VEHICLE INFLATABLE CUSHION ACTUATION AND MONITORING CIRCUIT
First Claim
1. In a passenger conveyance provided with an inflatable cushion adapted to be actuated by electrically operated actuator means the combination of:
- an actuation circuit for operating said actuator means and comprising a primary source of direct current, a storage capacitor, switch means connecting said storage capacitor to said primary source for charging said storage capacitor to provide a secondary source of direct current, first and second normally open acceleration responsive switch means connected to opposite sides of said actuator means and forming a series network connected to said primary source and said secondary source, means responsive to loss of said primary source for providing a discharge path through said series network fRom said secondary source, first voltage divider means normally establishing a predetermined voltage at a monitoring junction in said series network, indicator means, monitoring means comprising comparator means including second voltage divider means establishing first and second reference voltages at first and second reference junctions respectively, said comparator means further including first and second semiconductor means responsive to the voltage at said first and second reference junctions respectively and the voltage at said monitoring junction for developing a predetermined output when the voltage at said monitoring junction exceeds said first reference voltage or drops below said second reference voltage, said comparator means further including third semiconductor means responsive to the absence of charge accumulation by said secondary source when initially connected to said primary source by said switch means for developing said predetermined output, additional semiconductor means responsive to said predetermined output of said comparator means for energizing said indicator means.
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Accused Products
Abstract
The actuation circuit includes a plurality of electrically operated actuators for controlling the inflation of a plurality of inflatable cushions located in a vehicle in response to closure of condition responsive switches. The series circuit formed by the switches and actuators is connected with a battery and a storage capacitor which form primary and secondary sources of direct current firing potential. The actuators are fired from the battery during a collision upon concurrent closure of the switches unless battery power is not available as a result of the collision in which case the actuators are fired from the storage capacitor. Circuitry is provided for monitoring the actuation circuit for malfunction of the switches and the cabling interconnecting the switches and actuators as well as for loss of either the primary or secondary sources of firing potential. The monitoring circuitry includes an indicator lamp which is initially energized during an exercise period each time the vehicle ignition switch is closed. A malfunction causes continued energization of the indicator lamp after the exercise period. Consequently, the driver is informed of any malfunction as well as any indicator lamp outage. A crash recorder is provided which includes upper and lower crash level indicators for providing post-collision determination of the q level of the crash. The recorder also includes a failure time indicator which records the amount of time a malfunction remains uncorrected and is automatically reset at any accelerated rate when the malfunction is corrected. The recorder further includes an air cushion inflation indicator and circuit interrupt which prevents operation of the failure time indicator in the event of air cushion deployment and cooperates with the lower crash level indicator to permit post-collision verification of cushion deployment subsequent to the crash.
18 Citations
6 Claims
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1. In a passenger conveyance provided with an inflatable cushion adapted to be actuated by electrically operated actuator means the combination of:
- an actuation circuit for operating said actuator means and comprising a primary source of direct current, a storage capacitor, switch means connecting said storage capacitor to said primary source for charging said storage capacitor to provide a secondary source of direct current, first and second normally open acceleration responsive switch means connected to opposite sides of said actuator means and forming a series network connected to said primary source and said secondary source, means responsive to loss of said primary source for providing a discharge path through said series network fRom said secondary source, first voltage divider means normally establishing a predetermined voltage at a monitoring junction in said series network, indicator means, monitoring means comprising comparator means including second voltage divider means establishing first and second reference voltages at first and second reference junctions respectively, said comparator means further including first and second semiconductor means responsive to the voltage at said first and second reference junctions respectively and the voltage at said monitoring junction for developing a predetermined output when the voltage at said monitoring junction exceeds said first reference voltage or drops below said second reference voltage, said comparator means further including third semiconductor means responsive to the absence of charge accumulation by said secondary source when initially connected to said primary source by said switch means for developing said predetermined output, additional semiconductor means responsive to said predetermined output of said comparator means for energizing said indicator means.
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2. In a passenger conveyance provided with an inflatable cushion adapted to be actuated by electrically operated actuator means the combination of:
- an actuation circuit for operating said actuator means and comprising a primary source of direct current, a storage capacitor, switch means connecting said storage capacitor to said primary source for charging said storage capacitor to provide a secondary source of direct current, first and second normally open acceleration responsive switch means connected to opposite sides of said actuator means and forming a series network connected to said primary source and said secondary source, means responsive to loss of said primary source for providing a discharge path through said series network from said secondary source, first voltage divider means normally establishing a predetermined voltage at a monitoring junction in said series network, first indicator means, monitoring means comprising comparator means including second voltage divider means establishing first and second reference voltages at first and second reference junctions respectively, said comparator means further including first and second semiconductor means responsive to the voltage at said first and second reference junctions respectively and the voltage at said monitoring junction for developing a predetermined output when the voltage at said monitoring junction exceeds said first reference voltage or drops below said second reference voltage, said comparator means further including third semiconductor means responsive to an open circuit condition between said primary and secondary sources upon closure of said switch means for developing said predetermined output, additional semiconductor means responsive to said predetermined output of said comparator means for energizing said first indicator means, recorder means including a series network connected across said primary source and comprising third acceleration responsive switch means and second and third indicator means, said third acceleration responsive switch means being adapted to close and complete said series network in response to a conveyance deceleration level of a magnitude sufficient to actuate said first and second acceleration responsive switch means, said second indicator means providing a permanent indication of current flow in said series network, and said third indicator means open circuiting said series network in response to inflation of said cushion, said recorder means further including resettable indicator means for indicating the duration of energization of said first indicator means.
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3. In a passenger conveyance provided with an inflatable cushion adapted to be actuated by electrically operated actuator means, the combination of:
- an actuation circuit for operating said actuator means and comprising a primary source of direct current, filtering meaNs including a filter capacitor connected with said primary source, a storage capacitor, means including a charging resistor and a first unidirectional conducting device connecting said storage capacitor to said primary source for charging said storage capacitor and providing a secondary source of direct current, first and second normally open condition responsive switch means connected to opposite sides of said actuator means and forming a series network connected to said primary source through said first unidirectional conducting device whereby said actuator means is energized from said primary source in response to concurrent closure of said first and second switch means, a second unidirectional conducting device connected in parallel with said charging resistor and providing a path for energizing said actuator means from said secondary source in the event of failure of said primary source, first voltage divider means normally establishing a predetermined voltage at a monitoring junction in said series network, indicator means, monitoring means comprising comparator means including second voltage divider means establishing first and second reference voltages at first and second reference junctions respectively, first and second semiconductor means responsive to the voltage at said first and second reference junctions respectively and to the voltage at said monitoring junction for developing a predetermined output when the voltage at said monitoring junction exceeds said first reference voltage or drops below said second reference voltage respectively, third semiconductor means connected with said secondary source and said filter capacitor for developing said predetermined output during the charging interval of said filter capacitor and for maintaining said predetermined output in the absence of charge accumulation by said secondary source, semiconductor latch means responsive to said predetermined output from said comparator means for maintaining the said predetermined output from said comparator means, fourth semiconductor means responsive to said predetermined output of said comparator means for energizing said indicator means, semiconductor unlatching means including a constant current source and a timing capacitor, said semiconductor unlatching means being connected with said semiconductor latch means for disabling said semiconductor latch means a predetermined interval of time after said predetermined output is received from said comparator means.
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4. The invention according to claim 3 wherein said first semiconductor means includes a differential amplifier comprising first and second transistors each having emitter base and collector electrodes, the base electrode of the first transistor being connected to said monitoring junction, the base electrode of said second transistor being connected with said first reference junction, constant current sink means connected with the emitter electrodes of said first and second transistors, the collector electrode of said first transistor being connected with said primary source and providing said predetermined output when the voltage at said monitoring junction exceeds said first reference voltage, said second semiconductor means comprising a transistor having its emitter connected with said monitoring junction, its base connected with said second reference junction and its collector connected with said primary source for developing said predetermined output when the voltage at said monitoring junction drops below said second reference voltage.
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5. The invention according to claim 3 wherein said third semiconductor means comprises first, second and third transistors, said first transistor being connected with said secondary source and said filter capacitor and rendered conductive during the charging of said filter capacitor in the absence of accumulation of charge on said secondary source, said second and third transistors being sequentially energized in response to energization of said first transistor to providE a latch circuit for said first transistor to maintain said output after said filter capacitor has reached a predetermined charge potential.
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6. The invention according to claim 3 wherein said semiconductor means for energizing said indicator means comprises first, second and third transistors, said first transistor having emitter and collector electrodes connected in series with said indicator means, said second transistor having its collector electrode connected with the base of said first transistor and means connecting its emitter electrode to ground, means normally biasing said second transistor into saturation for maintaining said first transistor at cut off, said third transistor having its collector electrode connected with the base electrode of said second transistor and its emitter electrode connected to ground, the base of said third transistor being connected with said latch means whereby said third transistor is rendered conductive when said predetermined output is received from said comparator means and said second transistor is rendered nonconductive to render conductive said first transistor and energize said indicator means.
Specification