Patent ID: 7150227

Claim:
A multi-stage ignition type gas generator, comprising: a housing having a gas discharge port; a first combustion chamber provided inside the housing; a second combustion chamber provided inside the housing separately from the first combustion chamber; a third combustion chamber provided inside the housing and through which a gas generated in at least one of the first combustion chamber and the second combustion chamber passes before reaching the gas discharge port; a first partition wall separating the first combustion chamber and the third combustion chamber and defining a first communicating port that communicates the first combustion chamber and the third combustion chamber; a second partition wall separating the second combustion chamber and the third combustion chamber and defining a second communicating port that communicates the second combustion chamber and the third combustion chamber; first restriction means that seals the first communicating port, the first restricting means allowing communication between the first combustion chamber and the third combustion chamber only by a gas pressure generated in the first combustion chamber; second restriction means that seals the second communicating port, the second restriction means allowing communication between the second combustion chamber and the third combustion chamber only by a gas pressure generated in the second combustion chamber; a first gas generating agent accommodated in the first combustion chamber for generating a first combustion gas for inflating an air bag; a second gas generating agent accommodated in the second combustion chamber for generating a second combustion gas for inflating the air bag; a third gas generating agent accommodated in the third combustion chamber for generating a third combustion gas for inflating the air bag; a first ignition means for directly igniting and burning the first gas generating agent; a second ignition means for directly igniting and burning the second gas generating agent; and shielding means, which prevents at least one of the first communication port and the second communication port from being obstructed by at least one of the first gas generating agent, the second gas generating agent, and the third gas generating agent, wherein, the first gas generating agent and the second gas generating agent are different in at least one of combustion heat, combustion temperature, all gas output, and gas output per unit time in combustion of the gas generating agent.