Automotive Systems Laboratory, Inc.

Donald A Duda

Leonard W Behr

Robert B Colten

James Gregory Stanley

Judson G McDonnell

Michael R Sewell

David Wilson

Steven J Anderson

Ryan N Steele

An anchor plate operatively coupled to a seat belt incorporates a slot that slideably engages an anchor bolt, which is biased therein by a spring. A tension in the seat belt causes a deflection of the spring and an associated motion of the anchor bolt in the slot, which is sensed by a proximity sensor on the anchor plate. In another aspect, a carriage is adapted to slide relative to a bracket, and a first spring is operative between the carriage and the bracket so as to bias the carriage relative to the bracket in a direction opposite to a first direction. Either the bracket is operatively coupled to a vehicle frame with an anchor bolt and the seat belt operatively engages the carriage, or vice versa. A tension in the seat belt, when reacted by the anchor bolt, causes an associated motion of the carriage in the first direction, which is sensed by a displacement sensor. In one embodiment, a second spring is operative between the carriage and the bracket so as to bias the carriage in the first direction relative to said bracket, thereby substantially eliminating slack. One embodiment of the displacement sensor comprises a magnetic sensor coupled to the bracket, which measures the magnetic field between a pair of magnets having crossed pole orientations, operatively coupled to the carriage. In another aspect, a second carriage and associated displacement sensor provide an additional measure of tension.

Seat belt tension sensor

A hydrostatic weight sensor incorporates a bladder having a plurality of cells in fluid communication with one another, and with the outlet of a check valve, the inlet of which is in fluid communication with a source of sensing fluid, preferably the atmosphere. A cell-filling restoring mechanism is operatively coupled to a portion of the cells of the bladder. When the applied load is removed from the hydrostatic weight sensor, the volume of those cells operatively coupled to the cell-filling restoring mechanism is restored, whereupon if the pressure becomes less than the local atmospheric pressure, then fluid is added to the bladder through the check valve, thereby restoring lost sensing fluid. A pressure sensor operatively coupled to the bladder generates a signal responsive to the pressure of the sensing fluid within the bladder, and a signal processor calculates the weight of the occupant therefrom.

Seat weight having self-regulating fluid filled bladder

An acceleration sensor comprises a tube formed of an electrically-conductive, nonmagnetic material; an annular magnetically-permeable element, such as an iron washer, encircling a longitudinal portion of the tube; a magnetic sensing mass in the tube which magnetically interacts with the washer so as to be magnetically biased towards a first or 'rest' position in the tube characterized in that a longitudinal portion of the sensing mass is situated within the portion of the tube encircled by the washer, the sensing mass being displaced from its rest position in the tube towards a second position therein in response to an accelerating force exceeding the magnetic bias thereon; and a switch operated by the sensing mass when the sensing mass is displaced to its second position in the tube. The instant accelerometer features a low threshold magnetic bias of the sensing mass to provide a quickened sensing mass response to acceleration inputs of short duration; and a magnetic bias which increases in a substantially linear manner with increasing sensing mass displacement from its rest position towards its second position within the tube.

Quick-response accelerometer

An acceleration sensor comprises a tube formed of an electrically-conductive non-magnetic material; a magnetically-permeable element, such as a iron washer, proximate with the passage; and a sensing mass in the passage comprising a pair of permanent magnets and a spacer whose magnetic permeability increases with increasing temperature, with the magnets being secured to the opposite sides of the spacer so as to place a pair of like magnetic poles in opposition. In operation, the sensing mass interacts with the iron washer so as to be magnetically biased to a first position in the passage, while the magnetic-permeability of the spacer and, hence, the magnetic flux generated by the sensing mass adjusts to maintain a nearly constant threshold magnetic bias irrespective of variations in sensor temperature. The sensing mass is displaced in response to acceleration of the housing from its first position in the passage towards a second position therein when such acceleration overcomes the threshold magnetic bias, while the tube itself interacts with the sensing mass to provide magnetic damping therefor. Upon reaching the second position in the tube, the sensing mass electrically bridges a pair of contacts to indicate that a threshold level of acceleration has been achieved. An electrical coil is secured proximate with the iron washer which, when energized, reversibly magnetizes the latter, whereby the sensing mass is either repelled to the second position in the tube or more strongly biased towards the first position therein.

Accelerometer with dual-magnet sensing mass

An acceleration sensor comprises a tube formed of an electrically-conductive non-magnetic material; a stop defining an end of the tube which moves longitudinally thereof in response to temperature; a magnetically-permeable element, such as a iron washer, proximate with the end of the tube; and a sensing mass in the tube comprising a pair of permanent magnets secured to the opposite sides of an iron spacer so as to place a pair of like magnetic poles thereof in opposition. In operation, the sensing mass interacts with the iron washer so as to be magnetically biased against the stop, while the stop moves longitudinally of the tube to maintain a nearly constant threshold magnetic bias on the sensing mass irrespective of variations in sensor temperature. The sensing mass is displaced in response to acceleration of the housing from its first position against the stop towards a second position in the tube when such acceleration overcomes the magnetic bias, while the tube itself interacts with the sensing mass to provide magnetic damping therefor. Upon reaching the second position in the tube, the sensing mass bridges a pair of electrical contacts with an electrically-conductive surface thereof to indicate that a threshold level of acceleration has been achieved. An electrical coil is secured proximate with the iron washer which, when energized, reversibly magnetizes the latter, whereby the sensing mass is either repelled to the second position in the tube or more strongly biased against the stop.

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Novi, MI, United States of America

Donald A Duda