CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application claims priority from Italian patent application no. 102018000005628 filed on 23/05/2018, the entire disclosure of which is incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a forming unit for groups of filter cigarettes, in said filter at least one object is embedded.

The present invention finds advantageous application to the feeding of filter cigarettes, in which the filter is provided with a frangible capsule containing an aromatic substance, to which the following description will explicitly refer without thereby losing generality.

PRIOR ART

Filter cigarettes have been on the market for some years, in which the filter is provided with a frangible capsule containing a liquid aromatic substance; the smoker can, at will, crush (with more or less force) the filter to break the capsule and allow the aromatic substance to flow out and diffuse into the filter.

During the production of filters provided with frangible capsules, it is necessary to perform a control on the presence and integrity of the frangible capsules, since the frangible capsules may be absent or, more frequently, damaged.

Currently the controls on frangible capsules are carried out during the filter manufacturing step or immediately upstream or immediately downstream of the connection of the filter with the cigarette. However, it may happen that during the subsequent handling and packing of the filter cigarettes, the frangible capsules can be damaged for example by the formation of micro-fractures, with a consequent outflow (even over relatively long periods of time) of the aromatic substance. Consequently, it is not infrequent that the final user, after the purchase of the pack of cigarettes, can find, on the inside thereof, filter cigarettes having a damaged frangible capsule and therefore the liquid inside has flowed out completely into the filter of the cigarette and dried (therefore even if the final user exerts pressure on the filter, said action would have no effect as the frangible capsule no longer contains the aromatic substance). Patent application EP1772067A1 describes a forming unit for groups of filter cigarettes. The forming unit comprises: a feeding hopper, which is provided, at the bottom, with at least one output mouth from which a group of cigarettes is extracted; a forming conveyor which is arranged in front of the output mouth of the feeding hopper and is provided with a plurality of pockets inside which the groups of filter cigarettes are fed; a control unit which is arranged along the forming conveyor and faces the pockets; and a rejection element which is arranged along the forming conveyor downstream of the control unit and is designed to remove a group of filter cigarettes to be rejected from a pocket. The control unit comprises three microwave sensors designed to check the tobacco filling degree of the tip of each filter cigarette housed in a pocket while the pocket moves in front of a corresponding microwave sensor.

Patent application EP0100537A2 describes a forming unit for groups of filter cigarettes. The forming unit comprises: a feeding hopper, which is provided, at the bottom, with at least one output mouth from which a group of cigarettes is extracted; a plurality of channels within which the filter cigarettes are conveyed; a plurality of control units, each of which is arranged in a corresponding channel and is designed to carry out a control on the filter cigarettes coming down along the channel; and a plurality of rejection elements, each of which is arranged in a corresponding channel downstream of the control unit and is designed to remove a filter cigarette to be rejected from the channel. Each control unit comprises a (preferably optical) sensor designed to check the tobacco filling degree of the tip of each filter cigarette coming down along the corresponding channel.

DESCRIPTION OF THE INVENTION

The object of the present invention is to provide a forming unit for groups of filter cigarettes, at least one object is embedded in said filter, the which forming unit of groups is free from the drawbacks described above and, at the same time, is easy and inexpensive to implement. According to the present invention a forming unit for groups of filter cigarettes is provided, in said filter at least one object is embedded, according to what is established in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

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

- Figure 1 illustrates a schematic sectional view of a forming unit for groups of filter cigarettes which is made according to the present invention and is part of a cigarette packing machine;

- Figure 2 illustrates a schematic and sectional view of an alternative embodiment of the unit for forming groups of cigarettes of Figure 1 ;

- Figure 3 illustrates an enlarged view of a detail of Figure 1 and of Figure 2;

- Figure 4 illustrates a view on an enlarged scale of a rejection element of the unit for forming groups of cigarettes of Figure 1 or of the unit for forming groups of cigarettes of Figure 2; and

- Figure 5 illustrates a schematic front view, on an enlarged scale, of a conveyor for forming groups of cigarettes.

PREFERRED EMBODIMENT OF THE INVENTION

Number 1, in Figure 1, denotes as a whole a unit for forming groups of filter cigarettes 2, in which at least one frangible aromatic capsule 3, (schematically illustrated in

Figures 3 and 4) containing on the inside an aromatic substance in liquid form, is embedded therein. The forming unit 1 is part of a cigarette packing machine which produces packs of cigarettes by folding an inner wrapping sheet of metallised paper and then an outer wrapping sheet around each group of cigarettes formed by the forming unit 1.

The forming unit 1 for groups of cigarettes, according to the embodiment illustrated in Figure 1, is provided with a feeding hopper 4 inside which the filter cigarettes 2 are fed. The feeding hopper 4 is provided, at the bottom, with at least one output mouth from which a group of filter cigarettes 2 is extracted.

The filter cigarettes 2 coming from the feeding hopper 4 are conveyed by gravity to inside a plurality of substantially vertical channels 5 along which the filter cigarettes 2 are coming down by gravity. The channels 5 form part of the feeding hopper 4 and are designed to separate the flow of filter cigarettes 2.

A control unit 6 is arranged at each channel 5. The control unit 6 performs a control on the filter cigarettes 2 that are coming down along the channel 5. Each control unit 6 comprises a microwave sensor 7 which is configured to check the presence and/or integrity of the aromatic capsule 3 embedded in the filter of the filter cigarette 2 coming down along the corresponding channel 5. The microwave sensors 7 of the adjacent channels 5 can be arranged vertically aligned or vertically offset. By vertically offsetting the microwave sensors 7, it is possible to ensure with greater security that the adjacent microwave sensors 7 do not interfere one with the other and therefore that the measurement of the presence and/or integrity of the aromatic capsule

3 is not altered.

Each control unit 6 can further comprise a sensor 8 for controlling the tips of the filter cigarettes 2 on the opposite side of the filter (i.e. where the tobacco is visible). Each sensor 8 is arranged on the opposite side of the microwave sensor 7. In other words, each sensor 8 is arranged facing the filter cigarette 2 on the opposite side relative to the filter, i.e. it is arranged on the tobacco side. Each sensor 8 controls the tip of the filter cigarettes 2, so as to check the correct filling thereof. That is, each sensor 8 checks the presence of tobacco in the tip of the filter cigarette 2 on the opposite side of the filter. Each sensor 8 for controlling the tips of the filter cigarettes 2 is preferably optical but could also be a sensor of a different type.

The controlled filter cigarettes 2 continue their path along the corresponding channel 5 up to a rejection element 9. Each rejection element 9 is arranged along the corresponding channel 5 and downstream of the control unit 6. Each rejection element 9 is designed to eliminate the filter cigarettes 2 to be rejected, i.e. the filter cigarettes

2 that the corresponding control unit 6 has established to be defective (for example due to lack or incomplete filling of the corresponding capsule 3 embedded in the filter). Each rejection element 9 can carry out the rejection in the axial direction or in a transverse direction relative to the longitudinal axis of the filter cigarette 2.

Figure 4 illustrates a possible embodiment of a rejection element 9 which transversely removes the filter cigarettes 2. The removed filter cigarette 2 is fed to a rejection duct 10, so as to move it away from the corresponding channel 5. The removal of the filter cigarette 2 can take place with the aid of a blowing member such as a compressed air nozzle, or with the aid of a mechanical pusher.

The filter cigarettes 2 which are suitable, continue on their path along the corresponding channels 5 up to the output mouth of the feeding hopper 4, from which the groups of filter cigarettes 2 are cyclically extracted. Each group of filter cigarettes 2 is then inserted into a corresponding pocket 11 of a forming conveyor 12 to continue its path towards the wrapping units.

Figure 2 illustrates a second and different embodiment of the group forming unit 1. Substantially, in this embodiment the channels 5 are made at a control device 13 which is arranged upstream of the feeding hopper 4. In other words, instead of carrying out the control in the feeding hopper 4, as it occurs in the embodiment described above, according to the present embodiment the control is carried out upstream of the feeding hopper 4 and at the control device 13.

According to this embodiment, the filter cigarettes 2 are initially fed to a control hopper 14 inside which the filter cigarettes 2 are fed. Subsequently, the filter cigarettes 2 are conveyed by gravity towards the control device 13 which is arranged downstream of the control hopper 14. The control device 13 comprises the plurality of channels 5. A control unit 6 is arranged at each channel 5. Each control unit 6 comprises the microwave sensor 7 which is configured to check the presence and/or integrity of the aromatic capsule 3 embedded in the filter of the filter cigarette 2. In addition, each control unit 6 can also comprise the sensor 8 for controlling the tips of the filter cigarettes 2. The rejection element 9 is arranged along each channel 5 and downstream of the control unit 6 to remove any defective filter cigarettes 2.

The feeding hopper 4 is arranged downstream of the control device 13.

Advantageously, an intermediate storage unit is arranged between the control hopper 14 and the feeding hopper 4, in which the filter cigarettes 2 are mass-housed (i.e. without elements for separating the filter cigarettes 2 so that the filter cigarettes 2 are free to move even horizontally so as to mix one with the other). The intermediate storage unit performs a continuous and uniform flow of filter cigarettes 2.

Alternatively, it is the feeding hopper 4 which acts as an intermediate storage unit. In the embodiment illustrated in Figure 1 , the channels 5 in which the control and the rejection of the filter cigarettes 2 are carried out are an integral part of the feeding hopper 4, while in the embodiment illustrated in Figure 2, the channels 5 in which the control and the rejection of the filter cigarettes 2 are carried out are an integral part of the control hopper 14, which is separated from the feeding hopper 4 and is arranged upstream of the feeding hopper 4. Therefore, in the embodiment illustrated in Figure 2 the channels of the feeding hopper 4 are devoid of the control unit 6 and are simply designed to singularize the flow of the filter cigarettes 2 coming from the control hopper 14.

Advantageously, as illustrated in Figure 3, each microwave sensor 7 comprises an emitter element 15 and a receiver element 16 which face each other. In other words, the emitter element 15 emits microwaves which generate a measurement field within which the filter cigarettes 2 pass. The electromagnetic waves are then received by the receiver element 16. In this way, through the obtained signal, in particular as a function of the frequency and the amplitude of the resonance curve, the information concerning the wellbeing, i.e. integrity, of the aromatic capsule 3 can be extrapolated.

According to a possible embodiment, each microwave sensor 7 comprises a resonant chamber in which the emitter element 15 and the receiver element 16 are arranged. The resonant chamber of each microwave sensor 7 is characterized by a reference vacuum resonance curve which has its own behaviour and its own resonance frequency. Depending on the material that is introduced into a resonant chamber, the resonance curve remains unchanged and can be simply translated to a lower resonance frequency (typical behaviour when materials that do not absorb electromagnetic waves are introduced into the resonant chamber); alternatively, the resonance curve can be modified, translated at a lower resonance frequency and with the reduced maximum amplitude (typical behaviour when materials that absorb electromagnetic waves are introduced into the resonant chamber).

According to a preferred embodiment, the microwave sensor 7 is flat.

The control of the filter cigarettes 2 can take place both with the filter cigarettes 2 stationary, and with the filter cigarettes 2 in movement (preferably not too fast). To prevent the filter cigarettes 2 from passing through the corresponding microwave sensor 7 too quickly, for example due to a downstream reject of one or more filter cigarettes 2, it is possible to arranged a locking element 17 (schematically illustrated in Figure 3). The locking element 17 is configured to intercept the flow of filter cigarettes 2 inside the respective channels 5, so that the filter cigarettes 2 have a predetermined speed or are stationary at the microwave sensor 7 and at the sensor 8, if present. In particular, the locking element 17 could be configured as a transversely translating element, namely, along a direction perpendicular to the longitudinal axis of the channels 5.

According to a preferred embodiment, the channels 5 are made by means of perfectly vertical dividing walls (as illustrated in Figure 2) or substantially vertical (or slightly inclined relative to the vertical direction as illustrated in Figure 1); each channel 5 is delimited by two corresponding dividing walls.

According to an alternative embodiment not illustrated, each channel 5 is laterally delimited by at least one motor-driven belt provided with seats inside which the filter cigarettes 2 are housed. In this way, the conveying speed of the belt establishes the speed with which the filter cigarettes 2 are conveyed through the channel 5. Alternatively, each channel 5 is delimited, on one side, by a motor-driven belt and on the opposite side by a dividing wall or each channel 5 is delimited on both sides by two different motor-driven belts.

According to a further embodiment not illustrated, each channel 5 is delimited, on one side, by an outer surface of a motor-driven conveying drum provided with seats in which the filter cigarettes 2 are housed and on the opposite side by a dividing wall shaped like an arc of circumference which is complementary to the outer surface of the conveying drum.

According to a possible embodiment illustrated in Figure 5, the forming unit 1 comprises a further control unit 18 arranged at the forming conveyor 12. The control unit 18 faces the pockets 11 and comprises at least a microwave sensor 19 which checks the presence and/or integrity of the capsule 3 embedded in the filter of each filter cigarette 2 housed in a pocket 11 ; preferably, the control unit 18 comprises for each layer of filter cigarettes 2 of the group of filter cigarettes 2 a corresponding microwave sensor 19 and therefore, in the embodiment illustrated in Figure 5, the control unit 18 comprises three microwave sensors 19 arranged at different heights and each aligned with a corresponding layer of filter cigarettes 2 of the group of filter cigarettes 2.

The control is carried out while the pocket 11 moves in front of the microwave sensor 19. In the case in which at least one filter cigarette 2, in which the capsule 3 is not present or intact, is detected in a group of cigarettes 2, the group of filter cigarettes 2 is removed from the pocket 11 by a rejection element arranged along the forming conveyor 12 downstream of the control unit 18.

Alternatively, it is conceivable that the control of the presence and/or integrity of the capsule 3 embedded in the filter of each filter cigarette 2 is carried out only and exclusively at the forming conveyor 12 by the control unit 18, i.e. that only the control unit 18 is present and instead the control unit 6 is not present. More frequently, however, only the control unit 6 is present and instead the control unit 18 is absent.

In the embodiment described above, only one capsule 3 is embedded in the filter of each filter cigarette 2; according to an alternative embodiment, within the filter of each filter cigarette 2, more than one capsule 3 can be embedded.

The invention as described can advantageously be applied to the control of any object (other than a frangible capsule containing an aromatic substance in liquid form) which can be embedded within the filter of the cigarette 2.

The forming unit 1 for groups of filter cigarettes 2 described up to now has a plurality of advantages.

Mainly, the forming unit 1 for groups of cigarettes described above allows the control of the capsules 3 in the filters of the filter cigarettes 2 at the last useful moment, or immediately before packing (once a group of filter cigarettes 2 has been wrapped, it is no longer possible to perform any control on filter cigarettes 2). Therefore, the probability of damaging the capsules 3 downstream of the control of the capsules 3 is very low.

In the embodiment illustrated in Figure 2, the individual channels 5 can be spaced apart one from the other by a distance that is not correlated with the size of the pack of cigarettes (i.e. of the group of cigarettes contained in the pack of cigarettes); moreover, also the number of channels 5 does not depend on the pack of cigarettes (i.e. the group of cigarettes contained in the pack of cigarettes) to be implemented. In other words, in the embodiment illustrated in Figure 2, the number, arrangement and/or size of the channels 5 are dimensioned solely according to the control requirements.

The forming unit 1 for groups of cigarettes described above is compatible with any existing packing machine (i.e. it is possible to“ upgrade” an existing packing machine by inserting the forming unit 1 for groups of cigarettes described above into the packing machine.