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A metal bridge initiator, with or without a spark gap feature, for firing an air bag inflator is deposited on a thin plastic film substrate. The bridge can be tuned by adjusting the width and thickness of the substrate. The bridge is of compact size enabling an increase in the strength of the inflat

A metal bridge initiator, with or without a spark gap feature, for firing an air bag inflator is deposited on a thin plastic film substrate. The bridge can be tuned by adjusting the width and thickness of the substrate. The bridge is of compact size enabling an increase in the strength of the inflator in the initiator area thereof. If there is an initiator structural failure, the very small feed through slot into the interior of the inflator will plug up with the products of combustion of the inflator. The intimate contact between the deposited metal bridge and plastic substrate makes the initiator resistant to vibration, bending and damage. The method of manufacturing is simpler than for conventional inflator initiators and is adapted to mass production.

대표청구항 ▼

A printed circuit bridge initiator for an air bag inflator comprising, an elongated thin film electrically nonconducting plastic substrate, said substrate having a thickness, a width and a length, and a printed circuit bridge formed on said substrate comprising spaced electrically conducting strips

A printed circuit bridge initiator for an air bag inflator comprising, an elongated thin film electrically nonconducting plastic substrate, said substrate having a thickness, a width and a length, and a printed circuit bridge formed on said substrate comprising spaced electrically conducting strips extending for substantially the full length of the substrate, said strips being adapted for the connection thereto at one end thereof of a source of direct electrical current and having a bridge connected therebetween at the other end thereof, said bridge being printed on said substrate, wherein said substrate is formed of a polyamide, wherein said spaced electrically conducting strips are formed of metal, wherein tuning of said initiator, that is adjustment of the relationship between the magnitude of the direct electrical current flow through said initiator and the duration of such current flow required to activate said initiator, is effected by adjustment of the width and/or thickness of said substrate and the shape of said bridge, wherein the thickness of said substrate on which said printed circuit bridge .is printed is in the range of 0.002 to 0.02 inches, the width of said substrate is about 0.110 inches, and the length of said substrate is about one inch, and wherein said bridge has the shape of two generally equilateral squares that are positioned in contiguous relation with a corner portion of one square touching a corner portion of the other square, thereby forming a necked down or narrowed portion between them. An inflator for an air bag comprising a housing having a base component with a slot formed therein into the interior of said inflator, said slot having a wall, and including, a printed circuit bridge initiator for said inflator, a portion at least of said initiator being located in the interior of said inflator through said slot and comprising, an elongated thin film electrically nonconducting plastic substrate, said substrate having a thickness, a width and a length, and a printed circuit bridge formed on said substrate comprising spaced electrically conducting strips extending for substantially the full length of the substrate, said strips being adapted for the connection thereto at a first end thereof of a source of direct electrical current and having a bridge connected therebetween at a second end thereof, said bridge being printed on said substrate and forming part of the portion of said printed circuit bridge that is located in the interior of said inflator through said slot, wherein tuning of said initiator, that is, adjustment of the relationship between the magnitude of the direct electrical current flow through the initiator and the duration of such current flow required to activate said initiator, is effected by adjustment of the width and/or thickness of said substrate and the shape of said bridge, wherein said substrate is formed of a polyamide, wherein the thickness of said substrate is in the range of 0.002 to 0.02 inches, the width of said substrate is about 0.110 inch, and the length of said substrate is about one inch, wherein said bridge has the shape of two generally equilateral squares that are positioned in contiguous relation with a corner portion of one square touching a corner portion of the other square, thereby providing a necked down or narrowed portion between them, and wherein said spaced electrically conducting strips are formed of metal.