Abstract:
A paver support system includes an edging rail or bracket that engages an underlayment layer. The paver support system contains a plurality of paving elements within a prescribed area bordered by the edging rail and supported on the underlayment layer. The cooperating underlayment layer and edging rail are self-supporting to maintain the relative spatial relationship of the plurality of paving elements supported thereon.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    This invention relates, in general, to edging structures. In particular, this invention relates to paver element supports that are part of a self-supporting paver system. Traditional edge restraint systems use spikes that are anchored to the ground to hold the edge restraint relative to the individual paving elements. One limitation of using spikes to hold the edging in place is that the spikes need a compacted base under the bedding sand to act as an anchoring structure. If there is no compacted base, the spikes will not hold the edging in place very effectively. Further, the edging material is anchored to the ground surrounding the paved walkway, for example. Any shifts in the bedding that supports the paver elements will cause the edging to move relative to the pavers, thus disrupting the perimeter containment of the paver elements. Thus, it would be desirable to provide a paving system that is generally self supporting and does not rely on a compacted bed to stabilize the paving elements. 
       SUMMARY OF THE INVENTION 
       [0002]    This invention relates to a retaining structure that cooperates with an underlayment material to support and contain the relative location of paving elements. The cooperating retaining structure is in the form of an edging rail that, together with the underlayment layer, defines a self supporting paving system. In one embodiment, the self supporting paving system comprises an underlayment layer and an edging rail configured to be fixed to the underlayment layer such that the edging rail and the underlayment layer are adapted to cooperate to fully support a plurality of paver elements atop of a support surface. 
         [0003]    In another exemplary embodiment, the paving system includes a retaining structure in the form of an edging rail or bracket that includes piercing barbs. The piercing barbs are configured to engage an underlayment sheet, such as a polymer foam sheet, and form an outer perimeter frame. The edging rail and underlayment layer are placed on soil or a prepared surface, such as for example compacted sand. Paving elements may then be placed on and supported by the underlayment layer and the edging rail. The paving elements are bounded, at least along a portion of the perimeter of the paved area, and are thus spatially contained on the surface of the underlayment by the edging rail. 
         [0004]    Various aspects of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]      FIG. 1  is an elevational view, in partial cross section, of a paving system having an underlayment layer and an edging rail that support and contain a plurality of paving elements. 
           [0006]      FIG. 2  is a perspective view of an embodiment of an edging rail configured for use with an underlayment layer of a self-supporting paving system. 
           [0007]      FIG. 3  is a plan view of the edging rail of  FIG. 2  showing an underlayment attachment structure. 
           [0008]      FIG. 4  is an elevational view of the edging rail of  FIG. 2 . 
           [0009]      FIG. 5  is an end view of the edging rail of  FIG. 2 . 
           [0010]      FIG. 6  is an enlarged plan view of an alternative embodiment of an edging rail having an underlayment attachment structure. 
           [0011]      FIG. 7  is yet another alternative embodiment of an edging rail having an underlayment attachment structure. 
           [0012]      FIG. 8  is a perspective view of another embodiment of an edging rail configured for use with an underlayment layer of a self-supporting paving system. 
           [0013]      FIG. 9  is a plan view of the edging rail of  FIG. 6  showing an underlayment attachment structure and further having frangible elements. 
           [0014]      FIG. 10  is an embodiment of an edging rail having an underlayment attachment structure and frangible elements. 
           [0015]      FIG. 11  is a perspective view of an edging rail having severable linking elements that are selectively removable to form a contoured configuration. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0016]    Referring now to the drawings, there is illustrated in  FIG. 1  a paving system, shown generally at  10 , having an edging rail or bracket  12  and an underlayment support layer  14  that supports a plurality of paving elements  16 . The paving elements are shown as perimeter paving elements  16   a  and interior paving elements  16   b.  The paving system  10  is a self-supporting structure that confines the paving elements  16  within a defined area. The containment area of the paving elements  16  is defined generally as a perimeter of the underlayment layer  14  that is bounded by the edging rail  12  and also the supporting surface of the underlayment layer  14  positioned below the pavers. The self supporting characteristic of the paving system  10  confines the paving elements  16  together such that disruptions of a supporting base foundation have a minimized impact on the arranged pavers. This minimizing effect reduces or prevents heaving or separation of the arranged paving elements  16 . The edging rail  12  and the underlayment layer  14  of the self supporting paving system  10  are connected to function as a unitary body that supports and contains the paving elements  16  in both a lateral and a vertical direction relative to a supporting base foundation. The paving system  10  may be placed over a layer of sand  18 , that may be compacted over a layer of subgrade soil  20 . Alternatively, the sand layer  18  may be raked, washed in, or otherwise topically applied. The sand layer  18  may be used to facilitate water drainage and/or to provide a consistent, graded surface formed to the desired elevation. The sand layer  18  may be omitted, if desired. The subgrade soil layer may be undisturbed, virgin soil; graded soil; or compacted material that may include stone, sand, asphalt, concrete, and the like. 
         [0017]    The underlayment support layer  14  may be formed from a polymer foam, such as a polyethylene foam, a polypropylene foam, a polystyrene foam, and the like. The underlayment layer  14  may be a closed cell foam that is water-impervious. Alternatively, the underlayment layer  14  may provide for water drainage. Such water drainage may include one or more drain holes formed through the underlayment. The one or more drain holes may cooperate with one or more drainage channels. The drainage channels may be on the top support surface and/or the bottom surface of the underlayment layer  14 . Alternatively, the underlayment layer  14  may have foam beads having interstitial voids formed therebetween to allow for water flow through the layer. 
         [0018]    The edging rail  12  is illustrated, in cross-section, as a generally “L” shaped bracket having two legs  22  and  24 . The bracket legs  22  and  24  are shown as having equal lengths, though legs of unequal lengths may be provided. The first leg  22  of the edging rail includes a surface  26  configured to support the underlayment layer  14 . This underlayment support leg  22  includes one or more piercing barbs  28  formed into the leg that extend toward the underlayment layer  14 . The barbs  28  are shown as triangular barbs having a point  30  configured to pierce through and retain the relative position of the edging rail  12  to the underlayment  14 . The barbs  28  may alternatively be rectangular, star shaped, semi-circular cylindrical projections, and the like. Alternatively, the barbs  28  may be separate structures similar to nails that are secured to the first leg by any means, such as welding, bonding, or frictional engagement. 
         [0019]    The second leg  24  of the edging rail  12  is illustrated extending in a generally perpendicular orientation to the first rail  22 . It should be understood that the second rail  24  may extend at any desired relative angle or multiple relative angles to the first rail  22 . Thus, the second leg  24  may be straight or have a contoured shape. An outer perimeter edge  32  of the underlayment  14  may locate against the second leg  24 . The plurality of paving elements  16  may be placed on the underlayment layer  14  in any desired pattern or arrangement. The outermost edge paving elements, or perimeter paving elements  16   a,  abut a portion of the second leg  24 . The interior paving elements  16   b,  adjacent to the edge paving elements  16   a  (and other interior paving elements) may directly abut the edge paving elements  16   a  or may have a layer of bedding material (not shown), such as sand, infill, expansion material, and the like disposed therebetween. 
         [0020]    Referring now to  FIGS. 2-5 , there is illustrated an embodiment of an edging rail  112  having first and second legs  122  and  124 . The first leg  122  includes a plurality of barbs  128  disposed between windows  140  formed into the first leg  122 . The windows  140  may be omitted if so desired. The barbs  128  and the windows  140  may be stamped, cut or otherwise formed into the first leg  122 . The barbs  128  are generally shown having a triangular shape that extends upwardly toward the underlayment  14  and having a piercing point  130  and generally flat sides or faces  130   a  and  130   b.  The generally flat faces  130   a  and  130   b  are all positioned in parallel planar orientations, as shown in  FIG. 5 . Alternatively, the barbs  128  may be positioned in a perpendicular arrangement or any other angular orientation relative to each other. In addition to the barbs  128 , nail holes  142  may be provided to permit external anchoring of the edge rail  112  to the surrounding soil or other support structure. 
         [0021]    Referring now to  FIGS. 6 and 7 , there are illustrated alternative arrangements of barbs, positioned at relative angles to each other. As shown in  FIG. 6 , primary barbs  228   a  are formed into a first leg  222 , that is shown perpendicularly oriented relative to a second leg  224 , where flat faces  230   a  and  230   b  are oriented along generally parallel planes. The primary barbs  228   a  are staggered relative to one another so that they are spread over most of the width of the first leg  222 . The first leg  222  is shown having optionally formed windows  240  that are partially bounded by a front tie  244  and, optionally, a back flange  246  between the window  240  and the second leg  224 . 
         [0022]    The front tie  244  is configured to be readily severable by way of light hand tools, such as pliers, tin snips, and the like. Thus, as will be explained below, the edging rail  212 , as well as other embodiments described herein, may be contoured to follow the perimeter of the underlayment. In order to be cut and bent, the edging is preferably formed from a relatively thin material. The edging rail  12  may be formed from metal, including sheet metal, or plastic, including thermoplastics, fiberglass/resin composites, and the like. Sheet metal materials may be on the order of a Gauge 3 or greater, and may be more specifically provided between a Gauge 10 and Gauge 15 thickness. Plastic and non-metallic materials may be thicker, if so desired. 
         [0023]    Secondary barbs  228   b  are shown formed into the front tie  244  and having flat sides that are oriented in a generally perpendicular orientation relative to the primary barbs  228   a.  The barbs  228   a  and  228   b  have their broad surfaces oriented in two perpendicular planes to restrain the underlayment  14  in two directions. This barb orientation further prevents substantial cutting or elongation of the pierced holes in the underlayment  14  by the thin edge of the barbs  228   a  and  228   b  in one plane by virtue of the broad surface in the other plane. Alternatively, the secondary barbs  228   b  may also be positioned adjacent to the primary barbs  228   a  between the windows  240  or in lieu of the windows  240 . As shown in  FIG. 7 , the primary barbs  228   a  may be positioned in a row closer toward the center of the first leg  222 . The back flange  246  is preferably narrow to permit the second leg  224  to be bent or formed to follow the contour of the intended pathway or shape of the paved area, as will be described below. The embodiments of  FIGS. 6 and 7  show optional nail holes  242  formed into the first leg  222  to provide for nails, spikes, or staples to anchor the edging rail to the base layer, if so desired. 
         [0024]    Referring now to  FIGS. 8 and 9 , there is illustrated another embodiment of an edging rail, shown generally at  312 , that includes first and second legs  322  and  324 , respectively, and barbs  328  that may be similar in geometry and relative orientation to the barbs  28 ,  128 , and  228   a,b  described above. The first leg  322  includes frangible elements  350  positioned on a front tie  344  along a window  340  between spaced-apart underlayment anchoring sections having the extending barbs  328 . The barbs  328  may be oriented in any desired relative position. Additionally, the frangible elements  350  may also include barbs (not shown), similar to secondary barbs  228   b  described above. The frangible elements  350  are defined by scribes  352  configured as thinner section score marks formed onto the front tie  344 . The scribes  352  may be formed on one side of the first leg  322  or both upper and lower sides. The scribes  352  may be bounded by chamfers  354  on either end or both ends to facilitate removal of the frangible elements  350 . When selected frangible elements  350  are removed, the second leg  324  and a back flange  346  may be formed to correspond to the contour of the paved area perimeter. The frangible elements  350  may be left connected to provide for straight sections of pavement. In order to bend or contour the edging  312  according the shape of the desired pathway, the frangible elements  350  may be removed by breaking or cutting. The frangible elements  350  may be broken using light hand tools, such as pliers, where the element  350  is bent back and forth to fatigue the front tie  344  at the scribes  352 . Alternatively, the frangible elements  350  may be more easily cut by light hand tools, such as tin snips, at the scribes  352 . Once the frangible elements  350  are removed, the second leg  324  may be more easily bent, contoured, or otherwise formed to conform to the edge of the paved area and provide better attachment to the underlayment layer  14 . 
         [0025]    Referring now to  FIG. 10 , there is illustrated an embodiment of an edging rail  412  having a first leg  422  and a second leg  424 . The first leg  422  includes an alternative arrangement of barbs  428 , shown having one barb  428   a  arranged generally parallel to the second leg  424  and two barbs  428   b  and  428   c  oriented generally at 45 degree angles to the second leg  424  and perpendicular to each other. The first leg includes a window  440  having a front tie  444  and a reduced or minimal-width back flange  446 . In other embodiments, the back flange  446  may be removed. The front tie  444  includes a single scribe  452  that may be optionally bounded by chamfers  454 . The single scribe  452  is positioned generally in the center of the front tie  444  and, when broken, forms two halves of the front tie  444 . Alternatively, the scribe  452  may be located anywhere along the front tie  444  and may form one extra tie leg. The two halves of the front tie  444  may be bent up to provide additional securement with the underlayment  14  or may be bent down into the subgrade to prevent shifting of the paver system relative to the ground. 
         [0026]    Referring now to  FIG. 11 , there is illustrated another embodiment of an edging rail, shown generally at  512 . The edging rail  512  includes first and second legs  522  and  524 , respectively. The first leg  522  is illustrated having windows  540  bordered by a front tie  544  that is positioned opposite the second leg  524 . The front tie  544  may be severed in order to bend the second leg to form a contour, such as a curve with a radius, R. Alternatively, the front tie  544  may include one or more scribes or a frangible element (not shown) to facilitate the severing and bending operations. The bends in the second leg  524  may be formed in any desired direction, for example, such as is illustrated in  FIG. 11  or in an opposite direction of curvature. The first leg  522  is illustrated having a plurality of attachment holes  542  that are each configured to accept an anchor  528 . The anchor holes  542  may be omitted such that the anchors  528  are pierced through the first leg  522 . The edging rail  512  is illustrated as a multiple component assembly where the plurality of anchors  528  are inserted through the first leg  522  and extend upwardly to engage the underlayment  14 . The anchors  528  may be frictionally engaged within the holes  542  or may be bonded, glued, welded, or otherwise attached to the first leg  522 . 
         [0027]    The principle and mode of operation of this invention have been explained and illustrated in its preferred embodiment. However, it must be understood that this invention may be practiced otherwise than as specifically explained and illustrated without departing from its spirit or scope. Furthermore, each of the elements illustrated and described with respect to each embodiment may be incorporated into any other embodiment or substituted for another element in another embodiment.