EP4669606A1

EP4669606A1 - METHOD FOR FEEDING TUBE-SHAPED PRODUCTS AND ASSOCIATED FEEDING UNIT

Info

Publication number: EP4669606A1
Application number: EP24713538.7A
Authority: EP
Inventors: Fabrizio Tale'; Maria Elena FANTONI
Original assignee: IMA Industria Macchine Automatiche SpA
Current assignee: IMA Industria Macchine Automatiche SpA
Priority date: 2023-02-20
Filing date: 2024-02-20
Publication date: 2025-12-31
Also published as: MX2025009806A; WO2024176273A1; DOP2025000203A; IT202300002790A1

Abstract

The feeding method comprises the steps of feeding tubular products (P) to a first conveyor wheel (11) which comprises, regularly distributed along its peripheral edge, a plurality of first seatings (110), making the first conveyor wheel (11) rotate so as to convey the tubular products (P) along a first path (Pl) from an inlet station (SI) to a transfer station (S2), in which the tubular products (P) are transferred to a second conveyor wheel (12) which comprises, regularly distributed along its peripheral edge, a plurality of second seatings (120), and checking the first seatings (110) of the first conveyor wheel (11) upstream of the transfer station (S2) to verify that they are correctly occupied.

Description

TUBULAR PRODUCT FEEDING PROCESS AND ASSOCIATED FEEDING UNIT

FIELD OF THE INVENTION The present invention concerns a method for feeding tubular products and a corresponding feed unit. In particular, the feeding method and unit provide that the tubular products are fed to a first conveyor wheel and then transferred to a second conveyor wheel.

BACKGROUND OF THE INVENTION Feed units are known which comprise a first conveyor wheel and a second conveyor wheel, which can simply convey tubular products or possibly perform operations on them, such as applying a film of wrapping material to package the tubular products, for example. These operations are carried out with the help of special tools located in the proximity of the wheels so that they can act on the conveyed products.

The wheels of the known units contain a plurality of seatings, regularly distributed along their periphery, configured to each accommodate a single tubular product. The two wheels are driven with synchronized speeds so that, in correspondence with a transfer station, a seating of the first wheel arrives at the same time as a seating of the second wheel so as to be able to transfer the tubular product from the first wheel to the second wheel, and subsequently the seatings of the first wheel arrive at the same time as a seating of the second wheel.

Obviously, the speeds of the two wheels can be the same or different. This depends on several characteristics of the two wheels, in particular the diameter and the number of seatings of each wheel.

A problem with known units and methods occurs when a seating of the first wheel is not filled, due to a problem in the upstream feed of the tubular products, or it contains a tubular product to be discarded, because not compliant, for example damaged or of irregular sizes, and therefore not to be transferred to the second wheel.

In known units, a seating in the first wheel that is empty or contains a product to be discarded, results in an empty seating in the second wheel, which requires a corrective action downstream which will negatively impact the productivity of the apparatus as a whole, for example interrupting the continuous exit of finished products.

In the field of packaging plants, for example for manufacturing plastic bottles starting from preforms, the prior art document US 2019/056712 describes a solution in which it is provided to operatively couple two operating stations, one belonging to a first machine and the other to a second machine. In this solution, the bottles processed by a certain station of the first machine are always formed by a certain operating station of the second machine, so that in the presence of defective products it is always possible to trace back to the operating stations of the two machines that were involved in the process. This solution provides to drive the two machines independently so that the two operating stations selected for production can be placed alongside each other on each occasion. Although this solution is versatile, it is certainly complex, because the machines described in US 2019/056712 are not limited to the transfer of products but also carry out all the operations required to manufacture them, including heating and injection molding units.

There is therefore the need to perfect a method and a unit for feeding tubular products that can overcome at least one of the disadvantages of the state of the art.

To do this, it is necessary to solve the technical problem of ensuring that all the seatings of the second wheel are filled with a respective tubular product, regardless of whether or not voids or non-compliant products are detected in the first wheel.

In particular, one purpose of the present invention is to perfect a method for feeding tubular products which allows to manage any missing or non-compliant products exclusively at the level of the first conveyor wheel. Another purpose of the present invention is to provide a feed unit that allows to implement the method as above.

The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages. SUMMARY OF THE INVENTION

The present invention is set forth and characterized in the independent claims. The dependent claims describe other characteristics of the present invention or variants to the main inventive idea. In accordance with the above purposes and to resolve the technical problem disclosed above in a new and original way, also achieving considerable advantages compared to the state of the prior art, a method according to the present invention for feeding tubular products comprises the following steps: feeding, in correspondence with an inlet station, the tubular products to a first conveyor wheel which comprises, regularly distributed along a first peripheral edge thereof, a plurality of first seatings, each configured to accommodate a respective tubular product; rotating the first conveyor wheel at a first speed to convey the tubular products accommodated into the respective first seatings along a first path from the inlet station to a transfer station; transferring the tubular products from the first conveyor wheel to a second conveyor wheel in correspondence with the transfer station, the second conveyor wheel comprising, regularly distributed along a second peripheral edge thereof, a plurality of second seatings, each of the second seatings being configured to accommodate a respective tubular product, the second conveyor wheel being driven in rotation at a constant second speed so that each second seating reaches the transfer station at the same time as a first seating of the plurality of first seatings of the first conveyor wheel; checking, before each first seating reaches the transfer station, to verify whether the first seatings are correctly occupied by the tubular products.

In accordance with one aspect of the present invention, the method provides that, in case at least one of the first seatings has been verified to be incorrectly occupied, the rotation of the first conveyor wheel is accelerated when the last preceding first seating, which has been verified to be correctly occupied, leaves the transfer station, so that the at least one of the first seatings, that has been verified to be incorrectly occupied, reaches the transfer station at a time when none of the second seatings of the second conveyor wheel is at the transfer station.

Doing so achieves at least the advantage of preventing an incorrectly occupied seating in the second conveyor wheel, without having to modify its speed of rotation. In this way, the operating speed of a plant downstream of the second conveyor wheel is not affected by an incorrect loading (empty seating or product to be discarder) in the first conveyor wheel of the feed unit. In the context of this application, by incorrectly occupied seating we mean an empty seating, without a tubular product, or a seating in which the tubular product is to be discarded, because it is damaged or its sizes do not comply to those expected, or suchlike. Advantageously, the first speed of rotation of the first conveyor wheel is resynchronized with the constant second speed when the first successive seating, that has been verified to be correctly occupied, reaches the transfer station, so that again each first seating reaches the transfer station at the same time as each second seating. In this way, having “skipped” the incorrectly occupied seating, the method provides that the feed of the tubular products is once again performed normally.

According to some embodiments, the checking step of the first seatings is performed by means of a detection device placed between the inlet station and the transfer station. Advantageously, the checking device is of the visual check type.

In accordance with some embodiments, when at least one of the first seatings has been verified to be incorrectly occupied, the first conveyor wheel is driven to rotate at an accelerated speed of rotation which is higher than a first speed of rotation at which the first conveyor wheel normally rotates when the first seatings have been verified to be correctly occupied.

According to some embodiments, when the first conveyor wheel rotates at the accelerated speed of rotation, more than one tubular product is individually loaded into consecutive first seatings of the first conveyor wheel in correspondence with the inlet station.

According to some embodiments, the accelerated speed of rotation has a value that is correlated to the number of consecutive incorrectly occupied first seatings of the first conveyor wheel. In particular, the accelerated speed of rotation is equal to the first speed of rotation multiplied by a number obtained by adding one to the number of consecutive incorrectly occupied first seatings (Vacc = VI x (n+1), where Vacc is the speed during the acceleration, VI is the first speed and n is the number of consecutive incorrectly occupied first seatings. Favorably, the second conveyor wheel rotates at a constant speed even when the first conveyor wheel has been accelerated, in particular even if some incorrectly occupied seatings have been detected in the first conveyor wheel.

In accordance with some embodiments, the first seatings of the first conveyor wheel are distanced from each other by a smaller pitch than that of the second seatings of the second conveyor wheel.

In accordance with some embodiments, the tubular products have an elongated shape and are accommodated into the first and second seatings with their respective longitudinal axis parallel to rotation axes of the first and second conveyor wheels.

In accordance with another aspect of the present invention, a feed unit for feeding tubular products comprises a first conveyor wheel configured to convey the tubular products along a first path from an inlet station to a transfer station and provided with a plurality of first seatings regularly distributed along a first peripheral edge thereof, each of the first seatings being configured to accommodate a single tubular product, a second conveyor wheel provided with a plurality of second seatings regularly distributed along a second peripheral edge thereof and each configured to accommodate a single tubular product, the second conveyor wheel being configured to receive the tubular products from the first wheel in correspondence with the transfer station, a detection device placed between the inlet station and the transfer station and configured to verify whether each first seating is correctly occupied by a tubular product, and a control unit communicating with the first conveyor wheel, the second conveyor wheel and the detection device. The first conveyor wheel is configured to be driven independently of at least the second conveyor wheel, preferably of the rest of an apparatus in which the feed unit is installed.

According to one aspect, the control unit is programmed in such a manner that, in case the detection device verifies that at least one of the first seatings is incorrectly occupied, the rotation of the first conveyor wheel is accelerated when the last preceding first seating, which has been verified to be correctly occupied, leaves the transfer station, so that the at least one of the first seatings, that has been verified to be incorrectly occupied, reaches the transfer station at a time when none of the second seating of the second conveyor wheel is at the transfer station.

In this way, the first conveyor wheel can be commanded independently of the second conveyor wheel and, in particular, its speed of rotation can be accelerated without changing the speed of rotation of the second conveyor wheel.

The first and second conveyor wheels advantageously have respective rotation axes parallel to each other. The first and second conveyor wheels lie on a common plane.

According to some embodiments, the first seatings have a respective accommodating groove extending parallel to a first rotation axis of the first conveyor wheel. In this way, the seatings of the first wheel are configured to accommodate the tubular products oriented parallel to the rotation axis of the first conveyor wheel. A similar configuration is provided for the second seatings of the second conveyor wheel.

In accordance with some embodiments, in correspondence with the transfer station, the first peripheral edge and the second peripheral edge have a common tangent. This minimizes the time for transferring the tubular products from the first to the second conveyor wheel, to the benefit of a greater ease in implementing the method disclosed above.

DESCRIPTION OF THE DRAWINGS

These and other aspects, characteristics and advantages of the present invention will become apparent from the following description an embodiment, given as a non-restrictive example with reference to the attached drawings wherein:

- fig. 1 is a front view of a unit for feeding tubular products, according to the present invention; and

- figs. 2 to 5 are enlarged views of a detail of unit for feeding tubular products of fig. 1 , in a sequence of operating steps.

We must clarify that the phraseology and terminology used in the present description, as well as the figures in the attached drawings also in relation as to how described, have the sole function of better illustrating and explaining the present invention, their purpose being to provide a non-limiting example of the invention itself, since the scope of protection is defined by the claims.

To facilitate comprehension, the same reference numbers have been used, where possible, to identify identical common elements in the drawings. It is understood that elements and characteristics of one embodiment can be conveniently combined or incorporated into other embodiments without further clarifications. DESCRIPTION OF AN EMBODIMENT OF THE PRESENT INVENTION

With reference to fig. 1, a feed unit 10 for feeding tubular products P according to the present invention comprises a first conveyor wheel 11 rotatable around a first rotation axis Al, and a second conveyor wheel 12 rotatable around a second rotation axis A2. The first and second rotation axes Al, A2 are parallel to each other (fig. 1).

The tubular products P are made of plastic material and are intended to be subsequently wrapped in a sheet of any material whatsoever, for example paper, cardboard, plastic, foil, tobacco, fabrics or any other sheet material that allows the tubular products P to be wrapped.

The first conveyor wheel 11 is equipped with a plurality of first seatings 110 regularly distributed along a first peripheral edge thereof, the first seatings 110 being configured to each accommodate a corresponding tubular product P. In particular, the first seatings 110 consist of at least one accommodating groove oriented parallel to the first rotation axis Al and with a substantially semi-circular section, so that the tubular products P are oriented parallel to the first rotation axis Al when they are loaded into the first seatings 110. The semi-circular section has a diameter practically equal to the external diameter of the tubular products P, in order to accommodate them stably.

The second conveyor wheel 12 is also equipped with a corresponding plurality of second seatings 120, substantially consisting of a substantially radial abutment. The second seatings 120 are also oriented so that the tubular products P are parallel to the second rotation axis A2 when they are loaded into the second seatings 120. The feed unit 10 also comprises an inlet station SI, located in correspondence with the periphery of the first conveyor wheel 11 , where the tubular products P are fed in a known manner. For example, the tubular products P are fed in orderly succession from a hopper 20, but other solutions for feeding the tubular products P can be provided. The passage of the tubular products P from the first conveyor wheel 11 to the second conveyor wheel 12 occurs in correspondence with a transfer station S2, located downstream of the inlet station S 1 with respect to the sense of rotation of the first conveyor wheel 11. In the example shown in the drawings, the transfer station S2 is in a position substantially diametrically opposite to the inlet station SI .

It is therefore clear that the first conveyor wheel 11 moves the tubular products P along a first path Pl that extends between the inlet station SI and the transfer station S2. In addition to the transfer station S2, the second conveyor wheel 12 moves the tubular products P along a second path P2.

In correspondence with the transfer station S2, the first and second conveyor wheels 11, 12 have a common tangent in correspondence with their respective peripheral edge, which allows to facilitate and speed up the transfer of the tubular products P from one wheel to the other.

To keep the tubular products P in the first seatings 110 along the first path Pl, the feed unit 10 comprises a first peripheral abutment member 13 that is coplanar with the first conveyor wheel 11 and covers the first peripheral edge thereof along the first path Pl, that is, between the inlet station SI and the transfer station S2. Similarly, a second peripheral abutment member 14 is provided along the second path P2 so as to keep the tubular products P stably in the second seatings 120 while they are conveyed by the second conveyor wheel 12.

The first and second peripheral abutment members 13, 14 each have a shaped end 15, 16 located in correspondence with the transfer station S2. These shaped ends 15, 16 each have a respective inclined flat surface 17, 18 located one in front of the other and parallel to each other, so as to form a passage channel of the tubular products P from the first 11 to the second conveyor wheel 12 (fig. 1). These flat surfaces 17, 18, which are suitably distanced from each other by a distance substantially equal to the external diameter of the tubular products P, define the transfer station S2.

During normal operation of the feed unit 10, the first conveyor wheel 11 is driven in rotation, around the first rotation axis Al, at a first speed VI and the second conveyor wheel 12 is driven in rotation, around the second rotation axis A2, at a second speed V2. The first speed VI and the second speed V2 are synchronized with each other so that whenever one seating 110 of the first conveyor wheel 11 arrives at the transfer station S2, one seating 120 of the second conveyor wheel 12 also arrives at the same transfer station S2 to receive the tubular product P automatically transferred from the seating 110 of the first conveyor wheel. In this way, each seating 110 of the first conveyor wheel 11 releases its tubular product P in the transfer station S2 and this product is immediately received by a seating 120 of the second conveyor wheel 12, each of these second seatings 120 being occupied by a respective tubular product P (fig. 1).

In particular, in the example shown, the first conveyor wheel 11 comprises sixty first seatings 110 while the second conveyor wheel 12 comprises nine second seatings 112, and the two conveyor wheels have substantially the same diameters. The second speed V2 of rotation is therefore substantially equal to the first speed VI of rotation multiplied by a factor of 60/9 (V2 = 60/9 x VI). To explain the invention completely and clearly, the example shown in the drawings provides that the first conveyor wheel 11 has a series of correctly occupied seatings 111 and one empty seating 112. With respect to the latter, and with respect to the sense of feed of the tubular products P, it is possible to distinguish the last preceding correctly occupied seating 113 and the first successive correctly occupied seating 114.

The feed unit 10 also comprises a detection device 30, for example a video camera placed in front of, and flat with respect to, the first conveyor wheel 11 along the first path Pl in order to visually check that all the first seatings 110 are correctly occupied, that is, that they are occupied with a tubular product P that complies to its subsequent use. As an alternative to the video camera, other checking devices can be used, visual or not, which allow to check that the first seatings 110 in the first path Pl are correctly occupied.

The first conveyor wheel 11 is equipped with a motor 40 thereof and the second conveyor wheel 12 is also equipped with a respective motor 50 thereof, for their drive in rotation. The motor 40 of the first conveyor wheel 11 is independent at least of the second conveyor wheel 12, but also of other members located downstream of the apparatus in which the feed unit 10 is installed. In this way, it is possible to modulate the speed of the first conveyor wheel 11 during the operation of the apparatus. The motor 50 of the second conveyor wheel 12 can be linked to other members downstream in order to drive them. The motor 40 of the first conveyor wheel 11 is favorably of the electric type. In this way, it is easy to modulate its speed, even over short intervals of time.

The feed unit 10 comprises a control unit 60 connected to the detection device 30 and to the motors 40, 50 of the two conveyor wheels 11, 12 so as to control them and command their drive in a synchronized manner. The control unit 60 also provides a user interface to allow an operator to act on the operating parameters of the feed unit 10.

The operation of the feed unit 10 described heretofore, which corresponds to the method according to the present invention, comprises the following steps.

As already mentioned above, during the normal operation of the feed unit 10 the first conveyor wheel 11 rotates at a speed VI and the second conveyor wheel 12 rotates at a speed V2, synchronized with VI so that each first seating 110 “meets” a second seating 120 in correspondence with the transfer station S2.

In the example shown, the first conveyor wheel 11 comprises a plurality of correctly occupied seatings 111 and one empty seating 112. We must clarify that the empty seating 112 has already been detected by the detection device 30, which has sent a corresponding signal to the control unit 60 so that it can command the motor 4, as will be indicated below.

Fig. 1 shows the transfer, from the first conveyor wheel 11 to the second conveyor wheel 12, of the tubular product P that precedes the one loaded into the last preceding correctly occupied seating 113 with respect to the empty seating 112. We must clarify that, at this time, in correspondence with the transfer station S2, both the seating 110 of the first conveyor wheel 11 from which the tubular product P is transferred, and also the seating 120 of the second conveyor wheel 12 which receives it, are present. During its transfer, the tubular product P flows along the passage channel delimited by the flat surfaces 17, 18 of the ends 15, 16 of the peripheral abutment members 13, 14. Once this transfer is completed, the first conveyor wheel 11 continues to rotate at the same speed VI and the second conveyor wheel 12 continues to rotate at the same speed V2 as before (fig. 2), and the last preceding correctly occupied seating 113 reaches the transfer station S2 (fig. 3), at the same time as a seating 120 of the second conveyor wheel 12. The transfer of the corresponding tubular product P from the first 11 to the second conveyor wheel 12 is determined.

Following this transfer, because the presence of the empty seating 112 has been detected, the control unit 60 commands the motor 40 so as to drive the first conveyor wheel 11 at an accelerated rotation speed Vacc around the rotation axis Al, so that the empty seating 112 reaches the transfer station S2 before the successive seating 120 of the second conveyor wheel 12, as shown in fig. 4. In other words, the rotation of the first conveyor wheel 11 is accelerated so that the empty seating 112 does not “meet” a seating 120 of the second conveyor wheel 12 in the transfer station 120. The accelerated speed Vacc is determined so that it is the first correctly occupied seating 114 that arrives at the transfer station S2 together with the successive seating 120 of the second conveyor wheel 12 (fig. 5). In this way, when the latter arrives at the transfer station S2, a transfer of a tubular product P occurs in any case, so that the seating 120 of the second conveyor wheel 12 is not empty.

In this example, since it is necessary to make two seatings 110 pass in a same time interval, instead of one, the accelerated speed Vacc is substantially twice the first speed VI (Vacc = 2 x VI).

More generally, the accelerated speed Vacc is determined on the basis of the number of consecutively detected empty seatings 112. The acceleration has to be such as to make all the consecutive empty seatings 112 pass through the transfer station S2 before this is reached by the seating 120 of the second conveyor wheel 12, which always rotates at the same speed V2. It is evident that the time interval that passes between two passages of two consecutive seatings 120 of the second wheel 12 in the transfer station S2 is constant. If the objective is for none of these seatings 120 to be empty, the time elapsed between two consecutive transfers must also be constant, and equal to the time interval indicated above.

Therefore, the acceleration has to be such as to make n empty seatings 112 pass through the transfer station S2, and to make the first successive correctly occupied seating 114 arrive to allow the transfer of a tubular product P. Therefore, in a same time interval, it is necessary to make n + 1 seatings 110 pass. Since the seatings 110 are regularly distributed along the periphery of the first conveyor wheel 11, the accelerated speed can generally be determined with the formula Vacc = (n + 1) x VI . As soon as the first successive correctly occupied seating 114 has reached the transfer station S2, the rotation speed of the first conveyor wheel 11 is restored to its initial value V 1 , in view of a normal operation thereof. Any future accelerations, and the value of the accelerated speed Vacc, will depend on the detection of other empty seatings 112 by the detection device 30. It is clear that modifications and/or additions of parts may be made to the feed unit 10 and to the feeding method as described heretofore, without departing from the scope of the present invention, as defined by the claims.

It is also clear that, although the present invention has been described with reference to some specific examples, a person of skill in the art will be able to achieve other equivalent forms of method for feeding tubular products and corresponding feed unit, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby. In the following claims, the sole purpose of the references in brackets is to facilitate their reading and they must not be considered as restrictive factors with regard to the field of protection defined by the claims.

Claims

1. Method for feeding tubular products (P), said method comprising the following steps: feeding, in correspondence with an inlet station (SI), said tubular products (P) to a first conveyor wheel (11) which comprises, regularly distributed along a first peripheral edge thereof, a plurality of first seatings (110), each of said first seatings being configured to accommodate a respective tubular product (P); rotating said first conveyor wheel (11) at a first speed (VI) to convey said tubular products (P) accommodated into the respective first seatings along a first path (Pl) from said inlet station (SI) to a transfer station (S2); transferring said tubular products (P) from said first conveyor wheel (11) to a second conveyor wheel (12) in correspondence with said transfer station (S2), said second conveyor wheel (12) comprising, regularly distributed along a second peripheral edge thereof, a plurality of second seatings (120), each of said second seatings being configured to accommodate a respective tubular product (P), the second conveyor wheel being driven in rotation at a constant second speed (V2) so that each second seating (120) reaches said transfer station (S2) at the same time as a first seating (110) of said plurality of first seatings (110) of said first conveyor wheel (11); checking before each first seating (110) reaches said transfer station (S2) to verify whether said first seatings (110) are correctly occupied by the tubular products (P); characterized in that in case at least one of the first seatings (112) has been verified to be incorrectly occupied, the rotation of said first conveyor wheel (11) is accelerated when the last preceding first seating (113), which has been verified to be correctly occupied, leaves said transfer station (S2), so that the at least one of the first seatings (112), that has been verified to be incorrectly occupied, reaches said transfer station (S2) at a time when none of the second seatings (120) of said second conveyor wheel (12) is at said transfer station (S2).

2. Method as in claim 1, characterized in that the first speed (VI) of rotation of said first conveyor wheel (11) is resynchronized with the constant second speed

(V2) when the first successive seatings (112), that has been verified to be correctly occupied, reaches said transfer station (S2), so that again each first seating (110) reaches said transfer station (S2) at the same time as each second seating (120).

3. Method as in claim 1 or 2, characterized in that the checking step of said first seatings (110) is performed by means of a detection device (30) placed between said inlet station (SI) and said transfer station (S2).

4. Method as in any claim hereinbefore, characterized in that when the at least one of the first seatings (112) has been verified to be incorrectly occupied, said first conveyor wheel (11) is driven to rotate at an accelerated speed of rotation (Vacc) which is higher than a first speed of rotation (VI) at which said first conveyor wheel (11) normally rotates when the first seatings (112) have been verified to be correctly occupied.

5. Method as in claim 4, characterized in that when said first conveyor wheel

(11) rotates at said accelerated speed of rotation (Vacc), more than one tubular product (P) is individually loaded into consecutive first seatings (110) of said first conveyor wheel (11) in correspondence with the inlet station (SI).

6. Method as in claim 4 or 5, characterized in that said accelerated speed of rotation (Vacc) has a value that is correlated to the number of consecutive incorrectly occupied first seatings of said first conveyor wheel (11).

7. Method as in any claim 4 to 6, characterized in that the accelerated speed of rotation (Vacc) of said first conveyor wheel (1 1) is equal to said first speed of rotation (VI) multiplied by a number obtained by adding one to the number (n) of consecutive incorrectly occupied first seatings (Vacc = VI x (n+1)).

8. Method as in any claim hereinbefore, characterized in that said second conveyor wheel (12) rotates at a constant speed (V2) even when the first conveyor wheel (11) has been accelerated.

9. Method as in any claim hereinbefore, characterized in that the first seatings (110) of the first conveyor wheel (11) are distanced from each other by a smaller pitch than that of the second seatings (120) of the second conveyor wheel (12).

10. Method as in any claim hereinbefore, characterized in that said tubular products (P) have an elongated shape and are accommodated into the first and second seatings (110, 120) with their respective longitudinal axis parallel to rotation axes (Al, A2) of the first and second conveyor wheels (11, 12).

11. Feed unit (10) for feeding tubular products (P), said feed unit (10) comprising a first conveyor wheel (11) configured to convey said tubular products (P) along a first path (P 1 ) from an inlet station (S 1 ) to a transfer station (S2) and provided with a plurality of first seatings (110) regularly distributed along a first peripheral edge thereof, each of said first seatings (110) being configured to accommodate a single tubular product (P), a second conveyor wheel (12) provided with a plurality of second seatings (120) regularly distributed along a second peripheral edge thereof, each of said second seatings (120) being configured to accommodate a single tubular product (P), said second conveyor wheel (12) being further configured to receive said tubular products (P) from said first conveyor wheel (11) in correspondence with said transfer station (S2), a detection device (30) placed between said inlet station (SI) and said transfer station (S2) and configured to verify whether each first seating (110) is correctly occupied by a tubular product (P), and a control unit (60) communicating with said first conveyor wheel (11), said second conveyor wheel (12) and said detection device (30), characterized in that said control unit (60) is programmed in such a manner that, in case the detection device (30) verifies that at least one of the first seatings (112) is incorrectly occupied, the rotation of said first conveyor wheel (11) is accelerated when the last preceding first seating (113), which has been verified to be correctly occupied, leaves said transfer station (S2), so that the at least one of the first seatings (112), that has been verified to be incorrectly occupied, reaches said transfer station (S2) at a time when none of the second seating (120) of said second conveyor wheel (12) is at said transfer station (S2).

12. Feed unit (10) as in claim 11, characterized in that the distance between adjacent first seatings is smaller than the distance between adjacent second seatings.

13. Feed unit (10) as in claim 11 or 12, characterized in that in correspondence with said transfer station (S2), the first peripheral edge and the second peripheral edge have a common tangent.

14. Feed unit (10) as in any claim 11 - 13, characterized in that the first seatings (110) have a respective accommodating groove extending parallel to a first rotation axis (Al) of said first conveyor wheel (11).

15. Feed unit (10) as in any claim 11 - 14, characterized in that said first and second conveyor wheels (11, 12) lie on a common plane.