GB2265584A

GB2265584A - Cover for vehicle air bag

Info

Publication number: GB2265584A
Application number: GB9306618A
Authority: GB
Inventors: Akira Kokeguchi
Original assignee: Takata Corp
Current assignee: Takata Corp
Priority date: 1992-04-03
Filing date: 1993-03-30
Publication date: 1993-10-06
Also published as: DE4310275A1; SE9300961D0; SE9300961L; GB9306618D0; FR2689470A1; KR930021465A; JPH05278548A

Abstract

A lid 14 is mounted on a casing 10 containing a folded air bag 12 by way of an attaching member 22 with a tear line 38 which cleaves to permit opening of the lid on deployment of the bag. A protrusion 42 on the casing engages a step 40 on the attaching member, for inhibiting the case connecting portion from moving in the forward direction of the casing and thus ensuring that breaking stresses are concentrated at the tear line. <IMAGE>

Description

2265584 STRUCTURE FOR MOUNTING A LID OF AN AIR BAG DEVICE FOR USE WITH A

PASSENGER'S SEAT

Field of the Invention

The present invention concerns a structure for mounting a lid of an air bag for usewith a passenger's seat. More specifically, it relates to a structure for mounting a lid, in which an attaching member capable of tearing for connecting a lid with a casing can reliably be torn upon opening of the lid.

Description of the Related Art

In an air bag device for use in a passenger's seat, an air bag is contained, being folded, in a casing (sometimes also referred to as a container or a retainer) in which a front opening of the casing is covered with a lid. Upon collision of a vehicle, an inflator (gas generator) generates a gas to expand the air bag. The lid, being urged by the expanding air bag, expands intothe cabin of the vehicle.

The lid is connected at one side thereof to a casing by means of an attaching member capable of tearing and connected rotatably at the other side thereof to the casing. When the lid is urged by the air bag, the attaching member capable of t--aring is torn and the lid opens like that a 1 door.

It is necessary that the attaching member capable of tearing usually connects the lid firmly to the container, but the tearing strength is desirably as low as possible so that the air bag expands rapidly.

OBJECT AND SUMMARY OF THE INVENTION

An object of the present invention is to provide a structure for mounting a lid of an air bag device for use with a passenger's seat capable of satisfying such requirements that conflict with each other.

A structure for mounting a lid of an air bag device for use with a passenger's seat in accordance with the present invention comprises a structure for mounting a lid to a front opening of a casing that contains a folded air bag, wherein the lid is mounted at one side thereof to a front edge on one side of the casing rotatably in the opening direction, and connected at the other side thereof to a front edge of the casing on the opposite side opposing to the one side described above by way of an atzaching memb er capable of tearing which is torn upon opening of the lid.

The attaching member comprises a lid connecting portion connected to the lid, a case connecting portion connected to the casing and an intermediate portion for 2 1 joining the lid connecting portion and the case connecting portion, in which the strength of the intermediate portion is lower than that of the lid connecting portion and the case connecting portion.

The easing has a protrusion disposed at the front edge of the abovementioned opposite side that protrudes sideways from the casing, while the attaching member has a step for engaging the protrusion and inhibiting the case connecting portion from moving in the forward direction of the casing.

In the structure for mounting the lid of the air bag device- for use with the passenger's seat in accordance with the present invention, the lid is firmly connected to the casing by way of the attaching member. When the inflator is actuated to urge the air bag in the direction of opening the lid, the step of the attaching member engages the front edge of the casing to inhibit the case connecting portion of the attaching member from moving in the forward direction of the casing. Accordingly, extremely large breaking stresses are concentrated to the attaching member, at intermediate portion near the step, and the intermediate portion is rapidly torn. Accordingly, after the actuation of the inflator, the lid is opened within a short period of time, and the air bag expands to the inside of the vehicle cabin within'a short period of time. Further, a pressure 3 exerted on the inside of the easing and leading to the tearing of the attaching member (primary pressure) can be reduced and the casing suffers from less deformation.

Further, in the structure according to the present invention, stresses are concentrated at the intermediate portion of the attaching member upon expansion of the air bag as described above to facilitate the tearing of the intermediate portion. This means that the lid can be opened rapidly to expand the air bag in the vehicle cabin even if the gas generating pressure. required for the inflator is low. That is, in accordance with the present invention, it is possible to adopt an inflator of a lowergas generation pressure.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a cross sectional view illustrating a structure of a preferred embodiment according to the present invention, Fig. 2 is a cross sectional view of an air bag device for use with a passenger's seat adopting the structure of the preferred embodiment.

Fig. 3 is a perspective view of an attaching member 22.

Fig. 4 is a front elevational view of the attaching member 22.

Fig. 5 is a cross sectional view illustrating a struc ture of another preferred embodiment.

Fig. 6 is a perspective view of an attaching member 50.

PREFERRED EMBODIMENTS Description will now be made to preferred embodiments with reference to the drawings.

Fig. 1 is a cross sectional view illustrating a structure of a preferred embodiment according to the present invention, Fig. 2 is a cross sectional view of an air bag device for use in a passenger's seat adopting the structure of the preferred embodiment, Fig. 3 is a perspective view of an attaching member and Fig. 4 is a front elevational view of the attaching member.

As shown in Fig. 2, an air bag 12 is contained, being folded, to the inside of a casing 10. The front opening of the casing 10 is covered with a lid 14 and an inflator 16 is disposed in a rear portion of the casing 10.

In this embodiment, the lid 14 has a reinforcing plate 18, and a leg member 20 is formed by vertically bending one side of the reinforcing plate 18, and the leg member 20 is secured to the casing 10 by means of a rivet 21. An attaching member 22 is connected to the lid 14 on the side opposite to the leg member 20, and the lid 14 is connected to the casing 10 by way of the attaching member 22.

As shown in Fig. 1 and Figs. 3 and 4, the attaching - member 22 has an Lshaped configuration in its side eleva tional view, in which a lid connecting portion 24 and a case connecting portion 26 extend in the direction perpendicular to each other. The lid connecting portion 24 has a rivet hole 28 formed therein and the lid connecting portion 24 is secured to the lid 14 by means of a rivet 30.

The case connecting portion 26 also has a similar rivet hole 32 formed therein, and the case connecting portion 26 is secured to the casing 10 by means of a rivet 34.

An intermediate portion 36 is formed between the case connecting portion 26 and the lid connecting portion 24. In this embodiment, a tear line 38 is extended in the lateral direction, and the tear line 38 is extended in the direction crossing obliquely to the longitudinal direction from the case connecting portion 26 to the lid connecting portion 24.

At the boundary between the case connecting portion 26 and the intermediate portion 36, a step 40 is disposed along the tear line 38.

A protrusion 42 protruding sideways from the casing 10 is disposed to the front edge of the casing 10, and the step 40 engages the protrusion 42.

In the structure for mounting the lid of the air bag device for use with the passenger's seat having thus been constituted,when the inflator 16 is actuated to discharge 6 a gas and the air bag 12 starts expansion, the lid 14, being urged by the air bag 12, tends to open in the direction of an arrow shown in Fig. 2. Then, in the attaching member 22, since the protrusion 42 and the step 40 are engaged, the case connecting portion 26 can not move in the forward direction of the case 10 (upward in Fig. 1), and breaking stresses are concentrated to the portion of the tear line 38. This rapidly tears the attaching member 22 along the tear line 38, by which the lid 14 opens around the leg member 20 as the center of rotation, and the air bag 12 expands fully into the vehicle cabin.

As described above, since the step 40 of the attaching member 22 engages the protrusion 42, the tear line 38 is torn within a short period of time after the actuation of the inflator to shorten the time from the actuation of the inflator to the completion of the expansion of the air bag. In addition, since the breaking stresses are concentrated to the tear line 38 thereby facilitating the tearing of the attaching member 22, a gas generation pressure required for the infiator 16 may be low.

Further, in this embodiment, since the tear line 38 is extended in the oblique direction as described previously, the step 40 and the protrusion 42 are engaged at one position. That is, the step 40 and the protrusion 42 are engaged only at the right most end shown in Fig. 4.

7 Accordingly, when the lid 14 is urged by the air bag 12, tearing stresses are concentrated to the right end portion of the tear line 38, so that the tear line 38 rapidly starts tearing from the portion on the right end. Therefore, the time from the start of the actuation of the inflator 16 to the completion of the expansion of the air bag can further be shortened.

Fig. 5 is a cross sectional view illustrating a structure of another embodiment according to the present invention and Fig. 6 is a perspective view of an attaching member 50 used in the example shown in FIg. 5. The attaching member 50 comprises a lid connecting portion 52, a case connecting portion 54 and an intermediate portion 56 that connects them. The thickness for each of the lid connecting portion 52 and the case connecting portion 54 is made greater than that of the intermediate portion 56. A step 58 is disposed at the boundary between the intermediate portion 56 and the case connecting portion 54.

The step 58 engages the protrusion 42 of the case 10. Other constitutions or components shownin Fig. 5 are identical with those shown in Fig. 1, in which identical reference numerals illustrate identical portions.

Also in the structure of the embodiment shown in Figs. 5 and 6, when the inflator is actuated and the air bag urges the lid 14, the case connecting portion 54 is 8 inhibited from upward movement in Fig. 5 by the engagement between the step 58 and the protrusion 42, so that large breaking stresses are concentrated to the intermediate portion 56. As a result, the intermediate portion 56 is rapidly torn to open the lid 14. Accordingly, also in this embodiment, the time from the actuation of the inflator to the completion of the expansion of the air bag is shortened, and the gas generation pressure required for the inflator may be low as well.

In the present invention, the attaching member is preferably made of a rubber or synthetic resin.

As has been described above according to the structure for mounting the lid in accordance with the present invention, when the air bag expands to urge the lid, breaking stresses are concentrated to the intermediate portion of the attaching member, so that the attaching member is rapidly torn. Therefore, the time from the actuation of the inflator to the completion of the expansion of the air bag can be shortened and the gas generation pressure required for the inflator can be reduced. In addition, this can also reduce the cost of the inflator assembled in the air bag device.

9

Claims

WHAT IS CLAIMED IS:

1. A structure for mounting a lid of an air bag device for use with a passenger's seat in which a lid is mounted to the front opening of a casing containing a folded air bag, said lid is mounted at one side thereof to a front edge on one side of said casing rotatably in the opening direction and connected at the other side thereof to a front edge of said casing on the side opposite to said one side by way of an attaching member capable of tearing which is torn upon opening of said lid, wherein said attaching member comprises:

a lid connecting portion connected to said lid, a case connecting portion connected to said casing and an intermediate portion connecting said lid connecting portion and said case connecting portion, in which the strength of said intermediate portion is lower than that of said lid connecting portion and said case connecting portion, a protrusion that protrudes sideways from the casing is disposed to the front edge of said casing on said opposite side, and a step is disposed to said attaching member, for engaging said protrusion and inhibiting said case connecting portion from moving in the forward direction of said casing.

2. A structure for mounting a lid of an air bag device as defined in claim 1, wherein a tear line comprising a groove extends in the intermediate portion in a direction transverse to the attaching member.

3.2

3. A structure for mounting a lid of an air bag device as defined in claim 2, wherein the tear line extends in the direction obliquely crossing the longitudinal direction from the case connecting portion to the lid connecting portion.

4. A structure for mounting a lid of an air bag device as defined in claim 2, wherein the step is disposed along the tear line.

5. A structure for mounting a lid of an air bag device as defined in claim 1, wherein the thickness of the intermediateportion is less than that for each of the lid connecting portion and the case connecting portion.

-Q 6. A structure for mounting a lid of an air bag device as defined ift claim 5, wherein a step is disposed at the - 11 boundary between the intermediate portion and the case connecting portion.

7. A structure for mounting a lid of an air bag device as defined in claim 1, wherein the attaching member is made of a rubber.

8. A structure for mounting a lid of an air bag device as defined in claim 1, wherein the attaching member is made of a synthetic resin.

9. A structure for mounting a lid of an air bag device substantially as hereinbefore described with reference to the accompanying description and Figures 1 to 4; or Figures 5 and 6 of the drawings.