Cigarette packing machine

Abstract

 A cigarette packing machine (1), wherein a packing device (2) has at least one conduit (5; 5, 70) extending through a loading station (11; 11, 68) for loading a respective succession of sheets (4; 4, 69) of packing material, and along which groups (3) of cigarettes are fed in steps in a given travelling direction (7) by a push device (12); and wherein the conduit (5; 5, 70) has folding devices (14, 49, 54, 55, 58, 59, 60; 14, 49, 54, 55, 58, 59, 60, 14', 49', 54', 55') for folding each sheet (4; 4, 69) of packing material about the relative group (3) of cigarettes; and the push device (12) has a number of pushers (31, 32, 36, 37, 38; 31, 32, 36, 37, 38, 32', 36', 37'), each of which is integral with the other pushers, and moves each group (3) of cigarettes forward one respective step in a sequence of steps of each group (3) of cigarettes along the conduit (5; 5, 70).

Description

[0001] The present invention relates to a cigarette packing machine.

[0002] More specifically, the present invention relates to a cigarette packing machine of the type comprising a packing device for packing groups of cigarettes by folding at least one respective inner sheet of packing material about each group of cigarettes, and wherein the packing device comprises at least one first conduit defining a straight first channel, along which a succession of groups of cigarettes travels in a given travelling direction along a packing path; a feed conveyor for feeding flat inner sheets of packing material along a feed path intersecting the packing path and the first conduit at a loading station, and extending crosswise to the travelling direction; folding means located along the first conduit to fold each inner sheet of packing material about the respective group of cigarettes to form an inner wrapping about each group of cigarettes; and push means for feeding the groups of cigarettes along the first channel and through the loading station.

[0003] Folding the inner sheet of packing material about the group of cigarettes has been found to result in possible damage to the tips of the cigarettes (i.e. the tobacco ends opposite the filters) in the form of local deformation and/or tobacco fall-out (i.e. from the tips). Damage caused by folding the inner sheet of packing material about the group of cigarettes applies in particular to the cigarettes at the corners of the group, but is also noticeable in all the outer cigarettes, i.e. located along the fold lines of the inner sheet of packing material.

[0004] Moreover, a new type of impermeable, heat-seal inner sheet of packing material has been proposed, which is sealed at the end corresponding to the tips of the cigarettes, in that, at the filter end, the inner sheet of packing material has a cigarette withdrawal opening closed by a fastening tab with reusable, non-dry adhesive. Folding this type of inner sheet of packing material is particularly harmful to the cigarettes, on account of it being thicker (and therefore stiffer) than conventional foil inner sheets. Moreover, at the fastening tab (where the first end fold is made), the inner sheet of packing material is extremely thick (almost twice the thickness) and therefore extremely rigid locally.

[0005] It is an object of the present invention to provide a cigarette packing machine of the type described above, which is cheap and easy to produce and comprises relatively few component parts.

[0006] According to the present invention, there is provided a cigarette packing machine as claimed in the accompanying Claims.

[0007] A number of non-limiting embodiments of the present invention will be described by way of example with reference to the accompanying drawings, in which:

Figure 1 shows a schematic view in perspective, with parts removed for clarity, of a first embodiment of the packing machine according to the present invention;

Figure 2 shows a view in perspective of a detail of Figure 1;

Figures 3 and 4 show axial sections and respective operating sequences of the Figure 2 detail;

Figures 5 and 6 show a folding sequence performed by the Figure 2 detail;

Figure 7 shows a schematic view in perspective, with parts removed for clarity, of a second embodiment of the packing machine according to the present invention;

Figure 8 shows a view in perspective of a detail of Figure 7;

Figure 9 shows a schematic side view, with parts removed for clarity, of two wheels of a different packing machine;

Figure 10 shows a plan view of a detail of Figure 9.

[0008] Number 1 in Figure 1 indicates as a whole a cigarette packing machine comprising a packing device 2 for packing groups 3 of cigarettes by folding a respective inner sheet 4 of packing material, normally foil, about each group 3 of cigarettes.

[0009] In the example shown, packing device 2 comprises a number of substantially identical superimposed packing conduits 5, each of which defines a respective straight folding channel 6 (Figures 3 and 4) along which a respective succession of groups 3 of cigarettes travels along a respective packing path P1 in a travelling direction 7 parallel to the cigarette axes.

[0010] Packing device 2 also comprises a conveyor 8 for feeding groups 3 of cigarettes to an input station 9 where groups 3 of cigarettes are fed into respective packing conduits 5; a feed conveyor 10 for feeding flat inner sheets 4 of packing material along a feed path P2 extending crosswise to travelling direction 7 and intersecting packing paths P1 and packing conduits 5 at respective loading stations 11; and a push device 12 common to all the packing conduits 5, and which feeds each group of cigarettes 3 along relative packing conduit 5, from relative input station 9 to a relative output station 13, and through relative loading station 11.

[0011] In variations not shown, packing conduits 5 may be side by side, instead of superimposed, and differ in number from the number shown; packing device 2 may even comprise only one packing conduit 5.

[0012] Unless otherwise stated, the following description refers to one packing conduit 5.

[0013] With reference in particular to Figure 2, packing conduit 5 comprises an input portion, defined by a tubular spindle 14, and an output portion 15, which are located on opposite sides of loading station 11 and successively in travelling direction 7, and define folding channel 6. Output portion 15 is fixed, and has a concave input end 16 substantially tangent to feed path P2 and to loading station 11, and defining a seat engaged by a convex output end 17 (Figures 3, 4) of tubular spindle 14, which is moved back and forth in travelling direction 7, by known actuating means not shown, to and from an engaged position (Figure 3c) in which output end 17 of tubular spindle 14 engages input end 16 of output portion 15. Output portion 15 is divided into two fixed portions 18, 19 separated by a folding station 20.

[0014] As shown in Figure 1, push device 12 comprises a frame 21 common to all the packing conduits 5, and in turn comprising a bar 22 parallel to travelling direction 7 and located outside packing conduits 5; two arms 23, 24 extending from respective ends of bar 22 towards packing conduits 5; and two further bars 25, 26, which are integral with the free ends of arms 23, 24, respectively, are perpendicular to respective arms 23, 24, and extend crosswise to travelling direction 7. Push device 12 also comprises, for each packing conduit 5, two aligned rods 27, 28 parallel to travelling direction 7; rod 27 is integral with bar 25 and located at relative tubular spindle 14; and rod 28 is integral with bar 26 and located at relative output portion 15.

[0015] Two brackets 29, 30, bent into an L towards respective output station 13, extend from rod 27 towards relative packing conduit 5, and support respective pushers 31, 32, each defined by a plate, which is integral with respective bracket 29, 30, is positioned crosswise to travelling direction 7, and is shaped and sized to slide inside folding channel 6.

[0016] Three brackets 33, 34, 35, bent into an L towards respective output station 13, extend from rod 28 towards relative packing conduit 5, and support respective pushers 36, 37, 38 identical to pushers 31, 32.

[0017] Frame 21 moves along an annular path P3 (Figure 3a) comprising a first insertion portion crosswise to travelling direction 7, and along which some of pushers 31, 32, 36, 37, 38 are inserted inside folding channel 6 through respective slots 39 formed, crosswise to travelling direction 7, in packing conduit 5; a conveying portion, along which pushers 31, 32, 36, 37, 38 are moved along the inside of folding channel 6 in travelling direction 7, and brackets 29, 30, 33, 34, 35 are moved along a slot 40 formed longitudinally along packing conduit 5; a second withdrawal portion crosswise to travelling direction 7, and along which some of pushers 31, 32, 36, 37, 38 are withdrawn from folding channel 6 through respective slots 39; and a return portion, along which pushers 31, 32, 36, 37, 38 travel outside packing conduit 5.

[0018] As frame 21 moves cyclically along path P3, each group 3 of cigarettes fed to input station 9 of relative packing conduit 5 is engaged successively by pushers 31, 32, 36, 37, 38, each of which moves group 3 of cigarettes forward one respective step in a sequence of steps, all longer than the length of group 3 of cigarettes, by the end of which, group 3 of cigarettes reaches output station 13.

[0019] Operation of packing device 2 will now be described with reference to Figures 3 and 4, to one packing conduit 5, and to one group 3 of cigarettes, and as of the instant (Figure 3a) in which frame 21 is located at the end of the return portion of annular path P3; and the substantially rectangular parallelepiped-shaped group 3 of cigarettes (indicated 3a) is positioned at input station 9 coaxially with folding channel 6, with its cigarettes parallel to travelling direction 7, with its major lateral surfaces 41 positioned vertically, with its minor lateral surfaces 42 positioned horizontally, with one end surface 43 (tobacco end) at the front in travelling direction 7, and with its other end surface 44 (filter end) at the rear. As of this instant, frame 21 performs a first cycle along annular path P3, during which, frame 21 travels along the insertion portion of annular path P3 to position pusher 31 (Figure 3b) a given distance D upstream from and facing end surface 44 of group 3a of cigarettes. Frame 21 then moves along the conveying portion of annular path P3 to first bring pusher 31 (Figure 3c) into contact with end surface 44, and then move group 3a of cigarettes a first step forward (Figure 4a) in travelling direction 7. This first step inserts group 3a inside tubular spindle 14 and stops it in a position (indicated by group 3b in Figure 4a) in which group 3b is positioned with end surface 44 contacting pusher 31 at a distance D downstream from a first slot 39 formed through tubular spindle 14, and with its end surface 43 close to the output end 17 of spindle 14.

[0020] During the rest of the first cycle along annular path P3, frame 21 (Figure 4b) backs up by distance D to align pusher 31 with first slot 39, pusher 31 is withdrawn (Figure 4c) through first slot 39, and pusher 32 is then aligned (Figure 3a) with first slot 39.

[0021] During this first step, group 3a of cigarettes is gripped laterally, by virtue of the portion, indicated 6a, of folding channel 6 defined by spindle 14 tapering towards output end 17.

[0022] At this point, frame 21 performs a second cycle along annular path P3, during which, frame 21 moves along the insertion portion of annular path P3 to insert pusher 32 through first slot 39 and position pusher 32 (Figure 3b) at distance D from end surface 44 of group 3b of cigarettes. During insertion of pusher 32 through first slot 39, spindle 14 is stationary in a withdrawn position (Figure 3b) so as to define, with portion 18 of packing conduit 5 and at loading station 11, a gap through which an inner sheet 4 of packing material is fed and positioned across packing path P1, with its longitudinal axis perpendicular to the Figure 3 plane. When frame 21 is moved along the conveying portion of annular path P3 to move group 3b of cigarettes one step forward in travelling direction 7, spindle 14 is moved in travelling direction 7 so that, before pusher 32 reaches end surface 44 of group 3b of cigarettes, output end 17 of tubular spindle 14 engages input end 16 of portion 18 of packing conduit 5 (Figure 3c) to fold inner sheet 4 of packing material into a U to define (Figure 5b) a first end wall 45 and two opposite major lateral walls 46, 47 of an inner wrapping 48 (Figure 6h). During the rest of this step, end surface 43 of group 3b of cigarettes first contacts end wall 45; group 3b of cigarettes and the relative U-folded inner sheet 4 of packing material are then inserted (Figure 4a) inside portion 18 of packing conduit 5; and, finally, group 3b of cigarettes (indicated 3c) is arrested inside portion 18 of packing conduit 5.

[0023] As shown in Figure 5b, inner sheet 4 of packing material is wider than major lateral surfaces 41 of a group 3 of cigarettes; and major lateral walls 46, 47 are longer by a distance D than major lateral surfaces 41 of group 3 of cigarettes. Seeing as, along portion 18 of packing conduit 5, folding channel 6 has substantially the same section as group 3 of cigarettes, insertion of group 3b of cigarettes inside portion 18 (Figure 5c) forms - by interference with two fixed folding devices 49 at input end 16 of portion 18 - two first portions 50, adjacent to end wall 45, of two opposite minor lateral walls 51 (Figure 6e) of inner wrapping 48, and, for each first portion 50 of a minor lateral wall 51, two longitudinal lateral flaps 52, 53 (Figure 5c), each of which projects outwards from relative first portion 50 of minor lateral wall 51, is coplanar with a respective major lateral wall 46, 47, and engages a respective helical folding device (Figure 2) defined by a respective helical slot 54, 55 formed along portion 18 of packing conduit 5.

[0024] By the end of the above step, group 3c of cigarettes is positioned (Figure 4a) with the rear end of major lateral walls 46, 47 immediately downstream from a second slot 39 formed through portion 18 of packing conduit 5, close to input end 16, and with end surface 44 contacting pusher 32 and at a distance D downstream from second slot 39.

[0025] During the rest of the second cycle along annular path P3, frame 21 backs up (Figure 4b) by distance D to align pusher 32 with second slot 39, pusher 32 (Figure 4c) is withdrawn through second slot 39, and pusher 36 is then aligned with second slot 39.

[0026] During a third cycle along annular path P3, pusher 36 (Figure 3b) is inserted into folding channel 6 through second slot 39, moves along folding channel 6 in travelling direction 7 into contact with end surface 44 of group 3c of cigarettes, and feeds group 3c of cigarettes along helical slots 54, 55 to fold longitudinal lateral flaps 52, 53 squarely and complete the formation of minor lateral walls 51 to form a tubular wrapping 56 (Figure 6e), which contains a relative group of cigarettes, here indicated 3d, is closed at one end by end wall 45, and has, at the opposite end, a tubular appendix 57 projecting from end surface 44 of group 3d of cigarettes.

[0027] During the rest of the third cycle along annular path P3, frame 21 backs up by distance D to align pusher 36 with a third slot 39, pusher 36 is withdrawn through third slot 39, and pusher 37 is then aligned with third slot 39.

[0028] During a fourth cycle along annular path P3, pusher 37 is inserted inside folding channel 6 through third slot 39, moves along folding channel 6 in travelling direction 7 into tubular appendix 57 and into contact (Figure 3c) with end surface 44 of group 3d of cigarettes, and feeds group 3d of cigarettes (Figure 4a) through folding station 20 to insert group 3d of cigarettes and relative tubular wrapping 56 inside portion 19 of packing conduit 5.

[0029] By the end of this step, the group of cigarettes, here indicated 3e, is positioned (Figure 4a) with its end surface 44 coplanar with a folding plane P4 perpendicular to travelling direction 7, and in which operate three folding devices 58, 59, 60 (Figure 2), which move back and forth to and from a position of interference with tubular appendix 57.

[0030] During the rest of the fourth cycle along annular path P3, frame 21 backs up (Figure 4b) by distance D, pusher 37 is withdrawn through folding station 20 and aligned with third slot 39, and pusher 38 is positioned in folding plane P4. In this connection, it should be pointed out that the distance between pushers 37 and 38 exceeds, by an amount equal to D, the distance between any other pair of adjacent pushers.

[0031] During the rest of the fourth cycle, folding devices 58, 59, 60 are operated. More specifically, folding devices 58, 59, positioned opposite, are moved towards each other to engage the minor lateral walls of tubular appendix 57 and form two minor flaps 61, 62 on end surface 44 of group 3e of cigarettes (Figure 6f); and folding device 60, located on the opposite side of packing path P1 with respect to push device 12, is moved towards push device 12 to engage a respective major lateral wall of tubular appendix 57 and form a respective major flap 63 on end surface 44 of group 3e of cigarettes (Figure 6g).

[0032] During a fifth cycle along annular path P3, pusher 38 moves along folding plane P4 into folding station 20, and engages tubular appendix 57 to form (Figure 6h) a further major flap 64 which, together with minor flaps 61, 62 and the other major flap 63, defines an end wall 65 of inner wrapping 48, which is thus completed to define an inner packet 66, which is pushed out of packing conduit 5 as pusher 38 moves in travelling direction 7.

[0033] Pushers 31, 32, 36, 37, 38 obviously all move forward in respective steps simultaneously, so that, for each cycle of frame 21 along annular path P3, a group 3a of cigarettes is fed into spindle 14, and an inner packet 66 is fed out of portion 19 of packing conduit 5.

[0034] To form a rigid outer package (not shown) about inner packet 66, inner packet 66 is fed to a packing unit (not shown) for forming rigid packets.

[0035] Conversely, to form a soft cup-shaped outer package 67 (Figure 7) about inner packet 66, inner packet 66 may be fed, as shown in the Figure 7 and 8 variation, to a further packing conduit 68, which is coaxial with and located downstream from packing conduit 5 in travelling direction 7, and defines a further folding channel 69 extending through a further loading station 70, similar to loading station 11, for loading outer sheets 71 of packing material supplied to loading station 70 by a conveyor 71a similar to conveyor 8.

[0036] In the embodiment shown, packing conduit 68 comprises an axially-moving tubular spindle 14' substantially identical to tubular spindle 14, but not tapered internally; and a fixed portion 18' substantially identical to portion 18 of packing conduit 5. Tubular spindle 14' and fixed portion 18' are located on opposite sides of loading station 70 along packing path P1. And the parts of packing conduit 68 are indicated using the same reference numbers, but with superscripts, as for the corresponding parts of packing conduit 5.

[0037] In packing conduit 68, each inner packet 66 is loaded into relative spindle 14' directly by relative pusher 38, and is fed through loading station 70 and along fixed portion 18' by three further pushers 32', 36', 37' fitted integrally to bar 22 of frame 21 of push device 12 by a further arm 72, a further bar 73, and a further rod 74.

[0038] In a variation not shown, portion 19 of packing conduit 5 is movable axially back and forth in the same way as tubular spindle 14, spindle 14' and pusher 32' are eliminated, and loading station 70 is interposed between portion 19 and portion 18' which, in this case, defines the whole of packing conduit 68.

[0039] Packing conduit 68 is connected to at least one gumming device (typically located along feed conveyor 71a of outer sheets 71 of packing material) for applying spots of glue to each outer sheet 71 of packing material to stabilize respective cup-shaped outer package 67.

[0040] In a further embodiment not shown, the cigarette packing machine in Figures 7 and 8 also forms a transparent, heat-sealed outer overwrapping about each soft cup-shaped outer package 67 by folding a sheet of transparent, heat-seal overwrapping material about cup-shaped outer package 67. In which case, each cup-shaped outer package 67 is fed to a third packing conduit coaxial with packing conduit 5 and further packing conduit 68, located downstream from further packing conduit 68 in travelling direction 7, and defining a third folding channel extending through a third loading station, similar to loading station 11 and loading station 70, for loading sheets of overwrapping material supplied to the third loading station by a third conveyor similar to conveyor 8 and conveyor 71a.

[0041] In the embodiment shown, the third packing conduit comprises an axially-moving tubular spindle substantially identical to tubular spindle 14, but not tapered internally; and a fixed portion substantially identical to portion 18 of packing conduit 5. The tubular spindle and the fixed portion are located on opposite sides of the third loading station along packing path P1.

[0042] In the third packing conduit, each outer package 67 is loaded into the relative spindle directly by relative pusher 37', and is fed through the third loading station and along the fixed portion by three third pushers fitted integrally to bar 22 of frame 21 of push device 12 by a third arm, a third bar, and a third rod.

[0043] The third packing conduit is connected to at least one heat-seal device for heat sealing each sheet of overwrapping material to stabilize the respective outer overwrapping.

[0044] As stated, when frame 21 is moved along the conveying portion of annular path P3 to move group 3b of cigarettes one step forward in travelling direction 7, tubular spindle 14 is moved in travelling direction 7 so that, before pusher 32 reaches end surface 44 of group 3b of cigarettes, output end 17 of tubular spindle 14 engages input end 16 of portion 18 of packing conduit 5 (Figure 3c) to fold inner sheet 4 of packing material into a U to define (Figure 5b) a first end wall 45 and two opposite major lateral walls 46, 47 of an inner wrapping 48 (Figure 6h). Consequently, inner sheet 4 of packing material is initially folded into a U, not by the axial thrust exerted on inner sheet 4 of packing material by the cigarettes in group 3 of cigarettes, but by the thrust exerted by tubular spindle 14, which also acts as a folding device. As a result, when folding inner sheet 4 of packing material into a U, the cigarettes in group 3 of cigarettes are in no way stressed axially, and therefore subject to no deformation or tobacco fall-out from the tips.

[0045] In other words, cigarette packing machine 1 in Figures 1-8 comprises at least one packing conveyor (defined by a respective packing conduit 5 and by push device 12) to receive and feed a group 3 of cigarettes along packing path P1; feed conveyor 10 for feeding a sheet 4 of packing material immediately upstream from input end 16 of the packing conveyor and crosswise to packing path P1, so that, as group 3 of cigarettes enters the packing conveyor, sheet 4 of packing material is folded into a U about group 3 of cigarettes; and a folding device (tubular spindle 14) located at input end 16 of the packing conveyor to fold sheet 4 of packing material into a U inside the packing conveyor just before group 3 of cigarettes is inserted inside the packing conveyor, i.e. before group 3 of cigarettes comes into contact with sheet 4 of packing material.

[0046] In one possible embodiment, tubular spindle 14 has an end wall, which comes into contact with sheet 4 of packing material to fold sheet 4 of packing material into a U, and which has suction means for retaining sheet 4 of packing material. The suction means preferably comprise at least two suction holes on opposite sides of packing path P1, and suction through the suction means is activated when tubular spindle 14 folds sheet 4 of packing material into a U, and is cut off once sheet 4 of packing material is folded into a U.

[0047] As will be clear from the above description, cigarette packing machine 1 comprises actuating means for moving tubular spindle 14 reciprocatingly (i.e. back and forth) along packing path P1.

[0048] Number 72 in Figure 9 indicates as a whole a cigarette packing machine, which comprises a feed wheel 73 rotating about a central axis of rotation 74 and having at least one peripheral pocket 75 for housing group 3 of cigarettes; a packing wheel 76 rotating about a central axis of rotation 77 and having at least one peripheral pocket 78 for housing group 3 of cigarettes wrapped in sheet 4 of packing material; and feed conveyor 10 for feeding a sheet 4 of packing material between wheels 73 and 76. As it is transferred from pocket 75 on feed wheel 73 to pocket 78 on packing wheel 76, group 3 of cigarettes intercepts the sheet 4 of packing material supplied by feed conveyor 10.

[0049] Cigarette packing machine 72 comprises a folding device 79 located between wheels 73 and 76 to fold sheet 4 of packing material into a U before sheet 4 of packing material is contacted by group 3 of cigarettes. Folding device 79 is fork-shaped, and comprises two folding fingers 80 located on opposite sides of packing path P1 and alongside wheels 73 and 76.

[0050] A preferred embodiment shown in Figure 9 comprises a fixed folding edge 81 interposed between wheels 73 and 76 to fold sheet 4 of packing material partly before sheet 4 of packing material is inserted inside pocket 78 on packing wheel 76. More specifically, fixed folding edge 81 is tubular with a central through opening 82 through which sheet 4 of packing material and group 3 of cigarettes are fed.

[0051] The Figure 9 embodiment also comprises a push device 83 for expelling group 3 of cigarettes from pocket 75 on feed wheel 73 into pocket 78 on packing wheel 76, and so intercepting sheet 4 of packing material pre-folded by folding device 79; and a counter-pusher 84, which grips sheet 4 of packing material against an end wall of group 3 of cigarettes to ease sheet 4 of packing material and group 3 of cigarettes into pocket 78 on packing wheel 76.

[0052] In the Figure 9 embodiment, feed conveyor 10 is located along feed wheel 73, upstream from the transfer station to packing wheel 76, and deposits sheet 4 of packing material on the outer surface of feed wheel 73: sheet 4 of packing material is retained mechanically and/or by suction on the outer surface of feed wheel 73.

Claims

1. A cigarette packing machine comprising:

a packing device (2) for packing groups (3) of cigarettes by folding at least one respective inner sheet (4) of packing material about each group (3) of cigarettes; and wherein the packing device (2) comprises at least one first conduit (5) defining a straight first channel (6) along which a succession of groups (3) of cigarettes travel in a given travelling direction (7) along a packing path (P1);

feed means (10) for feeding flat inner sheets (4) of packing material along a feed path (P2) intersecting the packing path (P1) and the first conduit (5) at a loading station (11) and extending crosswise to the travelling direction (7);

folding means (14, 49, 54, 55, 58, 59, 60, 38) located along the first conduit (5) to fold each inner sheet (4) of packing material about the relative group (3) of cigarettes to form a relative inner wrapping (48); and

push means (12) for feeding the groups (3) of cigarettes along the first channel (6) and through the loading station (11);

the packing machine (1) being characterized in that the push means (12) are step-operated push means, and comprise a number of first pushers (31, 32, 36, 37, 38) connected integrally to one another; each first pusher (31; 32; 36; 37; 38) moving each group (3) of cigarettes forward one respective step in a sequence of steps of each group (3) of cigarettes along the first channel (6).

2. A packing machine as claimed in Claim 1, wherein the first conduit (5) comprises a first and a second portion (14, 15) arranged successively in the travelling direction (7) and defining the first channel (6), and of which the second portion (15) is fixed and has a concave input end (16), and the first portion (14) has a convex output end (17); and wherein the feed path (P2) and the loading station (11; 69) are substantially tangent to the input end (16); and the first portion (14) is movable back and forth, in the travelling direction (7), to and from an engaged position, in which the output end (17) and the input end (16) are engaged, to fold each inner sheet (4) of packing material into a U.

3. A packing machine as claimed in Claim 1 or 2, wherein the push means (12) comprise a frame (21) supporting all the first pushers (31, 32, 36, 37, 38), and which is movable along an annular path (P3) comprising a first portion crosswise to the travelling direction (7) and along which the first pushers (31, 32, 36, 37, 38) are inserted inside the first channel (6); a conveying portion, along which the first pushers (31, 32, 36, 37, 38) are moved along the inside of the first channel (6) in the travelling direction (7); a second portion crosswise to the travelling direction (7) and along which the first pushers (31, 32, 36, 37, 38) are withdrawn from the first channel (6); and a return portion, along which the first pushers (31, 32, 36, 37, 38) are moved outside the first conduit (5).

4. A packing machine as claimed in Claim 3, wherein each first pusher (31; 32; 36; 37; 38) comprises a respective bracket (29; 30; 33; 34; 35) positioned crosswise to the travelling direction (7) and connecting the first pusher (31; 32; 36; 37; 38) to the frame (21).

5. A packing machine as claimed in Claim 4, wherein the first conduit (5) has a longitudinal slot (40) for passage of the brackets (29, 30, 33, 34, 35); and a number of transverse slots (39) intersecting the longitudinal slot (40) and for insertion-withdrawal of the first pushers (31, 32, 36, 37, 38).

6. A packing machine as claimed in any one of Claims 1 to 5, wherein each step is longer than the length of the group (3) of cigarettes.

7. A packing machine as claimed in any one of Claims 2 to 6, wherein the sequence of steps comprises an insertion step, in which the group (3) of cigarettes is inserted inside the first portion (14) of the first conduit (5).

8. A packing machine as claimed in any one of Claims 2 to 7, wherein the sequence of steps comprises a transfer step, in which the group (3) of cigarettes and the inner sheet (4) of packing material are transferred into the second portion (15) of the first conduit (5) to form a first end wall (45) and two opposite first lateral walls (46, 47) of the inner wrapping (48); two first portions (50), adjacent to the first end wall (45), of two opposite second lateral walls (51) of the inner wrapping (48); and, for each first portion (50) of a second lateral wall (51), two longitudinal lateral flaps (52, 53), each of which projects outwards from the relative first portion (50) of a second lateral wall (51), and is coplanar with a respective first lateral wall (46; 47).

9. A packing machine as claimed in Claim 8, wherein the folding means (14, 49, 54, 55, 58, 59, 60, 38) comprise first fixed folding devices (49) located at the input end (16) of the second portion (15) of the first conduit (5) to form each first portion (50) of a second lateral wall (51) and each longitudinal lateral flap (52; 53).

10. A packing machine as claimed in Claim 9, wherein the folding means (14, 49, 54, 55, 58, 59, 60, 38) comprise second fixed folding devices (54, 55) located along the second portion (15) of the first conduit (5) to fold the longitudinal lateral flaps (52, 53) squarely onto the relative group (3) of cigarettes and complete formation of the second lateral walls (51) to define a tubular wrapping (56), which contains the group (3) of cigarettes, is closed at a first end by the first end wall (45), and has, at a second end opposite the first end, a tubular appendix (57) projecting from a relative end of the group (3) of cigarettes; the sequence of steps comprising a feed step, in which the group (3) of cigarettes and the inner sheet (4) of packing material are fed along the second portion (15) of the first conduit (5) and engage the second fixed folding devices (54, 55).

11. A packing machine as claimed in Claim 10, wherein the folding means (14, 49, 54, 55, 58, 59, 60, 38) comprise a number of movable folding devices (58, 59, 60, 38) to fold the tubular appendix (57) and form a second end wall (65) of the inner wrapping (48); the movable folding devices (58, 59, 60, 38) being mounted at a folding station (20), located along the second portion (15) of the first conduit (5), to move back and forth through the first channel (6) and crosswise to the travelling direction (7).

12. A packing machine as claimed in Claim 11, wherein the movable folding devices (58, 59, 60, 38) comprise one (38) of the first pushers (31, 32, 36, 37, 38).

13. A packing machine as claimed in any one of Claims 2 to 12, wherein the sequence of steps comprises an expulsion step, in which the group (3) of cigarettes and the inner wrapping (48) are expelled from the second portion (15) of the first conduit (5).

14. A packing machine as claimed in one of Claims 2 to 13, wherein, along the first portion (14) of the first conduit (5), the first channel (6) tapers towards the second portion (15) to grip the group (3) of cigarettes transversely as the group (3) of cigarettes is fed (7) through the first portion (14).

15. A packing machine as claimed in any one of Claims 1 to 14, wherein the packing device (2) comprises:

a second conduit (68), which defines a straight second channel (69) extending through a second loading station (70), is located along the packing path (P1), and is aligned with the first conduit (5) downstream from the first conduit (5) in the travelling direction (7);

conveying means (71a) for feeding flat outer sheets (71) of packing material to the second loading station (70) ;

second folding means (14', 49', 54', 55') located along the second conduit (68) to fold each outer sheet (71) of packing material about the inner wrapping (48) of a relative group (3) of cigarettes to form a cup-shaped outer package (67) about each group (3) of cigarettes; and

second push means (32', 36', 37') for feeding the groups (3) of cigarettes and relative inner wrappings (48) along the second channel (69) and through the second loading station (70).

16. A packing machine as claimed in Claim 15, wherein the second push means (32', 36', 37') are step-operated push means (12), and comprise a number of second pushers (32', 36', 37') connected integrally to one another; each second pusher (32'; 36'; 37') moving each group (3) of cigarettes forward one respective step in a sequence of steps of each group (3) of cigarettes along the second channel (69).

17. A packing machine as claimed in Claim 16, wherein the second pushers (32', 36', 37') are integral with the first pushers (31, 32, 36, 37, 38).

18. A packing machine as claimed in any one of Claims 15 to 17, wherein the second conduit (68) comprises a first (14') and a second (18') portion arranged successively in the travelling direction (7) and defining the second channel (69); and wherein the first and second portion (14', 18') of the second conduit (68) are located on opposite sides of the second loading station (70).

19. A packing machine as claimed in Claim 18, wherein the first and second portion (14', 18') of the second conduit (68) are substantially identical to the first (14) and part (18) of the second (15) portion of the first conduit (5) respectively.

20. A packing machine as claimed in any one of Claims 15 to 19, wherein the second conduit (68) has at least one gumming device for applying spots of glue to each outer sheet (71) of packing material to stabilize the respective cup-shaped outer package (67).

21. A packing machine as claimed in any one of Claims 15 to 20, wherein the packing device (2) comprises:

a third conduit, which defines a straight third channel extending through a third loading station, is located along the packing path (P1), and is aligned with the second conduit downstream from the second conduit in the travelling direction (7);

conveying means for feeding flat sheets of overwrapping material to the third loading station;

third folding means located along the third conduit to fold each sheet of overwrapping material about the cup-shaped outer package (67) of a relative group (3) of cigarettes to form an outer overwrapping; and

third push means for feeding the groups (3) of cigarettes and relative inner wrappings and cup-shaped outer packages (48, 67) along the third channel and through the third loading station.

22. A packing machine as claimed in Claim 21, wherein the third push means are step-operated push means, and comprise a number of third pushers connected integrally to one another; each third pusher moving each cup-shaped outer package (67) forward one respective step in a sequence of steps of each cup-shaped outer package (67) along the third channel.

23. A packing machine as claimed in Claim 22, wherein the third pushers are integral with the second pushers (32', 36', 37').

24. A packing machine as claimed in any one of Claims 21 to 23, wherein the third conduit comprises a first and a second portion arranged successively in the travelling direction (7) and defining the third channel; and wherein the first and second portion of the third conduit are located on opposite sides of the third loading station.

25. A packing machine as claimed in Claim 24, wherein the first and second portion of the third conduit are substantially identical to the first (14) and part (18) of the second (15) portion of the first conduit (5) respectively.

26. A packing machine as claimed in any one of Claims 21 to 25, wherein the third conduit has at least one heat-seal device for heat sealing each sheet of overwrapping material to stabilize the respective outer overwrapping.

27. A cigarette packing machine comprising:

at least one packing conveyor (5, 12; 76) for receiving a group (3) of cigarettes and feeding the group (3) of cigarettes along a packing path (P1); and

feed means (10) for feeding a sheet (4) of packing material immediately upstream from an input end (16) of the packing conveyor (5, 12; 76) and crosswise to the packing path (P1), so that, as the group (3) of cigarettes enters the packing conveyor (5, 12; 76), the sheet (4) of packing material is folded into a U about the group (3) of cigarettes ;

the packing machine (1) being characterized by comprising a folding device (14, 79) located at the input end (16) of the packing conveyor (5, 12; 76) to fold the sheet (4) of packing material into a U before the group (3) of cigarettes contacts the sheet (4) of packing material.

28. A packing machine as claimed in Claim 27, wherein the folding device (14, 79) has an end wall, which comes into contact with the sheet (4) of packing material to fold the sheet (4) of packing material into a U, and which has suction means for retaining the sheet (4) of packing material.

29. A packing machine as claimed in Claim 28, wherein the suction means comprise at least two suction holes on opposite sides of the packing path (P1).

30. A packing machine as claimed in Claim 28 or 29, wherein suction through the suction means is activated when the folding device (14, 79) folds the sheet (4) of packing material into a U, and is cut off once the sheet (4) of packing material is folded into a U.

31. A packing machine as claimed in one of Claims 27 to 30, and comprising actuating means for moving the folding device (14, 79) back and forth along the packing path (P1) .

32. A packing machine as claimed in one of Claims 27 to 31, wherein the folding device (14) is tubular, and the group (3) of cigarettes is fed through the tubular folding device (14) into the packing conveyor (5, 12; 76).

33. A packing machine as claimed in one of Claims 27 to 31, wherein the folding device (79) is fork-shaped, and comprises two folding fingers (80) on opposite sides of the packing path (P1).

34. A packing machine as claimed in one of Claims 27 to 33, and comprising a feed wheel (73), which rotates about a first central axis of rotation (74), comprises at least one peripheral first pocket (75) for housing the group (3) of cigarettes, and feeds the group (3) of cigarettes to the packing conveyor (5, 12; 76).

35. A packing machine as claimed in Claim 34, wherein the packing conveyor (5, 12; 76) is a packing wheel (76), which rotates about a second central axis of rotation (77), and comprises a second pocket (78) for housing the group (3) of cigarettes wrapped in the sheet (4) of packing material.

36. A packing machine as claimed in Claim 35, wherein the folding device (79) is fork-shaped, and comprises two folding fingers (80) located on opposite sides of the packing path (P1) and alongside the feed wheel (73) and the packing wheel (76).

37. A packing machine as claimed in Claim 35 or 36, and comprising at least one fixed folding edge (81) interposed between the feed wheel (73) and the packing wheel (76) to partly fold the sheet (4) of packing material before the sheet (4) of packing material is inserted inside the second pocket (78) of the packing wheel (76).

38. A packing machine as claimed in Claim 37, wherein the fixed folding edge (81) is tubular with a central through opening (82) through which the sheet (4) of packing material and the group (3) of cigarettes are fed.

39. A cigarette packing method comprising the steps of:

feeding a sheet (4) of packing material immediately upstream from an input end (16) of a packing conveyor (5, 12; 76) and crosswise to a packing path (P1); and feeding a group (3) of cigarettes to the packing conveyor (5, 12; 76) so that, as the group (3) of cigarettes enters the packing conveyor (5, 12; 76), the sheet (4) of packing material is folded into a U about the group (3) of cigarettes;

the method being characterized by comprising the further step of:

folding the sheet (4) of packing material into a U by means of a folding device (14, 79), located at the input end (16) of the packing conveyor (5, 12; 76), before the group (3) of cigarettes comes into contact with the sheet (4) of packing material.

Drawing