Abstract: A plurality of pneumatic hydrostatic weight sensors, each incorporating a fluid and a pressure sensor for sensing the pressure thereof, are incorporated in series with the load path within a vehicle seat to sense occupant weight. A signal processor measures the pressure within each pneumatic hydrostatic weight sensor and the weight of the occupant from the signal generated by the associated pressure sensor, and compensates for the effects of ambient pressure or temperature on the weight measurement responsive to the difference in pressure between the associated pressures of two of the pneumatic hydrostatic weight sensors.

Abstract: A hydrostatic weight sensor comprises a continuous flexible sensing tube incorporated within the seat. A fluid is contained therein and a pressure sensor is operatively coupled thereto. The continuous flexible sensing tube may be arranged in a spiral or serpentine pattern, or comprise a plurality of segments each in fluid communication with a central port. A load applied to the seat causes the continuous flexible sensing tube to deform, thereby increasing the pressure of the fluid contained therein. A signal processor calculates the weight of the occupant from the pressure signal, and controls a safety restraint system responsive to the weight measurement.

Abstract: A plurality of ultrasonic transmitters, at distinct locations and with distinct transmitting frequencies, direct beams of ultrasonic sound waves at a one or more detection regions of space. The amplitude of the ultrasonic sound waves is sufficient to generate from each detection region a sound wave having a frequency corresponding to the difference of the frequencies of the respective ultrasonic sound waves. A receiver disposed proximate to the ultrasonic transmitters detects the generated sound wave. An object occupying the detection region blocks one or more of the beams, and is detected therein when the magnitude of the generated sound wave is below a threshold. In another aspect of the instant invention, the ultrasonic transmitters are adapted to transmit pulses forming relatively broad spherical wavefronts which intersect to form a circular detection region which propagate with time, thereby enabling the detection of a profile of an object.

Abstract: A membrane weight sensor incorporates a plurality of membrane switch elements, each characterized by a distinct activation force threshold determined by the effective diameter and activation travel distance of the associated membrane. A plurality of membrane switch elements is incorporated into a single membrane switch pad. The membrane switch pad is aligned with a pair of first and second plates, one of which incorporates a plurality of protrusions, each operatively coupled to a different membrane switch element for purposes of deflecting the associated membrane. The signals from each of the associated switch elements are encoded and combined so as to form a single analog output signal having a plurality of discrete levels indicative of the amount of force applied to the membrane weight sensor.

Abstract: A vehicle seat belt tension measurement apparatus comprises a seat belt deflecting device that forces a seat belt to travel a circuitous path. As seat belt tension increases the deflecting device is displaced. A bend sensor having an output signal responsive to a change in the radius of curvature thereof is secured to the deflecting device at a point subject to flexure as a result of increased seat belt tension. An air bag control system processor operatively coupled to the bend sensor inhibits the deployment of the air bag upon detection of a predetermined seat belt tension.

Abstract: An occupant position sensing system incorporates an electric field sensor (30) into or on the cover (14) of an air bag inflator assembly (12) for purposes of sensing an occupant proximate the air bag inflator so that the air bag inflator may be disabled, or a warning device (26) may be activated, if the occupant is found to be within the associated danger-zone thereof. The electric field sensor (30) may comprise a plurality of electrodes (16), at least one of which is incorporated into or on the cover (14) of the air bag inflator assembly (12), wherein an occupant proximate the sensor electrodes modifies the associated inter-electrode capacitance (50). The output from the electric field sensor (30) may be used to control a controllable air bag inflation system responsive to occupant position.

Abstract: A seat weight sensor incorporates a fluid containing bladder placed in series with the load path in the seat, whereby a load applied to and distributed across the bladder increases the pressure of the fluid therein. The pressure of the fluid is measured by a pressure sensor and is substantially proportional to the magnitude of the applied load, and substantially inversely proportional to the supported area of the bladder. The output signal is substantially linear with respect to weight. Preferably, the amount of fluid in the bladder should be less than the capacity of the bladder when the bladder is unloaded. The seat weight sensor is incorporated into an occupant restraint system for controlling the safety restraint system responsive to the weight of the occupant.