The present invention relates to a seat belt for protecting automobile
passengers during collisions, and more particularly to an air belt with gas releasing
means having a bag-like portion, which is inflated by gas generated by a gas generator.
Japanese Unexamined Patent Publication No.5-85301 describes a typical
inflatable safety harness. Fig.12(a) is a perspective view showing the inflatable
air belt. Fig.12(b) is a cross sectional view of the air belt shown in Fig.12(a)
taken along line B-B.
An air belt device 1 includes a shoulder belt 2, a lap belt 3, a buckle
4, a tongue 5, and an intermediate guide 6. The shoulder belt 2 extends diagonally
from the right side of a passenger's body to the left side. The lap belt 3 extends
across the passenger's body from the right to the left. The buckle 4 is secured
to a floor, or the like of the vehicle body. The intermediate guide guides the shoulder
The shoulder belt 2 has an ordinary belt 2a similar to the conventional
seat belts, and a bag-like belt portion 2b attached to one end of the belt 2a. The
intermediate guide 6 slidably supports the belt 2a. The other end of the belt 2a
is connected to an emergency locking retractor (ELR)7,which is secured to the automobile
body The ELR winds and retracts the belt 2a.
The bag-like belt portion 2b engages with the passenger's body when
in use. It has the tongue 5 at its free end opposite to the end that leads to the
The lap belt 3 is an ordinary and commonly available belt. One end
of the lap belt 3 is connected to the tongue 5 while the other end of the belt is
connected to the ELR 8,which is secured to the automobile body. The buckle 4 has
a gas generator 9 to generate a high pressure gas upon accidents such as collisions.
A passage extends through the tongue 5 and the buckle 4 to allow flow
of gas from the generator 9.
As shown in Fig.12b, the bag-like portion 2b of the shoulder belt
2 includes a folded belt body 2c, as indicated by solid lines, and is enclosed in
a cover 2d, the two edges of which are sewn to each other to form stitches 2e. Accordingly,
the structure of the bag-like portion has a strap-like shape. Upon activation of
the gas generator 9, the stitch 2e tears as the shoulder belt 2 inflates, and the
bag-like portion 2b expands as shown by the double dotted line.
Employing a retractable webbing, which is attached to one end of the
shoulder belt and is wound by a retractor, the air belt device described in Japanese
Unexamined Publication No.5-85301 ensures a large degree of freedom with respect
to the passenger's upper body movement, where the webbing extends and retracts in
response to the movements of the passenger. It would be required, however, that
the winding force of the retractor 7 in the air belt in Japanese Unexamined Publication
No.5-85301 not be too strong to prevent the belt from pressing the passenger with
excessive force. Due to the limitation on the winding force, the gap arises between
the shoulder belt 2 and the passenger's body, requiring further expansion of the
bag-like portion 2b upon a collision.
Accordingly, it is an objective of the present invention to provide
an air belt device that works without applying excessive force on the passenger's
The present invention provides an air belt device. The air belt device
includes an inflatable air belt and a gas generator for supplying gas to the air
belt to inflate the same. The air belt has a bag-like belt folded in a strip-like
state and a cover for covering the bag-like belt. The air belt device being characterized
in that the gas releasing means gradually releases the residual gas in the air belt
after the inflation of the air belt by the gas generator.
The gas releasing means gradually releases the gas from the air belt
to reduce the impact that applies on the passenger upon a collision. FR 2 520 238
A discloses a gas releasing system whereby one end of the air belt includes a piston
attached to the vehicle. When high forces acts on the belt vents are freed and gas
The invention, together with objects and advantages thereof, may best
be understood by reference to the following description of the presently preferred
embodiments together with the accompanying drawings in which figure 11 discloses
the present invention.
- Fig.1 is a perspective view of an automobile seat with an air belt device.
- Fig.2 shows various components of an air belt Fig.3 shows an air belt according
to the present invention, shown as inflated;
- Fig.4 shows different weaving patterns of a knit cover according to the present
- Fig.5 shows the structures of a tongue and a buckle according to the present
- Fig. 6 shows the tip arrangement of an buckle according to the present invention;
- Fig.7 is a perspective view of a buckle and a tongue according to the present
invention, connected to each other;
- Figs.8 are cross-sectional views of a buckle and a tongue connected to each
- Fig.9 shows another arrangement of a buckle and a tongue connected to each other;
- Fig.10 shows the gas flow direction in the arrangement shown in Fig.9;
- Fig.11 shows the structure of a connection of a tongue and a buckle used in
- Fig.12 shows a prior art air belt device;
- Figs.13(a) and 13(b) are comparative pictures of an air belt, showing the air
belt under normal conditions and the belt that is inflated; and
- Figs.14(a) and 14(b) are comparative pictures of another air belt, showing the
air belt under normal conditions and the belt that is inflated.
Fig. 1(a) is a perspective view showing an automobile seat with an
air belt device. Fig. 1(b) is an perspective view of the air belt device. Fig. 2(a)
is a plane view showing the region around the joint between a shoulder belt and
a lap belt, and Fig. 2 (b) is a plane view showing a bag-like belt portion. Figs.
2(c), 2(d), 2(e) are cross-sectional views taken along lines C-C, D-D, E-E, respectively
in Fig. 2(a). Fig. 3(a) is a plane view showing the shoulder belt that is inflated.
Fig. 3(b) is a plane view of the bag-like portion that is inflated. Figs. 3(c) and
3(d) are cross-sectional views taken along lines C-C and D-D respectively in Fig.
3(a). Fig. 4 shows weaving patterns of an air belt cover.
Since the air belt device is essentially the same as the air belt
device shown in Fig. 12 except for a bag-like portion 2B that comprises a shoulder
belt 2, the arrangements of the air belt 2B will mainly be discussed.
As can be seen in Figs. 2 and 3, the air belt 2B includes a bag-like
belt 10 and a tubular knit cover 12 enclosing the bag-like belt 10. The bag-like
belt 10 has a greater width in the part that fits to the passenger's body over the
region from the chest to abdomen. The enlarged portion is folded on top of itself
to form a long band shape as shown in Fig 2.
The knit cover 12 has considerable elasticity in the direction perpendicular
to the belt's longitudinal direction whereas it virtually doesn't expand longitudinally.
The weaving patterns of the knit cover are shown in Figs. 4(a), 4(b) where Fig.
4(a) shows a simple warp knit pattern and Fig. 4(b) shows a pattern into which inlay
threads are introduced to increase the strength and allow the thinner structure.
Either pattern can be used in the present invention. The knit cover 12 is made virtually
unexpandable in the longitudinal direction by applying the thermal expansion process.
The air belt 2B and lap belt 3 are sewn to each other. Both the bag-like
belt 10 and knit cover 12 are sewn to the lap belt 3. The knit cover 12 is sewn
to a webbing 2a as well as to a tongue 5 to reduce the tension that acts on the
Since all the other features of the embodiment but the points described
above are essentially the same as the air belt device shown in Fig. 12(a), the air
belt 2B inflates when a gas generator 9 is activated with the tongue 5 engaging
with the buckle 4. Upon the activation of the gas generator 9, the knit cover 12
contracts in the longitudinal direction of the air belt 2B, causing the belt 2B
to tightly fit on the passenger.
Figs. 13 and 14 show how the knit cover 12 contracts longitudinally
when the air belt 2B, or bag-like belt 10 inflates. As was mentioned above, the
knit cover 12 is made virtually unexpandable in the longitudinal direction of the
belt by means of the thermal expansion process. When the belt 10 inflates, the knitted
loops of the knit cover 12 expand in the direction perpendicular to the longitudinal
direction of the belt. This shortens the knit cover 12 longitudinally, and consequently
the air belt 2B.
Embodiments of a tongue and a buckle will now be described with reference
to Figs. 5 through 11.
Fig. 5(a) is a cross-sectional view showing a tongue 14 and a buckle
16. Fig. 5(b) is a cross-sectional view taken along line B-B in Fig. 5(a). Fig.
6 is a perspective view of the upper part of the embodiment. Fig. 7 is a perspective
view showing the whole of the tongue and buckle joined together. Figs. 8(a) and
8(b) are enlarged cross-sectional views of the joint.
The tongue 14 has a tongue base 18, a seal 20, a tongue plate 24,
an anchor 26, a ring 28, a plastic cover 32, and so on. The tongue base 18 has an
internal cavity. The seal 20 closes the front end of the tongue base 18. The tongue
plate 24 and anchor 26 are connected to the tongue base 18 by connecting pins 22.
The ring 28 attaches the air belt 2B to the tongue base 18. The plastic cover 32
encloses the tongue base 18. The seal 20 is provided with a tear line 33.
When the tongue plate 24 is inserted into the buckle 16 through a
port 34 ( Fig. 6 ), a latching pin of a latch mechanism 38 inside the buckle 16
is locked in a latching hole 36. By pressing a button 40 on the buckle 16, one can
unlock the latch and subsequently release the tongue plate 24 from the buckle 16
with a help of a spring.
The anchor 26 has a port 42 through which the tip of the lap belt
3 is inserted and is connected to the anchor 26.
The buckle 16 has a shell comprising a housing 46, on the top surface
of which are provided the port 34 for the insertion of the tongue plate 24 and a
gas port 48.
The gas port 48 is sealed with the seal 50 having a tear line 52.
Inside the housing 46 are provided a duct 56 and an inflator 58. A
flap 54 is pivotally supported at an end of the duct 56 and can be opened.
When the inflator 58 is activated, the flap 54 pushes the seal 50,
causing the seal 50 to tear apart along the tear line 52. Subsequently, the seal
20 breaks apart along the tear line 33 and the gas is supplied to the air belt 2B,
inflating the air belt 2B immediately.
Though the embodiment features the seal 50 that is inclined to prevent
dust from accumulating on it, it is also possible to have a seal 50A with a level
upper surface as shown in Figs. 9 and 10.
Fig. 9 shows a tongue and a buckle under normal operation, and Fig.
10 shows the condition where the inflator is activated. Figs. 9(a) and 10 (a) are
perspective views showing upper parts of the buckle 16'. Figs. 9(b) and 10(b) are
cross-sectional views showing the joints between the tongue and buckle.
In Figs. 9 and 10, it can be seen that a cylinder 60 with a flap 62
is placed in the buckle under the seal 50A. The cylinder 60 is connected to a duct
56 via a stopper 64. The other reference numbers in Figs. 9 and 10 correspond to
analogous parts in Figs. 6 and 8.
When the inflator 58 is activated, the cylinder 60 moves forward (upward).
This breaks the seal 50A and subsequently, the seal 20. The flap 62 then opens up
in the tongue base 18 to permit the gas flow into the air belt 2B. At this point,
flaps 20F and 50F resulting from the breakage of the seals 20 and 50A cover the
inner surface of the tongue base 18 at its entrance, preventing gas leakage.
Figs. 11(a), 11(b), and 11(c) are cross-sectional views of the present
invention of a tongue and a buckle. In this embodiment, vents 70 are further provided
to the embodiment described in Figs. 9 and 10. The vents are formed at the tip of
the tongue. Upon the activation of the inflator, flaps 20F and 50F cover up the
vents 70 as shown in Fig. 11(b), allowing the gas to flow into the air belt 2B and
inflate it. As the amount of the gas generated by the inflator decreases, the pressure
inside the air belt 2B exceeds the pressure of the incoming flow, which causes the
flaps 20F and 50F to move back to their original positions. Consequently, the vents
70 open up to let the gas in the air belt 2B out gradually. The gradual release
of the gas from the belt minimizes the impact that applies on the passenger's body
when the body is pressed against the belt upon a collision.
As described above, the air belt device according to the present invention
provides an air belt that can comfortably be fastened on the passenger's body while
it protects the passenger upon collisions. The impact applied on the passenger's
body can be reduced significantly by providing vents in the tongue to gradually
release the gas after the completion of the belt inflation.