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CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    Not applicable. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not applicable. 
       BACKGROUND OF THE INVENTION 
       [0003]    1. Field of the Invention 
         [0004]    The present invention relates to exterior hardscaping. More specifically, the present invention relates to a paving stone for use in roadways, sidewalks, and other hardscaped surfaces to construct permeable surfaces. 
         [0005]    2. Description of the Related Art 
         [0006]    An interlocking paving block, or paver, is a pre-cast piece of material—typically concrete or clay—that is commonly used in exterior hardscaping applications, such as roads, walkways, patios, pool decks, and driveways. Such pavers are installed over a compacted stone sub-base and a leveling bed of sand. 
         [0007]    Instead of connecting the pavers by pouring grout between the joints, as one would do with tiles, sand particles are spread over the pavers and tamped down. The sand stabilizes the interlocking pavers, yet allows for some flexibility. Typical paver hardscapes will absorb the stresses caused by freezes, thaws, and slight ground erosion by shifting each paver slightly. This minimizes cracking or buckling often associated with concrete surfaces. 
         [0008]    Interlocking pavers can also be used to construct permeable surfaces. These pavers are configured to maintain open joints or gaps between adjacent pavers. The joints or gaps are filled with a permeable material that allows stormwater to infiltrate down through the surface. The open joints traditionally compromise 5 to 15% of pavement surface and the joints are limited in width to ten-millimeter for compliance with the requirements of the Americans with Disabilities Act. Permeable pavement surfaces are a method to reduce stormwater runoff and water pollution, along with other benefits. 
         [0009]    Many modern permeable pavers include spacers, but such spacers do not allow the paver to be arranged in multiple configurations while still providing interlocking functionality from the spacers. For example, U.S. Pat. No. 6,015,243 discloses a paving stone with support attachments arranged on the lateral surfaces. The paving stone includes two attachments on each lateral surface. As shown in  FIG. 7  of the &#39;243 patent, movement in one direction parallel to the lateral surface will be resisted by one of the attachments on a lateral surface but not the other attachment, which could cause adjacent paving stones to rotate with respect to each other at the point of contact depending on the strength and direction of the applied force. In other words, interlocking functionality is not provided by all of the attachments on the relevant side in both directions. 
         [0010]    U.S. Pat. No. 5,902,069 teaches a paver with identical spacing elements formed around the lateral surfaces of the paver body. Each spacing element is capable of being engaged by an identical but oppositely orientated spacing element or an adjacent paver. One drawback to this technique, however, is that, because each spacing element is identical, the width of the space between the bodies of adjacent stones must be relatively large because each spacer must be wide and deep enough to include a trough and a tooth as well as handle the anticipated stresses that may be applied. It is also more difficult to manufacture the more intricate spacer design raising manufacturing costs. 
       BRIEF SUMMARY OF THE INVENTION 
       [0011]    The present invention provides an improved paving stone with interlocking and self-aligning spacers that, when installed with other similar paving stones, provides a strong structural interlock with a low profile and create relatively narrow joints between adjacent paving stones. The present invention can be aligned in multiple configurations. 
         [0012]    Specifically, the present invention comprises a paving stone in the shape of a rectangular solid with a top surface, a bottom surface, opposing long lateral surfaces, and opposing wide lateral surfaces. A single spacer extends from a first wide lateral surface and each of the long lateral surfaces and a spacer pair extends from the second wide lateral surface and each of the long lateral surfaces. The single spacers and spacer pairs are positioned on the lateral surfaces of the paving stone so that the single spacers interlock with the corresponding spacer pairs on a similar adjacent paving stone in multiple paving configurations. More specifically, the position of the single spacers and spacer pairs allow similar adjacent paving stones to be configured in a herringbone pattern, a runner bond pattern, and a basketweave pattern. 
         [0013]    Each spacer pair is comprised of two adjacent spacers defining a trough therebetween. Each of the single spacers and spacer pairs are sized and positioned such that a single spacer is positioned within the volume defined by the trough of a corresponding spacer pair of an adjacent paving stone when the paving stones are aligned in a desired pattern. The single spacers and spacer pairs are also sized and configured to ensure a maximum, predetermined gap width between adjacent paving stones. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0014]      FIG. 1  is an isometric view of the preferred embodiment present invention. 
           [0015]      FIG. 2  is a top view of the preferred embodiment of the present invention. 
           [0016]      FIG. 3  is a side view from line  3 - 3  of  FIG. 2  of the preferred embodiment of the present invention. 
           [0017]      FIG. 4  is a top view of a first alternative embodiment of the present invention. 
           [0018]      FIG. 5  is a top view of a second alternative embodiment of the present invention. 
           [0019]      FIG. 6  is a top view of an exemplar running bond pattern combining multiple paving stones of the present invention. 
           [0020]      FIG. 7  is a top view of an exemplar herringbone pattern combining multiple paving stones of the present invention. 
           [0021]      FIG. 8  is a top view of an exemplar basketweave pattern combining multiple paving stones of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0022]      FIGS. 1-3  show a preferred embodiment  20  of the present invention, which comprises a generally rectangular block body  22  having a generally rectangular traversable top surface  24  defined by opposing first and second long sides  26 ,  28  and first and second wide sides  30 ,  32 . The body  22  includes first and second long lateral surfaces  34 ,  36  orientated at a right angle relative to the top surface  24 , and first and second wide lateral surfaces  38 ,  40  that are adjacent to the first and second long sides  34 ,  36 . The first and second wide lateral surfaces  33 ,  40  are also oriented at a right angle relative to both the top surface  24  and the first and second long lateral surfaces. A chamfer surface  33  can be positioned between the top surface  24  and the first and second long lateral surfaces and first and second wide lateral surfaces. The body  22  is symmetrical about a first reference plane P 1  which is oriented perpendicular to the top surface  24  and that bisects the first and second wide sides  30 ,  32  of the top surface  24  with each of the first and second long lateral surfaces  34 ,  36  being a distance D 3  from the first reference plane P 1 . As used herein, a distance D between an element of the paving stone and lateral surface or between a reference plane and a lateral surface means the shortest perpendicular distance between the lateral surface and a parallel reference plane extending through the element or between the lateral surface and the reference plane. The body  24  is also symmetrical about a second reference plane P 2  that bisects the first and second long sides  34 ,  36  of the top surface  24  and is perpendicular to the first reference plane P 1 . 
         [0023]    A first spacer pair  46  extends from the first wide lateral surface  38  and comprises two adjacent convex spacers  48 . Each of the convex spacers has a crest  49  positioned a distance D 1  from the first wide lateral surface  38 . The two spacers  48  are joined to define a concave trough  50  between them. The trough  50  has a nadir  51  positioned a second distance D 2  from the first wide lateral surface  38  and a first trough curvature. As used herein, the nadir is the lowest point of the trough nearest the lateral surface from which the spacer pair extends. Preferably, the nadir  51  is centered on the first wide lateral surface  38  halfway between the first and second long lateral surfaces  34 ,  36  such that the first reference plane P 1  intersects the nadir  51 . 
         [0024]    Second and third spacer pairs  52 ,  54  extend from the first and second long lateral surfaces  34 ,  36 , respectively. Each of the second and third spacer pairs  52 ,  54  comprises two adjacent convex spacers  56 . Each of the adjacent convex spacers  56  has a crest  55  positioned a distance D 1  from the respective long lateral surfaces  34 ,  36  from which the spacers  56  extend. The adjacent convex spacers  56  of each spacer pair  52 ,  54  define second and third concave troughs  58 ,  59 , respectively, each having a nadir  51  positioned a second distance D 2  from the respective long lateral surfaces  34 ,  36  from which the spacer  56  extends. The second and third troughs  58 ,  59  of the second and third spacer pairs  52 ,  54  have a second trough curvature and a third trough curvature, respectively. A third reference plane P 3  is oriented perpendicular to the top surface  24  and the first reference plane P 1  and intersects each nadir  51  of the second and third spacer pairs  52 ,  54 . The third reference plane P 3  is positioned a distance D 3  from the second wide lateral surface  40 . 
         [0025]    A first single spacer  60  having a convex surface extends from the second wide lateral surface  40  of the body  22  and has a crest  61 . In the preferred embodiment, the crest  61  is positioned a distance D 1  from the second wide lateral surface and is centered on the second wide lateral surface halfway between first and second long lateral surfaces  24 ,  36  such that the first reference pane P 1  intersects the crest. 
         [0026]    Second and third single spacers  62 ,  64 , each having a convex surface, extend from the first and second long lateral surfaces  34 ,  36 , respectively. Each of said second and third single spacers  62 ,  64  have crests  63 ,  65  which are positioned a distance D 1  from the respective long lateral surfaces  34 ,  36  from which the single spacers  62 ,  64  extend. A fourth reference plane P 4 , which is perpendicular to the top surface  24  and the first reference plane P 1 , intersects each of the crests  63 ,  65  and is positioned a distance D 3  from the first wide lateral surface  38 . 
         [0027]    Preferably, the first, second and third single spacers  60 ,  62 ,  64  are symmetric on either side of their respective crests  61 ,  63 ,  65 . Similarly, the first, second and third spacer pairs  50 ,  52 ,  54  are symmetric on either side of their respective nadirs  51 . Further, although the first, second and third single spacers  60 ,  62 ,  64  and the first, second and third spacer pairs  50 ,  52 ,  54  are described with curved convex and concave surfaces, it is also anticipated that these surfaces could be planar such that the cross-sections of the single spacers  60 ,  62 ,  64  and each side of the spacer pairs  50 ,  52 ,  54  are triangular or trapezoidal as shown in  FIGS. 4 and 5 , respectively. 
         [0028]    The preferred embodiment of the paving stone  20  will have the following relative dimensions:
       (1) the length (L) of each of the first and second long lateral surfaces  34 ,  36  is equal to twice the width (W) of a wide lateral surface  38 ,  40  plus the width of the gap between two adjacent, interlocked paving stones. This gap width is equal to distance D 1  plus distance D 2  plus the standard clearance C between a spacer and spacer pair of interlocked paving stones. As used in the specification and the claims herein, the standard clearance C shall mean width of the clearance between a single spacer of one paving stone and a spacer pair of an adjacent paving stone. The standard clearance is typically 1 mm+/−0.5 mm. The length L can be calculated by the following: L=2W+D 1 +D 2 +C;   (2) the distance D 3  is equal to one-half of the width (W) of a wide lateral surface  30 ,  32  and can be calculated by the following: D 3 =W/2;   (3) each of the single spacers  60 ,  62 ,  64  are identically sized and shaped;       
 
         [0032]    (4) each of the spacer pairs  50 ,  52 ,  54  are identically sized and shaped. 
         [0033]    The preferred dimensions of the paving stone  20  are as follows:
       (1) the length (L) of each of the first and second long lateral surfaces  34 ,  36  is 244 millimeters;   (2) the width (W) of each wide lateral surface  38 ,  40  is  117  5 millimeters;   (3) the distance D 1  of each spacer crest from its respective lateral surface is 6 millimeters;   (4) the distance D 2  of the nadir  51 ,  58 ,  59  of each spacer pair from its respective lateral surface is 25 millimeters;   (5) the width of each single spacer  60 ,  62 ,  64  as measured along its respective long or wide side is 38 millimeters;   (6) the width of each spacer pair  50 ,  52 ,  54  as measured along its respective long or wide side is 64 millimeters;   (7) the thickness of each paving stone  20  is 80 millimeters. With these dimensions, the open area between adjacent paving stones  20  in a combination of multiple paving stones  20  forming a hardscaped surface area, the open area between the pavers will be approximately eight percent (8%) of the hardscaped area and will meet industry standards.       
 
         [0041]    The relative dimensions set forth supra allow a plurality of the paving stones  20  described with reference to  FIG. 1-3  to be combined to form a hardscape surface of varying patterns. As shown in  FIG. 6 , multiple paving stones  20  may be combined into a running bond pattern. Except for those single spacers (not shown) that may be located around the perimeter of hardscape, each single spacer  60 ,  63 ,  64  is interlocked with a trough defined by a corresponding spacer pair  46 ,  52 ,  54  to inhibit movement of one paving stone  20  with respect to another and insure the preferred spacing between the paving stones  20 . As used in the specification and claims herein, “interlocking” or “interlocked” means that a single spacer of one paving stone is positioned within the volume defined by the trough of the corresponding spacer pair similar of an adjacent paving stone with a standard clearance C between the single spacer and corresponding spacer pair. 
         [0042]    In the runner bond configuration shown in  FIG. 6 , the first single spacer  60  of each paving stone  20  is interlocked with the first spacer pair  46  of an adjacent paver. The second single spacer  62  of each paving stone  20  is interlocked with the third spacer pair  54  of an adjacent paving stone  20 ; and the third single spacer  64  of each paving stone  20  is interlocked with the second spacer pair  52  of an adjacent paving stone  20 . 
         [0043]    As shown in  FIG. 7 , multiple paving stones  20 ,  20 ’ may be combined into a herringbone pattern. In this configuration, the paving stones  20  are all aligned in a first direction in a series of stepped patterns such that the second single spacer  62  of each paving stone  20  is interlocked with the third spacer pair  54  of an adjacent paving stone  20 . The paving stones  20 ′ are all aligned in a second direction which is perpendicular to the first direction and are also aligned in a series of stepped patterns such that the third single spacer  64 ′ of each paving stone  20 ′ is interlocked with the second spacer pair  52 ′ of an adjacent paving stone  20 ′. 
         [0044]    Also, in this configuration, each of the paving stones  20  interlock with adjacent paving stones  20 ′ as follows: (1) the first single spacer  60 ′ of each paving stone  20 ′ interlocks with the second spacer pair  52  of a paving stone  20 ; (2) the second single spacer  62 ′ of each paving stone  20 ′ interlocks with the first spacer pair  46  of a paving stone  20 ; (3) the first spacer pair  46 ′ of each paving stone  20 ′ interlocks with the third single spacer  64  of a paving stone  20 ; and (4) the third spacer pair  54 ′ of each paving stone  20 ′ interlocks with the first single spacer  60  of a paving stone  20 . 
         [0045]    As shown in  FIG. 8 , multiple paving stones  20 ,  20 ′ may also be combined into a basketweave pattern. In this configuration, two paving stones  20  oriented in a first direction are arranged with their long sides  23  being adjacent such that the third single spacer  64  of each paving stone  20  interlocks with the third spacer pair  54  of the adjacent paving stone  20 . In this manner, a set of paving stones  20  oriented in a first direction is formed. 
         [0046]    Also in this configuration, two paving stones  20 ′, oriented in a second direction, are also arranged with their long sides  28 ′ being adjacent such that the third single spacer  64 ′ of each paving stone  20 ′ interlocks with the third spacer pair  54 ′ of the adjacent paving stone  20 ′. In this manner, another set of paving stones  20 ′ is formed oriented in a second direction which is perpendicular to the first direction. To complete the basketweave pattern, additional sets of paving stones  20  and sets of paving stones  20 ′ are arranged in an alternating checkerboard pattern as shown in  FIG. 8 . 
         [0047]    In this basketweave configuration, each of the paving stones  20  interlock with adjacent paving stones  20 ′ as follows: (1) the first single spacer  60  of each paving stone  20  interlocks with second spacer pair  52 ′ of a paving stone  20 ′; (2) the second single spacer  62  of each paving stone  20  interlocks with the first spacer pair  46 ′ of a paving stone  20 ′; (3) the first spacer pair  46  of each paving stone  20  interlocks with the second single spacer  62 ′ of a paving stone  20 ′; and (4) the second spacer pair  52  of each paving stone  20  interlocks with the first single spacer  62 ′ of a paving stone  20 ′. 
         [0048]    The present invention is described above in term of a preferred illustrative embodiment of a specifically-described paving stone. Those skilled in the art will recognize that alternative constructions of such an apparatus can be used in carrying out the present invention. Other aspects, features, and advantages of the present invention may be obtained from a study of this disclosure and the drawings, along with the appended claims.

Summary:
A paving stone for interlocking with similar adjacent paving stones, having a rectangular block shape. Three single spacers and three spacer pairs extend from the paving stones&#39; lateral surfaces. Each single spacer and each spacer of the spacer pairs have a crest positioned a distance D1 from the lateral surface. Two of the spacer pairs and two of the single spacers are respectively positioned opposite one another on the long lateral surfaces. One of the spacer pairs and one of the single spacers is positioned on the short lateral surfaces. When used with other paving stones having the same features, the single spacers of one paving stone are positioned in troughs of the spacer pairs of another paving stone to provide a structural interlock and create narrow joints between adjacent paving stones. Multiple paving stones can be aligned in multiple configurations, such as herringbone, runner bond, and basketweave patterns.