Patent ID: 7708113
Filing Date: 2010-05-04
Classification: F01N,F02B,F02M,F04C

Abstract:
1. A variable frequency sound attenuation device comprising: a central portion rotatable about a first axis; a radial portion extending outwardly from the central portion; a chamber defined by the radial portion having a closed first end and a second end opening outwardly of the radial portion; a second axis defined by the chamber and having a radial component thereto; a piston disposed within the chamber for movement along the second axis in response to a centrifugal force imparted on the piston by rotation of the central portion and the radial portion about the first axis; a biasing member having a first end fixed within the chamber and a second end fixed to the piston to limit movement of the piston along the second axis; and a variable length quarter wave chamber defined by the chamber, the second, open end of the chamber and the piston and having a variable frequency, sound attenuating length defined by the location of the piston along the second axis of the chamber.