Patent ID: 6439319
Filing Date: 2002-08-27
Classification: E21B

Abstract:
A drill head for an apparatus for directional boring comprising:a bit including a bit shaft; a holder for a device for detecting angular orientation of the bit; a hammer including a housing and a striker for delivering impacts to the bit shaft, which bit shaft is mounted for sliding movement in a front end opening of the hammer housing and wherein the bit assembly, holder and hammer are connected head to tail with the bit at a front end; and the bit further comprising a frontwardly facing main cutting surface having a plurality of main cutting teeth disposed thereon and a gage tower extending radially outwardly from the main cutting surface, which gage tower has at least one frontwardly facing gage cutting tooth thereon suitable for cutting over an angle defined by less than a full rotation of the bit, and wherein the device for detecting angular orientation is in a predetermined alignment with the gage tower so that it determines the orientation of the gage tower relative to the axis of rotation of the drill head.