GB1575910A

GB1575910A - Continuousrod making machines

Info

Publication number: GB1575910A
Application number: GB2490676A
Authority: GB
Original assignee: Molins Ltd
Current assignee: Mpac Group PLC
Priority date: 1977-06-14
Filing date: 1977-06-14
Publication date: 1980-10-01

Description

(54) CONTINUOUS-ROD MAKING MACHINES (71) We, MOLINS LIMITED, a British Company of 2, Evelyn Street, Deptford, London SE8 5DH., do hereby declare this invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: - This invention concerns improvements in or relating to continuous-rod making machines. In particular it concerns the application of adhesive to the paper web which is wrapped around a filler to form a continuous rod. The invention is especially concerned with the application of adhesive to the paper web in a cigarette making machine.

In a conventional continuous-rod cigarette making machine, adhesive (such as polyvinyl acetate (PVA), or starch) is applied to the inside of an upstanding edge of the paper web part way along the rodforming assembly, which is generally termed the garniture, after the other edge has already been folded into position around the tobacco. The upstanding edge is then folded down on top of the other edge so as to form the traditional longitudinal lap seam down the cigarette.

A problem with such a conventional cigarette making machine is that an appreciable time is taken for the adhesive to set sufficiently for the seam to remain closed. Even by accelerating the drying process of the adhesive in the seam by the use of heaters (which can lead to difficulties in the starting and stopping of the machine), the time taken may be excessive at high rod speeds.

In the manufacture of cigarette filter rods it is known to apply adhesive to the edge of the web which will become the outer lap of the longitudinal seam at a position upstream of the garniture, so that the adhesive has already become tacky by the time the two edges are brought together around the filter material.

It has also been proposed in British Patent Specification No. 927,927 to use such a method in cigarette making machines; but since the adhesive is facing the tobacco filler, there is a considerable risk that the tacky adhesive surface will become contaminated with small particles of tobacco and dust before the seam is formed.

This is unsightly, and may result in a leaky and insecure seam. For example tobacco particles may escape from the tobacco filler as it is transferred onto the paper from the filler forming tape, or during passage through the first part of the garniture where the edge without adhesive thereon is folded round the tobacco filler.

In British Patent Specification No.

1,299,722 it has, moreover, been proposed to apply a reactivatable adhesive to the two edges of the web which will become the inner and outer laps of the seam, the adhesive then being dried before entering the garniture; and when the web was wrapped around the filler the adhesive was reactivated by the use of a heater. However such a proposal again suffers from the attendant disadvantages of heaters and of the time required for the adhesive to set.

According to this invention there is provided a method of forming a continuous rod such as a cigarette rod or a filter rod, in which a filler is fed on to a wrapper web, the web is folded around the filler, and the two marginal portions of the web are secured together by adhesive to form a longitudinal seam, wherein a single continuous stripe of adhesive is applied to the web upstream of where the web is folded around the filler, the adhesive stripe being applied to the marginal portion of the web at the side thereof which will form the inner lap of said longitudinal seam.

The invention also extends to apparatus for forming a continuous rod such as a cigarette rod or a filter rod, comprising means for feeding a filler on to a wrapper web, garniture means for folding the web around the filler so that the two marginal portions of the web are overlapped to form a longitudinal seam, and adhesive applicator means upstream of the garniture means for applying a single continuous stripe of adhesive to the marginal portion of the web at the side thereof which will form the inner lap of said longitudinal seam.

According to another aspect of the invention, a method of forming a continuous rod in the tobacco processing industry comprises the steps of applying a stripe of adhesive to a marginal portion of one surface of a wrapper web, feeding a filler stream on to the surface of the web opposite said one surface, folding the web around the filler and bringing the other marginal portion of the web into overlapping bonding contact with the adhesive stripe of the first marginal portion.

Before the longitudinal seam is completed the filler for the rod may be compressed by a tongue whose position radial of the rod is automatically adjustable in response to a signal produced by a rod measuring means, so as to effect slight changes in the final diameter of the changes in the final diameter of the rod.

Applying the adhesive before the paper reaches the garniture allows the adhesive to be more precisely positioned on the paper, since- the paper may be more accurately controlled than when it is on the garniture tape. - This earlier application of the adhesive also allows the adhesive more fully to'penetrate the paper and to go more "tacky" before the bond is made.

This may produce a - better bond; and/or allow a smaller quantity of adhesive to be used. Also a shorter drying time, after the bond'has been made, may be possible.

The invention will now be - described, by way of example only, with reference to the accompanying drawings, in which: - Figures lA, lB and lC taken together are a side view of part of a continuous rod making machine according to the invention; Figure 2-is a view partly in section taken on the lines II-II of Figure - 1 C; and Figures 3 to 10 are sectional views taken on the lines III-III t6 X-X respectively of Figures lB and lC, but drawn to a larger scale.

Figures lA to lC show part of a continuous rod cigarette making machine known as the garniture. This comprises essentially a bed 1 formed in its upper surface with a trough 2 having a varying concave section, as will be described with reference to Figures 3 to 10. Running in the trough 2 is a garniture tape part of which has been omitted from Figure 2 for the sake of clarity. The tape 3 passes over pulley 4 before entering the upstream end of the garniture.

A web of paper 5 is fed over rollers 6 and 7 onto the tape 3. Between the rollers is a gluing nozzle 8 which applies a stripe 9 of polyvinyl acetate (PVA) adhesive (see Figure 2) to an edge of the web at the rear underside, as viewed in Figure 1A. The adhesive stripe 9 may be displaced slightly inwards from the edge of the web to leave a narrow margin, whose purpose will be explained below. The rear side- of the roller 7 has a relieved step 10 so that the adhesive stripe 9 does not contact the roller 7. While the adhesive stripe passes around the roller 7 at the step 10, centrifugal force urges the adhesive into the paper, thus improving the bond therebetween.

A stream of tobacco of rectangular section (Figure 3) is conveyed by a suction band 11 between a pair of walls 12. As the band 11 passes around a wheel 13 the tobacco is stripped off the band by a shoe 14 (Figure 4) which gradually changes the stream into a rounded section. As these parts, which are all shown chain-dotted in Figures 1, 3 and 4, are well known-in the art they will not be described in further detail.

To prevent tobacco or other particles from falling onto the paper web 5 before it reaches the garniture, a protecting plate 15 is mounted over the web.

As can be seen from Figure 3, the initial shape of the garniture trough 2 is a wide shallow curve, i.e. the initial radius of curvature of the trough 2 is large. On either side of the garniture bed 1 are primary folders 16 and 17 which continue the shallow curve of the trough 2 at the respective sides.

The shape of the folders 16 and 17 gradually changes, in moving downstream along the garniture bed 1 (i.e. from right to left as viewed in Figures 1B, 1C) from a triangular shape, as shewn in Figure 3, to a substantially rectangularshape (Fig.

4) as the folders 16, 17 extend past the sides of the shoe 14. At the same time the section of the trough changes to - become almost U-shaped, as also shown in Figure 4.

It should be noted that in Figures 1A to 1C the tobacco. and parts of the paper wéb and garniture tapel3 have been ornit- ted for the sake of clarity.

In the rear folder 17 a stepped cut-out 18 is provided along the position adjacent to the adhesive stripe 9 on the web. The level and depth of the cut-out 18 gradually increases in moving downstream along the folder 17 as shown in Figure 1B by the inclined lines 19.

The tobacco filler stream next leaves the shoe 14 and enters under a torque 20, the initial section of which can be seen in Figure 5. The tongue is of an unsymmetrical section having a progressively shallower section at the side of the web on which the adhesive stripe is, as shown in Figures 6 and 7.

Figure 8 shows the end of the tongue 20 before it finally disappears under a secondary folder 21 which forms a continuation of folder 17. By now the tape 3 has almost been brought around into a fully circular shape so that the paper web practically encloses the tobacco filler.

At this stage -the two edges of the paper web 5 radially spaced apart. Compared with the corresponding stage of operation of a conventional garniture, the inside edge of the paper is folded to a somewhat smaller radius than conventionally and the outside edge, instead of being substantially tangen tial to the partly formed rod, is folded over to a radius somewhat greater than that to which the inside edge is conventionally folded.

As the web 5 moves further through the garniture (Figure 9) the outside edge is brought down onto the inside edge by the folder 21 to form a continuous rod. Thus at the point where the two edges of paper are brought into contact and the seam is formed, the relative motion of the two edges is radial with respect to the rod.

There is no transverse sliding of one edge relative to the other, as the two edges are brought together, as would be the case if the two edges were brought into contact at the same time as they were folded around the tobacco filler. Such sliding might tend to produce creases in the paper along the seam.

The seam then passes under an iron 22 which holds it together for a short while to allow the PVA adhesive to dry fully. If necessary the iron 22 may be heated to accelerate the drying of the adhesive. But if heating of the iron 22 can be avoided, there is no need for the iron to be moved out of the path of the rod when the machine is not running normally. In that case the rod always remains closed, avoiding the conventional need to break the rod at start-up or shut-down of the machine, with the attendant wastage and degradation of tobacco.

Figure 10 also shows a pair of guide members 23 which allow the garniture tape gradually to open up again, while at the same time providing some support for the side of the rod.

When the two edges of the web are joined together, as shown in Figure 10, there is a small overlap of the outer edge beyond the stripe 9, due to the narrow margin on the inner edge from which ad hesive was omitted. This hides the adhesive stripe and gives a neat finish to the final cigarette. The size of this overlap may vary slightly to accommodate slight variations in the diameter of the continuous rod produced.

The tongue 2Q is preferably adjustably mounted, in order that the degree of final compression of the tobacco can be varied, which permits slight changes in the diameter of the rod. Such variations may be produced by an automatic tongue adjuster. Thus the diameter of the rod may be monitored downstream of the cut-off for the rod, and a signal fed back to the automatic adjuster to vary the position of the tongue so as to maintain the diameter within predetermined limits.

In conventional continuous rod making machines the garniture is in two parts with an adhesive applicator in between them, for example as shown in British patent specification No. 1,170,791. As the garniture in the present apparatus can be in one piece, it may be simpler - in construction and cheaper to make than conventional garnitures presently in use.

WHAT WE CLAIM IS: - -1. A method of forming a continuous rod such as a cigarette rod or a filter rod, in which a filler is fed on to a wrapper web, the web is folded around the filler, ~and the two marginal portions of the web are secured together by adhesive to form a longitudinal seam, wherein a single continuous stripe of adhesive is applied to the web upstream of where the web is folded around the filler, the adhesive stripe being applied to the marginal portion of the web at the side thereof which will form the inner lap of said longitudinal seam.

2. A method as claimed in claim 1 in which the adhesive stripe is spaced inward ly by a narrow margin from the edge of the web, so that in the completed rod the adhesive stripe is hidden by the narrow margin.

3. A method as claimed in claim 1 or claim 2 in which said two marginal por tions immediately prior to being secured together, are in overlapping relationship and travelling substantially parallel but radially spaced apart.

4. A method as claimed in any of claims 1 to 3, wherein the adhesive com prises polyvinyl acetate, which is of such a composition and is applied to the web at such an upstream position in relation to the speed of the web, that an adhesive bond is formed without the application of heat upon bringing said two marginal portions into contact.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

the folder 17 as shown in Figure 1B by the inclined lines 19.

The tobacco filler stream next leaves the shoe 14 and enters under a torque 20, the initial section of which can be seen in Figure 5. The tongue is of an unsymmetrical section having a progressively shallower section at the side of the web on which the adhesive stripe is, as shown in Figures 6 and 7.

Figure 8 shows the end of the tongue 20 before it finally disappears under a secondary folder 21 which forms a continuation of folder 17. By now the tape 3 has almost been brought around into a fully circular shape so that the paper web practically encloses the tobacco filler.

At this stage -the two edges of the paper web 5 radially spaced apart. Compared with the corresponding stage of operation of a conventional garniture, the inside edge of the paper is folded to a somewhat smaller radius than conventionally and the outside edge, instead of being substantially tangen tial to the partly formed rod, is folded over to a radius somewhat greater than that to which the inside edge is conventionally folded.

As the web 5 moves further through the garniture (Figure 9) the outside edge is brought down onto the inside edge by the folder 21 to form a continuous rod. Thus at the point where the two edges of paper are brought into contact and the seam is formed, the relative motion of the two edges is radial with respect to the rod.

There is no transverse sliding of one edge relative to the other, as the two edges are brought together, as would be the case if the two edges were brought into contact at the same time as they were folded around the tobacco filler. Such sliding might tend to produce creases in the paper along the seam.

The seam then passes under an iron 22 which holds it together for a short while to allow the PVA adhesive to dry fully. If necessary the iron 22 may be heated to accelerate the drying of the adhesive. But if heating of the iron 22 can be avoided, there is no need for the iron to be moved out of the path of the rod when the machine is not running normally. In that case the rod always remains closed, avoiding the conventional need to break the rod at start-up or shut-down of the machine, with the attendant wastage and degradation of tobacco.

Figure 10 also shows a pair of guide members 23 which allow the garniture tape gradually to open up again, while at the same time providing some support for the side of the rod.

When the two edges of the web are joined together, as shown in Figure 10, there is a small overlap of the outer edge beyond the stripe 9, due to the narrow margin on the inner edge from which ad hesive was omitted. This hides the adhesive stripe and gives a neat finish to the final cigarette. The size of this overlap may vary slightly to accommodate slight variations in the diameter of the continuous rod produced.

The tongue 2Q is preferably adjustably mounted, in order that the degree of final compression of the tobacco can be varied, which permits slight changes in the diameter of the rod. Such variations may be produced by an automatic tongue adjuster. Thus the diameter of the rod may be monitored downstream of the cut-off for the rod, and a signal fed back to the automatic adjuster to vary the position of the tongue so as to maintain the diameter within predetermined limits.

In conventional continuous rod making machines the garniture is in two parts with an adhesive applicator in between them, for example as shown in British patent specification No. 1,170,791. As the garniture in the present apparatus can be in one piece, it may be simpler - in construction and cheaper to make than conventional garnitures presently in use.

WHAT WE CLAIM IS: - -1. A method of forming a continuous rod such as a cigarette rod or a filter rod, in which a filler is fed on to a wrapper web, the web is folded around the filler, ~and the two marginal portions of the web are secured together by adhesive to form a longitudinal seam, wherein a single continuous stripe of adhesive is applied to the web upstream of where the web is folded around the filler, the adhesive stripe being applied to the marginal portion of the web at the side thereof which will form the inner lap of said longitudinal seam.
2. A method as claimed in claim 1 in which the adhesive stripe is spaced inward ly by a narrow margin from the edge of the web, so that in the completed rod the adhesive stripe is hidden by the narrow margin.
3. A method as claimed in claim 1 or claim 2 in which said two marginal por tions immediately prior to being secured together, are in overlapping relationship and travelling substantially parallel but radially spaced apart.
4. A method as claimed in any of claims 1 to 3, wherein the adhesive com prises polyvinyl acetate, which is of such a composition and is applied to the web at such an upstream position in relation to the speed of the web, that an adhesive bond is formed without the application of heat upon bringing said two marginal portions into contact.
5. Apparatus for forming a continuous

rod such as a cigarette rod or a filter rod, comprising means for feeding a filler on to a wrapper web, garniture means for folding the web around the filler so that the two marginal portions of the web are overlapped to form a longitudinal seam, and adhesive applicator means upstream of the garniture means for applying a single continuous stripe of adhesive to the marginal portion of the web at the side thereof which will form the inner lap of said longitudinal seam.
6. Apparatus as claimed in claim 5, further comprising a roller around which the web passes before entering the garniture means, the roller being disposed downstream of the adhesive applying means and engaging the surface of the web which will become the outside of the continuous rod, wherein a relieved step is provided on the roller at the side thereof corresponding to said marginal portion to which the adhesive stripe is applied, so that the adhesive stripe is urged into the web by centrifugal force as the web passes around the roller.
7. Apparatus as claimed in claim 5 further comprising a plate extending between said roller and the means for feeding the filler on to the web, so that particles of the filler are prevented from dropping on to the web in the vicinity of the adhesive stripe.
8. Apparatus as claimed in any of claims 5 to 7, in which the garniture means comprises a tongue for compressing the filler before the longitudinal seam is completed, and means to adjust the position of the tongue radially of the rod, so as to effect slight changes in the diameter of the rod.
9. A method of forming a continuous rod in the tobacco processing industry, comprising the steps of applying a stripe of adhesive to a marginal portion of one surface of a wrapper web, feeding a filler stream on to the surface of the web opposite said one surface, folding the web around the filler and bringing the other marginal portion of the web into overlapping bonding contact with the adhesive stripe of the first marginal portion.
10. A method of forming a continuous rod substantially as herein described with reference to, and as shown in, the accompanying drawings.
11. Apparatus for forming a continuous rod substantially as herein described with reference to, and as shown in, the accomDanvinsr drawings.