ITBO20130255A1 - MEASUREMENT METHOD AND PACKAGING MACHINE TO MAKE A SEALED PAPER. - Google Patents

Description

DESCRIPTION

"Wrapping method and packing machine to make a sealed wrapping."

TECHNIQUE SECTOR

The present invention relates to a wrapping method and a packing machine for making a sealed wrapping.

The present invention finds advantageous application to a sealed cigarette wrapping provided with a reclosable extraction opening, to which the following description will make explicit reference without thereby losing generality.

ANTERIOR ART

Normally, a rigid packet of cigarettes with a hinged lid comprises an inner wrapper that encloses a group of cigarettes and a rigid outer wrapper that houses the inner wrapping inside it.

Recently, in order to better preserve the organoleptic characteristics of the tobacco of cigarettes, the use of a sealed internal wrapping has been proposed, which is made by folding and heat-sealing a sheet of waterproof wrapping material. To allow the extraction of the cigarettes, the sealed internal wrapping is provided with an extraction opening which is normally covered by an adhesive panel of the â € œopen and closeâ € type; in particular, the adhesive panel is provided with a repositioning adhesive which does not dry and which allows the adhesive panel to be blocked several times in a closed position of the cigarette extraction opening. Normally, the sealed internal wrapping is internally provided with a rigid reinforcement element which essentially has the function of giving greater stiffness and greater stability of shape to the sealed inner wrapping in order to prevent the sealed inner wrapping itself it collapses on itself after having extracted a part of the cigarettes contained inside, making it difficult to extract the remaining cigarettes and in particular making the opening and subsequent closing of the adhesive panel extremely complicated. A further function of the reinforcing element is to keep the group of cigarettes in the correct conformation, as well as to provide adequate mechanical protection to the group of cigarettes, during the formation of the sealed internal wrapping (i.e. during the folding / sealing of the sheet of wrapping).

Patent application WO2013053408A1 describes a sealed internal wrapping in which the wrapping sheet has through vent openings which are used to better evacuate (completely or partially) the air contained inside the sealed wrapping 3 before watertight closure of the sealed package 3 itself. During the execution of the transversal welds of the sealed wrapping, the vents are closed making the sealed wrapping watertight. However, it has been observed that the through vent openings described in patent application WO2013053408A1 do not always allow correct evacuation of the air contained inside the sealed wrapping before the watertight closure of the sealed wrapping itself.

DESCRIPTION OF THE INVENTION

The object of the present invention is to provide a wrapping method and a packing machine for making a sealed wrapping, which wrapping method and packing machine are free from the drawbacks described above and are, at the same time, easy and economical to produce.

In accordance with the present invention, a wrapping method and a packing machine are provided for making a sealed wrapping, 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 a non-limiting example of embodiment, in which:

Figure 1 is a front perspective view and in a closed configuration of a packet of cigarettes provided with a sealed wrapping made in accordance with the present invention; Figure 2 is a front perspective view of the packet of cigarettes of Figure 1 in a partially open configuration; Figure 3 is a front perspective view of the cigarette packet of Figure 1 in a completely open configuration;

Figure 4 is a front perspective view of a sealed wrapping of the package of Figure 1;

- figure 5 is a rear perspective view of the sealed wrapping of figure 4;

- figure 6 is a front perspective view of a group of cigarettes contained in the internal package of figure 4;

- figure 7 is a front perspective view of the sealed wrapping of figure 4 before a final folding of the two lateral fin seams;

- figure 8 is a plan view of a sheet of heat-sealable wrapping used to make the sealed wrapping of figure 4;

- figure 9 is a front perspective view of a reinforcement element contained in the internal wrapping of figure 4;

- figure 10 is a rear perspective view of the reinforcement element of figure 8;

- figure 11 is a front perspective view of the reinforcing element of figure 8 before a final folding of a central stabilization tab;

- figure 12 is a view of a blank used to make the reinforcement element of figure 8;

Figure 13 is a schematic plan view of an initial wrapping unit of a packing machine which produces the packet of cigarettes of Figure 1;

- figure 14 is a schematic side view of the initial wrapping unit of figure 13;

- figure 15 is a perspective and schematic view of part of the initial wrapping unit of figure 13;

- figure 16 is a perspective and schematic view of a coupling station of the initial wrapping unit of figure 13;

- figure 17 is a schematic view of a feeding device of the coupling station of figure 16; - figures 18 and 19 are two schematic and side section views of part of the coupling station of figure 16 in two different operating configurations;

- figures 20 and 21 are two schematic and front views of part of the coupling station of figure 16 in two different operating configurations;

Figure 22 is a schematic and plan view of a transfer device of the initial wrapping unit of Figure 13; Figure 23 is a schematic and front view of a transverse sealing device and of a folding wheel of the initial wrapping unit of Figure 13;

- figures 24 and 25 are two schematic views, frontal and on an enlarged scale, of the transversal welding device of figure 13; - figure 26 is a front perspective view of the sealed wrapping of figure 4 before a final folding of the two lateral fin seams and in the presence of an air vent channel; and - figure 27 is a schematic view of a heated surface of a welding head which performs a transversal sealing of the sealed wrapping of figure 26.

PREFERRED EMBODIMENTS OF THE INVENTION In Figures 1, 2 and 3, the number 1 indicates as a whole a rigid packet of cigarettes. The pack 1 of cigarettes comprises an external container 2 made of cardboard or rigid cardboard and shaped like a cup and a sealed wrapping 3 (better illustrated in figures 4 and 5) housed inside the container 2.

The external container 2 has an open upper end and is provided with a lid, which is cup-shaped and is hinged to the external container 2 along a hinge (illustrated in figure 3) to rotate, with respect to the external container 2 itself. , between an open position (illustrated in Figure 2) and a closed position (illustrated in Figures 1 and 3) of the open upper end. The lid, when in its closed position, gives the outer container 2 a rectangular parallelepiped shape having an upper wall and a lower wall parallel and opposite to each other, a front wall and a rear wall (in which the hinge is obtained) between them parallel and opposite, and two side walls parallel and opposite to each other. Four longitudinal edges are defined between the side walls and the front and rear walls, while eight transverse edges are defined between the upper and lower walls and the front, rear and side walls. According to what is illustrated in figures 4 and 5, the sealed package 3 encloses a group 4 of cigarettes (shown in figure 6) of parallelepiped shape and has a cigarette extraction opening 5 at the top and front (shown in broken lines in figure 4) ; the cigarette extraction opening 5 is placed centrally, it is closed by an adhesive panel 6 of the â € œopen & closeâ € type and affects a portion of a front wall of the sealed packet 3 and a portion of a wall top of the sealed wrapper 3. The adhesive panel 6 normally adheres to the part of the sealed wrapping 3 arranged around the extraction opening 5 to close (seal) the extraction opening 5 itself and can be temporarily raised to free the extraction opening 5 and therefore it allows the extraction of a cigarette through the extraction opening 5 itself.

The sealed wrapping 3 is made by folding a sheet 7 of waterproof and heat-sealable wrapping material (illustrated in figure 8), which has a rectangular shape and has an incision that is shaped like a â € œUâ € and defines the ™ extraction opening 5. The adhesive panel 6 is glued to the wrapping sheet 7, which has a rectangular shape and completely covers the incision (ie the extraction opening 5); between the adhesive panel 6 and the wrapping sheet 7 there is a repositionable adhesive which does not dry (that is, which always remains sticky), i.e. the adhesive which allows even after a long time to separate the adhesive panel 6 from the wrapping sheet 7 and then to reunite the adhesive panel 6 to the wrapping sheet 7 for a high number of times. According to a preferred embodiment, the repositionable adhesive which does not dry is previously applied to an internal face of the adhesive panel 6 before coupling the adhesive panel 6 to the wrapping sheet 7.

The presence of the repositionable adhesive between the adhesive panel 6 and the wrapping sheet 7 determines the permanent gluing (which is never separated even in use) of the portion of the wrapping sheet 7 enclosed inside the incision (ie in correspondence with the extraction opening 5) to the adhesive panel 6; therefore, when the adhesive panel 6 is lifted from the wrapping sheet 7, the portion of the adhesive panel 6 enclosed inside the incision (i.e. in correspondence with the extraction opening 5) is raised together with the adhesive panel 6, freeing the opening 5 extraction. Furthermore, the presence of the repositionable adhesive 16 between the adhesive panel 6 and the wrapping sheet 7 determines a temporary gluing (that is, which in use is separated) between the portion of the wrapping sheet 7 that surrounds the incision (i.e. ̈ which surrounds the extraction opening 5) and the adhesive panel 6 so as to normally keep the adhesive panel 6 in contact with the wrapping sheet 7 to close (seal) the extraction opening 5.

The adhesive panel 6 is provided with a gripping tab 8, which is free of adhesive that can be repositioned on the side facing the wrapping sheet 7 (i.e. on the surface facing the wrapping sheet 7) and is arranged near the opening 5 and below the extraction opening 5 itself. The catchable tab 8 is designed to facilitate gripping of the adhesive panel 6 when lifting the adhesive panel 6 itself; in other words, to lift the adhesive panel 6 a user can easily grasp a gripping tab 8, which is in no way fixed to the wrapping sheet 7 unlike the rest of the adhesive panel 6.

As illustrated in figures 4 and 5, the sealed wrapping 3 is stabilized, that is, it is kept in the folded configuration, by means of a central 9 (or 9 longitudinal) fin welding which is arranged in correspondence with a front wall and of lateral walls of the sealed package 3 and by means of two lateral fin welds 10 (or transverse welds 10) which are arranged in correspondence with the side walls of the sealed package 3. The central fin welding 9 determines the formation of a tubular wrapping having two open ends in correspondence with the side walls of the sealed wrapping 3 and is initially perpendicular to the front wall of the sealed wrapping 3; after its formation, the central fin seal 9 is bent 90 ° against the front wall of the sealed package 3 (as illustrated in Figures 4 and 7). The two lateral fin welds 10 determine the lateral closure of the tubular wrapping and are initially perpendicular to the corresponding lateral walls of the sealed wrapping 3 (as illustrated in figure 7); after their formation, the two lateral fin seals 10 are bent by 90 ° against the corresponding lateral walls of the sealed wrapping 3 (as illustrated in Figures 4 and 5).

According to what is illustrated in Figure 7, each lateral fin-type welding 10 is carried out by determining the formation of two fins 11 with triangular ends which protrude from opposite sides from the corresponding lateral wall of the sealed package 3; after having bent each lateral fin seal 10 by 90 ° against the corresponding side wall of the sealed wrapping 3, the two triangular end flaps 11 are bent by 180 ° against the corresponding side wall of the sealed wrapping 3 and above the side welding 10 with fin previously folded. According to a possible embodiment, each fin 11 having a triangular end is heat-sealed to the corresponding side wall of the sealed package 3 to remain in the desired position illustrated in Figures 4 and 5; alternatively, each fin 11 having a triangular end could be maintained in the desired position illustrated in Figures 4 and 5 solely by the presence of the external container 2 which surrounds the sealed package 3.

According to what is illustrated in figures 9 and 10, the sealed package 3 comprises a reinforcing element 12, which is made of cardboard or rigid cardboard (completely similar to the cardboard or rigid cardboard making up the external container 2). conformed to â € œUâ € and is placed inside the sealed package 3 in contact with the group 4 of cigarettes.

The reinforcing element 12 comprises a front wall 13 of rectangular shape arranged in contact with a front wall of the group 4 of cigarettes, a pair of side walls 14, which are connected to opposite sides of the front wall 13 and are arranged at contact with the side walls of the group 4 of cigarettes, and a lower wall 15 arranged in contact with the lower wall of the group 4 of cigarettes. The front wall 13 has a window that is arranged above, is shaped like a â € œUâ €, and facilitates the extraction of cigarettes from group 4 of cigarettes as it leaves an upper area of the front wall of group 4 of cigarettes exposed at the extraction opening 5. Furthermore, the reinforcing element 12 comprises two lateral stabilizing tabs 16 which are connected to the lateral walls 14 and are bent 90 ° against an external surface of the lower wall 15 (i.e. on the opposite side with respect to the group 4 of cigarettes), and of a central stabilization tab 17 which is connected to the lower wall 15 and is bent 180 ° against the outer surface of the lower wall 15 (i.e. on the opposite side with respect to the group 4 of cigarettes) and above the two stabilization tabs 16 side folded previously. To better highlight the bending of the stabilization tabs 16 and 17, figure 11 illustrates the reinforcement element 12 before the final bending of the central stabilization tab 17, i.e. before resting the central stabilization tab 17 against the surface of the lower wall 15 (ie on the opposite side with respect to the group 4 of cigarettes) and above the two lateral stabilizing tabs 16 folded previously.

As better illustrated in Figure 12, the two lateral stabilization tabs 16 are connected to the corresponding lateral walls 14 of the reinforcement element 12 along two transverse fold lines and the central stabilization tab 17 is connected to the lower wall 15 of the Reinforcement element 12 along a further transverse fold line which is initially parallel to the other two transverse fold lines.

During the manipulation of the assembly consisting of the group 4 of cigarettes and the reinforcement element 12, it is possible to stabilize the reinforcement element 12 (i.e. prevent the reinforcement element 12 from abandoning the desired folded configuration) simply pushing from the outside (ie from the opposite side with respect to the group 4 of cigarettes) on the lower wall 15 (or better on the stabilization tabs 16 and 17 that cover the lower wall 15 externally) by means of a pad (better described below); in fact, by pushing from the outside (ie from the opposite side with respect to the group 4 of cigarettes) on the lower wall 15 by means of a pad, the stabilization tabs 16 and 17 are kept in the correct position against the lower wall 15. In other words, by pushing from the outside (i.e. from the opposite side with respect to the group 4 of cigarettes) on the lower wall 15, the stabilization tabs 16 and 17 are kept clamped between the pad and the lower wall 15 â € œfreezingâ € the desired configuration folded back of the reinforcement element 12.

When the sealed package 3 is complete, that is the end of the formation of the sealed package 3, the function of the reinforcing element 12 is to give greater rigidity and greater stability of shape to the sealed package 3. in order to avoid that the sealed package 3 itself collapses on itself after having extracted a part of the cigarettes contained in the sealed package 3, making the extraction of the remaining cigarettes complicated and in particular making the extraction extremely complicated opening and subsequent reclosing of the adhesive panel 6. During the formation of the sealed package 3, the functions of the reinforcing element 12 are to provide adequate mechanical protection to the cigarettes and to simplify / improve the handling of the group 4 of cigarettes (i.e. to prevent the group 4 of cigarettes from flakes).

In figure 13, the number 18 indicates as a whole a packing machine which produces the packet 1 of cigarettes described above.

The packing machine 18 comprises an initial wrapping unit 19 which creates the sealed wrapping 3 by forming the cigarette group 4 and folding and sealing the wrapping sheet 7 around the cigarette group 4 and a final wrapping unit 20 (note and illustrated in a very schematic way) which realizes the external container 2 by folding in succession a collar and a blank around the sealed package 3.

The initial wrapping unit 19 comprises a forming station 21 in which the group 4 of cigarettes is formed, a coupling station 22 in which the group 4 of cigarettes is coupled to the reinforcing element 12, and a station 23 of wrapping in which the wrapping sheet 7 is wrapped around the group 4 of cigarettes to form the sealed wrapping 3.

As illustrated in Figure 15, the forming station 21 comprises a vertical hopper 24 provided with a plurality of lower outlets, and a belt forming conveyor 25 which supports a plurality of forming pockets 26 and advances with continuous motion for move the forming pockets 26 themselves along a forming path P1 (illustrated in Figure 16) which extends in front of the outlets of the hopper 24. As illustrated in Figure 16, the forming conveyor 25 comprises a belt which is closed in a ring and wraps around two motorized end pulleys; consequently, the formation path P1 is shaped like a â € œUâ € and has a lower straight branch that develops horizontally and is arranged in front of the outlets of the hopper 24, and an upper straight branch that crosses station 22 and ends at a transfer device 36 which transfers each group 4 of cigarettes contained in a formation pocket 26 into a wrapping seat 27 of a wrapping conveyor 28 which advances with continuous motion parallel and in synchronism with the conveyor 25 to move the wrapping seats 27 along a straight and horizontal wrapping path P2.

According to a preferred embodiment, the two motorized end pulleys around which the belt of the forming conveyor 25 is wound are movable with an alternating linear movement parallel to the rectilinear portions of the forming path P1; at the same time, the rotation speed of the two motorized end pulleys varies over time in synchronism with their alternating linear movement. The combination of the alternating linear movement of the pulleys with the variation of the rotation speed of the pulleys themselves allows to temporarily stop the formation pockets 26 which are located in front of the outlet openings of the hopper 24 (i.e. the formation pockets 26 which are located in the straight lower branch of the formation path P1) to allow the transfer of the groups 4 of cigarettes from the outlets of the hopper 24 to the formation pockets 26; at the same time, the combination of the alternating linear movement of the pulleys with the variation of the rotation speed of the pulleys themselves allows to keep the advancement speed of the formation pockets 26 constant in the upper straight branch of the formation path P1, so that the forming pockets 26 which are located in the upper rectilinear branch of the forming path P1 are always in phase and synchronized with the wrapping seats 27 of the wrapping conveyor 28 (which advance with continuous motion along the wrapping path P2).

The coupling station 22 comprises a belt coupling conveyor 29 which is arranged alongside the forming conveyor 25 so as to advance the reinforcing element 12 parallel to the upper rectilinear branch of the forming path P1. According to a preferred embodiment, the coupling conveyor 29 is provided with suction and holds the reinforcing element 12 by suction in contact with a lower surface of the conveyor belt; in other words and as well illustrated in Figures 18 and 19, the coupling conveyor 29 is arranged higher than the formation conveyor 25 and the reinforcing element 12 is suspended by suction below the coupling conveyor 29 .

As illustrated in Figure 17, a feeding device 30 is provided which unwinds from a reel 31 a continuous ribbon of wrapping material which is made to advance along a straight and horizontal feed path P3 which extends perpendicularly to the coupling conveyor 29. . In particular, the continuous web of wrapping material is passed through an embossing and cutting device 32 to form the pre-weakened fold lines in each reinforcing element 12 and then to separate the individual reinforcing elements 12 from the continuous web itself. . At the end of the feed path P3, a lifter 33 is arranged which is movable vertically (ie perpendicularly to the feed path P3 and to the coupling conveyor 29) with alternating movement; the lifter 33 pushes the reinforcement element 12 from the final portion of the feed path P3 to the coupling conveyor 29 to which the reinforcement element 12 adheres by suction.

As illustrated in Figures 18 and 19, the coupling conveyor 29 of the coupling station 22 cooperates with the forming conveyor 25 to rest the reinforcing element 12 on the forming pocket 26 along the upper rectilinear branch of the forming path P1 . While the reinforcement element 12 rests on the formation pocket 26 (i.e. along the upper straight branch of the formation path P1) a pair of folding devices 34 and 35 (schematically illustrated in figure 16) arranged in succession fold (as previously described and as illustrated in Figures 9 and 10) the reinforcing element 12 partially around the forming pocket 26 and therefore partially around the group 4 of cigarettes contained in the forming pocket 26. Finally, at the end of the formation path P1, a transfer device 36 (schematically illustrated in figure 16) extracts together and simultaneously the reinforcing element 12 and the group 4 of cigarettes from the formation pocket 26 to insert the element 12 and the group 4 of cigarettes in the corresponding wrapping pocket 27 of the wrapping conveyor 28. As illustrated in Figures 18 and 19, the formation pocket 26 comprises an initial part 37 arranged in correspondence with an inlet opening of the group 4 of cigarettes (i.e. in correspondence with the opening through which the group 4 of cigarettes enters the pocket 26 formation), and a final part 38 arranged in correspondence with an outlet opening of the group 4 of cigarettes (ie in correspondence with the opening through which the group 4 of cigarettes exits from the formation pocket 26). The reinforcement element 12 is placed only on the final part 38 of the formation pocket 26 so that initially the reinforcement element 12 is longitudinally misaligned with respect to the group 4 of cigarettes and is longitudinally aligned with the group 4 of cigarettes only when it is extracted from the formation pocket 26 together with the group 4 of cigarettes. According to a preferred embodiment, the formation pocket 26 has a tubular shape with a rectangular section and has a lower wall and an upper wall parallel and opposite to each other (visible in figures 18 and 19) and two side walls parallel and opposite to each other. (not visible in figures 18 and 19); the thickness of the upper and lateral walls of the final part 38 is less than the thickness of the upper and lateral walls of the initial part 37 so that the reinforcement element 12 which rests on the final part 38 of the formation pocket 26 is arranged in close proximity to group 4 of cigarettes.

As illustrated in figures 18 and 19, a first end of the front wall 13 of the reinforcement element 12 is placed on the formation pocket 26 and a second end of the front wall 13 of the reinforcement element 12 opposite the first end is retained by suction by the coupling conveyor 29 which advances parallel to the forming conveyor 25. A lower surface of the front wall 13 of the reinforcing element 12 rests on the formation pocket 26 (in particular on the upper wall of the formation pocket 26), while an upper surface opposite the lower surface of the front wall 13 of the element 12 of reinforcement is in contact with the coupling conveyor 29 which holds it by suction.

Once the reinforcement element 12 has been placed on the formation pocket 26, the folding device 34 folds the reinforcement element 12 around the formation pocket 26 while the front wall 13 of the reinforcement element 12 It is held by the coupling conveyor 29. The folder device 34 comprises a folder 39 which moves vertically (i.e. transversely to the formation path P1) between a rest position (illustrated in Figures 18 and 20) in which the folder 39 is away from the reinforcing element 12 and a working position (illustrated in Figures 19 and 21) in which the bender 39 embraces the reinforcement element 12 itself. As previously said, the formation pocket 26 is advanced with continuous motion along the upper branch of the formation path P1; consequently, the folder 39 is also movable parallel to the forming path P1 to follow the forming pocket 26 along a portion of the forming path P1 itself. According to a preferred embodiment illustrated in Figures 18-21, the bender 39 comprises four vertically oriented `` legs '' 40 (i.e. four folding elements 40) which embrace the coupling conveyor 29 at the front and rear and laterally embrace the element 12 reinforcement; when the folder 39 moves from the rest position (illustrated in figures 18 and 20) to the working position (illustrated in figures 19 and 21), the four folding elements 40 bend the side walls 14 of the element 12 by 90 ° reinforcement with respect to the front wall 12 of the reinforcement element 12. Furthermore, the folder 39 comprises a further folding element 41 (illustrated in Figures 20 and 21) which is arranged transversely to two rear folding elements 40; when the folder 39 moves from the rest position (illustrated in figures 18 and 20) to the working position (illustrated in figures 19 and 21), the further folding element 41 bends the rear wall 15 of the element by 90 ° 12 of reinforcement with respect to the front wall 12 of the reinforcement element 12.

According to a preferred embodiment illustrated in Figures 18-21, the folder 39 cooperates with a counter-folder 42 which is U-shaped and, when the folder 39 moves towards the working position (illustrated in Figures 19 and 21), rests against an internal surface of the front wall 13 of the reinforcing element 12 on the opposite side with respect to the bender 39 itself. In this way, the reinforcing element 12 is bent between the bender 39 and the counter bender 42 to improve the quality of the bending. Obviously, the counter-folder 42 is also movable parallel to the forming path P1 to follow, together and in a synchronized way with the folder 39, the forming pocket 26 along a section of the forming path P1 itself.

Summarizing what has been described above, the lower wall 15 of the reinforcement element 12 is bent simultaneously with the two side walls 14 of the reinforcement element 12 by means of the single bender 39 which is movable both transversely to the formation path P1 (to carry out the bending), and parallel to the forming path P1 (to follow the forming pocket 26 during bending).

As shown in Figure 16, the folding device 35 is arranged along the upper branch of the formation path P1 downstream of the folding device 34 and bends the two lateral stabilizing tabs 16 of the reinforcing element 12 against a surface external of the lower wall 15 of the reinforcing element 12 to be arranged on the opposite side with respect to the group 4 of cigarettes; subsequently, the folding device 35 bends the central stabilization tab 17 of the reinforcement element 12 against the outer surface of the lower wall 15 to be arranged on the opposite side with respect to the group 4 of cigarettes and above the two stabilization tabs 16 side folded previously. Preferably, the folding device 35 comprises a movable finger (of a known type and not shown in detail) which bends a tab 16 for lateral stabilization of the reinforcing element 12 against the direction of advancement of the formation pocket 26, and comprises helices bending (ie fixed folders of a known type and not illustrated in detail) which bend the other lateral stabilization tab 16 of the reinforcing element 12 and the central stabilization tab 17 of the reinforcing element 12.

After finishing the bending of the central stabilization tab 17 of the reinforcement element 12 (i.e. after having finished bending the reinforcement member 12), continuous pressure is applied to the central stabilization tab 17 in order to maintain the central stabilization tab 17 pressed against the lower wall 15 of the sealed package 3 with the interposition of lateral stabilization tabs 16. In particular, the pressure on the central stabilization tab 17 of the reinforcing element 12 is maintained from the end of the folding of the central stabilization tab 17 until the wrapping sheet 7 is wrapped around the group 4 of cigarettes enclosed in the element 12 reinforcement. According to a preferred embodiment, the pressure on the central stabilization tab 17 is generated by bringing pads 43 and 44 (illustrated in Figures 16 and 22) into contact with the central stabilization tab 17 of the reinforcing element 12; in particular, an initial pad 43 is provided which is arranged along the upper branch of the formation path P1 immediately downstream (without solution of continuity) of the folding device 35, and a subsequent final pad 44 which is arranged along the path P2 of wrapping. In other words, the pads 43 and 44 constitute a pressure device which is arranged downstream of the folding device 35 and applies a pressure on the central stabilization tab 17 of the reinforcing element 12 so as to maintain the central stabilization tab 17 pressed against the lower wall 15 of the reinforcement element 12 with the interposition of the lateral stabilization tabs 16.

As previously said, between the formation path P1 and the wrapping path P2 there is the transfer device 36 (shown schematically in Figure 16) which simultaneously extracts the reinforcing element 12 and the group 4 of cigarettes from the formation pocket 26 of the formation conveyor 25 for inserting the reinforcing element 12 and the group 4 of cigarettes into the corresponding wrapping pocket 27 of the wrapping conveyor 28 which advances parallel and in synchronism with the forming conveyor 25. As previously said, the reinforcement element 12 is placed only on the final part 38 of the formation pocket 26 in such a way that initially the reinforcement element 12 is longitudinally misaligned with respect to the group 4 of cigarettes and is longitudinally aligned with the group 4 of cigarettes when extracted from the formation pocket 26 together with the group 4 of cigarettes; in other words, when the transfer device 36 extracts together the reinforcing element 12 and the group 4 of cigarettes from the forming pocket 26 of the forming conveyor 25, it also gives a relative movement between the reinforcing element 12 and the group 4 of cigarettes to arrive at a longitudinal alignment between the two.

It is important to note that thanks to the fact that the group 4 of cigarettes is already partially inserted inside the reinforcement element 12, when the group 4 of cigarettes is completely inserted into the reinforcement element 12 by the transfer device 36 no type of jamming occurs between the tips of the cigarettes of the group 4 of cigarettes and the edge of the reinforcing element 12; consequently, the transfer performed by the transfer device 36 can be carried out in speed without any risk of jamming which would entail the destruction of the group 4 of cigarettes and the consequent stop of the packing machine 18. In other words, folding the group 4 of cigarettes around the formation pocket 26 allows to avoid jamming between the tips of the cigarettes of the group 4 of cigarettes and the edge of the reinforcing element 12 at the moment of the entry of the group 4 of cigarettes. cigarettes in the reinforcement element 12.

The transfer device 36 is arranged at the end of the formation path P1 and transfers the reinforcing element 12 and the group 4 of cigarettes from the formation pocket 26 of the formation conveyor 25 to the wrapping seat 27 of the wrapping conveyor 28. As illustrated in Figure 22, the transfer device 36 comprises a pusher 45 which rests on one end of the group 4 of cigarettes and pushes the group 4 of cigarettes out of the formation pocket 26 and a counter-pusher 46 which rests on the Opposite end of the group 4 of cigarettes with the interposition of the lower wall 15 (and of the tabs 16 and 17) of the reinforcement element 12.

As shown in Figure 15, along the wrapping path P2 there is a winding station 47 of the flow-pack type (schematically illustrated in Figure 15) in which the wrapping sheet 7 is wound longitudinally in a tube around the assembly 4 of cigarettes to form a tubular wrapper. In the wrapping station 47 there is a longitudinal sealing device 48 (of known type) which performs the longitudinal sealing 9 on the tubular wrapping to stabilize the shape of the tubular wrapping itself; coupled to the longitudinal welder device 48 is a known bender (not shown) which, immediately after its formation, bends the longitudinal weld 9 shaped like a fin by 90 ° against a corresponding wall of the group 4 of cigarettes (with the interposition of the front wall 13 of the reinforcement element 12). In the wrapping station 47 the wrapping sheet 7 is fed from below to arrange the longitudinal fin-shaped seal 9 at the front wall of the group 4 of cigarettes (as illustrated in Figures 4 and 5).

Downstream of the longitudinal sealing device 48 there is a transversal sealing device 49 which cyclically creates a succession of transverse welds 10 on the tubular wrapping, each of which is arranged between two groups 4 of successive cigarettes; moreover, the transverse sealing device 49 makes a transversal cut in the center of each transverse seal 10 to separate the two consecutive sealed wrappers 3 which share the same transverse seal 10.

As illustrated in Figure 23, downstream of the transverse sealing device 49 there is a bending wheel 50 which is mounted to rotate around an axis 51 of horizontal rotation and is provided with a series of bending pockets 52, each of the which is suitable for receiving a corresponding sealed package 3. The bending wheel 50 is provided with a bending device 53 which is preferably provided with fixed bending helices (i.e. with fixed benders) and initially bends each fin-shaped transverse weld 10 by 90 ° against a corresponding side wall of group 4 of cigarettes (with the interposition of a side wall 14 of the reinforcement element 12); subsequently, or after having bent each lateral fin seal 10 by 90 ° against the corresponding side wall of the sealed wrapping 3, the folding device 53 folds the triangular end flaps 11 by 180 ° against the corresponding lateral wall of the wrapping 3 sealed and above the side weld 10 with the fin folded previously (as illustrated in Figures 4 and 5). Furthermore, the folding wheel 50 is provided with a sealing device 54 which heat-welds each fin 11 of triangular end to the corresponding side wall of the sealed package 3 in order to remain in the desired position illustrated in Figures 4 and 5; according to a different embodiment, each fin 11 with triangular end could be kept in the desired position illustrated in Figures 4 and 5 solely by the presence of the external container 2 surrounding the sealed wrapping 3 and in this case the sealing device 54 would be absent . It is important to note that the welds performed by the welder device 54 fix both each fin 11 with triangular ends and each lateral fin weld 10 to the corresponding side wall of the sealed wrapping 3 so as to block a folded configuration of the fins 11 of ends and to lock a folded configuration of the transverse fin welds 10.

As shown in Figure 23, a belt conveyor 55 is interposed between the transverse sealing device 49 and the folding wheel 50 which advances with continuous motion to transfer the sealed wrappers 3 in succession by the transverse sealing device 49 to the folding wheel 50. . The bending wheel 50 is rotatably mounted with an intermittent motion, or stepwise, around the rotation axis 51; consequently, the folding wheel 50 is provided with an inlet pusher 56 which inserts the sealed wrapping 3 inside a corresponding folding pocket 52 and with an outlet pusher 56 which extracts the wrapping 3 sealed from the inside of a corresponding folding pocket 52. According to what is illustrated in Figures 24 and 25, the transverse sealing device 49 comprises two welding drums 58 which are rotatably mounted around respective central rotation axes 59 parallel to each other, arranged on opposite sides of the wrapping path P2 along which it is advanced the tubular wrapping, and carry respective welding heads 60 cooperating with each other to clamp the tubular wrapping together during the execution of the transverse welding 10. The welding heads 60 are internally provided with cutting members 61 to make, during the execution of the transverse welding 10, a transversal cut of the tubular wrapping so as to separate a sealed wrapping 3 from the tubular wrapping itself. The lateral surface of each sealing drum 58 is covered by a compression element 62 which deforms elastically to impart a compression on the tubular wrapping in order to stretch the tubular wrapping and thus eliminate the air trapped in the tubular wrapping. inside of the tubular wrapping during the execution of the transversal welds 10; normally, the compression element 62 is made up of brushes.

Each welding head 60 of a welder drum 58 is coupled to a corresponding support element 63 which is carried by a corresponding welder drum 58, is arranged downstream of the corresponding welding head 60 with respect to the direction of advancement of the tubular wrapping along the wrapping path P2, and is placed in contact with a lower or upper wall of the tubular wrapping itself. In the embodiment illustrated in the attached figures, both welding drums 58 are provided with support elements 63 and therefore, during the execution of a transversal welding 10, two cooperating support elements 63 are arranged in contact with opposite walls of the Tubular wrapping to clamp the tubular wrapping together downstream of the welding heads 60. According to a different embodiment not shown, only the lower welding drum 60 is provided with the support elements 63 (ie the upper welding drum 60 has no support elements 63).

At the moment of carrying out the transversal seal 10, each support element 63 advances for a certain distance with a linear movement parallel to the wrapping path P2 to accompany the sealed wrapping 3 which has just been separated from the tubular wrapping continuous. For this purpose, each support element 63 is mounted movable with respect to the corresponding welding drum 58 to perform a relative movement with respect to the welding drum 58 itself; in particular, each support element 63 is rotatably mounted with respect to the corresponding sealing drum 58 to rotate around a peripheral rotation axis 64 parallel to the central rotation axis 59. According to a preferred embodiment, each welding drum 58 comprises a cam actuation system 65 for controlling the relative movement (ie relative rotation) between each support element 63 and the welding drum 58 itself. In particular, each support element 63 is connected to the corresponding welding drum 58 by means of a connection arm 66 which is hinged to the welding drum 58 itself at the peripheral rotation axis 64; one end of each connecting arm 66 opposite, with respect to the peripheral rotation axis 64, to the support element 63 is connected to a follower roller which engages a fixed cam arranged inside the corresponding welding drum 58.

Immediately downstream of the transverse sealing device 49 begins the belt conveyor 55 towards which the sealed wrappers 3 coming from the transverse sealing device 49 itself are pushed; the support elements 63 guide each sealed package 3 towards the belt conveyor 55 to ensure correct entry of the sealed package 3 into the belt conveyor 55 itself, or to prevent the sealed package 3 from getting stuck against the conveyor 55 to the belt due to undesired movements which may take place after the execution of the transverse welding 10. As better illustrated in Figure 24, in correspondence with an inlet of the belt conveyor 55 there is a pressure drum which is covered by an element which deforms elastically (typically brushes) and which pushes the sealed package 3 against the belt conveyor 55.

According to the embodiment illustrated in Figure 26, during the execution of each transversal seal 10, the transverse seal 10 itself is interrupted in a limited portion of the tubular wrapping in such a way as to leave, astride the transverse seal 10, at least one outlet channel 67 which connects the inside of the sealed package 3 with the foreign environment. The vent channel 67 is closed after the execution of the transverse welds 10 to make the sealed package 3 watertight. According to a preferred embodiment, the vent channel 67 is closed by means of a sealing weld which is carried out after the execution of the transverse welds 10 and which coincides with the weld carried out by the welder device 54 to weld the transverse fin welds 10. and / or the triangular end flaps 11 to the underlying part of the wrapping sheet 7. In other words, the same welding performed by the welder device 54 has both the function of closing the vent channel 67, and the function of fixing the transversal fin welds 10 and / or the triangular end fins 11 to the underlying part of the sheet 7 of wrapping.

As illustrated in Figure 27, each welding head 60 has a heated surface 68, which is centrally interrupted by the presence of the cutting member 61 and is pressed against the superimposed portions of the wrapping sheet 7 to achieve a corresponding sealing 10 traversal. In each welding head 60, the heated surface 68 has at least one recess 69 at which the transverse welding 10 is interrupted to leave the vent channel 67.

The vent channel 67 allows to evacuate (completely or partially) the air contained inside the sealed package 3 before the watertight closure of the sealed package 3 itself. In other words, during the execution of the transverse welds 10, the sealed wrapping 3 remains open to the external environment due to the presence of the vent channel 67 (or of the vent channels, as there could also be more channels vent); in this way, the air present inside the sealed wrapping 3 can be evacuated (completely or partially) after the execution of the transversal sealings 10. Immediately after the (complete or partial) evacuation of the air present inside the sealed wrapping 3 through the vent channel 67, the vent channel 67 itself is closed to make the sealed wrapping 3 watertight exploiting the same welding with which the transversal fin welds 10 and / or the triangular end fins 11 are fixed to the underlying part of the wrapping sheet 7.

According to a different embodiment not shown, the vent channel 67 itself is closed to make the sealed package 3 watertight by means of a further welding which is different (i.e. it is performed at different times and by different organs) from the welding performed by the soldering device 54.

As illustrated in figure 13, the initial wrapping unit 19 of the packing machine 18 is shaped like an `` L '' and has a front side (illustrated in figure 15) in which the organs that carry out the various operations of wrapping and a lateral side (illustrated in Figure 14) in which all the feeding materials of the wrapping material (ie the wrapping sheets 7 and the reinforcing elements 12) are arranged. In particular, in figure 14 it is possible to recognize the two reels 31 (one in reserve to the other) from which the continuous strip of wrapping material is unwound for the formation of the reinforcing elements 12 and the two reels 70 (one in reserve on the other) from which the continuous ribbon of wrapping material is unwound for the formation of the wrapping sheets 7.

The packing machine 18 described above has numerous advantages.

In the first place, in the packaging machine 18 described above, a correct and optimal evacuation (complete or partial) of the air contained inside the sealed package 3 is always guaranteed before the sealed package 3 is watertight; this result is obtained thanks to the presence of the vent channels 67 which are created during the execution of the transverse welds 10 and are subsequently closed by means of a further sealing weld.

Furthermore, the packing machine 18 described above is easy and inexpensive to manufacture, since the creation of the vent channels 67 is obtained very simply by means of a trivial mechanical processing of the heated surfaces 68 of the welding heads 60 to create the recesses 69; furthermore, the further sealing welding with which the vent channels 67 are closed does not involve any burden as the same welding is used with which the transverse fin welds 10 and / or the triangular end fins 11 are fixed to the underlying part of sheet 7 of wrapping.

In the non-limiting embodiment illustrated in the attached figures, the sealed package 3 of the present invention contains a group 4 of cigarettes; owing to the numerous advantages of the sealed wrapping 3 of the present invention, this sealed wrapping 3 can also be used to contain items other than cigarettes, for example foods (sweets, chocolates or other sweets).

Claims (11)

R I V E N D I C A Z I O N I 1) Wrapping method to make a sealed wrapping (3); the wrapping method includes the steps of: longitudinally wrapping a sheet (7) of wrapping around a product to form a tubular wrapping; longitudinally weld, by means of a longitudinal sealing device (48), the tubular wrapping to stabilize the shape of the tubular wrapping itself; transversely weld, by means of a transversal welder device (49), the tubular wrapping to make a pair of transversal welds (10) which close opposite ends of the tubular wrapping at the side walls of the product; the wrapping method is characterized by the fact of understanding the further phases of: interrupt, during the execution of at least one transversal weld (10), the transverse weld (10) itself in a limited portion of the tubular wrapping in such a way as to leave, astride the transverse weld (10), a channel ( 67) vent that connects the inside of the sealed package (3) with the foreign environment; And close, after making the transverse welds (10), the vent channel (67). 2) Wrapping method according to claim 1, wherein the vent channel (67) is closed by means of a sealing weld which is performed after the execution of the transverse welds (10). 3) Wrapping method according to claim 2, in which each transverse seal (10) is shaped like a fin and, after its formation, is bent 90 ° against a corresponding side wall of the product. 4) Wrapping method according to claim 3 and comprising the further step of welding the transverse fin seal (10) to the underlying part of the wrapping sheet (7) to lock a folded configuration of the transverse fin seal (10) . 5) Wrapping method according to claim 4, wherein the transverse fin seal (10) is welded to the underlying part of the wrapping sheet (7) by the sealing weld. 6) Wrapping method according to claim 3, 4 or 5 and comprising the further step of folding, in each transverse fin seal (10), at least one fin (11) protruding end of the transverse fin seal (10) against a corresponding side wall of the product and over the remaining part of the transverse fin weld (10). 7) Wrapping method according to claim 6 and comprising the further step of welding the end flap (11) to the underlying part of the wrapping sheet (7) to block a folded configuration of the end flap (11) itself. 8) Wrapping method according to claim 7, wherein the end flap (11) is welded to the underlying part of the wrapping sheet (7) by means of the sealing weld. 9) Wrapping method according to one of claims 1 to 8, wherein the longitudinal seal (9) is fin-shaped and, after its formation, is bent 90 ° against a corresponding product wall. 10) Wrapping method according to one of claims 1 to 9, wherein the transverse sealing device (49) comprises at least one sealing head (60) having a heated surface (68), which is pressed against the overlapping portions of the sheet (7) of wrapping to make a corresponding transverse weld (10) and has at least one recess (69) in correspondence with which the transverse weld (10) is interrupted to leave the vent channel (67). 11) Packaging machine (18) to make a sealed wrapping (3); the packing machine (18) includes: a wrapping station (47) in which a wrapping sheet (7) is wrapped longitudinally in a tube around a product to form a tubular wrapping; a longitudinal sealing device (48) which makes a longitudinal sealing (9) on the tubular wrapping to stabilize the shape of the tubular wrapping itself; and a transversal sealing device (49) which is arranged downstream of the longitudinal sealing device (48) and realizes a pair of transversal welds (10) which close opposite ends of the tubular wrapping in correspondence with the lateral walls of the product; the packing machine (18) is characterized by the fact that the transversal sealing device (49) is shaped to interrupt, during the execution of at least one transversal seal (10), the transversal seal (10) itself in a limited portion of the tubular wrapping in such a way as to leave, astride the transversal seal (10), a vent channel (67) that connects the inside of the sealed wrapping (3) with the foreign environment; and A closing device is provided to close, after the execution of the transverse welds (10), the vent channel (67).