Land vehicles – Wheeled – Attachment
Reexamination Certificate
1998-08-25
2001-03-27
Mai, Lanna (Department: 3619)
Land vehicles
Wheeled
Attachment
C280S743100, C280S739000
Reexamination Certificate
active
06206409
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATION
This application is based upon and claims priority from Japanese Patent Application No. H. 9-246121 filed on Aug. 26, 1997, the contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an air bag folded and contained in an air-bag system which is mounted on a vehicle and is used for passenger protection. In particular, the present invention relates to an air bag system which can develope the air bag not in a straight thin shape toward a passenger but in a round shape immediately after an inflator supplies gas into the air bag.
2. Description of the Related Art
Conventionally, an air bag system, as shown in
FIG. 21
, for protecting a passenger is known (Japanese Patent Application Laid-Open No. H.8-268198). In this air bag system
200
, a base plate
21
made of metal is attached to a boss plate of a steering wheel (not shown) via a bracket or the like. An inflator attachment hole (not shown) is formed in the base plate
21
. An inflator (not shown) is fit in the inflator attachment hole from a lower side of the base plate
21
in FIG.
21
. On an upper side face of the base plate
21
, a folded air bag
24
is attached. The folded air bag
24
is covered by a lapping sheet member
25
, whereby the shape of the folded air bag
24
is maintained. A plurality of holes
25
d
is formed at each end of the lapping sheet member
25
. The lapping sheet member
25
is fixed to the base plate
21
by inserting rivets into the holes
25
d
and holes formed in the base plate
21
. A tear line
25
c
is formed at a substantially center part of the lapping sheet member
25
.
Since the shape of the folded air bag
24
is maintained, when the folded air bag
24
is contained in a pad of the steering wheel, the pad of the steering wheel is prevented from expanding due to a restoring force of the folded air bag
24
. Furhter, when the air bag
24
is developed, the lapping sheet member
25
is fractured at the tear line
25
c
due to pressure applied from the developing air bag
24
.
However, according to the conventional air bag system as described above, a passenger may be strongly hit by the developing air bag
24
.
FIGS. 22A
to
22
D are schematic views illustrating a developing state of the air bag
24
contained in the pad
20
in a stepwise manner. The air bag
24
is first folded in a straight thin shape and then the both sides
24
c
of the straight thin shape are further folded plural times in perpendicular to a longitudinal direction of the straight thin shape. The air bag
24
thus folded is covered by the lapping sheet member
25
and is contained in the pad
20
(FIG.
22
A).
When the inflator
80
is ignited and a gas produced by the inflator
80
flows into the air bag
24
upon detection of a vehicle collision, a part
24
b
of the air bag
24
in the vicinity of the inflator
80
expands due to pressure of the gas. As a result, the air bag
24
presses the pad
20
from the inside thereof (FIG.
22
B). When the pressure applied from the air bag
24
to the pad
20
reaches a predetermined value, the pad
20
and the lapping sheet member
25
are fractured at tear lines
20
a
and
25
c,
respectively (FIG.
22
C). As a result, a force for maintaining the shape of the folded air bag
24
is released at one time. For this reason, the air bag
24
is firstly developed in such a manner that side portions
24
c
of the air bag
24
folded in the straight thin shape rapidly project toward the passenger by energy of the gas stored in the part
24
b
of the air bag
24
(FIG.
22
D), and then the air bag
24
is developed in a round shape.
As described above, according to the conventional air bag system, the side portions
24
c
of the air bag
24
vigorously project toward the passenger, that is, the air bag
24
is developed in a long thin shape toward the passenger. Such a developing form of the air bag
24
is not desirable because the developing air bag may injure the passenger.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an air bag system which can develop an air bag in an ideal shape.
In order to achieve the above-mentioned object, according to the present invention, an air bag system comprises an air bag having an opening through which gas is supplied. The air bag is folded in a predetermined polygonal shape and is then contained in a pad. Further, an expansion restraining member is provided in the air bag system. The expansion restraining member temporarily holds a peripheral portion such as a corner portion, side portion, tip portion or edge portion of the folded air bag so as to suppress rapid expansion thereof when the air bag is deployed. As a result, because the expansion of the peripheral portion of the folded air bag is delayed, it is possible to prevent the air bag from deploying in the straight thin form toward a passenger. That is, the air bag can be deployed in a round shape from its center portion when the gas is supplied into the air bag. Therefore, the air bag system according to the present invention can protect the passenger more reliably.
The expansion restraining member may be formed in a ring shape and may be fit to the corner portion of the folded air bag.
The expansion restraining member of a strap-like shape can temporarily hold the corner portion or the tip portion of the folded air bag by fixing both ends of the expansion restraining member to any one of the air bag itself, a retaining member for retaining the air bag, and a fixture such as a case used for attaching the air bag system to a vehicle.
When the expansion restraining member is disposed around the folded air bag while passing through a substantially center portion of the air bag, a tear line is preferably formed in the expansion restraining member. In this case, the expansion restraining member can maintain the shape of the folded air bag. Further, because the tear line is formed in the expansion restraining member, when pressure applied from the air bag to the expansion restraining member reaches a predetermined value, the expansion restraining member is reliably torn at the tear line. As a result, even if the expansion restraining member is disposed around the center portion of the air bag, the air bag is certainly deployed.
It is to be noted that, when the expansion restraining member is disposed around the center portion of the air bag, the torn expansion restraining member temporarily holds the corner portion or the tip portion of the air bag.
REFERENCES:
patent: 5350188 (1994-09-01), Sato
patent: 5498023 (1996-03-01), Adams et al.
patent: 5498031 (1996-03-01), Kosugi
patent: 5560648 (1996-10-01), Rhule et al.
patent: 5865466 (1999-02-01), Yamamoto et al.
patent: 5899495 (1999-05-01), Yamamto et al.
patent: 3027291 (1996-05-01), None
patent: 8-268198 (1996-10-01), None
Fujioka Minoru
Kato Hirokazu
Koujiya Mutsumasa
Ozaki Tadashi
Denso Corporation
Jasmin Lynda
Mai Lanna
Pillsbury Madison & Sutro LLP
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