Inflator assembly

An inflator assembly for inflating an inflatable vehicle occupant restraint, said inflator assembly comprising:

• a source of inflation fluid for inflating the vehicle occupant restraint;
• means for directing inflation fluid into the vehicle occupant restraint;
• a closure located to block inflation fluid flow through said directing means, said closure including a predefined break away portion which, when broken away, enables inflation fluid flow through said directing means;
• a projectile member for breaking away said break away portion of said closure to enable inflation fluid flow through said directing means;
• and
• means for propelling said projectile member from a first position in which said closure is located to block inflation fluid flow through said directing means to a second position in which said break away portion of said closure is broken away to enable inflation fluid flow through said directing means;
• said projectile member comprising (i) a mass having kinetic energy when said projectile member is propelled, (ii) a tip for penetrating said break away portion of said closure, and (iii ) surface means for engaging the material of said break away portion of said closure as said tip penetrates said break away portion to enable the kinetic energy associated with said mass to break away said break away portion and then to carry away said break away portion, thereby to enable inflation fluid flow through said directing means.