EP0743020A1

EP0743020A1 - A method and a unit for the formation of a continuous cigarette rod in a cigarette manufacturing machine

Info

Publication number: EP0743020A1
Application number: EP96830285A
Authority: EP
Inventors: Fiorenzo Draghetti; Fausto Mengoli
Original assignee: GD SpA
Current assignee: GD SpA
Priority date: 1995-05-18
Filing date: 1996-05-17
Publication date: 1996-11-20
Also published as: ITBO950235A0; ITBO950235A1; AU5231196A; IT1278206B1

Abstract

A unit (1) for the formation of a continuous cigarette rod (2) in a cigarette manufacturing machine operates by feeding a continuous filler (12) of loose tobacco particles (11) in a given direction (13) and along a predetermined path (14) toward the entry point (15a) of the forming station (15) at which the rod (2) is fashioned; the filler (12) passes initially through a gauging station (28) at which the tobacco mass is trimmed down so as to generate portions (29, 30) of dissimilar thickness alternated at regular intervals, and thereafter through a station (31) preceding the entry point (15a) of the forming station (15), where at least the portions (30) of greater thickness are suitably compacted.

Description

The present invention relates to a method of forming a continuous cigarette rod in a cigarette manufacturing machine.
A typical continuous rod type cigarette manufacturing machine generally comprises a substantially vertical pipe, of which the bottom end takes in a continuous stream of loose tobacco particles, and an aspirating conveyor belt positioned at the top end of the pipe, on which a continuous tobacco filler is formed.
The aspirating belt establishes a predetermined path along which the continuous tobacco filler is directed toward a continuous cigarette rod forming station; at the entry point of this same station, the filler is transferred to a looped conveyor slidably supporting a web of cigarette paper.
The web of paper is forced by the looped conveyor to wrap around the tobacco filler and thus bring about the formation of a continuous cylinder or cigarette rod which is then divided into discrete cigarettes by a cutter device with a rotating blade.
At a given point along the aforementioned path, the tobacco filler generally passes through a gauging station and is subjected to the action of a relative gauging device such as will trim the material down to two different thicknesses alternating regularly one with another.
As the tobacco filler becomes enveloped in the web of cigarette paper, accordingly, the portions of greater thickness produce sections in which the tobacco of the continuous cigarette rod is more densely compacted.
To the end of obtaining single cigarettes with compact ends and minimizing the loss of tobacco from the ends during successive steps of the manufacturing process, the cutter device is timed with the gauging device in such a way that the rotating blade will always engage the rod at an intermediate point along a more densely compacted section.
It has been observed in conventional manufacturing machines that the particles of tobacco making up the portions of different thickness tend to shift during the operation by which the filler is transferred from the aspirating conveyor belt to the web of cigarette paper, with the result that the mass of tobacco is redistributed and the portions of greater thickness no longer advance correctly timed with the action of the rotating blade.
This unwanted effect is attributable to the reaction force induced by a stationary pressure element located at the entry point of the forming station, above the looped conveyor, of which the function is to guide and compress the tobacco filler when deposited on the web of paper and thus favour the subsequent formation of the continuous cigarette rod.
The object of the present invention is to provide a method for the formation of a cigarette rod, in which there is no hint of the drawback described above.
The object thus stated is realized according to the present invention in a method for the formation of a continuous cigarette rod in a cigarette manufacturing machine, comprising the step of feeding a continuous filler of tobacco particles toward the entry point of a continuous cigarette rod forming station in a given direction and along a predetermined path that extends through a gauging station where the filler is trimmed down into portions of different thickness alternated at regular intervals one with another, characterized in that it comprises the further step of compacting the filler, at least along the portions of greater thickness, effected at a compacting station located following the gauging station and preceding the entry point of the continuous cigarette rod forming station in the feed direction.
The compacting step is implemented preferably by compressing the filler.
Similarly, it is an object of the invention to provide a unit for the formation of a continuous cigarette rod in a cigarette manufacturing machine.
The object in question is realized according to the present invention in a unit for the formation of a continuous cigarette rod in a cigarette manufacturing machine, comprising a conveyor by which a continuous filler of tobacco particles is fed toward the entry point of a continuous cigarette rod forming station, moving in a given direction and along a predetermined path that extends through a gauging station, also a gauging device positioned at the gauging station, by which the filler is trimmed down into portions of different thickness alternated at regular intervals one with another, characterized in that it comprises means by which to compact the tobacco filler, at least along the portions of greater thickness, positioned at a relative compacting station located following the gauging station and preceding the entry point of the continuous cigarette rod forming station in the feed direction.
The compacting means preferably will comprise means of compressing the filler.
The invention will now be described in detail, by way of example, with the aid of the accompanying drawings, in which:

fig 1 is the schematic front elevation of a unit for the formation of a continuous cigarette rod according to the present invention, illustrated in a preferred embodiment, partly in section and with certain parts omitted for clarity;
fig 2 is a side elevation illustrating a detail of fig 1;
fig 3 is a front elevation illustrating a further possible embodiment of the detail shown in fig 2. With reference to fig 1 of the accompanying drawings, 1 denotes a unit for the formation of a continuous cigarette rod 2, constituting part of a cigarette manufacturing machine.

The unit 1 comprises an aspirating conveyor belt 3 looped around end rollers 4 (of which one only appears in fig 1), rotatable about respective horizontal and mutually parallel axes 5 in a clockwise direction as viewed in the drawing. The looped belt 3 encompasses a chamber 6 connected by way of a duct 7 with a source of negative pressure (not illustrated) and delimited at the bottom by a wall 8 affording suction holes 9.
As discernible from fig 1, the bottom branch 10 of the belt 3 is disposed in sliding contact with the wall 8 and able by means of suction to retain particles 11 of tobacco issuing from a vertical pipe (not illustrated) located beneath the branch 10, in such a manner as to form a continuous tobacco filler 12. The filler 12 is directed continuously by the branch 10 of the belt in a substantially horizontal direction 13, transversely to the axes 5 of the rollers, along a predetermined path 14 that extends through a station 15 where the continuous rod 2 is formed; coinciding with the entry point 15a of this same station is a looped conveyor 16 of which one portion, denoted 17, extends beneath the belt 3 at a point of convergence with the aspirating branch 10.
Still observing fig 1, the conveyor 16 comprises end rollers 18 of which one (the only one illustrated in fig 1) is disposed substantially beneath the roller 4 of the aspirating belt and rotatable anticlockwise, as viewed in the drawing, about an axis 19 parallel to the axis 5 of the roller 4 above.
The top branch 20 of the conveyor 16 advances slidably on a bed 21, slidably supporting a web 22 of cigarette paper decoiled from a roll 23 and positioned in such a way that the tobacco filler 12 can be transferred from the belt 3 and fed along a set path 24 to a device 24 by which the web 22 is wrapped around the filler 12 to form the continuous rod 2. In particular, the path 24 extends below a fixed guide element 26 positioned at the entry point 15a of the forming station 15.
Again in fig 1, the unit 1 also comprises a gauging device 27 of conventional embodiment, operating at a gauging station 28 located along the aforementioned feed path 14, by which the particles of the filler 12 are trimmed using a familiar technique in such a way as to generate standard portions of a given height and thickness, denoted 29, alternated at regular intervals with shorter portions of greater thickness denoted 30.
According to the present invention, the unit 1 further comprises a compacting station 31 located along the feed path 14 between the gauging station 28 and the entry point 15a of the forming station, at which the tobacco filler 12 is subjected to a firming action; the station 31 is equipped with compacting means 32 comprising a pressure roller 32a, keyed to a shaft 33 rotatable about an axis 34 disposed parallel with the axis 5 of the roller 4 of the aspirating belt 3, and designed to compress the filler 12 against the bottom branch 10 of the belt.
As illustrated in fig 2, the roller 32a is delimited externally by a cylindrical surface 35 divided axially into two equal parts by an annular groove 36 delimited externally in its turn by a concave surface 37.
The cylindrical surface 35 engages in contact with the bottom branch 10 of the belt 3 so that the roller 32a is caused to turn on its axis 34 by friction, rotating anticlockwise (as viewed in fig 1) at a peripheral velocity Vp equivalent to the linear velocity Vc at which the belt 3 advances in the feed direction 13.
Observing the embodiment of the roller 32 indicated in fig 3, the concave surface 37 presents two diametrally opposed projections 38 timed to operate in conjunction with the gauging device 27, and in such a way that the compacting action applied to the filler 12 is more accentuated on the portions 30 of greater thickness than on the remaining portions 29.
In operation, the filler 12 is advanced by the belt 3 along the feed path 14 and directed thus through the gauging station 28, where the filler 12 is trimmed down in such a way as to generate portions 29 and 30 of different thickness, thence into the compacting station 31.
Passing through the latter station 31, the filler 12 is forced to advance within the groove 36 afforded by the roller 32a, with the result that the portions 29 and 30 of both thicknesses are compressed between the concave surface 37 and the branch 10 of the belt 3.
Once beyond the compacting station 31, consequently, the tobacco filler 12 presents a substantially uniform thickness of closely packed tobacco particles 11, with areas corresponding to the portions denoted 30 that remain stable when the filler 12 is transferred to the top branch 20 of the conveyor 16 and directed into the device 25 by which it is enveloped in the web 22 of paper to form the continuous cigarette rod 2.

Claims

A method of forming a continuous cigarette rod (2) in a cigarette manufacturing machine, comprising the step of feeding a continuous filler (12) of tobacco particles (11) toward the entry point (15a) of a continuous cigarette rod forming station (15) in a given direction (13) and along a predetermined path (14) that extends through a gauging station (28) where the filler (12) is trimmed down into portions (29, 30) of different thickness alternated at regular intervals one with another,
characterized
in that it comprises the further step of compacting the filler (12), at least along the portions (30) of greater thickness, effected at a compacting station (31) located following the gauging station (28) and preceding the entry point (15a) of the continuous cigarette rod forming station (15) in the feed direction (13).
A method as in claim 1, wherein the compacting step is effected by compressing the filler (12).
A unit for the formation of a continuous cigarette rod (2) in a cigarette manufacturing machine, comprising a conveyor (3) by which a continuous filler (12) of tobacco particles (11) is fed toward the entry point (15a) of a continuous cigarette rod forming station (15), advancing in a given direction (13) and along a predetermined path (14) that extends through a gauging station (28), also a gauging device (27), positioned at the gauging station (28), by which the filler (12) is trimmed down into portions (29, 30) of different thickness alternated at regular intervals one with another,
characterized
- in that it comprises means (32) by which to compact the tobacco filler (12), at least along the portions (30) of greater thickness, positioned at a relative compacting station (31) located following the gauging station (28) and preceding the entry point (15a) of the continuous cigarette rod forming station (15) in the feed direction.
A unit as in claim 3, wherein compacting means (32) comprise means (32a) by which to compress the tobacco filler (12).
A unit as in claim 4, wherein compression means (32a) comprise a pressure roller (32a) rotatable about a horizontal axis (34) disposed transversely to the feed direction (13).
A unit as in claim 5, wherein the roller (32a) is delimited externally by a cylindrical surface (35) disposed in contact with a conveyor (3) in such a way that the roller (32a) is caused by friction to rotate at a peripheral velocity Vp equivalent to the linear velocity Vc at which the conveyor (3) advances in the feed direction (13).
A unit as in claim 5 or 6, wherein the cylindrical surface (35) is divided axially into two equal parts by an annular groove (36) delimited externally by a concave surface (37).
A unit as in claim 5 or 6, wherein the cylindrical surface (35) is divided axially into two equal parts by an annular groove (36) delimited externally by a concave surface (37) exhibiting two diametrally opposed projections (38).