Patents by Inventor Keith T. Lambell

Keith T. Lambell 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: 4850016
    Abstract: A noise cancelling microphone for location inside an apertured mouthpiece region of a telephone handset comprises a housing with a face for securement in contact with the inside of the mouthpiece region. A cavity accommodates a vibratable diaphragm. A first sound path is provided to a front surface of the diaphragm by way of an opening in a central region of the face of the housing and apertures in a central portion of the mouthpiece region of the handset. A second sound path, physically separated from the first, is provided to a rear surface of the diaphragm by way of an opening in an outer region of the face of the housing and apertures in an outer portion of the mouthpiece region. The separated sound paths are extended by securing an upstanding member, such as a hollow truncated cone, externally on the mouthpiece region to separate the central and outer apertures.
    Type: Grant
    Filed: January 29, 1988
    Date of Patent: July 18, 1989
    Assignee: Crystalate Electronics Limited
    Inventors: Ronald J. Groves, Keith T. Lambell