US Patent 6962366 Air bag device

An air bag is formed by sewing a first basic fabric opposed to an occupant and a second basic fabric on the opposite side, at a sewn portion along an outer peripheries of the fabrics. The air bag is folded in a longitudinally longer shape, and an oblong restricting member is wound around a central portion of the air bag to fix the air bag in a bundling manner, and then the air bag is vertically folded. In the process of expansion of the air bag, the air bag bundled by the restricting member is first expanded vertically and then expanded laterally after breakage of a breaking portion of the restricting member which cannot withstand a tension. Thus, by providing the restricting member, the shape and direction of the air bag can be controlled as desired in the process of deployment.