Land vehicles – Wheeled – Attachment
Reexamination Certificate
2003-02-03
2004-01-20
Dickson, Paul N. (Department: 3616)
Land vehicles
Wheeled
Attachment
C280S743200
Reexamination Certificate
active
06679522
ABSTRACT:
BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT
The present invention relates to an airbag for protecting an occupant as a result of expanding during an emergency in a vehicle.
In order to protect an occupant during a collision in a vehicle, a driver airbag device, a passenger airbag device, a back-seat airbag device, and a side airbag device are used. Of these various types of airbag devices, the passenger airbag device is accommodated inside an instrument panel disposed at the front side of the vehicle. Of the different types of passenger airbag devices, the type of passenger airbag device which is disposed at a windshield-opposing location of the top portion of the instrument panel is called a top-dash-mount-type passenger airbag device.
Hereunder, a description of an airbag device will be given taking a top-dash-mount-type passenger airbag device as an example.
FIG.
14
(A) is a schematic side view used to illustrate the form of a conventional passenger airbag device when it has finished spreading. FIG.
14
(B) is a front view thereof.
FIG.
15
(A) is a schematic side view used to illustrate the form of the conventional passenger airbag device when a load acts thereupon (that is, when an occupant moves forward). FIG.
15
(B) is a front view thereof.
FIG.
16
(A) is a perspective view showing the conventional airbag in an expanded state. FIG.
16
(B) is a perspective view showing the airbag in a squashed state when a load acts thereupon. FIGS.
16
(C) and
16
(D) are schematic views used to illustrate the characteristics of the squashed state of the airbag when a load acts thereupon.
The passenger airbag device shown in FIGS.
14
(A) and
15
(A) comprises a retainer R disposed at a windshield-opposing location of the top portion of an instrument panel p of a vehicle. Inside the retainer R are disposed an airbag
103
and an inflator I for supplying spread gas into the interior of the airbag
103
. As simply shown in FIG.
16
(A), the airbag
103
is a three-piece bag in which two pieces of side cloths
103
b
are sewed, one at each side of one piece of strip-like central cloth
103
a
interposed therebetween. The airbag
103
has an open end (that is, a gas-circulation hole)
103
c
which is narrowed down thinly at the base of the airbag
103
. The open end
103
c
merges with a space in the inflator I. The airbag
103
is accommodated in a folded state inside the retainer R.
A description of the operation of the passenger airbag device will now be given.
At the time of a collision of a vehicle, spread gas is supplied into the airbag
103
from the inflator I. This causes the airbag
103
to expand in front of an occupant H, as shown in FIGS.
14
(A) and
14
(B). When the spreading of the airbag
103
is completed, the side cloths
103
b
extend in smooth curved forms or substantially straight lines from top to bottom portions thereof, as shown in FIG.
14
(B). Here, the internal pressure or resistance inside the airbag
103
is substantially uniform at the top and bottom portions thereof.
After the airbag
103
has spread, as shown in FIG.
15
(A), the occupant H that moves forward due to inertial force hits the airbag
103
. This causes the airbag
103
to be pushed and squashed as a result of being sandwiched between the instrument panel P and the windshield F and the occupant H. At this time, as shown in FIG.
15
(B), the upper portion of the airbag
103
spreads horizontally by a greater amount than the lower portion thereof. The following factors (1) to (3) cause the airbag
103
to be in a squashed state.
(1) As simply shown in FIG.
15
(B), regarding the areas of the portions of the upper part of the body (from the waist upward) of the occupant H that hits the airbag
103
, the area of the upper portion of the upper body (from the neck upwards) is smaller than the area of the lower portion of the upper body (from the shoulders downward).
(2) Regarding the masses of the portions of the upper body of the occupant H, the mass of the upper portion of the upper body is smaller than that of the lower portion of the upper body.
(3) While the lower portion of the airbag
103
is pushed upward by the knees of the occupant H, the upper portion of the airbag
103
is relatively not pushed.
When an attempt is made to correct the characteristics of the squashed state of the airbag
103
, the output of the inflator I must be set relatively high.
A description of the resistance on the airbag
103
when a load is exerted thereupon will now be given with reference to FIG.
16
.
When the occupant hits the airbag
103
shown in FIG.
16
(A) from the front surface of the airbag
103
, an external force a shown in FIG.
16
(B) acts upon the airbag
103
. As shown in the same figure, this causes the airbag
103
to become squashed while spreading flatly. Here, as shown schematically in FIGS.
16
(C) and
16
(D), the airbag
103
escapes towards a region of lower resistance (that is, in the directions of empty arrows inside the bag
103
), so that the resistance against a load body f becomes smaller, thereby making it easier to squash the bag.
In view of the above-described problems, it is an object of the present invention to provide an airbag which has a more preferable spread form without increasing the output of an inflator.
SUMMARY OF THE INVENTION
To overcome the above-described problems, according to the present invention, there is provided an airbag for protecting an occupant as a result of expanding during an emergency in a vehicle, wherein, in a front form of the airbag at the time of expansion thereof as viewed from the occupant, an inwardly extending depression is formed in a middle portion of a side surface of the airbag as viewed in a vertical direction.
When the occupant collides against the airbag, the depression at the middle portion of the airbag makes it difficult for the gas in the bottom portion of the bag to move upward. Consequently, the resistance at the bottom portion of the bag effectively acts upon the occupant. Therefore, it is possible to provide an airbag which has a more preferable spread form without increasing the output of the inflator.
REFERENCES:
patent: 3879057 (1975-04-01), Kawashima et al.
patent: 5078423 (1992-01-01), Fujita
patent: 5516146 (1996-05-01), Kopitzke
patent: 5669632 (1997-09-01), Johnson et al.
patent: 5678858 (1997-10-01), Nakayama et al.
patent: 6315324 (2001-11-01), Keshavaraj
patent: 03136942 (1991-06-01), None
Dickson Paul N.
Fleming Faye M.
Kanesaka & Takeuchi
Takata Corporation
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