GB1579487A - Anti-theft device for motor vehicles - Google Patents

Abstract

The anti-theft apparatus comprises an alarm circuit connected to an intermittence circuit (31, 32, 33) in order to actuate the horn of the motor vehicle. The alarm circuit is controlled by a first circuit (29) capable of sensing the voltage drop of the battery of the motor vehicle, when a lamp lights up on opening a door of the motor vehicle, by a second circuit (26) sensitive to the closing of a contact following the starting of the engine, or by a third circuit (27) comprising a contact sensitive to the mechanical vibrations due to knocks or jolts imparted to the motor vehicle. The first circuit comprises a delayer (30) to enable the user to get into the motor vehicle. A general switch (18) can bypass all these circuits which become supplied through a timer circuit (28) to enable the user to get out of the motor vehicle. <IMAGE>

Description

(54) ANTI-THEFT DEVICE FOR MOTOR VEHICLES (71) We, BELSA ESTABLISHMENT, a Company organised under the Laws of Liechtenstein, of 9495 Triesen (Liechtenstein), do hereby declare this invention, for which we pray that a Patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to an electronic anti-theft device for motor vehicles which has, compared with known devices, the advantages of a triple detection means; a first of which gives an alarm for example with the opening of a door linked to the inside light of the cabin; the second giving the alarm for example when an electric contact is closed in particular when the engine ignites; and the third which gives the alarm for example when even light mechanical impacts are impressed on the vehicle.

These three alarm means are controllable by means of a general switch connected preferably to a delay means to give for example the owners of the vehicle an opportunity to get out of the motor vehicle, and close the doors or to enter comfortably without operating the alarm.

According to the invention there is provided an electronic anti-theft device for motor vehicles having three detection circuits connected to or connectible to a common acoustic alarm, the first of said detection circuits being connectible in the vehicle electric circuitry to cause actuation of the alarm in response to a fall of voltage in the battery of the vehicle caused by the illumination of a courtesey light or courtesey lights of the motor vehicle upon the opening of a door of the vehicle, the first circuit including an amplifier and a delay means to cause a delay between the illumination of said light or lights and the actuation of the alarm, the second of said detection circuits being connectible in the vehicle engine to cause actuation of the alarm when the vehicle ignition circuit is closed upon starting of the vehicle engine, and the third of said detection circuits including an electric contact operable by the effect of mechanical vibration caused by the application of force to the vehicle, the device further including a common isolator means actuation of which can render all of said three detection circuits inoperative, and intermittent control means to cause said alarm, when operated, to operate intermittently.

For better clarification, the attached drawings shown a preferred non-limiting embodiment of the invention. In the drawings: Figure 1 shows diagrammatically the device in its fundamental parts; Figure 2 illustrates the various units of the device of Figure 1; and Figures 3A and 3B respectively are circuit diagrams together showing the various electronic components of the device of Figure 1.

The device shown in Figure 1 comprises a box 10 upon the front panel of which are located telltale lamps 11 and 12, and a regulation means 13 which is sensitive to vibrations.

Numerals 1, 2, 3, 4 indicate the terminals which are respectively connected to the following: the ignition circuit of the engine, for example, to the ignition coil 19 through the main switch 18 which is also connected to earth; the positive pole of the vehicle battery 22 through the valve 23; earth through contacts 24, 25 actuable upon switching on of the ignition circuit; and the hooter, horn or siren 20 of the vehicle by means of the switch 21.

In Figure 2 is shown at 18 the main isolator switch already seen in Figure 1; at 28 the units or the time delay circuits for leaving the motor vehicle with delay of 30 seconds; at 29 the unit for detecting fall in battery voltage; at 30 an integrator unit which introduces a delay of 7 seconds after the opening of the door; at 31 a delay unit of the duration of 30 seconds for the alarm; at 32 the interruption unit of a multi-vibrator; at 33 the output circuit of a relay; at 34 the unit for operation by the ignition circuit; at 27 the unit of the vibrator circuit and at 26 the unit of the control circuit of the switch.

In the diagram of Figures 3A and 3B the vibration sensitive means herein termed a vibrator, is indicated by Vbl, whilst the input 1,2, 3,4 correspond to those of Figures 1 and 2.

The operation of the diagram of Figures 3A and 3B is as follows: The circuit, having been fed with power by the closing of the isolater switch 18 connected to the terminal 1 to earth, is held locked in the resting position for a time so as to permit the user to leave the motor vehicle comfortably. After this first time delay the anti-theft device becomes active and all the controls are pre-disposed ready to detect unauthorised interference with the vehicle.

The detection of such interference may occur in any of the three ways set forth above and namely; 1) through a circuit capable of detecting the effect on the battery corresponding to the switching on of a lamp of 3w current (about 250mA) which is the lamp of minimum power and which is lit on opening a door; this control acts on the alarm after a delay of about 7 seconds. The delay timing is adapted to permit the user to enter the motor vehicle and switch off the general switch since the opening of the door would otherwise set off the alarm.

2) By the closing of a contact to earth connected to the terminal point 3 of the antitheft device. This control sets the alarm immediately in action for the duration of 30 seconds.

3) By the closing of a contact which is sensitive to such vibrations as are caused by knocks and impacts. This control also sets off the alarm immediately for a duration of 30 seconds.

Once inserted the said three circuits having been made operative they cannot be eliminated except by the opening of the general switch 18.

In their turn, the said control circuits do not act directly on the output circuits, but pass through an intermittently operating circuit which provides a means for opening and closing of the contacts of an output relay, so as to modulate the same acoustic alarm in an on-off manner. The alarm may be for example a hooter, a siren or pneumatic or electric horn.

Reference is now made in detail to Figures 3A and 3B.

The circuit is fed through the switch 18 to earth, and has a first timing switch constituted by R15 and Cli having a time constant for 30 seconds and controlling a reset circuit TR3, C9 for resetting (restoring) the two integrators IcI and Ic (terminal 3).

On closing switch 18 the timing terminals 4 of the integrators are at low voltage (- IV).

However, at the end of the initial delay of 30 seconds the voltage is brought to values near those of feeding ( = 10V). At this point, the circuits may be controlled in the following ways.

Firstly by detection of the effect on the supply of the switching on of one of the vehicle lights such as the interior light caused by opening a door. The circuit concerned in this function is constituted by C1, D1, TR1, R1, D2, R2 and C2. C1 has the function of blocking the continuous current whilst allowing the variation voltage signals caused by switching on of a light to pass.

When this occurs, the transistor TR1 functions as an amplifier with common base and is polarised directly. This permits a conduction between the collector and emitter and from here to earth through D1 with consequent instantaneous lowering of the voltage on the point 2 of the integrator Icl. This command to the integrator produces a high output on the terminal 3 of same. The resistor R1 and the diode D2 serve to protect the transistor TR1 and the integrator Icl against damage. The condenser C2 serves to isolate the circuit from spurious commands due to external incidents such as for example caused by motions of engines of other motor vehicles or by various electric discharges.

At the same moment, whereas with the command to the integrator the timing starts and the voltage to the terminal 6 (THRESHOLD) and 7 (DISCHARGE) commence to rise by the action of the circuit R3, C3, when the voltage reaches the value of the voltage which is on the terminal 5 (control), the output on the point 3 returns to a low value. The whole cycle occurs in about 7 seconds. We now see produced a variation of output at the terminal 3 of Ic1. Normally the output on terminal 3 is low and condenser C12 through D5 and R7 is loaded to the feed voltage of the point 2 of Ic2 which is at a higher value ( =1OV).

When, on the other hand, the output of Icl is high the condenser C12 discharges through the resistor R9. After 7 seconds the output of Ic1 returns to a low value and subsequently through C12 (which may be considered a short circuit at the starting moment of charging) and D5, the terminal 2 of Ic2 for an instant becomes low with consequent command to the said integrator Ic2.

At this point, this sequence is repeated through Ic2 except that the duration of the cycle is 30 seconds and it is during this time that the alarm is operative.

The control at Ic2 (terminal 2) other than from the circuit described, may occur also through a closing of a contact to earth con nected to connection 3 of the anti-theft device when the engine ignition circuit is operative. The circuit concerned in this operation is formed by D4, R18, C13, and R24 and its operation is identical to the circuit disposed between the two integrators Icl and Ic2. The resistor R24 is a protective resistor adapted to obviate damage up to the integrator Ic2 when the anti-theft device is not fed and if there is instead a closing to earth through pulsator.

The three condensers C4, C7 and C8 are for protection to obviate damage to the circuits of the integrators or false command to same.

In addition to Ic2, the command may be given from the vibrator Vbl which is adjustable by means of a micrometric screw, or better from its closing to earth a closing contact, which closing is evidenced by the lighting of LEDZ (R8 is a resistance to limit the current).

The commands by the contact to earth on the terminal 3 or the vibrator are immediate because they do not pass through Ic1.

The output of Ic2 connected through an AND gate constituted by D7, D8, and R14, becomes high when the signal is impressed on and permits the multivibrator TR5, TR6 which oscilates freely with half cycles of 1 second and 2 seconds controlling the output circuit R16, R17 and TR4, which in its turn excites the coil of the relay R1. When the relay is exited, the alarm sounds. The diode Dlo serves a protection against reverse currents which occur on terminating the command to the relay.

Across the contacts of the relay, there is a condenser C16 which provides for the impuses which the charge produces on the feeding.

To obviate such variations of the load, having consequences on the operation of the integrators Icl and Ic2, these are decoupled from the feed through R6 and C5.

A brief consideration may be made on the intermittantly operating circuit. This is constituted by a common multivibrator or a stable oscillator which has the timing circuit on balance to obtain two different half cycles.

That is the group R20, C14 has a constant of time double with respect to a group R21, C15.

In conclusion, after 30 seconds duration of intermittent operation of the alarm, the terminal 3 of Ic2 becomes low again, this face brings about interruption of the transistor TR2 through R10 and R11. Therefore, through R13 and C10 there is a new command to the transistor TR3 which in its turn brings about a low value after 1 second at the terminals 4 of the two integrators to reestablish them (reset).

This zero setting circuit is adapted to prevent the last de-exitation command to the acoustic warning from the anti-theft device back into operation.

The anti-theft device described therefore provides the following delay and operation periods: a) Time for leaving vehicle - 30 seconds Time for entering vehicle - 7 seconds Time of duration of alarm - 30 seconds Alarm operates cyclically 1 second off - 2 seconds on.

b) Command to alarm delayed by 7 seconds after detector of voltage supply variations end then 30 seconds alarm operation.

Pulsating command to earth immediate with duration 30 seconds. Vibrator command immediate with duration 30 seconds. Protection against any reversals of feed through the diode D3. Visulization of feed through LED 1 (R23 limitation resistor).

WHAT WE CLAIM IS: 1. An electronic anti-theft device for motor vehicles having three detection circuits connected to or connectible to a common acoustic alarm, the first of said detection circuits being connectible in the vehicle electric circuitry to cause actuation of the alarm in response to a fall of voltage in the battery of the vehicle caused by the illumination of a courtesey light or courtesey lights of the motor vehicle upon the opening of a door of the vehicle, the first circuit including an amplifier and a delay means to cause a delay between the illumination of said light or lights and the actuation of the alarm, the second of said detection circuits being connectible in the vehicle engine to cause actuation of the alarm when the vehicle ignition circuit is closed upon starting of the vehicle engine, and the third of said detection circuits including an electric contact operable by the effect of mechanical vibration caused by the application of force to the vehicle, the device further including a common isolator means actuation of which can render all of said three detection circuits inoperative, and intermittent control means to cause said alarm, when operated, to operate intermittently.

2. A device according to Claim 1, wherein the delay introduced by said delay means is of the order of 7 seconds.

3. A device according to Claim 1 or 2, wherein there is a second delay means arranged to introduce a delay between the operation of the isolator to render the said three circuits operative and the becoming operative of said three detection circuits, said delay being of the order of 30 seconds.

4. A device according to any preceding claim, wherein the operation of the alarm is adapted to be timed by a timer circuit of the device so that the alarm, when actuated will operate for a period of 30 seconds.

5. A device according to any preceding claim, wherein the sensitivity of the electric

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. nected to connection 3 of the anti-theft device when the engine ignition circuit is operative. The circuit concerned in this operation is formed by D4, R18, C13, and R24 and its operation is identical to the circuit disposed between the two integrators Icl and Ic2. The resistor R24 is a protective resistor adapted to obviate damage up to the integrator Ic2 when the anti-theft device is not fed and if there is instead a closing to earth through pulsator. The three condensers C4, C7 and C8 are for protection to obviate damage to the circuits of the integrators or false command to same. In addition to Ic2, the command may be given from the vibrator Vbl which is adjustable by means of a micrometric screw, or better from its closing to earth a closing contact, which closing is evidenced by the lighting of LEDZ (R8 is a resistance to limit the current). The commands by the contact to earth on the terminal 3 or the vibrator are immediate because they do not pass through Ic1. The output of Ic2 connected through an AND gate constituted by D7, D8, and R14, becomes high when the signal is impressed on and permits the multivibrator TR5, TR6 which oscilates freely with half cycles of 1 second and 2 seconds controlling the output circuit R16, R17 and TR4, which in its turn excites the coil of the relay R1. When the relay is exited, the alarm sounds. The diode Dlo serves a protection against reverse currents which occur on terminating the command to the relay. Across the contacts of the relay, there is a condenser C16 which provides for the impuses which the charge produces on the feeding. To obviate such variations of the load, having consequences on the operation of the integrators Icl and Ic2, these are decoupled from the feed through R6 and C5. A brief consideration may be made on the intermittantly operating circuit. This is constituted by a common multivibrator or a stable oscillator which has the timing circuit on balance to obtain two different half cycles. That is the group R20, C14 has a constant of time double with respect to a group R21, C15. In conclusion, after 30 seconds duration of intermittent operation of the alarm, the terminal 3 of Ic2 becomes low again, this face brings about interruption of the transistor TR2 through R10 and R11. Therefore, through R13 and C10 there is a new command to the transistor TR3 which in its turn brings about a low value after 1 second at the terminals 4 of the two integrators to reestablish them (reset). This zero setting circuit is adapted to prevent the last de-exitation command to the acoustic warning from the anti-theft device back into operation. The anti-theft device described therefore provides the following delay and operation periods: a) Time for leaving vehicle - 30 seconds Time for entering vehicle - 7 seconds Time of duration of alarm - 30 seconds Alarm operates cyclically 1 second off - 2 seconds on. b) Command to alarm delayed by 7 seconds after detector of voltage supply variations end then 30 seconds alarm operation. Pulsating command to earth immediate with duration 30 seconds. Vibrator command immediate with duration 30 seconds. Protection against any reversals of feed through the diode D3. Visulization of feed through LED 1 (R23 limitation resistor). WHAT WE CLAIM IS:

1. An electronic anti-theft device for motor vehicles having three detection circuits connected to or connectible to a common acoustic alarm, the first of said detection circuits being connectible in the vehicle electric circuitry to cause actuation of the alarm in response to a fall of voltage in the battery of the vehicle caused by the illumination of a courtesey light or courtesey lights of the motor vehicle upon the opening of a door of the vehicle, the first circuit including an amplifier and a delay means to cause a delay between the illumination of said light or lights and the actuation of the alarm, the second of said detection circuits being connectible in the vehicle engine to cause actuation of the alarm when the vehicle ignition circuit is closed upon starting of the vehicle engine, and the third of said detection circuits including an electric contact operable by the effect of mechanical vibration caused by the application of force to the vehicle, the device further including a common isolator means actuation of which can render all of said three detection circuits inoperative, and intermittent control means to cause said alarm, when operated, to operate intermittently.

2. A device according to Claim 1, wherein the delay introduced by said delay means is of the order of 7 seconds.

3. A device according to Claim 1 or 2, wherein there is a second delay means arranged to introduce a delay between the operation of the isolator to render the said three circuits operative and the becoming operative of said three detection circuits, said delay being of the order of 30 seconds.

4. A device according to any preceding claim, wherein the operation of the alarm is adapted to be timed by a timer circuit of the device so that the alarm, when actuated will operate for a period of 30 seconds.

5. A device according to any preceding claim, wherein the sensitivity of the electric

contact operable by mechanical vibration is controllable by a micro-metric screw of the device.

6. An anti-theft for motor vehicles substantially as hereinbefore described with reference to the accompanying drawings.