GB2265338A

GB2265338A - Cover for vehicle air bag.

Info

Publication number: GB2265338A
Application number: GB9305451A
Authority: GB
Inventors: Kazuo Watanabe; Takayasu Zushi; Yoshiyuki Baba
Original assignee: Takata Corp
Current assignee: Takata Corp
Priority date: 1992-03-25
Filing date: 1993-03-17
Publication date: 1993-09-29
Anticipated expiration: 2013-03-17
Also published as: KR100260874B1; GB2265338B; DE4308908A1; GB9305451D0; JPH05270339A; KR930019472A

Description

TITLE OF THE INVENTION

MODULE COVER FOR AN AIR BAG DEVICE 2265338 FIELD OF THE INVENTION

The present invention concerns a module cover for an air bag device for a passenger's seat disposed in an instrument panel ahead of the passenger's seat, as well as a module cover f or an air bag device f or a driver ' s seat, the device being attached to a steering wheel of an automobile. More in particular, it relates to a module cover improved such that the module cover is accurately torn along a tear line upon expansion of the air bag.

DESCRIPTION OF THE RELATED ART

In the air bag device for use with a passenger's seat of the aforementioned type, an air bag and an inflator are attached to an air bag retaining member (sometimes also referred to as a casing or a container), and a module cover is further attached so as to cover the opening of the casing. The module cover is sometimes also referred to as a cover door or deployment door. Upon collision of the automobile, the inflator is actuated to expand the air bag and the module cover, being pushed by the expanding air bag, opens to the inside of the cabin and the air bag expands toward the cabin.

Description will be made of the outlined construction and the operation of an air bag device for use with a passenger's seat in the prior art with reference to Fig. 5 through Fig. 7.

1 Fig. 5 is a schematic perspective view of an air bag device for use with a passenger's seat in the prior art. Fig. 6 is a cross sectional view taken along lines VI-VI in Fig. 5 and Fig. 7 is an explanatory view of the operation. In an air bag device 10 for use with a passenger's seat an air bag 14 is contained being folded in a casing 12. The casing 12 has an inflator 16 disposed for expanding the air bag 14. The casing 12 has an opening situated at the front or upper side disposed towards the cabin. The opening is covered with a lid or a module cover 18. The lid or module cover 18 has a structure in which a metal reinforcing plate 18b is disposed inside (or at the back) of a main body 18a made of a synthetic resin. An opening 29 is disposed in an instrument panel 22 of a vehicle for attaching an air bag device.

For attaching the lid or module cover 18 to the casing 12, attaching members 24, 26 protrude from the rear face of the lid or module cover 18 and the attaching members 24, 26 are secured by means of rivets or bolts 28, 30 to the casing 12. respectively.

The module cover 18 has a f irst tear line 31 extending in the lateral direction of the car body and second tear lines 32, 34 extending in the longitudinal direction of the car body. The tear lines 32, 34 are f ormed parallel to but somewhat spaced apart from the attaching members 24, 26.

If a vehicle carrying the air bag device 10 has a collision, the inflator 16 actuates to expand the air bag 14, and the air bag 14 pushes the module cover 18. Thus, the first tear line 31 is torn at first and then the tearing propagates 2 to the tear lines 32, 34, so that the module cover 18 opens like a door as shown in Fig. 7. Thus, the air bag 14 expands into the cabin.

Description will now be made next to the air bag device for use with the driver's seat and the module cover therefor in the prior art.

As shown in Fig. 8, an air bag device 42 for use with the driver's seat is disposed in the central portion of an automobile steering wheel 40. In the air bag device 42 for use with the driver's seat, an inflator and an air bag are attached to an air bag retaining member (generally referred to as a retainer) and a module cover 44 is mounted so as to cover them. As shown in Figs. 9 and 10, the module cover 44 has engaging portions 48, 50, 52, 54 formed on the lateral side of the module cover such that they can be aligned with spokes 46 of the steering wheel 40.

Tear lines are formed in the module cover 44 such that they are torn along predetermined lines upon actuation of the air bag.

The tear lines comprise a pair of second tear lines 60, 62 formed in the longitudinal direction of the car body along right and left side edges of the cover 44 and a first tear line 58 formed at the centre of the cover 44 in the lateral direction of the car body. When the longitudinal or lateral direction of the car body is referred to, it is assumed that the steering wheel is in such an attitude for advancing the vehicle straight forward. The tear lines 60, 62 are formed along but spaced apart slightly from attaching members 64, 66 3 f or securing and attaching the module cover 44 to the retainer (not illustrated).

The tear line is sometimes f ormed as a continuous or intermittent groove along the expected portion f or tearing as shown in Fig. 11. The depth of the groove may be increased at a predetermined interval. Further, in a cover of a dual layered laminate structure comprising a hard layer and soft layer, a slit may be formed to the hard layer along the line expected for tearing.

If an automobile carrying such an air bag device has a collision, the inflator (gas generator) actuates to expand the air bag. Then, the module cover 44 is at first torn along the first tear line 58 and, further, the tearing propagates along the second tear lines 60, 62, so that the module cover is torn wide open and the air bag expands into the cabin.

As described above in the existing air bag device, upon expansion of the air bag, the first tear line is at first torn. and successively, the tearing propagates to the second tear lines. so that the module cover is torn wide open.

The f irst tear line and the second tear line intersect each other at their joint portion substantially perpendicular to each other. Therefore, it is a concern that the tearing propagating along the f irst tear line may propagate due to inertia in the module cover in the direction towards the sides of the car body.

4 OBJECT AND SUMMARY OF THE INVENTION

It is an object of the present invention to provide a module cover for an air bag device in which tearing propagating along the first tear line reliably changes the direction of propagation at the joint portion with a second tear line and tearing occurs successively along the second tear line.

The module cover for an air bag device according to the present invention is a module cover for an air bag device for use in an automobile for covering an air bag secured and attached to an air bag retainer and folded. Attaching members for the module cover protrude from the rear face of the module cover for attaching the module cover to the air bag retaining member. Tear lines for tearing the module cover upon expansion of the air bag extend at the back of the module cover. The tear lines comprise a first tear line extending in the lateral direction of the car body of the automobile and a second tear line contiguous with the first tear line and extending in the longitudinal direction of the car body. The attaching member at least partially extends in the longitudinal direction of the car body of the module cover.

The second tear line is formed directly along the base end of the attaching member in the longitudinal direction of the car body on the central side of the module cover. The joining portion between the first tear line and the second tear line is disposed at the positions directly along the base end.

In the module cover for the air bag device according to the present invention as described above, tearing that propagates along the first tear line, upon reaching the joining portion between the f irst tear lines and second tear line, the attaching member f orms a wall in front of the direction of tearing propagation. Therefore, propagation of tearing along this direction is inhibited by the wall-like attaching member, so that successive tearing occurs only to the second tear line. Since the second tear line is directly along the base end of the attaching member, tearing propagates smoothly while being guided along the attaching member.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a perspective view illustrating a module cover of an air bag device for use with a passenger's seat in a preferred embodiment according to the present invention; Fig. 2 is a cross sectional view taken along line II-II in Fig. 1; Fig. 3 is a perspective view illustrating a module cover of an air bag device f or use with a driver's seat in a preferred embodiment according to the present invention; Fig. 4 is a cross sectional view taken along line IV-IV in Fig. 3; Fig. 5 is a perspective view illustrating an existing air bag device for use with a passenger's seat; Fig. 6 is a cross sectional view taken along line VI-VI in Fig. 5; Fig. 7 is a perspective view illustrating the operation of the air bag device in Fig. 5; Fig. 8 is a perspective view illustrating an existing air bag device for use with a driver's seat; 6 1 Fig. 9 is a perspective view illustrating a module cover of an existing air bag device for use with a driver's seat; Fig. 10 is a perspective view illustrating an existing air bag device for use with a driver's seat as viewed from the back; and Fig. 11 is a cross sectional view taken along line X1-XI in Fig. 10.

PREFERRED EMBODIMENTS Description will now be made to preferred embodiments with reference to the drawings. Fig. I is a perspective view illustrating, as viewed from the back, a module cover of an air bag device for use in a passenger's seat in a preferred embodiment according to the present invention and Fig. 2 is a cross sectional view taken along line II-II in Fig. 1.

In this embodiment, attaching members 241, 261 are disposed at the back of a module cover 18A and other attaching members 361, 38' are disposed so as to joint the attaching members 241, 261 to each other. A f irst tear line 311 is formed along the base end of the attaching member 381. Further, second tear lines 321, 341 are formed directly along the base ends of the attaching members 241, 261.

In the thus constituted module cover 18A. when the air bag is expanded and the module cover 18A is urged at the back, the first tear line 31' at first starts tearing and the tearing propagates rightward and leftward along the attaching member 38'. Then, when the tearing arrives at the joining portions 32'a, 34'a with the tear lines 321, 34', the attaching members 7 241, 261 form a wall in front of the direction of propagation. Therefore, the tearing reliably changes direction and rapidly tears the second tear lines 321, 341. Accordingly, the module cover 18A accurately tears along the tear lines 311, 32, 341.

Fig. 3 is a perspective view illustrating. as viewed from the back, of a module cover 44A of an air bag device for use with a driver's seat in one embodiment according to the present invention. Fig. 4 is a cross section taken along line IV-IV in Fig. 3.

In this embodiment, second tear lines 601, 621 are disposed so as to be directly along the base ends of attaching members 64', 661. Other constituents are the same as those in Fig. 10 and corresponding portions carry the same reference numerals each designated with a sign 11,11, for which duplicate explanation will be omitted.

Also in this embodiment, when the air bag is expanded to urge the module cover 44A from the back,, the first tear line 581 at first starts tearing, and the tearing propagates in right and left directions. Then, when the tearing arrives at the joining portions 601a, 621a with the tear lines 601, 621, the attaching members 641,, 661 form walls in front of the direction of propagation. Accordingly, tearing rapidly changes its direction of propagation in a right angle and then the second tear lines 601, 621 are torn. As a result, the module cover 44A is torn accurately along the tear lines 581 r 601 621.

8 As has been described above in the module cover of the air bag device according to the present invention, in the case where the air bag device is operated to expand the air bag, the module cover is torn accurately along the first tear line and the second tear line, so that the air bag can expand in the cabin rapidly and reliably.

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Claims

WHAT IS CLAIMED IS 1. A module cover of an air bag device for use in an

automobile for covering an air bag secured and attached to an air bag retainer and folded, in which attaching members protrude from the back of the air bag module cover for attaching said module cover, and tear lines extend at the back of said module cover for tearing said module cover upon expansion of said air bag, and said tear lines comprise a first tear line extending in the lateral direction of the body of the automobile and a second tear line contiguous with said first tear line and extending in the longitudinal direction of the car body, wherein at least a portion of said attaching members extend in the longitudinal direction of the car body, said second tear line is formed directly along the base end on the central side of the module cover of said attaching member in the longitudinal direction of the car body, and the joining portion between said f irst tear line and the second tear line is disposed at a position directly along said base ends.
2. A module cover of an air bag device comprising: a lid for covering an air bag attached to an air bag retaining member, attaching members standing vertically f rom the back of said lid so as to attach said lid to said air bag retaining member, and having at least a pair of said attaching members along at least a pair of lateral edges of said lid, at least one first tear line extending at the back of said lid in the direction of connecting said pair of attaching members to each other, in which both ends of said at least one first tear line reaches as far as the base ends of said attaching members on the central side of the module cover, and at least one second tear line disposed at the back of said lid directly along the base ends of said pair of attaching members and being contiguous with said at least one first tear line.
3. A module cover of an air bag device as defined in claim 2, wherein the air bag device is for use with a passenger's seat and the attaching members are disposed at the back of the lid of the module cover so as to constitute a rectangular frame-like configuration.
4. A module cover of an air bag device as defined in claim 3, wherein f irst tear lines are disposed along f irst and second attaching members opposite to each other and second tear lines are disposed along the base ends of third attaching members f or connecting said first and second attaching members.
5. A module cover of an air bag device as defined in claim 2, wherein the air bag device is for use with a driver's seat and the attaching members are disposed at the back of the lid of the module cover so as to constitute a generally rectangular frame-like configuration.
6. A module cover of an air bag device as defined in claim 5, wherein the first tear lines are disposed along the first and the second attaching members opposed to each other, and a second tear line is disposed so as to connect each of the mid points for the first tear lines.
7. A module cover of an air bag device as defined in claim 2, wherein the tear lines are grooves.
8. A module cover of an air bag device as defined in claim 3, wherein the second tear lines are disposed along first and second attaching members opposite to each other and a f irst tear line is disposed along the base end of a third attaching member for connecting said f irst and second attaching members.
9. A module cover of an air bag device as defined in claim 5. wherein the second tear lines are disposed along the first and second attaching members opposite to each other, and a first tear line is disposed so as to connect each of the second tear lines intermediate the ends.
10. A module cover of an air bag device substantially as hereinbefore described with reference to the accompanying description and Figures 1 and 2; or Figures 3 and 4 of the drawings.

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