WO2019097428A1

WO2019097428A1 - Unit and method for the inspection of a group of portions of tobacco industry articles

Info

Publication number: WO2019097428A1
Application number: PCT/IB2018/058967
Authority: WO
Inventors: Giuliano Gamberini; Marco Esposti; Massimo Sartoni; Luca Federici
Original assignee: G.D Società per Azioni
Priority date: 2017-11-14
Filing date: 2018-11-14
Publication date: 2019-05-23
Also published as: EP3709826A1; EP3709826B1; PL3709826T3; WO2019097428A8; CN111295103B; CN111295103A

Abstract

Unit (12) and method for the inspection of a group (3) of portions (4) of tobacco industry articles; a seat (16) which is adapted to house the group (3) of portions (4) is advanced along a path (P), which extends between an input station (SI) and an output station (S2); and an image of the group (3) of portions (4) is captured in the area of an inspection station (S3). In the input station (SI) and in the output station (S2) the group (3) of portions (4) is in a first configuration, in which the portions (4) are axially aligned in end to end contact with one another; and in the group (3) of portions (4) a relative movement is caused between the portions (4) upstream of the inspection station (S3), so that in the area of the inspection station (S3), the group (3) of portions (4) is in a second configuration, in which at least one portion (4) is not aligned with and/or spaced apart from the other portions (4).

Description

"UNIT AND METHOD FOR THE INSPECTION OF A GROUP OF PORTIONS OF

TOBACCO INDUSTRY ARTICLES"

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application claims priority from Italian patent application no. 102017000129645 filed on 14/11/2017, the entire disclosure of which is incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a unit and to a method for the inspection of a group of portions of tobacco industry articles.

The present invention finds advantageous application in a manufacturing machine for the production of combined filters for cigarettes, to which the following disclosure will make explicit reference without thereby losing generality.

PRIOR ART

A manufacturing machine, known for example from the patent EP2145551B1, for the production of combined filters for cigarettes normally comprises a combining unit which creates groups of filter portions, each of which comprises at least two different filter portions axially aligned in end to end contact with one another. Furthermore, the manufacturing machine comprises a wrapping unit which receives a succession of groups of filter portions from the combining unit, wraps a wrapping material strip around the succession of groups of filter portions so as to form a continuous filter rod, and finally separates the combined filters from the continuous filter rod by means of a cyclic transverse cut of the filter rod. The manufacturing machine comprises, furthermore, a transfer unit which transfers the groups of filter portions from the combining unit, in which the groups of filter portions are fed transversely (i.e. perpendicularly to their longitudinal axis), to the wrapping unit, in which the groups of filter portions are fed axially (i.e. parallel to their longitudinal axis) .

The combining unit comprises a number of feeding stations, which are structurally similar to one another and each of which feeds respective filter portions so as to form the groups of filter portions. Each feeding station comprises an upper hopper, which houses a mass of respective filter portions, and a series of drums arranged in cascades, the first of which picks up the filter portions from the bottom of the hopper in succession. The combining unit comprises, furthermore, a plurality of combining drums, in which the filter portions, received from a final drum of the aforementioned series of drums arranged in cascades, are combined with one another so as to form respective groups of filter portions.

A felt need within the tobacco industry is the measurement of the length of the individual filter portions forming the groups of filter portions; this requirement arises from the fact that the transversal cut of the filter rod is obtained by means of a cutting unit configured to operate the cut according to a pre set (nominal) length of the individual group of filter portions and any variations in the length of the individual group of filter portions, deriving from the variation in length of one or more filter portions comprised in the group of filter portions, involves a misalignment between the cutting unit and the groups of filter portions inside the filter rod thus causing an incorrect transverse cut (i.e. in the wrong position) of the filter rod. Moreover, any variations in length of one or more filter portions could also affect the wrapping of the wrapping material strip around the portions themselves, given that the overlapping of the strips of the wrapping material strip around the portions could be not optimal.

Patent application EP3085253A1 describes an inspection unit for a multi-segment filter portion in a manufacturing machine for the production of filters comprising a continuously driven forming belt for conveying a wrapping material strip that is placed on top of a forming belt; a series of filter portions is fed on top of the wrapping material strip to be subsequently wrapped, by the wrapping material strip itself, and thus forming a continuous multi-segment rod. The manufacturing machine furthermore comprises an inspection unit which optically detects (i.e. by means of a video camera) the segments immediately before the wrapping with the wrapping material strip so as to determine the axial position and/or the length of the individual filter portions. This known inspection unit has some drawbacks, as the various filter portions, which seamlessly follow each other, all have the same colour (in fact they are all more or less white) and the same shape and therefore when analysing an image captured by a camera it is not always possible to distinguish, with the necessary precision, the beginning and/or the end (i.e. the ends) of the individual filter portions; consequently, it is not always possible to accurately measure the length of each filter portion .

In the patent application DE102015105368 A1 an inspection unit is described for the optical control (i.e. by means of a video camera) of the length of a group of filter portions axially aligned and wrapped in a wrapping material strip (and therefore not directly visible from the outside) ; so as to allow the measurement of the length of an end filter portion (as already said not directly visible from the outside due to the presence of the wrapping material strip) , the end filter portion is temporarily (and slightly) spaced apart from other filter portions by means of mechanical or pneumatic means which cause a temporary deformation of the group of filter portions for the time necessary to capture an image. This inspection unit has some problems, since the temporary deformation of the group of filter portions wrapped by the wrapping strip can cause partial or total breakage of the wrapping strip, affecting the quality of the article and therefore leading to an increase in production waste. Moreover, the measurement of the length of several filter portions cannot be carried out simultaneously, but can only be carried out on the filter portion spaced apart at that moment.

DESCRIPTION OF THE INVENTION

The object of the present invention is to provide a unit and a method for the inspection of a group of portions of tobacco industry articles which overcomes the drawbacks of the prior art mentioned above.

In particular, the object of the present invention is to provide a unit and a method for the inspection of a group of portions of tobacco industry articles (in particular, of a multi-segment filter for cigarettes) capable of accurately detecting the length of each portion, even if the portions have a similar colour and/or shape.

Furthermore, the object of the present invention is to provide a unit and a method for the inspection of a group of portions of tobacco industry articles capable of detecting, possibly even simultaneously, the length of each portion, without damage.

According to the present invention, a unit and a method for the inspection of a group of portions of tobacco industry articles are provided, comprising the technical characteristics indicated in one or more of the appended claims .

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

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described with reference to the accompanying drawings, which illustrate an example of a non limiting embodiment, wherein:

- Figure 1 is a perspective schematic view with parts removed for clarity, of a part of a multi-segment filter manufacturing machine provided with an inspection unit made according to the present invention;

- Figures 2, 3 and 4 are, respectively, a front, perspective and plan view of the inspection unit of Figure 1;

- Figure 5 is a flat development of a drum of the inspection unit of Figure 1;

- Figures 6a and 6b illustrate a same group of filter portions before and after the execution of an axial separation performed, respectively, in the inspection unit of Figure 1;

- Figures 7a and 7b illustrate a same seat of a drum of the inspection unit of Figure 1 before and after the execution of an axial separation; and

- Figures 8a and 8b illustrate a same group of filter portions before and after the execution of a radial separation performed, respectively, in an alternative embodiment of the inspection unit of Figure 1.

PREFERRED EMBODIMENTS OF THE INVENTION

In Figure 1, number 1 denotes, as a whole, a manufacturing machine for the production of combined filters 2 for cigarettes, each of which comprises a group 3 of filter portions 4 wrapped in a sheet of wrapping material folded into a tube shape and stabilized by gluing.

The manufacturing machine 1 comprises a combining unit 5 which creates the groups 3 of filter portions 4 so that each group 3 comprises a plurality of different filter portions 4 axially aligned in end to end contact with one another. According to the (non-limiting) embodiment illustrated in the annexes, each group 3 comprises five filter portions 4; according to other embodiments not illustrated the number of filter portions 4 in each group 3 is different (for example two, three, four, six

Furthermore, the wrapping machine 1 comprises a wrapping unit 6 which receives a succession of groups 3 of filter portions 4 from the combining unit 5, a wrapping material strip, to form a continuous filter rod, is wrapped around the succession of groups 3 of filter portions 4 and finally, separates the individual filters 2 from the continuous filter rod by means of a cyclic transverse cut of the continuous filter rod itself. The wrapping unit 6 is of the double-line type and comprises a frame which supports a horizontal forming beam provided with two parallel grooves, inside each, a respective strip of wrapping material is wrapped around a continuous succession of groups 3 of filter portions 4 provided with end to end contact and advancing in a direction parallel to their longitudinal axis, for forming a continuous filter rod.

The wrapping machine 1 comprises, furthermore, a transfer unit 7 which transfers the groups 3 of filter portions 4 from the combining unit 5, in which the groups 3 of filter portions 4 are fed transversely (i.e. perpendicularly to their central axis) to the wrapping unit 6, in which the groups 3 of filter portions 4 are fed axially (i.e. parallel to their central axis) .

The combining unit 5 comprises a structure supporting three units 8 for feeding the filter portions 4, which are structurally similar to each other and each of which feeds respective filter portions 4 so as to form the groups 3 of filter portions 4. Each unit 8 for feeding the filter portions 4, comprises an upper hopper 9, which houses a mass of respective filter portions 4 of multiple length with respect to the final length, and a pick up drum which picks up, in succession, the filter portions 4 from the bottom of the hopper 9 and cooperates with a pair of cutting drums provided with respective circular blades for carrying out the transversal cut of the filter portions 4, so as to obtain the desired length of the filter portions 4. Furthermore, each unit 1 for feeding the filter portions 4 comprises a series of alignment drums, which receive the cut filter portions 4 and perform the correct alignment of the filter portions 4. Each unit 8 for feeding the filter portions 4 further comprises an insertion drum 10 which receives the groups 3 of filter portions 4 from a previous unit 8 for feeding the filter portions 2 or, in the case of the first feeding unit 8, creates groups 3 of filter portions 4; in the insertion drum 10, the filter portions 4, received from a final alignment drum, are inserted into respective groups 3 of filter portions 4. Finally, each feeding unit 8 comprises an output drum 11, which receives the groups 3 of filter portions 4 from the insertion drum 10 and transfers the groups 3 of filter portions 4 to the next feeding unit 8 or, in the case of the last feeding unit 8, to the transfer unit 7.

The manufacturing machine 1 comprises an inspection unit 12 (only schematically illustrated in Figure 1 and better illustrated in Figures 2, 3 and 4) which is arranged between the combining unit 5 and the wrapping unit 6 (i.e. downstream of the combining unit 5 and upstream of the wrapping unit 6) . In the (non-limiting) embodiment illustrated in Figure 1, the inspection unit 12 is located close to the transfer unit 7 and immediately upstream of the transfer unit 7. The inspection unit 12 checks each group 3 of filter portions 4 for detecting (measuring) the actual length of at least one of the portions 4 forming the group 3 of filter portions 4 prior to the wrapping with the wrapping material strip; therefore, this check is performed when the group 3 of filter portions 4 is still "naked", i.e. not wrapped in the corresponding sheet of wrapping material .

According to what is illustrated in Figures 2-5, the inspection unit 12 comprises a transport device 13 provided with a drum 14 which rotates with a continuous motion (anti-clockwise in Figure 2) around a central rotation axis 15 and a plurality of seats 16, which are uniformly distributed along the periphery of the drum 14 and are each adapted to house a group 3 of portions 4. The seats 16 are of the suction type, i.e. they hold the portions 4 of the groups 3 by suction; in particular, each seat 16 comprises a plurality of suction holes which are in pneumatic communication with a suction source. The rotation of the drum 14 around the rotation axis 15 cyclically moves each seat 16 between a path P having a circular shape, which extends between an input station SI in which the empty seat 16 receives a group 3 of portions 4 and a subsequent output station S2 in which the seat 16 releases the group 3 of portions 4 previously received.

The inspection unit 12 comprises an optical device 17 which is arranged along the path P at an inspection station S3, which is located between the input station SI and the output station S2. The optical device 17 normally comprises a camera and an illuminator which cooperate together so as to capture (at least) an image of each group 3 of portions 4 while the group 3 of portions 4 transits through the inspection station S3 supported by a corresponding seat 16 of the drum 14.

In the input station SI (i.e. as input into the drum 14) and in the output station S2 (i.e. as output from the drum 14) each group 3 of portions 4 is in a standard configuration (illustrated in Figure 6a) in which the portions 4 are axially aligned in end to end contact with one another (i.e. the group 3 of portions 4 is configured to be wrapped in the corresponding sheet of wrapping material and thus become a combined filter 2) .

The inspection unit 12 comprises moving means 18 (illustrated in Figures 7a and 7b) which are coupled to the transport device 13 (i.e. to the drum 14) so as to cause, in each group 3 of portions 4, a first relative movement between the portions 4 upstream of the inspection station S3, so that, at the inspection station S3 the group 3 of portions 4 is in an exploded configuration (illustrated in Figure 6b and in Figure 7b) in which at least one portion 4 is misaligned with and/or spaced apart from the other portions 4 (in the embodiment illustrated in Figure 6b and in Figure 7b, the two side portions 4 are axially spaced apart from the other three central portions 4) . In this way, in the inspection station S3 the optical device 17 can capture an image of each group 4 of portions 3 when the group 4 of portions 3 is at least partially " exploded", i.e. when there is a given distance other than zero between at least one portion 4 and the other portions 4; this distance other than zero between at least one portion 4 and the other portions 4 allows to identify, in the image and with extreme precision, the ends of the portion 4 separated from the other portions 4 and consequently allows to measure with extreme precision, as well, the actual length (axial dimension) of the separate portion 4. In other words, even if the portions 4 all have the same colour, the distance other than zero between at least one portion 4 and the other portions 4 creates an obviously different "hole" of colour which highlights the ends of the portions 4 and therefore allows to identify in the image and with extreme precision the ends of the portion 4 separated from the other portions 4.

It is important to note that the inspection unit 12 is arranged between the combining unit 5 and the wrapping unit 6 (i.e. downstream of the combining unit 5 and upstream of the wrapping unit 6) and therefore in the inspection unit 12 each group 3 of portions 4 is without the corresponding wrapping sheet and therefore without the elements which join the portions 4 together; consequently, in the inspection unit 12 the portions 4 of each group 3 can freely move relative to one another.

In the embodiment illustrated in the attached figures, the same moving means 18 cause, in each group 3 of portions 4 and downstream of the inspection station S3, a second relative movement between the portions 4 which is equal to and opposite to the first relative movement and shows the group 3 of portions 4 in the standard configuration (in which the portions 4 are axially aligned in end to end contact with one another as illustrated in Figure 6a and in Figure 7a) ; in other words, the same moving means 18 cause, in each group 3 of portions 4, the first relative movement upstream of the inspection station S3 so as to " explode" the group 3 of portions 4 and then cause, in the group 3 of portions 4, the second relative movement downstream of the inspection station S3 so as to "reconstitute" the group 3 of portions 4.

According to an alternative embodiment not illustrated, additional moving means could be provided (different and separate from the moving means 18) which cause, in each group 3 of portions 4 and downstream of the inspection station S3 the second relative movement between the portions 4 which is equal to and opposite to the first relative movement and shows the group 3 of portions 4 in the standard configuration.

In the embodiment illustrated in the attached figures (and clearly visible in Figures 7a and 7b), each seat 16 comprises a central fixed part 19 which is rigidly connected to the drum 14 so as to avoid any relative movement with respect to the drum 14 itself and two lateral movable parts 20, which are arranged at the opposite ends of the central fixed part 19 and are mounted movable on the drum 14 so as to move forward and backward relative to the drum 14 itself, in a separation direction D, which is perpendicular to the path P and under the thrust of the moving means 18. In other words, in each seat 16 the central fixed part 19 always remains in the same position relative to the drum 14, while the two lateral mobile parts 20 move cyclically forward and backward relative to the drum 14 (and therefore relative to the central fixed part 19) so as to be leaning against the central fixed part 19 in the input station SI and output station S2 (as illustrated in Figure 7a) and be offset from the central fixed part 19 in the inspection station S3 (as illustrated in Figure 7b) .

In the embodiment illustrated in the attached figures, in each seat 16 the central fixed part 19 houses three portions 4 and the two lateral movable parts 20 each housing an individual portion 4; in a different embodiment not illustrated, in each seat 16 the central fixed part 19 houses an individual portion 4 and the two lateral movable parts 20 each housing two portions 4, or in each seat 16 the central fixed part 19 houses two portions 4, a lateral movable part 20 houses two portions 4 and the other lateral movable part 20 houses an individual portion 4. According to alternative embodiments not illustrated, each seat 16 comprises only a lateral movable part 20 (which can house, for example, one two or three portions 4) or each seat 16 comprises three or four lateral movable parts 20 (which can each house one or two portions 4) . The number and arrangement of the movable parts 20 is established on the basis of the number and position of the portions 4 of each group 3 of which the length (i.e. the axial dimension) is to be measured with precision; in this regard it is important to specify that each group 3 of portions 4 could comprise any number of portions 4 generally ranging between two and seven.

Figure 7a illustrates a seat 16 of the drum 14 in the standard configuration (corresponding to the group 3 of portions 4 illustrated in Figure 6a) , whereas Figure 7b illustrates a seat 16 of the drum 14 in the exploded configuration (corresponding to the group 3 of portions 4 illustrated in Figure 6b) . As illustrated in Figures 7a and 7b, the moving means 18 comprise a pair of fixed cams 21 arranged in a fixed position (i.e. motionless movement) around the rotation axis 15 and, for each seat 16, a pair of cam-followers 22, which are supported by the drum 14, engage the corresponding cams 21, and are mechanically connected with the corresponding lateral movable parts 20 of the seat 16. According to other embodiments not illustrated, the moving means 18 comprise, for each seat 16, a corresponding electric actuator (a rotary electric motor or a linear electric motor) or a corresponding pneumatic actuator.

In the embodiment illustrated in the accompanying figures, each seat 16 of the drum 14 comprises a fixed part 19 and (at least) a movable part 20 so that in each seat 16 the portions 4 of the corresponding group 3 do not perform any relative movement with respect to the seat 16, but if the seat 16 itself is to make a relative movement with respect to the drum 14 which determines the separation of the portions 4 (i.e. the moving means 18 act on the seats 16 so as to separate the groups 3 of portions 4, then act indirectly on the portions 4 as they do not come into contact with the portions 4); in this embodiment, each seat 16 has exactly the same dimensions as the group 3 of portions 4, as no movement of the group 3 of portions 4 is provided in respect to the seat 16. According to other embodiments not illustrated, each seat 16 of the drum 14 comprises only a fixed part 19 and the moving means 18 act directly on the portions 4 to move the portions 4 and thus determine a separation of the groups 3 inside the corresponding seats 16; in this embodiment, each seat 16 has a dimension larger than the corresponding dimension of the group 3 of portions 4 for allowing an expansion of the group 3 of portions 4 inside the seat 16. By way of example, the moving means 18 could comprise pneumatic pushers (i.e. based on suction or blow) and/or mechanical pushers which cause the expansion/reconstitution movement in each group 3 of portions 4 inside a corresponding seat 16.

In the embodiment illustrated in Figures 1-7 (and well summarized in Figures 6a and 6b) , the separation direction D (i.e. the relative movement between the portions 4 caused by the moving means 18) is axially orientated relative to the group 3 of portions 4; consequently, in the inspection station S3 and in each group 3 of portions 4 the two lateral portions 4 are axially spaced apart from the three central portions 4. In the alternative embodiment illustrated in Figures 7a and 7b, the separation direction D (i.e. the relative movement between the portions 4 caused by the moving means 18) is orientated radially relative to the group 3 of portions 4; consequently, in the inspection station S3 and in each group 3 of portions 4 the two lateral portions 4 are radially spaced apart (i.e. misaligned, staggered) from the three central portions 4. According to what is schematically illustrated in Figure 2, the inspection unit 12 comprises a processing unit 23 which is connected to the optical device 17 and is adapted to determine, in each group 3 of portions 4, the actual length of each of the two lateral portions 4 (which are singularly detected as they are singularly separated from the other portions 4) and the actual length of the three central portions 4 (which are detected together in mutual contact) thus processing, in a known manner, the corresponding image detected by the optical device 17 in the inspection station S3. Furthermore, the inspection unit 12 comprises a rejection unit 24 which is connected to the processing unit 23 and is adapted to reject a group 3 of portions 4 in which at least one portion 4 has a non-compliant actual length (i.e. an actual length which deviates from a nominal length of a quantity greater, in absolute value, than a predetermined acceptability threshold) . For example, the rejection unit 24 could comprise a pneumatic expulsion device (i.e. using a compressed air blow) which extracts a group 3 of portions 4 from the corresponding seat 16 and directs the group 3 of portions 4 into a waste collection container.

According to a possible embodiment, the measurement of the actual length of the portions 4 of the groups 3 of portions could also be used to adjust, following feedback, the cut of the portions 4 in the feeding units 8; in particular, a moving average of the actual length of the portions 4 forming the groups

3 of the portions is preferably used and the cut of the portions

4 in the feeding units 8 is controlled, following feedback, by using the moving average of the actual length of the portions 4 as a variable feedback. Likewise, the measurement of the actual length of the portions 4 forming the groups 3 of portions could also be used to adjust, following feedback, the transversal cut of the filter rod to separate the combined filters 2 from the filter rod; in particular, a moving average of the actual length of the portions 4 forming the groups 3 of the portions is preferably used and the transversal cut of the filter rod to separate the combined filters 2 from the filter rod is controlled, following feedback, by using the moving average of the actual length of the portions 4 as a variable feedback .

The embodiments described herein can be combined without departing from the scope of protection of the present invention.

The inspection unit 12 described above has several advantages.

Firstly, the inspection unit 12 described above allows to measure with extreme precision the length (axial dimension) of the individual portions 4 forming each group 3 of portions 4, as when the optical device 17 captures the image of the group 3 of portions 4 at least a part of the portions 4 is physically separated from the other portions 4 thus clearly pointing out the respective ends (which can then be easily and accurately identified in the image captured by the optical device 17) .

Furthermore, the inspection unit 12 described above in no way damages the portions 4 (which are moved axially or radially in a very delicate manner thus preserving their integrity) , nor the wrapping sheet (which is not provided at the inspection unit 12 since it is fed only downstream of the inspection unit 12) .

Finally, the inspection unit 12 described above is simple and inexpensive to implement, as it requires small modifications to a suction drum for feeding the groups 3 of portions 4.

The inspection unit 12 described above operates on groups 3 of filter portions 4; the same type for the inspection unit 12 could operate without substantial changes on groups 3 of portions of smoking articles other than filters (for example, the smoking articles could be new generation, combustion-free cigarettes) .

Claims

1. A unit (12) for the inspection of a group (3) of portions (4) of tobacco industry articles; the inspection unit (12) comprises :

a transport device (13) comprising a seat (16), which is adapted to house the group (3) of portions (4) and feed along a path (P) , which extends between an input station (SI) and an output station (S2); and

an optical device (17), which is arranged along the path (P) in the area of an inspection station (S3) so as to capture at least one image of the group (3) of portions (4);

wherein, in the input station (SI) and in the output station (S2), the group (3) of portions (4) is in a first configuration, in which the portions (4) are axially aligned in end to end contact with one another; and

wherein the group (3) of portions (4) has no elements that join the portions (4) to one another and, therefore, the portions (4) can freely move relative to one another;

the inspection unit (12) is characterized in that it comprises first moving means (18), which are coupled to the transport device (13) so as to cause, in the group (3) of portions (4), a first relative movement between the portions (4) upstream of the inspection station (S3) , so that, at the inspection station (S3) the group (3) of portions (4) is in a second configuration, in which at least one portion (4) is misaligned with and/or spaced apart from the other portions (4) .

2. The inspection unit (12) according to claim 1, wherein the first moving means (18) cause, in the group (3) of portions (4) and downstream of the inspection station (S3), a second relative movement between the portions (4), which is equal to and opposite the first relative movement and takes the group (3) of portions (4) back to the first configuration.

3. The inspection unit (12) according to claim 1 and comprising second moving means (18) which are different from the first moving means (18) and cause, in the group (3) of portions (4) and downstream of the inspection station (S3), a second relative movement between the portions (4) which is equal to and opposite to the first relative movement and takes the group (3) of portions (4) back to the first configuration.

4. The inspection unit (12) according to one of the claims from 1 to 3, wherein the seat (16) comprises at least one movable part (20), which is mounted movable on the transport device (13) so as to move back and forth, relative to the transport device (13), in a separation direction (D) , which is perpendicular to the path (P) due to the thrust of the first moving means (18) .

5. The inspection unit (12) according to claim 4, wherein the first moving means (18) comprises a fixed cam (21) and a cam follower (22) which is supported by the transport device (13), engages the cam (21), and is mechanically connected to the movable part (20) of the seat (16) .

6. The inspection unit (12) according to claim 4 or 5, wherein the seat (16) comprises a fixed part (19) which is mounted rigid on the transport device (13) and is arranged beside the movable part (20) of the seat (16) .

7. The inspection unit (12) according to claim 6, wherein the seat (16) comprises a pair of movable parts (20), which are arranged on opposite sides of the fixed part (19) .

8. The inspection unit (12) according to any one of the claims from 1 to 7, wherein the first relative movement between the portions (4), which is caused by the first moving means (18), is orientated axially relative to the group (3) of portions (4) .

9. The inspection unit (12) according to one of the claims from 1 to 7, wherein the first relative movement between the portions (4), which is caused by the first moving means (18), is orientated radially relative to the group (3) of portions (4) .

10. The inspection unit (12) according to one of the claims from 1 to 9 and comprising a processing unit (23), which is connected to the optical device (17) and is adapted to determine the length of at least one portion (4) by processing the image detected by the optical device (17) .

11. The inspection unit (12) according to claim 10 and comprising a rejection unit (24) which is connected to the processing unit (23) and is adapted to reject the group (3) of portions (4) if there is at least one portion (4) with a non-compliant length.

12. A manufacturing machine (1) for the production of tobacco industry articles and comprising:

a combining unit (5) which creates the groups (3) of portions (4) by arranging at least two different portions (4) axially aligned in end to end contact with one another; and

a wrapping unit (6), which receives a succession of groups (3) of portions (4) from the combining unit (5), wraps a wrapping material strip around the succession of groups (3) of portions (4) so as to form a continuous rod, and finally separates components (2) from the continuous rod by means of a cyclic transverse cut of the rod;

the manufacturing machine (1) is characterized in that it comprises an inspection unit (12) according to any one of the claims from 1 to 11, which is arranged between the combining unit (5) and the wrapping unit (10) .

13. The manufacturing machine (1) according to claim 12 and comprising a transfer unit (7) which transfers the groups (3) of portions (4) from the transport device (13) of the inspection unit (12) to the wrapping unit (6) .

14. A method for the inspection of a group (3) of portions (4) of tobacco industry articles; the inspection method comprises the steps of :

feeding, along a path (P) that extends between an input station (SI) and an output station (S2), a seat (16), which is adapted to house the group (3) of portions (4) and is part of a transport device (13) ; and

capturing at least one image of the group (3) of portions (4) by means of an optical device (17), which is arranged along the path (P) at an inspection station (S3) ;

wherein, in the input station (SI) and in the output station {S2 ) , the group (3) of portions (4) is in a first configuration, in which the portions (4) are axially aligned in end to end contact with one another; and

the inspection method is characterized in that it comprises the further step of causing, by means of moving means (18) coupled to the transport device (13), in the group (3) of portions (4), a relative movement between the portions (4) upstream of the inspection station (S3) , so that, at the inspection station (S3) the group (3) of portions (4) is in a second configuration, in which at least one portion (4) is misaligned with and/or spaced apart from the other portions (4) .