[0001] A Method of Producing Cheroots and Similar Tobacco Articles and an Apparatus for
Preparing Wrappers by this Method.
[0002] 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.
[0003] 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.
[0004] Also within other branches of the cigar production the ribs of tobacco leaves give
rise to difficulties, and even the French patent specification No. 572,737 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 utilized as cigar filler material.
[0005] A corresponding proposal, exclusive of the step of heating, has been presented in
the still older German patent No. 149,491.
[0006] 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.
[0007] Recent tests have proved that a cut wrapper with side ribs that 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 also 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.
[0008] Starting from the prior art discussed above, the invention relates to a method of
manufacturing cheroots and similar tobacco articles comprising a wrapper cut out from
natural tobacco and including parts of the side ribs of the tobacco leaf. 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.
[0009] This is achieved, according to the invention, by subjecting the moist tobacco leaf,
or the wrapper cut out from it, to a rolling operation between a hard and a comparatively
soft surface to flatten out the side ribs at least in the end flap of the wrapper.
[0010] It has not been fully elucidated why such a rolling between two differently hard
surfaces 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 quite
plane foil (the mesophyll) with uniformly located thickenings (the ribs), since naturally
determined varieties 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 thinkable that the shearing forces between the mesophyll and the leaf rib caused
by such varieties are compensated to a sufficient degree due to the slightly deformable
character of the 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.
[0011] Irrespective of whether the rolling operation is carried out prior to the cutting-out
of wrappers, i.e. of the stripped tobacco leaves, or subsequent to the cutting operation,
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.
[0012] 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 on a bobbin subsequent to the cutting operation
instead of applying them immediately to the overrolling operation..By use of this
technique the method according to the invention may appropriately be practised in
the way that the cloth of the bobbin during the winding or unwinding thereof is used
as the comparatively soft surface in connection with a hard roller. This implies that
the extra equipments needed to carry out the method are reduced to a minimum, since
they for instance only consist in a pair of driven or idling squeeze rollers between
which the bobbin cloth passes during winding and unwinding the wrappers.
[0013] The invention further relates to an apparatus for preparing wrappers according to
the method concerned, said apparatus being characterised in that it comprises a side
rib flattening device including a rotatable roller and an associated base, one of
the said components having a.hard surface while the other has a comparatively soft
surface. This comparatively soft surface suitably consists of a bobbin cloth running
over a roller.
[0014] 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.
[0015] 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 by 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.
[0016] 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.
1. A method of manufacturing cheroots and similar tobacco articles comprising a wrapper
cut out from natural tobacco and including parts of the side rib of the tobacco leaf,
characterised in that the tobacco leaf, or the wrapper (3) cut out from it, in moist
condition is subjected to a rolling operation between a hard surface (11) and a comparatively
soft surface (4,11) to flatten out the side ribs (13) at least in the end flap of
the wrapper.
2. A method according to claim 1 and in which the wrappers are wound on a bobbin (2)
subsequent to the cutting operation, characterised in that the cloth (4) of the bobbin
during the winding or unwinding thereof is used as the comparatively soft surface
in connection with a hard roller (11).
3. An apparatus for preparing wrappers by the method set forth in claim 1 or 2, characterised
in that it comprises a side rib (13) flattening device including a rotatable roller
(11) and an associated base (4,11),one of the said components having a hard surface
while the other has a comparatively soft surface.
4. An apparatus as claimed in claim 3, characterised in that the comparatively soft
surface is constituted by a bobbin cloth.(4) running over a roller (11).