Method of producing filter-tipped cigarettes

On a filter assembly machine, a succession of groups, each having two cigarette portions, a double filter between the two cigarette portions, and a gummed strip connected integral with, along a generating line of, and projecting forwards from the group, is fed by an input conveyor to a loading station where each group is transferred into a respective seat on a rolling device with multiple rolling channels; the groups being unloaded off the rolling device with a smaller pitch as compared with the input pitch.

BACKGROUND OF THE INVENTION 
The present invention relates to a method of producing filter-tipped 
cigarettes. 
Filter-tipped cigarettes are normally produced from double cigarettes, each 
formed by rolling a gummed strip of paper material about a group 
consisting of two cigarette portions separated axially by a filter twice 
as long as that of a finished filter-tipped cigarette. 
The strips are normally rolled about said groups by means of a rolling 
device to which the groups are normally fed by an input roller with a 
number of peripheral seats. Each seat receives and retains by suction both 
a respective group, and a respective gummed strip with one end connected 
to the group, along a generating line of the group opposite the seat, and 
projecting rearwards from the group in relation to the rotation direction 
of the input roller. 
U.S. Pat. No. 4,848,371 relates to a so-called "multiple-channel" rolling 
method. 
Here and hereinafter, the term "multiple-channel rolling" is intended to 
mean a rolling method whereby each group is fed to a respective transfer 
conveyor by which it is fed along a respective rolling channel in turn 
traveling along a given path. 
More specifically, as described in U.S. Pat. No. 4,848,371, the input 
roller transfers the groups successively to a central rolling device or 
drum substantially tangent to the input roller at a loading station, and 
rotating, at a first given speed equal, at the loading station, to that of 
the input roller, about an axis parallel to the rotation axis of the input 
roller. The central drum comprises a ring of peripheral transfer rollers, 
each mounted on the drum so as to rotate, in relation to the drum, about a 
respective axis parallel to the rotation axis of the drum, and so as to 
define, with a peripheral portion of the drum, a respective rolling 
channel moving at said first speed along a circular path. Each transfer 
roller presents a respective peripheral seat which, by virtue of the 
central drum and the respective transfer roller rotating about their 
respective axes, travels through the loading station together with and at 
the same speed as a corresponding seat on the input roller, and is 
supplied by the input roller with a respective group and strip, which it 
feeds along said respective rolling channel. At the end of the rolling 
operation, said seat receives the newly formed double cigarette and, in 
the same way as for pickup but in reverse, transfers it to a seat on an 
output roller. 
The advantages of multiple-channel as compared with standard single-channel 
rolling are considerable in that the multiple channels not only provide 
for rendering rolling speed substantially independent of the traveling 
speed of the cigarettes, thus enabling faster production speeds, but also 
prevent total stoppage of the machine in the event of a cigarette being 
damaged inside the rolling channel. 
One drawback of multiple-channel rolling, however, poses problems in the 
case of applications involving production speeds over and above a given 
limit. In fact, as a consequence of the manner, described above, in which 
each group and respective strip on the input roller are presented at the 
loading station, the group is transferred to the seat on the respective 
transfer roller with the strip facing the latter seat and extending 
rearwards in relation to the traveling direction of the central drum. 
Since the strip faces rearwards, winding of the strip about the respective 
group--which is performed by expelling the group from the seat on the 
transfer roller and rolling it on the surface of the transfer roller and 
on the respective strip along the respective rolling channel--can only be 
performed by rolling the group backwards in relation to the respective 
transfer roller, which in turn can only be achieved by rotating the 
transfer rollers in the same direction as the central drum, with the 
result that, at the loading station, the speed of the central drum is 
added to that of the seat on each transfer roller, and the pitch of the 
seats on the input roller is much greater than the already relatively wide 
pitch of the axes of the transfer rollers about the periphery of the 
central drum. 
The relatively wide pitch of the seats on the input roller, and 
consequently also on the output roller, poses serious drawbacks in that, 
on the one hand, at high production speeds, the traveling speeds of the 
cigarettes up- and downstream from the rolling drum are practically 
unsustainable, and, on the other, a relatively drastic and hence 
relatively complex pitch reduction is required along the filter assembly 
machine, prior to feeding the cigarettes to the input conveyor of the 
packing machine. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide a multiple-channel 
rolling method designed to overcome the aforementioned drawbacks. 
According to the present invention, there is provided a method of producing 
filter-tipped cigarettes, the method being characterized by the fact that 
it comprises, in combination, stages consisting in feeding, by means of an 
input conveyor, in a given direction and with a first given pitch , a 
succession of groups, each comprising at least one cigarette portion, a 
filter, and a gummed strip connected integral with and along a generating 
line of the group, and projecting forwards from the group in said given 
direction; successively transferring said groups into respective seats on 
a rolling device of the type presenting multiple rolling channels, the 
rolling device feeding said seats with a second given pitch along a path 
tangent to the input conveyor at a loading station and to an output 
conveyor at an unloading station; rolling said groups into filter-tipped 
cigarettes as they travel between said loading and unloading stations; and 
transferring the filter-tipped cigarettes to the output conveyor by 
adjusting the pitch of the cigarettes so that they are fed along the 
output conveyor with a third pitch differing from the first pitch.

DETAILED DESCRIPTION OF THE INVENTION 
Number 1 in FIG. 1 indicates a filter assembly machine comprising a powered 
rolling unit 2 in turn comprising an input roller 3 rotated by a known 
drive device (not shown) about its axis (not shown) perpendicular to the 
FIG. 1 plane. Unit 2 also comprises a central rolling drum 4 substantially 
tangent to roller 3 at a loading station 5, fitted in rotary manner to a 
fixed central shaft 6, and rotated by a drive device 8 about the axis 7 of 
shaft 6, parallel to the axis (not shown) of roller 3. Finally, unit 2 
comprises an output roller 9 substantially tangent to drum 4 at an 
unloading station 10, and rotated by a known drive device (not shown) 
about its axis (not shown) parallel to axis 7. 
Device 8 rotates drum 4 clockwise (in FIG. 1) about axis 7 at a 
substantially constant given speed, while rollers 3 and 9 are rotated 
anticlockwise (in FIG. 1) about their respective axes (not shown) at 
respective substantially constant speeds by said drive devices (not 
shown). 
As shown in FIG. 1, roller 3 is defined by a perforated tubular body 
supported in rotary and axially-fixed manner on a fixed central pneumatic 
distributor 11, and rotated anticlockwise (in FIG. 1) in relation to 
distributor 11. Roller 3 presents a number of peripheral seats 12 equally 
spaced by distance P1, and each of which receives a respective group 13, 
defined (in known manner not shown) by two cigarette portions (not shown) 
separated by a double filter (not shown), and a respective gummed strip 
14. Strip 14 provides for joining the two cigarette portions of respective 
group 13 to the respective double filter, and is arranged, on roller 3, 
with its rear portion (in the traveling direction of seats 12) gummed to a 
generating line of respective group 13 opposite respective seat 12, and 
with its front portion projecting forwards in relation to group 13 and 
resting on a respective retaining element 15 located on the periphery of 
roller 3 in front of said seat 12 in the rotation direction of roller 3. 
Distributor 11 comprises a suction chamber 16 communicating with a given 
number of seats 12 and elements 15 immediately upstream from station 5; 
and a compressed air supply chamber 17 communicating with at least seat 12 
and respective element 15 immediately downstream from station 5 in the 
rotation direction of roller 9. 
Output roller 9 presents a known internal structure (not shown) similar to 
that of roller 3, and a number of peripheral seats 18 equally spaced by 
distance P2 smaller than P1, for receiving and retaining by suction 
respective double filter-tipped cigarettes 19 fed by drum 4 through 
station 10. 
Drum 4 is supplied by roller 3 with a succession of groups 13 with 
respective strips 14, and provides for connecting said cigarette portions 
and said filter (not shown) in each group 13 by winding respective strip 
14 about the filter and the respective ends of the cigarette portions 
adjacent to the filter to form a double cigarette 19. 
As shown particularly in FIG. 2, drum 4 comprises a substantially circular 
front disk 20 and rear disk 21, fitted idly to shaft 6 and coaxially with 
axis 7 via the interposition of respective bearings 22 and 23. On its 
front surface 24, disk 20 is fitted integral with a disk 25 smaller in 
diameter than disk 20, and the outer lateral surface of which presents a 
succession of radial cavities 26, each with its concavity facing outwards, 
and each defined by a cylindrical surface extending about a respective 
axis 27 parallel to axis 7. On its rear surface 28, rear disk 21 is fitted 
with a sleeve 29 coaxial with axis 7, and the rear end of which presents 
teeth 30 constituting the output element of device 8, which also comprises 
a powered gear 31 meshing with teeth 30 for rotating disk 21 clockwise (in 
FIG. 1) about axis 7. Disk 21 is made angularly integral with disk 20 by a 
connecting device 32 comprising a number of pairs of rods 33 and 34 
parallel to axis 7 and equal in number to cavities 26. More specifically, 
each rod 33 is coaxial with respective axis 27, and is supported in rotary 
and axially-fixed manner by disks 20 and 21 via the interposition of 
bearings 35 and 36; whereas corresponding rod 34 is offset radially 
towards axis 7 in relation to rod 33, and is supported in rotary and 
axially-fixed manner by disks 20 and 21 via the interposition of bearings 
37 and 38 coaxial with each other and with a respective axis 39 parallel 
to axis 27. 
Each rod 33 projects frontwards of surface 24 of disk 20, and is fitted 
with a respective transfer roller 40 rotated anticlockwise (in FIG. 1) 
about respective axis 27 by a drive 41, and presenting two 
diametrically-opposed peripheral suction seats 42 and 43, and a number of 
suction holes 44 behind each seat 42, 43 in the rotation direction of 
roller 40. Together with the inner surface of respective cavity 26, each 
roller 40 defines a curved rolling channel 45 of a width roughly equal to 
but no larger than the diameter of group 13, and presenting a 
roll-initiating tooth 46 at the input. 
As shown in FIG. 2, drive 41 comprises a fixed helical sun gear 47 between 
disks 20 and 21 and fitted to a central portion of shaft 6; and, for each 
roller 40, a helical gear 48 coaxial with respective axis 27, and an idle 
helical gear 49 coaxial with respective axis 39 and interposed between 
gear 47 and respective gear 48. Gear 49 is longer than respective gear 48, 
and much longer than sun gear 47. 
Gears 48 and 49 of each roller 40 are fitted to respective sleeves 50 and 
51 in turn fitted in axially-sliding manner to respective rods 33 and 34 
between disks 20 and 21, and supported for rotation, via the interposition 
of respective bearings 52 and 53, on the opposite arms 54--substantially 
radial in relation to axis 7--of a respective substantially C-shaped frame 
55 comprising an intermediate core 56 parallel to axis 7 and connecting 
the two arms 54. A pin 57 projects radially outwards from core 56 of each 
frame 55, and supports in idle manner a tappet roller 58 engaging a fixed 
drum type cam 59 extending about axis 7 and presenting a level portion 60, 
and a substantially sinusoidal portion 61 extending along an arc AB, 
located upstream from station 5 in the rotation direction of drum 4, and 
comprising station 10. 
Upon tappet roller 58 of each frame 55 engaging portion 61 of cam 59, frame 
55 moves axially along respective rods 33 and 34 so that respective gear 
49 moves axially in relation to sun gear 47; and, due to the helical teeth 
of gears 49 and 47 meshing with each other, said axial displacement, 
depending on its direction, provides for angularly accelerating or 
decelerating gear 49, and for increasing or decreasing the angular speed 
of respective roller 40 about respective axis 27. 
More specifically, as of point A of said arc AB, each roller 40 is 
decelerated to a minimum speed at point C, at which it is accelerated to 
return to its original speed at point D and to a maximum speed, greater 
than the original speed, at point E in station 10. As of this point, the 
angular speed of roller 40 is again decelerated to return to its original 
speed at point F, and to a further minimum speed at point G, from which it 
is restored to its original speed at point B. 
As in the example shown, the angle by which roller 40 is backed up along 
arc AD, as compared with a roller 40 rotating at constant speed V3=V0, is 
preferably recovered along arc DE, which also applies to arcs FB and EF. 
By moving roller 40 as described above, therefore, it is possible for it 
to assume, at points A, E and B, the same angular position as a roller 40 
rotating at constant speed V3=V0 along the whole of arc AB. Portion 61 of 
cam 59 would of course be designed differently for simply increasing speed 
V3 to a maximum at point E. 
Gear 47 and gears 48, 49 are so sized that, as drum 4 rotates about its 
axis 7, each roller 40 makes a finite number (two, in the example shown) 
of full turns about its axis 27 as it travels between station 5 and 
station 10, and turns a further 180.degree. about its axis 27 as it 
travels between station 10 and station 5. 
By virtue of drum 4 rotating about axis 7, and rollers 40 simultaneously 
rotating about respective axes 27 and in relation to roller 3, each group 
13 transported by drum 4 between stations 5 and 10 travels precessionally 
along a substantially circular path S through stations 5 and 10; and, as 
drum 4 rotates, seats 42, 43 engaged by groups 13 travel along path S with 
a variable pitch P3 always greater than pitch P1 and P2. 
Operation of machine 1 will now be described, for the sake of simplicity, 
with reference to one group 13 retained by suction by chamber 16 inside a 
seat 12, having a respective forward-projecting strip 14, and traveling 
towards station 5 at a substantially constant speed V1; and with reference 
to one roller 40 fed by drum 4 towards station 5 at a speed V2 equal to 
speed V1 at station 5, and rotated about its axis 27 by drive 41 at a 
surface speed V3, so that, at station 5, V1=V2-V3. 
Group 13 reaches station 5 simultaneously with a suction seat 42, 43 on 
roller 40, and, by cutting off suction through chamber 16, is drawn by 
suction into seat 42, 43 with respective strip 14 directly contacting seat 
42, 43 and facing forward in the rotation direction of drum 4, but 
rearwards in the rotation direction of roller 40 in relation to drum 4. 
A compressed air jet from chamber 17 is directed through respective element 
15 on to strip 14 immediately downstream from station 5, so that strip 14 
adheres to the outer surface of roller 40 on which it is retained by 
suction through holes 44. 
On receiving group 13 and respective strip 14, roller 40 continues rotating 
anticlockwise so that group 13 engages rolling channel 45 and, on 
contacting tooth 46, is detached from seat 42, 43 and begins rolling 
between the surfaces of roller 40 and cavity 26 and along channel 45 at a 
traveling speed equal to half the surface speed of roller 40. As it does 
so, group 13, in the example shown, makes two full turns about its axis, 
and strip 14, formerly adhering only by its rear edge to group 13, is 
wound about group 13 to connect the cigarette portions and the filter and 
so form a double filter-tipped cigarette 19. On reaching the output of 
channel 45, group 13 engages seat 43, 42 diametrically opposite former 
seat 42, 43. 
At this point, roller 40 continues to be rotated anticlockwise (in FIG. 1) 
by drive 41, and at the same time is fed by drum 4 to station 10 where the 
newly formed double cigarette 19 is transferred in known manner to roller 
9. 
Between stations 5 and 10, the speed V3 of roller 40 is maintained 
substantially constant as respective roller 58 travels along level portion 
60 of cam 59, but is varied upon roller 58 engaging portion 61 of cam 59, 
and reaches a maximum speed, decidedly greater than the speed along 
portion 60 (more specifically, at station 5) as roller 40 travels through 
station 10. 
Positioning strips 14 so as to extend forwards in relation to respective 
groups 13 on roller 3 therefore provides for rotating rollers 40 in the 
opposite direction to drum 4, and so drastically reducing the resulting 
speed of seats 42, 43 through station 5 and seats 43, 42 through station 
10, as compared with the speed V2 imparted by drum 4 to axes 27. As a 
result, the pitch P1 and P2 of seats 12 and 18 is less than pitch P3 of 
groups 13 along path S, thus reducing speed V1 for a given number of 
groups 13 fed per unit of time through station 5. 
Moreover, as speed V3 is maximum at station 10, the ratio between pitches 
P1 and P3 will be the inverse of that of speeds V3 at stations 5 and 10 
respectively. In other words, by appropriately designing portion 61 of cam 
59, the pitch between input roller 3 and output roller 9 of rolling unit 2 
may be reduced as required.