Patents by Inventor Keith W. Sheffield

Keith W. Sheffield 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).

  • Prescription lens attachable to safety glasses
    Patent number: 5608470
    Abstract: A prescription lens attachable to a safety glass frame. The safety glass frame is provided with a single lens, a center cross pin and indentation on an inner surface of the safety glass frame juxtaposed the temple pivot pin. A prescription frame includes separate prescription lenses and a central clip that clips onto the cross pin of the safety glass frame. The outer ends of the prescription frame are provided with angular locking ends that are pressed into the indentation on the safety glass frame. Thus, the prescription lens frame is held securely onto the safety glass frame between the safety glass frame and the persons eyes. Damage to the safety glass lens or frame necessitate replacement of only the non-prescription safety glasses because the prescription frame can be removed from the damaged frame and secured to a new safety glass frame.
    Type: Grant
    Filed: June 26, 1995
    Date of Patent: March 4, 1997
    Assignee: Crews, Inc.
    Inventor: Keith W. Sheffield
  • Prescription lens attachable to safety glasses
    Patent number: 5428407
    Abstract: A prescription lens attachable to a safety glass frame. The safety glass frame is provided with a single lens, a center cross pin and indentation on an inner surface of the safety glass frame juxtaposed the temple pivot pin. A prescription frame includes separate prescription lenses and a central clip that clips onto the cross pin of the safety glass frame. The outer ends of the prescription frame are provided with angular locking ends that are pressed into the indentation on the safety glass frame. Thus, the prescription lens frame is held securely onto the safety glass frame between the safety glass frame and the persons eyes. Damage to the safety glass lens or frame necessitate replacement of only the non-prescription safety glasses because the prescription frame can be removed from the damaged frame and secured to a new safety glass frame.
    Type: Grant
    Filed: December 15, 1993
    Date of Patent: June 27, 1995
    Inventor: Keith W. Sheffield
  • Safety glasses and prescription lens insert combination
    Patent number: D372490
    Type: Grant
    Filed: June 20, 1995
    Date of Patent: August 6, 1996
    Assignee: Crews, Inc.
    Inventors: Keith W. Sheffield, John Chin