Title: Non-uniform rigidity interface panel for a fluid-filled seat bladder
Abstract: A seat bladder weight estimation apparatus includes an interface panel having multiple regions of substantial rigidity separated by regions of insubstantial rigidity. The regions of substantial rigidity limit sensitivity to seat foam variations, and the regions of insubstantial rigidity permit differential movement and angulation of the rigid regions for regional transfer of occupant weight to the bladder. The regional transfer of occupant weight to the bladder allows regional variation of the bladder sensitivity to occupant weight through various bladder geometry design features.
Patent Number: 6,886,417 Issued on 05/03/2005 to Murphy, et al.
| Inventors:
|
Murphy; Morgan D. (Kokomo, IN);
Ginter; Mark A. (Russiaville, IN);
Waidner; John T (Carmel, IN)
|
| Assignee:
|
Delphi Technologies, Inc. (Troy, MI)
|
| Appl. No.:
|
665095 |
| Filed:
|
September 17, 2003 |
| Current U.S. Class: |
73/862.581 |
| Intern'l Class: |
G01L 007//00 |
| Field of Search: |
73/826,862.581,862.391,862.474
180/273
280/735,730.2
5/653
297/284.6
177/144
|
References Cited [Referenced By]
U.S. Patent Documents
Primary Examiner: Lefkowitz; Edward
Assistant Examiner: Davis; Octavia
Attorney, Agent or Firm: Chmielewski; Stefan V.
Claims
1. Occupant weight estimation apparatus for a vehicle seat comprising:
a fluid-filled elastomeric bladder disposed in said seat; and
an interface panel of non-uniform rigidity disposed adjacent to said elastomeric
bladder for transferring occupant weight to said bladder, said interface panel
having multiple rigid regions joined by intervening flexible regions, where said
intervening flexible regions deflect in response to occupant weight to permit differential
movement and angulation of said rigid regions to achieve regional transfer of said
occupant weight to said bladder.
2. Occupant weight estimation apparatus according to claim 1, where the interface
panel comprises:
a flexible base sheet; and
multiple rigid plates affixed to said base sheet.
3. Occupant weight estimation apparatus according to claim 2, wherein said base
sheet is a fabric material.
4. Occupant weight estimation apparatus according to claim 2, wherein said multiple
rigid plates exhibit different degrees of rigidity.
5. Occupant weight estimation apparatus according to claim 4, wherein said multiple
plates have different thicknesses.
6. Occupant weight estimation apparatus according to claim 1, where the interface
panel comprises:
a unitary sheet of non-uniform thickness.
7. Occupant weight estimation apparatus according to claim 1, where the interface
panel comprises:
multiple rigid plates affixed to a surface of said seat that engages said fluid-filled bladder.
8. Occupant weight estimation apparatus according to claim 7, wherein said multiple
rigid plates are affixed to a foam cushion of said seat by insert molding.
Description
TECHNICAL FIELD
The present invention is directed to a fluid-filled seat bladder for vehicle
occupant weight estimation, and more particularly to an interface panel for a bladder assembly.
BACKGROUND OF THE INVENTION
Vehicle occupant detection systems are useful in connection with air bags
and other pyrotechnically deployed restraints as a means of judging whether, and
how forcefully, to deploy the restraint. For example, it is useful to know the
seated weight of the occupant, and whether the detected weight is due to a normally
seated child or adult, or a cinched booster seat or infant carrier. Additionally,
the detection system must be capable of accurately providing the required occupant
information throughout the expected life of the vehicle.
A popular and cost-effective way of providing the above-mentioned occupant data
is to install a fluid-filled elastomeric bladder in or under the seat cushion,
and to measure the fluid pressure in the bladder. See for example, the U.S. Pat.
Nos. 5,987,370; 6,101,436; 6,246,936 and 6,490,936, assigned to the assignee of
the present invention, and incorporated herein by reference. The measured pressure
provides an indication of occupant weight, and the sensitivity of the bladder to
occupant weight in different areas of the seat can be tailored to effectively distinguish
between different types of occupants. For example, the bladder sensitivity can
be minimized in areas of the seat normally engaged by an infant or booster seat
so that the measured pressure for an infant or booster seat will be less than,
say, a 5
th percentile adult female occupant. In other words, the bladder
geometry can be designed to result in a weight separation between occupants for
whom deployment should be enabled and occupants for whom deployment should be disabled
or reduced in force. See, for example, the aforementioned U.S. Pat. No. 6,101,436,
where bladder sensitivity is tailored by selectively welding the top and bottom
layers of the bladder to form a pattern or array of flow-through cells or fluid-free
pockets. However, the use of bladder geometry features for sensitivity tuning can
be significantly restricted when a rigid interface panel or board is installed
between the bladder and seat cushion. Interface panels are used to provide a controlled
interface between the seat cushion and the bladder that limits the system sensitivity
to seat foam variations caused by manufacturing irregularities, temperature and
aging, and protects the bladder from puncture due to sharp objects coming into
contact with the cushion. Interface panels can also be used between the bladder
and the seat frame for similar reasons. See, for example, the aforementioned U.S.
Pat. No. 6,490,936. In any event, such interface panels tend to evenly distribute
the occupant weight over the bladder, masking the sensitivity variations that would
otherwise occur due to bladder geometry features. Accordingly, what is needed is
an interface panel for a seat bladder occupant weight estimation system that will
protect the bladder and limit the system sensitivity to seat foam and suspension
variations, without preventing the use of bladder geometry features for sensitivity control.
SUMMARY OF THE INVENTION
The present invention is directed to an improved seat bladder weight estimation
apparatus including an interface panel having multiple regions of substantial rigidity
separated by regions of insubstantial rigidity. The regions of substantial rigidity
limit sensitivity to seat foam variations, and the regions of insubstantial rigidity
permit differential movement and angulation of the rigid regions for regional transfer
of occupant weight to the bladder. The regional transfer of occupant weight to
the bladder allows regional variation of the bladder sensitivity to occupant weight
through various bladder geometry design features. The interface panel may be comprised
of rigid plates affixed to a flexible base sheet, or a single sheet of non-uniform
thickness. Additionally, the interface panel may be produced as a separate item
or integrated into the seat foam by insert molding.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will now be described, by way of example, with reference
to the accompanying drawings, in which:—
FIG. 1 is a system diagram including a fluid-filled seat bladder and upper and
lower interface panels according to this invention.
FIG. 2 is an isometric view of the upper interface panel of FIG. 1 according
to a first embodiment of this invention.
FIG. 3 is a cross-sectional view of the upper interface panel of FIG. 1 according
to a second embodiment of this invention.
FIG. 4 is a cross-sectional view of the upper interface panel of FIG. 1 according
to a third embodiment of this invention.
FIG. 5 is a cross-sectional view of the seat cushion and upper interface panel
of FIG. 1 according to a fourth embodiment of this invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the drawings, and particularly to FIG. 1, the reference numeral
10 generally designates a vehicle occupant weight estimation apparatus according
to this invention. The vehicle seat, generally designated by the reference numeral
12, includes a rigid frame and spring suspension
14, a bottom foam
cushion
16 and a back foam cushion
18. A set of posts
19 integral
to the frame
14 attach the seat
12 to pair of tracks
20 (only
one of which is shown in FIG. 1), which in turn, are secured to the vehicle floor
22. A bladder assembly
24 is sandwiched between the bottom cushion
16 and the suspension elements of frame
14 for the purpose of detecting
the presence and weight of an occupant of seat
12, as explained below. Finally,
a fabric cover
26 envelopes the cushion
16, bladder assembly
24
and frame
14.
The bladder assembly
24 comprises a fluid-filled elastomeric bladder
30,
upper and lower interface panels
32 and
34, and a pressure sensor
40. The bladder
30 is formed of upper and lower sheets
30a,
30b that are peripherally welded as indicated by the reference numeral
36 to form a closed volume, and selectively welded within the peripheral
weld
36 as indicated by the reference numerals
38 to form a plurality
of flow-through cells. In general, the weight of a vehicle occupant seated on the
cushion
16 is applied to the bladder
30, and an electronic controller
42 coupled to the pressure sensor
40 develops an estimation of the
occupant weight based on the measured pressure and its variation with respect to
time; see, for example, the aforementioned U.S. Pat. Nos. 5,987,370 and 6,246,936.
Additionally, the cells formed by the inter-peripheral welds
38 (and fluid-free
cells, if any) can be sized and positioned to tailor the bladder sensitivity to
the occupant weight, as described for example in the aforementioned U.S. Pat. No.
6,101,436. In addition to protecting bladder
30 from puncture damage, the
upper and lower interface panels
32 and
34 serve to limit the system
sensitivity to variations caused by manufacturing irregularities, temperature and
aging; the upper interface panel
32 limits the system sensitivity to seat
foam variations, while the lower interface panel
34 limits the system sensitivity
to seat frame/suspension variations.
According to the present invention, the interface panels
32,
34
exhibit a variable or non-uniform rigidity so as to achieve the usual interface
panel functionality without preventing the tailoring of bladder sensitivity through
variation of the bladder geometry. In general, the more rigid regions of the interface
panel
32,
34 limit system sensitivity to seat foam or suspension
variations, and the less rigid regions of the interface panel
32,
34
permit differential movement and angulation of the more rigid regions for regional
transfer of occupant weight to the bladder
30. The regional transfer of
occupant weight to the bladder
30 allows regional variation of the bladder
sensitivity to occupant weight through various bladder geometry design features
such as flow-through or fluid-free cells.
The interface panel non-uniformity can be achieved in several different ways,
four of which are depicted in FIGS. 2–5. The depicted embodiments are not
intended to be exhaustive in nature, and various other embodiments will occur to
those skilled in the art.
FIGS. 2 and 3 depict embodiments in which rigid plates
52,
54,
56;
62,
64,
66 are affixed to a flexible base sheet
50;
60. The base sheet
50,
60 merely serves as a carrier
for the plates
52,
54,
56;
62,
64,
66;
it exhibits insubstantial rigidity and may be a fabric material (such as Kevlar)
or a very thin plastic material. The plates
52,
54,
56;
62,
64,
66 may be formed of plastic, and are sewn, glued or otherwise
affixed to the base sheet
50,
60. The plates
52,
54,
56;
62,
64,
66 provide a controlled interface between
the bladder
30 and the seat foam
16 or suspension
14 that
limits system sensitivity to seat foam or suspension variations and protects the
bladder
30 from puncture damage. The base sheet
50,
60 permits
semi-independent movement and angulation of the plates
52,
54,
56;
62,
64,
66 for regional transfer of occupant weight to the
bladder
30 so that different areas of the bladder
30 are independently
activated by the occupant weight. In other words, the occupant weight is only regionally
distributed, and the regional sensitivity to occupant weight can be tailored through
the use of bladder geometry design features such as flow-through or fluid-free
cells. In the embodiment of FIG. 2, the plates
52,
54,
56
have similar thickness, and therefore similar rigidity. In the embodiment of FIG.
3, the plates
62,
64,
66 have different thickness to provide
different degrees of rigidity, as rigidity typically changes according to the cube
of thickness. More rigid sections of the interface panel
32,
34 provide
increased distribution of occupant weight over their area, and can be used to limit
system sensitivity to known seat foam or suspension irregularities. Alternatively,
different degrees of rigidity can be achieved by using plates
62,
64,
66 formed of different materials. In any event, the number and shape of
the plates
52,
54,
56;
62,
64,
66 depicted
in FIGS. 2 and 3 are merely exemplary, and may be customized for any given application.
FIG. 4 depicts an embodiment in which the interface panel
32,
34
is formed as a unitary sheet of non-uniform thickness, by injection molding for
example. The rigidity of the interface panel
32,
34 at any point
is a function of its thickness as mentioned above. The relatively thick sections
72,
74,
76 serve the function of the plates
52,
54,
56;
62,
64,
66 of FIGS. 2–3, and the thin sections
70 serve the function of the base sheet
50,
60 of FIGS. 2–3.
As with the embodiments of FIGS. 2–3, the number and shape of the relatively
thick sections
72,
74,
76 are merely exemplary, and may be
customized for any given application.
FIG. 5 depicts an embodiment of the upper interface panel
32 in which
rigid plates
82,
84,
86 are integrated into the seat cushion
foam
16 by insert-molding. In this case, the seat foam
16 serves
as the carrier for the plates
82,
84,
86, reducing the number
of parts in the bladder assembly
24. As with the embodiments of FIGS. 2–3,
the number and shape of the plates
82,
84,
86 are merely exemplary,
and may be customized for any given application.
In summary, the present invention provides an improved interface panel
32,
34 for installation between a fluid-filled seat bladder
30 and the
seat foam and/or suspension. The interface panels
32,
34 exhibit
a variable or non-uniform rigidity that protects the bladder and limits system
sensitivity to seat foam or suspension irregularities, while permitting regional
transfer of occupant weight to the bladder
30 so that the bladder sensitivity
to regionally applied occupant weight can be tailored through variation of the
bladder geometry. While the invention has been described in reference to the illustrated
embodiments, it should be understood that various modifications in addition to
those mentioned above will occur to persons skilled in the art, and that any of
a number of devices may fall within the scope of this invention, which is defined
by the appended claims.
*
