Dual stage air bag inflator

An inflator for providing inflation fluid for inflating an inflatable vehicle occupant protection device, the inflator comprising:

• a primary housing having an upper wall and a lower wall opposite the upper wall, the primary housing being constructed from sheet metal by stamping;
• a primary inflation fluid source disposed within the primary housing actuatable to deform the primary housing to move the upper wall and the lower wall away from each other;
• a secondary housing constructed from sheet metal by stamping and including an upper portion and a lower portion, the secondary housing being disposed within the primary housing;
• and
• a secondary inflation fluid source disposed within the secondary housing actuatable to move the upper portion of the secondary housing relative to the lower portion of the secondary housing to release inflation fluid from the secondary housing, wherein the upper portion of the secondary housing abuts the upper wall of the primary housing and the lower portion of the secondary housing abuts the lower wall of the primary housing prior to actuation of the primary inflation fluid source.