Land vehicles – Wheeled – Attachment
Reexamination Certificate
2003-03-05
2004-04-20
Dickson, Paul N. (Department: 3616)
Land vehicles
Wheeled
Attachment
C280S743100
Reexamination Certificate
active
06722693
ABSTRACT:
The present application claims priority to Japanese Patent Application of Ikeda et al., filed Apr. 2, 2002, under No. 2002-099965, and Japanese Patent Application of Kato et al., filed Apr. 12, 2002, under No. 2002-111057, the entirety of each is hereby incorporated into the present application by this reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an airbag used in a head protecting airbag device to be mounted on an automobile. Specifically, an airbag according to the present invention comprises an airbag body, and a tearable wrapping material for keeping the airbag body in a folded state. The airbag body is folded and housed in the peripheral edge of an opening at the interior side of a vehicular body, and expands and inflates so as to cover the vehicle's interior side of the opening when inflation gas flows thereinto. After folding, the airbag body is wrapped by the wrapping material.
2. Description of Related Art
As disclosed in Japanese Patent Laid-Open No. Hei 11-321532, in the airbag for the head protecting airbag device of this kind in the prior art, a folded airbag body is wrapped by a wrapping material such as a tape member to keep itself in a folded state. Without this wrapping material, the airbag body, after being folded up, returns to the unfolded state and loses its folded-up configuration because of spring-back mechanism. Then the airbag body becomes bulky so that it cannot be mounted on the vehicle.
The wrapping member in the prior art was wound around the airbag body as folded into a generally rod-like shape, along the axis' circumferential direction so as to intersect the axial direction of the airbag body perpendicularly. The folded airbag body was wound at several positions intermittently along its axial direction.
In the airbag in the prior art, more specifically, the portions wrapped by the wrapping member and the portions not wrapped are arranged alternately along the airbag body's axial direction in the wrapping area. This inevitably leaves the portions not wrapped bulging due to the spring-back. Here arises a difficulty in housing the airbag body in a narrow housing portion when mounting on a vehicle.
Here, it is conceivable to wrap the airbag body with a bag-shaped (or cylindrical) wrapping member so that the airbag body may keep its folded-up configuration over its generally entire length. In this case, however, it would be troublesome to insert the folded airbag into the wrapping member if the wrapping member has a small diameter. If the wrapping member has a sufficient diameter, the diameter needs to be reduced after inserting the folded airbag body into the wrapping member. This work has to be applied over the entire length of the airbag body, which is troublesome, too.
Moreover, the smooth expansion and inflation from the wrapped state also needs to be considered as well as compact-wrapping of the airbag body.
SUMMARY OF THE INVENTION
The present invention contemplates to solve the above-specified problems, and therefore, its object is to provide an airbag which is capable of keeping the airbag body in the wrapping area in a compact shape by a simple wrapping work, while securing a smooth expansion and inflation.
The first airbag according to the present invention comprises an airbag body and a tearable wrapping member for keeping the airbag body in the folded state. The airbag body is folded and housed in the opening peripheral edge at the interior side of a vehicular body. The airbag body is wrapped by a wrapping member after being folded in such a manner as to expand and inflate to cover the opening when the inflation gas flows thereinto. The wrapping member is constructed of a plurality of wrapping yarns having flexibility. The plurality of wrapping yarns are wound around the airbag body as folded into a generally rod-like shape over the generally entire length in the wrapping area, along the airbag body's axial direction, and in a manner to obliquely intersect the axial direction. At least two of the wrapping yarns are wound around the folded airbag body in the wrapping area from the opposite directions. The distance between the adjacent yarns along the axial direction of the folded airbag body, with respect to the wrapping yarns wound in the same direction in the wrapping area, is within the range of 20 to 60 mm, when the wrapping yarns are wound around the folded airbag body. The yarn strength of these wrapping yarns according to JIS L 1013.7.5 is within the range of 7.4 to 65N.
In the first airbag according to the present invention, a plurality of wrapping yarns constituting the wrapping member are not arranged intermittently, but wound around the folded and rod-shaped airbag body along the axial direction of the airbag body, and in a manner to intersect the axial direction of the airbag body obliquely, in the wrapping area of the airbag body. Moreover, at least two of the wrapping yarns are wound around the folded airbag body from the opposite directions.
In the first airbag according to the present invention, accordingly, most part of the outer circumference around the airbag body is held by the wrapping yarns at more than one positions in the wrapping area. As a result, the compactly folded state of the airbag body is uniformly kept along the axial direction of the airbag body. More specifically, even with only two wrapping yarns, those yarns are wound around the folded airbag body in the opposite directions. In this case, two yarns hold the outer circumference around the airbag body only at one position by their intersection. However, in the portion between the intersections apart from the intersection, two yarns are separated from each other to hold the outer circumference of the airbag body. Therefore, the airbag body is wrapped compactly.
Moreover, the wrapping work can be made easily by winding a plurality of wrapping yarns generally helically around the airbag body so as to intersect the axial direction of the airbag body obliquely.
Especially in the present invention, a plurality of wrapping yarns are wound around the folded airbag body, while the distance between the adjacent yarns along the axial direction of the folded airbag body is within the range of 20 to 60 mm, with respect to the wrapping yarns wound in the same direction. Moreover, the yarn strength of the wrapping yarns according to JIS L 1013.7.5 is within the range of 7.4 to 65N. Therefore, the airbag body is wrapped compactly without degrading the expanding property of the airbag.
More specifically, if the distance between the adjacent yarns is less than 20 mm, the density of the wrapping yarns per unit length along the axial direction of the airbag body becomes high. Then the resistance in breaking the wrapping yarns becomes big when the airbag body breaks the individual wrapping yarns to expand and inflate, which is likely to delay the expansion of the airbag. On the contrary, if the distance between the adjacent yarns is more than 60 mm, the area of the airbag body not held by the yarns enlarges in the axial direction of the airbag body, and therefore, the area is likely to bulge, which checks the effect of the present invention of wrapping the airbag body compactly.
Therefore, it is desired that the distance between the adjacent yarns along the axial direction of the folded airbag body, with respect to the wrapping yarns wound in the same direction, be set within the range of 20 to 60 mm.
Moreover, if the yarn strength of each wrapping yarn according to JIS L 1013.7.5 is less than 7.4N, the wrapping yarn is torn when the wrapped airbag body is bent, and fails to wrap the airbag body compactly. On the contrary, if the yarn strength of each wrapping yarn according to JIS L 1013.7.5 is more than 65N, the resistance in breaking the wrapping yarns becomes big when the airbag body breaks the individual wrapping yarns to expand and inflate, which delays the expansion of the airbag.
From the above-described viewpoints, it is desired that the yarn strength of the wrapping yarns according to JIS L 1
Ikeda Takanobu
Kato Katsuhiko
Okajima Shoji
Sugaya Mitsuru
Yamamoto Takashi
Dickson Paul N.
Posz & Bethards, PLC
To Toan
Toyoda Gosei Co,., Ltd.
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