Abstract:
A wire mesh sandwich construction which comprises an array of line wires, an array of cross wires overlying said array of line wires and a barrier material disposed between the array of line wires and the array of cross wires. The array of line wires is spaced apart from the array of cross wires to form points of intersection therebetween. The array of line wires is joined to said array of cross wires at the points of intersection and through the barrier material, thus securing the barrier material between the array of line wires and the array of cross wires.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     This invention relates generally to wire mesh sandwich constructions and in particular to wire mesh sandwich constructions that can be used for general fencing applications, e.g., fencing that is used to control erosion at construction sites.  
         [0003]     2. Description of the Prior Art  
         [0004]     Residential, commercial, and industrial constructions sites produce voluminous piles of loose and compacted piles of soil that are susceptible to erosion by wind and rainfall. One way in which to staunch such erosion from contaminating environmentally sensitive areas situated adjacent to industrial and commercial construction sites includes the erection of a silt fence.  
         [0005]     Silt fences currently in use typically comprise a wire fabric that includes a welded or woven wire mesh having a front surface and a back surface and a ply of barrier material. The barrier material is usually a woven or non-woven plastic geotextile. It is secured to the wire mesh by clips or ties to the front surface or optionally the back surface of the wire mesh. The wire fabric can be supported in a substantially perpendicular manner from the ground by stakes, which are positioned along a boundary to separate an environmentally sensitive area from a construction site. The barrier material obstructs the travel of the eroding piles of earth produced at the construction site to the environmentally sensitive areas.  
         [0006]     The practice of erecting the silt fences entails attaching the barrier material to the front or optionally the back surface of the wire mesh. The wire mesh supports the barrier material attached thereto. The mesh with the barrier material attached can then be raised in a substantially perpendicular manner from the ground with the stakes. Attaching barrier materials to the front or optionally the back surface of the wire mesh is time consuming and increases the costs that are associated with the assembly and erection of the silt fence. Moreover, while the slit fence is in service, tears in the attached barrier material tend to develop at stress points where the material is clipped or tied to the wire mesh. These tears in the barrier material require continued maintenance.  
         [0007]     A need exists, therefore, for an improved product that can be used for erosion control, e.g., when used to construct a silt fence, that addresses the aforementioned problems.  
       SUMMARY OF THE INVENTION  
       [0008]     In one aspect, the invention comprises a wire mesh sandwich construction which includes an array of line wires, an array of cross wires overlying said array of line wires and a barrier material disposed between the array of line wires and the array of cross wires. The array of line wires is spaced apart from the array of cross wires to form a grid pattern with points of intersection therebetween. The array of line wires is joined to the array of cross wires at the points of intersection and through the barrier material, thus securing the barrier material between the array of line wires and the array of cross wires.  
         [0009]     In another aspect, the invention comprises a method for making a wire mesh sandwich construction which includes the steps of providing an array of line wires, overlaying a barrier material onto the array of lines wires to form a layered construction, placing an array of cross wires on top of the barrier material to form a mesh construction having points of intersection between said array of line wires and said array of cross wires, and welding the array of line wires to the cross wires through the barrier material at the points of intersection to form the wire mesh sandwich construction.  
         [0010]     In yet another aspect, the invention comprises a method for making a wire mesh sandwich construction which includes the steps of providing an array of line wires, overlaying a barrier material having perforations therein onto the array of line wires to form a layered construction, placing an array of cross wires onto the barrier material to form a mesh construction having points of intersection between the array of line wires and the array of cross wires that are in registration with the perforations and welding that array of line wires to the array of cross wires through said perforations at the points of intersection to form the wire mesh sandwich construction.  
         [0011]     These and other objects, features and advantages of the present invention will become more apparent in light of the following detailed description of the preferred embodiments thereof, as illustrated in the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]      FIG. 1  is a partial perspective view of a wire mesh sandwich construction with portions of the wire mesh sandwich construction broken away;  
         [0013]      FIG. 2  is a partial side view of the silt fence with a portion of the fence broken away;  
         [0014]      FIG. 3  is a sectional view of  FIG. 2  taken along lines  1 - 1 ;  
         [0015]      FIG. 4  is a sectional view of  FIG. 2  taken along lines  2 - 2 ;  
         [0016]      FIG. 5  is a sectional view of  FIG. 2  taken along lines  3 - 3 ; and  
         [0017]      FIG. 6  is a schematic illustration of a system for manufacturing a silt fence. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0018]     With reference initially to  FIGS. 1 and 2 , a wire mesh sandwich construction is generally depicted at  10 . The wire mesh sandwich construction  10  is comprised of an array of line wires  12  positioned over an array of cross wires  16  to form a mesh construction  15 . A barrier material  14  is positioned between the array of line wires  12  and the array of cross wires  16 . The array of line wires  12  and the array of cross wires  16  can be comprised of wires drawn from ferrous or non-ferrous rod. The wires can then be surface coated for protection or aesthetic purposes. The barrier material  14  can be comprised of plastics, wovens, non-wovens, natural weaves, e.g., canvases, papers, and admixtures of natural and synthetic fibers. Commercial examples of the barrier material  14  can include DuPont Tyvex, Beltech woven polypropylene geosynthetic geotextile, Amcon woven geotextiles or woven coated polypropylene geosynthetics, Airspace Saver (Fabrene) high density woven polyethylene coated fabric with polyester straps, Exxon geotextile (3601), Fabrene high tensile strength lightweight woven polyethylene, GeoCover geotextile (601) and GSE high-density polyethylene geomembrane. As shown in the broken away portions of  FIGS. 2 and 3 , the line wires  12  and cross wires  16  are welded, e.g. resistance welded or pressure welded, together at cross over locations  18 .  
         [0019]     Referring to  FIG. 3 , a sectional view of  FIG. 2  is shown taken along lines  1 - 1 . The material  14  is positioned between the cross wire  16  and the line wire  12 . Referring to  FIG. 4 , a sectional view of  FIG. 2  is shown taken along lines  2 - 2 . The line wire  12  is welded to the cross wire  16  through the barrier material  14  at the cross over location  18 . In an alternative embodiment, the line wire  12  is welded to the cross wire  16  through a perforation in the material  14  at the cross over location  18 . Referring to  FIG. 5 , a sectional view of  FIG. 2  is shown taken along lines  3 - 3 . The barrier material  14  is positioned between the line  12  and the cross wires  16 .  
         [0020]     With reference to  FIG. 6 , a schematic illustrating a system for manufacturing the wire mesh sandwich construction  10  is shown. The system  100  includes a first station  120 , a second station  122 , a third station  124 , a fourth station  126 , a fifth station  128 , a sixth station  130  and a seventh station  132 .  
         [0021]     A longitudinally spaced array of line wires  112  is drawn from the first station  120  and conveyed to a second station  122 , which comprises a roll  123  of barrier material  114 , e.g., a woven geotextile fabric that conforms to the requirements of Specification No. DMS-6230 (2003) of the Texas Department of Transportation. The wires in the array of line wires  112  are spaced apart one from the other at a distance of 4 inches, are made of galvanized steel and have nominal diameters of 0.099 or optionally 0.080 inches. The barrier material  114  is drawn from the roll  123  and overlaid on the array of line wires  112  to form a layered construction (not shown). The layered construction is conveyed to the fifth station  128  whereupon a longitudinally spaced array of cross wires  116  is drawn from a fourth station  126  over the barrier material  114  of the layered construction. The array of cross wires  116  is transverse to the array of line wires  112  and forms a grid pattern (not shown) having points of intersection between the array of cross wires  116  and the array of line wires  112 . The wires in the array of cross wires  116  are spaced one from the other at a distance of 2 inches, are made of galvanized steel and have nominal diameters of 0.099 inches or optionally 0.080 inches. The layered construction is conveyed to a fifth station  128  wherein the array of cross wires  116  are resistance welded to the array of lines wires through the barrier material  114  and at the points of intersection by direct current thereby forming the wire mesh sandwich construction. Subsequently, the wire mesh sandwich construction is indexed forward to and coiled at a seventh station  132 .  
         [0022]     In an alternative embodiment, the layered construction is conveyed to a third station  124 , which comprises a fabric perforator prior to be drawn to the fifth station  128 . The barrier material  114  of the layered construction is perforated by heating, e.g., the application of hot tips, such that the resulting perforations will register with the points of intersection. At the fifth station  128 , the array of cross wires  116  is resistance welded to the array of line wires  112  through the perforations of the barrier material  114  and at the points of intersection by alternating current to form the wire mesh sandwich construction.  
         [0023]     In operation, the overlaying of the barrier material  114  onto the array of line wires  112  to form the layered construction, the drawing of the array of cross wires  116  over the barrier material  114  of the layered construction, the optional perforating of the barrier material  114  and the resistance welding of the array of cross wires  116  to the array of line wires  112  through the barrier material  114 , or optionally through the perforations, at the points of intersection to form the wire mesh sandwich construction can occur in rapid or slow succession. Once the wire mesh sandwich construction is formed, the same is then indexed forward to the seventh station thereby drawing the barrier material  114  from the roll  123 .  
         [0024]     In another embodiment, the wire mesh sandwich construction can be indexed to a sixth station  130  prior to being indexed to the seventh station  132 . The sixth station  130 , which comprises slitters, is used to shear any wires of the array of cross wires  116  that extend beyond the array of line wires  112 .  
         [0025]     In addition, to silt fences, it is contemplated that the wire mesh sandwich construction can also be used for any purposes where a barrier is needed, e.g., gabion baskets and mattresses for retaining earth, bastions, cages for entrapping aquatic fauna, security fencing, privacy screens, snow-fencing and any other general fencing applications.  
         [0026]     Although the present invention has been shown and described with a preferred embodiment thereof, various changes, omissions and additions to the form and detail thereof, may be made therein, without departing from the spirit and scope of the invention.