Patents Assigned to Nishiwaki Laboratory
  • Sound attenuating system
    Patent number: 5347585
    Abstract: A sound attenuating system for attenuating sound from a sound source. The system comprises a main conduit through which the sound from the sound source propagates; a first device for defining in the conduit at least one passive acoustic reflecting surface; and a second device for defining in the conduit a plurality of active acoustic reflecting surfaces. The active acoustic reflecting surfaces are of a type which permits a partial permeation of sound therethrough.
    Type: Grant
    Filed: September 10, 1991
    Date of Patent: September 13, 1994
    Assignees: Calsonic Corporation, Nishiwaki Laboratory
    Inventors: Masao Taki, Takuji Mori, Shuntaro Murakami
  • Acoustic conductance and silencer utilizing same
    Patent number: 5257316
    Abstract: An acoustic conductance is formed with oscillatory planes parallel to a duct and disposed on an identical circumference of the duct along a plane intersecting at right angles the duct so that the total area of the oscillatory planes will be substantially more than twice as large as a sectional area of the duct. The acoustic conductance is thereby made less affective on a fluid and provides a pertinent disposition of the acoustic conductance.
    Type: Grant
    Filed: October 24, 1991
    Date of Patent: October 26, 1993
    Assignees: Matsushita Electric Works, Ltd., Nishiwaki Laboratory
    Inventors: Hiroaki Takeyama, Masao Taki, Takuji Mori