Control system for a plurality of vehicle safety devices

• US 5,424,584 A
• Filed: 03/09/1993
• Issued: 06/13/1995
• Est. Priority Date: 03/19/1992
• Status: Expired due to Fees

• Current Assignee: Airbag Systems Company Limited
• Original Assignee: Airbag Systems Company Limited
• Inventors: Matsuda, Norio, Okano, Masami
• Primary Examiner(s): Stephan, Steven L.
• Assistant Examiner(s): Krishnan, Aditya
• Application Number:
  US08/028,228
• Time in Patent Office: 826 Days
• Field of Search: 307/10.1, 340/436, 340/438, 280/734, 280/735, 180/282
• US Class Current: 307/10.1
• CPC Class Codes: B60R 21/0173 Diagnostic or recording means therefor

Abstract

A control system for a plurality of vehicle safety devices has a feeder circuit and a check current supplying circuit. A plurality of actuating elements are arranged in the feeder circuit in parallel relation, and at the same time, they are arranged in the check current supplying circuit in serial relation. When a switching element is turned ON in accordance with a trigger signal coming from a collision judging circuit, an electric current flowing through the feeder circuit is caused to flow through the actuating elements in parallel. The check current flows to the actuating elements in series. The voltage generated between opposite ends of the serial circuit of the actuating elements in the check current supplying circuit is compared with a predetermined allowable range of voltage in a malfunction judging current, and when the voltage between the opposite ends is outside the predetermined allowable range of voltage, a malfunction detecting signal is outputted from the malfunction judging circuit.

Claims

1. A control system for first and second vehicle safety devices, comprising:

(a) a feeder circuit having a power source, first and second actuating elements of said vehicle safety devices being arranged in parallel relation to each other in said feeder circuit, input ends of said first and second actuating elements being connected to said power source, and output ends of said first and second actuating elements being connected to each other to form a connecting point;

(b) a collision judging means for judging whether or not a vehicle collision has occurred so that a trigger signal is outputted therefrom when said collision judging means judges that a vehicle collision has occurred;

(c) switching means arranged in said feeder circuit, said switching means being turned ON responsive to said trigger signal to supply electric current from said power source to said actuating elements, thereby actuating said vehicle safety devices;

(d) a check current supplying circuit for supplying check current from said input end of said first actuating element to said input end of said second actuating element via said connecting point, said check current serially flowing through said first and second actuating elements; and

(e) a malfunction judging means for comparing a voltage generated between said input ends of said first and second actuating elements with a predetermined allowable range of voltage so that a malfunction detection signal is outputted from the malfunction judging means when said voltage generated between said input ends is outside said predetermined allowable range of voltage.

2. A control system according to claim 1, in which said input ends of said first and second actuating elements are connected to each other to form a second connecting point, and said control system further comprises a check current preventing means for preventing the check current from flowing from said input end of said first actuating element to said input end of said second actuating element via said second connecting point.

3. A control system according to claim 2, in which said check current preventing means includes a diode, said diode being disposed between said second connecting point and said input end of said first actuating element, an anode of said diode being connected to said power source and a cathode of said diode being connected to said first actuating element.

4. A control system according to claim 2, in which said malfunction judging means includes a window comparator.

5. A control system according to claim 3, in which another diode is disposed between said second connecting point and said input end of said second actuating element, an anode of said another diode being connected to said power source, and a cathode of said another diode being connected to said second actuating element.

6. A control system according to claim 2, in which said check current supplying circuit includes an auxiliary power source connected to said input end of said first actuating element, and a constant current circuit connected to said input end of said second actuating element.

7. A control system for first and second vehicle safety devices, comprising:

(a) a feeder circuit having a power source, first and second actuating elements of said vehicle safety devices being arranged in parallel relation to each other in said feeder circuit, input ends of said first and second actuating elements being connected to each other to form a connecting point, said connecting point being connected to said power source;

(b) a collision judging means for judging whether or not a vehicle collision has occurred so that a trigger signal is outputted therefrom when said collision judging means judges that a vehicle collision has occurred;

(c) switching means arranged in said feeder circuit, said switching means being turned ON responsive to said trigger signal to supply electric current from said power source to said actuating elements, thereby actuating said vehicle safety devices;

(d) a check current supplying circuit for supplying check current from an output end of said first actuating element to an output end of said second actuating element via said connecting point, said check current serially flowing through said first and second actuating elements; and

(e) a malfunction judging means for comparing a voltage generated between said output ends of said first and second actuating elements with a predetermined allowable range of voltage so that a malfunction detection signal is outputted from the malfunction judging means when said voltage generated between said output ends is outside said predetermined allowable range of voltage.

8. A control system according to claim 7, in which said switching means includes first and second transistors which are connected in series respectively to said first and second actuating elements, said first transistor being disposed between said first actuating element and the ground, and said second transistor being disposed between said second actuating element and the ground.

9. A control system according to claim 7, in which said output ends of said first and second actuating elements are connected to each other to form a second connecting point, and said control system further comprises a check current preventing means for preventing the check current from flowing from said output end of said first actuating element to said output end of said second actuating element via said second connecting point.

10. A control system according to claim 9, in which said check current preventing means includes a diode, said diode being disposed between said second connecting point and said output end of said second actuating element, an anode of said diode being connected to said second actuating element and a cathode of said diode being connected to the ground.

11. A control system according to claim 10, in which another diode is disposed between said second connecting point and said output end of said first actuating element, an anode of said another diode being connected to said first actuating element and a cathode of said another diode being connected to the ground.

12. A control system according to claim 7, in which said check current supplying circuit includes an auxiliary power source connected to said output end of said first actuating element, and a constant current circuit connected to said output end of said second actuating element.