SOLID-STATE BURGLAR ALARM SYSTEM FOR AUTOMOBILE

• US 3,643,214 A
• Filed: 11/23/1970
• Issued: 02/15/1972
• Est. Priority Date: 11/23/1970
• Status: Expired due to Term

• Current Assignee: Ronald E. Chan
• Original Assignee: Ronald E. Chan
• Inventors: Chan, Ronald E.
• Primary Examiner(s): Waring, Alvin H.
• Application Number:
  US05/091,916
• Time in Patent Office: 449 Days
• Field of Search: 340/53,63,64,65 307/10 180/114
• US Class Current: 307/10.3
• CPC Class Codes: B60R 25/04 operating on the propulsion system, e.g. engine or drive motor
• CPC Class Codes: B60R 25/1003 Alarm systems characterised by arm or disarm features
• CPC Class Codes: B60R 25/1004 Alarm systems characterised by the type of sensor, e.g. current sensing means using door lock sensors B60R25/1001
• CPC Class Codes: B60R 25/21 using hidden switches

Abstract

Solid-state burglar alarm system for operation with the courtesy light circuit of an automobile, wherein the alarm system includes a main switch hidden within the automobile for energizing and deenergizing the alarm system, means for disabling the ignition system, delay means for permitting the authorized operator to leave the automobile before the alarm is set, and delay means to permit the authorized operator to reenter the automobile and deenergize the alarm system before it would normally cause the alarm to sound.

Claims

1. In an automobile including a door-operated courtesy light circuit, a solid state burglar alarm system comprising a main switch located at a hidden location within the automobile and connected between the system and positive potential and operable to energize and deenergize the alarm system, a presetting circuit having an exit timer, a triggering circuit connected to the output of said presetting circuit and having an entrance timer, an alarm circuit connected to the output of said triggering circuit having a sound generating alarm device, a pulse generating circuit responding to the courtesy light circuit for generating a signal capable of energizing said triggering circuit, so that the triggering circuit is fired following timing out of the exit timer upon leaving the automobile and timing out of the entrance timer upon entering the automobile and energizing the courtesy light circuit, whereby upon closing the main switch an authorized person will have a given time to leave the automobile before the exit timer times out and arms the system, and thereafter the authorized person may enter the automobile through a door and deactivate the alarm system before the entrance timer times out without firing the alarm circuit, while an unauthorized person entering a door of the automobile will cause the alarm circuit to fire when the entrance timer times out.

2. The combination as defined in claim 1, wherein said triggering circuit includes an SCR having the gate connected to said signal generating circuit so that once the main switch is closed and the exit timer is timed out, closing of said courtesy light circuit fires said SCR to energize said entrance timer, and a unijunction transistor receiving the output of said entrance timer.

3. The combination as defined in claim 2, and an SCR in the presetting circuit having the cathode connected to ground and the anode connected mutually to positive potential and the cathode of the triggering circuit SCR, a diode connected between said entrance timer and ground to permit a pulse to be delivered to the unijunction transistor when the enTrance timer times out, whereby firing of both SCR'"'"''"'"'s applies a voltage to the entrance timer to commence timing out.

4. The combination as defined in claim 2, wherein means connects the anode of the triggering circuit SCR to the entrance timer and to positive voltage through a resistor.

5. The combination as defined in claim 4, and said presetting circuit including a unijunction transistor connected to the output of the exit timer, and means connecting the output of the unijunction transistor to the gate of the presetting circuit SCR.

6. The combination as defined in claim 1, wherein said pulse-generating means includes a voltage divider.

7. The combination as defined in claim 1, wherein said pulse generating means includes a pulse transformer circuit.

8. The combination as defined in claim 1, wherein said pulse-generating means includes a ferrite core coil adapted to coact with the courtesy light circuit fuse or a wire in the courtesy light circuit to detect current flow resulting from energizing the courtesy light circuit.

9. The combination as defined in claim 1, wherein said pulse-generating means includes a plastic core coil adapted to coact with the courtesy light circuit fuse or a wire in the courtesy light circuit to detect current flow resulting from energizing the courtesy light circuit, and an amplifier for amplifying the signal generated by the coil.

10. The combination as defined in claim 1, wherein the automobile includes an ignition system having breaker points and a high voltage coil connected thereto, and wherein said alarm system includes a line having a diode and being connected from the circuit side of the main switch to the points side of the high-voltage coil, whereby closing the main switch effectively connects the diode across the coil thereby killing any back EMF generated and disabling the ignition system to prevent starting the automobile.

11. The combination as defined in claim 1, and means bypassing the entrance timer to immediately energize said alarm circuit and the sound device in response to closing of switches operable by the hood and/or trunk.

12. The combination as defined in claim 1, wherein the automobile includes an ignition system having breaker points and a high-voltage coil connected thereto, and wherein a second switch operable simultaneously with said main switch is connected between ground and the points side of the high-voltage coil thereby disabling the ignition circuit when the second switch is closed.

13. In an automobile having an electrical system for powering headlights, courtesy lights, horn, ignition system or the like, a solid state burglar alarm system comprising a main switch located at a hidden location within the automobile and connected between the alarm system and the positive potential of the electrical system and operable to energize and deenergize the alarm system, an alarm circuit having a sound generating alarm device to be energized upon triggering of the alarm system, a triggering circuit having an entrance timer for delaying the output of the triggering circuit after an input signal is received thereby, means connecting the output of the triggering circuit to the alarm circuit whereby the alarm circuit will be energized in response to timing out of the entrance timer, a presetting circuit having an exit timer, wherein the presetting circuit is latched and the alarm system is armed upon timing out of the exit timer, means connecting the input of the presetting circuit to the main switch whereby closing the main switch energizes the presetting circuit to start timing out of the exit timer, a signal-generating circuit comprising a voltage sensor sensing any voltage drain in the electrical system except that which may be suppressed and energizing the triggering circuit upon sensing voltage drain to start the timing out of the entrance timer, and means bypassing the entrance timer to immediately energize said alarm circuit and the sound device in response to closing oF switches operable by the hood and/or trunk.

14. The combination as defined in claim 13, wherein the ignition system includes breaker points and a high-voltage coil connected thereto, and wherein said alarm system includes a line having a diode and being connected from the circuit side of the main switch to the points side of the high-voltage coil, whereby closing the main switch effectively connects the diode across the coil thereby killing any back EMF generated and disabling the ignition system to prevent starting the automobile.