Patent ID: 7404575

Claim:
An air bag apparatus comprising: a case; and an air bag folded in the case, wherein the air bag includes an outer sheet and an inner sheet, wherein the inner sheet and the outer sheet have substantially the same shape and are seamed to one another; and a front inner sheet and a front outer sheet, which are seamed with edges of the outer sheet and the inner sheet, wherein the air bag, when inflated, includes a through hole, which extends through the air bag such that a gas injected within the air bag flows annularly around the through hole, the air bag includes at least a first expanded portion and a second expanded portion, which are formed between the outer sheet and the inner sheet, and a third expanded portion, which is formed between the front inner sheet and the front outer sheet and at a rear end of the air bag, the gas is injected into the air bag at a front end of the air bag, which is opposite to the rear end of the air bag, when the air bag is inflated, a gas is supplied to the first and second expanded portions so that the first and second expanded portions inflate and oppose one another, and then the gas is supplied to the third expanded portion through the first and second expanded portions, and the air bag is constructed so that a tension of the inner sheet, which forms the through hole, is less than a tension of the outer sheet, such that the through hole is substantially closed when the air bag is inflated.