GB2313154A

GB2313154A - Vehicle immobiliser with mechanism acting on engine flywheel

Info

Publication number: GB2313154A
Application number: GB9609923A
Authority: GB
Inventors: Douglass Harrison
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-05-14
Filing date: 1996-05-14
Publication date: 1997-11-19
Anticipated expiration: 2016-05-14
Also published as: GB2313154B; GB9609923D0

Abstract

A mechanical immobiliser (9) is installed in a vehicle and is operable to prevent rotation of the vehicle engine (18), having a gearbox (19), by acting on the flywheel (11)in a flywheel housing (12). The mechanical immobiliser (9) is adapted to be maintained in, or brought into, operation by an unauthorised person sitting in the driver's seat (20), thereby depressing a pressure pad (1) causing the immobiliser (9) to remain in, or come into, operation together with an alarm siren (16) and an indicator lamp (17). A battery (14) provides electrical power, whilst a switch/touch pad (15) can override the immobiliser (9).

Description

VEHICLE IMMOBILISER The present invention relates to a vehicle immobiliser, and to a vehicle immobiliser system.

It is a problem today that many motor vehicles are entered in an unauthorised manner and driven away, without the owner's consent. Mainly this is a problem with automobiles which may be driven away more or less casually perhaps by younger people for the purpose of pleasure, or alternatively for the purpose of theft.

This problem is, of course, not restricted to automobiles, and larger vehicles such as lorries, perhaps carrying valuable cargoes, can also be targets for thieves.

There have been many suggestions for providing alarm systems to indicate vehicle theft, and also immobiliser systems have been proposed also. An alarm system may cause a vehicle to emit a loud warning noise when the vehicle is tampered-with, or an immobiliser system may cause the electrical system of the vehicle to be rendered inoperative to prevent the engine of the vehicle being started.

In general, such systems are applied to the electrical system of the vehicle only, and involve an electrical path through the ignition switch of the vehicle. A skilled thief can often make an electrical connection across the ignition switch of a vehicle without actually using the authorised ignition key, and can in this way often by-pass the types of alarm and/or immobiliser systems presently in general use.

According to one aspect of the present invention there is provided a mechanical immobiliser which prevents rotation of the vehicle engine, which immobiliser will be maintained in, or brought into, operation by an unauthorised person.

Preferably, the immobiliser comprises a solenoid which in one condition will prevent the engine from rotating, the solenoid preferably being mechanically coupled to a locking block which, when in a predetermined position, will obstruct rotation of the engine.

A preferred method of preventing rotation of the engine is to prevent rotation of the flywheel of the engine, possibly employing a ring gear mounted on the flywheel.

Accordingly, the locking block may cooperate with the ring gear to prevent rotation of the flywheel and the engine, and the locking block may be formed with teeth which mesh with teeth of the ring gear.

Alternatively, rotation of the engine may be prevented by preventing rotation of any other suitable moving part of the engine employing a ring gear.

According to another aspect of the present invention, a vehicle immobiliser system comprises a switching mechanism arranged to be operated by an unauthorised person, which switching mechanism maintains in, or brings into, operation a mechanical immobiliser.

Preferably, an authorised person will be able to override the immobiliser system switching mechanism, possibly by operating a master switch which is either hidden in a location which will be known only to an authorised person, or which is operable only by means of a code which will be known only to the authorised person.

The switching mechanism may be coupled to or contained in a seat of the vehicle such as the driver's seat, so that when an unauthorised person sits in that seat the immobiliser is kept in or comes into operation.

The switching mechanism may comprise a pressure pad which will be depressed by a person in the vehicle, for example sitting in the driver's seat, and which will activate a pressure switch to operate the immobiliser or keep it in operation.

A particularly advantageous embodiment of the present invention will combine an immobiliser as described which will prevent the engine flywheel from rotating, together with a switching mechanism, for a solenoid, built into a seat of the vehicle.

For a better understanding of the present invention and to show how it may be put into effect reference will now be made, by way of example, to the accompanying drawings in which: Figure 1 shows a preferred embodiment of switching mechanism which can operate a mechanical vehicle immobiliser; Figure 2 shows a preferred embodiment of a mechanical immobiliser which can be operated by the switching mechanism of Figure 1; Figure 3 shows a terminal block comprising terminal connections to various components of an immobiliser system; Figure 4 is a circuit diagram of the immobiliser system as connected to the terminal block of Figure 3; Figure 5 shows a typical arrangement of an immobiliser system in a saloon automobile; and Figure 6 shows a typical arrangement of an immobiliser system in a cab forward lorry/tractor unit.

Figure 1 shows a switching mechanism of an immobiliser system, which is built-into the driver's seat of a vehicle such as an automobile or a lorry.

A pressure pad 1 which is square-shaped in plan view is coupled through four spring loaded guideposts 2, at the four corners of the pressure pad 1, to an activation plate 3 which extends in a plane parallel to that'of the pressure pad 1. The assembly of pressure pad 1, spring loaded guideposts 2 and activation plate 3 can move up and down as indicated by the paired arrows in Figure 1, with the assembly being spring loaded in the upwards direction.

The spring loaded guideposts 2 extend through corresponding holes in the upper wall of a control housing 5, with the activation plate 3 resting on an end of an actuating arm of a pressure switch 4. The activation plate 3 is shown in its upper position in Figure 1, into which upper position it is spring loaded.

The lower wall of the control housing 5 contains a power-in jackpoint 6, through which electrical connections can be extended to the pressure switch 4.

When the switching mechanism of Figure 1 is installed in a vehicle seat, the so-called "hot seat", a person sitting on the seat will exert downwards pressure on the pressure pad 1, causing the spring loaded guideposts 2 and the activation plate 3 to travel downwards also. The downwardly-moving activation plate 3 will accordingly cause the operating arm of the pressure switch 4 to move downwardly also, thereby changing the electrical state of the pressure switch 4.

Figure 2 shows a mechanical immobiliser according to a preferred embodiment of the present invention.

Briefly, a flywheel 7 of a vehicle engine can be prevented from rotating by a locking block 8 which can be moved radially inwardly and outwardly by a solenoid 9 with respect to the rotational axis 10 of the flywheel 7.

The flywheel 7 has a ring gear 11 extending around an edge of the flywheel 7, the ring gear 11 comprising a series of gear teeth as shown. The radially inner surface of the locking block 8 also is provided with a series of teeth, which can mesh with the teeth of the ring gear 11. When the locking block 8 is in a forwards position, the teeth of the locking block 8 and of the ring gear 11 mesh, thereby preventing rotation of the flywheel 7 and of the remainder of the vehicle engine. In this situation, the vehicle engine cannot be started by the starter motor (not shown) which is arranged to rotate the flywheel 7 by a pinion engaging with the ring gear 11.

The flywheel 7 with its ring gear 11 are contained within a circular housing 12, whilst the solenoid 9 is mounted on a smaller housing 13 having an inner space allowing the locking block 8 to be withdrawn away from the flywheel 7 into a position where the teeth of the locking block 8 and of the ring gear 11 no longer mesh, so that the flywheel 7 can rotate as normal with the remainder of the vehicle engine.

The circumferential edges of the flywheel housing 12 and the adjacent edges of the rocking block housing 13 are securely connected together, preferably by welding. Alternatively, the two housings 12 and 13 may be integrally formed into a single housing structure.

Figure 3 shows a terminal block or power box providing various electrical connections between a power source, an alarm, an immobiliser such as the solenoid 9 of Figure 2, an indicator lamp, a switch such as the pressure switch 4 of Figure 1, and earth.

Reference numerals 1 to 10 are given to the terminals of the terminal block, and it is indicated which terminals are connected to which of the various listed devices.

It is to be noted that in each pair of terminals for each device, the two terminals are not directly next to one another along the terminal block, but are at random positions along the terminal block. This makes it extremely difficult for a person who locates the terminal block, to disturb the connections to any one particular device.

Figure 4 shows a circuit diagram wherein the numbered terminals of Figure 3 are shown in circles. A DC power source 14 (which may be the vehicle battery) is shown connected in series with a master switch 15 and the pressure switch 4 of Figure 1, whilst there are connected in parallel with that series connection, an alarm 16 such as a siren, the solenoid 9 of Figure 2, and an indication lamp 17.

In normal circumstances when the vehicle is left standing, the pressure pad of Figure 1 is in an upper position with pressure switch 4 open, and with the solenoid 9 of Figure 2 de-energised with the locking block 8 being disengaged from the ring gear 11. In this situation, the master switch 15 is closed as shown in Figure 4.

When the owner or other authorised person wishes to drive the car, before sitting in the seat to which is coupled the switching mechanism of Figure 1, he or she must first open the master switch 15. This master switch 15 may be for example a key-operated switch to which only an authorised person has a key, or it may be a rocker switch hidden on the body or in the interior of the vehicle, perhaps in the boot. Alternatively, a digital touch pad on the dashboard may be involved, programmed with a code known only to an authorised person.

When the master switch 15 has been opened, the authorised person may then sit in the seat coupled to the switching mechanism of Figure 1. Thus although the pressure switch 4 in Figure 4 then closes, the connection from the DC power source 14 to the alarm 16, solenoid 9 and indicator lamp 17 remains broken by the opened master switch 15. The solenoid 9 remains deenergised, the locking block 8 remains disengaged from the ring gear 11, and the vehicle engine can be started as usual.

On the other hand, if the vehicle is entered by an unauthorised person who does not open the master switch 15, immediately he sits down in the seat coupled to the switching mechanism of Figure 1, the pressure pad 1 is depressed, leading to the activation plate 3 operating the pressure switch 4. As a result, the alarm 16, solenoid 9, and indicator lamp 17 all become energised by the DC power source 14.

As a result, the alarm 16 sounds, the indicator lamp 17 becomes illuminated, and in Figure 2 the energised solenoid 9 drives the locking block 8 forwards so that its teeth engage with the teeth of the ring gear 11 on the flywheel 7. The flywheel 7 cannot rotate, the remainder of the engine cannot rotate, and the vehicle cannot be started. The alarm 16 should preferably be fitted with a time delay function to activate a siren approximately 30 seconds after the system has been triggered. The immobiliser solenoid 9 should operate as soon as the system is triggered.

Preferably, the circuitry of Figure 4 involves no connection through the ignition switch of the vehicle, so that even if an unauthorised person makes an electrical connection across the ignition switch, or even operates the ignition switch with a stolen key, then the circuit of Figure 4 cannot be prevented from becoming energised.

Also preferably, the pressure switch 4 is adapted to remain in a closed position even if the activation plate raises by means of an unauthorised person subsequently rising from the driver's seat when he realises that the vehicle cannot be started. In this way the various security devices including the solenoid 9 can remain energised until the master switch 15 is eventually opened by an authorised person.

Figures 5 and 6 show typical arrangements of a "hot seat" immobiliser system in a saloon automobile and in a cab forward lorry/tractor unit respectively.

These figures are self explanatory, and show how an immobiliser system as hereinbefore illustrated and described can be installed with respect to the engine 18, flywheel housing 12 and gearbox 19 of a vehicle, employing the driver's seat 20 as "hot seat", and with the immobiliser system being powered by the vehicle battery 14.

It will be appreciated that the invention is not restricted to the particularly illustrated and described devices. For example, the switching mechanism of Figure 1 may be replaced by some other suitable switching mechanism, which may perhaps be located differently than in the driver's seat of the vehicle. For example, the switching mechanism may be coupled to the vehicle door, to energise the various security devices if the door is opened before a master switch located on the exterior of the vehicle, or in the boot of the vehicle, is opened.

The immobiliser of Figure 2 may also be replaced or modified in accordance with some other mechanism suitable mechanically to immobilise the engine of the vehicle, whilst in Figures 3 and 4 one or both of the alarm 16 and indicator lamp 17 may be omitted.

Other modifications and changes within the scope of the invention will also be apparent to a man skilled in the art. For example, in the described embodiment the immobiliser of Figure 2 is brought into operation by an unauthorised person operating the switching mechanism of Figure 1. Alternatively, when the vehicle is left unoccupied the circuit of Figure 4 could be modified to keep the immobiliser in operation until an authorised person deactivates it. Thus the unauthorised person would keep the immobiliser operative, whereas the authorised person could render it inoperative.

Claims

CLAIMS:

1. A mechanical immobiliser installed in a vehicle and operable to prevent rotation of an engine of the vehicle, the mechanical immobiliser being adapted to be maintained in, or brought into, operation by an unauthorised person.

2. A mechanical immobiliser according to claim 1, and comprising a solenoid which in one condition of energisation will prevent the engine from rotating.

3. A mechanical immobiliser according to claim 1 or 2, and comprising a locking member which, when in a predetermined position, will obstruct rotation of the engine.

4. A mechanical immobiliser according to any one of the preceding claims, and which is arranged to act on a flywheel of the engine.

5. A mechanical immobiliser according to any one of the preceding claims, and which is arranged to act on a ring gear of the engine.

6. A mechanical immobiliser according to claims 4 and 5 combined, and wherein the ring gear is on the flywheel.

7. A mechanical immobiliser according to claim 4 when appended to claim 3, or claim 6 when claim 4 is appended to claim 3, wherein the locking member is housed in a locking member housing connected to or integral with a housing of the flywheel.

8. A mechanical immobiliser according to claim 5, 6 or 7, when appended directly or indirectly to claim 3, wherein the locking member comprises teeth to mesh with the teeth of the ring gear.

9. A mechanical immobiliser according to any one of the preceding claims, which is adapted to be maintained in, or brought into, operation by means of a switching mechanism which is adapted to be operated by an unauthorised person.

10. A mechanical immobiliser according to claim 9, wherein the switching mechanism is coupled to or contained in a seat of the vehicle.

11. A mechanical immobiliser according to claim 9 or 10, wherein the switching mechanism comprises a pressure pad which will be depressed by a person in the vehicle.

12. A mechanical immobiliser according to any one of claims 9 to 11, wherein the switching mechanism involves no electrical connection through an ignition switch of the vehicle.

13. A vehicle immobiliser system comprising a switching mechanism arranged to be operated by an unauthorised person, which switching mechanism is arranged to maintain in, or bring into, operation a mechanical immobiliser.

14. A vehicle immobiliser system according to claim 13, wherein the switching mechanism is coupled to or contained in a seat of the vehicle.

15. A vehicle immobiliser system according to claim 14, wherein the switching mechanism comprises a pressure pad which will be depressed by a person in the vehicle.

16. A vehicle immobiliser system according to claims 13, 14 or 15, wherein the switching mechanism involves no electrical connection through an ignition switch of the vehicle.

17. A vehicle immobiliser or system according to any one of the preceding claims, which has an override facility.

18. A vehicle immobiliser or system according to claim 17, wherein the mechanical immobiliser, once brought into operation, is adapted to remain in operation until the override facility is brought into operation.

19. A vehicle immobiliser or system according to any one of the preceding claims, which is arranged to bring into operation an audible alarm and/or an indication lamp when operated by an unauthorised person.

20. A vehicle immobiliser which is mechanical in operation to prevent rotation of an engine of the vehicle, and which is arranged to act on a flywheel of the engine.

21. A vehicle immobiliser according to claim 20, and comprising a locking member which, when in a predetermined position, will obstruct rotation of the flywheel.

22. A vehicle immobiliser according to claim 21, wherein the locking member is adapted to act on a ring gear of the flywheel.

23. A vehicle immobiliser according to claim 22, wherein the locking member comprises teeth to mesh with the teeth of the ring gear.

24. A vehicle immobiliser according to any one of claims 21 to 23, wherein the locking member is housed in a locking member housing connected to or integral with a housing of the flywheel.

25. A vehicle immobiliser according to any one of claims 20 to 24, and comprising a solenoid which in one condition of energisation will prevent the flywheel from rotating.

26. A mechanical immobiliser according to claim 1 and substantially as hereinbefore described with reference to Figure 2 of the accompanying drawings.

27. A vehicle immobiliser system according to claim 13 and substantially as hereinbefore described with reference to Figures 1 to 4 of the accompanying drawings.

28. A vehicle immobiliser system according to claim 27 and further substantially as hereinbefore described with reference to Figure 5 or 6 of the accompanying drawings.

29. A vehicle immobiliser according to claim 20 and substantially as hereinbefore described with reference to Figure 2 of the accompanying drawings.