WO1989009149A1

WO1989009149A1 - Improvements relating to anti-theft automobile steering security systems

Info

Publication number: WO1989009149A1
Application number: PCT/AU1989/000127
Authority: WO
Inventors: Francis Warwick Deuchar
Original assignee: Francis Warwick Deuchar
Priority date: 1988-03-29
Filing date: 1989-03-29
Publication date: 1989-10-05

Abstract

An anti-theft locking device for an automobile steering shaft (21) encased in a housing (24) comprises an abutment member (22) interengageable with a movable detent member (25) mounted adjacent the abutment member, the detent (25) movable between an engaging and disengaging position. In the engaging position the detent member (25) prevents rotation of the steering shaft (21) and any forces applied to the detent member (25) by forced movement of the steering shaft (21) are transmitted to the housing (24). A slipping clutch arrangement allows relative movement of the shaft and housing with application of high pressure so as to prevent breakage of components. The locking device has a two-part rotatable locking barrel (12, 13) mounted in a lock housing (10, 19) and adapted to operate an ignition switch. Unauthorised rotation of one barrel is ineffective in operating the switch and lock mechanism. An alternative arrangement includes an actuating device engageable with a locking pawl the arrangement being such that unauthorised tampering with the ignition lock renders the pawl actuating device inoperable and inaccessible.

Description

IMPROVEMENTS RELATING TO ANTI-THEFT AUTOMOBILE STEERING

SECURITY SYSTEMS FIELD OF THE INVENTION

This invention relates to anti-theft steering c security systems useful for the prevention of unauthorised use of a motor vehicle by rendering the steering mechanism inoperative. BACKGROUND OF THE INVENTION

Conventional systems known to Applicants embody _1Q locking devices associated with the ignition key cylinder and including a bolt capable of locking the steering shaft against movement. Such a type is disclosed in Australian Specification Nos. 513,206 and 517,092.

In my earlier Application No. PCT AU85/00236 there _{l t}- are disclosed arrangements which electrically lock or unlock the steering column relative to the steering mechanism.

This problem has also been addressed in U.S. Specification Nos. 3,566,633 and 3,566,634 assigned to Borg-Warner Corporation wherein in the first mentioned ₂₀ specification a steering column lock incorporates a

"break-away torque" to prevent or minimise the breakage of components in the steering lock and yet render it impossible to control the vehicle whilst in motion under normal circumstances. -_c The second mentioned specification provides that the steering wheel and upper portion of the steering column will free the wheel with respect to the lower portion of the column and steering linkage. This specification addresses the problem of component damage and easy forcing of the ,_n conventional locking mechanism by utilising mechanical components capable of effecting disengagement of the steering wheel from the steering linkage and therefore preventing effective steering of the vehicle.

Applicant is not aware of any public or private use ,,- whatsoever of the apparatus disclosed in the abovementioned U.S. specifications. Applicant is also aware of Australian Patent Specification No. 34790/84 based upon a Spanish application. This specification was published in Australia after the earliest filing date of my application, however, the disclosure therein relates to mechanical componentry to provide for disengagement of the steering column link between the steering wheel and the steering linkage. In each instance the disengagement and engagement is performed mechanically and requires the proximity of the ignition switch to the lock to allow direct mechanical interaction between the ignition switch and the steering column lock. Applicant is also aware of prior art specifications mentioned in the International and European Search Report of my earlier referred to patent application including French published specification No. 2,085,222 disclosing an electrically actuated fail-safe component. French specification No. 2,432,408 discloses an inaccessible free wheeling clutch on the steering shaft.

A further aspect of the prior art ignition lock systems provide for key locking devices mounted on the steering column and operated by a key or like device which is adapted to simultaneously actuate and de-actuate the steering lock mechanism and the electrical ignition system of a motor vehicle. The key locking device constitutes a further possibility for unauthorised actuation of the system simply by forcing a screwdriver or like implement into the key slot and forcing it to turn. It is known to Applicant that this particular method represents a common way of forcing entry to the steering and ignition lock system.

There have been many attempts at securing the key barrel lock against forced entry and by way of example, I refer to U.S. Patent Specification Nos. 4,104,898 which utilises a rotatable blocking diaphragm between the key opening and the operating portion of the lock; No. 4,357,815 which discloses an anti-theft centralised latching system; No. 4,386,510 which utilises a key changeable lock core; No. 3,999,413 is of similar type allowing resetting to receive a different key; and No. 1,505,865 which discloses a lock release element adjustably connected with the locked barrel. Another method of forcing the lock is simply to remove the barrel thus exposing the internal components of the lock for easy actuation. U.S. Patent Specification No.

3,319,867 discloses a method of retaining the barrel against forced removal.

French published specification number 2,541, 344/A discloses a split lock barrel comprising a fixed and a movable part operable by a perforated card to move spring biased longitudinally disposed rods in the barrel to a junction between the fixed and movable parts of the barrel to allow release of the lock mechanism.

SUMMARY OF THE PRESENT INVENTION

The present invention has as one of its objectives the provision of a split or dual lock barrel which is extremely difficult, if not impossible, to force and to pick.

Whilst the prevention of damage to componentry by unauthorised use is an important feature, the present invention sets out to overcome a further problem, namely, the relatively complex and expensive construction of prior art locking devices.

The present invention has as its objective the provision of an anti-theft device which is equally adaptable either as original equipment to motor vehicles or as a replacement part to existing automotive steering locks at least on the more popular makes of motor cars currently used in Australia and many other countries, as manufactured for example by the Ford Motor Company and General Motors

Corporation.

A further objective of the invention is to endeavour to avoid disadvantages with conventional ignition key locking mechanisms in providing an ignition key locking mechanism wherein extraction of the barrels from their housing can be made difficult, if not impossible.

Alternatively, if it is possible or even relatively easy to remove the barrel or barrels it is important that the mechanism remaining is inoperable. There is provided according to the present invention a vehicle anti-theft steering lock device for fitment to a steering shaft, the device having a locking pawl selectively operative with the shaft to prevent _c rotation of the shaft, including clutch means adapted to be mounted between said steering shaft and said locking pawl and selectively engagable with said locking pawl, said clutch means including resilient spring means for creating a torque against relative movement of the shaft and the clutch

₁₀ means but allowing relative movement upon application of a predetermined turning force, said force being sufficient to prevent normal operation of the steering shaft.

There is also provided according to the present invention in a vehicle key ignition lock for operating a

_,,- pawl on a steering lock mechanism, comprising actuating means operably engagable with said pawl to operate said steering lock mechanism upon operation of said key ignition lock, wherein said actuating means is so mounted relative to said ignition lock that unauthorised tampering with said

₂₀ lock renders said actuating means inoperable and inaccessible.

There is provided according to the present invention, an anti-theft locking device for an automobile including a steering shaft encased in a housing, said shaft

_j- connecting a steering wheel to the steering mechanism of the automobile, said device including abutment means interengagable with a moveable detent member adapted to be mounted adjacent said abutment means, said detent being moveable between an engaging and disengaging position

.,» wherein the detent member in said engaging position prevents rotation of said wheel and said shaft, the forces applied to said detent member through rotation of said shaft being applied directly to said housing by force transfer means.

Conveniently, said abutment means comprises a ό _,b. slidable member mounted between said shaft and a bed of preferably resilient material, such as hard rubber or plastic such that in use a squeezing force is applied between the steering shaft and the abutment means in the locking position such that the shaft can be turned only with great difficulty.

In a more specific form of the invention, the force transfer means is an apertured plate fixed internally to said housing, said detent member being slidably held within said apertured plate so that any applied force by said abutment means has a shear effect on said detent means and the applied force is transferred directly to the housing.

Thus, there is provided a device rendering the steering mechanism inoperative by locking, which is difficult to tamper with in an unauthorised manner and is stronger and more effective than a conventional steering column locking system.

There is also provided, according to the present invention, an anti-theft locking device for an automobile comprising a steering shaft with a ratchet member thereon rotatable with said shaft, a pawl device engagable with the teeth of said ratchet, said pawl being pivotally connected to the steering shaft housing, actuating means under the control of a steering lock/ignition lock mechanism for moving said pawl about said pivot into and out of engagement with said teeth such that rotation of the steering shaft in one direction only is possible when engaged.

There is also provided in a further aspect of the present invention, a locking device for an automobile ignition/steering lock system comprising, a two-part rotatable locking barrel mounted in a lock housing substantially in axial alignment, both barrels including locking tumblers actuatable by a key or like device and adapted to operate an ignition switch and a steering lock mechanism upon rotation of said barrels, the arrangement being such that unauthorised rotation of one barrel part only is ineffective in operating said switch and lock mechanism.

Whilst it is desirable that both barrels include locking tumblers, in practice, it is merely required that the barrels be maintainable in alignment to allow easy access of a valid key. Accordingly, it is desirable that both barrels include locking tumblers to provide a maximum number of key combinations.

The present invention involving the provision of a ,_ two-part rotatable locking barrel may be utilised with an electromagnetic actuating mechanism for the steering lock as will be described in more detail later.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in greater detail having reference to the accompanying drawings in which :

Figure 1 is a sectional view of an embodiment of a tamper proof lock according to the present invention.

Figure la is a partial sectional view of a modified l _.b._ form of lock,

Figure 2 is a sectional view of an embodiment of a steering shaft lock mechanism.

Figure 2a is a perspective view of a hinged detent member.

Figure 2b is a detailed view of a connection member for the detent member.

Figure 3 is an end view of a further embodiment of an a steering lock mechanism.

Figure 4 is an end view of a further embodiment of a steering lock device.

___> 3

Figure 4a is an end view of a further embodiment of a steering lock device.

Figure 5 is a sectional view of a further embodiment of electromagnetic actuation coupled with the ignition lock system.

Figure 6 is a side view of part of a modified steering column mechanism as known on some General Motors vehicles.

Figure 7 is a partial end view of the modified assembly of Figure 1.

Figure 8 is a perspective view of a clutch collar for use in the assembly of Figures 1 and 2.

Figure 9 is a partial sectional view of a cluth device. Figure 10 is an elevational view of a conventional steering shaft lock modified according to the invention with the provision of a clutch device of Figure 4 in disassembled form. 5 Figure 11 is an elevational partial view of a modified key locking mechanism.

Figure 12 is a cross-sectional view of Figure 4. DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to Figure 1, this Figure refers to *1_0 an ignition key lock device 19 comprising a cylinder 10 housing a pair of aligned barrels 11,12 which are interconnected by lug 13 preventing separation but allowing relative rotation of said barrels. Both barrels 11,12 include conventional lock tumblers which are key actuable in *5 conventional manner. The collar of the second barrel 12 is linked to a connecting member 14 rendering it rotatable with said second barrel which is arranged to turn the spigot 15 by engagement with extension piece 15a. The connecting member 14 is adapted to drive the linkage 16 connected to o the steering lock mechanism (Figure 4) which may be of conventional form such as, for example, shown in Figures 2, 2a, 2b and 3 of this specification.

The spigot 15 is adapted to actuate the ignition switch in known manner. The connection between the linkage 5 16 and the connecting member 14 is sufficiently strong to actuate the steering lock mechanism under normal circumstances but will be disabled if the barrels 11,12 are extracted illegally. The spigot 15 is free to turn independently of the connecting member 14. 0 Considering a situation where illegal actuation of the barrels 11,12 is attempted, for example with a screwdriver, it is possible for a screwdriver blade to be forced part way into the key aperture of barrel 11 and it may be also possible to forcibly turn barrel 11. However, the connecting lug 13 between the two barrels allows rotation of barrel 11 relative to barrel 12 so that turning of the barrel 11 will be ineffective in actuating the ignition lock and the steering mechanism. The key slot may be configured so that a strong broad bladed implement, such as a screwdriver, cannot penetrate to the second barrel 12. This is done by making the slot of irregular cross-section so that only a c relatively weak pointed instrument can be inserted to penetrate through, but which is of insufficient strength and imparts insufficient leverage, to forcibly turn the second barrel 12.

Extraction of the barrel housing 10 can be made

-i_Q extremely difficult, if not impossible, by providing a pin 17 connecting the barrel housing 10 with the cylinder housing 19.

It may be possible to remove the barrels in the embodiment shown in Figure 1, however, the connection ιc between linkage 16 and connecting member 14 is relatively weak so that forced removal of the barrels 11,12 if achieved, will only serve to break the connection to linkage 16 and render it inoperable and still inaccessible. The connecting member 14 would be free to turn without effect.

2o Additionally, a strong blocking member 18 may be positioned in the bottom of the cylinder 19 to secure against access from the bottom of the cylinder.

With reference to Figure la, the first locking barrel 11 may be retained by a modified pin 17a extending

_2ς through the outer housing 19 and inner cylinder 10 to render removal of the barrel 11 virtually impossible. This construction lends itself to use of the split barrel idea in a conventional outer lock casing such that conversion of an existing ignition lock system can be simply carried out in

3_Q accordance with this invention whereby a conventional single locking barrel can be replaced by the dual locking barrel of the present invention made up of barrels 11 and 12.

With reference to Figure 2, this shows a cross sectional view of the housing and steering shaft showing a

T_C ratchet like member 30 secured on the shaft 21.

A detent member 31 is pivotally secured to the housing 24 by a hinge member 32. The detent member 31 is moveable under the influence of actuation member 33 operatively connected to a conventional ignition key lock (not shown) .

The ratchet like member 30 includes abutment surfaces 30a and ramp surfaces 30b against which the detent member 31 is adapted to engage when moved into position by actuation member 33.

Thus the steering shaft may move in a clockwise direction but is prevented from moving in an anti-clockwise direction by abutment of the detent member 31 against any of

, _Λ the abutment surfaces 30a. 10

If the wheel is turned in a clockwise direction eventually the steering box moves to the limit of its steering lock, but cannot be reversed whilst the detent member is in position as shown, thus making the vehicle

, _ undriveable . 15

The detent member 31 is connected to the actuating member 33 by spring clip 34 attaching to ball 35.

The actuating member 33 is reciprocal by actuation of a conventional steering wheel lock upon turning of a key barrel . 20

The detent member 31 may be spring biased on its pivot point so that accidental movement into engagement with the abutment surfaces is avoided when in use.

With reference to Figures 2a and 2b, these are views showing detail of the detent member 31 and hinge member 32 and the juxtaposition of the retaining spring clip 34 for connecting the detent member to the actuating member 33.

With reference to Figure 3 of the drawings, this depicts a conventional steering shaft and housing within 30 which a conventional locking rod 40 is mounted for reciprocating movement in response to turning of an ignition lock key.

Referring to Figure 2b, spring component 34 is releasably attached to link 35 so that upon illegal removal of the ignition locking mechanism (if possible), the spring component is separated from the link 35 and the steering lock mechanism is rendered inoperative and inaccessible. According to the invention, a plate 41 (Figure 3) is fixedly secured to the housing wall 24 and apertured to hold the locking rod 40 in slideable relation therewith and allows movement of the rod into engagement with the steering shaft 21.

The plate 41 is closely adjacent to the steering shaft 21 so that any forced movement of the steering shaft acts as a shear force on the locking rod 41 and does not transfer any significant force to the ignition locking mechanism nor the linkage attaching the locking rod to the ignition lock.

The force is transmitted to the plate which in turn is transmitted to the strong housing chamber and renders the steering lock virtually unbreakable with applications of excessive force.

Referring to Figure 4, a steering shaft 40 is provided with a flat key surface 41 engageable with a slidable member 42 reciprocable in the direction of arrow A under the influence of a steering lock linkage (not shown, but which may correspond to the linkage 16 of Figure 1, or 33 of Figure 2). The shaft housing 43 has fitted therein a block member 44 which is preferably of hard rubber or plastic material which is compressible to a certain extent under considerable load.

In operation with the slidable member 42 in position as shown, the flat surface 41 of the steering shaft engages the slidable member thereby preventing turning of the shaft under normal conditions. However, if considerable force is applied to the shaft the rubber or plastic member 44 may resile sufficiently if the pressure is great enough to allow the shaft to turn but only with difficulty.

Thus, whilst normal operation of the steering would not be possible with this arrangement, nevertheless, turning of the shaft will occur before there is any chance of mechanical or structural damage being caused to the componentry. Figure 4a shows a further modification wherein a collar member 45 is fitted to the shaft 40 as by welding, thus the shaft 40 retains its full cross-section and resultant strength. _j. The operation of the mechanism is otherwise similar to that described for Figure 4.

With reference to Figure 5, this refers to a lock-up anti-theft device for a steering shaft actuated by electromagnetic means which can be coupled to a locking

₁ _ barrel having a similar principle of operation to that previously described wherein twin rotatable barrels are provided.

The anti-theft device comprises a steering wheel 20 fixedly attached to a steering shaft 21 which in turn, has a

_. _ locking disc sheer member 22 fixedly secured thereto by member 23. The disc member 22 is adapted to be locked to the steering coloum housing 24 by a locking rod 25 which is reciprocal, under the influence of a push/pull solenoids

26,26a in a fixed collar member 28. In the position shown, the locking rod effectively locks the disc 22 to the housing member 24 through collar member 28 and prevents any movement of the steering wheel and the steering mechanism at the end of the shaft. The reciprocal rod 25 is maintained in a stable relationship in the position shown by a bistable _ς spring 27 which biases the locking rod into position.

Upon switching of the current flow through leads

29,30 to the solenoids 26,26a the locking rod is moved to the right of the drawing into its other stable position (not shown), to withdraw the rod 25 so that effectively the rod unlocks itself from the locking disc 22 whereby the steering mechanism can be operated in the normal manner by the steering wheel 20.

To ensure easy locking of the steering wheel in any particular attitude, a number of apertures 22a are provided

__ in the locking disc. __> b

The collar 28 is located closely adjacent to the disc member 22 thus ensuring that any transverse force on the rod 25 caused by forcing the locked steering shaft, for example, will be applied to the rod substantially in sheer, and furthermore, all forces transmitted directly to the relatively strong housing 24.

The wiring 29 and 30 is connected to a modified form of the ignition locking tumbler switch as will be now described.

The twin locking barrels 12 and 13 are mounted in the housing 10 and 19 as previously -described and further description of this aspect is deemed not necessary.

Connecting member 65 is adapted to be turned by the locking barrels 12 and 13 when a legitimate key is inserted therein.

The connecting member 65 is connected to a disc member 66 which is adapted to make electrical connections to the circuit board 67.

Thus, in authorised operation of the locking barrels, the disc member 66 is adapted to make electrical connections to the wiring of the electromagnets 26 to actuate the steering locking mechanism.

To prevent easy access to the wiring 30 leading from the switch to the steering column, armouring 69 is provided for the lead to the actuating magnet 26 which is actually effective in the disconnection of the steering lock mechanism.

If the armouring 69 is removed the lead 30 is adapted to be removed and disconnected from the connection to the solenoid 26 thereby rendering the mechanism inoperative.

The disc member 66 is divided into two parts so that if the locking barrels 12,13 are removed from the cylinder illegally the connecting member 65 is drawn up into the skirt member 68 which effectively removes the disc member 66 from the end of the connecting member 65 rendering it useless to make electrical contact to the circuit board

67.

It will be appreciated that a simple electro¬ magnetic actuation mechanism coupled with the tamper proof ignition locking system is effectively provided by this embodiment. With reference to Figures 6, 7 and 8, the shaft locking mechanism shown is modified to provide a slipping feature. The advantages of a slipping clutch on a steering lock are documented but mainly relate to providing "give" in c the lock so that in the event of attempted unauthorised forcing of the mechanism, the parts can move relatively before breakage can occur, but yet the mechanism is so stiff as to be inoperable for practical purposes. As mentioned previously, such a result is disclosed in U.S. Patent No. ι π 3,566,633.

The mechanism shown in Figure 6 is a modified version of a lock used on some General Motors vehicles in which a tooth gear (-110) is engagable by an axially movable pawl (111) slidably mounted on a non-rotatable sleeve (112) ■_jc so that when the pawl engages the gear (110) the steering wheel and attached shaft cannot rotate.

The modification according to the invention is as follows :

The pawl (111) is reduced in depth (see Figure 7) 2o so that it is adapted to frictionally engage a sleeve member (113) (Figure 8) which has been mounted on the toothed gear (110) as shown best in Figure 7. The members (113a) are preferably of resilient material such as spring steel. The dimension of the pawl (111), tooth gear (110) and sleeve 5 member (113) is such that the components have the ability to allow restricted or braked relative movement, but only where a relatively strong force is applied to the steering wheel of the steering mechanism.

In this way the parts are relatively movable under stress but not operable for practical purposes. That is, in the normal steering operation of a moving motor vehicle. Thus it will be appreciated that the conventional steering lock illustrated can be modified in a relatively simple manner such that actual breakage of the steering shaft lock r is very difficult to achieve. The remaining area of apparent weakness, namely the key locking mechanism can embody the twin barrel device disclosed in my earlier patent application referred to previously in replacement for the conventional ignition key 5 locking device.

With reference to Figures 10 and 11, Figure 10 shows a sleeve member (120) slidably mounted over a conventional locking plate (121) secured to a steering shaft (122). The sleeve and plate are both slotted at (120a) and -_j_0 121a), which slot is adapted to house a locking key member (123) therein best shown in Figure 4 which shows the sleeve (120) in assembled position. The locking key member may be of half round tube (123a), that is tube cut longitudinally (as shown in Figure 12) to rest in the slotted portion -_j_5 (120a) and adapted to engage the edges of the slot (120a) of the sleeve.

The locking key member should be of compressible or resilient material, so that in use the member may be deformed to allow relative movement of the sleeve member o (120) and the locking plate (121).

The slot (120a) is adapted to receive a locking pawl of a conventional steering lock mechanism such as for example shown in Figure 8 of my earlier referenced specification. 5 When the locking pawl is engaged the sleeve (120) is from turning by engaging with the locking key member (123). This arrangement is such that the relative movement between the sleeve and the locking plate or shaft is possible if sufficient turning force is applied to the 0 steering shaft. However, the frictional force between the components is too great to allow normal operation of the steering mechanism during normal use of the motor vehicle.

The conventional shaft lock shown is of the type utilised by the Ford Motor Company and most other manufacturers of vehicles, and it will be appreciated that simple modification will allow for the provision of a slipping clutch feature to avoid or minimise damage to the existing components used in the conventional steering lock mechanism. That is the force to cause deformation of the locking key is balanced between the need to create sufficient resistance and yet to avoid component damage in the steering lock mechanism. 5 Finally, with reference to Figure 11, there is shown a part of a pawl actuating mechanism suitable for fitment to the ignition locking system of Ford Motor vehicles in particular. In a conventional lock the members (130) and (131) are an integral piece rotatable by the key o operated locking barrel (not shown) to reciprocate the locking pawl (not shown) for engagement in the locking slot of a steering shaft, for example as shown in Figures 9 and 10.

One of the problems encountered is the relatively *l_5 easy manner of removing the locking barrel from the ignition lock in conventional lock systems which leaves the member (130), (131) open to easy access and turning to unlock the shaft locking mechanism.

Part of this problem is overcome as disclosed in my 0 earlier patent application by rendering it difficult to break the barrel and/or remove the barrel from its housing (136).

The arrangement shown in Figure 11 prevents easy access to the pawl actuating mechanism by dividing the pawl 5 actuating mechanism into two parts as shown such that they are still rotatable with one another and retained in engagement with one another as shown. This retention is for example by spring means (132) whilst part (130) is fitted with a key aperture (133) entering engagable with a head 0 (134) of part (131) .

The head (134) and aperture (133) are separable upon application of axial force to part (130) such as by an attempt to remove the locking barrels, (not shown) connected to the part (130) . If this happens the parts will separate because axial movement of part (131) can be restricted by pin (135). If the separation does occur, reconnection of the two parts is impossible because part (131) is allowed to fall out of contact with part (130). It is important that part (130) cannot be completely removed from the housing (136). For this purpose pin (137) is fixed in housing (136) and is engagable with flange (138) and part (130). The distance of travel of part (130) is sufficient to ensure the disengagement of the two parts (130), (131) occurs when an attempt is made to illegally remove part (130) from the housing (136).

Accordingly, a very simple means of modification to existing ignition locks/steering locks is achievable as fitted to existing vehicles and can render the existing steering lock mechanisms virtually tamper proof either as replacement parts or in the case of original factory built equipment.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS;

1. An anti-theft locking device for an automobile including a steering shaft encased in a housing, said shaft connecting a steering wheel to the steering mechanism of the automobile, said device including abutment means interengageable with a moveable detent member adapted to be mounted adjacent said abutment means, said detent being moveable between an engaging and disengaging position wherein the detent member in said engaging position prevents rotation of said wheel and said shaft, the forces applied to said detent member through rotation of said shaft being applied directly to said housing by force transfer means.

2. An anti-theft locking device wherein said abutment means comprises a slidable member mounted between said shaft and a bed of resilient material, such that in use, a squeezing force is applied between the steering shaft and the abutment means such that the shaft can be turned with difficulty.

3. An anti-theft locking device comprising a two-part rotatable locking barrel mounted in a lock housing substantially in axial alignment, both barrels including locking tumblers actuatable by a key or like device and adapted to operate a switch and/or lock mechanism upon rotation of said barrels, the arrangement being such that unauthorised rotation of one barrel part is ineffective in operating said switch and/or lock mechanism.

4. An anti-theft locking device for an automobile including a steering shaft enclosed in a housing, said shaft connecting a steering wheel to a steering mechanism of the automobile, said device including electromagnetic locking and unlocking means for rendering the mechanism useable and not useable, electrical connection to said electromagnetic means being controlled by a locking device as claimed in Claim 3 wherein said switch controls flow of current to said electromagnetic means from a remote location.

5. A vehicle anti-theft steering lock device for fitment to a steering shaft, the device having a locking pawl selectively operative with the shaft to prevent rotation of the shaft, including clutch means adapted to be mounted between said steering shaft and said locking pawl and selectively engagable with said locking pawl, said clutch means including resilient spring means for creating a torque against relative movement of the shaft and the clutch means but which allows relative movement upon application of predetermined turning force, said force being sufficient to prevent normal operation of the steering shaft.

6. In a vehicle key ignition lock for operating a pawl on a steering lock mechanism comprising actuating means operably engagable with said pawl to operate said steering lock mechanism upon operation of said key ignition lock, wherein said actuating means is so mounted relative to said ignition lock that unauthorised tampering with said lock renders actuating means inoperable and inaccessible.

7. In a key actuated lock there is provided an actuating means operably engagable with a mechanism wherein said actuating means is so mounted relative to said key actuated lock that unauthorised tampering with said lock renders said actuating means inoperable and inaccessible.