Patents Assigned to K.K. Fujita Shoten
  • Speaker edge
    Patent number: 3980841
    Abstract: An acoustic material suitable for use as a speaker edge comprises an expanded plastic and minute collagen fibers wherein the content of the collagen fibers is 15 - 40% based on the weight of the expanded plastic and the length of the fibers is equal to or less than 1 mm.
    Type: Grant
    Filed: May 23, 1975
    Date of Patent: September 14, 1976
    Assignees: K.K. Fujita Shoten, Hisao Sato
    Inventors: Hiroshi Okamura, Hisao Sato, Isamu Iwasaki