Method of folding an air bag

Abstract: To provide a method of folding an air bag which can provide suitable deployment of the air bag to secure sufficient ability for restraining an occupant and which is improved to smoothly deploy the air bag. [Means to achieve the object] In a method of folding an air bag comprising a front panel 3 on an occupant side and a rear panel 5 on a side opposite to the occupant side, the method includes a step of forming a looseness 11 vertically or laterally extending about the center thereof on the side opposite to the occupant side. The method includes a step of forming rolls 21, 23, 25, 27 by rolling up upper, lower, left, and right side edges of the air bag or folding them in bellows.

Description: The present invention relates to a method of folding an air bag which is deployed to protect an occupant when a vehicle comes into collision. More particularly, the present invention relates to a method of folding an air bag which can provide suitable deployment of the air bag to secure sufficient ability for restraining an occupant and which is improved on the smoothness of the deployment. The present invention can be applied to any of air bags for a driver, a front passenger, and a rear passenger. A method of folding an airbag according to the features of the preamble of claim 1 is known for example from DE-A-25 36 933. A method of folding an air bag in which the side edges of the air bag are folded toward an occupant has the following problems. In the initial stage of the deployment, a central portion of the air bag which is in contact with an inflator is rapidly inflated so that a bulk of folded portions is pushed out of the cover toward the occupant. In the final stage of the deployment, the air bag is inflated forward at a high speed so that the bulk of folded portions is further pushed out. There is a fear that the occupant is subjected to pressure due to the folded body of the air bag. The object of this invention is to provide a method of folding an air bag which can provide suitable deployment of the air bag to secure sufficient ability for restraining an occupant and which is improved on the smoothness of the deployment. This object is achieved with the features of the claims. This invention enables the folded air bag to have a loosing portion vertically or laterally extending thereby providing suitable deployment of the air bag to secure sufficient ability for restraining an occupant and improving the smoothness of the deployment. In the method of folding the air bag mentioned above, it is preferable that side edges of the air bag are rolled up or folded in bellows on the side opposite to the occupant side. The air bag can be folded in a square or rectangular shape so that the air bag can be securely accommodated in the box-like cover. In addition, the air bag is deployed relatively entirely equally from the central portion thereof. The rolls or folded bodies of the side edges are prevented from advancing directly toward the occupant. The second embodiment of the present invention provides a method of folding an air bag comprising a front panel on an occupant side and a rear panel on the side opposite to the occupant side, which is characterized by comprising (a) a step of forming a loosing portion vertically or laterally extending about the center of the air bag, and (b) a step of rolling up upper, lower, left, and right side edges of the air bag or folding them in bellows on the side opposite to the occupant side. The loosing portion about the center of the air bag prevents the air bag as a whole from easily rapidly projecting, so that the air bag starts to inflate from the central portion thereof gradually. The works of the edges being rolled up or folded in bellows are the same as the case of the aforementioned first embodiment. Hereinafter, the present invention will be described with reference to attached drawings. Figs. 1(A)-1(F') are views illustrating the folding process according to the method of folding the air bag of the embodiment of the present invention. Figs. 2(A)-2(C) are views illustrating the configurations of the air bag during the deployment In the order of time; Fig. 2(A) shows the state before the deployment of the air bag, Fig. 2(B) shows the state in the initial stage of the deployment, and Fig. 2(C) shows the state in the final stage of the deployment. Fig. 3 is a side view showing the alternative example of the method of folding the air bag of the embodiment shown in Figs. 1(A)-1(F). Fig. 4 is a side view showing the alternative example of the method of folding the air bag of the embodiment shown in Figs. 1(A)-1(F'). Figs. 1(A) through 1(F') are views illustrating process of folding an air bag according to one embodiment of the present invention. Fig. 1(A) is a view of the air bag 1, which is substantially circular in its plan view, taken at a front panel 3 side. The air bag 1 comprises the front panel 3 and a rear panel 5 which are strongly connected to each other around the peripheries thereof (for example, by sewing, adhesion, or welding). The rear panel 5 has a gas inlet 7 formed in the center thereof. Connected to the gas inlet 7 via a retainer (not shown) is an inflator (not shown) which generates deployment gas. Figs. 1(B), 1(B') show a first stage of folding process where the air bag 1 is folded to have a loosing portion 11 vertically extending at the center thereof. Fig. 1(B) is a plan view and Fig. 1(B') is a side view. That is, the air bag 1 is provided with two folded lines 15, 15' on both sides of the vertical center thereof to extend parallel to each other and the both sides of the air bag are folded along the folded lines 15, 15' toward the center of the air bag 1. Then, both side edges outside of the folded lines 15, 15' are folded (along folded lines 13, 13') toward the outside. In this way, the vertically extending loosing portion 11 is formed at a side opposite to an occupant side. As shown in Figs. 1(C), 1(C') and 1(D), 1(D'), the upper and lower side edges of the air bag 1 are rolled up on the side opposite to the occupant side to form rolls 21, 23. Figs. 1(C'), 1(D') are side views. As shown in Fig. 1(D'), in which the left side is the occupant side and the right side is the side opposite to the occupant side, the lower roll 21 is rolled toward the center thereof in the counter-clockwise direction and the upper roll 23 is rolled toward the center thereof in the clockwise direction. This is because the air bag expands in such a manner that the trucks of the center of each roll becomes an arched line (see Fig. 2(C)) when the rolls become loose during the deployment of the air bag. After that, as shown in Figs. 1(E), 1(E'), 1(F), 1(F'), the left and right side edges of the air bag 1 are rolled up on the side opposite to the occupant side to form rolls 25, 27 so that the rolls 25, 27 are positioned on the central loosing portion 11. As a result of this, the air bag 1 is formed in a small square as shown in Fig. 1(F). In this state, the retainer 31 and the inflator 33 are connected to the air bag 1 and are accommodated in a cover 35. The description will be made as regard to the configurations of the air bag folded as shown in Figs. 1(A) through 1(F') during its deployment. Figs. 2(A) through 2(C) are views showing the configurations of the air bag of Figs. 1(A)-1(F') in the order of time. Fig. 2(A) shows the state before the deployment of the air bag, Fig. 2(B) shows the state of the initial stage of the deployment, and Fig. 2(C) shows the state of the final stage of the deployment. In the state before the deployment shown in Fig. 2(A), the air bag 1 which is folded in a square or rectangular shape is accommodated in the box-like cover 35. The gas inlet 7 positioned toward the loosing portion 11 at the central portion of the air bag 1 is fixed to the inner periphery of the retainer 31. The inflator 33 is disposed in the center of the retainer 31. As the inflator 33 is ignited, the loosing portion 11 at the central portion of the air bag 1 is first inflated while the side rolls 26, 27, 21,23, still stay in the cover 35 as shown in Fig. 2(B); in the final stage of the deployment, the central portion of the air bag 1 is further inflated and the folded portion or the rolls of the side edges are accordingly inflated so that the deployment of the air bag 1 is entirely relatively equal and smooth. Hereinafter, an alternative example of the folding method according to the embodiment of Figs. 1(A)-1(F') will be described. Though the side edges of the air bag are rolled up in the embodiment of Figs. 1(A)-1(F'), the right and left, upper and lower side edges may be folded in bellows 21', 25', 27' as shown in Figs. 3 and 4. According to the method of folding the air bag of the embodiment, the combination of vertical, lateral, and vertical directions or the combination of lateral, vertical, and lateral directions is employed as the folding and/or rolling directions so that the loosing portion exists on the air bag in the vertical direction or the lateral direction. Since the side edges are rolled up or folded in bellows on the side opposite to the occupant side, the air bag can be folded in a square or rectangular shape so that the air bag can be securely accommodated in the box-like cover. In addition, the air bag is deployed relatively entirely equally from the central portion thereof. The rolls or folded bodies of the side edges are prevented from advancing directly toward the occupant. The loosing portion extending laterally or vertically across the air bag on the side opposite to the occupant side prevents the air bag as a whole from easily rapidly projecting, so that the air bag starts to inflate from the central portion thereof.

Claims: A method of folding an airbag comprising the steps: a) forming a loosing portion (11) at a rear side opposite to an occupant side by folding two sides of the airbag (1) relative to the centre area towards a front side (3) of the airbag (1), characterized by folding again the two sides of the first and counter first directions away from the centre area so that parts of the two sides are placed on the centre area, said loosing portion (11) extending along second and counter second directions perpendicular to the first and counter first directions in a centre area of the airbag (1), b) rolling first edge portions of the airbag (1) in the second and counter second directions at the rear side to form rolls (21, 23), the lower roll (21) is rolled toward the centre area in the counter-clockwise direction and the upper roll (23) is rolled toward the centre-area in the clockwise direction and to form a middle area in the centre area, and c) rolling second edge portions of the airbag in the first and counter first directions at the rear side to form rolls (25, 27) positioned on the central loosing portion (11) and to allow a part of the middle area to face the occupant. A method of folding an airbag according to claim 1, wherein said folding the airbag includes rolling an edge portion of the airbag or folding the edge portion of the airbag in bellows. A method according to any of claims 1 or 2, wherein said second edge portions are located on the loosing portion (11).

Inventors: ATO TADAYUKI, KUSAKA SYUJI, ATO, TADAYUKI, KUSAKA, SYUJI
Applicants: TAKATA CORP, TAKATA CORPORATION
Application year: 1999
Main classification: B60R21
IPC codes: B60R21