DIAGNOSTIC FIRING CIRCUIT ADAPTED FOR USE WITH INFLATABLE RESTRAINT SYSTEMS IN VEHICLES

• US 3,774,151 A
• Filed: 09/02/1971
• Issued: 11/20/1973
• Est. Priority Date: 09/02/1971
• Status: Expired due to Term

• Current Assignee: Charles J. Mcmillin, Donald J. Lewis
• Original Assignee: Charles J. Mcmillin, Donald J. Lewis
• Inventors: Lewis, Donald J., McMillin, Charles J.
• Primary Examiner(s): Waring, Alvin H.
• Application Number:
  US05/177,559
• Time in Patent Office: 810 Days
• Field of Search: 340/52,52H,53,61 200/61.45 180/91,103,104
• US Class Current: 280/735
• CPC Class Codes: B60R 21/0173 Diagnostic or recording means therefor
• CPC Class Codes: G01P 15/135 by making use of contacts which are actuated by a movable inertial mass

Abstract

An electric circuit assembly for transmitting a signal to initiate the inflation of a gas bag safety assembly in an automobile when the vehicle is involved in a collision. The circuit assembly is provided with diagnostic means to allow the driver to monitor the readiness of the circuit for operation and detect any malfunction in the assembly. Upon start-up of the vehicle, indicator means in the circuit assembly, in the form of a pair of warning lamps, indicates whether the circuit assembly is operating normally. One of the lamps is normally lit for a short period after the ignition switch is closed. The other lamp only becomes lit when the first lamp fails to light. The circuit is formed so as to operate properly despite the failure of various of its components.

Claims

1. A system for energizing the firing means of an inflatable safety system for a vehicle, comprising:

a first electrical power storage means;

a second electric power storage means connected to said first electrical power storage means so as to be charged from said first electrical power storage means;

an impact sensor switch disposed in said vehicle and having a first normal state, and a second state to which the switch moves in the event of impact;

circuit means connecting said first electrical power storage means, said second electrical power storage means, said impact sensor switch and said firing means so that at least one of said first and second electrical power storage means discharged through said firing means at such time as said switch moves into its second state;

a first signal means disposed in said circuit means in series with said second electrical power storage means so as to be energized at such time as said second electrical power storage means is being charged from said first electrical power storage means; and

a second signal means disposed in said circuit means in association with a monitoring means responsive to energization of said first signal means, said monitoring means being operative to prevent energization of said second signal means upon energization of said first signal means.

2. The system of claim 1 wherein said first electrical power storage means comprises the vehicle storage battery.

3. The system of claim 2 wherein said second electrical power storage means comprises a capacitor.

4. The system of claim 1 wherein said circuit means has such a configuration that each of said first electrical power storage means and said second electrical power storage means is capable of discharging through said firing means upon the movement of said impact sensor into its second condition, independent of the condition of the other power storage means.

5. The system of claim 3 wherein said capacitor is shunted with an element having a resistance substantially higher than that of said firing means.

6. The system of claim 5 wherein the vehicle ignition switch is connected between said battery and the balance of said circuit means so the battery is disconnected from the balance of the Circuit means at such time as the ignition switch is opened and the capacitor discharges through said element after opening of the ignition switch.

7. The system of claim 2 including a unidirectional conducting means connected between said battery and said second electrical power storage means, which allows said battery to charge said second electrical power storage means.

8. The system of claim 7 wherein said unidirectional conducting means comprises a plurality of diodes each of which is individually capable of carrying the full current drawn at such time as said vehicle battery discharges through said firing means.

9. The system of claim 1 wherein said second electrical power storage device is a capacitor.

10. The system of claim 9 wherein said first signal means constitutes a lamp disposed in the vehicle so as to be visible to the driver.

11. The system of claim 1 wherein said first electrical power storage means is grounded to the frame of the vehicle, and the circuit means is grounded to the frame of the vehicle so that said first signal means will not be energized unless both of said frame grounds are in operation.