Patents by Inventor John Rolker

John Rolker 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).

  • Patent number: 5398145
    Abstract: Tracking control apparatus includes a magnetic recording medium (disk or tape) comprising a dedicated servo track having recorded thereon a servo signal having a fixed spatial wavelength, and magnetic playback apparatus comprising a servo tracking head having an elongated tapered transducing gap transverse to the dedicated servo track. The transducing gap has (1) a relatively small magnetic gap length, at a first end of the gap, which is less than the spatial wavelength of the recorded signal, and (2) a relatively large magnetic gap length, at a second opposing end of the gap, which is greater than the spatial wavelength of the recorded servo signal. The servo head is in a desired tracking position when the segment of the tapered gap aligned with the servo track has a magnetic gap length that is equal to the spatial wavelength of the servo signal.
    Type: Grant
    Filed: May 5, 1994
    Date of Patent: March 14, 1995
    Assignee: Eastman Kodak Company
    Inventors: Frederick J. Jeffers, John Rolker