WO2000054611A1

WO2000054611A1 - Trimming device

Info

Publication number: WO2000054611A1
Application number: PCT/AU2000/000187
Authority: WO
Inventors: Mike Brudar; Andrew Trofimiuk; Jason Gorander; Ron Wallace; James Mitchell; Stuart Hingley
Original assignee: Philip Morris Ltd
Current assignee: Philip Morris Ltd
Priority date: 1999-03-12
Filing date: 2000-03-13
Publication date: 2000-09-21
Anticipated expiration: 2001-09-12
Also published as: AUPP917699A0

Abstract

A trimming device (20) is disclosed for trimming a cigarette filler stream in a cigarette making machine. The trimming device (20) has two cooperating disc assemblies (40, 42) arranged to rotate at equal speeds in opposite directions about laterally spaced axes. The disc assemblies (40, 42) make contact at an overlapping zone to trim the filler stream in a scissor like action. The uppermost disc (40) has a plurality of circumferentially cut-outs in its periphery which register during rotation of the disc assemblies (40, 42) with cooperating pockets in one of the discs (66) of disc assembly (42) so as to allow additional quantities of tobacco to sequentially project through a respective aligned cut-out into a respective pocket to trap an additional quantity of tobacco in the pocket at predetermined positions alone the cigarette filler stream. Disc assembly (40) has a knife disc (54) and disc assembly (42) has a knife disc (72).

Description

TRIMMING DEVICE

This invention relates to a trimmer device for trimming a cigarette filler stream in a cigarette making machine. Cigarette making machines operate by forming a tobacco carpet suspended from a perforated suction band by vacuum. The tobacco comes from a chimney located in a suction chamber of the machine. The tobacco carpet travels towards a trimming arrangement, either to leave additional quantities of tobacco on the suction band (pocket discs arrangement) or to compress tobacco respectively and periodically increase the tobacco rod density (compression cam device) to form the cigarette end zones at regular intervals corresponding to the positions of the cigarette ends. These "dense ending" additions of tobacco help to ensure that the open ends of the finished cigarettes cut from the continuous rod formed by the trimmed tobacco carpet which has been enclosed in a continuous bobbin paper are reasonably firm. The cigarettes formed will not excessively be prone to tobacco falling out during further cigarette handling and agitating process through a packing machine. Examples of dense ending devices incorporating the pocket discs arrangement are shown in US Patent Nos. 4,210, 1 59; 4,485,826; 4,276,891 and 3,089,497. Examples of trimming and forming dense end devices incorporating the compression cam device are shown in US Patent Nos. 5,501 ,233; 5,003,996; 5,586,565 and Australian Patent Application No. 60649/94.

The pocket trimming discs arrangement described in US Patent Nos. 4,210, 159; 4,485,826; 4,276,891 and 3,089,497 contain two discs set in a common plane and have their peripheries in close proximity so as to separate retained tobacco (above the discs) from tobacco which is removed with the aid of a rotary sweeping brush. This arrangement has some certain pocket/disc size limitations, mostly in terms of pocket number and its depth/length determined by the associated rotary brush sweeping away excess tobacco obliquely in relation to the direction of movement of the filler stream, so that filler stream returns to the tobacco carpet by a vacuum post-trimming device. This limitation is mostly observed whilst low-density cigarettes are made and greater dense end at the open end of cigarette is desired in relation to remaining part of the cigarette rod. The rotating brush arrangement also damages the tobacco shreds and has the tendency to pull out long strands of tobacco from above the discs leading to variations in final cigarette characteristics.

In the compression cam arrangement as described in US Patent Nos. 5,003,996; 5,586,565 and 5,501 ,233 and Australian Patent Application No. 60649/94 a rotating cam is used to periodically compress additional quantities of tobacco to form dense ends. The concept of the compression cam is based on the difference in linear velocities in the direction of the tobacco carpet flow and cam, prior to the cam reaching its vertical position. This difference in linear velocities creates a tobacco build-up in front of the cam, which is then forced upwards, compressing the tobacco carpet to create the dense end. However, as the velocity of the cam in the direction of the tobacco carpet flow is varying through its rotation it creates a disruption to tobacco flow which not only creates the dense end but also forms voids in the tobacco carpet. The extent of these voids will depend on tobacco carpet height, composition of blend, filling power of tobacco and homogeneity of blend. The situation dramatically deteriorates as the filling power of the tobacco increases to facilitate the production of low-density cigarettes.

It is an object of the present invention to provide a trimmer device that will increase the uniformity of cigarette physical characteristics primarily to facilitate the reduction of rejects due to dense end fall out, tipping faults and under-filled cigarette rods, through the improvement of tobacco carpet trimming and dense end formation.

A further object of the invention is to simplify the trimming assembly arrangement and reduce degradation of the trimmed off tobacco through the elimination of ancillary devices such as the cam, brush arrangements and scrapers of the prior art.

A still further object of the invention is to provide a trimming device that can be readily incorporated into existing cigarette making machines.

With these and other objects in view the present invention provides a trimming device for trimming in a scissor action a cigarette filler stream in a cigarette making machine, said trimming device including two cooperating disc assemblies arranged to rotate at equal speeds in opposite directions about laterally spaced axes, said disc assemblies making contact at an overlapping zone to trim the filler stream in a scissor like action at a first trimming level, the uppermost disc of one of said disc assemblies having a plurality of circumferentially cut-outs in its periphery which register during rotation of the disc assemblies with cooperating pockets in one of said discs of the other of said disc assemblies so as to allow additional quantities of tobacco to sequentially project through a respective aligned cut-out into a respective pocket to trap an additional quantity of tobacco in the pocket at predetermined positions along the cigarette filler stream, said other of said disc assemblies having a knife disc which cooperates with a projection on said one of said disc assemblies to trim off tobacco which does not fit within said respective pocket at a second trimming level. Preferably said one of said disc assemblies includes a knife disc which cooperates with said one of said discs of the other of said disc assemblies to trim said tobacco filler stream to the first trimming level when a respective pocket has been filled with said additional quantity of tobacco. It is preferred that projection on said one of said disc assemblies has sufficient depth and angle to deflect surplus tobacco beneath said disc assemblies away from said disc assemblies.

In a practical embodiment said trimming device further includes a controllable, variable speed drive for said disc assemblies in order that cigarette rods can be made at any length by controlling disc speed to accelerate/decelerate so as to ensure that each dense end portion is formed at a predetermined length from the previous formed portion. Preferably said projection aids the filling of the respective pocket by deflecting tobacco along its radial edge and then engages with said other knife disc forming a scissor action to trim off excess tobacco below the dense end portion thus trapping the additional portion in the pocket such that the projection protrudes into the respective pocket and applies slight lateral compression to the dense end in order to facilitate transition out of said pocket. In order that the invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings, in which:-

Fig. 1 is a side view of a prior art cigarette making machine; Fig. 2 is a plan view of a first embodiment of a trimming device made in accordance with the invention; Fig. 3 is a cross-sectional view along and in the direction of arrows 3-3 of Fig.2;

Figs. 4a, 4b and 4c are similar views to that of Fig. 2 showing the sequential rotation of the discs of the trimming device shown in Fig. 2;

Fig. 5 is graphical representation of the average tobacco filling density distribution of a single dense end in double cigarettes formed by the trimming device shown in Fig. 2;

Fig. 6 is a similar view to that of Fig. 2 showing a second embodiment of a trimming device made in accordance with the invention;

Fig. 7 is graphical representation of the average tobacco filling density distribution of a double dense end in cigarettes formed by the trimming device shown in Fig. 6; Fig. 8 is a similar view to that of Fig. 2 showing a third embodiment of a trimming device made in accordance with the invention; and

Fig. 9 is graphical representation of the average tobacco filling density distribution of a double dense end in cigarettes formed by the trimming device shown in Fig. 8;

In the drawings Fig. 1 shows schematically a typical cigarette making machinel O which creates a tobacco carpet 12 from tobacco coming from making machine chimney 14. The tobacco carpet 12 is suspended underneath a perforated suction band 16 by vacuum supplied from a suction chamber 18. Tobacco carpet 1 2 travels towards trimming device 20 where a consistent mass of tobacco passes above trimming discs (not shown) to maintain physical characteristics of cigarettes as uniform as practically possible. In addition to controlling cigarette weight the trimming device 20 is also commonly used to either leave additional quantities of tobacco on the suction band (pocket discs arrangement) or to compress tobacco respectively and periodically increasing the tobacco rod density (compression cam device) to form cigarette end zones at regular intervals corresponding to the positions of the cigarette ends. These "dense ending" additions of tobacco help to ensure that the open ends of the finished cigarettes cut from the continuous rod formed by the trimmed tobacco carpet and enclosed in a continuous bobbin paper are reasonably firm and are not excessively prone to the tobacco falling out during further cigarette handling and the agitating process through the tipping and packing machine.

After formation of the tobacco carpet with increased density zones at the cigarette rod ends, the vacuum is removed at the left suction belt pulley 22, where the tobacco meets cigarette paper 24 travelling at a similar speed driven by garniture band 26. The paper 24 goes through a cylindrical folding section (not shown) towards a seam adhesive applicator 28 and rod heater 30 to form a continuous cigarette rod. The rod then passes through nuclear density sensing device 32 and is then cut by cut-off mechanism 34 into equal lengths. The machine so far described forms part of the prior art and is commercially available from G.D. S.p.A, Korber AG or Molins Pic.

The present invention relates to an improved trimming device 20 to replace the trimming devices presently fitted to cigarette making machines. Turning to Figs. 2 and 3 the trimming device 20 has a trimming disc arrangement comprising a top disc assembly 40 and bottom disc assembly 42, supported on shafts 44,46 respectively, rotating in opposite directions, as indicated by arrows 48,50 (Fig. 2). The direction of motion of both disc assemblies 40,42 correspond with that of the tobacco carpet central line with equal linear velocity indicated by arrow 52 as the tobacco at this point. Top disc assembly 40 consists of a knife disc 54 having circumferentially opening cut outs 56,58 corresponding to dense end positions fixedly mounted to a top disc carrier 60. In this embodiment cut outs 56,58 are of the same circumferential length and profile/shape although this may be changed. Projections 62 of a suitable depth of top disc carrier 60 are matched beneath open sections of knife disc 54 and are fitted with tungsten carbide tips. Knife disc 54 has a chamfer 64 to assist in the cutting action of the disc and preferably has a recess underneath to minimise friction caused by an engagement of the associated bottom disc assembly 42.

Bottom disc assembly 42 consists of pocket disc 66 having pocket sections 68,70 with the same symmetry as circumferentially opening cut outs 56,58 of knife disc 54, above lower knife disc 72. It is preferred that knife disc 54 and pocket disc 66 be made of tungsten carbide to enhance and assist the cutting action. Both pocket disc 66 and lower knife disc 72 are fixedly mounted to bottom disc carrier 74. The two disc assemblies 40,42 form the trimming disc arrangement which cooperates at the entry end 76 with the lateral rails 78 on either side of perforated suction band 16 of the cigarette making machine. Rails 78 guide tobacco towards and through trimming device 20. The tobacco carpet 12 travelling between lateral rails 78 will be trimmed off at the required carpet height by scissor action obtained from sharp contact between knife disc 54 and pocket disc 66. At the exit end 80 a mouthpiece 82 guides tobacco out of the pocket sections 68,70 for further processing. Surplus tobacco 84 beneath the discs is deflected for re-use by action of the steep and thick edge of pocket disc 66 which has to change direction of surplus tobacco beneath knife disc 54 away from lateral rails 78 and the post trimming area. This will eliminate the need for ancillary devices for tobacco removal such as the rotary brush or scraper of the prior art. In this embodiment both top and bottom disc assemblies

40,42 are supported by means of a casting (not shown) having underneath either screw or belt conveyors (not shown) to remove trimmed off surplus tobacco and returning it back to the making machine hopper (not shown). In order to vary the amount of tobacco in accordance with cigarette weight or density, tobacco carpet 1 2 suspended underneath suction band 1 6 can be displaced vertically by means of a weight control device 86 acting on suction band 1 6. The weight control device 86 continuously maintains cigarette rod weight by means of servo-drive motor 88 or other arrangement. The weight control device 86 will move up and down from a neutral position from suction band 16 and thus control the tobacco carpet 1 2 to be presented to the sharp edges of scissor action top and bottom disc assemblies 40,42 and cut outs 56,58 and pocket sections 68,70. The operation of the trimming device 20 will be described with reference to Figs. 4a, 4b and 4c which are diagrammatic representations of the three major stages through the cycle of producing a single dense end in double cigarettes. Fig. 4a shows the entry phase for dense end formation when tobacco carpet 1 2 is not trimmed by knife disc 54 and pocket disc 66 but instead enters into the open sections 56 and 68 of knife disc 54 and pocket disc 66. Further, the projection 62 aids the filling of the pocket section 68 by deflecting tobacco along its radial edge and then engaging with the lower knife disc 72 to form a scissor action. The scissor action will trim off excess tobacco below the dense end portion thus trapping the additional portion in the pocket section 68 as shown in Fig . 4b. The projection 62 protruding into pocket section 68 will apply slight lateral compression to the dense end in order to facilitate transition out of the pocket into exit mouthpiece 82. Further, the size and length of the dense end portion can be controlled by the depth and length, respectively, of the pocket sections 68 of pocket disc 66 and length of open section 56. Fig. 4c shows the exit stage as the dense end is released into exit mouthpiece 82 which acts as a channel with a wider mouth width at the upstream end, than the tobacco carpet 1 2 and then converging back to the standard rail width downstream, thus capturing the dense end exiting the open section 56 of knife disc 54 and pocket section 68 of pocket disc 66 with minimal disturbance to product flow. Fig . 5 is a graphical representation showing an average tobacco filling density distribution resulting in a single dense end in double cigarettes described in Figs. 4a, 4b and 4c. The height H 1 corresponds to the depth of tobacco cut by the scissors action of knife disc 54 and pocket disc 66 whereas height H2 corresponds to the scissors action of lower knife disc 72 and pocket disc 66. Thus two trimming levels will be achieved .

As previously mentioned in this invention ancillary devices for tobacco removal such as the rotary brush or scraper are not required, thus it is possible to obtain differing dense end amounts along the tobacco carpet corresponding to the open and tipping ends of the cigarette rod. Examples of possible arrangements are shown in Figs. 6 and 7, where, in Fig. 6, the engaging open section 56 of knife disc 54 and pocket section 68 of pocket disc 66 varies in length to open sections 58 and pocket sections 70, maintaining the same dense end trimming level but shortening the length of tipping dense end

Fig . 8 shows an example where the tipping dense end has been reduced in height but not length, by the use of metal inserts 90 to raise the trimming level beneath the dense end . Examples of tobacco carpet profiles for these two scenarios are given in Figs. 6 and 9, respectively Further, a combination of height and length adjustments will allow a reduction of tipping dense end amounts leading to tobacco cost savings and enhancing control over cigarette smoking characteristics and rod firmness.

By having trimming device 20 driven by an independent drive unit, such as a servo drive motor or similar means, it is possible to make a cigarette rod of any length by controlling the disc speed such that as open section 56 and pocket section 68 engage, the linear velocity of discs at the central line is equal to linear velocity of tobacco carpet 1 2 and once the open and pocket sections 56,68 disengage, the discs are accelerated/decelerated so as to ensure that the next dense end portion is formed at the specified length from the previous portion. This eliminates the need to use various disc diameters and gearing assemblies for different rod lengths.

The invention will be understood to embrace many further modifications as will be readily apparent to persons skilled in the art and which will be deemed to reside within the broad scope and ambit of the invention, there having been set forth herein only the broad nature of the invention and a certain specific embodiment by way of example

Claims

1 . A trimming device for trimming in a scissor action a cigarette filler stream in a cigarette making machine, said trimming device including two cooperating disc assemblies arranged to rotate at equal speeds in opposite directions about laterally spaced axes, said disc assemblies making contact at an overlapping zone to trim the filler stream in a scissor like action at a first trimming level, the uppermost disc of one of said disc assemblies having a plurality of circumferentially cut-outs in its periphery which register during rotation of the disc assemblies with cooperating pockets in one of said discs of the other of said disc assemblies so as to allow additional quantities of tobacco to sequentially project through a respective aligned cut-out into a respective pocket to trap an additional quantity of tobacco in the pocket at predetermined positions along the cigarette filler stream, said other of said disc assemblies having a knife disc which cooperates with a projection on said one of said disc assemblies to trim off tobacco which does not fit within said respective pocket at a second trimming level.

2. The trimming device of claim 1 , wherein said one of said disc assemblies includes a knife disc which cooperates with said one of said discs of the other of said disc assemblies to trim said tobacco filler stream to the first trimming level when a respective pocket has been filled with said additional quantity of tobacco.

3. The trimming device of claim 1 or 2, wherein said projection on said one of said disc assemblies has sufficient depth and angle to deflect surplus tobacco beneath said disc assemblies away from said disc assemblies.

4. The trimming device of any one of the preceding claims, further including a controllable, variable speed drive for said disc assemblies in order that cigarette rods can be made at any length by controlling disc speed to accelerate/decelerate so as to ensure that each dense end portion is formed at a predetermined length from the previous formed portion.

5. The trimming device of any one of the preceding claims wherein said projection aids the filling of the respective pocket by deflecting tobacco along its radial edge and then engages with said other knife disc forming a scissor action to trim off excess tobacco below the dense end portion thus trapping the additional portion in the pocket such that the projection protrudes into the respective pocket and applies slight lateral compression to the dense end in order to facilitate transition out of said pocket.

6. The trimming device of any one of the preceding claims wherein the cutting surfaces are made of a tungsten carbide material.

7. The trimming device of any one of the preceding claims, wherein the number, depth, length and width of said pockets can be varied to produce dense end portions of desirable quantities and positions along the cigarette filler stream.

8. The trimming device of any one of the preceding claims, wherein surplus tobacco is returned to said cigarette making machine for recycling .

9. Apparatus for trimming in a scissor action a tobacco filler stream in a cigarette making machine, said apparatus including two disc assemblies of equal diameter contacting each other in an overlapping section, said disc assemblies being set in a common plane and arranged to rotate in opposite directions at equal speeds on parallel shafts to create a scissor action for trimming of said tobacco filler stream at a first trim level, said apparatus also producing dense ends of varying densities along the length of a tobacco rod formed by said tobacco filler stream by having recessed sections in the form of an open section on the top disc and pocket sections on the bottom disc with co-operating projections beneath said open section of said top disc to guide and protrude the tobacco filler stream into respective pocket sections and then trimming the bottom of the additional tobacco portion at a second trim level by action of shearing against a lower knife disc to trap the additional quantity of tobacco in a respective pocket section at pre-defined positions along said cigarette rod.