Sound wave attenuation device
AssigneePark Trading Co., Ltd.
InventorsAkira Ochi, Toshihiko Asada
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Abstract
A sound attenuation device is disclosed which is capable of simultaneously attenuating sound waves of both high and low frequencies bands while leaving other frequencies undisturbed. The device is comprised of an outer shell having inlet and outlet apertures at its opposite ends and containing a pair of sound absorbing plates having a pair of thin sheets of a fabric of substantial air permeability and elasticity disposed therebetween and forming an air chamber between the sheets.
Claims20
A sound wave attenuation device having an outer shell with a first end having an inlet aperture and a second end having an outlet aperture and a sound wave attenuation unit contained within the outer shell and between and coaxial with the first and second ends forming a sound wave passageway such that environmental sound waves enter the device through the inlet aperture, penetrate said sound wave attenuation unit wherein sound waves are selectively attenuated and exit the device through the outlet aperture;
- said sound wave attenuation unit comprising:
- (a) a first plate of a sound absorbing material positioned near the inlet aperture and substantially perpendicular to the direction of the sound wave passageway;
- (b) second plate of a sound absorbing material positioned near the outlet aperture and substantially perpendicular to the direction of the sound wave passageway;
- and
- (c) a pair of sheets of a fabric of substantially uniform air permeability and elasticity disposed between said first and second plates and forming an air chamber between said sheets.
An earplug capable of selective sound wave attenuation having a proximal end and a distal end, said earplug comprising:
- (a) a distal member comprising an outer shell having a first end with a first inlet aperture and a second end with a first outlet aperture and a sound wave attenuation unit contained within the outer shell and disposed between and coaxial with the first and second ends forming a distal sound wave passageway such that environmental sound waves enter the device through the first inlet aperture, penetrate said sound wave attenuation unit wherein sound waves are selectively attenuated and exit the distal member through the first outlet aperture;
- said sound wave attenuation unit comprising:
- (i) a first plate of a sound absorbing material positioned near the first inlet aperture and substantially perpendicular to the direction of the distal sound wave passageway;
- (ii) a second plate of a sound absorbing material positioned near the first outlet aperture and substantially perpendicular to the direction of the distal sound wave passageway;
- and
- (iii) a pair of sheets of a fabric of substantially uniform air permeability and elasticity disposed between said first and second plates forming an air chamber between said sheets;
- and
- (b) a hollow proximal member defining a proximal sound wave passageway having:
- (i) a third end with a second inlet aperture substantially adjacent to the first outlet aperture of the second end of the distal member;
- and
- (ii) a fourth end with a second outlet aperture substantially continuous with the proximal sound wave passageway such that the attenuated sound waves exiting the distal member at the first outlet aperture enter the proximal member through the second inlet aperture at the third end and exit the earplug through the second outlet aperture at the fourth end.
Dependencies are inferred from the claim text.