Abstract:
A post driving device is disclosed. The post driving device slides to a desired position and is essentially locked in place through frictional force. As the post is driven into the ground, the device can be adjusted to a new position along the length of the post.

Description:
CROSS-REFERENCE TO PRIOR APPLICATIONS The present application claims priority to U.S. provisional patent application No. 60/379,255 filed May 10, 2002 and incorporated herein by reference. 
    
    
     
       BACKGROUND  
         [0001]    Posts are used in a variety of applications as structural supports. To provide optimal support, the post must be driven into the ground. This is commonly accomplished by applying a driving force to the top of the post. If the post is tall, an installer may need to stand on the back of a truck bed or balance from a ladder to be above the height of the post. The installer then proceeds to drive the post into the ground with a sledge hammer or similar device. This procedure can be dangerous for the installer and may result in poor or incorrect positioning of the post, including twisting of the post. Further, because the driving force is applied to the top of the post, the post can be easily weakened or otherwise damaged during installation.  
         SUMMARY OF THE PRESENT INVENTION  
         [0002]    The present development is a post driver device that slides over the top of a post before the post is raised to a standing position. The post driver device slides to a desired position and is essentially locked in place through frictional force. As the post is driven into the ground, the device can be adjusted to a new position along the length of the post. Because the post driver device is secured about the body of the post during installation, the post can be held in proper position leading to better alignment of the post. In addition, the driving force is applied through the body of the post rather than strictly at the top so the post is not damaged. 
       
    
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0003]    [0003]FIG. 1 is a perspective view of a post driver device made according to the present invention;  
         [0004]    [0004]FIG. 2 is a side view of the driver of FIG. 1 with the slide driver removed;  
         [0005]    [0005]FIG. 3 is a perspective view of the top of the driver of FIG. 1;  
         [0006]    [0006]FIG. 4 is a top rear perspective view of the driver of FIG. 1 with a T-type post positioned within the driver and with the side plates removed to expose detail of the top locking plate section;  
         [0007]    [0007]FIG. 5 is a top front perspective view of the driver of FIG. 1 with a T-type post positioned within the driver;  
         [0008]    [0008]FIGS. 6A and 6B are side views of the driver of FIG. 1 as it is attached to the T-type post and as is positioned to drive the post into the ground, respectively;  
         [0009]    [0009]FIG. 7 is a perspective side view an alternative embodiment of a post driver device made according to the present invention; and  
         [0010]    [0010]FIG. 8 is front view of the driver of FIG. 7 with a T-type post positioned within the driver. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0011]    The present development is a post driver device. The device is intended to be used with T-type posts such as are commonly used to support fencing materials. When the device is made according to the present invention, it can be used to drive T-type posts into the ground or to extract the posts from the ground. Specific dimensions relevant to the post driver device components are provided herein for the purpose of demonstrating the invention, but these dimensions are not intended to limit the scope of the invention. The dimensions are based on the assumption that the post driver device would be used to install or remove standard commercially available T-posts, but it is anticipated that the device could be used with posts having different dimensions and the device dimensions may be adjusted accordingly.  
         [0012]    FIGS.  1 - 6 B show a first embodiment of a post driver device  10  having a slide guide  14 , a slide driver  16 , a bottom plate  18  and a top locking plate section  20 . The locking plate section  20  includes a slide plate  22 , a post mounting plate  24  and a latching plate  26 . The slide guide  14  has a first end  13  fixedly attached to the bottom plate  18  and a second end  15  fixedly attached to the slide plate  22 . The slide driver  16  forms a moveable sleeve encircling the slide guide  14 .  
         [0013]    The slide guide  14  is a columnar unit positioned between the bottom plate  18  and the slide plate  22 . In the device  10 , the slide guide  14  is illustrated as a hollow column having an essentially square cross-section. The representative embodiment  10  has an external width W 14  of about 2½ inches, an external depth D 14  of about 2½ inches, and an external length L 14  of about 24 inches. The wall thickness may vary but should be adequate to sustain the forces generated when the slide driver  16  is raised and lowered along the slide guide  14 . The slide guide  14  may have alternative cross-sectional shapes, such as circular, oval, rectangular or any shape that can accommodate a moveable sleeve. Optionally, the slide guide  14  may have a solid or filled core or interior and function as intended.  
         [0014]    The slide driver  16  is a tubular unit positioned over the slide guide  14  between the bottom plate  18  and the slide plate  22 . In the device  10 , the slide driver  16  includes a plurality of handles  30  affixed to the driver  16  such that a user could grasp a pair of handles  30  and lower or raise the driver  16  with some measure of force against either the bottom plate  18  or the slide plate  22 . When the driver  16  hits the respective plate  18 ,  22 , the force is transferred to the post thereby driving the post the ground or extracting the post from the ground. A three-handled unit similar to the post driver device  10  allows the user flexibility for positioning the device  10  relative to the post and for operating the slide driver  16 . However, the number and positioning of the handles  30  may vary and the handles  30  are not a required element of the invention, i.e. a no handle device is anticipated within the scope of the present invention.  
         [0015]    Because the user can indirectly affect the force imparted to the post by the speed with which the slide driver  16  hits the bottom plate  18  or the slide plate  22 , it is preferable that the slide driver  16  be designed to move smoothly along the slide guide  14  without excessive wobble or other undesired motion. The driver  16  should also be sized so as to allow the user adequate up-and-down movement along the slide guide  14 . The slide driver  16  of the representative embodiment  10  has an external width W 16  of about 3 inches, an external depth D 16  of about 3 inches, a driver wall thickness T 16  of about ⅜ inches and an external length L 16  of about 12 inches.  
         [0016]    The bottom plate  18  is fixedly attached to the first end  13  of the slide guide  14 . The bottom plate  18  includes a notch  32  on a post face  17  of the plate  18 . The notch  32  is positioned so as to engage a tail  92  of the post  90  when the post  90  is inserted through the post driver device  10  and is preferably about equidistant from the side edges  19 A,  19 B of the plate  18 . The notch  32  functions to maintain the alignment of the post  90  as it is driven into the ground. Optionally, a hook or brad or chain link or similar means  34  to attach a belt or strap or chain or similar collar (not shown) may be attached to one or both sides  19 A,  19 B of the bottom plate  18  to allow the user to reversibly secure the bottom plate  18  to the post  90 .  
         [0017]    The bottom plate  18  must be larger than the external dimensions of the slide driver  16  to ensure that the driver  16  will be held on the slide guide  14 . Further, the plate  18  must be large enough so that when the driver  16  is in contact with the bottom plate  18  the notch  32  is not obstructed by the driver  16 . The bottom plate  18  of the representative embodiment  10  has an external width W 18  of about 4½ inches and an external depth D 18  of about 4½ inches, with the notch  32  having a width W 32  of about ⅜ inches and a depth D 32  of about ¾ inches positioned along the post face about 2{fraction (1/16)} inches from each side  19 A,  19 B.  
         [0018]    Referring to FIGS.  1 - 5 , the top locking plate section  20  includes the slide plate  22 , the post mounting plate  24  and the latching plate  26 . The slide plate  22  is fixedly attached to the second end  15  of the slide guide  14  such that the slide plate  22  lies essentially parallel to the bottom plate  18 . Similar to the bottom plate  18 , the slide plate  22  must be larger than the external dimensions of the slide driver  16  to ensure that the driver  16  will be held on the slide guide  14 . Optionally, the slide plate  22  may have peripheral dimensions similar to the bottom plate  18 . The slide plate  22  of the representative embodiment  10  has an external width W 22  of about 3½ inches and an external depth D 22  of about 4 inches.  
         [0019]    The post mounting plate  24  defines a first edge  36 , a second edge  38 , a pair of sides  40  and an aperture  42 . The mounting plate  24  is secured to the slide plate  22  along the first edge  38  such that the mounting plate  24  is angled away from the slide guide  14  and essentially overhangs the notch  32  of the bottom plate  18 . In the embodiment  10 , the post mounting plate  24  forms an angle θ of approximately 135° relative to the slide plate  22 , but the angle θ may vary as necessary to allow the post mounting plate  24  to properly engage the T-post. The post mounting plate  24  of the representative embodiment  10  has an external width W 24  of about 3½ inches and an external depth D 24  of about 3 inches.  
         [0020]    The aperture  42  abuts the second edge  38  and is contoured to allow the post  90  to be projected through the aperture  42  when the post mounting plate  24  is essentially perpendicular to the post  90 , as shown in FIG. 6A, but further allows the post mounting plate  24  to be tilted to about a 45° angle relative to the post  90 , as shown in FIG. 6B. Referring again to FIG. 4, the aperture  42  is preferably designed and sized to allow the tail  92  to be held securely within the post mounting plate  24  during use. For example, in the embodiment  10 , the aperture  42  has a body void section  44  measuring about 1½ inches by 1½ inches contiguous with the second edge  38  and about 1 inch from either side  40 . The aperture  42  further includes a tail void section  46  measuring about ¾ inch depth by about % inch width.  
         [0021]    The mounting plate  24  is affixed to the latching plate  26  along the second edge  38 . The latching plate  26  projects downward in the direction of the bottom plate  18  and is angled relative to the mounting plate  24  to form an angle φ of about 45°. Along a lower edge  48 , the latching plate  26  includes a notch  28  that is essentially collinear with the tail void section  46 . The notch  28  provides a means for the latching plate  26  to reversibly engage a tooth  94  on the post  90  thereby securing the post driver device  10  to the post  90  during use. The notch  28  further facilitates mounting the driver  10  on the post  90  because when the driver  10  is angled to insert the post  90 , the notch  28  creates a bypass for the teeth  94 .  
         [0022]    Optionally, the top locking plate section  20  may include one or more side braces  50  to further adjoin the slide plate  22  and the post mounting plate  24 , or the slide plate  22 , the post mounting plate  24  and the latching plate  26 . The braces  50  provide added strength to the top locking plate section  20  and, in particular, help to retain the relative angles of the plates.  
         [0023]    To use the post driver device  10 , as shown in FIG. 6A the device  10  is angled to allow the post  90  to slide into the aperture  42 . The post  90  is inserted to the desired height and the slide guide  14  is then tilted downward into a use-position as shown in FIG. 6B until the notch  32  of the bottom plate  18  engages the tail  92  of the post  90 . In the use-position, the latching plate  26  is essentially perpendicular to the body  96  of the post  90  and the notch  28  can be aligned to engage the tooth  94 , as shown in FIG. 5. Further, as shown in FIG. 4, in the use-position, the tail  92  is constrained within the tail void section  46 . The post  90  is then driven into the ground by raising the slide driver  16  along the slide guide  14  and dropping it with some force against the bottom plate  18 . Because the tail  92  is held firm at two points—at the notch  32  and at the tail void section  46 —and because the post  90  is also held along the front edge by the tooth&#39;s interaction with the notch  28 , there is little risk that the post  90  will shift or twist or otherwise become misaligned during installation. Should the user desire to extract the post  90 , the post driver device  10  can be positioned in a manner similar to the positioning for installation but the slide driver  16  is projected with force toward the slide plate  22 .  
         [0024]    An alternative embodiment  110  of the post driver device is shown in FIGS. 7 and 8. Similar to the device  10  of FIGS.  1 - 6 , the device  110  comprises a slide guide  114 , a slide driver  116  with optional handles  130  and a notched bottom plate  118 . The device  110  combines the slide plate  22  and the post mounting plate  24  into a one piece top unit  122  that is fixedly attached to a post slide  126 . Adjustable rods or pins  128  positioned near the top unit  122  reversibly secure the upper portion of the post  90  during installation. A chain or belt or similar strapping can be used to secure a lower portion of the post  90  near the bottom plate  118  during installation. The device  110  does not allow for the post to project through the device  110  but rather the top of the post  90  is contacted by the top unit  122  to drive the post  90  into the ground.  
         [0025]    It is understood that one skilled in the art may make alterations to the embodiments shown and described herein without departing from the scope of the invention. For example, although the embodiments depicted use square/rectangular slide guides, slide drivers and related end plates, it is anticipated that other shapes, such as cylinders, would function as intended. Further, the shapes may be mixed so that a cylindrical slide guide and-slide driver could be used with square/rectangular end plates.