VEHICLE AIR CUSHION ACTUATION AND MONITORING CIRCUIT

• US 3,633,159 A
• Filed: 11/10/1970
• Issued: 01/04/1972
• Est. Priority Date: 11/10/1970
• Status: Expired due to Term

• Current Assignee: John Auzins, Ned E. Dillman
• Original Assignee: John Auzins, Ned E. Dillman
• Inventors: Dillman, Ned E., Auzins, John
• Primary Examiner(s): Waring, Alvin H.
• Application Number:
  US05/088,404
• Time in Patent Office: 420 Days
• Field of Search: 340/52R,52H,53 200/61.45 180/91,103,104 280/150
• US Class Current: 280/735
• CPC Class Codes: B60R 21/0176 for firing circuits using only mechanical switches as collision detecting means, in series with pyrotechnic fuses

Abstract

A vehicle air cushion actuation and monitoring circuit for preventing injury to passengers in the event of a collision. The actuation circuit includes an electrically operated actuator connected between first and second normally open accelerationresponsive switches which are in turn connected across a source of direct current firing potential. Resistors connected in parallel with the switches establish a reference potential at a junction between one of the switches and the actuator which is monitored by a detector which provides an output which energizes a lamp when the voltage at the junction rises above or drops below the reference potential by predetermined amounts. The output of the detector also activates a latch circuit which maintains the detector output. A capacitor is charged from a constant current source in response to an output from the detector and a double timing circuit responsive to the charging of the capacitor controls a latch interrupt circuit and a permanent recorder.

Claims

1. In a passenger conveyance provided with a safety device adapted to be actuated by electrically operated actuator means;

the combination of a control circuit for operating said actuator means and adapted to be connected to a source of direct current potential, said control circuit comprising first and second normally open condition-responsive switch means connected to opposite sides of said actuator means, detector means connected to a junction between said first condition-responsive switch means and said actuator means, means normally establishing a reference potential at said junction when both the said first and second condition-responsive switch means are open, said detector means providing an output when the voltage at said junction attains a predetermined potential above or below said reference potential, indicator means adapted to be energized in response to the output of said detector means, latch means responsive to an output from said detector means for maintaining the output from said detector means irrespective of the potential at said junction, recorder means, time delay means responsive to the output of said detector means for deactivating said latch means after a first interval of time, and for energizing said recorder means if the output of said detector means continues for a second interval of time subsequent to deactivation of said latch means.

2. The invention defined in claim 1 wherein said time delay means comprises a capacitor, a constant current source for charging said capacitor, semiconductor switch means connected in parallel with said capacitor and normally conducting to prevent charging of said capacitor from said constant current source, means responsive to an output from said detector means for rendering said first semiconductor switch means nonconductive to permit charging of said capacitor, a double timing circuit comprising second and third semiconductor switch means, a voltage divider network having respective junctions connected to said second and third semiconductor switch means for establishing first and second turn on potentials respectively, means connecting said second and third semiconductor switch means to said capacitor whereby said second and third semiconductor switch means are rendered conductive in succession as said capacitor charges above said first and second turnoff potentials respectively.

3. The inventIon defined in claim 1 wherein said detector means comprises a differential amplifier including first and second transistors having their emitter and collector electrodes connected across said source through a common emitter resistor, first and second voltage divider means respectively connected to the base electrodes of said first and second transistors and normally biasing said first transistor to saturation and said second transistor to cutoff, control means for switching said first transistor to cutoff and said second transistor to saturation in response to said predetermined potential, comprising a third transistor having a base connected to said junction, means including an emitter resistor connecting the emitter and collector electrodes of said third transistor across said source and normally biasing said third transistor between cutoff and saturation, first diode means having a cathode connected to the emitter of said third transistor and an anode connected to the base of said first transistor, and second diode means having an anode connected to the emitter of said third transistor and a cathode connected to the base of said second transistor.

4. In a passenger conveyance provided with an air cushion for preventing injury to passengers in the event of a collision and further provided with electrically operated actuator means for inflating said air cushion in response to current flow of a predetermined magnitude and duration, a control circuit for operating said actuator including oscillator means connected across a source of direct current potential for developing a pulsating output, voltage doubler means responsive to said pulsating output for developing an output voltage substantially twice the potential of said source, a capacitor connected across said voltage doubler means for storing a charge equal to the output voltage of said voltage doubler means, and first and second normally open acceleration-responsive switch means connected to opposite sides of said actuator means and connecting said actuator means across said capacitor to provide a discharge path for said capacitor upon simultaneous closure of said first and second switch means.