Note: Descriptions are shown in the official language in which they were submitted.
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TITLE OF THE INVENTION
SMOKING ARTICLE WITH CLOSED END AND METHODS AND APPARATUS
FOR MANUFACTURE THEREOF
BACKGROUND OF THE INVENTION
The present invention relates to smoking articles having closed ends, and
methods and apparatus for making smoking article having closed ends.
Manufactured smoking articles such as cigarettes conventionally comprise a
tobacco rod having a wrapping of cigarette paper, and a filter attached to the
tobacco
rod by a tipping paper, although plain cigarettes, lacking a filter, are also
available. In
either case, the end of the cigarette which is intended to be lit is often
open, so that the
tobacco inside the cigarette paper is exposed. This allows leakage or spillage
of
tobacco from the cigarette, and also allows contaminants and foreign bodies to
enter
the tobacco.
It has been previously proposed to close one or both ends of a cigarette by
folding or otherwise manipulating a portion of the cigarette paper that
extends beyond
the tobacco rod. For example, US 1,164,118 describes a cigarette-making
machine that
forms a tube of cigarette paper, closes one end of the tube, fills the tube
with tobacco,
and then closes the other end. Both -closures are achieved by components that
grip the
tube ends and rotate to twist the paper while the tube is held stationary. US
501,498
describes a machine that wraps cigarette paper around tobacco, compresses the
tobacco from both ends to make paper overhangs for folding, and then closes
each end
of the paper using two tuckers that push the paper over and a conical head
that is
inserted into the end of the closed cigarette and rotated to force the paper
inwards and
smooth it. The cigarette is held still while the closure components move. US
903,101
describes a machine that forms a tube of cigarette paper and closes one end
before
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filling the tube with tobacco. The closure is effected by a notched plate that
slides over
the end of the tube and back again, while both tube and plate are moving along
the
longitudinal direction of the tube. US 3,208,458 describes a machine that
wraps
cigarette papers around tobacco, the papers having scalloped edges. The
cigarette is
then held still while a series of three blades spaced 120 apart move in and
out against
the ends of the cigarette to fold over the separate flaps of the scalloped
edges of the
paper. GB 278,534 describes a cigarette with the cigarette paper turned
inwardly over
the end of the wrapped tobacco to form a tubular extension into the tobacco
that
partially covers the tobacco.
However, these various approaches to closing the end of a cigarette are not at
all recent, and are hence not well-suited to modern cigarette manufacturing
techniques.
The present invention aims to provide closed end cigarettes using methods and
apparatus that are more compatible with current cigarette manufacturing
machinery.
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SUMMARY OF THE INVENTION
Accordingly, a first aspect of fne present invention is directed to- a method
of
making a smoking article, comprising: providing a fully or partially
fabricated
smoking article comprising at least a tobacco rod of tobacco wrapped in
cigarette
paper; adhering a foldable paper to the cigarette paper such that the foldable
paper
encircles the tobacco rod and overhangs the cigarette paper at an end of the
tobacco
rod that is intended to be lit; and folding the overhanging foldable paper to
substantially cover the tobacco at the end of the tobacco rod. The foldable
paper may
be adhered to the outside of the cigarette paper.
It has been found that closing the end of a smoking article by folding over a
separately applied outer layer of paper has advantages over methods that rely
on
folding over an extension of the cigarette paper itself. It is possible, for
example, to
obtain an extending portion of the cigarette paper by tapping the smoking
article or
standing it on its filter end on a vibrating table to cause the tobacco to
settle further
down inside the cigarette paper. However, the tobacco (smoking material) is of
a non-
uniform nature and hence different components will settle to different levels,
and give
an inconsistency to the smoking quality. Alternatively, the tobacco can be
pressed
down inside the cigarette paper, but this gives a non-uniform density that
again results
in an inconsistent smoking quality. Wrapping a separate foldable paper around
the
cigarette paper removes any need to redistribute or otherwise manipulate the
tobacco
once the smoking article has been assembled, so that quality can be
maintained. Also,
keeping the tobacco rod in the structure in which it is initially fabricated
maintains the
clean flat cut end of the tobacco, which offers a much better surface against
which the
fold the foldable paper than can be obtained through tapping, vibrating or
compressing, which tend to modify the tobacco surface and make it less flat
and
robust. Hence the folding can be more easily and efficiently performed, and
the
resulting folded end can have a neater appearance.
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Any paper that can be folded over to close the end of the tobacco rod can be
used, for example, standard cigarette paper as used to wrap the tobacco and
form the
tobacco rod. However, a porous paper is beneficial, as it makes it easier for
the smoker
to draw on the cigarette when lighting it, since more air can flow through the
paper.
Also, porous paper is typically thinner and lighter than standard cigarette
paper, so that
it can be folded more easily and neatly, giving a more compact folded end.
Therefore,
in some embodiments, the foldable paper is a lighter weight paper than the
cigarette
paper. For example, the foldable paper may have a porosity greater than 3,000
CU, or
greater than 6,000 CU, or greater than 12,000 CU, or greater than 24,000 CU.
In some
embodiments, the foldable paper may be porous plug wrap paper. This is
particularly
thin and light with ample porosity so as not to impede drawing, and is further
already
readily available in the tobacco industry.
The foldable paper may be embossed with one or more crease lines along
which the overhanging foldable paper is folded. Providing such crease lines
facilitates
the paper folding, in that folding becomes easier as less force is needed to
bend the
paper, and the folds more readily form in the intended positions. This gives a
more
consistent appearance to the folded end. The foldable paper may be provided
pre-
embossed. Alternatively, the method may further comprise, before adhering the
foldable paper to the cigarette paper, embossing the foldable paper with one
or more
crease lines along which the overhanging foldable paper is to be folded.
The foldable paper encircling the tobacco rod may extend over only part of-the
length of the tobacco rod, or alternatively the foldable paper encircling the
tobacco rod
may extend over substantially the whole length of the tobacco rod. The former
arrangement allows a minimum amount of paper to be used, thus saving materials
and
reducing costs. The latter arrangement, if applied to a partially completed
smoking
article lacking a filter, allows the edge of the foldable paper remote from
the
overhanging part to be covered with tipping paper when the filter is attached
to the
tobacco rod. This gives a neat appearance to the smoking article and also
removes an
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exposed edge that could otherwise become caught or torn during. later handling
of the
smoking article.
In some embodiments, adhering the foldable paper to the cigarette paper
comprises: applying adhesive to the foldable paper; bringing the smoking
article into
contact with the foldable paper such that an edge of the foldable paper
adheres to the
cigarette paper; and carrying the smoking article in a vacuum flute on the
outer surface
of a rotating drum, the smoking article arranged with its longitudinal axis
parallel to
the rotation axis of the drum, so as to bring the smoking article into contact
with a
curved static plate spaced apart from the drum by a distance less than the
diameter of
the smoking article, contact with the plate causing the smoking article to
rotate about
its own longitudinal axis so that it rolls over the plate as the drum rotates,
the rolling
causing the foldable paper to wrap around the smoking article. Since this
technique
relies on individual pieces of foldable paper applied to individual smoking
articles, it
is suitable for a foldable paper that extends over any length of the tobacco
rod. It is
merely necessary to use an appropriately sized foldable paper at the start of
the
process. Rotating drums with vacuum flutes are widely used in smoking article
manufacture, so an existing production line may be readily adapted to 'include
apparatus for performing this method of applying the foldable paper.
Further, for embodiments in which the foldable paper is applied as a
individual
piece, the foldable paper may be shaped along an edge such that the
overhanging
foldable paper has an edge profile that gives a reduced amount of overlapped
paper
after folding compared to a straight edge. This can be used to give a neater
appearance
to the folded end, and may also give a fold arrangement that maintains its
folded
position better with less tendency for the folds to spring apart after
folding.
In other embodiments, adhering the foldable paper to the cigarette paper
comprises: arranging the smoking article in a sequence of smoking articles
arranged
end to end but spaced apart by a distance equal to the desired length of the
overhanging foldable paper; feeding the sequence of smoking articles onto a
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continuous length of foldable paper, the foldable paper having a width at
least equal to
the circumference of the tobacco rods; wrapping the foldable paper around= the
smoking articles to encircle the tobacco rods, and adhering it in place; and-
cutting
through the foldable paper flush to an end of each smoking article, to
separate the
smoking articles and form the overhanging foldable paper. Alternatively,
adhering the
foldable paper to the cigarette paper may comprise: arranging the- smoking
article in a
sequence of smoking articles arranged end to end in pairs where the articles
in each
pair abut at their adjacent ends and the pairs are spaced apart by a distance
equal to
twice the desired length of the overhanging foldable paper; feeding the
sequence of
smoking articles onto a continuous length of foldable paper, the foldable
paper having
a width at least equal to the circumference of the smoking articles; wrapping
the
foldable paper around the smoking articles to encircle the tobacco rods, and
adhering
it in place, and cutting through the foldable paper where the smoking articles
in each
pair abut and also at the midpoint of the spaces between the pairs, to
separate the
smoking articles and form the overhanging foldable paper. These techniques
give a
foldable paper that extends over the full length of the tobacco rod. The
techniques can
be implemented by adapting apparatus currently used for applying a second
paper
layer to double-wrapped tobacco rods.
In various embodiments, folding the overhanging foldable paper may comprise
carrying the smoking article in a vacuum flute on the outer surface of one or
more
rotating drums so as to bring the overhanging foldable paper into contact with
one or
more folding devices that bend the overhanging foldable paper inwards over the
tobacco at the end of the tobacco rod. As mentioned above, rotating drums with
vacuum flutes are already commonly used in smoking article production, so
their
application to the methods of the present invention allows the invention to be
conveniently implemented without extensive investment in new and complex
apparatus.
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A variety of folding devices may be employed to achieve different folding
effects and number of folds. For example, the one or more folding devices may
comprise -a reciprocating tucker with a width less than the diameter of the
smoking
article that extends partially over the end of the tobacco rod flush with the
tobacco
therein to create a first fold and then retracts, a fixed tucker with a width
less than the
diameter_ of the tobacco rod and a surface that is flush with the tobacco
against which
the end of the tobacco rod passes to create a second fold opposite the first
fold, and a
pair of static plough folders providing surfaces flush with the tobacco and
having
oppositely disposed converging edges, against which the end of tobacco rod
passes to
form third and fourth folds opposite one another and orthogonal to the first
and second
folds. This gives a four-way envelope-style fold.
Alternatively, the one or more folding devices may comprise a curved static
plate spaced apart from the rotating drum by a distance less than the diameter
of the
smoking article, contact with the plate causing the smoking article to rotate
about its
own longitudinal axis so that it rolls over the plate as the drum rotates, and
a plough
folder fixed to the plate and comprising a surface flush with the end of the
tobacco rod
that has an edge that converges towards the drum in the direction of rotation
of the
drum such that as the smoking article rolls over the plate the end of the
tobacco rod
passes against the surface and the overhanging foldable paper is engaged by
the
converging edge and is gradually folded inwards over the tobacco in a
continuous
fold.
In a further alternative, the one or more folding devices may comprise a
curved
static plate spaced _apart from the rotating drum by a distance less than the
diameter of
the smoking article, contact with the plate causing the smoking article to
rotate about
its own longitudinal axis so that it rolls over the plate as the drum rotates,
and a
sequence of teeth extending from the plate towards the drum and having
surfaces flush
with the end of the tobacco rod, each tooth engaging a part of the overhanging
foldable paper and creating a fold as the smoking article rolls over the
plate, each fold
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overlapping the previous fold. This produces an iris-style fold, where the
number of
individual overlapping folds is determined by the number of teeth. Hence, the
number
of teeth can be sel-ected to achieve a particular appearance of the iris fold.
In another alternative, the one or more folding devices may comprise a curved
static plate spaced apart from the rotating drum by a distance less than the
diameter of
the smoking article, contact with the plate causing the smoking article to
rotate about
its own longitudinal axis so that it rolls over the plate as the drum rotates,
and a
rotatable cam associated with each vacuum flute on the rotating drum, each cam
having a surface flush with the end of the tobacco rod and configured to sweep
across
the end of the tobacco rod as the smoking article rolls over the plate, the
edge of the
cam pushing against the overhanging foldable paper to fold it inwards over the
tobacco. In this context, the cam may have a smooth edge that creates a
continuous
fold, or alternatively the cam may have a toothed edge that creates a series
of
overlapping folds. This latter option gives an iris fold in which the number
of folds
corresponds to the number of teeth.
In a yet further alternative, the one or more folding devices may comprise a
pair of adjacent rotatable surfaces flush with the end of the tobacco rod that
sweep
outwardly over the end of the tobacco rod from the rear of the smoking article
as it is
carried by the rotating drum to create first and second adjacent folds, and a
static
tucker having a surface flush with the end of the tobacco rod against which
the end of
the tobacco rod passes to create a third fold. This gives a three-way fold.
In another embodiment, the one or more folding devices may comprise a
curved static plate spaced- apart from the rotating drum by a distance less
than the
diameter of the smoking article, contact with the plate causing the smoking
article to
rotate about its own longitudinal axis so that it rolls over the plate as the
drum rotates,
and a rotating threaded screw positioned with its axis of rotation orthogonal
to the axis
of rotation of the rotating drum and substantially tangential to the perimeter
of the
drum, and the threaded surface flush with the end of the tobacco rod such that
the
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screw thread engages with the overhanging foldable paper as the smoking
article rolls
across the plate and the rotation of the screw folds the paper inwards over
the tobacco.
A number of individual overlapping folds are produced, giving an iris-style
fold. The
pitch of the screw thread determines the number of folds.
In a further embodiment, the one or more folding devices may comprise a
protrusion in a vacuum flute of a first rotating drum that pushes part of the
overhanging foldable paper inwards over the tobacco when the smoking article
enters
the vacuum flute to create a first fold, a further protrusion in a vacuum
flute of a
second, adjacent, rotating drum to which the smoking article is transferred
from the
first drum, the further protrusion pushing part of the overhanging foldable
paper
inwards over the tobacco when the smoking article enters the flute to create a
second
fold opposite the first fold, and a pair of static, plough folders providing
oppositely
disposed surfaces flush with the end of the tobacco rod and having converging
edges,
against which the end of tobacco rod passes to create third and fourth folds
opposite
one another and orthogonal to the first and second folds. This produces a four-
way
envelope fold.
In an alternative embodiment, the one or more folding devices may comprise a
protrusion in a vacuum flute of a first rotating drum that pushes part of the
overhanging foldable paper inwards over the tobacco when the smoking article
enters
the vacuum flute to create a first fold, a further protrusion in a vacuum
flute of a
second, adjacent, rotating drum to which the smoking article is transferred
from the
first drum, the further protrusion pushing part of the overhanging foldable
paper
inwards over the tobacco when the smoking article enters the flute to create a
second
fold opposite the first fold, and a pair of reciprocating folders that sweep
inwardly
over the end of the tobacco rod and then retract to create third and fourth
folds
opposite one another and orthogonal to the first and second folds. Again, a
four-way
envelope fold is produced.
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Alternatively, the one or more folding devices may comprise a protrusion in a
vacuum flute of a first rotating drum that pushes part of the overhanging
foldable
paper inwards over the tobacco when the smoking article enters the vacuum
flute to
create a first fold, a further protrusion in a vacuum flute of a second,
adjacent, rotating
drum to which the smoking article is transferred from the first drum, the
further
protrusion pushing part of the overhanging foldable- paper inwards over the
tobacco
when the smoking article enters the flute to create a second fold opposite the
first fold,
a fixed folder disposed at the side of a vacuum flute of a third, adjacent,
rotating drum
to which the smoking article is transferred from the second drum which engages
with
the overhanging foldable paper as the smoking article enters the vacuum flute
and
pushes the paper inwards over the tobacco to create a third fold orthogonal to
the first
and second folds, and a further fixed folder disposed at the side of a vacuum
flute of a
fourth, adjacent, rotating drum to which the smoking article is transferred
from the
third drum which engages with the overhanging foldable paper as the smoking
article
enters the vacuum flute and pushes the paper inwards over the tobacco to
create a
fourth fold opposite to the third fold. This is further alternative way to
produce a four-
way envelope fold.
In any of the above methods including protrusions in vacuum flutes, one or
both of the said protrusion and the further protrusion may be configured to
move
between an extended position for effecting the first or second fold as the
smoking
article enters the vacuum flute, and a retracted position after the fold is
effected in
which the protrusion does not protrude into the flute. Retracting the
protrusion after
folding allows further motion of the smoking article to proceed with less
impediment,
giving a smoother. production process. Also, the gradual folding motion of a
moving
protrusion can produce a better quality fold than the more abrupt impact
between a
smoking article and a fixed protrusion. .
In another embodiment, the one or more folding devices may comprise a first
pair of pincers longitudinally aligned with a vacuum flute of a first rotating
drum, and
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biased in an open position to receive the overhanging foldable paper of a
smoksng
article in the vacuum flute, the pincers operable to close on the received
overhanging
foldable paper and push opposite parts of the paper inwards over th-e tobacco
to create
opposite first and second folds, and a second pair of pincers longitudinally
aligned
with a vacuum flute of a second rotating drum, and biased in a open position
to receive
the overhanging foldable paper of the smoking article when transferred to the
vacuui-n
flute after folding in the vacuum flute of the first rotating drum, the
pincers operable to
close on the remaining overhanging foldable p-aper and push the opposite parts
of the
paper inwards over the tobacco to create opposite third and fourth folds
orthogonal to
the first and second folds.
Alternatively, the one or more folding devices may comprise a first pair of
pincers longitudinally aligned with a vacuum flute of a first rotating drum,
and biased
in an open position to receive the overhanging foldable paper of a smoking
article in
the vacuum flute, the pincers operable to close on the received overhanging
foldable
paper and push opposite parts of the paper inwards over the tobacco to create
opposite
first and second folds, and one or xnore supplementary folding devices
associated with
a second rotating drum arranged to receive the smoking article after folding
with the
first drum, and operable to fold the remaining opposite parts of the paper
inwards over
the tobacco to create opposite third and fourth folds orthogonal to the first
and second
folds.
According to further embodiments, adhering the foldable paper to the cigarette
paper may comprise: applying adhesive to the foldable paper; bringing the
smoking
article into contact with the foldable paper such that an edge of the foldable
paper
adheres to the cigarette paper; and introducing the smoking article onto a
lower
surface that is spaced apart from an upper surface by a distance less than the
diameter
of the smoking article, the upper surface moving relative to the lower surface
along a
direction parallel to the surfaces and orthogonal to the longitudinal axis of
the smoking
articles such that contact with the surfaces causes the smoking article to
rotate about
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its longitudinal axis so that it rolls over the lower surface as the upper
surface moves,
the rolling causing the foldable paper -to wrap around the smoking article.
The upper
surface may comprise an endTess belt rotating around a-pair of rollers.
Further, folding the overhanging paper may then comprise using the rolling of
the smoking article over the lower surface to bring the over-hanging foldable
paper into
contact with one or more folding devices that bend the overhanging foldable
paper
inwards over the tobacco at the end of the tobacco rod. The one or more
folding
devices may comprise a series of teeth extending from the lower surface
towards the
upper surface and having surfaces flush with the end of the tobacco rod, each
tooth
engaging a part of the overhanging foldable paper and creating a fold as the
smoking
article rolls over the lower surface, each fold overlapping the previous fold.
Other
folding devices may alternatively be used, however.
Folding the overhanging foldable paper may comprise pushing part of the
paper inwards to create a first fold, pushing a further part of the paper
inwards to
create a second fold opposite the first fold, and trimming off some or all of
the
remaining, unfolded paper. This reduces the amount of overlapping paper in the
folded
end, making the. smoking article easier to light.
The method may further comprise, after folding the overhanging foldable
paper, pushing against the end of the tobacco rod with a pin having a width
less than
the diameter of the smoking article to depress the folded paper and cause it
to better
maintain its folded position. This is a simple way to overcome any tendency of
the
folded paper to spring outwards slightly from its folded position, and is
preferable to
the use of adhesive to hold the folded end in place.
In some embodiments, the foldable paper is provided with adhesive on all or
part of the inner surface of the overhanging portion, and the method further
comprises,
after folding the overhanging paper, pressing against the end of the tobacco
rod to
cause the folded paper to become adhered in its folded position. The adhesive
may be
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heat-activated, and pressing against the end of the tobacco rod may include
applying
heat to the end of the tobacco rod.
Also, the method may further comprise, in the event that the smoking article
is
a partially fabricated. smoking article, attaching a filter unit to the end of
the tobacco
5. rod opposite to the end intended to be lit. To speed production, the filter
unit may be
attached to the end of the tobacco rod simultaneously with the adhering and/or
folding
of the foldable paper.
In a further embodiment, the method may further comprise, after folding the
overhanging paper, inspecting the folded overhanging paper for defects, and
rejecting
a smoking article found to have a defective folded overhanging paper. The
inspecting
may comprise capturing one or more images of the folded overhanging paper and
comparing the one or more images with one or more stored images of non-
defective
folded overhanging paper. The captured images comprise, for example, an end
view of
the folded overhanging paper and/or a side view of the folded overhanging
paper.
A second aspect of the present invention is directed to apparatus configured
to
perform a method of making a smoking article according to any embodiment of
the
first aspect.
A third aspect 'of the present invention is directed to a smoking article
comprising: a tobacco rod of tobacco wrapped in cigarette paper; and a
foldable paper
adhered to the cigarette paper such that the foldable paper encircles the
tobacco rod
and overhangs the cigarette paper at an end of the tobacco rod that is
intended to be lit,
the overhanging foldable paper folded to substantially cover the tobacco at
the end of
the tobacco rod. The foldable paper may be adhered to the outside of the
cigarette
paper.
The foldable paper may be a porous paper, such as porous plug wrap paper.
The foldable paper may have a porosity greater than 3,000 CU, or greater than
6,000
CU, or greater than 12,000 CU, or greater than 24,000 CU. Further, the
foldable paper
may be embossed with one or more crease lines along which the overhanging
foldable
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paper is folded. The foldable paper encircling the tobacco rod may extend over
only
part of the length of the tobacco rod, or over substantially the whole- length
of the
tobacco rod.
The foldable paper may be shaped along an edge such that the overhanging
foldable paper has an edge profile that gives .a reduced amount of overlapped
paper
after folding compared to a straight edge.
The overhanging foldable paper may be folded with a first fold, a second fold
opposite the first fold, a third fold orthogonal to the first and second
folds, and a fourth
fold opposite the third fold. In an alternative, the overhanging foldable
paper may be
folded with a plurality of folds, each fold overlapping the adjacent fold.
The smoking article may further comprise a filter unit attached to the end of
the tobacco rod opposite to the end intended to be lit.
A fourth aspect of the present invention is directed to apparatus for making a
smoking article comprising: a first sub-apparatus operable to receive a fully
or
partially fabricated smoking article comprising at least a rod of tobacco
wrapped in
cigarette paper and to adhere a foldable paper to the cigarette paper such
that the
foldable paper encircles the tobacco rod and overhangs the cigarette paper at
an end of
the tobacco rod that is intended to be lit; and a second sub-apparatus
operable to
receive a smoking article with an overhanging foldable paper produced by the
first
sub-apparatus and to fold the overhanging foldable paper to substantially
cover the
tobacco at the end of the tobacco rod.
The first sub-apparatus and the second sub-apparatus may be configured
according to
a range of different embodiments. Additionally, the apparatus may further
comprise a
third sub-apparatus operable to receive a smoking article with a folded
overhanging
foldable paper from the second sub-apparatus and to push a pin having a width
less
than the diameter of the smoking article against the folded overhanging
foldable paper
to depress the folded paper and cause it to better maintain its folded
position, and/or to
apply pressure and/or heat to the folded overhanging foldable paper to active
adhesive
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on the overhanging foldable paper and cause it to become adhered in its folded
position. Further, the apparatus may also comprise a fourth sub-apparatus
operable to
attach a filter unit to the end of a tobacco rod of a partially fabricated
smoking article,
opposite to the end intended to be lit. Also, an inspoction system may be
included,
operable to inspect the folded overhanging paper for defects and reject a
smoking
article found to have a defective folded overhanging paper.
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BRIEF DESCRIPTION OF THE DRAWINGS
For a better understanding of the invention and to show how the same may be
carried into effect reference is now made by way of example to the
accompanying
drawings in which:
Figures lA and 1B show cross-sectional side views of the end of a smoking
article provided with a foldable paper for closing the lighting end of the
smoking article,
with the foldable paper respectively in unfolded and folded positions, in
accordance with
an embodiment of the invention;
Figure 2 shows a schematic representation, of a first embodiment of a process
for
applying a foldable paper to a smoking article;
Figures 3A and 3B show schematic. representations of exainples of a second
embodiment of a process for applying a foldable paper to a smoking article;
Figure 4 shows a schematic representation of a first embodiment of apparatus
for folding overhanging foldable paper applied to a smoking article;
Figures 5A-5D show a sequence of end views of a smoking article having an
applied overhanging foldable paper which is successively folded using four
folds;
Figure 6 shows a schematic side representation of a second embodiment of
apparatus for folding overhanging foldable paper applied to a smoking article;
Figure 7 shows a schematic side representation of a third embodiment of
apparatus for folding overhanging foldable paper applied to a smoking article;
Figure 8 shows an end view of a smoking article having an applied foldable
paper folded into an iris-style fold such as by the apparatus of Figure 7;
Figure 9 shows a schematic side representation of a fourth embodiment of
apparatus for folding overhanging foldable paper applied to a smoking article;
Figure 10 shows a schematic side representation of a fifth embodiment of
apparatus for folding overhanging foldable paper applied to a smoking article;
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Figure 11 shows a schematic side representation of a sixth embodiment of
apparatus for folding overhanging foldable paper applied to a smoking article;
Figure 11A shows an end view of a smoking article having an applied foldable
paper folded into a three-way fold, such as by use of the apparatus of Figure
11;
Figure 12 shows a perspective schematic representation of a first embodiment
of apparatus for applying a foldable paper to a smoking article and folding
the paper;
Figures 13A and 13B shows cross-sectional side views of a smoking article
having first and second folds made to its overhanging foldable paper using the
apparatus of Figure 12;
Figure 14 shows a perspective schematic representation of a second
embodiment of apparatus for applying a foldable paper to a smoking article and
folding the paper;
Figure 15 shows a perspective schematic representation of a third embodiment
of apparatus for applying a foldable paper to a smoking article and folding
the paper;
Figures 16A, 16B, 16C and 16D show assorted side and perspective views of a
further embodiment of apparatus for folding overhanging foldable paper applied
to a
smoking article;
Figure 17 shows a schematic side representation of an alternative embodiment
of apparatus for applying a foldable paper to a smoking article and folding
the paper;
Figures 18A, 18B and 18C show end views of smoking articles having applied
foldable papers folded according to three further embodiments;
Figures 19A and 19B show schematic side representations of two
embodiments of apparatus for pressing a pin into previously folded paper of a
smoking
article to improve the closure;
Figure 20 shows a schematic side representation of a smoking article having a
pressing pin applied to its folded paper, such as with the apparatus of
Figures 19A or
19B;
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Figure 21 shows three examples of shaped-edge foldable paper that may be
utilised in embodiments of the present invention;
Figure 22 shows a plan view of a foldable paper with adhesive applied
according to an embodiment of the invention; and
Figure 23 shows a view from above of an example inspection system for
detecting smoking articles with defective folded ends, according to another
embodiment.
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DETAILED DESCRIPTION
The present invention proposes closing the end of a smoking article by
providing an extra portion of paper at the end of the tobacco rod of the
smoking article
that is intended to be lit, so that the paper overhangs the end of the rod,
and then
folding the overhanging paper inwards to cover over the exposed tobacco. A
tobacco
rod comprises a cylinder of tobacco wrapped in cigarette paper, with the end
of the
tobacco substantially flush with the end of the paper. According to the
invention, an
additional piece of foldable paper is stuck with adhesive around the outside
of the
cigarette paper after the tobacco rod is formed, so that the foldable paper
encircles the
tobacco rod, and extends beyond the end of the tobacco rod by an amount that
is
sufficient to substantially enclose the tobacco when the overhanging paper is
folded
inwards.
Figure 1A shows a longitudinal cross-sectional view through the end of a
tobacco rod having an overhang of foldable paper according to an embodiment of
the
invention. The tobacco rod 10 comprises tobacco 12 wrapped in a cigarette
paper 14 in
the conventional manner, with the addition of a portion of foldable paper 16
that is
adhered around the circumference of the end portion of the cigarette paper 14.
A
length 18 of the foldable paper 16 extends beyond the end of the tobacco 12
and the
cigarette paper 14 to form an overhang.
Figure 1B shows the same view of the tobacco rod 10 after folding of the
foldable paper 14. The overhanging part 18 of the foldable paper 14 is folded
inwards
against the end surface of the.tobacco 12 so as to close the end of the
tobacco rod and
cover the tobacco that would otherwise be exposed at the end of the tobacco
rod that is
intended to be lit.
The term "tobacco" as used herein is intended to be understood as including
tobacco material (such as stem, lamina, tobacco dust, cut tobacco and expanded
tobacco), reconstituted tobacco and substitute tobacco materials.
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The foldable paper may be any paper that can conveniently be folded in the
required manner. A piece of regular cigarette paper, the same as the cigarette
paper of
-the tobacco rod, may be used. However, it has been found that a more
satisfactory
result can be achieved if a paper of a lighter weight than cigarette paper is
used. A
lighter paper is thinner and hence more easily folded. Also, a lighter paper
has greater
porosity, which makes it easier for the smoker to draw on the smoking article
when
lighting it, so that ease of lighting is less impaired by the presence of the
folded paper.
For example, porous plug wrap paper, of the type generally used to wrap around
the
acetate tow core of a cigarette filter unit, may be used. This is a thin paper
with a high
porosity, and is also conveniently readily available in the industry due it
being already
used in cigarette manufacture. More generally, paper with a porosity greater
than
3,000 CORESTA units (CU), or greater than 6,000 CU, or greater than 12,000 CU,
or
greater than 24,000 CU is recommended, although papers with other porosity
values
are not excluded.
Figures 1A and 1B show an embodiment in which the foldable paper is
relatively short compared to the overall length of the tobacco rod, so that
the foldable
paper extends only a short distance along the length of the cigarette paper.
For
example, the length of foldable paper that overlaps the cigarette paper may be
substantially equal to the length that overhangs the end of the tobacco rod.
The length
may be selected according to how much paper it is desired to use (a short
length
obviously using less paper and hence being less costly), and how large an area
of
overlap is needed to provide a secure adherence of the foldable paper to the
cigarette
paper. While a short length is economic, long lengths may be used instead, up
to and
including a length of foldable paper that extends over substantially the
entire length of
the tobacco rod. This latter example has the advantage that the end of the
foldable
paper opposite to the folded end can be hidden under a tipping paper used to
join a
filter unit to the tobacco rod, giving a smooth outer surface to the tobacco
rod of the
completed smoking article. This gives an improved aesthetic appearance to the
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smoking article, and also protects the edge of the foldable paper and prevents
it
becoming caught and possible torn during subsequent processing and handling of
the
smoking articl-e.
Yor foldable paper applied over the length of the tobacco rod, it is
convenient
to apply the foldable paper to the tobacco rod before the tobacco rod is
assembled with
a filter unit to form a completed smoking article, so that the edge of the
foldable paper
can be wrapped under the tipping paper as mentioned above. However, for
embodiments using a shorter length of foldable paper, the foldable paper can
be
applied to the tobacco rod at any stage in the fabrication of the smoking
article,
including before or after a filter unit is joined to the tobacco rod. Hence,
methods of
the invention are applicable to both fully and partially fabricated smoking
articles,
where it is merely required that a tobacco rod be provided for adherence of
the
foldable paper to the cigarette paper thereof. If the smoking article is only
partly
fabricated, and comprises a tobacco rod without a filter at the time of
applying the
foldable paper, a filter unit can be added subsequently to form a filter
smoking article.
Alternatively, the smoking article may be intended as a plain cigarette, so
that no filter
is added to the tobacco rod. Consequently, in the following description and
appended
claims, the term "smoking article" is intended to cover both substantially
completed
smoking articles, and partially completed smoking articles (which may comprise
a
tobacco rod only). Furthermore, if the smoking article is only partly
fabricated, a filter
unit can be added simultaneously with the application and folding of the
foldable
paper. This combines two handling stages into one and hence reduces production
time
for the smoking articles. Simultaneous processing in this way is facilitated
by the fact
that the application and folding of the foldable paper can be carried out
using
conventional smoking article manufacturing apparatus such as is employed for
filter
attachment with only small modifications, so that the additional processes can
be
readily integrated into existing production lines.
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According to one embodiment, it is proposed that the foldable paper be
supplied as individual glued pieces that are applied to individual smoking
articles, and
then wrapped around the tobacco rods so that the giue adheres to the cigarette
paper
and holds the foldable paper in place.
A convenient way to handle the smoking articles during this process is to
carry
them on the surface of one or more rotating drums, as is commonly done in
existing
smoking article manufacturing processes. A rotatable drum, mounted on a
spindle and
driven by a motor at an appropriate speed of rotation to synchronise with
related
machinery, has a plurality of longitudinal grooves or flutes in its outer
surface around
its circumference, each flute arranged parallel to the rotational axis of the
drum and
dimensioned to accommodate a smoking article. Each flute has one or more holes
in
its surface that are connected to a vacuum pump so that a smoking article can
be held
in the flute by suction. The smoking art.icles can thereby be received onto a
drum or
discharged from a drum, including being passed from one drum to an adjacent
drum,
by turning the vacuum on and off at the appropriate times. One or more drums
can be
used to carry smoking articles past a variety of processing devices that
perform
different manufacturing steps on the smoking articles.
Figure 2 shows a schematic representation of the use of rotating drums for
applying a foldable paper to a smoking article, shown as a view along the axes
of
rotation of the drums. In this example, the foldable paper is provided as a
pre-wound
roll- 20 of appropriate paper 22, such as porous plug wrap, the paper on the
roll 20
having a width that is the required length of the foldable paper when it is
wrapped
around a tobacco rod (i.e. the length of the overhang plus the length of the
portion that
extends over the cigarette paper along all or part of the tobacco rod). The
paper 22 is
unwound from the roll 20 and passed through a pair of embossing rollers 23,
which
emboss the paper with one or more crease lines corresponding to the lines
along which
the paper is to be folded to close the end of the smoking article. The crease
lines
facilitate the later folding of the foldable paper, but need not be included,
so the
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embossing rollers 23 may be absent from the apparatus. Alternatively, the
foldable
paper 22 may be provided pre-embossed on the roll 20. The foldable paper then
travels
past a glue applying device 26 which applies adhesive 24 to one side of the
paper 22.
Any suitable glue applying device may-be used, such as a roller system or a
glue spray
unit. After gluing, the paper 22 from the roll 20 is then cut to the correct
length using a
cutting device 28. The correct length is a length sufficient to completely
encircle the
smoking article, with optionally an overlapping edge. In this example, the
cutting
device 28 is a vacuum cutting drum 28. - This is a drum with a plurality of
cutting
blades 29 spaced around its circumference. Rotation of the drum 28 brings the
blades
lo in turn into contact with the paper 22, and each blade cuts off a correct
length 30 of the
paper 22. The surface of the drum 28 is also provided with suction holes
through
which a vacuum is applied to hold the individual, foldable papers 30 against
the drum
28 as it rotates.
The foldable paper 30, now glued and of the necessary size, is carried by the
rotation of the vacuum cutting drum 28 into a position in which its leading
edge
extends into the path of a smoking article 32 being carried on the surface of
a first
rotating drum 34. The smoking article 32 is delivered to the drum 34 from a
hopper or
an adjacent drum, and taken up by a flute on the surface of the drum 34. As
the drum
34 rotates, the smoking article 32 'comes into contact with the leading edge
of the
foldable paper 30, and the foldable paper 30 sticks to the cigarette paper of
the
smoking article 32 because of the previously applied adhesive. This sticking
action
pulls the foldable paper 30 off the vacuum cutting drum 28, so that the
foldable paper
is now carried by the smoking article 32. The vacuum cutting drum 28 and the
rotating
drum 34 are positioned relative to one another along the longitudinal
direction of the
smoking article 32 so as to give the required length of overhang when the
paper 30 is
stuck to the smoking article 32.
The first rotating drum 34 rotates further, carrying the smoking article 32
and
attached foldable paper 30 with it. A second rotating drum 36 is positioned
adjacent to
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the first drum 34 and rotating in an opposite direction about a parallel axis.
The
rotation of the drums 34, 36 brings the smoking article 32 into a flute on the
second
drum 36, and appropriate switching of the vacuum-suction in the two flutes
transfers to
the smoking article to the second drum 36.
A rolling plate 38 is positioned adjacent to the second drum 36. The rolling
plate 38 is a static plate having a curved surface 40 with a profile that
matches the
outer circumference of the drum 36. The plate 38 is located such that the
curved
surface 40 is spaced f-rom the surface of the drum 36 by slightly less than
the amount
by which the smoking article 32 protrudes from the surface of the drum 36. As
the
drum 36 rotates it brings the smoking article 32 into the space between the
drum 36
and the surface 40 of the rolling plate 38, but in an interference fit owing
to the
spacing. This interference fit causes the smoking article 32 to rotate about
its own
longitudinal axis within the flute (in an opposite direction to that of the
rotation of the
drum) as the smoking article is carried through the space by the drum 36, so
that the
smoking article 32 in effect rolls over the curved surface 40 of the rolling
plate 38.
This rolling also causes the smoking article 32 to roll over its attached
foldable paper
30, so that the foldable paper 30 adheres right around the circumference of
the tobacco
rod and forms a tube that extends beyond the end of the tobacco rod. When the
smoking article 32 is carried past the,rolling plate 38, it is ready for
folding of the
overhanging foldable paper.
Application of the foldable paper according to the embodiment of Figure 2 can
be used for any length of foldable paper, and for partially and fully
assembled
smoking articles.
A potential problem that may arise from use of a rolling plate to apply the
foldable paper is that of ends fall-out, in which tobacco pieces at the open
end of a
tobacco rod can become loosened and may subsequently be lost. In the present
case,
this can be caused by the pressure exerted on the end of the smoking article
by the
rolling plate. This can be addressed by appropriate configuration of the
rolling plate
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and rotating drum combination to reduce the pressure applied to the smoking
article,
and/or to shift the position(s) along the length of the smoking article at
which pressure
is applied.
An alternative approach is pre-gluing of the cigarette paper before
fabrication
of the smoking article. One or more lines or dots of adhesive can be applied
to the
inside surface of the cigarette paper before it is wrapped around the tobacco,
the lines
or dots positioned to coincide with the end of each smoking article. The end
part of the
tobacco is thereby secured within the cigarette paper, and is less likely to
be loosened
during application of the foldable paper.
Figure 3A shows a schematic representation of a technique for applying a
foldable paper that extends over the full length of the tobacco rod of the
smoking
article. In this case, a continuous length of foldable paper 42 is fed from a
roll (not
shown), and arranged in the horizontal direction. The paper has a width which
is at
least the circumference of the smoking article so that it can completely
encircle the
tobacco rod when wrapped around the smoking article. Possibly the width of the
foldable paper is greater than the circumference of the smoking article, so
that there is
an overlap when the foldable paper is wrapped around the tobacco rod, which
may
assist with gluing, for example. Adhesive is applied to the upper surface of
the
foldable paper, at least along one edge. The amount and position of the
adhesive can
be selected as desired, depending on how much of the surface of the foldable
paper it
is desired to stick to the cigarette paper, and whether an overlap is used.
A continuous stream of smoking articles 44 is delivered onto the upper surface
of the foldable paper 42, as indicated in section A of the Figure. The smoking
articles
do not have filters, and may comprise only a tobacco rod in the form of
tobacco 46
wrapped in cigarette paper 48. The smoking articles 44 are arranged end to end
in a
line, and positioned along the length of the foldable paper 42. However, the
smoking
articles are spaced apart along the line by a distance d that is equal to the
desired
length of the overhang of the foldable paper.
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The smoking articles 44 and the foldable paper 42 are moved along together,
as shown by the arrow in the Figure, and fed into a tube (not shown) having an
inner
diameter substantially the same as the diameter of the smoking articles 44. As
shown
in section B of the Figure, the wall of the tube guides the foldable paper 42
around the
smoking articles 44, and the adhesive causes the foldabla paper 42 to stick in
place so
as to encircle the -cigarette papers 48 of the smoking article 44. This
results in a
continuous tube of foldable paper 42 with smoking articles 44 spaced apart in
a line
inside the tube.
Finally, the continuous tube is cut into sections, as shown in section C of
the
Figure. A cutting device 50, such as a blade, is arranged to cut through the
tube of
foldable paper 42 at intervals corresponding to the length of the smoking
articles 44
plus the foldable paper overhang. The cuts are positioned to be flush with one
end of
each tobacco rod. This divides the continuous tube into individual smoking
articles 44
each comprising a tobacco rod with a foldable paper wrapped around it that
extends
over the whole length of the tobacco rod and further extends beyond one end of
the
tobacco rod to give the desired overhang 18 for folding.
Alternatively, the stream of smoking articles 44 may be delivered onto the
foldable paper 42 in pairs, with the two article in each pair being
substantially
touching or abutting at their adjacent ends, and the pairs being spaced apart
by a
distance 2d, which is equal to twice the desired length of the overhang of
foldable
paper. Once wrapped in the continuous tube of foldable paper 42, the smoking
articles
44 are then separated by the tube being cut at the midpoint of each space
between
pairs of smoking articles, and also at the point where the articles 44 in each
pair abut.
Figure 3B shows a schematic representation of this arrangement, using the
same reference numerals as Figure 3A. A second cutting blade 50' is shown in
phantom to indicate, in conjunction with the first cutting blade 50, the two
cutting
points relative to each pair of smoking articles 44. In reality, the cuts can
all be
effected by a single cutting device if preferred.
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An advantage of these methods of applying the foldable paper to the smoking
articles is that they can be readily adapted from known apparatus for making
cigarettes
with a double-wrapped tobacco rod. Such cigarettes have an outer layer of
paper
overlying the cigarette paper, and the tobacco rods for these cigarettes can
be made by
delivering a continuous stream of single-wrapped tobacco rods, arranged end to
end
with no spaces, onto a glued length- of outer wrap which is then wrapped
around the
tobacco rods. The resulting continuous tube is then cut at each break between
the
single-wrapped rods. By adjusting the supply of tobacco rods so as to give the
necessary spacing between the rods, and using a cutting device that can cut
through
the foldable paper tube without crushing or deforming the overhang, the
embodiments
of the present invention as shown in Figures 3A and 3B may be implemented.
The present invention further proposes a number of techniques for folding the
overhanging foldable paper so as to cover the exposed end of the tobacco rod.
It is
proposed that these techniques be implemented by carrying the smoking
articles,
already provided with overhangs of foldable paper, on one or more rotating
drums like
those described above with regard to Figure 2 that bring the foldable paper
overhangs
into contact with one or more folding devices that engage the paper to push it
inwards
over the tobacco. Different devices can be employed to achieve different
folding
effects, with various numbers and arrangements of folds.
Figure 4 shows a schematic view of a first example of a folding arrangement,
comprising four folding devices arranged next to a rotating drum. The drum 52
carries
smoking articles 54 in vacuum flutes on its outer surface, as described
before, the
smoking articles having been delivered thereto from a hopper or another
rotating
drum. As the drum rotates, it carries the smoking articles past the four
folding devices
in turn. Each folding device comprises a substantially flat surface arranged
orthogonal
to the axis of rotation of the drum 52 and hence also to the longitudinal axes
of the
smoking articles 54. Further, the surfaces of the folding devices are located
in a plane
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that is substantially flush with the end surfaces of the tobacco in the
tobacco rods of
the smoking articles 54 as they are carried by the drum 52.
The first folding device 56 comprises a reciprocating tucker in the form of
surface having a width that is less than the diameter of the smoking articles.
It has a
fixed location with respect to the drum 52, but which can move back and forth
along a
direction perpendicular to its width which is also substantially parallel to a
tangent of
the drum 52, as shown by the arrow in the Figure. In a starting position, the
reciprocating tucker occupies a position retracted from the drum which allows
a
smoking article to pass by untouched. When a smoking article 54 reaches the
position
54a, past the reciprocating tucker 56, the tucker moves forward so that its
surface
slides partially over the end of the tobacco rod on the trailing side, pushing
part of the
overhanging foldable paper before it to that the paper is pushed inwards and
over the
tobacco. The tucker 56 is then retracted before it reaches the foldable paper
overhanging the opposite side of the smoking article 54. A first fold is
thereby formed.
The second folding device 58 comprises a static tucker, again in the form of a
surface having a width less than the diameter of the smoking article. It
occupies a
fixed position with respect to the drum 52, arranged with its width
substantially
perpendicular to a further tangent of the drum 52. It is located such that the
smoking
article, carried by the rotating drum and already having a first fold, passes
behind the
tucker 58 (with respect to the viewing direction of Figure 4) with the surface
of the
tobacco flush with the surface of the tucker 58. The front edge of the tucker
pushes
against the overhanging foldable paper as the smoking article moves into the
tucker,
and folds it over against the tobacco, to create a second fold opposite the
first fold.
The presence of the first fold on the trailing side of the smoking article
means that the
smoking article is free to pass under the static tucker once the leading side
of the paper
has been folded as the second fold. The positions of the first folding device
56 and the
second folding device 58, and the movement of the first folding device
relative to the
speed of the drum 52, are arranged so that the first tucker 56 makes its fold
just prior
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to the smoking article starting to be folded by the second tucker 58. Upon
completion
of the second fold, the first tucker 56 retracts to allow the next smoking
article to pass
by prior to the first tucker moving forward again to create a first fold on
the trailing
side.
The third folding device 60 comprises a static plough folder. This has a
surface
with a tapering profile, arranged to offer an edge to the incoming leading
side of the
smoking article that begins at one side of the smoking article end (with
respect to the
direction of travel of the smoking article) and converges towards the midline
of the
smoking article end as the travel path of the smoking article proceeds. Thus,
as the
smoking article is carried past the folder, the edge engages the overhanging
paper at
the side of the smoking article, and gradually pushes it inwards and over
against the
end of the tobacco rod as this end passes against the surface of the folder.
This creates
a third fold that is substantially at right angles to the first and second
folds.
Finally, the fourth folding device 62 comprise a further static plough folder.
This has the same structure as but the opposite configuration to the third
folding
device 60, so that the converging edge is positioned on the other side of the
smoking
article. Therefore, travel of the smoking article past this plough folder
engages the
opposite overhanging paper, and folds it inwards against the end of the
tobacco rod to
create a fourth fold opposite to the third fold. For reasons of space, the
fourth folding
device 62 will probably need to be positioned downstream from the third
folding
device 60, so that each of the surfaces can extend sufficiently far across the
end of the
tobacco rod to completely fold over the overhanging foldable paper.
The folding devices of Figure 4 create an envelope fold comprising two
opposite folds overlaid by two further opposite folds that are orthogonal to
the first
opposite folds.
Figures 5A-5D show schematic representations of the end view of a smoking
article being provided with an envelope fold, such as by use of the apparatus
of Figure
4. A first fold 64 is followed by a second fold 66 on the opposite side of the
smoking
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article, a third fold 68 at right angles to the first and second folds, and a
fourth fold 70
opposite to the third fold. The exposed tobacco 72 at the end of the tobacco
rod is
gradually covered over.
Figure 6 shows a schematic representation of a further example of folding
apparatus. A rotating drum 74 that carries smoking articles 54 in vacuum
flutes on its
surface, as before, is used in conjunction with a static rolling plate 76,
like the rolling
plate 38 described with reference to Figure 2. As before, the interference fit
of the
smoking article 54 between the surface of the rotating drum 74 and the curved
surface
of the rolling plate 76 causes the smoking article 54 to rotate about its own
to longitudinal axis so that it rolls over the surface of the plate 76. In
this example, the
rolling plate 76 is provided with a plough folder 78. The plough folder 78 is
fixed to
the rolling plate 76 and comprises a surface extending from the curved surface
of the
rolling plate 76 that is in the plane of the ends of the tobacco rods of the
smoking
articles 54 so that the ends of the rods pass against the surface as the
smoking articles
54 roll over the rolling plate 76. The surface of the plough folder 78 has an
edge that
begins at the surface of the rolling plate, and converges towards the surface
of the
drum, so that the far end of the plough folder extends at least halfway across
the space
between the rolling plate 76 and the drum 74. When a smoking article is
carried onto
the rolling plate 76 by rotation of the drum 74, the front end of the plough
folder 78
engages with the overhanging foldable paper at the end of the tobacco rod, and
gradually pushes it over and inwards against the end surface of the tobacco.
As the
smoking article 54 rolls over the rolling plate 79, the edge of the plough
folder 78
continually engages with a new part of the overhanging foldable paper and
folds it
over against the tobacco. As the smoking article 54 progresses across the
plough
folder 78, the converging edge gradually extends across more of the end of the
smoking article 54, thus folding the overhanging paper over along its whole
length. In
this manner, a continuous fold is formed all around the circumference of the
tobacco
rod and the overhanging paper is brought flat against the end of the tobacco
in the
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tobacco rod. When the smoking article 54 emerges from the end of the plough
folder
78, its end is completely covered by folded paper, provided that -the original
overhang
was of sufficient length.
Figure 7 shows a schematic representation of a further example of a folding
5- apparatus. This is similar to that of Figure 6, in that it utilises a
rotating druin 74 to roll
smoking articles 54 over the surface of a static rolling plate 76. In this
example,
however, the plough folder is replaced with a series of teeth 80. Like the
plough
folder, the teeth 80 extend inwardly from the surface of the rolling plate 76
and have
surfaces in a plane level with the end of the tobacco in the tobacco rods of
the smoking
articles 54. Each tooth 80 has an edge that begins on the surface of the
rolling plate 76
and converges towards the surface of the drum, so that the far end of each
tooth 80
extends at least half way across the space between the rolling plate 76 and
the drum
74. Thus, each tooth 80 may be thought of as an individual plough folder.
However,
the length of each tooth in the direction of travel of the smoking articles is
less than
the circumference of the smoking articles, so each tooth 80 can only fold over
a part of
the overhanging foldable paper. The next tooth 80 engages the overhang where
the
previous tooth has stopped folding, and makes a new and separate fold that
overlaps
the previous fold. Each tooth 80 makes a separate fold which overlaps the
preceding
fold. Thus, there must be enough teeth to fold over all of the overhanging
paper, so the
total length of the teeth must be at least the circumference of the smoking
article 54.
This gives an iris-style fold, comprising the same number of folds as there
are teeth 80
on the rolling plate 76.
Figure 8 shows a schematic end view of a smoking article having its end
closed with an iris fold. The five overlapping folds have been formed in the
order a to
e, for example using the five teeth 80 on the rolling plate 76 shown in Figure
7.
Figure 9 shows a schematic representation of a yet further example of a
folding
apparatus that uses a rotating drum 74 and a static rolling plate 76. In this
example,
each vacuum flute for carrying a smoking article 54 has an associated cam
folder 82.
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For, each flute, the cam folder 82 comprises a cam which is rotatably mounted
on the
end face of the drum 74 in line with the flute such that the cam provides a
surface that
extends -beyond the edge of the end face of the drum, over the smoking article
54 in
the flute, the surface being flush with the end of the tobacco rod of the
smoking article
54. The axis of rotation of the cam is parallel to that of the drum 74, and,
being a cam,
the surface has an edge which is eccentric with respect to the axis of
rotation. Thus, as
the cam rotates, the edge of the surface gradually,extends further and further
over the
end of the tobacco rod. The maximum extent should be at least half-way across
the
width of the smoking article.
When a smoking article 54 enters a flute on the drum 74, the associated cam is
in a position in which the cam surface does not protrude beyond the edge of
drum 74.
When the smoking article reaches the rolling plate 76, the cam folder is
switched on,
and the cam surface begins to rotate. As the edge begins to protrude past the
edge of
the drum 74, the edge engages with the overhanging foldable paper and pushes
it over
against the end of the tobacco in the tobacco rod. At the same time, the
smoking
article 54 is rolling over the rolling plate 76, so that as the cam edge
extends further
over the end of the tobacco rod, a new part of the overhang is brought into
engagement
with the cam edge, to be pushed inwards over the tobacco. The cam rotation is
timed
such that as the smoking article 54 rotates once across the rolling plate 76,
the cam
also rotates once so that the edge swings out over the end of the tobacco rod,
and then
gradually recedes as the eccentricity of the cam moves closer to the rotation
axis
again. These movements combine to produce a continuous fold in the overhanging
foldable paper, all around the circumference of the smoking article. The
rotating cam
works in a similar way to the smooth-edged plough folder of Figure 6, by
providing a
tapering edge that gradually extends further and further across the end
surface of the
tobacco rod as the smoking article rolls around, to produce a single
continuous fold.
The folding effect of the tooth-style folder of Figure 7 may also be
replicated
using cam folders. This can be achieved by providing cams with stepped edges
instead
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of the smooth profile shown in Figure 9. Each step in the edge produces a
separate
fold of just part of the overhanging foldable paper, with successive folds
overlapping
to produce a final iris fold.
Figure 10 shows a schematic representation of a still further folding
apparatus
that uses a rotating drum 74 in combination with a rolling plate 76. In this
example,
the rolling plate 76 operates in conjunction with a rotating threaded screw 84
to
engage and fold the overhanging paper. The threaded screw 84 i-s driven by
motor 86
and arranged with its longitudinal_axis, and hence also its axis of rotation,
substantially
orthogonal to the axis of rotation of the drum 74 and the longitudinal axes of
the
smoking articles 54 carried by the drum. The threaded screw 84 is further
positioned
so that it extends largely along the extent of the rolling surface ofthe
rolling plate, and
with the threaded surface in the same plane as the ends of the tobacco rods of
the
carried smoking articles. In this way, the threaded surface forms a surface
flush with
the ends of the tobacco rods over which the tobacco surface can be moved to
fold over
the overhanging paper, as with the flush surfaces in the previous embodiments.
To
achieve folding, the threaded screw 84 is rotated at the same time as the
smoking
article 54 rolls over the surface of the rolling plate 76. The threads of the
screw hence
come into contact with successive parts of the overhanging foldable paper,
engage
therewith, and fold each part inwards against the end of the tobacco rod. By
matching
the speed of rotation of the threaded screw to the rolling speed of the
smoking article,
or setting the speeds to be a ratio, the folds can be made neatly adjacent and
overlapping to form a tidy iris fold. The pitch of the screw thread determines
the
number of folds.
Figure 11 shows another example of a folding apparatus in accordance with the
invention that uses a rotating drum 74 to carry smoking articles 54 past three
folding
devices to create three folds. Two of the folding devices are a pair of
rotating folders
88 which have a fixed location with respect to the drum 74, and are arranged
side by
side substantially along a radius of the drum but beyond the edge of the drum
74, to
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provide two surfaces flush with the ends of the tobacco rods of the smoking
articles_
54. The surfaces rotate about axes parallel to the rotation axis of the drum,
and have
edges shaped such that the rotation brings the surfaces into and out of the
path of the
smoking articles 54 as the drum rotates. For example, the surfaces may be
cams, so
that the eccentricity of the cam rotation gives a surface that in some
positions extends
over part of the end of a smoking article, and in some positions does not,
because the
edge is closer to the axis of rotation of the cam. Alternatively, the surfaces
may be
centrally mounted circular surfaces with a missing sector, such as a quarter,
as shown
in the Figure. Thus, in some rotational positions, the surface extends
partially over the
end of the tobacco rod, and in other positions, the missing sector coincides
with the
tobacco rod so that the surface does not extend over the end of the tobacco
rod. The
two rotating surfaces of the rotating folders are arranged to rotate in
opposite
directions, and in either of the above examples of surface shape, the effect
is to
provide two surfaces with leading edges that engage with adjacent parts of the
overhanging foldable paper as the surfaces rotate, further rotation of the
surfaces
causing the surfaces to sweep over the end of the tobacco rod and fold over
the
foldable paper to form first and second folds. The folds are substantially
along the two
sides of the smoking article with respect its direction of travel, but also
adjacent in a
substantially V-shaped formation.
The rotational positions, directions of rotation and speeds of rotation of the
two
rotating folders 88 are chosen such that a smoking article can initially pass
between
them with no folding (the surfaces are in positions in which they do not
extend over
the ends of the tobacco rods). At a particular point, when the smoking article
54 is in
range of the folding surfaces when they are rotated into position
(approximately 54a in
Figure 11), the folders 88 rotate, the leading edges of the surfaces engage
with the rear
of the overhanging foldable paper, and the surfaces sweep forwards across the
end of
the tobacco rod to fold the two sides of the overhanging paper flat against
the tobacco.
The surfaces need to be rotating faster than the drum to achieve this so that
the
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smoking article 54 does not move out of range of the rotating folders 88
before folding
is complete. Alternatively, the rotating drum 74 may be halted while the
rotating
folders 88 rotate.
The two rotating folders 88 can be arranged as a pair, as in Figure 11, so
that
the first and second folds are formed simultaneously. This is advantageous if
the
rotating rirum is halted for folding, as less time is needed to make these two
folds.
However, the same folding effect can be achieved by positioning the rotating
folders
88 at different points around the drum 74.
The apparatus of Figure 11 further comprises a third folder 90, which is a
static
tucker like the second folding device 58 in Figure 4. The third folder
provides a
surface fixed relative to the drum, and as with previously described surfaces,
arranged
in the same plane as the end of the tobacco in the tobacco rods. As the
smoking article
having first and second folds approaches the third folder 90, the edge of the
surface
engages the leading edge of the overhanging foldable paper, and folds it flat
against
the tobacco as the smoking article passes under the surface of the folder 90
to create a
third fold. Alternatively, a further rotating folder may be used to make the
third fold,
having a surface with a suitably shaped edge to sweep over the appropriate
part of the
overhanging foldable paper as the smoking article is carried past.
Figure 1 lA shows an end view of a smoking article with its end closed with a
three-way fold, such as may be formed with the apparatus of Figure 11, for
example.
Figure 12 shows a simplified schematic perspective view of apparatus
according to an embodiment of the invention that uses a series of five
rotating drums
to apply a foldable paper to the end of the smoking article, and then fold the
overhanging foldable paper over in a four-way envelope fold.
The rotating drums 100, 102, 104, 106, 108 are represented with dotted lines
only, for the sake of clarity. The drums are arranged in sequence from right
to left and
positioned adjacent to one another so that the smoking articles 54 carried
thereon can
be transferred from a flute on one drum to a flute on the next drum by
appropriately
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timed switching of .the vacuum suction. The first and second drums 100 and 102
are
used to apply a foldable paper 110 to the end of each smoking article 54 i-n
the same
way as described with reference to Figure 2. The first drum 100 carries the
smoking
articles 54 past a supply _of glued foldable papers 110 so that each smoking
article 54
picks up a foldable paper 110. The second drum 102 carries the smoking
articles 54
over a rolling plate (not shown) so that the resulting rolling motion causes
the foldable
paper 110 to be wrapped around the tobacco rod and stuck to the cigarette
paper
(smoking article 54b).
After application of the foldable paper 110, the smoking article is
transferred
from its flute on the second drum 102 to a flute on the third drum 104
(smoking article
54c). Each flute on the third drum is provided with a flute former, which is a
protrusion extending outwardly from the surface of the flute that pushes
against the
overhanging foldable paper 110 as the smoking article enters the flute, and
hence folds
the foldable paper 110 flush against the end of the tobacco rod as the smoking
article
moves fully into its seat within the flute, if the smoking article is
appropriately
positioned relative to the protrusion.
Figure 13A illustrates a side view of the smoking article 54c as it is
beginning
to enter a flute 112 on the third drum 104 (the smoking article 54c moving
into the
flute 112 in the direction of the arrow). The protrusion 114 pushes the
overhanging
foldable paper 110 over into a folded position as the end of the tobacco rod
116 slides
under the protrusion 114. This creates a first fold in the foldable paper 110.
The smoking article 54 having a first fold in its foldable paper 110 is then
transferred to a flute in the fourth drum 106. The flutes on the fourth drum
106 are
provided with flute formers or protrusions which act to create a second fold
in the
foldable paper 110 as the smoking article 54d enters the flute, in the same
manner as
for the third drum 104. Given that the first fold is made at the side of the
smoking
article 54 closest to the centre of the third drum 104 as the smoking article
54 enters
the flute on the third drum 104, the second fold is made opposite to the first
fold
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because the side of the smoking article 54 furthest from the centre of the
third drum
104 is the side of the smoking article 54 that enters the flute on the fourth
drum 106.
Figure 13B shows a side view of the smoking article 54d as it is beginning to
enter a flute 112 on the fourth drum 106. The protrusion 114 pushes the
overhanging
foldable paper 110 over into a folded position as the end of the tobacco rod
116 slides
under the protrusion 114, to create a second fold opposite the first fold.
The fourth drum 106 is also provided with a static rolling plate (not shown)
that operates to rotate the smoking articles by approximately 90 within the
flutes
(smoking article 54e). This action brings the smoking articles in a position
in which
the as yet unfolded parts of the overhanging foldable paper 110 are arranged
along the
radius of the fourth drum 106. To facilitate the rotation with the rolling
plate, it may
be necessary to arrange the protrusions 114 on the fourth drum 106 to be
retractable
into a position where they do not extend into the flutes and hence do not
become
caught on the unfolded foldable paper as the smoking articles 54 turn within
the flutes.
More generally, the protrusions on both the third drum and the fourth drum
may be movable between an extended position in which they act to fold the
overlapping paper as the smoking article enters the flute, and a retracted
position in
which they do not protrude into the flute and hence do not impede future
motion of the
smoking article, including rotation within the flute and transfer from the
flute.
Movement between the two positions may be timed to synchronise with the
rotation of
the various drums, to achieve a smooth and continuous passage -of -the smoking
articles
through the drum sequence. Alternatively, the protrusions on one or both of
the third
and fourth drums may be static.
Finally, the smoking articles 54 are transferred to a fifth drum 108, which
carries the smoking articles 54f past a pair of plough folders 118 which
operate as the
plough folders described with regard to Figure 4 to fold over the two
remaining
overhanging parts of the foldable paper 110 to create third and fourth folds
opposite
one another and orthogonal to the first and second folds.
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Figure 14 shows a simplified schematic perspective view of apparatus
according to a further embodiment of the invention that also uses a series of
five
rotating drums to apply a foldable paper to the end of the smoking article,
and then
fold the overhanging foldable paper over in a.four-way envelope fold. In this
example,
the first, second, third and fourth drums 100, 102, 104, 106 operate in the
same way as
for the embodiment of Figure 12 to apply a foldable paper 110 to each smoking
article
54 and to create first and second folds in the overhanging foldable paper 110
using
protrusions in the flutes of the third and fourth drums 104, 106. Again, the
fourth drum
106 has a fixed rolling plate that rotates the smoking articles by 90' before
they are
transferred to the fifth drum 108.
The embodiment of Figure 14 differs from that of Figure 12 in that the plough
folders 118 of Figure 12 are replaced by a pair of reciprocating folders 120.
These
folders are two folding surfaces in the plane of the end of the tobacco rods
carried by
the smoking article 54 on the fifth drum 108 that can pivot between a first
position
where they are both out of the path of the smoking articles 54 so that a
smoking article
can pass between them with no contact to the overhanging foldable paper, and a
second position in which they lie in the path of the smoking articles 54 so
that the ends
of the tobacco rods pass flush with the folding surfaces. As the folders 120
move from
the first position to the second position, the edges of the folding surfaces
sweep across
the end of the tobacco rod, pushing the two remaining parts of the overhanging
foldable paper inwards to create the third and fourth folds.
Figure 15 shows a simplified schematic perspective view of apparatus
according to a yet further embodiment of the invention that uses a series of
six rotating
drums to apply a foldable paper to the end of the smoking article and then
fold the
overhanging foldable paper over into a four-way envelope fold. Once again, the
first,
second, third and fourth drums 100, 102, 104, 106 operate in the same way as
for the
embodiment of Figure 12 to apply a foldable paper 110 to each smoking article
54 and
to create first and second folds in the overhanging foldable paper 100 using
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protrusions in the flutes of the third and fourth drums 104, 106. However, in
this
example, there is no rolling plate associated with the fourth drum 106, so the
smoking
articles are not rotated in their flutes before entering the flutes of the
fifth drum 122.
Each flute of the fifth drum 122 is provided with a shaped static folder 126
that
is attached to the end surface of the drum 122 (only one shown). As with
previously
described folders, each static folder offers a surface in the plane of the end
of the
tobacco rods of the smoking articles held on the associated drum against which
the
end of the tobacco rod slides with the result that part of the overhanging
foldable paper
is pushed over and folded flat against the end of the tobacco rod. In the
present
example, after the first and second folds are formed, the two remaining
overhanging
parts of the foldable paper 110 are located at the side of the smoking
articles with
respect to the direction in which the smoking articles enter the flutes of the
fifth drum
122 (because of the lack of a rolling plate to turn smoking articles on the
fourth drum
106). Hence, the static folders 126 are located to overhang a side of each
flute, to fold
in the corresponding side of the overhanging foldable paper 110. The static
folders
126 are shaped so that they present an edge to the incoming smoking articles
that
begins towards the outside of the smoking article and converges towards the
centre of
the end of the smoking article as the smoking article enters the flute. Hence
the static
folders operate in a similar manner to plough folders, and fold in a part of
the
overhanging foldable paper 110 that is at the edge of the smoking article with
respect
to the forward direction of movement of the smoking article as the smoking
article
enters and moves into the flute. A third fold is thereby created that is
orthogonal to the
first and second folds.
Similarly, the sixth drum 124 also has static folders 128 associated with each
flute. The static folders 128 are located with respect to the flutes so as to
fold over the
remaining part of the overhanging foldable paper, thus creating a fourth fold
opposite
the third fold.
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In the embodiments of Figures 14 and 15, the protrusions on the third and
fourth drums may be static or movable, as described with reference to Figure
13.
Figure 16A shows a cross-sectional side view of a further embodiment of
apparatus for folding the foldable paper, using pincers. The apparatus 150
comprises a
shaft 152 by which the apparatus can be mounted on a rotatable drum, and a
pincer
mechanism 154 mounted on one end of the shaft 150. The pincer mechanism 154 is
mounted so that it can move along the direction defined by the length of the
shaft 150.
The pincer mechanism 154.comprises a cylindrical housing 156 sized to receive
the
end of a smoking article, and a pair of pincers 158 mounted on opposite sides
of the
housing 156. Each pincer 158 is formed from an L-shaped member that is
pivotably
mounted on the housing 156 at the angle between the two arms of the L-shaped
member. Each pincer 158 is mounted such that one arm 160 of the L-shaped
member
forms a pincer arm that extends generally longitudinally and terminates in an
inwardly
facing jaw 162. The other arm 164 of the L-shaped member forms a connecting
arm
that extends generally outwardly and terminates in a connection poiint 166 by
which
the arm 164 is connected to one end of a spring 168 which extends
longitudinally. The
other end of the spring 168 is connected to a slidable collar 170 that
encircles the
housing 156 and can slide longitudinally over part of the housing 156. The
slidable
collar 170 generally occupies a retracted position (as shown in Figure 16A) in
which it
is drawn back away from the pincer jaws 162. In this position, the tension of
the
springs 168 pulls on the connecting arms 164 of the pincers 158, turning the
pincers
about the pivotal mounting so that the jaws 162 are open.
Figure 16B shows a plurality of pincer apparatus 150 mounted on a rotatable
drum 172. Each apparatus 150 is longitudinally aligned with a vacuum flute 174
in the
drum 172 and positioned at the end of the vacuum flute 1=74 so that the
apparatus 150
can operate on a smoking article held in the vacuum flute 174. In use,
therefore,
multiple smoking articles are transferred to the vacuum flutes 174 of the drum
172 so
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that folding -of the foldable paper can be carried out on all the smoking
articles
together.
Figure 16C shows a side view of the apparatus 150 in use in a first step of'
folding. After a smoking article 54 is transferred to a vacuum flute on the
rotating
drum, the pincer mechanism 154 moves forward towards the smoking article 54,
as
shown by the arrow, until the overhanging foldable paper 110 is received
within the
jaws 162 of the pincers 158. The edge of the jaws 162 is aligned with the end
of the
tobacco in the smoking article 54.
Figure 16D shows a side view of the apparatus 150 in use in a second step of
folding. After alignment of the smoking article 54 and the pincers 158 as
shown in
Figure 16C, the slidable collar 170 moves forward over the outside of the
housing 156,
towards the pincers 158. This releases the tension in the springs 168 so that
the pincers
158 are free to pivot about the pivotal mountings. At the same time, the edge
of the
slidable collar 170 comes into contact with the connecting arms 164 of the
pincers
158, and pushes against them, which has the effect of pivoting the pincers 158
so that
the jaws 162 close towards each other, as indicated in Figure 16D. The jaws
162 push
opposite sides of the overhanging foldable paper 110 inwards over the tobacco
in the
smoking article 54, thereby creating opposite first and second folds of an
envelope
fold. After folding, the slidable collar 170 retracts, allowing the springs
168 to pull the
jaws 158 open. Then the pincer mechanism 154 also retracts away from the
smoking
article to release it for further processing.
After this folding stage, the smoking articles can be transferred from the
rotatable drum to apparatus for forming the third and fourth folds. For
example, a
second rotating drum having further pincer apparatus 150 can be provided, with
an
intermediate stage, such as a rolling plate, for rotating the smoking articles
so that they
are transferred onto the second drum with the overhanging foldable paper in
the
correct orientation for folding with the pincer apparatus. Alternatively, the
further
pincer apparatus could be mounted with the pincers in an orthogonal position
to those
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of the first rotatable drum, so that there is no need to- rotate the smoking
articles.
Otherwise, any other folding apparatus can be used to create opposite third
and fourth
folds orthogonal to the first and second folds, -to give an envelope fold.
Figure 17 shows a.schematic side representation of a further embodiment of
apparatus for applying the foldable paper to the smoking article, and also for
folding
the overhanging foldable paper. The apparatus does not include any of the
rotating
drums described thus far. Instead, the apparatus comprises a lower horizontal
surface
140 and an upper horizontal surface 143 spaced above the lower surface 140 by
an -
amount slightly less than the width of a smoking article 54, so that a smoking
article
54 introduced into the space experiences an interference fit. The upper
surface
comprises an endless belt 143 rotating about two horizontally arranged rollers
144. A
smoking article 54 carrying a glued foldable paper 110 adhered at its leading
edge
only to the cigarette paper of the smoking article 54, is introduced into the
space
between the upper surface 142 and the lower surface 143. The foldable paper
110 may
have been prepared and applied to the smoking article 54 by any convenient
method,
including the vacuum cutting drum and associated equipment described with
respect to
Figure 2. When the smoking article 54 enters the space between the upper
surface 142
and the lower surface 140, the motion of the belt 143 forming the upper
surface 142 in
conjunction with the interference fit causes the smoking article 54 to be
rolled over the
lower surface 140. This rolling motion in turn causes the smoking article 54
to roll
over the foldable paper 110 that it is carrying, which is hence wrapped around
the
outside of the smoking article 54 and adheres to the cigarette paper because
of the glue
applied to it. In this way, the smoking article is provided with its
overhanging foldable
paper.
The lower surface 140, at a point downstream from where the smoking article
54 enters the space between the surfaces 140, 142 sufficient to allow the
foldable
paper 110 to be wrapped around the smoking article 54, is provided with a
series of
upstanding teeth 146. Each tooth 146 provides a surface that flush with the
end of the
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tobacco rod of the smoking article 54. As the smoking article 54 continues to
roll -over
the lower surface 140, the teeth 146 in turn engage a part of the overhanging
foldable
paper and push it over against the end oi the tobacco rod to create a fold, in
a similar
manner to the folding teeth described with respect to Figure 7. Each tooth
creates one
fold, to give a overlapping iris-style fold.
The teeth 146 may be omitted from the apparatus so that it just provides the
function of wrapping the glued foldable paper 110 around the smoking article
54.
Also, the lower surface 140 may be a fixed surface, or it may comprise a
rotating
endless belt 143 similar to that of the upper surface 142 that rotates at a
different speed
or direction to the upper surface belt 143 so as to provide the required
rolling of the
smoking article 54. Further, the moving upper surface may be provided by
components alternative to an endless belt rotating on rollers. Any combination
of
suitable spaced upper and lower surfaces that produce the required relative
motion to
roll the smoking article can be employed. Additionally, the rolling can be
used to carry
the smoking article past folding devices other than the teeth 146 can be used,
for
example a plough folder similar to that in Figure 6.
Further configurations of fold can be employed by adapting any of the above-
described apparatus (or using entirely different apparatus) to fold the
foldable paper
other than into an envelope fold, an iris fold or a three-way fold.
Figure 18A shows an end view of a smoking article having foldable paper that
has been closed over the tobacco by the simple technique of crushing the
foldable
paper inwards without making distinct individual folds. A suitably configured
apparatus may crush the paper such that an emb.ossed pattern or design is
applied to
the paper end.
Figure 18B shows an end view of a smoking article in which the foldable paper
has been folded using a pinch and twist fold, in this case with three folds.
The
overhanging foldable paper is pinched into a point with a plurality of folds,
three in
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this example. The folds are then twisted round to lay flat against the end
surface of the
smoking article.
Figure 18C shows an end view of a smoking article with a foldable paper that
has been folded using a two-way fold with subsequent trimming of the
overhanging
wings. Two opposite sides of the foldable paper are folded inwards, as for the
two
initial folds of an envelope fold. The two remaining parts of the paper are
then folded
outwards into the position shown by the dotted lines (instead of inwards as
for an
envelope fold), before being trimmed off. This gives a clean one-line
appearance to
the end of the smoking article.
If desired, a further processing step can be added to any technique used to
fold
over the overhanging foldable paper, including all the above techniques. It
may be
found that after folding, the foldable paper springs slightly open and away
from the
flush folded position in which the folds lie flat against the end of the
tobacco rod. This
can be addressed by pressing slightly into the folded end with a pin or rod
that has a
diameter less than that of the smoking article. The pin is moved in towards
the end of
the smoking article along t-he direction of the longitudinal axis of the
smoking article,
and by pressing inwards, the folded paper is depressed beyond the flush folded
position (since the underlying tobacco will yield slightly under the applied
pressure of
the pin) and inverted or crushed to a small amount. This inversion has been
found to
be sufficient to hold the various folds in place better than folding that is
not followed
by pressing with a pin. This is preferable to holding the folds in place with
adhesive,
since it is desirable to minimise the amount of adhesive used in a smoking
article.
Also, pressing the end of the smoking article with a pin is likely to be a
simpler
process than applying adhesive to the various folds or parts of the
overhanging paper
at the relevant times, and also does not require any on-going supply of
materials.
Any practical method and apparatus may be employed to achieve the pressing.
For example, a simple reciprocating pin mounted on a mechanism that can move
it
into the pressing position and out again could be used, with each smoking
article held
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stationary while the pirr moves. However, this will be a relatively slow step
in a
process which can otherwise be implemented with continuous motion of the
smoking
articles (such as with the apparatus-of Figure 12, for example). It-is
therefore proposed
that the pressing pin be movable along the travel path of the smoking articles
so the
pressing can be performed without halting the smoking articles.
One way of achieving this it to utilise a swash plate, which is a known
apparatus for use with rotating drums for carrying smoking articles. The swash
plate
comprises a disk in the form of a circular rim portion having a flat face, the
rim being
connected to a central hub by a plurality of springs arranged like the spokes
of a
wheel. The swash plate is rotatably mounted with its axis of rotation
coincident with
the axis of rotation of a rotating drum, and its flat face substantially
parallel with the
end face of the drum. In use, the swash plate is advanced towards the drum
while both
rotate in the same direction, and the flat face pushes against the ends of
smoking
articles carried by the drum to bring them all into alignment in the
longitudinal
direction, so that the ends are all positioned in a chosen plane. The spring-
mounting of
the rim allows any initial unevenness in the alignment of the smoking articles
to be
accommodated without any individual smoking article receiving significantly
more
pressure than the others; this reduces damage to the smoking articles.
Further, the
rotation of the swash plate in time with that of the drum avoids sideways
forces (drag)
on the smoking articles which would also cause damage.
To implement pressing into the end of folded paper with a pin according to the
present embodiment, it is proposed that a swash plate be provided with a
plurality of
pins, one pin aligned with each flute on the associated rotating drum in an
appropriate
position to press into the centre of the end of the smoking article held in
the flute. The
swash plate is moved in towards the rotating drum by a sufficient distance to
press the
pins into the folded paper by the required amount, and the rotation of the
swash plate
and its spring-mounting allow the pins to be brought to bear on the smoking
articles
without sideways drag or uneven pressure between smoking articles.
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Figure 19A shows a schematic representation of a side view of a rotating drum
with an associated pin-bearing swash plate. The drum 130 carries a plurality
of
smoking articles in the flutes- around- its circumference, and the swash plate
1-32 is
mounted to rotate about the same axis as the drum, and at the same speed. A
plurality
of pins 134, aligned with the flutes and the smoking articles 54, are arranged
on the
flat face of the swash plate 132, extending from the flat face towards the end
surface
of the drum 130. The drum 130 and the swash plate 134 rotate together, as
indicated
by the curved arrows in Figure 19A, and the swash plate 134 moves in towards
the
drum by action of a bearing 133 which moves the plate 134 towards the drum
130, as
indicated by the straight arrow. The pins 134 press into the ends of the
smoking
articles 54, and when they have protruded into the smoking articles 54 by a
sufficient
distance to invert the folded paper by the require amount to inhibit
unfolding, the
swash plate 132 is retracted away from the drum 130.
Figure 19B shows a schematic representation of an alternative apparatus for
pressing pins into the folded paper. The apparatus comprises a rotating drum
130
carrying a plurality of smoking articles 54 in flutes around its
circumference, as in
Figure 19B. In this example, however, the pins 134 extend radially outwards
from the
surface of a second rotatable drum or disc 135 which is arranged with its axis
of
rotation orthogonal to that of the rotating drum 130 carrying the smoking
articles 54.
The pins 134 lie in a plane tangential to the rotating drum 130 so that the
rotation of
the disc 135 together with the rotation of the drum 130 bring each pin 134 in
turn into
contact with the end of a smoking article 54, the spacing of the pins 134 and
the
smoking article 54 and the speed of rotation of the drum 130 and the disc 135
being
selected accordingly. The disc 54 is spaced from the drum 130 by a distance to
allow
each pin 134 to protrude slightly into the folded paper to produce the
required pressing
effect, before being withdrawn as the rotations move the pin and the smoking
article
apart. The relative rotating motion of the drum 130 and the disc 135 bring the
pins 134
to bear on the smoking articles 54 with little or no sideways drag.
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Figure 20 shows a schematic cross-sectional view through the end of a
smoking article 54 with a pin 134 on a_swash plate 132 or disc/drum 135
bearing on
the folded paper 110 that covers the end of the -tobacco in the smoking
article 54, so as
to slightly depress and invert the folded paper 110.
In the event that it is acceptable to use adhesive to secure the folds of the
folded end in place, the foldable paper can have a self-adhesive format. One
or more
areas of self-adhesive glue can be provided on the overhanging part of the
foldable
paper (preferably before it is applied to the smoking article). Depending on
the
adhesive type, the act of folding may be sufficient to cause the foldable
paper to
adhere to itself. Otherwise, an adhesive that requires the application of heat
and/or
pressure can be used. After folding, the folds can be pressed with pins using
any of the
pin arrangements described above. The pins may be heated if the adhesive is
heat-
activated, for example using electrical heating elements within the pins. If
it is not
necessary that the folds be pressed inwards by pins, the ends of the smoking
articles
may be contacted with a heated flat plate or plates (such as a heated swash
plate) to set
the adhesive.
The various folding techniques discussed above may be implemented using an
overhang of foldable paper that has a straight edge, i.e. before folding the
foldable
paper extends beyond the end of the tobacco rod by the same amount at all
points
2o around the circumference of the smoking article. In many cases, this will
give an
acceptable appearance to the finished folded end. Optionally, however, the
edge of the
foldable paper may be shaped. This can be used to reduce the amount of paper
that has
to be folded over the end of the tobacco rod, by removing paper in those areas
where
two or more layers of paper would otherwise overlap. The resulting folded end
may be
easier to light, owing to the reduced amount of paper covering the tobacco,
and may
have an improved appearance, or a particular desired appearance.
A foldable paper with a shaped edge may be more easily implemented with
techniques that apply the foldable paper to the smoking articles by wrapping
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individual pieces of foldable paper around individual smoking articles, as in
Figure 2,
for example. The process of applying the foldable paper described with respect
to
Figure 3 may also be used to provide a shaped edge, but two cutting stages
will
probably be required, one using a shaped blade to provide the shaped edge to
the
overhanging foldable paper, and one using a straight blade to provide a
straight edge
to the foldable paper at the opposite end of the tobacco rod.
Figure 21 shows some useful shapes for shaped edge foldable papers: A:
scalloped edge; B: castellated edge; C: edge with extending segment shapes,
curved to
match the curvature of the end of the smoking article. The number of scallops,
segments, etc, will depend on the number of folds to be used. Edges with other
shapes
may be also be used.
Figure 22 shows a plan view of an example of a foldable paper 110 to which
adhesive has been applied, for example by the apparatus of Figure 2. The
foldable
-paper 110 is sized to extend a short distance along the length of a tobacco
rod. Its
shorter sides are the dimension that extends along the tobacco rod and'beyond
its end
to form the overhang, and its longer sides are the dimension that encircles
the tobacco
rod. The adhesive is applied in three areas. Area A extends across the full
width of the
paper 110 in the encircling direction, and about halfway up the length of the
paper
110. This is the area that contacts the cigarette paper of the tobacco rod, so
the
foldable paper will adhere to the cigarette paper all around its
circumference, with no
adhesive from this area being on the overhanging foldable paper. Area B is a
narrow
strip of adhesive running along a length edge of the paper 110. This
corresponds to the
area of overlap when the paper 110 is wrapped around a tobacco rod, and sticks
the
overlapping edges of the paper together to form a tube extending beyond the
end of
the tobacco rod. Area C is a narrow strip of adhesive running across the width
of the
paper close to the edge that will become the far end of the overhang. This
sticks the
various folds in place as they are created by the folding devices. The
adhesive in area
C can be omitted if the folds stay sufficiently in place without it, or if
pressing in the
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folded paper, for example with a pin as in Figures 19A, 19B and -20 provides
adequate
holding. Similarly, the areas A and B may have adhesive applied in other
distributions,
such as spots or stripes rather than the continuous distribution of Figure 22.
Alternatively, the folds may be secured in place using adhesive that is
applied
during the folding process. For example, for an envelope fold such as shown in
Figure
5D, the first two folds may be made, following which adhesive is applied to
the two
opposite remaining unfolded parts of the overhanging paper before they are
folded
over. The adhesive then holds these two outside folds in place, thereby
securing the
folded end as a whole. However, for any fold arrangement, adhesive may be
applied to
any or all of the unfolded flaps or portions before they are folded over. To
achieve
this, a gluing unit may be positioned adjacent to the apparatus carrying the
smoking
articles during the folding process. For example, the gluing unit may include
one or
more glue guns operable to apply a small amount of adhesive to each flap
before
folding. Adhesive may be applied to two or more flaps or portions
simultaneously. In
the above example of the envelope fold, two glue guns may simultaneously apply
glue
to the two opposite unfolded parts. As another example, the gluing unit may
comprise
a gravure-style gummer timed to operate in synchronism with the operation of
the
folding apparatus.
Once the folded end of the smoking article has been completed (possibly
including gluing and/or pressing the folds inwards as described above), it may
be
desirable to check the quality of the folded end, so that smoking articles
with folds
which are below standard can be ejected from the production line. Quality
checking
can be achieved by including an inspection system at the end of folding
apparatus; this
may be, for example a camera-based inspection system. One or more cameras can
capture images of each folded end, and provide a signal to the apparatus to
reject the
smoking article if a defective fold is detected. Detection may be, for
example, by a
pattern recognition or image comparison technique, in which the captured
images are
compared with stored images of non-defective folded ends. If there is an
insufficient
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match between the captured and stored images, a rejection signal is generated
and sent
to the apparatus to reject the relevant smoking article. Any rejection system
can be
used, depending on the way in which the smoking articles are carried past the
inspection system. For example, if the smoking articles are carried in the
flutes of a
rotating vacuum drum, the vacuum in a flute carrying a defective smoking
article can
be switched off, thereby allowing the smoking article to drop away from the
drum.
Figure 23 shows a simplified schematic view of an inspection system, seen
from above. In this example, a rotating drum 200 carries a plurality of
smoking
articles 202 with folded ends past an inspection system 203. The inspection
system
1o 203 comprises a first camera 206 and a second camera 208 arranged next to
the drum
200, and both connected to a control unit 210. The first camera 206 is
positioned to
record an end view of the folded end of each smoking article 202, as the
smoking
articles 202 are carried past the camera 206 by the rotation of the drum 200.
The
second camera 208 is positioned to record a side view of each folded end. In
this way,
a large number of defects in the folded end can be picked up, including
defects in the
attachment of the overhanging paper to the smoking article. However, an
inspection
system may include just one camera, arranged to capture an end view or a side
view,
or a view intermediate between the side and the end.
The images from the first camera 206 and the second camera 208 are sent to
the control unit 210 for processing, such as by comparison with stored images
of non-
defective folded ends. In the event that the processing detects a defect, the
control unit
210 generates a reject signal, which is sent by a control line 212 to a
controller 204 of
the rotating drum 200 to cause operation of a rejection mechanism that rejects
the
defective smoking article. The images should be captured in a timed manner
with
regard to the rotation of the drum, so that the rejection mechanism operates
on the
correct smoking article.
Any of the techniques described herein for providing a smoking article with an
overhanging foldable paper may be combined with any of the techniques
described
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herein for folding the overhanging foldable paper. Moreover, any of the
described
techniques may be combined with techniques similar to those described to
achieve the
descri'bed end result of a smoking article having an overhanging foldable
paperthat is
folded over to cover the tobacco. Further, techniques similar to those
described may be
used to achieve the described end result. In addition, the techniques
described herein
for folding the overhanging foldable paper may alternatively be used to fold
overhanging paper that is not a separately applied foldable paper such as that
described herein, but is instead an extending portion of the cigarette paper
that wraps
the tobacco of the tobacco rod.
When considering the various embodiments of apparatus described herein,
components for adhering the foldable paper to the smoking articles may be
thought of
as a first sub-apparatus, components for folding the overhanging foldable
paper may
be thought of as a second sub-apparatus, components for pressing pins into the
folded
paper to enhance the folding effect may be thought of as a third sub-
apparatus, and
any further components employed to attach filter units to any smoking articles
that are
only partially complete when the foldable paper is adhered may be thought of
as a
fourth sub-apparatus. To increase the speed of production, the number of first
and/or
second sub-apparatuses in the apparatus as a whole may be increased. For
example,
two folding apparatuses or two apparatuses for adhering the foldable paper may
be
arranged in parallel to supply twice the quantity of smoking articles to the
downstream
parts of the apparatus.
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REFERENCES
1. US 1,164,118
2. US 501,498
3. US. 903,101
4. US 3,208,458
5. GB 278,534
