Patents Represented by Attorney W. E. Johnson, Jr.
  • Patent number: 4393598
    Abstract: A surface activated multishot survey tool utilizes a dampened magnetic compass movably positioned within a probe to determine the direction of a borehole. Lamps in the probe are operable to light the face of the compass. A lens projects the image of the compass onto a movable film strip. An electrical cable is connected to the probe and is used to pass a current to the lamps and provide selective operation of the tool from the surface of the borehole. Electrical connectors are provided at each end of the probe so that the probe may be inverted within the borehole to accommodate surveys in which the angle of the borehole is greater than that at which the compass will operate without error. Because connectors are located at both ends of the probe, electrical current passes around the magnetic compass, thus creating a magnetic field about the compass.
    Type: Grant
    Filed: April 19, 1982
    Date of Patent: July 19, 1983
    Assignee: NL Sperry Sun, Inc.
    Inventors: Steven W. Powell, James G. Stockton