Two-stage automotive gas bag inflator using igniter material to delay second stage ignition
First Claim
1. An inflator comprising:
- an elongated housing,a bulkhead located in said housing at an intermediate position along the length thereof, said bulkhead having a perforation therein,a pyrotechnic gas generator contained within said housing comprised of first and second gas generating charges extending in end-to-end relation therein with one of said charges being located on one side of said bulkhead and the other charge being located on the other side thereof, andinitiator means in said housing comprising first and second igniter tubes associated, respectively, with said first and second gas generating charges for effecting ignition thereof, each of said igniter tubes having a common longitudinal axis and containing igniter material therein with the igniter material contained in said second igniter tube being characterized to burn at a rate different from the igniter material in the first igniting tube, and an elongated fuse extending through the perforation in said bulkhead and said igniter tubes and positioned substantially coincident with the common longitudinal axis thereof, and a single squib positioned adjacent a portion of said fuse, and operative when fired, to initiate activation of said fuse thereby to effect substantially simultaneous ignition of the igniter material contained in each of said first and second igniter tubes.
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Accused Products
Abstract
A dual-stage gas bag inflator, operable initially, when activated, to cause the gas bag to deploy slowly and then, after a delay, to deploy rapidly, includes a housing having first and second compartments of different size separated by a bulkhead. The first compartment is the smaller since it is to produce a smaller amount of gas to cause the initial slow deployment of the gas bag. A gas generant charge is ignited in the first compartment, and after some delay, a gas generant charge in the second compartment is ignited. The delay is produced by an initiator including a squib, igniter material in each of the first and second compartments, and a fuse cord which is ignited by the squib. The fuse cord passes through the bulkhead and ignites all igniter materials in both inflator compartments simultaneously. The igniter material in the second compartment is so characterized that it burns slower than the igniter material in the first compartment. When ignited, the igniter material in the first compartment burns outwardly rapidly while that in the second compartment burns outwardly relatively slower. As a result, the gas generant in the first compartment is ignited before the gas generant in the second compartment. The burn rate of the igniter material in the second compartment may be made slower than that in the first compartment by using igniter materials of different chemical composition or by increasing the size of the igniter material, giving it a greater burn area, thus causing it to be consumed slower.
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Citations
20 Claims
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1. An inflator comprising:
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an elongated housing, a bulkhead located in said housing at an intermediate position along the length thereof, said bulkhead having a perforation therein, a pyrotechnic gas generator contained within said housing comprised of first and second gas generating charges extending in end-to-end relation therein with one of said charges being located on one side of said bulkhead and the other charge being located on the other side thereof, and initiator means in said housing comprising first and second igniter tubes associated, respectively, with said first and second gas generating charges for effecting ignition thereof, each of said igniter tubes having a common longitudinal axis and containing igniter material therein with the igniter material contained in said second igniter tube being characterized to burn at a rate different from the igniter material in the first igniting tube, and an elongated fuse extending through the perforation in said bulkhead and said igniter tubes and positioned substantially coincident with the common longitudinal axis thereof, and a single squib positioned adjacent a portion of said fuse, and operative when fired, to initiate activation of said fuse thereby to effect substantially simultaneous ignition of the igniter material contained in each of said first and second igniter tubes. - View Dependent Claims (2, 3, 4, 5, 6, 7, 20)
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8. A two-stage gas generator for inflating a vehicle inflatable restraint cushion comprising:
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an elongated housing including a tubular portion with at least one bulkhead in said tubular portion to provide first and second gas generating compartments therein, said bulkhead having a perforation therein, first and second end portions on said tubular portion, said first end portion being open and said second end portion being closed and formed integrally with said tubular portion, closing means for closing said first end portion of said tubular portion, first and second gas generating means in said first and second gas generating compartments, respectively, and initiator means in said housing comprising first and second igniter tubes associated, respectively, with said first and second gas generating charges for effecting ignition thereof, each of said igniter tubes having a common longitudinal axis and containing igniter material therein with the igniter material contained in said second igniter tube being characterized to burn at a rate different from the igniter material in the first igniter tube, and an elongated fuse extending through the perforation in said bulkhead and said igniter tubes and positioned substantially coincident with the common longitudinal axis thereof, and a single squib positioned adjacent a portion of said fuse, and operative when fired, to effect substantially simultaneous ignition of the igniter material contained in each of said first and second igniter tubes, said tubular portion including aperture means for directing generated gas from each of said first and second compartments to a vehicle inflatable restraint cushion. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. An initiator for the gas generating means in a two-stage inflator comprising:
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a first igniter tube, a second igniter tube, said first and second igniter tubes having a common longitudinal axis and containing igniter material therein, with the igniter material in said second igniter tube being characterized to burn at a rate different than the igniter material in the first igniter tube, said igniter tubes being separated by a bulkhead having a perforation therein and positioned transversely of the common longitudinal axis thereof, said igniter tubes each having a side wall with at least one outlet port therethrough in communication with the igniter material therein, pressure sensitive rupturable cover means for the outlet port in each of said igniter tubes, an elongated fuse extending through the perforation in the bulkhead and through said igniter tubes and located substantially coincident with the common longitudinal axis thereof, and a single squib positioned adjacent a portion of said fuse to initiate activation thereof. - View Dependent Claims (16, 17, 18, 19)
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Specification