GB2257676A

GB2257676A - Vehicle steering lock

Info

Publication number: GB2257676A
Application number: GB9213582A
Authority: GB
Inventors: Clauido Fissolo
Original assignee: TRW Sipea SpA
Current assignee: TRW Sipea SpA
Priority date: 1991-07-09
Filing date: 1992-06-26
Publication date: 1993-01-20
Anticipated expiration: 2012-06-26
Also published as: ITTO910163U1; ES1022686U; FR2679504B1; IT223027Z2; GB2257676B; JPH0732973A; YU67892A; GB9213582D0; DE9208698U1; FR2679504A1; ITTO910163V0; ES1022686Y

Abstract

A vehicle steering lock wherein the steering shaft (13) is locked by a bolt (53) moving inside a seat (15) on a metal block (11). The bolt (53) is sprung inside a seat (16) on the shaft (13) and reloaded each time by a cam (33) operated by a key via a lock (21). In the event of the hollow body (8) of the lock (21) being forced, the bolt (53) is locked by a spring element (56), which is normally maintained locked by a profile of the cam (33), via a pin (63), even when the key (26) is withdrawn. <IMAGE>

Description

VEHICLE STEERING LOCK The present invention relates to a vehicle steering lock comprising a body housing a control-key-actuated lock.

With the increase in road vehicle traffic, vehicle theft has now become a major source of concern. On modern vehicles, therefore, the key controlling the electric system and startup of the engine normally also provides for locking the steering shaft when the key is withdrawn. Such devices, however, may be de-activated in various ways, e.g. by forcing the lock, in which case, nothing is to be gained by providing for a stronger lock design.

On one known steering lock device, the lock member is controlled by a key-actuated shaft, and is engaged in the steering shaft release position by a safety element moving parallel to the shaft. The lock member is also provided with a retaining element, for maintaining it in the lock position, and which is loaded each time by a spring acting on the safety element. This type of device, however, is of complex design, and not very reliable in the event of it being forced.

It is an object of the present invention to provide a straightforward, reliable steering lock, designed to prevent release of the steering mechanism even in the event of the lock being forced.

According to the present invention, there is provided a vehicle steering lock comprising a body housing a lock operated by a control key; said lock controlling a member for locking the steering shaft when said key is withdrawn; and said member moving on a portion of said body adjacent to said shaft; characterized by the fact that said portion houses a safety device for automatically locking said member in the steering shaft lock position in the event of distortion or breakage of said body, or removal of said lock.

A preferred non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which: Fig.l shows a cross section of a steering lock in accordance with the present invention, in the locked position; Fig.2 shows a partial section along line II-II in Fig.l; Fig.3 shows the same section as in Fig.l, in a different operating position; Fig.4 shows a partial section along line IV-IV in Fig.3; Fig.5 shows an enlarged detail in Fig.3 in the operating position; Fig.6 shows the same section as in Fig.l subsequent to forcing; Fig.7 shows an enlarged detail in Fig.6.

Number 5 in Fig.l indicates a vehicle steering lock comprising a known electric system switch block 6.

Block 6 is housed in a first compartment 7 of a body 8-11 having a hollow portion or body 8 made of plastic material and comprising two flanges 9 fitted with a rigid portion consisting of a block 11. Block 11 is made of metal, preferably a tough light metal alloy, such as that known commercially as "Zama", designed to withstand distortion or breakage.

Block 11 presents a cylindrical seat 12, and is fitted to the vehicle with seat 12 adjacent to the steering shaft or column 13, which rotates inside a sleeve 10 fitted to a bracket 14 having two flanges 20 fitted to both flanges 9 and block 11. Block 11 presents a prismatic guide 15 aligned with an opening 25 in sleeve 10 and preferably radial in relation to column 13, which presents at least one radial recess 16 of the same width as guide 15, and which is aligned with opening 25 and guide 15 in a predetermined angular position of column 13.

Body 8 also comprises a second substantially cylindrical compartment 17 separated from compartment 7 by an inner flange 18 with a center hole 19, and housing a lock 21 comprising a combination cylinder 22 fitted angularly and axially inside compartment 17. Lock 21 also comprises a shaped flange 23 housed inside a seat 24 and having a keyway for the insertion of an operating key 26 (Fig.3).

Lock 21 comprises a shaft 27 rotating and moving axially in relation to cylinder 22, and connected by a joint 28 to a shaft 29 fitted in one piece with a disk 31 axially comprising a cylindrical portion 32 and a cam portion 33. An angular portion of cam portion 33 presents a profile in the form of a cylindrical surface 34 of the same diameter as portion 32, and the function of which will be described in detail later on.

The remainder of cam portion 33 comprises an upward profile 36 (Fig.4), and a cylindrical profile 37 of a smaller diameter than surface 34. Profiles 36 and 37 provide for activating a substantially prismatic, trapezoidal-section appendix 38 on a slide 39 sliding inside a prismatic radial opening 40 in body 8 and inside a corresponding opening 41 formed in rigid block 11 and aligned with opening 40.

Slide 39 presents an opening 42 for the passage of an extension 43 of shaft 29 (Fig.1) engaged inside hole 19 and terminating in a prismatic end portion 44 for activating switch 6. A compression spring 45 acting on portion 44 normally maintains extension 43 and shaft 29, together with disk 31 and joint 28, in the right-hand side position shown in Fig.1.

Slide 39 presents two lateral appendixes 46 (Fig.2) housed inside respective seats 47 located on either side of opening 40 in body 8 and also housing respective compression springs 48 for normally maintaining slide 39 against shoulder 49 of block 11, as shown in Fig.2. Slide 39 also presents an appendix 51 engaged inside a recess 52 in a lock member consisting of a prismatic-section bolt 53 designed to engage guide 15 of block 11 and recess 16 of column 13.

Lock 21 presents a safety device 54-64. More specifically, bolt 53 presents a recess 54, which, when bolt 53 is engaged inside recess 16 as shown in Fig.l, corresponds with a cylindrical hole 55 in block 11. Hole 55 houses a sliding spring element 56 comprising a piston 57 (Fig.5) sliding inside a cylindrical seat 58; and a head 59 on which acts a compression spring 60 located between the flat surface of head 59 and a washer 61. Head 59 also presents a conical surface 62 with which cooperates a lock element consisting of a pin 63 sliding inside a hole 64 perpendicular to hole 55 and thus radial in relation to disk 31. As shown clearly in Fig.l, one of flanges 20 of bracket 14 covers and so prevents safety device 54-64 from being tampered with externally.

The above steering lock operates as follows.

When key 26 is inserted inside lock 21 in the drive position, as shown in Fig.3, slide 39 is maintained in the Fig.3-4 position by profile 37 of cam portion 33 of disk 31; bolt 53 is released from recess 16 by slide 39, thus enabling steering- column 13 to rotate freely; and cylindrical surface 34 of cam portion 33 engages pin 63 and conical surface 62 of head 59 (Fig.5), so that spring 60 in ineffective.

When key 26 is turned to the stop position (Fig.3), shaft 27 of lock 21 is rotated, together with shaft 29 and disk 31, anticlockwise in relation to the Fig.4 position; profile 36 of cam portion 33 of disk 31 releases appendix 38, so as to raise slide 39, together with bolt 53, by means of springs 48; and bolt 53 engages recess 16, thus locking steering column 13 and bringing recess 54 into line with piston 57 as shown in Fig.l.

When key 26 is withdrawn, spring 45 moves extension 43, together with shaft 29 and disk 31, rightwards; and profiles 36, 37 release appendix 38, while surface 34 of portion 33 remains engaged with pin 63, as shown in Fig.l. To release column 13 and bolt 53, key 26 must be re-inserted inside lock 21, so as to move disk 31 leftwards and compress spring 45.

When key 26 is turned clockwise, profile 36 of cam portion 33 engages appendix 38 so as to reload slide 39; slide 39 moves back down together with bolt 53, so as to release column 13; and end portion 44 of extension 43 activates switch 6 for turning on the instrument panel.

As of this position, key 26 may be turned further for starting the engine, after which, it returns to the drive position shown in Fig.s 1 and 2.

In the event of body 8 being forced or broken as shown in Fig.6, subsequent to withdrawing key 26 from lock 21 as shown in Fig.1, the entire lock assembly 21, together with shafts 27 and 29, extension 43 and disk 31, moves rightwards, so that surface 34 of cam portion 33 releases pin 63 (Fig.s 6 and 7).

As a result, conical surface 62 of head 59, via spring 60, moves pin 63 towards the axis of disk 31; and piston 57 engages recess 54, thus preventing slide 39 from being reloaded and steering column 13 from being released. Even in the event of lock 21 being removed together with disk 31, and pin 63 being extracted from hole 64, bolt 53 could not be released from piston 57 short of dismantling the entire steering lock.

The advantages of the steering lock according to the present invention will be clear from the foregoing description. In particular, it provides, using extremely straightforward, effective means, for preventing release of the steering column by in any way forcing or tampering with the lock.

To those skilled in the art it will be clear that changes may be made to the steering lock as described and illustrated herein without, however, departing from the scope of the present invention. For example, guide 15 may be inclined, as opposed to radial, in relation to column 13; bolt 53 may be rotated about the axis of slide 39, for more effectively locking column 13; and disk 31 may be so sized or altered as to also release pin 63 in the event of lock 21 being forced or extracted leftwards, without damaging body 8.

Claims

1) A vehicle steering lock comprising a body (8-11) housing a lock (21) operated by a control key (26); said lock (21) controlling a member (53) for locking the steering shaft (13) when said key (26) is withdrawn; and said member (53) moving on a portion (11) of said body (8-11) adjacent to said shaft (13); characterized by the fact that said portion (11) houses a safety device (54-64) for automatically locking said member (53) in the steering shaft lock position in the event of distortion or breakage of said body (8-11), or removal of said lock (21).

2) A steering lock as claimed in Claim 1, wherein said member (53) moves in relation to said shaft (13) for engaging a recess (16) on the same; characterized by the fact that said safety device (54-64) comprises a spring element (56) pushed by a spring (60) into a seat (54) on said member (53) when engaged inside said recess (16).

3) A steering lock as claimed in Claim 2, characterized by the fact that said spring element (56) is normally locked, against the action of said spring (60), by a lock element (63) controlled by said lock (21).

4) A steering lock as claimed in Claim 3, characterized by the fact that said portion (11) is rigid and designed to withstand attempted distortion or breakage; said lock element consisting of a pin (63) sliding in a seat (64) on said rigid portion (11); and said lock (21) being housed in a hollow portion (8) of said body (8-11).

5) A steering lock as claimed in Claim 4, characterized by the fact that said rigid portion consists of a metal or metal alloy block (11); said hollow portion (8) being made of plastic material.

6) A steering lock as claimed in Claim 4 or 5, characterized by the fact that said spring element (56) comprises a piston (57) sliding in a guide (58) on said rigid portion (11) perpendicular to said pin (63); said spring element (56) presenting a cam surface (62) acting on said pin (63).

7) A steering lock as claimed in Claim 6, characterized by the fact that said cam surface consists of the conical surface (62) of the head (59) of said spring element (56); said head (59) also having a flat surface acted on by said spring (60).

8) A steering lock as claimed in one of the foregoing Claims from 3 to 7, wherein said member (53) is integral with a slide (39) moved elastically for engaging said member (53) in said recess (16), and reloaded by a cam (33) rotated by said key (26); characterized by the fact that said lock element (63) is normally locked by a surface (34) of said cam (33).

9) A steering lock as claimed in Claim 8, characterized by the fact that said member (53) and said slide (39) move substantially perpendicular to the axis of said lock (21); said surface (34) being cylindrical, and extending over a predetermined angular portion of said cam (33).

10) A steering lock as claimed in Claim 9, wherein said cam (33) is moved axially into a first position upon withdrawal of said key (26); characterized by the fact that the axial dimension of said cam (33) is such that it remains engaged with said pin (63) in said first position, and releases said pin (63) when forced into a second position.

11) A steering lock as claimed in one of the foregoing Claims, characterized by the fact that said shaft (13) rotates in a sleeve (10) connected to said body (8, 11) by a bracket (14) having a portion (20) for protecting said device (54-64).

12) A vehicle steering lock having a locking member movable between a lock position and an unlock position under the control of a key mechanism, the lock comprising safety means which tends to retain the locking member in the lock position if the key mechanism is removed.

13) A vehicle steering lock substantially as described with reference to the accompanying drawings.