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FIELD OF THE INVENTION  
       [0001]     The present invention is in the field of stakes used to support concrete forms or barriers that are used along the outside of an area in which concrete is to be poured, so as to contain the poured concrete in that area.  
       BACKGROUND AND DESCRIPTION OF RELATED ART  
       [0002]     Concrete form stakes are typically used to secure wooden boards or “forms” around the perimeter of a concrete pouring area, the stakes driven partway into the ground along the outside face of a form to hold it securely in place before, during, and after the pouring operation. Known stakes come in many shapes and sizes, for example homemade stakes made from scrap wood at the construction site as well as different types of commercial stake made from wood, plastic, and metal.  
         [0003]     Another type of stake used in concrete pouring operations is known as a screed stake, used in spaced pairs to hold screed rods or bars in an even plane across the area to be poured to ensure that the concrete is level and smooth.  
         [0004]     My earlier U.S. Pat. No. 6,588,164, issued Jul. 8, 2003, discloses a stake especially adapted for use as a screed stake, but which can also be used as a form stake. This screed/form stake has a flat rear face and a U-shaped upper cradle portion extending from the front face of the stake, the cradle designed to mate with a separate driver. The driver also has a flat rear face, and a screed-rod-shaped portion that extends from the front face of the driver to mate with a screed rod groove in the cradle portion of the stake. When the lower end of the driver is mated with the stake&#39;s upper cradle, the upper end of the driver serves as a pounding surface to drive the stake into the ground. The upper surface of the screed-rod-shaped portion of the driver can be used as a screed rod elevation-measuring surface when seated in the cradle, providing a platform for a transit to measure whether the stake has been pounded in far enough to support a screed rod at the proper height. The screed/form stake has holes formed along its face for securing it to a concrete form with screws or nails. When used as a form stake, the stake is driven home with the same driver used for screeding operations, with the flat back of the driver allowing it to be used against the face of the form without interference. As shown in the patent, the stake can be driven to a point where its cradle is below the upper surface of the form. The stake is typically removed from the exterior face of the form after the concrete has been poured and has set.  
         [0005]     I have a co-pending U.S. patent application Ser. No. 10/957,348 filed Oct. 2, 2004 for a stake designed specifically for use as a form stake. The stake can be pounded or driven into the ground with any non-specialized driving tool, such as a hammer or mallet or even a boot, and naturally levels itself at the top of the concrete form when pounded with such a tool. When the form is no longer needed, the stake can be easily pulled out of the ground with fingers or the claw of a hammer or tool. The form stake has a relatively wide, flat body with a flat rear face, and a forward-facing T-shaped flange structure extending from the front face of the stake. The T-shaped flange structure has a horizontal driving shelf with a uniform, level impact surface at the top of the stake, and a central vertical rib section extending downwardly from the driving shelf with a depth equal to the depth of the shelf protruding beyond the face of the stake. The driving shelf forms the top surface of the stake. The vertical rib bisects the stake. In a preferred form, the underside of the driving shelf has a predominantly perpendicular or acutely-angled surface on both sides of the central rib for grasping with the fingertips or hooking with a tool to pull the stake out of the ground. Although the form stake is lighter and less expensive to manufacture than my previous screed/form stake, it is easier and faster and stronger to use as a form stake.  
         [0006]     Perhaps the most common type of concrete form stake is a simple nail stake, which looks and functions like a giant nail, except that it typically has a number of holes formed along the shank of the nail for securing it to a wooden form board.  
         [0007]     Nail type stakes are often used for other purposes, most notably as tent stakes, since they easily penetrate even the hardest ground. When used as tent stakes, nail stakes are sometimes provided with a cross-piece frictionally held in place on the upper end of the shank below the nail-head to provide a pull handle and a place to tie guy-lines from the tent.  
       BRIEF SUMMARY OF THE INVENTION  
       [0008]     The present invention is a form stake with a narrow ground-penetrating shank terminating at its upper end in a wider, horizontal, integral driving shelf that allows the stake to be pounded or driven into the ground with any non-specialized driving tool, such as a hammer or mallet or even a boot, and naturally levels itself at the top of the concrete form when pounded with such a tool. When the form is no longer needed, the stake can be easily pulled out of the ground with fingers or the claw of a hammer or tool. The driving shelf has a wide, uniform, level impact surface at the top of the stake, the preferably cylindrical ground-penetrating shank extending downwardly from the center of the driving shelf and tangentially aligned with a flat, rear, form-abutting edge of the driving shelf. In a preferred form, the shank has a diameter or width equal to the front-to-back depth of the driving shelf. The outer ends of the driving shelf extend freely beyond and above the shank body.  
         [0009]     In a further form of the invention, the underside of the driving shelf has a pair of opposing force-transferring flanges extending downwardly and inwardly at an acute angle to an upper end of the shank. The flanges are thin-walled and centered on the underside of the driving shelf. In a preferred form, the flanges extend from an intermediate portion of the underside of the driving shelf, such that the outer ends of the shelf extend beyond the uppermost portions of the flanges.  
         [0010]     In a further form of the invention, the shank portion of the stake is cruciform in section, with the force-transferring flanges merging into two side ribs of the cruciform shank.  
         [0011]     The present form stake is lighter and less expensive to manufacture than my previous form stake, is easier and faster to use as a form stake, and is less likely to wander or cant when driven into hard ground. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]      FIG. 1  is a perspective view of two form stakes according to the invention, one prior to being driven into the ground against a wooden form, and the other driven in level with the top of the form.  
         [0013]      FIG. 2  is a front elevation view of a stake as shown in  FIG. 1 .  
         [0014]      FIG. 3  is a side elevation view of the stake of  FIG. 1 , partially driven into the ground against the outside face of a concrete form.  
         [0015]      FIG. 4  is a side elevation view similar to  FIG. 3 , but with the stake fully driven into position adjacent the concrete form.  
         [0016]      FIG. 5  is a top plan view of the stake of  FIG. 4  driven into the ground against the face of the form, with the shank portion of the stake shown in hidden lines.  
         [0017]      FIG. 6  is a side elevation view similar to  FIG. 3 , but shows the stake being pulled from its fully driven position by hand.  
         [0018]      FIG. 7  is a perspective view of a stake similar to the stake in  FIGS. 1-6 , but with a cruciform shank.  
         [0019]      FIG. 7A  is top plan view of the stake of  FIG. 7 , with the cruciform shank section shown in hidden lines. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0020]     Referring first to  FIGS. 1 and 2 , the invention is illustrated in a first illustrative example as form stake  10 . Stake  10  is preferably molded as one piece from a suitably strong plastic material, for example a nylon or ABS plastic, although other plastics and materials such as wood or metal can be used, and although the stake is not limited to one-piece construction. Stake  10  is used to laterally secure a wooden form  12  in place around an area in which concrete  13  is to be poured. As shown in the Figures, stake  10  is driven into the ground with its rear surface against the outer face of form  12  to prevent the form from shifting during pouring or curing of the concrete against the opposite inner face of form  12 . The length of stake  10  can vary from under a foot to several feet in length, but in the illustrated embodiment is on the order of twelve to fourteen inches in length.  
         [0021]     Stake  10  has a cylindrical ground-penetrating shank  16  terminating at its upper end in a flat, horizontal driving shelf  18  formed as an integral part of the stake, whether by molding, welding, mechanical attachment, or some other method for giving the driving shelf  18  a permanent, non-rotating, fixed driving connection to shank  16 . The lower end of shank  16  preferably terminates in a point  16   a  that helps the shank penetrate hard ground.  
         [0022]     As best seen in  FIGS. 2 through 4 , driving shelf  18  has a flat top surface  18   a , a flat bottom surface  18   b , a rear edge  18   c  flush at  17  with the tangentially rear-most portion  16   b  of shank  16 , and a front edge  18   d  flush at  17  with the tangentially front-most portion  16   c  of shank  16 . Driving shelf  18  extends beyond both sides of shank  16 , in the illustrated embodiment having a width (for example, 2.875 inches) at least three times the diameter (for example, 0.875 inches) of shank  16 . The flat top surface  18   a  of driving shelf  18  forms the upper end of the stake, with a surface area greater than the cross-sectional area of shank  16 . As best shown in  FIG. 5 , when stake  10  is viewed from above, the relatively wide, flat, upper face  18   a  of driving shelf  18  is the only visible surface, overlying the circumference of shank  16 , and therefore presenting a significantly greater driving face.  FIG. 5  shows the tangential or flush alignment of the rear-most and front-most vertical edges or surfaces  16   b ,  16   c  of shank  16  with the rear and front edges  18   c  and  18   d  of the driving shelf, allowing the form-facing side of stake  10  to present a smooth, unbroken sliding face to form  12  as stake  10  is driven into the ground against the form until the rear edge  18   c  of the driving shelf is against the form. While a perfectly smooth, flat, uniform upper surface  18   a  is preferred, it will be understood that minor variations such as different textures or surface finishes or patterns that leave the upper surface generally flat relative to the driving force and the top of the concrete form are acceptable. It will be understood that if both the rear and front edges  16   b  and  16   c  of the shank are flush with the rear and front driving shelf edges  18   c  and  18   d  as shown in  FIG. 5 , stake  10  can be used reversibly against form  12 .  
         [0023]     The junction of the upper end of shank  16  and the lower surface of driving shelf  18  is reinforced with angled fillets or flanges  20  extending from intermediate portions of the underside of the driving shelf to the sides of the upper end of shank  16 , centered on the underside of the driving shelf  18  in alignment with the long axis of the shelf. Flanges  20  are preferably molded in one piece with the rest of stake  10 . Flanges  20  are also preferably thin-walled, as illustrated, allowing an essentially tangential connection to the sides of shank  16 , and providing room for fingers or a tool to grasp the underside of shelf  18  in the vicinity of the flanges. Flanges  20  efficiently transfer driving force from regions of the driving shelf  18  on either side of shank  16  into the shank, reducing stress at the junction of shelf and shank, and helping to keep the shank driven straight down even when the driving force is off-center.  
         [0024]     Referring to  FIGS. 3 and 4 , stake  10  can be pounded into the ground with any non-specialized tool, for example the illustrated mallet  30 , since the upper driving surface  18   a  of the stake is a flat, wide, uniform force-distributing surface. No specialized driving tool is necessary, and, in soft soil, foot and even hand pressure (with body weight behind it) may be used to push against the relatively wide, even surface of the driving shelf. Driving the stake with non-specialized tools is accordingly both effective and comfortable, whether using a hammer, a mallet, a rock, a board, a boot, a hand, or any other convenient implement.  
         [0025]     As best shown in  FIGS. 1 and 4 , stake  10  tends to automatically level itself both vertically and side-to-side at the upper surface  12   a  of form  12 , since a non-specialized driver (especially a driver with a driving or impact face wider than the depth of shelf  18 ) will tend to hit the upper surface  12   a  of the form when the flat upper surface  18   a  of driving shelf  18  is even with the upper surface of the form. Assuming that the overall length of stake  10  allows a sufficient portion of the stake to be driven into the ground for good holding power relative to the ground, leaving the stake&#39;s upper end  18  approximately even with the upper edge of form  12  provides the strongest possible support for the form. Leaving the upper surface of the stake  10  even with the top of form  12  also ensures that concrete smoothing tools can be run across the top of the form without interference. The overall jobsite is also given a neater, more professional appearance with all form stakes driven in evenly against the forms. And the risk of overdriving the form stake to a point where it becomes difficult to remove from the ground is reduced or eliminated.  
         [0026]     Referring next to  FIG. 6 , stake  10  is also easily pulled out of the ground when the concrete forming operation is done. The lower surface or underside  18   b  of driving shelf  18  is preferably perpendicular to the shank  16  of stake  10  so that maximum pulling force can be exerted on the stake through the shelf with the fingers or a tool hook or claw, as shown. The lower surface  18   b  can also be angled inwardly at an acute angle to the front face of stake  10  (not shown), for an even better hooking action on the shelf when the stake is being pulled from the ground. While the lower surface  18   b  is preferably flat and uniform as shown, it is possible to vary the contour so long as significant gripping or hooking portions are perpendicular or acute.  
         [0027]     Holes  22  through shank  16  allow the stake to be secured to the face of form  12  in known manner, for example with nails or screws driven through holes  22  into the face of the form. Holes  22  preferably pass through shank  16  perpendicular to rear and front edges  18   c  and  18   d  of shelf  18 , and therefore perpendicular to a form  12  being supported by a driven stake  10 . Holes  22  could also be acutely angled, but angles greater than 45° tend to put nails or screws inserted through the holes at an ineffective angle relative to the face of form  12 .  
         [0028]     Referring to  FIG. 6 , although the thin walls of flanges  20  leave room for fingertips to hook the underside  18   b  of shelf  18  on either side of the upper end of shank  16 , upper portions of flanges  20  extend only partway toward outer ends  18   e  of the shelf, allowing fingers or a hooking tool to wrap fully under (and even around the outer ends of the shelf  18  when the shelf reaches a point higher than form  12 ) for a better grip, as shown in phantom. This gives the person removing stake  10  the ability to exert both a very strong vertical pulling force, but also creates a moment arm relative to the shank body to provide side-to-side leverage to rock or loosen the shank to help free the stake from difficult ground. This is useful where the stake becomes firmly lodged in the ground, for example if a rough shank surface finish or holes  22  attract concrete dust or moist or compacted dirt or snow that can cement or freeze the stake into the ground.  
         [0029]     Referring next to  FIGS. 7 and 7 A, a modified version of stake  10  is illustrated at  100 , having a cruciform-section shank  116 , a driving shelf  118  essentially the same as shelf  18  in  FIGS. 1-6 , and force-transferring flanges  120  similar to previously-described flanges  20 . The cruciform shank  116 , centered under driving shelf  118  and having a narrow, ground-penetrating body, will generally be lighter than cylindrical shank  16  if made from the same material, and may have some advantage in penetrating and holding in certain types of soil. The diameter of shank  116  and its relationship to driving shelf  118  is preferably similar to that of shank  16  and shelf  18 , with the same tangential alignment of the rear and front ribs  116   c  and  116   d  with the rear and front edges  118   c  and  118   d  of driving shelf  118 , and the same proportion of shelf width to shank diameter. The side ribs  116   e  of shank  116  lend themselves to being extended to form (or to merge with) flanges  120  at the upper end of the shank.  
         [0030]     It will be understood that while the circular and cruciform shanks  16  and  116  illustrated above are currently preferred, other cross-sectional shapes are possible, provided that at least the central rear edge or tangent of the shank body centered relative to drive shelf  18  is flush or tangential with the center of the rear form-facing edge  18   c  of shelf  18 . It will also be understood that while a rectangular shelf  18  is preferred, other symmetrical shapes with a flat rear form-facing edge are possible. And while the illustrated embodiments show single front and rear vertical edges or surfaces of the shank body aligned with the front and rear edges of the driving shelf  18 , it is possible to align multiple front and rear edges of surfaces of a shank body with central portions of the front and rear edges of driving shelf  18 , for example by rotating the cruciform shank body  116  of  FIGS. 7 and 7 A approximately 45°.  
         [0031]     It will be understood that the length and width and relative dimensions of shank  16  and driving shelf  18  can vary according to the anticipated height of the forms with which it will be used, the nature of the ground into which stake  10  will be driven, and the weight or force of concrete that is anticipated against the form.  
         [0032]     While stake  10  is especially designed for use as a form stake, it may find use in other applications for providing good holding power against significant forces in loose soil or sand or even snow.  
         [0033]     It will be understood that the disclosed embodiment is representative of a presently preferred form of the invention, but is intended to be illustrative rather than definitive of the invention. The scope of the invention is defined by the following claims. I accordingly claim:

Summary:
A form stake having a narrow vertical shank body terminating at its upper end in a wider, flat driving shelf whose outer ends extend far enough from the shank body to provide grasping or hooking surfaces on the underside of the driving shelf spaced from the shank. At least a rearmost edge or surface of the shank is aligned flush with the rearmost edge of the driving shelf, allowing the entirety of the stake to be driven smoothly down into the ground adjacent the face of a form board. In a preferred form the stake includes reinforcing flanges extending from the underside of the driving shelf to an upper end of the shank, the flanges terminating short of the outer ends of the driving shelf.