Patent Description:
Flame producing assemblies such as a conventional cigarette lighters comprise a fuel source of pressurized and liquidized butane. Plastic materials used to provide a safe enclosure for the liquidized butane are often opaque. This means that the user of a conventional cigarette lighter cannot observe the amount of fuel remaining inside a conventional cigarette lighter by visual inspection of the cigarette lighter. This leads to conventional cigarette lighters being disposed of before the liquid fuel supply has been fully exhausted.

<CIT> discusses a device for driving a pump in a combustion device.

<CIT> discusses a fuel level indicator for a cigarette lighter.

<CIT> discusses a paintball marker comprising a CO2 liquid level indicator.

The performance of flame producing devices such as cigarette lighters can, therefore, be further improved.

According to a first aspect of the invention, there is provided a flame producing assembly. The flame producing assembly comprises a sealed body comprising a proximal and a distal end aligned on a longitudinal axis, wherein the sealed body comprises a void and a visible portion, a fuel supply comprising liquid fuel isolated within the sealed body, a fuel release member enabling a controllable release of the fuel supply in gaseous form from the sealed body, and a fuel indicator configured to indicate a remaining amount of liquid fuel contained in the sealed body to a user of the flame producing assembly. At least a portion of the fuel indicator is capable of changing appearance when in proximity to a magnetic field. The flame producing assembly further comprises a level tracking member comprising at least one magnet supported by a buoyant member. The at least one magnet is configured to apply a magnetic field to the fuel indicator, thereby causing the fuel indicator to indicate an amount of liquid fuel remaining in the sealed body to a user.

According to this aspect, accurate visualisation of the fuel consumed by a flame assembly, or the fuel remaining, is possible even if the flame producing assembly is opaque or visibility of the fuel inside the flame producing assembly is not possible. Furthermore, it may be difficult for users to view the amount of fuel remaining even with translucent bodies. Use of a fuel level indicator as discussed herein can improve visibility in a flame producing assembly having translucent and opaque flame producing assembly bodies. Furthermore, flame producing assemblies (such as cigarette lighters) substantially as described herein are not prematurely disposed of by users, thus reducing plastic waste over time. Furthermore, the lighters that are disposed of can be guaranteed to have exhausted their liquid fuel supply, thus improving the effect on the environment. Using an appropriate scale, the communication of an approximate number of flame generating actuations of the lighter left can be communicated to a user. As a passive measure of the remaining fuel, the user does not need to activate the fuel level indication system, and no external electronics are required, because the magnet and fuel indicator capable of changing colour in the influence of a magnetic field is always active without requiring electricity.

According to a second aspect of the invention, there is provided a method for using a flame producing assembly, comprising:.

According to the present disclosure, the term "flame producing assembly" may refer to a cigarette lighter, cigar lighter, domestic gas ring lighter, butane gas cylinder (for example, as used in a camping stove or Barbeque), a gas-powered soldering iron, or a utility blowtorch for paint stripping, as examples.

According to the present disclosure, the term "proximal" refers to the end of a substantially longitudinal body such as a flame producing assembly that, in use, is closer to an element being lit by the flame producing assembly, such as a cigarette. The term "distal" refers to the end of a substantially longitudinal body such as a flame producing assembly that, in use, is further from element being lit by the flame producing assembly than the "proximal" portion.

Other characteristics will be apparent from the accompanying drawings, which form a part of this disclosure. The drawings are intended to further explain the present disclosure and to enable a person skilled in the art to practice it. However, the drawings are intended as nonlimiting examples. Common reference numerals on different figures indicate like or similar features.

<FIG> illustrates a standard cigarette lighter.

Conventional cigarette lighters (flame producing assemblies) are filled with pressurised butane gas in liquid form. The basic aspects of a standard cigarette lighter <NUM> are illustrated in <FIG>. The standard cigarette lighter <NUM> comprises a sealed body <NUM> having a proximal end <NUM> and a distal end <NUM>. The standard cigarette lighter <NUM> is disposed between the proximal end <NUM> and the distal end <NUM> along a longitudinal axis L. At the proximal end <NUM> of the standard cigarette lighter <NUM>, an ignition control portion <NUM> is collocated with, and operably connected to, a fuel release assembly <NUM>. A wind guard <NUM> is usually provided in proximity to the fuel release assembly <NUM> to prevent the rapid extinguishment of the flame by strong wind incident on the lighter <NUM>. A sparking assembly <NUM> comprises a striking wheel 23a held in contact against a sparking member 23b by a confined spring 23c. The sparking member 23b may, for example, be a portion of flint.

The fuel release assembly <NUM> may comprise, for example, a sealed body outlet <NUM> and a nozzle member <NUM>. The nozzle member <NUM> is attached to a first end of actuation lever <NUM>. The nozzle member <NUM> is arranged to move substantially in parallel to the longitudinal axis L of the lighter <NUM> upon movement of the end of the actuation lever <NUM> that holds the nozzle member <NUM> towards the proximal end <NUM>. As the nozzle member <NUM> moves away from the sealed body outlet <NUM>, a valve seat (for example) is exposed, enabling a pressurised gas within the void of the sealed body <NUM> to exit the sealed body <NUM> via the sealed body outlet <NUM> and through the nozzle member <NUM>.

The ignition control portion <NUM> comprises a spring-biased ignition button <NUM> actuatable by a user of the lighter <NUM>. The ignition button <NUM> is operably coupled to a second end of the actuation lever <NUM>. When the ignition button <NUM> is pressed down by a user (along the direction of the longitudinal axis L from the proximal end <NUM> to the distal end <NUM>, the second end of the actuation lever <NUM> is pressed downwards, and thus by the action of a fulcrum (not shown), the first end of the actuation lever <NUM> moves substantially along the longitudinal direction in the direction from the distal end <NUM> to the proximal end <NUM>. A protruding lip of the nozzle member <NUM> captures a portion of the first end of the actuation lever <NUM> during this motion, typically causing the nozzle member to be translated substantially along the longitudinal direction in the direction from the distal end <NUM> to the proximal end <NUM> with the first end of the actuation lever <NUM>. This uncovers the outlet <NUM> of the sealed body <NUM>, enabling gaseous fuel (for example, from compressed isobutane) to escape to the portion of the nozzle member <NUM> enclosed by wind guard <NUM>.

Contemporaneously with the action described in the previous paragraph, during conventional operation of the standard cigarette lighter <NUM>, a user manipulates the striking wheel 23a such that a spark is generated in proximity to the nozzle member <NUM> enclosed by wind guard <NUM>. The presence of a gaseous fuel in proximity to the nozzle member <NUM> implies that the spark will light the gaseous fuel to produce a flame suitable for lighting a cigarette, for example. The flame remains until the user removes the force from the ignition button <NUM>, or until the fuel supply is exhausted.

When a user removes the force from the ignition button <NUM> of the ignition control portion <NUM>, the previously described action is reversed by a resilient member (not shown), for example a biasing spring of the ignition control portion, thus causing the sealed body outlet <NUM> to be closed.

In view of the foregoing discussion, typically the body of a standard cigarette lighter <NUM> is often compact, durable, and unbreakable in order to maintain the required gas liquification pressures safely. Therefore, in high quality lighters, special grade opaque plastic materials are used that possess the required mechanical properties. The grade of plastic used for the body of the lighter being non-transparent makes it impossible for a user to see, or to estimate, the level of the liquid fuel quantity remaining inside the plastic container. Therefore, a regular lighter user is not able to verify, easily and accurately, if the lighter contains enough fuel to last for a desired period of time.

As discussed herein, a lighter user is able, by means of a special indicator, to estimate the approximate amount of fuel or number of flames left by the use of a fuel level indicator.

<FIG> illustrates a general external view comprising a partial internal cutaway view of a flame producing assembly <NUM> with a magnetic indicator according to aspects discussed herein. Reference numerals denoting similar elements of a flame producing assembly <NUM> as introduced in <FIG> are repeated. This is for the purpose of example only. A skilled person will understand that a level tracking member comprising a magnet, and a fuel indicator capable of indicating a remaining amount of fuel when in proximity to a magnetic field, as described herein, may be applied to a wide range of flame producing articles, without limitation to the example design illustrated in the Figures.

In general, the present application concerns a flame producing assembly <NUM> having a sealed body <NUM> containing pressurised liquid fuel. The flame producing assembly <NUM> illustrated in <FIG> demonstrates the internal position of a level tracking member <NUM> in relation to the position of a fuel indicator using the sealed body cutaway view <NUM>. In <FIG>, the void of the sealed body <NUM> is approximately half filled with liquid pressurised fuel. The level tracking member <NUM> moves in a longitudinal direction L according to the level of the liquid pressurised fuel in the sealed body <NUM>. The level tracking member <NUM> comprises a magnet and also comprises a buoyant member enabling the level tracking member <NUM> to be buoyant on, or close to, the surface of the remaining liquid pressurised fuel. The level tracking member <NUM> moves along a path defined by the shape and/or path of confinement member <NUM>, which in this example is illustrated as a cylinder having at least one fluid connection to the sealed body <NUM>. As shown in an inset of <FIG>, an example of a buoyant level tracking member <NUM> is a magnet <NUM> having a magnetic axis M fixed to one or more buoyant members <NUM>.

According to embodiments, the fuel indicator <NUM> is configured to display feedback to the user of the approximate amount of fuel remaining in the sealed body via one or more text or indicator labels on a visible surface of the flame producing assembly <NUM>, and/or via a change in colour of the fuel indicator <NUM>.

According to embodiments, the fuel indicator <NUM> indicates the current amount or level of fuel remaining relative to the proximal <NUM> and distal ends <NUM> of the sealed body <NUM> to a user.

A visible portion of the sealed body <NUM> comprises a fuel indicator <NUM>, for example, a magnetic indication strip or magnetochromic liquid containing member. The fuel indicator <NUM> is capable of changing appearance when in proximity to a magnetic field. A magnetic field of the magnet <NUM> therefore changes the appearance of the visible portion of the sealed body <NUM> to provide a region of maximum appearance change <NUM> of the fuel indicator <NUM>. A user may place the flame producing assembly <NUM> such that its longitudinal axis L is substantially parallel to a vertical direction, and in this case, the region of maximum appearance change <NUM> of the fuel indicator <NUM> may be read by a user as corresponding to a remaining amount of pressurised liquid fuel inside the sealed body <NUM>, therefore enabling the user to estimate the remaining amount of fuel inside the sealed body <NUM>. In examples, appearance change implies a change in colour of at least a portion of the fuel indicator. Of course, more advanced patterning of the substance of the fuel indicator <NUM> may be provided to enable a range of lines, textual display features, icons, motifs, and the like based on the remaining amount of pressurised liquid fuel in the sealed chamber <NUM>.

In other words, the flame producing assembly <NUM> provides a passive system for estimating the approximate amount of fuel or number of flames left. In examples, at least one magnet <NUM> passively follows the level of pressurised liquid fuel in the flame producing assembly <NUM>. A passive user indication system that communicates the amount of fuel, and/or number of flames remaining, to the user via at least one magnetic indication member located on the outer surface of the flame producing assembly <NUM> is provided.

In view of this general operational principle, a specific example of a flame producing assembly will now be discussed, although a skilled person will appreciate that many variations exist.

According to a first aspect of the invention, there is provided a flame producing assembly <NUM>. The flame producing assembly comprises a sealed body <NUM> comprising a proximal <NUM> and a distal <NUM> end aligned on a longitudinal axis L, wherein the sealed body comprises a void. The flame producing assembly <NUM> comprises a fuel supply <NUM> (see <FIG>) comprising liquid fuel accommodated in the void within the sealed body, and a fuel release assembly <NUM> enabling a controllable release of the fuel supply in gaseous form from the sealed body. The flame producing assembly <NUM> further comprises a fuel indicator <NUM> configured to indicate a remaining amount of liquid fuel contained in the sealed body to a user of the flame producing assembly, wherein at least a portion of the fuel indicator is capable of changing appearance when in proximity to a magnetic field, and a level tracking member <NUM> comprising at least one magnet <NUM> supported by a buoyant member <NUM>. The at least one magnet <NUM> is configured to apply a magnetic field to the fuel indicator <NUM>, thus causing the fuel indicator <NUM> to indicate an amount of liquid fuel remaining in the sealed body <NUM> to a user. In embodiments, the level tracking member <NUM> comprises one magnet. In embodiments, the level tracking member <NUM> comprises a plurality of magnets.

<FIG> schematically illustrates a longitudinal section of a flame producing assembly <NUM> lacking the level tracking member <NUM> for illustrative purposes.

The flame producing assembly <NUM> resembles the cigarette lighter <NUM>, and like reference numerals as compared to those of <FIG> denote like or similar parts. The flame producing assembly <NUM> further comprises a fuel indicator <NUM> disposed along a portion of the outer (visible) surface of the sealed body <NUM>. In examples, the fuel indicator <NUM> extends along the entirety of the surface of the sealed body <NUM>, as illustrated in <FIG>. In examples, the fuel indicator extends along a portion of the surface of the sealed body. The fuel indicator <NUM> is capable of changing appearance when in proximity to a magnetic field. The level tracking member <NUM> comprises at least one magnet <NUM> supported by a buoyant member <NUM> (not illustrated in <FIG>). In embodiments, the level tracking member <NUM> is confined by a confinement member <NUM> provided in this example as a linear separator comprising first 41a and second 41b liquid flow apertures in fluid communication with the main void of the sealed body <NUM>. Therefore, the confinement member <NUM> provides a track along which the level tracking member <NUM> may freely float whilst in proximity to the fuel indicator <NUM>. The magnetic field created by at least one magnet <NUM> may thus be exposed to the fuel indicator <NUM> along the longitudinal direction L in a controlled manner, as the liquid fuel depletes from the sealed body <NUM>.

<FIG> further schematically illustrates the longitudinal section of the flame producing device according to <FIG>.

The void of the sealed body <NUM> is half-filled with pressurised liquid fuel in the illustration. A level tracking member <NUM> comprising a buoyant member <NUM> and a magnet <NUM> moves with the level of the pressurised liquid fuel in the sealed body <NUM> because the interior of confinement member <NUM> housing the level tracking member <NUM> is in fluid communication with the main volume of the sealed body <NUM> via at least liquid flow apertures 41b and 41a, such that the fuel indicator <NUM> changes appearance at location X. This corresponds to a point of maximum change in magnetic flux incident on the surface of the fuel indicator <NUM>.

According to embodiments, the fuel indicator <NUM> comprises at least one sealed body comprising a liquid magnetochromic ink. The fuel indicator <NUM> may comprise a liquid magnetochromic ink. Therefore, fuel indicator <NUM> may be a pouch, cavity or thin body disposed proximate to the external surface of the sealed body <NUM> to enable changes in the liquid magnetochromic ink to be perceived by the user.

According to embodiments, the void within the sealed body <NUM> is divided such that the sealed body comprises a first chamber 12a and a second chamber 12b, wherein the second chamber is aligned in parallel with the longitudinal axis, wherein the second chamber is in fluidic communication with the first chamber, and wherein the level tracking member <NUM> is confined to the second chamber and a boundary of the second chamber is proximate to the fuel indicator <NUM>.

For example, in <FIG> the confinement member <NUM> terminates with a first liquid flow aperture 41a towards the proximal end <NUM> of the flame producing assembly <NUM>, and a second liquid flow aperture 41b towards the distal end <NUM> of the flame producing assembly <NUM>. In this case, the confinement member <NUM> is provided as a divider inside the sealed body <NUM>. The divider may be integrally formed with the same material as the remainder of the sealed body <NUM>, to form a tube-like second chamber 12b (as also illustrated in <FIG>) for the level tracking member <NUM> to move within.

According to embodiments, the interior of the sealed body <NUM> comprises at least one confinement member <NUM> to confine the path of the level tracking member within the sealed body, for example in a path that is aligned in parallel to the longitudinal axis of the flame producing assembly <NUM>.

In embodiments (not illustrated), the divider inside the sealed body <NUM> forming the confinement member <NUM> does not need to form a tube inside the sealed body <NUM>. For example, a rear inner surface of the sealed body <NUM> may be provided with a first elongate linear protrusion. A front inner surface of the sealed body <NUM> may be provided with a second elongate linear protrusion facing the first elongate linear protrusion, but not sealably abutting the first elongate linear protrusion so as to form a seal. In this case, a linear gap running along substantially the entire longitudinal length of the flame producing assembly <NUM> forms the fluidic connection to the first chamber 12a of the sealed body <NUM>. The first and second elongate linear protrusions form a guide that the level tracking member <NUM> may move along according to the remaining amount of liquid fuel in the first chamber 12a of the sealed body <NUM>.

In embodiments (not illustrated), the confinement member <NUM> may be provided as a plastic or metal guide wire. In operation, the level tracking member <NUM> moves in a predefined path according to the placement of the plastic or metal guide wire along with the level of remaining fuel in the sealed body <NUM>.

In embodiments (not illustrated), the confinement member <NUM> may be provided by one or more blocking members or pegs positioned in the sealed body <NUM> between a front and rear face of the flame producing assembly <NUM>. In operation, the level tracking member <NUM> moves in a predefined path bounded by the one or more detents or pegs according to the level of remaining fuel in the sealed body <NUM>.

According to embodiments, an internal surface of the second chamber 12b comprises a low friction coating 42a, 42b configured to facilitate the movement of the level tracking member <NUM> in a direction substantially parallel to the longitudinal axis L. A skilled person will appreciate that a plastic forming the body of the sealed member <NUM> such as Delrin (TM) has a relatively low coefficient of friction. In embodiments, at least a portion of an internal surface of the second chamber 12b may be coated with a low-friction coating such as Teflon (TM) to facilitate the movement of the level tracking member <NUM>, and/or to prevent the level tracking member <NUM> from becoming stuck against the side of the confinement member <NUM>. In embodiments, the confinement member <NUM> is a tube having a square, rectangular, or circular cross-section.

In embodiments, the confinement member <NUM> is disposed so that the level tracking member <NUM> moves in a substantially longitudinal direction proximate to the wall of the sealed body <NUM>. This maximises the magnetic field incident on the magnetically active fuel indicator.

According to embodiments, the at least one magnet <NUM> comprises a rare-earth material, alnico, or ferrite. The at least one magnet <NUM> is configured to produce a constant magnetic field. The at least one magnet <NUM> is a permanent magnet. The dimensions of the at least one magnet are designed in cooperation with the buoyant member <NUM> of the level tracking member <NUM>, and may have a specific shape and type depending on the dimensions and location of the second chamber 12b and/or confinement member <NUM> within the flame producing assembly.

In embodiments, at least one magnet <NUM> comprises a magnetic axis M (north-south axis) aligned substantially in parallel to the longitudinal axis L of the flame producing assembly <NUM>. In embodiments, at least one magnet <NUM> comprises a magnetic axis M (north-south axis) aligned substantially perpendicular to the longitudinal axis L of the flame producing assembly <NUM>.

The shape of the at least one magnet <NUM> may be, for example, spherical, cylindrical, tubular, cubic, or conical. Where more than one magnet <NUM> is provided, each magnet may have a different shape.

The mass of the at least one magnet <NUM> may be, for example, in the range <NUM> to <NUM> grams. For example, neodymium (NdFeB) has a density of <NUM> grams per cubic centimetre. In examples, the at least one magnet is an N40 magnet. In examples, an N40 neodymium magnet has a remanence (Br) of up to <NUM>,<NUM> mT.

In examples, the at least one magnet <NUM> has a remanence (Br) of between <NUM> and <NUM>,<NUM> mT. In examples, the at least one magnet <NUM> has a remanence (Br) of between <NUM>,<NUM> and <NUM>,<NUM> mT.

In examples, the at least one magnet <NUM> may be coated with a coating, such as Ni-Cu-Ni (Nickel-Copper-Nickel), or PTFE ("Teflon", TM). In particular, a Teflon coating may improve the smoothness of the motion of the at least one magnet <NUM> as it moves within the second chamber 12b of the sealed body <NUM>.

According to embodiments, the liquid fuel is selected from: methane, acetylene, propane, propylene, hydrogen, or isobutane, or combinations thereof.

According to embodiments, the flame producing assembly <NUM> is a lighter, more specifically a cigarette lighter or a utility lighter.

According to embodiments, the level tracking member <NUM> is configured to move parallel to the longitudinal axis L of the sealed body <NUM> when the longitudinal axis L is aligned vertically, as illustrated in <FIG> and <FIG>, for example.

According to embodiments, the effective density of the level tracking member is less than the density of the liquid fuel comprised in the sealed body. Effective density is, for example, the average density of a member comprising a number of materials of different density averaged over unit space.

According to embodiments, the buoyant member <NUM> is a buoyant capsule or a porous raft configured to support the at least one magnet.

According to embodiments, the buoyant member <NUM> is configured to translate the at least one magnet <NUM> from a first position 30a to a second position 30b relative to the longitudinal axis as the amount of the liquid fuel in the sealed body <NUM> decreases.

According to embodiments, the level tracking member <NUM> is configured to float freely within the sealed body <NUM>. A major axis of the buoyant member <NUM> is, for example, between <NUM>% and <NUM>% in length compared to a greatest internal dimension of the sealed body <NUM> along a plane orthogonal to the longitudinal axis L of the flame producing assembly <NUM>. In other words, the level tracking member <NUM> may be a float that is only constrained by the walls of the sealed body <NUM>. According to this embodiment, a confinement member <NUM> is not required, because the entire sealed body <NUM> performs the role of the confinement member <NUM>.

Therefore, the level tracking member <NUM> (magnet floating mechanism) is configured to provide the buoyancy required by the at least one magnet <NUM> to float on the pressurized liquid fuel. The density of liquid butane, for example, is approximately <NUM> per cubic metre. To enable the magnet to follow the level of the pressurized liquid fuel, the level tracking member <NUM> requires a lower effective density than the pressurized liquid fuel.

To provide this buoyancy, the level tracking member <NUM> may comprise, for example, a plastic hollow airtight assembly that encapsulates or is attached to the at least one magnet <NUM>, and is configured to withstand the pressure of the pressurized liquid fuel and its chemical properties.

According to embodiments, the level tracking member <NUM> may comprise, for example, a porous material such as an open cell foam, or a closed cell foam, capable of increasing the effective surface area of the at least one magnet <NUM>, enabling it to float on the liquid fuel.

According to embodiments, the level tracking member <NUM> may comprise an unattached item of low density material (such as a closed cell foam or a float) as the buoyant member, supporting a loose magnet <NUM>. According to embodiments, the level tracking member <NUM> may comprise a hollow magnet <NUM> sealably enclosing a void containing a gas, where the gas provides buoyancy to the magnet <NUM>.

According to examples, the at least one magnet <NUM> may be partially or fully supported by a spring or resilient member (not illustrated) to offset the weight of the magnet. In this case, the required buoyancy, and thus size, of the buoyant member <NUM> may be reduced.

According to embodiments, the fuel indicator <NUM> is disposed along a portion of the external surface of the sealed body <NUM>. The fuel indicator <NUM> may be configured to appear to a user of the flame producing assembly <NUM> as a graphical indication which can provide an estimate to the user of the number of flames left based on the level of fuel remaining inside the sealed chamber <NUM>. In embodiments, the fuel indicator <NUM> has a scale (for example, applied to the magnetically active material using a black ink, for example) indicating a plurality of segments, so that each increment indicates an approximate number of flames left. For example, if the fuel indicator <NUM> has a length of <NUM>, and a fuel-filled flame producing assembly <NUM> can provide approximately <NUM> ignitions, the fuel indicator <NUM> may indicate a visual change <NUM> along the visible surface of the fuel indicator <NUM>, depicting that the flame producing assembly <NUM> has approximately <NUM> ignitions remaining.

According to embodiments, the fuel indicator <NUM> is distributed along at least a portion of an outer surface of the flame producing assembly, and a magnetic axis M between north pole and south pole of the at least one magnet <NUM> is aligned substantially orthogonally to the longitudinal axis, such that a component of magnetic flux intercepted by the fuel indicator is substantially maximised.

Such an arrangement facilitates clearer indication of the amount of remaining fuel on a magnetically active fuel indicator <NUM>, magnetically active fuel indicator <NUM> is stimulated by stronger magnetic field. This may enable a smaller magnet to be used in the confinement member <NUM>, and thereby reduces the size of buoyant member <NUM> required. Furthermore, such an arrangement may reduce the magnitude of magnetic fields directed from the at least one magnet <NUM> towards metallic components typically located at the proximal end <NUM> of a flame producing assembly <NUM>, such as the wind guard <NUM> or the ignition control portion <NUM>.

<FIG> schematically illustrates a longitudinal section of an alternative flame producing device according to aspects discussed herein.

According to an embodiment, the internal surface of the second chamber 12b is aligned to form an internal angle of A degrees with the longitudinal axis L of the flame producing assembly of between <NUM>° and <NUM>°, and is thus configured to vary a separation distance z between the level tracking member <NUM> and the fuel indicator <NUM> as the amount of fuel in the sealed body changes, to provide a corresponding variation of magnetic flux intercepted by the fuel indicator.

The arrangement of <FIG> is similar to those discussed above, except for the fact that the second chamber 12b (and/or its associated confinement member <NUM>) is now arranged at an offset angle A° from the perpendicular to the longitudinal axis L of the flame producing assembly <NUM>. For example, the offset angle may be <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, or <NUM>°. The second chamber 12b comprises at least one liquid flow aperture ensuring that the second chamber 12b is in fluidic communication with the first chamber 12a.

As the fuel level in the first chamber 12a declines, in use, the level tracking member <NUM> moves down the confinement member <NUM> and approaches the distal end <NUM> of the flame producing assembly. Because the confinement member <NUM> is arranged at a non-zero angle, for each reduction in the level of fuel in the sealed chamber <NUM>, the level tracking member <NUM> moves laterally away from the fuel indicator <NUM> by a distance z. Thus, the at least one magnet <NUM> comprised on the level tracking member <NUM> may exert a progressively weaker magnetic flux on the fuel indicator <NUM> as the fuel level reduces. This may be used as part of an optical feedback motif to a user denoting a fading colour or icon that implies a loss of remaining fuel duration, for example.

<FIG>) schematically illustrate aspects of a magnetochromic display according to aspects discussed herein.

<FIG>) illustrates a fuel indicator <NUM> in the form of a strip of magnetochromic material that can be applied to the external surface of a flame producing assembly. This form of fuel indicator <NUM> may utilize solid magnetochromic materials such as magnetochromic polymer, or magnetochromic viewing film.

<FIG>) illustrates a fuel indicator in the form of a cartridge disposed along the portion of the wall of a sealed body <NUM> of a flame producing assembly. A longitudinal groove or depression formed in the wall of a sealed body <NUM>, for example, may be covered by a translucent or clear member 25a. The void formed thereby may be filled with a liquid magnetochromic material and sealed. Therefore, as a magnet moves in proximity to the liquid magnetochromic material, a user may observe a change in appearance through the translucent or clear member 25a. The width of the translucent or clear member 25a, and/or the longitudinal groove or depression, may vary in the longitudinal direction. For example, the longitudinal groove or depression may have a greater width towards the proximal end <NUM> of the flame producing assembly, disappearing to a point towards the distal end <NUM> of the flame producing assembly <NUM>. This is another example of an optical motif that communicates to the user that the fuel comprised in the sealed body is becoming scarce. In an example, the translucent or clear member 25a may comprise an optical filter. The optical filter may vary in colour along the longitudinal dimension of the flame producing assembly. In an example, a portion of the translucent or clear member 25a may be polarised.

<FIG>) illustrates the level tracking member <NUM> at three positions in the second chamber 12b (confinement member <NUM>) P1, P2, and P3 according to an amount of fuel remaining.

<FIG>) illustrates the level tracking member <NUM> in combination with the fuel indicator <NUM> in the form of a strip of magnetochromic material. A maximum change in colour of the fuel indicator <NUM> can be observed by a user at point X.

A magnetochromic material changes its colour under the influence of a magnetic field. This change in colour usually occurs at least in the visible region of the electromagnetic spectrum. One example of a magnetochromic material is a cartridge housing the commercially available NanoBRICK (TM) MTX ink in a liquid state. NanoBRICK (TM) MTX ink uses magnetically changeable photonic crystals capable of reflecting different wavelengths of light depending on the intensity of the magnetic field that they are subjected to. When these crystals are suspended in a liquid solution, they can make the ink cartridge capable of changing colour in the presence of a magnetic field.

A magnetic viewing film may, for example, house small metal filings suspended in a coloured liquid (such as a green liquid). In the presence of a magnetic field, the filings align themselves, thus changing the hue of the film. Furthermore, magnetic viewing film comprising magnetochromic polymer microspheres provides a chromatic reaction to the presence of a proximate magnetic field.

According to embodiments, the fuel indicator <NUM> (for example, a magnetic indication system) comprises a magneto chromatic material, magneto chromatic polymer microspheres, or a magnetically active coating comprising ferro-active particles.

In embodiments, the fuel indicator <NUM> is responsible for reporting a change in the intensity of the magnetic field that is close to it, via a change in colour in the visible spectrum of the fuel indicator <NUM>. In embodiments, the fuel indicator <NUM> comprises a strip disposed along a portion of the outer body of the flame producing assembly <NUM>. In embodiments, the strip is disposed along the entire outer body of the flame producing assembly. In embodiments, the fuel indicator <NUM> is disposed on an outer portion of the sealed body <NUM> that is proximally in alignment with the predefined path of the level tracking member defined by confinement member <NUM>. In embodiments, the entire outer body of the sealed body <NUM> comprises a fuel indicator <NUM>. In embodiments, the fuel indicator <NUM> is a longitudinal strip having width of <NUM>, <NUM>, <NUM>, <NUM> or more.

According to embodiments, one or more of the level tracking member <NUM> and/or the proximal <NUM> or distal <NUM> end of the sealed body <NUM> are spaced apart d, for example using a spacing member <NUM>, along a substantially longitudinal axis L of the sealed body. The spacing member is configured to prevent the at least one magnet <NUM> of the level tracking member <NUM> becoming permanently affixed at the proximal and/or distal ends of the flame producing assembly by magnetic attraction to a metal member located at either the proximal and/or distal ends of the flame producing assembly <NUM>, respectively.

According to embodiments, the spacing member <NUM> comprises at least one resilient member, for example a spring or foam block, attached to either the proximal <NUM> or distal <NUM> end of the sealed body <NUM> and configured to support the level tracking member <NUM>.

In a typical flame producing assembly <NUM> such as a cigarette lighter as shown in <FIG>, the proximal end <NUM> of the flame producing assembly <NUM> may comprise ferromagnetic materials in the wind guard <NUM>, the ignition control portion <NUM>, and/or the fuel release assembly <NUM>, for example.

The dimensions of the spacing member <NUM> according to an example of the lighter according to the first aspect may be designed to ensure that the magnet <NUM> of the level tracking member <NUM> does not become permanently stuck to the proximal end <NUM> of the flame producing assembly <NUM> if it becomes upended between uses, for example whilst being kept in a user's pocket. The dimensions of the spacing member <NUM> are calculated to ensure that for the type of magnet <NUM> used as part of the level tracking member <NUM>, the attractive force between the magnet <NUM> and the proximal end of the flame producing assembly <NUM> are not great enough to cause the level tracking member <NUM> to become permanently stuck to the proximal end <NUM> of the flame producing assembly <NUM> either when supported in liquid fuel, or not.

In embodiments, the spacing member <NUM> may alternatively, or in addition, be included on a proximally, or distally, oriented portion of the level tracking member <NUM>. This also functions to separate the at least one magnet <NUM> from the proximal end, for example.

Provision of a spacing member <NUM> is not essential, because in some configurations, the at least one magnet <NUM> may have a small enough strength, and/or the amount of ferrous metal in the proximal and/or distal ends of the flame producing assembly may be reduced to the extent that the level tracking member <NUM> cannot become stuck at either the proximal or distal ends.

According to embodiments, the sealed body <NUM> comprises a constant circular cross section in a plane orthogonal to the longitudinal axis L. The confinement member <NUM> is a single or double spiral guide disposed on the internal surface of the sealed body <NUM>. As the amount of fuel in the sealed body <NUM> changes, the level tracking member <NUM> is rotationally displaced in the plane orthogonal to the longitudinal axis L as the level tracking member <NUM> moves in the direction of the longitudinal axis <NUM>, thus enabling the fuel indicator <NUM> to change according to an angular component around the sealed body <NUM>.

According to embodiments, the inner wall of the second chamber 12b and the level tracking member <NUM> both have complementary non-circular cross sections in a plane orthogonal to the longitudinal axis L, thus preventing rotational movement of the level tracking member <NUM> in a plane orthogonal to the longitudinal axis L.

<FIG> schematically illustrates a method <NUM> of using a flame producing assembly according to aspects discussed herein.

According to a second aspect of the invention, there is provided a method <NUM> for using a flame producing assembly, comprising:.

For example, in use, a user sets the flame producing assembly <NUM> on a substantially flat surface, or aligns it such that its centre perpendicular (longitudinal) axis L is in substantially the same direction as vertical. The level tracking member <NUM> moves and comes to rest at the same level as the remaining fuel supply <NUM>. The magnitude of the magnetic field strength close to the magnet <NUM> is greatest, thus causing a change of colour of a magnetically active indicator pigment or fluid adjacent to the magnet in, or on, the fuel indicator.

The user is able to read the change of colour corresponding to the amount of liquid fuel remaining. For example, the fuel indicator may change to a darker green colour, or the magnetochromic material changes colour. For example, NanoBRICK (TM) ink may change from a brown to a blue hue. In examples, a legend or scale adjacent to the fuel indicator may provide numerical feedback concerning the amount of remaining fuel.

In the preceding specification, numerous specific details are set forth in order to provide a thorough understanding. It will be apparent, however, to one having ordinary skill in the art that the specific detail need not be employed to practice the present disclosure. In other instances, well-known materials or methods have not been described in detail in order to avoid obscuring the present disclosure.

Claim 1:
A flame producing assembly (<NUM>), comprising:
- a sealed body (<NUM>) comprising a proximal (<NUM>) and a distal (<NUM>) end aligned on a longitudinal axis (L), wherein the sealed body comprises a void and a visible portion;
- a fuel supply (<NUM>) comprising liquid fuel accommodated in the void within the sealed body;
- a fuel release assembly (<NUM>) enabling a controllable release of the fuel supply (<NUM>) in gaseous form from the sealed body (<NUM>);
- a fuel indicator (<NUM>) configured to indicate a remaining amount of liquid fuel contained in the sealed body (<NUM>) to a user of the flame producing assembly (<NUM>), characterized in that at least a portion of the fuel indicator (<NUM>) is capable of changing appearance of the visible portion of the sealed body (<NUM>) when in proximity to a magnetic field; wherein a level tracking member (<NUM>) comprises at least one magnet (<NUM>) supported by a buoyant member (<NUM>) and
wherein the at least one magnet (<NUM>) is configured to apply a magnetic field to the fuel indicator (<NUM>), thereby causing the fuel indicator (<NUM>) to indicate an amount of liquid fuel remaining in the sealed body (<NUM>) to a user.