Field of Invention

The present application relates to a cylinder lock actuator for use in a lock housing. In particular, the cylinder lock actuator provides an improved security Euro cylinder lock which is resistant to vandalism.

Background to the Invention

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 GB2565379B, 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 cyl inder in place. 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 application. The present application 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 1 can take no further part in operation of the cylinder lock actuator 1.

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.

Description of the Figures

Fig. 1: A side view of the cylinder lock actuator comprising a thumb turn as the interior lock actuator and a key operated lock cylinder as the exterior lock cylinder. Fig. 2: Cut-away version of Fig. 1 showing internal workings of cylinder lock actuator.

Fig. 3: Close-up view of the cylinder lock actuator of Fig. 2 without the key present in the exterior lock cylinder.

Fig. 4: Cut-away exploded view showing inner workings of interior lock cylinder, cam and exterior lock cylinder.

Fig. 5: Perspective view of vandalised lock according to Fig. 1.

Fig. 6: Cut-away view of vandalised cylinder lock actuator.

Fig. 7: Further example of a cylinder lock actuator showing cut-away view of cam after vandalism.

Fig. 8: Changed perspective view of Fig. 7.

Fig. 9: Perspective view of vandalised lock actuator showing partially cutaway cam and effects of vandalism.

In the following description, the cylinder lock actuator 1 is shown comprising a thumb turn 5 as the interior actuation mechanism and a key 6 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 1 may also be operated by means of a key 6, and the use of the thumb turn 5 is purely exemplary. In the following, specific elements which are shown of the thumb turn 5 and the interior lock cylinder 2 as integrating with the thumb turn 5 are not disclosed. The drawings relate to the co-pending application: GB2001363.7, which is held by the same Applicant and the teachings of which are explicitly incorporated herein in their entirety. The interaction between the thumb turn 5 and the interior lock cylinder 2, also known as the first lock cylinder 2, 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. 1 shows the general form of the cylinder lock actuator 1. The cylinder lock actuator 1 comprises the first or interior lock cylinder 2, which is provided on the left hand side of Fig. 1 and is operated by the thumb turn 5. The second or exterior lock cylinder 3 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 6. The cam 10 comprising the lug 11 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 2 and the exterior lock cylinder 3. It will be noted that the lug 11 fits within a lug gap 12 of the housing 4 of the cylinder lock actuator 1. The housing 4 surrounds the interior lock cylinder 2 and exterior lock cylinder 3, housing these in the cylinder lock actuator 1. The lug gap 12 consequently allows for the lug 11 to pass through the housing 4 in order to open and close the lock as required. The housing 4 comprises a weakness 7, typically and as shown in the figures in the form of a slot through the housing 4 in the region of the most exterior end of the cam 10. The weakness 7 is so located that upon vandalism of the cylinder lock actuator 2, the entire exterior lock cylinder 3 and the part of the housing 4 housing the exterior lock cylinder 3 will be snapped off and removed from the cylinder lock actuator 1. The perspective view shown in Fig. 5 of the cylinder lock actuator 1 shows one possible state of the cylinder lock actuator 1 after it has been vandalised; the manner in which elements within the cam 10 are affected by vandalism is quasirandom, so it is not guaranteed what parts will remain within the cam 10. As will be seen in the cut-away images of Figs. 2, 3 and 6, the region of the housing 4 surrounding the lug gap 12 can further comprise a strengthening block which provides improved rigidity to this part of the housing 4. 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. 2, the cylinder lock actuator 1 and the operation thereof can be seen in more detail. The key 6 is shown inserted within the keyway of the exterior lock cylinder 3, such that the spring-loaded split pins are appropriately aligned and the exterior cylinder lock actuator 3 could be rotated by rotating the key 6. This exterior lock cylinder 3 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 2 comprising the thumb turn 5 as shown in Fig. 2 is a specific thumb turn 5 operating for the interior lock cylinder 2. The specific operation allowing the thumb turn 5 to take over control of the interior lock cylinder 2 such that rotation of the thumb turn 5 is translated into rotation of the interior lock cylinder 2 is described elsewhere, in particular co-pending application GB2001363.7. 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 2 to either stop or allow rotation of the interior lock cylinder 2 within the housing 4 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 2 making up the present invention.

As shown in Fig. 2, the cam 10 is generally cylindrical in nature and comprises an axial bore 17 along its entire length. The axial bore 17 extends from the interior end of the cam 10 to the exterior end of the cam 10, as viewed when in the door, and comprises a clutch mechanism 13 therein. The clutch mechanism 13 is configured so as to allow preferential control of rotation of the cam 10 by the interior lock cylinder 2 or the exterior lock cylinder 3. The clutch mechanism 13 provides means for either of the interior lock cylinder 2 or the exterior lock cylinder 3 to take control over the cam 10, such that rotation of the relevant lock cylinder leads to rotation of the cam 10 to lock and unlock the lock. As shown in Fig. 2, the clutch mechanism 13 may further comprise a torsion ring 14 which is a generally circular, ring-like item positioned within the axial bore 17 of the cam 10. The torsion ring 14 is so configured that it is within the cylinder lock actuator 1 prior to it being vandalised, in such a state that rotation of the torsion ring 14 will lead to rotation of the cam 10. This first state of the torsion ring 14 is shown in Figs. 2 and 3 as being held within the axial bore 17 of the cam 10 by means of the exterior lock cylinder 3. The exterior lock cylinder 3 is so constructed that the end of the exterior lock cylinder 3 which is in the region of the cam 10, fits within the axial bore 17 of the cam 10 to such an extent that it holds the torsion ring 14 in the first state within the cam 10. As will be described later, removal of the exterior lock cylinder 3 after vandalism of the cylinder lock actuator 1 results in nothing physically holding the torsion ring 14 in the first state within the cam 10, and the torsion ring 14 is thus free to move axially along the axial bore 17 of the cam 10.

After the cylinder lock actuator 1 is vandalised, such that the exterior lock cylinder 3 is removed, the torsion ring 14 may leave the first state and enter a second state. In the second state, the torsion ring 14 is no longer held at a particular axial position within the axial bore 17 by the exterior lock cylinder 3 and further rotation of the torsion ring 14 will not lead to rotation of the cam 10. In some embodiments, as shown in Fig. 6 for example, the torsion ring 14 will be completely free to be removed from the axial bore 17 of the cam 10. In other embodiments, for example as shown in Figs. 7 to 9, the torsion ring 14 is held within the axial bore 17 of the cam 10. Figs. 7 to 9 shows the torsion ring 14 held within the axial bore 17 by means of a swaged lip 18, such that the torsion ring 14 is able to move axially within the axial bore 17 of the cam 10, however it is now in a second state such that the torsion ring 14 is able to rotate but will not transmit torque from this rotation through to the cam 10. Allowing the torsion ring 14 to stay within the axial bore of the cam 10 provides a physical mechanism which thwarts a burglar's attempts to gain complete access to the interior of the cam 10. The freely rotatable torsion ring 14 as shown in Fig. 9, for example, minimises the possible angles at which the burglar can insert tools within the axial bore 17 of the cam 10, whilst also providing a freely rotatable element which has no mechanism of transferring torque or any other forces to the cam 10. This, at the very least, will inconvenience the burglar in trying to damage the cylinder lock actuator 1 further, and will further cause the burglar to spend extra time and effort trying to further vandalise the cylinder lock actuator 1 thereby increasing the chances of discovery.

The clutch mechanism 13 further comprises an interior drive bar 15 and an exterior drive bar 16. The use of drive bars 15, 16 in clutch mechanisms is well- known, the specific interaction of the interior drive bar 15 and exterior drive bar 16 with the torsion ring 14 of the present invention, however, is not known. Each of the interior drive bar 15 and exterior drive bar 16 are provided with respective drive bar lugs 15a, 16a. The respective lugs 15a, 16a on the respective drive bars 15, 16 can best be seen in Fig. 4. The torsion ring 14 is provided with a torsion ring slot 14a in the interior circumferential surface of the torsion ring 14, 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 15, 16 is engaged with the torsion ring 14, such that rotation of the engaged drive bar 15, 16 will transmit the torque via the respective drive bar lug 15a, 16a to the torsion ring slot 14a. When the torsion ring 14 is held in the cylinder lock actuator 1 in the first state, rotation of the torsion ring 14 leads to rotation of the cam 10. Each of the drive bars 15, 16 is held within the axial bore 17 of the cam 10 in an axially moveable manner. The drive bars 15, 16 can consequently be moved axially within the axial bore 17, in Fig. 2 this is from left to right in the figure. Whichever of the drive bars 15, 16 is engaged with the torsion ring 14, leads to rotation of that drive bar rotating the torsion ring 14 and consequently the cam 10. In Fig. 2, because the key 6 is located within the exterior lock cylinder 3, the cylinder lock actuator 1 is configured such that the key 6 pushes the exterior drive bar 16 further within the axial bore 17 of the cam 10, thus ensuring that the exterior drive bar 16 is engaged with the torsion ring 14; this engagement meaning that the exterior drive bar lug 16a is located within the torsion ring slot 14a. With the exterior drive bar 16 of the clutch mechanism 13 engaged within the torsion ring 14, rotation of the key 6 will lead to the exterior lock cyli nder 3 rotating and the rotation of this is transmitted to the exterior drive bar 16. The exterior drive bar 16 is held within the exterior lock cylinder 3 in an axially moveable manner, but in a rotationally fixed manner. The exterior drive bar 16 is not able to rotate with respect to the exterior lock cylinder 3, and rotation of the exterior lock cylinder 3 leads to rotation of the exterior drive bar 16. In an analogous manner, the interior drive bar 15 is held in an axially moveable and rotationally fixed manner within the interior lock cylinder 2. This configuration means that the interior drive bar 15 may move axially within the interior lock cylinder 2 and axial bore 17 of the cam, but cannot rotate with respect to the interior lock cylinder 2. Rotation of the interior lock cylinder 2 leads to rotation of the interior drive bar 15 - which will be transmitted to the cam 10 when the interior drive bar 15 is engaged with the torsion ring 14.

The cylinder lock actuator 1 further comprises a mechanism of fixing the rotation of the cam with respect to the interior lock cylinder 2. This is shown in Figs. 2, 3 and 4 in particular and will be discussed in greater detail below. The mechanism of attaching the cam 10 to the interior lock cylinder 2 after lock vandalism and removal of the exterior lock cylinder 3 according to the present invention, may utilise an embodiment of an interior drive bar 15 within the clutch mechanism 13 as will be described in detail below in relation to Figs. 3 and 4. The interior drive bar 15 as discussed in relation to Figs. 3 and 4 below is one embodiment which interacts with the torsion ring 14; the torsion ring 14 can, however, be employed with known drive bar mechanisms to increase the security of any such cylinder lock actuator 1. In describing such general applications of the torsion ring 14, the interaction of the clutch mechanism 13 will firstly be described in general terms to be applied to any cylinder lock actuator 1.

In a known cylinder lock actuator 1, the mechanism described above by which the exterior drive bar 16 is pushed into alignment with the torsion ring 14 can be used with the interior lock cylinder 2. If the interior lock cylinder 2 is so structured that the thumb turn 5 or interior key operated lock cylinder were to provide a pushing force to axially move the interior drive bar 15 into engagement with the torsion ring 14, the interior drive bar 15, by means of the interior drive bar lug 15a engaging with the torsion ring slot 14a, would control rotation of the torsion ring 14. In this manner, whichever of the interior lock cylinder 2 or exterior lock cylinder 3 controls the clutch mechanism 13, such that the relevant drive bar 15, 16 is engaged with the torsion ring 14, the rotation of the lock cylinder in control of the clutch mechanism 13 causes rotation of the cam 10 and the lock to be locked or unlocked. It will further be appreciated that in such a lock cylinder actuator 1, which is not shown in any of the Figures, the removal of the exterior lock cylinder 3 as described above with regard to Figs. 5 to 9, would remove the exterior lock cylinder 3 as well as the exterior drive bar 16. As already disclosed, removal of the exterior lock cylinder 3 removes the physical urging of the torsion ring 14 into the first state where torque applied to the torsion ring 14 is further applied to the cam 10. Removal of the exterior lock cylinder 3 allows the torsion ring 14 to axially move along the axial bore 17 of the cam 16, as described above, and further rotation of the torsion ring 14 does not transfer torque to the cam 16, as the torsion ring 14 would have left said first state. As shown in Fig. 6, the torsion ring 14 may simply fall out of the axial bore 17 of such a cylinder lock actuator 1, or the torsion ring 14 may be held within the axial bore 17 of the cam 10 by means of the swaged lip 18, as shown in Fig. 7. In each of Figs. 6 and 7, the specific interior lock cylinder 2 as shown in said Figures, could simply be replaced with a copy of the exterior lock cylinder 3 as shown in Fig. 2, in such a case the clutch mechanism 13 as described above could be appropriately used with any cylinder lock actuator 1. The particular feature of the torsion ring 14 being held within the axial bore 17 is, therefore, not limited to the use with the further aspects of the cylinder lock actuator 1 described herein. The clutch mechanism 13, and in particular the torsion ring 14, of the present disclosure may therefore be used with any cylinder lock actuator 1 and provides the further benefit, when the torsion ring 14 remains within the axial bore 17 of the cam 10, 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 3. The torsion ring 14 is, therefore, a separate invention in its own right and can be used in other known cylinder lock actuators 1.

As has been discussed above, the torsion ring 14 has a first state in which the rotation of the torsion ring 14 is transmitted to rotate the cam 10. A second state of the torsion ring 14 exists in which the rotation of the torsion ring 14 within the axial bore 17 of the cam 10 will not lead to any torque being transmitted to the cam 10, such that the torsion ring 14 can rotate freely. As also described above, either the torsion ring 14 will be easily removable from the axial bore 17 of the cam 10, or the torsion ring 14 can be held within the actual bore 17 of the cam 10 by means of the swaged lip 18. In order to allow the torsion ring 14 to rotate freely without transmitting torque to the cam 10, the torsion ring 14 can be provided with an extension which interacts with an element within the axial bore 17 of the cam 10, such that the relative rotation between the torque ring 14 and cam 10 is not possible. The extension on the torsion ring 14 can take a number of different forms, the Figures showing one particular option thereof. By providing a pocket 25 on the outer circumferential side of the torsion ring 14, as seen in Fig. 7, a removable element can be located therein such that the removable element extends beyond the outer circumference of the torsion ring 14 to create the appropriate extension. Fig. 7 shows the extension being in the form of a bearing ball 24, however this is by way of example only. It would be appreciated that a bearing ball 24 is easy to manufacture or obtain from suppliers, and can readily be integrated into the cylinder lock actuator 1. Alternatively, the bearing ball 24 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 25 and beyond the outer circumference of the torsion ring 14. A slot 23 may be provided on the interior of the axial bore 17, as shown in Fig. 4, slot 23 allowing for the torsion ring 14 to slide into the axial bore 17 with bearing ball 24, or equivalent, held within the pocket 25. With the ball nearing 24 within the slot 23, it will be appreciated that the bearing ball 24 will transmit any torque applied to the torsion ring 14 via the side of the pocket 25 to the slot 23 on the interior of the axial bore 17 of the cam 10.

The end of the axial bore 17 in the cam 10 which is on the exterior side of the cylinder lock actuator 1, is provided with a region of a first diameter. This first diameter section 26, seen in Fig. 4, has a diameter which allows the torsion ring 14 to enter into the axial bore 17 of the cam 10 and without presence of the bearing ball 24, will allow for the torsion ring 14 to freely rotate without transmitting torque to the cam 10. If, however, the bearing ball 24 is present and within the pocket 25 of the torsion ring 14, when this assembly is positioned within the first diameter section 26 of the axial bore 17, rotation of the torsion ring 14 will transfer the torque through the bearing ball 24 to the slot 23 of the axial bore 17 as described above. The first diameter section 26 extends a distance within the axial bore 17 to a step 27 which signals the start of a second diameter section 28 of the axial bore 17. It is preferred that a straight sided step 27 is provided, as this is straightforward to manufacture and provides a definite stop to the torsion ring 14 entering further into the axial bore 17 of the cam 10. The interior diameter of the second diameter section 28 is smaller than the outer diameter of the torsion ring 14, thus meaning that the torsion ring 14 can only extend into the axial bore 17 in the region of the first diameter section 26. When the bearing ball 24 is in the pocket 25 of the torsion ring 14, the torsion ring 14 can be positioned within the first diameter section 26 such that the bearing ball 24 is within the slot 23 and the bearing ball 24 also rests against the step 27. The bearing ball 24 is removable from the pocket 25, thus meaning that the step 27 holds the bearing ball 24 within the pocket 25. Positioning the torsion ring 14 with the bearing ball 24 in the pocket 25 fully within the first diameter section 26, such that the bearing ball 24 is held within the pocket 25 by means of the step 27, is the first state of the torsion ring 14. In this state, rotation applied to the torsion ring 14 will ensure that the torque is transmitted via the bearing ball 24 through to the cam 10. As the bearing ball 24 is held within the pocket 25 by the step 27, or even pushed within the pocket 25, the torsion ring 24 will always be able to transmit torque to the cam 10 and the torsion ring 14 is maintained in the first state.

It will be appreciated that the presence of the exterior lock cylinder 3 ensures that the torsion ring 14 is pushed up to the full extent of the first diameter section 26, such that the bearing ball 24 is held within the pocket 25. The innermost end of the exterior lock cylinder 3 is so sized that it will fit within the first diameter section 26: that is, the external diameter of at least the end of the exterior lock cylinder 3 is smaller than the inner diameter of the first diameter section 26. Ideally, the second diameter section 28 has an interior diameter which is smaller than the exterior diameter of the exterior lock cylinder 3. The presence of the exterior lock cylinder 3 ensures that the torsion ring 14 remains in the first state, that is the torsion ring 14 remains fully abutting the step 27 such that the bearing ball 24 remains within the pocket 25. It will be appreciated, however, that once the lock is vandalised and the exterior lock cylinder 3 is removed, there is nothing holding the torsion ring 14 in a fully engaged manner in the first diameter section 26 and the torsion ring 14 is free to move axially along the axial bore 17 and away from the step 27. Once the torsion ring 14 is not held in place by the exterior lock cylinder 3, and can move away from the step 27, nothing holds the bearing ball 24 within the pocket 25 such that this can then fall out of the pocket 25 and slot 23. Once the bearing ball 24 has fallen out of the pocket 25 and slot 23, there is nothing which is present to transmit the torque from the torsion ring 14 through to the cam 10, and the torsion ring 14 is in a second state. The second state is defined as any state in which rotation of the torsion ring 14 does not lead to rotation of the cam 10. As a further matter, the removal of the exterior lock cylinder 3 means that there is no longer any element physically holding the torsion ring 14 within the cam 10: this further means that the torsion ring 14 is free to be removed and may simply fall out, or be pushed out by other elements within the cam 10, after removal of the exterior lock cylinder 3.

Whilst the embodiment above shows the bearing ball 24 being present in the pocket 25 on the external surface of the torsion ring 14 and within slot 23 along the inner circumferential surface of the first diameter section 26, this is by way of example only. It would also be possible to provide an indent on the surface of the step 27, the indent aligning with a removable protrusion extending axially from the rear face of the torsion ring 14 into said indent. Instead of the bearing ball 24 extending radially outward from the outer circumferential surface of the torsion ring 14, the bearing ball 24, or any other appropriate item, could be held in a removable manner in a pocket in the rear face of the torsion ring 14 and in alignment with the indent on the step 27 within the cam 10. Once again, the torsion ring 14 will be held in the first state, that is the extension being held within the indent on the step 27, by the presence of the exterior lock cylinder 3. Removal of the exterior lock cylinder 3 would allow for the torsion ring 14 to move away from the step 27, such that the bearing ball 24, or other appropriate element, would fall out of the pocket in the rear face of the torsion ring 14 and out of the indent in the step 27. This would transfer the torsion ring 14 into the second state, where the torsion ring 14 would be able to rotate freely in the axial bore 17 of the cam 10 without transmitting torque through to the cam 10.

A further possibility for defining the torsion ring 14 is that the extension in the outer circumferential surface of the torsion ring 14 or in the rear face of the torsion ring 14 in the second example given above, is not removable. In such a scenario, removal of the exterior lock cylinder 3 after vandalism allows the torsion ring to move axially along the axial bore 17 and to fall out of the axial bore 17 as shown in Fig. 6, thus taking the permanent extension with it and out of the slot 23 in the axial bore 17. Alternatively, the forward facing extension from the rear face of the torsion ring 14 would be able to move out of alignment with the indent in the step 27, such that the torsion ring 14 would then be free to rotate within the first diameter section 26 of the axial bore 17. In the case where the extension is radially protruding from the outer circumferential surface of the torsion ring 14 and is not removable, the torsion ring 14 would not be able to freely rotate within the axial bore 17, as the extension would be in the slot 23. However, the torsion ring 14 could easily fall out of the axial bore 17 of the cam 10 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 2 can most clearly be seen in Figs. 4 and 9 and relate to fixing the cam 10 to the interior lock cylinder 2. In particular, the end of the interior lock cylinder 2 which is held within the axial bore 17 of the cam 10, has a diameter which is smaller than the interior diameter of the second diameter section 28. The end of the interior lock cylinder 2 also comprises a blind hole 22 or indent, into which the interior drive bar 15 can slidably engage. The interior drive bar 15 is able to axially move within the blind hole 22 of the interior lock cylinder 2, however the interior drive bar 15 is not able to rotate with respect to the interior lock cylinder 2 and is held within the blind hole 22 in a manner that does not permit relative rotation. The interior drive bar 15 can move in and out of complete engagement with the blind hole 22, but cannot rotate with respect thereto. By configuring the interior drive bar 15 so that it cannot rotate with respect to the interior lock cylinder 2, ensures that rotation of the interior lock cylinder 2 leads to rotation of the interior drive bar 15. When the interior drive bar 15 is engaged with the torsion ring 14, rotation of the interior lock cylinder 2 thus leads to rotation of the cam 10. The interior drive bar 15 preferably comprises two interacting elements. The first part of the interior drive bar 15 comprises a generally cylindrically extending form which comprises the drive bar lug 15a. The second part of the interior drive bar 15 comprises a drive bar fixed part 20 and a drive bar spring 19. The drive bar spring 19 can be seen in Figs. 3 and 4, this being located between the drive bar fixed part 20 and the cylindrical part of the drive bar 15. The drive bar spring 19 is generally affixed to the drive bar fixed part 20, and provides a repulsive force between the drive bar fixed part 20 and the cylindrical part of the interior drive bar 15. The effect of the essentially spring loaded interior drive bar 15, can best be seen in Fig. 3. As can be seen in Fig. 3, the lock prior to vandalism is one in which the interior drive bar 15 is spring-loaded into engagement with the torsion ring 14. Indeed, the present cylinder lock actuator 1 is one in which the interior lock cylinder 2 is generally biased to control the rotation of the torsion ring 14. Only when the key 6 is inserted into the exterior lock cylinder 3, as shown in Fig. 2, will the exterior drive bar 16 push against the drive bar spring 19 to disengage the interior drive bar 15 from the torsion ring 14. Removal of the key 6 means that the drive bar spring 19 pushes the cylindrical part of the interior drive bar 15 against the exterior drive bar 16, pushing the exterior drive bar 16 out of engagement with the torsion ring 14 and ensuring that the interior drive bar 15 is in engagement with the torsion bar 14. Basically, the natural state of the cylinder lock actuator 1 without the presence of the key 6 fully inserted, is one in which the interior lock cylinder 2 is always engaged to control the rotation of the cam 10. As can be seen in Fig. 3, the blind hole 22 is structured to fully hold the interior drive bar fixed part 20 at the end of the blind hole 22, allowing the drive bar spring 19 to extend and push the cylindrical part of the interior drive bar 15 into engagement with the torsion ring 14. In this way, it is clear that no part of the thumb turn 5 is needed to push the interior drive bar into engagement with the torsion ring 14, as it is only the presence of the key 6 in the exterior lock cylinder 3 which removes rotational control of the cam 10 from the interior lock cylinder 2. If the thumb turn 5 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 2 would not affect the engaged position of the interior drive bar 15 with the torsion ring 14. As will be appreciated, after the lock is vandalised and the torsion ring 14 is moved out of the first state, or indeed is removed from the axial bore 17 of the cam 10 completely, the interior drive bar 15 will simply be held within the blind hole 22, or may even itself exit the axial bore 17 of the cam 10. Fixing the drive bar fixed part 20 in a permanent manner within the blind hole 22 is possible, but is not necessary and in fact may even be undesirable. Allowing the entirety of the interior drive bar 15 to be removable from the axial bore 17 means that a burglar would see only the interior of the cam 10 and the blind hole 22 of the interior lock cylinder 2, providing nothing to further attack.

As can be seen in Fig. 4, it is also possible to provide an ejection spring 21 within the blind hole 22, in order to promote that all elements of the clutch mechanism 13 are expelled or ejected from the axial bore 17 of the cam 10 when the lock is vandalised. The ejection spring 21 as shown in Fig. 4 has the structure of a cone spring, wherein this cone spring would be fully compressed between the interior drive bar fixed part 20 and the end of the blind hole 22 when the cylinder lock actuator 1 is assembled and prior to vandalising. It will be appreciated that the ejection spring 22 will provide a further force on the interior drive bar fixed part 20, pushing this further outward and further ensuring engagement of the interior drive bar 15 with the torsion ring 14. Upon removal of the exterior lock cylinder 3 by vandalism, the exterior drive bar 16 will fall out of the axial bore of the cam 10, and the torsion ring 14 will leave the first state and will either be ejected or left in a rotationally free manner within the first diameter section 26 of the axial bore 17 - i.e. it would enter the second state. The interior drive bar 15 will then be forced out of the axial bore 17 by the force of the ejection spring 21, thus facilitating the expulsion of both drive bars 15, 16 from the axial bore 17. If the axial bore 17 does not have the swaged lip 18, it is clear the ejection spring 21 would also provide a force on the torsion ring 14 to expel this from the axial bore 17. The ejection spring 21 need not be a cone spring, but could be any compression spring, and advantageously the ejection spring 21 could be held within the blind hole 22 of the interior lock cylinder 2. If the ejection spring 21 is fixed within the blind hole 22, either frictionally or by welding or by adhesive or by moulding together, or any other permanent mechanism suitable for keeping the ejection spring 21 within the blind hole 22, after the lock is vandalised the spring will be located and kept within the axial bore 17 of the cam 10. The presence of the fixed ejection spring 21, 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 1. Should the burglar try to use a drill to gain further access to elements of the cylinder lock actuator 1, the ejection spring 21 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 1, and would certainly give greater opportunity for the burglar to be seen duri ng the attempt to enter the building.

Rather than having a separate ejection spring 21 acting on the interior drive bar fixed part 20, another embodiment is for the interior drive bar fixed part 20 to comprise a spring itself acting against the end of the blind hole 22. Such a design would prove a spring force that both leads to the interior drive bar 15 being usually engaged with the torsion ring 14 and also being strong enough to eject the interior drive bar 15, torsion ring 14 and exterior drive bar 16 if the lock is vandalised. Such a design for the interior drive bar 15 is not shown in the figures. This integrated ejection interior drive bar 15 would not leave the spring within the blind hole 22 of the interior lock cylinder 2, but would assist in ensuring the removal of the clutch mechanism 13 with or without leaving the torsion ring 14 in the axial bore 17. It is also possible to provide the interior drive bar 15 with the cylindrical drive bar element and a drive bar spring 19 alone. The drive bar spring 19 would act against the end of the blind hole 22 to push the cylindrical part of the interior drive bar 15 into engagement with the torsion ring 14, and upon the lock being vandalised would also assist in ejecting the clutch mechanism 13 out of the axial bore 17 of the cam 10.

Further aspects of the security features of the current cylinder lock actuator 1 can be appreciated when comparing Fig. 1 and Fig. 5. In Fig. 1, prior to the cylinder lock actuator 1 being vandalised, the cam 10 can be controlled via the clutch mechanism 13. The cam 10 rotates independently of each of the interior lock cylinder 2 and exterior lock cylinder 3, when the respective lock cylinder 2, 3 is not engaged with the clutch mechanism 13. After the lock has been vandalised and the exterior lock cylinder 3 is removed, as shown in Fig. 5, the cylinder lock actuator 1 enters a vandalised condition where the cam 10 is permanently engaged with the interior lock cylinder 2. In this vandalised state, the cam 10 is locked to the interior lock cylinder 2 and the cam 16 cannot rotate with respect to the interior lock cylinder 2. Crucially, the movement of the cam 10 is irrespective of any aspect of the clutch mechanism 3, is achieved by entirely independent means and nothing held within the clutch mechanism triggers or influences the locking of the cam 10 to the interior lock cylinder 2. When comparing Figs. 1 and 5, the cam 2 has a locking slot 31 therein. Whilst the locking slot 31 is shown extending through the wall of the cam 10, this is by way of example only. The locking slot 31 may, in fact, be an indent on the interior side of the axial bore 17 of the cam 10, providing a blind hole or indent which does not pass through the side wall of the cam 10. The number of locking slots 31 is not limited, and it is contemplated that two locking slots 31 will be present within the cam 10, generally one on either side of the cylinder lock actuator 1. The means of fixing the cam 10 to the interior locking cylinder 2 is by means of one or more locking pins 30. The locking pins 30 are held within the interior lock cylinder 2 and are preferably biased out of the interior locking cylinder 2. As can be seen in the exploded view of Fig. 4, the interior lock cylinder 2 comprises a locking pin hole or bore 34 in a position behind the blind hole 22. This position is at a location more interior and away from the cam 10 than the blind hole 22, and crucially the locking pin hole 34 is an entirely separate hole or slot in the interior lock cylinder 2 from the blind hole 22. This means that the locking pin hole 34 and locking means for holding the cam 10 in rotational alignment with the interior lock cylinder 2, are completely separate from the blind hole 22 and any elements of the clutch mechanism 13. This has the further benefit that the mechanism for fixing the cam 10 to the interior lock cylinder 2 after vandalism is not accessible through the axial bore 17 of the cam, as the locking pin hole 34 is positioned separate from the blind hole 22 holding the clutch mechanism 13 and has the material making up the interior lock cylinder 2 to protect it.

The locking pin hole 34 can either be a single blind hole in which a single locking pin 30 is located, or as shown in Fig. 4, the locking pin hole 34 can be a through hole passing through from one side of the interior lock cylinder 2 to the other side thereof. In this scenario, two locking pins 30 are located within the locking pin hole 34 and a single locking pin spring 33 is positioned there-between to bias the locking pins 30 out of the locking pin hole 34. In the scenario where a single blind hole is present for the locking pin hole 34, the locking pin spring 33 would be positioned between the end of the locking pin blind hole and the locking pin 30 to bias the locking pin 30 out of the locking pin blind hole.

As can be seen in Fig. 1: prior to the cylinder lock actuator 1 being vandalised, the cam 10 is so positioned that the locking slot 31 blocks the locking pin 30 from exiting the locking pin hole 34. In this arrangement, the end of the locking pin 30 is pushed against the interior surface of the axial bore 17, but does not stop rotation of the cam 10 and normal operation of the locking pin actuator 1. When the cylinder lock actuator 1 is vandalised, however, the cam 10 is located in an orientation such that the locking slot 31 now aligns with the position of the locking pin 30, and the locking pin 30 is biased into the locking slot 31. The same would occur if the locking slot does not extend through the surface of the cam 10, but rather forms an indent on the interior surface thereof. Once the locking pin 30, or locking pins in the example shown in Fig. 4, have extended into the aligned respective locking slot or locking slots 31, the cam 10 is then mechanically connected with the interior lock cylinder 1 and cannot rotate freely without rotation of the interior locking cylinder 2. As will be appreciated, the interior lock cylinder 2 can only be rotated by rotating the thumb turn 5 or, if the thumb turn 5 is replaced by a key cylinder, by introducing a key into the interior lock cylinder 2, properly aligning the key and allowing rotation of the interior lock cylinder 2 which will also rotate the affixed cam 10. As the interior lock cylinder 2 either in the form of the thumb turn 5 or in the form of a key operated lock cylinder cannot be operated by rotating the cam 10, the cam 10 is locked in rotational alignment with the interior lock cylinder 2 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 10 is rotatably fixed with respect to the interior lock cylinder 2 after lock vandalism, the burglar on the exterior of the door cannot rotate the cam 10 because the interior lock cylinder 2 blocks rotation thereof. Of course, a person on the inside of the door can engage the interior lock cylinder 2 and rotate this, thus leading to rotation of the cam 10; 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 1 of the present disclosure.

It should be noted that the locking slot 31 is shown as an extended slot in the figures, however the locking slot 31 could be simply a round hole which accommodates the size of the locking pin 30 to allow the locking pin 30 to extend into the locking slot 31, even when circular, thus ensuring the cam 10 and the interior lock cylinder 2 cannot freely rotate independently upon lock vandalism . The use of the locking slot 31 allows for the locking pin 30 to engage with the locking slot 31 at a greater number of relative angles between the locking pin 30 and locking slot 31, thus improving the locking together of these two elements - the limited relative rotation which the locking slot 31 then affords is not, however, enough for the burglar to operate the cam 10. Furthermore, the locking pin 30 can have a structure such that the outer end has a narrower diameter which will fit within the locking slot 31, the inner end of the locking pin 30 having a larger diameter which will not pass into the locking slot 31. In this way, when the locking pin 30 is biased into engagement with the locking slot 31, it cannot pass all the way through the locking slot 31 and will therefore properly function to hold the cam 10 rotationally aligned with the interior lock cylinder 2.

In order that the cam 10 can be located such that the locking slot 31 aligns with the locking pin 30, the cam 10 is held on the outer surface of the interior lock cylinder 2 in an axially moveable manner. As already mentioned, the outer diameter of the end of the interior lock cylinder 2 which is located within the axial bore 17, is smaller than the second diameter section 28. This allows for the cam 10 to not only rotate around the interior lock cylinder when the exterior lock cylinder 3 is engaged via the clutch mechanism 13, but also allows the cam 10 to slide axially along the outer surface of the interior lock cylinder 1 after the cylinder lock actuator 1 has been vandalised. Once the cylinder lock actuator 1 has been vandalised, there is nothing holding the cam 10 in axial alignment with the interior lock cylinder 2, thus meaning that the cam 10 is free to move axially along the outer surface of the interior lock cylinder 2. If the cam 10 moves axially away from the interior lock cylinder 2, it is then clear that at some point the locking slot 31 will align with the locking pin 30 and the locking pin 30 will be able to engage with the locking slot and stop further axial movement whilst also linking the cam 10 and the interior lock cylinder 2 to stop relative rotation between the two, aside from that which the locking slot 31 might afford .

Rather than leaving to chance the burglar pulling the cam 10 forward and thereby aligning the locking slot 31 with the locking pin 30, the cylinder lock actuator 1 of the invention comprises means which bias the cam 10 away from the interior lock actuator 2. The principle of operation is that upon removal of the exterior lock cylinder 3 by vandalism, the biasing means act to push the cam 10 away from the interior lock actuator 2 to the extent that the locking slot 31 will align with the locking pin 30 and the two will engage. The biasing means can be seen in Figs. 4 and 5 and in the embodiment shown take the form of a cam spring 35, 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 10. The cam spring 35 is so aligned and positioned that it acts to push the cam 10 away from the interior lock cylinder 2. When comparing the position of the cam 10 in Figs. 3 and 6, it will be noted that the cam 10 in Fig. 3, the non- vandalised cylinder lock actuator 1 as shown in Fig. 1, is positioned more closely to the interior lock cylinder 2. After the cylinder lock actuator 1 is vandalised, the cam 10 is free to move axially along the outer surface of the interior lock cylinder 2, and is biased and pushed by means of the cam spring 35, until the locking slot 31 aligns with the locking pin 30 and the locking pin 30 holds the cam 10 with the interior lock cylinder 2. The cam spring 35, therefore, provides a completely isolated and independent means of pushing the cam 10 into locking alignment through the use of the locking slot 31 and locking pin 30.

As shown in Fig. 3, the exterior surface of the interior lock cylinder 2 has a first end with a first diameter which will fit within the second diameter section 28 of the axial bore 17, which extends far enough along the interior lock cylinder 2 to allow this to fully extend into the axial bore 17 and position the interior drive bar 15 for alignment with the torsion ring 14. 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 36 in Fig. 6. The spring step 36 is the surface against which the cam spring 34 acts to push the cam 10 away from the interior lock cylinder 2. The cylinder lock actuator 1 functions by simply positioning the cam spring 35 between the interior end of the cam 10 and the cam step 36, and the cam spring 35 will then act to push the cam 10 into locking alignment by means of the locking slot 31 and locking pin 30. In order to properly hold the cam spring 35 in position, a spring pocket 37 can be formed on the interior end of the axial bore 17 of the cam 10. The spring pocket 37 is a region of increased diameter in the axial bore 17, wherein this will then house the cam spring 35. The cam spring 35 has an interior diameter which is greater than the diameter at the end of the first lock cylinder 2, so that the cam spring 35 can slide over the first interior lock cylinder 2. The diameter of the cam spring 35 is smaller than the diameter of the spring step 36, thus meaning that the cam spring 35 is only able to move along the smaller diameter end to the interior lock cylinder 2. The spring pocket 37 on the cam 10 has a diameter greater than the outer diameter of the cam spring 35, thus meaning that it can slot over the cam spring 35 and hold the cam spring 35 properly in position. In the pre-vandalised condition of the cylinder lock actuator 1 shown in Fig. 3, the cam spring 35 is fully compressed, once the lock is vandalised as shown in Fig. 6 the cam spring 35 can decompress slightly and push the cam 10 into locking alignment as shown in Fig. 5. As will be appreciated when comparing Figs. 3 and 6, if the cylinder lock actuator 1 is vandalised, the lug 11 will move within the lug slot 12. When the cam 10 is biased into the locked orientation as shown in Fig. 6, the lug 11 will be pushed against the exterior side of the lug gap 12. Obviously, if the lug 11 were to be held in the cam 10 in a non-moveable manner, this could stop the cam 10 from extending forward sufficiently to allow the cam 10 to lock to the interior lock cylinder 2. To this end, the lug 11 is held in an axially moveable manner within the cam 10, such that when the cam 10 is pushed forward by the cam spring 35 into a locked orientation, the lug 10 is moved axially with respect to the cam 10 so that it does not strike the housing 4 and rotation of the cam 10 is still possible. As shown in Fig. 4, the lug 11 is provided with a lug bar 40, this lug bar 40 extending through a lug bar hole 42 in the lug 11. The lug 11 is held on the lug bar 40 with the lug bar 40 passing through the lug bar hole 42, the lug 11 being able to slide along the lug bar 40. In this manner, the lug 11 is able to slide with respect to the cam 10 and will not block rotation of the cam 10 when the lock is vandalised and the cam 10 has moved away from the interior lock cylinder 2. In order to assist in moving the lug 11 and ensuring that the lug 11 does not impede rotation of the cam 10, one or more lug springs 41 can be located between the lug 11 and the cam 10 in order to bias the lug 11 with respect to the cam 10. It will be appreciated that the lug bar 40 is held within the cam 10 and an appropriate aperture is provided such that the upper part of the lug 11 can fit around the lug bar 40 within the cam 10 and move forward and backward along the lug bar 40 as required, and as the position of the cam 10 dictates. The lug springs 41 can be so designed as to bias the lug 11 into a location which will align with the lug gap 12 when the cylinder lock actuator 1 has not been vandalised. Movement of the lug 11 does not require a great amount of force, thus meaning that the lug springs 41, if present, need only be strong enough to effect alignment of the lug 11 within the lug gap 12. To this end, the force applied by the lug springs 41 onto the lug 11 is such that it will provide very little, if any, counter force to the movement of the cam 10 upon vandalism of the cylinder lock actuator 1 when the cam 11 strikes the side of the lug gap 12. Furthermore, in the case that the cylinder lock actuator 1 has been vandalised and the lug 11 is resting against the inner face of the lug gap 12 once the cam 10 has moved into its locked orientation, the pressure of the lug 11 against the lug gap 12 (or interior of the lock itself) caused by the force of the lug springs 41 does not impede operation of the cylinder lock actuator 1 by a user on the interior of the door. In this way, the functioning of the cylinder lock actuator 1 from the interior of the door is assured after it is vandalised, as is the safety of the user.

Looking at Fig. 2, this shows the non-vandalised state of the lock actuator 1 with the key 6 in the exterior lock cylinder 3. The key 6 pushes the interior drive bar into engagement with the torsion ring 14, such that rotation of the key 6 will rotate the interior drive bar 16 and through the torsion ring 14 will appropriately rotate the cam 10. Removal of the key 6 from the exterior lock cylinder 3 puts the cylinder lock actuator 1 into the position shown in Fig. 3. As seen in Fig. 3, the biased interior drive bar 15 is pushed into engagement with the torsion ring 14, such that the thumb turn 5 is able to operate the cylinder lock actuator 1 and rotation of the thumb turn 5 is transmitted through the interior drive bar 15 to the torsion ring 14 and the cam 10. As shown, the thumb turn 5 is always in control of the cylinder lock actuator 1 unless the key 6 is fully inserted into the exterior lock cylinder 3. If the thumb turn 5 were replaced by a key operated cylinder, the biased interior drive bar 15 would still always be in engagement with the torsion ring 14 unless the key 6 were placed in the exterior cylinder lock 3.

Upon vandalising the cylinder lock actuator 1, the exterior lock cylinder 3 is removed and the remaining parts may take the form as shown in Fig. 5; as will be appreciated from the above, it is possible for the interior drive bar 15 and/or the torsion ring 14 to remain within the cam 10 in a non-functional state. Once the exterior lock cylinder 3 has been removed this no longer holds the cam 10 in position against the cam spring 35 and the cam spring 35 pushes the cam 10 away from the interior lock cylinder 2, until the one or more locking slots 31 engages with the one or more respectively aligned locking pins 30. The locking pins 30 are then biased into the locking slot 31, whether this is the through slot as shown in the figures or an indent on the interior of the axial bore 17, the cam 10 is then held in a fixed manner with regard to the interior lock cylinder 2. Rotation of the cam 10 is then only possible by actuating the interior lock cylinder 2, either by means of the thumb turn 5 shown or the key if a key operated interior lock cylinder 2 is present. This means that the burglar is unable to rotate the cam 10, as it is locked properly to the interior lock cylinder 2, but a person on the interior side of the cylinder lock actuator 1 is able to lock and unlock the lock as normal. As shown in Fig. 6, if the design allows for the torsion ring 14 to completely exit the axial bore 17 of the cam 10, the interior drive bar 15 is biased forward (either self-biased or via the ejection spring 21) and assists in pushing both the exterior drive bar 16 and torsion ring 14 out of the axial bore 17; in Fig. 6, one can see the interior drive bar 15 and the extended interior drive bar spring 19. If the ejection spring 21 is present (either as a separate item or on the interior side of the interior drive bar 15), this will tend to lead to the interior drive bar 15 also being ejected from the axial bore 17 to leave the empty blind hole 22. The ejection spring 21 may also fall out or be frictionally, or otherwise, held within the blind hole 22. Alternatively, if the interior drive bar 15 is biased by means of essentially an ejection spring 21 alone, then the interior drive bar 15 is likely to be fully pushed out of the axial bore 17 and will remove the torsion ring 14 and exterior drive bar 16 in the process. As shown in Fig. 6, the entire clutch mechanism 13 has been, or would be, removed in this embodiment.

According to the embodiment shown in Figs. 7 and 8, the swaged lip 18 at the end of the axial bore 17 will stop the torsion ring 14 from exiting the axial bore 17. In such a case, the burglar will hopefully invest further time in trying to remove the torsion ring 14, either in the mistaken belief that this will aid in the attack or because it is in the way. In Fig. 7 after the lock is vandalised, the torsion ring 14 is able to move axially within the first diameter region 26 and will leave the first state such that the bearing ball 24, or other item, is no longer held in the pocket 25 by the step 27. As the exterior cylinder lock 3 is removed, nothing is pushing the torsion ring 14 against the step 27 and the bearing ball 24 is able to leave the pocket 25. The changed perspective view in Fig. 8 shows the open end of the pocket 25 with the bearing ball 24 still within the pocket 25 and slot 23 on the axial bore 17. As will be appreciated, however, the arrangement shown in Fig. 7 and 8 is transitory, and the bearing ball 24 will readily fall out of the pocket 25 leaving behind the torsion ring 14 to freely rotate within the axial bore 17 but unable to transmit torque to the cam 10.

Fig. 9 shows the state of the fully vandalised cylinder lock actuator 1. The exterior lock cylinder 3 has been removed, the external drive bar 16 has also been removed, the interior drive bar 15 has been ejected from the blind hole 22 and the cam spring 35 has extended and pushed the cam 10 into locked alignment by means of the locking pins 30. The torsion ring has generally been pushed forward to engage with the swaged lip 18, and in so doing the bearing ball 24 has fallen out and can no longer transmit torque through to the cam 10 and the torsion ring 14 is able to rotate freely and move axially between the swaged lip 18 and the step 27. The embodiment shown in Fig. 9 does not include the ejecting spring 21 as a separate item, rather the interior drive bar has been ejected by means of the drive bar spring 19. This is by way of example only, and the ejection spring 21 may be used in this Figure as described above. In the arrangement shown in Fig. 9, the cam 10 is fully locked to the interior lock cylinder 2, the torsion ring 14 is held within the axial bore 17 in both an axially and rotationally moveable manner, and the axial bore 17 is completely empty and the burglar would only see the end of the blind hole 22. In this manner, the burglar has no access to the completely physically separate locking pins 30, and cannot force rotation of the cam 10 as the cam 10 is mechanically connected to the interior cylinder lock 2. In this orientation, the person on the inside of the door can still fully operate the lock by means of the thumb turn 5, but the burglar is left with an empty cam 10 and nothing in which to operate the lock. Furthermore, the freely rotatable torsion ring 14 minimises the angle of attack which the burglar could make, and causes more difficulty in attacking the lock. Should the ejection spring 21 still be in place, this would make it more difficult for the burglar to then try and drill the end of the blind hole to try and gain access to the locking pins 30.