Patents by Inventor William D. Hardgrave

William D. Hardgrave 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).

  • Actuator for wireline blowout preventer
    Patent number: 4214605
    Abstract: Disclosed is an hydraulic actuator for a wireline blowout preventer. The actuator uses well pressure to effect closure of the blowout preventer and hydraulic control fluid to open the blowout preventer.
    Type: Grant
    Filed: January 11, 1978
    Date of Patent: July 29, 1980
    Assignee: Otis Engineering Corporation
    Inventor: William D. Hardgrave