Abstract:
A modular outdoor barbeque grill and firepit is constructed of artificial stone-like slab members, which permit a uniform construction method by utilizing only a single block with a universal joint configuration to create an easily assembled, disassembled, re-assembled, and inexpensively manufactured product. Simple variation in the slab members&#39; length, as well as relocation of the joint permits tremendous versatility of product design without increasing complexity of assembly. Slab members are cast of air-entrained concrete in elastomeric molds for reduced density and lighter weight members, which have advantageous thermal properties, exhibit greater longevity in adverse weath conditions, and may be so formed with pigments to resemble stone, brick, or decorative mosaic tile. The ease of construction by the design of this invention also permits quick transition between a backyard fire pit and a barbeque grill with a sophisticated appearance.

Description:
[0001]    This application claims priority on Provisional U.S. Patent Application Ser. No. 61/128,531, filed May 22, 2008, the disclosures of which are incorporated by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to products made from artificial stone, and particularly to a modular firepit and outdoor grill constructed of artificial stone slab members, and more particularly, one which has a uniform construction method utilizing a single block to be easily assembled, disassembled, re-assembled, and inexpensively manufactured. 
       BACKGROUND OF THE INVENTION 
       [0003]    Stone firepits and barbeque grills are frequently found in outdoor locations where their durability and aesthetics permit containment of a fire for recreational purposes, such as for campers at campsites and parks, as well as public and private outdoor entertainment areas. Most of such firepits or grills are made from real stone and many are consolidated into a structural object by adhering the stone elements with the use of cement or concrete binder. Both the weight of such assembled firepits and grills and the complexity of the necessary assembly process do not lend them to be relocated either through disassembly or by transporting while fully assembled. 
         [0004]    The ability to have a product which appears to be made of stone and has a configuration visually similar to a real stone fire/barbeque pit, but which can be easily assembled and disassembled has value for end users wishing the benefits of a stone fire/barbeque pit without having the limitations of non transportability. 
         [0005]    Such an advantageous product has thus far been unavailable. One invention attempting to fulfill those needs is shown by U.S. Pat. No. 5,186,161 to Shumock. The Shumock invention is for a modular fireplace, and as described, it utilizes fire blocks with interlocking joints. While the modular nature of the Shumock invention permits transportability, the ease of relocation is severely hampered by the complexity of the various different joints utilized for the blocks, and by the multitude of various shaped and sized blocks required to construct the Shumock fireplace. In addition, there is no versatility in the end-product, in that only one unique fireplace configuration is attainable, and furthermore, it has limited adaptability to alternatively serve as an outdoor grill. 
         [0006]    In order for such a modular fireplace to realistically be transportable, a simpler means of assembly needed to be created. The problems of the prior art are solved herein with novel design which permits assembly of a firepit or grill with only a single configuration of block. 
       SUMMARY OF THE INVENTION 
       [0007]    A fire barbeque pit is assembled from a series of artificial stone slabs formed from concrete which has been surface pigmented with particles of a metal oxide to mimic the appearance of stone. The slabs have interlocking male and female grooves which allow for perpendicular inter-locking placement of the slabs. The indentations allow for the slabs to overlap at their extremities creating a stable structure which can be assembled and disassembled without the use of cement or binding concrete to consolidate the structure. This allows for easy on-site assembly, subsequent disassembly and transportation from the site after use. 
         [0008]    In one preferred embodiment of the invention the slabs of the present invention have a body portion with top surface, bottom surface and a pair of side surfaces that extend from the top surface to the bottom surface. The slab formed by these surfaces has a generally rectangular or square cross section. The slab also has a first end portion and a second end opposite the first end. Each of the end portions is separated from the body portion by at least one recessed portion. The recessed portion is designed to mate with a recessed portion of a second slab that is positioned transverse to the first slab thereby to removably interlock to the slabs. In forming the barbecue of the present invention, there is a base slab where there are recesses on the top surface and there is a bottom surface that preferably extends from said first end to said second end without a recess portion. This will provide a flat surface for the barbecue to rest. Similarly, the top slab has a recess on the bottom surface with the top surface relatively flat or finished. The lengths of the slabs can vary depending on how large a barbecue grill is desired. 
       OBJECTS OF THE INVENTION 
       [0009]    It is an object of this invention to provide a modular fire pit which may be assembled and disassembled for relocation. 
         [0010]    It is a further object of this invention to provide a modular barbeque grill which may be assembled and disassembled for relocation. 
         [0011]    It is another object of this invention to provide an interlocking block design which permits construction utilizing a minimum number of different shaped and sized blocks to reduce complexity of the assembly process, disassembly, and re-assembly. 
         [0012]    It is another object of this invention to provide a block which is constructed of a lightweight material. 
         [0013]    It is another object of this invention to provide an aesthetically appealing block which may be adapted to resemble stone, brick, or decorative mosaic tile. 
         [0014]    It is another object of this invention to provide a block construction from lightweight concrete. 
         [0015]    It is another object of this invention to provide a block with a joint design that may be utilized on every block of the assembly. 
         [0016]    It is another object of this invention to provide a design which permits easy adjustment of the height of the fire area. 
         [0017]    It is another object of this invention to provide a design which permits easy adjustment of the height of the grilling area. 
         [0018]    It is another object of this invention to provide a design which permits easy adjustment of the height of a block fume hood. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  is a perspective view of a barbecue grill with a telescoping block fume hood, identifying the various blocks required for its construction. 
           [0020]      FIG. 2  is a perspective view of a barbecue grill with a back splash block, identifying the various blocks required for its construction. 
           [0021]      FIG. 2A  is a cutaway view of one wall of an embodiment of the current invention, displaying grill support dowel pins. 
           [0022]      FIG. 3  is a perspective view of a fire pit of the current invention, identifying the various blocks required for its construction. 
           [0023]      FIG. 4  is a perspective view of a fire pit according to the current invention, which has an alternative top course of upper blocks without exposed top notches. 
           [0024]      FIG. 5  is a top view of a top grill grate of the current invention. 
           [0025]      FIG. 6  is a top view of a bottom grill grate of the current invention. 
           [0026]      FIG. 7  is a perspective view of the second embodiment of the current invention where it is fitted with a removable unitary fume hood. 
           [0027]      FIG. 7A  is a front view of the removable unitary fume hood. 
           [0028]      FIG. 7B  is a side view of the removable unitary fume hood. 
           [0029]      FIG. 7C  is a top view of the removable unitary fume hood. 
           [0030]      FIG. 8A  is a series of three views describing a plain slab member (block A) of the current invention. 
           [0031]      FIG. 8B  is a series of three views describing a slab member (block B) of the current invention. 
           [0032]      FIG. 8C  is a series of three views describing a spacer slab (block C) of the current invention. 
           [0033]      FIG. 8D  is a series of three views describing a transition slab member (block D) of the current invention. 
           [0034]      FIG. 8E  is a series of three views describing a splash slab member (block E) of the current invention. 
           [0035]      FIG. 8F  is a series of three views describing block F of the current invention. 
           [0036]      FIG. 8G  is a series of three views describing a short slab member (block G) of the current invention. 
           [0037]      FIG. 8H  is a series of three views describing a variable length slab member (block H) of the current invention. 
           [0038]      FIG. 8I  is a series of three views describing a shorter variable length slab member (block I) of the current invention. 
           [0039]      FIG. 8J  is a series of three views describing a shortest variable length slab member (block J) of the current invention. 
           [0040]      FIG. 8K  is a series of three views describing short plain slab member (block K) of the current invention. 
           [0041]      FIG. 9A  is a perspective view representing an alternative notch configuration of the current invention, which uses a cylindrical protrusion and indentation. 
           [0042]      FIG. 9B  is a perspective view representing an alternative notch configuration of the current invention, which uses a V-shaped protrusion and indentation. 
           [0043]      FIG. 9C  is a perspective view representing a third alternative notch configuration of the current invention. 
           [0044]      FIG. 9D  is a perspective view representing a fourth alternative notch configuration of the current invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0045]    The design of the basic member of this invention provides for an easily assembled and disassembled fire pit or barbeque grill. The design also readily lends itself to adding additional features which may be marketed separately or as a more complete package. 
         [0046]    A fully featured barbeque grill  10  is shown in the photograph of  FIG. 1 , and a basic fire pit  13  is shown in  FIG. 3 . Construction of the fully featured barbeque grill  10  shown in  FIG. 1  can be achieved by adding blocks to the fire pit of  FIG. 3 , which dictates that an initial discussion of one possible embodiment of this invention should be the fire pit  13 . 
         [0047]    There are many possible fire pit shapes that can be formed from the blocks of the current invention, such as, but not limited to, a fire pit whose footprint forms a V-shape, a C-shape, a U-shape, a rectangle, or other polygon shape, or even a curved shape. To be illustrative of such possibilities, a rectangular fire pit  13  is described. 
         [0048]    The fire pit  13  shown in  FIG. 3  may be constructed using multiple copies of the same formed block shape. The fire pit  13  is created by assembling the blocks to create a series of tiers, or using brick laying terminology, a series of courses. The number of course utilized may be determined according to the needs of the user. To have a shallow height fire pit  13  which may be more easily enjoyed or viewed while sitting on the ground or sitting in a chair, fewer courses may be utilized. To accommodate a larger fire created through use of greater amounts of fuel, the height of the fire pit  13  may be increased by using one or more additional courses. Also, to comfortably accommodate a deeper fire which may be desired for users who may intend to be standing around the fire pit  13 , additional courses may be addded to produce a fire pit  13  of suitable height. The length of the slabs can also vary depending on how large of a fire pit a user desires. For large gatherings of family or friends, a fire pit with a greater permimeter may be desired, or perhaps even a fire pit perimeter formed to have a rectangular footprint, rather than a square footprint, might be more desirable. 
         [0049]    A block may be formed, in a preferred embodiment, with concrete poured into elastomeric molds. The concrete generally will be allowed to set for 10-28 days and then be removed from the mold. The molds may be covered with one or more pigments to produce blocks, and ultimately a fire pit or grill, of a desired color or shade. The surface pigment may include, but is not limited to: particles of metal oxide; inorganic pigments; organic pigments; and organic dyes. The molds may also be constructed to achieve a finish on the concrete that mimics the appearance of stone, brick, or decorative mosaic tile. Different coatings are also available for concrete, for example, see U.S. Patent Ser. No. 12/069,734, filed on Feb. 12, 2008, the disclosures of which are herein incorporated by reference. 
         [0050]    The blocks may also be formed using air entrained concrete. Air entrained concrete is advantageous for a number of reasons. It results in concrete products having a reduced density. The resulting products also have improved thermal properties. The resulting air entrained blocks provide greater insulation so that the block may be easily handled even when one side had been recently exposed to high heat. The air entrained concrete blocks also have greater resistance to degradation from freezing and thawing of trapped moisture which typically causes expansion and cracking of concrete. 
         [0051]    The courses may be assembled to create a stable structure without the use of either mortar, or pins or fasteners of any kind, and unlike prior inventions, they are assembled by using only one joint configuration, which can be incorporated into the elastomeric mold. All of the blocks types, shown in  FIGS. 8A through 8K , including a block referred to herein as slab member  30 , may be formed with a plurality of notches  15  ( FIG. 2A ), which are utilized to interlock the blocks, and allow them to dovetail with adjacent blocks. The slab member  30  may generally have a flat upper surface  31  and a flat lower surface  32  which is parallel to upper surface  31 . The slab, other than flat upper surface  31  and flat lower surface  32 , may take any shape, including, but not limited to an oval, a polygon, or a complex curved surface. One form which slab member  30  may take is that of a rectangular block, whereby the slab member  30 , in addition to the upper surface  31  and lower surface  32 , may have an inside surface  33  and an outside surface  34 , which are generally parallel to each other and are each orthogonal to the upper and lower surfaces, and front end surface  35  and rear end surface  36 , which are generally parallel to each other and each of which is orthogonal to the inside and outside surfaces,  33  and  34 . Although this illustration will proceed with the rectangular block slab now described, it can also now be clearly seen that the inside surface  33 , outside surface  34 , front end surface  35 , and rear end surface  36  could alternatively be curved, and also could smoothly transition into each other and thus create one continuous surface which could, for example, form an elongated race track shape. 
         [0052]    As previously stated, slab member  30  may incorporate a plurality of notches. The notches may comprise many different arrangments, including, but not limited to: a rectangular shaped notch  15 ; a V-shaped notch with matching V-shaped protrusion and indentation (see  FIG. 9B ); a cylindrically-shaped notch with a cylindrically-shaped male protrusion and a matching cylindrically-shaped indentation; a hemispherical shaped notch with a protruding male hemisphere and and indented female hemisphere; a conically shaped notch with protruding male conical shape and a female conical indentation; and a complex curve-shaped notch. In a preferred embodiment, notch  15  (see  FIG. 2A ), may have a first notch side wall  16 , a second notch side wall  17 , and a notch bearing face  18 , where the first notch side wall  16  and the second notch side wall  17  are generally parallel to each other, and orthogonal to the notch bearing face  18 . 
         [0053]    A preferred embodiment of rectangular slab member  30  may are four notches  15 : a first top notch  37  and a second top notch  38 , both formed on upper surface  31 ; and a first bottom notch  39  and a second bottom notch  40 , both formed on lower surface  32 . The first top notch  37  on the upper surface  31  is located directly opposite the first bottom notch  39  on the lower surface  32 , and the second top notch  38  on the upper surface  31  is located directly opposite the second bottom notch  40  on the lower surface  32 , so as to form corresponding pairs of notches with one pair on each end of the slab member  30 . One pair of notches  15  may be located near the front end surface  35 , and the other corresponding pair of notches  15  may be located near the rear end surface  36 . In the preferred embodiment, the corresponding pairs of notches are each located roughly the same distance away from end surfaces  35  and  36 . 
         [0054]    To construct a first course—the bottom course  20  for fire pit  13 , a first pair of slab members  30  are positioned parallel to each other with the lower surface  32  of each pair flush with the ground, and spaced apart such that the distance between respective inside surfaces  33  or respective outside surfaces  34  is equal to the distance between first top notch  37  and second top notch  38 . The reference to ground herein includes, but is not limited to, an assembly surface comprising soild, grass, a concrete slab, a brick or stone pedestal, etc. A second pair of slab members  30  are positioned parallel to each other and spaced apart so as to allow each of the first and second bottom notches  39  and  40  to dovetail with the first and second top notches  37  and  38  of the first pair of slab members. Successive courses  21  may then be added, with each such course having a primary pair of of slab members  30 , and a secondary pair of slab members  30 , which are assembled in like fashion to the first and second pairs of slab members  30 , by dovetailing to the course immediately below, which may at first be the bottom course  20 , and thereafter may be one of the successive courses  21 . 
         [0055]    Although a successive course  21  of slab members for fire pit  13 , as with bottom course  41 , will consist of four slab members  30 , the fire pit height can also be adjusted by utilizing only one-half of a course, which may be accomplished through the addition of only two additional slab members  30 . As illustrated in  FIG. 3 , the fire pit  13  was assembled using ten slab members, and has two full courses and one half of a course. 
         [0056]    The manufacturer will have the option of producing, and the user the option of purchasing, one additional block to tailor the fire pit  13 , whereby that block—a plain slab member  80 , does not have first and second top notches  37  and  38 , but is otherwise formed exactly like slab member  30  having first bottom notch  39  and second bottom notch  40 . Use of a pair of plain slab members  80  to add a half of a course permits the fire pit to have a smooth top edge as shown by fire pit  12  in  figure 4 . Although the dovetail interlocking of the first pair of slab members  30  of the bottom course  20  with the second pair of slab members will result in the second pair of slab members being raised slightly off of the ground, for a fire pit, this would be advantageous in permitting a flow of air to maintain a robust fire, while still serving to contain the fire. The first and second bottom notches,  39  and  40 , comprising the first pair of slab members of bottom course  20  (see  FIG. 3 ) could similarly serve to permit air flow. Alternatively, instead of using two of slab members  30  for the first pair of members of the bottom course  20 , two plain slab members  80  could be used instead to provide a straight finish as shown in  FIG. 4 . However, it is worthy of emphasis that a fire pit may be built, and quite easily and without reference to a set of instructions, utilizing multiple copies of slab member  30 , and it furthermore could be easily and quickly modified for an increase or reduction in height by adding or removing slab members  30 . 
         [0057]    The fire pit  13  may also be converted for use as a barbeque grill by adding top grill  5  ( FIG. 5 ), which may, in a preferred embodiment be constructed of angle iron  6  and a grilling surface  7 . The grill surface may simply be a traditional metal grate, and be formed of copper; carbon steel; cast iron; stainless steel; bronze; brass; aluminum; high temperature glass; or opaque glazed high impact ceramic. The top grill  5  could be placed directly upon opposite slab members, or alternatively, the slab members could incorporate a plurality of orifices, into which may be inserted dowel pins  9  or a rod, which may protrude into the interior of the fire pit or grill ( FIG. 2A ), and upon which the top grill  5  may rest. 
         [0058]    Additional dowel pins  9  could be inserted into another course so as to support a bottom grill  8 . The bottom grill  8  could be formed similar to top grill  5 , and also could alternatively incorporate a gas burner to supply heat for cooking, instead of using a fire. 
         [0059]    To achieve a barbeque grill which is better adapted for cooking more comfortably and for servicing, a configuration may be easily created whereby the lower front portion of the grill may have a front opening  19  as seen in  FIG. 2 . The front opening  19  may be created by adding one or more additional courses  22  below the bottom course  20 , which in practical terms would dictate that the additional courses  22  were actually the first courses to be assembled with initial placement on the ground. The additional courses  22  may be formed by utilizing a first pair of slab members  30  (or pair of plain slab members  20 ) and then a different second pair being a set of lateral slab members, which may be comprised of one slab member  30  and two spacer slab members  50 . The spacer slab member  50  shown in  FIG. 8C  may be constructed the same as slab member  30 , except that it is significantly shorter and does not have the second top notch  38  and the second bottom notch  40 . Assembly of the additional courses may be achieved in similar fashion to the bottom course  20  and successive courses  21 , but where the the two spacer slabs  50  replace one of the the two slab members  30  of the second or secondary pairs in a course. 
         [0060]    Another feature which may be incorporated into an embodiment of the present invention is a backsplash as shown for barbeque grill  11 , in  FIG. 2 . A plain slab member  80  may be utilized on the top course  23 , where the top course is the last of the successive courses  21  added, and where the plain slab member  80  is located opposite to the front opening  19 . 
         [0061]    A further embodiment of the present invention may include a fume hood  3 , one possible embodiment having a fume hood  3  is shown in  FIG. 7 . The fume hood  3  may rest directly on top of the top grill grate  5 , or could be formed to rest on the top course  23 . The fume hood  3  may also be mechanically attached to slab members using, though not limited to, dowel pins, masonry screws, or anchors. The fume hood  3  may be constructed of copper, brass, ferrous alloy, bronze, aluminum, or of flame proof composite materials, including, but not limited to, phenolic resin, fiberglass, or carbon fiber reinforced epoxy. The fume hood  3  may also have insulated side handles  4  which are integrally formed or mechanically attached to the fume hood  3 . 
         [0062]    Another embodiment that incorporates a fume hood is shown in  FIG. 1 , and may comprise a hood constructed of blocks. In a preferred embodiment, the barbeque grill  10  could be completed through additional assembly of slabs onto the barbeque grill  11  in  FIG. 2 , by initially removing the back splash that was created through use of plain slab member  20 . The top one-half course of the barbeque grill of  FIG. 2  was shown, merely to be illustrative of the versatility of the invention, by having one splash slab member  70  and one slab member  30 . The most economical and simplest approach would be to use two slab members  30 , and disregard the unused second top notch  38 , however, a splash slab member  70  could be formed the same as a slab member  30 , but without a second top notch  38 . 
         [0063]    The barbeque grill  10  would require two transition slab members  60 , which are shown in  FIG. 2A . With the plain slab member  80  back splash having been removed, assembly of the block fume hood may proceed. The assembly process is comparable to that of the additional courses  22  for the grill with the front opening. One or more open hood courses  25  are first added. These open hood courses  25  are comprised of a pair of short slab members  90  ( FIG. 8G ) and a set of the lateral slab members, which, as for the additional courses  22 , are comprised of one slab member  30  and two spacer slab members  50 . One or more closed hood courses  26  may be used to create a more vertical fume hood, where the closed hood courses  26  are comprised of a pair of short slab members  90  and a pair of slab members  30 . A tapered look to the fume hood may be achieved by using telescoping hood courses  27 , which are comprised of a pair of short slab members  90  and a pair of variable length slab members. The variable length slab members are formed the same as the slab member  30 , except that the length is shorter, and the first and second top notches,  37  and  38 , are positioned father away from the front end surface  35  and rear end surface  36 , than the first and second bottom notches,  39  and  40 . In a preferred embodiment, three different variable length slab members were utilized, a standard variable length slab member  100 , a shorter variable length slab member  110 , and a shortest variable length slab member  120 . For an aesthetically appealing finish, a pair of short plain slab members  130  may be added to the last telescoping hood courses  27 . 
         [0064]    The versatility of the block members of the present invention additionally lend the user to custom creating fire pit or barbeque grill accessories, trays or tables, or even integral seats. For example, a table may be formed by utilizing the barbeque grill  11  of  FIG. 2  by constructing, adjacent to the grill, a column of blocks  30 , as seen in  FIG. 2A , but also having spacer slabs  50  for a stable structure. The top course may have a table slab  150  similar to transition slab  60 , but with a series of regularly spaced notches that may support a series of plain slab members  80  that create a surface comparable to a redwood picknick table. The grill  22  may have mechanical supports for the series of plain slab members  80 , but in a preferred embodiment, one of the slab members  30  of the top course  23  would have be replaced with a table slab member  150 .