U.S. patent number RE39,010 [Application Number 10/171,181] was granted by the patent office on 2006-03-14 for lightweight acoustical system.
This patent grant is currently assigned to Lear Corporation. Invention is credited to David Boyles, Gordon Ebbitt, Laura E. Gish, Liangyu Huang, Barry Wyerman.
United States Patent |
RE39,010 |
Gish , et al. |
March 14, 2006 |
Lightweight acoustical system
Abstract
An improved acoustical system for inhibiting noise in a motor
vehicle. The system comprises an impermeable layer and an
underlayment adjacent to the impermeable layer. The underlayment
includes a first fibrous layer and a second fibrous layer. The
underlayment has an airflow resistance between about 2000 and about
5000 mks Rayls.
Inventors: |
Gish; Laura E. (Carlisle,
PA), Huang; Liangyu (Novi, MI), Ebbitt; Gordon (Ann
Arbor, MI), Wyerman; Barry (Novi, MI), Boyles; David
(Carlisle, PA) |
Assignee: |
Lear Corporation (Southfield,
MI)
|
Family
ID: |
24346005 |
Appl.
No.: |
10/171,181 |
Filed: |
June 13, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
09586504 |
Jun 2, 2000 |
06296075 |
Oct 2, 2001 |
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Current U.S.
Class: |
181/290;
181/286 |
Current CPC
Class: |
B60R
13/083 (20130101); B60R 13/0892 (20130101); G10K
11/162 (20130101); G10K 11/168 (20130101); B32B
27/12 (20130101); B32B 27/32 (20130101); B32B
5/26 (20130101); B32B 2307/7265 (20130101); B32B
2471/02 (20130101); B32B 2307/10 (20130101); B32B
2323/04 (20130101) |
Current International
Class: |
E04B
1/82 (20060101) |
Field of
Search: |
;181/284,286,290,291,294,295 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0 229 977 |
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Dec 1986 |
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EP |
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0 229 977 |
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EP |
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0 229 977 |
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Jul 1987 |
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EP |
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0 732 684 |
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Sep 1996 |
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EP |
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0 934 180 |
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Oct 1997 |
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EP |
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2 100 620 |
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Jan 1983 |
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GB |
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2 163 388 |
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Feb 1986 |
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GB |
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2 319 998 |
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Jun 1998 |
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GB |
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62-48545 |
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Mar 1987 |
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JP |
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04009898 |
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Jan 1992 |
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JP |
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WO 98/18656 |
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May 1998 |
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WO |
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WO 98/18657 |
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May 1998 |
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WO |
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WO 99/44817 |
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Sep 1999 |
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WO |
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Primary Examiner: Dang; Khanh
Attorney, Agent or Firm: Brooks Kushman P.C.
Claims
What is claimed is:
1. An acoustical system comprising: a water-impermeable layer; an
underlayment adjacent to the impermeable layer, the underlayment
including a first fibrous layer and a second fibrous layer, the
first fibrous layer having a density less than a density of the
second fibrous layer; the underlayment having a specific airflow
resistance between about 2000 and about 5000 mks Rayls; and a
semi-permeable layer disposed between the first and second fibrous
layers.
2. The acoustical system of claim 1 wherein the semi-permeable
layer comprises a film.
3. The acoustical system of claim 1 wherein the first fibrous layer
has a surface density between about 500 grams per square meter and
about 1400 grams per square meter.
4. The acoustical system of claim 1 wherein the second fibrous
layer has a surface density between about 500 grams per square
meter and about 1400 grams per square meter.
5. The acoustical system of claim 1 wherein the second fibrous
layer is adjacent to the impermeable layer.
6. The acoustical system of claim 1 wherein the second fibrous
layer is a composite.
7. The acoustical system of claim 1 wherein the underlayment is
situated between the impermeable layer and a noise source.
8. The acoustical system of claim 1 further comprising a decorative
layer situated adjacent to the impermeable layer.
9. A carpet with noise-inhibiting characteristics for use in a
motor vehicle, the carpet comprising: a water-impermeable layer;
and an underlayment adjacent to the impermeable layer, the
underlayment including a first fibrous layer and a second fibrous
layer, the first fibrous layer having a density less than a density
of the second fibrous layer; the underlayment having a specific
airflow resistance between about 2000 and about 5000 mks Rayls;
wherein the first and second fibrous layers have a surface density
between about 500 grams per square meter and about 1400 grams per
square meter.
10. The carpet of claim 9 further comprising a semi-permeable layer
disposed between the first and second fibrous layers.
11. The carpet of claim 10 wherein the semi-permeable layer
comprises a film.
12. The carpet of claim 9 wherein the second fibrous layer is
adjacent to the impermeable layer.
13. The carpet of claim 9 wherein the second fibrous layer is a
composite.
14. The carpet of claim 9 wherein the underlayment is situated
between the impermeable layer and a noise source.
15. The carpet of claim 9 wherein the first layer is situated
between the second layer and a noise source.
16. A system for inhibiting noise in a motor vehicle, the system
comprising: an impermeable layer; and an underlayment adjacent to
the impermeable layer, the underlayment including a first fibrous
layer, a second fibrous layer, and a semi-permeable layer, the
first layer having a surface density between about 500 grams per
square meter and about 1400 .[.grains.]. .Iadd.grams .Iaddend.per
square meter, and the second layer having a surface density between
about 500 grams per square meter and about 1400 grams per square
meter; the underlayment having a specific airflow resistance
between about 2000 and about 5000 mks Rayls.
.Iadd.17. An acoustical system comprising: a water-impermeable
layer; an underlayment adjacent to the impermeable layer, the
underlayment including a first layer and a second layer, the first
layer having a density less than a density of the second layer, and
a semi-permeable layer disposed between the first and second
layers; and the underlayment having a specific airflow resistance
between about 2000 and about 5000 mks Rayls..Iaddend.
.Iadd.18. The acoustical system of claim 17 wherein the
semi-permeable layer comprises a film..Iaddend.
.Iadd.19. The acoustical system of claim 17 wherein the first layer
has a surface density between about 500 grams per square meter and
about 1400 grams per square meter..Iaddend.
.Iadd.20. The acoustical system of claim 17 wherein the second
layer has a surface density between about 500 grams per square
meter and about 1400 grams per square meter..Iaddend.
.Iadd.21. The acoustical system of claim 17 wherein the second
layer is adjacent to the impermeable layer..Iaddend.
.Iadd.22. The acoustical system of claim 17 wherein the second
layer is a composite..Iaddend.
.Iadd.23. The acoustical system of claim 17 wherein the
underlayment is situated between the impermeable layer and a noise
source..Iaddend.
.Iadd.24. The acoustical system of claim 17 further comprising a
decorative layer situated adjacent to the impermeable
layer..Iaddend.
.Iadd.25. A carpet with noise-inhibiting characteristics for use in
a motor vehicle, the carpet comprising: a water-impermeable layer;
and an underlayment adjacent to the impermeable layer, the
underlayment including a first layer and a second layer, the first
layer having a density less than a density of the second layer; the
underlayment having a specific air flow resistance between about
2000 and 5000 mks Rayls; wherein the first and second layers have a
surface density between about 500 grams per square meter and about
1400 grams per square meter..Iaddend.
.Iadd.26. The carpet of claim 25 further comprising a
semi-permeable layer disposed between the first and second
layers..Iaddend.
.Iadd.27. The carpet of claim 26 wherein the semi-permeable layer
comprises a film..Iaddend.
.Iadd.28. The carpet of claim 25 wherein the second layer is
adjacent to the impermeable layer..Iaddend.
.Iadd.29. The carpet of claim 25 wherein the second layer is a
composite..Iaddend.
.Iadd.30. The carpet of claim 25 wherein the underlayment is
situated between the impermeable layer and a noise
source..Iaddend.
.Iadd.31. The carpet of claim 25 wherein the first layer is
situated between the second layer and a noise source..Iaddend.
.Iadd.32. A system for inhibiting noise in a motor vehicle, the
system comprising: an impermeable layer; and an underlayment
adjacent to the impermeable layer, the underlayment including a
first layer, a second layer, and a semi-permeable layer, the first
layer having a surface density between about 500 grams per square
meter and about 1400 grams per square meter, and the second layer
having a surface density between about 500 grams per square meter
and about 1400 grams per square meter; the underlayment having a
specific airflow resistance between about 2000 and about 5000 mks
Rayls..Iaddend.
Description
TECHNICAL FIELD
This invention relates to acoustical systems.
BACKGROUND ART
The use of a permeable facing fabric or film on an acoustical
absorber to improve its low frequency response has been shown in
the literature and in numerous commercial applications, primarily
in the building and construction field. Recently this concept has
been applied to motor vehicle interior acoustical products. While
these arrangements may demonstrate improved sound transmission loss
in the mid-frequency range as compared to a double-walled system,
they also typically exhibit decreased sound transmission loss at
higher frequencies. Furthermore, a porous surface may cause several
practical problems. When used on the floor of a motor vehicle, an
acoustical absorber having a water-permeable facing is susceptible
to water intrusion which may cause formation of mildew and odor in
the underpad, as well as rust the floor pan in some cases.
DISCLOSURE OF INVENTION
This invention provides an improved acoustical system comprising a
water-impermeable layer and an underlayment. The underlayment is
adjacent to the impermeable layer, and includes a first fibrous
layer and a second fibrous layer. The first fibrous layer has a
density less than the density of the second fibrous layer, and the
underlayment has an airflow resistance between about 2000 and about
5000 mks Rayls.
Accordingly, it is an object of the present invention to provide an
improved acoustical system which functions sufficiently over a
broad frequency range. Another object of the present invention is
to provide an improved acoustical barrier which is not susceptible
to water intrusion.
These and other objects, features, and advantages of the present
invention are readily apparent from the following detailed
description of the best modes for carrying out the invention when
taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF DRAWING
FIG. 1 is a cross-sectional view of an acoustical system according
to the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
With reference to the drawing, the preferred embodiments of the
present invention will be described. FIG. 1 shows a system 10 for
inhibiting noise in a motor vehicle. The system 10 comprises a
water-impermeable, relatively lightweight layer 12 and an
underlayment 14.
The underlayment 14 is situated next to the impermeable layer 12,
and includes a first or lofty fibrous layer 16 and a second or
compressed fibrous layer 18. In a preferred embodiment, both of the
layers 16 and 18 contain recycled, non-woven fibers which have been
fluffed and combed to create a non-directional matrix or batt. Both
layers 16 and 18 preferably have a surface density between about
500 grams per square meter and about 1400 grams per square
meter.
A semi-permeable layer 20, comprising a fusible plastic film or
cellulose filter scrim with a heat-settable adhesive, is preferably
positioned between the layers 16 and 18 to provide additional
airflow resistance and to help bond the layers together. In the
case of a scrim, the material preferably has a surface density in
the range of about 44 grams per square meter. A decorative layer 22
such as carpet or a face fabric may also be provided adjacent to
the impermeable layer 12.
To make the acoustical system 10, approximately equal thicknesses
of the layers 16 and 18 are first preferably heat set through an
oven. One of the layers 16 or 18 is then bonded to the
semi-permeable layer 20, and the combination bonded to the other
layer 18 or 16. The resulting laminate is heated for about 30-40
seconds at about 400 to 450 degrees F, and then put into a cooled
mold. When the mold is closed, the layers 16 and 18 are
differentially compressed. The facing 22, which is first coated
with the impermeable layer 12 of a 200-500 grams per square meter
polyethylene to a thickness less than 1 mm, and more preferably
about 0.1 mm, is then bonded to the underlayment 14 by heating the
impermeable layer to near its melting point, and then transferring
it to a cool mold into which the underlayment has been placed.
In the final product, the underlayment 14 preferably has a total
thickness of 10-25 millimeters (mm), with the second or compressed
layer 18 accounting for about 3 mm of that thickness and a
resultingly higher as-molded density than the first or lofty layer
16. In this configuration, the underlayment has a specific airflow
resistance between about 2000 and about 5000 mks Rayls, and
preferably between about 2500 and 4500 mks Rayls. The system 10 can
be placed on the sheet metal 24 of the motor vehicle so that the
lofty layer 16 is next to the metal and the compressed layer 18 is
next to the impermeable layer 12.
The invention is an improvement over the prior art. It modifies the
construction for improved performance over a broad frequency range
and eliminates the physical deficiencies. The sound transmission
loss of this system is significantly improved over a typical heavy
barrier system in the mid-range frequencies of about 200 to 1000
Hz, and is roughly equivalent to a heavy barrier system at high
frequencies as well. These results were not expected based on
experience with previous lightweight systems. Other lightweight
systems all demonstrate a significant reduction in transmission
loss at higher frequencies. Furthermore, the system 10 is
preferably formed entirely from thermoplastics so as to be totally
recyclable.
This invention is particularly applicable to floor systems for
motor vehicles, but may have other vehicle or architectural noise
attenuation applications. In some of those applications, such as
dash insulators for motor vehicles, a carpet is not necessary. The
design of the impermeable layer allows the acoustical properties of
the construction to be tailored for transmission loss and/or sound
absorption over specific frequency regions.
While the embodiments of the invention shown and described above
constitute preferred embodiments of the invention, they are not
intended to illustrate all possible forms thereof. It should also
be understood that the words used are words of description rather
than limitation, and various changes may be made without departing
from the spirit and scope of the invention disclosed.
* * * * *