Field of Invention The present invention relates to aerosol generating articles, and more specifically extendable filters for aerosol generating articles.

Background Aerosol generating articles such as traditional cigarettes include a tobacco rod which is lit at one end, whilst being held, and drawn on via inhalation, at an opposite end. During smoking, smoke from the lit end can flow along an external length of the cigarette as side stream smoke, and interact with fingers of a person holding the cigarette. This smoke can leave the fingers discoloured and smelling of smoke.

It is therefore an aim of the present invention to reduce finger contamination by side stream smoke. Summary of Invention

The foregoing aim of the invention, as well as other aspects, is addressed by the claims. In an aspect of the disclosure, there is provided an extendable filter for an aerosol generating article comprising an aerosol generating device, the filter comprising a filter plug having a first end portion configured for attachment to an aerosol delivery end of the aerosol generating device, a second end portion, opposite the first end portion, and a core portion therebetween, wherein the filter plug is shaped such that the second end portion has a diameter that is greater than diameter of the core portion, and a sleeve that surrounds the filter plug and is capable of axial movement relative to the filter plug whereby to extend the length of the filter, wherein a portion of the sleeve is configured to interfere with the second end portion of the filter plug during axial movement of the sleeve along the core portion so as to limit a distance the sleeve can be moved and thereby prevent axial separation of the sleeve from the filter plug.

In this way, the filter can be extended to increase the distance between the lit end of an aerosol generating article and the hand of a consumer holding the aerosol generating article. This reduces the effects of side stream smoke contaminating the hands of the consumer. Moreover, because the filter is extendable, the aerosol generating article can be packaged in a compacted (i.e. non-extended) arrangement therefore requiring no increase in the size of the packaging.

Preferably, the second end portion is configured as an abutment integral with the filter plug and arranged to interfere with the interfering portion of the sleeve. In this way, the sleeve is prevented from separating from the filter plug when the sleeve moves in a direction away from the first end portion of the filter plug.

Preferably, the filter plug is formed from a single piece of material comprising the first end portion, the second end portion and the core portion. In this way, the manufacturing of the filter is simplified as multiple parts do not need to be combined to form the filter plug.

Preferably, the diameter of the second end portion is equal to a diameter of the first end portion. In this way, the first end portion of the filter plug inhibits the sleeve from sliding over it. Consequently, the sleeve is inhibited from sliding over an aerosol generating device attached to the filter.

Alternatively, the diameter of the core portion is equal to a diameter of the first end portion. In this way manufacture is simplified as only one change is diameter is required.

Preferably, an internal diameter of said interfering portion of the sleeve is less than an internal diameter of a remaining portion of the sleeve. In this way, the part of the sleeve with reduced diameter can abut the second end portion of the filter plug whilst allowing the remaining portion of the sleeve to pass over the second end portion of the filter plug. Preferably, said interfering portion of the sleeve is provided at an end of the sleeve distal to the second end portion of the filter plug. In this way, the sleeve can provide a maximal extension to the length of the filter plug when moving from a compacted arrangement, in which the sleeve overlays the filter plug, to an extended arrangement in which the sleeve extends from the filter plug.

Preferably, said interfering portion is formed by part of the sleeve being folded back on itself, inwardly, to form a return edge. In this way, the interfering portion can be manufactured in a simple and low cost manner with no further components required.

Preferably, the core portion of the filter plug has a constant diameter. In this way, the sleeve can smoothly slide along the core portion of the filter plug.

Preferably, the second end portion of the filter plug is formed as a flange. In this way, the portion of the sleeve is configured to interfere with the second end portion of the filter plug does so by abutting the outward extension created by the flange.

Preferably, the second end portion of the filter plug has an external diameter substantially equal to the external diameter of said aerosol generating device to which the filter plug is arranged to be attached, and wherein the first end portion is arranged to be fitted to the aerosol delivery end of the aerosol generating device, for example by a connecting wrap. In this way the filter plug is securely attachable to an aerosol generating device.

Preferably, the sleeve comprises a rigid material, preferably any of a cellulosic material, a natural or synthetic polymer material or a combination thereof.

Preferably, axial movement of the sleeve relative to the filter plug exposes part of the core portion along its length.

Preferably, the core portion of the filter has a length configured to allow the filter to be extended by approximately 15 mm. In this way the length of the filter is increased enough to substantially decrease the amount of side stream smoke contaminating the fingers of a consumer holding an aerosol generating article including the filter. According to another aspect of the disclosure there is provided an aerosol generating article comprising an aerosol generating device and an extendable filter according to any preceding claim attached at the aerosol delivery end thereof. In this way, the filter can be extended to increase the distance between the lit end of the aerosol generating article and the hand of a consumer holding the aerosol generating article. This reduces the effects of side stream smoke contaminating the hands of the consumer. Moreover, because the filter is extendable, the aerosol generating article can be packaged in a compacted (i.e. non-extended) arrangement therefore requiring no increase in the size of the packaging.

Preferably, the aerosol generating device comprises a charge of an aerosol generating material, preferably in a fluid, a pulverulent, a solid form or a combination thereof.

Preferably, the aerosol generating material comprises tobacco.

It will be understood that the present invention is described herein purely by way of example, and modifications of detail can be made within the scope of the invention.

Brief Description of the Drawings

Embodiments of the invention are now described, by way of example, with reference to the drawings, in which:

Figure 1 shows a smoking article in the form of a standard cigarette;

Figures 2A and 2B show cross-sectional views of a smoking article with an extendable filter, the extendable filter in compacted and extended arrangements respectively;

Figures 3A and 3B show perspective views of the smoking article with an extendable filter, the extendable filter in compacted and extended arrangements respectively; and Figure 4 shows an enhanced cross-sectional view of a filter portion of the smoking article with an extendable filter.

Detailed Description

Figure 1 illustrates a smoking article 100. The smoking article 100 has a smoking portion 103 joined to a filter portion 105. The smoking portion 103 comprises an aerosol generating material 107, in particular a tobacco based aerosol generating material comprising any of natural or reconstituted tobacco leaves, sheets, fibres, crumbs or shreds, arranged in a rod-type shape, and wrapped in wrapping paper 109 along the elongate edge.

The filter portion 105 comprises a filter plug 1 13 that provides filtration of particles in an aerosol generated when the aerosol generating material 107 is heated to a determined temperature of about 200°C to 400°C, preferably about 250°C to 350°C in the case of a typical heat-not-burn smoking article, respectively combusted in a standard cigarette case. Typically a filter plug 1 13 is wrapped by an inner plug wrap paper.

When constructing the smoking article 100, an end of the filter portion 105 and an end of the smoking portion 103 are brought into contact with one another; tipping paper 1 11 is wrapped around substantially the entire filter portion 105 and a section of the smoking portion 103 so as to connect the filter portion 105 to the smoking portion 103.

In this example, the smoking article 100 is a standard cigarette 100. As such, the smoking portion 103 may be provided by a tobacco rod 103. In typical use, a consumer of the cigarette 100 lights a distal end 103a of the smoking portion 103 and draws (i.e. inhales or sucks) on the distal end 105a of the filter portion 105, while holding the filter portion 105, to inhale the generated smoke. In between draws, smoke exiting the distal end 103a of the tobacco portion 103 of the cigarette 100 has a tendency to travel along the external length of the cigarette 100 as side stream smoke toward the fingers of the consumer holding the cigarette 100; this smoke can interact with the fingers of the consumer holding the cigarette 100 resulting in a smoke smell and discolouration of the fingers.

Figures 2A, 2B, 3A, 3B and 4 show schematic views of a smoking article 200, in this case a cigarette 200, in an embodiment of the invention. The reference to a “smoking article” shall in the context of the present invention and description not be construed as limited to cigarettes or other kinds of tobacco products requiring burning of tobacco material to generate an aerosol inhaled by a user. The terms smoking article shall to the contrary apply and be construed to also encompass any kind of aerosol generating devices making use of tobacco containing substrates, be it plain tobacco leaves, tobacco cut-filler, reconstituted tobacco or tobacco extracts in all forms, for generating an inhalable aerosol through any kind of heating technique. It may in particular encompass any heat-not-burn tobacco containing consumable device used in connection with a filter for consumption by users.

The cigarette 200 has an extendable filter according to the invention. Figures 2A and 3A show the cigarette 200 with the filter portion 205 in a compacted arrangement; Figure 2B and 3B show the cigarette with the filter portion 205 in an extended arrangement.

The cigarette 200 has a tobacco portion or tobacco rod 203 similar to that described with reference to the standard cigarette 100 of Figure 1. The tobacco rod 203 comprises tobacco fibres 207 arranged in a rod-like shape and wrapped in a wrapping paper 209.

The cigarette 200, has a filter portion 205 connected to the tobacco rod 203. The filter portion 205 has a filter plug 213 that is cylindrical in shape, having a first end portion 215 arranged for connection to a distal end of the tobacco rod 203 for aerosol (such as tobacco smoke) delivery, and a second end portion 217 opposite the first end portion 215. A core portion 219 is arranged between, and separating, the first end portion 215 and the second end portion 217. The end portions have a greater diameter than the core portion 219 between the two end portions. That is, the filter plug 213 has a cross-section with an“I” shape. The first end portion 215 and the second end portion 217 can have the same diameter. The core portion 219 has a constant diameter; that is, the core portion 219 has a consistent diameter along its length. The first end portion 215 and the second end portion 217 can also have a constant diameter.

In an alternative arrangement (not shown), the first end portion 215 may have a different diameter to the second end portion 217, and the core portion 219 may have a smaller diameter than the second end portion 217 and the first end portion 215.

In another alternative arrangement (not shown), the first end point may have the same diameter as the core portion 219, but said diameter may be smaller than the diameter of the second end portion 217.

The filter plug 213, including the core portion 219, first end portion 215 and second end portion 217 are formed from a single piece of material, such that the core portion 219, first end portion 215 and second end portion 217 are integral to the filter plug 213. In a preferred example, the filter plug 213 is made from cellulose acetate. Other filter plug materials can include cotton and paper based materials. In some examples, the filter plug 213 material is surrounded by a filter wrap, for example made from a paper-based material; the filter wrap material can be cellulose based, with various porosity levels as required for adjusting ventilation and tar/nicotine levels.

A sleeve 221 surrounds the filter plug 213. The sleeve 221 is arranged to overlay the core portion 219 and second end portion 217 of the filter plug 213 in the compacted arrangement, and to slide axially along the core portion 219 away from the tobacco rod 203 when moving the extendable filter from the compacted arrangement to the extended arrangement. The sleeve 221 can be made of a rigid paper, or any other suitable cellulosic material, natural or synthetic polymer material or a combination thereof. The sleeve 221 may be wrapped by tipping paper; in this case the material of the sleeve may be thicker than the tipping paper. Alternatively, the sleeve 221 may itself be made from tipping paper. The sleeve 221 has two portions, a first portion at an end of the sleeve 221 arranged to be relatively toward the tobacco rod 203 when compared to a second portion comprising the remaining portion 225 of the sleeve 221.

The first portion of the sleeve 221 is inwardly folded, forming a return edge. The sleeve 221 , with the end folded in, is dimensioned to be approximately equal in length to the combined length of the second end portion 217 and the core portion 219 of the filter plug 213. The inner diameter of the inwardly folded portion 223, or first portion, of the sleeve 221 is less than the inner diameter of the remaining portion 225, or second portion, of the sleeve 221. The inner diameter of the inwardly folded portion 223 of the sleeve 221 is approximately equal to, or greater than, the outer diameter of the core portion 219 of the filter plug 213, but less than the outer diameter of the second end portion 217 of the filter plug 213. The inner diameter of the remaining portion 225 of the sleeve 221 is equal to or greater than the diameter of the second end portion 217 of the filter plug 213.

Thus, when the sleeve 221 slides away from the tobacco rod 203, the remaining portion 225 of the sleeve 221 passes over the second end portion 217 of the filter plug 213 until the inwardly folded portion 223 of the sleeve 221 abuts the second end portion 217 of the filter plug 213, as depicted in Figure 2B. This abutment between the inwardly folded portion 223 of the sleeve 221 and the second end portion 217 of the filter plug 213 interferes with the movement of the sleeve 221 and limits the distance the sleeve 221 can be moved so as to prevent the sleeve 221 from sliding off, i.e. separating from, the filter plug 213. An enhanced view 400 of this interaction is shown in Figure 4. That is, the interaction between the inwardly folded portion 223 of the sleeve 221 and the second end portion 217 of the filter plug 213 forms a hard stop for the movement of the sleeve 221 away from the tobacco rod 203. When the sleeve 221 reaches this abutment, the extendable filter is arranged in the extended arrangement.

In other words, the second end portion 217 is integral with the filter plug 213, and arranged as a flange extending radially outward from the filter plug 213 against which the inwardly folded portion or end 223 of the sleeve 221 abuts when sliding away from the first end of the filter plug 213.

From the extended arrangement, the sleeve 221 can slide axially along the core portion 219 toward the tobacco rod 203 when moving the extendable filter from the extended arrangement to the compacted arrangement.

In embodiments in which the first end portion 215 also has a diameter greater than the core portion 219 and the internal diameter of the inwardly folded portion 223, the axial movement of the sleeve 221 over the tobacco rod 203e is inhibited by the inwardly folded portion 223 of the sleeve 221 abutting the first end portion 215 of the filter plug 213. That is, in such embodiments, the first end portion 215 is integral with the filter plug 213, and arranged as a flange extending radially outward from the filter plug 213 against which the inwardly folded end 223 of the sleeve 221 abuts when sliding away from the second end of the filter plug 213. This inhibits the sleeve 221 from sliding off the first end of the filter plug 213 or over a tobacco rod 203 attached to the first end of the filter plug 213.

The reduced diameter of the core portion 219 of the filter plug 213, compared to the first end portion 215 allows for the sleeve 221 to be substantially flush to the tobacco rod 203, in terms of outer diameter, when in the compacted arrangement such that the entire cigarette has a substantially constant outer diameter in the compacted arrangement.

In an example, the sleeve 221 can slide through a displacement 229 of about 15 cm along the core portion 219 between the compacted arrangement and the extended arrangement. In alternative examples, other suitable displacements that are greater or smaller can be used as appropriate.

In the compacted arrangement, the end of the sleeve 221 opposite the inwardly folded end 223 is aligned with the second end portion 217 of the filter plug 213 and the sleeve 221 surrounds the core portion 219 and the second end portion 217 of the filter plug 213. In the extended arrangement the sleeve 221 surrounds the second end portion 217 but not the entire core portion 219, only the region covered by the inwardly folded portion 223 of the sleeve 221. That is, the axial movement of the sleeve 221 toward and away from the first end portion 215 of the filter plug 213 covers and exposes part of the core portion 219 along its length.

The second end portion 217 of the filter plug 213 has an external diameter substantially equal to the external diameter of the tobacco rod 203 to which the filter plug 213 is arranged to be attached. The first end portion 215 is arranged to be fitted to the aerosol delivery end of the tobacco rod 203, i.e. an end of the tobacco rod 203 opposite to the end that is lit during smoking. The extendable filter may be attachable to a tobacco rod 203 by way of a connecting wrap 227, for example a connecting paper wrap 227, which overlaps both the first end portion 215 of the filter plug 213, and the aerosol delivery end of the tobacco rod 203. For example, the connecting wrap 227 may overlay a portion (or the entirety) of the first end portion 215 of the filter plug 213 and also overlay a portion of the wrapping paper 209 surrounding the tobacco fibres 207 at the aerosol delivery end of the tobacco rod 203, thereby connecting the extendable filter to the tobacco rod 203.

In use, a consumer of a cigarette, in which the extendable filter is attached to a tobacco rod 203, pulls the sleeve 221 so as to move it from the compacted position to the extended position. The inwardly folded portion 223 of the sleeve 221 abuts the second end portion 217 of the filter plug 213 which provides a stop and indicates to the consumer that the filter is fully extended (as well as preventing the sleeve 221 being separated from the filter).

The consumer can then light the distal end 203a of the tobacco rod 203, i.e. the end of the tobacco rod 203 away from the end connected to the first end portion 215 of the filter plug 213. The consumer can draw on the end 205a of the sleeve 221 opposite the inwardly folded end 223, i.e. the opposite distal end of the cigarette to the lit end, and aerosol generated by the burning tobacco passes through the filter plug 213, where it is filtered, through the and sleeve 221 which acts as a tube connecting the filter plug to the mouth of the consumer where the aerosol is inhaled.

Advantageously, the extension to the filter portion 205, provided by the sleeve 221 being in the extended arrangement, increases the distance between the hand of the consumer and the lit end of the cigarette when compared to a standard cigarette. This increased distance reduces the amount of side stream smoke reaching the hand of the consumer and leaving the fingers discoloured and smelling of smoke.

It will be understood to the skilled person that features from the various examples described herein can be readily substituted with one another, where appropriate.