Patents by Inventor Elmer J. Volmert

Elmer J. Volmert 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).

  • Hydraulic jar
    Patent number: 5174393
    Abstract: There are disclosed alternate embodiments of a double acting hydraulic jar having a single detent chamber having a restriction on the inner diameter of its outer tubular member through which detent means carried about the outer diameter of the inner tubular member may be moved in order to impart either an up or down jar.
    Type: Grant
    Filed: July 2, 1991
    Date of Patent: December 29, 1992
    Assignee: Houston Engineers, Inc.
    Inventors: Billy J. Roberts, Elmer J. Volmert, Arthur W. Meeks