1
Michael F Gard, Jian Jin, John C Wisehart: Electronic compass. The Charles Machine Works, Sidley & Austin, December 15, 1998: US05850624 (130 worldwide citation)

An electronic compass (10) for use in a boring tool (12) which will provide an orientation of the boring tool relative to the earth's magnetic field. In addition, a more straightforward left or right deviation from an initial bearing can be determined. The invention can correct for pitch angle and r ...


2
Alan J Rider: System transmitting and receiving digital and analog information for use in locating concealed conductors. The Charles Machine Works, Richards Medlock & Andrews, November 23, 1993: US05264795 (103 worldwide citation)

An improved locator system is provided which transmits digital and analog information over an electromagnetic field that is radiating from an underground source. The locator system includes a transmitter that modulates its output signal by turning its output signal on and off in response to a sequen ...


3
Alan J Rider, Lester R Querry: System for locating multiple concealed underground objects. The Charles Machine Works, Richards Medlock & Andrews, November 1, 1994: US05361029 (96 worldwide citation)

An improved locator system is provided which simultaneously couples a number of different frequency signals to a number of concealed underground conductive lines, for the purpose of locating and distinguishing between the underground lines. The locator system includes a transmitter which generates t ...


4
Alan J Rider, Lester R Querry: Locator transmitter having an automatically tuned antenna. The Charles Machine Works, Richards Medlock & Andrews, July 27, 1993: US05231355 (89 worldwide citation)

The present invention generally relates to a system for use in determining the location and orientation of concealed underground objects and, more particularly, to an improved locator system having a unique and improved interface with an operator. In accordance with one embodiment of the invention, ...


5
Lloyd N Salsman, Leslie D Hoy: System for locating concealed underground objects using digital filtering. The Charles Machine Works, Banner Birch McKie & Beckett, November 12, 1991: US05065098 (80 worldwide citation)

A locating system has its performance enhanced by the use of digital filtering. The locating system may include a transmitter for transmitting an electromagnetic signal from a concealed object. The locating system may also use electromagnetic signals from existing electromagnetic sources unrelated t ...


6
Michael F Gard, Jian Jin: System and method for determining orientation to an underground object. The Charles Machine Works, McKinney & Stringer PC, June 25, 2002: US06411094 (75 worldwide citation)

A system and method use magnetic field sensing to detect underground objects for strike avoidance. The system detects magnetic field components for both passive distortions in the magnetic field indicative of a ferromagnetic object and active magnetic fields that are impressed on an object by a sign ...


7
Gregory W Draper, Frank S Nickel, Michael F Gard, Jian J Jin: Avoiding ghosting artifacts during surface location of subsurface transmitters. The Charles Machine Works, Sidley & Austin, April 15, 1997: US05621325 (59 worldwide citation)

An apparatus and method is provided for determining if the signal received from an underground beacon (10) at a locator (22) is a true signal or a ghost signal. Orthogonal horizontal antenna (38) and vertical antenna (40) are used and a ratio is computed of the signal strengths measured by the two a ...


8

9
Matthew L Dock, Brent G Stephenson: Downhole generator for horizontal directional drilling. The Charles Machine Works, McKinney & Stringer P C, January 6, 2004: US06672409 (51 worldwide citation)

A generator assembly for generating power in the downhole end of a drill string used to form a borehole in horizontal directional drilling. The drill string provides a fluid passageway in which the downhole generator is receivingly disposed, at least in part, to subject a rotatable turbine to a pres ...


10
Richard P Dunn: Method of and apparatus for drilling a horizontal controlled borehole in the earth. The Charles Machine Works, Banner Birch McKie & Beckett, September 4, 1990: US04953638 (47 worldwide citation)

A method of boring a hole in the earth such as for passing under obstacles, not limited, but including roadways, rivers, dikes, canals or other inexcessible areas where it is impossible to trench a ditch including the steps of advancing a rotating drill string in a direction inclined to the earth's ...