Patents by Inventor Rhys M. Evans

Rhys M. Evans has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Automatic force control for a seismic vibrator
    Patent number: 4692912
    Abstract: The present invention provides a method and apparatus for controlling the response of a seismic vibrator during its actuation period. The sweep input signal is modified in response to an average of the force applied to the earth by the vibrator over at least one cycle of the sweep signal. Additionally, this modified drive signal may be further adjusted by selective adjustment of the amplitude of the signal within selected frequency ranges.
    Type: Grant
    Filed: November 30, 1984
    Date of Patent: September 8, 1987
    Assignee: Geosource, Inc.
    Inventors: Allan H. Mueller, Dean P. Perkins, Rhys M. Evans