Abstract: Apparatus and method are provided for actuating a passenger restraint system in a passenger vehicle. A sensor, such as an accelerometer, provides a vehicle condition signal indicative of a potential deployment condition suitable for actuating the restraint system. A first signal is provided so long as the value of the condition signal exceeds that of a first threshold level. An integrator is operative in response to the first signal for integrating the condition signal and providing an integrated signal. The integrator is normally operative to be reset upon termination of the first signal. A trigger signal is provided for actuating the restraint system when the value of the integrated signal exceeds that of a second threshold level. The integrator is prevented from being reset upon termination of the first signal once the first signal has had a time duration of at least time period T1.

Abstract: Apparatus and method are presented for actuating a passenger restraint system in a passenger vehicle. A sensor senses vehicle deceleration and provides a deceleration signal having a value which varies in accordance therewith. A plurality of crash evaluation circuits each respond to the deceleration signal for evaluating the deceleration signal in accordance with respectively different crash evaluation algorithms. Each evaluation circuit provides a vote signal when its evaluation of the deceleration signal indicates that the restraint system should be actuated. The vote signals are summed to provide a summation signal. The summation signal has a fractional value dependent upon the ratio of the number of vote signals to the total number of evaluation votes. The restraint sytsem is actuated when the summation signal exceeds a threshold level.

Abstract: Apparatus and method are provided for actuating a passenger restraint system in a passenger vehicle. Vehicle deceleration is sensed and a vehicle condition signal is provided which varies in value with that of vehicle deceleration. The condition signal is differentiated to provide a jerk signal having a value which varies with the rate of change of the vehicle deceleration. A predetermined time period is timed only so long as the value of the condition signal exceeds that of a first threshold level. A second signal is provided so long as the value of the jerk signal exceeds that of a jerk threshold level. A trigger signal is provided for actuating the restraint system only when the second signal occurs during the predetermined time period.

Abstract: A gas damped acceleration switch for use as a vehicle crash-sensing device. A mass is supported for movement along an axis against a spring, the mass actuating a switch only after moving a predetermined distance against the spring by an accelerating force. A gas damping system makes the device sensitive to the duration as well as the magnitude of the velocity change. Damping is provided by a plate movable with the mass having surfaces that are perpendicular to the axis of motion. The plate is normally pressed against a mating surface to exclude air. A seal is formed between the mating surfaces around the periphery so that a partial vacuum is formed as the mass moves the surfaces apart. When the surfaces move apart a predetermined distance, the seal is broken and the pressure equalizes. However, the moving plate still produces viscous damping as a function of velocity as it continues to be moved through the air by acceleration of the mass against the spring.

Abstract: A snap-action thermal relay in which a thin sheet of spring material having a central opening is mounted at one point along one edge and is crimped along an adjacent edge to distort the sheet into a slightly convex bowed shape. A heater element in the form of a thin band of metal is anchored at either end to the normally convex surface of the sheet adjacent opposite edges of the sheet, with a bridging member inserted between the band and the sheet to put the band under tension. A printed circuit heating element is applied to the band on the side opposite from the sheet. The tension in the band holds the sheet in a concave bowed condition. Heating of the bank reduces the tension in the band and allows the sheet to snap back to its normal convex bowed condition. This action brings the band into direct thermal contact with the convex surface of the sheet over a substantial length of the band to provide good conductive transfer of heat from the band and heater to the spring sheet.

Abstract: A sensor which utilizes the difference in thermal characteristic between two fluids to detect the presence of one fluid or the other. A continuously heated thermal expansion element activates a switch. When the element is brought in thermally conductive contact with a liquid, the heated element drops in temperature, shortening the length of the expansion element and activating the switch.

Abstract: A solenoid in which the coil is positioned inside a housing of magnetic material. The housing has a tubular projection forming a recess in the inside of the end wall along the axis of the coil, one end of the plunger projecting beyond the coil into the recess when the plunger is in the energized position. The portion of the plunger that extends into the recess is tapered to obtain a constant force-displacement characteristic for the full travel of the plunger.