[Type of Document] Patent Specification

[Title of the Invention] LIQUID-FUEL COMBUSTION APPLIANCE Inventor: Toshihiro Ichikawa

[Field of the Invention]

[0001]

The present invention relates to a liquid-fuel combustion appliance, in particular to a construction around a combustion wick of a liquid-fuel combustion appliance, wherein the aforementioned combustion wick is used for burning liquid fuel delivered to the upper part of the wick by capillary action.

[Background of the Invention] [0002]

Normally, fuel combustion appliances used for lighting such devices as smoking tools, ignition units, torches, illumination devices, etc., operate with various fuels such as ethyl alcohol, or similar alcohol-type fuels, benzene-type fuels including gasoline, gaseous butane, propane, or similar liquefied gaseous fuels, etc., and depending on the type of fuel used by the appliances, they can differ in construction, performance characteristics, and convenience for the user. For example, known in the art are liquid- fuel combustion appliances operating on alcohol or a similar fuel, wherein the liquid fuel is delivered from a fuel tank to a combustion portion of the appliance by using a combustion wick having a combustion portion on the tip of the wick to which the liquid fuel is sucked using surface tension of the liquid fuel and capillary action to deliver the fuel through continuous microscopic perforations, or microscopic gaps, between the fibers combined into a bundle.

[0003]

It is also known that in order to protect the liquid- fuel combustion appliances against evaporation of the liquid fuel from the appliance, the latter is normally provided with a closure cap used for closing or opening the end of the combustion wick, i.e., the combustion portion of the wick. In order to prevent leakage of the liquid fuel from the

fuel tank through the wick or in order to prevent impairment of ignition because of suction of atmospheric air into the fuel tank under effect of a pressure difference between the inner pressure of the tank and the external pressure, it was proposed to reduce the aforementioned pressure difference by providing a through-channel for connecting the interior of the fuel tank with the surrounding atmosphere [see Patent Reference I].

[Patent Reference 1] Japanese Unexamined Patent Application H 10-227457

[Disclosure of the Invention] [Problems to be Solved by the Invention] [0004]

However, the liquid-fuel combustion appliance disclosed in Patent Reference 1 has a closed space between the ignition portion and the closure cap, and the opening of the through channel that connects the fuel tank with the atmosphere is either connected to the aforementioned closed space when the closure cap is closed, or is closed during closing of the closure cap. Therefore, if the closure cap is closed after long-time burning of the fuel evaporated from the surface of the combustion portion of the wick, the aforementioned through channel is closed while the combustion portion is in a hot state. Therefore, instant extinguishing of the burning causes a sharp drop in temperature with the resulting decrease of pressure in the aforementioned closed space. This, in turn, induces a pressure difference between the interior of the fuel tank and the external pressure, and the fuel is raised to the combustion portion of the wick.

[0005]

Since the fuel rises from the fuel tank, in some instances the fuel may fill the aforementioned closed space, and when the closure cap is opened for the next ignition, the accumulated fuel is spread to the surrounding area, and ignition may cause a flame of increased size. A small amount of fuel may penetrate into the aforementioned closed space even without combustion, e.g., when a user manually shakes the liquid-fuel combustion appliance.

[0006]

Based on the above information, it is an object of the present invention to provide a liquid-fuel combustion appliance without a space between the combustion portion of the wick and the inner walls of the closure cap and with the formation of a stable flame.

[Means for the Solution of the Problem] [0007]

A liquid- fuel combustion appliance of the present invention comprises: an appliance body having a fuel tank that contains liquid fuel; a combustion wick for sucking up a liquid fuel contained in the aforementioned fuel tank by capillary action and burning the fuel at its combustion part at the tip of the wick; an ignition unit for delivering sparks to the combustion portion; a closure cap for closing or opening the upper part of the appliance body; and a through channel that connects the interior of the fuel tank with the atmosphere; the aforementioned appliance being characterized by further comprising a tubular sleeve member that is arranged around the outer periphery of the combustion wick and supports the combustion wick; the closure cap having a closing member that closes or opens the combustion portion, the aforementioned closing member having a first seal that comes into contact with the tip of the sleeve member and closes the combustion portion and a through-channel seal that closes the through passage.

[0008]

The liquid- fuel combustion appliance of the invention may be further provided with a second seal, which is installed in the appliance body and comes into contact with the through-channel seal, the aforementioned second seal being arranged around the sleeve member and having an outer sealing element that is maintained in contact with the aforementioned closing member.

[0009]

The liquid- fuel combustion appliance of the present invention may have the first seal and the second seal made from rubber materials of different hardness.

[0010]

The liquid- fuel combustion appliance of the present invention may have the combustion portion of the combustion wick projecting from the tip of the aforementioned sleeve member when the closure cap is open and inserted deeper into the sleeve member when the closure cap closed.

[0011]

The liquid- fuel combustion appliance of the present invention may have the combustion wick urged by a spring in the direction of the aforementioned projection.

[0012]

The liquid- fuel combustion appliance of the present invention may have a spherical surface on the side of the first seal that faces the combustion portion.

[Effects of the Invention] [0013]

The liquid- fuel combustion appliance of the present invention is provided with a tubular sleeve that surrounds the combustion wick, and the closure cap is provided with a closing member, which has a first seal capable of coming into contact with the sleeve member and closing the combustion portion of the wick. The closure cap is further provided with a through-channel seal that closes the through passage, and the first seal and the sleeve member close the aforementioned combustion portion. The above construction makes it possible to eliminate a closed space around the combustion portion. Even though the through channel is closed when the combustion portion is in a hot state, a reduced pressure-decrease space makes it possible to reduce amount of the fuel sucked to the upper end of the wick, and even if a small amount of the liquid fuel is raised to the combustion portion, migration of fuel from the fuel tank can be prevented since the space for penetration of fuel is absent. Since there is no space for accumulation of fuel, with the closure cap in a closed state, the fuel will not be spread around even if the liquid- fuel combustion appliance is shaken by the user's hand. Therefore, when the closure cap is

opened for the next ignition of the flame, no fuel is spread around, and this provides stability of the flame.

[0014]

Since the liquid-fuel combustion appliance is provided with a second seal, which is inserted into the appliance and is in contact with the through channel, and since the second seal is arranged around the sleeve member and has an outer sealing element that is maintained in contact with the closing member, it becomes possible to close the through channel and the combustion portion simultaneously. This feature prevents evaporation of liquid fuel through the channel and from the combustion wick.

[0015]

Since the first seal and the second seal are made from rubber materials of different hardness, when the through-channel seal comes into contact with the first seal and the second seal simultaneously, the difference in contact areas provides different contact pressures on respective seals, and if the difference in hardness is selected so that the seal with the higher contact pressure has a higher hardness, it will be possible to ensure reliable sealing on the contact surface without weakening of the sealing force on any of the seals.

[0016]

Furthermore, when the closure cap is opened, the combustion portion of the combustion wick projects from the end of the sleeve member, and when the closure cap is closed, the combustion portion of the wick is shifted deeper into the sleeve member. When compared with a conventional device, in which the combustion portion of the wick does not project from the sleeve member which is made, e.g., from metal, and the heat is transferred to the metal part, and the size of the flame is reduced, in the construction of the invention the combustion portion of the wick projects from the end of the metal sleeve. This increases the evaporation area of the liquid fuel and results in an improved ignition and greater size of the flame.

[0017]

Since the surface of the first seal on the side facing the combustion portion is spherical, it becomes possible to reduce the load that is applied to the tip of the combustion portion when the latter comes into contact with the first seal during closing of the closure cap.

[Description of the Preferred Embodiment] [0018]

A lighter 1 made in accordance with one embodiment of a liquid-fuel combustion appliance of the present invention will now be described in detail with reference to the attached drawings. Fig. 1 is a partially disassembled central view of the lighter 1. Fig. 2 is a three-dimensional view of an essential part of the closing cap 5 in the direction of arrow A in Fig. 1. Fig. 3 is a three-dimensional view of an essential part of the lighter 1 in the direction of arrow B in Fig. 1. For convenience of further description, the view of the lighter 1 from the flame side (the image in the upper part of Fig. 1) will be referred to as the top view; views of the lighter from the left and right sides of the image shown in Fig. 1 will be referred to as left and right views, respectively; a view of the lighter in Fig. 1 from the rear side of the image shown in Fig. 1 will be referred to as the rear view; and the view of the lighter from the front side of the image shown in Fig. 1 will be referred to as the front view.

[0019]

As shown in Fig. 1, the lighter 1 of the illustrated embodiment of the invention (i.e., a liquid-fuel combustion appliance) consists of the following main parts: a lighter body 2 (appliance body) with a fuel tank 21 that contains liquid fuel; a combustion wick 3 for burning the liquid fuel sucked from the fuel tank 21 at the combustion part 31 at the tip of the wick; an ignition unit 4 that ignites the combustion part 31 of the wick; and a closure cap 5 for tightly closing the upper end of the lighter body 2.

[0020]

The lighter body 2 is made from a synthetic resin, its lower end is closed by a cover 2a, and its interior accommodates a fuel tank 21 for storing liquid fuel. On the left front and rear sides, the lighter body has lugs 2b for supporting the closure cap 5 by means of hinges on pins inserted into openings 2c formed in the lugs 2b. On the right upper side, the lighter body 2 has a cutout 2d for accommodation of a one-touch member 6 which will be described later.

[0021]

The upper wall 22 of the fuel tank 21, which is located at the upper part of the lighter body 2, is made integrally therewith. If necessary, however, the upper wall 22 of the tank can be made in the form of a separate cover. The fuel tank 21 is filled with a liquid- absorptive cotton 21a made from liquid-absorptive fibers (e.g., PP fibers). The liquid- absorptive cotton 21a may be impregnated with a liquid fuel comprising, e.g., a mixture of 50 wt.% of isopropyl alcohol, 40 wt.% of heptane, and 10 wt.% of terpene oil. Furthermore, the lighter body 2 has an opening 22a formed in its upper surface at a predetermined distance to the left of the center for insertion of a sleeve member 32, which is described below. The body also has an opening 22b formed in the bottom of the opening 22a for insertion of the combustion wick 3. The sleeve member 32 is a tubular body made from a crystalline polymer. The upper end of the sleeve member 32 projects from the opening 22a, and the interior wall of the sleeve holds the combustion wick 3. From the viewpoint of special disposal, which is described below, it is recommended to produce the sleeve member 32 from a crystalline polymer such as a thermoplastic resin or thermosetting resin, but, if necessary, the sleeve can be made from a metal in the form of a zinc die cast, brass, or the like.

[0022]

The combustion wick 3 is made from polyester fibers in the form of a rod with a [semi]- spherical upper end. Approximately in the middle of its upper part in the vertical direction, the combustion wick 3 has a stepped portion 3 a from which the wick gradually tapers with a decrease in diameter in the downward direction. The combustion wick 3 is held in the sleeve member 32 by interaction of the inner walls of the sleeve with the part

of the wick above the stepped portion 3 a. When the closure cap 5 is open, the combustion portion 31 is urged upward by a spring 33 made from resin which is inserted into a gap between the bottom of the opening 22a and the lower end face of the stepped portion 3 a so that the wick slides up in the vertical direction inside the sleeve member 32 to a position in which the upper end of the combustion portion 31 protrudes from the upper end of the sleeve member. It is recommended that the spring 33 be made from a resin material suitable for a special method of discarding, which will be described below. In order to decrease cost, however, the spring can be made from metal. The lower end of the combustion wick 3 that passes through the opening 22b protrudes into the fuel tank 21 in a substantially vertical direction and is in contact with the liquid-absorptive cotton 21a for absorbing the liquid fuel and for igniting and burning the liquid fuel at the protruding tip (combustion portion 31) of the wick when a spark is generated.

[0023]

A through passage 22c that connects the interior of the fuel tank with the atmosphere and that passes to the fuel tank is formed in the tank upper wall in a position to the left of the sleeve member 32. To the right of center, the tank upper wall 22 has a stepped portion 22d that extends downward. Through an intermediate casing 23, the stepped portion 22d accommodates an ignition unit 4 which will be described later.

[0024]

The intermediate casing 23 has a tubular receiving section 23 a that is open from both ends and is intended for insertion of an ignition unit 4 described below, an engagement element 23b that extends to the left from the upper edge of the tubular receiving section 23 and downward for engagement with the tank upper wall 22, and an opening 23c located close to the receiving section 23 a and to its right for passing a detent 6a of the one-touch member 6 described below. On its outer periphery, the tubular receiving section 23a has a contact step portion 23d for engagement with another detent 6b of the one-touch member 6. Furthermore, substantially rectangular wall portions 23e (Fig. 1) that extend up from the tubular receiving section 23 a are formed on the front and rear sides of the intermediate casing 23.

[0025]

The one-touch member 6 is made from a synthetic resin. Its lower wall 6c is fixed to the bottom part 23 f that extends to the right and down from the tubular receiving section 23 a of the intermediate casing 23. The aforementioned detent 6a extends up from the right side, and the detent 6b extends up from the left side of the lower wall 6. The detent 6a passes up and through the aforementioned opening 23 c, and its upper end has a flexible portion with a latch 6d for engagement with the closure cap 5. The one-touch member is located in the aforementioned cutout 2d of the lighter body 2 so that the flexible-portion side of the detent 6a projects to the outside of the lighter body 2, and when the flexible portion is pushed inward, the latch 6d is disengaged from the closure cap 5. The second detent 6b is directed up and with an inclination to the left, and its tip engages the aforementioned contact step portion 23 d. Thus, the parts that constitute the lighter body 2, as a whole, are made essentially from resin.

[0026]

The ignition unit 4 is inserted into the receiving section 23 a of the intermediate casing 23. The ignition unit 4 comprises an ignition stone 42 inserted into a tubular metal spacer 41 and a stone-pushing spring 43 combined into a unit.

[0027]

The spacer 41 has on its outer periphery an annular shoulder 41a formed in its upper part above the middle of the length. The portion of the spacer 41a below the annular shoulder 41a is inserted into a through opening of a bracket 44, which is made from a metal plate. The bracket 44 consists of a flat portion 44a that contains an opening for passing the spacer 41, a vertical portion 44b bent up from the left side of the flat portion 44a, and a windshield 44c arranged around the combustion wick 3. The lower side of the flat portion 44a is in contact with the upper side of the metal-plate support bracket 45.

[0028]

The support bracket 45 consists of a flat support plate 45 a, which has an opening for passing the spacer 41. The lower side of the support plate 45 a is fixed to the upper surface of the intermediate case 23. The support bracket also has posts 45b on the front and rear sides between which the flat support plate is squeezed and which have openings (not shown) for rotatingly supporting a rotary axis 48, which is described below. A spark wheel 46 has a ring-shaped configuration and is fixed to a pair of side wheels 47, which are located on the front and rear sides thereof and which are rotated for sparking. Both side wheels are attached to a rotary shaft 48 that passes through the centers of the wheels and rotate together with the wheels. The ignition stone 42 is located under the spark wheel 46 and is urged upward to contact the spark wheel 46 by means of the spring 43.

[0029]

Thus, in the ignition unit 4 assembled from the parts described above, rotation of the side wheels causes rotation of the spark wheel 46, and since the file-like surface of the spark wheel 46 is maintained in contact with the upper end of the ignition stone 42, which is urged thereto by the spring 43, the aforementioned interaction causes sparking, and the sparks fly out in the direction of the combustion portion 31. The above-described parts of the ignition unit 4 are made mainly from metal.

[0030]

The following description relates to the closure cap 5. In this description, the lighter will be considered in the position, in which the lighter body 2 is located below [the closure cap 5] and the closure cap 5 is located on the left side of the lighter body 2. The closure cap 5 is made from metal and has a substantially box-like shape with an opening 5 a that faces down when the cap is closed. The left lower end of the closure cap 5 is pivotally supported on pins 51 which are inserted into the openings 2c of the lighter body 2. Normally, the closure cap 5 is urged in the direction of opening by a twist spring 52 that fits onto the aforementioned pins 51. On the inner side of its lower right end, the closure cap 5 has a tooth 5b that projects toward the interior of the cap. By engaging the latch 6d of the one-touch member 6, the tooth 5b holds the closure cap 5 in the closed position. On the upper side of its inner wall, the closure cap 5 has a downwardly directed annular

projection 5c. This projection serves for attaching an inner cap 53 to the upper side of the inner surface of the cap.

[0031]

The inner cap 53 is made from metal and consists of a plate portion 53a that extends along the inner surface of the upper side of the closure cap 5 and a tubular projection 53c (Fig. 2) that projects inward into the opening 5a from the plate portion 53a and has on its lower end a cylindrical closing member 53b for closing or opening the combustion portion 31 of the wick. The upper end of the tubular projection 53c has a circular recess 53d which fits onto the aforementioned annular projection 5c.

[0032]

A specific feature of the present invention is that the closing member 53b has a first seal 54 that can be brought in contact with the tip of the sleeve member 32 and can tightly close the combustion portion 31 and a through-passage seal 55 that closes the through passage 22c (Fig. 2). The first seal 54 comprises a substantially cylindrical body made from resin, which is inserted into the opening of the closing member 53b. The lower surface 54a of the first seal 54 comprises a concave spherical surface (that faces the combustion portion 31). The through-passage seal 55 comprises a cylindrical body formed integrally with the tubular projection 53c as part of its outer peripheral wall. The seal 55 has a larger diameter than the through opening 22c, and when the closure cap 5 is closed, the seal 55 closes and seals the through opening 22c.

[0033]

The tank upper wall 22 of the lighter body 2 has a second seal 24, which comes into contact with the aforementioned through-passage seal 55 when the closure cap 5 is closed. As shown in Fig. 3, the second seal 24, which is made from rubber and comprises a cylindrical body that has a diameter substantially equal to the diameter of the through- passage seal 55, has a sealing element 24a with a through central opening substantially of the same diameter as the diameter of the through channel 22c and an outer sealing element 24b that includes a part of the sealing element 24a and surrounds the periphery

of the sleeve member 32. The aforementioned through opening of the second sealing element communicates with the through channel 22c that passes through the rubber insert 22e formed in the upper wall 22 of the tank (Fig. 1).

[0034]

The first seal 54 and the second seal 24 are made from rubber materials of different hardness. For example, the first seal 54 has hardness equal to 55 units, while the second seal has hardness equal to 70 units. The seals can be made, e.g., from NBR (nitrile butadiene rubber). Such choice of materials is based on the fact that when the first seal 54 and the sleeve member 32 together with the second seal member 24 and the through- passage seal 55 come into contact simultaneously, the respective rubber parts, which have different contact areas, experience different contact pressures; therefore, by providing the parts with different degrees of hardness as in the above combination, it is possible to ensure a reliable seal without weakening the sealing force acting in any direction.

[0035]

Fig. 4(a) is a central longitudinal sectional view of the closure cap 5 in an open state.

Fig. 4b is a central longitudinal sectional view of the closure cap 5 during the closing operation. Fig. 4c is a central longitudinal sectional view of the closure cap 5 in a closed state.

[0036]

When the closure cap 5 is in the open state shown in Fig. 4(a), the combustion portion 31 formed on the end of the combustion wick 3 projects from the tip of the sleeve member 32. When in this state, the sparks generated by the ignition unit 4 are directed onto the combustion portion 31 , the sparks ignite the liquid fuel that evaporates from the surface of the combustion portion 31, the fuel starts a fire, and a flame of a predetermined length occurs. Since the liquid fuel is constantly sucked by the lower end of the combustion wick 3 [from the content of the tank] and moves up, the evaporated fuel continuously burns and maintains a steady flame, and the lighter can be used for its purpose. When use of the lighter is completed, the closure cap 5 is pushed down. When this happens, as

shown in Fig. 4(b), the element with the spherical surface 54a of the first seal 54 inserted into the closing member 53b comes into contact with the combustion portion 31 on the end of the combustion wick 3. The provision of the aforementioned spherical surface 54a in the first seal 54 makes it possible to reduce the load that acts on the tip of the combustion portion when the first seal contacts the combustion portion 31 during the closing operation.

[0037]

As shown in Fig. 4(c), when the closure cap 5 is pushed down further, the spherical surface 54a applies pressure to the tip of the combustion portion 31, the spring 33 is compressed, and the combustion wick 3 is shifted down, e.g., H = 4 mm, and is inserted deeper into the sleeve member 32. Further, the spherical surface 54a comes into contact with the tip of the sleeve member 32, the combustion portion 31 of the wick is closed and sealed, the through-passage seal 55 comes into contact with the sealing element 24a of the second seal 24, and the through channel 22c is closed and sealed.

[0038]

Thus, as has been described above, since the combustion portion 31 is closed and sealed by the first seal 54 and the sleeve member 32, it becomes possible to eliminate closed spaces around the periphery of the combustion portion; and even though the through channel 22c is closed with the combustion portion 31 in a hot state because the pressure reducing space is narrow, it becomes possible to diminish suction and to raise the fuel. Also, if the liquid fuel is sucked to the combustion portion 31 and is raised because the space for entering the fuel is very small, migration of the fuel from the fuel tank 21 is prevented. The fuel will not migrate from the fuel tank even if the lighter 1 with the closed cap 5 is shaken by hand since there is no space where the liquid fuel can penetrate. Therefore, when the closure cap 5 is opened for the next ignition of the flame, the flame will ignite in a safe manner because the fuel did not spread into the surrounding area.

[0039]

Furthermore, since the lower end of the tubular projection 53c contacts the outer sealing element 24b and the ignition portion 31 closes by the aforementioned first seal 54, the peripheries of the parts of the wick 3 and the sleeve 32 that project from the tank upper wall 22 are closed. Since the through channel 22c and the combustion portion 31 are closed simultaneously, evaporation of the liquid fuel through the channel 22 and from the combustion wick 3 is prevented.

[0040]

At the same time, engagement occurs between the tooth 5b of the closure cap 5 and the latch 6d of the one-touch member 6, whereby the closure cap 5 is secured to the upper edge of the lighter body 5, and the flame is extinguished. The flame may also be extinguished by the user's blow.

[0041]

When the lighter 1 is used, the one-touch member 6 is pushed into the lighter body 6, and the tooth 5b is disengaged from the latch 6d. At the next moment, the closure cap opens to the position shown in Fig. 4(b) under the effect of the resilient force of the twist spring 52. Under the effect of the force developed by the spring 33, the combustion portion 31 of the combustion wick 3, which is inserted into the sleeve member [THIS WORD HAS A TYPO IN THE JAPANESE ORIGINAL - TR. NOTE] 32 to the position shown in Fig. 4(c) will project from the tip of the sleeve by H = 4 mm to the position shown in Figs. 4(a) and (b). Sparks delivered in this condition from the ignition unit 4 to the combustion portion 31 will ignite the liquid fuel evaporated from the surface of the combustion unit 31 and will form a flame. The lighter 1 is now ready for use.

[0042]

In a conventional lighter, which has a sleeve 32 made, e.g., from metal but without a projecting portion, the combustion portion 31 is located inside the sleeve member 32. Therefore, the heat is consumed by the metal part, and the flame is small. In the device of the invention, however, the tip of the combustion portion 31 projects from the sleeve

member 32. This increases the fuel evaporation surface, improves flame formation conditions, and increases the size of the flame.

[0043]

As shown in Fig. 1, the lighter 1 has a construction in which the closure cap 5 can be disconnected from the lighter body by bending the ends of the pins 51 and removing them from the openings 2c of the lighter body. Furthermore, the ignition unit 4 may be extracted from the tubular receiving section 23 a by shifting the detent 6b of the one-touch member 6 away from the lighter body 2 for disconnecting detent 6b from the contact step portion 23 d and then pulling up the ignition unit 4 for extraction from the tubular receiving section 23 a.

[0044]

As has been described above, the closure cap 5 and the ignition unit 4 are the only components of the lighter that are made from metal, while approximately 95% of the remaining parts of the lighter, including the lighter body, are made from resin. Therefore, the metal parts can be separated from those made of plastic when the lighter is discarded.

[Brief Description of Drawings]

[0045]

Fig. 1 is a central longitudinal sectional view of the lighter [of the invention].

Fig. 2 is three-dimensional view of an essential part of the closing cap 5 in the direction of arrow A in Fig. 1.

Fig. 3 is a three-dimensional view of an essential part of the lighter 1 in the direction of arrow B in Fig. 1.

Fig. 4 shows several central sectional views of the lighter illustrating the closure cap in an open state, during closing, and in a closed state.

[Reference Numerals Used in the Description and Drawings] [0046]

1 lighter (liquid-fuel combustion appliance)

2 lighter body (appliance body)

21 fuel tank

22 tank upper wall 22c through channel

3 combustion wick

31 combustion portion

32 sleeve member

33 spring

4 ignition unit

5 closure cap 53b closing member

54 first seal

54a part with spherical surface

55 through-passage seal 24 second seal

24a sealing element

24b outer sealing element