STRUCTURE AND METHOD FOR FOLDING AIR BAG

Abstract: A method of folding an air bag, comprising winding a head protecting portion (B) a plurality of times with its protective surface (Sb) positioned on the inner side, and stuffing the resultant head protecting portion (B) into a chest protecting portion (A) with the part (C) joined to the head protecting portion (B) of the chest protecting portion (A) also stuffed into the chest protecting portion (A) at the same time.

Description: Technical Field The present invention relates to a folded structure and a folding method for an airbag. Background Art As an airbag for vehicles, there is an airbag for lateral collision adapted, upon a lateral collision of a vehicle, to spread forwards from a side of the backrest to protect a passenger. (A similar art is disclosed in Japanese Patent Application Laid-Open Publication No. 9-136598.) When spread, such a type of airbag has a generally L-shape external configuration partitioned by an internal partition cloth into a head protecting upper portion and a chest protecting lower portion. The airbag has a proximal end provided with an inflator, and discharged gas from a discharge port at a side of the inflator first enters the chest protecting portion, spreading this forwards, and further rushes through a communication hole across the partition cloth inside the head protecting portion, spreading this upwards. Such an airbag for lateral collision needs to have a chest protecting portion quickly spread into a relatively narrow spacing between a passenger and a side wall of a vehicle body, as well as an implementation to avoid, when spreading, interferences such as with the vehicle body' s side wall, for example. The action and speed when such an airbag is spread depends on how to fold the airbag. A folded structure of an L-shaped airbag and a method of folding this airbag, according to the preambles of claims 1 and 4, are known from WO 97145 86 A. To this point, it is desirable to propose a folded structure and a folding method for an airbag, allowing an improved spreading speed, as well as for the action of spread to be smooth without failure due to an interference with a vehicle body side wall. The present invention has been achieved with such points in view, to provide a folded structure and a folding method for an airbag, permitting an improved spreading speed and a smooth spread action. Disclosure of Invention The present invention in an aspect thereof provides a folded structure for an airbag with a generally L-shape spread external configuration having a chest protecting portion and a head protecting portion provided with protection surfaces for a chest. protection and a head protection when spread, in which the head protecting portion is rolled a plurality of times with the protection surface thereof inside, and the head protecting portion is pushed inside the chest protecting portion. In another aspect, the invention provides a folding method for an airbag with a generally L-shape spread external configuration having a chest protecting portion and a head protecting portion provided with protection surfaces for a chest protection and a head protection when spread, comprising rolling the head protecting portion a plurality of times with the protection surface thereof inside, and pushing the head protecting portion inside the chest protecting portion. According to the aspects of the invention, an airbag with a generally L-shape spread external configuration has a chest protecting portion and a head protecting portion provided with a "protection surface for a head protection or for a chest protection when spread" (hereinafter sometimes called "passenger side surface" or simply "passenger side"), and when folding, the head protecting portion is rolled a plurality of times with the passenger side inside, and the head protecting portion configured neat by folding into such a rolled form is pushed inside the chest protecting portion. When the airbag spreads, from the chest protecting portion to be spreading at a high speed the rolled form of the head protecting portion is sprung out at a higher speed and, like a cloth roll forcibly thrown on a floor for example, agilely unfolds straight in an extending direction along a vehicle body side wall or the like with a width of a roll diameter, and even if more or less obstacles be present at the back side, rolls to spread over them, concurrently inflating for development. Accordingly, even in the case of development of the airbag in a relatively narrow spacing between a passenger and the vehicle body side wall, the head protecting portion is spread smooth and swiftly without being impeded by interference with interior appliances or the like on the vehicle body side wall. Further, also the chest protecting portion connected to the head protecting portion spreads swiftly, allowing for the passenger to be protected in an initial phase of a lateral collision of vehicle. It is noted that the chest protecting portion may preferably be rolled a plurality of times with the protection surface thereof inside, whereby the chest protecting portion having a rolled form of the head protecting portion pushed therein is rolled plural times with its passenger side inside, and in addition to the effect described, a final fold size of the airbag becomes reduced, to be favorable for installation in a backrest which has a small accommodation space. Further, a part of the chest protecting portion connected to the head protecting portion may preferably be pushed inside the chest protecting portion, whereby a portion of the chest protecting portion at the head protecting portion side is pushed, together with the head protecting portion pushed therein, inside the chest protecting portion, and a fold size of an entirety of the airbag becomes reduced, allowing for the chest protecting portion to spread with ease in a small spacing between the passenger and the vehicle body side wall and further for the head protecting portion to be sprung out with an increased initial speed, permitting the more rapid development. Brief Description of Drawings Fig. 1 is a side view illustrating an airbag apparatus in accordance with a first embodiment of the invention. Fig. 2 is a side view of an airbag illustrating a first step of folding. Fig. 3 is a side view of the airbag illustrating a second step of folding. Fig. 4 is a side view of the airbag illustrating a third step of folding. Fig. 5 is a side view of the airbag illustrating a fourth step of folding. Fig. 6 is a section along a line VI-VI of Fig. 5. Fig. 7 is a side view of the airbag illustrating a fifth step of folding. Fig. 8 is a side view of the airbag illustrating a sixth step of folding. Fig. 9 is a side view of the airbag illustrating a seventh step of folding. Fig. 10 is a side view of the airbag illustrating a final fold state. Fig. 11 is a side view of an airbag illustrating a fifth step of folding according to a second embodiment of the invention. Fig. 12 is a side view of the airbag illustrating a sixth step of folding. Fig. 13 is a side view of the airbag illustrating a final fold state. Best Mode for Carrying Out the Invention There will be described below preferred embodiments of the invention with reference to the drawings. Figs. 1 to 10 show a first embodiment of the invention. First, with reference to Fig. 1, a structure of an airbag apparatus will be described. Designated by reference numeral 1 is a backrest of a right front seat, which has at its right end an airbag module 2 incorporated therein. The air bag module 2 has an airbag 3 and an inflator 4 accommodated therein. The airbag 3 is housed in the airbag module 2, in a later-described fold state. The airbag 3 is adapted, upon a lateral collision of a vehicle, for a spreading inflation between a passenger and a vehicle body side wall, to protect the passenger. The airbag 3 has a generally L-shaped external configuration when spread, which is separated into a chest protecting lower portion A and a head protecting upper portion B by provision of a cloth 5 as an internal partition. A communication hole 6 is formed at a rear side of the partition cloth 5. At a side of the inflator 4, in a lower end part, there is formed a discharge port 7, and discharged gas G from the discharge port 7 first enters the chest protecting portion A, causing the chest protecting portion A to spread forwards, and thereafter the gas G in the chest protecting portion A is introduced through the communication hole 6 inside the head protecting portion B, causing the head protecting portion B to spread upwards. Next, there will be described how to fold the airbag 3 inside the airbag module 2, with reference to Figs. 2 to 10. At a first step, as illustrated in Fig. 2, a part of the head protecting portion B is pushed inside the chest protecting portion A from position of the partition cloth 5. This step is for correcting an orientation of the head protecting portion B slightly inclined rearwards, and constitutes a preparation step to facilitate a rolling operation thereafter. In the drawings, designated by a reference character Sa is a passenger side surface of the chest protecting portion A, and a Sb is a passenger side surface of the head protecting portion B. At a second step, as illustrated in Fig. 3, a rearwardly projecting part 8 of the head protecting portion B is folded back at a fold line L1 onto the passenger side. This step also constitutes a preparation step to facilitate the rolling operation thereafter. At a third step, as illustrated in Fig. 4, the head protecting portion B configured into a substantially rectangular form through the first and second steps is rolled five times in accordance with five enroll lines as references, toward the passenger side, so that the head protecting portion B is configured in a roll. At a fourth step, as illustrated in Figs. 5 and 6, the head protecting portion B rolled up in a roll is pushed inside the chest protecting portion A. Fig. 6 illustrates a section taken along line VI-VI of Fig. 5. At a fifth step, as illustrated in Fig. 7, a lower corner part 9 of the chest protecting portion A in the fourth step is pushed between the head protecting portion B of a rolled form and the chest protecting portion A at an external side of the vehicle, from a fold line L3 in Fig. 5. At a sixth step, as illustrated in Fig. 8, a part C of the chest protecting portion A connected to the head protecting portion B and ranging to a push-in line L4 is pushed, together with the head protecting portion B of a rolled form, inside the chest protecting portion A, further from the push-in line L4. At a seventh step, as illustrated in Fig. 9, an upper end part 10 of the head protecting portion B rolled up in a roll is folded back at a fold line L5 onto a passenger side. By the foregoing steps, a final fold state of the airbag 3 is achieved as illustrated in Fig. 10. According to the embodiment, the head protecting portion B is rolled a plurality of times (five times in this case) toward the passenger side (at the third step), and when the airbag 3 inflates, the head protecting portion B is caused to spread in a rolling manner along the vehicle body side wall. Accordingly, a spreading inflation of the head protecting portion B is achieved smooth without being impeded by interference with interior appliances or the like on the vehicle body side wall. Further, the head protecting portion B rolled up in a roll is pushed inside the chest protecting portion A (at the fourth step), and the head protecting portion B rolled in a roll is agilely pushed out of the chest protecting portion A, allowing a spreading inflation as described. Further, a part of the chest protecting portion A at the head protecting portion B side is pushed, together with the head protecting portion B of a roll form, inside the chest protecting portion A, and the chest protecting portion A can spread swiftly in a narrow spacing between a passenger and the vehicle body side wall. In other words, a push-in structure allows a stuffed portion to be directly pushed out as it is, permitting a very fast spreading speed. Accordingly, even in a narrow spacing between a passenger and the vehicle body side wall, the chest protecting portion A can be spread swiftly to ensure protection of a chest of the passenger in an initial phase of a vehicle's lateral collision. Figs. 11 to 13 show a second embodiment of the invention, which will be described below, assuming that there have already been exercised like steps to the first embodiment, up to a fourth step of pushing a head protecting portion B inside a chest protecting portion A. Then, at a fifth step, as illustrated in Fig. 11, an upper corner 11 and a lower corner 12 are folded back at fold lines L6 and L7, respectively, onto a passenger side. At a sixth step, as illustrated in Fig. 12, the chest protecting portion A after the fifth step is rolled five times in accordance with five enroll lines L8 as references, to be wound in a roll. By the foregoing steps, there is achieved a final fold state of an airbag 3 as illustrated in Fig. 13. According to the second embodiment, the head protecting portion B is once rolled up in a roll and pushed inside the chest protecting portion A, like the first embodiment, and additionally thereafter, also the chest protecting portion A, in which the head protecting portion B rolled up in a roll is pushed, is rolled a plurality of times toward the passenger side, and therefore the airbag 3 has a smaller final fold size than the first embodiment. Accordingly, it is favorable for application to a backrest with a small accommodation space. Industrial Applicability According to the invention, a head protecting portion of an airbag is adapted to spread in a rolling manner along a vehicle body side wall, permitting a smooth spreading inflation of the airbag. Accordingly, the invention is extremely useful for an airbag for vehicles.

Claims: A folded structure of an airbag with a generally L-shape spread external configuration having a chest protecting portion (A) and a head protecting portion (B) provided with passenger side protection surfaces (Sa, Sb) for a chest protection and a head protection when spread, characterized in that the head protecting portion (B) is rolled a plurality of times with the protection surface (Sb) thereof on the inside; and the head protecting portion (B) is pushed inside the chest protecting portion (A). A folded structure of an airbag according to claim 1, wherein the chest protecting portion (A) is rolled a plurality of times with the protection surface (Sa) thereof on the inside. A folded structure of an airbag according to claim 1, wherein a part (C) of the chest protecting portion (A) connected to the head protecting portion (B) is pushed inside the chest protecting portion (A). A folding method for an airbag with a generally L-shape spread external configuration having a chest protecting portion (A) and a head protecting portion (B) provided with passenger side protection surfaces (Sa, Sb) for a chest protection and a head protection when spread, characterized by rolling the head protecting portion (B) a plurality of times with the protection surface (Sb) thereof on the inside; and pushing the head protecting portion (B) inside the chest protecting portion (A). A folding method for an airbag according to claim 4, further comprising rolling the chest protecting portion (A) a plurality of times with the protection surface (Sa) thereof on the inside. A folding method for an airbag according to claim 4, further comprising pushing a part (C) of the chest protecting portion (A) connected to the head protecting portion (B) inside the chest protecting portion (A).

Inventors: SASAKI HIROSHI, SEO KASUMI, SUNABASHIRI YUKISADA, SASAKI, HIROSHI, SEO, KASUMI, SUNABASHIRI, YUKISADA, SASAKI, Hiroshi Nissan Motor Co., Ltd., SUNABASHIRI, Yukisada Nissan Motor Co., Ltd.
Applicants: NISSAN MOTOR, NISSAN MOTOR COMPANY, LIMITED
Application year: 1998
Main classification: B60R21
IPC codes: B60R21