Acoustics – Sound-modifying means – Housing or enclosure
Reexamination Certificate
1999-12-10
2001-06-12
Nappi, Robert E. (Department: 2837)
Acoustics
Sound-modifying means
Housing or enclosure
C181S202000, C181S203000
Reexamination Certificate
active
06244377
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a machinery sound absorbing apparatus, and more particularly, to a machinery sound absorbing apparatus which can absorb machinery sound generated from a large-sized machine such as a power press and a metal cutting machine.
2. Description of the Related Art
A plurality of large-sized machines are arranged in a factory. Such machines are generating sources of machinery sound. In this case, it is desirable to avoid that the machinery sound is generated from the plurality of generating sources at the same time. Especially, it is desirable to absorb a large volume of machinery sound generated from the large-sized machine such as a power press, a metal cutting machine, and an injection molding machine.
It is well known to provide a machinery sound absorbing board. As the machinery sound absorbing board, there are known various boards such as a wave-shaped plate, a wall board having a lot of projections, and a machinery sound absorbing board having a porous surface. These boards are provided for the generating source of the machinery sound whose position is not defined. When the position of the generating source of the machinery sound is defined, these boards such as a wave-shaped plate, a wall board having a lot of projections, and a machinery sound absorbing board having a porous surface are not the most appropriate.
It is desirable to most appropriately absorb the machinery sound generated from the machinery sound generating source which the position is fixed. Also, it is desirable that a quantity of reflected wave is less.
In conjunction with the above description, a sound absorbing and shielding apparatus is disclosed in Japanese Laid Open Utility Model Application (JPU-A-Showa 57-172499). In this reference, the sound absorbing and shielding apparatus has a substrate (
1
) and an sound absorbing material (
2
) connected to the substrate (
1
) on one side and having a saw-tooth shape on the other side.
Also, an elastic surface wave filter is disclosed in Japanese Laid Open Patent Application (JP-A-Showa 57-127321). In this reference, an input transducer, an output transducer and a sound absorbing film for absorbing an unnecessary wave are provided on a piezo-electric plate. The sound absorbing film has an obliquely deep cutting portion on the back side of the transducer.
Also, a sound absorbing material is disclosed in Japanese Laid Open Utility Model Application (JPU-A-Showa 59-186308). In this reference, a lot of tapered holes are provided on at least one of surfaces of a foamed synthetic resin to have a sharp tip to the inner direction.
Also, a sound absorbing structure is disclosed in Japanese Laid Open Utility Model Application (JPU-A-Showa 63-71211). In this reference, the sound absorbing structure is formed of a water repellent material and a cavity having a cone cross section such that a sound wave entering from an opening portion is absorbed, interfered with each other, and converged and then attenuated.
Also, a sound erasing apparatus is disclosed in Japanese Laid Open Patent Application (JP-A-Heisei 9-212175). In this reference, a sound passes through a position on a propagation path and a reflection of the sound also passes through the position. The sound and the reflection are interfered with each other by use of a phase difference between them to attenuate them. A structure (
2
) has a curved surface which is formed from a part of a spherical surface, as a part of an internal closed space. A sound input section (
3
) has a terminate (
6
) on a center position P
0
of the sphere in the structure (
2
).
Also, a fluid circulated tank is disclosed in Japanese Laid Open Patent Application (JP-A-Heisei 10-9999). In this reference, a sound absorbing room (
2
) is provided at a corner section (
1
e
) of a fluid circulated tank (
1
) and is filled with the same fluid as the tank (
1
). An interface between the tank (
1
) and the sound absorbing room (
2
) is formed of sound transmitting material (
2
a
). The inside of the sound absorbing room (
2
) is separated by sound absorbing material (
2
b
), and the inside surface of the sound absorbing room (
2
) is covered with a saw-tooth shaped sound absorbing material (
2
c
).
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to provide a machinery sound absorbing apparatus which can most appropriately absorb a machinery sound generated from a machinery sound generating source whose position is fixed.
Another object of the present invention is to provide a machinery sound absorbing apparatus which can most appropriately absorb a machinery sound generated from a machinery sound generating source whose position is fixed, and which a quantity of reflected wave is less.
In order to achieve an aspect of the present invention, a machinery sound absorbing apparatus includes a machine which generates a machinery sound, and a sound absorbing unit provided above the machine to have a convex shape in an upward direction. The sound absorbing unit includes a reflection plane as an underside surface opposing to the machine. The reflection plane is formed of a sound absorbing material and is a set of plane elements, each of which has an angle of 30 degree or less with respect of a vertical direction. Also, the reflection plane is smooth to a wavelength of the machinery sound.
Here, the sound absorbing material may be porous.
Also, the reflection plane may include two reflection flat planes which intersect to each other. Instead, the reflection plane may be a cone plane. Otherwise, the reflection plane may be a curved plane, and a partial element of the curved plane is the plane element. In this case, the sound absorbing material may be porous, or is formed of glass fiber or sponge.
In order to achieve another aspect of the present invention, a machinery sound absorbing apparatus includes a machine which generates a machinery sound, and a sound absorbing unit provided above the machine to have a reflection plane as an underside surface opposing to the machine. The machinery sound is reflected at least once by the reflection plane and returns to the machine.
Here, the reflection plane may be formed of a sound absorbing material. Also, the reflection plane may be a set of plane elements, each of which has an angle of 30 degree or less with respect of a vertical direction. Also, the reflection plane may be smooth to a wavelength of the machinery sound.
REFERENCES:
patent: 1584485 (1926-05-01), Stille
patent: 2721028 (1955-10-01), Dills
patent: 4095668 (1978-06-01), Derka
patent: 4503931 (1985-03-01), Sugimoto et al.
patent: 4558850 (1985-12-01), Melfi
patent: 4840251 (1989-06-01), Murase et al.
patent: 4883144 (1989-11-01), Haushalter et al.
patent: 57-172499 (1981-04-01), None
patent: 57-127321 (1982-08-01), None
patent: 59-186308 (1984-12-01), None
patent: 63-71211 (1988-05-01), None
patent: 9-212175 (1997-08-01), None
patent: 10-9999 (1998-01-01), None
Hutchins, Wheeler & Dittmar
Lockett Kim
Nappi Robert E.
NEC Corporation
LandOfFree
Apparatus for absorbing machinery sound does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus for absorbing machinery sound, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus for absorbing machinery sound will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2463319