Patent ID: 6756784
Filing Date: 2004-06-29
Classification: E21B,G01C,G01V

Abstract:
In producing an underground boring tool having a drill head configured for allowing the transmission of a ground penetrating locating signal, a method comprising the steps of:providing an elongated electrically conductive wall arrangement, as part of said drill head for direct contact with the ground, including a pair of opposing ends to at least partially bound an interior chamber formed between said opposing ends, said wall arrangement further extending in an elongation direction between the opposing ends; positioning a transmitter in said interior chamber for originating said locating signal such that transmission of the locating signal by the transmitter induces a current flow in said wall arrangement, resulting in a counter magnetic field originating from the wall arrangement, upon transmission of the locating signal; and forming a number of elongated slots in said wall arrangement including at least two elongated slots which are arranged at least generally in said elongation direction and spaced apart about said wall arrangement, each slot having a width that is just wide enough to disrupt said current flow, thereby reducing the counter magnetic field and said number of said slots is formed based, at least in part, on said locating signal exhibiting a signal strength that is substantially independent of roll orientation of the boring tool.