Inflator for air bag

Claim 1

An inflator for an air bag which comprises: a pressure vessel including an upper vessel body formed by a mirror plate and a cylindrical section extending downward from the peripheral edge of said mirror plate, a lower vessel body formed by a mirror plate and a cylindrical section extending upward from the peripheral edge of said mirror plate, the ends of said cylindrical sections of said upper and lower vessel bodies being welded to each other, and an essentially cylindrical partitioning wall provided within said pressure vessel for defining a gas generating chamber wherein high pressure gas is generated to inflate said air bag, a plurality of gas discharge paths defined through said partitioning wall for allowing a flow of generated gas, and at least one through opening defined in one of said upper and lower vessel bodies for externally discharging the gas flowing through said gas discharge paths, wherein said partitioning wall is formed by an upper partitioning wall having a proximal end tightly fitted to said mirror plate of said upper vessel body and a lower partitioning wall having a proximal end tightly fitted to said mirror plate of said lower vessel body, and said upper and lower partitioning walls each having a distal end, one of said distal ends being formed with a diameter slightly larger than the diameter of the other distal end such that the upper and lower partitioning walls mate with one another at said distal ends and slidably move relative to one another upon being subjected to the pressure created by generation of said high pressure gas, said mating distal ends not being physically connected to one another and having a clearance therebetween to facilitate said sliding movement.