This application is related to Japanese Patent Application No. H11-295748, filed Oct. 18, 1999, the disclosure of which is incorporated by reference herein in its entirety.
1. Field of Invention
The present invention relates to head protective bags for vehicle passengers, and, more particularly, to bags inflated along a side window or the like when a side of the vehicle is crashed or the vehicle is rolled over. More specifically, the present invention relates to head protective bags for vehicle passengers that are inflated by gas. Further, the present invention relates to head protective devices for vehicle passengers having the head protective bags and vehicles having the protective devices.
2. Description of the Related Art
This type of head protective bag for vehicle passengers is described in WO 96/26087 and is illustrated specifically in FIGS. 1 and 9 of that publication. This known bag includes a duct portion (main airway) extending along an upper edge of the bag from an end (a front end) of the bag near the vehicle""s front end to an end (a rear end) of the bag near the vehicle""s rear end and a number of cell portions (small cells) connected to the duct portion are extending downward. The head protective bag described in WO 96/26087 will now be described with reference to FIG. 6 of this application.
This head protective air bag device 100 has main components including an elongated duct 106, an air bag body 112, an inflator 116, and a belt-like strap 118. The duct 106 extends along a front pillar portion 102 and a roof side rail portion 104. The air bag body 112 is accommodated in the duct 106 in a folded state and is secured to a vehicle body at a front securing point 108 and a rear securing point 110. The inflator 116 is connected to a rear end of the duct 106 through a hose 114 and generates gas when a predetermined load acts on a side of the vehicle body. One end of the strap 118 is secured to the vehicle body, and the other end of the strap 118 is secured to a rear end of the air bag body 112. The air bag body 112 is formed by connecting a plurality of cells 120. Each cell 120 is substantially cylindrical and is located such that a longitudinal direction of the cell 120 corresponds to a substantial upward or downward direction of the vehicle.
In this structure, the inflator 116 generates gas when a predetermined load acts on a side of the vehicle. The generated gas is sent to each cell 120 of the folded, air bag body 112 through the hose 114 and the duct 106. Accordingly, the cell 120 is inflated in a substantially cylindrical shape such that its longitudinal direction corresponds to the vehicle s upward or downward direction. The air bag body 112 is thus inflated along a window 122 in a curtain-like shape. Further, since the rear end of the air bag body 112 is connected to the vehicle body through the strap 118, the rear end of the air bag body 112 is reliably located in an upper section of a center pillar portion 124.
It is an objective of the present invention to provide a head protective bag for vehicle passengers, a lower section of which is tightly expanded when the bag is inflated, and a protective device and a vehicle having this protective bag.
A head protective bag for vehicle passengers of the present invention is located near a corner defined by a ceiling and a side wall of a passenger compartment and is inflated downward along the side wall by means of gas introduced from a gas inlet. The bag includes a front coupling portion secured to a first pillar near a front side of a vehicle and a rear coupling portion secured to a second pillar located rearward from the first pillar. The bag is characterized in that a dimension L between a lowermost front coupling portion and a lowermost rear coupling portion when the bag is maximally inflated (without being installed in the vehicle) is smaller than a distance S from a position at which the front coupling portion is secured to the first pillar to a position at which the rear coupling portion is secured to the second pillar.
When the head protective bag for vehicle passengers is maximally inflated without being installed in the vehicle, the dimension L between the front coupling portion and the rear coupling portion is smaller than the distance S. Accordingly, when the bag is inflated as installed in the vehicle, an increased tensile force is produced between the front coupling portion and the rear coupling portion of the bag. The portion of the bag between these coupling portions is thus tightly expanded. As a result, the tightly inflated bag receives a passenger who hits the bag.
To reduce the dimension L with respect to the distance S, it is preferred that a plurality of small cells are arranged in a forward or rearward direction in the bag and that a width of a lower section of the bag in the forward or rearward direction is larger than a width of an upper section of the bag in the forward or rearward direction. Further, to reduce the dimension L with respect to the distance S, the bag may include a cabin side sheet and a window side sheet. A cell in which the gas is introduced is formed between the sheets. A coupling portion is provided in the cell for coupling the sheets together. The number of the coupling portions in an upper section of the cell is larger than the number of the coupling portions in a lower section of the cell.
In the present invention, a single inflatable cell may be formed between the sheets.