A rolling method and a relative device for filter tipping machines

Abstract: An assembly (4) comprising two lengths of cigarette rod (5), a double length filter (6) and a band of gummed paper (7) is rolled up along a path describing a limited arc (8) to produce a double length filter tipped cigarette (9), passing between a cylindrical inner rolling surface (21) and a cylindrical outer conveying surface (46) which revolve in the same direction about respective axes (15, 24), the inner surface (21) at a greater velocity than the outer surface (46). The conveying surface (46) is generated by a succession of substantially flat faces (43), each affording a seat (49) shaped to accommodate a relative assembly (4) and incorporated laterally into one of a series of rockers (42) mounted so as to pivot between a first position, assumed along the rolling arc (8), in which the flat faces (43) are directed toward the rolling surface (21), and a second position assumed when passing through successive infeed and outfeed stations (3, 10), in which the flat faces (43) are directed away from the rolling surface.

Description: The present invention relates to a rolling method for filter tipping machines. Filter tipping machines in current use are designed normally to receive a succession of double length cigarette rods from a cigarette manufacturing machine, which are cut crosswise into equal parts to produce two single lengths. The single lengths of each pair generated in this way are distanced one from another axially, opening up a space sufficient to accommodate a double length filter which combines thus with the two lengths of cigarette rod to form an "assembly" of elongated elements disposed in axial alignment one with another, such as can be joined rigidly together to produce a double length cigarette. It is a conventional practice when fashioning double length cigarettes in this way to advance each assembly together with a band of gummed paper marginally longer than the double length filter, attached along one edge to the central portion of the relative assembly, which is wrapped around the assembled elements internally of a rolling device. Rolling devices embraced by the prior art generally comprise a rolling drum, by which the assemblies and the relative bands of gummed paper are directed in succession into a rolling channel afforded between a fixed restraint and a peripheral surface of the drum, The restraint is compassed within a comparatively small arc of the overall circumference presented by the drum, typically 60° or thereabouts, and separated from the peripheral surface by a distance marginally less than the diameter of the double length filter. As a result of the initial impact produced on engaging the fixed restraint, then of frictional contact with the restraint on the one hand and with the peripheral surface of the drum on the other, each successive assembly is forced to roll about its own axis, causing the relative band of gummed paper thus to envelop the double length filter and a portion of the cigarette rod on each side, while advancing along the rolling channel at a feed velocity equivalent to half the peripheral velocity of the drum. It is also known from document EP-A-0599162 a rolling apparatus for filter assembly machines comprising a rolling device provided for joining, by means of a succession of strips, a number of elongated elements. A number of rollers, each presenting a respective seat for a respective group, rotates about a respective axis and rolls the groups in contact with a rolling surface. The axes of the rollers are moved, in relation to the rolling surface, at a first speed and the rollers are so operated as to rotate about the respective axes and advance the respective seats at a secon variable speed which is minimum when the groups are loaded and unloaded on and off the rollers. Conventional rolling devices of the type described above betray certain drawbacks attributable mainly to the ever increasing output capacity of filter tipping machines, and consequently the higher and higher speed at which the cigarecte rod and filter assemblies need to be conveyed; the cigarette rods tend co break open on striking the entry end of the fixed restraint, and to empty thereafter by reason of the relatively high speeds of rotation (5000 rev/min) generated along the rolling channel. The object of the present invention is to provide a method and rolling method a relative device for filter tipping machines as described in claims 1 and 7. The invention will now be described in detail, by way of example, with the aid of the accompanying drawings, in which: fig 1 shows a preferred embodiment of the rolling device according to the present invention, illustrated in a side elevation with parts in section; fig 2 is an enlarged detail of fig 1; fig 3 is a schematic section on III-III in fig 1 with parts omitted for clarity; fig 4 is an enlarged section on IV-IV in fig 2. Referring to figs 1 and 2 of the drawings, 1 denotes a filter-tipping machine, in its entirety, incorporating a fixed frame la (fig 3), and supported by the frame, a rolling unit 2 positioned to cake up a succession of assemblies 4, each comprising two lengths of cigarette rod 5, a double length filter 6 separating the rods 5, and a gummed paper 7 serving to connect each rod 5 to a corresponding end of the double length filter 6, in accordance with standard practice. Directed onto the unit 2 by way of an infeed station 3, the assemblies 4 are advanced along a rolling arc denoted 8, and caused in the process to rotate in such a way that the gummed papers 7 will wrap around the respective rods 5 and double length filters 6 to form a succession of double length cigarettes 9 which are directed by the unit 2 toward an outfeed station 10. The machine 1 further comprises an aspirating infeed roller 11 of conventional embodiment, rotatable about a respective axis (perpendicular to the plane of fig 1 though not indicated) in an anticlockwise direction, as viewed in fig 1, from which the assemblies 4 are transferred singly and in succession to the rolling unit 2 at the infeed station 3, also an aspirating outfeed roller 12 lying tangential to the unit 2 at the outfeed station 10, rotatable about a respective axis (perpendicular to the plane of fig 1, though not indicated) in an anticlockwise direction as viewed in fig 1, by which the double length cigarettes 9 are taken up singly and in succession from the unit 2. As discernible in fig 1, the infeed roller 11 rotates tangentially to the rolling unit 2 at the relative station 3 and is furnished with a plurality of vacuum slots 13 distributed uniformly around the periphery, each designed to accommodate and retain one assembly 4 disposed with the relative rods 5 and double length filter 6 occupying the space afforded by the slot 13, and with the relative gummed paper 7 trailing behind, attached tangentially to the double length filter 6 and the two rods 5 along a common generator farthest removed from the slot 13. As indicated in fig 3, the unit 2 comprises a shaft 14 rotatable about an axis 15 perpendicular to the plane of fig 1, also a gear wheel 16 keyed to one end of the shaft 14 and engaged in mesh with a pinion 17 by which the shaft is driven in rotation about the axis 15 at a constant angular velocity, turning clockwise as viewed in fig 1. The unit 2 further comprises a fixed cam 18 of drum like appearance which affords a through axial hole 19 aligned coaxially with the axis of rotation 15 and freely accommodating the shaft 14, also a drum 20 rigidly associated with the end of the shaft 14 remote from the end keyed to the gear wheel 16 and compassed externally by a cylindrical rolling surface 21, which in a preferred embodiment will be milled and furnished with a plurality of rotation-inducing axial grooves 22 distributed uniformly around the periphery, although the grooves might be omitted. Still referring to fig 3, the unit 2 also comprises a cylindrical cage 23 supported in conventional manner (not indicated) and rotatable about an axis 24 which, as illustrated in fig 1, is disposed parallel with but marginally offset from the axis 15 of the drum 20. The cage 23 comprises two rings 25 and 26 centred on the same axis 24, the first of which affording a clearance hole 27 concentric also with the axis 24 and occupied rotatably by an appendage 28 that extends axially from the cam 18, likewise concentrically with the axis 24, and is occupied in its turn by the shaft 14. As illustrated to better advantage in fig 4, the two rings 25 and 26 are interconnected by a plurality of shafts 29, each of which disposed with its opposite ends anchored rotatably in relative sockets 30 and 31 afforded respectively by the two rings 25 and 26 and rotatable thus about a corresponding axis 32 parallel to the two central axes 15 and 24. The end of each shaft 29 occupying the socket denoted 30 is coupled to an actuator device 33 by which the shaft 29 itself can be made to rock on its axis 32; the device 33 operates in conjunction with the cam 18 and further comprises a multiple thread screw 34 rigidly associated with the shaft 29 and rotatable about the same axis 32, also a lead nut 35 coupled with the screw 34 and presenting a radial appendage denoted 36. The appendage 36 affords a clearance hole 37 disposed parallel to the screw 34, slidably accommodating a rotation-inhibiting rod 38 associated rigidly with the ring 25, and carries a pivot 39 extending at right angles to the screw 34 on which to mount a freely rotatable following roller 40 located in an annular groove 41 afforded by the cam 18 and encircling the axis 15 of rotation. With reference to figs 2 and 4 of the drawings, each shaft 29 carries a keyed rocker element 42 exhibiting what is essentially a peardrop transverse profile, of which one side presents a substantially flat face 43 parallel with the axis 32 of the shaft; the rocker 42 appears essentially rectangular in plan (fig 4), with a longitudinal axis positioned parallel and laterally offset relative to the axis 32 of the shaft. The flat face 43 of the rocker 42 is compassed laterally by two opposite longitudinal edges affording respective sets of teeth 44 and 45 staggered one from another. Each rocker 42 is caused by the relative actuator device 33 to rotate about the relative axis 32 between two angular positions 180° apart. In a first of these two positions, the flat face 43 is directed toward the drum 20, in such a way as to generate a segment of a concave cylindrical surface 46 centred on the axis 24 of the cage 23, directed toward the rolling surface 21 and combining with this same surface 21 to establish a rolling channel 47; as discernible from fig 2, the teeth 44 of one rocker 42 are designed to interlock with the teeth 45 of the next and thus to maintain the continuity of the concave surface 46. In the second position, rotated 180° about the shaft 29, the flat face 43 is directed away from the rolling surface 21 to form a segment of a convex cylindrical surface 48 centred on the axis 24 of the cage 23, the teeth 44 of one rocker 42 again interlocking with the teeth 45 of the next to maintain the continuity of the surface 48. The flat face 43 of each rocker 42 incorporates a longitudinal seat 49 extending adjacent to one set of teeth 44, parallel to the axis 32 of the shaft 29, and designed to accommodate a single assembly 4 which is held in place by a line of holes 50 forming part of a conventional suction device 51. The shaft 29 functions as a rotating coupler for the suction device 51, which also comprises a second line of holes 52 extending adjacent to the opposite set of teeth 45 and operating in conjunction with certain of the first holes 50 to keep the gummed paper 7 of the relative assembly 4 in contact with the flat face 43 by restraining the two opposite edges of the band. Referring again to fig 3, the unit 2 comprises drive means 53 connecting with the gear wheel 16 on the one hand and with an external tooth profile 54 afforded by the nearer ring 25 on the other; such means 53 include a shaft 55 supported by the frame la, rotatable about an axis 56 parallel with the axis 15 of the drum 20, a first gear 57 keyed to the shaft 55 and in mesh with the gear wheel 16, and a second gear 58 keyed to the shaft 55 and in mesh with the tooth profile 54. The drive means 53 are arranged in such a way as to set the surfaces 21 and 46 of the channel 47 in rotation in the same direction about their respective axes 15 and 24, and proportioned such that the cage 23 will rotate at an angular velocity less than the angular velocity of the drum 20 driven by the shaft 14. Still referring to fig 3, the shaft 14 is associated with the gear wheel 16 by way of an axially slidable coupling 59 that enables the drum 20 to be distanced axially from the cage 23 for the purposes of cleaning, maintenance or product changeover. The operation of the unit 2 will now be described, following the progress of a single rocker 42 from the moment of its passage, with the cage 23 rotating at a uniform angular velocity about the relative axis 24, beyond the outfeed station 10 and toward the infeed station 3 at the same constant velocity. At this stage the rocker 42 is positioned with the flat face 43 directed away from the axis 24, thus combining with the surfaces 43 of adjacent rockers 42 as described above to generate the convex surface 48, which revolves substantially tangential to the two aspirating rollers 11 and 12 at the corresponding stations 3 and 10. The rocker 42 continues to advance in this position, with the set of teeth denoted 44 forwardmost, and enters the infeed station 3 with the longitudinal seat 49 timed to encounter a slot 13 of the relative roller 11, whereupon an assembly 4 is transferred in conventional manner to the seat 49 and retained. More precisely, as indicated in fig 4, the assembly 4 is caused to settle on the rocker 42 with the relative gummed paper 7 spread across the flat face 43 and held in place through the effect of suction generated by the relative device 51 via the holes 52 on the one side and certain of the holes 50 on the opposite side, and with the cigarette rods 5 and the double length filter 6 occupying the seat 49. Having cleared the infeed station 3, the rocker 42 is caused to pivot anticlockwise about its axis 32 of rotation by the corresponding actuator device 33, of which the lead nut 35 will be translated axially by the cam 18 in such a way that the relative screw 34 and the associated shaft 29 are forced to rotate. The rocker 42 completes a rotation of approximately 180° about the relative axis 32 before entering the rolling arc 8, with the result that the flat face 43 assumes and remains in a position addressing the surface 21 of the drum, combining with the surfaces 43 of adjacent rockers 42 to generate the concave surface 46. Within the compass of the rolling arc 8, this same surface 46 combines with the surface 21 of the drum to establish a rolling channel 47 which, given that the two surfaces 46 and 21 are not concentric, affords an entry gap and an exit gap of width marginally greater than the diameter of the assemblies 4, and a tighter intermediate section of width marginally less than the diameter of the assemblies 4. Thus, when carried into the channel 47 by the relative rocker 42 and brought gradually into contact with the revolving surface 21 of the drum, which turns in the same direction as the rocker 42 but at a greater velocity, the assembly 4 is forced from the seat 49 and rolled against the flat face 43, following an arcuate trajectory concentric with the axis 15 of the drum and advancing, relative to the rocker 42, at a velocity half way between the peripheral velocities of the two revolving surfaces 21 and 46. As discernible in fig 4, the rolling action induced between the assembly 4 and the flat face 43 of the relative rocker 42 is in itself sufficient to complete the formation of the double length cigarette 9; this said, best results are achieved when the difference between the velocities of the two surfaces 21 and 46 is relatively small, and yet great enough to ensure that the assembly 4 will complete two full revolutions about its own axis when passing along the channel 47. On completion of the rolling step, the double length cigarette 9 exits the channel 47 no longer associated with the rocker 42 occupied initially by the relative assembly 4, but occupying the seat 49 afforded by the rocker 42 two places forward in the direction followed by the cage 23. Once beyond the end of the channel 47, the rocker 42 pivots clockwise about its axis 32 of rotation, in such a way as to divert the double length cigarette 9 away from the concave surface 46 and onto the convex surface 48 in readiness for transfer to the second suction roller 12 at the outfeed station 10. Advantageously, in the rolling unit 2 described and illustrated, both of the rolling surfaces 21 and 46 are rigid in embodiment and capable of generating an extremely precise rolling action on the assembly 4; also, the angular velocity with which the assemblies 4 rotate about their axes during the rolling operation is dependent not on the peripheral velocity of the conveying medium afforded by the cage 23, but simply on the difference between the velocities of the two surfaces 21 and 46. Even in the context of an ultra high speed filter-tipping machine 1, accordingly, the unit 2 disclosed can be operated at relatively low rolling speeds unlikely to inflict any damage whatever on the finished double length cigarettes 9. It will be evident that changeover operations are made extremely simple in the rolling unit 2 according to the invention, given the ease with which the equipment can be set up to operated with assemblies 4 comprising cigarette rods 5 and filters 6 of different diameters. In effect, it is sufficient to remove the drum 20 and fit another of different diameter in order to obtain a rolling channel 47 of the appropriate depth.

Claims: A rolling method for filter tipping machines (1), by which to wrap a band (7) of gummed material around a central portion of an assembly (4) comprising, in addition to the band (7), two lengths of cigarette rod (5) and a double length filter (6) interposed between the two rods (5), in such a way as to obtain a double length filter tipped cigarette (9), including the steps of advancing the assembly (4) continuously by means of a conveyor (23) along a predetermined path at a first predetermined velocity, between an infeed station (3) at which the assembly (4) is taken up and an outfeed station (10) at which the double length cigarette (9) is released, and causing the assembly to roll against the relative band (7) in contact with a rolling element (20) affording a rolling surface (21) that extends along a rolling leg (8) of the path and combines with the conveyor (23) to establish a rolling channel (47), said rolling element (20) being a rigid element set in motion along the conveying path in the same direction as the assembly (4) and at a second velocity other than zero and different to the first velocity; each assembly (4) being made by the conveyor (23) to describe a substantially concave trajectory at least within the compass of the rolling leg (8), which appears as an arc, whilst the rolling surface (21) appears as a convex inner surface having a radius of curvature shorter than that of the concave trajectory; said rolling channel (47) being created between an inner rolling surface (21) of cylindrical geometry and a cylindrical outer surface (46) characterized in that said surfaces being coaxial, both surfaces revolving in the same direction about the same axis (15, 24), the inner surface (21) at a velocity greater than that of the outer surface (46). A method as in claim 1, wherein the inner surface (21) and outer surface (46) are disposed eccentrically one in relation co the other, creating a channel (47) with an entry section and an exit section of transverse dimensions substantially equal to a diameter of the assembly (4) and an intermediate section of transverse dimensions marginally less than this same diameter; A method as in claim 1 or 2, wherein the outer surface (46) is a transport surface presented by the conveyor (23) and consisting in a succession of substantially flat faces (43), each affording a seat (49) to admit a relative assembly (4) and incorporated laterally into a rocker (42) rotatable alternately between a first position, assumed along the rolling channel (47), in which the flat face (43) is directed toward the inner rolling surface (21), and a second position assumed when passing through the infeed and out feed, stations (3, 10) in which the flat face (43) is directed away from the rolling surface (21). A rolling device for filter tipping machines (1), by means of which to wrap a band (7) of gummed paper around a central portion of a cigarette assembly (4) comprising, in addition to the band (7), two lengths of cigarette rod (5) and a double length filter (6) interposed between the two rods (5), in such a way as to obtain a double length filter tipped cigarette (9), comprising a conveyor (23) by which the assembly (4) is advanced continuously along a predetermined path at a first predetermined velocity, between an infeed station (3) at which the assembly (4) is taken up and an outfeed station (10) at which the double length cigarette (9) is released, and a rolling element (20) affording a rolling surface (21) that extends along a rolling leg (8) of the path and combines with the conveyor (23) to establish a rolling channel (47) in which the assembly (4) is rolled against the relative band (7), said rolling element (20) being a rigid element set in motion by relative drive means (17, 16, 14, 53) along the conveying path in the same direction as the assembly (4), at a second velocity other than zero and different to the first velocity; each assembly (4) being made by the conveyor (23) to describe a substantially concave trajectory at least within the compass of the rolling leg (8), which appears as an arc, whilst the rolling surface (21) appears as a convex inner surface having a radius of curvature shorter than that of the concave trajectory; said rolling channel (47) being created between an inner rolling surface (21) of cylindrical geometry and a cylindrical outer surface (46), characterized in that said surfaces being coaxial, both surfaces caused by the drive means (17, 16, 14, 53) to revolve in the same direction about the same axis (15. 24), the inner surface (21) at a velocity greater than that of the outer surface (46). A device as in claim 4, wherein the inner surface (21) and outer surface (46) are disposed eccentrically one in relation to the other, creating a channel (47) with an entry section and an exit section of which the transverse dimensions become progressively narrower toward an intermediate section of the channel (47); A device as in claim 4 or 5, wherein the outer surface (46) is a transport surface presented by a conveyor (23) that comprises a plurality of rockers (42), each presenting a substantially flat lateral face (43), and actuator means (33) by which each rocker (42) is made to rotate alternately between a first position assumed along the rolling channel (47), in which the flat face (43) is directed toward the inner rolling surface (21), and a second position assumed at the infeed and outfeed stations (3, 10) in which the flat face (43) is directed away from the rolling surface (21), and in such a way that the flat faces (43) advancing along the rolling channel (47) and occupying the first position will align one with another co define the outer surface (46), whilst the flat faces (43) lying between the infeed and outfeed stations (3, 10) and occupying the second position will align one with another to establish a further surface (48) lying externally of and substantially concentric with the outer surface (46). A device as in claim 4, wherein the conveyor (23) comprises a hollow cylindrical cage and the rolling element (20) consists in a drum (20) accommodated internally of the cage (23) A device as in claim 7, wherein the drum (20) is coupled to the cage (23) in rotatable and axially slidable association. A device as in claim 7 or 8, wherein the drum (20) is rotatable about a first axis (15), furnished with an outer cylindrical service (21) that functions as the rolling surface (21), and coupled to the drive means (17, 16, 14, 53) in such a way as to rotate about the first axis (15) in a predetermined direction and at a first predetermined angular velocity, whilst the hollow cylindrical cage (23) is rotatable about a second axis (24) parallel to the first axis (15), positioned eccentrically in relation to the drum (20) and coupled to the drive means (17, 16, 14, 53) in such a way as to rotate about the second axis (24) in the same direction as the drum (20) and at a second angular velocity less than the first velocity. A device as in claim 9, wherein the hollow cage (23) comprises: a first annular body (25) and a second annular body (26) disposed coaxial with one another and with the second axis (24); a plurality of shafts (29) extending between and coupled to the first and second annular bodies (25, 26), and rotatable thus in relation to the two annular bodies about respective third axes (32) uniformly distributed about the second axis (24); a plurality of rockers (42) keyed one to each shaft (29), each of which presents a flat lateral face (43) affording a longitudinal seat (49) designed to accommodate a respective assembly (4); and actuator means (33) coupled to each shaft (29), such as will cause the shaft (29) to rotate alternately about the relative third axis (32) between a first position in which the flat face (43) is directed into the cage (23) and toward the rolling surface (21) and a second position in which the flat face (43) is directed away from the cage. A device as in claim 10 wherein each flat face (43) combines when occupying the first position and united with at least one adjacent flat face (43) to establish a substantially cylindrical concave surface (46) centred on the second axis (24), and when occupying the second position and united with at least one adjacent flat face (43) to establish a substantially cylindrical convex surface (48) centred on the second axis (24) and tangential to the infeed and outfeed stations (3, 10). A device as in claim 11, wherein the longitudinal side edges of each rocker (42) exhibit sets of teeth (44, 45) designed to interlock with the teeth (45, 44) of adjacent rockers (42) and thus render the concave and convex surfaces (46, 48) substantially continuous.

Inventors: DRAGHETTI FIORENZO, GHERARDI GIAN LUIGI, DRAGHETTI, FIORENZO, GHERARDI, GIAN LUIGI
Applicants: GD SPA, G.D SOCIETA' PER AZIONI
Application year: 1997
Main classification: A24C5
IPC codes: A24C5