US Patent 9469268 Air-bag device

An air-bag device includes an air bag stored in an inner side of a backrest in a vehicle width direction, and an inflator that inflates and expands the air bag. The air bag includes a first chamber that houses the inflator such that the longitudinal direction of the inflator matches the vertical direction of the air bag, and a second chamber that is located above the first chamber and is inflated and expanded by a gas ejected from an upper end of the inflator to form a tubular shape extending upward above the first chamber.