U.S. patent application number 11/016977 was filed with the patent office on 2005-06-30 for padding for the seat proper of a vehicle seat and a seat proper equipped with such padding.
Invention is credited to Kang, Ho-Sung, Richard, Olivier.
Application Number | 20050140199 11/016977 |
Document ID | / |
Family ID | 34639620 |
Filed Date | 2005-06-30 |
United States Patent
Application |
20050140199 |
Kind Code |
A1 |
Kang, Ho-Sung ; et
al. |
June 30, 2005 |
Padding for the seat proper of a vehicle seat and a seat proper
equipped with such padding
Abstract
Padding for the seat proper of a seat, the padding comprising a
visco-elastic foam and a comfort foam. The visco-elastic foam
extends between a bottom face of the seat proper and an
intermediate level of the padding. The comfort foam extends between
the intermediate level and the top face of the seat proper. The
comfort foam and the visco-elastic foam extend both over the rear
and over the front of the seat proper.
Inventors: |
Kang, Ho-Sung; (Antony,
FR) ; Richard, Olivier; (Etampes, FR) |
Correspondence
Address: |
MCCRACKEN & FRANK LLP
200 W. ADAMS STREET
SUITE 2150
CHICAGO
IL
60606
US
|
Family ID: |
34639620 |
Appl. No.: |
11/016977 |
Filed: |
December 20, 2004 |
Current U.S.
Class: |
297/452.27 |
Current CPC
Class: |
B60N 2/7035 20130101;
B60N 2/4263 20130101 |
Class at
Publication: |
297/452.27 |
International
Class: |
A47C 007/02 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 24, 2003 |
FR |
0315416 |
Claims
What is claimed is:
1. Padding for the seat proper of a vehicle seat, the padding
extending in a longitudinal direction between a rear portion
serving to receive the pelvis of an occupant sitting on the seat
and a front portion, and in a vertical direction, between a bottom
surface designed to face towards a vehicle floor, and a top surface
designed to face towards the body of the occupant, said padding
comprising at least: a comfort foam that is soft both when the seat
proper is in normal use, and when the vehicle decelerates suddenly;
and a visco-elastic foam that is stiffer when the vehicle
decelerates suddenly than when the vehicle is in normal use; said
visco-elastic foam extending from the bottom surface, and said
comfort foam, secured to said visco-elastic foam, extending to the
top surface of the padding; said comfort foam and said
visco-elastic foam extending from the rear portion to the front
portion of the padding, wherein said visco-elastic foam presents a
stiffening thickness that varies.
2. Padding according to claim 1, in which said rear portion
presents a rear end, and said front portion presents a front end;
in which said comfort foam presents a comfort thickness that varies
between said rear end and said front end; and in which a ratio
between the comfort thickness and the sum of the comfort thickness
and of the stiffening thickness varies in said longitudinal
direction.
3. Padding according to claim 2, in which said ratio decreases from
said rear end to said front end.
4. Padding according to claim 2, in which said rear portion extends
from said rear end towards the front end over a distance
corresponding substantially to one third of the distance between
the front end and the rear end, and in which, in the rear portion,
said ratio lies in the range 40% to 80%, and preferably in the
range 50% to 70%.
5. Padding according to claim 2, in which said front portion
extends from said front end towards the rear end over a distance
corresponding substantially to one third of the distance between
the front end and the rear end; and in which, in the front portion,
said comfort foam presents a comfort thickness smaller than 0.05 m,
and preferably smaller than 0.03 m.
6. Padding according to claim 1, in which said visco-elastic foam
presents a stiffening coefficient R greater than 10, the stiffening
coefficient R being defined as the ratio between dynamic lift and
quasi-static lift, lift being the ratio between the compression
force to be exerted on the surface of a portion of foam in order to
deform said portion by 50% and the area of said surface of the
portion, dynamic lift being obtained for a deformation rate of not
less than 10 s.sup.-1.
7. Padding according to claim 1, further comprising an intermediate
portion between said front portion and said rear portion, and a
rigid element which is mounted on the bottom surface of said
intermediate portion.
8. A seat proper having a rigid structure on which padding
according to claim 1 is mounted, said padding being covered with a
cover.
9. A seat proper structure having a rigid structure on which
padding according to claim 1 is mounted, said padding further
comprising an intermediate portion between said front portion and
said rear portion, and said rigid structure further comprising a
rigid element disposed facing said intermediate portion of said
padding.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to padding for the seat proper
of a vehicle seat.
[0002] More particularly, the invention relates to padding for the
seat proper of a vehicle seat, the padding extending in a
longitudinal direction between a front portion and a rear portion
serving to receive the pelvis of an occupant sitting on the seat,
and in a vertical direction, between a bottom surface designed to
face towards a vehicle floor, and a top surface designed to face
towards the body of the occupant, said padding comprising at
least:
[0003] a comfort foam that is soft both when the seat is in normal
use, and when the vehicle decelerates suddenly; and
[0004] a visco-elastic foam that is stiffer when the vehicle
decelerates suddenly than when the vehicle is in normal use;
[0005] said visco-elastic foam extending from the bottom surface,
and said comfort foam, secured to said visco-elastic foam,
extending to the top surface of the padding.
BACKGROUND OF THE INVENTION
[0006] Use of such visco-elastic foams is known, in particular from
Patent Application FR 2 795 371 which describes a seat proper or
another seat element in which the padding is made up in part of
visco-elastic foam. In the event of frontal impact, an occupant
sitting on a seat provided with such padding has the pelvis braked
progressively, thereby preventing "submarining", i.e. sliding under
the lap-belt, while also reducing compression of the lumbar region
of the occupant. Various mounting configurations for mounting
visco-elastic foams in the padding are described, such foam
extending, for example, in the front portion of the padding, or
even occupying the entire volume of the padding. In order for the
restraining effect procured by the visco-elastic foam to be fully
advantageous, it is also necessary for the occupant to be able to
enjoy normal use of the vehicle without being inconvenienced by the
presence of such a visco-elastic foam in the seat. The presence of
visco-elastic foam degrades the degree of comfort offered by the
seat. Thus, none of the embodiments presented in FR 2 795 371
really optimizes both the comfort of the occupant during normal use
of the vehicle and also the anti-submarining effect.
[0007] WO 00/36951 also describes such a type of padding, in which
the comfort and visco-elastic foams extend from the rear portion to
the front portion. However, the padding described in that document
similarly does not make it possible to optimize the comfort and the
anti-submarining effect, e.g. in a manner adapted to the
geometrical shape of the seat proper.
OBJECTS AND SUMMARY OF THE INVENTION
[0008] A particular object of the present invention is to mitigate
those drawbacks.
[0009] To this end, according to the invention, in padding of the
type in question, said visco-elastic foam presents a stiffening
thickness that varies between said rear end and said front end.
[0010] By means of these provisions, occupant safety is improved
relative to the safety procured with known padding, without the
improvement being achieved to the detriment of comfort.
[0011] In preferred embodiments of the invention, it is optionally
possible to use one or more of the following provisions:
[0012] said rear portion presents a rear end, and said front
portion presents a front end;
[0013] said comfort foam presents a comfort thickness that varies
between said rear end and said front end; and
[0014] a ratio between the comfort thickness and the sum of the
comfort thickness and of the stiffening thickness varies in said
longitudinal direction;
[0015] said ratio decreases from said rear end to said front
end;
[0016] said rear portion extends from said rear end towards the
front end over a distance corresponding substantially to one third
of the distance between the front end and the rear end, and, in the
rear portion, said ratio lies in the range 40% to 80%, and
preferably in the range 50% to 70%;
[0017] said front portion extends from said front end towards the
rear end over a distance corresponding substantially to one third
of the distance between the front end and the rear end; and
[0018] in the front portion, said comfort foam presents a comfort
thickness smaller than 0.05 meters (m), and preferably smaller than
0.03 .mu.m;
[0019] said visco-elastic foam presents a stiffening coefficient R
greater than 10, the stiffening coefficient R being defined as the
ratio between dynamic lift and quasi-static lift, lift being the
ratio between the compression force to be exerted on the surface of
a portion of foam in order to deform said portion by 50% and the
area of said surface of the portion, dynamic lift being obtained
for a deformation rate of not less than 10 per second (s.sup.-1);
and
[0020] the padding further comprises an intermediate portion
between said front portion and said rear portion, and a rigid
element which is mounted on the bottom surface of said intermediate
portion.
[0021] In another aspect, the invention provides a seat proper
having a rigid structure on which such padding is mounted, said
padding being covered with a cover.
[0022] In yet another aspect, the invention provides a seat proper
having a rigid structure on which such padding is mounted, said
padding further comprising an intermediate portion between said
front portion and said rear portion, and said rigid structure
further comprising a rigid element disposed facing said
intermediate portion of said padding.
BRIEF DESCRIPTION OF THE DRAWING
[0023] Other characteristics and advantages of the invention appear
from the following description of one of the embodiments thereof,
given by way of non-limiting example and with reference to the
accompanying drawing.
[0024] In the drawing:
[0025] FIG. 1 is an overall view of a motor vehicle seat comprising
a seat proper provided with padding of the invention, a seat back,
and a headrest; and
[0026] FIG. 2 is a longitudinal section view of the padding of the
seat proper of the seat of FIG. 1.
MORE DETAILED DESCRIPTION
[0027] In the various figures, like references designate elements
that are identical or similar.
[0028] FIG. 1 shows a motor vehicle seat 1 that, in a manner known
per se, is made up of a seat proper 2 supporting a seat back 3 that
itself supports a headrest 4.
[0029] The seat back 3 is, for example, mounted to pivot about the
pivot axis A (FIG. 2) on the seat proper 2.
[0030] The seat proper 2 is itself constituted by a framework (not
shown) over which elastic suspension webbing 5 is tensioned. The
webbing supports padding 6 which is itself covered with a trim
cover 7 suitable for being sat upon by a passenger of the motor
vehicle on board which the seat 1 is installed.
[0031] The padding 6 extends longitudinally along the axis (x)
relative to the direction in which the seat extends between a front
end 8 remote from the seat back 3 and a rear end 9 close to said
seat back. The seat proper can thus be subdivided into three
portions, namely a rear portion 6a, an intermediate portion 6b, and
a front portion 6c, along the axis (x) between the rear end 9 and
the front end 9 of the seat. Each of the portions is of length
approximately equal to one third of the total length of the seat
proper.
[0032] As shown in FIG. 2, the padding has, in particular, a top
face 12 covered with the cover 7 and serving to receive the
occupant by facing mainly upwards in the normal in-use position.
The top face 12 is opposite from a bottom face 13 which faces
towards the floor of the vehicle and is generally retained by the
rigid structure of the seat and/or the suspension webbing 5, at
least when an occupant is seated on the seat.
[0033] The padding 6 comprises two portions of foam 10 and 11, each
of which is made of a respective type of foam. The two portions are
superposed, portion 11 overlying portion 10. At the junction
between the two structures, an intermediate level 15 thus exists in
the padding. Thus, at a given point of the padding along the
longitudinal axis (x), said padding presents a given thickness or
"comfort thickness" h.sub.c of foam 11 above a given thickness or
"stiffening thickness" h.sub.r of foam 10. In the embodiment shown,
each of the two portions extends from the rear end to the front end
of the seat along the longitudinal axis (x) of the seat proper.
[0034] The portion 11 of the padding 6 is made of a soft "comfort"
foam, e.g. made of polyurethane. The portion 10 is made of a
visco-elastic foam. Such a visco-elastic foam stiffens as a
function of the speed at which it is compressed by the passenger in
the seat when the vehicle is subjected to an impact against an
external obstacle. It is thus soft under quasi-static conditions,
at low deformation speeds, and hard at high speeds such as those
imposed by the occupant during an impact.
[0035] The behavior of visco-elastic foam can be characterized by a
stiffening coefficient R. This coefficient is defined as being the
ratio of dynamic lift to static lift, lift being the ratio between
the force to be exerted on the surface of a sample of the foam in
order to obtain 50% deformation of said sample and the area of the
surface of said sample. Dynamic lift is measured for deformation
rates of about 100 s.sup.-1, and quasi-static lift is measured for
deformation rates of less than 0.1 s.sup.-1. The deformation rate
is obtained by dividing the instantaneous speed of the surface of
the foam by the initial thickness of the sample.
[0036] A visco-elastic foam used in the context of the invention
can have a stiffening coefficient R greater than 10. For example,
it is a foam of density in the vicinity 100 kilograms per cubic
meter (kg/m.sup.3) manufactured by Aero E.A.R. Specialty
Composites.TM. under the name CONFOR CF-42 Pink.
[0037] The make-up of the padding is shown in particular in FIG. 2.
The portion 10 that is made of the visco-elastic foam extends under
the portion 11 that is made of conventional soft foam, from the
rear end 9 to the front end 8 of the seat proper. The block of
visco-elastic foam is relatively thin in the rear portion of the
seat proper, with a comfort height h.sub.c representing in the
range 40% of the combined thickness of the two foams to 80% of said
combined thickness, and preferably in the range 50% to 70% and even
more preferably about 60%. Firstly, the presence of visco-elastic
foam in said rear portion makes it possible, by means of the
intrinsic properties of said foam, to restrain the occupant as of
the beginning of the impact. Secondly, the presence of conventional
flexible foam superposed on said visco-elastic foam makes it
possible to guarantee comfort for the occupant during normal
occupancy.
[0038] In the front portion, the visco-elastic foam is in the
majority. The conventional foam presents a thickness h.sub.c of
less than 3 centimeters (cm) therein, and even more preferably less
than 2 cm. Such an arrangement provides sufficient comfort for the
legs of the occupant while also making it possible to restrain the
occupant optimally in the event the vehicle is subjected to frontal
impact.
[0039] The two foams thus have different relative thicknesses
depending on whether they are measured in the front portion or in
the rear portion of the seat proper. In an intermediate portion 6b
between the front portion and the rear portion, the intermediate
level 15 between the conventional foam and the visco-elastic foam
thus presents a rising slope so as to have a face that is almost
normal to the movement of the pelvis of the occupant in the seat
when the vehicle is subjected to a front impact. This considerably
reduces pivoting of the pelvis and therefore reduces the forces
acting on the lumbar region. Since movement of the occupant in the
seat is minimized, other biomechanical criteria (head, chest, lower
limbs) are also reduced.
[0040] Such a seat proper can be implemented in various
manners.
[0041] For example, each of the foams could be made independently,
and then be assembled together by adhesive bonding. Alternatively,
the conventional foam could be overmolded onto the visco-elastic
foam, which would enable the adhesion between the two components to
be improved.
[0042] It is also possible to mold the visco-elastic foam to the
appropriate shape first and then to fasten the cover 7 to the
opposite side of the mold, and finally to inject the conventional
foam. A cover molded directly over the filling 6 is thus obtained.
In which case, in order to guarantee that the molding method
proceeds properly, it is possible to check that the comfort foam 11
presents at least a minimum thickness, e.g. about 2 cm, along the
axis (x).
[0043] Or else, the visco-elastic foam could be bonded by adhesive
directly to the seat structure, whereupon the seat proper is filled
with conventional foam in conventional manner.
[0044] It is optionally possible to add a rigid metal plate 14 to
the bottom face of the padding, in its intermediate portion. Such a
configuration further improves restraint of the occupant by
increasing the reaction area. Alternatively, said plate is a
component element of the seat proper structure. For example, the
plate 14 is secured suitably to the rigid structure of the seat
proper and, in this embodiment, the suspension webbing 5 can then
be tensioned between the rear portion of the framework and the rear
portion of the plate 14, as shown in FIG. 2, as in a half-bucket
structure.
* * * * *