Patents by Inventor William H. Purdy

William H. Purdy 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: 5218388
    Abstract: A motion picture film monitor structured and operated in the film path of a film projector, having a plurality of film support rollers for supporting the film as it passes adjacent a plurality of sensors. The plurality of sensors includes at least one proximity sensor positioned preferably adjacent one of the guide rollers and when more than one proximity sensor is spaced closely to each other, a different frequency is used by each proximity sensor. In addition, an optical film presence detector including a light emitter and a light sensor is positioned adjacent another support roller such that when the film passes the film presence detector, it is supported by the roller. A film motion detector using a similar optical system is positioned adjacent one of the support rollers which supports the film in close proximity to the sensor. Electronic circuitry and connections therefore, are structured to allow for a logically configured and miniaturized monitor.
    Type: Grant
    Filed: June 21, 1991
    Date of Patent: June 8, 1993
    Inventor: William H. Purdy