Apparatus and method for releasing an inflation gas from an inflator

1. An external containment device for an inflator, the containment device comprising:

an outlet plate having an outlet opening;

a burst disk disposed over the outlet opening;

an initiator having an initiator cap;

a support pin having a shaft portion and a head portion, the shaft portion being supported by the initiator cap and the head portion contacts the burst disk when the outlet opening is sealed by the burst disk;

wherein activation of the initiator causes the initiator cap to move shearing a portion of the shaft portion from the support pin which allows the burst disk to rupture, and wherein the external containment device further comprises a screen portion wherein the shaft portion passes through the screen portion and portions of the burst disk are retained by the screen portion.

2. The external containment device as in claim 1 , wherein the screen portion and the head portion are configured such that the head portion is retained by the screen portion.

3. The external containment device as in claim 2 , wherein the shaft portion has a notch to promote shearing of the shaft portion when the initiator cap moves.

4. The external containment device as in claim 2 , wherein a portion of the shaft portion passes completely the initiator cap and contacts a housing that is secured to the inflator.

5. An external containment device for an inflator, the containment device comprising:

an outlet plate having an outlet opening;

a burst disk disposed over the outlet opening;

an initiator having an initiator cap;

a support pin having a shaft portion and a head portion, the shaft portion being supported by the initiator cap and the head portion contacts the burst disk when the outlet opening is sealed by the burst disk;

wherein activation of the initiator causes the initiator cap to move shearing a portion of the shaft portion from the support pin which allows the burst disk to rupture; and

wherein a portion of the shaft portion is received within the initiator cap.

6. The external containment device as in claim 5 , wherein the shaft portion has a notch to promote shearing of the shaft portion when the initiator cap moves.

7. The external containment device as in claim 5 , further comprising a screen portion wherein the shaft portion passes through the screen portion and portions of the burst disk are retained by the screen portion.

8. The external containment device as in claim 5 , further comprising a screen portion wherein the screen portion and the head portion are configured such that the head portion is retained by the screen portion.

9. The external containment device as in claim 5 , wherein the shaft portion has a notch to promote shearing of the shaft portion when the initiator cap moves and wherein the shaft portion passes through a screen portion and portions of the burst disk are retained by the screen portion and wherein the screen portion and the head portion are configured such that the head portion is retained by the screen portion.

10. The external containment device as in claim 5 , wherein the portion of the shaft portion passes completely through the initiator cap and contacts a housing that is secured to the inflator.

11. An inflation device for inflating an inflatable cushion of an airbag module, the inflation device comprising:

a first chamber and a second chamber, the first chamber having a first volume of inflation gas and the second chamber having a second volume of inflation gas;

a first inflation opening for allowing the first volume of inflation gas to pass therethrough;

a second inflation opening for allowing the second volume of inflation gas to pass into the second chamber;

an external containment device sealing the first inflation opening, the containment device comprising:

an outlet plate having an outlet opening;

a burst disk disposed over the outlet opening;

an initiator having an initiator cap;

a support pin having a shaft portion and a head portion, the shaft portion being supported by the initiator cap and the head portion contacts the burst disk when the outlet opening is sealed by the burst disk;

wherein activation of the initiator causes the initiator cap to move shearing a portion of the shaft portion from the support pin which allows the burst disk to rupture; and

a screen portion wherein the shaft portion passes through the screen portion and portions of the burst disk are retained by the screen portion and wherein the screen portion and the head portion are configured such that the head portion is retained by the screen portion.

12. The inflation device as in claim 11 , wherein the shaft portion has a notch to promote shearing of the shaft portion when the initiator cap moves.

13. The inflation device as in claim 11 , wherein the shaft portion has a notch to promote shearing of the shaft portion when the initiator cap moves.

14. The inflation device as in claim 13 , wherein a portion of the shaft portion passes completely through the initiator cap and contacts a housing that is secured to the inflator.

15. The inflation device as in claim 11 , wherein a portion of the shaft portion passes completely through the initiator cap and contacts a housing that is secured to the inflator.

16. The inflation device as in claim 15 , wherein the shaft portion has a notch to promote shearing of the shaft portion when the initiator cap moves and wherein the shaft portion passes through the screen portion and portions of the burst disk are retained by the screen portion and wherein the screen portion and the head portion are configured such that the head portion is retained by the screen portion.

17. The inflation device as in claim 16 , wherein the first volume of inflation gas is selected from the group comprising helium, argon, carbon dioxide, nitrogen and mixtures thereof and the second volume of inflation gas is selected from the group comprising helium, argon, carbon dioxide, nitrogen and mixtures thereof.

18. A method of rupturing a burst disk of an inflator, the method comprising:

supporting the burst disk with a support pin having a shaft portion and a head portion, the shaft portion being supported by an initiator cap of an initiator and the head portion contacting the burst disk, wherein the burst disk is disposed over an outlet opening and wherein the shaft portion passes through a screen portion disposed between the burst disk and the initiator cap; and

shearing the shaft portion of the pin by moving the initiator cap from a first position to a second position by activating the initiator, wherein the head portion no longer supports the burst disk when the initiator cap is at the second position and the shaft portion is sheared from the support pin.