METHOD AND A MACHINE FOR MAKING CIGARETTES, WITH RECOVERY OF TOBACCO FROM DEFECTIVE CIGARETTES

Technical field

This invention relates to a method and to a machine for making cigarettes, with recovery of tobacco from defective cigarettes.

Background art

In the production of cigarettes, the total number of cigarettes made inevitably includes defective cigarettes among the cigarettes which meet accepted standards of quality. Cigarette making machines are equipped with numerous checking devices by which each cigarette is tested for conformity to specifications. In effect, it is necessary to check that every cigarette made contains the right quantity of tobacco, that there is enough tobacco at the end opposite the filter to make that end sufficiently compact to prevent the tobacco from falling out, that the paper wrapped around the tobacco is correctly glued and is not torn or stained, and so on.

The cigarettes found to be defective are rejected at specific expulsion stations and are collected, usually in specific containers, and then transferred to specific machines especially designed to recover the tobacco from them.

In these machines, the defective cigarettes are crushed or the paper is cut lengthways by a blade, and the different cigarette parts (filter, paper and tobacco) are separated. The filters and paper are scrapped, whereas the tobacco is recovered and then re-used in cigarette making machines. There are numerous examples of machines of the above mentioned type for recovering tobacco from defective cigarettes and patents EP2289356A1 , EP0990395A1 and US5000196A, for example, describe three different types.

The machines concerned are usually relatively complex and expensive. Also, their use has major negative aspects in terms of wasted time and energy in that the defective cigarettes must be collected, transferred to the machine which crushes them and separates out the different materials they are made of, and the tobacco recovered must be stored and then taken to the cigarette making machine which re-uses it.

Moreover, crushing the cigarettes or cutting the paper with a blade inevitably deteriorates the quality of the tobacco recovered, which is broken up into very short fibres containing a large amount of dust and which is therefore not very suitable for making good quality cigarettes.

Disclosure of the invention

The aim of this invention is to provide a method and a machine for making cigarettes, with recovery of tobacco from defective cigarettes, which overcomes the above mentioned disadvantages of the prior art.

The invention accordingly provides a method and a machine for making cigarettes, with recovery of tobacco from defective cigarettes, as in any of the appended claims.

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 front view of a part of a machine made according to this invention for making filter-tipped cigarettes; and

- Figure 2 is a schematic plan view of certain details of the machine of Figure 1 . Detailed description of preferred embodiments of the invention

With reference to Figure 1 , the numeral 1 denotes in its entirety a machine for making filter-tipped cigarettes 2, also known as filter tip assembling machine, of which only an outfeed portion 3 is shown.

The outfeed portion 3 comprises a roller 4 rotatable about a horizontal axis 5, located on the right in Figure 1 , and able to receive the filter-tipped cigarettes 2 in succession from a portion of the machine 1 (not illustrated) in which filter plugs are connected axially to respective cigarette sticks to make the filter-tipped cigarettes 2 themselves. On its cylindrical peripheral surface, the roller 4 has a plurality of equispaced flutes 6 which run parallel to the axis 5 of the roller itself and whose surface of contact with the cigarettes 2 is equipped in known manner with a plurality of ports connected to a source of suction, not illustrated, for holding the cigarettes 2 down in contact with the flutes 6 themselves along a portion of the path followed by the cigarettes 2 on the roller 4.

As it moves along on the roller 4, each cigarette 2 is subjected in known manner to one or more tests, such as, for example a permeability test, by a checking device 7.

The roller 4 transfers the cigarettes 2 in sequence to the suction flutes 8 of a further roller 9, which is mounted to rotate (clockwise in Figure 1 ) about an axis 10 parallel to the axis 5. The flutes 8 are equispaced along the cylindrical peripheral surface of the roller 9 and are identical to the flutes 6 of the roller 4.

The roller 9 in turn transfers the cigarettes 2 in sequence to the suction flutes 1 1 of a further roller 12, which is mounted to rotate (anticlockwise in Figure 1 ) about an axis 13 parallel to the axis 10. The flutes 1 1 are equispaced along the cylindrical peripheral surface of the roller 12 and are the same as the flutes 6 of the roller 4. The roller 12 is capable of transferring sample cigarettes 2, under the action of the checking device 7 or other checking units not illustrated, to respective suction flutes 14 of a sampling roller 15, which is rotatable (clockwise in Figure 1 ) about an axis 16 parallel to the axis 13, and feeds the cigarettes 2 received from the roller 12 into a container 17 from which these cigarettes 2 can be taken by an operator and tested outside the machine 1 . The flutes 14 are equispaced along the cylindrical peripheral surface of the roller 9 and are identical to the flutes 6 of the roller 4.

The roller 12 is also capable of sequentially transferring the cigarettes 2 transported by it to an outfeed conveyor 18 of known type, mounted substantially tangent to the roller 12 to receive the cigarettes 2 from the selfsame roller 12 and to transfer them by way of a chute 19 onto a bulk cigarette conveyor 20 positioned horizontally immediately downstream of the outfeed conveyor 18 and capable of feeding the cigarettes 2 towards a further handling unit not illustrated, consisting, for example, of a cigarette packing machine. In the example illustrated, the outfeed conveyor 18 comprises two parallel conveyor belts 21 and 22 defining between the respective transporting sections a channel 23 through which the cigarettes 2 pass as they are transported from the roller 12 towards the conveyor 20.

The roller 9 is capable of transferring the cigarettes 2 in sequence to the flutes 24 of a further roller 25, which is mounted to rotate (anticlockwise in Figure 1 ) about an axis 26 parallel to the axis 10. The flutes 24 are equispaced along the cylindrical peripheral surface of the roller 25 and are the same as the flutes 8 of the roller 9. The cylindrical surface of the roller 25 is mounted substantially tangent to the cylindrical surface of a further roller 27, counterrotating relative to the selfsame roller 25 about an axis 27' parallel to the axis 26 and located on the left of it in Figure 1 . The roller 27, too, has on its cylindrical peripheral surface a plurality of equispaced flutes 28 which are similar to the flutes 24 of the roller 25 and which may or may not be provided with suction means. Under the roller 25, at an expulsion station for expelling the defective cigarettes 2, there is a container 29 where the cigarettes 2 carried by the selfsame roller 25 are collected and whose function will become clearer as this description continues.

On one side of the zone 30 of substantial tangency between the rollers 25 and 27, at a station 30' which will hereinafter be referred to as "extraction station", there is an extractor device for the defective cigarettes 2 which, in the example illustrated in the accompanying drawings, comprises a blowing device 31 connected to a source 32 of compressed air (Figure 2). The blowing device 31 essentially comprises a drum 33 which is rotatable about a horizontal axis 34 perpendicular to the axes of rotation of the drums 25 and 27 and whose cylindrical peripheral surface is provided with a plurality of ports 35 which are angularly equispaced according to a spacing equal to the spacing of the flutes 24 and 28 of the rollers 25 and 27 and which can be placed in communication with the source 32 of compressed air, as explained below.

By way of example, the peripheral speeds of the rollers 4, 9, 12, 15, 25 and 27 and of the drum 33 may all be the same, with the flutes all angularly equispaced in the context of each roller/drum 4, 9, 12, 15, 25, 27, 33, or the spacing may be reduced so that the cigarettes on the drums 25 and 27 travel at reduced peripheral speeds so as to have more to empty them.

Located on the side of the zone 30 of substantial tangency between the rollers 25 and 27, opposite the side adjacent to the blowing device 31 , is the end of a duct 36 connected by way of a suction device 37 comprising, for example, a pump, to a tobacco infeed device (not illustrated) of a cigarette making machine schematically represented as a block 38. The cigarette making machine 38 is preferably connected to the machine 1 which assembles the filter plugs to respective cigarette sticks to make the cigarettes 2. In use, the cigarettes 2 found to be defective by the checking device 7 or by other checking devices (not illustrated) on the machine 1 are transferred in known manner from the flutes 8 of the roller 9 to respective flutes 24 of the roller 25, and sequentially reach the zone 30 of substantial tangency between the rollers 25 and 27.

On reaching the zone 30, each defective cigarette 2 is located between a flute 24 of the roller 25 which is transporting it and a flute 28 of the roller 27, and its filter tip is directed towards a port 35 of the drum 33 of the blowing device 31 . At that instant, the port 35 is placed in communication, in essentially known manner and preferably thanks to the action of activation means 7' of essentially known type serving the checking device 7, with the compressed air source 32 and blows a jet of air axially into the cigarette 2 located in the zone 30, through its filter tip in such a way as to push the tobacco in the cigarette 2 itself towards the end of the duct 36 so that the tobacco comes out of the paper. Thanks to its connection to the suction device 37, the duct 36, which constitutes a removal conveyor for moving away the tobacco of the defective cigarettes 2 sucks in the tobacco from the cigarette 2, moves it away from the rollers 25 and 27 and carries it to the tobacco infeed unit of the aforementioned cigarette making machine 38. It should be noted that during this operation, the cigarette 2 is held down firmly in contact with the conveyor means constituted by the rollers 25 and 27, and more specifically, is suitably held between the flutes 24 and 28 adjacent thereto so that it does not move under the action of the air jet. Thanks to this action on the defective cigarettes 2 from which the tobacco must be removed, the flutes 24 and 28 will also hereinafter be referred to as "hold-down means for the defective cigarettes 2 in the extraction station 30'.

As the roller 25 continues to rotate, the cigarettes 2 emptied of the tobacco in the manner described above reach the collection container 29 and from there can be removed from the machine 1 and scrapped. From the above it is evident that the machine 1 according to the invention and the operating method implemented by the machine are able to totally eliminate the disadvantages described above with reference to the prior art.

Indeed, the method described avoids the need to use a specific machine for crushing the defective cigarettes 2 and separating out the materials obtained, since the tobacco extracted from the defective cigarettes 2 is recovered immediately and recycled to the cigarette making machine 38 which makes the cigarettes 2.