Abstract:
A fastener is provided. The fastener includes an elongated shank extending along a longitudinal axis. The shank has a first end and a second end and a head portion is formed at the first end of the shank. The head portion includes an annular flange extending radially out from the longitudinal axis and has a first diameter. The fastener also includes a first section extending along at least a portion of the shank and disposed adjacent to the head portion. The fastener also includes a knurled section extending along at least a portion of the shank and disposed adjacent to the first cylindrical section where the knurled section includes a plurality of longitudinally extending grooves and peaks disposed around a circumference of the shank and a helical thread portion extending axially along at least a portion of said shank and disposed adjacent to the knurled section.

Description:
RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 61/699,033, filed Sep. 10, 2012, which is incorporated by reference herein in its entirety 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to fasteners. In particular, the present invention relates to a drive spike for driving into a substrate and preventing inadvertent removal of the drive spike from the substrate. 
     BACKGROUND 
     Many types of fasteners are known in the art for firmly holding a variety of components together. For example, railroad drive spikes are used to hold steel rails to wooden ties. Drive spikes may also be used to hold together bridges, trestles, wooden piers, and docks. 
     Typically, for railways, the steel rails have mounting flanges adapted to mate with metallic plates. The metallic plates also contact the wooden ties and are adapted receive drive spikes to secure the rails to the ties. The spikes are inserted through openings or recesses in the metal plate and driven into the wooden ties. Thus, the steel rails are secured to the wooden ties via the metal plates and the drive spikes. 
     In use, the drive spikes eventually loosen from the wooden ties as a result of events such as repeated train crossings and environmental conditions. The weight and vibrations from the passing trains cause the spikes to loosen and enlarge the entry holes within the wooden ties. Environmental conditions such as humidity, temperature changes, rain, snow, etc. may also cause the drive spikes to become loosed within the wooden ties. Additionally, vandals may purposely loosen or remove the drive spikes. As the drive spikes become loose, the holes into which the drive spikes are inserted in the wooden ties enlarge. The enlarged holes then become further exposed to environmental conditions, causing the wood to decay more quickly. 
     Tightening or replacement of the drive spikes is often difficult and costly. Removal of a drive spike may cause further destruction to the wooden tie making the replacement of the drive spike nearly impossible. Once the drive spike is loosened and or the wood becomes damaged, the entire wooden tie often requires replacement in order to provide a steel rail that is securely fastened to the wooden tie. 
     Similar to the railway example, the bridge, trestle, pier and dock drive spike connections are also subject to vibrational and environmental stresses, as well as vandalism, that cause unwanted loosening of the drive spikes within the substrate. Once the drive spike loosens, the substrate into which the spike is driven usually must be replaced in order to securely fasten the bridge, trestle, etc. to the substrate. Replacement of the drive spike itself is generally insufficient to securely fasten objects to the substrate. The enlarged hole in the substrate causes the substrate to become more quickly degraded and thus prevents the drive spike from securely gripping the substrate. 
     Therefore, it is an object of the present invention to provide a drive spike that securely fastens an object to a substrate, such as wood, and prevents inadvertent loosening or removal of the drive spike from the substrate, thus further reducing the requirement for replacement of the substrate due to damage caused by the insecure fastening of an object to a substrate. 
     BRIEF SUMMARY 
     In order to alleviate one or more shortcomings of the prior art, a drive spike is provided herein. 
     A fastener is provided. The fastener includes an elongated shank extending along a longitudinal axis. The shank has a first end and a second end and a head portion is formed at the first end of the shank. The head portion includes an annular flange extending radially out from the longitudinal axis and has a first diameter. The fastener also includes a first section extending along at least a portion of the shank and disposed adjacent to the head portion. The fastener also includes a knurled section extending along at least a portion of the shank and disposed adjacent to the first cylindrical section where the knurled section includes a plurality of longitudinally extending grooves and peaks disposed around a circumference of the shank and a helical thread portion extending axially along at least a portion of said shank and disposed adjacent to the knurled section. 
     Advantages of the present invention will become more apparent to those skilled in the art from the following description of the preferred embodiments of the invention which have been shown and described by way of illustration. As will be realized, the invention is capable of other and different embodiments, and its details are capable of modification in various respects. Accordingly, the drawings and description are to be regarded as illustrative in nature and not as restrictive. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side elevational view of an embodiment of a fastener in accordance with the present invention; 
         FIG. 2  is a side elevational view of an embodiment of a fastener in accordance with the present invention; 
         FIG. 3  a top plan view of  FIG. 1 ; 
         FIG. 4  is a sectional view through line A-A of  FIG. 2 ; and 
         FIG. 5  is a sectional view through line B-B of  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION 
     An embodiment of the present invention is shown in  FIG. 1  as a fastener in the form of a drive spike  10 . The lengths and diameters of the fastener  10  described herein are meant to be non-limiting examples and may be varied as will be understood by one of skill in the art. 
     The fastener  10  includes an elongated shank  20 , a head  22  at a first end portion  24  of the shank  20  and a tip  26  at a second end portion  28  of the shank  20 . The tip  26  may be any shape, including blunt and pointed. The fastener  10  has a longitudinal axis  30  extending from the first end portion  24  to the second end portion  28 . 
     The head  22  further comprises an annular flange  32  that extends radially from the shank  20 . The annular flange  32  may include a dome-shaped upper surface  34  and a flattened lower surface  35  that extends radially beyond the shank  20 . The head  22  may further comprise a protrusion  36  that extends from the first end portion  24  of the shank  20 . The protrusion  36  may be hemispherical in shape and adapted to be engaged by a striking tool to drive the fastener  10  into a substrate S. The protrusion  36  is adapted to receive significant force and is further adapted to deform as a result of the striking force. 
     The head  22  also comprises an outer surface  38  adapted to be engaged by a gripping tool such as a wrench or a socket that may be used to apply torque to the fastener  10  to drive the fastener  10  into the substrate S. In some embodiments, the outer surface  38  may be polygonally shaped. However, the outer surface  38  may be any shape that may be used with a variety of tools. Alternatively, the outer surface  38  does not need to be engaged to drive the fastener  10  into the substrate S. For example, a hole may be pre-drilled in the substrate S and the fastener  10  may be driven into the substrate S using a striking tool to strike the protrusion  36  of the head  22  and thereby insert the fastener  10  into the substrate S. As described below, additional features of the fastener  10  facilitate insertion of the fastener  10  into the substrate using a driving force. A top view of an embodiment of the head  22  of the fastener  10  is shown in  FIG. 3 . By way of non-limiting example, the head  22  may have a square cross sectional shape having sides extending radially outwardly from the longitudinal axis. Each side may extend about 0.75 to about 0.81 inches in some embodiments. 
     As shown in  FIGS. 1 and 2 , the annular flange  32  extends radially from the longitudinal axis  30  of the fastener  10 . In some embodiments, the annular flange  32  extends beyond the circumference of the shank  20 . As shown in  FIGS. 1 and 2 , the annular flange  32  has a diameter D 1  that is greater than a diameter D 2  of a threaded portion of the shank  20  (described below). In some embodiments, the fastener  10  further includes a first section  40  adjacent to the flange  32 . The first section  40  may be cylindrically shaped and have a smooth surface. The first section  40  may also be polygonally shaped or may include one or more flattened sides. In some embodiments, the first section  40  is positioned directly adjacent to the flange  32 . The first section  40  includes an abutment surface  41  positioned apart from the flange  32 . The abutment surface  41  is configured to abut the substrate S into which the fastener  10  is driven so that the first portion  40  is positioned above the substrate S when the fastener  10  has been driven into the substrate S. The first section  40  has a diameter D 3  that is less than the diameter D 1  of the annular flange  32  and greater than the diameter D 2  of the shaft. By way of non-limiting example, the diameter D 1  may be about 1.75 inches, the diameter of D 2  may be about 0.937 inches ( 5/16) and the diameter of D 3  may be about 1.25 inches. The first section  40  may be sized and shaped to receive a tool (not shown) to remove the fastener  10  from the substrate S. The smaller diameter D 3  of the first section  40  relative the diameter D 1  of the annular flange  32  allows the tool to contact the lower surface  35  of the annular flange  32  that is positioned above the substrate S so that the tool can pull the fastener  10  out of the substrate S. A length L 1  of the first section  40  may be provided so that the tool fits between the substrate S and the lower surface  35  of the annular flange  32 . By way of non-limiting example, the length L 1  may be about 0.375 inches. 
     As shown in  FIGS. 1 and 2 , the fastener  10  may also include a second section  44  adjacent to the first section  40  so that the first section  40  is between the flange  32  and the second section  44 . The second section  44  may be cylindrically shaped and have a smooth surface. The second section  44  may also be polygonally shaped or may include one or more flattened sides. In some embodiments, the second section  44  is positioned directly adjacent to the first section  40 . The second section  44  has a diameter D 4  that is less than the diameters D 1  and D 3 . In some embodiments, the diameter D 4  is substantially the same as the diameter D 2  of the shank  20 . By way of non-limiting example, the diameter D 4  may be about 0.937 inches. The second section  44  is configured to be positioned within the substrate S. A length L 2  of the second section  44  may be about 1.125 inches. 
     The shank  20  may also include a knurled section  46  adjacent to the second section  44 . The knurled section  46  may be cylindrically shaped and may include a plurality of axial grooves  48  and peaks  49  as shown in the cross sectional view in  FIG. 4 . In some embodiments, the peaks  49  may include a leading edge. In some embodiments, the knurled section  46  is directly adjacent to the second cylindrical section  44 . The knurled section  46  is configured to allow the fastener  10  to be driven into the substrate S and to resist removal for the fastener  10  from the substrate S. The knurled section  46  has a diameter D 5  measured at the peaks  49  that is slightly larger than the diameters D 2  and D 4  and less than the diameter D 3 . By way of non-limiting example, the diameter D 5  may be about 0.969 inches and a length L 3  of the knurled section may be about 0.5 inches. For the knurled section  46  having a diameter D 5  of about 0.969 inches, the number of peaks  49  is greater than 40. The peaks  49  may all be equal in size and shape extending around the shank  20 . In some embodiments, the depth of the grooves  48  may be about 0.025 inches to about 0.035 inches. In some embodiments, the peaks  49  extend substantially parallel to the longitudinal axis of the shank  20 . 
     The shank  20  also includes a transition section  52  extending between the knurled section  46  and a threaded section  54 . The transition section  52  tapers inward from the knurled section  46  to the threaded section  54  so that threads  56  can be rolled on the threaded section  54 . The transition section may be less than about 0.1 inch. 
     The shank  20  also includes the threaded section  54  that includes one or more threads  56 . In some embodiments the threads  56  may be helical fluted threads as shown in  FIG. 1 . The threads  56  extend from the transition section  52  to about the tip  26  of the shank  20 . The angle at the end of the threads  56  may be about 40° to about 50°, more preferably about 45°. In some embodiments, the threaded section  54  may include 4 fluted threads  56 . As shown in  FIG. 5 , in some embodiments, a width  62  of each helical turn of the thread  56  is about 0.5 inches, although any width may be used. In some embodiments, a depth  64  of the thread  56  protruding from the shank  20  is about 0.125 inches, although any depth may be used with the present invention. 
     In some embodiments, a length L 4  of the head  22  and the first section  40  and the protrusion  36  is about 1.375 inches. The protrusion  36  extends about 0.125 inches above the head  22 . The length L 4  represents the length that is positioned above the substrate S. A length L 5  of the shank  20  from the second section to the tip  26  is about 6.5 inches. The length L 5  represents the length of the fastener  10  that is inserted into the substrate S. In some embodiments, the length of the fastener  10  may be about 7.75 inches and the knurled section  46  maybe about 1/15 of the length. In some embodiments, the knurled section  46  may be spaced about 1.125 inches from the first section  40 . Other lengths and diameters for each of the dimensions described herein may be used and remain within the scope of the invention. 
     In some embodiments, the fastener of the present invention comprises a metal, more preferably iron or steel, most preferably carbon steel, for example C1035. Any material suitable for forming and having sufficient strength for the fastener of the present invention may be used as will be understood by one of skill in the art. 
     Although the invention herein has been described in connection with a preferred embodiment thereof, it will be appreciated by those skilled in the art that additions, modifications, substitutions, and deletions not specifically described may be made without departing from the spirit and scope of the invention as defined in the appended claims. It is therefore intended that the foregoing detailed description be regarded as illustrative rather than limiting, and that it be understood that it is the following claims, including all equivalents, that are intended to define the spirit and scope of this invention.