GB2480911A

GB2480911A - A locking device wherein a shield protects the locking member from external magnetic influences

Info

Publication number: GB2480911A
Application number: GB1108812A
Authority: GB
Inventors: Daisuke Nomichi
Original assignee: Tokai Rika Co Ltd
Current assignee: Tokai Rika Co Ltd
Priority date: 2010-05-31
Filing date: 2011-05-25
Publication date: 2011-12-07
Anticipated expiration: 2031-05-25
Also published as: GB2480911B; GB201108812D0; JP2011246092A

Abstract

A locking device 1 has a locking member (e.g. a locking bar / bolt) 201a arranged to move between a locked and unlocked position and a shield 21 which serves to prevent an external magnetic field from influencing movement of the locking member. Ideally the locking device is provided to lock a steering wheel of a vehicle, the locking device preferably being key operated K and comprising a rotor 112 and tumblers. The magnetic shield / shroud 21 protects the locking bolt by dispersing and redistributing the magnetic field. Preferably the shield/ guard is made of a magnetic metal material, e.g. steel. As such, a thief attacking the lock with a magnet will not be successful in unlocking the vehicle. An independent claim relates to a steering locking device wherein a shield intersects and blocks an extended line of the locking bar movement direction. (This prevents a direct axial line between a magnet and the locking bar.)

Description

LOCKING DEVICE

This invention relates to a locking device and, in particular, but not exclusively to a steering lock device.

Locking devices, such as those used to prevent the theft of cars or other vehicles, are a common way to obstruct criminal activity.

As a vehicle antitheft system, a locking device such as a steering lock device restricts movement of a steering wheel in the absence of an ignition key. For example, JP-A-2004-3 14745 discloses a steering lock device that, for the purpose of downsizing, a key cylinder is disposed parallel to and close to (as partially overlapped with) a locking bar for locking a steering column.

Known locking devices have the disadvantage of limited efficiency in preventing an underlying locking mechanism from being forced from a locked position into an unlocked position and/or rendered inoperable.

The present invention seeks to provide a locking device having advantages over known locking devices and which can be operative to prevent the theft of property such as a car, a van, a truck, a motorhome or any other type of vehicle.

According to one embodiment of the present invention, there is provided a locking device comprising a locking mechanism having a locking member operative to move between a locked and an unlocked position and a shield operable to prevent an external magnetic field from influencing movement of the locking mechanism between the locked and unlocked positions.

Preferably, there is provided a locking device wherein the locking mechanism includes a turnable case member and a locking member such as a bar or bolt movable relative to movement of the turnable case member such that the locking member can only be moved when the case member is turned.

In particular, the locking device can include a turnable case member operable to receive a key which may be configured to be unique to the turnable case member.

Preferably, the bar can be movable in a direction parallel to the axis of rotation of the turnable case member.

Yet further, the shield can be arranged to cover at least a part of the outer wall of the locking mechanism.

Preferably, the shield can further comprise a side that covers at least a part of an outer wall of the locking mechanism.

Preferably, the locking device can be provided with a shield comprising at least in part, a magnetic material which can be arranged to induce an extraneous

magnetic field.

Advantageously, the shield can further comprise an opening including a conical counterbore, and arranged to be mounted to the case member via a flush bolt inserted into the opening.

Advantageously, the flush bolt can comprise a one-way bolt arranged to rotate only when fastened in the flush bolt.

Preferably, there is provided a locking device wherein a one-way bolt includes a head with a groove for operative engagement with a driver only when fastening the bolt, preferably in a clockwise direction, and a tapered groove gradually shallowing, preferably in a counterclockwise direction from the groove.

Advantageously, the flush bolt can be secured such that, when the shield is completely fitted to the locking mechanism, the head thereof is located under a top of the conical counterbore to be held at a position lower than a top surface of the shield. Such an arrangement can make it very difficult, if not impossible, to inhibit attack on the flush bolt.

In one arrangement of the invention the magnetic material can comprise a magnetic metal material.

Preferably, the magnetic material can comprise at least one of a cold rolled steel (SPCC), a hot rolled steel (SPHC), or carbon steel (S25C to S55C).

The magnetic material can be distributed in the shield proximal to the movable bar and possibly at higher concentrations than the other areas of the locking device.

This can advantageously serve to concentrate the induction of the magnetic field at a location proximate to the movable bar.

Preferably, the shield can have a front side portion disposed opposite a front end face (ie., an end face opposite a steering column) of the movable locking member in the direction of movement of the locking member, use of a magnet at the front side portion for moving the locking member can be more effectively prevented.

The invention can also provide for a steering lock device comprising a case member enclosing a rotor to be turned by using a key and a movable bar to move in a direction parallel to a rotation axis of the rotor; and a shield covering a part of an outer wall of the case member and comprising a magnetic metal material, wherein the shield further comprises a side that covers the outer wall of the case member and intersects with an extended line in a direction of moving the movable bar.

The invention is described further hereinafter, by way of example only, with reference to the accompanying drawings in which: FIG IA is a side view showing a steering lock device in an embodiment of the invention, wherein a part of a bracket for fixing a steering column is shown partially broken; FIG.1B isa bottom view showing the steering lock device of the embodiment; FIG.2 is a longitudinal cross sectional view showing an internal structure of the steering lock device in FIG.1A; FIG.3 is a cross sectional view showing a locking bar and a steering column of the steering lock device in FIG.1A; FIG.4 is a perspective view showing a shield fitted to the steering lock device in FIG.1A; FIG.5A is a top view showing an attachment part of the shield of the embodiment; and FIG.5B is a cross sectional view showing the attachment part in FIG.5A.

According to an embodiment of the present invention there is provided a locking device which may be used in vehicles such as those operable with a steering wheel. The locking device may be used to lock the steering wheel when the vehicle is not in use such as when it is parked at night or in a car park at a place of work or anywhere else where the vehicle may be vulnerable to theft or intrusion.

The locking device may comprise a locking mechanism which may comprise turnable case member and an attached bar which is movable relative to a turning of the case member when the turnable case member is turned by, say, a key or any other device provided to permit access to the locking device. The movement of the bar may be, possibly advantageously, in a parallel direction but it will be appreciated that the bar may be movable in a direction orthogonal to the turn or any other direction considered to be, possibly advantageous or desirable for a particular application.

The locking mechanism may also comprise an outer wall which is covered, at least in part, by a shield. The shield may comprise a side that covers at least part of the outer wall of the locking mechanism and can provide increased protection for the locking mechanism.

According to an embodiment of the invention, the locking device, which may be a steering lock device is equipped with a shield that is formed of a magnetic material, possibly a metal, for covering nearly or at least a part of the the entire outer wall of a steering lock portion (or a case member). Therefore, even when a perpetrator tries to illegally draw a movable bar from the "LOCK" position into the "UNLOCK" position for releasing the steering lock function (i.e., allowing the rotation of a steering column) by creating an extraneous magnetic field using a strong magnet, the magnetic field is induced by the shield such that it does not act on the locking bar. Thus, the illegal act using the magnet may be prevented. Especially, possibly advantageously, when the shield has a front side portion disposed opposite a front end face (i.e., an end face opposite the steering column) of the movable bar in the direction of moving back the movable bar, the illegal act using the magnet at the front side portion for moving back the locking bar by the magnetic force can be more effectively prevented.

A steering lock device in an embodiment of the invention will be described below by reference to the drawings.

FIG.lAis a side view showing a steering lock device 1 in an embodiment of the invention, wherein a part of a bracket 102 for fixing a steering column 80 of a vehicle is shown partially broken. FIG.1B is a bottom view showing the steering lock device 1. The steering lock device 1 comprises a key portion 10, a steering lock portion 20, an interlock unit 30, and an ignition switch unit 40.

FIG.2 is a longitudinal cross sectional view showing an internal structure of the steering lock device 1. A case 101 of the steering lock device I may be integrally formed by using a metal material such as zinc die-cast etc for at least a part of the case. The case 101 is fitted with a key cylinder 110 having a cylinder 111, and a rotor 112 rotatably accommodated in the cylinder 111. The rotor 112 of the key cylinder 110 has a key hole 112a which may be internally formed in the axis direction and into which a key K is inserted.

The material forming the case may also be paramagnetic or consist of organic magnetic material such as a plastic magnet. An example may be the organic magnetic material PANiCNQ which is a combination of emeraldine-based polyaniline (PANi) and tetracyanoquinodimethane (TCNQ).

Plastic magnets are possibly advantageous in that they are lighter and more flexible than traditional magnets.

The rotor 112 accommodates plural tumblers 113, which are elongate and movable in the radial direction (i.e., vertical direction in FIG.2) of the rotor 112.

When the key K is not inserted, the tumblers 113, protrude from the outer periphery of the rotor 112 to be engaged with an inner periphery of the cylinder 111, so that the rotor 112 is restricted from turning. When the regular key K is inserted into the key hole 112a, the tumblers 113 are correspondingly engaged with a grooved end face of the key K such that the tumblers 113 are all retracted inside the outer periphery of the rotor 112. This allows the rotor 112 to be turned by hand.

A slide piece 114 is disposed movably in the radial direction at a front lower part of the rotor 112. The outer surface of the slide piece 114 is formed in the same curvature as the outer periphery of the rotor 112 such that the rotor 112 and the slide piece 114 can be turned together inside the key cylinder 110. The slide piece 114 is restricted from moving toward the center of the rotor 112 since an end portion thereof contacts a part of the key K while the key K is inserted into the rotor 112.

An antilock lever 115 as an elongated movable member is disposed under the key cylinder 110 such that it is parallel to the center axis of eh key cylinder 110 and turnable around a shaft at a middle part thereof. On the front side of the antilock lever 115, a front end portion 115a is formed curved toward the slide piece 114.

On the back side of the antilock lever 115, a back end portion 115b is formed as being engageable with an engaging protrusion 203a of a slider 203 as described later. The antilock lever 115 is applied an elastic force for pushing the front end portion 115a toward the slide piece 114 (Le, in the rise direction) by a spring (not shown) etc. When the rotor 112 is at the "LOCK' position or the key K is removed from the key cylinder 110, the elastic force serves to raise the front end portion 11 5a of the antilock lever 115 and to descend the transponder controlling device lib such that the antilock condition is released (i.e., steering lock-allowed state).

Acam shaft 116 is connected to a back shaft 112b of the rotor 112. The cam shaft 116 has a cylindrical outer tube 116a and a cylindrical inner tube 116b which are integrated as being connected together at the front end. The back shaft 112b of the rotor 112 is fitted onto the inner periphery of the inner tube 116b of the cam shaft 116, and the back end of the inner tune 116b protrudes from the case 101 and connected to the ignition switch unit 40. Thus, the ignition switch unit 40 can be operated via the cam shaft 116 when the rotor 112 of the key cylinder 110 is turned by the regular key-K.

A torsion spring 117 is accommodated in a space between the outer tube 116a and the inner tube 116b of the cam shaft 116. One end of the torsion spring 117 is engaged to the outer tube 11 6a of the cam shaft 116. When the rotor 112 in the key cylinder 110 reaches the "ON" position by turning the key K, the other end of the torsion spring 117 is engaged to the case 101 such that the spring force applies to the cam shaft 116 in the direction allowing the key operation to return to the "ON" position from the "START" position.

A cam surface 116c slidable with a follower 203a of the slider 203 formed under the outer tube 116a of the cam shaft 116.

The steering lock portion 20 has a locking bar 201, a compression spring 202, and the slider 203. The locking bar 201 is shaped like a bar and formed of a rigid metal, and a tip portion thereof can move forward and back to and from the steering column 80 side. The locking bar 201 is always applied a spring force in the direction moving forward from the case 101 by the compression spring 202 accommodated in the case 101.

In the case 101, a groove 201b is formed at the upper part of the locking bar 201, and the lower part of the slider 203 is engaged with the groove 201 b. The upper back surface of the slider 203 contacts a back inner wall 101 c of the case 101 such that the locking bar 201 is prevented from being removed from the case 101.

The slider 203 has the follower 203a integrally formed at the top of the slider 203 for contacting and following the cam surface 11 6c of the cam shaft 116 as described earlier. Also, the slider 203 has an engaging protrusion 203b formed at the front top of the slider 203 for engaging with the back end portion 11 5b of the antilock lever 115 as described earlier.

FIG.3 is a cross sectional view showing the locking bar 201 and the steering column 80 of the steering lock device I in FIG.1A. The bracket 102 is shaped like a semi-arc (or arch) and one end thereof is supported as being openable via a hinge shaft 102a by a hinge block portion lOib of the case 101. The steering column 80 can be fixed to the steering lock device 1 such that the bracket 102 is opened, the steering column 80 is fitted in the case 101, the bracket 102 is closed, and the other end of the bracket 102 is fixed to a boss block portion lOla via a bolt 103.

As shown in FIG.3, at the "LOCK" position where the locking bar 201 moves forward to the steering column 80 side, a tip portion 201 a of the locking bar 201 is inserted and engaged into a concave portion 82a of a spline boss 82 fitted to a steering shaft 81. Thus, the steering shaft 81 is restricted from turning. At the "UNLOCK" position where the locking bar 201 moves back from the steering column 80 side, the tip portion 201 a of the locking bar 201 is not engaged with the spline boss 82. Thus, the steering shaft 81 is released from the turning restriction.

According to the construction of the steering lock portion 20 as described above, when the key K is removed from the key hole 112a, the slide piece 114 is not restricted from turning and raised by the front end portion 11 5a of the antilock lever 115, where the back end portion 115b of the antilock lever 115 descends.

Therefore, the engaging protrusion 203b of the slider 203 cannot be engaged with the back end portion 115b, the locking bar 201 moves forward to the "LOCK" position by the elastic extensible force of the compression spring 202, and the top back face of the slider 203 engaging the groove 201 b of the locking bar 201 contacts the back inner wall lOlc of the case 101. Thus, the locking bar 201 is held at the "LOCK" position.

When the regular key K is inserted into the key hole 112a and the rotor 112 is turned from the "LOCK" position to the "ACC" position, the slide piece 114 moves to the position where the outer surface thereof corresponds to the outer surface of the rotor 112, such that it pushes down the front end portion liSa of the antilock lever 115 and the back end portion 115b of the antilock lever 115 is thereby raised.

In this case, the cam shaft 116 turns according as the rotor 112 turns, the slider 203 and engaging protrusion 203b at the front side thereof move forward together with the follower 203a contacting and following the cam surface 11 6c of the cam shaft 116, and the locking bar 201 engageable with the slider 203 at the groove 201b moves back to the "UNLOCK" position. Then, when the rotor 112 reaches the "ACC" position, the engaging protrusion 203b engages with the back end portion 11 5b of the antilock lever 115 so as to retain the slider 203 at that position and to retain the locking bar 201 engaging with the slider 203 at the "UNLOCK" position.

Thus, after the key K is turned to the "ACC" position, the antilock is set in order to prevent the erroneous activation of the steering lock.

FIG.4 is a perspective view showing an example shield 21 fitted to the steering lock device 1. The shield 21 may be integrally formed by a casting process such as a pressure casting of an iron material as a magnetic metal material such as a cold rolled steel (SPCC), a hot rolled steel (SPHC), carbon steel (S25C to S55C).

As shown in FIG.4, the shield 21 is formed into a shape for covering nearly the entire outer wall surface of the steering lock portion 2.

In detail, the shield 21 may have at least four-side shielding portions that include a front side portion 211 for covering the front wall portion of the case 101 intersecting with an extended line in the direction of moving back the locking bar 201 from the steering column 80, an inclined bottom portion 212a and a horizontal bottom portion 212b covering the bottom wall of the case 101 under the locking bar 201, a left side portion 213 covering the left wall of the case 101 viewed from the insertion direction of the key K, and a right side portion 214 covering the right wall of the case 101. The shield 21 may be opened at the top side (i.e., the opposite side to the key portion 10) and at the back side (i.e., the opposite side to the steering column 80) except the four-side shielding portions.

According to an embodiment the steering lock device 1 with the shield 21 of the embodiment, the shield 21 may be formed of the magnetic material for covering nearly the entire outer wall or at least a part of the outer wall of the steering lock portion 20. Therefore, even when a perpetrator tries to draw the locking bar 201 to the "UNLOCK" position by externally using a strong magnet, the magnetic force is induced by the shield 21 is such that it does not act on the locking bar 201. Thus, the illegal act using the magnet can be prevented by the shielding effect of the shield.

The material making the shield is not limited to magnetic metal materials, paramagnetic materials or organic metal materials such as a plastic magnet. An example of a plastic magnet is PANiCNQ which is a combination of emeraldine-based polyaniline (PANi) and tetracyanoquinodimethane (TCNQ) may be used.

Plastic magnets are, possibly advantageously, lighter and more flexible than traditional magnets.

The material may be a composite consisting of a number of materials and, possibly advantageously, a magnetic material may be distributed in higher or lower concentrations proximal or distal to the locking mechanism.

Especially, in the steering lock device 1 of the small type that the direction of moving the locking bar 201 is parallel to the rotation axis of the rotor 112 as in the embodiment, since the shield 21 has the front side portion 211 on the extended line in the direction of moving back the locking bar 201, the illegal act by using the magnet at the front side portion 211 can be more effectively prevented.

Furthermore, a bolt hole 21b composing an attachment part 22 for attaching the shield 21 to the case 101 may be formed in the left side portion 213 and the right side portion 213 of the shield 21. FIG.5A is a top view showing the attachment part 22 of the shield 21 and FIG.5B is a cross sectional view showing the attachment part 22.

The shield 21 may be fixed to the case 101 by an one-way flush bolt 25 inserted into the bolt hole 21b from outside. At the top side of the bolt hole 21b, a conical counterbore 21a may be formed that has a depth increasing according as it comes close to the center.

According to the attachment structure of the shield 21 of the embodiment, as shown in FIG.5B, the one-way flush bolt 25 may be secured such that, when the shield 21 is completely fitted to the case 101, the head of the one-way flush bolt 25 gets under the top of the conical counterbore 21a to be held at a position deeper than the surface of the shield 21. Thereby, it may be possible to inhibit the illegal attack to the one-way flush bolt 25 using a bar etc. Thus, the illegal removal of the shield 21 can be prevented.

In addition, the top of the one-way flush bolt 25 is formed having a vertical groove 25a engageable with a driver only when clockwise fastening the bolt 25, and a tapered (or sloped) groove 25b gradually shallowing counterclockwise from the vertical groove 25a. Therefore, it is very difficult to release and remove the bolt 25 from the shield 21 by using a regular tool. The illegal act such as removing the shield 21 by unfastening the bolt 25 may be effectively prevented.

Although the invention has been described with respect to the specific embodiments for complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art which fall within the basic teaching herein set forth.

As used herein, the terms "comprises', "comprising", "includes", "has", "having" or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, a method, article or apparatus. Further, unless explicitly stated to the contrary, "or" refers to an inclusive or and not to an exclusive or. For example, a condition A or B is satisfied by any one of the following: A is true(or present) and B is false (or not present), A is false(or not present) and B is true(or present), and both A and B are true (or present).

In addition, use of the "a" or "an" are employed to describe elements and components of the invention. This is done merely for convenience and to give a general sense of the invention. The description should be read to include one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise.

The scope of the present disclosure includes any novel feature or combination of features disclosed therein either explicitly or implicitly or any generalisation thereof irrespective of whether or not it relates to the claimed invention or mitigate against any or all of the problems addressed by the present invention. The applicant hereby gives notice that new claims may be formulated to such features during prosecution of this application or of any such further application derived therefrom.

In particular, with reference to the appended claims, features from dependent claims may be combined with those of the dependent claims and features from respective independent claims may be combined in any appropriate manner and not merely in specific combinations enumerated in the claims.

Claims

CLAIMS: 1. A locking device comprising: a locking mechanism having a locking member arranged to move between a locked and an unlocked position; and a shield operable to prevent an external magnetic field from influencing movement of the locking member between the locked and unlocked positions.
2. A locking device according to Claim 1, wherein the locking mechanism includes a turnable case member and a locking member comprising a bar operable to move responsive to a turning of the turnable case member.
3. A locking device according to Claim 2, wherein the turnable case member is arranged to receive a key.
4. A locking device according to Claim 2, wherein the bar is movable in a direction parallel to the axis of rotation of the turnable case member.
5. A locking device according to Claim 4, wherein the shield is arranged to cover at least a part of an outer wall of the locking mechanism.
6. A locking device according to Claim 5, wherein the shield further comprises a side that covers at least a part of the outer wall of the locking mechanism.
7. A locking device according to any one or more of the preceding claims wherein the shield comprises, at least in part, a magnetic material.
8. A locking device according to Claim 7, wherein the magnetic material is a magnetic metal material.
9. A locking device according to Claim 8, wherein the magnetic material comprises at least one of a cold rolled steel (SPCC), a hot rolled steel (SPHC), or carbon steel (S25C to S55C).
10. A locking device according to Claim 7, 8 or 9, wherein the magnetic material in the shield is distributed proximal to the movable locking member at higher concentrations than the other locations.
11. A locking device according to any one or more of the preceding claims, wherein the shield further comprises a bolt hole including a conical counterbore, and is mounted to a case member via a flush bolt received into the bolt hole.
12. A locking device according to Claim 11, wherein the flush bolt comprises an one-way bolt that is allowed to rotate only when fastened in the bolt hole.
13. A locking device according to Claim 11 or 12, wherein the one-way bolt includes a head with a groove for operative engagement with a driver only when fastening the bolt, and presents a gradually shallowing tapered groove for attempted removal of the bolt.
14. A locking device according to Claim 11, 12 or 13, wherein the flush bolt is secured such that, when the shield is fitted to the locking mechanism, a head thereof is located under a top of the conical counterbore to be held at a position lower than the surface of the shield.
15. A locking device according to Claim 1, wherein the shield has a front side portion disposed opposite a front end face of the movable bar in the direction of moving the movable bar.
16. A steering lock device, comprising: a case member enclosing a rotor to be turned by using a key and a locking bar to move in a direction parallel to a rotation axis of the rotor; and a protector covering a part of an outer wall of the case member and comprising a magnetic metal material, wherein the protector further comprises a side that covers the outer wall of the case member and intersects with an extended line in a direction of moving the locking bar.
17. A locking device substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.