Airbag and a deployment sensor

摘要

A cartridge stores a quantity of string, one end of which is attached to the inside surface of an airbag cushion. A spool which transitions to a cone is situated within the cartridge. A narrow gap around the spool forms a string storage space and a similar gap overlies the cone and leads to an outlet. Positioned within the body of the cartridge is a light source and a light detector. As string is drawn out of the cartridge, the string traverses between the light sources and a light detector generating a signal directly proportional to the rate at which string is withdrawn. The geometry of the cartridge is arranged to provide friction against the string. The friction is created between the string and the junction between the cylindrical spool and the cone and rapidly overcomes the momentum of the string when the airbag cushion comes to a stop.