Patents by Inventor Melvin J. Hargraves

Melvin J. Hargraves 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).

  • Control valve having integral visual indicator for fluid safety systems
    Patent number: 4194529
    Abstract: A control valve structure and combined visual indicator for controlling fluid and visually indicating the operating condition of a portion of a fluid system. The control valve has a slide valve mounted in a housing and biased toward a retracted position with one end portion thereof extending from the housing. The extended end portion of the slide valve has a knob adapted to be manually gripped for moving of the slide valve outwardly for setting same. A visual indicator is mounted on the knob. A port in the housing communicates with the slide valve to permit the application of fluid pressure to the slide valve to move same outwardly. The visual indicator has a visually observable indicator member movable between two positions for indicating the presence of either of two associated conditions in a system containing the control valve.
    Type: Grant
    Filed: September 21, 1978
    Date of Patent: March 25, 1980
    Assignee: W-K-M Wellhead Systems, Inc.
    Inventors: Melvin J. Hargraves, Clifford M. Peters
  • Control valve having integral visual indicator for fluid safety systems
    Patent number: 4137942
    Abstract: A control valve structure and combined visual indicator for controlling fluid and visually indicating the operating condition of a portion of a fluid system. The control valve has a slide valve mounted in a housing and biased toward a retracted position with one end portion thereof extending from the housing. The extended end portion of the slide valve has a knob adapted to be manually gripped for moving of the slide valve outwardly for setting same. A visual indicator is mounted on the knob. A port in the housing communicates with the slide valve to permit the application of fluid pressure to the slide valve to move same outwardly. The visual indicator has a visually observable indicator member movable between two positions for indicating the presence of either of two associated conditions in a system containing the control valve.
    Type: Grant
    Filed: July 15, 1976
    Date of Patent: February 6, 1979
    Assignee: W-K-M Wellhead Systems, Inc.
    Inventors: Melvin J. Hargraves, Clifford M. Peters