CROSS-REFERENCE TO RELATED APPLICATIONS

This Patent Application claims priority from Italian Patent Application No . 102021000030179 filed on November 30 , 2021 , the entire disclosure of which is incorporated herein by reference .

TECHNICAL FIELD

The present invention relates to a method and unit to cut a wall of a pack, in particular of smoking articles .

The present invention finds advantageous application in a packing machine ( for example a cellophane wrapping machine ) for manufacturing a pack of cigarettes known as "book-pack, to which the following disclosure will make explicit reference without thereby losing generality .

PRIOR ART

A "book-pack" pack of cigarettes comprises ( at least ) two containers , which house respective wrapped groups of cigarettes , have respective open upper ends , and are hinged to one another so as to rotate between a closed configuration, in which the two containers are overlapping one another, and an open configuration, in which the two containers are separate ; furthermore , a lid is provided which is hinged to a rear container and, when in a closed position, embraces the upper part of both containers .

The production of a "book-pack" pack of cigarettes provides for the forming of the two containers by using two corresponding blanks which are folded around the respective wrapped groups of cigarettes , coupling ( overlapping) the two containers , and then folding around the two coupled ( overlapped) containers a third blank that j oins the two containers and forms the common lid . After folding the third blank, it is necessary to make a cut in the bottom wall of the "book-pack" pack of cigarettes to allow the separation of the two containers (namely to allow the two containers to rotate relative to one another ) ; normally a double cut is made ( that is , two close and parallel cuts ) to remove a flap ( strap ) from the bottom wall so as to obtain a clear separation between the two containers . For said purpose a cutting unit is used that is provided with two parallel and adj acent rotary blades , which are partially housed in a collecting chamber subj ect to suction, which should capture and remove the strap as soon as the strap has been separated from the rest of the bottom wall . However, it is not infrequent that even after the cut made by the two rotary blades , the strap remains stuck in the bottom wall and therefore is not removed by the suction; consequently, downstream of the cutting unit some "book-pack" packs of cigarettes still have the strap on the bottom which may be more or less in the original position . This can generate various problems such as the loss of the strap in the machine before applying the transparent plastic overwrap or the wrapping (with the transparent plastic overwrap ) of the strap together with the pack in completely random positions giving the final user the impression of a low- quality pack of cigarettes .

US7415812B2 describes a packing machine for manufacturing a pack of cigarettes and comprising : a first wrapping unit for forming a first wrap containing a group of cigarettes , a second wrapping unit for forming a second wrap containing another group of cigarettes , and a third wrapping unit for j oining the two wraps by means of an outer blank provided with a hinge which allows the two wraps to rotate relative to one another .

DESCRIPTION OF THE INVENTION

The obj ect of the present invention is to provide a method and a unit to cut a wall of a pack, in particular of smoking articles that allow to make the cut without undesirable consequences , in particular that allow to ensure the removal of the strap after the cut , and, at the same time , are easy and inexpensive to implement .

According to the present invention, a method and a unit to cut a wall of a pack, in particular of smoking articles , are provided, according to what is claimed in the attached claims .

The claims describe embodiments of the present invention forming an integral part of the present description .

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described with reference to the attached drawings , which illustrate a non-limiting embodiment thereof , wherein :

• Figure 1 is a perspective view of a "book-pack" pack of cigarettes in a closed configuration;

• Figure 2 is a perspective view of the pack of cigarettes of Figure 1 in an open configuration;

• Figure 3 is a view of a blank used to manufacture the pack of cigarettes of Figure 1 ;

• Figure 4 is a schematic plan view of a cutting unit to make a cut in a bottom wall of the pack of cigarettes of Figure 1 ;

• Figures 5- 8 schematically illustrate a sequence of operations carried out in the cutting unit of Figure 4 ; and

• Figure 9 is a perspective view from below of the pack of cigarettes of Figure 1 in the closed configuration and highlighting a strap being removed from the bottom wall . PREFERRED EMBODIMENTS OF THE INVENTION

In Figures 1 and 2 , number 1 denotes as a whole a "book-pack" pack of cigarettes comprising two containers 2 and 3 , which house respective wrapped groups of cigarettes , which have respective open upper ends , and are hinged to one another so as to rotate between a closed configuration ( illustrated in Figure 1 ) , in which the two containers 2 and 3 overlap one another, and an open configuration ( illustrated in Figure 2 ) , in which the two containers 2 and 3 are separated; moreover, a lid 4 is provided which is hinged to a rear container 2 and, when in a closed position, embraces the upper part of both containers 2 and 3 .

According to a preferred embodiment illustrated in the attached figures , the rear container 2 is larger and houses a larger group of wrapped cigarettes ( for example formed by two layers of seven cigarettes each) , whereas the front container 3 is smaller and houses a smaller wrapped group of cigarettes ( e . g . , formed by a single layer of six cigarettes ) ; according to a di f ferent embodiment not illustrated, the two containers 2 and 3 have the same si ze .

The production of the pack 1 of cigarettes provides for the forming of the two containers 2 and 3 by using two corresponding blanks (not illustrated) which are folded around the respective wrapped groups of cigarettes , coupling ( overlapping) the two containers 2 and 3 , and then folding a third blank 5 ( illustrated in Figure 3 ) around the two coupled ( overlapped) containers 2 and 3 which j oins the two containers 2 and 3 and forms the common lid 4 .

The pack 1 of cigarettes comprises a bottom wall 6 ( illustrated for example in Figure 3 ) which i s arranged on the outside , is part of the blank 5 , and embraces both containers 2 and 3 ; namely, the bottom walls of the two containers 2 and 3 rest against the bottom wall 6 which covers the same . As illustrated in Figure 5 , when the pack 1 of cigarettes is manufactured, the bottom wall 6 is glued only to the rear container 2 by means of a glue 7 and therefore the bottom wall 6 has no link ( constraint ) with the front container 3 . In other words , initially the bottom wall 6 of the pack 1 of cigarettes is glued only to the rear container 2 by means of the glue 7 applied only on one side and is not glued to the front container 3 .

After folding the blank 7 it is necessary to make a cut 8 ( schematically illustrated in Figure 3 ) in the bottom wall 6 of the pack 1 of cigarettes to allow the separation of the two containers 2 and 3 ( namely, to allow the two containers 2 and 3 to rotate relative to one another ) . In other words , initially the bottom wall 6 is completely intact and therefore free from any division and consequently does not allow any movement between the two containers 2 and 3 ; it is therefore necessary to make the cut 8 to divide the bottom wall 6 into two parts 9 and 10 which can be moved away from one another to allow movement between the two containers 2 and 3 .

In Figure 4 , number 11 denotes as a whole a cutting unit which, in order to make a clear separation between the two containers 2 and 3 , makes the cut 8 in the bottom wall 6 of the pack 1 of cigarettes which is fed along a straight path P . Preferably, the cutting unit 11 performs a double cut 8 in the bottom wall 6 of the pack 1 of cigarettes , namely the cut 8 is made along two parallel cutting lines spaced apart from one another and leads to the elimination, from the bottom wall 6 , of a strap B or strip ( illustrated in Figures 6 and 9 ) between the two cutting lines ( the strap B has a width of about 1 mm) ; according to an alternative embodiment , the cutting unit 11 can perform a single cut 8 in the bottom wall 6 of the pack 1 of cigarettes (namely, the cut 8 is made along a single cutting line ) . The cutting unit 11 comprises a belt conveyor 12 which feeds each pack 1 of cigarettes along a straight path P ; according to an alternative embodiment not illustrated, the conveyor 12 rotates and feeds each pack 1 of cigarettes along a circular path P .

The cutting unit 11 comprises a cutting station S I which is arranged along the path P and is provided with a cutting device 13 which makes the cut 8 in the bottom wall 6 of each pack 1 of cigarettes so as to divide the bottom wall 6 in the rear part 9 , which is arranged in the area of the rear container 2 ( and that is therefore glued to the rear container 2 by way of the glue 7 ) and in the front part 10 , which is arranged in the area of the front container 3 ( and therefore it has no connection with the front container 3 since the glue 7 is applied only in the area of the rear container 2 and therefore only between the rear container 2 and the rear part 9 ) . The cutting device 13 comprises two coaxial rotary blades at a given distance from one another which are mounted so as to rotate around the same rotation axis in order to form two parallel and separate cutting lines in the bottom wall 6 of the pack 1 of cigarettes to delimit the strap B which must subsequently be discarded .

The cutting station S I is also provided with a sucking device 14 which is configured to suck (namely remove by means of aspiration) the strap B that is separated by the cutting device 13 by means of the double cut 8 (namely along two parallel and separate cutting lines ) . The sucking device 14 comprises a sucking duct (namely, connected to a suction source ) designed to suck up the strap B which is separated by the cutting device 13 ; the function of the sucking duct 14 is to convey by suction the strap B which has been separated from the bottom wall 6 so as to convey the strap B into a suitable collecting area (not illustrated) . By way of example , the suction in the sucking duct of the sucking device 14 can be made by using an impeller or a flow accelerator . According to a possible embodiment , an initial end of the sucking duct of the sucking device 14 has a conical shape having the minimum dimension in the area of the cutting device 13 ( namely, having a dimension which progressively widens moving away from the cutting device 13 so as to have the maximum vacuum near the cutting device 13 ) .

As the cutting device 13 makes the cut 8 of the bottom wall 6 of the pack 1 of cigarettes , the rear part 9 of the bottom wall 6 remains in its initial position as it is stably glued to the rear container 2 by way of the glue 7 ; whereas , as the cutting device 13 makes the cut 8 of the bottom wall 6 of the pack 1 of cigarettes , the front part 10 of the bottom wall 6 tends to rise by elastic return with respect to the front container 3 to which it is not in any way constrained ( as previously mentioned, no glue is initially applied between the front part 10 and the front container 3 ) and this li fting of the front part 10 substantially helps the removal of the strap B as it prevents the strap B from being stuck between the two parts 9 and 10 .

The sucking action generated by the sucking device 14 obviously also has an ef fect on the front part 10 of the bottom wall 6 and contributes in li fting the front part 10 from the front container 3 ; namely, also the front part 10 of the bottom wall 6 is af fected by the suction applied by the sucking device 14 and said suction (pulling the front part 10 of the bottom wall 6 into the sucking device 14 ) contributes in li fting the front part 10 from the front container 3 . The sucking action generated by the sucking device 14 obviously also af fects the rear part 9 of the bottom wall 6 , but the rear part 9 is glued to the rear container 2 and therefore does not move .

According to a possible embodiment , the cutting station S I can also comprise a blower device 15 which directs a compressed j et of air towards the front part 10 of the bottom wall 6 which forces the front part 10 to li ft (namely, forces the front part 10 to move away from the front container 3 and from the rest of the bottom wall 6 ) ; the function of the blower device 15 is to help the li fting of the front part 10 of the bottom wall 6 after having made the double cut 8 so as to increase the ef fect of the natural elastic return of the front part 10 .

It is important to observe that the blank 5 ( illustrated in Figure 3 ) is originally completely flat and is subsequently folded around the two containers 2 and 3 ; therefore , in the absence of an outer constraint , namely, i f left free , the various portions of the blank 5 ( including the front part 10 of the bottom wall 6 ) tend to move naturally towards the original flat configuration by elastic return . Consequently, after making the double cut 8 , the front part 10 of the bottom wall 6 is free from mechanical constraints and therefore by elastic return it tends spontaneously to move away from the front container 3 and therefore from the rest of the bottom wall 6 (namely from the rear part 9 of the bottom wall 6 ) . The blower device 15 can be provided to accentuate by means of a compressed j et of air ( and in addition to the action of the sucking device 14 ) the spontaneous tendency of the front part 10 of the bottom wall 6 to move away from the front container 3 .

The moving away of the front part 10 of the bottom wall 6 from the front container 3 and therefore from the rest of the bottom wall 6 (namely, from the rear part 9 of the bottom wall 6 ) is essential to " l eave- free" the strap B generated by the double cut 8 as it prevents the strap B from getting stuck between the two parts 9 and 10 of the bottom wall 6 ; once the strap B is no longer held between the two parts 9 and 10 of the bottom wall 6 , its removal by means of suction is very simple and reliable .

The cutting unit 11 comprises a separation station S2 which is arranged along the path P downstream of the cutting station S I and is provided with a folding device 16 which folds the front part 10 of the bottom wall 6 of each pack 1 of cigarettes so as to move the front part 10 away from the rest of the bottom wall 6 (namely, from the rear part 9 ) . Typically, the folding device 16 folds the front part 10 of the bottom wal l 6 of each pack of cigarettes 1 by about 90 ° to arrange the front part 10 approximately perpendicular to the rear part 9 ( as illustrated in Fig . 7 ) . The folding device 16 exploits the natural elastic return of the front part 10 of the bottom wall 6 which tends to spontaneously move the front part 10 away from the rest of the bottom wall 6 (namely, from the rear part 9 ) and comprises a fixed folding helix which pushes the front part 10 of the bottom wall 6 away from the rest of the bottom wall 6 . The folding device 16 can also comprise a blower which pushes the front part 10 of the bottom wall 6 away from the rest of the bottom wall 6 by means of a compressed j et of air .

The cutting unit 11 comprises a gluing station S3 which is arranged along the path P downstream of the separation station S2 and is provided with a gluing device 17 which applies glue 18 on the front part 10 of the bottom wall 6 of each pack 1 of cigarettes ( as also illustrated in Figure 7 ) ; the glue 18 can be applied in the form of separate glue dots or in the form of one or more continuous glue strips . The glue 18 can be hot ( therefore fast-setting) , cold ( therefore vinyl-based with slower setting) or a combination of hot glue and cold glue . In the preferred embodiment illustrated in the attached figures , the glue 18 is applied to the front part 10 of the bottom wall 6 ; according to a di f ferent embodiment , the glue 18 is applied to the bottom wall of the front container 3 ( the important thing is that , ultimately, the glue 18 is interposed between the front part 10 of the bottom wall 6 and the bottom wall of the front container 3 ) .

The cutting unit 11 comprises a folding station S4 which is arranged along the path P downstream of the gluing station S3 and is provided with a folding device 19 which folds the front part 10 of the bottom wall 6 of each pack 1 of cigarettes against the front container 3 causing the front part 10 of the bottom wall 6 to return to the initial position ( as illustrated in Figure 8 ) it had before the cutting station S I and above all before the separating station S2 . In the folding station S4 the front part 10 of the bottom wall 6 of each pack 1 of cigarettes rests and is therefore glued, by way of the glue 18 , to the front container 3 completing ( concluding) the manufacturing of the pack 1 of cigarettes . The folding device 19 can comprise a fixed folding hel ix which pushes the front part 10 of the bottom wall 6 against the rest of the pack of cigarettes 1 (namely against the front container 3 ) .

According to a possible embodiment , the cutting unit 11 comprises , furthermore , a control station which could be arranged along the path P downstream of the folding station S4 (but could also be arranged in any other position between the cutting station S I and the folding station S4 ) and is provided with a viewing device which, by acquiring and analysing one or more images of the pack 1 of cigarettes , is able to establish whether the strap B produced by the double cut 8 has been correctly eliminated . Obviously, any packs 1 of cigarettes that do not conform to the desired speci fications (namely, in which the strap B produced by the double cut 8 has not been correctly eliminated) would be discarded in a discard station arranged downstream of the control station ( even outside the cutting unit 11 ) .

The embodiments described herein can be combined with one another without departing from he scope of the present invention .

The cutting unit 11 described above has numerous advantages . In the first place , the cutting unit 11 described above allows to ensure the removal of the strap B after the double cut 8 avoiding that the strap B ( or a piece of the strap B ) can remain in contact with the bottom wall 6 of the pack 1 of cigarettes ; this result is obtained due to the fact that after the double cut 8 the front part 10 of the bottom wall 6 moves away from the rear part 9 o f the bottom wall 6 , thus freeing the strap B (namely, preventing the strap B from remaining " trapped" between the two walls 9 and 10 of the bottom wall 6 ) . Namely, by separating the front part 10 of the bottom wall 6 from the rear part 9 of the bottom wall 6, the strap B produced by the double cut 8 is surely moved away from the bottom wall 6 and therefore easily removed and consequently the correct removal of the strap B produced by the double cut 8 is ensured, thus avoiding that the strap B ( or a piece of the strap B ) can remain in contact with the bottom wall 6 of the pack 1 of cigarettes .

Furthermore , the cutting unit 11 described above is simple and inexpensive to implement since , compared to a similar known cutting unit , it requires modi fications that are quick to make using commercial pieces or pieces that can be easily obtained with standard machining .

The cutting unit 11 described above allows the cut 8 of the bottom wall 6 to be made in a very precise and accurate way, always ensuring optimal functionality of the pack 1 of cigarettes .

Finally, the cutting unit 11 described above also allows the cut 8 to be made singularly, since the subsequent " opening" of the front part 10 of the bottom wall 6 always ensures a complete separation between the two parts 9 and 10 of the bottom wall .

LIST OF REFERENCE NUMBERS OF THE FIGURES

1 pack of cigarettes

2 rear container 3 front container

4 lid

5 blank

6 bottom wall

7 glue

8 cut

9 back part

10 front part

11 cutting unit

12 conveyor

13 cutting device

14 sucking device

15 blower device

16 folding device

17 gluing device

18 glue

19 folding device B strap P path

S I cutting station

S2 separation station

S3 gluing station

S4 folding station