Abstract: A gas generant wafer design having a channel region integrally formed into one or both of its sides or faces. Characteristic of the wafer is that the geometric design of the wafer is improved by increasing its cross-section in the same manner that an "I-Beam" increases the structural characteristic of a linear structural member.

Abstract: A device and method for detecting pressure changes in a pressurized vessel, such as a gas storage bottle of an inflator of a vehicle restraint system. At least two reference marks are positioned on an outside surface of the vessel for indicating the pressure in the vessel. The marks are spaced apart on the surface by a predetermined distance. The predetermined distance can be measured at intervals, and correlated to determine changes in the pressure of the vessel. The references marks can be physical, i.e., paint or scratch marks, or magnetic, such as a magnetic bar or stripe. The physical marks can be read by an optical laser and the magnetic marks by a magnetic head, such as a floppy or hard disk drive, or a CD-ROM.

Abstract: Featured for use as a part of an inflator-containing inflatable restraint system is a multipiece reaction canister wherein pieces of the canister are normally secured together by thermally degradable joining members which degrade at a temperature greater than the ambient temperature to which the reaction canister is normally subjected and less than the temperature at which the inflator autoignites, to permit separation of the reaction canister pieces and provide venting of pressure that can build-up within the reaction canister. As a result of alleviating concerns such as of material fragmentation when exposed to extreme heat conditions, e.g., a fire, the invention allows the more widespread use of light weight, temperature sensitive materials in reaction canister constructions.

Abstract: A low pressure sensing device for sensing pressure changes in a pressurized gas storage bottle of an inflater. At least one wire is wrapped around the vessel to sense the expansion or contraction of the vessel due to pressure changes in the vessel. The wire has a first end and a second end. The first end of the wire is secured to the vessel and the remainder of the wire is free to move circumferentially relative to the vessel in response to the expansion and contraction of the vessel. This relative movement can be monitored to determine if a pressure change has occurred in the vessel.

Abstract: A membrane seal assembly separating forward and aft combustion chambers of a rocket motor. The assembly covers the aft surface of a bulkhead having apertures therein to preclude flow communication between the combustion chambers during combustion of propellant within the aft combustion chamber. The assembly includes a membrane which has a plurality of sectors which open along hinge lines away from the bulkhead to allow flow communication between the combustion chambers when a higher pressure is present in the forward combustion chamber than in the aft combustion chamber, i.e., during subsequent combustion of the propellant in the forward combustion chamber.

Abstract: A multi-stage air bag inflator includes a housing with at least two separated chambers, each containing gas generating material and an ignition system for activating the material to generate gas for rapidly filling an associated air bag. An internal wall is provided in the housing to form the separated chambers and the wall has a frangible section designed to rupture in response to a predetermined level of gas pressure in one of the chambers providing fluid communication between the chambers. The frangible section is supported against rupture in response to gas pressure in the other gas chamber so that different levels of air bag inflation with gas are possible in response to the severity of the impact.

Abstract: A tethered knee bolster panel which is deployed rearward in the passenger compartment of an automotive vehicle during a crash to provide lower torso restraint. The knee bolster is an air bag system which propels the knee bolster panel rearward during deployment. The activated knee bolster allows automobile designers the flexibility to provide increased leg room in the vehicle while maintaining the same level of safety during a crash.

Abstract: An inflatable vehicle occupant restraint having a dynamic burn vent wherethrough inflation gas can be appropriately vented therefrom. Such an inflatable vehicle occupant restraint has particular application for side impact restraint systems wherein increased venting by the dynamic vents occurs subsequent to full deployment of the inflatable restraint.

Abstract: A single device acts as a pressure switch, gas generated heater, and an igniter. The device has pyrotechnic material such as a combustible gas in an inner chamber. An outer chamber, that is, a chamber in which the device is positioned, includes a gas that may or may not be combustible. A monitor current flows through a pressure monitor resistor and a bridgewire resistor monitoring continuity. When the pressure in the outer chamber decreases below a threshold value, the pressure monitor resistor breaks continuity and causes a resistance change. If an air bag is to deploy, the bridgewire resistor heats up to a point that the pyrotechnic material in the inner chamber is ignited. The resulting combustion ruptures pressure discs and the outward hot product heats the gas in the outer chamber. The outer chamber ruptures and the heated gas therein flows in the air bag.

Abstract: Two electrically conductive diaphragms which are disposed in generally parallel relation and are symmetrical mirror images of each other are joined to a non-conductive ring. The diaphragms are joined in a pressurized atmosphere of argon at, for example, 3000 psi. When so pressurized internally and with lower external pressure, the diaphragms do not contact each other. When pressurized externally to a pressure to a predetermined level higher than the internal pressure, the diaphragms make contact with each other to close an electric circuit. If pressure leaks into the switch or the external pressure drops, the diaphragms separate and break contact with each other.

Abstract: An air bag inflator responds to signals from a diagnostic unit to terminate filling of the bag prior to full inflation. This is accomplished by a piston propelled by a secondary charge which is ignited by a second signal from the diagnostic unit. The piston blocks the air bag inflation passages and simultaneously opens vents to discharge the remaining inflation gas.