EP2978324B1

EP2978324B1 - Conveyor for transferring rod-shaped smokers' articles

Info

Publication number: EP2978324B1
Application number: EP14716961.9A
Authority: EP
Inventors: Fulvio Pastore; Lorenzo SELMI; Nicola VISCANTI; Massimo Sartoni
Original assignee: GD SpA
Current assignee: GD SpA
Priority date: 2013-03-27
Filing date: 2014-03-26
Publication date: 2018-10-31
Anticipated expiration: 2034-03-26
Also published as: WO2014155317A1; ITBO20130131A1; EP2978324A1

Description

Technical field

This invention relates to a conveyor for transferring rod-shaped smokers' articles.
More specifically, the invention has for an object a conveyor for transferring cigarettes or filter plugs, to which reference is hereinafter made without thereby limiting the scope of the invention.
This description refers, without limiting the scope of the invention, to a drum conveyor rotatable about a respective axis and peripherally provided with a plurality of grooves, or flutes, angularly equispaced from each other, running parallel to the drum axis and capable of receiving the smokers' articles moving axially into them and applying suction to the smokers' articles in such a way as to gradually slow them down to a stop and hold them within.

Background art

Drums of the above mentioned type are commonly used, for example, in machines for attaching filter tips to cigarettes and in machines for making filter plugs, see for example EP 0 682 881 A2 .
Each flute on these drums is provided with a plurality of radial holes, each of which has one end facing outside the drum and the other end, positioned inside the drum and, during the period in which a smokers' article must be held in contact with the flute itself, in communication with a chamber which is in turn connected to a source of suction comprising a suction pump.
During operation of a machine equipped with a drum of this kind, it is necessary, in many cases frequently, to adjust the negative pressure which is transmitted to the radial holes communicating with the flutes. In effect, the optimum pressure value varies with variation, for example, of the type of smokers' articles being handled or even with variation of the operating speed of the machine. The negative pressure, for example, must be greater when the drum rotates at high speed, so as to better oppose the centrifugal force acting on the cigarette sticks or filter plugs, and must be less when the machine is starting up or is running at a low speed for any reason.
Also, since all the numerous conveyor drums in the machine, and not only the one of the type mentioned above, are usually connected to the same source of suction, if some of the smokers' articles fall out of their respective flutes for any reason, the suction holes in those flutes suddenly come into communication with the outside atmosphere causing the negative pressure to drop in all the holes in the flutes which are holding smokers' articles at that moment, with the result that the negative pressure applied through the holes may become insufficient to hold the other smokers' articles.
Adjusting the negative pressure in the drums concerned is usually accomplished by means of valve elements comprising a movable shutter, in particular of the rotary type which can be moved relative to the aperture for the air sucked in, thereby obstructing the aperture to variable extents. These valve elements are relatively unreliable because their operation is strongly affected by the presence, in the air flowing through them, of tobacco dust or substances such as sand mixed with the tobacco (when cigarettes are being handled) or cellulose dust mixed with carbon dust (when filter plugs containing active carbon are being handled). The inevitable presence of these substances causes wear and build-up of dirt, which in turn may lead to clogging up, making the valve elements unfit for use to adjust the negative pressure as described above, which in some cases must be carried out very rapidly.

Disclosure of the invention

This invention has for aim to provide a conveyor for transferring rod-shaped smokers' articles which overcomes the disadvantages described above with reference to the prior art and which is at once relatively simple and inexpensive to construct.
According to the invention, a conveyor for transferring rod-shaped smokers' articles as claimed in the appended claims is provided.

Brief description of the drawings

The invention is described below with reference to the accompanying drawings, which illustrate a non-limiting embodiment of it and in which:

Figure 1 is a schematic perspective view of two machines for handling smokers' articles;
Figures 2-4 are three schematic plan views of a detail of one of the machines of Figure 1, in three different operating conditions;
Figures 5 and 6 show two cross section views of details of the machine of Figures 2-4; and
Figures 7 and 8 show two further cross section views of details of the machine of Figures 2-4.

Detailed description of preferred embodiments of the invention

With reference to Figure 1, the numeral 1 denotes in its entirety a plant for handling rod-shaped smokers' articles 2, in particular filter plugs or cigarettes.
In the description which follows, reference is made by way of non-limiting example to the production of smokers' articles consisting of filter plugs 2. The plant comprises a making machine 3 along which a (at least one) continuous rod 4 of filter material wrapped in a paper material is made in essentially known manner and is fed axially through a cutting station 5 where a cutting device 6 cuts the rod 4 into a sequence of filter plugs 2. The filter plugs 2 are delivered axially one after the other to a receiving roller or drum 7 constituting the infeed section of a handling machine 8 comprising, for example, an assembling machine designed to make filter plugs, each consisting of two or more plugs of filter material of different types. The drum 7 is rotatable continuously about a horizontal axis A parallel to the feed direction of the continuous rod 4 and is able to receive respective filter plugs 2 fed axially into elongate flutes 9 formed on its cylindrical peripheral surface at equal angular intervals and running parallel to the axis A. Each flute 9 receives and holds within it by suction a filter plug 2. The drum 7 transfers the filter plugs 2 in sequence to angularly equispaced suction flutes 10 of a further drum 11, counterrotating relative to the drum 7 and in the same way, the drum 11 transfers the filter plugs 2 in sequence to angularly equispaced, peripheral suction flutes 12 formed on a drum 13 which counterrotates relative to the drum 11. On the drums 11 and 13, as well as on further similar drums not illustrated the filter plugs 2 are subjected to operations by which a finished smokers' article is formed.
With reference to Figures 5-8, the receiving drum 7 is defined, at its cylindrical surface, by a substantially cylindrical hollow mantle 14.
Each of the flutes 9 formed on the mantle 14 has an inlet portion 15 located at the portion of the drum 7 which axially faces the making machine 3, and an end portion 16 extending between the inlet portion 15 and the axial end of the drum 7 furthest from the selfsame making machine 3. The inlet portion 15 of each flute 9 has a length which is substantially equal to the length of a filter plug 2, a transverse dimension which decreases, starting from the end of it giving access to a filter plug 2. from a value exceeding the diameter of a filter plug 2 to a value substantially equal to that diameter, and a depth preferably exceeding the length of the radius of the filter plugs 2. The inlet portion 15 is, in essentially known manner, defined along the leading side of it, relative to the direction of rotation of the drum 7, by an edge which is inclined with respect to a longitudinal axis of extension of the respective flute 9. The end portion 16 of each flute 9 has a length similar to that of the inlet portion 15 and a constant transverse dimension substantially equal to the diameter of a filter plug 2 or just greater than the diameter of a filter plug 2. The end portion 16 of each flute 9 is delimited, at an end zone of it opposite that which communicates with the inlet portion 15, by a stop member 17 integral with the cylindrical peripheral surface of the mantle 14 of the drum 7.
On the inlet portion 15 and on the end portion 16 of each flute 9 there are respective rows 18, 19 of holes 20, 21 formed radially relative to the mantle 14, there being, in the example illustrated in Figures 7 and 8, eight holes per row. The holes 20 and 21 have respective ends giving onto the surface of the respective flute 9 intended to receive a filter plug 2. Housed in a fixed position inside the mantle 14 of the receiving drum 7 there are two Venturi- effect ejectors 22 and 23. In an essentially known manner, a Venturi-effect ejector is used to produce a negative pressure using the kinetic energy of an air jet made to flow into the Venturi tube present in the ejector itself upstream of the narrow section. In the convergent part of the Venturi tube the air moved by the air jet which causes a negative pressure increases its kinetic energy which is reconverted into pressure energy in the divergent part.
The holes 20 and 21 forming part of the rows 18 and 19, respectively, present in the inlet portion 15 and in the end portion 16 of each flute 9 are connected to respective chambers 24 and 25 formed on the peripheral surface of a substantially cylindrical shell 26 running alongside the inside surface of the mantle 14 of the drum 7 (Figures 5-8). Each of the chambers 24 and 25 communicates with one of the reduced cross-section zones 27 and 28 of the internal duct 22', 23' of a respective Venturi- effect ejector 22, 23. As a result, when an air jet from a source of compressed air 29 is made to flow into one end of each of the Venturi- effect ejectors 22 and 23, suction is produced in the chambers 24 and 25 connected respectively thereto and whose intensity can easily be adjusted using respective valve elements 30, 31 interposed between the source of compressed air 29 and the Venturi- effect ejectors 22 and 23 to modify the pressure of the air blown into the Venturi- effect ejectors 22 and 23 themselves. As the mantle 14 of the drum 7 rotates about the axis A, this negative pressure is transmitted, respectively, from the chambers 24 and 25 to the rows 18 and 19 of holes 20 and 21 of the flutes 9 when the holes 20 and 21 are located with the ends of them inside the drum 7 facing the chambers 24 and 25, that is to say, with reference to Figure 1, along the arc B travelled by the flutes 9 between the zone where they are axially aligned with the continuous rod 4 of filter material from the making machine 3 and the zone of substantial tangency between the drum 7 and the drum 11.
As shown in Figures 2 to 4, each filter plug 2 from the making machine 3 axially enters a flute 9 of the drum 7, and the front end of that filter plug 2, during its entry into the flute 9 itself, remains in a position facing an inclined leading edge (with reference to the direction of rotation of the drum 7) of the inlet portion 15 of the flute 9, and is suddenly slowed down by the row 18 of suction holes 20, and completes access to the inlet portion 15 of the flute 9 before being reached by the trailing edge of the flute 9 itself, against which it abuts. The axial motion of the filter plug 2 then continues onto the end portion 16 of the flute 9, which progressively slows it down to a stop thanks to the suction applied through its row 19 of holes 21. The filter plug 2 stops in exactly the right position because the filter plug 2 comes into abutment very gently against the stop member 17 associated with the end of the flute 9.
The intensity of the suction applied through the holes 20 and 21 of the inlet portion 15 and of the end portion 16 of the flutes 9 travelling the arc B may be selected by acting on the valve elements 30, 31 in such a way that the suction applied at the inlet portion 15 is greater than that at the end portion 16 (filter plug 9 slowed down rapidly and stopped slowly) but it is possible to select the opposite option (filter plugs 9 slowed down more progressively and stopped relatively rapidly). The choice between these options depends on parameters such as, for example, the type of smokers' articles to be handled by the drum 7 (filter plugs, cigarettes), for each of which one type of handling may be preferable to another taking into account the different fragility of the articles themselves.
From the foregoing, it is evident that the drum 7 described is capable of totally eliminating the disadvantages described with reference to the prior art.
In effect, the air used in combination with the Venturi- effect ejectors 22 and 23 is totally free of contamination by tobacco, dust or other substances which might negatively affect the possibility of adjusting the negative pressure applied through holes 20 and 21 of the flutes 9.
In a variant embodiment, not illustrated, of this invention, the Venturi- effect ejectors 22 and 23 might be substituted for a single Venturi-effect ejector, whose narrow cross-section zone is connectable to both rows 18 and 19 of holes 20 and 21. In effect, in this case, too, the disadvantages typical of the prior art would be avoided, although it would not be possible to adjust the negative pressure applicable through the two rows 18 and 19 of holes 20 and 21 in the flutes 9 independently of each other.
It should be noted that the conveyor of the invention, comprising the aforementioned receiving drum 7, might also be a belt conveyor provided with suction flutes on its transporting surface, or it might rotate about an axis which is not horizontal.
Lastly, it should be noted that the making machine 3 described by way of an example makes one continuous rod 4 of filter material wrapped in a strip of paper material, divides the rod into plugs 2 and feeds the plugs 2 into respective flutes 9 on a drum 7. The solution of the invention can, however, be used equally well in combination with a making machine 3 which can make more than one continuous rod 4 of filter material alongside each other, where the plugs 2 obtained from the two rods 4 are fed to respective flutes 9 of respective drums 7 which are mutually juxtaposed and preferably counterrotating.

Claims

A conveyor for transferring rod-shaped smokers' articles, provided with a plurality of elongate flutes (9) designed to receive respective smokers' articles (2) fed into the flutes (9) by axial motion and to hold them by suction applied, in each flute (9), through a plurality of suction holes (20, 21) having respective first ends giving onto a surface of the flute (9); said conveyor comprising a rotary drum (7) which revolves about an axis (A) and whose substantially cylindrical peripheral surface is furnished with a plurality of elongate flutes (9), spaced at equal angular intervals from each other and running parallel to the selfsame axis (A); each flute (9) having an inlet portion (15) and an end portion (16) and each inlet portion (15) having a transverse dimension, starting from the end of it giving access to the smokers' article (2) which decreases from a value exceeding the diameter of a smokers' article (2) to a value substantially equal to that diameter and being defined along the leading side of it, relative to the direction of rotation of the drum (7), by an edge which is inclined with respect to a longitudinal axis of extension of the selfsame flute (9); characterized in that it comprises at least one Venturi-effect ejector (22, 23) associated with the conveyor (7), and a source of compressed air (29) leading to one end of the internal duct (22', 23') of the at least one Venturi-effect ejector (22, 23); the second ends of the holes (20, 21) associated with the flutes (9) being connectable to a reduced cross-section zone (27, 28) of the selfsame internal duct (22', 23').
The conveyor according to claim 1, characterized in that it comprises two Venturi-effect ejectors (22, 23) with one end of their respective internal ducts (22', 23') leading to a source of compressed air (29); the second ends of the holes (20, 21) associated, respectively, with the inlet portion (15) and the end portion (16) of each flute (9) being connectable to a reduced cross-section zone (27, 28) of the internal duct (22', 23') of a respective Venturi-effect ejector (22, 23).
The conveyor according to claim 2, characterized in that it comprises valve means (30, 31) interposed between the source of compressed air (29) and the respective internal ducts (22', 23') of the two Venturi-effect ejectors (22, 23).
The conveyor according to any one of the preceding claims, characterized in that the suction applied through the holes (20) of the inlet portion (15) of each flute (9) is greater than the suction applied through the holes (21) of the end portion (16).
The conveyor according to any one of the preceding claims, characterized in that the suction applied through the holes (20) of the inlet portion (15) of each flute (9) is less than the suction applied through the holes (21) of the end portion (16).
The conveyor according to any one of the preceding claims, characterized in that an end portion (16) of each flute (9) is delimited, at an end zone of it opposite that which communicates with the inlet portion (15), by a stop member (17).
The conveyor according to claim 6, characterized in that the stop member (17) is integral with a cylindrical peripheral surface of a mantle (14) of the drum (7).
The conveyor according to claim 7, characterized in that the stop member (17) located in the end portion (16) of each flute (9) is designed to ensure that the smokers' article (2) stops in the correct position after the smokers' article (2) is fed in very gently in abutment against the selfsame stop member (17).