GB2210484A

GB2210484A - Security system for a motor vehicle

Info

Publication number: GB2210484A
Application number: GB8722804A
Authority: GB
Inventors: Reginald Sidney Butcher
Original assignee: NEWTON HALL ELECTRONICS LIMITE
Current assignee: NEWTON HALL ELECTRONICS LIMITE
Priority date: 1987-09-29
Filing date: 1987-09-29
Publication date: 1989-06-07
Also published as: GB8722804D0

Abstract

The system comprises an electrical circuit which is adapted to be connected into the electrical circuitry of the vehicle and which is adapted to be armed by receiving electrical signals from the operation of a series of the mechanical and/or electrical controls of the vehicle in a specified sequence and/or within a specified duration time span. The system is adapted to actuate an alarm and/or to disconnect part or all of the electrical circuit of the vehicle required for operation of the vehicle if a specified sequence or duration for the input signals from controls of the vehicle is not achieved during a disarming operation whereby the system can react to an unauthorised attempt to operate the vehicle. The arming stage involves the actuation of at least one of the vehicle's controls which would not readily be actuated when the vehicle is in normal forward movement, eg reverse gear is selected. The invention also relates to a vehicle fitted with the system of the invention and to a method for rendering that vehicle secure by actuating the system. <IMAGE>

Description

TITLE: SECURITY DEVICE The present invention relates to a security device, notably to a security device and method for a road vehicle.

BACKGROUND TO THE INVENTION: When a vehicle is left unattended, there is a risk that it will be stolen and theft of and from motor vehicles is increasing. Many forms of physical and/or electronic devices have been proposed which either immobilise the vehicle and/or sound an alarm if unauthorised entry into and/or movement of the vehicle is attempted.

In one form of system, it has been proposed that the vehicle carry a key pad interlinked with the ignition circuit so that the driver must key in a coded number sequence which arms an alarm system and disables the ignition circuit of the vehicle until the same code is reinserted into the key pad by the driver. Alternatively, it has been proposed that a number of the switches normally found in the vehicle must be actuated in a required sequence in order to arm or disarm the alarm system. However, in both such systems the same code is often used to arm and disarm the security system.

Accidental arming of prior systems can occur during normal driving of the vehicle with attendant inconvenience and possibly dangerous effects. Also, many of the systems are based on immobilising the ignition system of the engine of a petrol driven vehicle and are not suitable for use on a diesel engined vehicle. Furthermore, the prior art devices are usually designed so that they automatically adopt the "armed" or operative condition soon after the ignition has been switched off. This is inconvenient and requires disclosure of the disarming code or sequence to a garage or other person required to move the vehicle, thus exposing the security of the system to abuse by such persons. Where the disarming code is the same as the arming code disclosure of the latter inherently discloses the former and negates any security.

I have now devised a system and method of operation which overcomes the above problems and which can be fitted as an accessory to existing vehicles as well as to new vehicles during their construction and to both diesel and petrol driven vehicles.

SUMMARY OF THE INVENTION: Accordingly, the present invention relates to a security system for a vehicle which system comprises an electrical circuit which is adapted to be connected into the electrical circuitry of the vehicle so as to actuate an alarm and/or to disconnect part or all of the electrical circuits of the vehicle required for operation of the engine of the vehicle which system is adapted to be armed and disarmed by a series of actions whereby the system can react to an unauthorised attempt to operate the vehicle, characterised in that the arming stage involves the actuation of at least one of the vehicle's controls which would not readily be actuated when the vehicle is in normal forward movement.Preferably, the invention is further characterised in that the disarming requires the operation of a plurality of the controls of the vehicle in a predetermined sequence, for example in a specified order and within a specified time limit.

The invention also provides a vehicle fitted with a security system of the invention connected to the electrical circuit of the vehicle so as to receive signals from a plurality of the controls of the vehicle to actuate its arming and disarming circuits.

The invention further provides a method for rendering secure a vehicle fitted with a system of the invention, which method comprises arming the system by operating at least two of the controls of the vehicle in a sequence not normally used in the normal forward motion of the vehicle and disarming the system by the operation of a plurality of the controls of the vehicle in a predetermined sequence.

Preferably, the arming of the system involves the selection of reverse gear before the ignition key is turned to one of its active positions for a specified time and then turned to its off position. Such a series of actions is virtually impossible to achieve during normal forward movement of the car so that the security system will not be activated during normal driving of the vehicle. Alternative controls to be used for the arming procedure could be the combination of the ignition switch and the fog lamp switches, since the latter are normally only active when the headlamps of the vehicle are switched on.

It is preferred that the armed condition of the system should not only serve to actuate an alarm if an attempt is made to start the engine of the vehicle, but also that it should disable the ignition and/or starter motor circuits of the vehicle. The system can cut out other circuits required for the normal operation of the vehicle, for example the operation of the fuel pump, or actuate the horn or headlights as the alarm.

Since the arming of the security system of the invention requires positive action by the driver, the vehicle can be left in its unsecured state for others to drive before they arm the system. Thus, a car can be left with a garage for servicing and the like with only the arming code disclosed to them. The disarming code need not be disclosed to them and its integrity is therefore not diminished.

The alarm system of the invention can be applied to all types of vehicle having an electric circuit as a part of the operating system of the vehicle. Thus, the invention can be applied to petrol or diesel engined vehicles as well as to electrically powered vehicles; and to land, air or water based vehicles, such as cars, trains or boats. For convenience, the invention will be described in terms of a conventional petrol driven road vehicle.

The system of the invention comprises an electrical circuit which is connected into the existing circuitry of the vehicle to receive signals from the operation of those controls selected for the arming and disarming stages. The electrical connection to the control may be made directly to the control itself, to any point in the ciruit it controls or indirectly via a terminal block or other distribution means, for example a block terminal connector, to which wires from the control are fed to centralise the wiring to the system of the invention. In order to reduce the risk of interaction between the various controls connected to the system of the invention, it is preferred to incorporate a capacitor in the connection for each control circuit to the system. Typically, the arming stage will involve the disabling of the ignition circuit of the vehicle and/or of the starter motor actuation circuit by means of suitable switches incorporated within the system and actuated according to whether the system is armed or disarmed.

The system of the invention will usually comprise an enclosure, for example a metal, plastic or other box-like structure within which the necessary circuitry is housed and having suitable electrical contacts to which the controls and circuits from the vehicle can be attached. The box-like structure is preferably so sized and shaped that it can readily be accommodated under the dashboard of the vehicle or in a similar readily accessible location for ease of installation. Desirably, the necessary circuitry for the system is potted in resin within the box-like structure or otherwise made resistant to tampering.

The system of the invention incorporates means by which the operation of the selected controls is to be monitored. It will usually be preferred that the controls be actuated in a specified sequence which incorporates a time limit for the successive operation of each of the controls or for an overall total time within which the whole sequence must be completed. The system of the invention therefore incorporates a programmable memory means, such as a microprocessor, to contain the desired predetermined operation sequence; and a timer circuit against which the operation of the controls is assessed. Such timer circuits, assessment and microprocessor circuits can be of conventional design and operation and a circuit diagram for a preferred embodiment of the electronic circuitry for use in the system of the invention is shown in Figure 1 of the accompanying drawings.

The system can draw the electrical power for its operation from the battery of the vehicle it serves. However, it may be desired to incorporate a battery within the system, for example a rechargeable battery fed from the main battery of the vehicle, so that the system is not incapacitated merely by disconnecting the vehicle battery.

Most motor vehicles are fitted with switches, gear levers, brake pedals or the like which actuate electrical circuits from which a signal to be fed to the system of the invention can be obtained. Such switches etc. will herein be denoted collectively as the controls of the vehicle. Such controls include those which are used in the arming stage and those which are used in the disarming stage of the operation of the system of the invention. Whilst the same controls may be used in part or all of both the arming and disarming stages, it is preferred that each stage use different controls so that the risk of accidental confusion of the two stages is minimised, apart from the possible use of the ignition switch in both stages.

Most motor vehicles are fitted with a combination key switch for starting the engine and actuating the ignition circuit.

This switch is denoted herein as the ignition switch and typically has four positions: (a) "Off" when the starting key can be inserted or withdrawn, (b) "Access" when certain accessories are made available for use, (c) "On" when the ignition system of a petrol engined vehicle is switched on, and (d) "Start" when the engine starter motor is to be used. For a diesel engined vehicle a similar switch is usually used, but this may have a further position between the "On" and the "Start" position when the pre-heaters for the combustion chambers are switched on. Since the ignition switch is usually required to actuate the electrical circuitry of the vehicle, it is preferred to incorporate operation of this switch into the arming and/or disarming stages of the operation of the system of the invention.

As indicated above, the arming stage usually will involve the operation of the reverse light circuit which is actuated when reverse gear is selected, or the combination of the head lamp and fog light switches, and the ignition switch in a predetermined sequence and timing. Typically, the arming stage will comprise the selection of reverse gear with the ignition switched off, then switching on of the ignition switch and switching it off after a set time interval, for example 2 to 5 seconds. It will be appreciated that other controls can be incorporated into the arming stage.

Typically, the controls to be operated in the disarming stage will be selected from the following functions: head lights, side lights, stop lights, rear fog light, windscreen wiper, windscreen washer, right-hand turn indicator, left-hand turn indicator, and rear window heater. Some vehicles have further functions controlled by switches such as rear window wiper, rear window washer, head lamp wiper, head lamp washer, and front fog lights. All of these "disarming" switches are available for the purpose of this invention and the number and combination of the switches used in the disarming stage can be selected by the user within broad ranges. However, we have found that adequate protection is achieved by the use of from three to six switches operated in a timed sequence.

A typical disarming sequence would be for example, firstly, ensure that all switches are in the "off" position; then switch the ignition switch to the "on" position. Now switch on the three or more of the "disarming" switches chosen from those available in the particular vehicle and which have been connected to the device of the invention when it wasinstalled in the vehicle. These "disarming" switches are momentarily switched on and off in a pre-determined sequence, optionally with a required tine interval between each.

It is also within the scope of the present invention to provide other controls linked into the circuit of the system of the invention which do not have any function in the operation of the engine or other features of the vehicle.

These "dummy" controls can be of any suitable form, eg.

rocker, toggle or the like electrical switches, and their operation can be included within either or both of the arming or disarming stages.

In order to enhance the security of the system of the invention, some of the controls can be given the function of "obstructing" switches which if switched on, even momentarily, will cancel out the effect of any correct switches that have been used and at the same time lock out the device for a period of time during which it will not accept the input from any switches. It is also within the scope of the present invention to incorporate other features in the system to enhance its security value. Thus, the system can incorporate circuitry to react to disconnection of the system from the vehicle electrical circuit or to provide circuits to react to other security sensors, for example to vibration detectors or heat detectors to sense movement of the vehicle or the presence of an intruder.

As will be appreciated from the above, when the system of the invention has been disarmed it will not disable or interfere with the operation of any of the circuits required for the proper operation of the vehicle. The vehicle can be therefore be operated in the conventional manner and the engine started and stopped in the normal manner until the system of the invention is armed. Since the arming stage requires a sequence of operations which would not normally be utilised during normal driving, the risk of accidental arming of the system is minimised. The vehicle can also be given to a third party for temporary use after which the system can be armed to render it secure. The disarming code is not required for this temporary use and its security is not affected. Moreover, if at any time the disarming code is disclosed, the system can readily be modified to permit alteration of the disarming code, for example merely by substituting the connection to the system from one control with that of another.

DESCRIPTION OF THE DRAWINGS: A particularly preferred form of the system of the invention and its operation will now be described by way of example with respect to the accompanying drawings in which Figure 1 is a circuit diagram for a device for use in the system.

DESCRIPTION OF A REFERRED EMBODIMENT OF THE INVENTION: The device consists of a solid state lock/unlock circuit, with provision for tamper sensing, and an output latching stage to drive two single switches controlling two essential circuits for starting the engine of the vehicle and keeping it running.

The main components of the device are shown in Fig. 1 and are the unlock sequencer 122, the output latch 123, the output relay coils 125 and 126, and contacts 127 and 128 for controlling respectively the operation of the vehicle ignition circuit and the starter motor solenoid circuit, and the tamper delay circuit 124.

When the vehicle ignition key switch is in the "Off" position and the device is armed, the switches and relay contacts will be in the positions shown in Fig. 1.

The device has terminals connected to external sources as follows: terminal 183 is connected to the positive pole of the vehicle battery and to terminal 134, terminal 182 is connected to the negative pole of the battery.

terminal 134 is connected to the first position on the ignition switch 135.

terminals 129 and 130 of relay 127 are connected in series with the vehicle ignition coil circuit.

terminals 131 and 132 of relayn 128 are connected in series with the starter solenoid circuit.

terminals 136, 137, 138, 139 and 140 are connected to the existing switches of the selected vehicle controls to be used in the arming and disarming operations and/or to extra "dummy" switches added to increase the number of controls available to be selected. Thus, terminal 136 is connected to the sidelight switch; terminal 137 is connected to the rear fog light switch; terminal 138 is connected to the second switch in a cluster of five extra switches fitted to extend the range of "disarming" switches. Further terminals 139 can be provided which are either dummy connections to confuse a thief or are connected to obstructing controls to extend the complexity of the disarming operation as described below.

Terminal 140 is connected to the "arming" control, which in this case is the switch controlling the reversing lights.

Terminals 136, 137, 138 and 139 have capacitors 160, 161, 162 and 163 connected to battery negative voltage to prevent switch bounce affecting the operation of the device.

The device is armed as follows: with the ignition switch in the "off" position, put the vehicle into reverse gear, thus actuating the reversing light switch; next, turn the ignition switch to the "on" position, wait for two seconds, and then turn the switch to the "off" position. The device is now "armed" and the solenoid switches 127 and 128 adopt the positions shown in Figure 1 preventing operation of the starter motor and the ignition circuit.

The method of starting the vehicle's engine by an authorized person after it has been "armed" is as follows:- First ensure that all switches are off and then switch the ignition switch to "on" position; secondly, momentarily switch on the first "disarming" switch, the side lights; thirdly, momentarily switch on the second "disarming" switch, the rear fog light; and fourthly momentarily switch on the third "disarming" switch, the switch of the cluster of five extra switches. These three momentarily operated switches must be in the "on" position for a time lapse of at least one second before they are switched off to satisfy the timing requirements of the circuit and to establish that they are valid operations of the switches.

These actions will cause an output from the sequence detector circuit 122 at terminal 170, resulting in an output being set in the latching circuit 123 at terminal 176. This output causes transistor 152 to conduct and allows current to flow in the relay coils 125 and 126 thus making contacts 127 and 128, allowing the starter solenoid coil and ignition coil circuits to operate normally, and allowing the engine to be started and kept running.

When the engine is stopped by turning the ignition switch to the "offal' position, the device "remembers" that is has been previously unlocked and will allow the engine to be started in the normal way by turning the key switch, unless the device has in the meantime been "armed".

If an unauthorized person tries to start the engine and switches on any of the unused "disarming" switches (except the those connected to terminal 139 as explained later) nothing would happen, and all relay contacts would remain as shown in Fig. 1. If on the other hand he switches on the rear fog light before the sidelights, the integrated circuit 122 would register a tamper pulse at terminal 169 which is connected to terminal 179 on the tamper circuit 124. An output now appears on terminal 180 of this circuit which charges capacitor 159 through resistor 157. When the reset threshold at terminal 181 is exceeded, terminal 180 returns to zero thus discharging capacitor 159 through diode 158.

This complete action has caused an output to appear at terminal 180 for a given length of time, and since terminal 180 is connected to terminal 168 (the sequence disable input) on the integrated circuit 122, no input sequence would have been accepted during that time even if it were a correct sequence. If the switch attached to terminal 139 is operated when attempting to input the disarming sequence, an output will immediately appear at terminal 169 and will disable the sequence detection circuit as above. This switch thus serves to obstruct the processing of any sequence by the device and it is necessary to begin the disarming sequence from the beginning once such an obstruction has occurred.

Therefore an unauthorized person not knowing which of the "disarming" switches to switch on and in which order they are to be switched on cannot start the engine of the motor vehicle even if he has the correct ignition key in his possession.

Claims

WHAT use CLAIM IS:

1. A security system for a vehicle, which system comprises an electrical circuit which is adapted to be connected into the electrical circuitry of the vehicle and which is adapted to be armed by receiving electrical signals from the operation of a series of the mechanical and/or electrical controls of the vehicle in a specified sequence and/or within a specified duration time span which system is adapted to actuate an alarm and/or to disconnect part or all of the electrical circuit of the vehicle required for operation of the vehicle if the specified sequence or duration for the input signals is not achieved during the arminy or disarming operations whereby the system can react to an unauthorised attempt to operate the vehicle, characterised in that the arming stage involves the actuation of at least one of the vehicle's controls which would not readily be actuated when the vehicle is in normal forward movement.

2. A system as claimed in claim 1 further characterised in that the disarming of the system requires the operation of a plurality of the controls of the vehicle in a predetermined sequence and within a specified time limit.

3. A system as claimed in any one of the preceding claims wherein the vehicle controls required to be actuated during the arming or disarming of the system include the engagement of reverse gear of the vehicle prior to actuation of the ignition circuit for the vehicle.

4. A system as claimed in any one of the preceding claims wherein the system requires the operation in specified order and for a specified duration time span of the the ignition switch and a fog lamp switch.

5. A system as claimed in any one of the preceding claims wherein the system is adapted to actuate an alarm if an attempt is made to start the engine of the vehicle, and to disable the ignition and/or starter motor circuits of the vehicle.

6. A system as claimed in any one of the preceding claims wherein the electrical connection between the circuitry of the system and the control which is to generate an input signal to the system is made directly to the control itself, to any point in the ciruit it controls or indirectly via a terminal block or other distribution means to which the control is connected electrically.

7. A system as claimed in any one of the preceding claims wherein the electrical connection between each vehicle control to be operated to arm and/or disarm the system and the circuit of the system incorporates a capacitor.

8. A system as claimed in any one of the preceding claims wherein the electrical circuit of the system incorporates a programmable memory means to contain the desired predetermined vehicle control operation sequence; and a timer circuit against which the timing of the operation of the controls is assessed.

9. A system as claimed in any one of the preceding claims provided a rechargeable battery adapted to operate the system and to be fed from the main battery of the vehicle.

10. A system as claimed in any one of the preceding claims wherein the circuit is adapted to receive input signals from one or more switches which do not have any function in the operation of the engine or other features of the vehicle.

11. A system as claimed in any one of the preceding claims wherein some of the vehicle controls are given the function of obstructing switches which if actuated will cancel out the effect of any correct switches that have already been actuated during the arming or disarming operation.

12. A system as claimed in any one of the preceding claims adapted to be operated in conjunction with a senso for detecting the presence of a person within a vehicle.

13. A system according to claim 1 substantially as hereinbefore described with respect to and as shown in the accompanying drawing.

14. A vehicle fitted with a security system as claimed in any one of the preceding claims connected to the electrical circuit of the vehicle so as to receive signals from a plurality of the controls of the vehicle to actuate its arming and disarming circuits during the arming and disarming operations.

15. A method for rendering secure a vehicle fitted with a system as claimed in claim 1, which method comprises arming the system by operating at least two of the controls of the vehicle in a sequence not normally used in the normal forward motion of the vehicle and disarming the system by the operation of a plurality of the controls of the vehicle in a predetermined sequence.

16. A method as claimed in claim 15, which method comprises arming the system by operating at least two of the controls of the vehicle in a sequence not normally used in the normal forward motion of the vehicle and disarming the system by the operation of a plurality of the controls of the vehicle in a predetermined sequence.

17. A method as claimed in either of claims 15 or 16 which requires the selection of the reverse gear of the vehicle before the ignition circuit is actuated.

18. A method as claimed in claim 15 substantially as hereinbefore described.