ANTI-THEFT AUTO-LOCK

Abstract: An anti-theft auto-lock which comprises a key switch (1) locatable adjacent to the controls of a motor vehicle; a cylinder (5) locatable adjacent to the engine block of the motor vehicle; a piston (6) moveable within the cylinder and a conduit (4) extending between the cylinder and a security shell enclosing the key switch (1). The conduit (4) and cylinder (5) contain means for reciprocally moving the piston (6) through a predetermined distance within the cylinder (5). A restoring spring (7) for piston (6) is accommodated within the cylinder (5). Also a micro-switch (13A) means is associated with the piston and cylinder assembly and is electrically incorporated in the motor vehicle's ignition circuit.

Description: - 1 - ANTI-THEFT AUTO-LOCK This invention relates to locking systems, and more particularly to means for protecting motor vehicles against theft or unauthorised use. Various methods have been employed to immobilise motor vehicles, apart from the ordinary system of locking the ignition circuit whereby the authorised user simply uses a key to operate a lock which normally closes a switch in that circuit. Such methods have usually been designed to defeat a thief who normally attempts to overcome a closed ignition switch by simply bridging the terminals of that switch by so-called "hot wiring" or the like. These expedients have depended upon (a) the detection of voltage changes in door light circuits or the like, resulting from unauthorised tampering, to operate an- alarm, or (b) the detection of vehicle movement during such tampering. However system (a) suffers from the disadvantage that a mere disconnection of the battery will quickly extinguish the alarm, whereas system (b) has the additional disadvantage that, if made sufficiently sensitive to respond to unauthorised interference with a vehicle, the alarm may be falsely operated by extraneous factors such as wind gusts or unskilled parking which can rock the vehicle. A further disadvantage of both systems is that the sound of any such alarm is most likely to be ignored by strangers, motivated either by indifference or cynicism, or a sincere belief that yet another malfunctioning system is emitting a false alarm. It is an object of the present invention to overcome the above and other disadvantages and to provide an anti-theft locking system which will even defeat a thief who is fully aware of the manner in which it operates. Therefore, in accordance with the present invention, an anti-theft auto-lock comprises a key-switch locatable adjacent the controls of a motor vehicle; a cylinder locatable adjacent the engine block of said - 2 - motor vehicle; a piston movable within said cylinder; and_ a conduit extending between said cylinder and a security shell enclosing said key-switch; said conduit and cylinder..containing means for..reciprocally moving said piston through a pre-determined distance within said cylinder; a restoring spring for said piston, accommodated within said cylinder, and micro-switch means associated with said piston-and-cylinder assembly, said micro-switch means being electrically incorporated in said motor vehicle's ignition circuit in such a wa that, --.,.- when said means for reciprocally moving said piston ceases to be operative by reason of undesirable interference therewith, said restoring spring is returned to its rest position, thereby moving said piston so as to actuate said micro-switch means in such a way as to render said ignition circuit inoperative. Ideally, the means for reciprocally moving the piston within its cylinder is a vacuum, a though other means are nevertheless envisaged, such as hydraulic fluid or compressed air, or even mechanical means such as a Bowden cable or other filament having pre-set tension. The key-switch moves this filament to complete the ignition circuit, the arrangement being such that, if the filament is severed unlawfully, said filament rotates back to a rest position in which the micro-switch is actuated in such a way as to render the ignition circuit inoperable. In a particularly preferred embodiment, the piston-and-cylinder assembly and associated components are mountable within a casing adapted to enclose the distributor of the engine. In order that the reader may gain a better understanding of the present invention, hereinafter will be described a preferred embodiment thereof, by way of example only, and with reference to the accompanying drawings in which:- Fig. 1 is a somewhat schematic vertical cross-section through a key-switch and security shell according to the present invention; - 3 - Fig. 2 is a somewhat schematic vertical cross-section through a cylinder-and-piston assembly, in a "vacuum-held" mode; Fig. 3 is a corresponding view, but in a 5 "vacuum-released" mode; Fig. 4 shows how a cylinder-and-piston assembly may be mounted within a distributor casing; Fig. 5 is a perspective view of a distributor security cover; 1.0 . Fig..6 illustrates an alternative, mounting means for a cylinder-and-piston assembly; and Fig. 7 is a cross-section corresponding to Fig. 6. Throughout the drawings, similar references indicate corresponding parts. 15 Referring first to Figs. 1 to 3, the inventive anti-theft auto-lock will be seen to comprise a key-switch 1 which may well be a substantially standard ignition circuit key-switch and is ideally locatable adjacent the controls of a motor vehicle, perhaps in some 20 convenient position on or near the vehicle's instrument panel. Key-switch 1 is enclosed within a security shell 2 the purpose of which will be revealed hereinafter, and has extending therefrom a flexible conduit or hose 4 the 25 other end of which is in communication with a piston-and-cylinder assembly - to be seen in Figs. 2 and 3. This assembly consists in a cylinder 5 in which is a reciprocally movable piston or plunger 6; conduit 4 is sealed to the cylinder housing 13 in vacuum-tight 30 manner. Cylinder 5 also has, accommodated therewithin, a helical restoring spring 7 for piston 6. Within the barrel or cylinder 5 of housing 13 there is a terminal block 11 which electrically connects, via wires or cables 9, 10, with a similar terminal block 8 35 within the security shell 2 enclosing key-switch 1, and which is electrically incorporated into the motor vehicle's ignition circuitry. Wires 9 and 10 are sealed into an end-wall 12 of conduit 4 so as to render the communicating interiors of conduit 4 and cylinder housing - 4 - 13 vacuum-tight and to prevent easy disconnection of security shell 2 and conduit 4 - with resulting exposure of terminal block 8 - by virtue of the annular flange 12A. The electrical elements of the invention are incorporated in the vehicle's ignition circuit, as stated, and the conduit and cylinder interiors are placed under vacuum so that the piston 6 is "sucked" towards tne key-switch end of the cylinder to thus compress spring 7 and prevent air from entering the system through the inlet 12B.... In this "vacuum held" position, as shown in Figure 2, the ingnition key-switch can be used in the normal way but it is not possible to unlawfully start the motor vehicle by such means as bridging the terminals, or "hot wiring". In order to do so, a would-be thief would have to gain access to the wiring system but this is denied to him by virtue of the fact that the circuitry becomes inoperative upon any attempt to gain this access. A would-be thief then, attempting to tamper with the conduit 4, as say by cutting it, will merely admit air into the system. When this occurs, the compression spring 7 will relax to its rest position and propel piston 6 towards the end of cylinder 5, to press a contact button of a micro-switch 13A which cuts off the power to the ignition circuit of the vehicle and so renders it useless to a person wishing to "bridge" it in any way. The helical restoring spring is concealed within cylinder housing 13 and hense an observer cannot detect the nature or magnitude of its movement. Similarly, if any attempt is made to compensate for the "suction" effect within the conduit or hose 4 by, say, forming a pinhole in its outer surface in order to admit air thereto, such an action is fraught with difficulty since it is not only necessary to admit precisely the right amount of air to cause the requisite movement of the piston to actuate the switch means but also to immediately thereafter seal the hole made by any invading instrument, and the great delicacy of any such action is out of the question when it is remembered that the designed movement of the piston is of the order of 20mm or thereabouts. Because of the nature of the invention, there is no necessity to hide the system in any way, and it is of little consequence where the key-switch and cylinder are •5 •• * " -located. ■*■* - • - * * ' ■ • .* -- ■• • .. • . ' However, some simplification will result if the "key" is in fact the standard ignition key. Thus the ignition lock may simply be provided with a pair of extra contacts located in the inhibiting circuit. Although a 10 standard ignition lock, may be modified in this manner it is less complex to provide a separate add-on installation, especially since theft-proof devices are largely supplied as an after-market item for vehicles. Alternatively, the "key" may be the only key, being used 15 solely for the purpose of opening and closing the inhibiting circuit, whereas the ignition circuit may simply be opened and closed in known manner by an ordinary switch, as in some military or farm vehicles. For reasons of convenience, it is preferable that 20 the piston-and-cylinder assembly and its associated components should be mounted adjacent the distributor of the vehicle's engine. Referring now to Figs. 4 and 5, a suitable casing 14 for this purpose may be cast in two halves which overlap, as at 15, the two halves being 25 securable firmly together by a so-called "cam lock" 16. Such a casing as 14 may be cast from, say, aluminium or one of its alloys and may have a thickness of the order of perhaps 1.25mm. Suitable bolts may be used to fasten the casing 14 over a standard distributor 17 - shown in 30 chain line in Fig. 4 - to the usual mounting therefor, so that all that emerges from the casing 14 is the flexible conduit or hose 4 - extending through the grommet 18 - leaving the rest of the distributor 17 covered. The neat appearance of the engine installation is thus not 35 seriously altered, since one extra conduit disposed thereabout is of little consequence. Nevertheless, the appearance of the installation is not meant to be part of any deterrent. Even if the inventor were to explain to the thief how the invention - 6 - is employed, the latter could still not defeat it since he has only two choices, namely (1) to interfere with the conduit - and thus admit air thereto, or (2) to approach the engine and smash the system which he observes built around the distributor, but in so doing he renders the engine useless and cannot start it, unless perhaps he brings along another distributor and is prepared to carry out some re-timing of the engine, possibly in a public place and under observation, and using -e-'ither guess-work or cumbersome test equipment. In any case, if suitably strong bolts are used to hold the distributor casing down over the usual supporting flange, the protection against "smashing" can be quite adequate. It will now be clear that a constant vacuum needs to be maintained within the conduit and cylinder, and to this end it should be stated that, in the initial assembly of the inventive device, security shell 2 is slipped over the conduit 4 from its distributor end before the latter is installed, but after wires 9 and 10 are connected to terminal block 8 of key-switch 1 via the sealing flanged end 12 of conduit 4. When the security shell 2 is in position it is permanently keyed to the body of the key-switch 1 by means of a steel pin 23 inserted through a bore in security shell 2 and on into key-switch 1, as indicated at 24 in Fig. 1. Referring once again to Figs. 2 and 3, the system is "charged" with the vacuum by a source of suction being applied to a one-way ball-valve 25 situated in the wall of the cylinder housing 13. Various modifications of the invention are contemplated although not illustrated in every case. For example, a flexible helically-coiled spring wire may be located coaxially in the conduit. When such a conduit is squeezed the thief has even less control over the manipulation of the vacuum than if a large-sectioned conduit were employed. Thus it would be likely to require even greater delicacy of control to defeat the system. A further reason for using such a spring wire insert is to make the system even more reliable. Because - 7 - of the vacuum obtaining in the conduit, it may be that under sufficiently hot conditions the conduit would at least partially collapse inwardly upon itself, and such action is of course, prevented b haying, solid insert which acts as an internal support. In this connection, the cross-section available within the conduit for retaining the vacuum is interdependent upon the strength of the restoring spring 7. If the spring is very strong, then an ordinary conduit will suffice, such as a simple plastic tube of. the kind used in engines for other purposes, such as fuel lines. However, although a strong spring may well be employed, it should not be so strong that the system is difficult to set up and calibrate so as to achieve just the right cut-off point for the switch. In this connection, it is of course desirable that the whole unit should be made in a factory with the pre-set "thow" from the "vacuum held" position consistent at all times. In a further modification, the spring wire insert located inside the conduit 4 could itself be that which carries the ignition current, instead of those referenced 9 and 10 in Figs. 1 to 3. Hence if the conduit is ever maliciously severed, no purpose would be served by attempting to join the wire ends together. Referring now to Figs. 6 and 7 of the drawings, these show an alternative to the distributor casing 14 of Figs. 4 and 5. This comprises a protective plate 19 having a cylinder-housing-enclosing arcuate portion 20 and wells 21 adapted to receive key-operated locking nuts designed to secure the housing - shown in chain line - to an engine block 22. In order to make the system attractive for after-market buyers it is desirable of course that at least a limited range of said distributor housings should be provided, suitable for the more popular vehicles such as Holdens, Falcons, Datsuns and the like. It will be seen that the system provided by the invention is one of great simplicity, since to arm the system it is merely necessary before leaving the vehicle - 8 - to turn a key and then forget about it. It is not even necessary to close the windows. Likewise, it is just as easy to re-activate the system by turning the same key in .......... the,.ppposite..,directi n--... Furthermore,, contrary.to", many .. .. 5 existing systems which are adequate perhaps for stopping a thief who does not have much time for his nefarious activities, the present invention will be just as effective against a thief with adequate time at his disposal. 10. Because the- system is so easily armed it is likel to be always used, contrary to such crude methods of disabling vehicles as using dummy ignition wires, removing plugs or crossing plug leads, such methods requiring the driver to go to the trouble to get out and 15 lift the hood every time he leaves his vehicle, sometimes by operating in the dark and in an atmosphere of grease and dirt. Another great advantage of the invention is that the vacuum within the conduit puts the would-be thief in 20 great difficulties. However, in those embodiments using hydraulic fluid or compressed air, wherein some fluid is lost when the system is broached, it might be just possible to judge how much fluid should be extracted when tampering with a subsequent vehicle, although it would be 25 too late to rectify one's mistake with the one presently being tampered with. But where air is sucked in when the conduit is broached, it is not possible for even an acute observer to judge how much has thus been admitted, so that even if the thief does not succeed with his first 30 attempt on one vehicle it does not help him when he makes a further attempt on a subsequent vehicle similarly equipped. Although the invention has been described herein with respect to vehicle protection, it could also be used 35 for buildings and the like because of the fact that negative pressure is the same at any point along the length of the conduit (contrary to the inevitable voltage-drop along lengthy alarm wires) and hence the actual length of the conduit has no effect upon the - 9 - sensitivity of the system, which could thus be placed all. the way around the interior of a building which it may be desired to protect against unauthorised entry, using a suitable inhibiting system.as above described. From the above, it will be appreciated that anti-theft auto-lock devices made in accordance with the present invention will provide the public with a new or much-improved article or, at the. very least, offer to it a useful and attractive choice.

Claims: - 10 - THE CLAIMS ; 1. An anti-theft auto-lock comprising a key-switch (as hereinbefore defined) locatable adjacent the controls of a motor vehicle; a cylinder locatable adjacent the engine block of said motor vehicle; a piston movable within said cylinder; and a conduit extending between said cylinder and a security shell enclosing said key-switch; said conduit and cylinder containing means for reciprocally moving said piston through a predertermined distance within said cylinder.;, a.restoring spring for said piston, . accommodated within said cylinder, and micro-switch means associated with said piston-and-cylinder assembly, said micro-switch means being electrically incorporated in said motor vehicle's ignition circuit in such a way that, when said means for reciprocally moving said piston ceases to be operative by reason of undesirable interference therewith, said restoring spring is returned to its rest position, thereby moving said piston so as to actuate said micro-switch means in such a way as to render said ignition circuit inoperative. 2. The anti-theft auto-lock as claimed in Claim 1, wherein said moving means contained within said conduit and cylinder is a vacuum. 3. The anti-theft auto-lock as claimed in Claim 1 or Claim 2, wherein said piston-and-cylinder assembly is mountable within a casing adapted to enclose the distributor of said motor vehicle's engine. 4. The anti-theft auto-lock as claimed in any one of the preceding claims, wherein said micro-switch means is actuable by a current of a magnitude less than that required by said motor vehicle's ignition circuit. 5. An anti-theft auto-lock, substantially as hereinbefore described with reference to the accompanying drawings.

Inventors: PREDDY BRIAN FRANCIS, PREDDY, BRIAN, FRANCIS
Applicants: AUSTCORP NO 107 PTY LTD, CLARKE BRIAN GEORGE, AUSTCORP (NO. 107) PTY LTD., CLARKE, BRIAN, GEORGE
Application year: 1985
Main classification: B60R25
IPC codes: B60R25