AIR-BAGGED SEAT

Abstract: An air bag storage portion (22a) of a cover member (25) that covers a seat back (22) is formed by sewing up a seat-back front cover element (25a), a side cover element (25b), etc. An air bag module (30) is provided with a casing (31) that contains an air bag (32) and an inflator (33) therein. The casing (31) includes a casing body (31a), which is fixed on a seat back frame (23), and a lid (31b) that is swingably provided on the casing body (31a) and situated between the casing body (31a) and the side cover element (25b). An extending portion (46) is formed on a corner portion (45) of the front part of the lid (31b) to which injection nozzles (34) of the inflator (33) is directed, extending forward to cover the corner portion (45).

Description: D E S C R I P T I O N AIR-BAGGED SEAT Technical Field This invention relates to an air-bagged seat provided with a side air bag capable of effectively protecting a user when a vehicle is subjected to a lateral force of impact. Background Art An air bag that is mounted in a vehicle such as an automobile is caused instantaneously to bulge by means of gas that is generated by an inflator in case of a collision. The inflated air bag restrains a user from undergoing a second collision with some interior members. To cope with a head-on collision, the air bag may be effectively located in front of the user, that is , in a center pad of a steering wheel , or near a glove box in front of a passenger seat. A side impact can be effectively tackled by a so-called side air bag that is incorporated in a seat back or the like. For example, a conventional side-air-bagged seat 1 shown in FIG. 6 has an air bag module 4 incorporated in a side portion 3 of a seat back 2 that is nearer to a door. An inflator 5 is actuated in response to a signal delivered from a sensor when the vehicle is subjected to a side impact, whereupon the air bag 6 is inflated with gas that is generated by the inflator 5. The seat back 2 includes a frame 7, pad 8, cover member 9, etc. As the air bag 6 unfolds, thread 11 in a sewing portion 10 between a seat-back front cover element 9a and a side cover element 9b is broken by pressure that acts thereon from inside the cover member 9. The air bag 6 bulges forward (in the direction indicated by arrow F) from the seat back 2 through the broken portion, as indicated by two-dot chain line (shown in FIG. 6), and unfolds into a shape such that it can protect the flank, temple, etc. of the user. The air bag 6 is stored together with the inflator 5 in a box-shaped casing 15. The casing 15 is provided with a casing body 15a fixed to the frame 7 and a lid 15b disposed on the side of the side cover element 9b of the casing body 15a. The lid 15b is swingable around a hinge portion 16. The lid 15b can be kept on in a manner such that retaining portions 17 such as hooks on the front end of the casing body 15a are anchored individually to receiving portions 18 that are formed on the lid 15b, as shown in FIG. 7. The air bag 6 in this air bag module 4 unfolds when the lid 15b is taken off as the air bag 6 inflates, as shown in FIG. 8. Generally, in consideration of structural requirements for the inflator 5, injection nozzles 5a of the inflator 5 are located in the upper or lower part of the casing 15, as shown in FIG. 9. As the lid 15b is taken off, therefore, that part of the lid 15b which is situated near the nozzles 5a (e.g., upper part of the casing 15) tends to swing open first. Accordingly, a corner portion C of the lid 15b abuts against the side cover element 9b (shown in FIG. 6) in advance of other regions, so that the side cover element 9b may possibly tear as the air bag 6 unfolds. In this case, the unfolding pressure of air bag 6 cannot easily act on the sewing portion 10, so that the unfolding performance of the air bag 6 may possibly be influenced. Accordingly, the object of the present invention is to provide an air-bagged seat in which a cover member can be prevented from being torn by a lid of an air bag module when an air bag unfolds, so that the air bag can display proper unfolding performance. Disclosure of Invention In order to achieve the above object, according to the present invention, there is provided air-bagged seat having an air bag module in a seat back, in which a cover member for covering an air bag storage portion of the seat back includes a seat-back front cover element and a side cover element sewn together, the air bag module is provided with a casing containing an air bag and an inflator therein, the casing includes a casing body, fixed on the side of a frame of the seat back, and a lid swingably provided on the casing body, situated between the casing body and the side cover element, and having a front side adapted to swing open toward the side cover element when the air bag unfolds, and an extending portion extending forward along the side cover element is formed in a position on the front part of the lid corresponding to the injection nozzles of the inflator. According to the air-bagged seat of the present invention, gas jetted out from the nozzles of the inflator is introduced into the air bag in case of a collision. The air bag is inflated with the gas, and the lid of the casing is swung open. Since that part of the lid which is situated near the nozzles tends to swing open first, the portion near the nozzles is directed to the side cover element first. According to the present invention, the wide-area extending portion is provided in that part, so that stress concentration can be restrained so that the side cover element can be prevented from tearing even if the lid abuts against the side cover element. The air bag unfolds toward a sewing portion between the seat-back front cover element and the side cover element. Since thread in the sewing portion is broken as this air bag unfolds steadily in a regular direction, so that the shock of a second collision between a user and interior members can be eased by the air bag. The air bag stated herein is a member that can be inflated like a bag with gas, such as nitrogen gas . It is to be understood that any kinds of gases may be used for inflation. Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter. Brief Description of Drawings The accompanying drawings , which are incorporated in and constitute a part of the specification, illustrate presently preferred embodiments of the invention, and together with the general description given above and the detailed description of the preferred embodiments given below, serve to explain the principles of the invention. FIG. 1 is a cross-sectional view of part of an air-bagged seat according to an embodiment of this invention; FIG. 2 is a perspective view of the air-bagged seat shown in FIG. 1; FIG. 3 is a perspective view of an air bag module used in the air-bagged seat shown in FIG. 1; FIG. 4 is a side view of the air bag module shown in FIG. 3; FIG. 5 is a perspective view of the air-bagged seat shown in FIG. 1 with its air bag unfolded; FIG. 6 is a cross-sectional view of part of a conventional air-bagged seat; FIG. 7 is a perspective view of an air bag module used in the air-bagged seat shown in FIG. 6; FIG. 8 is a perspective view of the air bag module shown in FIG. 7 with its air bag unfolded; and FIG. 9 is a side view of the air bag module shown in FIG. 7. Best Mode of Carrying Out the Invention An embodiment of this invention will now be described with reference to FIGS. 1 to 5. A side-air-bagged seat 20 shown in FIGS. 1 and 2 is applicable to a front seat of an automobile. The seat 20 is provided with a seat cushion 21 and a seat back 22. The seat back 22 is provided with a seat back frame 23, a pad 24 formed of, e.g., polyurethane foam, and a cover member (front seat trim cover) 25 that externally covers the seat back frame 23, pad 24, etc. The cover member 25, which constitutes a covering of the seat back 22, is formed by cutting a cover element of, e.g., artificial leather into a given shape and sewing it. The artificial leather is a cover element obtained by coating the outer surface of knitted fabric for use as a back fabric base with an elastomer layer. Natural leather or woven fabric may be used as a cover element for the cover member 25. A side portion 22a of the seat back 22 functions as an air bag storage portion. Part of the cover member 25 that covers the side portion 22a includes a seat-back front cover member 25a for use as a first cover element and a side cover element 25b for use as a second cover element. These cover elements 25a and 25b are sewn together at a sewing portion 26 by means of sewing thread 27. The seat-back front cover element 25a constitutes the front face of the side portion 22a, while the side cover element 25b constitutes a side face of the seat back 22. The cover member 25 that covers the side portion 22a may be formed by combining the seat-back front cover element 25a, side cover element 25b, and some other cover elements. A bracket 28 is fixed to the lateral of the seat back frame 23 by welding or the like. The bracket 28 includes a mounting plate 28a having a shape such that it extends along an air bag module 30, which will be described below. The air bag module 30 (shown in FIG. 3) is incorporated in the side portion 22a that, out of two opposite side portions 22a and 22b of the seat back 22, is nearer to a door. The air bag module 30 is provided with a box-shaped casing 31, an air bag 32 stored flat in the casing 31, an inflator 33 for generating inflator gas such as nitrogen gas, etc. The casing 31 is fixed to the mounting plate 28a of the bracket 28 of the seat back frame 23. In consideration of structural requirements for the inflator 33, injection nozzles 34 of the inflator 33 are located in the upper part of the casing 31, as shown in FIG. 4. As shown in FIGS. 1 and 3, the casing 31 is provided with a casing body 31a fixed to the seat back frame 23 and a lid 31b attached to the casing body 31a and situated between the casing body 31a and the side cover element 25b. In the case of this embodiment, a bolt 36 is provided on the rear part of the casing body 31a. The casing body 31a is fixed in a predetermined position on the bracket 28 by passing the bolt 36 through a hole in the mounting plate 28a and fastening a nut 37 to the bolt 36 in an engaged manner. The inflator 33 is connected with an ignition system, which includes a sensor for detecting a collision of a vehicle, a power source (not shown), etc. The lid 31b is swingable around a hinge portion 40 that is situated at the rear end portion of the casing 31. The lid 31b can be kept on the casing body 31a in a manner such that retaining portions 41 such as hooks on the front end portion of the casing body 31a are anchored individually to receiving portions 42 such as holes in the front end portion of the lid 31b. As the air bag 32 unfolds, the lid 31b swings open in the direction of arrow A in FIG. 1, that is, toward the side cover element 25b or in a direction such that the front side of the lid 31b leaves the casing body 31a. An extending portion 46 is provided at an upper corner portion 45 of the front part of the lid 31b to which the nozzles 34 of the inflator 33 are directed. The extending portion 46 has a substantially flat shape, spreading forward and vertically to cover the corner portion 45. When the air bag module 30 is stored in a predetermined position in the side portion 22a, the extending portion 46 is interposed between the corner portion 45 and the side cover element 25b. The extending portion 46 extends forward along the side cover element 25b. The extending portion 46 has an area wide enough to prevent the side cover element 25b from undergoing excessive stress concentration such that the side cover element 25b tears if the extending portion 46 abuts against the side cover element 25b when the air bag 32 unfolds, that is, when the lid 31b is taken off. The following is a description of the operation of the air-bagged seat 20 with the air bag module 30. When the vehicle receives a lateral force of impact, the inflator 33 is actuated in response to a signal delivered from the sensor for detecting a collision of the vehicle, whereupon the inflator gas such as nitrogen gas is jetted out from the nozzles 34 of the inflator 33. The jetted gas is ejected into the air bag 32 in a manner such that the direction of its ejection is regulated by the casing body 31a and the lid 31b. When the air bag 32 starts to be inflated with the gas jetted out by the inflator 33, the receiving portions 42 of the lid 31b are disengaged from the retaining portions 41 of the casing body 31a. Thus, the front side of the lid 31b is opened as the lid 31b is taken off, whereupon the air bag 32 unfolds ahead of the casing 31. As the lid 31b unfolds, that part of the lid 31b which is situated near the nozzles 34 of the inflator 33 (upper corner portion 45 in the case of FIG. 4) tends to swing open first. Possibly, therefore, the corner portion 45 may abut against the side cover element 25b in advance of other regions. However, the corner portion 45 of the lid 31b is provided with the wide-area extending portion 46. If the corner portion 45 engages the side cover element 25b as the lid 31b swings open, therefore, excessive stress concentration on a contact spot between the side cover element 25b and the lid 31b can be avoided. Thus, the side cover element 25b can be restrained from tearing, and the unfolding force of the air bag 32 acts directly on the sewing thread 51 in the sewing portion 50. Accordingly, the sewing thread 51 in the sewing portion 50 breaks without fail, whereupon the air bag 32 spreads out in the direction indicated by arrow F, as indicated by two-dot chain line in FIG. 1. FIG. 5 shows the air bag 32 in its unfolded state. Since the unfolded air bag 32 is located in a space between the flank of a seated user's body and an inner side wall of the vehicle body, the shock of a second collision between the user and the inner side wall of the vehicle body can be eased. According to the embodiment described above, the nozzles 34 of the inflator 33 are located in the upper part of the casing 31, so that the extending portion 46 is provided on the upper corner portion 45 of the casing 31. In the case where the nozzles 34 are located in the lower part of the casing 31, for example, however, it is advisable to provide the extending portion 46 on a lower corner portion 45a of the casing 31. In short, it is necessary only that the extending portion 46 be located near the nozzles 34 of the inflator 33, that is, at that corner portion of the front end portion of the lid 31b that starts to swing open first. In the embodiment described herein, the air bag module 30 is supposed to be incorporated in the seat back 22 of a passenger seat in a right-hand wheel vehicle. According to this invention, however, the same effect as aforesaid can be obtained by incorporating an air bag module 30 similar to the one according to the foregoing embodiment in a door-side portion of the seat back of a driver's seat, for example . Industrial Applicability In the air-bagged seat according to this invention, the lid of the air bag module can be prevented from tearing the cover member such as the side cover element to cause the air bag to unfold, so that the air bag can display proper unfolding performance. The air-bagged seat of this invention is suited for use in a vehicle such as an automobile. Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents .

Claims: C L A I M S 1. An air-bagged seat (20) having an air bag module (30) in a seat back (22), characterized in that: a cover member (25) for covering an air bag storage portion (22a) of said seat back (22) includes a seat-back front cover element (25a) and a side cover element (25b) sewn together; said air bag module (30) is provided with a casing (31) containing an air bag (32) and an inflator (33) therein; said casing (31) includes a casing body (31a), fixed on the side of a frame (23) of the seat back (22), and a lid (31b) swingably provided on the casing body (31a), situated between the casing body (31a) and said side cover element (25b), and having a front side adapted to swing open toward the side cover element (25b) when the air bag unfolds; and an extending portion (46) extending forward along said side cover element (25b) is formed in a position on the front part of said lid (31b) corresponding to the injection nozzles (34) of said inflator (33). 2. An air-bagged seat (20) according to claim 1, wherein said extending portion (46) is provided so as to cover a corner portion (45) of the front part of the lid (31b) to which the nozzles (34) of said inflator (33) is directed.

Inventors: MURATA YOSHIAKI, TAKAZAWA SYUNJI, MURATA, YOSHIAKI, TAKAZAWA, SYUNJI
Applicants: MURATA YOSHIAKI, NHK SPRING CO LTD, TAKAZAWA SYUNJI, MURATA, YOSHIAKI, NHK SPRING CO., LTD., TAKAZAWA, SYUNJI
Application year: 1999
Main classification: B60R21
IPC codes: B60R21