Abstract:
An impact tool for use in removing a non-threaded fastener from a first substrate anchored to a second substrate by the fastener. The tool includes a shank having a longitudinal axis, first and second ends, and an exterior surface. A driving head is located on one end of the shank and a fastener exposure/dimpling head located on the other end. The fastener exposure/dimpling head includes a fastener receiving cavity, a cutting lip extending outwardly from said fastener receiving cavity, and a dimpling section located between the cutting lip and the outer surface of the shank. The cutting lip is placed around the nailhead and the driving head tapped to expose the nailhead. The dimpling section creates a cavity in the surface of the first substrate which can subsequently be filled.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to a tool which exposes the head of a non-threaded fastener for easy removal from an object anchored to a wood substrate by the fastener, and prepares the surface of the anchored object adjacent the fastener for easy repair after removal of the fastener.  
           [0002]    Non-threaded fasteners, such as nails and staples, are used to anchor many things to a wood substrate. A typical example is the use of nails to attach sheet rock to wooden studs. Nails are used to attach wood to wood, such as attachment of wooden cabinets to wooden studs.  
           [0003]    If it is required to remove the nail from the anchored material, claw hammers or special tools having a claw are typically used with the claw being wedged under the nailhead and mechanical extraction leverage applied to the embedded nail shank through the handle of the claw tool. Use of a claw device usually causes considerable surface damage to, or total destruction of, the anchored object during extraction of the nail.  
           [0004]    A number of tools have been suggested to alleviate this problem, such as the nail puller tools described in U.S. Pat. Nos. 4,658,457 and 4,776,568. However, these tools do not provide the leverage required to quickly remove the shank of a nail tightly imbedded in the wood substrate.  
         SUMMARY OF THE PRESENT INVENTION  
         [0005]    The present invention provides an impact tool which exposes a fastener head embedded in a substrate for easy engagement by a conventional claw device while saving the visual and physical integrity of the adjoining substrate area, and at the same time creates a dimpled depression thereabout which, after extraction of the fastener, can be easily filled.  
           [0006]    The tool includes a cylindrical body portion (shank) one end of which constitutes a driving head and the other end of which constitutes a fastener exposure/dimpling head.  
           [0007]    The fastener exposure/dimpling head includes a fastener receiving cavity, a cutting lip extending outwardly from the fastener receiving cavity, and a rounded dimpling section located between the cutting lip and the outer surface of the shank. Preferably, a transition section is located between the cutting lip and the dimpling section. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    [0008]FIG. 1 is a perspective view of the tool of the present invention;  
         [0009]    [0009]FIG. 2 is an elevation view of the tool of the present invention;  
         [0010]    [0010]FIG. 3 is an enlarged elevation view of the fastener exposure/dimpling head of the tool of the present invention;  
         [0011]    [0011]FIG. 4 is an enlarged bottom plan view of the tool of the present invention;  
         [0012]    [0012]FIG. 5 is an elevation view of the tool of the present invention being tapped into place with a hammer;  
         [0013]    [0013]FIG. 6 is an enlarged view of a nailhead and adjacent area of the anchored object after having been subjected to the tool of the present invention; and  
         [0014]    [0014]FIG. 7 is an elevation view showing the removal of a nailhead that has been exposed by the tool of the present invention with a conventional claw device. 
     
    
     DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0015]    The non-threaded fastener removal tool  10  of the present invention includes a cylindrical body (shank)  12 . At one end (the outer end) of shank  12  is a rounded (convex) driving head  14 . At the other end (the inner end) of shank  12  is a nailhead exposure/dimpling head  20  (FIG. 4).  
         [0016]    Although shank  12  is preferably cylindrical in shape, other shapes may be used.  
         [0017]    The length of shank  12  is such as to provide sufficient space for a user to easily grip it with his fingers. A length of about 3 inches to about 4 inches has been found to be satisfactory.  
         [0018]    The diameter of shank  12  is such as to provide sufficient space for the proper functioning of the nailhead exposure/dimpling head  20  described below. A diameter of about 1.0 inch or less has been found to be satisfactory.  
         [0019]    Head  20  has an interior portion including a cylindrical nailhead receiving cavity  22 , a conical end cavity  24  which communicates with nailhead receiving cavity  22 , and a cylindrical cleanout channel  26  that communicates nailhead receiving cavity  22  and conical end cavity  24  with the exterior surface of shank  12 . Conical end cavity  24  provides easier removal of accumulated debris.  
         [0020]    The longitudinal axis of cylindrical nailhead receiving cavity  22  is coaxial with the longitudinal axis of shank  12  of tool  10 .  
         [0021]    In a preferred embodiment, cylindrical cleanout channel  26  extends upwardly at an angle of about 30 degrees to the longitudinal axis of shank  12  of tool  10 .  
         [0022]    Nailhead receiving cavity  22  has a diameter slightly larger than the diameter of the nailhead of the nail to be removed. The diameter of nailhead receiving cavity  22  should be close to the diameter of the nailhead, but not so close as to cause the nailhead to be driven into the anchored object and substrate during use of the tool  10 . A clearance of about {fraction (1/64)}th of an inch between the periphery of the nailhead and the wall of cavity  22 , i.e., an overall diameter of about {fraction (1/32)} inch greater than the diameter of the nailhead, has been found to be satisfactory for many nail sizes.  
         [0023]    For nails having a size of between about 10D and about 20D, a diameter of about {fraction (7/16)} inch for nailhead receiving cavity  22  has been found to be satisfactory. For nails having a size of between about 3D and about 8D, a diameter of about {fraction (3/8 )}inch for nailhead receiving cavity  22  has been found to be satisfactory. For nails having a size of 2D, a diameter of about ¼ inch for nailhead receiving cavity  22  has been found to be satisfactory.  
         [0024]    The exterior of head  20  includes a cylindrical cutting lip  30 , an angled transition section  32  and a rounded dimpling section  34 .  
         [0025]    Cylindrical cutting lip  30  extends outwardly from nailhead receiving cavity  22  and has an inside diameter that is the same as the diameter of nailhead receiving cavity  22 , the longitudinal axis of cutting lip  30  being an extension of the longitudinal axis of nailhead receiving cavity  22 . The outer edge of cutting lip  30  is relatively sharp and has a high angle of attack to the surface plane of the anchored substrate (i.e., about 90 degrees) during use, thereby providing quick initial entry of the nailhead exposure/dimpling head  20  into the area of the anchored object adjacent the fastener to be removed.  
         [0026]    Although the invention is not limited to any particular wall thickness or depth for cutting lip  30 , a wall thickness of about 0.9 mm (0.033 inch) and a depth of about 0.794 mm (0.031 inch) has been found to be satisfactory for many nail sizes.  
         [0027]    Angled transition section  32  provides an angle of attack intermediate the substantially perpendicular attack angle of cutting lip  30  and the relatively flat attack angle of rounded dimpling section  34 . A transition section  32  having an angle of about 30 degrees to the longitudinal axis of shank  12  of tool  10  has been found to be satisfactory for many nail sizes.  
         [0028]    Rounded dimpling section  34  has the lowest angle of attack to the surface of the anchored substrate from which the fastener is being removed. The purpose of rounded dimpling section  34  is to provide sufficient space around the fastener being removed to allow access thereto by a claw removal device. In addition, dimpling section  34  leaves a smooth, dimpled depression around the fastener hole to allow easy filling with patching material after removal of the fastener.  
         [0029]    In a preferred embodiment, rounded dimpling section  34  is substantially a one-quarter arc of a circle, preferably having a radius of about 6.35 mm (0.250 inch).  
         [0030]    In a preferred embodiment, the distance between the outer edge of cutting lip  30  and the apex of conical end cavity  24  is about 15.875 mm (0.625 inch).  
         [0031]    FIGS.  5 - 7  illustrate use of tool  10  to remove a nail  40  having a nailhead  42  and a shank  44  from a substrate  46  anchored to wood member  48  by nail  40 .  
         [0032]    Tool  10  is positioned with the longitudinal axis of shank  12  substantially perpendicular to the surface plane of anchored substrate  46  and with the cutting edge of cylindrical cutting lip  30  surrounding the nailhead  42  of the nail  40  to be removed from the anchored substrate  46  and wood member  48 . A hammer  50  is used to drive nailhead exposure/dimpling head  20  into that portion of anchored substrate  46  surrounding nail  40 . The hammer  50  is used to strike rounded driving head  14  of tool  10  several times to ensure that the depth of cutting lip  30 , transition section  32  and dimpling section  34  is sufficient to expose nailhead  42 , and to expose a portion of adjacent shank  44  sufficient to allow a claw to removingly engage nailhead  42 .  
         [0033]    Upon cutting lip  30  entering the area of the anchored substrate  46  surrounding nailhead  42  and its associated shank  44 , any existing mechanical bond or glue bond between the nailhead and the anchored member is broken. As cutting lip  30  is driven downwardly it tends to cause the nailhead  42  to be pushed slightly above the adjacent upper planar surface of the anchored substrate  46 , thereby creating additional space for insertion of a claw removal device thereunder.  
         [0034]    Tool  10  is then removed, leaving nailhead  42  and a small upper portion of shank  44  exposed, as shown in FIG. 6. A dimpled depression  47  surrounds nailhead  42 .  
         [0035]    A clawed nail removal device, such as cat&#39;s paw  60 , is then used to remove nail  40 , as seen in FIG. 7. Tool  10  or a piece of wood or other material (not shown) is placed against the surface of anchored substrate  46  in the area where the head of cat&#39;s paw  60  will come into contact in order to prevent damage to the surface of anchored substrate  46  in that area during nail removal.  
         [0036]    After removal of nail  40 , suitable filler material can be placed into dimpled depression  47  and smoothed out.  
         [0037]    If debris from anchored substrate  46  enters nailhead receiving cavity  22 , it is normally continuously pushed up to the top of conical end cavity  24  and out through cleanout channel  26 . If for some reason the debris becomes embedded, a nail or piece of wire can be inserted into cylindrical cleanout channel  26  to force the embedded material out of nailhead receiving cavity  22 .  
         [0038]    It is envisioned that tool  10  would be marketed in sets containing two or more tools  10  having nail receiving cavities  22  of different diameters for use with nails of various sizes. For example, a set of three tools  10  having the nail receiving cavity  22  diameters described above relative to 2D, 3D-8D and 10D-20D nail size ranges would be a convenient set to have available for use.  
         [0039]    Tool  10  has been described in the preferred embodiments above as being a free standing tool. However, tool  10  can be removably or permanently attached to a cat&#39;s paw  60  in the area  62  delineated by the dotted line in FIG. 7, or to other nail removal claw devices. In such alternative embodiments the length of tool  10  can be shortened and the top  14  would be flattened to allow attachment to a nail removal claw device.  
         [0040]    Although the illustration of the nail  40  in the drawings shows a nail having an enlarged flat head, the tool  10  of the present invention can also be used to remove finishing nails, in which case the diameter of nailhead receiving cavity  22  would be slightly larger than the diameter of the head of the finishing nail to be removed.  
         [0041]    A modified form of the tool  10  described above can be used to remove staples from a substrate. The cross-section of the fastener receiving cavity and cutting lip of such a modified tool would be substantially rectangular to conform to the outer perimeter of a staple.  
         [0042]    It will be obvious to those having skill in the art that many changes may be made to the details of the above-described embodiments of this invention without departing from the underlying principles thereof. The scope of the present invention should, therefore, be determined only by the following claims.