Technical field of the invention

The present invention relates to aerosol-generating devices.

Background of the invention

Aerosol-generating devices are nowadays increasingly used as a substitution for regular cigarettes. A particular type of aerosol-generating devices is heat-not-burn devices (HnB), which heat an aerosol-generating substrate rather than bum or combust it to generate an aerosol inhalable by a user.

A heat-not-burn aerosol-generating device typically comprises a heating cavity adapted to receive at least part of a consumable aerosolgenerating article inserted therein, and a heating system for heating the article contained in said cavity.

The aerosol-generating article contains a tobacco substrate comprising an aerosol-forming substance (such as glycerine and/or propylene glycol) which vaporises during heating and creates a vapour that extracts nicotine and flavour components from the tobacco substrate. The aerosol-forming substance is heated to between 200 and 400°C, which is below the normal burning temperatures of a conventional cigarette.

Volatile compounds and aerosol released upon heating of the tobacco substrate become deposited on internal surfaces of the aerosol-generating device. Also, pieces or particles of the aerosol-generating articles themselves, such as pieces or particles from their wrapper or of the substrate, may come off when the article is manipulated or in use.

External materials - such as dust - may further penetrate inside the heating cavity between uses.

All such residues are particularly deposited on the lateral surfaces of the heating cavity. They may be further accumulated and/or partially removed by the friction of inserted aerosol-generating articles. Such residues hinder optimal use of the aerosol-generating device. When accumulated on the walls of the heating cavity, they can diminish or block the required air flow of the device. The residues may also affect the optimal flavour sensation of the aerosol. Indeed, the contamination pieces or particles may impart an unpleasant or bitter flavour to a user. Also, the heater may be damaged depending on how and where the residues are deposited.

Nowadays, users generally clean their devices themselves, using dedicated cleaning tools such as brushes. Apart from the unpleasant experience it may represent and the heavy burden it puts on the user, this manual cleaning may also be prejudicial for both sustainability of the device and user’s experience. The heater may be damaged by either too much or too few cleaning operations. Also, insufficient cleaning may lead to degradation of the user’s sensations during vaping and unpleasant smell.

There is thus a need to improve management of residues inside aerosol-generating devices, to improve the user’s experience while vaping and to more globally enhance sustainability of the device.

Summary of the invention

This is achieved with an aerosol-generating device, comprising

- a heating cavity extending in a longitudinal direction along a longitudinal axis and delimited by a lateral wall in a lateral direction orthogonal to said longitudinal direction, the heating cavity being provided with an opening at one upper end and being adapted to receive at least part of an aerosol-generating article inserted through said opening, and

- a heating system for heating an aerosol-generating article received in said heating cavity, the aerosol-generating device being characterized in that it further comprises an integrated cleaning tool configured to be longitudinally moved within the heating cavity upon actuation of an actuator and comprising at least one cleaning member configured to flexibly rub the lateral wall of the heating cavity when moving along said heating cavity. According to the invention, the aerosol-generating device is provided with a cleaning system including a dedicated cleaning tool and an actuator actuating the cleaning tool when a cleaning session is triggered.

The cleaning tool may for example be operated automatically by a controlling unit integrated in the device, said controlling unit being configured to control one or several parameters, such as for example a time period and/or a number of vaping sessions since the last cleaning session and/or a temperature of the heating system and/or a charging state of the battery and/or a resistance or impedance at the lateral wall of the cavity, and being configured to trigger the actuator based on said parameter(s).

In addition or as an alternative, the cleaning tool may be operated based on actuation of a user’s command, such as an actuation button on the device.

In particular, the actuator may be actuated depending on actual cleaning needs, in particular depending on one or several parameters representative of a level of contamination of the heating cavity, typically measured by at least one sensor.

According to the invention, the cleaning tool comprises at least one cleaning member at its periphery, with said cleaning member being deformed against the lateral wall of the heating cavity to rub or brush said lateral wall.

At least one lateral dimension of the cleaning tool (in a non-mounted state) may for example be greater than the lateral dimensions of the cavity.

When the cleaning tool is moved in the longitudinal direction, the cleaning member(s), elastically biased against the lateral wall, take off residues deposited on said lateral wall. Once removed from the wall, residues may be easily evacuated for example by a simple turnaround of the device.

Automated cleaning provided by such cleaning tool improves the user’s experience as it removes the burden of manual cleaning. It also ensures consistency in the cleaning operation: The heating cavity is constantly kept in good condition, improving the user’s sensation while vaping, as well as sustainability of the device. In the following, a lateral direction is a direction orthogonal to the longitudinal axis of the heating cavity and intersecting said axis. In the absence of indication to the contrary, a transversal plane is a plane orthogonal to the longitudinal direction.

The cleaning tool may have various shapes and arrangements which will be described in more detail hereafter.

The cleaning tool may comprise one single cleaning member or a plurality of cleaning members.

According to an embodiment, the length of each cleaning member, measured in a lateral direction, may be comprised between 0.1 and 1 mm.

A thickness of each cleaning member, measured in the longitudinal direction, may preferably be comprised between 0.01 and 0.5mm, still more preferably between 0.05 and 0.2 mm.

The cleaning tool may be moved along the cavity with only one degree of freedom (translation in the longitudinal direction, without rotation) or it may be moved with two degrees of freedom (i.e. simultaneously translated in the longitudinal direction and rotated around the longitudinal axis of the cavity).

An arrangement of the cleaning member(s) may be chosen notably depending on the thickness of each cleaning member, on the presence or absence of a rotating movement of the tool, on the translation and/or rotation speed of the tool, with an aim to brush a maximum area of the lateral wall of the cavity at least once during one longitudinal movement of the tool.

Advantageously, the location of the cleaning member(s) may also be adapted to the shape of the heating cavity and/or to the position of particular elements of the device, depending on their need for cleaning or on the contrary on their fragility (some components are easily breakable and a direct contact between these components and the cleaning tool should be avoided).

Advantageously, the integrated cleaning tool may comprise a plurality of cleaning members deformable independently from each other. Each cleaning member being flexible, it may conform to the inner shape of the heating cavity, which may or may not be circular. Providing several cleaning members which are deformable independently from each other and may each flex accurately depending on the parts of the heating cavity against which it is rubbing, allows better conforming to the shape of the cavity and hence efficient cleaning.

Cleaning members are provided at the periphery of the cleaning tool, to flexibly rub the lateral wall of the heating cavity when moving along said heating cavity.

For example, the integrated cleaning tool may comprise a plurality of spaced apart cleaning members.

Cleaning members may be distributed on the entire or on part of the tool periphery, preferably in a regular arrangement, in particular in one single cleaning layer.

According to an embodiment each cleaning member may have an elongated shape in a lateral direction (hereafter referred to as the main direction/axis of said particular cleaning member).

A section of a cleaning member, orthogonally to its main axis, may be circular, rectangular, or of any other shape.

According to an embodiment, a maximum dimension of each cleaning member measured in a plane orthogonal to its main axis may be comprised between 0.01 and 0.5 mm, preferably between 0.05 and 0.2 mm.

According to an embodiment, each cleaning member may be inscribed in an angular sector of less than 1 °, even less than 0.5°, around the longitudinal axis.

The multiple cleaning members may be spaced widely apart. According to an example, only four elongated cleaning members may be arranged in cross-shape around the tool periphery, with two adjacent cleaning members forming a 90° angle. According to another preferable embodiment, the cleaning tool may comprise a plurality of juxtaposed cleaning members forming a cleaning comb. Each cleaning member then forms a tooth of the comb, with the multiple cleaning members tightly arranged next to each other.

Such cleaning comb may extend all along a periphery of the tool (i.e. at 360° around the longitudinal axis). Or it may extend only on a part or angular portion at said periphery.

According to another embodiment, at least one cleaning member may be a flexible spatula, with a flat and wide blade-shape.

Such flexible spatula may extend continuously all along a periphery of the tool (i.e. at 360° around the longitudinal axis). Or it may extend only on a part or angular portion at said periphery.

The or each cleaning member may be made of plastic such as silicone or polyetheretherketone (PEEK), or of metal, such as stainless steel, or of any other adapted material.

The or each cleaning member may also be coated, either partially (in particular at its tip end) or entirely, to enhance the rubbing action. The coating may for example include polytetrafluoroethylene (PTFE), silicon, or any other adapted material. Such coating may be applied for example by dipping, or by dipping and centrifugation, or by any other coating techniques.

According to an embodiment, and in order to facilitate the release of debris that have been brushed by the cleaning member(s), the cleaning tool may comprise, at its periphery and in particular seen in transversal projection, at least one cleaning zone including at least one cleaning member and at least one free zone, with the or each free zone extending on an angular sector of at least 35° around the longitudinal axis, preferably of at least 70° around said longitudinal axis.

More particularly, the cleaning tool may comprise, at its periphery, an alternance of such cleaning zones and free zones. In the present application, a cleaning zone should be understood as formed by one cleaning member or by a plurality of tightly juxtaposed cleaning members. In particular:

A cleaning zone may be formed of one single cleaning member, typically extending continuously on an angular section of at least 35°, preferably at least 70°, around the longitudinal axis.

As an alternative, a cleaning zone may comprise a cleaning comb formed of a plurality of juxtaposed cleaning members extending laterally.

A cleaning member or a plurality of cleaning members may be defined in one plane, typically a transversal plane or a plane inclined with respect to a transversal plane, forming a so-called cleaning layer.

According to a particular embodiment, the cleaning tool may comprise several cleaning layers superimposed in the longitudinal direction, each layer including typically one or several cleaning members and/or zones.

According to an embodiment, the cleaning tool may comprise at least one air channel arranged on both a lateral side and an upper side thereof.

The air channel is configured to allow a passage of air from a lateral side of the cleaning tool towards an upper side thereof. Hence the cleaning tool allows the air to flow towards the tip of the tobacco stick, which is necessary for vaping efficiency.

The cleaning tool typically comprises a central tool body and each cleaning member is formed at the periphery of said tool body.

According to an embodiment, each cleaning member may be integrally formed with said body.

According to another embodiment, the cleaning tool may comprise a body and the at least one cleaning member may be detachably fixed to said body. The cleaning member(s) may so easily be replaced, if needed, for example due to use. In particular, the cleaning tool may comprise securing means for securing the cleaning member(s) to the tool body.

According to a particular embodiment, the body may comprise an upper body part and a lower body part, acting as clamping jaws. The cleaning tool may further be provided with fixing means for fixing the upper and lower body parts to each other, typically threaded fixing means.

According to an embodiment, each cleaning member may form a portion of an independent cleaning module, independently detachable from the tool body.

As an advantageous alternative, to facilitate both assembly and disassembly of several cleaning members from the tool body, the cleaning tool may comprise at least one single-piece cleaning module including several - preferably all - cleaning members and detachably fixed to the tool body.

In particular, several cleaning members forming one cleaning zone may be joined together, typically at a central base, to form one cleaning module.

Still further, cleaning members of one cleaning zone may be joined to the members of other cleaning zones to form one cleaning module.

In the comb-like configuration mentioned above, a cleaning module may be formed by etching a sheet of metal, e.g., stainless steel or titanium to form cleaning members at the periphery thereof.

According to an alternative embodiment, a cleaning module may be formed of a folded wire, with pleats of the wire forming cleaning members.

According to an embodiment, the cleaning tool may be provided with a collecting cup located under the cleaning zone(s), to collect debris brushed by the cleaning member(s) as the tool is moved in the cavity. The cleaning members and the collecting cup may be integrally formed (molded or injected) or may be fastenable and removable from each other and/or from the tool body, for example by press fit/screw/magnet engagement. The heating cavity extends in the longitudinal direction, along a longitudinal axis, and is delimited, in the lateral direction orthogonal to said axis, by a lateral wall. The cavity has generally a tubular shape. It is fixed with respect to an outer body of the device.

More generally, the device comprises an outer body in which the heating cavity, the heating system and an electrical power source are received, and the heating cavity, the heating system and the electrical power source are all fixed with respect to each other and with respect to said outer body.

The heating cavity is provided with an insertion opening at its insertion end. This opening shall allow introduction of the aerosol-generating article inside the cavity.

In the present disclosure, and in the absence of specific statement to the contrary, the terms top, bottom, upper, lower, are considered with respect to the longitudinal axis of the heating cavity, top and upper portions being oriented towards the insertion end of said cavity, and bottom and lower portions being oriented towards the opposite end thereof.

According to an embodiment, the cleaning tool may be configured to be stored in a retracted position at a bottom end of the heating cavity when the actuator is at rest. In its retracted position, the cleaning tool then forms a bottom portion of the heating cavity, thus allowing the aerosol-generating article to take the required position inside said cavity for normal vaping use.

The heating system may include a heater surrounding the heating cavity and configured to heat said heating cavity.

Such heater may typically include a heater body in the form of a longitudinal metal sleeve, and a heating element, such as a thick or thin film heater comprising a layer of electrically insulating material and a layer of electrically conductive material outside or within the heater body.

The heater body may also be made of ceramic.

As an alternative, the heating system may comprise an induction coil, typically surrounding the heating cavity, configured to heat by induction a ferromagnetic material forming part or the entirety of the heating cavity or contained in the aerosol-generating article.

According to an embodiment, the heater body may have a cup shape. That is, the heater body may have a lateral tubular wall and a bottom wall.

According to an embodiment, the heater body may be solidary with a holder, typically made of high-temperature resistant plastic, configured to hold said heater body at its lower end. The holder may have a base orthogonal to the longitudinal direction of the heating cavity and holding means such as longitudinal tongues upwardly protruding from the base, configured to hold the heater body, for example by clamping.

In particular, the holding means may be configured to hold the heater body at a distance from the base.

According to an embodiment, the actuator configured to actuate the longitudinal movement of the cleaning tool inside the heating cavity is a mechanical linear actuator also known as a lead-screw actuator of the screw-nut type, comprising a screw or shaft extending in the longitudinal direction and a nut threadedly engaging said screw.

The actuator may further comprise a motor for driving the screw.

The rotary motor may have a direct or indirect drive, and, in the case of an indirect drive, have its axis either aligned with or offset with respect to the screw axis.

According to an advantageous embodiment, the actuator may comprise a reduction gearing between the motor and the screw. Such reduction gearing may transfer the rotational movement of the motor axis to the screw while decreasing speed and increasing the torque delivered to the screw. The reduction gearing may for example comprise a first cogwheel solidary with the motor axis and a second cogwheel solidary with or engaging with the screw.

According to an embodiment, the nut is fixed in the longitudinal direction of the heating cavity, the screw is translatable in the longitudinal direction upon rotation of the nut, and the cleaning tool is solidary with the screw. In such type of actuator also known as a non-captive linear actuator, the cleaning tool rotates together with the screw while moving along the heating cavity. To allow the movement, the cleaning tool has typically a circular section to conform to a circular cross-section of the heating cavity.

In an embodiment including a reduction gearing as described hereabove, a cogwheel of said reduction gearing may be provided with a threaded hole for engaging with the screw and may so form the nut.

According to another embodiment, the tool body may be supported in a free rotatable manner at the end of the screw, for example by at least one ball bearing. According to one example, the hub of the ball bearing may be formed by a supporting element solidary with the top end of the screw and the shaft of the ball bearing may be solidary with the tool body, or vice versa.

According to still another embodiment, the screw is fixed in the longitudinal direction of the heating cavity, the nut is translatable in said longitudinal direction upon rotation of the screw, and the nut is formed by or solidary with the cleaning tool. This embodiment has the advantage of not cluttering up the space located under the heating cavity.

For cavities having non-circular sections, the cleaning tool may be fixed with one degree of freedom to move longitudinally without rotating.

In an embodiment including a reduction gearing as described hereabove, a cogwheel of the reduction gearing may be fixedly attached to the screw.

According to an embodiment, the screw may be laterally offset with respect to a center axis of the heating cavity.

In an embodiment where the heater body is a cup, the screw may go through an opening formed in the bottom wall of the heater body.

The edges of the bottom wall around the screw opening may then advantageously be turned upwardly to prevent dirt from falling into the device. An additional seal, for example a silicone seal, may further be placed around said opening to prevent the dirt from falling out. According to an embodiment, the device may comprise a controlling unit for controlling one or several parameters, notably one or several parameters representative of a level of contamination of the heating cavity, and actuate the actuator based on said parameter(s).

In particular, the device may comprise at least one sensor configured to measure at least one parameter representative of a level of contamination of the heating cavity and send a corresponding signal to the controlling unit.

The invention further concerns a cleaning method of an aerosolgenerating device as defined hereabove, comprising actuating the actuator to achieve longitudinal movement of the cleaning tool inside the heating cavity.

According to an embodiment, the cleaning method further comprises measuring at least one parameter representative of a level of contamination of the heating cavity in a closed loop and actuating the actuator based on said parameter.

Any sensor configured to assess a dirt level in the cavity may be implemented in the method. The measured parameter may be either directly related to the contamination level, or it may allow predicting said contamination level.

In particular, the at least one parameter may be a resistance or impedance at the lateral wall typically formed by the heater body and/or a time period since the last cleaning session and/or a number of vaping sessions since the last cleaning session and/or a temperature of the heating system and/or a charging state of the battery.

According to an advantageous embodiment, the measuring step may include measuring an electrical resistance or impedance.

According to an embodiment, the cleaning step may include moving the cleaning tool several times back and forth along the cavity at different speeds and/or with different temperatures in the heating cavity.

It is to be understood that the different embodiments mentioned hereabove can be realized singly or in any technically compatible combinations. In particular, the aforementioned technical features and those to be explained in the following can be used not only in the combinations indicated, but also in other combinations or alone, without departing from the scope of the present invention.

Brief description of the drawings

Figure 1A is a schematical sectional view of an aerosol-generating device according to an embodiment of the present invention; with the cleaning tool in its retracted position where it forms the bottom of the heating cavity;

Figure 1 B is a sectional view of the aerosol-generating device of figure 1A, with the cleaning tool in its most deployed position;

Figure 2 is a view of detail II of figure 1 B;

Figure 3 is a partial perspective view of the actuator of figures 1A, 1 B and 2.

Figure 4 illustrates a one-axis actuator, having its motor aligned with the screw;

Figure 5 illustrates a cleaning tool having a two-parts tool body and detachable cleaning members;

Figure 6 is a perspective view of the upper body part of the cleaning tool of figure 5;

Figure 7 is a perspective view of a cleaning tool comprising a cleaning comb formed of juxtaposed cleaning members;

Figure 8 is a partial perspective view of a cleaning tool having coated cleaning members;

Figure 9 is a perspective view of a cleaning tool including a cleaning module formed of a folded wire;

Figure 10 is a perspective view of a cleaning tool comprising a spatulashaped cleaning member; Figure 11 is a perspective view of a cleaning tool having alternated cleaning zones and free zones along its perimeter;

Figure 12 is a sectional view of a cleaning tool having two superimposed cleaning layers;

Figure 13 is a sectional view of a cleaning tool comprising a collecting cup for collecting debris brushed by the cleaning members;

Figure 14 is a sectional view of a cleaning tool freely rotatable at the upper end of the screw.

Figure 15 is a diagram illustrating an implementation mode of the cleaning method according to the invention, including a close loop control.

Detailed description of the invention

The present invention will be described with respect to particular embodiments and with reference to the appended drawings, but the invention is not limited thereto. In the drawings, which are only schematic, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes. The dimensions and relative dimensions do not correspond to actual reductions to practice of the invention.

Figure 1A illustrates an aerosol-generating device 100 according to an embodiment of the present invention.

The device 100 comprises an outer body 2 of any adapted shape, housing a longitudinal heating cavity 10 (hereafter also named cavity) extending along a center or longitudinal axis Z1 defining a longitudinal direction Z.

The heating cavity 10 is delimited by a lateral wall 12 in a lateral direction Y orthogonal to the longitudinal direction Z and has a tubular shape with a constant, here circular, section (considered in a transversal plane X-Y orthogonal to the longitudinal direction Z).

The heating cavity 10 is provided with an opening 14 at one insertion or upper end 10a, and is adapted to receive at least part of the aerosol-generating article (not shown) inserted through said opening 14. The device 100 further includes a heating system 20 powered by an electrical power source 90 and configured to heat the aerosol-generating article received in the heating cavity 10, the heating system 20 and electrical power source 90 being housed in the outer body 2 of the device 100.

As illustrated, the heating system 20 may be an external heater including a heater body 22 in the form of a longitudinal metal sleeve surrounding the heating cavity 10, and a heating element 28, such as a thick or thin film comprising a layer of electrically insulating material and a layer of electrically conductive material outside or within the heater body 22.

In the particular example shown in figures 2 and 3, the heater body 22 has a cup shape, with a lateral tubular wall 23 and a bottom wall 24. The heating element 28 being provided outside said heater body 22, the lateral wall 23 here forms the lateral wall 12 of the heating cavity 10.

As shown in figure 2, the heater body 22 is received within a holder 80, typically made of high-temperature resistant plastic such as PEEK, having a transversal base 81 orthogonal to the longitudinal direction Z of the heating cavity 10 and holding means 82 such as longitudinal tongues upwardly protruding from the base 81 , configured to hold the heater body 22 for example by clamping.

Advantageously, the holding means 82 are configured to hold the heater body 22 at a distance from the base 81 , leaving an interstice between the heater body 22 and the base 81 which function will be described hereafter.

When an aerosol-generating article is inserted in the heating cavity 10 and the device 100 is actuated by the user, an electrical current is supplied to the heating element 28 by the electrical power source 90. The heating element 28 is heated, and the heat is transmitted by thermal conduction to the heater body 22 and consequently to the article surrounded by said heater body 22.

Upon heating, the aerosol-forming substance contained in the tobacco substrate of the article vaporises and creates a vapour that extracts nicotine and flavour components from said tobacco substrate.

Volatile compounds, aerosol, pieces of the aerosol-generating articles or external dust accumulate on the lateral wall 12 of the heating cavity 10. According to the invention, the aerosol-generating device 100 comprises an integrated cleaning tool 30 movable in the longitudinal direction Z and configured to rub said contamination materials on the lateral wall 12.

The cleaning tool 30 is provided with at least one cleaning member 40 extending laterally at a periphery of the tool 30 and configured to flexibly rub the lateral wall 12.

Several embodiments of said cleaning tool 30 will be described in more detail in the following description.

In a retracted position, the cleaning tool 30 forms a bottom surface of the heating cavity 10, as illustrated in figure 1A.

The movement of the cleaning tool 30 inside the heating cavity 10 is actuated by means of an actuator 60, for example a mechanical linear actuator of the screw-nut type.

The actuator 60 may be triggered based on a user’s command, for example trough a user’s button 92 provided on the device 100, and/or based on other parameters, such as for example a time period and/or a number of vaping sessions since last cleaning session and/or a level of contamination inside the cavity and/or a temperature of the heating system and/or a charging state of the battery 90 and/or a resistance or impedance at the lateral wall of the heating cavity.

The device 100 advantageously comprises a controlling unit 94, typically a microcontroller, configured to trigger the actuator 60 based on one or several parameters as mentioned above.

The controlling unit 94 is linked to the user’s button 92 (if any) and to the battery 90, from which it receives signals, and configured to operate both the actuator 60 and the heating system 20.

According to an advantageous arrangement, the device 100 may further be provided with at least one sensor 96 configured to measure at least one parameter representative of a level of contamination of the heating cavity 10, and send a corresponding signal to the controlling unit 94. The at least one sensor 96 may for example be configured to measure an electrical resistance or impedance, in particular an electrical resistance or impedance at the lateral wall 12. The dirt on the lateral wall 12 having another electrical resistance/impedance than the heater body 22, measuring such parameter allows estimating the dirtiness level on said lateral wall 12.

Cleaning may thus be controlled in a closed loop, depending on the actual needs, hence avoiding that the heating cavity 10 be cleaned too often or on the contrary not often enough.

A process flow diagram is provided in figure 15 and illustrates one possible implementation of the cleaning method according to the invention, operated in closed loop:

In a first step S1 , the controlling unit 94 checks whether a condition for processing to cleaning is satisfied, for example if the battery 90 is at least charged at 80% or in charge.

In a third step S2, a parameter representative of a dirtiness of the heating cavity 10 is measured.

In a fourth step S3, the measurement signal is filtered, digitalized and processed, typically by a firmware associated with the sensor 96.

In fifth step S4, the dirtiness level estimated by the firmware is transmitted to the controlling unit 94.

In a sixth step S5, the cleaning process is actuated by the controlling unit 94 based on the estimated dirtiness level.

In a seventh step S6, the user may be notified that the cleaning has been completed.

As an alternative, the cleaning may also be controlled in an opened loop, i.e. as programmed due to calibration. In such case, sensors 96 assessing contamination inside the cavity 10 may be omitted or used as a complement.

The automated cleaning control in closed or opened loop may also be complemented by a user’s command for cleaning. It is to be noted that the cleaning process as such might be adapted to the needs: for example, it may include moving the cleaning tool several times back and forth along the cavity, possibly at different speeds and/or with different temperatures in the heating cavity.

The actuator 60 according to a possible embodiment is illustrated in figures 2 and 3. The actuator 60 here comprises a motor 62, and a screw 64 translatable in the longitudinal direction Z by actuation of the motor 62. In the illustrated example, the screw 64 extends along a longitudinal axis Z2, coaxially with the heating cavity 10, and the cleaning tool 30 is solidary with the screw 62, for example fixed at the top end 64a thereof (figure 1 B), notably by a threaded connection 39 as will be described in more detail hereafter with reference to figure 5.

The screw 64 here goes through an opening 25 formed in the bottom wall 24 of the heater body 22 and is long enough to move the cleaning tool 30 up and down all along the heating cavity 10. A clearance 9 is required under the heating cavity 10, to receive the screw 64 in its retracted position.

The edges 26 of the bottom wall 24 of the heater body 22 around the screw opening 25 may advantageously be turned upwardly to prevent dirt to fall into inaccessible parts of the device 100. An additional silicone seal 27 may further be placed around opening 25, on a lower side of bottom wall 24, to prevent dirt from falling out.

In this first embodiment, the motor 62 is of the indirect-drive and off- centered type (axis Z3), and the actuator 60 comprises a reduction gearing 70 between the motor 62 and the screw 64, for transferring rotational movement to the screw 64. The reduction gearing 70 comprises meshing cogwheels, here two cogwheels 71 , 72, having together an overall transmission ratio less than 1 for decreasing the rotation speed and increasing the torque transmitted to the screw 64.

In the illustrated embodiment, the motor 62 is attached to the holder 80, in particular to a bottom side of base 81 , and its axis 63, which goes through said base 81 , is solidary with the first cogwheel 71 of smaller diameter. Due to the interstice between the heater body 22 and base 81 , the motor 62 is protected from possible overheating. The motor 62 is connected to the controlling unit 94 and receives electric power from the battery 90.

The first cogwheel 71 is secured at a top side of the base 81 with a cotter pin 73 to prevent getting loose. The first cogwheel 71 meshes with the second cogwheel 72 of larger diameter, hence transferring rotational movement of the motor axis 63 to said second cogwheel 72.

The second cogwheel 72 has a gearing portion 74 located at a top side of the base 81 and meshing with the first cogwheel 71 , and a central axis 75 provided with a threaded hole 76 configured to receive the screw 64 in threaded engagement. The second cogwheel 72 forms a so-called nut of the mechanical actuator 60.

With such arrangement, a rotational movement of the second cogwheel 72 induces a longitudinal movement of the screw 64 and so of the cleaning tool 30 which is solidary with the screw 64.

In the particular illustrated example, the central axis 75 of the second cogwheel 72 is mounted in a through hole 83 of the base 81 .

According to a non-illustrated embodiment, a bearing could further be over-moulded to said through hole 83 of the holder 80 to reduce the friction between the axis of cogwheel 72 and the base 81 .

A small latch 77 may further be placed below the second cogwheel 72 and the holder 80 to fix the cogwheel 72 in longitudinal position, as shown in figures 2 and 3.

According to a non-illustrated embodiment, the rigidity of the screw 64 may further be enhanced by providing an additional holder at the bottom thereof.

The reduction gears such as cogwheels 71 , 72 may be manufactured from temp-resistant plastic, such as PolyEtherEtherKetone (PEEK) or from metals. The screw 64 may be made from metals, preferably stainless steel.

Once the user presses the actuation button 92, the motor 62 starts moving the screw 64 up. As the screw 64 rotates and goes up, the cleaning tool 30 is being pushed up. At its bottom end, the screw 64 is advantageously provided with a hard stop 65 preventing it from falling out in case the motor 62 doesn’t stop in time.

The actuator 60 described with reference to figures 2 and 3 shall not be considered limitative and figure 4 illustrates an actuator 60 including a motor 62 having its axis Z3 aligned with the screw axis Z2. With such arrangement, the motor 62 may be a direct drive motor 62, with the nut being integral therewith. The actuator 60 with direct-drive motor is more compact and requires no mechanical transmission elements such as gearings. According to another embodiment, the motor 62 may be of the indirect drive-type.

Furthermore, although in the above-described embodiment the cleaning tool 30 is rotatably mounted in the cavity 10, which in particular is suitable with a heating cavity 10 of circular section, the cleaning tool 30 may also be fixed with one degree of freedom to move longitudinally without rotating, notably for cavities having non-circular sections. In such case, the screw 64 may be fixed in the longitudinal direction Z1 and the cleaning tool 30 may be configured to move along the screw 64 upon rotation thereof. The screw may in particular be offset with respect to the longitudinal axis Z1 of the heating cavity 10. Or, according to another embodiment illustrated in figure 14, the tool 30 may be supported in a free rotatable manner at the end of the longitudinally movable screw, for example by at least one ball bearing 54. In the illustrated example, the ball bearing 54 comprises a top supporting element 55 forming a hub 56 solidary with the top end 64a of the screw 64 and a shaft 57 solidary with the tool body 31 . A reverse arrangement is also possible.

Examples of cleaning tools 30 and their cleaning members 40 will now be described with reference to figures 5 to 13.

A cleaning tool 30 has typically a central cleaning body 31 and one or several cleaning members protruding from the periphery of said cleaning body 31.

The tool body 31 has a body axis Z4 which, after assembly, is parallel and preferably aligned with the longitudinal axis Z1 of the heating cavity 10. As illustrated respectively in figures 5 to 7 and in figure 14 already mentioned hereabove, the cleaning members 40 may be removably attached to the tool body 31 .

In such embodiments, the cleaning members 40 may form distal parts of cleaning modules 46 attached to the body 31 at their proximal end.

In the embodiment of figure 5 for example, the body 31 includes an upper body part 32 and a lower body part 34 aligned along said axis Z4.

The lower body part 34 is securely attached to the top end 64a of the screw 64 by a threaded connection 39, which arrangement is compatible notably with an actuator of the type described hereabove with reference to figures 2 and 3. This, however, shall not be considered limiting, as already indicated hereabove.

In the example, the upper and lower body parts 32, 34 are configured to be threadedly secured to each other.

On its upper side opposite to threaded connection 39, the lower body part 34 is provided with a threaded hole 35 and with a first contact surface 34a, here substantially orthogonal to the body axis Z4.

The upper body part 32, on the other hand, is provided with a protruding threaded rod 33 at its lower side, said rod 33 being configured to threadedly cooperate with the corresponding hole 35 of the lower body part 34. Around said rod 33, the upper body part 32 is further provided with a second contact surface 32a, here substantially orthogonal to the body axis Z4.

When both parts 32, 34 are firmly secured to each other, the first and second contact surfaces 32a, 34a act as clamping jaws for securing the cleaning module(s) 46 therebetween. If needed, the cleaning module(s) may be easily detached by disconnecting the upper and lower body parts 32, 34. Any other means adapted to removably secure cleaning members to the cleaning body may be envisaged as an alternative.

It has to be mentioned that the removable arrangement of the cleaning members 40 is also not limitative and the cleaning members 40 and cleaning body 31 may well be integrally formed (molded or injected), with the cleaning members 40 protruding laterally from the central cleaning body 31 . Figure 13 for example illustrates a cleaning tool 30 with non-detachable cleaning members 40.

As illustrated in figures 5 and 6, the cleaning tool 30 advantageously comprises at least one air channel 38 arranged on both a lateral side and an upper side thereof.

The air channel 38 is configured to allow a passage of air from a lateral side of the cleaning tool 30 towards an upper side thereof. Hence the cleaning tool 30 allows the air to flow towards the tip of the tobacco stick, which is necessary for vaping efficiency. The number or arrangement of the air channel(s) 38 on the upper side of the tool body 31 may be adapted to the needs. In figure 4 for example, the body 31 is provided with four intersected air channels 38 forming a cross. In figure 6, the body 31 is provided with eight intersected air channels 38 with two adjacent channels forming an angle of about 45°.

In the embodiment illustrated in figures 7 and 8, the cleaning tool 30 comprises several cleaning members 40 juxtaposed tightly next to each other all around its periphery.

The juxtaposed cleaning members 40 are narrow elongated beams forming teeth of a cleaning comb 42, with each cleaning member 40 having a main axis Z5 extending in a lateral direction.

Each cleaning member 40 protruding laterally from the cleaning body 31 has preferably a length I, measured along its main axis Z5, comprised between 0.1 and 1 mm.

The section of a cleaning member 40, orthogonally to its main axis Z5, may be circular, rectangular, or of any other shape adapted to ensure flexibility in consideration of the length I of said cleaning member.

A thickness h of each cleaning member 40, measured in the longitudinal direction, may preferably be comprised between 0.01 and 0.5 mm, preferably between 0.05 and 0.2 mm. More particularly, a maximum dimension of the cleaning member 40 measured in a plane orthogonal to its main axis Z5 may be comprised between 0.01 and 0.5 mm, preferably between 0.05 and 0.2 mm.

As an example, each cleaning member may be inscribed in an angular sector having an angle 01 of less than 1 °, even less than 0.5° around the longitudinal axis Z1 (body axis Z4).

In a removable arrangement as illustrated in figure 5, each cleaning member 40 may be part of one individual element or module 46, attached to the tool body 31 independently from the others.

According to a preferable embodiment however, a plurality of teeth 40, in particular all teeth 40, may be joined together to form one single-piece cleaning module 46.

Such cleaning module may for example be formed from a disk-shaped sheet of metal, e.g., stainless steel or titanium, centrally perforated and etched at its periphery to form the teeth 40.

As illustrated in figure 8, the cleaning members 40 may also be at least partially coated, in particular at their free end 40a, to enhance the rubbing effect or otherwise improve the cleaning. The coating 44 may be based on or made of PTFE or silicon or any other adapted material. It may be applied for example by dipping, dipping and centrifugation, or other coating techniques.

Figure 9 illustrates another embodiment where a cleaning module 46 is formed by a folded wire 44, notably a folded metal wire with each externally oriented bend part of the wire forming a cleaning member 40 at the periphery of the cleaning tool 30. The so formed cleaning members 40, tightly juxtaposed, form a cleaning comb 42 similar to that of figure 7, configured to brush the lateral wall 12 of the heating cavity 10.

Figure 10 illustrates a cleaning tool 30 according to still another embodiment, where the cleaning member 40 is a flexible disk-shaped spatula, perforated at its center to allow passage of the fixing rod 33. Although the preceding figures illustrate one single cleaning layer L comprising one cleaning zone 50 extending all around the cleaning tool 30, this shall not be considered limiting.

In particular, as illustrated in figure 11 , the cleaning tool 30 may also comprise, at its periphery and seen in transversal projection, at least one free zone 52 with no cleaning member 40, the or each free zone 52 extending on an angular sector having an angle 02 of at least 35°, preferably of at least 70°, around the longitudinal axis

More particularly, the cleaning tool 30 may comprise, along its periphery, an alternance of cleaning zones 50 and free zones 52.

In such case, it may be relied on the rotation of the cleaning tool 30 to swipe the whole lateral wall 12. The thickness of the cleaning zones 50 in the longitudinal direction Z should then be designed according to the pitch of the screw threads.

As illustrated, a cleaning member 40 or a plurality of juxtaposed cleaning members 40 are typically defined in a transversal plane or a plane inclined with respect to a transversal plane, forming a so-called cleaning layer L.

Although the cleaning tools described hereabove include one single cleaning layer L, the cleaning tool 30 may also comprise several cleaning layers L1 , L2 superimposed in the longitudinal direction, each layer L1 , L2 including one or several cleaning members 40 and/or zones 50, as illustrated in figure 12.

Superimposed cleaning layers L1 , L2 may be stacked directly one on the other to provide thicker cleaning zone(s) 50, or the different cleaning layers may be spaced apart by spacers 48 as illustrated in figure 12.

Figure 13 illustrates a cleaning tool 30 according to a further embodiment.

The tool 30 is here provided with a collecting cup 37 located under the cleaning zone(s) 50, to collect debris brushed by the cleaning member(s) 40 as the tool 30 is moved in the cavity 10. This is aimed at avoiding debris accumulation in the bottom of the heating cavity 10 over time and facilitate evacuation thereof by tilting down the device 100, preferably when the screw 64 is fully extended in the heating cavity 10 (i.e. the tool 30 is in its most deployed position as illustrated in figure 1 B). The cleaning members 40 and the collecting cup 37 may be integrally formed (molded or injected) with the tool body 31 as illustrated in the figure. As an alternative however, they may be removably attached together and/or fixed to the tool body 31 in any adapted way, for example by press fit/screw/magnet engagement.