Abstract: A hybrid inflator having a quantity of stored gas in a pressure vessel, and a quantity of gas generant stored within a generant housing having at least one port in its longitudinal end. Within the generant housing the gas generant is retained within a porous sleeve. This sleeve is spaced inward from the non-porous generant housing, such that a free flow area is formed between the sleeve and the generant housing. The inflation gas created by the gas generant will thus flow radially outward through the sleeve, and then be turned to flow longitudinally toward the port(s) in the generant housing. Providing the free flow area reduces the pressure drop across the generant sleeve, resulting in less slag being forced through the sleeve to be entrained within the created gas flow. Additionally, the changes in direction forced upon the created gas flow to exit the generant housing cause additional amounts of slag to be removed from the created gas flow. This results in a hybrid inflator having reduced solid emissions.

Abstract: A sequencing system is provided for varying the output of an inflator in a vehicle safety restraint system. The inflator has a housing including at least one combustion chamber. Gas generant for producing an inflation gas is disposed in the housing. Ignition material for igniting the gas generating means is disposed in the at least one combustion chamber. A first electric squib is disposed in the inflator housing for initially igniting the ignition material. At least one additional electric squib is disposed in the inflator housing for further igniting the ignition material. A delay sequencing unit is disposed outside of the inflator housing for activating the at least one additional electric squib after a predetermined time from the activation of the first electric squib. Upon activation of the first electric squib by an electrical pulse, an initial amount of inflation gas is generated and the electrical pulse is also received by the delay sequencing unit.

Abstract: An inflator for an airbag system has a target mounted in the pressurized gas contained in the inflator. An ultrasonic transducer is mounted on an external surface of the inflator in alignment with the target. The transducer generates and receives reflected ultrasonic signals from the target. The time-of-flight of the signals which are dependent on the gas pressure are used to determine the gas pressure in the inflator. Temperature compensation is provided by fabricating the target of bimetallic material which changes the spacing of the target from the transducer with temperature or providing a temperature sensitive element, e.g. a thermocouple to electrically provide temperature compensation.

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 horn switch assembly including an airbag module cover, a bend sensor and a backing plate. The module cover has a front outer face and a rear inner face deformably depressible from the front face. A plurality of parallel, spaced-apart, elongated force concentration ribs are located on the rear inner face of the cover. The bend sensor is positioned under the force concentrators and includes a flexible substrate and a variable resistance circuit connectable to a horn control circuit. The variable resistance circuit has a plurality of spaced-apart resistive elements connected by a plurality of conductive strips. The variable resistance circuit is arranged in a plural of parallel spaced-apart columns adhered to the substrate so that the columns are generally perpendicular to the force concentration ribs and each resistive element is positioned under a force concentration rib. The generally rigid backing plate has a forward surface positioned under the bend sensor.

Abstract: A temperature compensating low pressure sensor for verifying loss of gas from an inflator of a vehicle restraint safety system. The sensor includes a housing and a pressure diaphragm in communication with the fluid in the inflator. A temperature sensitive bimetallic thermostat is disposed within the housing. The thermostat expands with relation to a change in temperature of the fluid at the same rate as the pressure diaphragm. A retainer in communication with the pressure diaphragm is movably disposed in the housing. A stack of spring washers is disposed between the retainer and the thermostat for counteracting the pressure of the fluid acting upon the diaphragm. A contact arm in contact with the thermostat moves with the retainer.

Abstract: Featured for use with a hybrid air bag inflator containing inert stored gas under high pressure is a liquid fueled construction which combines the functions of an initiator, gas generator, and differential low pressure switch into a single device. Instead of being filled with a mixture of combustible gases, the device is filled with a combination of gases and liquids. Alternatively, it makes use of a hybrid squib in conjunction with different combinations of gases and liquids. A pyrotechnic material is used to ignite the mixture regardless of the combination of fuel and oxidant used in the device. A ceramic body is used to house the device. Upon combustion of the mixture, the ceramic body ruptures violently, permitting efficient transfer of the explosive energy to the inert stored gas in the hybrid inflator.

Abstract: A pressure activated switch is positioned for actuation of a horn in the steering wheel of a motor vehicle. The switch is mounted on an airbag cover and generates a signal when the switch is activated by the deflection of the cover. A temperature sensing device is positioned on the cover for generating a signal indicative of the cover temperature. The temperature signal is utilized for changing the actuation pressure or deflection required on the pressure or deflection activated switch to compensate for changes in cover stiffness due to the temperature changes of the cover. The invention is thus directed to providing a consistent horn actuation force regardless of the temperature of the airbag cover to which such force is applied to actuate the horn of the motor vehicle.

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: A method and apparatus especially useful for supplying inert gas to a highly pressurized pressure vessel, such as a hybrid inflator for an automotive airbag module, and weld sealing the gas passage or opening therein to avoid or substantially eliminate weld cracks. The apparatus for accomplishing same comprises no moving parts and the welding is accomplished by utilizing a groove feature formed into the surface of the pressure vessel wall surrounding the gas passage or opening so that no additional filler material is required to obtain the weld seal. The method and apparatus may also be used to weld seal low or non-pressurized vessels as well as vacuum vessels.