Dual stage pyrotechnic inflator

• US 6,983,956 B2
• Filed: 08/14/2003
• Issued: 01/10/2006
• Est. Priority Date: 08/14/2003
• Status: Expired due to Term

• Current Assignee: Key Safety Systems, Inc. (Ningbo Junsheng Investment Group Co., Ltd.)
• Original Assignee: Key Safety Systems, Inc. (Ningbo Junsheng Investment Group Co., Ltd.)
• Inventors: Lam, Keith, Canterberry, J B
• Primary Examiner(s): Fleming, Faye M.
• Application Number:
  US10/640,031
• Publication Number:
  US 20050035579A1
• Time in Patent Office: 880 Days
• Field of Search: 280/736, 280/741, 280/740
• US Class Current: 280/741
• CPC Class Codes: B60R 2021/2633 with a plurality of inflation levels
• CPC Class Codes: B60R 2021/2648 comprising a plurality of combustion chambers or sub-chambers
• CPC Class Codes: B60R 21/2644 using only solid reacting substances, e.g. pellets, powder

Abstract

The inflator has a first combustion chamber and a second combustion chamber. Gas generant contained in the first combustion chamber is independently ignited from gas generant contained in the second combustion chamber. A divider plate extends across the entire inflator dividing the inflator into a first combustion chamber and a second combustion chamber. The divider plate has a generally flat shape associated therewith. A first igniter of the inflator ignites the gas generant in the first combustion chamber, and the inflation gas from the burning of this gas generant passes through only a first filter and then exits the inflator via first exit ports. A second igniter of the inflator ignites the gas generant in the second combustion chamber. The burning of gas generant in the second combustion chamber produces inflation gas which travels through only the second filter and then through second exit ports. The first igniter and the second igniter are disposed on the same end of the inflator.

Claims

1. An inflator comprising:

a first igniter for igniting a gas generant disposed in a first combustion chamber;

a second igniter for igniting a gas generant disposed in a second combustion chamber;

a divider plate for dividing the inflator into the first combustion chamber and the second combustion chamber, the divider plate has an opening therethrough located off center axis, the divider plate has a generally flat shape therewith, wherein the divider plate prevents sympathetic ignition of the gas generant, the divider plate having a cylindrical protrusion extending in the direction of the upper housing whereby the cylindrical protrusion engages with the enhancer tube; and

a single enhancer tube extending from the first combustion chamber to the second combustion chamber through the opening of the divider plate, wherein the lower housing has a plurality of second exit ports arranged around the circumference thereof, the upper housing has a plurality of first exit ports arranged around the circumference thereof, an inflation gas produced by the burning of the gas generant in the first combustion chamber flows out of the inflator via the first exit ports, and an inflation gas produced by the burning of the gas generant in the second combustion chamber flows out of the inflator via the second exit ports.

2. The inflator according to claim 1 further comprising a lower housing and an upper housing whereby the lower housing is securely attached to the upper housing, the divider plate radially interfaces with an inner surface of the joint around the entire inflator.

3. The inflator according to claim 1 wherein the divider plate is situated between the first exit ports and the second exit ports.

4. The inflator according to claim 1 wherein the enhancer tube has an annular flange contacting a surface of the divider plate facing the upper housing.

5. The inflator according to claim 1 further comprising an enhancer donut press fit against the metal cup of the second igniter.

6. The inflator according to claim 5 wherein the divider plate has a recess for partially receiving the enhancer donut, the recess is situated off center axis.

7. The inflator according to claim 1 further comprising a first filter for trapping solid particles produced from the combustion of the gas generant in the first combustion chamber, the first filter has an enlarged portion on a peripheral end opposite the divider plate.

8. The inflator according to claim 1 further comprising a second filter for trapping solid particles produced from the combustion of the gas generant in the second combustion chamber, the second filter has an enlarged portion on a longitudinal end distal from the divider plate.

9. The inflator according to claim 1 wherein the enhancer tube has a plurality of enhancer tube holes arranged around the circumference thereof, the enhancer tube holes provide a passageway between the first combustion chamber and an interior volume of the enhancer tube.

10. An inflator comprising:

an lower housing having a plurality of second exit ports arranged around the circumference thereof;

a upper housing having a plurality of first exit ports arranged around the circumference thereof;

a divider plate fixedly attached to a circumferential joint between the lower housing and the upper housing, the divider plate is disposed below a plane through the second exit ports, the divider plate is disposed above a plane through the first exit ports, the divider plate having a cylindrical protrusion extending toward the upper housing whereby the cylindrical protrusion engages with the enhancer tube;

a first combustion chamber having gas generant situated above the divider plate; and

a second combustion chamber having gas generant situated below the divider plate, wherein the divider plate prevents sympathetic ignition of the gas generant.

11. The inflator according to claim 10 wherein the divider plate radially interfaces with an inner surface of the circumferential joint around the entire inflator.

12. The inflator according to claim 10 wherein the divider plate has an opening therethrough located off center axis, wherein the divider plate has a generally flat shape therewith.

13. The inflator according to claim 10 wherein the divider plate has a recess for partially receiving an enhancer donut, the recess is situated off center axis.

14. The inflator according to claim 10 further comprising a first filter for trapping solid particles produced from the combustion of the gas generant in the first combustion chamber, the first filter has an enlarged portion on a longitudinal end distal from the divider plate.

15. The inflator according to claim 10 further comprising a second filter for trapping solid particles produced from the combustion of the gas generant in the second combustion chamber, the second filter has an enlarge portion on a peripheral end opposite the divider plate.

16. The inflator according to claim 10 wherein the enhancer tube has a plurality of enhancer tube holes arranged around the circumference thereof, the enhancer tube holes provide a passageway between the first combustion chamber and an interior volume of the enhancer tube.