U.S. patent application number 10/976617 was filed with the patent office on 2006-05-04 for fluid/foam filled seat bladder for occupant weight estimation.
Invention is credited to Duane D. Fortune, Mark A. Koors, John T. Waidner.
Application Number | 20060091716 10/976617 |
Document ID | / |
Family ID | 36260982 |
Filed Date | 2006-05-04 |
United States Patent
Application |
20060091716 |
Kind Code |
A1 |
Fortune; Duane D. ; et
al. |
May 4, 2006 |
Fluid/foam filled seat bladder for occupant weight estimation
Abstract
A seat bladder has a closed volume that is at least partially
filled with an open-cell or highly-reticulated foam material. The
bladder fluid soaks into interstices in the foam material and fills
the remaining bladder volume. The presence of the foam material
reduces the time required to evacuate the bladder prior to fluid
filling, and reduces the quantity of fluid required to fill the
bladder. In subsequent usage, the foam material increases the
restoring force of the bladder and the dissipation of energy input
to the bladder.
Inventors: |
Fortune; Duane D.; (Lebanon,
IN) ; Waidner; John T.; (Carmel, IN) ; Koors;
Mark A.; (Kokomo, IN) |
Correspondence
Address: |
DELPHI TECHNOLOGIES, INC.
M/C 480-410-202
PO BOX 5052
TROY
MI
48007
US
|
Family ID: |
36260982 |
Appl. No.: |
10/976617 |
Filed: |
October 29, 2004 |
Current U.S.
Class: |
297/452.41 |
Current CPC
Class: |
A47C 31/126 20130101;
B60N 2/914 20180201; A47C 4/54 20130101; A47C 27/18 20130101 |
Class at
Publication: |
297/452.41 |
International
Class: |
A47C 7/02 20060101
A47C007/02 |
Claims
1. A seat bladder for estimating the weight of a seat occupant,
comprising: upper and lower sheets of elastomeric material joined
by a peripheral seam to define a closed volume; a sheet of foam
material disposed between said upper and lower sheets of
elastomeric material within said peripheral seam, said foam
material defining a network of interconnected cells; and a fluid
disposed within said closed volume and substantially filling said
network of interconnected cells.
2. (canceled)
3. The seat bladder of claim 1, further comprising: at least one
weld joining said upper and lower sheets of elastomeric material
within said peripheral seam, said sheet of open cell foam material
having an opening aligned with said weld so that said open cell
foam material is not included in said weld.
4. The seat bladder of claim 1, further comprising: at least one
weld joining said upper and lower sheets of elastomeric material
within said peripheral seam, where said weld includes a region of
open cell foam material intermediate the joined upper and lower
sheets of elastomeric material.
5. The seat bladder of claim 4, wherein said elastomeric material
and said open cell foam material both comprise polyurethane.
6. The seat bladder of claim 1, wherein said open cell foam
material has a porosity in the range of about five pores per inch
to about twenty pores per inch.
7. The seat bladder of claim 1, wherein said fluid comprises
silicone.
Description
TECHNICAL FIELD
[0001] The present invention relates to estimating the seated
weight of a seat occupant with a fluid-filled elastomeric bladder
installed in the seat, and more particularly to a bladder that is
at least partially filled with an open-cell foam material.
BACKGROUND OF THE INVENTION
[0002] It has been demonstrated that the weight of a vehicle seat
occupant can be effectively measured for purposes of determining
whether to allow or suppress deployment of supplemental inflatable
restraints by measuring the pressure in a fluid-filled seat
bladder. See, for example, the U.S. Pat. Nos. 5,987,370 and
6,246,936, incorporated by reference herein. Silicone is a suitable
bladder fluid, because it is non-corrosive and not subject to
freezing even under extreme ambient conditions. As described in the
U.S. Pat. No. 6,101,436, also incorporated by reference herein, the
upper and lower surfaces of the seat bladder can be joined by a
pattern of spot welds in order to prevent pooling and to reduce the
amount of fluid required to fill the bladder.
SUMMARY OF THE INVENTION
[0003] The present invention is directed to an improved seat
bladder in which the closed volume of the bladder is at least
partially filled with an open-cell or highly-reticulated foam
material at the time of bladder manufacture. When fluid is
subsequently added to the bladder, it soaks into interstices in the
foam material and fills the remaining bladder volume. In
manufacture, the presence of the foam material reduces the time
required to evacuate the bladder prior to fluid filling, and
reduces the quantity of fluid required to fill the bladder. In
usage, the foam material increases the restoring force of the
bladder and the dissipation of energy input to the bladder.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1 is an illustration of a prior art fluid-filled seat
bladder installed in a vehicle seat;
[0005] FIGS. 2A and 2B depict the formation of a fluid-filled seat
bladder according to a first embodiment of the present invention;
and
[0006] FIGS. 3A and 3B depict the formation of a fluid-filled seat
bladder according to a second embodiment of the present
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0007] Referring to the drawings, and particularly to FIG. 1, the
reference numeral 10 generally designates a vehicle seat equipped
with a prior art occupant weight estimation apparatus including a
fluid-filled seat bladder 12. The seat 10 includes a frame and
cushion pad 14, a bottom foam cushion 16 and a back foam cushion
18. A set of fasteners 19 attach the seat 10 to a pair of tracks 20
that are secured to risers, which in turn, are secured to the
vehicle floor 22. A bladder assembly 24 is sandwiched between the
bottom cushion 16 and the frame and cushion pad 14, and a fabric
cover 26 envelops the cushion 16, bladder assembly 24 and the frame
and cushion pad 14.
[0008] In the embodiment of FIG. 1, the bladder assembly 24
comprises the fluid-filled bladder 12, upper and lower interface
panels 32 and 34, and a pressure sensor 40. The bladder 12 is
formed of upper and lower sheets 12a, 12b of elastomeric material
that are peripherally welded as indicated by the reference numeral
36 to form a closed volume, and selectively spot welded within the
peripheral weld 36 as indicated by the reference numerals 38 to
form a plurality of flow-through cells. The bladder 12 is filled
with a fluid such as silicone that is non-corrosive and less
subject to freezing under any naturally occurring ambient
temperature conditions. In general, the weight of an occupant
seated on the cushion 16 is applied to the bladder 12, and an
electronic controller 42 coupled to the pressure sensor 40 develops
a response to the occupant weight pressure on the bladder 12 and/or
its variation with respect to time; see, for example, the
aforementioned U.S. Pat. Nos. 5,987,370 and 6,246,936. As noted in
the aforementioned U.S. Pat. No. 6,101,436, the inter-peripheral
welds 38 can prevent pooling of fluid within bladder 12 and also
reduce the amount of fluid required to fill the bladder 12.
[0009] The present invention is directed to an improved seat
bladder in which the closed volume of the bladder is at least
partially filled with an open-cell or highly-reticulated foam
material at the time of bladder manufacture. When fluid is
subsequently added to the bladder, it soaks into interstices in the
foam material and fills the remaining bladder volume. The open cell
foam reduces the volume of air in the sealed bladder; this reduces
the time required to evacuate the bladder prior to fluid filling,
and reduces the quantity of fluid required to subsequently fill the
bladder. Reducing the quantity of silicone in the bladder is
significant for at least two reasons: (1) it reduces the weight of
the bladder, and (2) it reduces the cost of the bladder.
Furthermore, the open cell foam material retains its springiness
after manufacture; this increases the dissipation of energy when a
load is applied to the bladder, and increases the restoring force
of the bladder when the load is subsequently removed.
[0010] FIGS. 2A-2B and FIGS. 3A-3B respectively depict the
formation of an open cell foam containing seat bladder 50, 60
according to first and second embodiments of this invention. In
each case, a sheet 52, 52' of open cell foam material similar in
shape to that of the intended bladder 50,60, but somewhat smaller
in area, is positioned between two sheets 54, 56 of elastomeric
material that will become the upper and lower bladder sheets 12a,
12b. Preferably, both the open cell foam material 52, 52' and the
elastomeric sheets 54, 56 are made from polyurethane. A nominal
thickness of the elastomeric sheets 54, 56 is 0.36 mm, and a
nominal thickness of the open cell foam material 52, 52' is 5
mm.
[0011] Marginal portions of the elastomeric sheets 54, 56 are
joined together to form the peripheral seam or weld 36, sealing the
sheet 52, 52' of open cell foam material within the bladder 50, 60.
Thereafter, a the upper and lower sheets 54, 56 are joined in a
pattern of spot welds 38 within the peripheral weld 36, as
illustrated in FIG. 1. According to the first embodiment depicted
in FIGS. 2A-2B, the sheet 52 of open cell foam material is
continuous within the peripheral weld 36, and is included in the
spot welds 38. Such inclusion of the open cell foam material within
the spot welds 38, and optionally within the peripheral weld 36 as
well, is achieved most effectively when the elastomeric sheets 54,
56 and the open cell foam material 52 are both comprised of the
same substance such as polyurethane. According to the second
embodiment depicted in FIGS. 3A-3B, the sheet 52' of open cell foam
material is provided with openings 58 within its periphery that are
aligned with the intended locations of the spot welds 38; in this
case, none of the open cell foam material 52' is included in the
spot welds 38.
[0012] In summary, the present invention provides an improved seat
bladder that encloses an open cell foam material. The presence of
the foam material reduces the time required to evacuate the bladder
prior to fluid filling, and when the fluid is added, it soaks into
interstices in the foam material and fills the remaining bladder
volume. The open cell foam material may have a porosity in the
range about 5-20 pores per inch, and a porosity of 10 pores per
inch is considered to be optimal. The reduced quantity of fluid
within the bladder reduces the bladder weight, and makes the
bladder assembly 24 easier to install in a seat 10. Additionally,
the color of the foam material may be selected to permit easy and
reliable visual distinction between versions of the bladder. And in
subsequent usage, the foam material increases the restoring force
of the bladder and the dissipation of energy input to the bladder,
as mentioned above.
[0013] While the invention has been described with respect to the
illustrated embodiment, it is recognized that numerous
modifications and variations in addition to those mentioned herein
will occur to those skilled in the art. For example, even though
the use of period spot welds as illustrated herein is believed to
provide the best overall performance in an occupant weight
detection system, it may be desired to dispense with the spot welds
and to use the open cell foam material to minimize distension of
the bladder and consequent pooling of the bladder fluid. This can
be achieved, for example, by bonding the open cell foam material to
the upper and lower sheets of elastomeric material prior to the
peripheral welding operation. Accordingly, it is intended that the
invention not be limited to the disclosed embodiment, but that it
have the full scope permitted by the language of the following
claims.
* * * * *