Franz Josef Wolf

Sound absorber for sound waves

The broadband surface-like absorber of the invention is used, in particular, for absorbing troublesome airborne noise in the acoustic frequency range. The broadband surface-like absorber, which operates on the Helmholtz resonator principle, is distinguished by a checkerwork of irregular construction, the webs of which are aligned with their narrow sides perpendicular to the principal surface of the perforated plate and the side edges of which are connected in a sound-pressure-resistant and fluidtight manner on the sound side to the rear side of the perforated plate and, on the rear side, to an extended-area cavity boundary aligned with the same orientation as the perforated plate to form differently tuned chamber resonators.

COMPLIANT, ACOUSTICALLY INSULATING TORSIONALLY ELASTIC COUPLING

A compliant, acoustically insulating, torsionally elastic shaft coupling includes a shaft part and a driver part formed by support plates. At least one cage is defined by the support plates which house at least one rubber element of corresponding shape. To achieve an especially compliant torsionally spring characteristic line, the rubber element is formed with uniformly spaced cavities having a cross-section larger than that of hollow ducts centrally crossing a series of these cavities and extending at least essentially over the entire height of the rubber element.