1.  Field of the Invention
The invention relates to floor tiles, and is directed in particular to a type of flexible interlocking floor tiles made from rubber or the like.  More particularly, the invention relates to interlocking floor tiles which can be easily manufactured and installed without the need of a professional installer, and without requiring the use of glue or other adhesive in the installation of the floor tiles. 
2.  Description of the Prior Art
Various types of commercial flooring are known in the art.  Places which utilize commercial flooring are usually high traffic areas and include office buildings, hospitals, recreation centers, hotels, apartment buildings, etc.  These high traffic areas often require durable yet inexpensive flooring with aesthetic appeal as well.  Traditional wood flooring is expensive and difficult to maintain and is not ideal for commercial use.  Ceramic and stone flooring, laminate tiles, vinyl tiles/planks and LVT (luxury vinyl tiles) are all alternatives to wood flooring but are also expensive—these types of flooring and tiles are also rigid, not flexible or cut resistant, and are not as slip resistant as floors containing rubber.  Carpet is not usually desired in high traffic areas since it will wear very quickly, is difficult to clean and must be replaced often, and may impede the travel of vehicles thereacross.  Even if the above types of flooring are chosen for commercial use, they require significant time and effort to properly install.  If a new building is being constructed, construction may be delayed based on the time it takes for installation of any of the above flooring.  Furthermore, removing and replacing any of the above floor types is also expensive and time consuming, which may cause delays in actual operation of the business inside the building.  Some such removal and replacement is at times done at night or on weekends so as not to obstruct traffic where such activities are being done.  Should the original flooring contain asbestos, removal becomes even more costly due to the procedures necessary for such removal and disposal
Based on the above shortcomings of the various flooring mentioned, cheaper yet durable flooring made from rubber, vinyl and the like has been used for commercial settings.  Such flooring usually comprises individual molded tiles, panels, boards etc.  which interlock together and are placed over a subfloor.  Various types of interlocking mechanisms are known in the art.  For example, Johnsonite Inc. of Chagrin Falls, Ohio has manufactured an interlock tile under the name UNDERLOCK®.  The UNDERLOCK® tile features an interlocking mechanism in the form of a tongue and groove connection on the underside of the tile which fit together like a puzzle without the need for an adhesive either between the respective tiles, or between the tiles and the floor or subfloor.  These UNDERLOCK® tiles are easy to install and uninstall and can be done without a professional installer. 
One drawback with most molded products is the presence of flashing that is left behind on the product after the molding process.  Flashing is excess material which exists in a thin layer exceeding normal part geometry of the product.  The flashing extends from a molded product, and must usually be removed.  Flashing is typically caused by leakage of the molding material between the two surfaces of a die or mold that actually leaks out of the mold.  The leakage is often due to excess material in the mold which exceeds normal part geometry.  With respect to interlocking flooring assemblies, flashing must be removed in order to ensure a precise interlocking fit between the tiles.  Any excessive flashing which is not removed from the interlocking tiles may compromise the integrity of the mating of the tiles, which could lead to uneven flooring, curling and peaking etc.,  and also may add difficulty to the installation of such tiles.  The flashing is typically removed during the production process with a utility knife or other tool to cut away and remove the excessive flashing.  Since removal of the flashing is another time consuming and costly step, a quick and easy method for such removal is desired.  Flash removal is particularly time consuming for tiles having intersecting edges which are not straight.  Thus, flash removal must occur along curved edges or edges which are not straight, requiring additional time and expense for this tedious process.  Flash removal is thus a serious impediment to molded floor tile installers. 
Additionally, some tiles feature a studded partial backing to keep the tiles raised above the subfloor while providing air space between the studs.  Such studs allow less contact with the subfloor in the event contaminants and liquids are present.  However, the studs extend only over the tongue and groove configuration or interlocking mechanism and do not cover the entire bottom of this type of tile.  The tongue and groove configuration is often an important feature of this type of tile. 
U.S. Publication No.  2005/0183370 to Cripps discloses a floor tile with interlocking edge elements that enable juxtaposed tiles to be assembled by a vertical snap or press-in assembly method to secure tiles together.  A first and second pair of contiguous lateral extension walls of the tile are arranged to meet at a square corner of approximately ninety degrees and lie at opposite edges of the tile from the first two lateral extension walls.  The second lateral extension walls meet at a common corner that is diagonally opposite from another corner.  The floor tile has two channels as a result of first and second lateral extension walls which form part of the interlocking mechanism.  The sidewalls forming the channels include an undercut as part of the interlocking mechanism.  The tile does not include a downwardly extending member at the corner of the tile for additional support at the corner of tile.  The floor tile is made from one material rather than a dual construction made of two materials.  Furthermore, the floor tile of Cripps is a two piece construction which further includes a separate, compressible seal. 
U.S. Publication No.  2007/0011980 to Stegner et al.  discloses a unitary interlocking floor tile with interlocks located on adjacent sides of the tile having a gap located at a mid point of the interlocks along each side of the tile, creating a discontinuous interlocking structure on the sides of the tile.  The interlocking structure does not fully extend to the corner of the tile.  Stegner et al.  does not teach a continuous interlocking structure on adjacent sides of a tile extending to the corner of the tile.  The discontinuous interlocking structure of Stegner et al.  leads to multiple joints when interconnecting the tiles, which can result in a loose fit amongst the tiles, creating both functional and aesthetic problems.  If the discontinuous interlocking structure is not a completely straight line between the gap, realignment problems can occur when fitting multiple tiles together, especially if the tiles are staggered and not side by side.  The discontinuous locking structure also results in an excessive amount of time required to remove the flashing from the interlocking structure as well as requiring additional time for the installer to remove such flashing, since the direction for the utility knife to move must be interrupted on different sides of the tile.  This is due to the gap located at a mid-point of the interlocks along each side of the tile, wherefore the installer cannot remove the flashing in a single motion using a utility knife.  The interlocking floor tile is made of one material. 
U.S. Publication No.  2003/0093964 to Bushey et al.  discloses a floor grid system including a number of interconnectable tiles made from one material.  The tiles are interconnected with one another through the use of locking assemblies extending between the tiles.  The locking assembly uses half dove tails as the interlocking configuration.  The upper face of the tile includes two locking elements on two adjacent sides of the upper face of the tile.  The bottom face of the tile includes two locking elements on the opposite adjacent sides of the bottom face of the tile.  Each locking element includes a base projecting outwardly from the tile and an upwardly extending vertical member having an inner surface spaced from a corresponding side of the tile so as to define a wall receiving channel therebetween.  The locking elements on adjacent sides of the tile extend beyond the corner of the tile, with a vertical protrusion located that the intersection of the locking elements.  Bushey et al.  does not include a downwardly extending member at the corner of the tile.  Furthermore, the locking elements have numerous edges in difficult directions causing a large amount of time for flash removal. 
U.S. Publication No.  2010/0319282 to Ruland discloses a vinyl floor panel prepared from a blend of a polymer and cork granules.  The tiles may are interconnected with one another through the use of a locking system between the tiles.  Similar to Bushey et al.  discussed above, the locking elements on adjacent sides of the tile extend beyond the corner of the tile, with a vertical protrusion located that the intersection of the locking elements.  Ruland does not include a downwardly extending member at the corner of the tile. 
Accordingly, there is a need for a tile with an interlocking mechanism which is partly spaced from the floor or subfloor and possible contaminants on the floor or subfloor when installed.  Such a tile should be easy to manufacture and allow for some purposeful misalignment of seams of the tile to allow for different layout designs and for multiple size tiles to be fitted together, which does not detract from the aesthetics of the tiles when laid or from their functionality.  The tile should be inexpensive yet fulfill its purpose of being an easy to install, durable having a long life, and be able to withstand its intended loads.  There is also a need for a tile which reduces the amount of flashing to be removed, and which is easier to install and re-install than existing tiles, saving installation time.  Desirably, such a tile would allow for a continuous connection along all of the sides of the tile and include adequate support at the corner of the tile.  The latter feature would prevent depression, sinking, bending or buckling of the corners of overlapping, installed tile portions, as when the heel of a high heel shoe is pressed thereon.  The desired tile would have a single interlocking structure or groove to keep the entire tile joint tight with other tile joints, instead of interrupted interlocking structure which could lead to functional and aesthetic flaws in the entire floor.  The single continuous interlocking structure would allow for a one-step easy removal of any excess material or flashing from the tile after the molding process.  The tile would desirably include a random or continuous uniform distribution of shallow studs on the entire bottom of the tile to allow for less contact with the underfloor should it contain contaminants.  Construction with studs also makes the tile lighter and easier to install, lift up in the event one has to inspect the floor below it or to replace a tile.  Being of less weight is also more environmentally responsible, allowing less fossil fuel to be used for shipping the tile to its final destination.  Most desirably, such a unit maintains a strong, structurally sound mounting of the tile on the floor which allows for easy installation.  Time saving is particularly important in multiple room facilities where flooring needs to be installed quickly and cost efficiently such as for apartment buildings, hospitals, hotels and the like, where new building construction and renovations are common.  The tiles can be removed and reused or repurposed in other areas, avoiding costly landfill charges, making them yet more environmentally friendly.  Thus, the problem to be solved by the present invention is to provide a tile with the above characteristics. 
Many floor tiles are made from expensively compounded vinyl, linoleum or rubber containing no inexpensive recycled materials.  This can be costly, particularly for commercial buildings with extensive floor space to be covered with the tile.  It would be advantageous to employ less expensive tiles with inexpensive recycled vinyl, rubber or the like on part of the underside of the tile where it is not visible after it is laid, yet serves its intended purpose and has all of the necessary structural features.