US 5,996,421 AGranted

Seat belt tension sensor employing flexible potentiometer

AssigneeBreed Automotive Technology, Inc.

InventorHarald Snorre Husby

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Abstract

Seat belt tension is determined by measuring the resistance of a flexible potentiometer which is deformed to produce a controlled change in resistance with increased belt tension. A seat belt mounting has a spring which allows limited extension of the seat belt in response to belt tension. A flexible potentiometer is mounted to the spring so that spring deformation produces a change in resistance which can be directly correlated to belt tension. Belt tension is input to an airbag deployment logic which may incorporate a seat position sensor, a weight-on-seat sensor and various other sensors which detect the existence, size and direction of any crash. The logic draws conclusions from the tension sensor in the seat belt and other sensors to determine if deployment of the front passenger airbag is likely to be advantageous to an occupant of the front passenger seat.

Claims14

Dependent claims

An apparatus for measuring tension in a seat belt comprising:

a belt bracket for mounting a seat belt, the bracket having portions defining a belt retaining hole and portions forming a means for mounting the bracket;
a belt passing through the hole in the belt bracket and forming a loop which encloses a cross member which is formed as a portion of the bracket, the cross member being spaced from the portion forming the means for mounting and the cross member defining a direction from the means for mounting toward the cross member;
a spring positioned between the loop formed by the belt and the cross member so that motion of the loop in the defined direction away from the means for mounting, draws the spring toward the cross member elastically deforming the spring;
and
a sensor positioned between the loop and the cross member so that motion of the loop in the defined direction away from the means for mounting, draws the sensor toward the cross member elastically deforming the sensor, so tension on the belt can be determined by monitoring an output from the sensor which is correlated with elastic deformation of the sensor.

2 more elements

Dependencies are inferred from the claim text.