Drill tip for foundation pile

Abstract

An improved drill tip for a foundation pile comprises a frustro-conical upper section, a cylindrical middle section, and a generally conical lower section, all disposed in coaxial alignment about a center axis, the upper section for attachment to a foundation pile, and having a bottom edge diameter smaller than a top edge diameter and an upper helical flight having a radial extent less than the top edge diameter, the middle section extending from the bottom edge of the upper section and having approximately the same diameter as the bottom edge diameter, and the lower section extending from a lower edge portion of the middle section and having a plurality of symmetrically disposed helical fins having a radial extent less than the bottom edge diameter, the lowermost portion of the fins extending freely below the conical main body of the lower section in a configuration resembling a swiveling fishtail.

1 . A drill tip for a foundation pile, the drill tip comprising:
 a frustro-conical upper section having a top edge and a bottom edge, said top edge for attachment to the foundation pile, said top edge having a top edge diameter, said bottom edge having a bottom edge diameter smaller than said top edge diameter, and said upper section having an upper helical flight having a radial extent generally no greater than said top edge diameter,   a cylindrical middle section extending from said bottom edge and having approximately the same diameter as said bottom edge diameter, and   a generally conical lower section extending from said lower edge portion of said middle section, said upper, middle and lower sections disposed in coaxial alignment about a center axis.   
     
     
         2 . The drill tip for a foundation pile of  claim 1  wherein:
 said middle section has a lower edge portion and a middle helical flight having a radial extent generally no greater than said top edge diameter. 
 
     
     
         3 . The drill tip for a foundation pile of  claim 2  wherein:
 said lower section has a generally conical main body and a plurality of symmetrically disposed helical fins having a radial extent generally no greater than said bottom edge diameter, a lowermost portion of each said fin extending freely below said conical main body forming a plurality of blades resembling a swiveling fishtail.