Dual stage air bag inflator with secondary propellant cap

摘要

An inflator (10) for inflating an inflatable device includes a housing (20). A primary propellant (240) in a primary chamber (200) in the housing (20) is ignitable to provide inflation fluid to inflate the inflatable device. A secondary propellant (250) in a secondary chamber (180) in the housing (20) is ignitable to provide inflation fluid to inflate the inflatable device. The inflator (10) includes initiator means (130, 154) for selectively igniting either the primary propellant (240) alone or both of the primary and secondary propellants (240, 250). The inflator (10) also includes a secondary propellant cap (260) for closing the secondary chamber (180) and for maintaining the secondary propellant (250) in the secondary chamber. The secondary propellant cap (260) has a first position blocking flow of combustion products of the first propellant (240) into the secondary chamber (180) when only the primary propellant is ignited. The secondary propellant cap (260) is movable by combustion products of the secondary propellant (250) when ignited from the first position to a second position enabling flow of inflation fluid out of the secondary chamber (180) to inflate the inflatable device.