I. Field of the Invention
The invention relates to an air bag deployment system for side impacts, and more particularly, for a deployment system which is mounted in a seat back.
II. Description of the Related Art
In order to provide passengers of vehicles with protection from side impact, it is known to utilize air bags which are deployed from the vehicle seat backs to extend between a passenger and the vehicle side wall or door. The air bag module is mounted to the frame of the seat within a foam cushion. Upon activation, the air bag ruptures the cushion and a frangible seam line in the trim cover to extend outwardly from the seat back. Various methods have been used to ensure that the bag deploys properly. These include storing the bag within a box which has a frangible end to direct the direction of deployment, such as disclosed in U.S. Pat. No. 5,700,028. However, such an arrangement may alter the ergonomics and comfort of the seat back.
It is also known, as disclosed in Japanese laid-open Publication No. HE18-258660, to direct the deployment of the air bag to a seam in the trim cover between a pair of spaced apart flexible straps. One end of each strap is fixed to the frame and the other end is sewn to one side of the seam line. The straps follow the inside contour of the foam cushions. When the inflator is activated the air bag is inflated and deployed between two straps which direct the bag at the seam. However, the straps follow the contour of the foam so that deployment of the bag pushes outwardly against the foam, thereby producing slack in the straps with a resultant loss of energy.
It is also known to affix a single strap to the frame to extend around the foam cushion and inside of the trim cover to the seam line. The strap encircles a rear portion of the cushion as it travels from the frame to the seam line. When the air bag is deployed, the strap compresses the rear portion of the cushion. A substantial loss of energy arises because of the slack in the strap occurring during the compression of the foam cushion.
Accordingly, it would be desirable to produce a side impact energy management system having a relatively low gas pressure for deployment and is simply and inexpensively installed.
It is an additional object of the invention to present a side impact energy management system which has high repeatability of deployment and maintains the ergonomics of the seat.