to form the contents of the packets of cigarettes, and a second wrapping unit provided with a vertical axis wheel in which a collar and a rough piece are folded around each pair of wraps to form an external container.
Patent application EP3056005A1 describes a packing machine for producing a "twin" packet of cigarettes comprising: a forming unit in which the groups of cigarettes are formed in succession, a first wrapping unit provided with linear conveyors in which a wrapping sheet is folded around each group of cigarettes to form a corresponding wrapping, a grouping unit (coupling) in which internal wraps are grouped (coupled) in pairs to form the contents of the packets of cigarettes, and a second wrapping unit provided with a horizontal axis wheel in which a collar and a rough piece are folded around each pair of wraps to form an external container.
Patent application EP3070005A1 represents the closest state of the art and describes a wrapping method for making packets of smoking articles, each containing two distinct groups of smoking articles.
When the first wrapping unit is provided with linear conveyors, the known grouping (coupling) units have a complex structure and above all require carrying out rather long adjustments in the event of a change in the format (i.e. the dimensions) of the packet of cigarettes to be produced.

DESCRIPTION OF THE INVENTION

The object of the present invention is to provide a grouping unit and a grouping method to form a group consisting of two wraps, each containing a group of smoking articles, which grouping unit and method are simple to implement, allow to operate at a high production rate (measured as packets of cigarettes produced in the unit of time), and allow to quickly perform the format change operations.
In accordance with the present invention, a grouping unit and a grouping method are provided to form a group consisting of two wraps, each containing a group of smoking articles, as claimed in the appended claims.
The claims describe embodiments of the present invention and form integral part of the present description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described with reference to the accompanying drawings, illustrating a non-limiting implementation example:

figure 1 is a front perspective view and in a closed configuration of a rigid cigarette packet;
figure 2 is a rear perspective view of the cigarette packet of figure 1 in a closed configuration;
figure 3 is a front perspective view of the packet of cigarettes of figure 1 in an open configuration;
figure 4 is a front perspective view of a packet wrap of figure 1;
figure 5 is a perspective view of a group of cigarettes contained in the wrap of figure 4;
figure 6 is a plan view of a wrapping sheet used to make the wrap of figure 4;
figure 7 is a plan view of a collar of the packet of cigarettes of figure 1;
figure 8 is a plan view of a rough piece used to make an outer container provided with a hinged lid of the packet of cigarettes of figure 1;
figure 9 is a perspective, schematic view with some parts removed for clarity of a packing machine that produces the packet of cigarettes of figure 1 and is made in accordance with the present invention;
figure 10 is a plan and schematic view of part of the packing machine of figure 9;
figure 11 is a side and schematic view of part of the packing machine of figure 9; and
figures 12-20 schematically illustrate the operation of a grouping unit of the packing machine of figure 9.

PREFERRED EMBODIMENTS OF THE INVENTION

In figures 1, 2 and 3 with the number 1 a rigid "twin" packet of cigarettes is indicated as a whole. The packet 1 of cigarettes comprises an outer container 2 made of rigid and cup-shaped cardboard or board and a pair of wraps 3 (one of which is better illustrated in figure 4) housed side by side inside the container 2.
The outer container 2 has an open upper end and is provided with a lid 4, which is cup-shaped and is hinged to the outer container 2 along a hinge 5 (illustrated in figure 2) to rotate, with respect to the outer container 2, between an open position (illustrated in figure 3) and a closed position (illustrated in figures 1 and 2) of the open upper end. The outer container 2 has a substantially rectangular parallelepiped shape oriented according to a predominantly vertical development direction, is cup-shaped, and has an open upper end, a lower wall 6 opposite the open upper end, a front wall 7 and a rear wall 8 (in which the hinge 5 is obtained) parallel and opposite to each other, and two side walls 9 parallel and opposite to each other.
The lid 4 has a substantially rectangular parallelepiped shape, is cup-shaped, and has an open lower end (facing the open upper end of the outer container 2 when the lid 4 is in the closed position), an upper wall 10 (which is parallel and opposite the lower wall 6 of the outer container 2 when the lid 4 is in the closed position), a front wall 11 (which is parallel and aligned with the front wall 7 of the outer container 2 when the lid 4 is in the closed position), a rear wall 12 (which is parallel and aligned with the rear wall 8 of the outer container 2 when the lid 4 is in the closed position and is hinged to the rear wall 8 of the outer container 2 along the hinge 5), and two side walls 13 parallel and opposite to each other (which are parallel and aligned, in particular coplanar and adjacent, to the side walls 9 of the outer container 2 when the lid 4 is in the closed position).
Each wrap 3 encloses a group 14 of cigarettes (illustrated in figure 5) of parallelepiped shape. Also, each wrap 3 has a removable portion 15 on the top and front that is separated from the rest of the wrap 3 by a pre-weakened tearable line 16; at the first opening of the packet 1 of cigarettes the user grasps and tears the removable portion 15 to access the underlying cigarettes of the group 14 of cigarettes.
As illustrated in figures 3 and 7, the packet 1 of cigarettes further comprises a rigid collar 17, which is connected (by gluing) in a "U"-folded way inside the outer container 2 to partially protrude outside the open upper end of the outer container 2 and engage a corresponding inner surface of the lid 4 when the lid 4 is arranged in the closed position. The collar 17 comprises a front wall 18, which is connected to the front wall 7 of the container 2 and is arranged in contact with the front wall 11 of the lid 4 when the lid 4 is in the closed position, and two side walls 19, which are connected to the side walls 9 of the container 2 and are arranged in contact with the side walls 13 of the lid 4 when the lid 4 is in the closed position. According to the embodiment illustrated in the appended figures, the front wall 18 of the collar 17 is provided with a pair of side protruding claws 20 for interferently engaging the side walls 13 of the lid 4 when the lid 4 is in the closed position so as to keep the lid 4 in the closed position. According to a different embodiment not illustrated, the front wall 18 of the collar 17 is free of claws 20.
As illustrated in figure 6, each wrap 3 is made by folding around the group 14 of cigarettes a wrapping sheet 21 provided on one side of the tearable line 16 delimiting the removable portion 15.
As illustrated in figure 8, the outer container 2 and the lid 4 are made by folding a rough piece 28 of a conventional type.
In figure 9, number 29 indicates as a whole a packing machine which is designed to make the packet 1 of cigarettes described above and works with intermittent motion (i.e., a motion that provides for a cyclic alternation of motion phases and rest phases).
The packing machine 29 comprises a frame 30 which rests on the ground by means of a plurality of feet (not illustrated) and is formed by joining two bodies 31 and 32 arranged side by side; in particular, the body 31 has a front wall and a side wall on which the operating members (partially described below) are arranged while the body 32 has (only) a front wall on which all the operating members (partially described below) are arranged. The packing machine 29 comprises a forming unit A in which the groups 14 of cigarettes are formed in succession, a wrapping unit B in which a respective wrapping sheet 21 is wound around each group 2 of cigarettes to make a wrap 3, a grouping unit C (coupling) in which the wraps 3 are grouped (coupled) in pairs to form the contents of the packets 1 of cigarettes, and a wrapping unit D in which a collar 17 and a rough piece 28 are wound around each pair of grouped (coupled) wraps 3 to make an external container 2 provided with a lid 4.
The forming unit A of groups 14 of cigarettes comprises a hopper 33 provided with three outlet mouths 34 for simultaneously feeding three groups 14 of cigarettes to three respective pockets 35 of a forming conveyor 36 supporting a plurality of pockets 35. The forming conveyor 36 comprises an annular-shaped conveyor belt, which is wound around two end pulleys (one of which is motorized), supports the pockets 35 and moves step by step to cyclically move the pockets 35 along a formation path P1 (illustrated in figure 10). As better illustrated in figure 10, the formation path P1 develops between an input station S1 in which each group 14 of cigarettes is extracted from an outlet mouth 34 of the hopper 33 and enters a corresponding pocket 35 and a transfer station S2 in which each group 14 of cigarettes is extracted from the corresponding pocket 35.
As illustrated in figure 10, the wrapping unit B comprises a wrapping conveyor 37 designed to move forward a single group 14 of cigarettes (extracted from a pocket 35 of the forming conveyor 36 in the transfer station S2) along a straight and horizontal wrapping path P2. In particular, the wrapping path P2 extends from the transfer station S2 in which the wrapping conveyor 37 extracts a group 14 of cigarettes at a time from the corresponding pocket 35 of the forming conveyor 36, passes through a feeding station S3 in which the group 14 of cigarettes is coupled to a corresponding wrapping sheet 21 (received in a receiving station S4) that folds in a "U" shape around the group 14 of cigarettes, and ends in a transfer station S5 in which the wrap 3 (formed by a wrapping sheet 21 folded around the group 14 of cigarettes) leaves the wrapping conveyor 37 (to enter the grouping unit C).
As illustrated in figure 11, the wrapping conveyor 37 comprises an annular-shaped conveyor belt 38, which is wound around two end pulleys (one of which is motorized) and supports a plurality of pairs of pushers 39, each of which is connected to the conveyor belt 38 by a support column (narrow, or narrower than the pusher 39) and is designed to engage a rear wall of a corresponding group 14 of cigarettes to push the group 14 of cigarettes along the wrapping path P2. In other words, the wrapping conveyor 37 comprises a horizontal channel, which is delimited at least on the lower side and laterally (preferably also on the upper side in its initial part), is arranged along the wrapping path P2, and contains the group 14 of cigarettes while the group 14 of cigarettes moves forward along the wrapping path P2 pushed by a corresponding pusher 39 from the back.
Along the wrapping path P2 (and therefore at the wrapping conveyor 37) there is a feeding station S3 in which each wrapping sheet 21 is arranged to be intercepted by a corresponding group 14 of cigarettes around which the wrapping sheet 21 folds in a "U" shape; in other words, each group 14 of cigarettes moving forward along the wrapping path P2 intercepts a corresponding wrapping sheet 21 arranged in the feeding station S3, determining the "U" shape folding of the wrapping sheet 21.
The packing machine 29 comprises a feeding device 40 that cyclically feeds the wrapping sheets 21 in the feeding station S3, i.e. arranges each wrapping sheet 21 in the feeding station S3 in such a way that the wrapping sheet 21 is intercepted by a corresponding group 14 of cigarettes that moves forward along the wrapping path P2. As illustrated in figure 9, the feeding device 40 comprises an unwinding station in which a wrapping material web 41 is unwound by a reel 42 and is moved forward (passing next to the hopper 33) towards a cutting member 43 of known type which is arranged above the receiving station S4 (and therefore also above the feeding station S3) and cyclically performs a cross cut of the wrapping material web 41 to separate the wrapping sheets 21 from the wrapping material web 41. The feeding device 40 could also comprise a processing member (e.g., an embosser) which is arranged between the unwinding station and the cutting member 43 and performs a processing (e.g., an embossing) of the wrapping material web 41.
As illustrated in figure 10, the wrapping unit B comprises a folding device 44 that is arranged along the wrapping path P2 downstream of the feeding station S3 and is adapted to fold two open lateral ends of each sheet 21 of wrap folded in a "U" shape around a corresponding group 14 of cigarettes to form a tubular wrap having an open rear end. Preferably, the folding device 44 comprises only folding profiles (i.e. folding spiral means) which are fixed (i.e. completely free of moving parts) and are arranged on opposite sides of the wrapping path P2.
As illustrated in figure 10, the wrapping unit B comprises a folding device 45 which is arranged along the wrapping path P2 downstream of the folding devices 44 and is designed to complete the folding of each wrapping sheet 21 around the corresponding group 14 of cigarettes (and therefore terminate the making of the wrap 3) to close the open rear end (i.e. previously left open by the folding device 44).
It is important to note that the wrapping unit B operates on a single line, i.e. a single group 14 of cigarettes at a time is moved forward along the wrapping path P2 and becomes part of a single wrap 3.
The wrapping path P2 starts at the transfer station S2 (where the groups 14 of cigarettes individually enter the wrapping conveyor 37) and terminates at the transfer station S5 (where the wrappers 3 individually leave the wrapping conveyor 37 to enter the grouping unit C). As illustrated in figure 9, the packing machine 29 comprises a transfer conveyor 46 that receives the wraps 3 from the grouping unit C (as better described below) and moves forward the wraps 3 along a straight transfer path P3 and perpendicular to the wrapping path P2 to a transfer station S6 (where the wraps 3 leave the transfer conveyor 46). The transfer conveyor 46 comprises an annular-shaped conveyor belt, which is wound around two end pulleys (one of which is motorized), supports a plurality of pockets 47 each designed to house a corresponding pair of side by side (grouped) wraps 3, and moves step by step to cyclically move the pockets 47 along the transfer path P3 from the grouping unit C to the transfer station S6.
As mentioned above, the grouping unit C is arranged between the wrapping conveyor 37 and the transfer conveyor 46, cyclically receives single wraps 3 from the wrapping conveyor 37 and in the single wrap transfer station S5, and hands over single wraps 3 to the pockets 47 of the transfer conveyor 46 in such a way as to group a pair of wraps 3 in each pocket 47; that is, the wrapping conveyor 37 moves forward single wraps 3 along the wrapping path P2 while the transfer conveyor 46 moves forward pairs (or groups of two) of wraps 3 along the transferring path P3 . Consequently, the wrapping conveyor 37 has a speed of travel which is twice that of the transfer conveyor 46.
As illustrated in figure 12, the grouping unit C comprises two (and only two) pockets 48 and 49, each designed to house a respective wrap 3. Also, the grouping unit C comprises two output stations S8 and S9 and an input station S7 arranged between the two output stations S8 and S9 (and arranged at the transfer station S5).
The grouping unit C comprises an insertion device 50 (schematically illustrated in figure 12) which is adapted to insert a single wrap 3 received by the wrapping conveyor 37 alternatively in the pocket 48 or in the pocket 49 which stand one or the other (i.e. in turn) in the input station S7 (as illustrated in figures 12-14 and 16-19); in particular in figures 12-14 the pocket 48 in the input station S7 is illustrated while in figures 16-19 the pocket 49 in the input station S7 is illustrated.
The grouping unit C comprises an extraction device 53 (schematically illustrated in figure 12) which is designed to extract a single wrap from the pocket 48 which stands in the output station S8 (as illustrated in figures 16-19) or, alternatively, is designed to extract a single wrap from the pocket 49 standing in the output station S9 (as illustrated in figures 12-14) which is opposite the output station S8 with respect to the input station S7.
The grouping unit C comprises a moving device 52 (schematically illustrated in figure 12) which is adapted to move the pocket 48 along a direction D 1 of horizontal movement between the input station S7 and the output station S8 (and vice versa) and simultaneously is adapted to move the pocket 19 between the output station S9 and the input station S7 (and vice versa); obviously, when the pocket 48 is in the input station S7 (as illustrated in figures 12-14) the pocket 19 is in the output station S9 while when the pocket 48 is in the output station S8 (as illustrated in figures 16-19) the pocket 49 is in the input station S7.
As is well illustrated in figure 12, the input station S7 and the output stations S8 and S9 are aligned to one another along the moving direction D1 and, as mentioned above, the input station S7 stands between the two output stations S8 and S9. As is well illustrated in figure 12, the two pockets 48 and 49 are aligned to one another along the moving direction D1; additionally, the pocket 48 is arranged on one side while the pocket 49 is arranged on the opposite side.
As illustrated in figure 12, the moving device 52 comprises a rigid support element 53 (essentially a bar arranged horizontally along the moving direction D1) which is slidingly mounted axially to move alternately back and forth along the moving direction D1; the support element 53 supports the pockets 49 and 50, i.e. the pockets 49 and 50 are rigidly fixed to the rigid support element 53 and thus move together with the rigid support element 53 (i.e. the two pockets 49 and 50 always move in a synchronous manner with each other). Thus, the two pockets 49 and 50 always have the same law of motion (imposed by the support element 53).
The moving device 52 moves the support element 53 in opposite directions along the moving direction D1 and makes the support element 53 always travelling the same stroke T (illustrated in figures 14-16 and 19-20) in alternatively opposite directions. That is, the moving device 52 moves the support element 53 along the moving direction D1 alternatively in both directions.
Generally, the moving device 52 comprises a single common electric motor that imparts, by means of a mechanical transmission that transforms the rotary motion into a linear motion, the alternative movement to the support element 53. When a format change operation requires to change the stroke T of the support element 53 (i.e. of the pockets 48 and 49), it is only sufficient to intervene by software on the control of the electric motor of the moving device 52 without any replacement of physical components.
As illustrated in figure 12, the insertion device 50 comprises a single pusher 54 which is arranged at the input station S7 and is movable perpendicularly to the moving direction D1 along a main and horizontal direction D2; additionally, the extraction device 53 comprises two pushers 55 which are arranged at the output stations S8 and S9 and are movable perpendicularly to the moving direction D1 along the main and horizontal direction D2.
As illustrated in figure 12, the grouping unit C comprises a common and rigid support element 56 supporting both the pusher 54 of the input station S7 and the two pushers 55 of the output stations S8 and S9; in this way all the pushers 54 and 55 always move together with the same law of motion. Finally, the grouping unit C comprises a moving device 57 (schematically illustrated in figure 12 and preferably using an articulated quadrilateral) which alternatively moves the support element 56 both along the main and horizontal direction D2, which is perpendicular to the moving direction D1, and along a secondary vertical direction D3 (illustrated in figure 11), which is perpendicular to the main direction D2 and perpendicular to the moving direction D1. In particular, the moving device 57 causes the support element 56 (and therefore the pusher elements 54 and 55 carried by the support element 56) to have a work stroke (in which the pusher elements 54 and 55 push the respective wraps 3) by moving the support element 56 only along the main direction D2 and causes the support element 56 to have a return stroke (in which the pusher elements 54 and 55 do not touch any wraps 3) by moving the support element 56 in the secondary direction D3 and downwards, then in the main direction D2 with a direction that is opposite to the work stroke, and finally in the secondary direction D3 and upwards. In other words, in the return stroke the support element 56 (therefore the pushers 54 and 55 carried by the support element 56) lowers so as to not interfere with the wraps 3.
According to a preferred embodiment, the pockets 48 and 49 have a slit on the lower side through which a thin shaft connecting the pushers 54 and 55 to the rest of the support element 56 passes.
According to a possible embodiment, the movement imparted on the support element 56 by the moving device 57 could also be used to complete the folding of the wraps 3; that is, the support element 56 is also connected to the folding elements which, as a result of the movement of the support element 56, perform final folding operations on the wraps 3.
With reference to figures 12-20, the operation of the grouping unit C is described below. Initially and as illustrated in figure 12, the pocket 48 is stationary and stands in the input station S7 in alignment with the wrapping conveyor 37 and therefore ready to receive a single wrap 3 which comes from the wrapping conveyor 37; at the same time, the pocket 49 is stationary and is in the output station S9 in alignment with a pocket 47 of the transfer conveyor 46 and therefore ready to transfer a single wrap 3 to the pocket 47.
At this point, and as illustrated in figures 13 and 14, while the pockets 48 and 49 are stationary, the pushers 54 and 55 perform their working stroke: the pusher 54 inserts a single wrap 3 in the pocket 48 which is in the input station S7 and simultaneously the pusher 55 which is in the output station S9 extracts a single wrap 3 from the pocket 49 which is in the output station S9 and inserts the single wrap 3 into a pocket 47 of the transfer conveyor 46. In this phase, also the pusher 55 of the output station S8 performs its own work stroke which is, however, loadless as there is no pocket 48 in the output station S8.
Subsequently and as illustrated in figures 14, 15 and 16, the pockets 48 and 49 move in the same direction along the moving direction D1 travelling the stroke T in one direction to move the pocket 48 (containing a wrap 3) from the input station S7 to the output station S8 and to simultaneously move the pocket 49 (empty) from the output station S9 to the input station S7.
As illustrated in figures 16 e 17, at the end of the movement, the pocket 49 is stationary and stands in the input station S7 in alignment with the wrapping conveyor 37 and therefore ready to receive a single wrap 3 which comes from the wrapping conveyor 37; at the same time, the pocket 48 is stationary and is in the output station S8 in alignment with a pocket 47 of the transfer conveyor 46 and therefore ready to transfer a single wrap 3 to the pocket 47.
At this point, and as illustrated in figures 18 and 19, while the pocket 48 is stationary, the pushers 54 and 55 perform their working stroke: the pusher 54 inserts a single wrap 3 in the pocket 49 which is in the input station S7 and simultaneously the pusher 55 which is in the output station S8 extracts a single wrap 3 from the pocket 48 which is in the output station S8 and inserts the single wrap 3 into a pocket 47 of the transfer conveyor 46. In this phase, also the pusher 55 of the output station S9 performs its own work stroke which is, however, useless as there is no pocket 49 in the output station S8.
Subsequently and as illustrated in figures 19 and 20, the pockets 48 and 49 move in the same direction along the moving direction D1 making the travel T in a direction opposite to the one before to move the pocket 49 (containing a wrap 3) from the input station S7 to the output station S9 and to simultaneously move the pocket 48 (empty) from the output station S8 to the input station S7.
At this point the grouping unit C is in the situation illustrated in figure 12 and the cycle described above begins again.
It is important to note that each pocket 47 of the transfer conveyor 46 initially receives a first wrap 3 in the output station S8 and subsequently receives a second wrap 3 (which completes the group of two wraps 3) in the output station S9; therefore in each pocket 47 of the transfer conveyor 46 the group of two wraps 3 is formed in two moments and in two different positions: in the output station S8 a first wrap 3 is inserted and, temporally later and spatially downstream, in the output station S9 a second wrap 3 is inserted (which completes the group of two wraps 3). Obviously, the movements and spacings of the pockets 47, 48 and 49 must be configured so that in the output station S8 in each pocket 47 of the transfer conveyor 46 a first wrap 3 is inserted in a first position and subsequently in the output station S9 in each pocket 47 of the transfer conveyor 46 a second wrap 3 is inserted in a second position different from the first position and completely with the first position.
According to a possible embodiment, each pocket 47 of the transfer conveyor 46 could comprise a very thin dividing wall (for example having a thickness of 1-2 mm) which divides the two wraps 3 of the same group of wraps 3, creating two single cells each designed to house a single wrap 3. In this way, in the output station S8 the first wrap 3 which enters the corresponding pocket 47 of the transfer conveyor 46 remains "at its place" (as it is retained in the corresponding single cell) and therefore does not undesirably invade the space that will be set to accommodate the second wrap 3 which will enter the pocket 47 when the pocket 47 will be in the output station S9.
Obviously, during the movements of the pockets 48 and 49, also the transfer conveyor 46 takes its own steps forwards to move the full pockets 47 (i.e. containing groups of two wraps 3) from the output stations S8 and S9 and towards the transfer station S6 and replace the full or half-full pockets 47 (half-empty, i.e. full/empty only for a half) with the same number of empty or half-full pockets 47 (half-empty) in the output stations S8 and S9.
According to a preferred, but not binding, embodiment, the movement of the various components (wrapping wheels, feed conveyors, pushers, mobile folders...) of the packing machine 29 is carried out by means of respective electric motors that are mechanically independent from each other and are virtually synchronised (i.e. moved in phase) (i.e. not by means of a physical constraint, but by means of a control constraint). Normally an electric motor is considered as a reference ("master") and all other electric motors ("slave") follow the position of the reference electric motor ("master").
Embodiments described herein may be combined with each other.
The grouping unit C described above has several advantages.
First, the grouping unit C described above allows to operate at a high production speed (i.e. with a high number of wraps 3 produced in a time unit) without damaging the wraps 3.
In addition, the grouping unit C described above allows the format of the cigarette packets 1 to be changed relatively easily and quickly.
The grouping unit C described above allows to form, in the pockets 47 of the transfer conveyor 46, groups of two wraps 3 receiving from the wrapping conveyor 37 a succession of single wraps 3 (as the wrapping conveyor 37 operates on a single line). That is, the grouping unit C allows to transform a succession of single wraps 3 (moved forward by the wrapping conveyor 37) into a succession of pairs of two wraps 3 (moved forward by the transfer conveyor 46).
Finally, the grouping unit C described above is compact and has optimal accessibility to all its components (a feature particularly useful during the execution of a format change). The embodiment illustrated in the appended figures relates to the making of a cigarette packet, but the present invention is also applicable without substantial modifications to the making of any other kind of packets for smoking articles (e.g., a cigar packet, a packet of electronic cigarettes of liquid vaporization type, a packet of new generation cigarettes without tobacco combustion...).

Claims

A grouping unit (C) to form a group consisting of two wraps (3), each containing a group (14) of smoking articles; the grouping unit (C) comprises:
two and only two pockets (48, 49), each designed to house a respective wrap (3);

two output stations (S8, S9);

an input station (S7) arranged between the two output stations (S8, S9);

an insertion device (50), which is designed to insert one single wrap (3) into a first pocket (48) standing alone in the input station (S7) or into a second pocket (49) standing alone in the input station (S7);

an extraction device (51), which is designed to extract one single wrap (3) from the first pocket (48) standing alone in a first output station (S8) or from the second pocket (49) standing alone in a second output station (S9), which is opposite the first output station (S8) relative to the input station (S7); and

a first moving device (52), which is designed to move, along a moving direction (D1), the first pocket (48) between the input station (S7) and the first output station (S8) and, simultaneously, is designed to move the second pocket (49) between the second output station (S9) and the input station (S7) so that in the input station (S7) there always is one single pocket (48, 49), while the other pocket (49, 48) is in one of the two output stations (S8, S9).
The grouping unit (C) according to claim 1, wherein the input station (S7) and the output stations (S8, S9) are aligned with one another along the moving direction (D1).
The grouping unit (C) according to claim 1 or 2, wherein the two pockets (48, 49) are aligned with one another along the moving direction (D1).
The grouping unit (C) according to claim 1, 2 or 3, wherein the first moving device (52) comprises a first rigid support element (53), on which there are mounted the first pocket (48) and the second pocket (49), which, hence, always move in a synchronous manner.
The grouping unit (C) according to one of the claims from 1 to 4 and comprising a transfer conveyor (47), which moves along a transfer path (P3) parallel to the moving direction (D1) and is provided with a plurality of third pockets (47), each designed to house a group consisting of two wraps (3) side by side and designed to receive a first wrap (3) in the first output station (S8) and a second wrap (3) in the second output station (S9) arranged downstream of the first output station (S8) and at a given distance from the first output station (S8).
The grouping unit (C) according to claim 5, wherein each third pocket (47) comprises a dividing wall, which divides the two wraps (3) of the same group of wraps (3).
The grouping unit (C) according to claim 6, wherein, in each third pocket (47), the dividing wall creates two single cells, each designed to house one single wrap (3).
The grouping unit (C) according to one of the claims from 1 to 7, wherein:
the insertion device (50) comprises one single first pusher (54), which is arranged in the area of the input station (S7) and is movable perpendicularly to the moving direction (D1); and

the extraction device (51) comprises two sole second pushers (55), which are arranged in the area of the two output stations (S8, S9) and are movable perpendicularly to the moving direction (D1).
The grouping unit (C) according to claim 8 and comprising:
a second common rigid support element (56), which supports both the first pusher (54) and the two second pushers (55); and

a second moving device (57), which alternatively moves the second support element (56) both along a main horizontal direction (D2), which is perpendicular to the moving direction (D1), and along a secondary vertical direction (D3), which is perpendicular to the main direction (D2) and perpendicular to the moving direction (D1).
The grouping unit (C) according to claim 9, wherein the second moving device (57) causes the second support element (56) to cover a work stroke by moving the second support element (56) only along the main direction (D2) and causes the second support element (56) to cover a return stroke by moving the second support element (56) at first in the secondary direction (D3) and downwards, then in the main direction (D2) along a path that is contrary to the work stroke and, finally, in the secondary direction (D3) and upwards.
A grouping method to form a group consisting of two wraps (3), each containing a group (14) of smoking articles; the grouping method comprises the steps of:
inserting, by means of an insertion device (50), one single wrap (3) into one single first pocket (48) standing alone in the input station (S7) or into one single second pocket (49) standing alone in the input station (S7);

extracting, by means of an extraction device (51), one single wrap (3) from the first pocket (48) standing alone in a first output station (S8) or from the second pocket (49) standing alone in a second output station (S9), which is opposite the first output station (S8) relative to the input station (S7); and

moving, by means of a first moving device (52) and along a moving direction (D1), the first pocket (48) between the input station (S7) and the first output station (S8) and, simultaneously, moving the second pocket (49) between the second output station (S9) and the input station (S7) so that in the input station (S7) there always is one single pocket (48, 49), while the other pocket (49, 48) is in one of the two output stations (S8, S9).