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RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. provisional patent application Ser. No. 61/072,789 for MODULAR FLOOR SYSTEM filed Apr. 3, 2008, the entire disclosure of which is fully incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    A modular floor system is a semi-permanent surface assembled using a plurality of smaller, usually identical floor panels to provide a stable, uniform and durable surface. These floor systems are typically installed over rigid surfaces such as concrete or semi-rigid surfaces such as grass or sand to provide a temporary platform for a variety of uses. Care must be taken in that some conventional edge joined modular floor systems installed over semi-rigid surfaces will tend to “unlock” from the adjacent panels during use creating a hazard, especially for foot traffic. Other uses include covering and protecting surfaces from non-intended uses such as covering over a polished wooden basketball floor to prevent damage from hard-soled shoes or covering an ice rink so that it can be used for other functions. 
         [0003]    Floor panels are typically square in shape although other shapes have been used such as rectangular or polygonal. The panels are formed from a variety of materials including wood, plastic or metal and usually include complementary interlocking features around the periphery so as join with adjacent panels to form a unified structure. The key aspects of modular floor systems are that they can be quickly and easily assembled and disassembled and therefore easily transported and stored. 
       SUMMARY 
       [0004]    The present invention relates to a modular floor system employing shared loading between adjacent panels. The modular floor system is comprised of a plurality of lower panels with each panel having interlocking features and a plurality of upper panels with each panel having interlocking features. The lower panels are arranged in a pattern adjacent to each other. The upper panels are similarly arranged in a pattern adjacent to each other and positioned above the lower panels. The pattern of upper panels is arranged such that each upper panel interlocking features engages with the complementary interlocking features of a plurality of lower panels. The resulting unified structure forms a substantially planar surface. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]      FIG. 1  is a perspective view of a modular floor system according to one embodiment of the present invention with one corner area partially assembled to show construction; 
           [0006]      FIG. 2  is an enlarged perspective view of the partially assembled corner area of  FIG. 1 ; 
           [0007]      FIG. 3A  is a cross-sectional view of a modular floor system panel according to one embodiment of the present invention; 
           [0008]      FIG. 3B  is an enlarged portion of  FIG. 3A  illustrating several interlocking features; 
           [0009]      FIG. 3C  is an enlarged portion of  FIG. 3A  illustrating an interlocking feature; 
           [0010]      FIG. 4A  is a cross-sectional view of an alternate modular floor system panel according to one embodiment of the present invention; 
           [0011]      FIG. 4B  is a cross-sectional view of an alternate modular floor system panel according to one embodiment of the present invention; 
           [0012]      FIG. 4C  is a cross-sectional view of an alternate modular floor system panel according to one embodiment of the present invention; 
           [0013]      FIG. 5  is a perspective view of a modular floor system according to one embodiment of the present invention depicting assembly of the modular floor system panels; 
           [0014]      FIG. 6  is a cross-sectional view of an assembled modular floor system according to one embodiment of the present invention taken along section  6 - 6  in  FIG. 2 ; 
           [0015]      FIG. 7  is an enlarged portion of  FIG. 6  illustrating the interlocking features. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    A modular floor system  10  as illustrated in  FIGS. 1-2  includes interlocking upper panels  12 , lower panels  14  and edge covers  16 . According to one embodiment of the present invention, upper panels  12  and lower panels  14  are preferably the same so as to facilitate ease of manufacture and resulting cost savings. As will be described in more detail later, alternate embodiments of the present invention could include upper and lower panels that are constructed differently to tailor the floor system for a specific uses. 
         [0017]    In describing one embodiment of the present invention, the upper panels  12  and lower panels  14  will be assumed to be identical such that the description from hereafter, unless otherwise described, will be the same for both panels. Panel  12  is typically constructed of plastic, but other materials are possible such as aluminum. Panel  12  is made by first extruding plastic such as polypropylene, polyvinylchloride (PVC) or any other suitable plastic material into a typical cross-sectional shape as shown in  FIG. 3A . The plastic extrusion process is especially well-suited for producing panels  12  since it provides a cost efficient means of producing a consistent cross-section and allows the variability of making different lengths. Cross-sectional width W and thickness T can be designed to any practical size, but it is usually dictated by a combination of manufacturing and application considerations. Typical panel  12  widths are 8, 12 and 16 inches although other widths are easily feasible. Likewise, a typical panel  12  thickness is approximately 0.5 inch, although it can be made larger such as 1 inch, 2 inches or greater depending on the application. 
         [0018]    Individual panels  12  are formed by cutting the extruded plastic shape to any desired length, but preferably even lengths such as 2, 4 or 8 feet. The panel  12  length can be tailored to a specific application which may involve a variety of factors such as shipping and handling considerations, and ease of assembly or disassembly. For instance, a typical homeowner application may require shorter length panels than those used for commercial applications. 
         [0019]      FIG. 3A  illustrates a typical cross-sectional shape of extruded panel  12 . Panel  12  is extruded as a unified structure and is comprised of outer surface  20 , inner surface  22 , main latch  24 , side latches  26 , ribs  28  and locking ribs  30  and is essentially symmetrical about a vertical centerline through main latch  24 . Since panel  12  is formed by the extrusion process, these features are consistent throughout the length of the panel. The outer surface  20  is generally planar but can include surface treatments or features to enhance aesthetics or functional characteristics such as a decorative wood grain lamination for appearance and scratch resistance, grooves or texture for traction purposes, or perforations for drainage or ventilation. The inner surface  22  is generally planar and essentially parallel to outer surface  20 . Main latch  24  is located substantially around the midpoint of the cross-sectional shape, but in an alternate embodiment can be offset in either direction depending on the panel overlap required for a particular application. Side latches  26  are located along the longitudinal sides of the extrusion and are designed to mate with main latch  24 . Ribs  28  project substantially perpendicular from inner surface  22  and are located symmetrically to either side of main latch  24 . 
         [0020]    Referring to  FIG. 3B , main latch  24  is comprised of a central portion  32  which projects substantially perpendicular from inner surface  22 , two locking flanges  34 , and two alignment flanges  36  that form recess  38 . Locking flanges  34  project laterally outward from central portion  32  at approximately the midpoint while alignment flanges  36  project laterally outward and then downward to form recess  38 . 
         [0021]    Referring to  FIG. 3C , side latches  26  are located along the longitudinal sides of the extrusion and include body portion  40 , hook  42  and side flange  44 . Body portion  40  extends substantially perpendicular from inner surface  22  and is designed to flex laterally during assembly or disassembly of the floor system  10 . Hook  42  is located at the end of body portion  40  and projects laterally outward. The angles of the two sloping surfaces on hook  42  are designed to permit easy assembly and positive locking between panels  12  but yet allow disassembly when required. 
         [0022]      FIGS. 4A-4B  illustrate alternate cross-sectional shapes of panel  12  that are similar to that shown in  FIG. 3A  but differ in the design of main latch  24  and corresponding side latches  26 .  FIG. 4C  is yet another alternate cross-sectional shape of panel  12  with a different design of main latch  24  and side latches  26  but illustrating a possible asymmetrical cross-sectional shape. 
         [0023]    Referring to  FIGS. 1-2 , the assembly of floor system  10  will be described using upper panels  12  and lower panels  14  for clarity of orientation, although it is still assumed that both panels  12  and  14  are identical in construction and configuration. Assembly begins by first arranging multiple lower panels  14  with outer surface  20  in contact with the surface to be covered. Lower panels  14  adjacent in the longitudinal direction are positioned with their ends touching and their extruded features aligned longitudinally. Lower panels  14  adjacent in the latitudinal direction are positioned such that their ends are offset from each other in a longitudinal direction so as to create a longitudinal overlap when upper panels  12  are assembled. The longitudinal offset of adjacent lower panels  14  can be as little as two inches or as much as half the longitudinal length depending on the specific application. The longitudinal offset pattern can be a simple staggering of every other latitudinal lower panel  14  or can follow a staggering pattern spread over multiple adjacent panels. For instance, the first adjacent lower panel  14  can be offset by four inches; the next lower panel  14  is offset by an additional four inches, and so on until the pattern repeats. Once the entire field of lower panels  14  is installed over the surface to be covered, the lower panels  14  can be easily trimmed with an appropriate cutting tool to create a straight edge on each longitudinal end of floor system  10  or left as staggered edge created by the longitudinal panel offset. 
         [0024]      FIG. 5  illustrates a typical orientation and assembly of upper panels  12  onto lower panels  14 . Upper panels  12  and lower panel  14  with the cross-sectional shape shown in  FIG. 3A  are shown in a partially assembled state with one upper panel  12  assembled with a lower panel  14  and another upper panel  12  positioned for assembly. Upper panels  12  are positioned and installed on lower panels  14  such that they are offset latitudinally from lower panel  14  by half the width of each panel. Like the arrangement of lower panels  14  previously described and as shown in  FIGS. 1-2 , upper panels  12  are offset longitudinally from adjacent upper panels  12  so as to overlap and directly interlock with four lower panels  14 . Additionally, each panel  12  will indirectly interlock with up to six adjacent panels  12  and  14  through the joints created by hooks  42  and main latches  24 . This results in each joint being supported by up to ten panels  12  and  14 . The combination of longitudinal and latitudinal overlap creates a unified structure that eliminates the need for a rigid or semi-rigid support surface. Also, recess  38  is specifically located as near as possible to the surface of panel  12  to limit joint flexure when loaded in tension so as to add further rigidity to the structure. In operation, any external load applied to the floor surface, whether above or below, is therefore shared by multiple panels resulting in a much stronger and stiffer floor. 
         [0025]    Once upper panel  12  is positioned over lower panels  14  with the desired longitudinal overlap and with side latches  26  aligned for engagement with the corresponding main latches  24  of the lower panels  14 , a downward force F is applied to upper panel  12  along one longitudinal edge above the side latch  26  so as to force it into engagement with the corresponding main latch  24 . The downward force can be generated in practice by merely stepping down on the upper panel  12  with a foot or through the use of a tool such as a rubber mallet or weighted roller. As upper panel  12  travels downward, the side flange  44  pilots into recess  38  in the main latch  24 , and hook  42  of side latch  26  contacts the locking flange  34  of the main latch  24  and is deflected laterally away from locking flange  34 . Referring to  FIG. 7 , as upper panel  12  completes its engagement with lower panel  14 , side flange  44  further engages and aligns itself in recess  38 , and hook  42  moves past locking flange  34  and then is able to return back to its original shape and thereby engage locking flange  34 . Once the one longitudinal edge of upper panel  12  is secured, the assembly procedure is repeated with the main latch  24  of upper panel  12  as shown in  FIG. 5  and then again for the remaining longitudinal edge of upper panel  12 . It is also conceivable that both longitudinal edges and main latch  24  of upper panel  12  can be simultaneously joined to lower panels  14  with an appropriate tool having sufficient width to span beyond the width W of upper panel  12 . For instance, a heavy roller type of tool such as a lawn roller could be employed. 
         [0026]    Referring to  FIGS. 5-7 , as upper panel  12  is mated with lower panels  14 , ribs  28  automatically align with locking ribs  30 . The interlock between ribs  28  and locking ribs  30  prohibits ribs  28  from deflecting laterally and therefore provides rigid vertical structural support to outer surface  20 . 
         [0027]    Referring to  FIGS. 1 ,  2  and  6 , edge covers  16  provide a functional height transition as well as a decorative edge treatment and are installed over the edge of panels  12  and  14  around the perimeter of floor system  10 . Edge covers  16  are extruded plastic similar to panels  12  and  14 , and are cut to a practical length such as 8 or 16 feet. 
         [0028]    Floor systems  10  are semi-permanent in nature and are designed to be easily disassembled. Disassembly of the exemplary floor system  10  is as simple as reversing the assembly operation. After removing edge covers  16  and then starting at one corner of floor system  10 , disassembly is initiated by lifting up along one longitudinal edge of the end of one upper panel  12  to start disengaging hook  42  from main latch  24  in lower panel  14 . Continuing with the lifting motion in a slight peeling manner will then further progressively disengage hook  42  along the longitudinal edge and simultaneously start disengaging main latch  24  in upper panel  12  from hooks  42  in lower panels  14 . As the disassembly motion progresses, the opposite longitudinal edge of upper panel  12  will then start to disengage from lower panels  14  until the entire upper panel  12  is free The remaining upper panels  12  of floor system  10  are disassembled in the same manner. The disassembly process can also be described as an unsnapping or unzipping process. The disassembly process can also be made even easier by using a specially designed tool to accomplish the disengagement of hooks  42  with main latches  24 . For instance, a wedge shaped unzipping tool can be inserted between hooks  42  in upper panels  12  and main latch  24  of lower panel  14  and then pushed or pulled along the longitudinal edge to quickly and continuously unlock an entire length of panels  12 . Then the disassembly of main latch  24  in each upper panel  12  is more easily accomplished by the aforementioned lifting motion. 
         [0029]    Individual panels  12  and  14  are designed for manufacturing considerations, easy handling and installation. While it was previously described that floor system  10  can be disassembled into individual pieces, it is often advantageous to disassemble floor system  10  into large sections. For instance, if floor system  10  is assembled from panels  12  and  14  that are 12 inches wide by 4 feet long, it could be readily disassembled into easily manageable sections measuring approximately 48 inches wide by 8 feet long, or in other words, four panels wide by two panels long. Panels of this size are similar to many sheet building materials and therefore are easily stored. Obviously, many other configurations are possible and can easily be determined and managed by the user depending on the needs of a particular installation. 
         [0030]    In alternate embodiments of the invention, panels  12  and  14  can be of different sizes depending on the application. For instance, upper panel  12  can be made twice as wide as lower panel  14  so that there are fewer visible joints on the upper surface of floor system  10  thereby possibly enhancing the aesthetic appearance. This unequal panel size can also increase the structural rigidity of floor system  10 . In another alternate embodiment, upper panels  12  with, for instance, two or three different widths, can be installed in an alternating pattern to provide an aesthetically pleasing appearance. 
         [0031]    While the present invention has been illustrated by the description of embodiments thereof, and while the embodiments have been described in considerable detail, it is not the intention of the specification to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. For example, individual components can be combined, assemblies can be divided into separate components or components can be rearranged without affecting the operation. Therefore, the invention, in its broader aspects, is not limited to the specific details, the representative apparatus, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of the applicant&#39;s general inventive concept.

Summary:
A modular floor system employing shared loading between adjacent panels. The modular floor system is comprised of a plurality of lower panels with each panel having interlocking features and a plurality of upper panels with each panel having interlocking features. The lower panels are arranged in a pattern adjacent to each other. The upper panels are similarly arranged in a pattern adjacent to each other and positioned above the lower panels. The pattern of upper panels is arranged such that each upper panel interlocking features engages with the complementary interlocking features of a plurality of lower panels. The resulting unified structure forms a substantially planar surface.