MACHINE FOR MANUFACTURING FILTER-TIP CIGARETTES

Abstract: This invention relates to the machines for manufacturing filter-tip cigarettes by forming successive groups (S+2F+S) each formed by two aligned cigarettes (S) and one interposed double filter (2F), and by wrapping and glueing a covering strip (T) around the double filter (2F) and adjacent ends of the two cigarettes (S). The formation of the groups (S+2F+S) is carried out on a composition drum (1) whereon the double filters (2F) and the pairs of cigarettes (S) are held by suction. The application of the strip (T) may be carried out either on said composition drum (1) or on a successive assembling drum (6), and the strips are fed by means of a strip-carrying drum (7) whereon they are held by suction. According to the invention, in case of absence of a component, e.g. a double filter (2F), in a group (S+2F+S), all the other components of the same group, i.e. the two cigarettes (S) and covering strip (T), are discarded automatically by affecting for this purpose only the suction exerted on the components to be discarded.

Description: This invention relates to the machines for manufacturing filter-tip cigarettes, wherein successive groups each comprising two aligned cigarettes with an interposed double-length filter are formed on a rotatable composition drum, each of said two cigarettes and filter being held on the composition drum by suction exerted through slits or drawholes provided peripherally in said drum and connectible, through ducts formed in said drum, and over a pre-established angle of rotation thereof, to a vacuum source, while on said composition drum or on a successive rotatable assembling drum, to which the groups comprising the two cigarettes and interposed double filter are transferred, around said filter and adjacent ends of the two cigarettes of each group, there will be wrapped and glued a fastening band, so-called covering strip, which is fed by means of a rotating strip-carrying drum whereon the successive covering strips are each held by suction exerted through one or more corresponding peripheral holes in said strip-carrying drum. In the machines of this type, when a double-length filter is not deposited for any reason between two aligned cigarettes on the composition drum, the covering strip fed subsequently to these two cigarettes will be wrapped and glued with difficulty around their facing ends, so that it may become detached and foul with glue the operating members of the machine, with resulting jamming, stopping and even damaging. The invention aims to overcome these disadvantages by automatically causing - in case of absence of the double-length filter between two aligned cigarettes of a group on the assembling drum - all the components of the respective incomplete group to be discarded, i.e. by causing the two cigarettes to be removed from the assembling drum and by avoiding the transfer of the corresponding covering strip from the strip-carrying drum to either the assembling drum or the connection drum, all the above with no need of sensors and no purposely-provided displacement or removal devices of the two cigarettes of the incomplete group. According to the invention, in order to discard the two cigarettes of a group in case of absence of the interposed double filter, the drawmouths associated with the two cigarettes of each group and/or at least a portion of the ducts connecting these drawmouths to the vacuum source, are in communication with the drawmouth associated with the corresponding interposed double filter, so that, when the double filter is present between the two cigarettes of a group and thus closes the respective drawmouth, the suction exerted through the drawmouth associated with the two cigarettes of the group is sufficient to hold these cigarettes on the composition drum, whereas when said filter is absent and, therefore, the respective drawmouth is open, the communication of this drawmouth with the drawmouths associated with the two cigarettes of the group or with at least a section of the respective ducts connected to the vacuum source, causes such a reduction of the suction through the drawmouths associated with the cigarettes, whereby said cigarettes cannot be held further on the composition drum. To prevent a covering strip from being applied to the composition drum or to the assembling drum onto a void space, i.e. a space lacking a group comprising two aligned cigarettes and an interposed double filter, according to the invention each strip on the strip-carrying drum is provided with glue on the outer side thereof and is detached and picked up from the strip-carrying drum by the engagement and adhesion between the front end (referred to the direction of rotation of the strip-carrying drum) of a strip and the associated group existing on the composition drum or assembling drum, while in the region where said strip is detached and picked up the invention provides means to cause such a partial reduction of the suction exerted through the drawhole (S) associated with said front end of the strip, whereby the force of the residual suction is less than said adhesion force of the strip to a group comprising two cigarettes and one interposed double filter, thus permitting said strip to be detached from the strip-carrying drum and picked up by engagement and adhesion by said group when the latter is present on the composition drum or on the assembling drum, whereas when said group is absent the associated strip is retained by said residual suction with its front end on the strip-carrying drum and moves further thereon past the pick-up region, to be then removed. These and other characteristics of the invention and the advantages resulting therefrom will be apparent with more details in the following description of an embodiment thereof, shown by way of non-limiting example in the accompanying drawings, wherein: Fig. 1 shows quite diagrammatically, an elevational and partly sectional view of a portion of a machine for manufacturing filter-tip cigarettes; Fig. 2 is a longitudinal sectional view of the drum for the composition of the groups each made up by two aligned cigarettes and one interposed double-length filter, on the line II-II of Fig. 1; Fig. 3 is a fragmentary longitudinal sectional view of said composition drum, on the line III-III of Fig. 1; Fig. 4 diagrammatically shows the layout of the peripheral suction groove in the vacuum distributor associated with the composition drum according to Figs. 1 to 3; Fig. 5 diagrammatically shows an elevational and partly sectional view of a portion of the strip-carrying drum and associated assembling drum; Fig. 6 is a fragmentary longitudinal sectional view of the strip-carrying drum according to the line VI-VI of Fig. 5. Fig. 1 shows a fragmentary diagram of a machine for manufacturing filter-tip cigarettes. The numeral 1 indicates a recessed drum, so-called composition drum. A group made up of two aligned cigarettes S and one double-length filter 2F interposed between said two cigarettes S is formed in each peripheral recess of said drum 1. The two cigarettes S of each group S+2F+S are held on the composition drum 1 by suction exerted through corresponding slits or drawmouths 2 provided in the bottom of the recesses 101 and each extending over a certain intermediate portion of the length of the respective cigarette S. Similarly, the double filter 2F of each group is also held on the composition drum 1 by means of a corresponding slit or drawmouth 3 provided in the bottom of the recesses 101 and extending over a certain intermediate portion of the length of said double filter 2F. The double-length filters 2F are transferred after each other from the feeding drum 4 to the composition drum 1 at the zone A, while the two cigarettes S are laid down onto the composition drum 1 at both sides of the filters F by the feeding drum 5 at the zone B, which follows the zone A in the direction of rotation of the composition drum 1 and spaced angularly with respect thereto, e.g. through 90°. At a successive zone D, which is spaced, for example, through 180° with respect to the cigarette-feeding zone B, the individual groups S+2F+S each comprising the two cigarettes S and one interposed double filter 2F, are transferred to a further drum 6, so-called assembling drum, whereon a fastening band T, so-called covering strip, previously coated with glue, is wrapped around the double filter 2F of each group S+2F+S and around the adjacent ends of the two cigarettes S. By means of said covering strip T, the two cigarettes S of each group S+2F+S are connected to the interposed double filter 2F. Thereafter, each group S+2F+S is severed into two filter-tip cigarettes by cutting through intermediately the double filter 2F. As to the construction, the composition drum 1 comprises a hollow cylinder which is rotatably and sealingly mounted on a cylindrical vacuum-distributor 8 overhangingly secured by means of bolts 9 to a supporting wall 10. Opposite the free end of the distributor 8, the composition drum 1 is provided with an end wall 11 by means of which it is secured to a co-axial shaft 12 which is supported by means of bearings 13, 14 in an axial through-bore 108 in the vacuum-distributor 8 and is rotated by means of a toothed wheel 15. At the composition drum 1, the vacuum-distributor 8 is formed with a peripheral suction groove which is generally indicated at 16 and extends circumferentially from a spot just upstream of the zone A where the double filters 2F are transferred from the feeding drum 4 to the composition drum 1, to a spot just upstream of the zone D where the groups S+2F+S are transferred from the composition drum 1 to the assembling drum 6. Said peripheral suction groove 16 in the vacuum-distributor 8 communicates with a vacuum source (not shown) by means of one or more longitudinal ducts 17, angularly spaced from each other (see Fig. 1) and an annular chamber 18, which are formed within the body of the distributor 8, and by means of a tubing 19. The drawmouths 2 provided in each recess 101 of the composition drum 1 in registry with the cigarettes S, are each in communication with two radial suction holes 22, 21 which are spaced apart in the longitudinal direction of the respective recess 101 and open into the interior cylindrical surface of the composition drum 1. The inner radial suction holes 21, which are associated with each of the two drawmouths 2 of a recess 101 of the composition drum 1 are in communication each through a slanting duct 24 with the intermediate drawmouth 3 of the respective recess 101, associated with the double filter 2F which is interposed between the two cigarettes S. The two slanting ducts 24 open into corresponding depressions 124 of the drawmouth 3. The drawmouth 3 associated with the double filter 2F, moreover, communicates with a radial intermediate suction hole 23 which opens into the interior cylindrical surface of the composition drum 1. The cross sectional area of this radial intermediate suction hole (23) is comparatively large with respect to that of the slanting ducts 24. The width of the peripheral suction groove 16 of the vacuum-distributor 8 changes, for example, steppingly along the circumference of said distributor, as viewed clearly in the layout shown in Fig. 4. More particularly, at the zone A, where the double filters 2F are transferred from the feeding drum 4 to the composition drum 1, the suction groove 16 has such a width as to permit the communication therewith - therefore, with the vacuum source - of only the radial hole 23 associated with the drawmouth 3 for the double filter 2F, and the inner holes 21 of the two pairs of radial suction holes 21, 22 associated with the drawmouths 2 for the cigarettes S, as viewed in the upper portion of Fig. 2. As a result, a greater flowrate of sucked air occurs through the drawmouth 3 associated with the double filter 2F, due to the comparatively small section of the slanting holes 24 communicating, at one side, with said drawmouth 3 and, at the other side, with the atmosphere through the inner holes 21 of the still uncovered drawmouths 2 associated with the two cigarettes S. As a result, the double filters 2F picked up from the feeding drum 4 will be held firmly on the composition drum 1. In the zone B where the cigarettes S are transferred from the feeding drum 5 to the composition drum 1, the peripheral suction groove 16 of the vacuum-distributor 8 has such a widening 116 whereby also the outer radial suction holes 22 of the two drawmouths 2 associated with the cigarettes S will communicate with said groove 16, 116 and, therefore, with the vacuum source. Therefore, the cigarettes S transferred from the feeding drum 5 to the composition drum 1 will be firmly held by suction on said composition drum 1, even if the double filter 2F should be absent, that is even if the associated intermediate drawmouth 3 of the respective recess 101 should be left uncovered and, therefore, in communication with the atmosphere. At an intermediate zone C, situated between the two zones B and D on the lower side of the composition drum 1, the peripheral suction groove 16 of the vacuum-distributor 8 comprises a portion 216 which extends over a small arc and is abruptly and considerably narrowed so that only the radial suction hole 23 of the intermediate drawmouth 3 associated with the double filter 2F is left in communication with this narrow portion 216 of said suction groove 16, while all the radial suction holes 21, 22 of the two lateral drawmouths 2 associated with the cigarettes S will be closed, as shown in the lower portion of Fig. 2. In these conditions, when a double filter 2F is present in a recess 101 of the composition drum 1 and covers the respective drawmouth 3, the suction exerted in this drawmouth 3 through the respective radial suction hole 23 will be exerted, through the slanting connecting holes 24, at least partially also in the two lateral drawmouths 2 associated with the two cigarettes S, with a force which is sufficient to hold these cigarettes S in the respective recess 101 of the composition drum 1 over the small angle of rotation of said drum that corresponds to the narrow portion 216 of the suction groove 16. Past the end of said narrow portion 216 of the peripheral suction groove 16 of the vacuum-distributor 8, said groove has a further widening so as to communicate also with at least the inner radial suction holes 21 of the two lateral drawmouths 2 associated with the cigarettes S, whereby the suction is also exerted directly in these lateral drawmouths 2 and the cigarettes S will be firmly held on the composition drum 1. However, when at the zone C the double filter 2F between the two cigarettes S is absent in a recess 101 of the composition drum 1, the intermediate drawmouth 3 is left uncovered, i.e. in communication with the atmosphere, and the suction exerted through the respective radial hole 23 cannot propagate through the slanting connection holes 24 further to the lateral drawmouths 2, or it will be exerted in these lateral drawmouths 2 only with such a reduced force whereby the cigarettes cannot be held on the composition drum 1 against the action of their weight and centrifugal force and, therefore, they fall from said drum into suitable collecting means (not shown). The recess 101 of said drum 1, where the double filter 2F is absent, therefore, is left completely empty downstream of the zone C. The peripheral groove 16 provided in the vacuum-distributor 8 and communicating with the vacuum source terminates at a short distance from the zone D whereat the groups S+2F+S are transferred from the composition drum 1 to the assembling drum 6. Over a small arc at said transfer zone D, the distributor 8 is formed with a peripheral recess 25, so-called vacuum-breaker recess, extending over the entire width of the composition drum 1 and communicating with the atmosphere. By means of this peripheral recess, all the radial suction holes 21, 22, 23 of the drawmouths 2, 3 of each recess 101 in the composition drum 1 are communicated with the atmosphere and thus release the groups S+2F+S each made up by two cigarettes S with an interposed double filter 2F. With reference to Figs. 5 and 6, the covering strips T are fed to the assembling drum 6 by means of a strip-carrying drum 7 which carries a series of angularly equally-spaced strips T provided with glue on the outer face thereof. Each strip T is held on the strip-carrying drum 7 by means of three successive rows of radial suction holes 31, 131; 32 and 33. Each row of suction holes 31, 131; 32 and 33 extends along the axial direction of the drum 7 and comprises a plurality of radial suction holes distributed along the width of the strip T and designed to communicate with a vacuum source through a vacuum-distributor, associated with the strip-carrying drum 7. As to its construction, and as shown in Figs. 5 and 6, the strip-carrying drum 7, is formed of a hollow cylinder which is secured by means of its end wall 107 to the end of a shaft 34 which is rotatably supported in the stationary frame 35 and overhangingly protrudes therefrom. The head surface of the strip-carrying drum 7, directed towards the frame 35, sealingly engages against a vacuum-distributing ring or sector 28 which is secured to the frame 35. Formed in the surface of said ring 28 is an arcuate suction groove 29 communicating with a vacuum source (not shown) through conduits 36, 37 formed in the vacuum-distributing ring 28 and frame 35. Just before the most approached position of the strip-carrying drum 7 and assembling drum 6, the radial width of the arcuate groove 29 is reduced by a step towards the center of the drum 7, so that the arcuate suction groove 29 has a narrower arcuate extension 129 which is radially offset inwards. At the most approached position of the two drums 6 and 7, in the surface of the vacuum-distributing ring 28 there is provided - radially outwards of the narrower extension 129 of the arcuate suction groove 29 - a so-called vacuum-breaker recess 38 communicating with the atmosphere and extending circumferentially over a small arc. A further vacuum-breaker recess 39 of this type is provided in the vacuum-distributing ring 28 downstream of the end of the narrower extension 129 of the arcuate suction groove 29, with respect to the direction of rotation of the strip-carrying drum 7. The first row of suction holes 31, 131 associated with each strip T is designed to hold on the strip-carrying drum 7 the front end of the respective strip 7 (with respect to the direction of rotation of said drum). This row of suction holes comprises a certain member of radial deeper holes 31 and, therebetween, slanting less deep holes 131. The radial suction deeper holes 31 open into a manifold duct 41 extending parallel to the axis of the strip-carrying drum 7 and opening into the head surface thereof, facing towards the vacuum-distributing ring 28, at a radial position corresponding to the arcuate narrow extension 129 of the suction groove 29 of said ring 28. The slanting less deep suction holes 131 open into a manifold duct 141 also extending parallel to the axis of the strip-carrying drum 7 but opening into the head surface thereof, facing towards the vacuum-distributing ring 28, at a radial position corresponding to the radially outer portion of the suction arcuate groove 29, i.e. radially outwards of the narrow extension 129 of said groove 29, and in registry with the vacuum-breaking recess 38. The radial suction holes 32, 33 of the other two rows of holes, which are associated with each strip T on the strip-carrying drum 7, open into corresponding manifold ducts 42 and 43 extending parallel to the axis of said drum 7 and opening into the head surface of the strip-carrying drum 7, facing towards the vacuum-distributing ring 28, at radial positions substantially corresponding to that of said manifold duct 141. Before reaching the zone where it is applied to a group S+2F+S, on the assembling drum 6 each strip T is held firmly on the peripheral surface of the strip-carrying drum 7 by the action of the suction exerted through all the suction holes 31, 131, 32 and 33 because all the respective manifold ducts 41, 141, 42 and 43 communicate with the suction groove 29 in the vacuum-distributing ring 28 and, therefore, with the vacuum source (see right-hand portion of Fig. 5). When the front end of a covering strip T is at the spot where the two drums 6 and 7 are most proximate to each other, it engages a group S+2F+S present on the assembling drum 6 and comprising two cigarettes S and one interposed double filter 2F, and becomes glued to this group, as illustrated in the central portion of Fig. 5. At the same time, the manifold duct 141 for the slanting suction holes 131 associated with the front end of the strip T, is communicated to the atmosphere through the vacuum-breaking recess 38 of the vacuum-distributing ring 28, whereby any suction will no longer be exerted through the slanting holes 131. The front end of the strip T, therefore, is held on the strip-carrying drum 7 only by the action of the suction exerted through the suction holes 31 that still communicate with the vacuum source through the manifold duct 41 and associated extension 129 of the arcuate suction groove 29, as shown in Fig. 6. The residual suction exerted through these holes 31, however, is smaller than the adhesion force of the front end of the strip T to the group S+2F+S on the assembling drum 6. Therefore, the front end of the strip T is detached from the strip-carrying drum 7 and dragged away by the group S+2F+S on the assembling drum 6, against the action of the reduced suction exerted only through the holes 31. Due to the rotation of the strip-carrying drum 7, also the manifold ducts 42, 43 of the successive rows of suction holes 32, 33 will pass over the vacuum-breaking recess 38 in the vacuum-distributing ring 28, whereby the suction through said holes 32, 33 will also be eliminated and the strip T is progressively released and, finally, detached completely from the strip-carrying drum 7, and its front end remains glued to the group S+2F+S on the assembling drum, as shown in the left-hand portion of Fig. 5. Whenever the front end of a covering strip T being fed by the strip-carrying drum 7 does not meet a group S+2F+S on the assembling drum 6, for example, because the two cigarettes S of said group have been discarded previously, as described above, at the composition drum 1 due to the absence of the respective double filter 2F, no detachment and pick-up force will be exerted on said front end of the strip T and said end will be retained further on the strip-carrying drum 7 by the action of the residual suction exerted through the holes 31, the manifold duct 41 of which continues communicating with the narrow extension 129 of the arcuate suction groove 29. As a result, the strip T will be moved by the strip-carrying drum 7 past the spot most approached to the assembling drum 6 and is retained on the strip-carrying drum 7 by the action of the suction exerted through the holes 31 even when the suction through the holes 32, 33 ceases. Past the end of the narrow extension 129 of the arcuate suction groove 29, the manifold duct 41 starts communicating with the vacuum-breaking recess 39, whereby the suction holes 31 are communicated with the atmosphere and release also the front end of the strip T which, therefore, becomes detached automatically from the strip-carrying drum 7 by the action of either gravity or centrifugal force, and falls into suitable collecting means (not shown). The advantages achieved by the invention will be apparent from the above. These advantages, mainly, consist of the fact that in case of absence of a double filter 2F intended for the formation of a group of two cigarettes S with one interposed double filter 2F, both the respective cigarettes S and covering strip T for said group S+2F+S will be discarded, so as to avoid completely any risk of contaminating the machine with cigarettes having no interposed double filter, which could possibly avoid being discarded due to defective glueing of the respective covering strip T or the presence of any lump of glue. A further advantage of the invention consists of the fact that said operative reliability is achieved in a completely automatic manner without using any sensors or movable members other that those which are utilized usually in this type of machines for the manufacture of filter-tip cigarettes, therefore with considerable constructional simplicity. Of course, the invention is not limited to the embodiment just described and shown, but broad changes and modifications, especially of constructional nature, may be made thereto. Moreover, the device according to the invention for eliminating the two cigarettes S of a group S+2F+S in case of absence of the respective interposed double filter 2F, may also be used independently and in combination with any other device for avoiding the application of the respective covering strip T. Similarly, the device according to the invention for avoiding the application of a covering strip in case of absence of the respective group comprising two cigarettes S and interposed double filter 2F, may also be used independently and in combination with any other device for eliminating two cigarettes S of a group S+2F+S when the respective double filter 2F is absent. The principle of the invention for eliminating the two cigarettes S of a group S+2F+S when the respective double filter 2F is absent may also used for eliminating the double 2F in case of absence of the respective two cigarettes S. The invention may also be used advantageously in any other technological field involving similar problems, for example, in the manufacture of composite filter rods, i.e. made up of filter segments of different types wrapped entirely in a long fastening and covering band, for discarding automatically all the components of a filter rod in case of absence of one of them.

Claims: 1. A machine for manufacturing filter-tip cigarettes or the like, wherein successive groups (S+2F+S) each comprising two aligned cigarettes (S) having therebetween one double-length filter (SF) are formed on a rotating drum so-called composition drum (1), each of the two cigarettes (S) and the double filter (2F) being held on the composition drum (1) by suction exerted through corresponding slits or drawmouths (2, 3), or the like, provided peripherally in the composition drum (1) and connectible to a vacuum source by means of a vacuum-distributor (8, 16) and conduits (21, 22, 23) provided in said drum (1), while on said composition drum (1) or a successive rotating drum (6), so-called assembling drum, to which the groups (S+2F+S) comprising the two cigarettes (S) and interposed double filter (2F) are transferred, a fastening band (T) so-called covering strip is wrapped and glued around said double filter (2F) and adjacent ends of the two cigarettes (S) of each group, said fastening band (T) being fed by means of a rotating strip-carrying drum (7), whereon the successive covering strips (T) are each held by suction exerted through one or more corresponding holes (31, 131, 32, 33) provided peripherally in said strip-carrying drum (7) and connectible to a vacuum source by means of a vacuum-distributor (28, 36, 29), characterized in that for discarding automatically the two cigarettes (S) of a group (S+2F+S) in case of absence of the interposed double filter (2F), the drawmouths (2) associated with the two cigarettes (S) of each group (S+2F+S) and/or at least a fraction (21) of the conduits (21, 22) connecting said drawmouths (2) to the vacuum-distributor (8, 16) communicate with the drawmouth (3) associated with the corresponding interposed double filter (2F), so that when the double filter (2F) is interposed between the two cigarettes (S) of a group (S+2F+S) and, therefore, closes the respective drawmouth (3), the suction exerted through the drawmouths (2) associated with the two cigarettes (S) of said group is sufficient to hold these cigarettes (S) on the composition drum (1), whereas when a double filter (2F) is absent and, therefore, the respective drawmouth (3) is left open, the suction through the drawmouths (2) associated with the cigarettes (S) is reduced to such an extent as to be unable to hold them on the composition drum (1). 2. A machine according to the preamble of claim 1, characterized in that in order to prevent a covering strip (T) from being applied to either the composition drum (1) or the assembling drum (6) at a spot devoid of a group (S+2F+S) comprising two cigarettes (S) and one interposed double filter (2F), each strip (T) on the strip-carrying drum (7) is provided with glue on the outer face thereof and is detached and picked up from the strip-carrying drum (7) by engagement and adhesion between the front end of the strip (T), referred to the direction of rotation of the strip-carrying drum (7), and the associated group (S+2F+S) on the composition drum (1) or assembling drum (6), while at the zone where said strip is detached and picked up means are provided to effect such a partial reduction of the suction exerted through the suction hole or holes (31, 131) associated with said front end of the strip (T), whereby the residual suction force will be smaller than the adhesion force of the front end of a strip (T) to a group (S+2F+S) and, therefore, permits the strip (T) to be detached from the strip-carrying drum (7) and picked up by engagement and adhesion by said group (S+2F+S) when the latter is present on the composition drum (1) or the assembling drum (6), whereas in case of absence of said group (S+2F+S) the associated strip is held by said residual suction with its front end on the strip-carrying drum (7) and moves further thereon past the pick-up zone, to be then removed. 3. A machine according to claim 1, wherein the vacuum-distributor associated with the composition drum (1) comprises a stationary cylindrical distributor body (8) whereon is sealingly rotatable said composition drum (1) formed by a hollow cylinder, said distributor body (8) being provided peripherally with a suction groove (16) which communicates with the vacuum source and extends circumferentially from a zone (A) where the double filters (2F) are fed to the composition drum (1), through a zone (B) where the two cigarettes (S) are fed to the composition drum (1) at both sides of each double filter (2F), to a zone (D) where the groups (S+2F+S) formed each by two cigarettes (S) and one interposed double filter (2F) are removed from the composition drum (1), while the drawmouths (2, 3) associated with the two cigarettes (S) and double filter (2F) of each group (S+2F+S) communicate with radial suction holes (21, 22, 23) which are provided in the hollow composition drum (1) and which open into the interior cylindrical surface thereof in registry with the peripheral suction groove (16) of the distributor body (8), characterized in that the drawmouth (2) associated with each cigarette (S) communicates with at least two radial suction holes (21, 22) which are spaced apart along the respective drawmouth (2) and one of which - preferably, the inner hole 21 - is connected to the drawmouth (3) which is associated with the double filter (2F) through a conduit (24) formed in the hollow cylindrical body of the composition drum (1). 4. A machine according to claim 3, characterized in that the peripheral suction groove (16) in the distributor body (8) has, at the zone (A) where the double filters (2F) are fed, such a width as to communicate only with a part (21) of the radial suction holes (21, 22) connected to the drawmouths (2) associated with the cigarettes (S), while it has, at the zone (B) where the pairs of cigarettes (S) are fed, such an enlargement (116) as to communicate with all the radial suction holes (21, 23) connected to the drawmouths (2) associated with the cigarettes (S). 5. A machine according to claims 3 and 4, characterized in that downstream of the zone (B) where the pairs of cigarettes (S) are fed, with reference to the direction of rotation of the composition drum (1) and preferably in the lower part of said drum (1), the peripheral suction groove (16) of the distributor body (8) has such a restriction (216) as to communicate there with only the suction hole or holes (23) connected to the drawmouth (3) associated with the double filter (2F). 6. A machine according to claim 2, characterized in that the front end of each strip (T) is held on the strip-carrying drum (7) by means of a plurality of suction holes (31, 131) communicating with two respective manifold ducts (41, 141) which open into a head surface of the strip-carrying drum (7) at two positions which are at different distances from the axis of said drum (7) and in registry with an arcuate suction groove (29) which is co-axial with the strip-carrying drum (7) and is provided in a stationary distributor body (28) which is sealingly engaged by the corresponding head surface of said strip-carrying drum (7), said arcuate suction groove (29) being connected to the vacuum source and being radially narrowed, i.e. restricted, at the zone where the strip (T) is picked up, whereby only a part (31) of the suction holes (31, 131) will be left in communication with the narrowed extension (129) of the suction groove (29), while the remaining part (131) of the suction holes is communicated with the atmosphere by means of a corresponding vacuum-breaking recess (38) provided in the distributor body (28). 7. A machine according to claim 6, characterized in that, in addition to the suction holes (31, 131) associated with the front end of the strip (T), each strip is held on the drum by means of one or more successive suction holes (32, 33) connected to the manifold ducts (42, 43) which open into the head surface of the strip-carrying drum (7) at such a radial distance from its axis of rotation as to communicate with the vacuum-breaking recess (38) provided at the zoned where the strip (T) is picked up. 8. A machine according to claims 6 or 7, characterized in that downstream of the zone where the strip (T) is picked up, with reference of the direction of rotation of the strip-carrying drum (7), the distributor body (28) comprises therein a vacuum-breaking recess (39) connected to the atmosphere and with which the communication will be established by the suction hole or holes (31) which are associated with the front end of a strip (T) and whose manifold duct (41) communicates, at the zone where the strip (T) is picked up, with the narrow extension (129) of the arcuate suction groove (29).

Inventors: GHERARDI, GIAN LUIGI
Applicants: SASIB S.P.A.
Application year: 1989
Main classification: A24C5
IPC codes: A24C5