EP0021788B1

EP0021788B1 - A method of producing cheroots and similar tobacco articles and an apparatus for preparing wrappers by this method

Info

Publication number: EP0021788B1
Application number: EP19800302057
Authority: EP
Inventors: Ian Kjaer; Niels Erik Mortensen
Original assignee: SKANDINAVISK TOBAKSKOMPAGNI AS
Current assignee: SKANDINAVISK TOBAKSKOMPAGNI AS
Priority date: 1979-06-19
Filing date: 1980-06-18
Publication date: 1983-04-20
Also published as: DE3062813D1; ES8101862A1; ES492536A0; EP0021788A1; DK144455C; DK256179A; DK144455B

Description

In the production of cheroots and similar tobacco articles having a wrapper of natural tobacco no parts of the vein or central rib of the tobacco leaf are tolerated in the wrapper. Therefore, the vein is either removed from the tobacco leaf prior to stamping or cutting out the wrapper, or care is taken to locate the stamping cuts so as not to interfere with the central rib. On the other hand, parts of the side ribs of the leaf are accepted in the wrapper, but by the stamping operation it is attempted to avoid side rib parts in the end flap of the wrapper, i.e. the portion that forms rather over the last turn of the wrapper when overrolled. This is due to the fact, firstly, that side rib parts in the end flap irritate the lips, in particular if the wrapper is rolled over with the wrong or lower side outward which is frequently preferred with a view to the appearance of the finished cheroot and, secondly, that such side rib parts might cause the tip of the cheroot to be less resistant to mechanical damage.
As far as singular stamping-out operations are concerned, the operator may have this in mind when locating the leaf on the stamp or cutting tool, but in this case a certain waste of the comparatively expensive wrapper material must often be allowed for, because the number of possible cuts per leaf is reduced. The same applies to multi-stamping, i.e. when simultaneously using two or more stamps, and these tools must furthermore be mutually adjustable in order to fulfil the purpose, whereby the machinery and wage costs are considerably increased. A further known possibility is the cutting up of tobacco leaves into shreds or strips with a width corresponding to the width of the wrappers to be used and, after defective portions having been cut away, gluing these strips together into a consecutive tape from which the wrappers are cut out so as to avoid side rib parts in the end flaps. These operations may be controlled automatically, but for this purpose extremely expensive machinery is required.
Also within other branches of the cigar production the ribs of tobacco leaves give rise to difficulties, and even the FR-A-572737 that was published more than 50 years ago includes a proposal for evading such difficulties in connection with the preparation of filler tobacco. According to this proposal whole tobacco leaves are moistened just sufficiently so that they can be manually spread out or smoothed and are then heated, for example to 100°C, with a view to soften the ribs, in particular the central rib, whereafter the leaves when still moist and hot are passed between a pair of squeeze rollers for flattening of the ribs. The said reference states that the entire tobacco leaf including its ribs but with the exception of its stem can then be utilised as cigar filler material.
A corresponding proposal, exclusive of the step of heating, has been presented in the still older DE-C-149,491, and US-A-2,519,304 discloses an apparatus for crushing the stems of green tobacco leaves before they are strung onto tobacco sticks for curing operation, for the purpose of causing the leaves to dry more readily than if the stems were not crushed.
A similar flattening has presumably been attempted in the processing of wrappers subsequent to the removal of the central rib of the leaves, but this does not appear to be described in literature.
Recent tests have proved that a cut wrapper with side ribs have been flattened by use of the technique known from the cited patent specifications may be acceptable even though it contains rib parts in its end flap, as these side rib parts have lost a considerable portion of their rigidity and thickness, but it has alos been found that an efficient flattening causes a material weakening of the mechanical strength of the leaf, particularly in the immediate vicinity of the ribs. In some cases the flattening operation was followed by a virtual perforation, inasmuch as the mesophyll was locally torn off the ribs, while the leaves in other cases apparently remained undamaged but, nevertheless, had been weakened so much that breakage or perforation showed up along the ribs in the subsequent overrolling operation.
Starting from the prior art discussed above, the invention relates to a method of manufacturing cheroots and similar tobacco articles having a wrapper that is cut out from natural tobacco and includes parts of the side ribs of the tobacco leaf and which subsequent to the cutting operation is stored in a bobbin of cloth. The invention aims at providing a method of this type and so improved that the side ribs - by flattening and without undue weakening of the mechanical strength of the leaf - may be deformed to such a degree that they are tolerable even in the end flap of the wrapper..
This is achieved, according to the invention, by subjecting the wrapper in moist condition and while lying on the cloth of the bobbin during the winding or unwinding thereof, at least as far as the end flap of the wrapper is concerned, to a rolling operation between a hard surface and the comparatively softer surface formed by the bobbin cloth, to flatten out the side ribs.
It has not been fully elucidated why such a rolling between two surfaces of differing hardness on the one hand makes it possible to achieve the desired flattening of the ribs and, on the other hand, reduces the tendency to breakage, but a conceivable explanation is that a tobacco leaf even though carefully smoothed does not constitute a wholly plane foil (the mesophyll) with uniformly located thickenings (the ribs), since naturally determined variations from such a structure are prevailing, including local variations of the rib thickness, inter alia in connection with the secondary side ribs, and it is conceivable that the shearing forces between the mesophyll and the leaf rib caused by such variations are compensated to a sufficient degree due to the slightly deformable character of one rolling surface and so do not damage the leaves as it has been the case under other circumstances. Apparently, it does not matter how the leaves are turned during the rolling process, i.e. whether the wrong or lower side with protruding ribs faces the hard surface or whether the right or upper side does.
By the method of the invention, considerable savings are made possible as far as the production of wrappers is concerned, because the wrappers may be cut out without regard to a special or optimum location of the rib parts.
Among the objects of the endeavours of rationalization made within the field of cigar production is that of separating the wrapper cutting operation from the overrolling operation, viz. by winding the wrappers between layers of cloth on a bobbin subsequent to the cutting operation instead of applying them immediately to the overrolling operation. By use of this technique the extra items of equipment needed to carry out the method are reduced to a minimum, since they for instance only consist in a pair of driven or idling squeese rollers between which the bobbin cloth passes during winding or unwinding the wrappers.
The invention further relates to an apparatus for preparing wrappers according to the method of the invention, said apparatus being characterised in that it comprises a side rib flattening device including a rotatable roller with a hard surface to be pressed against the wrappers lying on the bobbing cloth running over another roller on its way to or away from the bobbin.
An embodiment of such an apparatus is more specifically explained in the following with reference to the drawing, which in perspective shows the relevant parts of the apparatus.
The apparatus includes a framework, not shown, in which a bracket 1 is disposed to receive a bobbin 2 with wrappers 3 cut out in a previous operation. The bobbin cloth 4 is pulled off in the direction of the arrows by means of a pair of co-operating driving rollers 5, after which the cloth may be wound for renewed use. During the pulling-off operation the bobbin cloth 4 passes across a table 6 that may contain a suction box contributing to holding the wrappers 3 against the cloth till they reach a take-off position from which they are transferred to a roll-making machine by means of a transfer mechanism 7 having a suction mouth piece 9 mounted on a pivot arm 8. The said roll-making machine is simply symbolized by a bloc 10 on the drawing. As indicated by the arrows, the pivot arm 8 and with it also the suction mouth piece 9 may be subjected to a vertical movement of displacement as well as to a movement of rotation, said movements being supposed to be conventionally co-ordinated with the advance movement of the bobbin cloth 4.
The bobbin cloth 4 and the wrappers 3 lying on it enter the table 6 via a pair of rollers 11 having a hard surface, for instance steel rollers, and provided with gear wheels 12 to secure the same circumferential velocity of both rollers. The wrappers 3 are subjected to a squeezing operation between said rollers 11 with the purpose of achieving a flattening of the side rib portions 13 occurring in the leaves, the bobbin cloth during this step acting as a comparatively soft coating on the lower roller whereby to prevent the wrappers from being mechanically damaged, in particular with a view to impede detachment of the mesophyll from the side ribs.

Claims

1. A method of manufacturing cheroots and similar tobacco articles having a wrapper (3) that is cut out from natural tobacco and includes parts of the side ribs (13) of the tobacco leaf and which subsequent to the cutting operation is stored in a bobbin (2) of cloth, characterized in that the wrapper (3) in moist condition and while lying on the cloth (4) of the bobbin during the winding or'unwinding thereof is subjected, at least as far as the end flap of the wrapper is concerned, to a rolling operation between a hard surface (11) and the comparatively softer surface formed by the bobbin cloth, to flatten out the side ribs (13).

2. An apparatus for preparing wrappers by the method set forth in claim 1 and comprising a bobbin (2) of cloth for storing the wrappers between the cutting and overrolling operations, characterized in that the apparatus further comprises a side rib (13) flattening device including a rotatable roller (11) with a hard surface to be pressed against the wrappers (3) lying on the bobbin cloth (4) running over another roller (11) on its way to or away from the bobbin (2).