Device for preventing the theft of motor vehicles

• US 4,852,681 A
• Filed: 07/06/1988
• Issued: 08/01/1989
• Est. Priority Date: 07/09/1987
• Status: Expired due to Fees

• Current Assignee: N E I M A N
• Original Assignee: N E I M A N
• Inventors: Bombled, Jean
• Primary Examiner(s): Bertsch, Richard A.
• Application Number:
  US07/215,601
• Time in Patent Office: 391 Days
• Field of Search: 180/287, 307/10 AT, 340/63, 340/64
• US Class Current: 180/287
• CPC Class Codes: B60R 25/045 by limiting or cutting the electrical supply to the propulsion unit

Abstract

An anti-theft device for motor vehicles which operates by cutting off the electrical supply to the ignition by a relay supplied by a central electronic unit which is connected in series with the "on" contact of the anti-theft steering lock of the vehicle characterized in that the relay is connected to the central unit through at least one transistor and to ground by a switch device which is maintained open while the engine is running.

Claims

1. In an anti-theft device for motor vehicles operating by cutting off the electrical supply to the engine ignition circuit by means of a relay which is movable from a first closed position to a second open position when energized by a control circuit including a central electronic unit which is connected in series with the "on" contact of the vehicle'"'"'s anti-theft steering switch when in a monitoring mode, the improvement of

(a) at least one transistor connected between the relay and the central unit through which transistor the central unit can energize the relay when in a monitoring mode and the "on" contact of the anti-theft steering switch is closed,

(b) a switch device for grounding the relay when the engine is not running, and

(c) said switch device being open from ground while the engine is running.

2. The anti-theft device of claim 1, wherein said transistor is connected to ground through said switch device.

3. The anti-theft device of claim 1, wherein a second transistor is provided mounted in a cascade with said first transistor, through which the relay is energized by the central unit.