Abstract:
A beach renourishment sand snare and a method or its employment. A series of metal posts are embedded in the sand, forming a line which is approximately perpendicular to the shore. Semi-rigid mesh panels are slidably placed and secured between adjacent posts. Each mesh panel, once immersed in the surf, tends to acumulate sand. The sand will eventually accumulate to the point that the shoreline will advance seaward of the mesh panel. Once this occurs the particular mesh panel is removed and transferred to the seaward end of the line of posts. Likewise, the posts on the landward side can be removed and transfered to the seaward side, thereby “walking” the assembly to seaward. The process thereby accumulates sand and advances the shoreline.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     Not Applicable 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable 
     MICROFICHE APPENDIX 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to the field of beach and shoreline renourishment. More specifically. the invention comprises a modular water-permeable fence assembly designed to impede the flow of suspended particles—thereby producing sand accretion. A method for deploying the fence assembly is also disclosed. 
     2. Description of the Related Art 
     Beach and shoreline erosion is a recognized problem in many areas. Erosion and accretion are natural processes whereby shorelines advance and retreat over time. Where structures are erected on the shoreline, however, the natural erosion jeopardizes property having substantial economic worth. 
     Various methods have been used to impede or prevent beach erosion. It has long been known that suspending a mesh or net in the water near the beach tends to cause an accumulation of sand in the region of the net. One such device is disclosed in U.S. Pat. No. 3,564,853 to Csiszar (1969) Another approach based on the same concept is disclosed in U.S. Pat. No. 4,089,179 to Trautman (1978). Both these inventions require the deployment of supporting pilings or anchors a considerable distance offshore. 
     In recent years, efforts have focused on the use of fence structures arrayed in a direction perpendicular to the beach. One such fence structure is disclosed in U.S. Pat. No. 4,710,056 to Parker (1987). The Parker device uses a line of flexible mesh suspended from evenly spaced supports. The supports are actually three-legged structures, with each leg being driven or buried in the sand at an angle for added stability. While the Parker device does succeed in accumulating sand, the mesh employed tends to become buried. Both the buried mesh and the submerged portions of the support legs become exceedingly difficult to remove. The tendency of the fence structures to become submerged and stuck within the sand they accumulate is, in fact, one of the most significant recognized problems with this approach. 
     U.S. Pat. No. 5,255,997 to Bailey et.al. (1993) provides an excellent explanation of this self-burial phenomenon. FIG. 11 of the Bailey disclosure illustrates mesh panels capable of sliding up and down on their supporting poles. As the text explains, the panels tend to sink within the deposited material (river mud), until their downward progress is checked by restraining straps. 
     A device which is capable of adjusting the height of the mesh deployed is disclosed in U.S. Pat. No. 5,720,573 to Benedict et.al. (1998). As seen in FIG. 1, the Benedict device incorporates a rigid horizontal rod which spools up the mesh fabric and prevents unwanted immersion in the accumulated sand. Several versions are disclosed, including one where the height of adjacent mesh panels is adjustable somewhat independently (see FIG. 14). FIG. 15 of the Benedict disclosure shows mesh panels mounted in a rigid frame. These panels can presumably be raised and lowered with respect to the support pilings. It is important to realize, however, that the panels are subject to considerable force from wave impact. Ideally the waves travel in a direction which is perfectly perpendicular to the fence, but this is often not the case. It is therefore important to secure the fence panels to the support pilings so that the panels cannot bend and thereby escape the securing device. The arrangement shown in the &#39;573 disclosure obviously does not address this concern. In addition, the &#39;573 disclosure requires the use of bulky external brackets to the support pilings. 
     FIG. 17 of the &#39;573 disclosure is generally instructive regarding the use of fence structures, as it shows a plan view of several fence structures deployed along a shoreline. The array illustrated is typical of how these devices are used; i.e., a series of several fence structures is needed. 
     Accordingly, the prior art devices are limited in that they: 
     1. Require the deployment of pilings or support structures a considerable distance from shore; 
     2. Do not provide means for preventing the burial of the fence material used, 
     3. Are insufficiently rigid to resist wave forces; and 
     4. Require the addition of external brackets on the pilings. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention comprises a beach renourishment sand snare and a method for its employment. A series of metal posts are embedded in the sand, forming a line which is approximately perpendicular to the shore. Each post has a pair of slots cut vertically down its side, with the slots all lining up in a direction which is perpendicular to the shore. Semi-rigid mesh panels are constructed of polymer coated wire mesh. Each side of the mesh panel is enclosed in a clamping assembly. Each clamping assembly is configured to slide into the slots cut into the posts, with means provided to secure the clamping assembly in place in the slot. Thus, a mesh panel may be lowered into place and secured between adjacent posts by sliding the clamping assemblies on either side of the mesh panel into the slots in the two adjacent posts. 
     A method of applying the sand snare is also disclosed. The placement of the mesh panel in the surf tends to accumulate sand around the panel. The sand will eventually accumulate to the point that the shoreline will advance seaward of the mesh panel. Because each mesh panel is independently placed, once the shoreline has advance past its position, that panel can be removed and transferred to the seaward end of the line of posts. Likewise, the posts on the landward side can be removed and transferred to the seaward side once they are no longer needed—thereby extending the line of posts. In this fashion, a series of posts and mesh panels can be “walked” into the sea, accumulating sand and advancing the shoreline indefinitely. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     FIG. 1 is an isometric view, showing the wire mesh material. 
     FIG. 2 is an isometric view, showing the wire mesh in greater detail. 
     FIG. 3 is an isometric view, showing the application of the clamping assemblies to the wire mesh panel. 
     FIG. 4 is an isometric view, showing how the brackets are affixed to the mesh panel 
     FIG. 5 is an isometric view, showing the completed panel assembly. 
     FIG. 6 is an isometric view, showing a post. 
     FIG. 7 is an isometric view with a cutaway, showing the rear base. 
     FIG. 8 is a perspective view, showing how a panel assembly slides into adjoining posts. 
     FIG. 9 is a perspective view, showing how a panel assembly slides into adjoining posts. 
     FIG. 10 is a top view of the clamping assembly held within the post. 
     FIG. 11 is an isometric view, showing the application of the device to renourish a beach. 
     FIG. 12 is an isometric view, showing the renourishment process. 
     FIG. 13 is an isometric view, showing the renourishment process. 
     FIG. 14 is an isometric view, showing the renourishment process. 
     FIG. 15 is an isometric view, showing the renourishment process. 
     FIG. 16 is an isometric view, showing the renourishment process. 
     FIG. 17 is an isometric view, showing the renourishment process. 
     FIG. 18 is an isometric view, showing the preferred embodiment. 
     FIG. 19 is an isometric view, showing the installation of the preferred embodiment in a post 
     FIG. 20 is a top view, showing the installation of the preferred embodiment in a post 
     
       
         
               
             
               
               
               
               
               
             
           
               
                   
               
               
                 REFERENCE NUMERALS IN THE DRAWINGS 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 10 
                 mesh panel 
                 12 
                 vertical rod 
               
               
                   
                 14 
                 horizontal rod 
                 16 
                 welds 
               
               
                   
                 18 
                 back bracket 
                 20 
                 jacking bracket 
               
               
                   
                 22 
                 jack member 
                 24 
                 jack brace 
               
               
                   
                 26 
                 fastener hole 
                 28 
                 female rivet 
               
               
                   
                 30 
                 male rivet 
                 32 
                 post 
               
               
                   
                 34 
                 slot 
                 36 
                 tube brace 
               
               
                   
                 38 
                 panel assembly 
                 40 
                 clamping assembly 
               
               
                   
                 42 
                 water 
                 44 
                 low tide line 
               
               
                   
                 46 
                 accumulation zone 
                 48 
                 alternate back bracket 
               
               
                   
                 50 
                 alternate jacking bracket 
               
               
                   
                   
               
             
          
         
       
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Those skilled in the art are aware that suspending a mesh material in the sand-laden water near a beach causes the suspended sand particles to fall out of suspension and accumulate on the bottom Flexible mesh materials have traditionally been used for this purpose, such as nylon nets similar to those used for fishing. 
     As the sand accumulates over the lower portions of the mesh material, the material becomes imbedded. Flexible netting is often difficult to remove, since the force necessary to pull the netting out of the sand is often sufficient to catastrophically tear the netting. Accordingly, the present invention employs a much more rigid mesh material. FIG. 1 shows a portion of a mesh panel  10 . The reader will observe that it is composed of evenly spaced vertical rods  12  joined to evenly spaced horizontal rods  14 . 
     FIG. 2 shows mesh panel  10  in greater detail. It is generally composed of steel wire having a diameter between 0.030 and 0.125 inches. The array of horizontal and vertical rods are joined by a series of welds  16 . Of course, mesh panel  10  is ultimately destined to be immersed in salt water. It is therefore critical that mesh panel  10  be coated with a corrosion inhibiting substance. One particularly effective method is to coat the completed weldment with synthetic rubber or other flexible and stable polymers. Those skilled in the art will realize that this technique is now employed in the construction of crab traps and the like. The coating prevents the salt water from contacting the metal, yet remains flexible so the coating will not fracture as the mesh twists. 
     FIG. 3 shows the assembly of several components. Mesh panel  10  is generally rectangular, having a lower edge, an upper edge, a first side edge, and a second side edge. The first side edge (to the left in the view as shown) is sandwiched between a back bracket  18  and a jacking bracket  20 . Likewise, the second side edge is also sandwiched between a back bracket  18  and a jacking bracket  20 . The reader will observe that the relative positions of the two brackets are transposed on opposite ends of mesh panel  10 . The reason for this will be explained subsequently. 
     FIG. 4 illustrates one method for joining the brackets to mesh panel  10 . Back bracket  18  and jacking bracket  20  are both pierced by a series of fastener holes  26 . When the two brackets are placed on opposite sides of mesh panel  10  as shown, these holes align. The holes also align with gaps between the rods comprising mesh panel  10 . One method of joining the two brackets to mesh panel  10  is placing rivets within the fastener holes  26  and crimping the rivets in place. Female rivet  28  and male rivet  30  are shown in the appropriate position for insertion. Those skilled in the art will appreciate that many other conventional fastening methods could be used—such as spot welding or crimping. 
     FIG. 5 shows the completed panel assembly  38 . Each set of back bracket  18  and jacking bracket  20 , along with any associated fasteners, is referred to as clamping assembly  40 . The reader will observe that both side edges of mesh panel  10  are clamped securely within a clamping assembly  40 . In this state, mesh panel  10  may flex somewhat, but it is sufficiently stiff to prevent folding 
     It is desirable to use identical brackets on the first side edge and the second side edge of mesh panel  10 . It is therefore necessary to swap the respective positions of back bracket  18  and jacking bracket  20  on the second side edge with respect to the first side edge. In FIG. 5, the clamping assembly  40  on the left side of the view has jacking bracket  20  in the foreground and back bracket  18  in the background. The clamping assembly  40  on the right side of the view has back bracket  18  in the foreground and jacking bracket  20  in the background. 
     Those skilled in the art will realize that once a particular mesh panel  10  has been in position for several days, its bottom edge will be mired in the accumulated sand. It often requires considerable force to lift mesh panel  10  clear. It is therefore advisable to have designated lift points attached to mesh panel  10 . The user can then manually apply force to these lift points or, in the alternative, apply a jacking mechanism. 
     Returning now to FIG. 4, the lift points will be explained. The reader will observe that the upper portion of jacking bracket  20  has jack member  22  welded to it at a right angle. The purpose of jack member  22  is to provide a horizontal surface to which a lifting force can be applied. Jack brace  24  is provided to reinforce jack member  22 . The addition of these elements causes jacking bracket  20  to be taller than back bracket  18 . Returning to FIG. 5, the reader will observe that each end of panel assembly  38  is provided with a lift point (though on opposite sides of the panel). 
     FIG. 6 shows post  32 . Post  32  is typically a hollow metal cylinder. As it must be immersed in salt water, it is advisable to fabricate this element from aluminum or coated steel. The lower portion of post  32  will be driven or dug into the sand during the installation process. The upper portion opens into a pair of vertical slots  34 . Those skilled in the art will realize that the addition of vertical slots  34  significantly weakens the structure of post  32 . Turning now to FIG. 7, the reader will observe that three tube braces  36  have been added to address this concern. Each tube brace  36  fits within a hole drilled through post  32  from side to side. Once in position, each tube brace  36  is welded in place. A similar result could be obtained using a threaded rod with accompanying nuts and washers. The intent is to reinforce the upper portion of post  32 , but the actual method of carrying out this reinforcement is not significant to the present invention. 
     FIG. 8 illustrates the installation of a panel assembly  40  within a pair of adjacent posts  32 . The two clamping assemblies  40  on either end of panel assembly  38  slide into the slots  34  in the two posts  32 . Panel assembly  38  is then lowered in the direction indicated by the arrows. FIG. 9 shows the same assembly with panel assembly  38  in the fully installed position. 
     FIG. 10 shows the left hand post  32  from the top. This view readily illustrates how clamping assembly  40  engages slot  34 . The reader will recall that both back bracket  18  and jacking bracket  20  are formed of angle iron (in the shape of the letter “L”). When viewed from the top, each bracket contains a flange which is parallel to mesh panel  10  and a flange which is perpendicular to mesh panel  10 . The perpendicular flanges obviously play an important role, as they bear against the interior cylindrical surface of post  32 . 
     Mesh panel  10  is often subjected to substantial lateral wave forces (from top to bottom or from bottom to top in the view as shown). When this occurs, mesh panel  10  comes under significant tension. This tension is transmitted to post  32  by the two flanges (of the two brackets) which extend perpendicularly outward from the plane of mesh panel  10 . These perpendicular flanges bear against the interior of post  32 . Thus, even under substantial lateral wave forces, mesh panel  10  is unable to pull free of post  32 . 
     The embodiment shown in FIG. 10 places the material of mesh panel  10  in direct contact with slot  34  in post  32 . This results in the coating on mesh panel  10  rubbing against the metal of the vertical walls of slot  34  during heavy wave action. The protective coating may eventually rub off under this wave action, causing accelerated corrosion of mesh panel  10 . 
     The inventor solved this problem by creating an alternate embodiment which has now become the preferred embodiment. FIG. 18 shows this preferred embodiment. The reader will observe that alternate back bracket  48  and alternate jacking bracket  50  are similar to back bracket  18  and jacking bracket  20 , with one important exception: the flange on each bracket which is parallel to the plane of mesh panel  10  extends toward the center of mesh panel  10  rather than away from the center of mesh panel  10  (compare particularly FIGS.  4  and  18 ). 
     FIG. 19 shows the installation of a panel assembly using alternate back bracket  48  and alternate jacking bracket  50  in slot  34  of post  32 . Using this configuration. there is no contact between mesh panel  10  and the walls of slot  34 . Thus, the abrasion damage to mesh panel  10  is largely eliminated. 
     FIG. 20 shows the same assembly from above. In this view, one may more readily observe how the flanges of alternate back bracket  48  and alternate jacking bracket  50  extending in a direction parallel to mesh panel  10  serve to prevent mesh panel  10  from bearing directly against the vertical walls of slot  34 . The other features of the two alternate brackets—such as the jacking member—are essentially identical to those features found on the original brackets. Those skilled in the art will appreciate that the fasteners used to join alternate back bracket  48  and alternate jacking bracket  50  together must lie flush with the surfaces of the brackets. Otherwise, the portions of the fasteners which protrude would prevent the device from sliding into slot  34 . 
     The method of applying the original device disclosed in FIGS. 1 through 10, or the preferred embodiment disclosed in FIGS. 18 through 20, is the same. FIG. 11 illustrates a typical shoreline. Water  44  meets the sand of the beach at low tide line  44 . Waves have not been illustrated for purposes of simplicity. However, it is important to keep in mind that waves of varying sizes will typically be approaching the beach from right to left in the view as shown. 
     A line of posts  32  is embedded in the sand as shown. These posts start to the landward of low tide line  44  and extend to seaward (to the right in the view as shown) out into the water. Several panel assemblies  38  are placed between posts  32  as described previously. Although only a single fence structure is illustrated, those skilled in the art will realize that the structure illustrated is one of a series of such structures arrayed along the beach. Each line of fencing is typically separated by 30 to 200 feet of open space. 
     As the tide comes in the series of panel assemblies  38  will become partially submerged. The mesh panel  10  within each panel assembly  38  will tend to cause sand particles suspended in the water to fall out of suspension and accumulate on the bottom. FIG. 12 shows the result of this process. The reader will observe that low tide line  44  has moved to seaward in the vicinity of the fence structure. This region is designated as accumulation zone  46 . 
     The panel assemblies  38  are free to be raised progressively with respect to the line of posts  32  as the sand accumulates. It is also possible to provide means for holding them at a fixed elevation. Practical experience has shown, however, that simply pulling the bottom edge of each panel assembly  38  free of the sand and allowing it to rest again on the sand provides an efficient method of height adjustment without resort to mechanical fixing means. Under optimum sand deposition conditions, this raising of the panel assemblies must be performed every few hours. If the raising operation is not performed regularly, then some panel assemblies  38  may become mired such that the user is incapable of lifting them free. In that case, mechanical jacking devices are applied to the jacking points on each panel assembly  38  to lift them free. 
     Those skilled in the art will realize that once sand has accumulated to the point shown in FIG. 12, the panel assembly  38  on the left hand extreme (in the view) of the line of posts can be removed and transferred to the right hand end of the line. Each panel assembly  38  is sufficiently rigid and light to be removed, carried, and reinstalled by one person under most circumstances. 
     FIG. 13 shows the same fence assembly after one panel assembly  38  has been removed from the left end of the line and added to the right end. Meanwhile, accumulation zone  46  has extended further to the right. 
     FIG. 14 shows the same fence structure after another panel assembly  38  has been transferred from left to right. At this point, the two posts  32  furthest to landward are no longer needed. Accordingly, these two posts  32  are removed and added to the seaward end of the line (to the right in the view). 
     In FIG. 15 the process has continued with the removal and transfer of another post  32  and another panel assembly  38 . The deposition process has continued to move accumulation zone  46  to seaward. The process of transferring panel assemblies  38  has continued in FIG.  16 . 
     Eventually, low tide line  44  will have been moved seaward to the desired position. The reader must keep in mind that the fence structure shown is one of numerous such structures in parallel. If left in a fixed position, the undulations in low tide line  44  tend to smooth into a uniform shoreline. FIG. 17 illustrates this result. Once the shoreline has stabilized, the entire fence structure is removed—leaving the natural beach. 
     The reader will therefore appreciate that the modularized nature of the fence structure disclosed allows a user to “walk” the structure out into the sea as the shoreline advances. In this way, the need for extended and unsightly fencing structures is eliminated. The invention has additional advantages in that it: 
     1. Does not require the deployment of pilings or support structures a considerable distance from shore; 
     2. Provides means for preventing the burial of the fence material used, 
     3. Is sufficiently rigid to resist wave forces; 
     4. Does not require the addition of large external bracket structures on the pilings, 
     5. Is modular in nature, allowing the fence structure to be “walked” to seaward as the sand accumulates; and 
     6. Transmits tensile loads placed on the mesh to the posts. 
     Although the preceding description contains significant detail, it should not be construed as limiting the scope of the invention but rather as providing illustrations of the preferred embodiment of the invention. Thus, the scope of the invention should be fixed by the following claims, rather than by the examples given.