AU642452B2

AU642452B2 - Improvements in steering locks

Info

Publication number: AU642452B2
Application number: AU68203/90A
Authority: AU
Inventors: Manfred Linke; Yoram Shevach
Original assignee: Robert Bosch Australia Pty Ltd
Current assignee: Robert Bosch Australia Pty Ltd
Priority date: 1989-12-19
Filing date: 1990-12-19
Publication date: 1993-10-21
Anticipated expiration: 2010-12-19
Also published as: AU6820390A

Description

AUSTRALIA

PATENTS ACT' 1952Fom1 COMPLETE SPECIFICATION

(ORIGINAL)

FOR OFFCE USE 64

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Short Title:5

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Int. Cl: Application Number: Lodged: "(evaplete Specification -Lodged: 6400 Accepted: :Lapsed: Published: liorty: Related Art: 0 TO BE COMPLETED BY APPLICANT *Nalne of Applicant ROBERT BOSCH (AUSTRALIA) PTY. LTD.

00 Address of Applicant Cnr. Centre McNaughton Roads, Clayton, 3168, Victoria, Australia.

Actual Inventors-, Yoram Shevach and Manfred Linke Address for Service, CALLINAN LAWRIE, 278 High Street, Kew, 3101, Victoria, Australia Complete Specification for the invention entitled: "IMPROVEMENTS IN STEERING LOCKS" The following statement is a full description of this invention, Vi.cluding the best method of performing it known to me:l The present invention relates to improvements in steering locks used in motor vehicles.

Steering locks have been incorporated in motor vehicles for many years.

They consist of a housing which is clampingly engaged to the steering column.

The steering shaft usually includes a recess which co-operates with a lock bolt in an interfering manner. The lock bolt is usually moved in a reciprocal manner by an eccentrically driven shaft passing through it. The shaft is spring loaded and is moved by being coupled to a lock barrel fitted into the housing. The shaft has a flange, intermediate its length, on which normally rides a spring loaded safety ,1i 1 m, pin which holds the lock bolt from engaging the recess in the steering column.

When the shaft is turned to the lock position the shaft is pushed rearwardly causing the spring loaded safety pin to fall off the flange. With the safety pin

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released the lock bolt is pushed home into the recess of the steering column.

Without the key to the lock barrel it should not be possible to extract the lock bolt i5s.. from the recess.

a Unfortunately such steering locks are still not secure. The lock barrel is usually located in a cylindrical extension of the housing. By slipping a tubular sleeve over this cylindrical extension, and applying leverage to the sleeve, it is possible to snap off the extension. Once broken, a thief has access to the shaft which can then be turned to retract the lock bolt and operate the ignition switch.

Similarly, if the thief can prise out the lock barrel the shaft will again be exposed.

With these problems in view the invention, in its various forms, proposes to make it more difficult to tamper with a steering lock.

In one form the present invention provides a steering lock with a housing shape which prevents use of a sleeve to break part of the housing containing the -2lock barrel.

In another form of the invention an object of the invention is to prevent rotation and/or axial movement of the shaft from an unauthorized tampering of the lock barrel.

In yet another form of the invention disabling of the ignition system is provided when tampering of the steering lock occurs.

With the above objects in view the present invention provides a steering wheel lock including a housing, a mechanism for moving a lock bolt and a lock barrel, said mechanism including a rotatable shaft coupled to said lock barrel for rotating said shaft from its locked to unlocked positions, said mechanism including a device which prevents rotation of said shaft in one or more directions if said lock barrel is removed from said housing.

Preferably said housing in the proximity of said lock barrel is spherical or bullet nose shaped.

1: Preferably said device includes a biased latch which co-operates with a cam o on said shaft when said lock barrel is removed.

o° b *o o* C~~S-3- In order that the invention may be dearly understood and readily put into practical effect, preferred non-limitative embodiments of a steering lock made in accordance with the invention will now be described with reference to the accompanying drawings. In the drawings:- Fig. 1 is a longitudinal cross-sectional view of a steering lock, without the security lock device fitted, made in accordance with the present invention and having the lock barrel and ignition switch installed; Fig. 2 is a front view of the steering lock shown in Fig. 1 showing the lock barrel removed; Fig. 3 is a rear view of the steering lock of Fig. 1 but in the off position; Fig. 4 is a cross-sectional view along and in the direction of arrows 4-4 shown in Fig. 1; Fig. 5 is a similar view to that of Fig. 1 showing the unlocked position of the steering lock; Fig. 6 is a cross-sectional view along and in the direction of arrows 6-6 shown in Fig. Fig. 7 is a similar view to that of Fig. 1 showing the security lock device fitted; Fig. 8 is a cross-sectional view along and in the direction of arrows 8-8 shown in Fig. 7; Fig. 9 is a perspective view of the security lock device shown in Fig. 7; Fig. 10 is a perspective view of a part of the shaft of the steering lock shown in Fig. 1; and Fig. 11 is a cross-sectional view of a modified end part of an ignition switch mechanism showing additional circuitry which may be used with the steering -4lock.

Turning to the drawings there is shown a steering lock 20 having a housing 1 formed by casting. Housing 1 includes a first bore 22 for reception of a lock barrel 6, a second interconnected bore 24 through which passes shaft 5 and a stepped bore 26 for reception of an ignition switch 28. A chamber 30 is provided for holding the working mechanism of the steering lock. The housing 1 has a stubby spherical or bullet nose shaped front end 32 which provides insufficient length or shape for slipping a sleeve thereover for breaking the housing. Annular ribs 34, bridged by radial ribs 36, make it difficult to utilize a slip-on tool to break the housing.

Shaft 5 includes a coupling element 38 which co-operates with lock barrel 6 to allow shaft 5 to be rotated in synchronism with a key (not shown) inserted into the lock barrel. Shaft 5 is biased by spring 7 in the right hand direction as shown in Fig. 1. Longitudinal movement of shaft 5 is allowed and is controlled by an axially movable component (not shown) from within lock barrel 6. Shaft 5 includes an annular flange 5.1 and a cam 5.3. Shaft 5 has a 3tem 40 which is 6 basically semi-circular in cross-secton as shown in Figs. 4 and 10. Stem extends through chamber 30 and has a protruding radial tab 14. A stub axle 42 completes shaft 5 and is coupled to ignition switch 28 by being keyed on switch rotor 29 which acts as an end bearing.

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Located in chamber 30 is a lock bolt guide 2 with a reciprocally movable lock bolt 3 which co-operates with a recess (not shown) of a steering column.

Chamber 30 is larger than bore 24 which prevents lock bolt guide and lock bolt 2 from being withdrawn through bore 24. Lock bolt 3 is coupled to a cam 9 which is biased by spring 8 into the locked position (Fig. Cam 9 has located therein an L-shaped safety pin 4. Pin 4 is biased by spring 44. In Figs. 1 and 7, pin 4 is shown in the locked position with pin 4 abutting the face of annular flange 5.1 To unlock the steering column shaft 5 is rotated and shaft 5 is pushed inwardly. Cam 9 will move downwardly thus retracting lock bolt 3. Safety pin 4 will then be free of its abutment with flange 5.1 and will spring outwardly to be positioned on the circumferential edge of flange 5.1. Further rotation of shaft will have pin, 4 riding on flange 5.1 thus preventing lock bolt 3 from operation as shown in Fig. ,0 To prevent lock bolt 3 from being withdrawn, if lock barrel 6 is removed, an additional lock device 46 is provided. Fig. 7 shows the lock device 46 fitted, whereas it is omitted from Fig. 1. In the preferred embodiment lock device 46 comprises a latch 48 having an arcuate shape to match flange 5.1. Latch 48 is goes basically L-shaped with hinge pin 50 (Fig. Latch 48 is located in a complementary recess 52 in lock bolt guide 2. A blind bore 54 is provided for reception of a spring 56 which biases latch 48 away from recess 52. As can be seen from Fig. 7 latch 48 has a significant depth to increase its strength. It can also be seen from Fig. 7 that latch 48 is protected from removal from lock bolt o guide 2 by the inner wall of chamber Under normal operation a small part of latch 48 rides on flange 5.2. Latch 48 is only operable when lock barrel 6 is physically removed from housing 1.

When lock barrel 6 is removed shaft 5 will be biased to the right (as shown in Fig. 7) and latch 48 will fall off flange 5.1. Latch 48 will drop behind flange 5.1 (Fig. As can be seen in Fig. 8 shaft 5 cannot then be rotated. Cam 5.3 will abut the free end of latch 48 in the anti-clockwise direction whilst pin 4 will prevent clockwise rotation. Shaft 5 is constrained in the longitudinal direction by tab 14 abutting cam 9 at one end, and flange 5.1 abutting latch 48 at the other end. As a further safety measure tab 14 is located in a keyhole 31 (Figs. 3 and which also prevents rotation of shaft 5. As shaft 5 has been immobilized access to the lock bolt 3 is denied. The steering lock will have to be physically removed to enable retraction of lock bolt 3. Although a specific latch 48 has been disclosed it is clear that the shape and operation thereof can be varied.

Fig. 11 shows a variation of the shape of housing 1. In this embodiment bore 26 is extended sufficiently to allow the ignition switch 28 to be fully located therein as opposed to the traditional method of having the ignition switch S.1. extending from bore 26 and being held by grub screws 58 (Fig. The additional space can also accommodate circuit 60 as hereinafter described. By totally enclosing the ignition switch, the housing may be crimped thereto to prevent removal of the ignition switch. Circuit board 60 is fastened to housing 1 by at least one threaded fastener 62. If required an insulated spacer 61 may be placed between circuit board 60 and housing 1. The circuit board can include circuitry for interfacing security features with the engine management system. In the preferred embodiment a light source 64 and light sensor 66 are provided as a compact unit. A gap 68 therebetween allows a blade 70 to pass therethrough.

Blade 70 is snap-fitted onto ignition switch rotor 29 and rotates therewith. In the position shown the ignition switch is in the locked position. Light sensor 66 is inactive as blade 70 prevents light from light source 64 from reaching sensor 66., This inactive state is transmitted, via the circuitry, to the engine management computer system of the vehicle to disable the ignition. Unless shaft 5 is turned, via the lock barrel, blade 70 will not be rotated from its position between the light source 64 and sensor 66.

-7- In a further enhancement blade 70 may i one or more axially spaced apart slots (not shown) extending in the circumferential direction of blade The slots are located below the area sensed by sensor 66. Under normal circumstances the slots have no effect on the operation of the ignition system.

However, if ignition switch 28 is removed from housing 1 blade 70 will be withdrawn from between gap 68. Light will pass through the slots in a sequential pattern. For example, in the case of two slots, the pattern will be:- no light, light (as first slot moves past the sensor), no light (when first slot has moved out of the way, light (as second slot moves past the sensor), no light (when second slot has moved out of the way) and light as blade 70 is completely withdrawn from gap 68. This sequence of light/no light can be detected by the c circuitry and transmitted to the engine management system. The sequence is fees effectively a binary serial transmission which acts as a code. This code can be acted upon by the engine management system to ensure the ignition system and/or the petrol pump is disabled. It is clear that one or more slots may be used which will produce different codes.

It will be understood that any modifications may be made in details of *fee.: design and/or construction without departing from the ambit of the invention, the nature of which is to be ascertained from the foregoing description.

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Claims

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6. go** 0000 *0 0 0 0 0 S:060 a Si The claims defining the invention are as follows:- 1. A steering wheel lock including a housing, a mechanism for moving a lock bolt and a lock barrel, said mechanism including a rotatable shaft coupled to said lock barrel for rotating said shaft from its locked to unlocked positions, said mechanism including a device which prevents rotation of said shaft in one or more directions if said lock barrel is removed from said housing. 2. The steerng wheel lock as claimed in claim 1, wherein said device includes a biased latch which co-operates with a cam on said shaft when said lock barrel is removed. 3. The steering wheel lock as claimed in claim 2, wherein said latch when said lock barrel is fitted, rides on a flange on said shaft and said shaft is resiliently biased towards said lock barrel, whereby removal of said lock barrel causes said shaft to be axially displaced allowing said latch to fall behind said flange to engage said cam. 4. The steering wheel lock as claimed in claim 3, wherein said lock bolt is coupled to a resiliently biased further cam and rotation of said shaft causes said further cam to move said lock bolt between said locked and unlocked positions. 5. The steering wheel lock as claimed in claim 4, wherein said further cam includes a resilienty biased plunger which engages said cam to prevent rotation of said cam when said lock barrel is removed. 6. The steering wheel lock as claimed in any one of the preceding claims, wherein said shaft further includes a radial tab, whereby said tab interferes with said mechanism, when said lock barrel is removed, to prevent extraction of said shaft.
7. The steering wheel lock as claimed in any one of the preceding claims, -9- wherein said housing is shaped, in the proximity of said lock barrel, in a manner preventing hollow sleeves from being slipped thereover.
8. The steering wheel lock as claimed in claim 7, wherein said shape is spherical or bullet nose shaped.
9. The steering wheel lock as claimed in claim 8, wherein said shape is formed by annular ribs bridged by radial ribs. An anti-theft system for vehicles including a steering wheel lock as claimed in any one of the preceding claims, an ignition switch adapted to be coupled to said shaft, a switching mechanism for interfacing with an engine management system of said vehicle, said switching mechanism adapted to co-operate with said ignition switch to inform said engine management system of unauthorized tampering of said ignition switch.
11. A steering wheel lock substantially as hereinbefore described with reference to the accompanying drawings. D A T E D this 14th day of JULY, 1993. ROBERT BOSCH (AUSTRALIA) PTY. LTD. By its Patent Attorneys: CALLINAN LAWRIE oo *.oS °o0o0 o •0 10