Land vehicles – Wheeled – Attachment
Reexamination Certificate
1998-07-07
2001-01-23
Swann, J. J. (Department: 3611)
Land vehicles
Wheeled
Attachment
C280S731000, C280S732000, C280S743100
Reexamination Certificate
active
06176509
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an air bag device which blows gas from an inflator into a folded air bag so as to inflate to unfold the air bag, and also to a method for accommodating the air bag in the air bag device.
2. Description of the Related Art
Recently in a vehicle, an air bag device is used which is mounted in a portion fixed to a vehicle body, for example, a steering wheel in an interior of the vehicle and which inflates to unfold an air bag due to a large acceleration being applied to the vehicle.
As the above-described air bag device, there is known, for example, the structure illustrated in
FIGS. 19
to
21
. In the air bag device
10
shown in these figures, an inflator
14
which is a gas generator is disposed at the center of a retainer
12
which is a supporting plate, and an air bag
18
is disposed to enclose gas ejecting holes
16
of the inflator
14
and is also covered with a module cover
20
. In order that the air bag
18
thus disposed be provided in a narrow space formed between the inflator
14
and the module cover
20
, the air bag
18
is accommodated compactly in a folded state.
Conventionally, as a method of folding the air bag
18
, there is known a folding method which is called a so-called roll winding method. In this roll winding method, the air bag
18
of a circular flat surface in a developed state is, first, wound into a roll from both ends thereof in the diametrical direction to a front surface which faces a vehicle occupant in a state in which the air bag
18
inflates to unfold and where an aperture
18
A into which the inflator
14
is inserted is not formed, so as to be folded up to become elongate (rectangular), thereby forming a first folding portion
24
.
Next, the air bag
18
folded substantially into a rectangle is wound into a roll from both ends thereof to a rear surface, which is opposite to the front surface, with the aperture
18
A formed thereon and a pair of roll portions
22
are thereby formed as post-folding portions.
The pair of roll portions
22
are each wound to the position near the aperture
18
A and folded toward the front surface with no aperture
18
A formed and in a direction opposite to the direction in which each roll portion
22
is wound, to form reversed portions
23
. As a result, the folding method of roll winding type as shown in
FIG. 19
is completed. In the roll winding system, the pair of roll portions
22
which are the post-folding portions are disposed adjacently so as to contact each other, and the first folding portion
24
which is a portion of the air bag
18
and folded preceding the pair of roll portions
22
is positioned between the pair of roll portions
22
and the inflator
14
.
As shown in
FIG. 19
, in the air bag device in which the air bag
18
is accommodated in a state of being wound into rolls, when an acceleration sensor (not shown) detects a large acceleration of a predetermined value or more applied to the vehicle, the inflator
14
is actuated to generate gas. The gas generated in the inflator
14
blows out from the gas ejecting holes
16
to push to expand the first folding portion
24
. As a result, as illustrated in
FIG. 20
, the pair of roll portions
22
are pushed by the expanded first folding portion
24
to break the module cover
20
along a groove-shaped break portion
26
, and therefore, the pair of roll portions
22
are pushed out. Moreover, when the first folding portion
24
continues to expand by gas continuously ejected from the gas ejecting holes
16
of the inflator
14
, the pair of roll portions
22
located at the front side in the direction in which the first folding portion
24
expands (i.e., the direction indicated by arrow A in
FIG. 20
) are pushed out by the first folding portion
24
, and as a result, the pair of roll portions
22
moves rapidly toward the front side of the air bag device
10
, i.e., in the direction indicated by arrow A and is thereby unfolded. Subsequent to this operation, when the air bag
18
is filled with gas ejected from the inflator
14
, the air bag
18
inflates to unfold in the direction indicated by arrow B in
FIG. 21
so as to be brought into a final expanding state having a slightly compressed spherical configuration.
Thereafter, the air bag
18
gradually becomes deflated in such a manner that gas is let out from an air hole.
In the above-described folding system in which the air bag
18
is wound into a roll, during an expanding operation of the air bag
18
, the roll portions
22
which are the post-folding portions move toward the front side indicated by arrow A preceding the first folding portion
24
so as to expand toward the front side of the air bag device, and thereafter, as gas is fed from the first folding portion
24
of the air bag
18
to the roll portions
22
, the roll portions
22
are each pulled back in a direction opposite to that indicated by arrow A (i.e., toward the rear side of the air bag device
10
), and simultaneously, inflate to unfold in the directions indicated by arrows B (i.e., the left-and-right directions of the air bag device
10
). As a result, the air bag is subjected to the expanding process so as to be brought into a final expanding state to have a compressed spherical configuration. For this reason, it is not possible that the entire air bag
18
expands uniformly through the expanding process in such a manner as to enlarge a ring of a concentric circle from the central portion thereof.
SUMMARY OF THE INVENTION
In view of the above-described circumstances, it is an object of the present invention to provide an improved air bag device which allows an entire air bag to expand uniformly in radial and forward directions of the air bag, i.e., in three-dimensional manner with respect to the center thereof, all through an expanding process of the air bag and also provide a method for accommodating the air bag in the air bag device.
According to the first aspect of the present invention, there is provided an air bag device which allows an air bag accommodated in a folded state to inflate to unfold due to gas ejected from an inflator, wherein: the air bag is accommodated in the air bag device in such a manner that the flat, unfolded air bag is folded up to form an elongated folding body; the elongated folding body is folded from both longitudinal-directional ends to wrap these ends inside a roll so as to form a pair of roll-shaped folding bodies; and a preceding expanding and first folding portion is formed in a portion of the previously-folded elongated folding body, which is a space between the pair of roll-shaped folding bodies, the preceding expanding and first folding portion being provided to start expanding first when gas is ejected from the inflator.
In an air bag device of the present invention, it is preferable that an aperture through which gas ejected from the inflator is introduced is formed at a central portion of the flat, unfolded air bag and the air bag may be folded from both sides with the aperture disposed as the center so as to form the elongated folding body and the pair of roll-shaped folding bodies.
Further, it is preferable that the transverse dimensions of each of the pair of roll-shaped folding bodies and the transverse dimensions of the preceding expanding and first folding portion in the longitudinal direction of the elongated folding body are substantially equal to each other. The transverse dimension of the preceding expanding and first folding portion may be substantially equal to the outer diameter of the inflator.
With the above-described structure, when the inflator starts to eject gas so as to inflate to unfold the air bag, the preceding expanding and first folding portion first starts to expand to come out in a space between the pair of roll-shaped folding bodies. Subsequently, when the precedingly expanding and first folding portion further inflates to unfold, the pair of roll-shaped folding bodies are caused to inflate to unfold toward both longitudinal-directional ends of the pr
Kawaguchi Teruhiko
Maeda Itoshi
Cole Thomas W.
Kabushiki Kaisha Tokai-Rika-Denki-Seisakusho
Lum L.
Nixon & Peabody LLP
Swann J. J.
LandOfFree
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