Patents by Inventor Alfred E. W. Fletcher

Alfred E. W. Fletcher 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).

  • Device for steering a drilling tool and/or drill string
    Patent number: 4947944
    Abstract: An outer tube (26) provided with rolling bearings (28) is rotatably mounted on an inner tube (10) which can be connected to a drilling tool or a pipe string. Radially mobile guiding rails are arranged in longitudinal channel-like recesses on the outer surface of the outer tube (26). Belleville springs lodged in spring housings (36) arranged in recesses in the guide rails (35) press against the outer tube (26) and force the guide rails (35) radially outward. The guide rails (35) help prevent rotation of the outer tube, enable it to slide longitudinally in the bore, and guide the inner tube (10) mounted in the outer tube (26) and the drilling tool or pipe string attached to the inner tube (10).
    Type: Grant
    Filed: February 15, 1989
    Date of Patent: August 14, 1990
    Assignee: Preussag Aktiengesellschaft
    Inventors: Trevellyn M. Coltman, Alfred E. W. Fletcher, Bernhard Prevedel