Anti-theft and alarm device for a vehicle

• US 4,223,298 A
• Filed: 06/07/1978
• Issued: 09/16/1980
• Est. Priority Date: 06/13/1977
• Status: Expired due to Term

• Current Assignee: Raymond Bernier
• Original Assignee: Raymond Bernier
• Inventors: Bernier, Raymond
• Primary Examiner(s): Waring, Alvin H.
• Application Number:
  US05/913,718
• Time in Patent Office: 832 Days
• Field of Search: 340/63, 340/64, 307/10 AT, 180/114
• US Class Current: 307/10.3
• CPC Class Codes: B60R 25/1018 Alarm systems characterised by features related to the general power supply

Abstract

The battery is connected to the terminal supplying the electrical system and the starter relay or the primary ignition circuit by a thyristor. The latter'"'"'s gate is controlled by a switch. Another switch makes it possible to establish a brief short-circuit to extinguish the thyristor. Any current draw then supplies the winding of an alarm relay.

Claims

1. An anti-theft device for a vehicle having a source of direct current ignition means and connecting means including key-operated switching means, between the said source and the said ignition means;

said anti-theft device comprising a solid-state controlled rectifier having an anode, a cathode and a gate;

said connecting means including first circuit means connecting the said source to the said anode through the said key operated switching means and second circuit means connecting the said cathode to the said ignition means;

said anti-theft device further comprising third circuit means, including a concealed temporarily closable switch, connecting the said key operated contact to the said gate.

2. Anti-theft device as claimed in claim 1, wherein said second circuit means include a diode having an anode connected to the cathode of said solid-state controlled rectifier and a cathode connected to the said ignition means, a capacitor connecting the anode of said diode to the said gate and a resistor connecting the anode of said diode to the earth.

3. An anti-theft device as claimed in claim 1, further comprising a diode having an anode connected to the cathode of said solid-state controlled rectifier and a cathode connected to the anode of said solid-state controlled rectifier, and a capacitor connecting the anode of said diode to said gate.

4. An anti-theft device for a vehicle having a source of direct current, ignition means and connecting means including key-operated switching means between the said source and the said ignition means, said anti-theft device comprising:

a solid-state controlled rectifier having an anode, a cathode and a gate;

first circuit means arranged for establishing through said solid-state controlled rectifier, a path of current conduction from said source which short-circuits the said ignition means;

second circuit means including serially connected resistor and capacitor, having a junction point connecting the said key-operated switching means to the earth;

solid-state switching means, having a control electrode and a main path of current flow from first to second electrodes, the first electrode being connected to the said key-operated switching means and the control electrode being connected to the said junction point;

a pulse transformer having a primary winding connecting said second electrode to the earth and a secondary winding connecting the gate of said solid-state controlled rectifier to the cathode thereof; and

third circuit means, including a concealed temporarily closable switch, connecting the anode of said solid-state controlled rectifier to the cathode thereof.

5. An anti-theft device as claimed in claim 4, wherein said second circuit means further comprise a switch serially connected with said key-operated switching means.