Patent Abstract:
Portable combustible fuel automatic drip coffee making apparatuses use combustible fuels such as propane, butane, white gasoline, and kerosene to heat water which can be alternatively used to make drip coffee, or for other requirements calling for heated water, depending on the selected position of a switching valve. The portability of these devices is self contained and hand transportable. The inventive units are designed to be user maintained with easily cleanable or replaceable parts, as well as designed for manufacturing. These units are configured based on the specific fuel being used, and some units are designed to be able to use a variety of fuels in the same unit.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This application is based on a provisional application Ser. No. 60/402,066 filed on Aug. 9, 2002. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a method for brewing coffee, and in particular, a method for brewing coffee by an automatic drip method, fully portable, and utilizing common combustible fuels in container form as the power source. 
   2. Description of the Related Art 
   Modern automatic drip coffee makers are well known, but all depend on external sources, which severely limits their portability. An exception is the battery powered variety, but these are so slow in operation as to be almost unacceptable in the marketplace. Furthermore, of all the truly portable coffee makers available, all are either coffee presses or percolators; none are of the automatic drip variety. As personal tastes for properly brewed coffee expand and refine, obviously the preferred brewing method is automatic drip, where the full flavor is extracted from the coffee bean without exposing the grounds to excessive temperatures, which would impair the true flavor of the coffee. 
   Accordingly, it is desirable to provide a truly portable automatic drip coffee maker, not reliant on external power sources, and operating within normal, expected preparation times. The present invention answers this need. It uses commonly available combustible fuels, uses the automatic drip method to make coffee (as does a home appliance type coffee maker), and is self-contained, hand-transportable, and not reliant on external power sources. 
   Portable coffee makers usable in remote locations, such as at camping sites, in recreational vehicles, or on boats are well known. Combustible fuels such as propane, butane, and mixtures as well as liquid fuels such as white gasoline and kerosene, are commonly available through retail outlets, and are used in portable stoves and other devices, such as sold by The Coleman Company. 
   However, there is a need for a fully portable, automatic drip coffee maker which does not require an electric power source. This invention fulfills this purpose, using one of the commonly available fuel sources, and further provides not only drip coffee, but hot water as well. 
   Moreover, the inventive coffee maker is designed and constructed to fulfill a further need to permit the easy and convenient removal and replacement of a water heating coil that can typically become fouled and clogged after prolonged use. 
   U.S. Pat. No. 61,454, issued to Plumb on Jan. 22, 1867, describes a portable oil-burning lamp stove useable for making coffee or water. 
   U.S. Pat. No. 368,340, issued to Kaplan on Aug. 16, 1887, describes a cooking stove using gas heat or an oil burner to heat water for making tea, coffee and hot water. 
   U.S. Pat. No. 1,041,822, issued to De Lima on Oct. 22, 1912, describes a portable coffee maker using an alcohol lamp for heating. 
   U.S. Pat. No. 3,133,536, issued to Knapp on May 19, 1964, describes a propane-heated lantern stove usable for making coffee. 
   U.S. Pat. No. 3,978,844, issued to Wilkens on Sep. 7, 1976, describes a portable propane heated cooking vessel. 
   U.S. Pat. No. 4,354,427, issued to Filipowicz et al. on Oct. 19, 1982, describes a coffee or tea-making apparatus using electrical heaters. 
   U.S. Pat. No. 4,757,754, issued to Welker on Jul. 19, 1988, describes a gas-heated coffee maker, but is not a portable device. 
   U.S. Pat. No. 5,123,335, issued to Aselu on Jun. 23, 1992, U.S. Pat. No. 5,233,914, issued to English on Aug. 10, 1993, and U.S. Pat. No. 5,274,736, issued to Rohr, Jr. on Dec. 28, 1993, describe coffee makers that are portable using a vehicle cigarette lighter to operate electrical heater elements. 
   U.S. Pat. No. 5,690,094, issued to Sheinfeld et al. on Nov. 25, 1997, describes a portable combustible gas-heated kettle. 
   U.S. Pat. No. 5,943,945, issued to Ishihara on Aug. 31, 1999, describes an electrically heated coffee maker. 
   U.S. Pat. No. 6,123,010, issued to Blackstone on Sep. 26, 2000, teaches a portable electrically heated coffee maker. 
   U.S. Pat. No. 6,257,227, issued to Harbin on Jul. 10, 2001, describes a coffee maker that uses heat provided by a barbeque grill. 
   U.S. Pat. No. 6,298,770, issued to Blankenship et al. on Oct. 9, 2001, describes a coffee maker using an elongated valve that is used to switch the water flow between a re-circulation setting, in which the water re-circulates through the heater and the reservoir, and a drip coffee setting, in which the water passes through the coffee grounds into the carafe. 
   None of the above devices teaches a completely portable, automatic drip coffee maker using combustible fuels. 
   None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed. Thus, a portable combustible gas fueled automatic drip coffee maker solving the aforementioned problems is desired. 
   SUMMARY OF THE INVENTION 
   The portable combustible fuel automatic drip coffee maker has two separate fluid streams, i.e., a combustible liquid fuel stream and a water stream. The fuel stream begins at a contained fuel supply, such as a refillable reservoir or replaceable container of either propane, butane, regular grade gasoline, white gasoline, kerosene, diesel fuel, naphtha, or even peanut oil, and ends as depleted combustion gases leaving a burner. The water stream includes two pathways: (1) a re-circulating pathway between a water reservoir and a water heater coil, and (2) a one-way drip coffee pathway from the hot water heater coil through a basket and filter containing coffee grounds into a carafe. The water heater coil is positioned directly above the burner in order that the heat from the combustion of the fuel is transferred to the water in the coil. 
   Accordingly, it is a principal object of the invention to provide a portable automatic drip coffee maker device that uses combustible fuel and additionally provides hot water. 
   It is another object of the invention to provide a portable automatic drip coffee maker device that uses a water heater coil easily removable and replaceable when fouled. 
   It is a further object of the invention to provide a portable automatic drip coffee maker device in which the water heater coil and burner are attached together as an assembly using a unique 3-arm support brace for strength and sturdiness. 
   It is yet a further object of the invention to provide a method of installing the burner and heater assembly into the housing using a unique clip structure. 
   It is still another object of the invention to provide liquid fuel sources contained in either refillable reservoirs or replaceable cylinders of either propane, butane, regular grade gasoline, white gasoline, kerosene, diesel fuel, naphtha or peanut oil. 
   It is an object of the invention to provide improved elements and arrangements thereof for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes. 
   These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an environmental, perspective left side view of a portable combustible gas fueled automatic drip coffee maker according to the present invention. 
       FIG. 2  is a front elevational view of the portable automatic drip coffee maker. 
       FIG. 3  is a right side elevational view of the portable automatic drip coffee maker. 
       FIG. 4  is a top plan view of the portable automatic drip coffee maker. 
       FIG. 5  is a cross-sectional view of the coffee maker as viewed from the right side. 
       FIG. 6  is a cross-sectional view of the coffee maker as viewed from the front. 
       FIGS. 7A and 7B  show a top plan view and a side view, respectively, of the combined water heater coil and burner assembly. 
   

   Similar reference characters denote corresponding features consistently throughout the attached drawings. 
   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Perspective front, side and top plan views of the inventive portable automatic drip coffee maker  10  are shown in  FIGS. 1-4 . The outer housing is made up of three main interlocking parts, the top  26 , the sides  34  and bottom  28 . Preferably these parts are made of a sturdy molded plastic material. Water reservoir  27  has a lid  74  hinged to the top of the housing that can be opened by grasping either of the grip tabs  46  and lifting the lid  74 . Side door  82  can be opened to access a hot water tap (hidden) to draw hot water from a reservoir. 
   The coffee maker  10  has two separate fluid streams, i.e., a fuel stream used to provide heat and a water stream to provide hot water or drip coffee. 
   As shown in the cross-sectional views of  FIGS. 5 and 6 , the fuel stream begins at a fuel cylinder  76 , e.g., a replaceable cylinder of either propane, butane, white gasoline, low octane gasoline, kerosene, diesel fuel, naphtha, or even peanut oil, and ends as combustion products emitted through apertures  32 , seen in  FIG. 7A , in the top of the burner  108  (FIG.  7 B). 
   At the top of the fuel cylinder  76  is a fuel valve  12 , e.g., a needle valve, which is adjusted using valve handle  14 . Fuel passes from the cylinder  76  through valve  12  into conduit  16 . Fuel conduit  16  is connected directly to the burner inlet conduit  18  where the fuel mixes with air in the aerating portion of the burner inlet. 
   The air enters the burner inlet conduit  18  through apertures  22  ( FIGS. 5 ,  7 A and  7 B) and the fuel-air mixture enters the burner assembly  20  near its center, and is distributed radially outwardly to the burner apertures  32  (FIG.  7 A). The air is drawn into the burner inlet line  18  by a partial vacuum created by the expansion of the fuel as it flows through a narrow conduit into a wider diameter conduit immediately upstream of the air inlet apertures  22 . The fuel-air mixture exiting the burner apertures undergoes combustion, giving off heat that is absorbed by the water flowing in the water heating coil  40 . A portion of the heat generated by the combustion is also absorbed by the carafe  90 . 
   In order to ignite the fuel during routine use of the coffee maker  10 , after partially opening fuel valve  12  to initiate fuel flow, a spark is produced by spark plug  88  ( FIG. 7A ) by depressing the igniter button switch  62 . 
   The water stream can flow through two possible pathways depending upon the position of the water switching valve  44  (FIGS.  1  and  5 ): (1) a recirculating pathway when the water switching valve  44  is pushed downward into the closed position (not shown); and (2) a drip coffee pathway when the water switching valve  44  is pulled upward in the open position as shown in FIG.  5 . Thus, the water switching valve handle  42  can be pulled up or pushed down depending upon whether the user wants to make drip coffee (i.e., the “drip coffee” mode) or to circulate hot water in the reservoir  27  (i.e., the “hot water recirculation” mode). A detailed cross-sectional view of the water switching valve  44  is shown in  FIG. 5 , in which the movable concave portion  94  of the valve  44  matches the contour of the stationary convex portion  96 , thereby forming a seal when the valve  44  is closed. 
   Hot water coming from the water heater coil  40  passes through the vertical inlet conduit  116  to the water switching valve  44 . In the “drip coffee” mode, the hot water passes through the slit-like opening in valve  44  into the space  86  in the top of the housing and into the basket  54  which contains a conventional filter, e.g., paper filter or metal mesh basket filter, holding coffee grounds. The filtered drip coffee then passes through the opening  56  into the carafe  90 , wherein the drip coffee is collected. Carafe handle  92  permits the user to hold the carafe  90 . Also, filter basket handle  52  is used to hold the filter basket  54 , and to remove and replace the spent coffee grounds. 
   Alternatively, when the water switching valve  44  is in the “hot water recirculating” mode, the hot water passes out of the valve  44  into reservoir  72 . After recirculation has taken place over a period of time, the water contained in the reservoir becomes sufficiently hot to use, e.g., for making tea. A reservoir tap  114 , shown in  FIG. 5 , is provided to permit the user to draw hot water from the reservoir. The hot water tap is accessed by opening the housing door  82 , shown in  FIGS. 1 and 5 . 
   In either mode, the water that leaves the bottom of the reservoir  27  passes through the reservoir outlet port  112  through a check valve  110 , e.g., an in-line ball check valve, to ensure flow only in one direction, and into the water heater coil  40 . 
   Features of the unique water heater coil and burner assembly  20  are shown in detail in  FIGS. 7A and 7B . A 3-arm support brace  50  serves to provide support for the carafe  90  as well as to securely hold the water heater coil  40  in a fixed spaced relationship with the burner  30 . The support brace  50  is made up of three pieces of stamped, bent metal strips that are riveted together. As a result, each of the three arms of the assembled, riveted support brace  50  are formed by two parallel portions of the stamped, bent metal strips, thus forming spaced dual strip arms. 
   The arms of the brace  50  radiate outwardly from a central opening  60  to the distal ends  70 . At the end of each arm is a permanent headed rivet  84  and two removable rivet pins held by retaining rings  100  and  102 . Single strip connectors  78  are held in place at their ends by the removable rivets. At the locations where the ends of the arms contact the sides of the burner  30 , tabs bent 90 degrees with respect to the direction of the arms are permanently fastened to the sides of the burner  30 , e.g., by soldering or welding. 
   Over a prolonged period of use of the coffee maker, when the internal surfaces of the water heating coil  40  become fouled and/or clogged because of accumulated deposits caused by using mineral-laden water or other water containing debris, the water heater can be removed as follows: The water reservoir  72  is drained; the water heater coil lines are disconnected from the reservoir  72 ; retaining rings  100  are removed from each arm of the support brace  50 ; and connectors  78  are lifted and rotated on the pivot provided by the inmost rivets to thereby allow the water heater coil  40  to be lifted up and away from the burner  30 . A new water heater coil can then be inserted in its place, the connectors  78 , and retaining rings  100  reconnected and attached, and the water heater inlet and outlet lines reconnected to the appropriate lines at the bottom of the reservoir  72 . 
   Referring to  FIGS. 5 ,  6  and  7 A, during initial assembly of the coffee maker  10 , the water heater and burner assembly  20  are installed into mounting clips  80  in the opening in the bottom portion of the housing  28  defined by the lip  24 . Three mounting clips  80  are distributed in and permanently held in the opening and are arranged to correspond to the positions of the distal portions of each of the arms  50 . The mounting clips  86  are made of stamped, bent metal strips. The portion of the mounting clips  80  that are permanently attached to the inside surface of the bottom opening of the housing  28  have an intermediate rounded portion. 
   At one end of each of the mounting clips  80  is a flat portion  48  that has two notches. The lower notch  58  accommodates the lower seamed edge  104  of the burner  30 . The upper notch accommodates the shaft of the rivet pin  84  of the respective arm of the support brace. Thus, the width of the flat portion  48  of the mounting clip  80  is approximately equal to the width of the space between the two parallel strips of the arm (see item  84  in FIG.  7 A). At the opposite end of each of the mounting clips  80  are two tabs  66  and  68 . Once the water heater and burner assembly  20  has been installed into the mounting clips, tab  68  is bent from a vertical position 90 degrees to a horizontal position into a small notch in the back  64  of the flat portion  48  of the clip to permanently lock the mounting clips  80  onto the burner  30  and brace  50  assembly. Tab  66  remains in a vertical position attached to the inside surface of the bottom of the housing. 
   It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.

Technology Classification (CPC): 0