GB2180208A - Steering lock device - Google Patents

Abstract

A steering column lock device 42 comprises a casing 22' fixedly attached to a steering column and mounting an engine-key (k) operated switch unit 26. A conventional key cylinder 24' is rotatably mounted, in a stationary holder 44, in unison with a member 46. Mounted parallel with the member 46 is a slide-like manually movable latch member 48, having a cam follower projection (52) movable in unlocking cam track 54 and locking cam track 56 of the member 46. In the locked condition of the device 42, the projection 52 is at one end of the locking cam track 56. Turning of the key (k) in cylinder 24' turns the member 46 so that the projection 52 moves along the track 56 and into the track 54 at the end of which the switch unit 26 is started.When the key (k) is turned back toward the lock position, the projection 52 runs up against stopper wall 54a. To position projection 52 once again in locking cam track 56, the latch member 48 must be pulled by the knob (50) towards the user of the device 42. <IMAGE>

Description

SPECIFICATION Steering lock device The present invention relates in general to steering lock devicesfora wheeled motorvehicle, and more particularly to the steering lock devices ofthe type having a safety mechanism by which unexpected dangerous locking ofthe steering shaft due to unwillful manipulation ofthe mechanical or engine key positioned in the key cylinder during cruising ofthe vehicle is positively prevented.

Hitherto, various kinds of steering lock devices have been proposed and put into practical use, which, for theft prevention purposes, function to lock the steering shaft to prevent manipulation ofthe same when the key in the key cylinder is turned care lessly or accidentally to the locking position (LOCK) or withdrawn from the key cylinder.

Some of the devices are equipped with a safety device in orderto prevent unwillful turning of the key toward the LOCK-position and/orthe withdrawal of the same, which may cause the dangerous locking of the steering shaftduring cruising ofthevehicle.

However, some of them are constructed to require to the operator or driver a troublesome work for handling the safety device.

It is therefore an object of the present invention to provide a steering lock device having an improved safety mechanism which can be easily handled.

Forfulfilment of the above and further objects, the steering lock device according to this invention adapted for locking the steering shaft of a wheeled motor vehicle by holding a key cylinder art a certain specifically selected angular position, called "LOCK"position, wherein the said steering shaft being unlocked by bringing said key cylinderto other positions than the said specified one and through a rotatable member in unison therewith and operatively connected with a shaft-locking bar mechanism, said device being characterized by that said rotatable member is formed at its outer peripheral surface with a reciprocatingly double-acting, elongated and substantially one way camming area extending between the LOCK-position and a remote another position, called START-position and cooperating with afollower portion of a manually operable checker slide slidable in a parallel direction to the axis ofthe said key cylinder, the going sliding movement of the said follower portion begining from the LOCK-position and ending at the START-position being capable of being carried smoothly into effect, while the returning sliding movement of the said follower portion is carried out necessarily through an intermediate stop stage which may be released exclusivelythrough a sliding manipulation ofthe checker slide.

The said elongated camming area comprises a first elongated zone starting from said LOCK-position, a second elongated zone ending at said STARTposition and arranged parallel with each other, and a bridging zone connecting the inner and neighbouring ends ofthe saidfirstand second zones.

The bridging zone represents an inclined wall surface serving for smooth guiding of the said follower portion,from saidfirstto second camming zone and a substantially traversing checker wall for checking at least provisionally the sliding movement of said follower portion.

The manually operable checker slide serves for preventing an occurrence of unwillful and accidental shaft locking.

The checker slide is formed with an enlarged operating end which is exposed outwards from the casing of said steering device and to be manipulated from outside and arranged in such a waythatwhen the checker slide is pulled personally towards the vehicle driver, the said provisionally checked position ofthe slide at the bringing zone ofthecamming area is released.

The bridging zone may preferably be positioned at orin proximityofACC-position.

Or alternatively, the bridging zone may be positioned at OFF-position or in proximity thereof. The inventive device mayfurthercomprise a detent mechanism to inform the driver of the time when the checker slide is moved over the bridging zone by providing a detentfeeling.

The detent mechanism may comprise two mutuallyspaced notches formed on said checker slide and a spring-biased ball mounted on the steering column ofthevehicle, so asto bring the notch or not chesforcooperation with the ball in case ofthedetent mechanism brought into operation.

Or alternatively, the detent mechanism may comprise a resilient pawl integ rally formed on said checker slide and a projection formed on a fixed member and arranged to be slidingly engageable with said resilient pawl during movement ofthe slide. The fixed member may preferably be a cylindrical holderin which said keycylinder is rotatably mounted.

The follower projection of said checker slide may be positioned selectively by the will ofthe vehicle op orator in said first camming zone when said keycylin der assumes any one ofthe "LOCK"-position, "SWITCH OFF"-position and "ACCESSARY SWITCH ON"-position, and in which said projection of said checker slide is positioned in said second caming zone when said key cylinder assumes anyone of "ACCESSARY SWITCH ON"-position, "IGNITION SWITCH ON"-position and "STARTER MOTOR ON"position.

Figure lisa sectional view of a conventional steering lock assembly on a steering column assembly, showing a condition wherein the steering shaft is locked; Figure2 is a section viewtaken along a section line ll-ll of Figure 1; Figure 3 is a partially sectioned elevational view of a steering lock device according to the present invention; Figure 4 is an exploded perspective view of an essential portion ofthe steering lock assembly of the invention; Figure 5is a schematic developed view ofthe guide cam portion formed on the outer surface of a rotatable member; Figure 6is a front view taken in the direction of an arrow VI of Figure 3, wherein, however, control knob 50 has been omitted; and Figure 7 is an exploded perspective view of a modified detent mechanism which is applicable to the steering lock assembly of the invention.

In the following, a detailed description of substantially a preferred embodiment ofthe invention in comparison with an embodiment of a comparative conventional arrangement including partofan automotive steering shaft as an object to be locked and unlocked, will be set forth.

In Figures 1 and 2, numeral 10 represents a steering lock assembly as a whole, which is detatchably mounted on a steering column assembly 12 of an automotive vehicle, not shown.

Numeral 14 denotes a conventional steering shaft and 16 represents a conventional steering column formed into a hollowtubeand arranged in parallel thereto.

Numeral 18 represents a rotatable collar member adapted for being mounted on the shaft 14. A recess 20 is formed into the collar 18.

Steering lock assembly 10 comprises a casing 22 which is rigidly attached at its lower portion to column assembly 12; a key cylinder 24which is rotatably mounted in a stationary and hollowcylindrical holder 21 fixedly attached to casing 22 at its upper portion; and a stationary switch unit 26 positioned in a proximityofthe inner end ofsaid key cylinder 24 and rigidly attached to the casing 22.

A rotatable member 28 is provided between the inner end of key cylinder 24 and the inner and front surface of switch unit 26 and mounted rotatably in the inside space of the casing 22, for controlling the switch unit.

By manual rotation of a mechanical mating key piece K inserted into key reception opening 24a ofthe key cylinder24 and kept in position, as shown in Figure 2,the latter can be rotated as desired, the rotational movement thereof being transmitted through the intermediary of the rotatable inter mediate member 28to theworking part of switch unit 26,which is controlled correspondingly as well known to any person skilled in the art.

The member28 slid onto the inner end ofkeycylin- der24 is formed with a cam portion 28a which is kept in sliding contact with a motion-receiving, cam for lower 30a formed on a vertically reciprocatable slide 30, called "hanger rod", when seeing in Figure 1.

This slide 30 is resiliently urged to move downwards by an urging spring 32 which is confined in the housing 22. The slide 30 is hinged at its lower end with upper end of a locking bolt 34and at 100.

With the rotatable member 28 assuming its specificallyselected angular position as shown in Figure 1, called "LOCK"-position, the lower end of locking bolt 34 is kept in engagementwith recess 20 of collar member 18, thus the steering shaft 14 being held in its locked position for the purpose ofvehicletheft prevention.

Now, turning to Figure 2, a key sensor 36 made in the form of a lever pivotable at 38, is arranged alongside the key cylinder 24 generally at a small lateral distance therefrom and within the inside space of a first lateral hollow projection 22a of casing 22. A second lateral hollow projection 22b acts as a supporting partial socketforthe switch unit 26.

First and outer end 36a of lever 36 is enlarged and bent up laterally, so asto be engageablewith a recess 24bformed on key cylinder24. Second and innerend 36b of lever 36 is slightly curved laterally, so as to engage the hanger rod 30, when occasion may desire.

An urging spring 40 is arranged between the lever 36 and the casing projection 22a, so as to resiliently urgethefirst lever end 36a to move downwards in Figure 2. Therefore, the key K is inserted into keyreception opening of key cylinder 24 as is clearly seen in Figure 2, key sensor 36 is urged to swivel clockwise in such manner as to engage second lever end36bwith hanger rod 30. Thus, hanger rod 30and locking bolt 34 are held in the shaft-unlocking position wherein the lower end of the bolt 34 is held disengaged from the recess 20 on the collar 18. Thus, the steering shaft 14 is kept unlocked so long as the key is operatively engaged with key cylinder 24.However, when the key is drawn outfrom the key cylinder 24, the first end 36a of key sensor 36 is put into the key holeofthecylinder24undertheaction of spring40, thereby disengaging the second end 36b of key sensor36 from hanger rod 30. Thus, in this position, locking bolt 34 is permitted to move towards therein cess 20 ofthe collar member 18 and finally brought into locking engagementwith the latter as shown in Figure 1.

The steering shaft lock assembly having the structure as briefly described above is rather oldfashioned, and has such a grave drawback that, when the key K once inserted into the key cylinder is turned, accidentally or carelessnessly, to the "LOCK"-position or drawn out completelytherefrom during running period of the vehicle, locking bolt34 will be spring-urged downwardly in Figure 1 and finally brought into engagement with the recess 20 on collar 18. Underthecondition,thedrivercould not manipulate the steering handle, not shown, which is naturally attached fixedly to the manipulating steer- ing shaft 14, in anyway, although the vehicle is running. Naturally, such a vehicle running position is very dangerous and a grave traffic accidentwould be invited.

A proposal for dissolving such a drawback is to use a so-called "double action type steering lock" as is disclosed in U.S. Patent No.3,673,829. In this improved steering lock, once the key has been inserted in position into the key cylinder, it is positively prevented from turning together with the key cylinder towards the " LOCK"-position, orfrom being drawn out from the key cylinder, unless a separately provided latch lever has been manually operated for guarantee of preventing occurrence ofthe above dangerous kind steering lock.

Referring further to Figures 3-6, improvements overtheforegoing will be described more in detail.

As clearly seen from Figure 3, the improved lock generally denoted 42 comprises a stationary casing 22' having a substantially same general outside configuration as that denoted 22 shown in the foregoing and is also fixedly attached to a steering column 16 shown in Figure 1. Numeral 44 represents a stationark and substantially cylindrical holderwhich is mounted fixedly in the casing 22', a conventional key cylinder 24' having similar configuration and mech anism tothatshown at 24 in the foregoing and being rotatably mounted in a holder 44. A switch unit 26, preferably an engine key operated one, is mounted in a stationary partial sleeve 22b ofthe casing 22, as in the same way with the foregoing arrangement.

A rotatable member 46 acting as a cam, as inthe foregoing arrangement, is mounted rotatably in unison with key cylinder 24' and between the latter and the switch unit 26, for rotary control of the latter, as in the similar manners before. A manually movable latch member 48 formed into a slide, is mounted in the casing 22', the former appearing also at Figure4 in its perspective view and physically in parallel to the key cylinder. A capped knob 50 is attached onto the outer end of the latch member48 in such a mannerthatthevehicle driver pull or push, asthe case may be, the member 49 upon gripping the knob by his finger's end.

As is best seen in Figure 4, the latch slide 48 is formed at its tip end with a lateral projection 52 which is adapted for acting as a cam follower keptin slidable contact with and thus for cooperating with a cam zone orcamming areaformed on the rotatable member46.

For most clear understanding ofthe cam area, the latter is further shown in Figure5 and in itsdeveloped representation. The cam area comprises a first section 56 and a second section 54 slightly stag- gered from each other; and a junction section 58 bridging together these said both. The said first one serves forthe locking purpose, while the said second oneactsforunlocking purpose,aswillbemorefully described hereinafter.

As seen from Figure 6, stationary cylindrical holder 44 carries at its front surface, several representations such as "LOCK", "OFF", "ACC","ON" and "START", corresponding to respective angular positions of the key cylinder24. It may easily be understood by any person skilled in the artthatthese symbol characters correspond more precisely to "STEERING LOCK", "SWITCH OFF" "ACCESSARY SWITCH ON" and "STARTER MOTOR ON", respectively.

The unlocking cam zone 54 includes the positions forACC-, ON-and STARTfor cooperation with the follower projection 52 or 52'. These positions are effective when the key cylinder 24 or 24' assumes the "AC CESSARY SWITCH ON"-. "IGNITION SWITCH ON"and "STARTER MOTOR ON"-positions,whilethe locking cam zone 56 includes the positions "OFF" (more specifically ACC. OFF)- and "LOCK"-positions adapted for respective cooperation with the follower projection 52, these positions being to be taken when the key cylinder assumes respective angular positions of "ON" (more specifically "ACCESSARY SWITCH ON")-,"OFF" (more specifically "ACCES SARYSWITCH OFF")-, and " LOCK" (more specifically "STEERING LOCK")-position.Thus, the junction or bridging zone 58 may include the position of "ACC".

The inner end of the unlocking cam zone 54 is formed with a substantially laterally extending stopperwall 54a, while the inner end of the iocking cam zone 56 is formed with an inclined wall surface 56a for allowing the follower projection 52 or 52' to pass substantially smoothly. The inclined wall surface may preferably be inclined at about 45 degrees relative to the longitudinal axis ofthe locking cam zone or-section.

It is rather preferable to position these both wall portions 54a and 56a in the range ofjunction section 58.

It is to be noted that when the rotatable member 46 and thus the key cylinder 24, assumes the "LOCKposition, thereby positioning the follower projection 52 or 52' of latch slide 48 or 48', respectively, at the leading end of the locking cam zone 56, the key once inserted in position can be pulled out from the key cylinder with absolute safety.

It is furtherto be noted that when the rotatable member46 is rotated partially in the counter- clockwise direction when seeing from the left hand of Figure 4 and as shown buy a small arrow "A" in Figure 5, and indeed, towards the "STARTER MOTOR ON"position, the follower projection 52 or 52' of latch slide 48 or 48' will move rightwards in Figure Sand comes to contact with the inclined wall portion 56a, thus being allowed to pass substantiallyfreely therealong fortransferring to shift to the unlocking cam zone 54. Thus, the cam followerwill arrive finally at the outer end of the zone 54 where the "START" position exists.

When the rotatable member 46, together with the key cylinder, is rotated in the reverse direction from the "START"-position towards the "LOCK"-position, thecamfollower52Or52'will be provisionally stopped by contacting with the abrupt wall portion at 54a.Atthisstage,thedriverwill pull the slidetowards him. Then, its follower projection 52 or 52' will be shifted forcibly downwards in Figure 5 as shown therein by another small arrow "B" for allowing the latter to shift from the mating unlocking cam track 54 to the locking cam track 56.

A detent feeling producing mechanism or briefly detent mechanism is employed so as to provide the driverorthe like person a detentfeeling during personal manipulation ofthe latch 48. The mechanism comprises mutually spaced, first and second notches 60 and 62 formed atthe major portion of and on the inside longitudinal edge of the latch. Holder44 is formed with a lateral blind hole 66, in which an outwardly urging coil spring 68 is mounted and acting upon a steel ball 64.

With the above mechanism, it is possible to shift, manually the latch or position-control member 48 between the "IN"-position shown in its full lines in Figure 3 and the "OUT"-position shown therein in its phantom lines, and indeed with a reliable detentfeeling. In other words, the said selective "IN"- and "OUT"-positioning of the latch our control member 48 can be assured safely.

In place ofthe foregoing detent mechanism, a slightly modified one such as shown in Figure 7 may be employed.

In this modified type, a resilient pawl 70 is formed integrally at the inside longitudinal edge ofthe latch 48' corresponding to the foregoing member 48, so as to cooperate with a small triangular projection 72 formed on the cylindrical holder 44. During to-andfro sliding movement ofthe latch member 48', the pawl 70 resiliently and frictionally slides overthe triangular projection to provide the driver with a detent feelingsimilartotheforegoing. In this modification, the latch is formed with a similar lateral follower arm 52' as before. In addition, the head knob 50' has a solid cylindrical configuration, so asto provide a possibilityfor more easy drawing-out operation of the latch.

In the following, operation ofthe steering lock device ofthe invention will be described with reference to Figure5. For ease with which the description proceeds, it will be commenced with respect two a condition wherein the key cylinder 24 or 24' assumes the "LOCK"-position. In this condition, the follower projection 52 or 52' ofthe latch slide 48 or48'is placed at the leading end of the locking groove section 56 as shown in FigureS, andthusthe button or cap 50 or 50' of the latch slide assumes the "IN "-position.

When, due to manipulation of the engine key, the key cylinder and thus the rotatable member 46 rotates toward the "STARTER MOTOR ON'-position, the follower projection of the control slide 48 or 48' slides in the locking groove section 56 toward the junction cam section 58 and comes into contact with the inclinedwali surface 56a, resulting in that the pro- jection 52 or 52' is shifted to the unlocking groove section 54. Thus, further rotation ofthe key cylinder in the same direction carries the follower projection to the leading end ofthe unlocking cam section 54.It is thus to be noted that because of the provision of the inclined flat surface 56a the rotation of the key cylindertowardthe "STARTER MOTOR ON"position is permitted irrespective of any positions which the key cylinder assumes prior to that rotation.

When, on the contrary, the key cylinder 24 or 24' is rotated in the reverse direction from the "IGNITION, SWITCH ON " -position for the purpose of stopping the engine, the projection 52 slides in the unlocking groove section 54toward the junction section 58 and comes into contact with the stopperflatwall surface 54a so thatfurther rotation ofthe key cylinder 24 is prevented. In this position, the operation of the engine stops. Thereafter, when the button 50 or 50' of the latch slide is pushed in, the follower projection of the same is shifted with detent feeling to the locking cam section 56.Thus, underthis condition, further rotation ofthe key cylinder toward the LOCK"position is permitted, and when the key cylinder comes finallyto the "STEERING LOCK"-position,the key can be pulled out from the key cylinder. It is to be noted that once the projection 52 or 52' ofthe latch slide 48 is shifted to the locking cam section 56 due to pushing ofthe button 50 or 50', the latch slide is maintained in the shifted or "IN"-position due to the function ofthe detent mechanism. Thus, once the button is pushed in, further rotation of the keycylin- dertoward the "LOCK"-position can be achieved without handling ofthe button.

As was described hereinabove, by the provision of the inclined flat surface 56a in the camming area of the rotatable member46,theturning ofthe keycylindertoward the "STARTER MOTOR ON"-position is permitted directly from any positions which the key cylinder 24 or 24' assumes prior to the rotation. This advantageous function is not expected in the case of the conventional steering lock device so far known, a representative embodiment of which has been illust- rated hereinbefore.

Claims (9)

1. A steering lock device adapted for locking a steering shaft of a wheeled motor vehicle by holding a key cylinder at a certain specifically selected an gular position thereof, the said steering shaft being unlocked by bringing said key cylinderto other positionsthan the said specified one and through a rotat able member operable in unison therewith and oper atively connected with a shaft-locking bar mech anism, said device being characterized bythatsaid rotatable member is formed at its outer peripheral surface with a reciprocatingly double-acting, elongated substantiallyonewaycamming area extending between LOCK-position and START-position and cooperating with a follower portion of a manually op erable checker slide slidable in a parallel direction to the axis of said key cylinder, the going-sliding move ment ofthe said follower portion starting from the LOCK-position and ending attheSTART-position being capable of being carried smoothly into effect, whilethe returning sliding movementofthesaidfol- lowerportion is carried out necessarilythrough an intermediate stop stage which may be released exclusivelythrough a sliding manipulation ofthe checkerslide.

2. Asteering lock device as claimed in Claim 1, wherein said cam area comprises a first elongated zone starting from said LOCK-position, a second elongated zone ending at said START-position and parallel with each other, and a bridging zone connecting the inner and neighbouring ends ofthe said first and second zones.

3. Asteering lock device as claimed in Claim 2, wherein said bridging zone represents an inclined wall surface serving forsmooth guiding ofsaidfollower portion, from said first to second camming zone and a substantially traversing checker wall for checking at least provisionallythe sliding movement of said follower portion.

4. A steering lock device as claimed in Claim 1, wherein said manually operable checker slide serves for preventing an occurrence of unwillful and accidental shaft locking.

5. Asteering lock device as claimed in Claim 3, wherein said checker slide is formed with an enlarged operating end which is exposed outwards from a casing of said steering device and to be manipulated from outside and arranged in such a waythatwhen the checker slide is pulled personally towards a vehicle driver, the said provisionally checked position of the checker slide at the bridging zone of the camming area is released from ailowing the provisional checking of said checked or stopped position.

6. Asteering lock device as claimed in Claim 2, wherein said bridging zone is positioned at or in proximity of ACC-position.

7. Asteering lock device as claimed in Claim 1, further comprising a detent mechanism with which the movement of said manually operated latch slide is brought about with a detent feeling.

8. A steering lock device as claimed in Claim 7, in which said detent mechanism comprises spaced two notches formed in said manually operated latch slide and a spring-biased ball partially disposed in a hole of a steering column of the vehicle and pressed against a notch formed on the said latch slide.

9. A steering lock device substantially as herein before described with reference to and as illustrated in Figures 3 to 7 ofthe accompany drawings.