Abstract:
A charcoal grill includes a mechanism whereby a user may adjust the vertical distance between a fuel grate and a cooking grid by rotating a control knob located on the surface of the charcoal grill. This mechanism provides a safer and more convenient way of adjusting the distance between the burning fuel and the food being cooked. The charcoal grill further includes a removable ash collector located at the bottom of the charcoal grill. To empty ash a user slides the ash collector out from its position at the bottom of the charcoal grill, empties it, and then replaces it to resume ash collection. Thus a user may conveniently dispose of ash without the use of an ash sweep tool and without interrupting operation. Furthermore the charcoal grill includes a metal skirt inside its lower shell, which protects the lower shell of the charcoal grill from excessive heat, lengthening its operational life.

Description:
FIELD OF THE INVENTION 
     The present invention relates to grills, specifically to grills which generate cooking heat by burning combustible fuel such as charcoal or wood. 
     BACKGROUND INFORMATION 
     Grills have become seemingly ubiquitous fixtures at outdoor social gatherings, especially in warmer weather. Generally, grills commonly known as charcoal grills, cook food over a burning bed of fuel bits such as charcoal, and often include a lid used to cover the food and keep it warm. 
     Known charcoal grills provide various means for controlling temperature inside a charcoal grill. Some employ air vents, which regulate the flow of air through the charcoal grill and thereby control the rate at which the charcoal burns. However, air vents quickly become too hot to adjust during operation of the charcoal grill. Furthermore, air vents alone provide only the most rudimentary means of temperature control. 
     Other known charcoal grills control cooking temperature by making the distance between the burning coals and the food being cooked manually adjustable. Such charcoal grills employ lift mechanisms that adjust the height of a charcoal bearing grate without interrupting the operation of the charcoal grill. However, the lift mechanism found in such charcoal grills requires the user to physically lift a vertical column onto a series of vertical notches. This method is both inconvenient and dangerous. The lifting action requires a user to exert a certain degree of force, and exposes the user to a risk that the applied vertical force may cause the charcoal grill to tip or fall. 
     Ash builds up quickly during operation of a charcoal grill and excessive accumulation of ash will extinguish the burning coals. Disposing of ash while charcoal is still burning can be both inconvenient and hazardous. Known charcoal grills solve this problem by requiring the use of a sweeping tool to force ash through openings at the bottom of the charcoal grill. However, requiring the use of any additional tool makes a charcoal grill less portable and less convenient to use. 
     During ordinary use, the body of a charcoal grill is quickly and repeatedly reheated to high temperatures. Often, the charcoal grill is also quickly cooled, by dousing it with water, for example. Such rapid and extreme changes in temperature over time eventually result in damage to the body of a charcoal grill, such as cracks or fading of color. To lengthen the operational life of a charcoal grill, the design of the charcoal grill must provide the body of the charcoal grill with some protection against excessive temperature changes. 
     Thus, there exists a need in the art for a safer and more convenient way of adjusting the distance between the burning fuel and the food being cooked. Furthermore, there exists a need in the art for a more convenient way of disposing of ash during operation that does not require the use of an ash sweep tool. There also exists a need in the art for a feature that protects the body of a grill from excessive temperature changes. 
     SUMMARY OF THE INVENTION 
     A grill according to an exemplary embodiment of the present invention provides a fuel grate lift mechanism, whereby a user may adjust the vertical distance between a fuel grate and a cooking grid by rotating a control knob located on the surface of the charcoal grill. This mechanism provides a safer and more convenient way of adjusting the distance between the burning fuel and the food being cooked. 
     An embodiment of the present invention further provides a removable ash collector located at the bottom of a charcoal grill. To empty ash a user slides the ash collector out from its position at the bottom of the charcoal grill, empties it, and then replaces it to resume ash collection. Thus a user may conveniently dispose of ash without the use of an ash sweep tool and without interrupting operation. 
     Furthermore a charcoal grill according to an embodiment of the present invention incorporates a metal skirt inside its lower shell, which protects the lower shell of the charcoal grill from excessive heat, lengthening its operational life. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 illustrates a front view of a grill according to an exemplary embodiment of the present invention. 
     FIG. 2 illustrates a side view of a grill according to an exemplary embodiment of the present invention. 
     FIG. 3 illustrates a liner of a grill according to an exemplary embodiment of the present invention. 
     FIG. 4 illustrates a perspective view of a grill according to an exemplary embodiment of the present invention. 
     FIG. 5 illustrates a lid of a grill according to an exemplary embodiment of the present invention. 
     FIG. 6 illustrates a top vent of a grill according to an exemplary embodiment of the present invention. 
     FIG. 7 illustrates a bottom shell of a grill according to an exemplary embodiment of the present invention. 
     FIG. 8 illustrates a cooking grid of a grill according to an exemplary embodiment of the present invention. 
     FIG. 9 illustrates a coal grate of a grill according to an exemplary embodiment of the present invention. 
     FIG. 10 illustrates a grate lift mechanism of a grill according to an exemplary embodiment of the present invention. 
     FIG. 11 illustrates a top view of the inside of a bottom shell of a grill according to an exemplary embodiment of the present invention. 
     FIG. 12 illustrates a vent ring of a grill according to an exemplary embodiment of the present invention. 
     FIG. 13 illustrates a side view of a bottom shell of a grill according to an exemplary embodiment of the present invention. 
     FIG. 14 illustrates an ash pan support wire of a grill according to an exemplary embodiment of the present invention. 
     FIG. 15 illustrates a cross-sectional view of an ash pan of a grill according to an exemplary embodiment of the present invention. 
     FIG. 16 illustrates the inside of a control knob of a grill according to an exemplary embodiment of the present invention. 
     FIG. 17 illustrates the front of a control knob of a grill according to an exemplary embodiment of the present invention. 
     FIG. 18 illustrates a grate lock of a grill according to an exemplary embodiment of the present invention. 
     FIG. 19 illustrates a side view of a grate lock of a grill according to an exemplary embodiment of the present invention. 
     FIG. 20 illustrates a top view of the inside of a bottom shell of a grill according to an exemplary embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Various aspects of the present invention will be described, and for purposes of explanation, specific configurations and details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to one skilled in the art that the present invention may be practiced without these specific details. Furthermore, well known features have been omitted or simplified in order to prevent obscuring the present invention. 
     FIG. 1 illustrates a front view of a grill according to an exemplary embodiment of the present invention. Referring to FIG. 1, a grill  100  according to an exemplary embodiment of the present invention generates heat for cooking food by burning fuel members such as, for example, charcoal, wood, or other suitable combustible fuel. Preferably, the main body of grill  100  is comprised of a bottom shell  140  movably coupled via a conventional hinge mechanism  210  to a lid  110 . Both bottom shell  140  and lid  110  may be formed from steel or other metal alloys. 
     FIG. 3 illustrates a liner of a grill according to an exemplary embodiment of the present invention. FIG. 7 illustrates a bottom shell of a grill according to an exemplary embodiment of the present invention. Referring to FIGS. 3 and 7, liner  300  made from aluminum or another metal alloy or from a porcelain coated metal alloy, is inserted into bottom shell  140  and rigidly coupled to flanged edge  710  inside bottom shell  140 . Liner  300  protects bottom shell  140  from excessive heat, reducing wear and fading of color. 
     Bottom shell  140  rests on, for example, four legs  120  made from aluminum or another metal alloy, which are rigidly coupled, for example, to a middle portion of bottom shell  140 . For increased portability, wheels  130  may be coupled to the bottom portion of two or more of legs  120 . Wire base  150  made, for example, from metal wire is coupled to a bottom portion of legs  120  and adds to the stability of legs  120  by counteracting the tendency of legs  120  to spread outward due to the weight of charcoal grill  100 . 
     One or more side tables  160  made, for example, from pressed wood board, are rigidly coupled to side table brackets  170  which are in turn laterally disposed and are, for example, rigidly coupled to legs  120  but may be rigidly coupled to bottom shell  140 . In alternative embodiments, side tables  160  or side table brackets  170  may be made collapsible using a conventional lockable hinge mechanism. A side table bracket  170  may have a meat probe receptacle  180  for storing, for example, a meat thermometer  190 . 
     In an exemplary embodiment of the present invention, one or more handles  115  made, for example, from plastic or any other poor conductor of heat, may be used for raising lid  110  away from bottom shell  140 . Handles  115  are rigidly coupled to and, for example, laterally disposed to, lid  110 . A top vent  410  is disposed at the approximate top of lid  110  and is manually adjustable to increase or decrease the flow of air through the inside of charcoal grill  100 . 
     FIG. 4 illustrates a perspective view of a grill according to an exemplary embodiment of the present invention. FIG. 5 illustrates a lid of a grill according to an exemplary embodiment of the present invention. FIG. 6 illustrates a top vent of a grill according to an exemplary embodiment of the present invention. Referring to FIGS. 4,  5 , and  6 , both lid  110  and top vent  410  are perforated with, for example, similar patterns of vent openings  510 ,  610 . Top vent  410  is movably coupled to the perforated area  510  of lid  110  such that each rotates with respect to the other along the same plane. Air flow through charcoal grill  100  may be increased by rotating top vent  410  until its vent openings  610  are substantially in line with corresponding vent openings  510  in lid  110 . Similarly, air flow may be blocked by positioning the corresponding vent openings  510 ,  610  so that they are not in line with one another. A top vent handle  125  made, for example, from plastic or any other poor conductor of heat, may be used to adjust top vent  410 . 
     FIG. 7 illustrates a bottom shell of a grill according to an exemplary embodiment of the present invention. FIG. 8 illustrates a cooking grid of a grill according to an exemplary embodiment of the present invention. FIG. 9 illustrates a coal grate of a grill according to an exemplary embodiment of the present invention. Referring to FIGS. 7,  8 , and  9 , cooking grid  800  lies inside bottom shell  140 , supported by, for example, a ledge formed by a flanged edge  710  of bottom shell  140 . Cooking grid  800  may have a hinged portion  810  that may be raised or lifted, permitting access to fuel grate  900  in order to, for example, add more fuel without interruption of cooking. 
     Both cooking grid  800  and fuel grate  900  are constructed, for example, from pieces of evenly spaced metal wire. Ash formed by the burning fuel on fuel grate  900  falls through the spaces between the metal wire comprising fuel grate  900  to an opening in the lower portion of bottom shell  140  underneath fuel grate  900 . The fuel burned on fuel grate  900  may be, for example, charcoal but may also be another combustible material such as, for example, wood. 
     FIG. 9 illustrates a coal grate of a grill according to an exemplary embodiment of the present invention. FIG. 10 illustrates a grate lift mechanism of a grill according to an exemplary embodiment of the present invention. FIG. 11 illustrates a top view of the inside of a bottom shell of a grill according to an exemplary embodiment of the present invention. Referring to FIGS. 9,  10 , and  11 , fuel grate  900  lies on grate lift wires  1010   a,    1010   b  inside bottom shell  140  disposed underneath and in a plane substantially parallel to cooking grid  800 . Grate lift wires  1010   a,    1010   b  according to an embodiment of the present invention, slide freely along the bottom of fuel grate  900 . U-shaped wires  910  underneath fuel grate  900  act as hooks for grate lift wires  1010   a,    1010   b.  When grate lift wires  1010   a,    1010   b  are in, for example, the high position, they hook onto U-shaped wires  910  to prevent the fuel grate  900  from tipping during operation of the grate lift mechanism. 
     FIG. 12 illustrates a vent ring of a grill according to an exemplary embodiment of the present invention. FIG. 13 illustrates a side view of a bottom shell of a grill according to an exemplary embodiment of the present invention. Referring to FIGS. 12 and 13, vent ring  1200  located at the lower portion of bottom shell  140  functions in a manner similar to top vent  410 . A cylindrical lower portion of bottom shell  140  is perforated with bottom shell vent openings  1310 . A vent ring  1200 , perforated with a matching pattern of vent ring openings  1210 , is movably coupled to the cylindrical lower portion of bottom shell  140 . By rotating vent ring  1200 , bottom shell vent openings  1310  and vent ring openings  1210  may be moved into and out of line with each other, respectively increasing or decreasing air flow through grill  100 . Referring to FIGS. 2 and 4, a vent ring handle  220  made, for example, from plastic or any such poor conductor of heat, may be used to adjust vent ring  1200 . 
     FIG. 14 illustrates an ash pan support wire or a grill according to an exemplary embodiment of the present invention. Referring to FIGS. 1,  2 , and  14 , ash pan support wire  230  is coupled to bottom shell  140  by flexing the ash pan support wire  230  and guiding the ends of the wire through holes in bottom shell  140 . 
     FIG. 15 illustrates a cross-sectional view of an ash pan of a grill according to an exemplary embodiment of the present invention. Referring to FIGS. 1 and 15, ash pan  135  has a flanged rim  1510  via which ash pan  135  rests on ash pan support wire  230  and along which ash pan  135  slides freely. To secure slidable ash pan  135  to ash pan support wire  230  the diameter of ash pan  135  is embossed to be thicker near ash pan handle  145 , creating a snug fit with ash pan support wire  230 . Alternative methods for securing ash pan  135  to ash pan support wire  230  may also be employed, such as a spring activated catch. 
     Ash pan  135  may be made, for example, from aluminum or another metal alloy. Ash pan  135  is placed directly under the open bottom portion of bottom shell  140  and collects ash as it falls through fuel grate  900  into open bottom portion  720  depicted in FIG.  7 . 
     Ash pan handle  145  may be made, for example, from plastic or any such poor conductor of heat and may be used to slide ash pan  135  out from ash pan support wire  230  in order to empty ash pan  135 . Once emptied, ash pan  135  slides back into place along ash pan support wire  230 . Thus ash pan  135  provides a convenient way of disposing of ash and debris without interrupting operation of grill  100 . 
     Fuel grate  900  may be lifted and lowered by grate lifting mechanism  1000  as is depicted in FIG.  10 . Grate lift mechanism  1000  consists of, for example, a grate lift wire  1010   a  permanently coupled to one end of grate lift wire arm  1020   a.  Another end of grate lift wire arm  1020   a  is pivotally connected to one end of a left grate lift link  1030   a,  the other end of which is pivotally connected to one end of a grate lift pivot arm  1040 . Pivotally connected to the other end of a grate lift pivot arm  1040  is one end of grate lift link  1030   b,  which is in turn permanently connected to one end of grate lift wire arm  1020   b.  The other end of grate lift wire arm  1020   b  is pivotally connected to one end of a grate lift wire  1010   b.    
     Referring to FIG. 11, grate lift wire retainer brackets  1110  made, for example, from aluminum or another metal alloy, are rigidly coupled to bottom shell  140  and hold grate lift wires  1010   a,    1010   b  in position while allowing grate lift wires  110   a,    1010   b  to rotate freely. 
     FIG. 16 illustrates the inside of a control knob of a grill according to an exemplary embodiment of the present invention. FIG. 17 illustrates the front of a control knob of a grill according to an exemplary embodiment of the present invention. FIGS. 1,  16  and  17  illustrate control knob  155 . Referring to FIGS. 16 and 10, a control knob shaft  1610  is rigidly coupled to, for example, a notched opening  1040   a  at center of grate lift pivot arm  1040 . Notched opening  1040   a  matches grooved portions of control knob shaft  1610  such that rotation of control knob  155  rotates grate lift pivot arm  1040 . 
     Referring to FIG. 1, rotation of control knob  155  to, for example, high position  165   a,  causes grate lift pivot arm  1040  to similarly rotate about its center in the same direction. Grate lift links  1030   a,    1030   b  are pivotally connected to opposite ends of grate lift pivot arm  1040 . Thus rotation of grate lift pivot arm  1040  about its center necessarily pulls both grate lift links  1030   a,    1030   b  in opposite directions and towards one other. Grate lift links  1030   a,    1030   b  acting as levers, raise grate lift wires  1010   a,    1010   b  upon which fuel grate  900  rests. Thus fuel grate  900  is lifted closer to cooking grid  800  intensifying the cooking heat. 
     FIG. 18 illustrates a grate lock of a grill according to an exemplary embodiment of the present invention. FIG. 19 illustrates a side view of a grate lock of a grill according to an exemplary embodiment of the present invention. FIG. 20 illustrates a top view of the inside of a bottom shell of a grill according to an exemplary embodiment of the present invention. Grate lock  1800 , according to an embodiment of the present invention, is a mechanism for locking grate lift wires  1010   a  and  1010   b  in position. Referring to FIGS. 18,  19 , and  20  there are openings at both ends of grate lock  1800  through which a control knob shaft  1610  is inserted. One end of the grate lock housing  1810  has small grate lock perforations  1820 . Inside grate lock housing  1810  a grate lock spring  1840  pushes a rotatable grate lock index disc  1830  firmly against the inside portion of the grate lock perforations  1820  of grate lock housing  1810 . Grate lock index disc teeth  1830   a  fit into grate lock perforations  1820  in grate lock housing  1810 . 
     Control knob shaft  1610  is inserted through openings in grate lock housing  1810  and notched opening  1830   b  in the center of grate lock index disc  1830 . Notched opening  1830   b  matches grooved portions of control knob shaft  1610  such that rotation of control knob  155  rotates grate lock index disc  1830 . 
     FIG. 18 depicts grate lock  1800  in a locked position. Grate lock index disc teeth  1830   a  are engaged, jutting through grate lock perforations  1820 . To disengage grate lock index disc teeth  1830   a  force must be applied to teeth  1830   a  sufficient to compress grate lock spring  1840 . Once grate lock index disc teeth  1630   a  are disengaged from grate lock perforations  1820 , grate lock index disc  1830  is free to rotate. 
     To raise fuel grate  900 , a user must first push control knob  155  forward to disengage grate lock  1800 . Then, a user must rotate control knob  155  in the appropriate direction as indicated on control panel  165 . As has already been described, this action rotates the grate lift pivot arm  1040 , which pulls the grate lift links  1030   a,    1030   b  towards each other and in opposite directions, raising grate lift wires  101 a and  1010   b  upon which fuel grate  900  rests. A user must continue to rotate control knob  155  until grate lock index disc teeth  1830   a  engage with grate lock perforations  1820 , placing the grate lock  1800  in a locked position and thus holding control knob  155  and grate lift wires  1010   a,    1010   b  in locked position. 
     To lower fuel grate  900  a user must first push control knob  155  forward to disengage grate lock  1800 . Then a user must rotate control knob  155  in the appropriate direction as indicated by control panel  165 . Rotation of control knob  155  combined with the weight of fuel grate  900  rotates grate lift pivot arm  1040  and pushes grate lift links  1030   a,    1030   b  in opposite directions and away from one another, further causing grate lift wires  1010   a  and  1010   b  to fall back to a lower position. This action continues until grate lock index disc teeth  1830   a  engage with a set of corresponding grate lock perforations  1820  placing grate lock  1800  in a locked state.