Passive restraint system for a vehicle occupant using an air bag

A passive restraint system for a vehicle occupant using an air bag that can be inflated upon detection of a deceleration exceeding a certain threshold level, comprising:

• an inflator housing containing an inflator for producing gas for inflating an air bag and having a first opening from which gas produced from said inflator may be expelled;
• an air bag housing attached to said inflator housing, and having a second opening disposed so as to be communicated with said first opening of said inflator housing when said air bag housing is attached to said inflator housing, and a third opening placed opposite to said second opening;
• an air bag received in said air bag housing in a folded state, and adapted to be projected and deployed from said third opening of said air bag housing when said air bag is inflated by said gas, said air bag being provided with an open base end from which gas produced from said inflator may be introduced into said air bag to inflate the same;
• and
• said third opening being placed in an opening provided in a part of a vehicle body part, and closed by a lid member which can rupture when said air bag is deployed, said lid member being engaged by said vehicle body part by first engagement means which guides said lid member into alignment with said opening of said vehicle body part, and by said air bag housing by second engagement means which secures said lid member in said opening of said vehicle body part and resiliently allows a slight lateral movement of said lid member with respect to said vehicle body part.