GB2607867A

GB2607867A - A cylinder lock and a cam for a cylinder lock

Info

Publication number: GB2607867A
Application number: GB2107800.1A
Authority: GB
Inventors: Gardiner Robin
Original assignee: Titon Hardware Ltd
Current assignee: Titon Hardware Ltd
Priority date: 2021-06-01
Filing date: 2021-06-01
Publication date: 2022-12-21
Also published as: WO2022253684A3; WO2022253684A2; GB202107800D0

Abstract

A cylinder lock for a door having an internal side and an external side, comprises a body with an internal and external sides when the lock in installed on a door, and comprises a cam 7 for actuating a locking means of the door, the cam 7 being arranged between the internal and external sides of the body. The cam 7 comprises a peripherally extending rounded or chamfered edge 8 on its outer circumferential surface, the rounded or chamfered edge 8 facing towards the external side of the body of the cylinder lock. The chamfer or rounded edge is intended to prevent an attack gripping the cam if the outer cylinder lock has been attacked and removed. The chamfer may be at any angle offset from perpendicular. There may be lines of weakness within the outer cylinder barrel. Also claimed is a cylinder lock with a body and a cam and means for attaching the cam to the cylinder lock upon attack from the external side of the door. Methods of manufacture are also disclosed.

Description

A cylinder lock and a cam for a cylinder lock The present invention relates to a cylinder lock for a door. The invention also relates to a 5 cam for a cylinder lock.

Cylinder locks comprise a body having two portions: an internal side, configured to be arranged on an internal side of a door, and an external side, configured to be arranged on an external side of a door. The internal side of a door that which is interior to a room or space and the external side of a door is that which is exterior to a room or space to which the door provides access. A cam is arranged for rotation between the two sides and the cam is configured such that rotation of the cam actuates an internal locking mechanism of the door in which the cylinder lock is to be installed. A bridge portion adjoins the internal and external sides of the cylinder lock and is sometimes integrally formed with both sides of the cylinder lock. There are many different types of cylinder lock, but two types are the double barrel type and the thumbturn type. Double barrel cylinder locks have a rotatable barrel provided within each of the internal and external sides of the body for causing rotation of the cam upon receipt of a key within a keyslot provided in each barrel, whereas thumbturn locks have a barrel, with a keyslot, on the external side of the lock body but have a thumbturn mechanism, for operation by a user without needing a key, provided on the internal side of the lock body.

Known cylinder locks are vulnerable to a type of attack by an intruder in which a clamping or grasping tool is used to grasp the external side of the lock body and in which the external side of the cylinder lock, or a portion thereof, is snapped off. This type of attack can be referred to as a snapping intrusion attack and is intended to snap the cylinder lock body at or near the bridge portion in order to provide access to the cam so that the cam can be manually removed to provide access to the locking mechanism of the door. Various designs of lock have been attempted to prevent this type of attack, or at least to make it more difficult to perform or to increase how much time it would take an attacker to do. Many of these design focus on providing a pre-weakened portion of the external body so that the lock body snaps at a position which does not provide easy access to the cam when attacked in this way. However, attackers have become familiar with these designs and have developed sophisticated techniques to circumvent them and are thereby still able to access the cam for removal for unlocking the door. Thus, there is a need to provide a more secure cylinder lock which more effectively hinders access to the locking mechanism of the door.

The present invention aims to alleviate at least to a certain extent at least one of the problems of the prior art. Alternatively, the invention aims to provide a more secure cylinder lock which prevents or further inhibits an attack by an intruder.

According to a first aspect of the present invention, there is provided a cylinder lock for a door having an internal side and an external side, the cylinder lock comprising: a body having an internal side configured to be arranged on the internal side of the door when the cylinder lock is installed in the door; and the body also having an external side configured to be arranged on the external side of the door when the cylinder lock is installed in the door; a cam for actuating a locking means of the door, the cam being arranged between the internal side of the body and the external side of the body; and wherein the cam comprises a peripherally extending rounded or chamfered edge on an outer circumferential surface of the cam, the rounded or chamfered edge facing towards the external side of the body of the cylinder lock.

As used herein, the terms "internal" and "external" mean whether that feature is intended to be on or towards or closest to the inside (or interior) or outside (or exterior) of the room or building or space the door provides access to when the cylinder lock is installed in a door.

For example, a door lock is generally intended to prevent access to the room on the internal side of the door. The terms "internal" and "external" are not intended to mean contained within that component/feature itself, for example the phrase "internal end of the barrel" is the end of the barrel which is configured to be arranged towards the side of the door which is facing or closest to the inside of the room or building or space to which the door provides access. Thus, the terms "internal" and "external" could be replaced herein by the terms "internal-side" and "external-side" respectively. The cylinder lock may be a euro cylinder lock.

A peripherally, or circumferentially, extending rounded or chamfered edge on an outer circumferential surface of the cam, the rounded or chamfered edge facing towards the external side of the body of the cylinder lock has been found to be particularly advantageous as a method of preventing or inhibiting removal of the cam from the cylinder lock during a snapping intrusion attack from the external side of the door. Such a feature provides an anti-grip functionality to the cam to prevent or inhibit the cam being grasped by a gripping or clamping tool, such as a set of pliers, as used by an attacker from the external side of the lock. This is because the rounded or chamfered edge provides a slip plane such that the clamping action of the gripping or grasping tool (e.g. set of pliers causes) the nose/teeth of the clamping or grasping tool to slide or slip off of the end of the cam when a clamping force is applied by the tool to the rounded or chamfered surface, thereby preventing the tool/pliers from obtaining a secure grip on the cam such that the rounded or chamfered edge prevents or inhibits removal of the cam from its attachment on the internal side of the cylinder lock. Such a feature is particularly advantageous when the attack involves breaking off a portion or the entirety of the external side of the cylinder lock so as to expose the cam for attack. Such snapping intrusion attacks may involve breaking of the bridge portion of the body between the external and internal sides of the body as this may generally be the weakest portion of the body, or at an area of predetermined weakness where, for example, the cylinder lock comprises a breakaway slot forming a sacrificial portion of the body for breaking away during an external-side snapping intrusion attack. Optionally the cylinder lock may be a Euro Cylinder Lock.

Optionally, the internal side of the body comprises an internal lock actuator configured so 15 as to be actuatable from the internal side of the door when the cylinder lock is installed in the door. The internal lock actuator may be configured to actuate a differ pin and tumbler assembly.

Optionally, the external side of the body comprises an external lock actuator configured so 20 as to be actuatable from the external side of the door when the cylinder lock is installed in the door. The external lock actuator may be configured to actuate a differ pin and tumbler assembly.

Optionally, the internal lock actuator is rotatably received within the internal side of the body of the cylinder lock and/or the external lock actuator is rotatably received within the external side of the body of the cylinder lock. For example, the internal and external lock actuators may be rotatably received within an axially-extending throughbore provided in each of the internal and external sides of the body.

Optionally, the cam comprises an external end and an internal end corresponding to the external side and internal side of body of the cylinder lock respectively, and wherein the peripherally extending chamfered or rounded edge is provided at or towards the external end of the cam. Optionally, the rounded or chamfered edge is arranged so as to face towards the external surface of the door when the cylinder lock is installed in the door.

Optionally the external and internal ends of the cam are axial ends of the cam, for example arranged at opposite ends of the rotational axis of the cam or the longitudinal axis of the cam.

Optionally, the internal lock actuator and/or the external lock actuator are selectively rotationally couplable and decouplable with the cam. Thus, the internal lock actuator and/or external lock actuator may be configured to actuate the cam

S

Optionally, the cylinder lock is configured such that, when the external lock actuator is rotationally coupled with the cam, the internal lock actuator is rotationally decoupled from the cam.

Optionally, the external lock actuator comprises an external barrel rotatably received within the external side of the body. Optionally the external barrel is operably couplable to the cam for actuating the cam when the external barrel is coupled to the cam. Optionally, the external barrel is rotatably-received within an axially-extending bore in the external side of the body.

Optionally, the external barrel comprises an external key slot which is configured to actuate the external lock actuator.

Optionally, the internal lock actuator comprises an internal barrel rotatably-received within the internal side of the body. Optionally the internal barrel is operably couplable to the cam 20 for actuating the cam. Optionally, the internal barrel is rotatably-received within an axially-extending bore in the internal side of the body.

Optionally, the internal lock actuator comprises an internal key slot which is configured to actuate the internal lock actuator. For example, the key slot of the internal lock actuator may optionally be configured to actuate the internal lock actuator when a key is inserted into the internal key slot from the internal side of the door. For example, the internal barrel may optionally comprise the internal key slot.

Optionally, the external side of the body comprises a breakaway-slot for forming a predetermined area of weakness such that a snapping intrusion attempt causes the body to snap at the predetermined area of weakness. Thus, the breakaway-slot defines the sacrificial portion of the external body such that the sacrificial portion is caused to breakaway from the remainder of the body during a snapping intrusion attack. Optionally, the external side of the body comprises a predetermined area of weakness such that a snapping intrusion attempt causes the body to snap at the predetermined area of weakness.

Optionally, the cam is configured to rotate about a cam rotation axis between a first rotational position corresponding to a locked configuration of the door and a second rotational position corresponding to an unlocked configuration of the door. Optionally, the cam rotation axis is substantially parallel with the longitudinal axis of the cylinder lock body.

The terms cam axis", "cam rotation axis" and "cam rotational axis" are interchangeable herein.

Optionally, the cylinder lock comprises a drive member configured to provide a rotational drive path between the internal lock actuator and the cam to rotate the cam between the 10 first and second rotational positions thereof.

Optionally, the drive member is an internal clutch configured to selectively form a rotational drive path between the internal lock actuator and the cam to rotate the cam between the first and second rotational positions thereof. Optionally, the internal clutch is slidably received within the internal side of the body so as to be slidable along an axis parallel to the cam rotation axis. Optionally, the cylinder lock further comprises an internal clutch configured to selectively form a rotational drive path between the internal lock actuator and the cam such that the internal lock actuator is selectively operably connected to the cam for actuating the cam.

Optionally, the internal clutch has an internal-clutch-engaged configuration or position in which the internal clutch is rotationally coupled with the cam, and an internal-clutchdisengaged configuration or position in which the internal clutch is rotationally decoupled from the cam; wherein the cylinder lock is selectively configurable between the internal-clutch engaged configuration or position and the internal-clutch disengaged configuration or position. In the internal-clutch-engaged configuration or position, the rotation of the internal clutch causes rotation of the cam.

Optionally, the cam has an internal side arranged towards the internal side of the body, and 30 wherein the internal clutch comprises one or more internal-clutch locking formations configured to engage with corresponding locking formations provided in the internal side of the cam. Optionally the locking formations may be axially extending.

Optionally, the internal clutch is rotationally coupled or couplable to the internal lock actuator 35 such that, when the internal clutch is in the internal-clutch engaged configuration or position, rotation of the internal lock actuator causes rotation of the cam.

Optionally, the cylinder lock comprises biasing means arranged to provide a biasing force to bias the internal clutch into the internal-clutch-engaged configuration or position. Optionally, the biasing means may be an internal clutch biasing means.

Optionally, the biasing means comprises an spring or bias arranged within the internal side of the cylinder body. The biasing means may be referred to as an internal clutch biasing means. Optionally, the spring may be an internal clutch spring. Optionally the internal clutch spring or bias is arranged in the axially-extending bore of the internal side of the cylinder body in which the internal barrel is rotatably received.

Optionally, the cylinder lock further comprises an external clutch configured to selectively form a rotational drive path between the external lock actuator and the cam to lock and unlock the locking means of the door.

Optionally, the cylinder lock has an external-clutch engaged configuration or position in which the external clutch is rotationally coupled to the cam, and an external-clutchdisengaged configuration or position in which the external clutch is rotationally decoupled from the cam; wherein the cylinder lock is selectively configurable between the externalclutch-engaged configuration or position and the external-clutch-disengaged configuration or position. Optionally, the cylinder lock is configured to be in the external-clutch-engaged configuration or position when a key is inserted into the key slot of the external barrel.

Optionally, the external barrel comprises an external key slot and wherein insertion of a key into the external key slot causes the cylinder lock to adopt the external-clutch engaged configuration or position.

Optionally, the cylinder lock is configured such that insertion of a key into the external key slot causes the external clutch to be pushed or pulled into, or maintained in, engagement with the cam such that the external clutch becomes rotationally coupled with the cam.

Optionally, the biasing means is configured to indirectly bias the external clutch out of engagement with the cam.

Optionally, the cylinder lock is configured such that removal of the key from the external key 35 slot causes the cylinder lock to adopt the external-clutch disengaged configuration or position.

Optionally, the cam has an external side arranged towards the external side of the body, wherein the external clutch comprises one or more external-clutch locking formations configured to engage with corresponding locking formations provided in the external side of the cam.

S

Optionally, the external clutch is rotationally coupled to the external barrel such that, when the external clutch is in the external-clutch engaged configuration or position, rotation of the external barrel causes rotation of the cam.

Optionally, the cylinder lock is configured such that, when the cylinder lock is in the externalclutch-engaged configuration or position, the cylinder lock is also in the internal-clutchdisengaged configuration or position.

Optionally, the cylinder lock is configured such that, when the cylinder lock is in the internal-15 clutch-engaged configuration or position, the cylinder lock is also in the external-clutchdisengaged configuration or position.

Optionally, the external clutch is biased out of locking engagement with the cam. Optionally the bias of the internal clutch biasing means is such that, unless a key is inserted into the external barrel of the external lock actuator, the internal clutch biasing means overcomes the bias of the external clutch such that the external clutch is biased out of engagement with the cam by the internal clutch biasing means.

Optionally, the external clutch comprises a base and an axially-extending finger, optionally 25 wherein the finger is biased away from the base, optionally wherein the finger is a sprung-finger biased away from the base.

Optionally, the external clutch spring is configured to bias the sprung-finger away from the base. For example, the sprung-finger is biased axially away from the base.

Optionally, the external clutch spring biases the sprung-finger into engagement with the cam.

Optionally, the cam has an aperture extending axially therethrough.

Optionally, the aperture of the cam is configured to receive the sprung-finger of the external clutch such that when the external clutch is in the external-clutch-engaged configuration or position, the internal clutch is held out of engagement or rotational coupling with the cam by the sprung-finger of the external clutch.

Optionally, the aperture of the cam is configured to receive an axially-extending projection 5 of the internal clutch such that, when the internal clutch is in the internal-clutch-engaged configuration or position, the external clutch is held out of engagement with the cam by the axially-extending projection of the internal clutch.

Optionally, the axially-extending projection of the internal clutch protrudes into the axially-extending aperture of the cam when the cylinder lock is in the internal-clutch-engaged configuration or position such that the external clutch is caused to become rotationally decoupled from the cam. Optionally, the drive member comprises an axially-extending projection which is configured to protrude into the axially-extending aperture of the cam such that the external clutch is caused to become rotationally decoupled from the cam.

Optionally, the cylinder lock is configured such that the external clutch is caused to become rotationally decoupled from the cam by the axially-extending projection of the internal clutch acting on, e.g. pushing against, the external clutch thereby moving the external clutch out of engagement with the cam when a key is inserted into a key slot of the internal barrel.

Optionally, the key pushes against the internal clutch.

Optionally, the cylinder lock is configured such that, when the axially extending projection of the internal clutch, or optionally of the drive member, protrudes into the axially-extending aperture of the cam, the external clutch is caused to move out of engagement with the cam against the biasing force biasing the external clutch into the external-clutch-engaged configuration or position.

Optionally, the external clutch comprises an axially extending sprung-finger which, when the cylinder lock is in the external-clutch-engaged configuration or position, protrudes into 30 the axially-extending aperture of the cam such that the internal clutch is caused to become rotationally decoupled from the cam.

Optionally, the internal clutch is caused to become rotationally decoupled from the cam by the sprung-finger of the external clutch acting on, e.g. pushing against, the internal clutch 35 thereby moving the internal clutch out of locking engagement with the cam.

Optionally, the cylinder lock is configured such that, when the axially extending projection of the internal clutch protrudes into the axially-extending aperture of the cam, the external clutch is caused to move out of locking engagement with the cam against the biasing force biasing the external clutch into the external-clutch-engaged configuration or position.

Optionally, the cylinder lock is configured such that, when a key is inserted into a key slot of the external barrel, the sprung-finger of the external clutch acts on, e.g. pushes against, the internal clutch thereby moving the internal clutch out of engagement with the cam and thereby causing the internal clutch to become rotationally decoupled from the cam.

Optionally, the key pushes against the external clutch, e.g. the external clutch base.

Optionally, the cylinder lock comprises a security configuration in which the internal clutch is non-disengagably engaged with the cam so as to prevent rotation of the cam, the cylinder lock further comprising a security mechanism configured to maintain the cylinder lock in the 15 security configuration upon removal of a sacrificial portion of the external side of the body.

Optionally, the internal clutch comprises a stop and wherein the security mechanism comprises a blocking member arranged in, and biased to protrude from, an aperture provided in the internal side of the body, such that the internal clutch is restrained from axial movement when the blocking member protrudes from the aperture and engages the stop of the internal clutch.

Optionally, the external side of the body comprises a pre-weakened portion of the body to define the sacrificial portion.

Optionally, the internal lock actuator comprises a thumb-turn mechanism configured to actuate the internal lock actuator from the internal side of the door. Optionally the thumb-turn mechanism is operably couplable to the cam for actuating the cam.

Optionally, the thumb-turn mechanism comprises a shaft rotatable by a user, the shaft being slidably received by, and rotatable within, the internal side of the body, the drive member (or optionally the internal clutch) being slidably received by, and rotatably received within, the internal side of the body, the shaft comprising biasing means configured to bias the drive member axially towards the cam. Herein, the term "axially", unless otherwise specified, is intended to mean parallel to a longitudinal axis of the cylinder lock body i.e. parallel to the rotational axis of the cam. Optionally, the internal clutch is arranged within an axially-extending bore in the internal side of the body. Optionally the biasing means is additionally or alternatively configured to bias the internal clutch axially away from the internal side of the cylinder body, or from the internal barrel. The internal clutch may also be referred to as a thimble and vice versa. Optionally the shaft comprises locking formations for rotationally locking the shaft to the internal clutch (i.e. thimble) upon engagement of the shaft with the internal clutch by the shaft and the internal clutch moving axially together.

Optionally, the shaft comprises an axially extending projection which is configured to be slidably received by the drive member (or optionally the internal clutch).

Optionally, the drive member (or optionally the internal clutch) comprises at least one radially extending aperture or recess configured to receive a first blocking member arranged in, and biased to protrude from, a first aperture provided in the internal side of the body, such that the drive member (or optionally the internal clutch) is rotationally locked to the internal side of the body when the first blocking member is received by one of the at least one radially extending apertures.

Optionally, the drive member (or optionally the internal clutch) comprises a plurality of radially extending and angularly-equispaced apertures, each being configured to receive a blocking member arranged in, and biased to protrude from, a first aperture provided in the 20 internal side of the body.

Optionally, the drive member (or optionally the internal clutch) comprises a stop and the internal side of the body comprises a second blocking member arranged in, and biased to protrude from, a second aperture provided in the internal side of the body, the second blocking member being configured to engage the stop of the drive member (or optionally the internal clutch) so as to prevent axial movement of the drive member (or optionally the internal clutch) in at least one axial direction, optionally in the direction away from the cam, optionally in both axial directions, when the second blocking member is in engagement with the stop. For example, the second blocking member may optionally be configured to engage the stop of the internal clutch so as to prevent movement of the internal clutch away from the coupling element or cam such that the internal clutch remains rotationally coupled with the coupling element.

Optionally, the internal clutch is selectively rotationally couplable to an coupling element, 35 the coupling element being rotationally coupled to the cam such that rotation of the internal clutch causes rotation of the cam when the internal clutch is rotationally coupled to the coupling element. Optionally, the coupling element is arranged within an axially-extending bore within the internal side of the body. The coupling element may optionally be referred to as an internal clutch coupling element or internal clutch coupling.

Optionally, the coupling element is non-disengageably rotationally coupled to the cam.

Optionally, axial movement of the internal clutch towards the coupling element causes the internal clutch to rotationally couple with the coupling element, and wherein axial movement of the internal clutch away from the coupling element causes the internal clutch to rotationally decouple from the coupling element. Optionally, the internal clutch and coupling element comprise corresponding locking formations and wherein axial movement of the internal clutch towards the coupling element causes the locking formations to engage so as to rotationally couple the internal clutch with the coupling element, and wherein axial movement of the internal clutch away from the coupling element causes the locking formations to disengage so as to rotationally decouple the internal clutch from the coupling element.

Optionally, the cylinder lock further comprises a biasing means configured to bias the internal clutch into engagement with the coupling element. Optionally the biasing means comprises a finger biased away from the shaft and biased into engagement with the thimble.

Optionally, the finger is slidingly received within and biased to protrude from an axially extending aperture provided in the shaft.

Optionally, the rotational coupling of the internal clutch and the coupling element is provided by corresponding locking formations provided on the internal clutch and the coupling element. Optionally, the coupling element comprises an axially extending bore comprising axially extending locking formations configured to receive corresponding locking formations provided on an axially extending projection of the internal clutch. Optionally, the axially extending projection of the internal clutch comprises circumferentially arrange equiangularly spaced flat surfaces configured to engage corresponding flat surfaces provided in the axially extending bore of the coupling element.

Optionally, the coupling element is rotationally coupled to the cam by corresponding locking formations provided on the coupling element and the cam.

Optionally, the cylinder lock is configured such that removal of a sacrificial portion of the external side of the body causes the drive member (or optionally the internal clutch) to nondisengagably rotationally couple with the cam (or optionally with the drive member coupling or the coupling element) and the internal clutch to become rotationally coupled to the internal side of the body such that the cam becomes rotationally locked with respect to the body.

Optionally, the cylinder lock is configured such that removal of a sacrificial portion of the external side of the body causes the drive member (or optionally the internal clutch) to nondisengagably rotationally couple with the coupling element, the drive member (or optionally the internal clutch) being rotationally coupled to the body, such that the cam becomes rotationally locked with respect to the body.

Optionally, the drive member is biased indirectly against the sacrificial portion such that removal of the sacrificial portion causes the drive member to non-disengagably rotationally couple with the cam, thereby rotationally locking the cam to the internal side of the body of the cylinder lock.

Optionally, the internal clutch is biased indirectly against the sacrificial portion such that removal of the sacrificial portion causes the internal clutch to non-disengagably rotationally couple with the coupling element, thereby rotationally locking the cam to the internal side of the body of the cylinder lock.

Optionally, the cam is configured to rotate, for actuating a locking mechanism of the door, 25 about a cam axis between a first rotational position thereof corresponding to a locked configuration of the door and a second rotational position thereof corresponding to an unlocked configuration of the door.

Optionally, the cam comprises a radially extending lug for actuating a locking mechanism 30 of the door upon rotation of the cam.

Optionally, the chamfered edge has a chamfer angle of between about 1 degrees and 89 degrees relative to a longitudinal axis of the cylinder lock, optionally about, or a range defined by any combination of, 1, 10, 20, 30, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85 degrees or any intermediate value between 1 and 89 degrees or combination thereof relative to a longitudinal axis of the cylinder lock. Optionally the chamfer angel is between 0 and 90 degrees relative to a longitudinal axis of the cylinder lock.

Optionally, the cam is affixed to the internal side of the body by an attachment means so as to inhibit removal of the cam from the cylinder lock or the internal side of the body, e.g. during an intrusion attack from the external side of the door. Optionally, the attachment 5 means does not rotationally couple the cam to the internal barrel.

Optionally, the cam is prevented from axial movement, in at least one axial direction, relative to the internal side of the body by the attachment means, optionally wherein the cam is prevented from moving axially away from the internal side of the body by the attachment 10 means.

Optionally, the attachment means is configured to affix the cam to a coupling element provided within the internal side of the body, the coupling element being axially restrained with respect to (e.g. axially locked to) the internal side of the body and therefore prevented from moving axially, in at least one axial direction, relative to the internal side of the body, optionally the coupling element is prevented from being removed from the internal side of the body. Optionally, the thimble coupling comprises a circumferential groove provided on an outer surface thereof, wherein the circumferential groove is configured to receive a pin in sliding engagement therein such that the pin is configured to slide within the circumferential groove upon rotation of the thimble coupling about the rotational axis of the cam. Optionally the pin is biased from an aperture provided in the internal side of the cylinder body into engagement with the circumferential groove of the thimble coupling.

Optionally, the cam is affixed to the internal barrel, e.g. to an end portion of the internal barrel, by the attachment means and the internal barrel is affixed to the internal side of the body, such that the cam is indirectly affixed to the internal side of the body by the attachment means via the internal barrel. Optionally the end portion is an end portion of the internal barrel closest to the external side of the barrel, e.g. the end of the internal barrel adjacent to the cam.

Optionally, the cam is prevented from axial movement relative to the internal barrel by the attachment means, and optionally wherein the attachment means does not rotationally couple the cam to the internal barrel.

Optionally, the cam comprises a recess or circumferential groove for receiving the attachment means.

Optionally, the cam is configured so as to cover at least a portion of the recess or circumferential groove and/or attachment means when attached to the internal barrel such that external access to the attachment means in at least one rotational position of the cam is prevented.

Optionally, the recess or circumferential groove is arranged on an inner surface of the cam, e.g. optionally the recess or circumferential groove is provided in an inner annular circumferential surface of the cam, so as to be externally inaccessible.

Optionally, the internal barrel comprises a recess or circumferential groove for receiving the attachment means for affixing the cam to the internal barrel.

Optionally, the recess or circumferential groove of the internal barrel is arranged on an outer surface of the internal barrel.

Optionally, the coupling element comprises a recess or circumferential groove for receiving the attachment means for affixing the cam to the internal side of the body.

Optionally, the recess or circumferential groove of the coupling element is arranged on an 20 outer surface of the coupling element, e.g. an outer circumferential surface of the coupling element.

Optionally, the cam comprises an access window for providing access to the attachment means for removing or installing the attachment means.

Optionally, the attachment means is a snap ring.

Optionally, the snap ring is provided within a circumferential groove provided in an inner surface of the cam and a corresponding circumferential groove provided in an outer surface of the internal barrel, e.g. an outer circumferential surface of the internal barrel.

Optionally, the snap ring is provided within a circumferential groove provided in an inner surface of the cam and a corresponding circumferential groove provided in an outer surface of the coupling element.

According to a second aspect of the present invention, there is provided cam for a cylinder lock having an externally-accessible side and an internally accessible side opposite the externally-accessible side, the externally-accessible side being accessible from the external side of a door when the cylinder lock is installed in a door and the internally-accessible side being accessible from the internal side of a door when the cylinder lock is installed in a door, the cam comprising: a peripherally extending rounded or chamfered edge on an outer circumferential surface of the cam; wherein the cam is configured such that, when installed in the cylinder lock, the rounded or chamfered edge faces towards the externally-accessible side of the cylinder lock. Optionally, the rounded or chamfered edge is provided on an outer circumferential surface of the cam. Optionally the cam comprises a radially extending lug for actuating a locking mechanism of the door upon rotation of the cam. Optionally, the cam comprises a recess or circumferential groove on an inner surface of the cam, e.g. an inner annular circumferential surface of the cam, for receiving an attachment means (e.g. a snap ring) for attaching the cam to an internal barrel of the cylinder lock. Optionally the cylinder lock may be a Euro Cylinder Lock.

Optionally, the cam comprises an external end at a first end of the cam and an internal end at a second end of the cam, opposed to the first end, the external end and internal end corresponding to the externally-accessible side and the internally-accessible side of the cylinder lock respectively, and wherein the peripherally extending chamfered or rounded edge is provided at or towards the external end of the cam. Optionally, the rounded or chamfered edge is arranged so as to face towards the external surface or side of the door when the cylinder lock is installed in the door. Optionally the external and internal ends of the cam are axial ends of the cam, for example arranged at opposite ends of the rotational axis of the cam or the longitudinal axis of the cam. Optionally the peripherally extending chamfered or rounded edge is provided at or towards the external end of the cam so as to prevent the cam from being gripped during an intrusion attack, for example by a pair of pliers or a clamping device.

Optionally, the chamfered edge has a chamfer angle of between about 1 degrees and 89 degrees relative to a longitudinal axis of the cylinder lock or cam or the rotational axis of the cam, optionally about, or a range defined by any combination of, 1, 10, 20, 30, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85 degrees or any intermediate value between 1 and 89 degrees or combination thereof relative to a longitudinal axis of the cylinder lock. Optionally the chamfer angel is between 0 and 90 degrees relative to a longitudinal axis of the cylinder lock.

Optionally, the chamfered or rounded edge protrudes axially from the external end of the cam.

According to a third aspect of the present invention, there is provided a cylinder lock for a door having an internal side and an external side, the cylinder lock comprising: a body having an internal side configured to be arranged on the internal side of the door when the cylinder lock is installed in the door; and the body also having an external 5 side configured to be arranged on the external side of the door when the cylinder lock is installed in the door; a cam for actuating a locking means of the door, the cam being arranged between the internal side of the body and the external side of the body; and wherein the cam is affixed to the internal side of the body by an attachment means so as to 10 inhibit removal of the cam from the cylinder lock or internal side of the body, e.g. during an intrusion attack from the external side of the door. Optionally the cylinder lock may be a Euro Cylinder Lock.

Optionally, the cam is configured to rotate, for actuating a locking mechanism of the door, 15 about a cam axis between a first rotational position corresponding to an unlocked configuration of the door and second rotational position corresponding to a locked configuration of the door.

Optionally, the cam is prevented from axial movement, in at least one axial direction, relative 20 to the internal side of the body by the attachment means, optionally wherein the cam is prevented from moving axially away from the internal side of the body by the attachment means.

Optionally, the attachment means is configured to affix the cam to a coupling element provided within the internal side of the body, the coupling element being axially restrained with respect to (e.g. axially locked to or fixed with respect to) the internal side of the body and thereby prevented from moving axially, in at least one axial direction, relative to the internal side of the body, optionally the coupling element is prevented from moving axially away from the internal side of the body.

Optionally, the coupling element is provided within a longitudinally extending through-bore provided in the internal side of the body.

Optionally, the cam is affixed to a barrel rotatably received within a longitudinally extending 35 through-bore provided in the internal side of the cylinder body, e.g. to an end portion of the internal barrel, by the attachment means and optionally the barrel is affixed to the internal side of the body such that the cam is indirectly affixed to the internal side of the body by the attachment means via the barrel.

Optionally, the cam is prevented from axial movement relative to the barrel by the 5 attachment means, and optionally wherein the attachment means does not rotationally couple the cam to the internal barrel.

Optionally, the cam covers at least a portion of, or optionally the entirety of, the recess or circumferential groove and/or attachment means when the cam is attached to the internal barrel such that external access to the attachment means in at least one rotational position of, optionally in all rotational positions of, the cam is prevented Optionally, the recess or circumferential groove is arranged on an inner surface of the cam, e.g. optionally the recess or circumferential groove is provided in an inner annular circumferential surface of the cam, so as to inhibit external access to at least a portion of the circumferential groove.

Optionally, the barrel comprises a recess or circumferential groove for receiving the attachment means for affixing the cam to the barrel.

Optionally, the recess or circumferential groove of the barrel is arranged on an outer 25 circumferential surface of the barrel Optionally, the coupling element comprises a recess or circumferential groove for receiving the attachment means for affixing the cam to the internal side of the body.

Optionally, the recess or circumferential groove of the coupling element is arranged on an outer circumferential surface of the coupling element.

Optionally, the cam comprises an access window or for providing access to the attachment means for removing or installing the attachment means.

Optionally, the attachment means is a snap ring.

According to a fourth aspect of the present invention, there is provided a method of manufacturing the cylinder lock of the first aspect of the present invention.

According to a fifth aspect of the present invention, there is provided a method of 5 manufacturing the cam of the second aspect of the present invention.

According to a sixth aspect of the present invention, there is provided a method of manufacturing the cylinder lock of the third aspect of the present invention.

The present invention may be carried out in various ways and preferred embodiments of a cylinder lock in accordance with the invention will now be described by way of example with reference to the accompanying drawings, in which: Fig. 1 is an isometric exploded view of a double barrel cylinder lock according to a first 15 embodiment of the present invention.

Fig. 2A is a side-on cutaway view of the cylinder lock of Fig. 1, showing the internal side of the lock on the left hand side of the figure and the external side of the lock on the right hand side of the figure, in which the cylinder lock is shown in a rest configuration, that is when it is not being operated and so without a key having been inserted in either end of the cylinder lock and with the cylinder lock body intact, prior to a snapping intrusion attack.

Fig. 2B is a detail view of a portion of Fig. 2A, showing the configuration of the cam, internal clutch and external clutch, among other features, in particular detail.

Fig. 2C is a side-on cutaway view of the cylinder lock of Fig. 1 and is similar to Fig. 2A but shows the configuration of the cylinder lock when a key has been inserted into the internal side of the cylinder lock. This configuration may be referred to as the internal-clutchengaged configuration or position as the internal clutch is rotationally engaged with the cam, but the external clutch is held out of rotational engagement with the cam.

Fig. 2D is a detail view of a portion of Fig. 2C, showing the configuration of the cam, internal clutch and external clutch, among other features, in particular detail.

Fig. 2E is a side-on cutaway view of the cylinder lock of Fig. 1 and is similar to Figs. 2A and C but shows the configuration of the cylinder lock when a key has been inserted into the external side of the cylinder lock. This configuration may be referred to as the external-clutch-engaged configuration as the external clutch is rotationally engaged with the cam, but the internal clutch is held out of rotational engagement with the cam.

Fig. 2F is a detail view of a portion of Fig. 2E, showing the configuration of the cam, internal 5 clutch and external clutch, among other features, in particular detail.

Fig. 2G is a side-on cutaway view of the cylinder lock of Fig. 1 and is similar to Figs. 2A, C and E but shows the configuration of the cylinder lock after a sacrificial portion of the cylinder body has been removed during a snapping intrusion attack.

Fig. 2H is a detail view of a portion of Fig. 2G, showing the configuration of the cam and internal clutch, among other features, in particular detail.

Fig. 21 is a side-on cutaway view of the cylinder lock of Fig. 1 and is similar to Figs. 2A, C, E and G but shows the configuration of the cylinder lock after a sacrificial portion of cylinder body has been removed during a snapping intrusion attack and after a key has been inserted in the internal barrel so as to enable the cam to be actuated in order to unlock the door.

Fig. 2J is a detail view of a portion of Fig. 21, showing the configuration of the cam and internal clutch, among other features, in particular detail.

Fig. 3 is an isometric exploded view of a thumb-turn barrel cylinder lock according to a second embodiment of the present invention.

Fig. 4A is a side-on cutaway view of the cylinder lock of Fig. 3, showing the internal side of the lock on the left hand side of the figure and the external side of the lock on the right hand side of the figure, in which the cylinder lock is shown in a resting state, that is without a key having been inserted in the external barrel, without the thumbturn being depressed, and with the cylinder lock body intact, prior to a snapping intrusion attack.

Fig. 4B is a detail view of a portion of Fig. 4A, showing the configuration of the cam, internal clutch, coupling element and external clutch, among other features, in particular detail.

Fig. 4C is a side-on cutaway view of the cylinder lock of Fig. 3 and is similar to Fig. 4A but shows the configuration of the cylinder lock when the thumbturn is depressed. This configuration may be referred to as the internal-clutch-engaged configuration as the internal clutch is rotationally engaged with the cam, but the external clutch is held out of rotational engagement with the cam. This configuration or position may also be referred to as the thumbturn-coupled configuration or position as the thumbturn is rotationally coupled to the cam.

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Fig. 4D is a detail view of a portion of Fig. 4C, showing the configuration of the cam, internal clutch, coupling element, and external clutch, among other features, in particular detail.

Fig. 4E is a side-on cutaway view of the cylinder lock of Fig. 3 and is similar to Figs. 4A and C but shows the configuration of the cylinder lock when a key has been inserted into the external side of the cylinder lock. This configuration may be referred to as the externalclutch-engaged configuration as the external clutch is rotationally engaged with the cam, but the internal clutch is held out of rotational engagement with the cam.

Fig. 4F is a detail view of a portion of Fig. 4E, showing the configuration of the cam, internal clutch, coupling element, and external clutch, among other features, in particular detail.

Fig. 4G is a side-on cutaway view of the cylinder lock of Fig. 3 and is similar to Figs. 4A, C and E but shows the configuration of the cylinder lock after a sacrificial portion of the cylinder 20 body has been removed during a snapping intrusion attack.

Fig. 4H is a detail view of a portion of Fig. 4G, showing the configuration of the cam, internal clutch, coupling element, and external clutch, among other features, in particular detail.

Fig. 41 is a side-on cutaway view of the cylinder lock of Fig. 3 and is similar to Figs. 4A, C, E and G but shows the configuration of the cylinder lock after a sacrificial portion of cylinder body has been removed during a snapping intrusion attack and after the thumbturn has been depressed so as to rotationally couple the thumbturn with the cam and thereby enable the cam to be actuated by rotation of the thumbturn in order to unlock the door.

Fig. 4J is a detail view of a portion of Fig. 41, showing the configuration of the cam, internal clutch and the coupling element, among other features, in particular detail.

Fig. 5 is an isometric exploded view of a thumb-turn barrel cylinder lock according to a third 35 embodiment of the present invention.

Fig. 6A is a side-on cutaway view of the cylinder lock of Fig. 5, showing the internal side of the lock on the left hand side of the figure and the external side of the lock on the right hand side of the figure, in which the cylinder lock is shown in a resting state, that is without a key having been inserted in the external barrel, without the thumbturn being depressed, and with the cylinder lock body intact, prior to a snapping intrusion attack.

Fig. 6B is a detail view of a portion of Fig. 6A, showing the configuration of the cam, internal clutch, coupling element and external clutch, among other features, in particular detail.

Fig. 6C is a side-on cutaway view of the cylinder lock of Fig. 5 and is similar to Fig. 6A but shows the configuration of the cylinder lock when the thumbturn is depressed. This configuration may be referred to as the thumbturn-coupled configuration or position as the thumbturn is rotationally coupled with the cam, but the external clutch is held out of rotational engagement with the cam.

Fig. 6D is a detail view of a portion of Fig. 6C, showing the configuration of the cam, drive member, drive member coupling, and external clutch, among other features, in particular detail.

Fig. 6E is a side-on cutaway view of the cylinder lock of Fig. Sand is similar to Figs. 6A and C but shows the configuration of the cylinder lock when a key has been inserted into the external side of the cylinder lock. This configuration may be referred to as the externalclutch-engaged configuration as the external clutch is rotationally engaged with the cam, but the thumbturn is rotationally decoupled with the cam.

Fig. 6F is a detail view of a portion of Fig. 6E, showing the configuration of the cam, drive member, drive member coupling, and external clutch, among other features, in particular detail.

Fig. 6G is a side-on cutaway view of the cylinder lock of Fig. 5 and is similar to Figs. 6A, C and E but shows the configuration of the cylinder lock after a sacrificial portion of the cylinder body has been removed during a snapping intrusion attack.

Fig. 6H is a detail view of a portion of Fig. 6G, showing the configuration of the cam, drive 35 member, drive member coupling, and external clutch, among other features, in particular detail.

Fig. 61 is a side-on cutaway view of the cylinder lock of Fig. 5 and is similar to Figs. 6A, C, E and G but shows the configuration of the cylinder lock after a sacrificial portion of cylinder body has been removed during a snapping intrusion attack and after the thumbturn has been depressed so as to rotationally couple the thumbturn with the cam and thereby enable the cam to be actuated by rotation of the thumbtum in order to unlock the door.

Fig. 6J is a detail view of a portion of Fig. 61, showing the configuration of the cam, internal clutch and the coupling element, among other features, in particular detail.

A cylinder lock 1 according to a first embodiment of the present invention is shown in Fig. 1. The cylinder lock 1 is configured to be installed in a door (not shown) for preventing access to a room, building or space (not shown) on one side (the internal or interior side or face or surface of the door, opposite to the external side or face or surface of the door). The internal side/face/surface of the door is the side/face/surface of the door to which to cylinder lock 1 is configured to selectively provide or prevent access. Unauthorised access attacks therefore occur from the external side of the door in an attempt to gain access to the room, building or space on the interior side of the door. The embodiment of Fig. 1 is a Double Barrel cylinder lock as it comprises an internal locking barrel 15 as well as an external locking barrel 13: thus a locking barrel is provided on each of the internal Sand external 6 sides of the cylinder lock body 4.

The cylinder lock 1 comprises a body 4 which comprises an internal side 5 and an external side 6. The cylinder lock 1 is configured to be installed in a door such that the internal side 5 and external side 6 of the cylinder lock 1 correspond to, i.e. are on or towards the same 25 side of the door as, the internal and external sides of the door respectively.

A bridge portion 3 of the body 4 adjoins the internal 5 and external sides 6 of the body 4. A cam 7 is arranged between the internal Sand external 6 sides of the body 4. The cam 7 is arranged for rotation about the longitudinal axis (i.e. an axis extending from the internal side 5 to the external side 6) of the body 4 between a first rotational position corresponding to a locked configuration of the door and a second rotational position corresponding to an unlocked configuration of the door. A lug 51 provided on the cam is configured for selectively actuating a locking mechanism (not shown) of the door when the cylinder lock 1 is installed in the door upon rotation of the cam 7 about the rotational axis of the cam 7 from the second "unlocked" rotational position of the cam 7 to the second "locked" rotational position of the cam 7. The rotational axis of the cam 7 may also be referred to as the cam rotation axis or the cam axis.

The cam 7 itself comprises an internal side 36 and an external side 37 corresponding to the internal and external sides of the cylinder lock body 4 respectively such that, when the cylinder lock 1 is installed in a door, the internal side 36 of the cam 7 is arranged closest to, or on or towards the side of, the internal (or interior) side of the door and vice versa with respect to the external side 37 of the cam 7. At the extremities of the cam 7 along the cam axis are the cam internal end 11 and the cam external end 12 which are opposed and are spaced apart from each other.

A chamfered, or in some embodiments a rounded, peripherally-extending or circumferentially-extending edge or surface 8 is provided on an outer circumferential surface of the cam 7. The chamfered or rounded edge 8 may also be referred to as a gradiated edge or surface in that the edge or surface may have a gradient of more than zero but less than 90 degrees (for example 20, 30, 40, 45, 50, 55, 60, or 70 degrees), or could be continuously or smoothly varied between at least two different gradients, relative to the cam axis -indeed a chamfered edge 8 or rounded edge 8 are examples of a gradiated edge and each comprise a gradiated surface (albeit, for rounded edges, the gradient of the gradiated surface increases continuously in one axial direction). This chamfered edge or rounded edge 8 faces towards the external side of the lock, i.e. the direction normal to a plane of the chamfer edge or surface 8 (or rounded edge or surface, where a rounded edge 8 is provided) has a component which extends away from the cam 7 towards the external side 6 of the cylinder lock body 4. The chamfered or rounded edge 8 is configured such that the edge 8 resists a pair of pliers or other such grasping or clamping tool being secured to the cam 7 as the nose of the pliers are caused to slide off of the cam 7 when the nose of the pliers or tool engage the angled surface of the chamfered or rounded edge 8. Thus, the chamfered or rounded edge 8 provides a particularly effective means of preventing the cam 7 from being removed from the cylinder lock 1 during a snapping intrusion attack from the external side 6 of the cylinder lock body 4 in which a sacrificial portion 31 of the external side 6 of the cylinder lock body 4 has been snapped off. Preventing removal of the cam 7 is an effective way of preventing access to the locking mechanism provided within the door itself which is normally actuated by rotation of the cam 7 and upon engagement with the lug 51 of the cam 7, as typically, during an snapping intrusion attack, the cam 7 is removed for providing access to the locking mechanism of the door.

The chamfered or rounded edge 8 may be provided at any location along the cam 7, for example it may be provided on the internal side 36 or the external side 37 of the cam 7 so long as the chamfered or rounded edge 8 prevents a clamping tool from being secured to the cam during an external attack. Particularly advantageously however, the chamfered or rounded edge 8 may be provided at the external end 12 of the cam 7 as this prevents a clamping tool from being applied to the external end 12 of the cam 7 which is the end most readily accessible from the external side of the door and the end to which a greatest snapping bending moment may be applied during an attack, and that which an attacker is most likely to attempt to grasp by a grasping or clamping tool such as a pair of pliers.

The chamfered or rounded edge 8 may have many forms provided that it has an angled peripherally or circumferentially extending surface which is angled towards the external side 6 of the cylinder lock body 4. By angled towards, it is meant that the direction normal to the plane of the angled surface has a component which extends away from the angled surface and towards the external side 6 of the cylinder lock body 4. The angle (relative to the cam axis) of this angled surface may vary continuously or smoothly along the cam axis (as a rounded edge does) or may have a constant angle, as a chamfered edge does.

When the edge 8 is a rounded edge, it may have a round radius of 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5 or 10mm or any intermediate value therebetween or may be a range between any of these values.

When the edge 8 is a chamfered edge, it may have a chamfer angle of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 25, or 30 degrees as measured from the cam rotation axis, or any intermediate value therebetween or may be a range between any of these values.

While the edge 8 in this embodiment extends around the entire outer perimeter or circumference of the cam 7 it may in other embodiments extend only partially around the outer perimeter or circumference, for example only 45, 60, 90, 120, 180, 240, 270, 320 degrees or some fraction or extent of the full perimeter or circumference of the cam 7, and so may form a peripherally-extending or circumferential arc about the cam axis.

Referring to the cylinder lock 1 more generally now, the internal side 5 of the body 4 and the external side 6 of the body 4 each comprise a lock actuator 9, 10 configured to be actuatable from the internal and external side respectively of the door when the cylinder lock 1 is installed in the door. While the internal 9 and external lock actuators 10 may take many different forms, in the example shown they comprise an internal barrel 15 and an external barrel 13 each rotatably received within the internal side 5 and external side 6 respectively of the cylinder lock body 4 within a longitudinally extending throughbore 63, 64 provided in each of the internal side Sand external side 6 of the body 4. Each of the internal 63 and external 64 throughbores are arranged such that their longitudinal axis is aligned with the cam rotation axis. The internal barrel 15 is located with respect to the internal side 5 of the body 4 by way of circlip 88 (Fig. 2) which sits in a circumferential groove 89 provided in the external end of the internal barrel 15 and engages an externally-facing face of the internal side 5 of the body 4, adjacent to the cam 7. Similarly, the external barrel 13 is located with respect to the external side 6 of the body 4 by way of circlip 59 which is arranged in a circumferential groove 104 provided in the internal end of the external barrel 13 and engages an internally-facing face of the external side 6 of the body 4, adjacent to the cam 7.

Each of the internal barrel 15 and external barrel 13 comprise a set of sprung differ pins and tumblers 78, 79 and a keyslot 14, 16 for receiving a key and aligning the differ pins 78, 79 upon insertion of the key in the keyslot 14, 16 along a shear plane of their respective barrels 13, 15 for permitting rotation of the barrels 13, 15 within their respective throughbores 63, 64 about the longitudinal axis of the body 4 in the usual fashion and so will not be described in greater detail herein. Thus the internal 16 and external 14 keyslots are configured to actuate the internal 9 and external 10 lock actuators respectively. The external barrel 13 also comprises anti-drill pins 72 and 73 having a longitudinal axis aligned parallel (preferably co-axial, i.e. radially arranged) to the diameter of the barrel 13 and spaced apart so as to be provided on opposing sides of the external keyslot 14 and generally towards the external end of the external barrel 13. A further anti-drill pin 68 is provided in a radially extending aperture 82 in the external side 6 of the body 4, adjacent to the cam 7 and bridge portion 3.

The internal 15 and external 13 barrels are selectively rotationally couplable and decouplable with or to the cam 7 such that rotation of the internal barrel 15, when rotationally coupled to the cam 7, causes rotation of the cam 7 about the cam axis and, similarly, such that rotation of the external barrel 13, when rotationally coupled to the cam 7, causes rotation of the cam 7 about the cam axis.

So that rotation of the internal barrel 15 may rotate the cam 7 when it is rotationally coupled to the cam 7, the external barrel 13 may be rotationally decoupled from the cam 7 when the internal barrel 15 is rotationally coupled to the cam 7. Similarly, so that rotation of the external barrel 13 may rotate the cam 7 when it is rotationally coupled to the cam 7, the internal barrel 15 may be rotationally decoupled from the cam 7 when the external barrel 15 is rotationally coupled to the cam 7.

An internal clutch 35, arranged within and configured to slide along the throughbore 63 of the internal side 5 of the body 4, provides the selective coupling and decoupling of the internal barrel 15 to the cam 7. The internal clutch 35 is configured to selectively form a rotational drive path between the internal barrel 15 and the cam 7 such that rotation of the internal barrel 15 causes rotation of the cam 7 when the rotational drive path is formed or established. The internal clutch 35 is biased into engagement, i.e. into rotational coupling, with the cam 7 by internal clutch spring 41 which forms an internal clutch biasing means 40 such that a locking formation 38, in this example an axially projecting projection or tab 38, engages a corresponding locking formation 39 provided on the internal side of the cam 7.

In this example, the cam locking formation 39 is in the form of a rectangular slot 39 configured to receive, and corresponding to, the tab 38 of the internal clutch 35, although other such suitable locking formations may instead be used. The rectangular slot 39 itself forms part of an axially extending aperture 48 which extends through the cam 7 (although this is not essential, but facilitates manufacture of the cam 7). Thus, engagement of these locking formations 38, 39 causes the internal clutch 35 to become rotationally coupled to the cam 7. The internal clutch spring 40 sits within a spring cup 60 to prevent the spring 40 from buckling when compressed and to maintain its alignment along throughbore 63. The spring cup 60 itself abuts against a barrel spacer 61 which may or may not be provided, depending on the length of the internal side 5 of the body 4. Some embodiments of the invention may not include a spring cup 60 and so spring cup 60 and barrel spacer 61 are not essential. The barrel spacer 61 abuts against the end of the internal keyslot 16.

The internal clutch 35 is slidlingly received within the internal barrel 15 by way of a radially-projecting key 80 provided on the internal clutch 35 which rides along axially extending 25 keyway 81 provided in the internal barrel 15.

The cam 7 is affixed to or secured to the external end 53 of the internal barrel 15 by an attachment means 52 which in this embodiment takes the form of a snap ring 58 which sits in a circumferential groove 54 (Fig. 2F) provided in an inner annular surface 55 of the cam 7 and in a corresponding outer circumferential groove 2 provided at the external end 53 of the internal barrel 15. Thus, the attachment means 52 is not easily accessible from the external side 6 of the body 4 for removal during an attack as the cam 7 covers, at least a portion of, the attachment means, although in this example the cam 7 comprises a partially circumferentially extending access window 57 at the internal end 11 of the cam 7 for providing access to the attachment means 52 for removing or installing the attachment means 52, at least in certain rotational positions of the cam 7. Thus cam 7 is securely attached to internal side 5 of the body 4 via the internal barrel 15 so as to hinder its removal during an external attack. The cam 7 is thus axially retained to the internal barrel 15 by the attachment means 52 while not restricting or restraining rotational movement of the cam 7 with respect to the body 4.

By preventing the cam 7 from being removed during an attack in this way, a particularly secure cylinder lock 1 is provided as the inner locking mechanism of the door is even more difficult to access by an attacker. Thus, the rounded or chamfered edge 8 works in a synergistic way with the attachment means 52 for providing yet an even more secure cylinder lock 1 as, not only does the attachment means 52 make it difficult to remove the cam 7 as it is secured by the attachment means 52 to the internal side 5 of the body 4, but removal of the cam 7 is made yet even more difficult by the chamfered or rounded edge 8 as this prevents an attacker from securely grasping the cam 7 by preventing, or at least hindering, secure attachment of a clamping tool such as a pair of pliers to the cam 7.

The internal side 5 of the body 4 also comprises a security mechanism which comprises a blocking member 23 (here in the form of a disc or pin 23, although any other suitable form may instead be used) which sits upon a ball bearing 65 to provide a shear plane therebetween and a spring 66 which sits on a plug 67 to close the end of a radially extending aperture 24 provided in the internal side of the body in which the blocking member 23, ball bearing 65 and spring 66 are all arranged. The blocking member 23 is biased to protrude from the radially extending aperture 24 by the spring 66, through an aperture provided in the internal barrel 15, and to engage a stop 50 in the form of a lip or undercut 50 provided in the internal clutch 35 such that the internal clutch 35 is restrained or prevented from moving axially away from the cam 7 when the stop 50 is engaged by the blocking member 23. In this way the internal clutch 35 is held in non-disengageable engagement with the cam 7, thereby non-disengagably rotationally coupling the cam 7 to the internal clutch 35 and thereby to the internal side 5 of the body 4. Thus, in this way, the cam is rotationally locked to the internal side 5 of the body 4 to prevent rotation of the cam 7 with respect to the internal side of the body 4 when the first blocking member 23 engages stop 50.

The external side 6 of the body 4 comprises a sacrificial portion 31, configured to snap and break away during a snapping attack at a predetermined area of weakness 32 defined by a breakaway slot 33 provided in the external side 6 of the body 4. A breakaway slot support 69 is provided in this example, but is not essential, and which sits in the breakaway slot 33 so as to prevent the sacrificial portion 31 becoming bent or damaged prior to installation.

The internal clutch 35 is biased indirectly against the sacrificial portion 31 by the internal clutch biasing means 40 such that removal of the sacrificial portion 31 causes the internal clutch to move axially towards the cam 7 such that the blocking member 23 protrudes from its aperture 24 and engages the stop 50, thereby holding the internal clutch 35 in non-disengageable engagement with the cam.

An external clutch 42, arranged within and configured to slide along the throughbore of the external side 6 of the body 4, provides selective coupling and decoupling of the external barrel 13 to the cam 7. The external clutch 42 is configured to selectively form a rotational drive path between the external barrel 13 and the cam 7 such that rotation of the external barrel 13 causes rotation of the cam 7 when the rotational drive path is formed.

The external clutch 42 comprises a base 46 and a sprung finger 47 biased apart from each other by external clutch spring 45. Although the sprung finger 47 is able to move in an axial direction away from the base 46, the extent to which it can do so is limited. The external clutch 42 is slidlingly received within the external barrel 13 by way of a radially-projecting key 75 provided on the external clutch 42 which rides along axially extending keyway 76 provided in the external barrel 13 so that the external clutch 42 is configured to slide axially away and toward the cam 7. As with the internal clutch 35, the engagement of the key 75 and keyway 75 provides rotational coupling of the external clutch 42 with the external barrel 13.

Locking formations 43 provided on the base 46, in this example in the form of diametrically opposed and radially extending lugs 43 are configured to engage with corresponding locking formations (not shown) provided in the external side 37 of the cam 7 so that the cam 7 and external clutch 42 are rotationally coupled together when the locking formations 43 of the external clutch 42 are engaged with their corresponding locking formations on the cam 7. The external barrel 13 comprises cutouts 77 for receiving and providing clearance for the locking formations 43 in certain configurations of the cylinder lock 1 so that the external clutch 42 is able to move sufficiently away from the cam 7 in the external direction to adopt those configurations.

The sprung-finger 47 comprises an axially extending projection 47. The cam aperture 48 is configured to receive this projection 47 such that the projection 47 is able to protrude or pass sufficiently therethrough so as to be able to directly contact the tab 38 of the internal clutch 35 so as to be able to push the internal clutch 35 out of engagement with the cam 7, and thereby rotationally decouple the intemal clutch 35, and thereby the internal barrel 15, with the cam 7, when a key is inserted into the external keyslot 14. A external barrel spacer 62 may also be provided as an optional feature, depending on the length of the external side 6 of the body 4. The external barrel spacer 62 abuts against the end of the external keyslot 14 and the sprung-finger abuts against the external barrel spacer 62.

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Operation of the cylinder lock of the first embodiment will now be described with reference to Figs 2A to 2J.

Figures 2A and 2B show the cylinder lock in the at rest position in which neither the internal barrel 15 nor the external barrel 13 has a key inserted into their respective keyslots 14, 16 and in which the lock 1 is not in operation by a user and is intact, prior to a snapping intrusion attack. The internal clutch biasing means 40 biases the internal clutch 35 into locking engagement with the cam 7 such that the locking formations 38 on the internal clutch 35 are in engagement with the corresponding locking formations 39, here provided as a slot 39 although other suitable locking formations could instead be used, provided on the internal side 36 of the cam 7. Thus, the cam 7 is rotationally coupled to the internal clutch 35, which is itself rotationally coupled to the internal barrel 15 by way of the engagement of key 80 and keyway 81, and so, as the internal pin and tumbler arrangement 78 is misaligned with its shear plane, the cam 7 is rotationally locked to the internal side 5 of the body 4. The axially extending tab 38 of the internal clutch 35, being biased by the internal clutch biasing means 40, pushes directly on the end of the sprung finger 47, through cam aperture 48, and, causes the external clutch 42 to be held away from the cam 7 such that locking formations 46 of the cam are held out of locking engagement with their corresponding locking formations (not shown) in the cam 7 such that the external clutch 42 is held from locking engagement with the cam 7. Thus the cam 7 is rotationally decoupled from the external clutch 42 and so thereby the cam 7 rotationally decoupled from the external barrel 13. Nevertheless the external barrel 13 is prevented from rotation due to the external pin and tumbler arrangement 79 being misaligned with its shear plane. Thus the cam 7 is rotationally locked to the body 4 in this configuration and is unable to rotate, but only due to the misalignment of the internal pin and tumbler arrangement 78. Although the external clutch base 46 is biased away from the sprung finger 75, they are only able to move a predetermined distance apart from each other and so the external clutch locking formations 43 provided on the base 46 are unable to engage the corresponding locking formations on external side 37 of the cam 7.

The blocking member 23 is depressed within its aperture 24 provided in the internal barrel 15 by the internal clutch 35 riding over it so as to be held out of engagement with the internal clutch stop 50. The internal clutch 35 is prevented from moving sufficiently far to the external side of the body 4 so as to release the blocking member 23 by the sprung finger 47 abutting against the external barrel spacer 62 which itself abuts against the end of the external barrel keyslot 14. In embodiments in which the external barrel spacer 62 is not provided, the sprung finger 47 may instead abut directly against the end of the external barrel keyslot 14.

Turning now to Figures 2C and 2D, these show the configuration of the cylinder lock 1 when a key 95 is inserted into the internal barrel key slot 16. The tip of the key 95 pushes the internal barrel spacer 61, which in turn pushes the spring cup 60 and compresses the internal clutch spring 40. This provides an increased biasing force but the internal clutch 35 is unable to move further in the external direction as it is pushing against the external clutch 42 which is itself indirectly (although in some embodiments in which an external barrel spacer 62 is not provided, directly) resting against the end of the external barrel keyslot 14. The cam 7 is rotationally coupled to the internal barrel 15 via engagement of the respective locking formations of the internal clutch 35 and the cam 7 and is rotationally decoupled from the external clutch 42 and thereby the external barrel 13. The insertion of the key 95 causes the internal pin and tumbler arrangement 78 to align with its shear plane and the internal barrel 15 becomes rotationally decoupled with the internal side of the body 4 such that the key 95 may be rotated to cause rotation of the cam 7, thereby unlocking the door.

Figures 2E and 2F show the configuration of the cylinder lock 1 when a key 95 is inserted into the external barrel key slot 14. The tip of the key 95 pushes against the external barrel spacer 62 (or directly against the sprung finger 47 when an external barrel spacer 62 is not provided) which then pushes against the sprung finger 47. This causes the sprung finger 47 to slide towards the cam 7 in the internal direction, taking the external clutch base 46 with it, via external clutch spring 45. This causes the locking formations on the external clutch base 43 to engage with the corresponding locking formations provided on the external side 37 of the cam 7 and thus the cam 7 becomes rotationally coupled to the external clutch 42.

At the same time, as the external clutch 42 is moved towards the cam 7, a portion of the sprung finger 47 moves further through the cam aperture 48 as to push against the tab 38 of the internal clutch 35, against the biasing force provided by the internal clutch biasing means 40, causing the internal clutch 35 to move away from the cam 7 and thereby to disengage the internal clutch 35 from locking engagement with the cam 7. Thus, the cam 7 is no longer rotationally coupled to the internal barrel 15.

The insertion of the key 95 into the external key slot 14 causes the external pin and tumbler arrangement 79 to align with its shear plane and the external barrel 13 becomes rotationally decoupled from the external side 6 of the body 4 such that the key 95 may now be rotated to cause rotation of the cam 7.

Figures 2G and 2H show the configuration of the cylinder lock 1 when the sacrificial portion 31 has been removed during a snapping intrusion attack from the external side of the lock 1. The sacrificial portion 31 has been snapped at the pre-weakened portion 32 provided by the breakaway slot 33 and has been removed, along with the external clutch 42 and the external barrel spacer 62.

As the sprung finger 47 has in this configuration been removed during the attack, there is nothing stopping the internal clutch biasing means 40 from pushing the internal clutch 35 even further towards the cam 7 (previously, this was prevented by the external clutch abutting, directly or indirectly, against the end of the external barrel keyslot 14) and so the internal clutch 35 slides sufficiently towards the cam 7 that the blocking member 23 is uncovered by the internal clutch and released from its aperture 24 and engages the stop 50 provided in the internal clutch 35. Thus, the engagement of the blocking member 23 with the stop 50 prevents the internal clutch 35 from being pushed out of locking engagement with the cam 7, for example from being pushed from the external side of the lock 1 and so the internal clutch 35 is in non-disengageable engagement with the cam 7 such that the cam 7 is non-disengageably rotationally coupled to the internal barrel 35, which itself is rotationally coupled to the internal barrel 15 by the internal clutch key 80 being slidingly received within the internal barrel keyway 81 and the internal barrel 15 is rotationally coupled to the internal side 5 of the body 4 by the internal pin and tumbler arrangement 78. Thus, the cam 7 is prevented from rotation. Anti-drill pin 68 provided in the body 4 between the aperture 24 and the breakaway slot 33 prevents drilling from the external side to remove the blocking member 23. Furthermore, the cam 7 is unable to be separated from the internal barrel 15 due to the attachment means 52 securely and inaccessibly attaching the cam 7 to the internal barrel 15 and the chamfered or rounded edge 8 of the cam 7 prevents the cam 7 from being gripped or grasped, for example by a clamping tool such as a pair of pliers, by an attacker for removal. Thus the cam 7 prevents access to the locking mechanism of the door which would otherwise be accessible if the cam 7 were able to be removed by the attacker, thereby preventing the door from being opened.

Figures 21 and 2J show the configuration of the cylinder lock 1 when it is desired to unlock the door from the inside/interior after a snapping intrusion attack. A key 95 is inserted into the internal key slot 16, causing the internal pin and tumbler arrangement 78 to align with its shear plane and thereby rotationally decoupling the internal barrel 15 from the internal side 5 of the body 4. When the key 95 is rotated, the internal barrel 15 begins to rotate such that edge of the aperture 24 in the internal barrel 15 through which the blocking member 23 protrudes presses against the ball bearing 65, causing the ball bearing 65 to be pressed back down into its own aperture 66, such that the shear plane between the blocking member 23 and the ball bearing 65 becomes aligned with the shear plane of the internal barrel 15 and the throughbore 63 and also the shear plane of the internal pin and tumbler assembly 78. Thus the internal barrel 15 rotates and, as the internal clutch 35 is rotationally coupled to the cam 7 as the internal clutch locking formations 38 are engaged with their respective locking formations 39 on the internal side of the cam, so with it the cam 7. Thus the cylinder lock 1 is unlocked and the door's locking mechanism may be actuated by the lug 51 of the cam 7 upon rotation of the cam 7 to unlock the door, even after a snapping intrusion attack.

A second embodiment of a cylinder lock according to the present invention is shown in exploded view in Fig. 3. The same reference numerals as those used in respect of the first embodiment are reused for corresponding features of the second embodiment. Whereas the first embodiment is a double barrel cylinder lock, this embodiment is a thumb-turn cylinder lock as the internal lock actuator 9 is a thumb-turn mechanism 17 provided at the internal end of the cylinder body 4, instead of an internal barrel.

The cylinder lock 1 of the second embodiment also comprises a body 4 which comprises an internal side Sand an external side 6. The cylinder lock 1 is also configured to be installed in a door such that the internal side 5 and external side 6 of the cylinder lock 1 correspond, i.e. are on the same side of the door, to the internal and external sides of the door respectively.

The external side 6 of the body 4 of the second embodiment is substantially the same as that described with respect to the first embodiment, with the exceptions that in this embodiment no external barrel spacer 62 is provided and in that the external clutch has a shorter sprung finger 47 and that the external clutch 43 is rotationally coupled to the external barrel 13 by the same locking formations 43 that engage the corresponding locking formations provided in the external side 37 of the cam 7 (rather than a key and keyway), but the external side is otherwise identical. As the with first embodiment, the locking formations 43 are provided as two radially extending and diametrically opposed keys 43 which are slidingly received within corresponding diametrically opposed keyways 77 in the internal end of the external barrel 13.

A bridge portion of the body 4 adjoins the internal Sand external sides 6 of the body 4. A cam 7 is arranged between the internal Sand external 6 sides of the body 4. The cam 7 is arranged for rotation about the longitudinal axis (i.e. an axis extending from the internal side 5 5 to the external side 6) of the body 4 between a first rotational position of the cam corresponding to a locked configuration of the door and a second rotational position of the cam corresponding to an unlocked configuration of the door. A lug 51 provided on the cam is configured for actuating a locking mechanism (not shown) of the door when the cylinder lock 1 is installed in the door upon rotation of the cam about the longitudinal axis. The 10 rotational axis of the cam may also be referred to as the cam rotation axis or the cam axis.

The cam 7 itself comprises an internal side 36 and an external side 37, corresponding to the internal Sand external 6 sides of the cylinder lock body 4 respectively such that, when the cylinder lock 1 is installed in a door, the internal side 36 of the cam 7 is arranged closest to, or on the side of, the internal (or interior) side of the door and vice versa with respect to the external side 37 of the cam 7. At the extremities of the cam 7 along the cam axis are the cam internal end 11 and the cam external end 12 which are opposed and are spaced apart from each other.

As with the first embodiment, a chamfered, or in some embodiments a rounded, peripherally-extending or circumferentially-extending edge or surface 8 is provided on an outer circumferential surface of the cam 7 of the second embodiment also. The chamfered or rounded edge or surface 8 may also be referred to as a gradiated edge or surface in that the edge or surface has a gradient of more than zero but less than 90 degrees (for example 20, 30, 40, 45, 50, 55, 60, or 70 degrees) relative to the cam axis -indeed a chamfered edge 8 or rounded edge 8 are examples of a gradiated edge and each comprise a gradiated surface (albeit, for rounded edges, the gradient of the gradiated surface increases continuously in one axial direction). It should be noted that in this second embodiment, as well as in the first embodiment, the rounded or chamfered edge 8 may or may not always be provided but greatly assists in preventing the cam 7 from being removed from the cylinder lock 1 during an intrusion attack. The chamfered or rounded edge 8 faces towards the external side of the lock, i.e. the direction normal to a plane of the chamfer surface 8 or rounded surface 8 has a component (when extending outwardly, away from the lock body) which extends away from the cam 7 towards the external side 6 of the cylinder lock body 4.

The chamfered or rounded edge 8 is configured such that the edge 8 resists a pair of pliers or other such clamping tool being secured to the cam 7 as the nose of the pliers are caused to slide off of the cam 7 when they engage the angled surface of the chamfered edge 8.

Thus, the chamfered edge 8 provides a particularly effective means of preventing the cam 7 from being removed from the cylinder lock 1 during a snapping intrusion attack from the external side 6 of the cylinder lock body 4 in which a sacrificial portion 31 of the external side 6 of the cylinder lock body 4 has been snapped off. Preventing removal of the cam 7 is an effective way of preventing access to the locking mechanism provided within the door itself which is normally actuated by rotation of the cam 7 and upon engagement with the lug 51 of the cam 7.

The chamfered or rounded edge 8 may be provided at any location along the cam 7, for example it may be provided on the internal side 36 or the external side 37 of the cam 7 so long as it prevents a clamping tool from being secured to the cam during an external attack. Particularly advantageously however, the chamfered or rounded edge 8 may be provided at the external end 12 of the cam 7 as this prevents a clamping tool from being applied to the external end 12 of the cam 7 which is the end most readily accessible from the external side of the door and the end to which a greatest snapping bending moment may be applied during an attack, and is the end most likely to be attempted to be grasped by an attacker during an attack.

Rather than being rounded or chamfered, edge 8 may instead in other embodiments have one of many other forms provided that it has an angled peripherally or circumferentially extending surface which is angled towards the external side 6 of the cylinder lock body 4. By angled towards, it is meant that the direction normal to the plane of the angled surface has a component which extends away from the angled surface (that is, outwardly from the body 4) and towards the external side 6 of the cylinder lock body 4. The angle of this angled surface may vary continuously or smoothly along the cam axis, such as a rounded edge, or may have a constant angle, such as a chamfered edge.

When the edge 8 is a rounded edge, it may have a round radius of 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 11, 12, 13, 14, or 15mm, or more, or any 30 intermediate value therebetween or may be a range between any of these values.

When the edge 8 is a chamfered edge, it may have a chamfer angle of 20, 25, 30, 35, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 55, 60, 65 or 70 degrees as measured from the cam rotation axis, or any intermediate value therebetween or may be a range between any of 35 these values.

While the edge 8 in this embodiment extends around the entire outer perimeter or circumference of the cam 7 it may in other embodiments extend only partially around the outer perimeter or circumference, for example only 45, 60, 90, 120, 180, 240, 270, 320 degrees or some fraction or extent of the full perimeter or circumference of the cam 7.

Referring to the cylinder lock 1 of the second embodiment more generally now, the internal side 5 of the body 4 and the external side 6 of the body 4 each comprise a lock actuator 9, 10 configured to be actuatable from the internal and external side respectively of the door when the cylinder lock 1 is installed in the door. While the internal 9 and external lock actuators 10 may take many different forms, in the second embodiment they respectively comprise a thumbturn mechanism 17 and an external barrel 13 each rotatably received within the internal side Sand external side 6 respectively of the cylinder lock body 4 within an longitudinally extending throughbore 63, 64 provided in each of the internal side 5 and external side 6 of the body 4. The thumbturn mechanism 7 is located with respect to the body 4 by way of circlip 88 (Fig. 3) which sits in a circumferential groove 2 provided in the internal end of an axially extending shaft 18 of the thumbturn mechanism 17 and engages an externally-facing face 89 of the internal side 5 of the body 4. Similarly, the external barrel 13 is located with respect to the body 4 by way of circlip 59 which sits in a circumferential groove 104 provided in the internal end of the external barrel 13 and engages an internally-20 facing face of the external side 6 of the body 4.

The external barrel 13 comprises a set of sprung differ pins and tumblers 79 and a keyslot 14 for receiving a key 95 and, upon insertion of the key 95 in the keyslot 14, aligning the differ pins 79 along a shear plane of the external barrel barrel 13 for permitting rotation of the external barrel 13 about the longitudinal axis of the body 4 in the usual fashion and so will not be described in greater detail herein. The external barrel 13 also comprises anti-drill pins 72 and 73 aligned parallel to the diameter of the barrel 13 and spaced apart so as to be on opposing sides of the external keyslot 14. A further anti-drill pin 68 is provided in a radially extending aperture 82 in the external side 6 of the body 4.

The thumbturn mechanism 17 and external barrel 13 are selectively rotationally couplable and decouplable with or to the cam 7 such that rotation of the thumbturn mechanism 17, when rotationally coupled to the cam 7, causes rotation of the cam 7 about the cam axis and, similarly, such that rotation of the external barrel 13, when rotationally coupled to the cam 7, causes rotation of the cam 7 about the cam axis.

So that rotation of the thumbturn mechanism 17 may rotate the cam 7 when it is rotationally coupled to the cam 7, the external barrel 13 may be rotationally decoupled from the cam 7 when the thumbturn mechanism 17 is rotationally coupled to the cam 7. Similarly, so that rotation of the external barrel 13 may rotate the cam 7 when it is rotationally coupled to the cam 7, the thumbturn mechanism 17 may be rotationally decoupled from the cam 7 when the external barrel 15 is rotationally coupled to the cam 7.

A drive member 19 (which in the embodiment of Fig. 3 may be referred to as an internal clutch 35 as it selectively forms a rotational drive path between the thumbturn mechanism 17 and the cam 7) is arranged within and configured to slide along the throughbore 63 of the internal side 5 of the body 4. The internal clutch 35 provides the selective coupling and decoupling of the thumbturn mechanism 9 to the cam 7 via coupling element 28, i.e. it selectively forms or establishes the rotational drive path or connection between the thumbturn mechanism 17 and the cam 7. The internal clutch 35 is configured to selectively form (or establish) a rotational drive path between the thumbturn mechanism 17 and the cam 7 such that rotation of the thumbturn 15 causes rotation of the cam 7 when the rotational drive path is formed (or established). The drive path is formed when the internal clutch 35 is rotationally coupled to coupling 28 by engagement of locking formations 38 of the internal clutch 35 with corresponding locking formations 29 of the coupling 28. In this embodiment, the locking formations 38 are provided as flats which are arranged circumferentially around an axially extending projection of the internal clutch 35 and the locking formations of the coupling 28 are provided as corresponding flats which are arranged circumferentially around an axially extending aperture 109 of the coupling 28 which are configured to receive and engage with the flats of the internal clutch 35. The locking formations do not need to be flats (i.e. flat surfaces) but could be provided in any other suitable way.

The thumbturn mechanism 17 comprises a knob 92 for hand operation by a user. The knob 92 is affixed to an internal end of a shaft 18 via a grubscrew 93 which passes through a radially-extending hole 95 in the knob 92 and screws into a correspondingly threaded radially-extending hole 94 in the shaft 18. Other suitable means of attaching the knob 92 to the shaft 18 may instead by used and in some embodiments the knob 92 may be integrally formed with the shaft 18. Shaft 18 is slidingly received within a throughbore 63 provided in the internal side 5 of the body 4 so as to be configured to slide towards and away from (i.e. in an external direction and an internal direction) the cam 7.

A biasing means 40 (which may be referred to as a drive member biasing means or, especially in this embodiment, an internal clutch biasing means), comprising a pusher (here in the form of a rod) 101 and spring 20, biases the internal clutch 35 axially away from the shaft 18 and towards cam 7. The internal clutch 35 comprises locking formations 105 configured to engage correspondingly shaped locking formations 106 provided on the shaft 18 for rotationally coupling internal clutch 35 and shaft 18 upon engagement of the locking formations.

The internal clutch 35 comprises a plurality of diametrically-equispaced radially-extending 10 apertures 22 each configured to receive a respective blocking member 90. There are 6 such diametrically-equispaced apertures 22 is in this embodiment but any other suitable number of aperture may be used, for example 1, 2, 3, 4, 5, 7, 8, 9, 10 and so on.

At its external end, the internal clutch 35 comprises an axially extending projection 49 having a circumferential smooth surface 49 at the external tip of projection 49 and having a portion of its length being provided with locking formations which in this embodiment are in the form of diametrically-equispaced flats 38. In this embodiment, six flats 38 are used however any suitable number of flats 38 may instead be used, for example 3,4, 5, 7, 8, 9, 10 and so on.

Projection 49 is slidingly received by an aperture provided in an coupling element or coupling 28 (which may be referred to as an internal clutch coupling 28 in certain embodiments, for example in the embodiment of Fig. 3, where the drive member 19 is an internal clutch 35 configured to selectively form a rotational drive path with the coupling element 28 which in this embodiment may be referred to as an internal clutch coupling 28) for rotationally coupling the internal clutch 35 to the cam 7. The aperture of coupling 28 comprises locking formations 29 corresponding to the locking formations 38 provided on projection 49 (i.e. flats 38) such that the internal clutch 35 is rotationally coupled with the coupling element 28 by engagement of the internal clutch locking formations 38 with the coupling locking formations 29. In this embodiment, the coupling locking formations 29 comprise a plurality of diametrically equispaced flats 29. In this embodiment, six flats 29 are used however any suitable number of flats 29 may instead be used, for example 3, 4, 5, 7, 8,9, 10 and so on.

The coupling 28 is affixed to (and axially located with respect to), but rotationally decoupled 35 from, the internal side 5 of the body 4 by a pin 97 (Fig. 4B) biased by spring 98 which is configured to protrude from a radially extending aperture 99 provided in the internal side 5 of body 4. Pin 97 is slidingly received within circumferential groove 28 provided in the outer circumferential surface of coupling 28. Pin 97 can be any suitable shape or form for slidingly engaging with circumferential groove 28.

The coupling 28 comprises locking formations 107 at its external end which are configured 5 to engage with corresponding locking formations 30 provided in the cam 7 such that the cam 7 is rotationally coupled to coupling 28 by engagement of the respective locking formations 107, 30.

The cam 7 is affixed to or secured to coupling 28 by an attachment means 52 which in this embodiment takes the form of a snap ring 58 which sits in a circumferential groove 54 (Fig. 4F) provided in an inner annular surface 55 of the cam 7 and in a corresponding outer circumferential groove 28 provided in an outer circumferential surface at the external end of the coupling 28. Thus, the attachment means 52 is not easily accessible from the external side 6 of the body 4 for removal during an attack as the cam 7 covers, at least a portion of, the attachment means, although in this example the cam 7 comprises a partially circumferentially extending access window 57 at the internal end 11 of the cam 7 for providing access to the attachment means 52 for removing or installing the attachment means 52, at least in certain rotational positions of the cam 7. Thus cam 7 is securely attached to internal side 5 of the body 4 via the coupling 28 (which is itself attached to the internal side 5 of the body 4 by pin 97 riding within circumferential groove 100 of the coupling 28) so as to hinder removal of the cam during an external attack. The cam 7 is thus axially retained to the coupling 28 by the attachment means 52 while not restricting or restraining rotational movement of the cam 7 with respect to the body 4.

By preventing the cam 7 from being removed during an attack in this way, a particularly secure cylinder lock 1 is provided as the inner locking mechanism of the door is even more difficult to access. Thus, the rounded or chamfered edge 8 works in a synergistic way with the attachment means 52 for providing yet an even more secure cylinder lock 1 as, not only does the attachment means 52 make it difficult to remove the cam 7 as it is secured by the attachment means 52 to the internal side 5 of the body 4, but removal of the cam 7 is made yet even more difficult by the chamfered or rounded edge 8 as this prevents an attacker from securely grasping the cam 7 by preventing, or at least hindering, secure attachment of a clamping tool such as a pair of pliers to the cam 7.

The internal side 5 of the body 4 also comprises a security mechanism which comprises a blocking member 23 (here in the form of a pin 23, although any other suitable form may instead be used) which is biased to protrude from a radially extending aperture 24 into the throughbore 63. The diametrically-equispaced radially-extending apertures 22 of the internal clutch 35 are configured to receive the blocking member 23 such that, when the blocking member 23 engages with one of the plurality of diametrically-equispaced radially-extending apertures 22, the internal clutch becomes rotationally coupled to, or locked to, the internal side 5 of the body 4. When the internal clutch 35 is in an axial position along throughbore 63 in which the blocking member 23 is engaged with one of the plurality of diametrically-equispaced radially-extending apertures 22, the locking formations 38 on the internal clutch 35 are in engagement with the corresponding locking formations 29 on the coupling 28 such that the internal clutch 35 and cam are rotationally coupled to each other (as the coupling 28 is maintained in rotational coupling with the cam 7). Thus, via the coupling 28 and the internal clutch 35, the cam 7 is locked to the internal side 5 of the cylinder body 4 when the blocking member 23 is in engagement with one of the diametrically-equispaced radially-extending apertures 22. It will be appreciated that (after removal of the sacrificial portion 31, causing the internal clutch 35 to move axially towards the cam 7 to engage with the cam 7 so as to rotationally couple the cam 7 to the internal clutch 35) blocking member 23 will only engage one of the apertures 22 at a certain number of predefined rotational positions of the internal clutch 35 according to the number of apertures 22 provided. Here, six such apertures 22 are provided and so the internal clutch 35 needs to be rotated no more than 60 degrees before the blocking member 35 engages one of the apertures 22.

The engagement of blocking member 23 with aperture 22 also provides a stop such that the internal clutch 35 is restrained or prevented from moving axially away from the cam 7 when the blocking member 23 is in engagement with one of the apertures 22 such that the internal clutch 35 is held in non-disengageable engagement with the cam 7, thereby nondisengagably rotationally coupling the cam 7 to the internal clutch 35 and thereby to the internal side 5 of the body 4, thereby rotationally locking the cam 7 to the internal side 5 of the body 4 to prevent rotation of the cam 7 with respect to the internal side of the body 4. This is particularly advantageous as it prevents an attacker from disengaging the internal clutch 35 from rotational coupling with the cam 7 by simply pushing on the internal clutch 35 through the cam aperture 48 from the external side of the lock 1 once the sacrificial portion 31 has been removed during a snapping intrusion attack.

While the engagement of the blocking member 23 with aperture 22 prevents internal clutch 35 35 from moving axially away from the cam 7, the security mechanism also comprises a second blocking member 26 which is biased to protrude from, and into throughbore 63, its own radially-extending aperture 27 in the internal side 5 of the body 4 in order to provide additional capacity of resisting the internal clutch being attempted to be pushed out of disengagement with the coupling 29 by an attacker by further preventing the internal clutch 35 from moving axially away from the cam 7. The first 23 and second 26 blocking members 22 are configured so as to simultaneously engage the internal clutch 35 at a predetermined 5 axial position of the internal clutch 35 along the throughbore 63. At said predetermined axial position, blocking member 26 (here in the form of a pin 26, although other such suitable forms may be used instead), protrudes from aperture 2750 as to engage a stop 25 provided in the internal clutch. Here the stop 25 is provided as a circumferentially extending groove or lip 25 provided in the outer circumferential surface of the internal clutch, although other 10 such suitable features may instead be used as a stop surface.

The internal clutch 35 is biased indirectly against the sacrificial portion 31 by the internal clutch biasing means 40 such that removal of the sacrificial portion 31 causes the internal clutch 35 to move axially towards the cam 7 such that the internal clutch 35 becomes rotationally coupled to the coupling 28, and to a predetermined axial position within the throughbore 63 such that the first blocking member 23 is aligned with the plurality of circumferentially equispaced apertures 22 such that, when the internal clutch 35 is rotated (by forced rotation of the cam by an attacker), the first blocking member 23 is caused to protrude from its aperture 24 by its spring and into engagement with one of the apertures 22, holding the internal clutch 35 in non-disengageable engagement and nondisengageable rotational coupling with the coupling 28 which is itself held in nondisengageable engagement and non-disengageable rotational coupling with the cam 7, such that the internal clutch 35 is rotationally and axially locked to the cam 7. At this same predetermined axial position of the internal clutch 35, the second blocking member is released from its aperture 27 and engages stop 25 of the internal clutch 35 for further preventing the internal clutch 35 from moving axially away from the cam 7 and thereby becoming rotationally decoupled from the coupling 28.

The external clutch 42 comprises a base 46 and a sprung finger 47 biased apart from each 5 other by external clutch spring 45. The external clutch 42 is slidingly received within the external barrel 13 by way of a radially-projecting locking formations 43 provided on the external clutch 42 which ride along axially extending cutouts 77 provided in the internal end of the external barrel 13 so that the external clutch 42 is configured to slide axially away and toward the cam 7. Thus, the external clutch 42 is permanently rotationally coupled to 10 the external barrel 13.

Locking formations 43 provided on the base 46, in this example in the form of diametrically opposed and radially extending lugs or wings 43 are configured to engage with corresponding locking formations (not shown) provided in the external side 37 of the cam 7 so that the cam 7 and external clutch 42 are rotationally coupled together when the locking formations 43 of the external clutch 42 are engaged with their corresponding locking formations on the cam 7.

The sprung-finger 47 comprises an axially extending projection 47. The cam aperture 48 is configured to receive this projection 47 such that the projection 47 is able to protrude sufficiently therethrough so as to be able to contact the projection 49 of the internal clutch 35 so as to be able to push the internal clutch 35 out of engagement with the coupling 28, and thereby rotationally decouple the intemal clutch 35, and thereby the internal barrel 15, with the cam 7, when a key is inserted into the external keyslot 14. A external barrel spacer 62 may also be provided as an optional feature, depending on the length of the external side 6 of the body 4.

Operation of the cylinder lock of the second embodiment will now be described with reference to Figs 4A to 4J.

Figures 4A and 4B show the cylinder lock in the at rest position in which the thumbturn mechanism 17 is rotationally decoupled from the internal clutch 35 and in which a key 95 has not been inserted into the external keyslot 14. The internal clutch biasing means 40 biases the internal clutch 35 into engagement with the coupling 28 such that the locking formations 38 on the internal clutch 35 are maintained in engagement with the corresponding locking formations 29 provided in an axially extending aperture 109 of the coupling 28 which extends from the internal face of the coupling 28. Thus, as the coupling 28 is rotationally coupled to the cam 7 by way of engagement of the coupling's cam locking formations 107 with their respective locking formations 30 provided in the cam 7, the cam 7 is rotationally coupled to internal clutch 35. The internal clutch 35 is rotationally decoupled from the internal side 5 of the body 4 as blocking member 23 remains recessed within its aperture 24 and does not engage with one of the circumferentially eguispaced apertures 22 in the internal clutch 35. Thus, cam 7 is rotationally decoupled from the internal side 5 of the body 4.

As internal clutch 35 is biased by the internal clutch biasing means 40, an axially extending projection at the external end thereof, passes through the aperture of the coupling 28 and pushes directly on the end of the sprung finger 47, through the cam aperture 48 against the bias of external clutch spring 45 and, by way of the external clutch spring 45, the external clutch base 46 is biased axially away from the cam 7 such that the external clutch 42 is held out of locking engagement with the cam 7 such that the cam 7 is rotationally decoupled from the external clutch 42 and so thereby the cam 7 rotationally decoupled from the external barrel 13. Nevertheless the external barrel 13 is prevented from rotation due to the external pin and tumbler arrangement 79 being misaligned with its shear plane. Although the external clutch base 46 is biased away from the sprung finger 75, they are only able to move a predetermined distance apart from each other and so the external clutch locking formations 43 provided on the base 46 are unable to engage the corresponding locking formations on external side 37 of the cam 7. Thus the cam 7 is not rotationally locked to either the internal 5 or external 6 sides of the body 4 in this configuration and is free to rotate, although it is rotationally disengaged from both the thumbturn mechanism 17 as well as the external barrel 13.

The internal clutch biasing means 40 biases the internal clutch 35 towards the cam such that the axially extending projection 49 of the internal clutch 35 pushes directly against the sprung finger 47 extending through the cam aperture 48, causing the sprung finger 47 to abut against the end of the external keyslot 14 (or packer 62 instead in embodiments in which packer 62 is present). Thus, the internal clutch 35 is unable to move any further in the external direction in this configuration. As such, the internal clutch biasing means 40 now serves to bias the thumbturn mechanism 17 in the internal direction and away from the internal clutch 35 such that the thumbturn locking formations 106 are disengaged from the corresponding locking formations provided on the internal side of the internal clutch 35 such that the thumbturn mechanism 17 is rotationally decoupled with or disengaged from the internal clutch 35. Thus, in this configuration, there is no load transfer path between the thumbturn mechanism 17 and the internal clutch 35 and so the internal clutch 35 can be rotated freely within the internal side 5 of the body 4 by knob 92.

Also in this position of the internal clutch 35, the first blocking member 23 and second blocking member 26 are both depressed within their respective apertures 24, 27 by the outer circumferential surface of the internal clutch 35 being positioned over them, i.e. the first 23 and second 26 blocking members are not aligned with their respective aperture 24 and groove 25 respectively. Thus, the security mechanism, of which the first 23 and second 26 blocking members form a part of, is disengaged.

Pin 97 is slidingly received within circumferential groove 96 in the coupling 28 so as to be configured to slide around the circumference of the coupling 28 such that the coupling is secured to, or affixed to, the internal side 5 of the body 4 but is also able to be rotated within the throughbore 64. Thus, the coupling 28 is rotatably received within and affixed to the throughbore 64 of the internal side 5 of the body 4.

Turning now to Figures 4C and 4D, these figures show the configuration of the cylinder lock 1 of the second embodiment when the thumbturn mechanism 17 has been pushed axially by a user against the biasing force provided by the internal clutch biasing means 40 towards the cam 7 such that the thumbturn mechanism locking formations 106 provided on the thumbturn shaft 18 engage the corresponding locking formations 105 provided on the internal clutch 35. Thus, the thumbturn mechanism 17 is rotationally coupled to the internal clutch 35 such that rotation of the thumbturn mechanism 17 causes rotation of the clutch 35. Furthermore, as in the configuration of 4A, the axially extending projection of 21 of the thumbturn shaft 18 is slidingly received within an axially extending aperture 90 of the internal clutch 35. As the locking formations 38 on the axially extending projection 49 of the internal clutch 35 are still biased into locking engagement with the corresponding locking formations 29 provided on the coupling 28, the internal clutch 35 is rotationally coupled to the coupling 28. As the locking formations 107 on the coupling are in locking engagement with the corresponding locking formations 30 provided on the internal side of the cam 7, the coupling 28 is rotationally coupled to the cam 7. Thus, by engagement of the thumbturn mechanism 17 with the internal clutch 35 upon the thumbturn mechanism being moved axially towards the internal clutch 35, a rotational drive path is established between the thumbturn mechanism 17 and the cam 7, through internal clutch 35 and coupling 28, such that rotation of the thumbturn mechanism 17 causes rotation of the cam 7. Thus, the thumbturn mechanism 17 is operably connected to the cam 7.

The axially extending projection 49 of the internal clutch 35 remains biased directly against the sprung finger 47 of the external clutch 42, holding the external clutch 42 out of rotational coupling with the cam 7 (as the locking formations 43 of the external clutch 42 are held out of locking engagement with the corresponding locking formations [not shown] provided in 5 the external side 37 of the cam 7). Thus, the internal clutch 35 is rotationally coupled to the cam 7 while at the same time the external clutch 42 is rotationally decoupled from the cam 7. Thus, it can be seen that the external clutch 42 is biased out of engagement with the cam 7 by the internal clutch biasing means 40. Thus, the cam 7 is rotationally decoupled from the external barrel 13 and so is free to rotate upon rotation of the thumbturn mechanism 17. 10 As the internal clutch 35 is in the same axial position as that in Fig. 4A, the security mechanism remains undeployed -that is the first 23 and second 26 blocking members remain depressed within their respective apertures 24, 27 by the outer circumferential surface of the internal clutch 35.

Figures 4E and 4F show the configuration of the cylinder lock 1 of the second embodiment when a key 95 is inserted into the external barrel key slot 14. The tip of the key 95 pushes against the external clutch 42, causing the external clutch 42 to move axially in the internal direction towards the cam 7 such that the sprung finger 47 protrudes further through cam aperture 48. The external clutch 42 is caused to move sufficiently towards the cam 7 that the locking formations 43 of the external clutch 42 engage with the corresponding locking formations (not shown) provided on the external side 37 of the cam 7 and thus the external clutch 42 becomes rotationally coupled to the cam 7.

As sprung finger 47 protrudes, or passes, further through cam aperture 48, the sprung finger 47 pushes directly against the axially extending projection 49 of the internal clutch 35 and causes the internal clutch 35 to move away from the cam 7 in the internal direction, against the biasing force provided by the internal clutch biasing means 40, to a sufficient extent that the locking formations 38 provided on the axially-extending projection 49 of the internal clutch 35 are caused to become disengaged from the corresponding locking formations 29 provided within the axially-extending aperture 109 of the coupling 28 (although the axially extending projection 49 remains slidingly received within the axially-extending aperture 109 of the coupling 28). Thus, the internal clutch 35 becomes rotationally decoupled from the cam 7. The internal clutch biasing means 40 biases the locking formations on the thumbturn mechanism 17 out of engagement with the internal clutch such that the thumbturn mechanism 17 is rotationally decoupled from the internal clutch 35.

Insertion of the key 95 also causes the external pin and tumbler arrangement 79 to align with its shear plane such that the external barrel 13 becomes rotationally decoupled from the external side 6 of the body 4. Thus, insertion of the key 95 into the external keyslot 14 causes the external barrel 13 to become rotationally decoupled from the external side 6 of the body 4, causes the external clutch to become rotationally coupled to the cam 7, and causes the internal clutch to become rotationally decoupled from the coupling 28, rotation of the key 95 causes the external barrel 13 to rotate, which causes the external clutch 42 to rotate, which then causes the cam 7 to rotate. Thus, insertion of the key 95 into the external keyslot 14 causes the external barrel 13 to become operatively connected to the cam 7 such that rotation of the external barrel via key 95 causes rotation of the cam 7. Thus a rotational drive path is establish between the external barrel 13 and the cam 7. The cam 7 can therefore be rotated between its first and second positions for actuating a locking means of the door by rotation of the key 95.

Figures 4G and 4H show the configuration of the cylinder lock 1 of the second embodiment when the sacrificial portion 31 of the external side 6 of the body 4 has been removed during a snapping intrusion attack from the external side of the lock 1. The sacrificial portion 31 has been snapped at the pre-weakened portion 32 provided by the breakaway slot 33 and has been removed, along with the external clutch 42.

As the sprung finger 47 has in this configuration been removed during the attack, there is nothing stopping the internal clutch biasing means 40 from pushing the internal clutch 35 further towards the coupling 28 and so the internal clutch 35 slides sufficiently towards the coupling 28 such that the first 23 and second 26 blocking members are uncovered by the internal clutch 35 such that simultaneously the first blocking member 23 is axially aligned with the plurality of circumferentially equispaced aperture 22 and the second blocking member 26 is aligned with the groove 25 such that the second blocking member 26 is released from its aperture 27 and engages the stop 25 provided in the internal clutch 35. Thus, the engagement of the second blocking member 26 with the stop 25 prevents the internal clutch 35 from being pushed out of locking engagement with the cam 7, for example from being pushed from the external side of the lock 1 in the internal direction and so the internal clutch 35 is in non-disengageable engagement with the cam 7, via coupling 38.

While the first blocking member 23 is axially aligned with the plurality of circumferentially 35 equispaced apertures 22, depending of the rotational position of the internal clutch 35, the first blocking member 23 may or may not be rotationally aligned with one of the plurality of circumferentially equispaced apertures 22 and so, if the first blocking member 23 is misaligned with one of the plurality of circumferentially equispaced apertures 22, it remains depressed within its aperture 24 by the circumferential outer surface of the internal clutch 35). If the internal clutch 35 is rotationally aligned with one of the plurality of circumferentially equispaced apertures 22, the first blocking member 23 is released from its aperture and engages the one of the plurality of circumferentially equispaced apertures 22 it is aligned with such that the first blocking member 23 is received within the aperture 22. If the internal clutch 35 is not already rotationally aligned with one of the plurality of circumferentially equispaced apertures 22, it will become so as, not being able to remove cam 7 due to the attachment means 58 affixing the cam 7 to the coupling 28, the cam 7 is forcibly rotated by the attacker in attempting to actuate the door locking mechanism. Thus, first 23 and second 26 blocking members become engaged with the internal clutch 35 -the first blocking member 23 preventing both rotation of the cam 7 and also axial movement of the internal clutch 35 so as to prevent rotational decoupling of the internal clutch from the cam 7; the second blocking member 26 preventing only axial movement of the internal clutch 35 so as to prevent rotational decoupling of the internal clutch from the cam 7. Thus, as the internal clutch 35 remains rotationally coupled to the coupling 28 and as the coupling is rotationally coupled to the cam 7, the cam 7 is rotationally and axially locked with respect to the internal side 5 of the body 4 by engagement of blocking members 23 and 26 with apertures 22 and stop 25.

Removal of the cam 7 from the internal side 5 of the body 4 by the attacker is prevented by the attachment means 52 which securely axially affixes the cam 7 to the coupling 28 (but which does not rotationally couple the cam 7 to the coupling 28), the coupling 29 itself being securely axially affixed to the internal side 5 of the body 4 via the sliding engagement of pin 97 about circumferential groove 96 (Fig. 4B) which does not rotationally couple the coupling 28 to the internal side 5 of the body 4. The chamfered or rounded edge 8 of the cam 7 prevents the cam 7 from being gripped or grasped, for example by a clamping tool such as a pair of pliers, by an attacker for removal. Thus the cam 7 prevents access to the locking mechanism of the door which would otherwise be accessible if the cam 7 were able to be removed, thereby preventing the door from being opened.

As the internal clutch 35 has advanced further towards the cam 7 in this security configuration, releasing the second blocking member 26 and, depending on the rotational position of the internal clutch 35, also the first blocking member 23, the cam 7 has become non-disengageably rotationally coupled to the internal side 5 of the body 1. Thus, the cam 7 is prevented from rotation. Anti-drill pin 68 provided in the body 4 between the aperture 24 and the breakaway slot 33 prevents drilling from the external side to remove the first 23 or second 26 blocking member, or pin 97.

Figures 41 and 4J show the configuration of the cylinder lock 1 of the second embodiment when it is desired to unlock the door from the inside/interior of the room/building/space after a snapping intrusion attack. The thumbturn mechanism 17 is pressed in, towards the cam 7, causing the thumbturn shaft 18 to slide along throughbore 63 provided in the internal side 5 of the body 4 until circlip 88 engages an end face or shoulder of the circumferential groove 103 provided in the thumbturn shaft 18. In this position of the thumbturn mechanism 17, the locking formations 106 provided on the shaft 18 are in locking engagement with their respective locking formations 105 provided on the internal clutch 35 such that the thumbturn mechanism 17 is rotationally coupled to the internal clutch 35. The internal clutch 35 is in the same position as that shown in Figs 4G and 4H and so remains biased into engagement with, and rotationally coupled to, the coupling 28. Thus, the thumbturn mechanism 17 is rotationally coupled to the cam 7 such that there exists a rotational drive path between the thumbturn mechanism 17 and the cam 7. So that the internal clutch 35, and thereby the cam 7, may be rotated by the thumbturn mechanism 17, the axially-extending projection 49 of the shaft 18 comprises a chamfered or rounded edge 102 partway therealong, adjoining a first portion of the axially-extending projection 49 to a second portion of the axially-extending projection 49 which has a smaller diameter than the first portion, the second portion being arranged closer to internal clutch 35 than the first portion so as to form a ramped or inclined surface 102. Thus, when the thumbturn mechanism 17 is pressed into the lock (to the position shown in Fig. 41), each pin 90 arranged within each of the plurality of circumferentially equispaced apertures 22 rides along the ramped or inclined surface 102 so as to move radially outwards from the cam axis and to depress first blocking member 23 back into its aperture 24 against the biasing force provided by spring 66, thereby causing the first blocking member 23 to become disengaged from the one of the plurality of circumferentially equispaced apertures 22 it was previously in engagement with. Thus, the internal clutch 35 is now rotationally decoupled from the internal side 5 of the body 4 and rotation of the thumbturn mechanism 17 causes the cam 7 to be rotated so as to unlock the door.

The second blocking member 26 remains in engagement with the stop 25 provided on the internal clutch 35, however this is not problematic because, as the sacrificial portion 31 of the lock 1 has been removed (and the external barrel 13 and external clutch 42 therewith), the internal clutch 35 is no longer required to move in the internal direction so as to rotationally decouple the internal clutch 35 from the coupling 28.

A third embodiment of a cylinder lock according to the present invention is shown in exploded view in Fig. 5. The same reference numerals as those used in respect of the second embodiment are reused for corresponding features of the third embodiment.

The third embodiment is generally identical to the second embodiment with the exception that the locking formations of the drive member 19 extend slightly further along the axially-extending projection 49 such that the drive member 19 is permanently rotationally coupled to the coupling 28 irrespective of the axial position of the drive member 19 relative to the coupling 28. In contrast, in the second embodiment, the drive member 19 (which in the second embodiment may be referred to as an internal clutch 35) is selectively rotationally couplable to the coupling 28 as the locking formations of the drive member 19 do not extend as far as they do in the third embodiment and so, in the second embodiment, the drive member 19 may be moved axially, in the direction away from the cam, to such an extent that the locking formations 38 of the drive member 19, which provide the rotational coupling between the drive member 19 and the coupling 28) no longer engage with their corresponding locking formations 29 of the coupling 28.

The cylinder lock 1 of the third embodiment also comprises a body 4 which comprises an internal side 5 and an external side 6. The cylinder lock 1 is also configured to be installed in a door such that the internal side 5 and external side 6 of the cylinder lock 1 correspond, i.e. are on the same side of the door, to the internal and external sides of the door respectively.

The external side 6 of the body 4 of the third embodiment is substantially the same as that described with respect to the second embodiment in that no external barrel spacer 62 is provided and in that the external clutch has a shorter sprung finger 47 and that the external clutch 43 is rotationally coupled to the external barrel 13 by the same locking formations 43 that engage the corresponding locking formations provided in the external side 37 of the cam 7. As the with first and second embodiments, the locking formations 43 are provided as two radially extending and diametrically opposed keys 43 which are slidingly received within corresponding diametrically opposed keyways 77 in the internal end of the external barrel 13.

A bridge portion of the body 4 adjoins the internal Sand external sides 6 of the body 4. A cam 7 is arranged between the internal Sand external 6 sides of the body 4. The cam 7 is arranged for rotation about the longitudinal axis 0.e. an axis extending from the internal side to the external side 6) of the body 4 between a first rotational position of the cam corresponding to a locked configuration of the door and a second rotational position of the cam corresponding to an unlocked configuration of the door. A lug 51 provided on the cam is configured for actuating a locking mechanism (not shown) of the door when the cylinder lock 1 is installed in the door upon rotation of the cam about the longitudinal axis or rotational axis of the cam between the first and second rotational positions of the cam. The rotational axis of the cam may also be referred to as the cam rotation axis or the cam axis.

The cam 7 itself comprises an internal side 36 and an external side 37, corresponding to the internal 5 and external 6 sides of the cylinder lock body 4 respectively such that, when the cylinder lock 1 is installed in a door, the internal side 36 of the cam 7 is arranged closest to, or on the side of, the internal (or interior) side of the door and vice versa with respect to the external side 37 of the cam 7. At the extremities of the cam 7 along the cam axis are the cam internal end 11 and the cam external end 12 which are opposed and are spaced apart from each other.

As with the first and second embodiments, a chamfered, or in some embodiments a rounded, peripherally-extending or circumferentially-extending edge or surface 8 is provided on an outer circumferential surface of the cam 7 of the third embodiment also. The chamfered or rounded edge or surface 8 may also be referred to as a gradiated edge or surface in that the edge or surface has a gradient of more than zero but less than 90 degrees (for example 20, 30, 40, 45, 50, 55, 60, or 70 degrees) relative to the cam axis -indeed a chamfered edge 8 or rounded edge 8 are examples of a gradiated edge and each comprise a gradiated surface (albeit, for rounded edges, the gradient of the gradiated surface increases continuously in one axial direction). It should be noted that in this third embodiment, as well as in the first and second embodiments, the rounded or chamfered edge 8 may or may not always be provided but greatly assists in preventing the cam 7 from being removed from the cylinder lock 1 during an intrusion attack. The chamfered or rounded edge 8 faces towards the external side of the lock, i.e. the direction normal to a plane of the chamfer surface 8 or rounded surface 8 has a component (when extending outwardly, away from the lock body) which extends away from the cam 7 towards the external side 6 of the cylinder lock body 4. The chamfered or rounded edge 8 is configured such that the edge 8 resists a pair of pliers or other such clamping tool being secured to the cam 7 as the nose of the pliers are caused to slide off of the cam 7 when they engage the angled surface of the chamfered edge 8. Thus, the chamfered edge 8 provides a particularly effective means of preventing the cam 7 from being removed from the cylinder lock 1 during a snapping intrusion attack from the external side 6 of the cylinder lock body 4 in which a sacrificial portion 31 of the external side 6 of the cylinder lock body 4 has been snapped off. Preventing removal of the cam 7 is an effective way of preventing access to the locking mechanism provided within the door itself which is normally actuated by rotation of the cam 7 and upon engagement with the lug 51 of the cam 7.

Rather than being rounded or chamfered, edge 8 may instead in other embodiments have one of many other forms provided that it has an angled peripherally or circumferentially extending surface which is angled towards the external side 6 of the cylinder lock body 4. By angled towards, it is meant that the direction normal to the plane of the angled surface has a component which extends away from the angled surface (that is, outwardly from the body 4) and towards the external side 6 of the cylinder lock body 4. The angle of this angled surface may vary continuously or smoothly along the cam axis, such as a rounded edge, or may have a constant angle (i.e. is flat), such as a chamfered edge.

When the edge 8 is a rounded edge, it may have a round radius of 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 11, 12, 13, 14, or 15mm, or more, or any intermediate value therebetween or may be a range between any of these values.

When the edge 8 is a chamfered edge, it may have a chamfer angle of 20, 25, 30, 35, 40, 30 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 55, 60, 65 or 70 degrees as measured from the cam rotation axis, or any intermediate value therebetween or may be a range between any of these values While the edge 8 in this embodiment extends around the entire outer perimeter or 35 circumference of the cam 7 it may in other embodiments extend only partially around the outer perimeter or circumference, for example only 45, 60, 90, 120, 180, 240, 270, 320 degrees or some fraction or extent of the full perimeter or circumference of the cam 7.

Referring to the cylinder lock 1 of the third embodiment more generally now, the internal side 5 of the body 4 and the external side 6 of the body 4 each comprise a lock actuator 9, 10 configured to be actuatable from the internal and external side respectively of the door when the cylinder lock 1 is installed in the door. While the internal 9 and external lock actuators 10 may take many different forms, in the third embodiment they respectively comprise a thumbturn mechanism 17 and an external barrel 13 each rotatably received within the internal side Sand external side 6 respectively of the cylinder lock body 4 within an longitudinally extending throughbore 63, 64 provided in each of the internal side Sand external side 6 of the body 4. The thumbturn mechanism 7 is located with respect to the body 4 by way of circlip 88 (Fig. 5) which sits in a circumferential groove 2 provided in the internal end of an axially extending shaft 18 of the thumbturn mechanism 17 and engages an externally-facing face 89 of the internal side 5 of the body 4. Similarly, the external barrel 13 is located with respect to the body 4 by way of circlip 59 which sits in a circumferential groove 104 provided in the internal end of the external barrel 13 and engages an internally-facing face of the external side 6 of the body 4.

The thumbturn mechanism 17 and external barrel 13 are selectively rotationally couplable and decouplable with or to the cam 7 such that rotation of the thumbturn mechanism 17, when rotationally coupled to the cam 7, causes rotation of the cam 7 about the cam axis and, similarly, such that rotation of the external barrel 13, when rotationally coupled to the cam 7, causes rotation of the cam 7 about the cam axis. In this way, the cam 7 may be rotated between first and second rotational positions respectively corresponding to locked and an unlocked configurations of the door (i.e. of the door locking means).

A drive member 19 is arranged within and configured to slide along the throughbore 63 of the internal side 5 of the body 4. In this third embodiment, the drive member 19 does not rotationally decouple from the coupling 29 and so there is a permanent rotational drive path between the drive member 19 and the cam 7. The drive path is formed by engagement of locking formations 38 of the drive member 19 with corresponding locking formations 29 of the coupling 28. In this embodiment, the locking formations 38 are provided as flats which are arranged circumferentially around an axially extending projection of the drive member 19 and the locking formations of the coupling 28 are provided as corresponding flats which are arranged circumferentially around an axially extending aperture 109 of the coupling 28 which are configured to receive and engage with the flats of the drive member 19. The locking formations do not need to be flats (i.e. flat surfaces) but could be provided in any other suitable way.

A biasing means 40 (which may be referred to as a drive member biasing means), comprising a pusher (here in the form of a rod) 101 and spring 20, biases the drive member 19 axially away from the shaft 18 and towards cam 7. As mentioned above, the drive member 19 comprises locking formations 105 configured to engage correspondingly shaped locking formations 106 provided on the shaft 18 for rotationally coupling drive member 19 and shaft 18 upon engagement of the locking formations.

The drive member 19 comprises a plurality of diametrically-equispaced radially-extending 35 apertures 22 each configured to receive a respective blocking member 90. There are 6 such diametrically-equispaced apertures 22 is in this embodiment but any other suitable number of aperture may be used, for example 1, 2, 3, 4, 5, 7, 8, 9, 10 and so on.

At its external end, the drive member 19 comprises an axially extending projection 49 having a circumferential smooth surface 49 at the external tip of projection 49 and having a portion of its length being provided with locking formations which in this embodiment are in the form of diametrically-equispaced flats 38. In this embodiment, six flats 38 are used however any suitable number of flats 38 may instead be used, for example 3,4, 5, 7, 8, 9, 10 and so on.

Projection 49 is slidingly received by an aperture provided in an coupling element or coupling 28 for rotationally coupling the drive member 19 to the cam 7. The aperture of coupling 28 comprises locking formations 29 corresponding to the locking formations 38 provided on projection 49 (i.e. flats 38) such that the drive member 19 is rotationally coupled with the coupling element 28 by engagement of the drive member locking formations 38 with the coupling locking formations 29. In this embodiment, the coupling locking formations 29 comprise a plurality of diametrically equispaced flats 29. In this embodiment, six flats 29 are used however any suitable number of flats 29 may instead be used, for example 3, 4, 5, 7, 8, 9, 10 and so on.

The coupling 28 is affixed to (and axially located with respect to), but rotationally decoupled from, the internal side 5 of the body 4 by a pin 97 (Fig. 6B) biased by spring 98 which is configured to protrude from a radially extending aperture 99 provided in the internal side 5 of body 4. Pin 97 is slidingly received within circumferential groove 28 provided in the outer circumferential surface of coupling 28. Pin 97 can be any suitable shape or form for slidingly engaging with circumferential groove 28.

The coupling 28 comprises locking formations 107 at its external end which are configured to engage with corresponding locking formations 30 provided in the cam 7 such that the cam 7 is rotationally coupled to coupling 28 by engagement of the respective locking formations 107, 30.

The cam 7 is affixed to or secured to coupling 28 by an attachment means 52 which in this embodiment takes the form of a snap ring 58 which sits in a circumferential groove 54 (Fig. 6F) provided in an inner annular surface 55 of the cam 7 and in a corresponding outer circumferential groove 28 provided in an outer circumferential surface at the external end of the coupling 28. Thus, the attachment means 52 is not easily accessible from the external side 6 of the body 4 for removal during an attack as the cam 7 covers and therefore obstructs, at least a portion of, the attachment means, although in this example the cam 7 comprises a partially circumferentially extending access window 57 at the internal end 11 of the cam 7 for providing access to the attachment means 52 for removing or installing the attachment means 52, at least in certain rotational positions of the cam 7. Thus cam 7 is securely attached to internal side 5 of the body 4 via the coupling 28 (which is itself attached to the internal side 5 of the body 4 by pin 97 riding within circumferential groove 100 of the coupling 28) so as to hinder removal of the cam during an external attack. The cam 7 is thus axially retained to the coupling 28 by the attachment means 52 while not restricting or restraining rotational movement of the cam 7 with respect to the body 4.

The internal side 5 of the body 4 also comprises a security mechanism which comprises a blocking member 23 (here in the form of a pin 23, although any other suitable form may instead be used) which is biased to protrude from a radially extending aperture 24 into the throughbore 63. The diametrically-equispaced radially-extending apertures 22 of the drive member 19 are configured to receive the blocking member 23 such that, when the blocking member 23 engages with one of the plurality of diametrically-equispaced radially-extending apertures 22, the drive member 19 becomes rotationally coupled to, or locked to, the internal side 5 of the body 4. When the drive member 19 is in an axial position along throughbore 63 in which the blocking member 23 is engaged with one of the plurality of diametricallyequispaced radially-extending apertures 22, the locking formations 38 on the drive member 19 are in engagement with the corresponding locking formations 29 on the coupling 28 such that the drive member 19 and cam are rotationally coupled to each other (as the coupling 28 is maintained in rotational coupling with the cam 7). Thus, via the coupling 28 and the drive member 19, the cam 7 is locked to the internal side 5 of the cylinder body 4 when the blocking member 23 is in engagement with one of the diametrically-equispaced radially-extending apertures 22. It will be appreciated that (after removal of the sacrificial portion 31, causing the drive member 19 to move axially towards the cam 7 to engage with the cam 7 so as to rotationally couple the cam 7 to the drive member 19) blocking member 23 will only engage one of the apertures 22 at a certain number of predefined rotational positions of the drive member 19 according to the number of apertures 22 provided. Here, six equispaced such apertures 22 are provided and so the drive member 19 needs to be rotated no more than 60 degrees before the blocking member 35 engages one of the apertures 22.

The engagement of blocking member 23 with aperture 22 also provides a stop such that the drive member 19 is restrained or prevented from moving axially away from the cam 7 when the blocking member 23 is in engagement with one of the apertures 22 such that the drive member 19 is held in non-disengageable engagement with the cam 7, thereby nondisengagably rotationally coupling the cam 7 to the drive member 19 and thereby to the internal side 5 of the body 4, thereby rotationally locking the cam 7 to the internal side 5 of the body 4 to prevent rotation of the cam 7 with respect to the internal side of the body 4. This is particularly advantageous as it prevents an attacker from disengaging the drive member 19 from rotational coupling with the cam 7 by simply pushing on the drive member 19 through the cam aperture 48 from the external side of the lock 1 once the sacrificial portion 31 has been removed during a snapping intrusion attack.

While the engagement of the blocking member 23 with aperture 22 prevents drive member 19 from moving axially away from the cam 7, the security mechanism also comprises a second blocking member 26 which is biased to protrude from, and into throughbore 63, its own radially-extending aperture 27 in the internal side 5 of the body 4 in order to provide additional capacity for resisting the drive member 19 being attempted to be pushed out of disengagement with the coupling 29 by an attacker by further preventing the drive member 19 from moving axially away from the cam 7. The first 23 and second 26 blocking members 22 are configured so as to simultaneously engage the drive member 19 at a predetermined axial position of the drive member 19 along the throughbore 63. At said predetermined axial position, blocking member 26 (here in the form of a pin 26, although other such suitable forms may be used instead), protrudes from aperture 27 so as to engage a stop 25 provided in the drive member 19. Here the stop 25 is provided as a circumferentially extending groove or lip 25 provided in the outer circumferential surface of the drive member 19, although other such suitable features may instead be used as a stop surface.

The external side 6 of the body 4 comprises a sacrificial portion 31, configured to snap and break away during a snapping intrusion attack at a predetermined area of weakness 32 defined by a breakaway slot 33 provided in the external side 6 of the body 4. A breakaway slot support 69 is provided in this example, but is not essential, and which sits in the breakaway slot 33 so as to prevent the sacrificial portion 31 becoming bent or damaged prior to installation.

The drive member 19 is biased indirectly against the sacrificial portion 31 by the biasing means 40 such that removal of the sacrificial portion 31 causes the drive member 19 to move axially towards the cam 7 such that the drive member 19 remains rotationally coupled to the coupling 28, and to a predetermined axial position within the throughbore 63 such that the first blocking member 23 is aligned with the plurality of circumferentially equispaced apertures 22 such that, when the drive member 19 is rotated (by forced rotation of the cam by an attacker), the first blocking member 23 is caused to protrude from its aperture 24 by its spring and into engagement with one of the apertures 22, holding the drive member 19 in non-disengageable engagement and non-disengageable rotational coupling with the coupling 28 which is itself held in non-disengageable engagement and non-disengageable rotational coupling with the cam 7, such that the drive member 19 is rotationally and axially locked to the cam 7. At this same predetermined axial position of the drive member 19, the second blocking member is released from its aperture 27 and engages stop 25 of the drive member 19 for further preventing the drive member 19 from moving axially away from the cam 7 and thereby becoming rotationally decoupled from the coupling 28.

The external clutch 42 comprises a base 46 and a sprung finger 47 biased apart from each other by external clutch spring 45. The external clutch 42 is slidlingly received within the external barrel 13 by way of a radially-projecting locking formations 43 provided on the external clutch 42 which ride along axially extending cutouts 77 provided in the internal end of the external barrel 13 so that the external clutch 42 is configured to slide axially away and toward the cam 7. Thus, the external clutch 42 is permanently rotationally coupled to the external barrel 13.

Locking formations 43 provided on the base 46, in this example in the form of diametrically opposed and radially extending lugs or wings 43 are configured to engage with corresponding locking formations (not shown) provided in the external side 37 of the cam 7 so that the cam 7 and external clutch 42 am rotationally coupled together when the locking formations 43 of the external clutch 42 are engaged with their corresponding locking formations on the cam 7.

The sprung-finger 47 comprises an axially extending projection 47. The cam aperture 48 is configured to receive this projection 47 such that the projection 47 is able to protrude sufficiently therethrough so as to be able to contact the projection 49 of the drive member 5 19 so as to be able to push the drive member 19 axially away from the cam 7 when a key is inserted into the external keyslot 14. As the biasing means 20 biases the thumbturn mechanism 17 out of engagement with the drive member 19, the thumbturn mechanism 17 is rotationally decoupled from the drive member 19 and therefore from the cam 7 and from the external barrel 13, allowing a key 95 placed in the external keyslot to rotate the cam but 10 not cause rotation of the thumbturn mechanism 17. A external barrel spacer 62 may also be provided as an optional feature, depending on the length of the external side 6 of the body 4.

Operation of the cylinder lock of the third embodiment will now be described with reference 15 to Figs 6A to 6J.

Figures 6A and 6B show the cylinder lock in the at rest position in which the thumbturn mechanism 17 is rotationally decoupled from the drive member 19 and in which a key 95 has not been inserted into the external keyslot 14. As with the second embodiment, the thumbturn mechanism 17 is rotationally decoupled from the drive member 19 by biasing means 40 which biases the locking formations 106 of the thumbturn mechanism 17 out of engagement with the corresponding locking formations 105 of the drive member 19. The biasing means 40 biases the drive member 19 into engagement with the coupling 28 such that the locking formations 38 on the drive member 19 are maintained in engagement with the corresponding locking formations 29 provided in an axially extending aperture 109 of the coupling 28 which extends from the internal face of the coupling 28. Thus, as the coupling 28 is rotationally coupled to the cam 7 by way of engagement of the coupling's cam locking formations 107 with their respective locking formations 30 provided in the cam 7, the cam 7 is rotationally coupled to drive member 19. The drive member 19 is rotationally decoupled from the internal side 5 of the body 4 as blocking member 23 remains recessed within its aperture 24 and does not engage with one of the circumferentially equispaced apertures 22 in the drive member 19. Thus, cam 7 is rotationally decoupled from the internal side 5 of the body 4.

As drive member 19 is biased by the biasing means 40, an axially extending projection 49 at the external end thereof, passes through the aperture of the coupling 28 and pushes directly on the end of the sprung finger 47, through the cam aperture 48 against the bias of external clutch spring 45 and, by way of the external clutch spring 45, the external clutch base 46 is biased axially away from the cam 7 such that the external clutch 42 is held out of locking engagement with the cam 7 such that the cam 7 is rotationally decoupled from the external clutch 42 and so thereby the cam 7 is rotationally decoupled from the external barrel 13 too. Nevertheless the external barrel 13 is prevented from rotation due to the external pin and tumbler arrangement 79 being misaligned with its shear plane. Although the external clutch base 46 is biased away from the sprung finger 75, they are only able to move a predetermined distance apart from each other and so the external clutch locking formations 43 provided on the base 46 are unable to engage the corresponding locking formations on external side 37 of the cam 7. Thus the cam 7 is not rotationally locked to either the internal 5 or external 6 sides of the body 4 in this configuration and is free to rotate, although the cam 7 is rotationally disengaged from both the thumbturn mechanism 17 as well as the external barrel 13.

The biasing means 40 biases the drive member 19 towards the cam such that the axially extending projection 49 of the drive member 19 pushes directly against the sprung finger 47 extending through the cam aperture 48, causing the sprung finger 47 to abut against the end of the external keyslot 14 (or packer 62 instead in embodiments in which packer 62 is present). Thus, the drive member 19 is unable to move any further in the external direction in this configuration. As such, the biasing means 40 now serves to bias the thumbturn mechanism 17 in the internal direction and away from the drive member 19 such that the thumbturn locking formations 106 are disengaged from the corresponding locking formations provided on the internal side of the drive member 19 such that the thumbturn mechanism 17 is rotationally decoupled with or disengaged from the drive member 19.

Thus, in this configuration, there is no load transfer path between the thumbturn mechanism 17 and the drive member 19 and so the drive member 19 can be rotated freely within the internal side 5 of the body 4 by knob 92. Thus, the thumbturn mechanism 17 is rotationally decoupled from the cam 7.

Also in this position of the drive member 19, the first blocking member 23 and second blocking member 26 are both depressed within their respective apertures 24, 27 by the outer circumferential surface of the drive member 19 being positioned over them, i.e. the first 23 and second 26 blocking members are not aligned with their respective aperture 24 and groove 25 respectively. Thus, the security mechanism, of which the first 23 and second 26 blocking members form a part of, is disengaged.

Turning now to Figures 6C and 6D, these figures show the configuration of the cylinder lock 1 of the third embodiment when the thumbturn mechanism 17 has been pushed axially by a user against the biasing force provided by the biasing means 40 towards the cam 7 such that the thumbturn mechanism locking formations 106 provided on the thumbturn shaft 18 engage the corresponding locking formations 105 provided on the drive member 19. Thus, the thumbturn mechanism 17 is now rotationally coupled to the drive member 19 such that rotation of the thumbturn mechanism 17 causes rotation of the drive member 19. Furthermore, as in the configuration of 6A, the axially extending projection of 21 of the thumbturn shaft 18 is slidingly received within an axially extending aperture 90 of the drive member 19. As the locking formations 38 on the axially extending projection 49 of the drive member 19 are still biased into locking engagement with the corresponding locking formations 29 provided on the coupling 28, the drive member 19 is rotationally coupled to the coupling 28. As the locking formations 107 on the coupling are in locking engagement with the corresponding locking formations 30 provided on the internal side of the cam 7, the coupling 28 is rotationally coupled to the cam 7. Thus, by engagement of the thumbturn mechanism 17 with the drive member 19 upon the thumbturn mechanism being moved axially towards the drive member 19, a rotational drive path is established between the thumbturn mechanism 17 and the cam 7, through drive member 19 and coupling 28, such that rotation of the thumbturn mechanism 17 causes rotation of the cam 7. Thus, the thumbturn mechanism 17 is operably connected to the cam 7.

The axially extending projection 49 of the drive member 19 remains biased directly against the sprung finger 47 of the external clutch 42, holding the external clutch 42 out of rotational coupling with the cam 7 (as the locking formations 43 of the external clutch 42 are held out of locking engagement with the corresponding locking formations [not shown] provided in the external side 37 of the cam 7). Thus, the drive member 19 is rotationally coupled to the cam 7 while at the same time the external clutch 42 is rotationally decoupled from the cam 7. Thus, it can be seen that the external clutch 42 is indirectly biased out of engagement with the cam 7 by the biasing means 40. Thus, the cam 7 is rotationally decoupled from the external barrel 13 and so is free to rotate upon rotation of the thumbturn mechanism 17.

As the drive member 19 is in the same axial position as that in Fig. 6A, the security mechanism remains undeployed -that is the first 23 and second 26 blocking members remain depressed within their respective apertures 24, 27 by the outer circumferential surface of the drive member 19 Figures 6E and 6F show the configuration of the cylinder lock 1 of the third embodiment when a key 95 is inserted into the external barrel key slot 14. The tip of the key 95 pushes against the external clutch 42, causing the external clutch 42 to move axially in the internal direction towards the cam 7 such that the sprung finger 47 protrudes further through cam aperture 48. The external clutch 42 is caused to move sufficiently towards the cam 7 that the locking formations 43 of the external clutch 42 engage with the corresponding locking formations (not shown) provided on the external side 37 of the cam 7 and thus the external clutch 42 becomes rotationally coupled to the cam 7.

As sprung finger 47 protrudes, or passes, further through cam aperture 48, the sprung finger 47 pushes directly against the axially extending projection 49 of the drive member 19 and causes the drive member 19 to move away from the cam 7 in the internal direction, against the biasing force provided by the biasing means 40. The locking formations 38 provided on the axially-extending projection 49 of the drive member 19 remain engaged with the corresponding locking formations 29 provided within the axially-extending aperture 109 of the coupling 28 (and the axially extending projection 49 remains slidingly received within the axially-extending aperture 109 of the coupling 28). Thus, the drive member 19 remains rotationally coupled with the cam 7 via coupling 28. The biasing means 40 biases the locking formations on the thumbturn mechanism 17 out of engagement with the internal clutch such that the thumbturn mechanism 17 is rotationally decoupled from the drive member 19 and therefore from the cam 7.

Insertion of the key 95 also causes the external pin and tumbler arrangement 79 to align with its shear plane such that the external barrel 13 becomes rotationally decoupled from the external side 6 of the body 4. Thus, insertion of the key 95 into the external keyslot 14 causes the external barrel 13 to become rotationally decoupled from the external side 6 of the body 4, and causes the external clutch to become rotationally coupled to the cam 7, while biasing means 40 maintains thumbturn mechanism 17 rotationally decoupled from the drive member 19 and therefore from the cam 7. Rotation of the key 95 causes the external barrel 13 to rotate, which causes the external clutch 42 to rotate, which then causes the cam 7 to rotate. Thus, insertion of the key 95 into the external keyslot 14 causes the external barrel 13 to become operatively connected to the cam 7 such that rotation of the external barrel via key 95 causes rotation of the cam 7. Thus a rotational drive path is establish between the external barrel 13 and the cam 7. The cam 7 can therefore be rotated between its first and second positions for actuating a locking means of the door by rotation of the key 95.

Figures 6G and 6H show the configuration of the cylinder lock 1 of the third embodiment when the sacrificial portion 31 of the external side 6 of the body 4 has been removed during a snapping intrusion attack from the external side of the lock 1. The sacrificial portion 31 has been snapped at the pre-weakened portion 32 provided by the breakaway slot 33 and has been removed by the attacker, along with the external clutch 42.

As the sprung finger 47 has in this configuration been removed during the attack, there is nothing stopping the biasing means 40 from pushing the drive member 19 further towards the coupling 28 and so the drive member 19 slides sufficiently towards the coupling 28 such that the first 23 and second 26 blocking members are uncovered by the drive member 19 such that simultaneously the first blocking member 23 is axially aligned with the plurality of circumferentially equispaced aperture 22 and the second blocking member 26 is aligned with the groove 25 such that the second blocking member 26 is released from its aperture 27 and engages the stop 25 provided in the drive member 19. Thus, the engagement of the second blocking member 26 with the stop 25 prevents the drive member 19 from being pushed out of locking engagement with the cam 7, for example from being pushed from the external side of the lock 1 in the internal direction and so the drive member 19 is in nondisengageable engagement with the cam 7, via coupling 38.

While the first blocking member 23 is axially aligned with the plurality of circumferentially equispaced apertures 22, depending of the rotational position of the drive member 19, the first blocking member 23 may or may not be rotationally aligned with one of the plurality of circumferentially equispaced apertures 22 and so, if the first blocking member 23 is misaligned with one of the plurality of circumferentially equispaced apertures 22, it remains depressed within its aperture 24 by the circumferential outer surface of the drive member 19. If the drive member 19 is rotationally aligned with one of the plurality of circumferentially equispaced apertures 22, the first blocking member 23 is released from its aperture and engages the one of the plurality of circumferentially equispaced apertures 22 it is aligned with such that the first blocking member 23 is received within the aperture 22. If the drive member 19 is not already rotationally aligned with one of the plurality of circumferentially equispaced apertures 22, it will become so as, not being able to remove cam 7 due to the attachment means 58 affixing the cam 7 to the coupling 28, the cam 7 is forcibly rotated by the attacker in attempting to actuate the door locking mechanism. Thus, first 23 and second 26 blocking members become engaged with the drive member 19 -the first blocking member 23 preventing both rotation of the cam 7 and also axial movement of the drive member 19; the second blocking member 26 preventing only axial movement of the drive member 19. Thus, as the drive member 19 remains rotationally coupled to the coupling 28 and as the coupling is rotationally coupled to the cam 7, the cam 7 is rotationally and axially locked with respect to the internal side 5 of the body 4 by engagement of blocking members 23 and 26 with apertures 22 and stop 25.

Removal of the cam 7 from the internal side 5 of the body 4 by the attacker is prevented by the attachment means 52 which securely axially affixes the cam 7 to the coupling 28 (but which does not rotationally couple the cam 7 to the coupling 28), the coupling 29 itself being securely axially affixed to the internal side 5 of the body 4 via the sliding engagement of pin 97 about circumferential groove 96 (Fig. 6B) which does not rotationally couple the coupling 28 to the internal side 5 of the body 4. The chamfered or rounded edge 8 of the cam 7 prevents the cam 7 from being gripped or grasped, for example by a clamping tool such as a pair of pliers, by an attacker for removal. Thus the cam 7 prevents access to the locking mechanism of the door which would otherwise be accessible if the cam 7 were able to be removed, thereby preventing the door from being opened.

As the drive member 19 has advanced further towards the cam 7 in this security configuration, releasing the second blocking member 26 and, depending on the rotational position of the drive member 19, also the first blocking member 23, the cam 7 has become non-disengageably rotationally coupled to the internal side 5 of the body 1. Thus, the cam 7 is prevented from rotation. Anti-drill pin 68 provided in the body 4 between the aperture 24 and the breakaway slot 33 prevents drilling from the external side to remove the first 23 or second 26 blocking member, or pin 97.

Figures 61 and 6J show the configuration of the cylinder lock 1 of the third embodiment when it is desired to unlock the door from the inside/interior of the room/building/space after a snapping intrusion attack. The thumbturn mechanism 17 is pressed in, towards the cam 7, causing the thumbturn shaft 18 to slide along throughbore 63 provided in the internal side 5 of the body 4 until circlip 88 engages an end face or shoulder of the circumferential groove 103 provided in the thumbturn shaft 18. In this position of the thumbturn mechanism 17, the locking formations 106 provided on the shaft 18 are in locking engagement with their respective locking formations 105 provided on the drive member 19 such that the thumbturn mechanism 17 is rotationally coupled to the drive member 19. The drive member 19 is in the same position as that shown in Figs 6G and 6H and so remains biased into engagement with, and rotationally coupled to, the coupling 28. Thus, the thumbturn mechanism 17 is rotationally coupled to the cam 7 such that there exists a rotational drive path between the thumbturn mechanism 17 and the cam 7. So that the drive member 19, and thereby the cam 7, may be rotated by the thumbturn mechanism 17, the axially-extending projection 49 of the shaft 18 comprises a chamfered or rounded edge 102 partway therealong, adjoining a first portion of the axially-extending projection 49 to a second portion of the axially-extending projection 49 which has a smaller diameter than the first portion, the second portion being arranged closer to drive member 19 than the first portion so as to form a ramped or inclined surface 102. Thus, when the thumbturn mechanism 17 is pressed into the lock (to the position shown in Fig. 61), each pin 90 arranged within each of the plurality of circumferentially equispaced apertures 22 rides along the ramped or inclined surface 102 so as to move radially outwards from the cam axis and to depress first blocking member 23 back into its aperture 24 against the biasing force provided by spring 66, thereby causing the first blocking member 23 to become disengaged from the one of the plurality of circumferentially equispaced apertures 22 it was previously in engagement with. Thus, the drive member 19 is now rotationally decoupled from the internal side 5 of the body 4 and rotation of the thumbturn mechanism 17 causes the cam 7 to be rotated so as to unlock the door.

The second blocking member 26 remains in engagement with the stop 25 provided on the drive member 19, however this is not problematic because, as the sacrificial portion 31 of the lock 1 has been removed (and the external barrel 13 and external clutch 42 therewith), the cylinder lock has been irreparably damaged and will be replaced by the user.

Various modifications may be made to the embodiments described without departing from the scope of the invention as defined by the accompanying claims.

Claims

CLAIMS1. A cylinder lock for a door having an internal side and an external side, the cylinder lock comprising: a body having an internal side configured to be arranged on the internal side of the door when the cylinder lock is installed in the door; and the body also having an external side configured to be arranged on the external side of the door when the cylinder lock is installed in the door; a cam for actuating a locking means of the door, the cam being arranged between the internal side of the body and the external side of the body; and wherein the cam comprises a peripherally extending rounded or chamfered edge on an outer circumferential surface of the cam, the rounded or chamfered edge facing towards the external side of the body of the cylinder lock.
2. The cylinder lock of Claim 1, wherein the internal side of the body comprises an internal lock actuator configured so as to be actuatable from the internal side of the door when the cylinder lock is installed in the door.
3. The cylinder lock of Claim 1 or Claim 2, wherein the external side of the body comprises an external lock actuator configured so as to be actuatable from the external side of the door when the cylinder lock is installed in the door.
4. The cylinder lock of Claim 2 or 3, wherein the internal lock actuator is rotatably received within the internal side of the body of the cylinder lock and/or the external lock actuator is rotatably received within the external side of the body of the cylinder lock.
5. The cylinder lock of any one of Claims 1 to 4, wherein the cam comprises an external end and an internal end corresponding to the external side and internal side of body of the 30 cylinder lock respectively, and wherein the peripherally extending chamfered or rounded edge is provided at or towards the external end of the cam.
6. The cylinder lock of any one of Claims 2 to 5, wherein the internal lock actuator and/or the external lock actuator are selectively rotationally couplable and decouplable with 35 the cam.
7. The cylinder lock of any one of Claims 3 to 6 when dependent on Claim 2, wherein the cylinder lock is configured such that, when the external lock actuator is rotationally coupled with the cam, the internal lock actuator is rotationally decoupled from the cam.
8. The cylinder lock of any one of Claims 3 to 7, wherein the external lock actuator comprises an external barrel rotatably received within the external side of the body.
9. The cylinder lock of Claim 8, wherein the external barrel comprises an external key slot which is configured to actuate the external lock actuator.
10. The cylinder lock of any one of Claims 2 to 9 when dependent on Claim 2, wherein the internal lock actuator comprises an internal barrel rotatably-received within the internal side of the body.
11. The cylinder lock of any one of Claims 2 to 10 when dependent on Claim 2, wherein the internal lock actuator comprises an internal key slot which is configured to actuate the internal lock actuator.
12. The cylinder lock of any preceding claim, wherein the external side of the body 20 comprises a breakaway-slot for forming a predetermined area of weakness such that a snapping intrusion attempt causes the body to snap at the predetermined area of weakness.
13. The cylinder lock of any preceding claim, wherein the cam is configured to rotate about a cam axis between a first rotational position corresponding to a locked configuration 25 of the door and a second rotational position corresponding to an unlocked configuration of the door.
14. The cylinder lock of Claim 13 when dependent on Claim 2, wherein the cylinder lock comprises a drive member configured to provide a rotational drive path between the internal 30 lock actuator and the cam to rotate the cam between the first and second rotational positions thereof.
15. The cylinder lock of Claim 14, wherein the drive member is an internal clutch configured to selectively form a rotational drive path between the internal lock actuator and 35 the cam to rotate the cam between the first and second rotational positions thereof.
16. The cylinder lock of Claim 15, wherein the internal clutch has an internal-clutch-engaged configuration in which the internal clutch is rotationally coupled with the cam, and an internal-clutch-disengaged configuration in which the internal clutch is rotationally decoupled from the cam; wherein the cylinder lock is selectively configurable between the internal-clutch engaged configuration and the internal-clutch disengaged configuration.
17. The cylinder lock of Claim 15 or Claim 16, wherein the cam has an internal side arranged towards the internal side of the body, and wherein the internal clutch comprises one or more internal-clutch locking formations configured to engage with corresponding 10 locking formations provided in the internal side of the cam.
18. The cylinder lock of any one of Claims 16 or 17, wherein the internal clutch is rotationally coupled or couplable to the internal lock actuator such that, when the internal clutch is in the internal-clutch-engaged configuration, rotation of the internal lock actuator 15 causes rotation of the cam.
19. The cylinder lock of any one of Claims 16 to 18, wherein the cylinder lock comprises biasing means arranged to provide a biasing force to bias the internal clutch into the internalclutch-engaged configuration.
20. The cylinder lock of Claim 19, wherein the biasing means comprises a spring or bias arranged within the internal side of the cylinder body.
21. The cylinder lock of any one of Claim 3 to 20, wherein the cylinder lock further comprises an external clutch configured to selectively form a rotational drive path between the external lock actuator and the cam to lock and unlock the locking means of the door.
22. The cylinder lock of Claim 21, wherein the cylinder lock has an external-clutch-engaged configuration in which the external clutch is rotationally coupled to the cam, and an external-clutch-disengaged configuration in which the external clutch is rotationally decoupled from the cam; wherein the cylinder lock is selectively configurable between the external-clutch-engaged configuration and the external-clutch-disengaged configuration.
23. The cylinder lock of Claim 22 when dependent on Claim 8, wherein the external barrel comprises an external key slot and wherein insertion of a key into the external key slot causes the cylinder lock to adopt the external-clutch engaged configuration.
24. The cylinder lock of Claim 23, wherein the cylinder lock is configured such that insertion of a key into the external key slot causes the external clutch to be pushed into engagement with the cam such that the external clutch becomes rotationally coupled with the cam.S
25. The cylinder lock any one of Claims 21 to 24 when dependent on Claim 19, wherein the biasing means is configured to indirectly bias the external clutch out of engagement with the cam.
26. The cylinder lock of any one of Claims 23 to 25, wherein the cylinder lock is configured such that removal of the key from the external key slot causes the cylinder lock to adopt the external-clutch-disengaged configuration.
27. The cylinder lock of any one of Claims 21 to 26, wherein the cam has an external 15 side arranged towards the external side of the body, wherein the external clutch comprises one or more external-clutch locking formations configured to engage with corresponding locking formations provided in the external side of the cam.
28. The cylinder lock of any one of Claims 22 to 27 when dependent on Claim 8, wherein 20 the external clutch is rotationally coupled to the external barrel such that, when the external clutch is in the external-clutch-engaged configuration, rotation of the external barrel causes rotation of the cam.
29. The cylinder lock of any one of Claims 22 to 28 when dependent on Claim 16, 25 wherein the cylinder lock is configured such that, when the cylinder lock is in the externalclutch-engaged configuration, the cylinder lock is also in the internal-clutch-disengaged configuration.
30. The cylinder lock of any one of Claims 22 to 29 when dependent on Claim 16, 30 wherein the cylinder lock is configured such that, when the cylinder lock is in the internalclutch-engaged configuration, the cylinder lock is also in the external-clutch-disengaged configuration.
31. The cylinder lock of any one of Claims 21 to 30, wherein the external clutch is biased 35 out of locking engagement with the cam.
32. The cylinder lock of any one of Claims 21 to 31, wherein the external clutch comprises a base, an external clutch spring and an axially-extending sprung-finger biased by the external clutch spring.
33. The cylinder lock of Claim 32, wherein the external clutch spring is configured to bias the sprung-finger away from the base.
34. The cylinder lock of Claim 32 or 33, wherein the external clutch spring biases the sprung-finger into engagement with the cam
35. The cylinder lock of any preceding claim, wherein the cam has an aperture extending axially therethrough.
36. The cylinder lock of Claim 35 when dependent on Claims 15, 22 and 32, wherein the aperture of the cam is configured to receive the sprung-finger of the external clutch such that when the external clutch is in the external-clutch-engaged configuration, the internal clutch is held out of rotational coupling with the cam by the sprung finger of the external clutch.
37. The cylinder lock of Claim 35 or 36 when dependent on Claims 16 and 22, wherein the aperture of the cam is configured to receive an axially-extending projection of the internal clutch such that, when the internal clutch is in the internal-clutch-engaged configuration, the external clutch is held out of engagement with the cam by the axially-extending projection of the internal clutch.
38. The cylinder lock of any one of Claims 35 to 37, wherein the axially-extending projection of the internal clutch protrudes into the axially-extending aperture of the cam when the cylinder lock is in the internal-clutch-engaged configuration such that the external clutch is caused to become rotationally decoupled from the cam.
39. The cylinder lock of Claim 37 or 38, wherein the cylinder lock is configured such that the external clutch is caused to become rotationally decoupled from the cam by the axially-extending projection of the internal clutch acting on, e.g. pushing against, the external clutch thereby moving the external clutch out of engagement with the cam when a key is inserted into a key slot of the internal barrel.
40. The cylinder lock of any one of Claims 37 to 39, wherein the cylinder lock is configured such that, when the axially extending projection of the internal clutch protrudes into the axially-extending aperture of the cam, the external clutch is caused to move out of engagement with the cam against the biasing force biasing the external clutch into the external-clutch-engaged configuration.
41. The cylinder lock of any one of Claims 35 to 40 when dependent on Claim 15,22 and Claim 32, wherein, when the cylinder lock is in the external-clutch-engaged configuration, the sprung-finger protrudes into the axially-extending aperture of the cam 10 such that the internal clutch is caused to become rotationally decoupled from the cam.
42. The cylinder lock of any one of Claims 32 to 41 when dependent on Claim 15, wherein the internal clutch is caused to become rotationally decoupled from the cam by the sprung-finger of the external clutch acting on, e.g. pushing against, the internal clutch 15 thereby moving the internal clutch out of locking engagement with the cam.
43. The cylinder lock of any one of Claims 33 to 42 when dependent on Claim 15, wherein the cylinder lock is configured such that, when a key is inserted into a key slot of the external barrel, the sprung-finger of the external clutch acts on, e.g. pushes against, the internal clutch thereby moving the internal clutch out of engagement with the cam and thereby causing the internal clutch to become rotationally decoupled from the cam.
44. The cylinder lock of any one of Claims 15 to 43, wherein the cylinder lock comprises a security configuration in which the internal clutch is non-disengagably engaged with the cam so as to prevent rotation of the cam, the cylinder lock further comprising a security mechanism configured to maintain the cylinder lock in the security configuration upon removal of a sacrificial portion of the external side of the body.
45. The cylinder lock of Claim 44, wherein, the internal clutch comprises a stop and wherein the security mechanism comprises a blocking member arranged in, and biased to protrude from, an aperture provided in the internal side of the body, such that the internal clutch is restrained from axial movement when the blocking member protrudes from the aperture and engages the stop of the internal clutch.
46. The cylinder lock of Claim 44 or 45, wherein the external side of the body comprises a pre-weakened portion of the body to define the sacrificial portion.
47. The cylinder lock of any one of Claims 2 to 46 when dependent on Claim 2, wherein the internal lock actuator comprises a thumb-turn mechanism configured to actuate the internal lock actuator from the internal side of the door.
48. The cylinder lock of Claim 47 when dependent on Claim 15, wherein the thumb-turn mechanism comprises a shaft rotatable by a user, the shaft being slidably received by, and rotatable within, the internal side of the body, the drive member being slidably received by, and rotatably received within, the internal side of the body, the shaft comprising biasing means configured to bias the drive member axially towards the cam.
49. The cylinder lock of Claim 48, wherein the shaft comprises an axially extending projection which is configured to be slidably received by the drive member.
50. The cylinder lock of Claim 48 or Claim 49 when dependent on Claim 15, wherein the drive member comprises at least one radially extending aperture or recess configured to receive a first blocking member arranged in, and biased to protrude from, a first aperture provided in the internal side of the body, such that the drive member is rotationally locked to the internal side of the body when the first blocking member is received by one of the at least one radially extending apertures.
51. The cylinder lock of Claim 50, wherein the drive member comprises a plurality of radially extending and angularly-eguispaced apertures, each being configured to receive the first blocking member arranged in, and biased to protrude from, the first aperture provided in the internal side of the body.
52. The cylinder lock of Claim 50 or 51, wherein the drive member comprises a stop and the internal side of the body comprises a second blocking member arranged in, and biased to protrude from, a second aperture provided in the internal side of the body, the second blocking member being configured to engage the stop of the drive member so as to prevent axial movement of the drive member in at least one axial direction when the second blocking member is in engagement with the stop.
53. The cylinder lock of any one of Claims 47 to 52 when dependent on Claim 15, wherein the internal clutch is selectively rotationally couplable to a coupling element, the coupling element being rotationally coupled to the cam such that rotation of the internal clutch causes rotation of the cam when the internal clutch is rotationally coupled to the coupling element.
54. The cylinder lock of Claim 53, wherein the coupling element is non-disengageably rotationally coupled to the cam.
55. The cylinder lock of Claim 53 or Claim 54, wherein axial movement of the internal clutch towards the coupling element causes the internal clutch to rotationally couple with the coupling element, and wherein axial movement of the internal clutch away from the coupling element causes the internal clutch to rotationally decouple from the coupling element.
56. The cylinder lock of any one of Claims 54 to 55, further comprising a biasing means configured to bias the internal clutch into engagement with the coupling element.
57. The cylinder lock of any one of Claims 53 to 56, wherein the rotational coupling of 15 the internal clutch and the coupling element is provided by corresponding locking formations provided on the internal clutch and the coupling element.
58. The cylinder lock of any one of Claims 53 to 57, wherein the coupling element is rotationally coupled to the cam by corresponding locking formations provided on the 20 coupling element and the cam.
59. The cylinder lock of any one of Claims 52 to 58, wherein the cylinder lock is configured such that removal of a sacrificial portion of the external side of the body causes the drive member to non-disengagably rotationally couple with the coupling element, and the drive member to become rotationally coupled to the internal side of the body such that the cam becomes rotationally locked with respect to the body.
60. The cylinder lock of any one of Claims 53 to 58, wherein the cylinder lock is configured such that removal of a sacrificial portion of the external side of the body causes the internal clutch to non-disengagably rotationally couple with the coupling element, the internal clutch being rotationally coupled to the body, such that the cam becomes rotationally locked with respect to the body.
61. The cylinder lock of Claim 59, wherein the drive member is biased indirectly against 35 the sacrificial portion such that removal of the sacrificial portion causes the drive member to non-disengagably rotationally couple with the cam, thereby rotationally locking the cam to the internal side of the body of the cylinder lock.
62. The cylinder lock of Claim 60, wherein the internal clutch is biased indirectly against the sacrificial portion such that removal of the sacrificial portion causes the internal clutch to non-disengagably rotationally couple with the coupling element, thereby rotationally 5 locking the cam to the internal side of the body of the cylinder lock.
63. The cylinder lock of any one of Claims 59 to 62, wherein the external side of the body comprises a pre-weakened portion of the body to define the sacrificial portion.
64. The cylinder lock of any preceding claim, wherein the cam is configured to rotate, for actuating a locking mechanism of the door, about a cam axis between a first rotational position thereof corresponding to a locked configuration of the door and a second rotational position thereof corresponding to an unlocked configuration of the door.
65. The cylinder lock of Claim 64, wherein the cam comprises a radially extending lug for actuating a locking mechanism of the door upon rotation of the cam.
66. The cylinder lock of any preceding claim, wherein the chamfered edge has a chamfer angle of between about 1 degrees and 89 degrees relative to a longitudinal axis of the cylinder lock (or the rotational axis of the cam), optionally about, or a range defined by any combination of, 1, 10, 20, 30, 40, 45, 50, 55, 60, 65, 70, 80 degrees or any intermediate value between 1 and 89 degrees or any combination thereof.
67. The cylinder lock of any preceding claim, wherein the cam is affixed to the internal 25 side of the body by an attachment means so as to inhibit removal of the cam from the cylinder lock orthe internal side of the body, e.g. during an intrusion attack from the external side of the door.
68. The cylinder lock of Claim 67, wherein the cam is prevented from axial movement, 30 in at least one axial direction, relative to the internal side of the body by the attachment means, optionally wherein the cam is prevented from moving axially away from the internal side of the body by the attachment means.
69. The cylinder lock of Claim 67 or Claim 68, wherein the attachment means is 35 configured to affix the cam to a coupling element provided within the internal side of the body, the coupling element being axially restrained with respect to (e.g. axially locked to or affixed to) the internal side of the body and therefore prevented from moving axially, in at least one axial direction, relative to the internal side of the body, or being removed from the internal side of the body, optionally the coupling element is prevented from moving axially away from the internal side of the body.
70. The cylinder lock of any one of Claims 67 to 69 when dependent on Claim 10, wherein the cam is affixed to the internal barrel, e.g. to an end portion of the internal barrel, by the attachment means and the internal barrel is affixed to the internal side of the body, such that the cam is indirectly affixed to the internal side of the body by the attachment means via the internal barrel.
71. The cylinder lock of Claim 67 to 70 when dependent on Claim 10, wherein the cam is prevented from axial movement relative to the internal barrel by the attachment means, and optionally wherein the attachment means does not rotationally couple the cam to the internal barrel.
72. The cylinder lock of any one of Claims 67 to 71, wherein the cam comprises a recess or circumferential groove for receiving the attachment means.
73. The cylinder lock of Claim 72, wherein the cam is configured so as to cover at least a portion of the recess or circumferential groove and/or attachment means when attached to the internal barrel such that external access to the attachment means in at least one rotational position of the cam is prevented.
74. The cylinder lock of Claim 72 or 73, wherein the recess or circumferential groove is arranged on an inner surface of the cam, e.g. optionally the recess or circumferential groove is provided in an inner annular circumferential surface of the cam, so as to be externally inaccessible.
75. The cylinder lock of any one of Claims 67 to Claim 74 when dependent on Claim 10, wherein the internal barrel comprises a recess or circumferential groove for receiving the attachment means for affixing the cam to the internal barrel.
76. The cylinder lock of Claim 75, wherein the recess or circumferential groove of the internal barrel is arranged on an outer surface of the internal barrel.
77. The cylinder lock of Claim 69 to Claim 76, wherein the coupling element comprises a recess or circumferential groove for receiving the attachment means for affixing the cam to the internal side of the body.
78. The cylinder lock of Claim 77, wherein the recess or circumferential groove of the coupling element is arranged on an outer surface of the coupling element.
79. The cylinder lock of any one of Claims 67 to 78, wherein the cam comprises an access window for providing access to the attachment means for removing or installing the 10 attachment means
80. The cylinder lock of any one of Claims 67 to 79, wherein the attachment means is a snap ring.
81. The cylinder lock of Claim 80 when dependent on Claim 10, wherein the snap ring is provided within a circumferential groove provided in an inner surface of the cam and a corresponding circumferential groove provided in an outer surface of the internal barrel.
82. The cylinder lock of Claim 80 when dependent on Claim 77 or 78, wherein the snap 20 ring is provided within a circumferential groove provided in an inner surface of the cam and a corresponding circumferential groove provided in an outer surface of the coupling element.
83. A cam for a cylinder lock having an externally-accessible side and an internally accessible side opposite the externally-accessible side, the externally-accessible side being accessible from the external side of a door when the cylinder lock is installed in a door and the internally-accessible side being accessible from the internal side of a door when the cylinder lock is installed in a door, the cam comprising: a peripherally extending rounded or chamfered edge on an outer circumferential 30 surface of the cam; wherein the cam is configured such that, when installed in the cylinder lock, the rounded or chamfered edge faces towards the externally-accessible side of the cylinder lock.
84. The cam of Claim 83, wherein the cam comprises an external end at a first end of the cam and an internal end at a second end of the cam, opposed to the first end, the external end and internal end corresponding to the externally-accessible side and the internally-accessible side of the cylinder lock respectively, and wherein the peripherally extending chamfered or rounded edge is provided at or towards the external end of the cam.
85. The cam of Claim 83 or 84, wherein the chamfered edge has a chamfer angle of between about 1 degrees and 89 degrees relative to a longitudinal axis of the cylinder lock or cam or the rotational axis of the cam, optionally about, or a range defined by any combination of, 10, 20, 30, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85 degrees or any intermediate value between 1 and 89 degrees or combination thereof
86. The cam of any one of Claims 83 to 85, wherein the chamfered or rounded edge protrudes axially from the external end of the cam.
87. A cylinder lock for a door having an internal side and an external side, the cylinder lock comprising: a body having an internal side configured to be arranged on the internal side of the door when the cylinder lock is installed in the door; and the body also having an external side configured to be arranged on the external side of the door when the cylinder lock is installed in the door; a cam for actuating a locking means of the door, the cam being arranged between the internal side of the body and the external side of the body; and wherein the cam is affixed to the internal side of the body by an attachment means so as to inhibit removal of the cam from the cylinder lock or internal side of the body, e.g. during an intrusion attack from the external side of the door.
88. The cylinder lock of Claim 87, wherein the cam is configured to rotate, for actuating a locking mechanism of the door, about a cam axis between a first rotational position corresponding to an unlocked configuration of the door and second rotational position corresponding to a locked configuration of the door.
89. The cylinder lock of any one of Claims 87 or 88, wherein the cam is prevented from axial movement, in at least one axial direction, relative to the internal side of the body by the attachment means, optionally wherein the cam is prevented from moving axially away from the internal side of the body by the attachment means.
90. The cylinder lock of any one of Claims 87 to 89, wherein the attachment means is configured to affix the cam to a coupling element provided within the internal side of the body, the coupling element being axially restrained with respect to (e.g. axially locked to) the internal side of the body and therefore prevented from moving axially, in at least one axial direction, relative to the internal side of the body, optionally the coupling element is prevented from being removed from the internal side of the body.S
91. The cylinder lock of Claim 90, wherein the coupling element is provided within a longitudinally extending through-bore provided in the internal side of the body.
92. The cylinder lock of any one of Claims 87 to 91, wherein the cam is affixed to a barrel rotatably received within a longitudinally extending through-bore provided in the internal side of the cylinder body, e.g. to an end portion of the internal barrel, by the attachment means and optionally the barrel is affixed to the internal side of the body such that the cam is indirectly affixed to the internal side of the body by the attachment means via the barrel.
93. The cylinder lock of Claim 92, wherein the cam is prevented from axial movement relative to the barrel by the attachment means, and optionally wherein the attachment means does not rotationally couple the cam to the internal barrel.
94. The cylinder lock of any one of Claims 87 to 93, wherein the cam comprises a recess or circumferential groove for receiving the attachment means.
95. The cylinder lock of any one of Claims 87 to 94, wherein the cam covers at least a portion of, or optionally the entirety of, the recess or circumferential groove and/or attachment means when the cam is attached to the internal barrel such that external access to the attachment means in at least one rotational position of, optionally in all rotational positions of, the cam is prevented.
96. The cylinder lock of any one of Claims 87 to 95, wherein the recess or circumferential 30 groove is arranged on an inner surface of the cam, e.g. optionally the recess or circumferential groove is provided in an inner annular circumferential surface of the cam, so as to inhibit external access to at least a portion of the circumferential groove.
97. The cylinder lock of any one of Claims 92 to 96, wherein the barrel comprises a 35 recess or circumferential groove for receiving the attachment means for affixing the cam to the barrel.
98. The cylinder lock of Claim 97, wherein the recess or circumferential groove of the barrel is arranged on an outer circumferential surface of the barrel.
99. The cylinder lock of any one of Claims 90 to 98, wherein the coupling element comprises a recess or circumferential groove for receiving the attachment means for affixing the cam to the internal side of the body.
100. The cylinder lock of Claim 99, wherein the recess or circumferential groove of the coupling element is arranged on an outer circumferential surface of the coupling element.
101. The cylinder lock of any one of Claims 87 to 100, wherein the cam comprises an access window or cut-out for providing access to the attachment means for removing or installing the attachment means.
102. The cylinder lock of any one of Claims 87 to 101, wherein the attachment means is a snap ring.
103. A method of manufacturing the cylinder lock of Claim 1.
104. A method of manufacturing the cam of Claim 83.
105. A method of manufacturing the cylinder lock of Claim 87.