Abstract:
The present discussion generally describes a liquid fuel burning device such as an oil lamp having a reservoir for holding the liquid fuel and a flange substantially covering the liquid fuel holding area of the reservoir. The flange is sized and located to provide an opening between a perimeter of the flange and an inner surface of the reservoir. The opening permits a level of the liquid fuel to be monitored and/or checked during filling of the reservoir. Thus, the chance of having an overflow of liquid fuel or an under-filled reservoir is substantially reduced. The flange is configured with a downward slope to allow liquid fuel to drain toward the opening, if liquid fuel gets on the flange during filling of the device.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Technical Field  
         [0002]     This disclosure is generally related to a lamp device that burns a combustible substance by drawing the substance up through a wick, for example an oil lamp.  
         [0003]     2. Description of the Related Art  
         [0004]     Candles, gel pots, and oil lamps are commonly used as decorative light sources and can also be used to disperse fragrances. These light sources typically produce a yellow flame by burning a combustible substance (e.g., wax, gel, oil, etc.), which is continuously drawn up through a wick by capillary action. In the case when a wax or gel is used as the combustible substance, the heat of flame melts a small pool of the wax in the vicinity of the wick stem to allow the melted wax to be drawn up through the wick.  
         [0005]     Unlike candles or gel pots, the oil in an oil lamp is already in a liquid state and does not need to be heated by the flame to invoke capillary action. The liquid form of the oil, however, makes an oil lamp more susceptible to spillage of the oil either during use or during refilling of the oil. Typically, the oil is held in a container and the only access to the oil is through the wick. A cover over the oil acts as barrier to prevent the flame from igniting the oil held in the container. The cover can be removable from or integral with the container.  
         [0006]     When the cover and container are integral, the process of filling or refilling an opaque (i.e., non-glass or non-transparent) oil lamp requires at least that the flame be temporarily extinguished and the wick removed. The wick is removed and oil is added into the container through the wick aperture, which often requires the use of a small or specialized funnel which is often misplaced or lost. Where the cover is removable, the flame must still be extinguished before refilling to prevent the oil in the container from igniting.  
         [0007]     A common purpose of oil lamps is to disperse fragrance molecules into the air. However, when the lamp is covered or when the container and cover are integral, the dispersal of fragrance molecules into the air is significantly restricted, if not nonexistent. Some devices propose to disperse the fragrance molecules through the wick. But, the fragrance molecules are usually destroyed or significantly altered when the oil is drawn up through the wick and burned by the flame. The combustion process tends to produce a “fuel” or “burnt” smell instead of the desired odor of the fragrance.  
         [0008]     One approach to an oil lamp that emits a fragrance when ignited is disclosed in U.S. Pat. No. 6,555,069, issued to Ferguson, in which the oil lamp includes a ceramic diffuser. The ceramic diffuser of the &#39;069 patent functions as a secure top, absorbs some of the oil, and releases the absorbed oil into the surrounding air. A drawback is that this type of oil lamp still requires that the flame be extinguished and the top removed before more oil can be added to the container.  
         [0009]     Consequently, there remains a need to maintain the oil securely in the oil lamp, allow a sufficient number of fragrance molecules to be dispersed into the air while the oil lamp is burning, protect the oil from the open flame, and provide a means to easily fill and refill the oil lamp with a reduced risk of underfill, overflow, or leakage. Further, the filling and refilling of the oil lamp should be easy and quick without the need for specialized funnels or tubes to get the oil into the container.  
       SUMMARY OF THE INVENTION  
       [0010]     In one aspect of the invention, a liquid-fueled lamp includes a reservoir to hold liquid fuel, the reservoir having an outer surface and an inner surface; a wick holder supported within the reservoir; a flange coupled with the wick holder, the flange configured with a downward slope directed from the wick holder toward the inner surface of the reservoir; and an opening located between a perimeter of the flange and the inner surface of the reservoir, the opening sized to provide a visual indication of a fuel level of the liquid fuel in the reservoir.  
         [0011]     In another aspect of the invention, a lamp includes a reservoir comprising a wall having an interior surface and an exterior surface, the interior surface forming a reservoir for receiving a liquid fuel, the reservoir open at one end thereof and closed at an opposite end; a wick holder received in the reservoir and coupled to the reservoir, the wick holder forming at least one passage for supportably receiving a wick; a flange extending from the wick holder toward the interior surface, the flange having a perimeter, the perimeter being spaced from the interior surface to form a gap therebetween. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]     In the drawings, identical reference numbers identify similar elements or acts. The sizes and relative positions of elements in the drawings are not necessarily drawn to scale. For example, the shapes of various elements and angles are not drawn to scale, and some of these elements are arbitrarily enlarged and positioned to improve drawing legibility. Further, the particular shapes of the elements as drawn, are not intended to convey any information regarding the actual shape of the particular elements, and have been solely selected for ease of recognition in the drawings.  
         [0013]      FIG. 1  is a front, left isometric view of a lamp for receiving, holding, and burning liquid fuel such as oil according to one illustrated embodiment.  
         [0014]      FIG. 2A  is a cross sectional view of the device of  FIG. 1  with a wick holder coupled to a reservoir according to one illustrated embodiment.  
         [0015]      FIG. 2B  is a cross sectional view of a wick holder mechanically coupled to a reservoir according to another illustrated embodiment.  
         [0016]      FIG. 2C  is a cross sectional view of a lamp having a truncated wick holder according to another illustrated embodiment.  
         [0017]      FIG. 3  is front, right isometric view of a wick holder according to one illustrated embodiment. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0018]     In the following description, certain specific details are set forth in order to provide a thorough understanding of various embodiments of the invention. However, one skilled in the art will understand that the invention may be practiced without these details. In other instances, well-known structures associated with lamps (e.g., oil lamps), lanterns, camping stoves, wicks, and other similar devices may not be shown or described in detail to avoid unnecessarily obscuring descriptions of the embodiments of the invention.  
         [0019]     Unless the context requires otherwise, throughout the specification and claims which follow, the word “comprise” and variations thereof, such as, “comprises” and “comprising” are to be construed in an open, inclusive sense, that is as “including, but not limited to.” 
         [0020]     The headings provided herein are for convenience only and do not interpret the scope or meaning of the claimed invention.  
         [0021]      FIG. 1  shows an oil lamp  10  having a reservoir  12  and a lid  14  according to one illustrated embodiment. The reservoir  12  is bowl shaped with an inner surface  12   a  and an outer surface  12   b . The inner surface  12   a  forms a reservoir to receive fuel, for example a liquid fuel such as oil (with or without fragrance), citronella (lemon odor), citronellol (rose-like odor), or any other like fuel that is slow burning and permissible in a liquid-fueled lamp. The reservoir  12  has a rim  12   c  that forms an opening to at an upper end thereof to receive liquid fuel. A flange  16  and a wick holder  18  are positioned within the reservoir  12 . The reservoir  12  can be made out of metal (e.g., stainless steel, aluminum, bronze, copper, etc.), ceramic, or some other flame resistant, opaque material. The lid  14  and the flange  16  can be made out of the same or an equivalent material. In the illustrated embodiment, the reservoir  12 , lid  14 , and flange  16  are made out of stainless steel and the wick holder  18  is made from bronze. It is appreciated and understood that the reservoir  12 , the lid  14 , flange  16 , and wick holder  18  can vary in size and shape and the illustrated configuration is exemplary.  
         [0022]     The lid  14  may include a decorative handle  14   a  to allow for easy removal and replacement of the lid  14 . When the oil lamp  10  is lit, the lid  14  can be used to cover the reservoir  12  and wick holder  18  to substantially starve the flame for oxygen and ultimately extinguish the flame. In addition, leaving the lid  14  on when the oil lamp  10  is not in operation helps keep the oil from evaporating.  
         [0023]      FIG. 2A  shows the reservoir  12  of the oil lamp  10  with oil  20  that is filled to an oil level  20   a . In the illustrated embodiment, the reservoir  12  is approximately semi-hemispherical and configured with a substantially flat bottom surface  22 , which permits the oil lamp  10  to be placed in a stable configuration on a flat surface such as a coffee table, counter top, or shelf, for example. Alternatively, the oil lamp  10  may be supported by a holder such as a wrought iron base, for example.  
         [0024]     The wick holder  18  is supported on the inner surface  12   a  of the reservoir  12 . Although the wick holder  18  can simply rest on the inner surface  12   a , such would not be as desirable as a wick holder  18  that is held stationary in the reservoir  12 . In the illustrated embodiment, the wick holder  18  is mechanically coupled with the reservoir  12  to keep the wick holder  18  at least temporarily fixed. There are a variety ways to fixedly or removably mechanical couple the wick holder  18  to the reservoir  12 , for example by complementary threads, complementary clipping elements, etc.  
         [0025]     The wick holder  18  includes a first protuberance  24  that complementarily recesses into a clip  26  extending from the reservoir  12 . The wick holder  18  can be snapped or twisted into place. In an alternate embodiment shown in  FIG. 2B , the wick holder  18  and an inner ring  28  are configured with complementary, helical threads that permits the wick holder  18  to selectively be rotationally engaged and disengaged from the reservoir  12 .  
         [0026]     Referring back to  FIG. 2A , the wick holder  18  further includes a second protuberance  30 . The second protuberance  30  supports the flange  16 . The flange  16  is provided with an opening  16   a  sized to fit around the perimeter of the wick holder  18  while not sliding down over the second protuberance  30 .  
         [0027]     In  FIGS. 2A and 2C , the flange  16  has a first height “A” and a second height “B,” both relative to the bottom surface  22  of the reservoir  12 . The first height “A” is greater than the second height “B,” which means that the flange  16  is configured to slope downward from its support location on the wick holder  18  toward the inner surface  12   a  of the reservoir  12 . As shown in the illustrated embodiment, the flange  16  may even have a slight, concave curvature. The downward slope, with or without the curvature, encourages oil that is spilled onto or otherwise contacts the flange  16  to run off the flange and into the reservoir  12 .  
         [0028]     The flange  16  further includes an outer perimeter  16   b  sized to fit within the reservoir  12 . In one embodiment, a cross-sectional area of the reservoir  12 , taken parallel to the horizontal, may continually increase as one follows the contour of the inner surface  12   a  of the reservoir  12  upward. One skilled in the art will appreciate and understand that cross-sectional area of the reservoir  12  increases exponentially as a function of the diameter (d) of the inner surface  12   a  (area=π*d 2 /4). The outer perimeter  16   b  of the flange  16  is sized to form an opening or gap  32  with respect to the inner surface  12   a  of the reservoir  12 . Thus, the flange  16  will have a smaller radius and outer perimeter  16   b  where the flange  16  is situated at a low elevation in the reservoir  12 , while the flange  16  will have a larger radius and outer perimeter  16   b  where the flange  16  is situated at a high elevation in the reservoir  12 . In any case, the outer perimeter  16   b  of the flange  16  is smaller than the perimeter of the inner surface  12   a  of the reservoir  12  at a location on the inner surface  12   a  opposed to the outer perimeter  16   b . The gap  32  is large enough to receive the oil  20  during the filling or refilling process without causing the oil  20  to substantially back-up when the oil  20  is poured into the reservoir  12  at reasonable rate. In one embodiment, the oil  20  is poured directly onto the flange  16 , but away from the wick holder  18 , where the oil  20  then runs down the flange  16 , through the gap  32 , and into the reservoir  12 .  
         [0029]      FIG. 2C  illustrates an alternate embodiment in which an upper edge  18   a  of the wick holder  18  is flush with an inner portion  16   c  of the flange  16 . In other words, the wick holder  18  is truncated to be flush with the inner portion  16   c  of the flange  16 .  
         [0030]     One advantage of the gap  32  is that it allows the level  20   a  of the oil  20  to be observed during the filling/refilling process without removing the wick  34  or any associated components. It should be understood that the level  20   a  may not be visible at all times during the refilling process, but as the level  20   a  increases, the level  20   a  will become observable through the gap  32  to a user pouring oil  20  into the oil lamp  10 . In addition, due to the increasing cross-sectional area of the reservoir  12 , as described above, the fill rate (i.e., the rate at which the level  20   a  rises within the reservoir  12 ) actually decreases as long as a volumetric input rate of the oil  20  being added remains substantially constant during the filling or refilling process. Hence, a user can refill the reservoir by adding oil  20  at a relatively constant rate with much less concern that the oil  20  will suddenly overflow the rim  12   c  of the reservoir  12 . In short, observing the oil level  20   a  through the gap  32  during the filling or refilling process significantly reduces the risk of both overflowing and under filling the reservoir  12 .  
         [0031]     Another advantage is that the gap  32  provides a region around the flange  16  where the fragrance molecules of the oil  20  can be directly dispersed into the air. This eliminates the need for special diffusers or other devices.  
         [0032]     Yet another advantage is that the gap  32  permits the reservoir  12  to be filled without removing the wick and/or without special tools.  
         [0033]      FIG. 3  shows the wick holder  18  with wick material  34  placed in the wick holder  18 . The wick holder  18  includes a plurality of openings  36  to receive the oil  20  in the reservoir  12 . As previously discussed, the oil  20  wets the wicking material  34  through capillary action. The openings  36  can be located and spaced around the bottom portion of the wick holder  18  or can be formed in the wick holder  18  slightly above the bottom region. The openings  36  can also correspond and align with any openings that are formed in the clips  26  or inner ring  28  used to secure the wick holder with the reservoir  12 , as discussed above and illustrated in  FIGS. 2A, 2B , and  2 C.  
         [0034]     Although specific embodiments of and examples for the oil lamp and method of filling the oil lamp are described herein for illustrative purposes, various equivalent modifications can be made without departing from the spirit and scope of the invention, as will be recognized by those skilled in the relevant art. The teachings can apply to any type of oil lamp or other lamp, lantern, or device that uses a combustible liquid for fuel. Additionally, any method described above may include additional steps, omit some steps, and perform some steps in a different order than illustrated and/or otherwise described.  
         [0035]     The various embodiments described above can be combined to provide further embodiments. All of the above U.S. patents, patent applications and publications referred to in this specification are incorporated herein by reference. Aspects of the invention can be modified, if necessary, to employ devices, features, and concepts of the various patents, applications and publications to provide yet further embodiments of the invention.  
         [0036]     These and other changes can be made to the invention in light of the above detailed description. In general, in the following claims, the terms used should not be construed to limit the invention to the specific embodiments disclosed in the specification and the claims, but should be construed to include all reusable card configurations and methods that operate in accordance with the claims. Accordingly, the invention is not limited by the disclosure, but instead its scope is to be determined entirely by the following claims.