Abstract:
A hold-down nail includes two portions, a stake and a washer, that function in combination to secure a sheet or cover over some type of material, such as an earthen material, and thereby protects the material from the elements and prevents movement of the material due to wind, rain, snow, etc. or foot or other type of traffic over the material.

Description:
PRIORITY CLAIM 
       [0001]    The present application claims the benefit of copending U.S. Provisional Patent Application No. 61/220,805, filed Jun. 26, 2009, which application is incorporated herein by reference in its entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    Embodiments of the present invention relate generally to devices for securing a cover in place over some object to be protected by the cover. 
       BACKGROUND 
       [0003]    Situations arise in a variety of different contexts where some object, such as a pile of dirt or some other material, is located outdoors and is to be protected from the elements, namely wind, rain, snow, etc. Standard hold-down or anchoring systems for the material consist of sandbags lined or connected together in a daisy-chain fashion with rope and placed at 8-10 foot centers across some sort of cover placed over the material to be protected. This sandbagging method requires: i) bags, rope, sand, and labor to fill and tie the bags; ii) labor to transport the heavy bags to the proper location; and iii) labor to tie the bags together to prevent the bags from sliding off the sometimes steep sides of the stockpile of material being protected. When the stockpile of material being protected is ready to be uncovered and used, the sandbags and cover are removed or disposed of due to ultra violet degradation. Typically at this point, however, the sandbags will have holes which make them unusable on another job during their time spent in position on the cover or due to wooden stakes being driven through them to hold them in position. Thus, the sandbags must typically be disposed of after only one use. Accordingly, improved methods and devices are needed to more easily and economically protect stockpiles of material. 
       SUMMARY 
       [0004]    A hold-down nail includes two portions, a stake and a washer, that function in combination to secure a sheet or cover over some type of material, such as an earthen material, and thereby protects the material from the elements and prevents movement of the material due to wind, rain, snow, etc., or foot or other type of traffic over the material. 
         [0005]    According to one embodiment of the present invention, a hold-down nail includes a stake including a shaft having a longitudinal axis extending along a length of the shaft. The shaft also has a head end and a penetrating end and has at least one adjustment tab extending longitudinally along at least a portion of the length of the shaft. A hold-down washer includes an opening having at least one adjustment slot formed at a periphery of the opening. The hold-down washer receives the penetrating end of the shaft through the opening and slides along the longitudinal axis of the shaft towards the head end. Each adjustment slot of the hold-down washer engages or disengages a corresponding adjustment tab at defined points along the shaft and thereby enables the hold-down washer to be locked in multiple longitudinal positions along the shaft. Other embodiments include systems utilizing such nails in combination with a cover and methods of securing such covers to a material to be protected. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIGS. 1A and 1B  are 3-D projections of a moisture barrier hold-down nail according to one embodiment of the present invention. 
           [0007]      FIG. 2  is a cross-sectional diagram illustrating use of a number of the moisture barrier hold-down nails of  FIG. 1  in combination with a protective cover to protect a stockpile of a material from the elements. 
           [0008]      FIG. 3A  is a top view of the washer portion of the moisture barrier hold-down nails of  FIGS. 1 and 2  according to one embodiment of the present invention. 
           [0009]      FIG. 3B  is a cross-sectional view of the stake and washer portions of the moisture barrier hold-down nail in position in the material being protected in the protective system of  FIG. 2  according to one embodiment of the present invention. 
           [0010]      FIG. 3C  is a simplified cross-sectional diagram of the moisture barrier hold-down nail of  FIG. 3B  showing the washer secured in a first position at the second ends of the adjustment tabs and security and a second position at the head portion. 
           [0011]      FIG. 4  is a cross-sectional view of a stake portion of a moisture barrier hold-down nail according to another embodiment of the present invention. 
           [0012]      FIG. 5  is a more detailed cross-sectional view of stake of a moisture barrier hold-down nail according to another embodiment of the present invention. 
           [0013]      FIG. 6  is a 3-D projection of a washer portion of a moisture barrier hold-down nail according to another embodiment of the present invention. 
           [0014]      FIG. 7  is a 3-D projection illustrating several stake portions of moisture barrier hold-down nails according to further embodiments of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]      FIGS. 1A and 1B  are 3-D projections of a moisture barrier hold-down nail  100  according to one embodiment of the present invention. The moisture barrier hold-down nail  100  includes two portions, a stake  102  and a hold-down washer  104 , that function in combination to secure a sheet or cover (not shown) over some type of material to be protected, such as an earthen material.  FIGS. 1A and 1B  show different views of the moisture barrier hold-down nail  100  to better illustrate both the stake  102  and hold-down washer  104 .  FIG. 1A  shows the top side of the washer  104  and also shows that the stake  102  includes a head portion  106  against which the washer  104  presses when the washer is in the position shown in the figures.  FIG. 1B  shows the bottom side of the washer  104  and illustrates adjustment tabs formed on the stake  102  that fit into corresponding adjustment slots on the washer. These adjustment tabs on the stake  102  and adjustment slots on the washer  104  function in combination to allow the washer to be fixed in different positions along the stake to thereby effectively adjust the length of the stake, as will be described in more detail below. 
         [0016]      FIG. 2  is a cross-sectional diagram illustrating a protective system  200  including a number of the moisture barrier hold-down nails  100  of  FIG. 1  in combination with a protective cover  202  to protect a stockpile of material  204  from the elements, which are depicted in  FIG. 2  through the arrow  206 . In operation, a washer  104  is positioned on each stake  102  at the desired position and each stake is thereafter inserted through the cover  202  and into the material  204  being protected, which may be an earthen material such as dirt or sand. The cover  202  may have suitable holes (not shown) formed in the coverthrough which the stake  102  is inserted or may be made from a material, such as plastic, that allows the stakes to be pushed through the cover and into the material  204 . As shown in a cross-sectional diagram of  FIG. 2 , a number of moisture barrier hold-down nails  100  are inserted in this way at various locations on the cover  202  to secure the cover in place over the material  204  and protect the material. The washer  104  of each moisture barrier hold-down nail is secured in place against the cover  202  by the head portion  106  of the stake  102  (when the washer  104  is positioned as shown in  FIGS. 1A and 1B ) and provides a relatively large surface securing the cover in place so that the cover does not easily rip when a force, such as wind, acts on the cover in a direction that would remove the cover from the material if the washer and stake were not in place. 
         [0017]    With the moisture barrier hold-down nail, the only tool required to install the cover  202  is a 2-pound hammer or other suitable tool that can be utilized to pound the stake  102  into the cover  202 . The two-piece design of the moisture barrier hold-down nail  100  allows a large quantity of stakes  102  and washers  104  to be easily transported in a burlap or similar bag. Each moisture barrier hold-down nail  100  is easily installed with a few blows of the hammer. Removal of the moisture barrier hold-down nails  100  is also quick and easy, with the moisture barrier hold-down nails being pulled out and placed into the transport bags for easy transport to the next location or to a storage area for subsequent use. In this way, the moisture barrier hold-down nails  100  may be reused numerous times. 
         [0018]      FIG. 3A  is a top view of the washer  104  of the moisture barrier hold-down nail  100  of  FIG. 1  and is positioned adjacent  FIG. 3B , which is a cross-sectional view of the stake  102  and washer of the moisture barrier hold-down nail of  FIGS. 1 and 2  in position within the material  202  of  FIG. 2  being protected, according to one embodiment of the present invention. In the embodiment of  FIGS. 3A and 3B , the stake  102  includes a shaft having a first diameter D 1  and a longitudinal axis LA extending along a length L of the shaft. The shaft  300  also includes a head end at which a circular head portion  302  having a second diameter D 2  is formed, and a penetrating end  304  opposite the head end. The penetrating end  304  is tapered in the embodiment of  FIG. 3B  so that the stake  102  can be easily inserted into the material  204  being protected. The second diameter D 2  of the head portion  302  is greater than a third diameter D 3  of an opening  305  formed in the center of the washer  104 , as will be discussed in more detail below. 
         [0019]    The stake  102  further includes a number of adjustment tabs  306  formed on a shaft  300  and extending longitudinally along a portion of the length L of the shaft. As seen referring back to  FIGS. 1A and 1B  along with  FIG. 3B , the adjustment tabs  306  are rectangular projections formed on the shaft  300 . In other embodiments the adjustment tabs  306  have different shapes, with any suitable shape being within the scope of embodiments of the present invention. The adjustment tabs  306  are circumferentially spaced on the shaft  300  and have a fourth diameter D 4  relative to the longitudinal axis LA of the shaft  300 . The fourth diameter D 4  of the adjustment tabs  306  is less than the second diameter of the head portion  302  in the embodiment of  FIG. 3B . In this embodiment the adjustment tabs  306  have first ends adjoining the head portion  302  and second ends  308  opposite the first ends, with the second ends  308  being tapered extending towards the penetrating end  304  of the shaft  300 . 
         [0020]    The hold-down washer  104  includes opening  305  and also has at least one adjustment slot  307  formed at the periphery of the opening The adjustments slots  307  are circumferentially spaced around the periphery of the opening  305  such that each of the adjustment slots  307  can be aligned with a corresponding adjustment tab  306  on the shaft  300 . The hold-down washer  104  receives the penetrating end  304  of the shaft  300  through the opening  305  and slides along the longitudinal axis LA of the shaft towards the head portion  302  of the shaft. In the embodiment of  FIG. 3B , prior to the washer  104  reaching the adjustment tabs  306  the washer may be rotated freely about the shaft  300 . The adjustment slots  307  of the hold-down washer  104  are said to engage the adjustment tabs  306  on the shaft when not aligned with the adjustment slots such that the washer no longer longitudinally slides towards the head portion  302 . Instead in this situation the washer  104  “engages” the tapered second ends  308  of the adjustment tabs  306 . The diameter D 3  of the opening  305  is less than the diameter D 4  of the tabs  306  and thus the tabs engage or stop the washer  104  at this position. 
         [0021]    Conversely, the adjustment slots  307  of the hold-down washer  104  are said to “disengage” the adjustment tabs  306  on the shaft when aligned with the adjustment slots such that the washer, even upon reaching the second ends  308  of the adjustment tabs, continues sliding longitudinally towards the head portion  302  and finally stops upon reaching the head portion  302 . In this way the adjustment tabs  306  and adjustment slots  307  operate in combination to enable the hold-down washer  104  to be locked in multiple longitudinal positions along the shaft  300 . Note that in the embodiment of  FIG. 3B  the stake  102  further includes tapered retaining projections  310   a  and  310   b  formed at different longitudinal positions along the shaft and function to resist removal of the stake from the material  204  being protected. Different numbers and shapes can be utilized for such retaining projections  310 , and such projections are also omitted in other. 
         [0022]      FIG. 3C  is a simplified cross-sectional diagram of the moisture barrier hold-down nail  100  of  FIG. 3B  showing the washer  104  secured in a first position at the second ends of the adjustment tabs  306  and secured in a second position at the head portion  302 . In the first position, the washer  104  is oriented such that the adjustment slots  307  (not shown in  FIG. 3C ) engage the adjustment tabs  306 , meaning that the adjustment slots are not aligned with the adjustment tabs. As a result, the opening  305  and the washer  104  presses against the tapered second ends  308  of the adjustment tabs  306  as the washer is moved longitudinally upward toward the head portion  302  and in this way is secured in the first position. Conversely, when the adjustment slots  307  in the washer  104  are aligned with the adjustment tabs  306  the washer  104  is moved all the way up the shaft  300  until the washer presses against the head portion  302  and is thereby secured in the second position. 
         [0023]    The adjustment tabs  306  and adjustment slots  307  in the washer  104  ( FIG. 3A ) may be different in number and shape in other embodiments of the present invention. For example, in another embodiment the first ends of the adjustment tabs  306  do not extend all the way up to the head portion  302 . Instead, each adjustment tab  306  includes a slot  312  having a thickness T as shown through the dotted lines for the adjustment tab on the left in  FIG. 3C . With this embodiment once the washer  104  is pressed against the head portion  302  the washer can be rotated so that the adjustment slots  307  are no longer aligned with the adjustment tabs  306  and in this way the washer is secured in the second position pressing against the head portion. 
         [0024]    In another embodiment the adjustment tabs  306  extend farther down the shaft  300  and include locking slots  314  formed in selected longitudinal locations along the shaft. Once again, this is illustrated in  FIG. 3C  for only one of the adjustment tabs on the left side of the moisture barrier hold-down nail  100  merely to simplify the figure, with these expanded portions of the adjustment tabs being designated as  306  in the figure. The washer  104  may then be secured in position at any of the locations of the locking slots  314  to thereby provide a number of effective lengths for the stake  102 . The ability to secure the washer  104  in different longitudinal positions along the stake  102  enables the effective length of the stake to vary the penetration into the material  204  being protected, which eliminates the need to have different lengths of stakes at the job site for different types of materials. 
         [0025]      FIG. 4  is a cross-sectional view of a stake  400  of a hold-down nail according to another embodiment of the present invention. In this embodiment, the stake  400  has an overall length L formed by three segments L 1 , L 2 , and L 3  as shown. The first segment L 1  includes adjustment tabs  402  extending from a head portion  404  and having tapered ends towards the tip end of these adjustment tabs. A first locking slot S 1  is formed at the end of these adjustment tabs  402  and adjustment tabs  402  extend on the second segment L 2  of the stake  400 , and once again have tapered ends towards the tip end of these adjustment tabs. The tip end of the third segment L 3  is also tapered, with the taper associated with each of the segments L 1 , L 2 , and L 3  being designated through an angle θ. In the depicted example embodiment the taper angle θ is 10 degrees. 
         [0026]      FIG. 5  is a more detailed cross-sectional view of stake  500  of a moisture barrier hold-down nail according to another embodiment of the present invention. The stake  500  has an overall length L formed by two segments L 1  and L 2  as shown. The first segment L 1  includes adjustment tabs  502  extending from a head portion  504  and having tapered ends towards the tip end of these adjustment tabs. In this embodiment the head portion  504  includes a plurality of holes  506  extending through the head portion  504 . Lines or rope can be threaded through such holes  506  to help the stake  500  secure a cover (not shown in  FIG. 5 ) in place. The second segment L 2  of the stake  500  is tapered towards the tip end of the stake. The taper associated with each of the segments L 1  and L 2  is again designated through an angle θ, which in the depicted example is 15 degrees. 
         [0027]      FIG. 6  is a 3-D projection of a washer  600  of a moisture barrier hold-down nail according to another embodiment of the present invention. The washer  600  includes an outer circumferential ring  602  at a first radial distance from center C of the moisture barrier hold-down washer and having an outer radial edge  604  defining a diameter of the hold-down washer. The outer circumferential ring  602  also includes an inner radial edge  606 . The washer  600  further includes an inner circumferential ring  608  at a second radial distance that is less than the first radial distance. A plurality of radial projections  610  are equally circumferentially spaced, with each radial projection extending between the opening in the center C of the circular-shaped washer  600  and the inner radial edge  606  of the outer circumferential ring  602 . This embodiment saves material required to form the washer  600 . The radial projections  610  are not equally circumferentially spaced in other embodiments of the present invention, and may also have profiles that vary in the radial direction. 
         [0028]      FIG. 7  is a 3-D projection illustrating several stakes  700   a,    700   b,  and  700   c  for moisture barrier hold-down nails according to further embodiments of the present invention. As seen in these embodiments the number, length, and specific structure of the adjustment tabs and diameters of the various segments of the stakes vary in different embodiments of the present invention. 
         [0029]    The stakes and washers of the moisture barrier hold-down nail in embodiments of the present invention may be formed from a variety of different materials, such as steel, aluminum, or impact resistant plastic or any other suitable material. Impact resistant plastic would in many situations be advantageous due to its lighter weight and lower cost, particularly relative to sandbags. Furthermore, when the moisture barrier hold-down nails are formed from impact resistant plastic they can be stored in wet locations indefinitely without significant damage to the moisture barrier hold-down nail  100 . The labor savings for installation and removal are substantial compared to the sandbag method and the moisture barrier hold-down nails are reusable. 
         [0030]    The washer  104  may be manufactured in various sizes depending on the thickness and durability of the cover  202  ( FIG. 2 ) and the degree of wind exposure or other forces. The outside edges of the washer  104  that may come in contact with the cover have a suitable profile, such as a radiused edge profile, to reduce the likelihood of the washer tearing the cover. 
         [0031]    Various sizes of the moisture barrier hold-down nail  100  can be formed for different applications. In one embodiment, a smaller version of the moisture barrier hold-down nail  100  is used for securing sheets of plastic of other covers in crawl spaces of homes and for “underslab” vapor barriers prior to placing rebar, insulation and concrete. The moisture barrier hold-down nail  100  in another application is used by landscapers to secure weed block fabrics or filter fabrics prior to installing topsoil or mulch. Note that the stake  102  and washer  104  may physically be two separate components as illustrated in the embodiment of  FIG. 1  or alternatively the washer and stake may be integrated to form a unitary embodiment of the moisture barrier hold-down nail  100 . 
         [0032]    In the present description, certain details are set forth in conjunction with the described embodiments of the present invention to provide a sufficient understanding of the invention. One skilled in the art will appreciate, however, that the invention may be practiced without these particular details. Furthermore, one skilled in the art will appreciate that the example embodiments described herein do not limit the scope of the present invention, and will also understand that various modifications, equivalents, and combinations of the disclosed embodiments and components of such embodiments are within the scope of the present invention. Embodiments including fewer than all the components of any of the respective described embodiments may also be within the scope of the present invention although not expressly described in detail herein. Finally, the operation of well-known components and/or processes has not been shown or described in detail to avoid unnecessarily obscuring the present invention.