All-pyrotechnic inflator

Claim 1

An all-pyrotechnic inflator for generating an inflating gas comprising: an elongated enclosure means having an inner wall, an outer wall, an annular space between said walls, a longitudinal axis and an outlet means in said outer wall for passage of said gas; a linear ignitor arranged within said enclosure means and extending along substantially the entire length of said longitudinal axis of said enclosure means; a pyrotechnic material disposed within said enclosure means and extending substantially around said linear ignitor for combustion and generation of said gas upon ignition by said ignitor, said pyrotechnic material being the sole source of said inflating gas; a nozzle means arranged in said inner wall for passage of said gas to said annular space, said gas passing through said outer wall and said outlet means, said nozzle means comprising a plurality of apertures along at least a part of the longitudinal extent of said inner wall; and means for maintaining substantially constant pressure during generation of said gas, said substantially constant pressure means comprising a plurality of burst plates, one burst plate adjacent to each aperture in said inner wall, each burst plate having an area larger than the area of said adjacent aperture, each burst plate disposed inside of said inner wall and covering said adjacent aperture prior to ignition of said pyrotechnic material, said burst plates being designed so as to burst at different pressures.