Patents by Inventor Alf Ivarsson

Alf Ivarsson 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 measuring and registering of sound
    Patent number: 4003264
    Abstract: A device is shown for detecting and recording the presence of sound above specified predetermined levels during given time intervals. The circuit includes a microphone, a filter, an amplifier, level detectors, light emitting diodes and a photosensitive material.
    Type: Grant
    Filed: October 21, 1975
    Date of Patent: January 18, 1977
    Assignee: Shine Patent AB
    Inventors: Bengt Erlandsson, Hakan Hakansson, Bengt Salen, Per Nilsson, Alf Ivarsson