WO2011107854A1 - Machine and method for making cigarette filters - Google Patents

Abstract

Machine and method for making segmented cigarette filters (2; 2a, 2b), according to which segments (3, 4) of several types are combined in various manners to obtain given successions of filter groups (16) of different compositions, applying to the segments (3, 4) given speeds and phases during their push-advancement along a combining device (15), which is provided with an inlet (44) for each type of segment (3; 4) and with an outlet (41) for the filter groups (16) and presents a succession of annular tracks (37-40) suitable to be followed in part by the segments (3, 4) and in part by the filter groups (16) and extending on a flat horizontal plate (17) for supporting and resting, in use, the segments (3, 4) and the filter groups (16); an initial distribution of the filter groups (16) at the outlet (41) being changed by imparting a controlled braking to the filter groups (16) during their transfer from the combining device (15) to a forming beam (55) of a continuous worm (60).

Description

MACHINE AND METHOD FOR MAKING CIGARETTE FILTERS

DESCRIPTION

The present invention relates to a machine and a method for making cigarette filters, in particular composite cigarette filters, i.e. filters comprising two or more segments of filtering material.

As it is well known, the above mentioned segments can be either arranged according to a continuous line, to form a succession of combined filters, or separated from one another by spaces, to form a succession of recess filters. The several segments can be made either of different filtering materials or of the same filtering material, which can be impregnated or not with liquid additives or, in general, with particulates, for instance in powder form.

The machines for making composite filters are usually of the type described in WO-2009/074540 and FR-1280722; they generally comprise a combining device provided with an inlet for each type of segment and with an outlet for filter elements comprising a combination of segments of the above mentioned segment types.

In the known machines of the type described above, the advancement of the segments through the combining device is obtained by means of rotating drums, which suck the segments, and therefore the obtained combinations of segments, and hold them inside their peripheral transport pockets. These sucking rollers not only are relatively complex from a structural viewpoint and expensive from an energy viewpoint, but they also make the machine relatively rigid, as changes in the format and/or distribution of the segments in the desired segment combinations can be obtained only by changing the drums and/or the positions of the inlets of the combining device.

The object of the present invention is to provide a machine and a method for making cigarette filters, in particular composite filters, that are easy and economical to be produced and, at the same time, guarantee high flexibility as regards changes in segment format and distribution and a relatively low energy consumption.

According to the present invention a machine is provided for making cigarette filters according to claim 1 and, preferably, according to any one of the claims depending directly or indirectly upon the claim 1.

According to the present invention a method is also provided for making cigarette filters according to claim 19 and, preferably, according to any one of the claims depending directly or indirectly upon the claim 19.

The present invention will be described hereafter with reference to the accompanying drawings, that illustrate some non limiting embodiments thereof, wherein:

- figure 1 is a side elevation view of a first preferred embodiment of the filter making machine of the present invention;

- figure 2 is a partial plan view in enlarged scale of the machine of figure 1;

- figure 3 is a perspective view in enlarged scale of a detail of figure 2;

- figure 4 is a perspective view in enlarged scale of a detail of figures 2 and 3, with some parts in cross- section and some parts removed for the sake of clarity;

- figure 5 is a schematic perspective view of a further detail of figures 2 and 3;

- figures 6 and 7 schematically illustrate respective filters that can be produced by means of the filter making machine of figure 1;

- figures 8, 9, and 10 schematically illustrate respective variants of the filter making machine of figure 1;

- figure 11 is a schematic view in enlarged scale, according to a perspective view analogous to that of figure 5, of a variant of the detail of figure 5; and

- figure 12 is an elevation view in enlarged scale of a detail of figure 11.

In figure 1, number 1 indicates, in its entirety, a machine for making cigarette filters, in particular cigarette composite filters.

According to what illustrated by way of example in figures 6 and 7, the machine 1 is suitable to produce a succession of double filters, generically indicated with the number 2, each of which comprises, in the present case, at least one segment 3 and at least one segment 4, which present equal lengths in the illustrated example but in reality can present different lengths. The segments 3 and 4 are arranged inside a tubular casing 5 either according to a continuous line, to define a succession of double filters 2 which must be subsequently cut to obtain combined filters 2a (figure 6) , or according to a line comprising spaces 6, to define a succession of double filters 2 which must be subsequently cut to obtain recess filters 2b (figure 7).

The segments 3 and 4 can be of different filtering materials or of the same filtering material, which is not impregnated for one of the two segments 3 and 4, while is impregnated with particulate material for the other of the two segments 3 and 4. Alternatively, the material of both the segments 3 and 4 can also be impregnated in different manners. In practice, the segment 3 can be made of cellulose acetate, while the segment 4 can be made of cellulose acetate impregnated with carbon dust.

The segments 3 and 4 are obtained by transversally cutting respective rods 7 (figure 5) extracted in a known manner from respective hoppers 8 and 9 by means of respective extracting and cutting units 10, each of which comprises an extracting roller 11 externally provided with axial grooves 12. The extracting roller is mounted for rotation, in counterclockwise direction in figure 1, around a horizontal axis 13; moreover, it is arranged to close an exit of the respective hopper 8, 9 and, along a part of its own periphery, into contact with the rods 7 contained in the respective hopper 8, 9. The grooves 12 are sucking grooves uniformly distributed around the axis 13 and each of them is suitable to receive and hold a respective rod 7, and to move this rod 7 along a circular path to extract it from the respective hopper 8, 9 and to engage it with a succession of cutting units 14, through which the rod 7 is cut into the respective segments 3, 4. In the illustrated example, associated with each extracting roller 11 there are three cutting units 14, each of which comprises, in a known and therefore not illustrated manner, a shaft parallel to the axis 13 and carrying keyed, in axially adjustable positions, more cutting disks suitable to engage the respective rods 7 moved forward from the extracting roller 11.

According to what is better illustrated in figures 2 and 3, in addition to the two hoppers 8 and 9 and to the extracting and cutting units 10, the machine 1 comprises a combining device 15 to combine segments 3 and 4 to obtain a cited ordered succession (figure 6 and 7) that can be chosen among a plurality of ordered successions obtainable by combining segments 3 and 4 of different dimensions and spaces 6, as the case may be.

As it will be better explained hereinafter, each of these ordered successions is obtained starting from the formation of a series of filter groups 16 through the combining device 15 and according to a given law variable from ordered succession to ordered succession; each of these filter groups 16, as it will be described hereafter, can be constituted even by a single segment 3 or 4 or part of it, and can be equal to, or different from, the two adjacent filter groups 16 preceding and, respectively, following it in the series.

According to what illustrated in figures 2 and 3, the combining device 15 comprises a rectangular plate 17 arranged horizontally and presenting a longitudinal rear edge 18, which is arranged transversally to the axes 13 and along which the adjacent hoppers 8 and 9 and the respective extracting and cutting groups 10 are mounted, and a longitudinal front edge 19, parallel to the longitudinal rear edge 18. The plate 17 is arranged at a lower level than that of the plane defined by the two axes 13 and presents an upper surface 20, whose plane is tangent to the outer surfaces of both the extracting rollers 11.

The combining device 15 furthermore comprises four wheels 21, 22, 23, and 24, wherein the wheels 21 and 24 are inlet wheels for respective feeding lines for the segments 3 and 4, the wheel 23 is a transferring wheel of the feeding line of the segments 4, and the wheel 22 is an outlet combining wheel coupled to both the cited feeding lines .

As the wheels 21-24 are of the same type, only the wheel 21 will be described in detail hereinafter. Obviously, the detailed description below applies to all the remaining wheels 22-24.

According to what illustrated in particular in figure 4, the wheel 21 comprises a shaft 25, which presents a vertical axis 26 perpendicular to the plate 17 and is mounted in a rotatable and axially fixed manner through a cylindrical sleeve 27 coaxial to the axis 26 and engaged in fixed position by means of a through hole 28 obtained in the plate 17. On a lower end of the shaft 25 projecting below the sleeve 27, a pulley 29 is keyed, which is carried into rotation, together with the other pulleys 29, by a belt 30 actuated by a motor 31. In particular, and with reference to figure 3, the pulley 30 is suitable to put the wheels 21 and 23 into counterclockwise rotation and the wheel 22 and 24 in clockwise rotation.

With regard to what mentioned above about the motorization of the wheels 22-24, it should be noted that, as it will be better described hereafter, the relative peripheral speed of ach wheel 22-24 relative to the other wheels is of major significance in management of the machine 1; and it should be furthermore noted that the configuration of figure 3, wherein all the pulleys 29 have the same diameter and the respective wheels 21-24 have therefore the same peripheral speed, can be suitable to obtain a particular double filter 2, for instance the double filter 2 of figure 6, while the use of pulleys 29, presenting different diameters, will be necessary for obtaining double filters 2 of different type.

In order to eliminate the drawback of changing the pulleys 29 for each format change, according to a not illustrated variant and for machines 1 designed not only for producing a single type of double filter 2, each of the wheels 22-24 is motorized through a respective motor, in particular an adjustable speed electric motor.

With reference to figure 4, to an upper end of the shaft 25 projecting above the sleeve 27 are fixed the inner ends of a plurality of radial tines 32, and the outer ends thereof are fixed, in a manner that can be disassembled, to a flat ring 33, which is coaxial to the axis 26 and is housed slidable inside an annular depression 34 obtained in the plate 17 coaxially to the axis 26 and through the upper surface 20 of the plate 17. Along the outer periphery of the depression 34 an annular groove is obtained, arranged outside the flat ring 33 and swept by a plurality of teeth 35, which project radially towards the outside of the flat ring 33, are uniformly distributed about the axis 26 and define a plurality of transport pockets 36.

According to what illustrated in figure 4, the grooves swept by the teeth 33 of the wheels 21 to 24 define respective annular tracks, respectively indicated with 37, 38, 39, and 40 and extending on the plate 17 coaxially to the respective axes 26, wherein the track 38 presents a first portion common to the track 37 and a second portion common to the track 39, which presents a portion common to the track 40. The tracks 37 and 40 are inlet tracks for the respective feeding lines of the segments 3 and 4, the track 39 is a transfer track of the feeding line of the segments 4 and the track 38 is an outlet track comprising a part, which is substantially tangent to the longitudinal front edge 19 of the plate 17, is arranged downstream of the cited second portion and upstream of the cited first portion of the track 38 in the direction of rotation of the wheel 22, and presents a radial opening which is an outlet 41 of the combining device 15.

According to what illustrated in figure 2, an appendix 42 extends outwards from each end of the longitudinal rear edge 18 of the plate 17; this appendix is perpendicular to the longitudinal rear edge 18, supports, together with a frame 43 for supporting the plate 17, the respective hopper 8, 9 and presents an upper surface coplanar with the upper surface 20 of the plate 17. Each appendix 42 extends below, and substantially tangentially to, the respective extracting roller 11 and is followed by a respective rectilinear slit 44, which is tangential to the respective wheel 21, 24 and extends along the plate 17 until it exits inside the respective track 37, 40. The slit 44 defines a rectilinear inlet track for the respective segments 3, 4 inside the combining device 15. In figure 2 it should be noted that the two slits 44 are parallel to each other, but they are inclined relative to the axes 13 of the respective extracting rollers 11. Namely, while each axis 13 is perpendicular to the longitudinal rear edge 18 of the plate 17 and is parallel to the peripheral grooves 12 of the respective extracting roller 11, each slit 44 is inclined forward, in the direction of rotation of the respective extracting roller 11 and relative to a peripheral groove 12 facing it, starting from a rear end of the peripheral groove 12.

Each of the slits 44 defines a feeding path for a succession of rods 7 extracted by the respective extracting roller 11 from the respective hopper 8, 9. According to what illustrated in particular in figure 5, each slit 44 is associated to a respective transport system 45, which is suitable to transfer the rods 7 from the respective extracting roller 11 to the respective track 37, 40 and comprises a conveyor 46 and an accelerating unit 47.

Each conveyor 46 is a pocket conveyor comprising a motorized annular chain 48, which presents a transport branch extending immediately below the respective slit 44 and is provided with teeth 49, which are movable along the slit 44, project above the upper surface 20 and are suitable to engage in a slidable manner respective peripheral grooves 12 of the respective extracting roller 11 when this latter rotates about the respective axis 13.

Each accelerating unit 47 comprises two motorized endless conveyors 50 and 51, which are arranged along the respective slit 44 at opposite sides of the plate 17 and present transport branches parallel to and facing one another, defining between themselves, and along the respective slit 44, an advancement channel 52 for the segments 3, 4 (or portions thereof) of the respective rods 7. In particular, the conveyor 50 is arranged below the plate 17 and its transport branch is coplanar, and aligned, with the transport branch of the chain 48 and presents an inlet rear end, which is joined, through a slab 53, to the front end of the transport branch of the respective conveyor 46.

As regards each transport system 43, the following applies :

1) V2/V1 = tang a; 2) V3 = V4 > V2

where :

a = angle of inclination of the slit 44 relative to the axis 13;

VI = peripheral speed of the extracting roller 11;

V2 = linear speed of advancement of the teeth 49;

V3 = linear speed of advancement of the conveyors 50 and 51;

V4 = linear speed of advancement of the teeth 35. Lastly, the machine 1 comprises an outlet section 54 of the substantially known type, which in turn comprises a forming beam 55, of the known type, supported by the frame 43 and arranged with an its own inlet portion along the longitudinal front edge 19 of the plate 17; a feeding unit 56, of the known type, for feeding a paper strip 57 that moves, in use, along the forming beam 55 in a direction 58 and defines a conveyor to advance, in the direction 58, the filtering material exiting from the outlet 41; a transfer group 59, of the known type, for transferring the filtering material from the combining device 15 to the forming beam 55 above the conveyor defined by the paper strip 57 for forming, along the forming beam 55 and in a known manner, a continuous filter worm 60; and a rotating cutting head 61, of the known type, suitable to cut transversally the continuous worm 60 to obtain a succession of segments, each of which corresponds to a double filter 2.

In the illustrated example of embodiment, the transfer group 59 is arranged above the level of the plate 17; however, a (non-illustrated) embodiment is also provided, according to which the transfer group 59 is arranged below the level of the plate 17; but in this case the transfer wheels constituting the transfer group 59 are more than three and comprise at least two further end wheels to bring the filtering material above the conveyor defined by the paper strip 57.

According to what illustrated in figure 2, the transfer group 59 comprises, in the illustrated example, three gear wheels 63, 64, and 65 of the centrifugal type, i.e. similar to that of the wheels 21-24. The wheels 63, 64, and 65 are rotatable about respective axes parallel to the axis 13, are arranged aligned on a vertical plane passing through the longitudinal front edge 19 of the plate 17, and are provided with respective transport pockets, each of which is suitable to receive a respective filter group 16, constituted by the content of a corresponding transport pocket 36 of the combining wheel 22. In particular, the wheel 63 is an inlet wheel, which is rotatable in phase with the combining wheel 22 and in clockwise direction in figure 2, and is arranged in a position tangential to the track 38 at the radial opening 41; the wheel 65 is an outlet wheel, which is rotatable clockwise in figure 2 and is arranged above the inlet of the forming beam 55 tangentially to the strip 57; and the wheel 64 is an intermediate wheel, which is tangential to the wheels 63 and 65 and is rotatable counterclockwise in figure 2 and in phase with the wheels 63 and 65.

Usually, the wheels 63 and 64 have a common motorization and rotate in phase with the combining wheel 22 and with a peripheral speed comprised between the peripheral speed VC of the combining wheel 22 and the speed VN of advancement of the strip 57. In general, the ratio between the peripheral speed of the wheels 63 and 64 and the peripheral speed of the combining wheel 22 is equal to the ratio between the length of the transport pockets of the wheels 63 and 64 and the length of the transport pockets 36 of the combining wheel 22.

Lastly, the wheel 65 (and in any case the last wheel of the transfer group 59) is usually provided with an independent motorisation and presents a peripheral speed VT, which is comprised between the peripheral speed of the wheels 63 and 64 and the speed VN of advancement of the strip 57.

In any case, the following always applies:

3) VOVN 4) VC≥VT 5) VT>VN In conclusion, in the case of the transfer group 59, the advancement of the filter groups 16 between the radial opening 41 and the forming beam 55 is therefore obtained by making a controlled braking, i.e. with a speed decreasing from the peripheral speed VC of the combining wheel 22 to the speed VN of the strip 57 by means of one, two, or three speed jumps. In use, each extracting roller 11 is put into counterclockwise rotation about the respective axis 13 with a constant peripheral speed VI, which can be different from the constant speed VI of the other extracting roller. During this rotation, each groove 12 takes a respective rod 7 and move it forward through the cutting unit 14, which transforms it into a succession of segments 3 or of segments 4 or of fractions thereof, adjacent to one another .

Each extracting roller 11 and the respective conveyor

46 are mutually synchronised so that, when a groove 12 is in a position facing the upper surface 20 of the plate 17 and tangential to it, the respective cut rod 7 enters transversally inside a transport pocket of the conveyor 46 and the tooth 49, which limits this pocket at the back, engages the rear end of the cited groove 12 and moves along this groove extracting the cut rod 7 and moving it towards the inlet of the channel 52 with the speed V2. This operation is possible thanks to the fact that the slit 44 and the transport branch of the conveyor 46 are inclined by the angle "a" relative to the groove 12, allowing the tooth 49 to follow the groove 12 even if the groove 12 continues to translate parallel to itself with the speed VI.

When the cut rod 7 achieves the inlet of the channel 52 (figure 5) , its first segment 3, 4 (or a fraction thereof) is taken by the conveyors 50 and 51, which accelerate it until the speed V3, detaching it from the subsequent segments 3, 4 and feeding it inside a respective transport pocket 36 of the wheel 21, 24, which moves with the speed V4 (that, as mentioned, is vectorially equal to V3 in the junction between the wheel 21, 24 and the respective accelerating unit 47). In particular, as regards the segments 3, the above mentioned transport pockets 36 are defined by the wheel 21 and move with the speed V4 , indicated hereinafter with V4a, along the track 37; as regards the segments 4, the above mentioned transport pockets 36 are defined instead by the wheel 24 and move with the speed V4b (which can be different from the speed V4a together with the respective speed V3) along the track 40.

The wheels 21-24 are synchronised with one another so that the segments 3 are directly transferred from a transport pocket 36 of the wheel 21 to a respective given position inside a transport pocket 36 of the wheel 22; and the segments 4 are transferred from a transport pocket 36 of the wheel 24 to a transport pocket 36 of the wheel 23 and then to a respective given position inside a transport pocket 36 of the wheel 22. The synchronisation of the wheels 21-24 is such that, immediately upstream of the outlet 41, the segments 3 and 4 are ordered, along the periphery of the combining wheel 22, according to a given order corresponding to that of the sequence to be formed on the forming beam 55.

Some examples will allow to better explain the operation of the combining device 15 and of its interaction with the transfer group 59 and with the conveyor defined by the strip 57 along the forming beam 55.

Example 1

This example relates to the formation of a sequence such as that illustrated in figure 6.

This sequence can be obtained according to three different methods.

Method 1

All the wheels 21-24 are actuated with a same peripheral speed V4 , but the wheel 21 is substantially in phase with the combining wheel 22, and the wheels 23 and 24 are in phase with one another, but slightly in advance relative to the combining wheel 22. This advance can be in the order of half the length of a transport pocket 36 of the combining wheel 22.

This setting allows each transport pocket 36 of the combining wheel 22 to receive from the wheel 21 a segment 3, which, once entered inside the cited transport pocket 36, immediately comes into contact with the rear tooth 35 of the transport pocket 36. Afterwards, the cited transport pocket 36 of the combining wheel 22 receives from the wheel 23 a segment 4, which moves in front of the respective segment 3 and comes immediately into contact with it to form a filter group 16, which is constituted by a segment 4 and a segment 3, in series and into contact with each other, and which coincides with a module 16a repeating the ordered succession to be formed along the forming beam 55. The cited filter group 16 presents a length Ll lower than a length L2 of the transport pocket 36 of the combining wheel 22, and the distance D between this filter group 16 and each of the adjacent filter groups 16 will be equal to:

6) D = L2 - Ll + K

where K is the thickness of a tooth 35.

The distance D is zeroed through a controlled "braking" obtained by means of at least one speed jump made during the transfer of the filter groups 16 from the combining wheel 22 to the forming beam 55.

The succession of figure 6 is therefore formed on the strip 57, and this succession, once it has been packed with the strip 57, is cut by the cutting head 61 into a succession of double filters 2, which will be then cut in two to obtain single filters 2a, on a subsequent filter- adder machine (not illustrated) .

Method 2

All the wheels 21, 23, and 24 are actuated with a same peripheral speed V4 , but the wheel 21 is out of phase relative to the wheels 23 and 24 by a distance equal to the length L2+K of the transport pocket 36 of the combining wheel 22; while the combining wheel 22 is actuated with a speed VC equal to the double of the speed V4 and so that inside one of the pockets of each pair of transport pockets 36 of the combining wheel 22 a filter group 16 is formed, constituted by a segment 3, and inside the other pocket a filter group 16 is formed, constituted by a segment 4.

Analogously to what described for the "Method 1", in this case again the distance between the filter groups 16 of the series exiting from the combining wheel 22 is zeroed by applying a controlled braking to the filter groups 16 during their transfer to the forming beam 55.

Method 3

The extracting and cutting group 10 is set so as to feed half a segment 3 inside each transport pocket 36 of the wheel 21; furthermore, the wheels 21 and 22 are actuated with a same peripheral speed V4 and in phase with each other, while the wheels 23 and 24 are actuated with a speed equal to half the speed V4.

In this way it is possible to feed half segment 3 inside each transport pocket 36 of the combining wheel 22, while alternating transport pockets 36 of the combining wheel 22 receive also a segment 4.

By subsequently compacting the two different filter groups 16, the sequence of figure 6 is obtained.

As the filter group 16 constituted by half segment 3 is, in this case, shorter than the filter group 16 constituted by half segment 3 and a segment 4, using the "Method 3" and applying a different controlled braking it will be possible to obtain a sequence (not illustrated) enabling the production of double filters 2, which comprise, in succession, a half segment 4, a half segment 3, a space S, a half segment 3 and a half segment 4. Each of these double filters 2 can be therefore cut into two halves to obtain a pair of cigarette filters, each of which comprising a half space S (mouth side) , a half segment 3 and a half segment 4 (cigarette side) .

This result will be obviously always possible only if the length S of the cited space 6 in lower than half of the length of the segment 3.

Example 2

This example relates to the formation of a sequence such as that illustrated in figure 7.

This sequence is obtained by using the "Method 2" of the example 1, with the only difference that the braking of the filter groups 16 during their transfer to the forming beam 55 is limited so that the filter groups 16 are not compacted, as in the case of the cited "method 2", at the inlet of the conveyor defined by the strip 57, but they are arranged on it spaced from one another by a distance S equal to the length of the space 6.

From the examples above it is clearly apparent that on the machine 1 the double filters 2 are produced in two distinct phases, the first of which, performed by the combining device 15, is a phase of combining and ordering segments 3 and 4 to form, inside the transport pockets 36 of the wheel 22, a succession of filter groups 16, whose structures and order are a function of the reciprocal phasing and of the relative speeds of the wheels 21-24; and the second of which, performed by moving forward the filter groups 16 from the combining device 15 to the cutting head 61, is a composing and cutting phase, during which the initial distribution of the filter groups 16, imposed by the distribution of the transport pockets 36 of the combining wheel 22, is changed by imparting a controlled braking to the filter groups 16 during their transfer from the combining device 15 to the forming beam 55, and setting this braking it is possible to obtain compact sequences for producing filters 2a or recess sequences for producing filters 2b.

The filter groups 16 are maintained, in a known manner and through suction, in their end relative positions during their advancement along the conveyor defined by the strip 57, which, moving forward along the forming beam 55, is folded, in a known manner, transversally around the succession of filter groups 16 to form the filter worm 60, which is fed with continuous motion through a cutting station, wherein the cutting head 61 cuts the worm 60 to form the double filters 2.

It is clearly apparent that, if the aim is to produce compact sequences, the transferring group 59 can be replaced, in a not illustrated manner, with a simple conveyor compactor of the known type.

With respect to the known filter machines, the machine 1 described above presents some distinctive features constituted by the facts that:

- once the segments 3 and 4 have achieved the plate 17, they move, resting on a horizontal plane and being pushed (without being held through suction) , both when they are fed to the combining device 15 along the slits 44 and when they move along the combining device 15;

- the filter groups 16 exiting from the combining device 15, push-advance along the transferring group 59 separated from one another by distances defined by the dimensions of the transport pockets of the wheels 63-65;

- the composition of the filter groups 16, and therefore of the succession formed on the conveyor defined by the strip 57, can be varied simply by adjusting the phasing and the peripheral speeds of the wheels 22-24;

- the reciprocal positions of the filter groups 16 and the formation of spaces S, if any, are adjusted absolutely without controlling, through suction and/or through the insertion of teeth of width S, the position of the filter groups 16 along the transferring group 59, but simply by controlling the speed of the filter groups 16 applying a controlled braking to them during their transfer from the combining device 15 to the conveyor defined by the strip 57; and

- the format changes do not require the mounting and demounting of cylindrical drums keyed on respective shafts, but simply the replacement of the flat rings 33.

The variants illustrated in figures 8 to 10 relate to machines, indicated respectively with 66, 67, and 68, for making four-segment filters (not illustrated) . In particular, the machine 66 substantially corresponds to two machines 1, wherein the plates 17 have been made integral to one another along their longitudinal front edges 19 to form a single plate 69, the hoppers for the rods 7 are four, are generically indicated with the number 70 and are arranged in pairs at opposite sides of the plate 69, and there are two series of wheels 21-24, wherein the two combining wheels 22 are tangential to each other and share the radial opening 41. In the machine 66 there are a single outlet section 54 with a single forming beam 55, a single feeding unit 56 for feeding a single paper strip 57 and a single transfer group 59 for transferring the filter groups (not illustrated) from the single outlet 41 to the forming beam 55 above the strip 57 to produce on the paper strip 57 ordered successions (not illustrated) comprising four types of segments compacted together or spaced.

In the machine 67, the four hoppers 70 are arranged in pairs along the branches of a L and along two contiguous edges of a plate 71 supporting eight wheels, generically indicated with the number 72, similar to the wheels 21-24, one of which, indicated with 72a, is a combining wheel allowing the formation, on a single not illustrated forming beam, of ordered successions (not illustrated) comprising four types of segment compacted together or spaced.

Lastly, in the machine 68 the four hoppers 70 are arranged in pairs along the branches of a T and along two contiguous edges of a plate 73 supporting nine wheels, generically indicated with the number 74, similar to the wheels 21-24, one of which, indicated with 74a, is a combining wheel allowing the formation, on a single not illustrated forming beam, of ordered successions (not illustrated) comprising four types of segments compacted together or spaced.

Observing the diagrams of the machines 66, 67, and 68 it is immediately clear that each of these machines is constituted by two mutually integrated modules, and that each of these modules is constituted by a machine 1, that has its own plate 17 common to the other machine 1.

In particular, it should be noted that:

- in the machine 66, the outlets of both the modules are mutually combined on the transfer group 59;

- in the machine 67, the outlet of one of the two modules is connected with an intermediate track of the combining device of the other module; and

- in the machine 68, the outlet of one of the modules is directly connected to the transfer group 59, while the outlet of the other module is connected to the transfer group 59 through the combining wheel 74a that is, in this case, an additional wheel.

In view of the above description it is easily understood that, if one desires to produce filters with two ore more segments and machines 1 are available, it is always possible to combine in various manner, according to not illustrated variants, at least two machines 1 using a single transfer group 59, connecting the outlet 41 of one first of the machines 1 directly to the transfer group 59, and connecting the outlet of the second machine 1 with any one of the tracks 37-40 of the combining device 15 of the first machine 1 or with the transfer group 59. Obviously, these connections can be either direct or produced indirectly through the interposition of a conveyor, preferably constituted by a train of pocket wheels, which can be even wheels with vertical axis devoid of suction or, due to space reasons, suction pocket wheels with horizontal axis.

The variant illustrated in figures 11 and 12 relates to a different accelerating unit, indicated with the number 47a, suitable to be used instead of each accelerating unit 47 and, analogously to this latter, to receive in succession the rods 7 from the chain 48 and to accelerate the respective segments 3, 4 to feed them singularly to the transport pockets 36 of the respective wheel 21, 24.

Each accelerating unit 47a comprises two conveyors 50a and 51a, which are arranged along the respective slit 44 at opposite sides of the plate 17 and which define between themselves along the slit 44 the advancement channel 52 for the segments 3, 4 of the respective rods 7.

In particular, the conveyor 50a is arranged below the plate 17 and comprises two disks 75, which are motorized, to rotate in opposite directions around respective axes 76 extending perpendicularly to the plate 17, and are arranged substantially tangential to one another. The disks 75 are arranged coplanar to one another and to the transport branch of the chain 48 and at opposite sides of the elongation of the transport branch, and they are externally limited by respective frusto-conical surfaces 77, which are arranged with their conicities facing upwards and define, between themselves and at the zone of substantial tangency, a lower surface portion of the channel (52) . The actuation of the disks 75 is such that, in use, the peripheral speeds V3 of the frusto-conical surfaces 77 at their zone of substantial tangency are equal to one another and concordant with the linear speed V2 of advancement of the teeth 49 of the chain 48.

The conveyor 51a is arranged above the plate 17 and comprises a pulley 78, which is motorized to rotate around an axis 79 parallel to the plate 17, perpendicular to the axes 76 and extending on a plane defined by the axes 76. The pulley 78 is directly arranged above the zone of substantial tangency of the disks 75 and presents an outer annular groove 80, whose peripheral speed V3 is equal to, and concordant with, in the zone of substantial tangency of the disks 75, the peripheral speed V3 of the disks 75 and defines, at the zone of substantial tangency of the disks 75, an upper surface portion of the channel 52.

Claims

1. A filter making machine for making segmented cigarette filters (2; 2a; 2b), the machine (1) comprising a first portion for combining a number of filter segments (3, 4) and a second portion for composing and cutting the filters (2; 2a; 2b); the first portion comprising at least a combining device (15) to combine several types of filter segment (3, 4) made of several types of filtering material to obtain a succession of segmented filter groups (16), the combining device (15) having an inlet (44) for each type of filter segment (3, 4) and an outlet (41) for the filter groups (16); and the machine (1) being characterized in that the combining device (15) comprises an horizontal plate (17) having, at the upper side, a succession of tracks (37-40) adapted to be followed in part by the segments (3, 4) and in part by the filter groups (16); the plate (17) defining a rest and support surface for the filter segments (3, 4) and the filter groups (16) which move, in use, along the tracks (37-40); each track (37; 38; 39; 40) being tangent to, and communicating with, each adjacent track (37; 38; 39; 40); and the inlets (44) and the outlet (41) being associated to respective tracks (37, 40; 38) .

2. The filter making machine claimed in Claim 1, wherein each track (37; 38; 39; 40) is an annular track extending about a respective axis (26) which is perpendicular to the plate (17); wheel means (21; 22; 23; 24) being carried by the plate (17) coaxially to said axis (26) to advance the filter segments (3, 4) and/or the filter groups (16) along the track (37; 38; 39; 40).

3. The filter making machine claimed in Claim 2, wherein, for each said track (37; 38; 39; 40), the wheel means (21; 22; 23; 24) comprise a motorized flat ring (33) which is coaxial to said axis (26) and has a plurality of teeth (35) for sweeping the track (37; 38; 39; 40), the teeth (45).

4. The filter making machine claimed in Claim 2 or 3, and further comprising at least two hoppers (8, 9) for respective types of filter segment (3; 4); each hopper (8; 9) being associated to a respective inlet (44) which comprises a straight track extending, at least in part, along the plate (17) and tangent to a respective said annular track (37; 40), which is an inlet track (37; 40) for the combining device (15); extracting means (11) being provided for extracting the filter segments (3, 4) from each hopper (8, 9); and conveyor means (45) being movable along the straight track for conveying the filter segments (3, 4) from the extracting means (11) to the respective inlet track (37; 40) .

5. The filter making machine claimed in Claim 4, wherein each hopper (8, 9) is designed to accommodate a plurality of filter rods (7) of a respective type of filtering material; the extracting means (11) comprising, for each hopper (8, 9), a motorized extracting roller (11) mounted for rotation about a horizontal axis (13) and having peripheral axial grooves (12) each adapted to receive and retain a respective said filter rod (7).

6. The filter making machine as claimed in Claim 5, wherein cutting means (14) are provided to cut each filter rod (7) into the respective segments (3; 4) when the filter rod (7) is displaced, in use, by the relevant extracting roller (11) .

7. The filter making machine claimed in Claim 5 or 6, wherein each extracting roller (11) is arranged above, and tangent to, the respective straight track; the conveying means (45) comprising an endless conveyor (46), which is synchronized with the respective extracting roller (11) and has a succession of teeth (49) , each of which is adapted to move, in use, along a respective axial groove (12) and the respective straight track.

8. The filter making machine claimed in Claim 7, wherein each said straight track is defined by a respective slit

(44) provided through the plate (17); the respective endless conveyor (46) being arranged below the plate (17).

9. The filter making machine claimed in Claim 7 or 8, wherein each extracting roller (11) is mounted for continuous rotation about the respective axis (13) in a predetermined direction and with a predetermined constant speed of rotation; the respective straight track being inclined, in relation to said axis (13), by an angle (a), the amplitude of which is a function of said speed of rotation.

10. The filter making machine claimed in one of Claims 2 to 9, wherein the annular tracks (37-40) comprise at least a pair of inlet tracks (37, 40) connected to respective said inlets (44) to receive respective types of filter segment (3; 4), at least one combining track (38) associated with the inlet tracks (37, 40), and at least a transfer track (39) interposed between the combining track (38) and a respective inlet track (40); the wheel means (21; 22; 23; 24) comprising, for each said annular track (37; 38; 39; 40) , a motorized flat ring (33) which is coaxial to said axis (26) and has a plurality of teeth (35) for sweeping the respective annular track (37; 38; 39; 40); the teeth (35) defining a succession of transport pockets (36), which are movable along the annular track (37; 38; 39; 40) for receiving, each, a respective filter segment (3; 4) or a respective filter group (16) .

11. The filter making machine claimed in Claim 10, wherein the transport pockets (36) movable along the inlet tracks (37, 40) and the transport pockets (36) movable along the transfer track (39) are phased with one another and with the transport pockets (36) movable along the combining track (38) to feed the filter segments (3, 4) to respective transport pockets (36) movable along the combining track (38) at determined positions and with a determined succession order chosen from a number of different combinations of position and succession order.

12. The filter making machine claimed in Claims 4 and 11, wherein the conveying means (45) further comprise an accelerating unit (47; 47a) adapted to receive a respective said rod (7) and to separate the respective filter segments (3; 4) from one another to feed them in succession to the respective said transport pockets (36) movable along the respective inlet track (37; 40).

13. The filter making machine claimed in Claims 8 and 12, wherein the accelerating unit (47; 47a) comprises a first and a second motorized conveyor (50, 51; 50a, 51a) , which are arranged along the respective said slit (44) the first below and the second above the plate (17) and define therebetween, and along the respective slit (44), an advancement channel (52) for the filter segments (3; 4) of the respective filter rods (7).

14. The filter making machine claimed in Claim 13, wherein the first and second conveyor (50, 51) of the accelerating unit (47) are endless conveyors having respective parallel transport branches which face one another; the transport branch of the first conveyor (50) defining a lower side, and the transport branch of the second conveyor (51) defining an upper side, of said channel (52).

15. The filter making machine claimed in Claim 13, wherein the first conveyor (50a) is arranged below the plate (17) and comprises two coplanar disks (75), which are motorized to rotate in opposite directions about respective first axes (76) extending perpendicularly to the plate (17), have frusto-conical peripheries which extend through a zone of substantial tangency of the disks (75) to one another and are arranged with their conicities facing upwards to define, therebetween and at the zone of substantial tangency, a lower surface portion of the channel (52).

16. The filter making machine claimed in Claim 15, wherein the second conveyor (51a) is arranged above the plate (17) and comprises a pulley (78), which is motorized to rotate about a second axis (79) parallel to the plate (17), perpendicular to the first axes (76) and extending on a plane defined by the first axes (76); the pulley (78) having an outer annular groove (80) defining, at said zone of substantial tangency, an upper surface portion of the channel ( 52 ) .

17. The filter making machine as claimed in one of the foregoing Claims, wherein said second portion comprises a forming beam (55) for forming a continuous filter worm (60); a feeding unit (56) for feeding a paper strip (57) along the forming beam (55); a transfer group (59) for push-transferring the filter group (16) from said outlet (41) to the forming beam (55) above the strip (57); and a cutting head (61) for cutting the continuous worm (60) to obtain said filters (2).

18. The filter making machine claimed in Claim 17, wherein feeding means (56) are provided to feed, in use, the paper strip (57) along the forming beam (55) at a speed (VN) lower than a speed (VC) of the filtering groups (16) at the outlet (41) of the combining device (15).

19. A method for making segmented cigarette filters (2; 2a; 2b) , the method comprising a first step for combining a number of filter segments (3, 4) together and a second step for composing and cutting the filters (2; 2a; 2b); the first step comprising:

- providing at least a combining device (15) to combine several types of filter segment (3, 4) made of several types of filtering material to obtain a succession of segmented filter groups (16) having respective compositions; the combining device (15) having an inlet (44) for each type of filter segment (3, 4), an outlet (41) for the filter groups (16), and a succession of tracks (37- 40) extending on a horizontal plane and adapted to be followed in part by the segments (3, 4) and in part by the filter groups (16); each track (37; 38; 39; 40) being tangent to, and communicating with, each adjacent track (37; 38; 39; 40); the inlets (44) being associated to respective inlet tracks (37, 40), and the outlet (41) being associated to a combining track (38);

- pushing the filter segments (3; 4) along the respective tracks (37; 40, 39), and inside respective first transfer pockets (36) , by moving the first transfer pockets (36) along the tracks (37; 40, 39) at respective first speeds (V4) to feed the filter segments (3, 4) to second transfer pockets (36) arranged for movement along the combining track (38) at a second speed (VC) to form, within the second transfer pockets (36), said filter groups (16) arranged in said succession along the combining track (38) ; the composition of each filter group (16) being controlled by varying said first and second speed (V4, VC) and/or the phases of the first and second pockets (36) ; and

- push-advancing the filter groups (16) along the combining track (38) up to their leaving, in said succession, the combining device (15) trough said outlet (41) .

20. The method claimed in Claim 19, wherein the second step comprises :

- feeding the filter groups (16) through said outlet (41) in said succession, at said second speed (VC) and aligned in a predetermined first space relationship, to a transfer group (59) of the filter groups (16);

- feeding, at an adjustable third speed (VN) lower than the second speed (VC) , a paper strip (57) along a forming beam (55) for a filter continuous worm (60);

- push-advancing, by means of the transfer group (59), the filter groups (16), arranged in said succession, from said outlet (41) to the forming beam (55) and above the paper strip (57) ;

- applying to the filter groups (16), during their transfer from said outlet (41) to the forming beam (55), a controlled braking so as to order the filter groups (16) on the paper strip (57) and along the continuous filter worm (60), according to said succession, but aligned in a predetermined second space relationship more compacted than the first space relationship; - feeding the continuous filter worm (60) at said third speed (VN) to a cutting head (61) to cut the continuous filter worm (60) into filter segments (2) each comprising two counterposed cigarette filters (2a, 2b) .

21. The method claimed in Claim 20, wherein said controlled braking is obtained by means of a speed jump at the passage of the filter groups (16) from the transfer group (59) to the forming beam (55) .

22. The method claimed in Claim 20, wherein said controlled braking is obtained by means of a number of speed jumps, of which one is applied when transferring the filter groups (16) from the transfer group (59) to the forming beam (55), and another is applied when transferring the filter groups (16) from the combining device (15) to the transfer group (59) or when advancing the filter groups (16) along the transfer group (59) .