GB2607081A

GB2607081A - Lock assembly

Info

Publication number: GB2607081A
Application number: GB2107600.5A
Authority: GB
Inventors: Shen Yizhou
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-05-27
Filing date: 2021-05-27
Publication date: 2022-11-30
Also published as: GB202107600D0

Abstract

A lock assembly comprises a lock cylinder having keyway 11 for operating a locking member 51. A lock cylinder shield 20 is moveable, e.g. sliding, from a first position which partially obscures the keyway to prevent insertion of key to a second position which exposes the keyway and permits insertion of a key. In the second position the shield actuates an engagement means 30 preventing rotation of the lock cylinder. The lock cylinder may include a plurality of disc detainer plates 54 with true gate (56, fig.3) for location of side bar (52) and may include a radial groove (57) for abutment with engagement plate 31 of mechanism 30 when shield in second position; engagement plate 31 moved shield 20 via lever 32. Preferably lock includes pin shield (80, fig.7) and vibration generator (91, fig.7) to generate vibrational noise during picking attempt. Also claimed is a key with a gap or notch in the stem to permit rotation of key in shield. Alternatively key could be inserted into lock and shield encompasses an integral/captive key head (71, fig.10)

Description

Lock Assembly The present disclosure comprises a lock assembly, particularly to key locks that require a key to be inserted into a keyway in order to lock/unlock the assembly.

Introduction

Lock assemblies are used to inhibit access to a particular area with some types requiring the user to have a unique key to locate into a keyway that allows the assembly to be unlocked.

There exist a number of variant types of key locks on the market, one of the most common of which is the pin tumbler lock. This type of lock comprises a housing, a rotatable plug therein, an actuator and a plurality of differently sized pin tumblers.

Rotation of the plug actuates the actuator thereby unlocking the mechanism. The pin tumblers are biased using springs to extend into the rotatable plug at different heights which prevents the plug rotating. A key can then be inserted into the keyway that is uniquely profiled to move all the pin tumblers into alignment to define a shear line that allows the plug to rotate.

A problem with this variant of lock is that they comprise several points of attack that allow unauthorised persons to open the lock without the correct key. One common known method is 'bumping', where an incorrect or bump key is placed into the keyway and then forcibly struck with an object, transferring energy to the pin tumblers causing them to jump. By twisting the incorrect key whilst the pin tumblers are floating freely above the plug, it is possible to open the lock.

A disc detainer lock is a variant that is less susceptible to bumping as it utilises a plurality of profiled, rotatable discs in place of the pin tumblers that cannot be 30 bumped in the same fashion.

Each detainer disc rotates independently from one another under the influence of a key that is profiled to each of the internal radii of the disc detainers. The lock mechanism is prevented from rotating by a longitudinal bar known as a 'side bar' which inhibits the rotation of the actuator within a locking assembly. Rotating the key brings a gate (commonly referred to as the 'true gate') in each of the disc detainers into alignment that allows the side bar to drop from the actuator into the discs, the discs in turn can then drive the actuator allowing the lock to be opened.

Whilst disc detainer assemblies are an improvement over pin tumbler locks, they are still vulnerable to being picked. A picking tool is placed into the keyway and used to rotate each of the discs in turn under tension until the side bar is located into the true gate. The user is able to feel a click as the bar partially falls, indicating a gate has been found. Once all the true gates are aligned, the lock can then be opened without using the correct key.

To increase the difficulty of picking disc detainer locks, each of the discs may comprise additional 'false gates' that are also placed around the outer radii, and which are designed to give a similar tactile feel to the user as the true gate when picking but will not allow the side bar to fully drop, thus preventing the lock from opening.

However, experienced lock pickers may be able to decode disc detainer assemblies that comprise false gates using prior knowledge of where such gates may be found with respect to the 'true gate' according to the manufacturers specifications. This then becomes an exercise in testing the various possible combinations until the lock is able to be opened.

It is the aim of the present invention to provide a lock assembly that overcomes or mitigates one or more of the problems addressed above.

Statements of Invention

According to a first aspect of the invention there is a lock assembly comprising, a lock cylinder comprising a lock member, a lock cylinder shield, and an engagement mechanism, wherein the lock cylinder shield is selectively movable between a first and second position and whilst in the second position, the engagement mechanism acts on the lock cylinder to prevent operation of the lock member.

The lock cylinder shield may at least partially obstruct/cover the lock cylinder (e.g. an end thereof) in the first position. The lock cylinder shield may expose the lock cylinder (e.g. an end thereof) in the second position.

According to a second aspect of the invention there is a lock assembly comprising, a lock cylinder comprising a lock member and a keyway for receiving a key to operate the locking member, a lock cylinder shield selectively movable between a first and second position, wherein in the first position, the lock cylinder shield at least partially obstructs the keyway, and in the second position the lock cylinder shield substantially exposes the keyway, an engagement mechanism actuatable to selectively permit or prevent operation of the lock member via the keyway, wherein in the second position, the shield actuates the engagement mechanism into a condition in which it prevents operation of the lock cylinder via the keyway.

The condition of the engagement mechanism which prevents the operation of the lock is dependent upon the position of the lock cylinder shield. This results in the keyway being inoperable by a key or a picking tool whilst being exposed.

Optionally, the engagement mechanism may define a force path between the lock cylinder shield and lock member.

The force path may define a route between the lock cylinder shield and the engagement mechanism, that is actuated by the condition of the lock cylinder shield. The force path may be mechanical, such that work is imparted directly or indirectly from the lock cylinder shield to the engagement mechanism.

Alternatively, the path may comprise electrical components to control the engagement mechanism in response to the position of the lock cylinder shield.

Optionally, the engagement mechanism may comprise a plurality of members to provide a force path between the lock cylinder shield and the lock member.

Optionally, the engagement mechanism may comprise an engagement member.

Optionally, the engagement member may be movable within the lock cylinder, e.g. to interfere selectively with one or more lock element of the lock cylinder.

Optionally, the engagement member may be slidable within the lock cylinder.

Optionally, the lock member may be immobilised from movement when the engagement member is engaged with the lock member.

Optionally, the lock member may be rotatable within the lock cylinder.

Optionally, the lock member may comprise one or more lock elements.

Optionally, the engagement member may engage with the lock member, e.g. the one or more of the lock elements thereof, to prevent movement of the lock 20 member.

Optionally, the one or more lock elements may be detainer discs.

Optionally, at least one of the one or more lock elements, e.g. the detainer discs 25 thereof, may comprise an abutment member.

Optionally, all of the one or more lock elements, e.g. the detainer discs thereof, may comprise an abutment member.

Optionally, the abutment member may selectively engage with the engagement mechanism, e.g. the engagement member thereof, to prevent movement/rotation of the lock elements, e.g. the detainer discs thereof.

Optionally, the selective engagement between the engagement mechanism, e.g. the engagement member thereof, and the lock member, e.g. the lock elements or the detainer discs thereof, prevents movement/rotation of the lock member in a first direction, which may be either the unlocking or locking direction. Alternatively, the lock member may be prevented from movement/rotation in both directions.

Optionally, the engagement mechanism may comprise an intermediate member. The engagement member may be separate from or form part of the intermediate member.

Optionally, the intermediate member may provide a force path from the lock cylinder shield to the engagement member.

Optionally, the intermediate member may be moveable within the lock cylinder.

Optionally, the intermediate member may be rotatable/pivotable, e.g. in response to movement of the lock cylinder shield. The intermediate member may be rotatable about an axis within the lock cylinder.

Optionally, movement of the lock cylinder shield between the first and second position may actuate the intermediate member.

Optionally, actuation of the intermediate member may take the form of rotation about an axis.

The intermediate member may comprise an arm.

Optionally, the intermediate member may comprise a first member for engagement with the engagement member.

Optionally, the first member may be a first arm.

Optionally, the intermediate member may comprise a second member for engagement with the lock cylinder shield.

Optionally, the second member may be a second arm.

Optionally, the first and second arms may be angularly offset, e.g. perpendicular.

Optionally, the lock cylinder shield may comprise a protruding member.

Optionally, the lock cylinder shield protruding member may selectively engage with the second arm of the intermediate member.

Optionally, the engagement between the lock cylinder shield, e.g. the protruding member thereof, and the intermediate member, e.g. the second arm thereof, is gradual/continuous. The load/moment applied by movement of the lock cylinder shield may increase as the lock cylinder shield moves from the first to the second position.

Optionally, engagement between the lock cylinder shield, e.g. the protruding member thereof, and intermediate member, e.g. the second arm thereof, actuates the intermediate member to rotate.

Optionally, the engagement member comprises an opening for receiving a portion of the first member of the intermediate member, which may be the first arm.

Optionally, actuation of the intermediate member may move the engagement member into engagement with the lock member.

Optionally, the first member, e.g. the first arm thereof, of the intermediate member 30 may drive the engagement member into engagement with the lock member.

Optionally, the intermediate member may comprise a ledge.

Optionally, moving the lock cylinder shield from the second to first position may bring the protruding member and ledge into engagement.

Optionally, engagement between the protruding member of the lock cylinder shield 5 and ledge actuates the intermediate member.

Optionally, actuation of the intermediate member may cause the intermediate member to rotate.

Optionally, the rotation of the intermediate member may cause the engagement member to disengage from the lock member.

Optionally, the rotation of the intermediate member, e.g. the first arm thereof, may disengage the engagement member from the lock member.

Optionally, the lock cylinder shield may comprise a first plate. Optionally, the lock cylinder shield may comprise a second plate that is rotatable with respect to the first plate.

Optionally, the lock cylinder shield, e.g. the second plate thereof, may comprise at least one key receiving formation suitable for receiving an engagement portion of a key.

Optionally, the lock cylinder shield, e.g. the second plate thereof, may comprise a plurality of key receiving portions, each suitable for receiving an engagement portion of a key.

Optionally, the lock cylinder shield, e.g. the second plate thereof, may comprise a handle which may be configured to rotate a key in the keyway.

Where the lock cylinder shield comprises a handle, the key does not need to comprise an integral handle. As such, the key may be substantially comprised from a key stem wherein the portion of the key that engages with the key receiving portion of the lock cylinder shield being construed as the key engagement portion. Rotation of the lock cylinder shield handle then actuates the key, e.g. the key stem thereof, causing it to rotate in the keyway.

Alternatively, the lock cylinder shield, e.g. the second plate thereof, may be configured to receive a key, e.g. the engagement portion thereof, comprising a key handle which may be able to rotate the key stem in the keyway.

Where the key comprises a key handle and key stem, the lock cylinder shield may be configured such as to allow for rotation of the key stem in the keyway by the key handle, whilst the lock cylinder shield is in the first position (e.g. when the keyway is substantially covered).

Optionally, the first plate comprises an opening, suitable for allowing an engagement portion of a key to engage with the second plate.

Optionally, the second plate can engage/rotate with a key in the keyway while the lock cylinder shield is in the first position.

Optionally, the key receiving formation comprises a radial groove and may be suitable for receiving a portion of a key handle.

Optionally, the lock cylinder shield, e.g. the second plate thereof, comprises a groove on a major face, suitable for receiving a portion of a key handle.

Optionally, the lock assembly may be a disc detainer locking assembly. Optionally, the lock assembly may be a pin tumbler assembly or any other type of common locking assembly.

Optionally, the lock assembly, e.g. the lock member thereof, may comprise a plug, wherein the plug may be rotatable within the lock assembly.

Optionally, the lock cylinder shield may comprise a pin-shield. Optionally, the pin-shield may locate within a plug.

Optionally, the pin-shield may comprise a key receiving formation. Optionally, the key receiving formation may be a slot.

The pin-shield locates in the keyway and further obstructs the insertion of an item such as a key or picking tool. Only items that are shaped to correspond with the key receiving formation of the pin-shield are able to enter the keyway, further reducing the chances of the lock assembly being picked.

Optionally, the plug may comprise an abutment member.

Optionally, the plug may comprise an abutment member for engagement with the engagement mechanism, e.g. the engagement member thereof.

Where the plug comprises the abutment member, engagement with the engagement mechanism will render the lock inoperable. The plug may comprise the abutment member in place of the locking members thereof.

Optionally, the pin-shield may be selectively engageable with the lock cylinder shield, e.g. the protruding member thereof.

Optionally, the pin-shield may move in unison with the lock cylinder shield as it moves between the first and second position.

The pin-shield may be rotationally moveable in the lock assembly within the plug. When rotated into a specific orientation, the pin-shield engages with the lock cylinder shield, e.g. the protruding member thereof, such that pin-shield moves in unison with the lock cylinder shield. This may prevent as brute force attack on the lock assembly, specially the lock cylinder shield by defining an force path.

According to a third aspect of the invention there is a lock assembly comprising: a lock cylinder comprising a lock member and a keyway for receiving a key to operate the lock member, a key being suitable for locating in the keyway, a lock cylinder shield selectively movable between a first and second position, wherein in the first position, the lock cylinder shield at least partially obstructs the keyway, and in the second position the lock cylinder shield substantially exposes the keyway, wherein the lock cylinder shield comprises a key receiving formation for engaging a key whilst in the keyway and/or wherein the lock cylinder shield is rotatable with a key in the first position.

The arrangement allows a key to be rotated in the keyway, whilst being covered by the lock cylinder shield, such that both the key and keyway are not accessible to the user when the lock assembly is being locked and/or unlocked.

Optionally, The lock cylinder shield may comprise multiple key receiving formations for engaging with a plurality of portions of the key, e.g. the key stem and/or bridge portion and/or key handle thereof.

According to a fourth aspect of the invention, there is provided a key arranged to cooperate with the locking cylinder shield of any preceding aspect when in the first position.

According to a fifth aspect of the invention there is a key comprising, a key stem, wherein the key stem defines a longitudinal axis through the key,wherein there is a gap/discontinuity between the key stem and a handle along the longitudinal axis.

In operation the key may be inserted into the keyway when it is exposed. The lock assembly may comprise a lock cylinder shield that moves into the gap/discontinuity such as to cover the keyway with the key within. The handle may be suitable for actuating the key.

Optionally, the handle may form part of the lock assembly and is configured to actuate the key, e.g. the key stem thereof.

The gap/discontinuity between the key stem of the key and a handle allows the lock assembly to be locked and/or locked while the keyway is covered.

Where the handle forms part of the lock assembly (e.g. is not integral to the key), the key is substantially comprised of a key stem that is placed into the keyway.

The engagement portion of the key engages with the lock assembly and movement/rotation of the handle actuates the key, e.g. the lock formation thereof, to lock and/or unlock the lock assembly.

Optionally, the handle may form part of the key wherein the gap/discontinuity separates the handle and key stem along the longitudinal axis.

Optionally, the key may comprise a bridge portion that is offset from the longitudinal axis and connects the key stem to the handle.

Where the handle forms part of the key, the gap/discontinuity provides a space for the lock assembly to occupy, such as to obstruct the keyway from view. As the handle is integral to the key, rotation of the handle also serves to rotate the key stem in the keyway. The bridge portion connects the key stem and key handle for as to rotationally fix all parts of the key.

Optionally, the key may comprise an engagement portion that may engage with the lock assembly key receiving formation.

Optionally, the key may comprise a plurality of engagement portions, which may be located on the key stem and/or the bridge portion and/or key handle.

The engagement portion(s) provides a connect/engagement point with the lock assembly, which may be the lock cylinder shield or pin-shield. The engagement portion(s) may be located on the key stem and/or bridge portion and/or key handle (where the handle is integral with the key). Where the key comprises a bridge and/or handle, there may be a plurality of key receiving formations for engaging with multiple points of the key.

According to a sixth aspect of the invention there is a lock assembly comprising, a lock assembly, and a vibration generator located within the lock assembly, wherein the vibration generator is configured to add vibrational noise to increase the difficulty of picking the lock assembly.

Optionally, the vibration generator may be rotatable within the lock assembly.

Optionally, the vibration generator may comprise an insert which is profiled to fit into the inner surface of the housing.

Optionally, the vibration generator may press against the inner surface of the housing or against an insert.

Optionally, the vibration generator may comprise a ball bearing, which may be biased to press against the assembly and/or insert using a biasing member, e.g. a spring.

Optionally, there may be a plurality of vibration generators, e.g. ball bearings.

Optionally, the inner surface of the housing or inner surface of the insert is textured or uneven in the region where the at least one vibration generator is located.

Optionally, the vibrations generated by rotation of the vibration generator may obfuscate vibrations generated by rotation of the lock mechanism.

As will be appreciated, the lock cylinder shield will prevent the lock assembly from being picked or decoded when covering the keyway. Similarly, the engagement member will also inhibit the rotation of the disc detainers when the keyway is exposed, thus also preventing picking and decoding.

Any of the optional or essential features defined in relation to any one aspect of the invention above may be applied to any further aspect, wherever practicable. Those optional feature combinations have not been explicitly repeated only for conciseness.

Detailed Description

Workable embodiments of the invention are described in further detail below, by way of example only, with reference to the accompanying drawings, of which: Figure 1 shows a three-dimensional view of a lock assembly comprising a lock cylinder shield in a first position Figure 2 shows a three-dimensional view of a lock assembly comprising a lock cylinder shield in a second position.

Figure 3 shows a partially exploded view of a lock cylinder and a disc detainer lock member thereof.

Figure 4 shows a cross-section of the lock assembly with the lock cylinder shield in the first position without a key Figure 5 shows a cross-section of the lock assembly with the lock cylinder shield in the second position with a key.

Figure 6 shows a cross-section of the lock assembly with the lock cylinder shield in the second position with a key.

Figure 7 shows an exploded three-dimensional view of the pin-shield and plug.

Figure 8 shows a side-view of an example of a key to be used with the lock 25 assembly.

Figure 9 shows a bottom-view of an example of a key to be used with the lock assembly.

Figure 10 shows a three dimensional view of a further embodiment of a lock assembly.

Figure 11 shows a cross-section of an alternative embodiment comprising a pin tumbler assembly in the second position.

Figure 12 shows a cross-section of an alternative embodiment comprising a pin tumbler assembly in the first position.

Figures 1-6 show a lock assembly according to a preferred embodiment of the invention. In the embodiment shown the lock assembly is a disc detainer type lock, although it should be understood that this is provided as an example only and that the invention is not limited to this particular type of lock mechanism. Any lock assembly with locking elements capable of operation with the shield mechanism described herein may be suitable.

The lock assembly 10 comprises a lock cylinder 40 forming the assembly housing, comprising a barrel portion 41 for mounting/housing a lock member 50, and an undercarriage portion 42 for housing an engagement mechanism (30, figure 4).

The front of the lock assembly comprises a lock cylinder shield 20 that is selectively moveable (relative to the lock cylinder 40) between a first and second position shown in figures 1 and 2 respectively.

In the first position, the lock cylinder shield 20 denies access to the keyway 11 meaning that a key cannot be inserted into the assembly. The lock cylinder 20 (i.e. the upper portion 22 thereof) substantially obstructs the open end of the keyway 11. To access the keyway 11, the lock cylinder shield 20 must be moved into the second position as shown in figure 2. However, it can be seen that a small opening/cut-out 23 in the profile of the shield does provide a very restricted opening into the keyway even when the shield is in the closed/first position. This small slot like opening exposes only a minor region of the keyway and is insufficient for insertion of a conventional key.

As will be explained below, the lock is inoperable when the lock cylinder shield 20 is in the second/open position, i.e. the key will not open the lock despite the keyway 11 being exposed. This inversely associates the accessibility of the keyway 11 to the operability of the lock.

When the key is inserted into the keyway 11, the lock cylinder shield 20 must be moved back into the first position for the lock assembly to become operable. The key can then be rotated whilst the keyway 11 is covered. Further details of the associated mechanism and shield will be described below.

Lock Cylinder Shield The lock cylinder shield 20 comprises first 21 and second 22 plates, the second plate 22 being rotatable with respect to the first 21. The key engages with the second plate 22 in the first position and is rotatable with respect to the first plate 21 due to their geometries.

The second plate 22 may comprise one or two key receiving formations which engage with complimentary engagement portions of a key.

A first key receiving formation 23 is a groove/cut-out located on the peripheral edge of the second plate 22. The formation 23 may be defined as a radial detent with a depth that spans a minority of the radius/diameter of the plate 22. The groove may extend in a circumferential direction to a greater extent than the radial depth of the groove.

The shape and size of the groove in this example corresponds to an engagement portion (68, figure 7) of a key such that when the key and second plate are engaged, the second plate remains rotatable with respect to the first plate 21.

A second key receiving formation 24 is located on the major face of the second plate 22, e.g. the outwardly-facing or front face of the plate 22. The formation is a groove or slot shaped to receive a portion of a key. In this example, the formation 24 has a shape that corresponds to an engagement portion (66, figure 7) located on the key handle.

The first 21 and second 22 plates are arranged in a co-planar and/or flush fashion.

The second plate 22 is contained within the profile of the first plate and/or substantially surrounded by the first plate.

Arched arms 25 extend from the first plate 21 and substantially cover the radial edge of the second plate 22. A discontinuity between the arched arms 25 forms an opening 26, e.g. that aligns with the formation 23, such as to allow for the key and the key receiving formations to engage.

The second plate 22 is received and held within the arched arms 25 of the first plate in the example shown.

Lock Mechanism The lock member 50 is a disc detainer mechanism and is shown in greater detail in figure 3. It comprises an actuator 51, a side bar 52, a plurality of spacers 53 & disc detainers 54. The mechanics of disc detainer locks will be known to the skilled person and therefore will only be discussed briefly for conciseness.

When in a locked configuration, the side bar 52 locates within a groove (not shown) of the barrel portion 41 and a first channel 59 of the actuator 51. This prevents movement (specifically, rotation) of the actuator 51 within the lock assembly 10.

The detainer discs 54 and spacers 53 are rotatable within the actuator under the influence of a key, and each comprise a true gate 56 in the form of a radial groove that is shaped to receive the side bar 52 when in alignment with the actuator first channel 59. Only when all the true gates of both the detainer discs and spacers are in alignment will the side bar fall into the channel defined by the collection of true gates 56. The actuator is then rotatable in the lock cylinder such that the locking pawl 55 actuates the latch mechanism (not shown) to unlock the assembly.

Around the outer periphery of the detainer discs are a plurality of false gates (e.g. castellations/detents) which are only shallow enough to allow the side bar 52 to partially fall into, but provides a similar tactile feel to any would-be lock picker as when the side bar 52 falls into the true gate 56. The false gates therefore increase the difficulty of lock picking and decoding the lock assembly.

The detainer discs 54 and spacers 53 additionally comprise an abutment member 57 in the form of a radial groove which engages with the engagement mechanism (described below) through the actuator second channel 58, when the lock cylinder shield 20 is moved into the second position. As should be clear, when the lock cylinder shield 20 is in the second position, the engagement mechanism 30, detainer discs 54 and actuator 51 are rotationally immobilised and the lock assembly is thus inoperable.

In the embodiment shown, the abutment member 57 prevents rotation in both the locking and unlocking directions however, the abutment member 57 may alternatively comprise a ledge or protrusion such as to prevent rotation in a single (locking or unlocking) direction.

Engagement Mechanism Figures 4-6 shows the cross-section through the lock assembly 10 during the unlocking process. The lock cylinder shield 20 is shown in the first position in figure 4 where the keyway 11 is covered. The undercarriage portion 42 houses the engagement mechanism 30 which is comprised from an engagement member 31 and an intermediate member 32. The purpose of the engagement mechanism is to define a force path between the lock cylinder shield 20 and lock member 50, e.g. the detainer discs 54 thereof, such that the operability of the lock member 50 is dependent upon the position of the lock cylinder shield 20.

The engagement member 31 is selectively engageable with the abutment members 57 of the detainer discs 54 via the second channel 58 of the actuator 51.

The intermediate member comprises orthogonal first 33 and second 34 arms which are rotatable about a pivot point 35. The first arm locates within a slot 36 of the engagement member 31.

A protruding member 27 located on the lock cylinder shield 20 engages with the second arm 34 of the intermediate member 32 as the lock cylinder shield 20 moves to the second position, as shown in figure 4. The engagement actuates the first arm 33 to rotate about the pivot point 35 which in turn drives the engagement member 31 into engagement with the detainer discs 54. The turning moment force increases as the lock cylinder shield moves 20 towards the second position.

When the lock cylinder shield 20 is in the second position shown in figure 5, a key can then be inserted into the keyway 11. The engagement between the engagement member 31 and the detainer discs 54 prevents the detainer discs from rotating and thus the lock is inoperable.

Moving the lock cylinder shield 20 back into the first position moves the engagement member 31 from the disc detainers 54. This allows the disc detainers to rotate under the influence of the key 60 and the lock assembly 10 can then be unlocked.

Figure 6 shows that the intermediate member 32 comprises a ledge 37 (e.g. in the form of a small projection facing the shield). As the lock cylinder shield 20 moves back into the first position, the protruding member 27 and ledge 37 come into engagement which rotates the first arm 33, driving the engagement member 31 out of engagement from the disc detainers 54.

The Plug, Pin Shield and Vibration Generator Figure 7 shows an expanded view of the plug 90, pin shield 80, vibration generator 91 and lock cylinder 40 only. It should be understood that although these features are shown together in this embodiment, the pin shield, vibration generator and plug could each be implemented individually with or without the other features and are shown in combination with one another only for conciseness.

The plug comprises a vibration generator 91 located around its outer surface in the form of a ball bearing that is biased to press against the inner surface of the barrel portion using a spring. As the plug rotates under the influence of a key or picking tool, the ball bearing generates vibrations against the housing which obscures any vibrations generated by the side bar engaging with the true or false gates. This further increases the difficulty of picking. The inner surface of the barrel portion may comprise textured or uneven portions 92 to further obscure the vibrations..

As should be appreciated, the embodiment is provided as one example of how vibrational noise could be generated. Other embodiments can be envisaged that provide an equivalent function. For example, the vibration generator could be one or more free ball bearings that moves freely inside a compartment of the plug that generates vibrations as the plug rotates. Alternatively, a ratchet and pawl could be provided such that clicking is generated by the pawl as the plug rotates.

Alternatively the plug may comprise an insert or collar that can be inserted into the barrel portion wherein the inner surface of the insert/collar is textured or uneven.

The plug then rotates in the insert. This arrangement would allow the plug and insert to be used with any of a manufacture's existing models of lock assemblies with little or no modification to the cylinder lock housing. The pin-shield 80 is located within the plug 90 via a slot and obstructs the keyway 11. The pin-shield 80 may be referred to as an inner or secondary shield. The pin-shield can further increase the difficulty of picking.

The pin-shield is selectively engageable with both the rotatable plug and lock cylinder shield. The plug comprises a slot that is shaped to receive the pin-shield when the lock cylinder shield is in the first position.

The pin-shield rotates with the plug On the lock cylinder). When rotated into a specific orientation, the pin-shield selectively engages with the protruding member of the lock cylinder shield and able to move in unison therewith, such that upon moving the lock cylinder shield into the second position, the pin-shield will be moved out of the plug and into the undercarriage housing.

If the plug is not correctly orientated when the lock cylinder shield is moved to the second position, the pin-shield will not be engaged with the protruding member. As such, the pin-shield will obstruct the keyway.

The Key Figures 8 & 9 shows the key 60 to be used in conjunction with the lock assembly comprising a key stem 61, a bridge portion 62 and handle 63. The key stem 61 defines a longitudinal axis along the key 60. Locking formations 64 extend from the key stem 61 and are profiled to engage with at least a portion of the inner radii of the disc detainers 54 such that each of the true gates 56 can be brought into alignment with the side bar 52.

There is a gap 65 (e.g. a discontinuity or offset) between the key stem 61 and handle 63 along the longitudinal axis. The key stem 61 and handle 63 are connected via the bridge portion 62 which is axially offset from the longitudinal axis. The bridge portion comprises a first engagement portion 68 that corresponds to the size and shape of the key receiving formation 23 located on the radial edge of the second plate 22 of the lock cylinder shield 20. The second engagement portion (67, best shown in figure 9) of bridge portion corresponds to the key receiving formation slot (81, see figure 7) located on the pin-shield 80. The key comprises a third engagement portion 66 located on the key handle 63 that corresponds to the key receiving formation 24 located on the major face of the second plate 22.

The bridge portion 62 may be described as being generally U-shaped, thereby defining the gap 65 therein. Any edge portion of the U-shaped profile may be used to define an engagement portion of the key for engaging the shield in use.

The gap 65 is suitable for receiving the second plate 22 of the lock cylinder shield such as to cover the keyway 11 even when the key stem 61 inside. The geometry of the key 60 and lock cylinder shield 20 allows both parts to remain rotatable when the lock cylinder shield 20 is in the first position.

Operation To unlock the lock assembly 10 in use, the user approaches the lock assembly with the lock cylinder shield 20 substantially covering the keyway 11. The user than has to move the lock cylinder shield 20 into the second position as shown in figure 2, exposing the keyway 11. If the plug was in the correctly rotated orientation, such that the of the pin-shield was engaged with the protruding member, the pin-shield is drawn into the undercarriage portion of the lock cylinder as the lock cylinder shield moves into the second position. If the plug is not correctly orientated, the pin-shield will remain in the plug, thereby blocking the keyway.

When the lock cylinder shield 20 moves into the second position, the engagement 15 mechanism 30 is actuated such as to drive the engagement member 31 into the abutment members 57 located on the detainer discs 54, thus preventing the operation of the lock.

The user then inserts the key and moves the lock cylinder shield 20 back into the first position, such that the second plate 22 of the lock cylinder shield 20 occupies the gap portion 65 along the longitudinal axis of the key 60. The key receiving formations located on the second plate contact the engagement portions of the key. The engagement member 31 is driven from the disc detainers 54 as the lock cylinder shield 20 is moved back into the first position such that the disc detainers 54 can rotate. The protruding member moves the pin-shield upwardly back into the plug-slot of the rotatable plug. The pin-shield comprises key-receiving formations that correspond to engagement portions of the key. If the incorrect key is inserted, such that the engagement portions do not match, the pin-shield will only partially extend into the plug-slot, rotationally fixing the plug to the lock assembly thus preventing the key from turning and opening the lock. A further consequence of the pin-shield being only able to extend partially into the plug-slot is that the protruding member will prevent the lock cylinder shield moving fully back into the first position. The engagement member will therefore not disengage from the disc detainers and as such the disc detainers remain immobilised.

Once the key is fully engaged with the lock cylinder shield and pin-shield, the user then rotates the key handle 63 which is rotatable with the second plate 22. The locking formations 64 on the key aligns the true gates 56 on the disc detainers 54 such that the side bar 52 falls from the lock cylinder, allowing the actuator 51 to rotate. The lock pawl 55 then actuates a latch mechanism (not shown) or the like to open the lock.

It will be understood that when the lock cylinder shield is in the first position, the pin-shield can only be moved back into the plug when the plug-slot is in the correct orientation. The geometry of the key, specifically to the lock formations thereof will ensure that the correct alignment corresponds to a position to where the disc detainers are in the locked configuration. This prevents the key from being withdrawn from the lock assembly when the assembly is unlocked.

Figure 10 shows a preferred second embodiment of the lock assembly 70. The lock cylinder, engagement mechanism and lock member all operate the same way as described above. In this embodiment, the handle 71 is integrally formed with the second plate 72 of the lock cylinder shield instead of the key. The key comprises a stem portion 73 with lock formations and the gap/discontinuity (between the handle) which are substantially the same as the first embodiment. The bridge portion 74 is located at the key stem end and is comprised of a rod that is substantially orthogonal to the longitudinal axis of the key. The lock cylinder shield comprises a key receiving formation 75 that corresponds to the size and shape of the bridge portion. It should be appreciated from the figure that the key receiving formation will engage with the key, specifically the bridge portion thereof, when the lock cylinder shield is moved into the first position. Rotating the handle actuates the key to rotate in the keyway.

The operation of the second embodiment is similar to that of the first embodiment. The user manually moves the lock cylinder shield into the first position, thereby exposing the keyway and inhibiting the disc detainers from rotating via the engagement mechanism.

A key, which comprises a key stem and bridge portion is inserted into the lock.

The user then moves the lock cylinder shield back into the first position such that the bridge portion engages with a key receiving formation located on the inner face of the second plate. The key is then rotatable via the second plate handle to open the lock.

Other embodiments are envisioned, for example a third preferred embodiment may comprise a hybrid of the first and second embodiments, wherein the key handle is selectively detachable from the key and locatable into a groove on the major face of the second plate, and the key stem is locatable into the keyway. After the lock assembly has been unlocked/locked, the handle can be disengaged from the lock cylinder shield and used to grasp the key stem from the keyway and be hung on a key ring.

An alternative lock assembly is shown in figures 11 and 12. In this embodiment, the lock assembly comprises a pin tumbler locking mechanism in place of the disc detainers discussed previously.

Figure 11 shows the pin tumbler assembly with the lock cylinder shield 20 in the second position. The lock cylinder shield 20 comprises first 21 and second 22 plates with the second plate 22 being rotatable with respect to the first 21 as with the previous embodiments. The second plate 22 comprises key receiving formations 23, 24 on opposing major faces to engage with the key stem 61 and key handle 63 respectively. In this embodiment, the engagement mechanism 30 is a unitary piece which largely resembles the intermediate member of the previous embodiments with an protrusion on the first arm which is defined to be the engagement member 31 of this embodiment. The engagement mechanism 30 defines a direct force path to the abutment member 57 located on the plug 90.

In operation, the user moves the lock cylinder shield 20 into the second position and inserts the key stem 61 into the keyway 11 (shown in figure 11). The locking formations 64 on the key 60 move the driver pins and key pins into the correct alignment with the shear line such that the plug can be rotated. The mechanics of pin tumbler locks will be known to the skilled person. The movement of the lock cylinder shield 20 into the second position brings the protruding member 27 into engagement with the engagement mechanism 30, thereby actuating the engagement mechanism 30 such as to drive the engagement member 31 into engagement with the abutment member 57. This renders the lock inoperable in the same way with the previous embodiments.

The user then moves the lock cylinder shield 20 back into the first position as shown in figure 12, bringing the key receiving formation 23 located on the inner face of the second plate 22 into engagement with the key stem 61. The user then inserts the key handle 63 into the opposing major face of the second plate, such that the key stem 61, second plate 22 and key handle 63 are rotationally fixed. The movement of the lock cylinder shield 20 also brings the protruding member 27 into engagement with the ledge 37 of the engagement mechanism 30, driving the engagement member 31 from the abutment member in the same way as the previous embodiments. The lock is now operable such that the key may be rotated.

In alternative embodiments, the engagement mechanism may be integrated with the lock cylinder shield, such as to provide a direct force path to the lock member.

The engagement mechanism may be electronically controlled such that the engagement member selectively engages with the detainer discs upon receiving a signal generated from a controller in response to the position of the lock cylinder shield. In the embodiments described, all of the detainer discs comprise abutment members to engage with the engagement member however, it should be understood that only one disc needs to comprise an abutment member to prevent operation of the lock in the second position. As such in alternative embodiments, only one of the disc detainers may comprise an abutment member.

Claims

Claims 1. A lock assembly comprising, a lock cylinder comprising a locking member and a keyway for receiving a key to operate the locking member, a lock cylinder shield selectively movable between a first and second position, wherein in the first position, the lock cylinder shield at least partially obstructs the keyway, and in the second position the lock cylinder shield substantially exposes the keyway, an engagement mechanism actuatable to selectively permit or prevent operation of the lock member via the keyway, wherein in the second position, the shield actuates the engagement mechanism into a condition in which it prevents operation of the lock cylinder via the keyway.
2. A lock assembly according to claim 1, wherein the engagement mechanism defines a force path between the lock cylinder shield and lock member.
3. A lock assembly according to claims 1 or 2, wherein the engagement 20 mechanism comprises an engagement member.
4. A lock assembly according to claim 3, wherein the engagement member is selectively engageable with the lock member such as to prevent operation of the lock member.
5. A lock assembly according to claim 4, wherein the lock member is immobilised from movement when the engagement member is engaged with the lock member.
6. A lock assembly according to any of the previous claims, wherein the lock member comprises one or more lock elements.
7. A lock assembly according to claim 6 and any of claims 3-5, wherein at least one of the one or more lock elements comprises an abutment member for selective engagement with the engagement member.
8. A lock assembly according to claim 7, wherein the one or more lock elements are prevented from movement when the engagement member is engaged with at least one of the abutment members.
9. A lock assembly according to any of the previous claims, wherein the 10 engagement mechanism comprises an intermediate member.
10. A lock assembly according to claim 9 and any of claims 3-8, wherein the intermediate member provides a force path from the lock cylinder shield to the engagement member.
11. A lock assembly according to claim 10, the intermediate member is rotatable/pivotable about an axis within the lock cylinder.
12. A lock assembly according to any of claims 10-11, wherein the intermediate 20 member comprises a first arm for engagement with the engagement member.
13. A lock assembly according to any of claims 10-11, wherein the intermediate member comprises a second arm for engagement with the lock cylinder shield.
14. A lock assembly according to any of the previous claims, wherein the lock cylinder shield comprises a protruding member.
15. A lock assembly according to claim 14 when appended to claim 13, wherein the protruding member is selectively engageable with the second arm of the intermediate member.
16. A lock assembly according to claim 15, wherein the engagement between the protruding member and the second arm is gradual/continuous, such that the load/moment applied by movement of the lock cylinder shield increases as the lock cylinder shield moves from the first to the second position.
17. A lock assembly according to claims 15 or 16, wherein engagement 5 between the protruding member and second arm actuates the intermediate member to rotate.
18. A lock assembly according to claim 17, wherein actuation of the intermediate member moves the engagement member into engagement with the lock member.
19. A lock assembly according to claims 12 and 18, wherein the first arm of the intermediate member drives the engagement member into engagement with the lock member.
20. A lock assembly according to any of claims 14-19, wherein the intermediate member comprises a ledge, wherein moving the lock cylinder shield from the second to first position brings the protruding member and ledge into engagement.
21. A lock assembly according to claim 20, wherein engagement between the protruding member and ledge actuates the intermediate member, causing it to rotate.
22. A lock assembly according to claim 21, wherein the rotation of the intermediate member causes the engagement member to disengage from the lock member.
23. A lock assembly according to claim 22, wherein the rotation of the intermediate member causes the first arm to drive the engagement member out of 30 engagement from the lock member.
24. A lock assembly according to any of the previous claims, wherein the lock cylinder shield comprises a first and second plate, wherein the second plate is rotatable with respect to the first plate.
25. A lock assembly according to claim 24, wherein the second plate comprises at least one key receiving formation, suitable for receiving an engagement portion of a key, the key receiving formation preferably being a groove on a major face or radial edge.
26. A lock assembly according to any of the previous claims, comprising a pin-shield in the keyway comprising a key receiving formation slot that engages with an engagement portion of a key.
27. A lock assembly according to any of the previous claims, wherein the lock assembly is a disc detainer assembly.
28. A lock assembly according to any of the previous claims, comprising a vibration generator, configured to add vibrational noise to the lock assembly upon movement of the lock member and is preferably rotatable within the lock assembly.
29. A lock assembly according to claim 28, wherein the vibration generator is at least one ball bearing that abuts against a surface of the lock assembly,
30. A lock assembly according to claims 28 or 29, wherein the surface of the lock assembly where the vibration generator is located is textured or uneven such as to obfuscate vibrations generated by rotation of the locking member.
31. A key arranged to cooperate with the locking assembly according to any preceding claims, comprising a key stem, wherein the key stem defines a longitudinal axis through the key, and wherein there is a gap/discontinuity between the key stem and a handle along the longitudinal axis.
32. A key according to claim 31, wherein the handle is integral to the key, and wherein the key further comprises a bridge portion that is offset from the longitudinal axis and connects the key stem to the handle.
33. A key according to claim 31, where the handle is integral to the lock cylinder shield.
34. A key according to claim 25 and/or 26 and any of claims 31-33, wherein the key comprises at least one engagement portion, suitable for engagement with the at least one key receiving formations.
35. A key comprising, a key stem, and at least one engagement portion, wherein the at least one engagement portion is suitable for engagement with the lock cylinder shield according to any of the previous claims.