Patents by Inventor Herschel E. Zirger

Herschel E. Zirger 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).

  • Releasable overshot
    Patent number: 5054833
    Abstract: A releasable overshot having independent slips, for retrieval of downhole tools and other equipment, which can be operated with a wireline, tubing, coiled tubing, or drill pipe string.
    Type: Grant
    Filed: November 26, 1990
    Date of Patent: October 8, 1991
    Assignee: Herschel E. Zirger
    Inventors: Thomas R. Bishop, Herschel E. Zirger