Note: Descriptions are shown in the official language in which they were submitted.
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SOUND INSULATING LAYER WITH INTEGRAL RIB STRUCTURE
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
This invention relates to a sound insulating layer for a vehicle,
and more particularly to a dash mat having an integrally formed dead pedal
and/or integrally molded compression ribs in the podalic areas of the vehicle.
DESCRIPTION OF THE RELATED ART
In most contemporary automobiles, a steel fire wall separates the
engine compartment from the passenger compartment. To reduce the
transmission of sound from the engine compartment through the fire wall and
into the passenger compartment, a sound barrier mat (otherwise known as a '
Is dash mat) is typicaliy molded as a single piece of an elastomeric material
of
substantially uniform thickness with limited impact absorption qualities. The
dash mat is mounted to and substantially overlies the fire wall such that an
outer surface of the mat is in contact with a bottom surface of the vehicle
carpet
and extends beyond the carpet to an upper portion of the fire wall behind the
2o instrument panel. A vehicle dead pedal, which serves as a foot rest for a
driver,
is typically formed of steel or plastic~and is subsequently installed with
fasteners on the wheel well of a vehicle. An opening or protrusion in the dash
mat is then aligned over the dead pedal and the dash mat is attached with
separate fasteners to the fire wall. Installation of the dead pedal and dash
mat
2s in this manner requires a plurality of different parts and fasteners. The
plurality
of parts and fasteners results in Increased inventory, expense, and
installation
time.
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SUMMARY C1F THE INVENTIOI~T
These and other problems of the prior art are overcome by an acoustical
barrier for a vehicle having an integrally formed rib structure in the podalic
area of the
vehicle.
According to the invention, an acoustical barrier adapted to be mounted to a
barrier wall, such as the wall of a vehicle or other structure, comprises a
mass layer of a
molded construction and sound dampening characteristics with an inner surface
that is
adapted to face the barrier wall and an outer surface adapted to face away
from the
barrier wall. A peripheral rib has an upper portion integrally formed with the
inner
surface of the mass layer and a lower portion with an outer edge that is
adapted to
contact the barrier wall. The peripheral rib defines an enclosed area on the
inner surface
of the mass layer. A first set of resilient projections are located within the
enclosed area.
Each projection has an upper portion integrally formed with the mass layer and
a lower
portion with an outer edge adapted to contact the barrier wall. Each
projection extends a
first distance from the inner surface to the outer edge. A second set of
resilient
projections are located within the enclosed area. Each projection of the
second set
includes an upper portion integrally formed with the mass layer and a lower
portion
with an outer edge adapted to face the barrier wall. Each projection of the
second set
extends a second distance from the inner surface to the outer edge.
Preferably, the
second distance is less than the first distance. With this arrangement, the
first set of
projections resiliently resists compressive forces applied to the outer
surface of the mass
layer at a first predetermined level and the second set of projections
together with the
first set of projections resiliently resist compressive forces at a second
predetermined
level greater than the first predetermined level.
The invention provides an acoustical barner adapted for installation in a
vehicle
having the barrier wall, the barner wall comprising a floor area and a fire
wall area
extending between a wheel well area and a drive train area, the fire wall area
intersecting
with and extending generally upwardly from the floor area, the acoustical
barrier
comprising:
a mass layer of a molded construction and sound dampening characteristics, the
mass
layer having an inner surface that is adapted to face the barrier wall and an
outer surface
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adapted to face away from the barrier wall;
a wheel well section shaped to conform to at least a portion of the shape of
the wheel
well area in the barrier wall;
floor and firewall sections shaped to conform to at least a portion of the
shape of the
floor and firewall areas, respectively, of the barrier wall;
characterized in a dead pedal integrally formed in the mass layer wheel
section and
projecting outwardly of the outer surface and inwardly of the inner surface of
the mass layer
to contact the wheel well area and to provide a dead pedal foot support, the
dead pedal
including a peripheral rib defining an enclosed area on the inner and outer
surfaces of the
mass layer and a first set of integral ribs that is within the enclosed area
and is integrally
formed with the peripheral rib.
The invention also provides an acoustical barrier adapted for installation in
a vehicle
having the barrier wall, the barner wall comprising a floor area and a fire
wall area extending
between a wheel well area and a drive train area , the fire wall area
intersecting with and
extending generally upwardly from the floor area, the acoustical barrier
comprising:
mass layer of a molded construction and sound dampening characteristics, the
mass
layer having an inner surface that is adapted to face the barrier wall and an
outer surface
adapted to face away from the barrier wall;
a wheel well section shaped to conform to at Least a portion of the shape of
the wheel
well area in the barrier wall;
floor and firewall sections shaped to conform to at least a portion of the
shape of the
floor and firewall areas, respectively, of the barrier wall; and
characterized in an enclosed area integrally formed in the mass layer floor
and firewall
sections at least in part by first and second sets of integral ribs, and the
enclosed area is
adapted to form a podalic zone extending along at least portions of the floor
and firewall
sections of the mass layer; and
an absorber layer having an outer surface in contact with the inner surface of
the mass
layer and an inner surface adapted to contact the barrier wall, wherein the
absorber layer has
an opening that is sized to receive the enclosed area formed in the mass layer
firewall sections
and the absorber layer lies wholly outside of the enclosed area.
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Further according to the invention, the mass layer is adapted for
installation in a vehicle having a barrier including a floor area and a fire
wall
area extending between a wheel well area and a drive train area. The fire wall
area intersects with and extends generally upwardly from the floor area. The
s mass layer also includes a wheel well section shaped to conform to at least
a
portion of the shape of the wheel well area, and floor and fire wall sections
shaped to conform to at least a portion of the shape of the floor and fire
wall
areas, respectively, of the vehicle.
In one embodiment, the enclosed area including the first and
1o second sets of projections comprises a podalic zone extending along at
least a
portion of the floor and firewall sections of tine mass layer.
in a further embodiment, a the enclosed area including the first
and second sets of projections comprises a dead pedal zone extending along at
least a portion of the wheel well section of the.mass layer.
is The acoustic barrier can also include an absorber layer having an
outer surface in contact with an inner surface of the mass layer and an inner
surface adapted to contact the barrier wall. preferably, the absorber layer
has
an opening that is sized to receive the peripheral rib such that the enclosed
area
is substantially free of the absorber material.
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Further according to the invention, an acoustical barrier adapted
to be mounted to a barrier wall comprises a mass layer of a molded
construction
and sound dampening characteristics with an inner surface that is adapted to
face the barrier wall and an outer surface adapted to face away from the
barrier
s wall. A peripheral rib has an upper portion integrally formed with the inner
surface of the mass layer and a lower portion with an outer edge adapted to
contact the barrier wall to thereby define an enclosed area on the inner
surface
of the mass layer. A first set of elongate ribs are located within the
enclosed
area. Each elongate rib includes an upper portion integrally formed with the
to inner surface of the mass layer and a lower portion with an outer edge
adapted
to at least face the barrier wall. Each elongate rib also has opposite ends
integrally formed with the peripheral rib to thereby strengthen the peripheral
rib
against bending moments due to compression forces applied to the outer
surface of the mass layer.
t s Preferably, the elongate ribs generally extend in the same
direction. A second set of elongate ribs located within the enclosed area can
be
provided. Each rib of the second set of ribs has an upper portion integrally
formed with the inner surface of the mass layer, a lower portion with an outer
edge adapted to at least face the barrier wall, and opposite ends integrally
2o formed with either adjacent ribs of the first set of ribs or the peripheral
rib and
an adjacent rib of the first set of ribs to thereby further strengthen the
peripheral
rib against bending moments.
BRIEF DESCRIPTIOl~1 OF THE DRAWINGS
T'he invention will now be described with reference to the
2s drawings in which:
FIG. 1 illustrates a front view (as viewed from the driver's seat)
of a dead pedal integrally formed with the vehicle dash mat;
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FIG. 2 is a rear view of the dead pedal and dash mat;
FIG. 3 is a top perspective view of the dash mat assembly
overlaying the fire wall showing the podalic area according to the invention;
FIG. 4 is a partial sectional view of the inner surface of the dash
mat with a sound absorber layer showing the compression rib structure of the
podalic area according to the invention; and
FIG. S is a cross-sectional view taken along line 5-5 of FIG. 4,
showing the variable height of the compression ribs.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
io Referring now to FIGS. 1-2, a dash mat assembly 10 includes a
mass layer or dash mat 12 having a first outer surface 14 and a second inner
surface 16. A dead pedal 18 is integrally formed in one piece with the mat 12
and protrudes outwardly from the first surface 14. The dash mat assembly 10 is
preferably formed of a filled elastomeric moldable polymer, e.g., elastomeric
1 s polypropylene, and serves as a sound barrier layer to reduce the
transmission of
sound from the engine compartment through the fire wall and into the
passenger compartment of a vehicle. A lower periphery 20 of the dead pedal
18 is continuous with the dash mat outer surface 14 and is shaped to conform
to
the surface of a vehicle wheel well (FIG. 3), such that an upper surface 22 of
20 the dead pedal 18 faces toward the rear of the vehicle and at a convenient
position for a user's foot when installed. A dead pedal peripheral wall 21 is
integrally formed with the Lower periphery 20 and the upper surface 22 of the
dead pedal 18.
A plurality of circular recesses 24 extend inwardly from the dead
2s pedal upper surface 22 for receiving a fastener (not shown). Each recess
includes an elongate slot 26 for receiving a fastener stud or shaft (not
shown)
that typically extends from the vehicle fire wall. The slots 26 are suff cient
so
that the dash mat 12 and dead pedal 18 can be adjusted with respect to the
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vehicle fire wall with the studs projecting through the slots during
installation.
Although only two recesses and slots are shown, it is to be understood that a
single recess and slot or a plurality of such can be provided depending on the
amount of securement needed. In addition, the recesses andlor slots can be
eliminated and the dead pedal can be free floating, depending on the type of
vehicle in which the dash mat is installed. The recesses and/or slots can also
be
used for the installation of a decorative cover.
With particular reference to FIG. 2, a first set of generally
longitudinally extending ribs 30 and a second set of generally laterally
extending ribs 32 project from an inner surface 28 of the dead pedal 18. The
first and second sets of ribs 30, 32 extend approximately perpendicular to
each
other and provide structural support to the dead pedal 18 to resist forces
applied
by a driver's foot. The first and second sets of ribs 30, 32 also give the
dead
pedal sufficient strength to mount a cover (not shown) directly to the dead
~s pedal through fasteners. ~uter edges 34 of the ribs 30 are adapted to abut
the
wheel well of a vehicle and, with the peripheral wall 21, thus support the
dead
pedal 18 thereagainst. ~uter edges 36 of the ribs 32 are curved toward the
inner surface 28 and generally do not contact the wheel well.
In the installed position, the inner surface 16 of the dash mat 12
2o and the outer edges 34 of the ribs 30 face the vehicle fire wall 25 (FIG.
3),
while the outer surfaces 14, 22 face the underside of a vehicle carpet (not
shown). The outer surface 14 of the dash mat 12 may also extend past the
carpet behind the instrument panel.
Although the invention finds particular use in automobile dash
25 mats, it is to be understood that the invention also finds use in other
automotive
or non-automotive applications wherein a panel or layer of material having an
integrally formed support surface is to be attached temporarily or permanently
to a support surface. For example, the dead pedal structure, i.e. the
reinforcing
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ribs, increased mat thickness, andlor fastener openings, can be formed at
other
locations in the dash mat to provide structural support for mounting
electrical
modules, HVAC cases, decorative panels, and other vehicle accessories.
Moreover, although the dead pedal has been illustrated with a particular
shape,
it is to be understood that other shapes can be formed in the dash mat
depending on the intended application.
Referring now to FIGS. 3 and 4, a barrier wall includes a drive
train area 42, a wheel well area 41, and floor and fire wall areas 23, 25
extending between the drive train area and the wheel well area. The fire wall
t o area 25 intersects with and extends generally upwardly from the floor area
23.
The dash mat assembly 10 may, in addition to or alternatively of the dead
pedal
18, include a compression rib matrix 3 8 integrally formed with the dash rnat
12
inner surface I6 at a podalic zone or area 40. The podalic zone 40 is located
at
the intersection of the floor 23 and the fire wall area 25 between the wheel
well
1s area 41 and the drive train area 42. The podalic zone 40 is substantially
divided
into a lower podalic portion 44 and an upper podalic portion 46. The lower
podalic portion 44 extends partially along the vehicle floor 23 adjacent the
fire
wall 25 and is integrally formed with the upper portion 46 which extends
partially upwards along the fire wall 25 adjacent the floor 23.
2o With particular reference to JFIG. 4, which is a rear view in partial
cross section of the podalic zone 40, the compression rib matrix 38 includes
generally longitudinally extending ribs 48 and generally laterally extending
ribs
50 that project from an inner dash mat surface 16 of the podalic area 40. The
ribs 48 extend approximately perpendicular to the ribs 50 with the ribs 48
2s having outer edges 54 and the ribs 50 having outer edges 60. A peripheral
rib
52 forms the outer perimeter of the compression rib matrix 38. A central rib
58
is formed integral with the peripheral rib 52 and is located at the
intersection of
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the upper and lower podalic portions 44, 46. Both the peripheral rib 52 and
central rib 58 have outer edges 62 and 64, respectively.
In the installed position, the outer edges 54 and 62 normally
contact the fire wall 25 and the floor 23; the outer edges 60 and the inner
surface 16 initially face the fire wall and floor; and the outer edge 58
extends
along and contacts the intersection of the fire wall and floor.
The acoustic barrier 10 can also include an absorber layer 56 that
is arranged between the inner surface 16 of the dash mat 12 and the fire wall
25
and/or floor 23 outside of the podalic area 40. The outer surface 14 of the
dash
m mat 12 faces the underside of a vehicle carpet (not shown) and is
substantially
uniform across the podalic area 40.
FIG. 5 is a cross-sectional view taken along line 5-5 of FIG. 4,
showing an exemplary arrangement of the compression ribs. The ribs 48, 50,
52 and 58 project from the inner surface 16 of the podalic area 40 at variable
is lengths to conform to the shape of the floor 23 and fire wall 25 and to
provide
structural support of variable resistance when a force is applied to the
podalic
area 40. As illustrated, a first set of ribs, Comprising ribs 48, peripheral
rib 52
and central rib 58, projects a first distance from the inner surface 16 such
that
the ribs 48, 58 and 52 space the inner surface 16 of the dash mat a
zo predetermined distance from the fire wall 25 and the floor 23. A second set
of
ribs, comprising the ribs 50, projects a second distance from the inner
surface
16. Preferably, the first distance is greater than the second distance, such
that
the outer surfaces 60 of the ribs 50 are initially spaced away from the wall
25
and floor 23. An impact of sufficient force applied to the outer surface of
the
zs podalic area 40 toward the floor 23 and/or fire wall 25 causes one or more
of
the ribs 48, 52 and 58 to flex and thereby initially dampen the impact force.
The initial level of dampening or impact resistance can be controlled by
varying
the number of ribs 48 and varying the thickness, height, length, spacing,
shape,
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and orientation of the ribs 48, 52 and 58 to achieve the desired amount of
initial
impact resistance. If the impact force is large enough to exceed the initial
impact resistance from the first set of ribs, one or more of the ribs from the
first
set continues to flex until one or mare of the outer surfaces 60 of the ribs
50
s contact the floor 23 and/or fire wall 25 to provide a second level of
dampening
or impact resistance. As with the first set of ribs, the second level of
dampening or impact resistance for the second set of ribs can be controlled by
varying the number of ribs 48 and varying the thickness, height, length,
spacing, shape, and orientation of the ribs to achieve the desired amount of
t o secondary impact resistance. The degree of impact resistance can
additionally
be controlled by surrounding the podalic zone 40 with an absorber layer 56 of
desired stiffness. The integrally molded compression rib matrix 38 provides
different levels of stiffness to the podalic zone 40 greater than a foam
absorber
layer alone and improves crash impact absorption and passenger safety. If
is desired, more than two degrees of impact resistance can be provided by the
addition of increasingly shorter sets of ribs.
Although the invention finds particular use m the podalic zone
40, it is to be understood that the compression ribs can be integrally formed
at
other locations in the dash mat to provide increased impact resistance, such
as
2o at the dead pedal zone located on the wheel well of a vehicle. Furthermore,
the
invention is not limited to the particular arrangement of ribs as referenced
in the
drawings.
Reasonable variation and modification are therefore possible
within the spirit of the foregoing specification and drawings without
departing
2s from the scope of the invention.
