WO2013045915A1

WO2013045915A1 - Smoking articles

Info

Publication number: WO2013045915A1
Application number: PCT/GB2012/052377
Authority: WO
Inventors: Karl Kaljura
Original assignee: British American Tobacco (Investments) Limited
Priority date: 2011-09-29
Filing date: 2012-09-26
Publication date: 2013-04-04
Also published as: GB201116866D0

Abstract

A smoking article (1) comprising a first ventilation area (32) movable relative to a second ventilation area (30) along a path to control a lev¬ el of ventilation by an overlap between the first and second ventilation areas. The first ventilation area (32) and/or second ventilation area (30) is configured such that the overlap has an increasing rate of change with respect to a position along the path of the first ventilation area (32) relative to a second ventilation area (30).

Description

Smoking Articles

Description

The present disclosure relates to smoking articles, filter assemblies for smoking articles, and components for smoking articles.

EP 0,228,211 describes a filter device for a smoking rod, in which a plurality of apertures are formed on a wrapper. The wrapper is rotatable such that the apertures are rotatable into and out of alignment with an air permeable part of the filter, formed by a notch. The ventilating apertures extend uniformly in a circumferential row. The present disclosure improves on the state of the art, as set forth herein.

The present invention provides, in a first aspect, a smoking article comprising: a first ventilation area movable relative to a second ventilation area along a path to control a level of ventilation by an overlap between the first and second ventilation areas, wherein the first ventilation area and/ or second ventilation area is configured such that the overlap has an increasing rate of change with respect to a position along the path. The present invention provides, in a second aspect, a filter assembly for a smoking article comprising: a first part comprising a first ventilation area movable relative to a second part comprising a second ventilation area along a path to control a level of ventilation by an overlap between the first and second ventilation areas, the first part and/ or second part comprising at least one filter section, and wherein the first ventilation area and/ or second ventilation area is configured such that the overlap has an increasing rate of change with respect to a position along the path of the first ventilation area relative to a second ventilation area.

The present invention provides, in a third aspect, a component for a smoking article comprising: a first part comprising a first ventilation area configured to be movable relative to a second part comprising a second ventilation area along a path to control a level of ventilation by an overlap between the first and second ventilation areas, wherein the first ventilation area is configured such that the overlap has an increasing rate of change with respect to a position along the path of the first ventilation area relative to a second ventilation area.

Various embodiments of the present invention(s) will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which: Figure 1 is a graph illustrating the relationship between ventilation level and angle of rotation for a related art smoking article;

Figure 2 is a perspective view of an exemplary smoking article in a partially formed state according to some embodiments;

Figure 3 is a perspective view of part of an exemplary smoking article according to some embodiments;

Figure 4a is a schematic view of a first exemplary embodiment of ventilation apertures according to the present invention;

Figure 4b is a schematic view of a second exemplary embodiment of ventilation apertures according to the present invention;

Figure 5 is a schematic view of a third exemplary embodiment of ventilation apertures according to the present invention; and

Figure 6 is a graph illustrating the relationship between ventilation level and angle of rotation for an exemplary smoking article according to some embodiments of the present invention.

Figure 1 shows an analysis of a ventilation level 100 of a smoking article determined in the development of the present invention. The smoking article has a row of uniform ventilation apertures, which may be selectively aligned with a larger ventilation aperture by rotation. An uncovered ventilation aperture allows ventilation air into the smoking article. The graph illustrates that at zero degrees of rotation, zero ventilation apertures are uncovered. The number of ventilation apertures uncovered, proportional to the area of ventilation apertures uncovered, is proportional to the angle of rotation. The ventilation level 100 is seen to increase as a part is rotated, and the number of ventilation apertures aligned with the ventilation window increases. However, the relationship between the rotation of a part of the smoking article and level of ventilation is not proportional. In particular, it has been determined that the relationship between ventilating area and level of ventilation is not proportional. When relatively few ventilation apertures are uncovered, uncovering a further ventilation aperture has a relatively large effect on the ventilation level. When relatively many ventilation apertures are already uncovered, uncovering a further ventilation aperture has a relatively small effect on the ventilation level. The angle of rotation required to increase the ventilation level by a particular amount varies over the range of rotation.

The ventilating area is defined herein as the area of overlap between the ventilation areas of components that are relatively displaceable, which allows ventilating air to pass into the smoking article, and in particular, into the filter.

The level of ventilation may be based on the amount of ventilating air which is permitted to enter the smoking article, and in particular the filter, during use. The ventilating air may be considered as the air entering the filter through controllable ventilation areas only, or alternatively, may be considered as the air entering through the controllable ventilation areas and a base level of ventilation, for example, from any fixed ventilation areas and/ or through an exterior covering of the filter (i.e. paper wrapping having a permeability). The level of ventilation is generally expressed as a percentage, based on the ventilating air entering the filter as a proportion of the total air drawn from the filter.

The level of ventilation shown in figure 1 is based on the air entering the filter through controllable ventilation areas only, as a proportion of the total air drawn from the filter. The x-axis scale of angle of rotation may be replaced by a linear measure of the number of equally sized ventilation apertures which are uncovered, which is proportional to the angle of rotation.

Figures 2 and 3 show an example of a smoking article according to an embodiment of the present invention. The smoking article may be an article such as a cigarette, cigar or cigarillo, whether based on tobacco, tobacco derivatives, expanded tobacco, reconstituted tobacco or tobacco substitutes and also heat-not-burn products (i.e. products in which flavour is generated from a smoking material by the application of heat without causing combustion of the material). For convenience, these will be referred to as "smoking articles" in this specification.

Figure 2 shows a smoking article 1 in a partially formed state. The smoking article 1 comprises a first part having a source of smokable material 11 , which is preferably tobacco. The source of smokable material 11 is in the form of a tobacco rod. The smoking article 1 further comprises a filter assembly 10 attached to the source of smokable material 11. The smoking article comprises a movable part, movable to select a ventilation level. In this example, the movement is a rotation. In some embodiments, the smoking article may optionally comprise a limiting mechanism, configured to limit movement to a pre-determined range.

The filter assembly 10 may comprise a first filter section 12 and a second filter section 14. The first filter section 12 may be attached to the source of smokable material to form a single unit. The tobacco rod and first filter section 12 may be connected with a covering layer to affix the first filter section 12 to the tobacco rod, for example formed of tipping paper. The tobacco rod and first filter section may be referred to as a first part of the smoking article, or as a tobacco unit. The elongate tobacco rod and first filter section define a longitudinal axis of the smoking article.

A second part of the smoking article comprises the second filter section 14. The second filter section 14 is co-axial with the first filter section 12, and is located rearwardly of the first filter section 12. The second part of the smoking article further comprises a sleeve 13 in the form of a cylindrical tube extending around the circumference of the tobacco rod 11 and/ or first filter section 12. The material of the sleeve 13 is substantially impermeable to air, and may be formed as a cylinder of paper. The tobacco rod and first filter section are dimensioned to rotate as a unit around a longitudinal axis within the sleeve 13. The second filter section 14 is at a mouthpiece end of the sleeve 13, adjacent to the first filter section 12. The second filter section 14 is securely attached and fixed within the sleeve. The first and/ or second filter sections are preferably made of a conventional filtration material, e.g. cellulose acetate tow. The filtration material may be wrapped in a sheet material, preferably paper, e.g. plugwrap. Exemplary embodiments of smoking articles are provided with a ventilation system configured to allow adjustment of a ventilation of the smoking article. The ventilation system comprises one or more ventilation areas, comprising and/ or defining ventilation apertures or air permeable material, in one or each of the first part and second part. For example, when ventilation areas in the sleeve and layers of sheet material around the first and/ or second filter sections are aligned or overlap, air can flow into the body of the first and/ or second filter section. The ventilation is selected by selecting a position of the second part relative to the first part. The position may be measured in degrees of rotation. The range of rotation may be limited to a predetermined range between a minimum and maximum ventilation, for example, 120 degrees.

The tobacco unit 11 ,12 may comprise one or more first ventilation areas 32. In some aspects, the first ventilation area 32 is in the form of a plurality of discrete ventilation areas in a circumferentially extending area. The first ventilation area is elongate, in this example, in a circumferential direction. The first ventilation area may extend circumferentially over only a part of the circumference. The first ventilation areas may extend along or from a single longitudinal position. The first ventilation aperture 32 allows ingress of air into the tobacco unit, for example, into the first filter section 12. The first ventilation area 32 may be one or more apertures or air permeable areas allowing air into the filtration material of the first filter section 12, through the layers of generally impermeable sheet material surrounding the filtration material.

The sleeve 13 may be provided with one or more second ventilation areas 30. The sleeve 13 may comprise a single second ventilation aperture 30 extending

circumferentially over only a part of the circumference. The second ventilation aperture 30 may be located at a single longitudinal position. For example, the second ventilation aperture 30 may be in the form of a narrow circumferential slit. The second ventilation area is elongate, in this illustrative example, in a

circumferential direction.

Ventilation through the first and second ventilation areas 30, 32 is dependent on alignment of the defined apertures which cooperate to form an overlapping opening area, which is determined by the rotational position of the first part of the smoking article relative to the second part of the smoking article. The second ventilation area 30 may be movable relative to the first ventilation area 32 along a path, to control a ventilation level by an overlap between the first and second ventilation areas. In this example, the path is a circumferential path, along which the second ventilation area is moved by rotation of the second part. The variation in ventilation is controlled by the degree of overlap between the first and second ventilation areas 30,32. In particular, between the minimum and maximum ventilation, a part only of the first ventilation area is aligned with a part only of the second ventilation area. The ventilation level is determined by the smaller of the first or second ventilation areas in the overlapping region.

In particular illustrative embodiments of the present invention(s), the first ventilation area 32 is not uniform along its length. The first ventilation area 32 can be varied in area along a path over which the second ventilation area moves. In this example, the ventilating area of the first ventilation area 32 varies along a

circumferential path. The overlap area of the first and second ventilation areas has an increasing rate of change with respect to a position of the first ventilation area 32 relative to a second ventilation area 30. The overlap area providing ventilation increases on relative movement in a first direction between the first and second ventilation areas towards a higher ventilation of the smoking article, and in addition, the rate of change of the overlap area increases with position in the first direction. The first direction corresponds with a direction in which the ventilation of the smoking article 1 increases, i.e. the overlap with the second ventilation area increases.

In particular, the ventilation area of the first ventilation area 32 per unit length along the path increases in a first direction. The first ventilation area 32 is configured such that an increasing ventilating area per unit length of the second ventilation area moves into overlap with the second ventilation area. Thus, the ventilating area provided by an overlap between the first and second ventilation areas increases in the first direction. Thus, the increase in ventilating area is not linear (or proportional) to the respective displacement of the first and second parts. Instead, the overlap or ventilating area can vary or increase in a non-linear manner. In particular, the effective ventilating area increases as a function which increases more quickly with position than a function which is linear (proportional) (i.e. a fixed relationship or first order relationship) to the position of the first and second parts. In other words, the overlap or ventilating area is higher than a linear relationship with relative displacement of the first part and second part. In some embodiments, the function of the ventilation area with position results in a level of ventilation of the filter, or smoking article, which is substantially linear (proportional) relative to the position of the first part relative to the second part. In some embodiments, the increase in ventilation area can be substantially linear with respect to the relative displacement of the first and second parts. The position of the first part relative to the second part is along the path of movement, in the first direction.

Figure 3 shows an enlarged view of the exemplary smoking article 1. In this example, the second ventilation area 30 is a single aperture extending

circumferentially. The second ventilation aperture 30 has a longitudinal extent which is larger than the longitudinal extent of the first ventilation area 32. The ventilating area may be determined solely or in part by the degree of overlap between the extent of the first and second ventilation areas 30, 32 along the path of movement. The first ventilation area 32 comprises a plurality of discrete ventilation areas, termed ventilation elements 34. Each ventilation element 34 may be a discrete aperture. The configuration of the ventilation elements 34 provides for the level of ventilation described above. The ventilation elements 34 may have a pattern, sizing and/or spacing which varies such that a ventilating area per unit length increases in the first direction. The ventilating area of the first ventilation area is determined by the sum of the ventilation elements per unit length or overlapping the second ventilation area. Figure 4 a shows a first exemplary embodiment of first ventilation area 132, which may be used with any embodiment described. The first ventilation area 132 comprises a plurality of discrete first ventilation elements 134 configured to provide ventilation. The first ventilation elements 134 sequentially increase in area in the first direction. The first direction is shown as left to right, with a second ventilation area (not shown) to the left of the ventilation elements 134. The first direction may correspond with a circumferential direction in order of increasing ventilation when the first part is rotatable relative to the second part, as in the example above. For example, the initial first ventilation element 134 to be aligned with the second ventilation aperture is at one end, which is the smallest ventilation element 134a. The first ventilation elements 134 are aligned in a row. The next first ventilation element 134 in the row is the next to be engaged. In some examples, each first ventilation element 134 is larger than the preceding one in the first direction. The last first ventilation element 134 to overlap with the second ventilation area is at the opposite end to the initial first ventilation element 134a, namely the largest first ventilation element 134b.

The first ventilation area 132 comprises a plurality of first ventilation elements, such as openings or areas that are perforated, 134 which consecutively increase in size in the first direction. The first ventilation elements 134 may have a circular outline, as in the example shown. Alternatively, the first ventilation elements 134 may have any shape, for example, square, triangular, elliptical or rectangular. One or more dimensions of each first ventilation element 134 may consecutively increase. For example, a dimension parallel to the path of movement may increase and/ or a dimension perpendicular to the path of the movement may increase. For the circular first ventilation elements 134 shown, the diameter increases, i.e. a dimension parallel to the path of movement increases and a dimension perpendicular to the path of the movement increases. The shapes of the first ventilation elements 134 do not need to have axes parallel or perpendicular to the path of the movement. The ventilating area of each first ventilation elements 134 determines the level of ventilation.

The spacing of the first ventilation elements 134 may be substantially uniform. For example, the centre of the first ventilation elements 134 may be substantially constant, although as the dimensions of the first ventilation elements 134 increase, the extent of impermeable material between the first ventilation elements 134 may decrease or stay constant. Alternatively, the spacing between centres of the first ventilation elements may increase or decrease. The extent of impermeable material between the first ventilation elements 134 may stay constant, decrease or increase, in any combination.

Figure 4b shows a second embodiment of first ventilation area 232, which may be used with any embodiment described. The first ventilation area 232 comprises a plurality of discrete first ventilation elements 234 configured to provide ventilation. The first ventilation elements 234 sequentially increase in area in the first direction. The first direction is shown as left to right, as in the example above. The initial first ventilation element 234 to be aligned with the second ventilation aperture may be at one end, which is the smallest ventilation element 234a. The first ventilation elements 234 may be aligned in a row. The next first ventilation element 234 in the row is the next to be engaged. In some examples, each first ventilation element 234 is larger than the preceding one in the first direction. The last first ventilation element 234 to overlap with the second ventilation area is at the opposite end to the initial first ventilation element 234a, namely the largest first ventilation element 234b.

As illustrated, the first ventilation area 232 comprises a plurality of first ventilation elements 234 which consecutively increase in size in the first direction. The first ventilation elements 234 may have a substantially rectangular outline, as in the example shown. Along the path of movement, a dimension parallel to the path of movement may increase and a dimension perpendicular to the path of the movement is constant. The spacing between the first ventilation elements, i.e.

extent of impermeable material between the first ventilation elements 234, may be substantially constant.

In Figures 4a and 4b, the second ventilation area overlaps with an increasing area of the first ventilation area, as the first ventilation area is moved relative to the second ventilation area. For example, the second ventilation area may overlap from zero area of the first ventilation area to a maximum area determined by the area of the first and/ or second ventilation area. When the first and second ventilation areas are partially overlapping, an impermeable area aligned with the path of movement prevents ventilation through a non-aligned region. The first and second ventilation area may have substantially the same extent, such that the maximum ventilation is when the first and second ventilation areas are fully aligned. The increase in level of ventilation along the path of movement is derived from both the conventional increasing overlap between the areas over which first and second ventilation areas extend, and the variation in first ventilation area dimensions, spacing or

configuration, as described above according to the present invention(s).

Figure 5 shows a third embodiment of first ventilation area 332, which may be used with any embodiment described. The first ventilation area 332 comprises a plurality of discrete first ventilation elements 334 configured to provide ventilation. The first ventilation area 332 has a configuration which substantially provides an increase in ventilating area over a path of movement of a second ventilation area 130 in the first direction. The first direction is shown as left to right, as in the example above.

The first ventilation area increases in ventilating area by varying the number of first ventilation elements 334 in a direction perpendicular to the path of movement. For example, the first ventilation elements 334 may be arranged in an array or other pattern. The number of rows in the array varies along the path of movement. The number of rows may vary from one to the number of rows which fit within the second ventilation area 130. The rows may extend beyond the second ventilation area 130 in a direction perpendicular to the path of movement, but such rows may not contribute to ventilation.

The first ventilation elements 334 may be configured to each have substantially the same area. The spacing of each first ventilation element 334 also may be

substantially constant. The change in ventilation area may be provided in some embodiments only by the extent that the first ventilation area is perpendicular to the path of relative movement. Alternatively, the first ventilation elements 334 may each have an area and/ or spacing which varies. The variation in spacing may allow the first ventilation area to comprise an increasing number of first ventilation elements in the first direction per unit length. In some implementations, the spacing of the first ventilation elements may decrease in the first direction. The second ventilation area 130 may be movable relative to the first ventilation area 332 from left to right, as shown. The second ventilation area 130 may be in a first position 130a with respect to the first ventilation area 332, corresponding to a relatively low ventilation. The second ventilation area 130 is accordingly aligned with a plurality of first ventilation elements 334 having a relatively low area. The first ventilation elements 334 overlapping with the second ventilation area 130 in the first position 130a may be arranged in a single row.

In a second illustrative position 130b, the second ventilation area 130 is aligned with a greater area of first ventilation area, by virtue of alignment with a greater number of rows of first ventilation elements 334.

In a third illustrative position 130c, the second ventilation area 130 is aligned with a still greater area of first ventilation area, by virtue of alignment with a still greater number of rows of first ventilation elements 334. The smoking article has a maximum ventilation when the second ventilation area 130 is in the third position 130c.

As illustrated in Figure 5, the whole of the second ventilation area may be aligned with a portion of the first ventilation area (ventilating and non-ventilating) from positions 130a to 130c, which is different to the examples of Figures 4a and 4b. In Figure 5, the increase in rate of change of the ventilating area from positions 130a to 130c is derived from the increase in proportion of ventilating area (compared to a non-ventilating area) of the first ventilation area, which is present within an area corresponding to the second ventilation area. For example, the ventilation can be considered as determined by the ventilating area of the first part within a constant area (which is the whole of the first ventilation area). This contrasts with the embodiments above, in which the ventilation can be considered as determined by the ventilating area of the first part within a variable area, determined by the variable overlap between the overlapping areas of the first and second ventilation areas. In accordance with some embodiments of the present invention, the first ventilation area may define a ventilating area per unit length which increases with relative displacement of the ventilation areas. The increase in the effective ventilation area is thus not linear (i.e. not constant) with respect to the relative displacement, but is non-linear, and thus has an increasing rate of change (increase) with respect to relative displacement, such as the angle of rotation.

Figure 6 shows an illustrative example of an expected ventilation level 400 of a smoking article according to some embodiments of the present invention, which is varied by rotation. The graph illustrates that at zero degrees of rotation, zero controllable ventilation apertures are uncovered. As the angle of rotation increases, the number of ventilation apertures uncovered increases, and the area of uncovered ventilation apertures increases. This relationship between angle of rotation and number or uncovered area of ventilation apertures is not linear, as described above. The filter is configured such that the ventilation level 400 increases substantially linearly, and in particular proportionally, to the angle of rotation of the first part relative to the second part. The angle of rotation required to increase the ventilation level through the controllable ventilation areas by a particular amount is

substantially constant over the range of rotation. That is to say, the relationship is linear or substantially linear. Thus, discrete relative movements of the first part with respect to the second results in the same change in level of ventilation for each movement, independently of the actual level of ventilation, i.e. whether the level of ventilation is relatively low or high. This contrasts with the art shown in Figure 1, where a particular movement at a high ventilation would be expected to have a relatively small effect on the level of ventilation.

The level of ventilation shown in figure 6 is based on the air entering the filter through controllable ventilation areas only, as a proportion of the total air drawn from the filter. The effect of ventilating air entering through fixed size ventilation areas and/ or through permeable wrapping of the filter, which may provide a base level of ventilation, is not illustrated. Including the base level of ventilation would provide a relationship having a non-zero, base, level of ventilation at zero angle of rotation. The level of ventilation, including the base ventilation air, may have a substantially linear relationship with the angle of rotation between the first and second parts. A linear equation may be written in which the level of ventilation is substantially equal to a product of a first constant (or slope) and angle of rotation, plus the base level of ventilation (second constant).

Alternatively, the level of ventilation may be linear when including the ventilating air entering through the controllable (variable) ventilation areas only. Including the base ventilation air in the level of ventilation results in a non-linear relationship between the level of ventilation and the angle of rotation. The level of ventilation is still closer to a linear relationship with the displacement between the first and second parts than is conventionally known.

In figure 6, the x-axis scale of angle of rotation may be replaced by the number of equally sized ventilation apertures, or the ventilation area which is uncovered. These quantities would not be uniformly spaced along the x-axis, but each unit would be increasingly closely spaced in order to correspond with a linearly rising level of ventilation. The definition of a zero degree of rotation providing zero uncovered ventilation areas is arbitrary. The smoking article or filter may be defined such that at zero degrees of rotation, a pre-defined ventilation area is uncovered. This does not affect the linear relationship between the angle of rotation and the level of ventilation. The present examples provide for a ventilating area which substantially increases per unit length along the path of relative movement. The increase is not required to be a continuous increase, in which any movement results in an increase of ventilating area per unit length. For example, the spacing of discrete first ventilation elements with air impermeable areas means that movement to additionally align an impermeable area with the second ventilation area will not result in an increase in ventilation. Alternatively, the increase in size of the first ventilation elements does not need to be in consecutive first ventilation elements. For example, two or more first ventilation elements may have the same dimensions, with further first ventilation elements having the different dimensions. Thus, the increase of ventilating area per unit length can be a general trend, for example, over substantially the whole range of movement of the first part. In some examples, the disclosed embodiments may include one or more regions within the range of movement in which the ventilating area does not increase per unit length, and still provides an increase of ventilating area per unit length over substantially the whole range of movement.

The ventilating area through which air can flow into the smoking article through the first and second ventilation areas has been described in some embodiments, for example, as being nonlinear, such that there exists an increasing rate of change with respect to a position of the first ventilation area relative to a second ventilation area. Thus, the overlap area is greater than a proportional increase (i.e. fixed ratio, or constant slope term) in overlap area with respect to position along the path, and the amount of the increase in area will be larger towards higher ventilations. This relationship between ventilating area and position may apply to the whole range of relative movement between the first and second ventilation areas, a substantial part of the range of relative movement, or only a part of the range of relative movement. In mathematical terms, a derivative of the ventilating area with respect to position along the path of movement is a function of the position along the path of movement and/or, a second derivative of the ventilating area with respect to position along the path of movement is non-zero, and in particular, is a positive amount.

In some aspects, the sleeve 13 comprises one or more further ventilation areas 35. The further ventilation area(s) 35 may provide ventilation which is independent of the rotational position of the position of the first and second parts of the smoking article. The further ventilation area(s) 35 may provide a base level, or minimum, ventilation to the smoking article. The further ventilation area(s) 35 may allow air through the sleeve, and into the second filter section 14. The second filter section 14 comprises filtration material surrounded by a porous paper wrap (e.g. plugwrap), which allows the ventilating air into the filtration material of the second filter section 14. The further ventilation area 35 may comprise a plurality of apertures extending circumferentially in a line. In some implementations, the sleeve 13 comprises a separation line 36, which extends substantially circumferentially. The sleeve may be configured to easily break along the separation line 36 into a forward part and a rearward part. The rearward part is affixed to the second filter section 14. The forward part is affixed to the first filter section 12, for example, by adhesive. Optionally, the forward part of the sleeve 13 may connect the tobacco rod 11 and first filter section 12. The separation line 36 may be defined by a plurality of perforations through the sheet material (e.g. paper) of the sleeve 13. In use, the forward and rearward parts of the sleeve may be initially connected. The smoking article may have a defined initial ventilation, set by the further ventilation area 35, and a pre-determined initial alignment of the first and second ventilation areas 30, 32. In some embodiments, the sleeve is not readily rotatable (or slidable) relative to the tobacco unit. In some implementations, application of a rotational force to the rearward part of the sleeve 13, relative to the tobacco unit, breaks the sleeve 13 along the separation line 36. The sleeve 13 is then rotatable to vary the ventilation by alignment of the first and second ventilation areas.

The ventilation areas in the sleeve and/ or tobacco unit may be formed as apertures by a laser. For example, the laser may simultaneously generate aligned ventilation apertures in the sleeve and tobacco unit. Alternatively, the ventilation apertures may be formed as a slit by a mechanical cutting tool. Alternatively, the ventilation apertures may be formed as a cut-out area. Alternatively, the ventilation areas may be formed by an air permeable material, which is either manufactured as a permeable material or made permeable by the addition of apertures or by

processing.

The smoking article may optionally comprise a limiting mechanism configured to limit rotation between the first and second parts. The limiting mechanism may be configured to limit rotation to a pre-determined range. In some aspects, the pre- determined range of rotation may be through an angle of from 90 to 180 degrees, and may be, for example, 120 degrees. The limiting mechanism may limit rotation between a position in which the first and second ventilation areas have no overlap, and a further position in which the first and second ventilation areas are in full overlap.

The position of the second part relative to the first part may be controlled by an indexing mechanism such as a ratchet, pawl and detent mechanism or indexer, configured to provide indexed rotation between a plurality of discrete positions. The control mechanism may optionally provide an audible sound indicating movement to or from the selected position. The indexing mechanism may comprise a first indexing section (or surface) 18 on the tobacco unit, for example, on the first filter section 12. The first indexing section can be engaged with a second indexing section (or surface) 19 on the sleeve 13. The indexing mechanism may provide a number of indexed positions, in some implementations at least three, preferably at least five or seven, within a limited range of rotation, e.g. 90 or 120 degrees.

In an exemplary indexing mechanism, the first indexing section 18 has a plurality of depressions which are engageable by a protruding feature on the second indexing section. The depressions preferably form a corrugated exterior surface, comprising a plurality of elongate grooves, separated by ridges, which extend substantially longitudinally.

The second indexing section 19 may comprise one or more protrusions which are engageable with the first indexing section 18. The protrusion(s) may comprise one or more pawls, formed by one or more layers of sheet material which are folded to extend radially inwardly from the sleeve 13. The term "pawl" is intended to mean any type of protrusion which can engage with an indexing section to allow indexed movement in two directions. The pawl may be formed on a substrate 20, which may be a sheet material, for example, paper. The substrate may be affixed to an interior surface of the sleeve 13. The substrate may be folded to define the pawl as an upstanding ridge of sheet material, forming an edged peak. The pawl may have a substantially triangular cross-section. The indexing mechanism may be separate and distinct from the limiting mechanism configured to limit the range of rotation between the first and second parts.

The smoking article may be configured to restrain the sleeve 13 from moving longitudinally over the tobacco unit. For example, the grooves, and optionally ridges, of the first indexing section 18 may have a radius which is less than forwardly and rearwardly adjacent parts of the first part. The second indexing section 19 is configured to engage with the forwardly and rearwardly adjacent parts, such that the second indexing section is retained longitudinally within the first indexing section. The first indexing section may have a longitudinal extent which is substantially the same as the second indexing section to prevent relative longitudinal movement between the first and second parts.

The first and/ or second filter section may comprise an adsorbent additive. In some examples, the adsorbent additive may be carbon, for example, charcoal and in particular, activated carbon. Alternatively, the adsorbent additive may be a resin. In some aspects, the adsorbent additive may be distributed within the filtration material of the first filter section 12. The adsorbent additive may be substantially uniformly distributed in the filtration material. The adsorbent additive may be granules of carbon.

The first ventilation elements of any embodiment may be in a single row, or may be in more than one row, or an irregular number of rows that may or may not be aligned with the path through which the first and second ventilation apertures align. The first ventilation elements may be in arranged in a straight line or regular array. Alternatively, the first ventilation elements may be in arranged in any arrangement which allows overlapping with the second ventilation area according to some embodiments. For example, the row of first ventilation elements may not be straight or aligned with the path of movement, and/ or the array may be irregular.

Alternatively, the first ventilation area of any embodiment may vary by having an increasing number of ventilation elements perpendicularly to the path of movement.

The second ventilation area has been described as rotatable relative to a first ventilation area to control a ventilation level. Alternatively, the second ventilation area may be slidable longitudinally relative to a first ventilation area to control a ventilation level. The relative longitudinal movement of the first and second parts is parallel to the longitudinal axis of the smoking article. Rotational and longitudinal movement can similarly be combined to provide helical relative movement between the first and second parts. Any of the embodiments described may be equally applicable to a longitudinal movement and position. In particular, the path of movement is longitudinal, with the first direction in a forward or rearward direction to increase the level of ventilation. The position may be measured as a linear length along the path of movement. The longitudinal movement of the two parts may be a telescopic movement with the sleeve of the second part slidable around an exterior of the first part. The extendable smoking article may comprise a limiter or other limiting means to limit extension and/ or an indexing means to provide indexed positions.

The first ventilation area has been described as located on an inner, first part of the smoking article, and the second ventilation area as located on an outer, second part of the smoking article, which surrounds a part of the first part. Alternatively, the described configuration of the first ventilation area may be used for the second ventilation area on the second part, and/ or, the described configuration of the second ventilation area may be used for the first ventilation area on the first part. The first or second ventilation areas may be used as the inner or outer ventilation area, since the ventilating area is determined by the overlap between the first and second ventilation areas.

The first ventilation area has been described as having a ventilating area which increases per unit length, and the second ventilation area has been described as having a constant area per unit length. Alternatively, both the first ventilation area and second ventilation area may have a ventilating area which increases per unit length. The ventilating area increases per unit length in a first direction towards an increasing ventilation, for example, as the overall overlap increases of the regions around the first and second ventilation areas. The first direction for the first ventilation area is therefore in an opposite direction to the second ventilation area, e.g. opposite rotational sense, or opposite longitudinal direction.

The second ventilation area has been described as a single area or aperture.

Alternatively, the second ventilation area may comprise a plurality of discrete ventilation areas, termed ventilation elements. Each ventilation element may be a discrete aperture. The configuration of the ventilation element provides for the ventilation level described above. The ventilation elements may have a pattern, sizing and/ or spacing which varies such that a ventilating area per unit length increases in the first direction. Alternatively, the ventilation elements may define a ventilating area which is substantially constant in the first direction. The ventilating area of the second ventilation area is determined by the sum of the ventilation elements per unit length or overlapping the first ventilation area.

Some disclosed embodiments have been described as features of a smoking article. Alternatively, the features described may be provided on a filter assembly or a component of a smoking article.

The smoking article has been described as having components formed from layers of sheet material, e.g. paper, defining the ventilation areas. Alternatively, different materials may be used. For example, one or more components allowing movement between the first and second part may be made of a plastics material. Such component(s) may also define the ventilation area(s), for example, as apertures.

The disclosure has been described as applied to a smoking article. Any of the features may also be applicable to a filter for a smoking article, a filter assembly for a smoking article or a component of a smoking article. In particular, the ventilation is provided into the filter, and so the filter and associated assembly providing the first and second parts may form the basis of the invention. Any of the features may also apply to a method of manufacturing a filter or a smoking article.

Any of the features of any embodiment may be combined with any of the features of any other embodiment. Embodiments of the invention(s) are configured to comply with applicable laws and/ or regulations, such as, by way of non-limiting example, regulations relating to yields, constituents, testing, and/ or the like. For example, the invention may be configured such that a smoking article implementing the invention is compliant with applicable regulations before and after adjustment by a user. Such implementations may be configured to be compliant with applicable regulations in all user-selectable positions. In some embodiments, the configuration is such that a smoking article implementing the invention meets or exceeds required regulatory test(s) in all user- selectable positions, such as, by way of non-limiting example, the testing

threshold(s)/ceiling(s) for cigarette yields and/or smoke constituents.

Many other modifications and variations will be evident to those skilled in the art, that fall within the scope of the following claims.

Claims

1. A smoking article comprising:

a first ventilation area movable relative to a second ventilation area along a path to control a level of ventilation by an overlap between the first and second ventilation areas,

wherein the first ventilation area and/ or second ventilation area is

configured such that the overlap has an increasing rate of change with respect to a position along the path.

2. The smoking article as claimed in claim 1 wherein the first ventilation area and/ or second ventilation area has a ventilating area which increases per unit length along the path in a first direction corresponding to an increasing level of ventilation.

3. The smoking article as claimed in claim 1 or 2 wherein the first ventilation area and/ or second ventilation area is configured such that the level of ventilation of the smoking article is substantially proportional to a position along the path of the second ventilation area relative to the first ventilation area.

4. The smoking article as claimed in any one of the preceding claims wherein the first ventilation area comprises a plurality of discrete first ventilation elements configured to provide ventilation, wherein consecutive first ventilation elements increase in area along the path.

5. The smoking article as claimed in claim 4 wherein the consecutive first ventilation elements each increase in a dimension parallel to the path and/ or perpendicular to the path.

6. The smoking article as claimed in claim 4 or 5 wherein a spacing of the first ventilation elements ventilation areas is uniform.

7. The smoking article as claimed in claim 4, 5 or 6 wherein the first ventilation area comprises an increasing number of first ventilation elements per unit length.

8. The smoking article as claimed in claim 7 wherein the spacing of the first ventilation elements decreases in the first direction.

9. The smoking article as claimed in claim 7 or 8 wherein the number of first ventilation elements arranged perpendicularly to the first direction per unit length increases along the path.

10. The smoking article as claimed in claim 9 wherein the first ventilation elements are arranged in an array comprising rows substantially aligned with the path, wherein a number of the rows per unit length increases in a first direction corresponding to an increasing level of ventilation.

11. The smoking article as claimed in any one of the preceding claims wherein the first and/ or second ventilation area comprises one or more apertures, and optionally, a second ventilation element is an aperture.

12. The smoking article as claimed in any one of the preceding claims wherein the first ventilation area is rotatable relative to the second ventilation area to control the level of ventilation.

13. The smoking article as claimed in any one of claims 1 to 12 wherein the first ventilation area is slidable longitudinally relative to a second ventilation area to control a level of ventilation.

14. The smoking article as claimed in any one of the preceding claims wherein the smoking article comprises:

a first part comprising the first ventilation area, and

a second part comprising the second ventilation area,

wherein one of the first or second parts comprises a sleeve movable around the other of the first or second parts.

15. The smoking article as claimed in any one of the preceding claims wherein the smoking article comprises a limiting mechanism configured to limit movement between the first and second parts to a pre-determined range, and

optionally, the first and second ventilation areas are configured such that a ventilation level of the smoking article is substantially proportional to a position of the first and second parts in the pre-determined range.

16. The smoking article as claimed in any one of the preceding claims wherein an area of overlap providing the effective ventilation area varies non-linearly with respect to the relative position along the path.

17. A filter assembly for a smoking article comprising:

a first part comprising a first ventilation area movable relative to a second part comprising a second ventilation area along a path to control a level of ventilation by an overlap between the first and second ventilation areas,

the first part and/ or second part comprising at least one filter section, and wherein the first ventilation area and/ or second ventilation area is configured such that the overlap has an increasing rate of change with respect to a position along the path of the first ventilation area relative to a second ventilation area.

18. A component for a smoking article comprising:

a first part comprising a first ventilation area configured to be movable relative to a second part comprising a second ventilation area along a path to control a level of ventilation by an overlap between the first and second ventilation areas,

wherein the first ventilation area is configured such that the overlap has an increasing rate of change with respect to a position along the path of the first ventilation area relative to a second ventilation area.

19. A smoking article comprising:

a first ventilation area movable relative to a second ventilation area along a path, wherein the first and second ventilation areas cooperate to form an effective ventilation area of the smoking article that is defined by the overlap in the first and second ventilation areas, the effective ventilation area being configured to control the amount of air that can be drawn through a portion of the smoking article,

wherein the effective ventilation area increases in an amount that is not linear with respect to the relative displacement between the first ventilation area and second ventilation area.

20. The smoking article of claim 19 wherein the area of the first ventilation area and/ or second ventilation area increases per unit length along the path in a first direction corresponding to an increasing level of ventilation.

21. The smoking article of claim 19 or 20 wherein the smoking article includes a limiter adapted and configured to limit movement between the first and second parts to a pre-determined range.

22. A component for a smoking article comprising:

a first part including a first ventilation area configured to be movable relative to a second part including a second ventilation area along a path to control a level of ventilation by an overlapping area defined by the overlap of the first and second ventilation areas,

wherein the first ventilation area is configured such that the area of the overlapping area increases in a manner that is not linear with respect to the relative displacement of the first and second ventilation areas.

23. A filter assembly for a smoking article comprising:

a first part comprising a first ventilation area movable relative to a second part comprising a second ventilation area along a path to control a level of ventilation by way of an effective ventilation area defined by the overlap of the first and second ventilation areas,

at least one of the first part and second part including at least one filter section, wherein the magnitude of the effective ventilation area increases in a manner that is not linear with respect to the relative displacement of the first part and second part.

24. A method of manufacturing a smoking article comprising:

forming a first part having a first ventilation area;

forming a second part having a second ventilation area;

attaching the first and second parts, such that the first and second parts are movable along a path to control a level of ventilation by an overlap between the first and second ventilation areas,

wherein the first ventilation area and/ or second ventilation area are formed such that the overlap has an increasing rate of change with respect to a position along the path.