Silt Fence System And Method Of Manufacture

A silt fence with configurable barrier sections. The silt fence comprises a plurality of posts mounted on or in the ground, a fence panel, an apron panel, and a plurality of configurable barrier sections. The fence panel is secured in a vertical position to the posts and has a fence toe adapted to be buried in the ground. The apron panel is attached to the fence panel and extends from the fence panel to rest on the ground. An apron toe is also adapted to be buried in the ground to prevent erosion. Each of the plurality of configurable barrier sections has a panel edge and an apron edge, with the panel edge attachable to the fence panel perpendicular to the length of the fence panel and the apron edge attachable to the apron panel perpendicular to the length of the apron panel. The configurable barrier sections may be flexible or removable, and may be positioned in a barrier position or a cleaning position. In the cleaning position, accumulated silt or runoff is easily cleaned from the apron panel of the fence.

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Description

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No. 60/978,999 filed Oct. 10, 2007, the contents of which are incorporated fully herein by reference.

FIELD OF THE INVENTION

The present invention is directed to the field of construction equipment and more particularly to silt fencing for soil retention.

SUMMARY OF THE INVENTION

The present invention is directed to a silt fence comprising a plurality of posts mounted on or in the ground, a fence panel, an apron panel, and a plurality of configurable barrier sections. The fence panel comprises a fence toe, wherein the fence toe is adapted to be buried in the ground. The apron panel has a back edge and an apron toe, the back edge being attached to the fence panel along a length of the fence panel and proximate the fence toe. Each of the plurality of configurable barrier sections has a panel edge and an apron edge, the panel edge attachable to the fence panel perpendicular to the length of the fence panel and the apron edge attachable to the apron panel perpendicular to the first edge of the apron panel. Further, the fence panel is adapted to be connected to the plurality of posts such that the fence panel is maintained in a substantially vertical position and the apron panel extends from the fence panel and is adapted to rest on the ground.

In an alternative embodiment, the present invention is directed to a barrier section for use with a silt fence comprising a substantially vertical fence panel. The barrier section comprises a barrier plate, a base plate, and at least one securing prong. The barrier plate is oriented substantially vertical and has a vertical edge. The base plate is secured substantially perpendicular to a bottom edge of the barrier plate. The at least one securing prong extends down from the base plate and is adapted to secure the configurable barrier section to the ground.

In yet another embodiment, the present invention is directed to a method for manufacturing a silt fence comprising a fence panel, an apron panel and a plurality of configurable barrier panels. The method comprises the steps of a) attaching a back edge of the apron panel to the fence panel proximate and parallel to a bottom edge of the fence panel, b) attaching a first edge of one of the configurable barrier panels to the apron panel and the fence panel, and c) repeating step b) for each of the plurality of the configurable barrier panels at a predetermined separation from another one of the plurality of configurable barrier panels. The attaching step a) will have defined a connection line where the apron panel is attached to the fence panel and a fence toe representing a portion of the fence panel between the connection line and the bottom edge of the fence panel. The attaching step b) will attaching the configurable barrier panel to the apron panel and the fence panel perpendicular to the connection line and from a first point proximate a front edge of the apron panel to a second point proximate a top edge of the fence panel. The attaching step b) will also have defined an apron toe representing a portion of the apron panel between the first points and the front edge of the apron panel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a silt fence built in accordance with the present invention.

FIG. 2A is a cut-away perspective view of the silt fence of FIG. 1 showing the configurable barrier section in the barrier position.

FIG. 2B is a cut-away perspective view of the silt fence of FIG. 1 showing the configurable barrier section in the cleaning position

FIG. 3 is an alternative embodiment for a silt fence using removable barrier sections.

FIG. 4 is a perspective view of a post for use with the silt fence.

FIG. 5 is a perspective view of an alternative post for use with the silt fence.

FIG. 6 is a perspective view of another alternative post for use with the silt fence.

FIG. 7 is an end cross-section view of the fence panel and apron panel of the silt fence during manufacture.

FIG. 8 is a perspective view of the fence panel and apron panel from FIG. 7 after attachment.

FIG. 9 is a perspective view of the fence panel and apron panel from FIG. 7 with a barrier section attached.

FIG. 10 is a perspective view of silt fence cleaning machine for use with the silt fence of FIG. 1.

BACKGROUND OF THE INVENTION

Silt fences are often used on construction sites or the like to prevent sediment runoff from leaving the site and entering natural drainage way or storm drainage systems. The fence operates to slow storm water runoff and causes the deposition of sediment along the fence. Silt fencing encourages sheet flow and reduces the potential for development of rills and gullies. The basic design of silt fencing has changed little since it was introduced nearly a century ago.

Ideally, the standard silt fence, excluding approximately 10 feet on each end, is installed along the contour lines of the job site. The end sections may be turned slightly uphill. The goal is to form a slow draining catch field for the water-silt mixture (runoff that forms during a rainfall event (i.e., time is given for the silt to settle out of the runoff). In practical terms, rarely is the silt fence installed on the contour, either because of cost or because of the desire to install the fence along the boundary of the work site. However it is installed, problems often occur even in minor rainfall events.

A first problem is that the weight and momentum of the runoff over stresses the fence and posts along the fence, which can fail the fence by physically knocking the fence down. The result is that the silt fence fails and allows the runoff to flow over the silt fence resulting in contaminated water flowing downstream in the water shed. A second problem occurs when the runoff flows to the fence, and then begins to flow along the fence. This parallel flow along the fence tends to result in erosion near the toe of the fence washing out the back fill which frees the bottom of the silt fence allowing water to freely flow under the fence. As before, the result is that the silt fence fails and contaminated water continues to flow downstream. Another problem can arise where the soil may build up along the silt fence or at particular points such that the deposited sediment blocks a substantial portion of the fence making the fence ineffective in trapping additional soil. Therefore, periodic cleaning of the fence to remove this accumulated soil is required to maintain effective functioning of the fence. The various inventions contained in this disclosure are intended to address various aspects of these failure mechanisms. These inventions greatly minimize these problems and have a number of additional advantages.

As will be discussed in more detail below, the silt fence of the present invention is composed of a fence panel, an apron panel, and multiple configurable flow barriers spaced periodically along the fence. The flow barriers are attached to the apron along the bottom and the fence along the side producing a fence with a plurality of barriers perpendicular to the fence panel. In this configuration, water with eroded soil (runoff) will accumulate or pond on the uphill side of each flow barrier. This ponding effect provides time for the water to filter through the fence. As the water filters through the fence the majority of the eroded soil will be filtered from the water and remain just uphill of each barrier. These and other features to be discussed provide a substantial improvement over standard fence.

DETAILED DESCRIPTION OF THE INVENTION

With reference now to the drawings in general and to FIG. 1 in particular, there is shown therein a silt fence 10 with configurable barriers built in accordance with the present invention. The fence 10 is comprised of a filter fence panel 12, an apron panel 14, and a plurality of configurable barrier sections 16. The filter fence panel 12 is a substantially vertical section and is in many respects similar to a vertical standard silt fence. The apron panel 14 is a substantially horizontal section allowed to lie on the ground surface. The plurality of configurable barrier sections 16 are panels movable between a barrier position 18 and a cleaning position 20 (shown in FIG. 2B). In the barrier position 18, the barrier sections 16 block water flow along the fence 10. In the cleaning position 20 the barrier section 16 panel lies down or unfolds flat against the apron panel 14 and the fence panel 12 to allow improved cleaning.

The configurable barrier sections 16 allow the present invention to be installed across contour lines and retard flow in two directions. This design gives the effectiveness of having many small silt fences installed across the contour of the ground, but the installation ease of having one continuous silt fence with significantly improved manufacturing and cleaning capability while the apron reduces the risk of toe erosion.

The filter fence panel 12 is preferably made of a water permeable material and held in place using a plurality of posts 22 mounted on or in the ground. The posts 22 shown in FIG. 1 are traditional stakes driven into the ground at various intervals, though various alternatives for posts will be anticipated and discussed further below. The posts 22 function to maintain the fence panel 12 in a substantially vertical position. The fence panel 12 comprises a top edge 24 and a bottom edge 26, generally parallel to each other, and is characterized by a length. A fence toe 28, adjacent the bottom edge 26 of the fence panel 12, represents a portion of the fence panel that is buried in the ground during installation. Burying the fence toe 28 provides for additional stability of the fence panel 12 and the silt fence 10 in general.

The apron panel 14 is a horizontal section that runs along and over the ground. The apron panel 14 is also made of a water permeable material, though its permeability may be less than that of the fence panel 12 to minimize erosion beneath the apron panel. The apron panel 14 comprises a back edge 30 and a front edge 32, generally parallel to each other, and is characterized by a length. The back edge 30 of the apron panel 14 is attached to the fence panel 12 proximate the bottom edge 26 of the fence panel and adjacent the fence toe 28. The apron panel 14 is attached in this manner, a sufficient distance from the bottom edge 26, to allow the fence toe 28 to be buried in the ground during installation as mentioned above. The apron panel 14 then extends from the fence panel 12 so that it may rest on the ground surface. The apron panel 14 and the fence panel 12 are thus maintained substantially perpendicular to each other. The front edge 32 of the apron panel 14 comprises an apron toe 34 that is buried in the ground. The apron toe 34 will greatly minimize the possibility of runoff underflow problems along the fence 10, because water will flow onto the apron 14 before it begins to flow parallel to the fence.

In many situations, burying the fence toe 28 and the apron toe 34 may be difficult. Preferably, the fence toe 28 will be buried as shown in FIG. 1, though alternative profiles may work as well. Burying the toe 28 may be done by a vibratory plow in one pass or with a trencher and subsequent backfilling. Methods applicable to installing the silt fence 10 of the present invention using a vibratory plow or trencher are disclosed in an application titled Silt Fence Installation Assembly (PCT/US2007/012957, Jun. 10, 2007), the contents of which are incorporated herein by reference.

Alternatives to burying the fence toe 28 and the apron toe 34 are contemplated. For example, short stakes at predetermined intervals may be used to pin the fence toe 28 or apron toe 34 to the ground. In high wind situations where the stakes are insufficient to hold down the silt fence 10 between stakes 22, a stiffening member could be located along an edge of the toes 28 and 34. Another option for a stiffening member is a permanently attached rope which is stretched between stakes. Other types of stiffening members could be used in place of the rope such as placing a low cost board or other like acting material along the edge of the toe 28 or 34. Use of a board would tie down or prevent the toe 28 or 34 from blowing up in a windy condition.

A further alternative for securing the fence 28 toe is to have a second tail (not shown) that is generally left on the soil surface of the fence toe during installation of the apron toe 34. Then in a second operation, an installation crew would move along the fence 10 and cover the tail with a shallow mound of soil to prevent wind from getting under the apron panel 14 from the fence toe 28. One skilled in the art would also realize that a combination of each of several of these alternatives could be used to improve holding down the silt fence 10.

With continued reference to FIG. 1, the configurable barrier section 16 is shown with the barrier restricting water flow parallel to the length of the fence panel 12. Each of the barrier sections 16 is substantially vertical and perpendicular to the fence panel 12, and is adapted to allow water to pass through while trapping soil and sediment. The barrier section 16 comprises a fence edge 36 and an apron edge 38. The fence edge 36 is attachable to the fence panel 12 perpendicular to the back edge 26 and the length of the fence panel. The apron edge 38 is attachable to the apron panel 14 perpendicular to the length of the apron panel.

Referring now to FIG. 2, one of the plurality of barrier sections 16 is shown in more detail. In this embodiment, the barrier section 16 is comprised of a flexible fence material permeable to water flow but able to filter fine particles of a particular size from the water. The material forms a barrier panel 40 that is configured to be movable between a barrier position 18 and a cleaning position 20. In the barrier position 18, shown in FIG. 2A, the barrier panel 40 is substantially vertical and functions to restrict flow of soil or sediment. In the cleaning position 20, shown in FIG. 2B, a portion 42 of the flexible barrier panel 40 lies flat against the apron panel 14. With the barrier panel 40 in the cleaning position 20, sediment 44 that had collected against the fence panel and the barrier panel can be removed to prevent an excess of sediment that may cause the silt fence to fail.

The barrier panel 40 shown in the embodiment of FIG. 2 is substantially trapezoidal in shape. In this embodiment, the fence edge 36 and the apron edge 38 comprise a first base side 46 of the trapezoidal panel 40. The fence edge 36 and the apron edge 38 are secured to the fence panel 12 and the apron panel 14 respectively. A second base side 48 of the trapezoid opposite the first base side 46 of the trapezoidal panel 40 comprises an attachment site 50. The attachment site 50 allows the second base side 48 of the barrier panel 40 to be removably secured to one of the plurality of posts 22 when the barrier panel is in the barrier position 18 (FIG. 2A). Preferably, the attachment site 50 comprises an eyelet or grommet 52 with a reinforced panel section 54. More preferably, a tie (not shown) may be used to secure the eyelet 52 to the post 22. The tie may comprise a string, a velcro strip, a plastic tie, a wire, a ring, or other component used to secure the eyelet 52 to the post 22.

Alternatively, the attachment site 50 may comprise a draw string (not shown) for securing the attachment site to the post 22. In this alternative embodiment, the second base side 48 of the trapezoidal barrier panel 40 comprises a hem to form a pocket for a draw string or other tie. The hem is preferably formed by creating a fold in the barrier panel 40 parallel to the second base side 48 and securing the second base side to the barrier panel. The draw string or other tie is passed through the hemmed pocket and used to secure the attachment site 50 to the post 22.

Alternative shapes for the barrier panel 40 are contemplated. For example, the barrier panel 40 could take the form of an isosceles triangle. In such a case the base of the triangle would again comprise the apron edge 38 and the fence edge 36, to be attached to the apron panel 14 and the fence panel 12 respectively. A vertex of the panel 40 opposite the base would comprise the attachment site 50. The attachment site 50 would preferably comprise a grommet for use with a tie to secure the barrier panel to the post. The isosceles triangle shape would function similar to the trapezoidal shape discussed previously, while reducing the material needed for the barrier panel 40 and limiting the flap 56 of material when the barrier panel is in the barrier position.

Yet another alternative shape for the barrier panel 40 comprises a right triangle with a base of the triangle secured to the apron panel 14 and the attachment site 50 comprising a grommet at the vertex opposite the base attached to the apron panel. In such a case the barrier panel 40 would have no permanent attachment to fence panel 12. Once the silt fence 10 is installed in the ground and attached to the posts 22, the barrier panel 40 is be raised into place and attached to one of the posts. The attachment site 50 preferably comprises the grommet as discussed previously. Alternatively, the attachment site 50 may comprise an attachment tab. The attachment tab may consist of a reinforced section defining a pocket for receiving the post. The pocket may be slid on top of the post for holding the barrier panel in the barrier position.

Referring now to FIG. 3, there is shown therein an alternative embodiment for a configurable barrier section 16 of the silt fence 10. In the alternative embodiment the barrier section 16 comprises a rigid support 60. The rigid support 60 for the barrier section 16 comprises a vertical barrier plate 62 and a base plate 64 secured substantially perpendicular to a bottom edge 66 of the barrier plate. The barrier plate 62 further comprises a vertical edge 68. The vertical edge 68 defines the panel edge 36 of the configurable barrier section 16. Preferably, the barrier plate 62 further comprises a plurality of receiving slots 70 along the vertical edge 68 of the barrier plate. The receiving slots 70 are adapted to connect the barrier plate 62 to one of the plurality of posts 22 of the silt fence 10, as will be described below.

Preferably, the barrier plate 62 defines a plurality of slots 72 proximate the base plate 64. The slots 72 function to allow water to pass through the barrier plate 62, while the flow of soil runoff past or through the barrier plate is retarded. As an alternative or in addition to the plurality of slots 72, the barrier plate 62 may define a pass through opening 74 to which a removable and water permeable bag or catch basin (not shown) could be attached. As the bag becomes filled with soil runoff, the bag can be removed and emptied before the silt fence 10 fails. The use of such a bag provides an alternative for the cleaning feature of the configurable barrier 16.

The base plate 64 defines the apron edge 38 of the configurable barrier section 16. The base plate 64 is preferably designed to allow the barrier plate 62 to stand vertically with the base plate on the ground. More preferably, the base plate 64 comprises at least one securing prong 76 extending down from the base plate. The at least one prong 76 is adapted to secure or attach the configurable barrier section 16 to the apron panel 14. The prong 76 will preferably be used to pass through the material of the apron panel 14 and into the ground, securing the position of the barrier panel 16.

Continuing with reference to FIG. 3, there is also shown therein an alternative embodiment for the posts 80 of the silt fence 10. The silt fence 10 requires support along its length to hold up the silt fence and resist wind and water loads. One of the major complaints from silt fence installers is that installing the traditional posts is very labor intensive. This is especially true in gravely or hard rock conditions. The posts 80 shown in the embodiment of FIG. 3 are mounted on the ground and do not need to be driven in the ground. Preferably, the post would be substantially similar in design to the rigid barrier 60 section described above. The post 80 comprises a post plate 82 and a post base 84 secured substantially perpendicular to a bottom edge 86 of the post plate. Preferably, the post base 84 is configured to rest on the ground and support the post plate 82 in a substantially vertical position. The post base 84 may comprise one or more soil prongs 88, or accommodations for the same, to provide additional stability for the post 80.

The post plate 82 comprises a vertical edge 90 that is provided to support the fence panel 12 of the silt fence 10. Preferably, the vertical edge 90 of the post plate 82 will comprise a plurality of securing hooks 92. The securing hooks 92 allow for the material of the fence panel 12 to be secured to the post 80. The hooks 92 also provide for the barrier plate 40 of the configurable barrier section 16 to be secured to the post 80. One skilled in the art will appreciate the present embodiment allows for the barrier plate 40 to be disengaged from the post 80 and removed temporarily to allow for cleaning of the silt fence 10.

Other alternatives for posts 80 mounted on the ground and not needing to be driven in the ground are anticipated. For example, alternative stakeless posts include: the use of “L” stands weighted with sandbags or small spikes; tripod legs for post stands; and stiff members (e.g., wire, composite, wood) bonded to the fence and held vertical using tension members (e.g., guide wires, cables, ropes).

In addition to the varied stakeless post options, the present invention contemplates alternative structure for posts 22 secured in the ground that would support the fence panel 12. As stated previously, one of the major complaints from silt fence installers is that installing the posts is very labor intensive. The process typically involves stapling, nailing and/or screwing the silt fence 10 fabric to the post. With reference now to FIG. 4, there is shown therein is an alternative post 100 design for use with the silt fence 10 that contemplates a quick attach method for securing the fence panel 12. The post 100 comprises a stake body 102 preferably made of steel or other rigid material. As shown, the stake body 102 has a contoured cross-section for added strength. The post 100 further comprises an elongate tab 104 having at least one fence hook 106. The tab 104 is attached at an upper end 108 to the stake body 102. The tab 104 defines a tongued slot adapted to receive a portion of the fence panel 12. The fence panel 12 can be slid into the tongued slot between the tab 104 and the stake body 102 at a bottom end 10 of the tab. The fence hook 106 is preferably directed upward and is used to grab the fence panel 12 when the fence panel is slid into the tongued slot, further holding the fence panel in a vertical position.

Turning now to FIG. 5, an alternative design for the post 112 may comprise a two-piece structure for securing the fence panel 12. The post 112 of this embodiment comprises a first stake member 114 and shorter second member 116 that have corresponding mating geometric cross sections. The first stake member 114 is driven into the ground as with a traditional stake post 22. The fence panel 12 is held across the geometric cross section of the first member 114. The second member 116 is then seated against the first member 114 such that the fence panel 12 is pinched between the two members, holding the fence panel in a vertical position. To provide additional holding strength, the first member 114 and the second member 116 may also comprise mating hooks 118 or tabs and slots 120 similar to the fence hooks described previously. The hooks 118 or tabs may pierce through the fence panel 12 or press the fence panel through the corresponding slot 120 to hold the fence panel in place.

Yet another alternative embodiment for posts 122 for the silt fence 10 is shown in FIG. 6. As shown in this embodiment, the post 122 again comprises a first stake member 124 and has a predetermined geometric cross section and at least one slotted eye 126. The first stake member 124 is driven into the ground as with a traditional stake post 122. A second member 128, shaped similar to a hairpin cotter pin, comprises at least one protrusion and is designed to slide over a top exposed end 130 of the first member 124. With the fence panel 12 held across the geometric cross section of the first member 124, the second member 128 is then pushed over the first member such that the fence panel is pinched between the two members, holding the fence panel in a vertical position. The spring tension of the second member 128, created when the second member is positioned over the first member 124 causes the protrusion on the second member to push a local section of fence panel 12 through slotted eye 126 on the first member. The first member 124 and the second member 128 are now locked in place and the fence panel 12 is secured in a vertical position.

Another aspect of the present invention contemplates the manufacture of the silt fence 10 as described with regard the embodiment of FIG. 1. As described there, the silt fence 10 is typically made up of three individual components. These comprise the fence panel 12 (vertical component), the apron panel 14 (horizontal component), and the configurable barrier section 16. Production of the raw material or fence cloth to produce the components would typically be done in a first step of production. Typically the silt fence 10 components are made from a woven material commonly referred to as a geotextile, though other materials could be used for certain components or sub-components. Alternatively, sheets of homogeneous material that have been needle punched can be substituted. For purposes of this invention any number of substitute materials may be used without limiting the scope of the invention. The woven material can be from numerous raw materials but is commonly polypropylene.

The fence panel 12 raw material would typically be purchased in bulk rolls. In most respects it would be similar to any common silt fence 10 material in that it would be permeable to water flow but able to filter fine particles of a particular size from the water. However it would preferably be a premium version of fence material as is commonly available on the market today. It would preferably be purchased in large rolls of greater than several thousand feet in each roll and may be already cut to the proper widths.

The apron panel 14 could be made from similar raw material as the fence panel 12, but would preferably be made to be much less permeable material to water flow. The apron panel 14 is preferably cut and handled in a similar way as the fence panel 12. The apron panel 14 would typically be purchased already cut to the desired width and in large rolls of several thousand feet.

The configurable barrier section 16 raw material would typically be similar to the fence panel 12 material, or could be made from a third material with different properties such as permeability, strength, weight, etc. Note that in some instances, one could envision different materials being used depending on the requirements of the job for which it will be applied or for marketing purposes where a premium fence might use more costly raw materials than a more economical fence. These differences would likely be reflected in performance and the needs of the particular application.

Fence panel 12 material, apron panel 14 material and barrier section 16 material may be selected to optimize their properties for a specific intended application or job and may be similar or dissimilar depending on said application. Said selection could be done by Engineering Specification (described below) for a specific customer and application. For the purposes of this discussion, they are assumed to be of a woven material similar in configuration to standard silt fence material but may be made from different thickness fabric or woven in a tighter weave to increase filtering. From testing it has been found that mixing different materials can improve the efficiency of the silt fence 10.

Engineering Specification can be defined as an engineering analysis to specifically specify selection of component materials based on the engineered analysis for final use of the product. For example, in certain soils one type of material may produce a superior filtering result over another material. In certain cases, the material may be treated with chemicals, such as a flocculent, to help create the conditions where very fine particles such as clays tend to clump together and separate. In a separate example, in an area of the country with very high rainfall, one might determine to include reinforcing strips and select a different specific material. A third example might be a difference in requirement by a governing body or the critical nature of the installation site. A fourth specification might be to specify a different spacing between the configurable barrier sections. A computer program, selection chart, or other type of engineering specification could be used to help in selection and specific manufacturing recommendations. However the materials are selected and specified, the remainder of this disclosure is similar.

Preferably, the fence panel 12 and the apron panel 14 would be purchased already cut to the correct width and typically be approximately 36 inches and 48 inches wide, respectfully. As described above, the final dimensions could he selected based upon specific needs of the final installation. The width referred to is the height in FIG. 1 for the fence panel 12 and would include the portion described as the fence toe 28. Additionally, the apron panel 14 width is the horizontal section of the apron, including the portion described as the apron toe 34. In cases where cost or availability is limited, or because of needs for a different width, the silt fence 10 components may need to be cut to a specific dimension of width, or sewn or made up of multiple components. Cutting of the material would typically be done with a “hot knife” to prevent the edges from fraying after they are cut. Though other means such as scissors or rotary cutters or band saws are capable of cutting the silt fence 10 materials, the cutting process would then sometimes be followed by a process to produce a seam along the edge to prevent fraying. Preferably the edges involved in a seam would not require their edges to be sealed to prevent fraying; fraying of the edges would be reduced by the process of attaching them to their counterpart during assembly to produce an attachment seam.

The barrier sections 16 would typically be produced by cutting the basic shapes from the raw material. Said cutting device could be a hot knife or other device as referenced earlier. Alternatively the barrier sections 16 could be cut in bulk from a multi-layer stack of raw material using a laser or water jet to cut out the basic shape. Alternatively a roIling die type cutter could be used to stamp out barrier sections 16 one at a time or from a stack of material or a continuously moving single layer of material. Then the edges of each piece could be treated if necessary to prevent fraying. However, the edge or edges that will subsequently be involved in a seam would not necessarily require sealing. If a cut edge is used instead of a fold, then this edge will require sealing to prevent fraying. This sealing could entail folding over an edge and then sewing or bonding with glue and/or heat along said edge lengthwise, or quickly melting the edge with heat.

The fence panel 12 and barrier sections 16 are typically made from material that is relatively elastic. In some cases the fence panel 12 and barrier section 16 material might require the addition of reinforcing strips (not shown). These strips reduce stretching of the material in strategic locations. The reinforcing strips could include a single strip of non-elastic fabric typically less than 1 inch in width and fastened continuously along the top edge of the fence panel or barrier sections. In some situations, additional reinforcing strips can be added to the fence panel 12 at specific heights along the fence. In extreme situations, the fence panel 12 or barrier sections 16 could include a cross hatch of reinforcing strips or threads. These reinforcing strips may be included as part of the original silt fence 10 raw material during its manufacture. This would typically be done as part of the weaving process. Alternatively, this could be added in a subsequent step at a later stage of manufacturing. If added in a subsequent step, the reinforcement strips may be attached by numerous means depending on the physical characteristics of the strips and the fence. Preferably, the reinforcing strips would be sewn on the fence 10 components, but those skilled in the art understand that they could be attached to the material by heat fusion or by gluing. Regardless of the means of attaching the reinforcing strips, their purpose is to add strength to the fence panel or barrier sections when necessary. Differing types of reinforcing strip material or quantity of material could be added depending on the engineering specification of the fence.

Common in the standard silt fence industry is the use of wire as a backing material. An alternative to the cloth type reinforcing strips discussed above, a wire cloth as it is referred to in the industry might be added to the fence panel 10 during manufacturing or added in a subsequent step. The wire cloth could be permanently attached to the fence panel 12 or attached to the fence by gluing or attaching in specific locations. More preferably, if a wire cloth is required it could simply be added as the final silt fence 10 is rolled into a final roll. This will be described in more detail later. If wire is added to the silt fence 10, then that would obviously require modifications to the installation device and manufacturing of the fence.

Manufacturing Steps: To effectively produce the silt fence 10 of the present invention, an efficient process needs to be developed to manufacture the silt fence fabric assembly. The following list highlights the required operational requirements of the finished fabric assembly.

    • 1) Since the fence is best installed with a double blade vibratory plow, the fabric assembly should be manufactured as a spooled product.
    • 2) Preferably, the as installed silt fence would need no further setup other than to unfold the fence and install the support posts.

Step 1—Manufacture the FFA: Connecting the apron panel 14 to the fence panel 12 (thus producing a Filter Fence and Apron assembly termed FFA) is typically accomplished by bringing the two materials together on a specific production line to produce a longitudinal seam 200 between the materials as shown in FIG. 7. The FFA longitudinal seam 200 may be produced by sewing, gluing, heat fusion, or by continuously attaching by some permanent method the apron panel to the fence panel.

Large rolls of apron panel material and fence panel material are first installed on feed supply rollers (not shown) adjacent an assembly line. These feed rollers would typically be in close proximity to each other. The roll may be powered to facilitate unrolling and controlling the large and often heavy rolls of raw material. The speed of unrolling may be controlled to produce a specific velocity in say feet per minute. The unroll speed whether powered or un-powered is generally matched between the apron material and fence material. The unroll speed is also generally matched to the speed of the seaming device. This is designed to match the average speed of the FFA assembly line. In the preferred method, a braking device would typically provide proper tension to the material and prevent backlash on the roll. Additionally a material storage loop resembling a “S” shape may be used to maintain tension in the fabric and account for small variation in supply speed. A feedback mechanism may monitor the tension and position of the storage loop to provide feedback and adjust speed of the supply reels and the FFA assembly line speed. Said feedback mechanism could be mechanical or electrical or a combination thereof.

As the two materials are fed into the manufacturing line, the back edge 30 of the apron panel 14 is closely positioned to the seaming location on the fence panel 12. Then the longitudinal seam 200 is produced as described above to produce the FFA assembly shown in FIG. 8.

Step 2—Attach the Barrier Sections to the FFA: Referring now to FIG. 9, shown there is the desired configurable barrier section 16—FFA orientation and location for attachment of the barrier section to the FFA along an attachment line 202. Optional attachment of a top edge 204 of the flow barrier 16 and fence panel 12 together, and along an angled fold line 206 may improve operation of the fence 10 as discussed above.

Attaching the barrier section 16 to the apron side 14 of the FFA and the fence side 12 of the FFA could be accomplished in one operation or each side could be fastened in separate operations. In separate operations, care and possibly an additional step may be required to prevent leaving a small section un-attached where the two seams meet. Typically the spacing of the barrier 16 along the fence panel 12 would be every ten feet. However, these methods could be used to vary barrier 16 spacing distance along the fence panel 12 per engineering specification from the customer or design engineer.

It is preferable that the manufacturing line operates as a continuous process, but the following concepts are also applicable to a discrete process where the line pauses to complete a step before continuing. A discrete process may also allow for better human intervention and labor.

Preferably, the FFA material could be delivered to the manufacturing line on a reel. Typically, as describe in Step 1 above, the FFA would be produced in a separate previous step to the attachment of the barrier sections 16. The preferred method of attachment of the barrier sections 16 to the FFA is by a hot wedge adhesion machine which utilizes a wedged shaped heating device which slightly melts the two surfaces and subsequently bonds them together by pressure. The barrier section 16 would be put in position (FIG. 9) by hand or by use of a mechanical positioner such as a robot or automated location mechanism. In a continuous moving process, the seaming device would match the forward travel speed of the barrier 16 and moving FFA material. Once a seam was produced it would quickly transition back to the start of next barrier section position 16 and again match FFA speed. Once the barrier section 16 is in place relative to the FFA, the hot wedge would move generally perpendicular from one edge and quickly pass between the barrier section 16 and FFA at the specified speed range for optimum adhesive strength. Following directly behind the hot wedge and typically moving in concert with it, one or more press rollers apply pressure to firmly press the melted surfaces together directly behind the wedge to bond them together and produce the desired seam. At that point, it is allowed to cool as necessary and the line advances to the next periodic position along the FFA for installation of the next barrier section 16.

An alternative method for manufacture includes a moving arm which would be positioned to deposit a line of adhesive at the desired attachment line on the FFA. Typically said adhesive would be hot glue that melts and flows while hot, but as it cools it produces a solid bond between the barrier section and the FFA. Though other adhesives could be used as well and may be preferable depending on the materials used. Quickly after deposition of the glue, a mechanical arm with an attachment frame picks up a single pre-cut barrier section or other type barrier sections and positions it over the line of glue on the FFA. In some instances, glue may also be applied to barrier edge. Pressure would be applied to the seam between the barrier section and the FFA until the glue had sufficiently cooled to bond the materials together. With other glues: time, light or some type of catalyst may be necessary to provide bonding.

Supply of the barrier sections 16 individual pieces could be by pre-cut pieces or a mechanical device. The mechanical device may include a system which can unspool a predetermined quantity of material cut to the desired barrier section shape from a bulk roll then supply the cut piece to the assembly area. This would be done before attaching the materials to the FFA.

For the barrier section 16 design of the present invention, one advantage is the material edge may be attached to the FFA assembly and then cut from the bulk spool rather than supplied as precut pieces. In such a case, a mechanical device would unspool barrier material and position it relative to the FFA at the desire attachment location. The edge section of material can then be secured on the attachment line. Adhesion could be by glue or hot wedge or other means. Once the attachment seam is complete, a cutting device would cut the proper amount of material from the barrier section material spool and the process would repeat.

It should be obvious to one skilled in the art, that other types of gluing, sewing, thermal bonding, riveting, and/or stapling or any combination there of can be used to attached the barrier sections 16 to the FFA. It should also be obvious to one skilled in the art that the design of the mechanical device necessary for positioning and fastening the barrier sections could include:

    • 1) a moveable base robotic arm that could pickup a single barrier section (or unspool and cut from a roll), accurately position the barrier section onto the FFA, and install the dam via a fastening system; and/or
    • 2) a fixed base longitudinal conveyor where a barrier section handling fixture would move parallel to the position on the FFA that the barrier section is to be fastened to.

Step 3—Spool the Assembled Silt Fence on Storage Rolls: After the barrier section 16 is attached, the barrier is urged to lay flat against the FFA. Then the fence panel 12 is typically folded on top of the apron panel 14 with the barrier section 16 in-between the fence panel and the apron panel. The end result is a mostly flat assembly as shown in FIG. 7. The flattened assembly is then tightly rolled onto a storage roll.

The finished silt fence 10 assembly must be oriented to have as few folds as possible before it is spooled on the reel. It is important to note that orientation of the seam 200 between the fence panel 12 and the apron panel 14 will have an impact on the spooled thickness. Therefore, care should be taken when deciding how to attach the fence to the apron. One possible orientation for the seam 200 is shown in FIG. 7.

By reviewing FIG. 7, one can note that the fence toe 28 (right side) and apron toe 34 (left side) extend beyond the folded portions of the assembly. Also not shown in FIG. 7 is the barrier section 16 which would be folded flat and contained between the fence panel 12 and the apron panel 14 portions of the assembly. The finished flat assembly is rolled onto bulk rolls of many thousands of feet or onto small rolls for sale to customer.

Step 4—Finished Salable Rolls of finished Silt Fence for Sale to Customer: The end customer will utilize rolls of silt fence 10 in convenient size packages. Typically said packages would be approximately 1000 to 1500 feet but of a weight to facilitate manual handling of the rolls and to limit the impact of roll weight on the installation machine. Typically the finished roll will utilize a cardboard tube to support and start the roll and maintain an open central tube to facilitate placement onto a support rod on the installation machine. Thus the large storage rolls mentioned previously must be un-rolled and re-rolled into smaller finished rolls ready for installation by the dual vibratory plow.

A critical aspect of this silt fence 10 installation is the required match between direction of travel and the slope of the ground while installing fence using the dual plow installation machine on the jobsite and the un-wind direction of the roll of fence material. Thus there are left hand fence and right hand fence rolls allowing corresponding directions of travel relating to direction of slope. For proper installation two conditions must be met: first, the rolls of fence material must un-wind such that the fence panel 12 is installed on top of the apron panel 14; and second, the fence toe 28 is installed at the desired orientation relative to the jobsite. The orientation of the fence toe 28 for perimeter control generally requires the fence toe be oriented toward the outside of the jobsite or towards the boundary of the jobsite relative to the apron toe 34. In all other situations the fence 10 is to be installed such that the fence toe 28 is generally downstream or downhill for the majority of prevailing water flow on the jobsite. Thus, if one envisions a particular jobsite, for any given direction of installation travel, there is a matching roll of fence material.

Another critical element that must exist on the finished roll, is that regardless of roll direction, when the finished fence 10 is rolled onto the tube, the apron toe 34 and fence toe 28 of the flat assembly must extend beyond the edges of the overlapping fence panel 12 and apron panel 14 to facilitate installation on the jobsite by the dual plow. From a manufacturing standpoint, the large storage rolls as created in step 3 above would typically be loaded on a device for unrolling to allow the fence to be cut into smaller desired lengths and then re-rolled for customer use. These small rolls may carry a marker to indicate proper direction for loading onto the installation machine.

Care in rolling is critical because the folded assembly in the area of the barrier section increases the stack up depth of the silt fence 10 in the middle of the spooled assembly as compared to the edges. This creates the situation where finished and spooled silt fence 10 roll near the edges (the fence toe 28 and the apron toe 34) has less material and thus is much “softer” than the tightly spooled middle portion of the silt fence roll. This may create difficulties with the installation of the silt fence 10 in the field. A solution to this problem is to increase the thickness of the edges of the finished saleable spool. One way to accomplish this is to insert or add a low cost spacer (e.g., a biodegradable paper product) along the edges of the roll during the spooling process. This creates a waste product but is easily disposed of during installation. Alternatively, the paper could be attached near the areas of the fence toe 28 and the apron toe 34 for added thickness. Another method is to create small folds locally near the toe edges such that the folded edge thickness when rolled up is approximately equal to the rolled thickness of the middle section of the finished spooled silt fence 10. One could envision a design of the installation machine that would un-fold portions of the apron toe 34 and fence toe 28 during installation and would require an additional system on the installation device to unfold the edges directly prior to installation.

Cleaning Process: When the silt fence 10 (FIG. 1) requires cleaning, the configurable barrier sections 16 are unfastened and laid flat against the apron panel 14. A person not shown would manually walk or travel along the fence and unfasten or untie the barrier sections 16 from each support post 22. The person would also typically ensure that the barrier sections 16 lie down smoothly against the apron 22.

Then the silt fence 10 is then cleaned by removing any accumulated silt. One method for cleaning entails using a broom, shovel and wheel barrow (not shown) to dislodge, pickup and transport the accumulated silt. Though this process is effective, it is very labor intensive. A second method would use a specially designed scoop as part of a small front end loader; the process would include traveling mostly perpendicularly to the silt fence with the scoop on top of the apron. The action would scoop up a portion of the accumulated silt as it moves forward, but care must be exercised to not damage the silt fence in the cleaning process. A third approach is to use a vacuum to directly remove the silt. A person by hand or by controlling a vacuum boom would direct the entrance to the vacuum tube near the spoils pile. By moving the vacuum back and forth the spoils would be broken up and then sucked up by the force of the vacuum and moving air. All of these may be effective in certain situations, but each is labor intensive and thus expensive.

A preferred method of cleaning the fence 10 by removing the accumulated silt would utilize a specialty build cleaning machine 210 such as that shown in FIG. 10. This machine would be designed to clean a fence 10 with a mostly vertical section such as the fence panel 12 and a horizontal section such as the apron panel 14. The unit 210 would preferably include a powered conveyor brush or sweeper assembly 212 in combination with a vacuum pick up system 214 including a storage tank 216. The typical process would include driving carefully along the length of the silt fence 10 at each area of silt buildup 44. The operator or an automatic control system would position the brushes and conveyor assembly 212 such that they work along the silt fence 10. Once the storage tank 216 was full, the unit 210 would be driven to a dump site and the tank would be emptied.

The unit 210 shown in FIG. 10 comprises a power unit 218, the brush assembly 212, and the vacuum unit 214. The power unit 218 comprises an engine to propel the unit 210 along and provide power to various components. The brush assembly 212 comprises powered cleaning brushes 220 and powered transportation brushes 222. The cleaning brushes 220 clean the area at or near the intersection of the fence panel 12 and the apron panel 14. A corner brush would ensure good cleaning along the corner between the fence panel 12 and the apron panel 14. The set of transportation brushes 222 act like a conveyor moving silt 44 from the corner to the vacuum unit 214. The transportation brushes 222 would clean and transport the silt 44 to the area still on but near the edge of the apron panel 14. The vacuum unit 214 would pick up material. The vacuum unit 214 would use vacuum force and moving air to move the spoils to a storage tank 216 carried proximate the power unit 222.

Another alternative would include one or more vacuum entrances located above or in front of the corner brush and conveyor. These would improve cleaning by not allowing the brush to miss or drop spoils as it moves them to the vacuum. Alternatively, a storage bin may be used to replace the vacuum pickup. The bin would travel along the edge of the apron and receive the material from the conveyor brush. As the bin is filled it would be transported to a dump site and then cleaning would resume.

Certain compositions of silt may dry very hard and may not be easily swept or brushed off the silt fence 10. In this situation a specialty designed device which is capable of breaking up the spoils is needed. Specifically a conditioner may consist of pneumatic and/or water jets or a low impact mechanical action such as a rolling grinder/crusher. In case of pneumatic and/or water jets, the jets impinge on the dried soil to dislodge and break up the soil mass to ready it for conveying by the conveyor brush. In the case of the rolling grinder/crusher, this is basically a series of rollers whose edge configuration and movement tends to dislodge and break up the soil mass. But said breakup is low impact to prevent damage to the underlying silt fence material. In some situations, adding vibration to the rollers may improve their action.

Various modifications can be made in the design and operation of the present invention without departing from the spirit thereof. Thus, while the principal preferred construction and methods of manufacture and use of the invention have been explained in what is now considered to represent its best embodiments, it should be understood that the invention may be practiced otherwise than as specifically illustrated and described.

Claims

1. A silt fence comprising:

a plurality of posts mounted on or in the ground;
a fence panel comprising a fence toe, the fence toe adapted to be buried in the ground;
an apron panel having a back edge and an apron toe, the back edge attached to the fence panel along a length of the fence panel proximate the fence toe; and
a plurality of configurable barrier sections, each section having a panel edge and an apron edge, the panel edge attachable to the fence panel perpendicular to the length of the fence panel and the apron edge attachable to the apron panel perpendicular to the first edge of the apron panel;
wherein the fence panel is adapted to be connected to the plurality of posts such that the fence panel is maintained in a substantially vertical position; and
wherein the apron panel extends from the fence panel and is adapted to rest on the ground.

2. The silt fence of claim 1 wherein the apron toe of the apron fence is adapted to be buried in the ground substantially parallel to the fence toe;

3. The silt fence of claim 1 wherein at least one of the configurable barrier sections comprises a rigid support, the rigid support comprising:

a barrier plate, the barrier plate being substantially vertical and having a vertical edge defining the panel edge of the configurable barrier section;
a base plate secured substantially perpendicular to a bottom edge of the barrier plate, the base plate defining the apron edge of the configurable barrier section;
at least one securing prong extending down from the base plate, the securing prong adapted to secure the configurable barrier section to the apron.

4. The silt fence of claim 3 wherein the barrier plate defines a plurality slots proximate the base plate.

5. The silt fence of claim 3 wherein the barrier plate comprises at least one securing hook along the vertical edge of the barrier plate.

6. The silt fence of claim 5 wherein the securing hook is adapted to connect to one of the plurality of posts.

7. The silt fence of claim 6 wherein at least one of the plurality of posts comprises a rigid stake adapted to be mounted in the ground.

8. The silt fence of claim 6 wherein at least one of the plurality of posts comprises:

a stake plate, the stake plate being substantially vertical and having a vertical edge;
a stake base secured substantially perpendicular to a bottom edge of the stake plate, the stake base adapted to rest on the ground;
wherein the vertical edge of the stake plate is adapted to receive the securing hook of the barrier plate.

9. The silt fence of claim 1 at least one of the plurality of posts comprises a rigid stake adapted to be mounted in the ground, the stake comprising at least one fence hook, the fence hook adapted to engage a portion of the fence panel such that the fence panel is maintained in a substantially vertical position.

10. The silt fence of claim 9 wherein the stake defines a tongued slot adapted to receive the portion of the fence panel and wherein the fence hook is disposed on the tongued slot.

11. The silt fence of claim 1 wherein at least one of the configurable barrier sections is comprised of a barrier panel, the barrier panel having an attachment site;

wherein the apron edge of the barrier panel is secured to the apron panel; and
wherein the barrier panel is configured to be movable between a cleaning position and a barrier position;
such that in the cleaning position a portion of the flexible barrier lies flat against the apron panel; and
such that in the barrier position the attachment site is removably secured to one of the plurality of posts.

12. The silt fence of claim 11 wherein the attachment site comprises an eyelet and wherein a tie is used to secure the eyelet to one of the plurality of posts.

13. The silt fence of claim 11 wherein the barrier panel is substantially trapezoidal in shape; and

wherein a first parallel edge of the barrier plate is comprised of the apron edge and the fence edge; and
wherein a second parallel edge of the barrier plate is comprised of the attachment site.

14. The silt fence of claim 11 wherein the attachment site comprises a hem and wherein a tie is used to secure the hem to one of the plurality of posts.

15. The silt fence of claim 14 wherein the hem is formed by creating a fold in the barrier panel parallel to the second parallel edge and securing the second parallel edge to the barrier panel.

16. A barrier section for use with a silt fence comprising a substantially vertical fence panel, the barrier section comprising:

a barrier plate, the barrier plate being substantially vertical and having a vertical edge;
a base plate secured substantially perpendicular to a bottom edge of the barrier plate; and
at least one securing prong extending down from the base plate, the securing prong adapted to secure the configurable barrier section to the ground.

17. The barrier section of claim 16 further comprising at least one connection hook disposed on the vertical edge of the barrier plate, the connection hook adapted to engage the fence panel of the silt fence.

18. The barrier section of claim 16 wherein the barrier plate defines a plurality of slots proximate the base plate, the slots adapted to allow water to flow through the barrier plate while flow of soil past the barrier plate.

19. The barrier section of claim 16 further comprising a barrier post, the barrier post comprising:

a post plate, the post plate being substantially vertical and having a vertical edge;
a post base secured substantially perpendicular to a bottom edge of the post plate, the post base adapted to rest on the ground;
wherein the vertical edge of the stake plate is adapted to engage the vertical edge of the barrier plate.

20. A method for manufacturing a silt fence comprising a fence panel, an apron panel and a plurality of configurable barrier panels, the method comprising:

a) attaching a back edge of the apron panel to the fence panel proximate and parallel to a bottom edge of the fence panel, said attaching step having defined a connection line where the apron panel is attached to the fence panel and a fence toe representing a portion of the fence panel between the connection line and the bottom edge of the fence panel;
b) attaching a first edge of one of the configurable barrier panels to the apron panel and the fence panel perpendicular to the connection line and from a first point proximate a front edge of the apron panel to a second point proximate a top edge of the fence panel; said attaching step having defined an apron toe representing a portion of the apron panel between the first points and the front edge of the apron panel; and
c) repeating step b) for each of the plurality of the configurable barrier panels at a predetermined separation from another one of the plurality of configurable barrier panels.

21. The method of claim 20 further comprising the steps of:

arranging a folded fence system wherein the apron panel would lie flat on the ground, the fence panel would be folded onto the apron panel with a fold line being the connection line and the plurality of barrier panels would be positioned in between the apron panel and the fence panel; and
spooling the folded fence system onto a storage roll.

22. The method of claim 20 wherein the apron panel is attached to the fence panel using a hot glue system.

23. The method of claim 20 wherein the configurable barrier panel is attached to the apron panel and the fence panel by sewing.

Patent History

Publication number: 20090095946
Type: Application
Filed: Oct 10, 2008
Publication Date: Apr 16, 2009
Applicant: The Charles Machine Works, Inc. (Perry, OK)
Inventors: David R. Bazzell (Perry, OK), David A. Rorabaugh (Perry, OK), Edward L. McCombs (Glencoe, OK), Kelvin P. Self (Stillwater, OK)
Application Number: 12/249,760

Classifications

Current U.S. Class: Hinged (256/26); Braced (256/30); Braced (256/31)
International Classification: E04H 17/16 (20060101); E04H 17/22 (20060101);