Patent Description:
Most external doors in buildings comprise a door lock for improved security. A particular form of lock is the Euro cylinder lock, this comprising a cylinder lock actuator which has a moveable cam for interacting with the locking mechanism held within the door. Euro cylinder locks provide a particular standard of door locks and have a well-known footprint for interacting with a cylinder lock actuator, thus allowing for a door to be produced with an integral locking mechanism and a separate cylinder lock actuator integrated therewith. Cylinder lock actuators are well-known in the art, and typically provide at least one lock cylinder which controls the rotation of a cam. The cam is provided with a lug which will interact with the lock in the door, when the cylinder lock actuator is held therein, such that rotation of the cam leads to the lock being transferred from a locked to unlocked state, and vice versa. The lock cylinder is mechanically connectable to the cam, such that rotation of the lock cylinder leads to rotation of the cam as desired. The lock cylinder can be a traditional key-operated lock cylinder, comprising spring loaded pins which when the correct key is inserted therein will align and allow rotation of the lock cylinder and subsequent rotation of the cam. Similar lock cylinders are known and may comprise a thumb turn lock, wherein the thumb turn will also mechanically engage with the cam to lock and unlock the lock.

Most cylinder lock actuators comprise two lock cylinders either side of the central cam held there-between in a rotatable manner. A first of the lock cylinders is to be positioned on the inside of the door in use, a second of the lock cylinders is positioned outside or on the exterior side of the door when in use. In such situations, the interior lock may be provided by the thumb turn disclosed above, or may be a key operated lock cylinder requiring the use of the correct key to allow rotation thereof. Usually, the exterior lock cylinder will be a key operated lock cylinder to increase security, wherein this exterior lock cylinder is open to vandalism and attack by burglars trying to unlawfully gain entry to the lock and to unlock the door and gain entry to the building.

It is known in the art, for example: as shown in <CIT>, to incorporate a specific weakness to the exterior lock cylinder, the weakness being located such that the exterior lock cylinder will readily snap off from the cylinder lock actuator to leave the cam within the lock of the door and the interior lock cylinder in place. Additionally, <CIT> discloses a safety device for lock cylinders formed of inner and outer stators. Whereby, upon the removal of an outer stator the cam may be locked axially and radially. Further mechanisms are also presented which then lead to the cam being mechanically connected to the interior lock cylinder, such that the cam can only be rotated by means of the interior lock cylinder. Indeed, it is a regulatory requirement for cylinder lock actuators that, after vandalism, a user on the inside of the door is fully able to actuate the lock and not get locked in. Evidently, if the exterior lock cylinder has been removed and the cam exposed within the lock housing, it is undesirable for the cam to be rotatable from the exterior side of the door. Numerous different techniques may be employed for locking the cam to the interior lock cylinder, each of these only allowing rotation of the cam by means of rotating the interior lock cylinder.

Once the exterior lock cylinder has been removed, the interior side of the cylinder lock actuator, and in particular the mechanical components held within the cam, can often be attacked by a burglar and may lead to a reduction in security and even actuation of the cam by the burglar. Any mechanism to reduce the effectiveness of the burglar who has gained access to the interior of the cam in operating said cam, leads to further time being spent by the burglar and a greater chance that the burglar is disturbed before gaining entrance to the building. It is further desirable to reduce the components of the cylinder lock actuator which can be accessed by the burglar after vandalism and removal of the exterior lock cylinder, thus further thwarting attempts to unlock the lock. Finally, allowing the burglar access to the interior of the cam, wherein elements have been left within the cam which make further access to the lock cylinder difficult, can again cause the burglar to spend more time and will thus improve the security of the lock in general.

The abovementioned aims are met by the cylinder lock actuator of the present invention. The present invention relates to a cylinder lock actuator which has improved security features ensuring that the cam remains properly fixed to the interior lock cylinder after vandalism and removal of the exterior lock cylinder, whilst also ensuring that the burglar has limited access to parts of the cylinder lock actuator which are mechanically interconnecting the cam with the first lock cylinder. The cylinder lock actuator further comprises elements which are held within the cam and which, upon vandalism of the lock and removal of the exterior lock actuator may remain and thereby provide obstructions to the burglar in attempting to gain further access to the inner elements of the cylinder lock actuator. In any event, any elements remaining in the cylinder lock actuator <NUM> can take no further part in operation of the cylinder lock actuator <NUM>.

The above, and other, problems are addressed by the present invention which is directed to a cylinder lock actuator comprising a first lock cylinder, a second lock cylinder and a clutch mechanism, the clutch mechanism being adapted to selectively engage either the first lock cylinder or the second lock cylinder with a cam held rotatably in the cylinder lock actuator, wherein the cam is held in an axially moveable manner within the cylinder lock actuator, the cam being normally located in a first axial position within the cylinder lock actuator such that the clutch mechanism can engage either of the first lock cylinder or second lock cylinder therewith, the cylinder lock actuator further comprising biasing means which is adapted to axially move the cam into a second position upon removal of the second lock cylinder, the cylinder lock actuator comprising locking means which is adapted to constrain the cam with respect to the first lock cylinder when the cam is in the second position, and the biasing means and locking means are adapted to operate independently of the state of the clutch.

The present invention is directed to a mechanism of fixing rotation of the cam of the cylinder lock actuator after vandalism, thus ensuring that it cannot be rotated by a burglar from the exterior of the door but remains fully operable by a user on the inside. The cylinder lock actuator of the invention also provides increased security by isolating the means of securing the cam post-vandalism from the normal functioning of the cam in the cylinder lock actuator prior to vandalism.

In the following description, the cylinder lock actuator <NUM> is shown comprising a thumb turn <NUM> as the interior actuation mechanism and a key <NUM> as the exterior actuation mechanism. This is explicitly by way of example only. The skilled reader will fully understand that the interior side of the cylinder lock actuator <NUM> may also be operated by means of a key <NUM>, and the use of the thumb turn <NUM> is purely exemplary. In the following, specific elements which are shown of the thumb turn <NUM> and the interior lock cylinder <NUM> as integrating with the thumb turn <NUM> are not disclosed. The drawings relate to the co-pending application: <CIT>, which is held by the same Applicant. The interaction between the thumb turn <NUM> and the interior lock cylinder <NUM>, also known as the first lock cylinder <NUM>, are not decisive for the operation of the current lock; it will be appreciated they could be achieved by any known thumb turn operator or key operated lock cylinder. <FIG> shows the general form of the cylinder lock actuator <NUM>. The cylinder lock actuator <NUM> comprises the first or interior lock cylinder <NUM>, which is provided on the left hand side of <FIG> and is operated by the thumb turn <NUM>. The second or <FIG> shows the general form of the cylinder lock actuator <NUM>. The cylinder lock actuator <NUM> comprises the first or interior lock cylinder <NUM>, which is provided on the left hand side of <FIG> and is operated by the thumb turn <NUM>. The second or exterior lock cylinder <NUM> is provided on the right hand side in the figure and is intended to be located on the exterior side of the door and is operated by means of the key <NUM>. The cam <NUM> comprising the lug <NUM> for operating the lock to move this between the locked and unlocked orientations within the door, is held in a rotatable manner between the interior lock cylinder <NUM> and the exterior lock cylinder <NUM>. It will be noted that the lug <NUM> fits within a lug gap <NUM> of the housing <NUM> of the cylinder lock actuator <NUM>. The housing <NUM> surrounds the interior lock cylinder <NUM> and exterior lock cylinder <NUM>, housing these in the cylinder lock actuator <NUM>. The lug gap <NUM> consequently allows for the lug <NUM> to pass through the housing <NUM> in order to open and close the lock as required. The housing <NUM> comprises a weakness <NUM>, typically and as shown in the figures in the form of a slot through the housing <NUM> in the region of the most exterior end of the cam <NUM>. The weakness <NUM> is so located that upon vandalism of the cylinder lock actuator <NUM>, the entire exterior lock cylinder <NUM> and the part of the housing <NUM> housing the exterior lock cylinder <NUM> will be snapped off and removed from the cylinder lock actuator <NUM>. The perspective view shown in <FIG> of the cylinder lock actuator <NUM> shows one possible state of the cylinder lock actuator <NUM> after it has been vandalised; the manner in which elements within the cam <NUM> are affected by vandalism is quasi-random, so it is not guaranteed what parts will remain within the cam <NUM>. As will be seen in the cut-away images of <FIG>, <FIG> and <FIG>, the region of the housing <NUM> surrounding the lug gap <NUM> can further comprise a strengthening block which provides improved rigidity to this part of the housing <NUM>. Such blocks are known in the art and no further description need be made in this disclosure.

Turning attention to the cut-away view of <FIG>, the cylinder lock actuator <NUM> and the operation thereof can be seen in more detail. The key <NUM> is shown inserted within the keyway of the exterior lock cylinder <NUM>, such that the spring-loaded split pins are appropriately aligned and the exterior cylinder lock actuator <NUM> could be rotated by rotating the key <NUM>. This exterior lock cylinder <NUM> operates in a known manner and the operation of the spring-loaded split pins is well-known and is not further discussed herein. As further mentioned above, the interior lock cylinder <NUM> comprising the thumb turn <NUM> as shown in <FIG> is a specific thumb turn <NUM> operating for the interior lock cylinder <NUM>. The specific operation allowing the thumb turn <NUM> to take over control of the interior lock cylinder <NUM> such that rotation of the thumb turn <NUM> is translated into rotation of the interior lock cylinder <NUM> is described elsewhere, in particular co-pending application <CIT>. This particular interaction is not germane for the specific features of the present invention, and need not be discussed further. As further mentioned, the particular locking mechanism used for the interior lock cylinder <NUM> to either stop or allow rotation of the interior lock cylinder <NUM> within the housing <NUM> is not relevant, the use, therefore, of any known lock cylinder is explicitly included in this disclosure. The present disclosure will explain in further detail the differences in the structure of the interior lock cylinder <NUM> making up the present invention.

As shown in <FIG>, the cam <NUM> is generally cylindrical in nature and comprises an axial bore <NUM> along its entire length. The axial bore <NUM> extends from the interior end of the cam <NUM> to the exterior end of the cam <NUM>, as viewed when in the door, and comprises a clutch mechanism <NUM> therein. The clutch mechanism <NUM> is configured so as to allow preferential control of rotation of the cam <NUM> by the interior lock cylinder <NUM> or the exterior lock cylinder <NUM>. The clutch mechanism <NUM> provides means for either of the interior lock cylinder <NUM> or the exterior lock cylinder <NUM> to take control over the cam <NUM>, such that rotation of the relevant lock cylinder leads to rotation of the cam <NUM> to lock and unlock the lock. As shown in <FIG>, the clutch mechanism <NUM> may further comprise a torsion ring <NUM> which is a generally circular, ring-like item positioned within the axial bore <NUM> of the cam <NUM>. The torsion ring <NUM> is so configured that it is within the cylinder lock actuator <NUM> prior to it being vandalised, in such a state that rotation of the torsion ring <NUM> will lead to rotation of the cam <NUM>. This first state of the torsion ring <NUM> is shown in <FIG> and <FIG> as being held within the axial bore <NUM> of the cam <NUM> by means of the exterior lock cylinder <NUM>. The exterior lock cylinder <NUM> is so constructed that the end of the exterior lock cylinder <NUM> which is in the region of the cam <NUM>, fits within the axial bore <NUM> of the cam <NUM> to such an extent that it holds the torsion ring <NUM> in the first state within the cam <NUM>. As will be described later, removal of the exterior lock cylinder <NUM> after vandalism of the cylinder lock actuator <NUM> results in nothing physically holding the torsion ring <NUM> in the first state within the cam <NUM>, and the torsion ring <NUM> is thus free to move axially along the axial bore <NUM> of the cam <NUM>.

After the cylinder lock actuator <NUM> is vandalised, such that the exterior lock cylinder <NUM> is removed, the torsion ring <NUM> may leave the first state and enter a second state. In the second state, the torsion ring <NUM> is no longer held at a particular axial position within the axial bore <NUM> by the exterior lock cylinder <NUM> and further rotation of the torsion ring <NUM> will not lead to rotation of the cam <NUM>. In some embodiments, as shown in <FIG> for example, the torsion ring <NUM> will be completely free to be removed from the axial bore <NUM> of the cam <NUM>. In other embodiments, for example as shown in <FIG>, the torsion ring <NUM> is held within the axial bore <NUM> of the cam <NUM>. <FIG> shows the torsion ring <NUM> held within the axial bore <NUM> by means of a swaged lip <NUM>, such that the torsion ring <NUM> is able to move axially within the axial bore <NUM> of the cam <NUM>, however it is now in a second state such that the torsion ring <NUM> is able to rotate but will not transmit torque from this rotation through to the cam <NUM>. Allowing the torsion ring <NUM> to stay within the axial bore of the cam <NUM> provides a physical mechanism which thwarts a burglar's attempts to gain complete access to the interior of the cam <NUM>. The freely rotatable torsion ring <NUM> as shown in <FIG>, for example, minimises the possible angles at which the burglar can insert tools within the axial bore <NUM> of the cam <NUM>, whilst also providing a freely rotatable element which has no mechanism of transferring torque or any other forces to the cam <NUM>. This, at the very least, will inconvenience the burglar in trying to damage the cylinder lock actuator <NUM> further, and will further cause the burglar to spend extra time and effort trying to further vandalise the cylinder lock actuator <NUM> thereby increasing the chances of discovery.

The clutch mechanism <NUM> further comprises an interior drive bar <NUM> and an exterior drive bar <NUM>. The use of drive bars <NUM>, <NUM> in clutch mechanisms is well-known, the specific interaction of the interior drive bar <NUM> and exterior drive bar <NUM> with the torsion ring <NUM> of the present invention, however, is not known. Each of the interior drive bar <NUM> and exterior drive bar <NUM> are provided with respective drive bar lugs 15a, 16a. The respective lugs 15a, 16a on the respective drive bars <NUM>, <NUM> can best be seen in <FIG>. The torsion ring <NUM> is provided with a torsion ring slot 14a in the interior circumferential surface of the torsion ring <NUM>, the torsion ring slot 14a extending radially outward and having a form which matches the form of each of the drive bar lugs 15a, 16a. The torsion ring slot 14a will thus accommodate the respective drive bar lug 15a, 16a of whichever drive bar <NUM>, <NUM> is engaged with the torsion ring <NUM>, such that rotation of the engaged drive bar <NUM>, <NUM> will transmit the torque via the respective drive bar lug 15a, 16a to the torsion ring slot 14a. When the torsion ring <NUM> is held in the cylinder lock actuator <NUM> in the first state, rotation of the torsion ring <NUM> leads to rotation of the cam <NUM>.

Each of the drive bars <NUM>, <NUM> is held within the axial bore <NUM> of the cam <NUM> in an axially moveable manner. The drive bars <NUM>, <NUM> can consequently be moved axially within the axial bore <NUM>, in <FIG> this is from left to right in the figure. Whichever of the drive bars <NUM>, <NUM> is engaged with the torsion ring <NUM>, leads to rotation of that drive bar rotating the torsion ring <NUM> and consequently the cam <NUM>. In <FIG>, because the key <NUM> is located within the exterior lock cylinder <NUM>, the cylinder lock actuator <NUM> is configured such that the key <NUM> pushes the exterior drive bar <NUM> further within the axial bore <NUM> of the cam <NUM>, thus ensuring that the exterior drive bar <NUM> is engaged with the torsion ring <NUM>; this engagement meaning that the exterior drive bar lug 16a is located within the torsion ring slot 14a. With the exterior drive bar <NUM> of the clutch mechanism <NUM> engaged within the torsion ring <NUM>, rotation of the key <NUM> will lead to the exterior lock cylinder <NUM> rotating and the rotation of this is transmitted to the exterior drive bar <NUM>. The exterior drive bar <NUM> is held within the exterior lock cylinder <NUM> in an axially moveable manner, but in a rotationally fixed manner. The exterior drive bar <NUM> is not able to rotate with respect to the exterior lock cylinder <NUM>, and rotation of the exterior lock cylinder <NUM> leads to rotation of the exterior drive bar <NUM>. In an analogous manner, the interior drive bar <NUM> is held in an axially moveable and rotationally fixed manner within the interior lock cylinder <NUM>. This configuration means that the interior drive bar <NUM> may move axially within the interior lock cylinder <NUM> and axial bore <NUM> of the cam, but cannot rotate with respect to the interior lock cylinder <NUM>. Rotation of the interior lock cylinder <NUM> leads to rotation of the interior drive bar <NUM> - which will be transmitted to the cam <NUM> when the interior drive bar <NUM> is engaged with the torsion ring <NUM>.

The cylinder lock actuator <NUM> further comprises a mechanism of fixing the rotation of the cam with respect to the interior lock cylinder <NUM>. This is shown in <FIG>, <FIG> and <FIG> in particular and will be discussed in greater detail below. The mechanism of attaching the cam <NUM> to the interior lock cylinder <NUM> after lock vandalism and removal of the exterior lock cylinder <NUM> according to the present invention, may utilise an embodiment of an interior drive bar <NUM> within the clutch mechanism <NUM> as will be described in detail below in relation to <FIG> and <FIG>. The interior drive bar <NUM> as discussed in relation to <FIG> and <FIG> below is one embodiment which interacts with the torsion ring <NUM>; the torsion ring <NUM> can, however, be employed with known drive bar mechanisms to increase the security of any such cylinder lock actuator <NUM>. In describing such general applications of the torsion ring <NUM>, the interaction of the clutch mechanism <NUM> will firstly be described in general terms to be applied to any cylinder lock actuator <NUM>.

In a known cylinder lock actuator <NUM>, the mechanism described above by which the exterior drive bar <NUM> is pushed into alignment with the torsion ring <NUM> can be used with the interior lock cylinder <NUM>. If the interior lock cylinder <NUM> is so structured that the thumb turn <NUM> or interior key operated lock cylinder were to provide a pushing force to axially move the interior drive bar <NUM> into engagement with the torsion ring <NUM>, the interior drive bar <NUM>, by means of the interior drive bar lug 15a engaging with the torsion ring slot 14a, would control rotation of the torsion ring <NUM>. In this manner, whichever of the interior lock cylinder <NUM> or exterior lock cylinder <NUM> controls the clutch mechanism <NUM>, such that the relevant drive bar <NUM>, <NUM> is engaged with the torsion ring <NUM>, the rotation of the lock cylinder in control of the clutch mechanism <NUM> causes rotation of the cam <NUM> and the lock to be locked or unlocked. It will further be appreciated that in such a lock cylinder actuator <NUM>, which is not shown in any of the Figures, the removal of the exterior lock cylinder <NUM> as described above with regard to <FIG>, would remove the exterior lock cylinder <NUM> as well as the exterior drive bar <NUM>. As already disclosed, removal of the exterior lock cylinder <NUM> removes the physical urging of the torsion ring <NUM> into the first state where torque applied to the torsion ring <NUM> is further applied to the cam <NUM>. Removal of the exterior lock cylinder <NUM> allows the torsion ring <NUM> to axially move along the axial bore <NUM> of the cam <NUM>, as described above, and further rotation of the torsion ring <NUM> does not transfer torque to the cam <NUM>, as the torsion ring <NUM> would have left said first state. As shown in <FIG>, the torsion ring <NUM> may simply fall out of the axial bore <NUM> of such a cylinder lock actuator <NUM>, or the torsion ring <NUM> may be held within the axial bore <NUM> of the cam <NUM> by means of the swaged lip <NUM>, as shown in <FIG>. In each of <FIG> and <FIG>, the specific interior lock cylinder <NUM> as shown in said Figures, could simply be replaced with a copy of the exterior lock cylinder <NUM> as shown in <FIG>, in such a case the clutch mechanism <NUM> as described above could be appropriately used with any cylinder lock actuator <NUM>. The particular feature of the torsion ring <NUM> being held within the axial bore <NUM> is, therefore, not limited to the use with the further aspects of the cylinder lock actuator <NUM> described herein. The clutch mechanism <NUM>, and in particular the torsion ring <NUM>, of the present disclosure may therefore be used with any cylinder lock actuator <NUM> and provides the further benefit, when the torsion ring <NUM> remains within the axial bore <NUM> of the cam <NUM>, of providing a physical item which serves no purpose in turning the cam but which provides both a distraction and physical impediment to a burglar's further attack after removing the exterior lock actuator <NUM>. The torsion ring <NUM> is, therefore, a separate invention in its own right and can be used in other known cylinder lock actuators <NUM>.

As has been discussed above, the torsion ring <NUM> has a first state in which the rotation of the torsion ring <NUM> is transmitted to rotate the cam <NUM>. A second state of the torsion ring <NUM> exists in which the rotation of the torsion ring <NUM> within the axial bore <NUM> of the cam <NUM> will not lead to any torque being transmitted to the cam <NUM>, such that the torsion ring <NUM> can rotate freely. As also described above, either the torsion ring <NUM> will be easily removable from the axial bore <NUM> of the cam <NUM>, or the torsion ring <NUM> can be held within the actual bore <NUM> of the cam <NUM> by means of the swaged lip <NUM>. In order to allow the torsion ring <NUM> to rotate freely without transmitting torque to the cam <NUM>, the torsion ring <NUM> can be provided with an extension which interacts with an element within the axial bore <NUM> of the cam <NUM>, such that the relative rotation between the torque ring <NUM> and cam <NUM> is not possible. The extension on the torsion ring <NUM> can take a number of different forms, the Figures showing one particular option thereof. By providing a pocket <NUM> on the outer circumferential side of the torsion ring <NUM>, as seen in <FIG>, a removable element can be located therein such that the removable element extends beyond the outer circumference of the torsion ring <NUM> to create the appropriate extension. <FIG> shows the extension being in the form of a bearing ball <NUM>, however this is by way of example only. It would be appreciated that a bearing ball <NUM> is easy to manufacture or obtain from suppliers, and can readily be integrated into the cylinder lock actuator <NUM>. Alternatively, the bearing ball <NUM> may be replaced by a cube, heptagon, decagon or any other appropriate shape such that parts of the extension will extend out of the pocket <NUM> and beyond the outer circumference of the torsion ring <NUM>. A slot <NUM> may be provided on the interior of the axial bore <NUM>, as shown in <FIG>, slot <NUM> allowing for the torsion ring <NUM> to slide into the axial bore <NUM> with bearing ball <NUM>, or equivalent, held within the pocket <NUM>. With the ball nearing <NUM> within the slot <NUM>, it will be appreciated that the bearing ball <NUM> will transmit any torque applied to the torsion ring <NUM> via the side of the pocket <NUM> to the slot <NUM> on the interior of the axial bore <NUM> of the cam <NUM>.

The end of the axial bore <NUM> in the cam <NUM> which is on the exterior side of the cylinder lock actuator <NUM>, is provided with a region of a first diameter. This first diameter section <NUM>, seen in <FIG>, has a diameter which allows the torsion ring <NUM> to enter into the axial bore <NUM> of the cam <NUM> and without presence of the bearing ball <NUM>, will allow for the torsion ring <NUM> to freely rotate without transmitting torque to the cam <NUM>. If, however, the bearing ball <NUM> is present and within the pocket <NUM> of the torsion ring <NUM>, when this assembly is positioned within the first diameter section <NUM> of the axial bore <NUM>, rotation of the torsion ring <NUM> will transfer the torque through the bearing ball <NUM> to the slot <NUM> of the axial bore <NUM> as described above. The first diameter section <NUM> extends a distance within the axial bore <NUM> to a step <NUM> which signals the start of a second diameter section <NUM> of the axial bore <NUM>. It is preferred that a straight sided step <NUM> is provided, as this is straightforward to manufacture and provides a definite stop to the torsion ring <NUM> entering further into the axial bore <NUM> of the cam <NUM>. The interior diameter of the second diameter section <NUM> is smaller than the outer diameter of the torsion ring <NUM>, thus meaning that the torsion ring <NUM> can only extend into the axial bore <NUM> in the region of the first diameter section <NUM>. When the bearing ball <NUM> is in the pocket <NUM> of the torsion ring <NUM>, the torsion ring <NUM> can be positioned within the first diameter section <NUM> such that the bearing ball <NUM> is within the slot <NUM> and the bearing ball <NUM> also rests against the step <NUM>. The bearing ball <NUM> is removable from the pocket <NUM>, thus meaning that the step <NUM> holds the bearing ball <NUM> within the pocket <NUM>. Positioning the torsion ring <NUM> with the bearing ball <NUM> in the pocket <NUM> fully within the first diameter section <NUM>, such that the bearing ball <NUM> is held within the pocket <NUM> by means of the step <NUM>, is the first state of the torsion ring <NUM>. In this state, rotation applied to the torsion ring <NUM> will ensure that the torque is transmitted via the bearing ball <NUM> through to the cam <NUM>. As the bearing ball <NUM> is held within the pocket <NUM> by the step <NUM>, or even pushed within the pocket <NUM>, the torsion ring <NUM> will always be able to transmit torque to the cam <NUM> and the torsion ring <NUM> is maintained in the first state.

It will be appreciated that the presence of the exterior lock cylinder <NUM> ensures that the torsion ring <NUM> is pushed up to the full extent of the first diameter section <NUM>, such that the bearing ball <NUM> is held within the pocket <NUM>. The innermost end of the exterior lock cylinder <NUM> is so sized that it will fit within the first diameter section <NUM>: that is, the external diameter of at least the end of the exterior lock cylinder <NUM> is smaller than the inner diameter of the first diameter section <NUM>. Ideally, the second diameter section <NUM> has an interior diameter which is smaller than the exterior diameter of the exterior lock cylinder <NUM>. The presence of the exterior lock cylinder <NUM> ensures that the torsion ring <NUM> remains in the first state, that is the torsion ring <NUM> remains fully abutting the step <NUM> such that the bearing ball <NUM> remains within the pocket <NUM>. It will be appreciated, however, that once the lock is vandalised and the exterior lock cylinder <NUM> is removed, there is nothing holding the torsion ring <NUM> in a fully engaged manner in the first diameter section <NUM> and the torsion ring <NUM> is free to move axially along the axial bore <NUM> and away from the step <NUM>. Once the torsion ring <NUM> is not held in place by the exterior lock cylinder <NUM>, and can move away from the step <NUM>, nothing holds the bearing ball <NUM> within the pocket <NUM> such that this can then fall out of the pocket <NUM> and slot <NUM>. Once the bearing ball <NUM> has fallen out of the pocket <NUM> and slot <NUM>, there is nothing which is present to transmit the torque from the torsion ring <NUM> through to the cam <NUM>, and the torsion ring <NUM> is in a second state. The second state is defined as any state in which rotation of the torsion ring <NUM> does not lead to rotation of the cam <NUM>. As a further matter, the removal of the exterior lock cylinder <NUM> means that there is no longer any element physically holding the torsion ring <NUM> within the cam <NUM>: this further means that the torsion ring <NUM> is free to be removed and may simply fall out, or be pushed out by other elements within the cam <NUM>, after removal of the exterior lock cylinder <NUM>.

Whilst the embodiment above shows the bearing ball <NUM> being present in the pocket <NUM> on the external surface of the torsion ring <NUM> and within slot <NUM> along the inner circumferential surface of the first diameter section <NUM>, this is by way of example only. It would also be possible to provide an indent on the surface of the step <NUM>, the indent aligning with a removable protrusion extending axially from the rear face of the torsion ring <NUM> into said indent. Instead of the bearing ball <NUM> extending radially outward from the outer circumferential surface of the torsion ring <NUM>, the bearing ball <NUM>, or any other appropriate item, could be held in a removable manner in a pocket in the rear face of the torsion ring <NUM> and in alignment with the indent on the step <NUM> within the cam <NUM>. Once again, the torsion ring <NUM> will be held in the first state, that is the extension being held within the indent on the step <NUM>, by the presence of the exterior lock cylinder <NUM>. Removal of the exterior lock cylinder <NUM> would allow for the torsion ring <NUM> to move away from the step <NUM>, such that the bearing ball <NUM>, or other appropriate element, would fall out of the pocket in the rear face of the torsion ring <NUM> and out of the indent in the step <NUM>. This would transfer the torsion ring <NUM> into the second state, where the torsion ring <NUM> would be able to rotate freely in the axial bore <NUM> of the cam <NUM> without transmitting torque through to the cam <NUM>.

A further possibility for defining the torsion ring <NUM> is that the extension in the outer circumferential surface of the torsion ring <NUM> or in the rear face of the torsion ring <NUM> in the second example given above, is not removable. In such a scenario, removal of the exterior lock cylinder <NUM> after vandalism allows the torsion ring to move axially along the axial bore <NUM> and to fall out of the axial bore <NUM> as shown in <FIG>, thus taking the permanent extension with it and out of the slot <NUM> in the axial bore <NUM>. Alternatively, the forward facing extension from the rear face of the torsion ring <NUM> would be able to move out of alignment with the indent in the step <NUM>, such that the torsion ring <NUM> would then be free to rotate within the first diameter section <NUM> of the axial bore <NUM>. In the case where the extension is radially protruding from the outer circumferential surface of the torsion ring <NUM> and is not removable, the torsion ring <NUM> would not be able to freely rotate within the axial bore <NUM>, as the extension would be in the slot <NUM>. However, the torsion ring <NUM> could easily fall out of the axial bore <NUM> of the cam <NUM> and therefore would not be in a position to transmit torque at all, as it would no longer form part of the cylinder lock actuator.

Further aspects of the interior lock cylinder <NUM> can most clearly be seen in <FIG> and <FIG> and relate to fixing the cam <NUM> to the interior lock cylinder <NUM>. In particular, the end of the interior lock cylinder <NUM> which is held within the axial bore <NUM> of the cam <NUM>, has a diameter which is smaller than the interior diameter of the second diameter section <NUM>. The end of the interior lock cylinder <NUM> also comprises a blind hole <NUM> or indent, into which the interior drive bar <NUM> can slidably engage. The interior drive bar <NUM> is able to axially move within the blind hole <NUM> of the interior lock cylinder <NUM>, however the interior drive bar <NUM> is not able to rotate with respect to the interior lock cylinder <NUM> and is held within the blind hole <NUM> in a manner that does not permit relative rotation. The interior drive bar <NUM> can move in and out of complete engagement with the blind hole <NUM>, but cannot rotate with respect thereto. By configuring the interior drive bar <NUM> so that it cannot rotate with respect to the interior lock cylinder <NUM>, ensures that rotation of the interior lock cylinder <NUM> leads to rotation of the interior drive bar <NUM>. When the interior drive bar <NUM> is engaged with the torsion ring <NUM>, rotation of the interior lock cylinder <NUM> thus leads to rotation of the cam <NUM>.

The interior drive bar <NUM> preferably comprises two interacting elements. The first part of the interior drive bar <NUM> comprises a generally cylindrically extending form which comprises the drive bar lug 15a. The second part of the interior drive bar <NUM> comprises a drive bar fixed part <NUM> and a drive bar spring <NUM>. The drive bar spring <NUM> can be seen in <FIG> and <FIG>, this being located between the drive bar fixed part <NUM> and the cylindrical part of the drive bar <NUM>. The drive bar spring <NUM> is generally affixed to the drive bar fixed part <NUM>, and provides a repulsive force between the drive bar fixed part <NUM> and the cylindrical part of the interior drive bar <NUM>. The effect of the essentially spring loaded interior drive bar <NUM>, can best be seen in <FIG>. As can be seen in <FIG>, the lock prior to vandalism is one in which the interior drive bar <NUM> is spring-loaded into engagement with the torsion ring <NUM>. Indeed, the present cylinder lock actuator <NUM> is one in which the interior lock cylinder <NUM> is generally biased to control the rotation of the torsion ring <NUM>. Only when the key <NUM> is inserted into the exterior lock cylinder <NUM>, as shown in <FIG>, will the exterior drive bar <NUM> push against the drive bar spring <NUM> to disengage the interior drive bar <NUM> from the torsion ring <NUM>. Removal of the key <NUM> means that the drive bar spring <NUM> pushes the cylindrical part of the interior drive bar <NUM> against the exterior drive bar <NUM>, pushing the exterior drive bar <NUM> out of engagement with the torsion ring <NUM> and ensuring that the interior drive bar <NUM> is in engagement with the torsion bar <NUM>. Basically, the natural state of the cylinder lock actuator <NUM> without the presence of the key <NUM> fully inserted, is one in which the interior lock cylinder <NUM> is always engaged to control the rotation of the cam <NUM>. As can be seen in <FIG>, the blind hole <NUM> is structured to fully hold the interior drive bar fixed part <NUM> at the end of the blind hole <NUM>, allowing the drive bar spring <NUM> to extend and push the cylindrical part of the interior drive bar <NUM> into engagement with the torsion ring <NUM>. In this way, it is clear that no part of the thumb turn <NUM> is needed to push the interior drive bar into engagement with the torsion ring <NUM>, as it is only the presence of the key <NUM> in the exterior lock cylinder <NUM> which removes rotational control of the cam <NUM> from the interior lock cylinder <NUM>. If the thumb turn <NUM> were to be replaced by an interior key operated lock cylinder, this would function in exactly the same way and the presence or absence of a key within the interior lock cylinder <NUM> would not affect the engaged position of the interior drive bar <NUM> with the torsion ring <NUM>. As will be appreciated, after the lock is vandalised and the torsion ring <NUM> is moved out of the first state, or indeed is removed from the axial bore <NUM> of the cam <NUM> completely, the interior drive bar <NUM> will simply be held within the blind hole <NUM>, or may even itself exit the axial bore <NUM> of the cam <NUM>. Fixing the drive bar fixed part <NUM> in a permanent manner within the blind hole <NUM> is possible, but is not necessary and in fact may even be undesirable. Allowing the entirety of the interior drive bar <NUM> to be removable from the axial bore <NUM> means that a burglar would see only the interior of the cam <NUM> and the blind hole <NUM> of the interior lock cylinder <NUM>, providing nothing to further attack.

As can be seen in <FIG>, it is also possible to provide an ejection spring <NUM> within the blind hole <NUM>, in order to promote that all elements of the clutch mechanism <NUM> are expelled or ejected from the axial bore <NUM> of the cam <NUM> when the lock is vandalised. The ejection spring <NUM> as shown in <FIG> has the structure of a cone spring, wherein this cone spring would be fully compressed between the interior drive bar fixed part <NUM> and the end of the blind hole <NUM> when the cylinder lock actuator <NUM> is assembled and prior to vandalising. It will be appreciated that the ejection spring <NUM> will provide a further force on the interior drive bar fixed part <NUM>, pushing this further outward and further ensuring engagement of the interior drive bar <NUM> with the torsion ring <NUM>. Upon removal of the exterior lock cylinder <NUM> by vandalism, the exterior drive bar <NUM> will fall out of the axial bore of the cam <NUM>, and the torsion ring <NUM> will leave the first state and will either be ejected or left in a rotationally free manner within the first diameter section <NUM> of the axial bore <NUM> - i.e. it would enter the second state. The interior drive bar <NUM> will then be forced out of the axial bore <NUM> by the force of the ejection spring <NUM>, thus facilitating the expulsion of both drive bars <NUM>, <NUM> from the axial bore <NUM>. If the axial bore <NUM> does not have the swaged lip <NUM>, it is clear the ejection spring <NUM> would also provide a force on the torsion ring <NUM> to expel this from the axial bore <NUM>. The ejection spring <NUM> need not be a cone spring, but could be any compression spring, and advantageously the ejection spring <NUM> could be held within the blind hole <NUM> of the interior lock cylinder <NUM>. If the ejection spring <NUM> is fixed within the blind hole <NUM>, either frictionally or by welding or by adhesive or by moulding together, or any other permanent mechanism suitable for keeping the ejection spring <NUM> within the blind hole <NUM>, after the lock is vandalised the spring will be located and kept within the axial bore <NUM> of the cam <NUM>. The presence of the fixed ejection spring <NUM>, or at least one that is frictionally held to an appropriate degree that its removal is non-trivial, provides a further problem to the burglar trying to gain access to the inner workings of the cylinder lock actuator <NUM>. Should the burglar try to use a drill to gain further access to elements of the cylinder lock actuator <NUM>, the ejection spring <NUM> would make drilling extremely inconvenient or even impossible. This would again delay the burglar and could dissuade the burglar from continuing to attack the lock actuator <NUM>, and would certainly give greater opportunity for the burglar to be seen during the attempt to enter the building.

Rather than having a separate ejection spring <NUM> acting on the interior drive bar fixed part <NUM>, another embodiment is for the interior drive bar fixed part <NUM> to comprise a spring itself acting against the end of the blind hole <NUM>. Such a design would prove a spring force that both leads to the interior drive bar <NUM> being usually engaged with the torsion ring <NUM> and also being strong enough to eject the interior drive bar <NUM>, torsion ring <NUM> and exterior drive bar <NUM> if the lock is vandalised. Such a design for the interior drive bar <NUM> is not shown in the figures. This integrated ejection interior drive bar <NUM> would not leave the spring within the blind hole <NUM> of the interior lock cylinder <NUM>, but would assist in ensuring the removal of the clutch mechanism <NUM> with or without leaving the torsion ring <NUM> in the axial bore <NUM>. It is also possible to provide the interior drive bar <NUM> with the cylindrical drive bar element and a drive bar spring <NUM> alone. The drive bar spring <NUM> would act against the end of the blind hole <NUM> to push the cylindrical part of the interior drive bar <NUM> into engagement with the torsion ring <NUM>, and upon the lock being vandalised would also assist in ejecting the clutch mechanism <NUM> out of the axial bore <NUM> of the cam <NUM>.

Further aspects of the security features of the current cylinder lock actuator <NUM> can be appreciated when comparing <FIG> and <FIG>. In <FIG>, prior to the cylinder lock actuator <NUM> being vandalised, the cam <NUM> can be controlled via the clutch mechanism <NUM>. The cam <NUM> rotates independently of each of the interior lock cylinder <NUM> and exterior lock cylinder <NUM>, when the respective lock cylinder <NUM>, <NUM> is not engaged with the clutch mechanism <NUM>. After the lock has been vandalised and the exterior lock cylinder <NUM> is removed, as shown in <FIG>, the cylinder lock actuator <NUM> enters a vandalised condition where the cam <NUM> is permanently engaged with the interior lock cylinder <NUM>. In this vandalised state, the cam <NUM> is locked to the interior lock cylinder <NUM> and the cam <NUM> cannot rotate with respect to the interior lock cylinder <NUM>. Crucially, the movement of the cam <NUM> is irrespective of any aspect of the clutch mechanism <NUM>, is achieved by entirely independent means and nothing held within the clutch mechanism triggers or influences the locking of the cam <NUM> to the interior lock cylinder <NUM>. When comparing <FIG> and <FIG>, the cam <NUM> has a locking slot <NUM> therein. Whilst the locking slot <NUM> is shown extending through the wall of the cam <NUM>, this is by way of example only. The locking slot <NUM> may, in fact, be an indent on the interior side of the axial bore <NUM> of the cam <NUM>, providing a blind hole or indent which does not pass through the side wall of the cam <NUM>. The number of locking slots <NUM> is not limited, and it is contemplated that two locking slots <NUM> will be present within the cam <NUM>, generally one on either side of the cylinder lock actuator <NUM>. The means of fixing the cam <NUM> to the interior locking cylinder <NUM> is by means of one or more locking pins <NUM>. The locking pins <NUM> are held within the interior lock cylinder <NUM> and are preferably biased out of the interior locking cylinder <NUM>. As can be seen in the exploded view of <FIG>, the interior lock cylinder <NUM> comprises a locking pin hole or bore <NUM> in a position behind the blind hole <NUM>. This position is at a location more interior and away from the cam <NUM> than the blind hole <NUM>, and crucially the locking pin hole <NUM> is an entirely separate hole or slot in the interior lock cylinder <NUM> from the blind hole <NUM>. This means that the locking pin hole <NUM> and locking means for holding the cam <NUM> in rotational alignment with the interior lock cylinder <NUM>, are completely separate from the blind hole <NUM> and any elements of the clutch mechanism <NUM>. This has the further benefit that the mechanism for fixing the cam <NUM> to the interior lock cylinder <NUM> after vandalism is not accessible through the axial bore <NUM> of the cam, as the locking pin hole <NUM> is positioned separate from the blind hole <NUM> holding the clutch mechanism <NUM> and has the material making up the interior lock cylinder <NUM> to protect it.

The locking pin hole <NUM> can either be a single blind hole in which a single locking pin <NUM> is located, or as shown in <FIG>, the locking pin hole <NUM> can be a through hole passing through from one side of the interior lock cylinder <NUM> to the other side thereof. In this scenario, two locking pins <NUM> are located within the locking pin hole <NUM> and a single locking pin spring <NUM> is positioned there-between to bias the locking pins <NUM> out of the locking pin hole <NUM>. In the scenario where a single blind hole is present for the locking pin hole <NUM>, the locking pin spring <NUM> would be positioned between the end of the locking pin blind hole and the locking pin <NUM> to bias the locking pin <NUM> out of the locking pin blind hole.

As can be seen in <FIG>: prior to the cylinder lock actuator <NUM> being vandalised, the cam <NUM> is so positioned that the locking slot <NUM> blocks the locking pin <NUM> from exiting the locking pin hole <NUM>. In this arrangement, the end of the locking pin <NUM> is pushed against the interior surface of the axial bore <NUM>, but does not stop rotation of the cam <NUM> and normal operation of the locking pin actuator <NUM>. When the cylinder lock actuator <NUM> is vandalised, however, the cam <NUM> is located in an orientation such that the locking slot <NUM> now aligns with the position of the locking pin <NUM>, and the locking pin <NUM> is biased into the locking slot <NUM>. The same would occur if the locking slot does not extend through the surface of the cam <NUM>, but rather forms an indent on the interior surface thereof. Once the locking pin <NUM>, or locking pins in the example shown in <FIG>, have extended into the aligned respective locking slot or locking slots <NUM>, the cam <NUM> is then mechanically connected with the interior lock cylinder <NUM> and cannot rotate freely without rotation of the interior locking cylinder <NUM>. As will be appreciated, the interior lock cylinder <NUM> can only be rotated by rotating the thumb turn <NUM> or, if the thumb turn <NUM> is replaced by a key cylinder, by introducing a key into the interior lock cylinder <NUM>, properly aligning the key and allowing rotation of the interior lock cylinder <NUM> which will also rotate the affixed cam <NUM>. As the interior lock cylinder <NUM> either in the form of the thumb turn <NUM> or in the form of a key operated lock cylinder cannot be operated by rotating the cam <NUM>, the cam <NUM> is locked in rotational alignment with the interior lock cylinder <NUM> and cannot be rotated by the burglar after vandalising the lock from the exterior side of the door. That is, because the interior lock cylinder can only be rotated by someone on the interior side of the door and because the cam <NUM> is rotatably fixed with respect to the interior lock cylinder <NUM> after lock vandalism, the burglar on the exterior of the door cannot rotate the cam <NUM> because the interior lock cylinder <NUM> blocks rotation thereof. Of course, a person on the inside of the door can engage the interior lock cylinder <NUM> and rotate this, thus leading to rotation of the cam <NUM>; this allows someone on the interior side of the door to always open the lock and exit the building. This is a fundamental safety requirement and is met by the cylinder lock actuator <NUM> of the present disclosure.

It should be noted that the locking slot <NUM> is shown as an extended slot in the figures, however the locking slot <NUM> could be simply a round hole which accommodates the size of the locking pin <NUM> to allow the locking pin <NUM> to extend into the locking slot <NUM>, even when circular, thus ensuring the cam <NUM> and the interior lock cylinder <NUM> cannot freely rotate independently upon lock vandalism. The use of the locking slot <NUM> allows for the locking pin <NUM> to engage with the locking slot <NUM> at a greater number of relative angles between the locking pin <NUM> and locking slot <NUM>, thus improving the locking together of these two elements - the limited relative rotation which the locking slot <NUM> then affords is not, however, enough for the burglar to operate the cam <NUM>. Furthermore, the locking pin <NUM> can have a structure such that the outer end has a narrower diameter which will fit within the locking slot <NUM>, the inner end of the locking pin <NUM> having a larger diameter which will not pass into the locking slot <NUM>. In this way, when the locking pin <NUM> is biased into engagement with the locking slot <NUM>, it cannot pass all the way through the locking slot <NUM> and will therefore properly function to hold the cam <NUM> rotationally aligned with the interior lock cylinder <NUM>.

In order that the cam <NUM> can be located such that the locking slot <NUM> aligns with the locking pin <NUM>, the cam <NUM> is held on the outer surface of the interior lock cylinder <NUM> in an axially moveable manner. As already mentioned, the outer diameter of the end of the interior lock cylinder <NUM> which is located within the axial bore <NUM>, is smaller than the second diameter section <NUM>. This allows for the cam <NUM> to not only rotate around the interior lock cylinder when the exterior lock cylinder <NUM> is engaged via the clutch mechanism <NUM>, but also allows the cam <NUM> to slide axially along the outer surface of the interior lock cylinder <NUM> after the cylinder lock actuator <NUM> has been vandalised. Once the cylinder lock actuator <NUM> has been vandalised, there is nothing holding the cam <NUM> in axial alignment with the interior lock cylinder <NUM>, thus meaning that the cam <NUM> is free to move axially along the outer surface of the interior lock cylinder <NUM>. If the cam <NUM> moves axially away from the interior lock cylinder <NUM>, it is then clear that at some point the locking slot <NUM> will align with the locking pin <NUM> and the locking pin <NUM> will be able to engage with the locking slot and stop further axial movement whilst also linking the cam <NUM> and the interior lock cylinder <NUM> to stop relative rotation between the two, aside from that which the locking slot <NUM> might afford.

Rather than leaving to chance the burglar pulling the cam <NUM> forward and thereby aligning the locking slot <NUM> with the locking pin <NUM>, the cylinder lock actuator <NUM> of the invention comprises means which bias the cam <NUM> away from the interior lock actuator <NUM>. The principle of operation is that upon removal of the exterior lock cylinder <NUM> by vandalism, the biasing means act to push the cam <NUM> away from the interior lock actuator <NUM> to the extent that the locking slot <NUM> will align with the locking pin <NUM> and the two will engage. The biasing means can be seen in <FIG> and <FIG> and in the embodiment shown take the form of a cam spring <NUM>, this being a compression spring. A compressible element, perhaps rubber rings, or a resilient foam or other means could also be used as the biasing means for the cam <NUM>. The cam spring <NUM> is so aligned and positioned that it acts to push the cam <NUM> away from the interior lock cylinder <NUM>. When comparing the position of the cam <NUM> in <FIG> and <FIG>, it will be noted that the cam <NUM> in <FIG>, the non-vandalised cylinder lock actuator <NUM> as shown in <FIG>, is positioned more closely to the interior lock cylinder <NUM>. After the cylinder lock actuator <NUM> is vandalised, the cam <NUM> is free to move axially along the outer surface of the interior lock cylinder <NUM>, and is biased and pushed by means of the cam spring <NUM>, until the locking slot <NUM> aligns with the locking pin <NUM> and the locking pin <NUM> holds the cam <NUM> with the interior lock cylinder <NUM>. The cam spring <NUM>, therefore, provides a completely isolated and independent means of pushing the cam <NUM> into locking alignment through the use of the locking slot <NUM> and locking pin <NUM>.

As shown in <FIG>, the exterior surface of the interior lock cylinder <NUM> has a first end with a first diameter which will fit within the second diameter section <NUM> of the axial bore <NUM>, which extends far enough along the interior lock cylinder <NUM> to allow this to fully extend into the axial bore <NUM> and position the interior drive bar <NUM> for alignment with the torsion ring <NUM>. The interior lock cylinder also has a second region with a larger diameter and this forms a discontinuity and this is shown as spring step <NUM> in <FIG>. The spring step <NUM> is the surface against which the cam spring <NUM> acts to push the cam <NUM> away from the interior lock cylinder <NUM>. The cylinder lock actuator <NUM> functions by simply positioning the cam spring <NUM> between the interior end of the cam <NUM> and the cam step <NUM>, and the cam spring <NUM> will then act to push the cam <NUM> into locking alignment by means of the locking slot <NUM> and locking pin <NUM>. In order to properly hold the cam spring <NUM> in position, a spring pocket <NUM> can be formed on the interior end of the axial bore <NUM> of the cam <NUM>. The spring pocket <NUM> is a region of increased diameter in the axial bore <NUM>, wherein this will then house the cam spring <NUM>. The cam spring <NUM> has an interior diameter which is greater than the diameter at the end of the first lock cylinder <NUM>, so that the cam spring <NUM> can slide over the first interior lock cylinder <NUM>. The diameter of the cam spring <NUM> is smaller than the diameter of the spring step <NUM>, thus meaning that the cam spring <NUM> is only able to move along the smaller diameter end to the interior lock cylinder <NUM>. The spring pocket <NUM> on the cam <NUM> has a diameter greater than the outer diameter of the cam spring <NUM>, thus meaning that it can slot over the cam spring <NUM> and hold the cam spring <NUM> properly in position. In the pre-vandalised condition of the cylinder lock actuator <NUM> shown in <FIG>, the cam spring <NUM> is fully compressed, once the lock is vandalised as shown in <FIG> the cam spring <NUM> can decompress slightly and push the cam <NUM> into locking alignment as shown in <FIG>.

As will be appreciated when comparing <FIG> and <FIG>, if the cylinder lock actuator <NUM> is vandalised, the lug <NUM> will move within the lug slot <NUM>. When the cam <NUM> is biased into the locked orientation as shown in <FIG>, the lug <NUM> will be pushed against the exterior side of the lug gap <NUM>. Obviously, if the lug <NUM> were to be held in the cam <NUM> in a non-moveable manner, this could stop the cam <NUM> from extending forward sufficiently to allow the cam <NUM> to lock to the interior lock cylinder <NUM>. To this end, the lug <NUM> is held in an axially moveable manner within the cam <NUM>, such that when the cam <NUM> is pushed forward by the cam spring <NUM> into a locked orientation, the lug <NUM> is moved axially with respect to the cam <NUM> so that it does not strike the housing <NUM> and rotation of the cam <NUM> is still possible. As shown in <FIG>, the lug <NUM> is provided with a lug bar <NUM>, this lug bar <NUM> extending through a lug bar hole <NUM> in the lug <NUM>. The lug <NUM> is held on the lug bar <NUM> with the lug bar <NUM> passing through the lug bar hole <NUM>, the lug <NUM> being able to slide along the lug bar <NUM>. In this manner, the lug <NUM> is able to slide with respect to the cam <NUM> and will not block rotation of the cam <NUM> when the lock is vandalised and the cam <NUM> has moved away from the interior lock cylinder <NUM>. In order to assist in moving the lug <NUM> and ensuring that the lug <NUM> does not impede rotation of the cam <NUM>, one or more lug springs <NUM> can be located between the lug <NUM> and the cam <NUM> in order to bias the lug <NUM> with respect to the cam <NUM>. It will be appreciated that the lug bar <NUM> is held within the cam <NUM> and an appropriate aperture is provided such that the upper part of the lug <NUM> can fit around the lug bar <NUM> within the cam <NUM> and move forward and backward along the lug bar <NUM> as required, and as the position of the cam <NUM> dictates. The lug springs <NUM> can be so designed as to bias the lug <NUM> into a location which will align with the lug gap <NUM> when the cylinder lock actuator <NUM> has not been vandalised. Movement of the lug <NUM> does not require a great amount of force, thus meaning that the lug springs <NUM>, if present, need only be strong enough to effect alignment of the lug <NUM> within the lug gap <NUM>. To this end, the force applied by the lug springs <NUM> onto the lug <NUM> is such that it will provide very little, if any, counter force to the movement of the cam <NUM> upon vandalism of the cylinder lock actuator <NUM> when the cam <NUM> strikes the side of the lug gap <NUM>. Furthermore, in the case that the cylinder lock actuator <NUM> has been vandalised and the lug <NUM> is resting against the inner face of the lug gap <NUM> once the cam <NUM> has moved into its locked orientation, the pressure of the lug <NUM> against the lug gap <NUM> (or interior of the lock itself) caused by the force of the lug springs <NUM> does not impede operation of the cylinder lock actuator <NUM> by a user on the interior of the door. In this way, the functioning of the cylinder lock actuator <NUM> from the interior of the door is assured after it is vandalised, as is the safety of the user.

Looking at <FIG>, this shows the non-vandalised state of the lock actuator <NUM> with the key <NUM> in the exterior lock cylinder <NUM>. The key <NUM> pushes the interior drive bar into engagement with the torsion ring <NUM>, such that rotation of the key <NUM> will rotate the interior drive bar <NUM> and through the torsion ring <NUM> will appropriately rotate the cam <NUM>. Removal of the key <NUM> from the exterior lock cylinder <NUM> puts the cylinder lock actuator <NUM> into the position shown in <FIG>. As seen in <FIG>, the biased interior drive bar <NUM> is pushed into engagement with the torsion ring <NUM>, such that the thumb turn <NUM> is able to operate the cylinder lock actuator <NUM> and rotation of the thumb turn <NUM> is transmitted through the interior drive bar <NUM> to the torsion ring <NUM> and the cam <NUM>. As shown, the thumb turn <NUM> is always in control of the cylinder lock actuator <NUM> unless the key <NUM> is fully inserted into the exterior lock cylinder <NUM>. If the thumb turn <NUM> were replaced by a key operated cylinder, the biased interior drive bar <NUM> would still always be in engagement with the torsion ring <NUM> unless the key <NUM> were placed in the exterior cylinder lock <NUM>.

Upon vandalising the cylinder lock actuator <NUM>, the exterior lock cylinder <NUM> is removed and the remaining parts may take the form as shown in <FIG>; as will be appreciated from the above, it is possible for the interior drive bar <NUM> and/or the torsion ring <NUM> to remain within the cam <NUM> in a non-functional state. Once the exterior lock cylinder <NUM> has been removed this no longer holds the cam <NUM> in position against the cam spring <NUM> and the cam spring <NUM> pushes the cam <NUM> away from the interior lock cylinder <NUM>, until the one or more locking slots <NUM> engages with the one or more respectively aligned locking pins <NUM>. The locking pins <NUM> are then biased into the locking slot <NUM>, whether this is the through slot as shown in the figures or an indent on the interior of the axial bore <NUM>, the cam <NUM> is then held in a fixed manner with regard to the interior lock cylinder <NUM>. Rotation of the cam <NUM> is then only possible by actuating the interior lock cylinder <NUM>, either by means of the thumb turn <NUM> shown or the key if a key operated interior lock cylinder <NUM> is present. This means that the burglar is unable to rotate the cam <NUM>, as it is locked properly to the interior lock cylinder <NUM>, but a person on the interior side of the cylinder lock actuator <NUM> is able to lock and unlock the lock as normal.

As shown in <FIG>, if the design allows for the torsion ring <NUM> to completely exit the axial bore <NUM> of the cam <NUM>, the interior drive bar <NUM> is biased forward (either self-biased or via the ejection spring <NUM>) and assists in pushing both the exterior drive bar <NUM> and torsion ring <NUM> out of the axial bore <NUM>; in <FIG>, one can see the interior drive bar <NUM> and the extended interior drive bar spring <NUM>. If the ejection spring <NUM> is present (either as a separate item or on the interior side of the interior drive bar <NUM>), this will tend to lead to the interior drive bar <NUM> also being ejected from the axial bore <NUM> to leave the empty blind hole <NUM>. The ejection spring <NUM> may also fall out or be frictionally, or otherwise, held within the blind hole <NUM>. Alternatively, if the interior drive bar <NUM> is biased by means of essentially an ejection spring <NUM> alone, then the interior drive bar <NUM> is likely to be fully pushed out of the axial bore <NUM> and will remove the torsion ring <NUM> and exterior drive bar <NUM> in the process. As shown in <FIG>, the entire clutch mechanism <NUM> has been, or would be, removed in this embodiment.

According to the embodiment shown in <FIG> and <FIG>, the swaged lip <NUM> at the end of the axial bore <NUM> will stop the torsion ring <NUM> from exiting the axial bore <NUM>. In such a case, the burglar will hopefully invest further time in trying to remove the torsion ring <NUM>, either in the mistaken belief that this will aid in the attack or because it is in the way. In <FIG> after the lock is vandalised, the torsion ring <NUM> is able to move axially within the first diameter region <NUM> and will leave the first state such that the bearing ball <NUM>, or other item, is no longer held in the pocket <NUM> by the step <NUM>. As the exterior cylinder lock <NUM> is removed, nothing is pushing the torsion ring <NUM> against the step <NUM> and the bearing ball <NUM> is able to leave the pocket <NUM>. The changed perspective view in <FIG> shows the open end of the pocket <NUM> with the bearing ball <NUM> still within the pocket <NUM> and slot <NUM> on the axial bore <NUM>. As will be appreciated, however, the arrangement shown in <FIG> and <FIG> is transitory, and the bearing ball <NUM> will readily fall out of the pocket <NUM> leaving behind the torsion ring <NUM> to freely rotate within the axial bore <NUM> but unable to transmit torque to the cam <NUM>.

Claim 1:
A cylinder lock actuator (<NUM>) comprising a first lock cylinder (<NUM>), a second lock cylinder (<NUM>) and a clutch mechanism (<NUM>), the clutch mechanism (<NUM>) being adapted to selectively engage either the first lock cylinder (<NUM>) or the second lock cylinder (<NUM>) with a cam (<NUM>) held rotatably in the cylinder lock actuator (<NUM>), wherein
the cam (<NUM>) is held in an axially moveable manner within the cylinder lock actuator (<NUM>), the cam (<NUM>) being normally located in a first axial position within the cylinder lock actuator (<NUM>) such that the clutch mechanism (<NUM>) can engage either of the first lock cylinder (<NUM>) or second lock cylinder (<NUM>) therewith, the cylinder lock actuator (<NUM>) further comprising biasing means which is adapted to axially move the cam (<NUM>) into a second position upon removal of the second lock cylinder (<NUM>), the cylinder lock actuator (<NUM>) comprising locking means which is adapted to constrain the cam (<NUM>) with respect to the first lock cylinder (<NUM>) when the cam is in the second position, and
the biasing means and locking means are adapted to operate independently of the state of the clutch mechanism (<NUM>);
wherein the biasing means and locking means are physically separate and separated from the clutch and/or physically isolated from the clutch mechanism (<NUM>).