Apparatus for sensing occupant weight in an actuatable restraint system
AssigneeTRW Inc.
InventorWilliam M. Jarocha
Life of this patent
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Abstract
An apparatus (10) for sensing weight of an occupant on a vehicle seat (36) in an occupant restraint system (10) includes variable inductance sensor (50) mounted in the seat (36) so that inductance of the sensor (50) is functionally related to the occupant's weight on the seat (36). A capacitor (98) is connected in parallel across the variable inductance sensor (50). The capacitor (98) and the variable inductance sensor (50) form a tank circuit (100). An oscillator (40) is operatively coupled to the tank circuit (100) for driving the tank circuit (100) into oscillation. A phase detector (94) monitors a phase shift between an output of said oscillator and oscillation of tank circuit. Weight on the seat is functionally related to the monitored phase shift.
Claims16
An apparatus for sensing weight on a vehicle seat, said apparatus comprising:
- variable inductance sensor means mounted in said seat for providing a variable inductance value functionally related to the weight on said seat;
- oscillator means for driving said variable inductance sensor means into oscillation;
- and
- means for monitoring a phase shift between an output of said oscillator means and oscillation of said variable inductance sensor means, weight on said seat being functionally related to said monitored phase shift.
An apparatus for sensing weight of an occupant on a vehicle seat in an occupant restraint system, said apparatus comprising:
- variable inductance sensor means mounted in said seat for providing a variable inductance value functionally related to the occupant's weight on said seat;
- capacitor connected in parallel across said variable inductance sensor means, said capacitor and said variable inductance sensor means forming a tank circuit;
- oscillator means operatively coupled to said tank circuit for driving said tank circuit into oscillation;
- and
- means for monitoring a phase shift between an output of said oscillator means and oscillation of said tank circuit, weight on said seat being functionally related to said monitored phase shift.
Dependencies are inferred from the claim text.