Rail anchoring spike

Abstract

An improved fastener for attaching metal to wood is described. The fastener is particularly suited for use as a railroad spike for attaching a metal rail to a wooden tie. The improved spike is adapted for installation by either driving or screwing the spike into the tie. A plurality of flutes are adapted to engage with the tie, thereby preventing loosening of the spike. The spike may be used with or without a metal boss or fishplate to secure a metal rail to a wooden tie.

1 . A metal to wood fastening spike, comprising: 
 (a) a head having an annular flange;    (b) a stand-off extending axially from said flange;    (c) at least one flute axial to said stand-off, said flute adapted to engage wood; said stand-off having a length adapted to ensure that said flute is at least partially embedded in wood when said spike is used to fasten metal to wood;    (d) a shank extending axially from said flutes to form a tapered tip, said shank comprising an outer diameter and further comprising a plurality of helical, generally parallel threads extending over at least a portion of said shank between said flute and said tip, wherein said outer diameter of said shank tapers to a point.    
   
   
       2 . A spike according to  claim 1  comprising a plurality of flutes.  
   
   
       3 . A spike according to  claim 1  comprising first and second annular flanges.  
   
   
       4 . A spike according to  claim 1 , wherein said threads extend to said point of said tapered tip.  
   
   
       5 . A metal to wood fastening spike, comprising: 
 (a) a head having an annular flange;    (b) a stand-off extending axially from said flange;    (c) at least one flute axial to said stand-off, said flute adapted to engage wood; said stand-off having a length adapted to ensure that said flute is at least partially embedded in wood when said spike is used to fasten metal to wood;    (d) a shank extending axially from said flutes to form a tapered tip, said shank having a first diameter and comprising a plurality of helical, generally parallel threads wherein each of said threads extends over at least a portion of said shank between said flute and said tip and each of said threads comprises at least one discontinuity having a diameter less than said first diameter.    
   
   
       6 . A spike according to  claim 1  wherein said discontinuities are aligned to create a circumferential channel in said shank.  
   
   
       7 . A spike according to  claim 1  wherein said discontinuities are aligned to create an axial channel in said shank.