CROSS-REFERENCE TO RELATED APPLICATIONS
 The benefit of the filing date of U.S. provisional patent application Ser. No. 60/592,661 filed Jul. 30, 2004 entitled PORTABLE FIRE PIT, is hereby claimed, and the specification thereof is incorporated herein by this reference.
FIELD OF THE INVENTION
 The present invention relates generally to a fire pit, and particularly to a portable fire pit that can be transported easily and stored compactly.
BACKGROUND OF THE INVENTION
 Many people enjoy an open, outdoor fire, such as at a campground. In many situations, however, it is necessary or desirable to provide good protection against the fire spreading. It is commonly known to use a fire ring or fire pit to help contain the fire. Such a conventional fire ring often consists of nothing more than a ring or hoop of metal placed upon the ground to allow combustible material, such as wood or charcoal, to be placed in the middle of the ring. While this works well at a campground, the fire ring is not particularly well-suited for use in one's backyard or for moving from place to place. It is also not well-suited to use, for example, on the back deck of a home.
 As an alternative to the simple fire ring, one can build a fire pit with substantially upright sides to provide the kind of protection that might be desirable for use near homes. In such a construction, the fire pit typically includes metal screens located in the sides to provide protection against the fire spreading, while still allowing people to enjoy seeing the fire through the screens. Unfortunately, this type of construction can be somewhat bulky, can be difficult therefore to move from place to place, and can take up excess of space in storage.
 Accordingly, it can be seen that a need exists in the art for a portable fire pit which can provide good protection against the spread of a fire, which can be transported easily from place to place, which can be made compact for storage or transport, and yet which can provide significant fire protection for use near homes. It is to the provision of such a portable fire pit the present invention is primarily directed.
SUMMARY OF THE INVENTION
 Briefly described, in a first preferred form the present invention comprises a portable fire pit having a base for supporting and containing combustible material and a plurality of (optional) legs for supporting the base above the ground or other surface. The portable fire pit further comprises a plurality of fire screens movably mounted to the base for movement between a first, compact position for transport and storage of the portable fire pit and a second, extended position in which the screens are substantially upright to contain the fire. Each of the fire screens preferably comprises a frame and a wire screen mounted therein. Preferably, the fire screens are movably mounted to the base using sliding hinges and guides and in the second, extended position the fire screens are maintained in the upright position by the guides.
 Described in another way, the portable fire pit of the present invention comprises a base for supporting and containing combustible material and a plurality of fire screens movably mounted to the base for movement between a first, compact position for transport and storage of the portable fire pit and a second, extended position in which the screens are substantially upright to contain the fire.
 Optionally, the screens are rotatably mounted to the base. In a preferred form, the screens are rotatably mounted to the base using sliding hinges or similar. Advantageously, guides can be mounted to the base to support the screens in the extended, upright position. Also, the portable fire pit can be fitted with a plurality of folding legs mounted to the base for supporting the base above the ground or other surface.
 The portable fire pit can also be provided with an ash removal door mounted to or formed in the base to allow the convenient removal of accumulated ash. The portable fire pit can be a polygon in overall shape, wherein, for example, the base is rectangular with four sides and wherein the plurality of screens comprise four screens, with each screen comprising a screen frame supporting a wire screen therein.
 The present invention has numerous advantages, including the compactness and the suitability for transport and storage. Also, while the fire pit encloses the fire with a plurality of fire screens for preventing the fire from spreading, the fire pit also has legs for preventing the fire pit from burning a surface beneath it. Moreover, the fire pit can be assembled and disassembled quickly and easily without the use of fasteners or tools.
 These and other aspects, features and advantages of the invention will be understood with reference to the drawing figures and detailed description herein, and will be realized by means of the various elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following brief description of the drawings and detailed description of the invention are exemplary and explanatory of preferred embodiments of the invention, and are not restrictive of the invention, as claimed.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
 FIG. 1 is a perspective view of a portable fire pit according to an exemplary embodiment of the present invention, shown as erected for use.
 FIG. 2 is a top view of a base portion of the fire pit of FIG. 1.
 FIG. 3 is a bottom view of the base portion of FIG. 2 and showing legs folded up against the base portion.
 FIG. 4 is a front elevation view of a fire screen panel portion of the fire pit of FIG. 1.
 FIG. 5 is a perspective view of a sliding hinge portion of the fire pit of FIG. 1, shown with one panel in the compact configuration and another panel in an extended upright position.
 FIG. 6 is a perspective view of the fire pit of FIG. 1 in a compact arrangement.
 Referring now to the drawing figures, in which like reference numbers refer to like parts throughout the several views, preferred forms of the present invention will now be described by way of example embodiments. It is to be understood that the embodiments described and depicted herein are only selected examples of the many and various forms that the present invention may take, and that these examples are not intended to be exhaustive or limiting of the claimed invention. Also, as used in the specification including the appended claims, the singular forms "a," "an," and "the" include the plural unless the context clearly dictates otherwise. Ranges may be expressed herein as from "about" or"approximately" one particular value and/or to "about" or "approximately" another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent "about," it will be understood that the particular value forms another embodiment.
 FIG. 1 shows a portable fire pit 10 according to an exemplary embodiment of the present invention. Preferably, the fire pit 10 includes a base 12, a plurality of legs 14, 16, 18, and 20 for supporting the base above the ground or other surface, and one or more screens or panels, preferably including side screens 22, 24 and end screens 26, 28, for containing the fire within the fire pit. When the fire pit 10 is in this assembled or erected configuration as shown in FIG. 1, the side screens 22, 24 and the end screens 26, 28 are upright and generally perpendicular to the base 12. The side screens 22, 24 are generally parallel to one another and generally perpendicular to and abut the end screens 18, 20. Thus, the base 12 and the screens 22, 24, 26, and 28 form a generally rectangular box-like structure with an interior chamber for containing a fire.
 In the depicted embodiment, the base 12 itself has sidewalls 30, 32, 34, and 36, for creating a generally rectangular, pan-like structure for containing combustible material, such as wood, charcoal, or other suitable combustible material for providing a fire therein. Thus, in the depicted embodiment, the base 12 resembles an open, rectangular box with four corners. Preferably, the base is constructed of a fire-resistant or fire-proof material, such as for example, a metal such as cast aluminum or sheet steel, although those skilled in the art will understand that various other non-combustible materials can be employed as well. In one exemplary embodiment, the base has dimensions of approximately 20''×20''×4'', although those skilled in the art will understand the base can have various shapes and/or sizes without departing from the scope of the present invention.
 Optionally, the base 12 includes an ash removal door 40 for releasing ash built up by the fuel as it is consumed, as seen more clearly in FIG. 2. The ash removal door 40 can be mounted to or formed in the base 12 to allow the convenient removal of accumulated ash. The ash removal door 40 can operate by a variety of mechanisms, such as for example, the door can be a sliding door, or the door can be a hinged door fastened shut with a latch that can be manually opened. Those skilled in the art will understand that various other forms of doors or openings within the base 12 can be employed as well so as to remove the ash from the fire pit 10 without having to turn the pit upside down to dump out the ash.
 As shown in FIG. 3, preferably four legs 14, 16, 18, and 20 support the base 12 of the fire pit 10, although those skilled in art will understand that any number of legs can be used so as to adequately support the fire pit, or even no legs can be used. In such an alternative embodiment, the base 12 could set directly on the ground without legs, although preferably the fire pit 10 includes legs so as to support the base 12 some distance above the ground or other surface in order to prevent the base from burning surface beneath it. The legs can be short, and thus, the fire pit 10 would sit close to ground for use at a campsite, for example. Or, the legs can be tall, and thus, the fire pit 10 would sit farther from ground for use on a deck or patio, for example. As an alternative to legs, the base 12 could be provided with an integral peripheral stand that supports the rest of the base above the ground.
 For ease of compactness and portability, the legs 14, 16, 18, and 20 can be pivotally mounted to the base 12 or constructed to fold up under the base. For example, the legs 14, 16, 18, and 20 can be configured similar to the legs of a folding card table, having a hinge that locks the legs in place in an extended position. Optionally, the legs can be extendible so that they provide more or less clearance between the base 12 of the fire pit 10 and the surface beneath it. Those skilled in the art will understand that legs can have various other configurations and still be in the scope of the present invention.
 In the depicted embodiment, four panels or fire screens 22, 24, 26, and 28 are movably mounted to the base 12 for movement between a first, compact position for transport and storage of the portable fire pit and a second, extended position in which the screens are substantially upright to contain the fire. Preferably, each screen is sized and shaped to fit within the base 12 of the fire pit so that they can lay substantially flat in their compact, folded position and to contain embers within the fire pit when they in the extended, generally upright position. The fire screens or panels can be generally rectangular, with dimensions approximately equal to the dimensions of the base so that the screens can lay substantially flat in the base.
 As best seen in FIGS. 4 and 5, each of the fire screens or panels can comprise a frame 50 and a wire mesh screen 52 mounted in the frame. Preferably, the frame 50 has an upper portion 54 having the mesh screen 52 therein, and a lower portion 56 secured to the base 12 when the screen is upright and also when the screen is in its compact position. The lower portion 56 of the frame 50 has an undercut region 58 defined between a shoulder 60 of the frame 50 and a pin or stub 62 extending laterally from the frame. Preferably, there is an undercut region 58 on opposing sides of the frame 50 sized and shaped so as to clear a guide element 72 when the panel is moved from its compact position to its upright position.
 Preferably, the fire screens are movably mounted to the base 12 using sliding hinges 70, which include guides 72 mounted to or formed within the base of the fire pit 10, such that when the screens are in an extended position, the fire screens are maintained in the upright position by the guides. As seen more clearly in FIG. 5, a pair of guides 72 is located proximate a corner of the base 12. Preferably, each guide 72 is an elongated U-shaped guide having a channel 74 therein for constraining the pin 62 and for holding the fire screen in an upright, erect position. The channel is divided by a shelf or divider 76. Thus, the portion of the channel between the base 12 and the shelf 76 constrains the pin, while the portion of the channel above the shelf provides a slot for receiving the frame 50 of the fire screen. The shelf 76 provides a seat for the shoulder 60 of the frame 50 when the fire screen is in its upright position, as well as provides an upper limit for the translational movement of the pin 62.
 Preferably, the guide 72 is constructed of a durable, fire proof or fire resistant material such as steel, and welded to the base 12, although those skilled in the art will understand that the guide can be constructed of various materials and secured to base in a variety of manners. Additionally, the guide 72 can have various other configurations so as to hold a fire screen in an erect or upright position.
 The pin 62 rotates about a pivot axis 78. Additionally, this pivot axis moves translationally with the pin as the pin is moved towards or away from the shelf 76. Thus, to move a fire screen, such as fire screen 22, from its compact position to its upright position, the screen, while remaining generally parallel to the base 12, is moved upwards towards the shelf 76 until the pin 62 engages the shelf. The screen 22 can be rotated about the axis 78 until the shoulder 60 of the frame 50 clears the top of the guide 72. The portion of the screen above the shoulder 60 can slide down into the channel until the shoulder 60 rests on the shelf 76. Thus, gravity helps secure the frame of the fire screen in its upright position, as shown by screen 26 in FIG. 5. Notably, the user can quickly and easily assemble and disassemble the fire pit 10 without the use of fasteners or tools.
 Preferably, there are a total of eight guides 72 within the base 12 of the fire pit 10, two of which are located at each corner as depicted in FIG. 5, although those of skill in the art will understand that a single guide or multiple guides can be used to secure each fire screen in an erect, upright position. In the depicted embodiment, the dimensions of the undercut region 58, the height of the guide 72 relative to the base, the height of the shelf 74 relative to the base, and the distance between the guide and the corner of the base 12 are all relatively precise. Those skilled in the art will understand that there can be various modifications to the present invention, such as including a first guide for constraining the pin and a second guide for securing the frame in an upright position. Thus, the pin can be longer or shorter than what is shown in the depicted embodiment. Additionally, some of the guides can be located in the corners of the base, while other guides are not. Moreover, the pin could be omitted from the device such that the fire panels are completely removable from the fire pit. These modifications are just some of the many modifications that can be made to the fire pit while still being within the scope of the present invention.
 Optionally, the fire pit 10 includes a lid 80. The lid 80 is a generally rectangular box-like structure for enclosing the top of the fire pit 10. In one example embodiment, the lid has dimensions of approximately 24''×24''×2'', although those skilled in the art understand that the lid can be of various shapes and sizes, and still be within the scope of the present invention. Preferably, the lid 80 includes a pair of removable handles 82 and 84. The lid 80 can include tracks or channels on opposing sides for inserting and locking handles 82 and 84 therein. For example, the lid 80 can be placed on the ends of the upright screens so as to enclose the fire pit, and when the lid is to be removed, the user can insert handles 82 and 84 into their respective tracks to lift the hot lid without using "potholders" or some other insulating device to protect the user from the heat of the lid.
 Additionally, when the screens are in the compact position within the base 12, the lid 80 can slide over the base 12 so as to provide a compact box for securely containing the contents during transport and storage of the fire pit. Optionally, the lid 80 includes a locking mechanism for securing the lid to the base 12 in the compact position. Also optionally, the handles 82 and 84 can be mounted to the lid 80 so as to provide an easier way for the user to carry the compact unit.
 Thus, to configure the fire pit 10 from its compact arrangement, the user removes the lid 80 of the compact unit from the base 20. The user also unfolds the legs 14, 16, 18, and 20 of the base 20 if so desired and sits the fire pit 10 on the desired surface. The user lifts the top fire screen panel 22 up, while keeping the panel substantially parallel to the base 12, until the pin 62 abuts the shelf 76. The user rotates the panel about 90° and then slides the frame 50 of the fire screen 22 down into the channel 74 of the guide 72 until the shoulder 60 rests on the shelf 76. The user repeats these steps with the other three fire screens. Once erected, the user can make a fire in the fire pit 10. Optically, the user can place the lid on the upper ends of the fire screens so as to keep debris from getting into the fire.
 While the invention has been described with reference to preferred and example embodiments, it will be understood by those skilled in the art that a variety of modifications, additions and deletions are within the scope of the invention, as defined by the following claims.