The present disclosure relates to a lock actuator for interacting with a lock on either a window or door. In particular, the lock actuator of the present disclosure comprises a thumbturn; the thumbturn is intended to be located on the interior side of the door or window which is to be locked.

Background:

For security purposes, it is common to provide a lock on doors and windows, this ensures that the operation and opening of the doors and windows can be limited to only desired users. Well-known locks comprise key operated cylinders, such that operation of the lock can only be achieved if the correct key is possessed. Inserting the key into the key operated cylinder will align the lock pins in the pin tumbler lock mechanism and allow the cylinder to rotate; this rotation will typically be transmitted to an interior portion of the lock, which will then operate the locking mechanism to selectively lock and unlock the door and/or window. The lock is typically provided within the door or window, and the lock will itself be actuated by means of a separate lock actuator which comprises the key operated cylinders.

It is often inconvenient for a user of a lock to require a key to operate both the exterior and interior of the lock. In such circumstances, the interior side of the lock may be provided by means of a thumbturn mechanism, the thumbturn mechanism allowing the user to readily open and close the lock without the need of having the correct key to hand. Evidently, in cases of emergency, it is extremely inconvenient and even dangerous for a person located on the interior side of the door or window to have to find the correct key to properly unlock the lock and escape. In such circumstances, the thumbturn mechanism interacting with the lock of the door is of particular benefit, significantly improving the safety for the user of the lock.

In many cases, the lock is integrated into the door or window at manufacture, and a lock actuator is a separate item which can be introduced into the lock to allow selective locking and unlocking of the lock. Many lock actuators are designed to combat vandalism. In an attempt to bypass the lock and gain access through the door or window, vandals try and remove sections of the lock actuator in the hopes of obtaining access to the interior of the lock and then gaining actuation of the lock itself. l This and other issues are addressed by the invention which includes a lock actuator comprising a housing having an interior and exterior side either side of a cam held rotatably in the lock actuator, the interior side comprising a thumbturn mechanism adapted to selectively engage with the cam, the thumbturn mechanism comprising: a core, at least a part of which is rotatably held within a central bore of the cam, the core comprising a central bore, a first end of the central bore of the core being adapted to hold a drive bar in a rotatably fixed but translationally free manner with respect to the core, the drive bar being biased into engagement with the cam and configured such that rotation of the core will rotate the cam via the drive bar; and locking means adapted to lock and unlock rotation of the core in the housing, the locking means configured to be in the normally locked configuration and to unlock rotation of the core with user operation of the thumbturn mechanism.

The present invention generally describes a lock actuator which on the exterior side is intended to be operated by a higher security mechanism, perhaps by means of a key operated cylinder, whilst on the interior side the actuator is operated by a thumbturn or other hand operated, non-key operated, means. The lock actuator is also designed to specifically break under attack, such that the exterior side will be selectively removed and the interior sections of the lock actuator will then lock together thus blocking rotation of the locking mechanism from the exterior of the door or window. The lock actuator is designed such that the locking mechanism is held in a normally rotationally locked state, the lock actuator only being unlocked by specific operation of either the exterior side cylinder or the interior thumbturn mechanism: other attempts to operate the lock actuator being blocked. To this end, removal of the exterior side cylinder will mean that the lock actuator cannot be operated from the outside. The lock actuator of the present disclosure also will allow that the interior side, thumbturn section of the lock actuator continues to work as normal, even after vandalism of the lock actuator. In this manner, the user of the lock can always open the lock and escape through the door or window, irrespective of whether the lock has been vandalized or otherwise.

The present invention will now be described by way of example with reference also to the accompanying drawings.

Description of the Figures:

Figure 1: perspective view of a lock actuator according to the present invention. Figure 2: partial cutaway of the lock actuator of the present invention.

Figure 3: cutaway showing interior operation of the lock actuator of the present invention.

Figure 4: cutaway perspective view of the lock actuator of the present invention.

Figure 5: close up cutaway view showing interior of the cam of the present invention.

Figure 6: partial cutaway view showing interaction of the thumbturn section of the lock actuator with the cam.

Figure 7: view showing presence of a guider to assist in smooth operation of the lock actuator.

Figure 8: close-up of the guider from Figure 7.

Detailed Description:

Figure 1 shows a perspective view of a lock actuator 1 according to the present invention. This is intended for use traversing a lock and comprises exterior and interior sides, 2 and 3 respectively that are accessible from the exterior and the interior sides of the door or window comprising the lock. On the left-hand side of the Figure, the exterior side 2 of the lock actuator 1 is shown in a non-limiting embodiment as a key operated cylinder other options, such as wafer lock mechanisms could be used. The principle of operation of the lock actuator 1 according to the present application, relates primarily to the operation of the interior side 3 of the lock actuator 1; this can be seen on the right-hand side of Figure 1. The portion of the lock actuator 1 which is to be used on the interior of the door or window, comprises a thumbturn mechanism 4, which is clearly seen in Figure 2. The lock actuator 1 of the present disclosure is primarily intended to fit within a door or window lock, not shown in the Figures, which will provide some degree of secure locking of the door or window to the surrounding frame.

As seen in Figure 1, the lock actuator 1 also comprises a cam 10 which is selectively rotated by either the key operated cylinder, or the thumbturn mechanism 4. As is known in the art, inserting a key into the key operated cylinder engages a core of the cylinder with the cam 10 and causes tumbler pins therein to align with a shear line of the cylinder to allow the core and thereby the cam 10 to rotate. In this manner, the user of the lock actuator 1 can cause interaction of the cam 10 with the door lock to open and close the locking mechanism. Rather than providing key operated cylinders on the inside and outside of the lock, thumbturn lock actuators 1 are also known in the art and allow a user to open and close the associated lock without the need of a key. Typically, pushing the thumbturn 7 into the interior side 2 of the actuator and rotating same engages the thumbturn 7 with the cam 10 and also causes rotation of the cam 10 to lock and unlock the lock.

As can further be seen in Figure 1, the casing of the lock actuator 1 of the present disclosure comprises a sacrificial cut 5 which is a predefined point of weakness of the lock actuator 1. This causes the casing to snap at this point of weakness so that the exterior side 2 of the lock actuator 1 falls away if the lock actuator 1 is vandalized thus making it more difficult for the vandal to force the lock. The sacrificial cut 5 is known in the art, however the lock actuator 1 of the present disclosure comprises additional specific vandalism protection as is described below. The lock actuator 1 is intended to break under vandalism at the sacrificial cut 5, then to lock rotation of the cam 10 within the lock actuator 1 which stops the vandal from being able to unlock the door itself after snapping the lock actuator 1. A further aspect of the present disclosure is, however, that the lock actuator 1 can still be operated as normal from the inside by means of the thumbturn mechanism 4. As can also be seen in Figure 1, the lock actuator 1 may further be provided with a reinforcing bar 6, positioned in the region of the cam 10 as a known weak spot in lock actuators 1.

As seen in Figures 1 and 2, the cam 10 is provided with a lever 11, which is in the form of an extension from the external surface of the cam 10. The lever 11 rotates with rotation of the cam 10, and it is lever 11 which will interact with the lock attached to the door or window. Operation of the cam 10 and lever 11 is standard in locks, and the lock actuator 1 of the present disclosure is thus able to interact with most standard locks provided in doors and windows. The lock actuator 1 is sized and shaped to fit within the normal fitments provided by a door lock, and in particular comprises a euro cylinder lock actuator with a casing of standard size and footprint.

When looking at the cutaway images of Figures 2 and 3, particular elements of the thumbturn mechanism 4 can be seen and highlighted. The thumbturn mechanism 4 provides the basis for the present application, and will be focused on primarily in the following. As will be clear to the reader, the lock actuator 1 of the present disclosure may be provided with any standard exterior security measure for limiting rotation of the cam 10 from the outside of the door, and the present disclosure is not limited by means of the key operated cylinder described in the Figures. Crucial aspects of the present disclosure relate to the security of the lock after vandalism of the lock actuator 1; importantly, that the cam 10 is locked from being rotated from the outside by means of elements in the thumbturn mechanism 4. This locking of the cam 10, means that the lock actuator 1 will not allow rotation of the cam 10 from the outside after vandalism, but will allow for rotation of the cam 10 from the inside by means of the thumbturn mechanism 4.

Looking at Figure 3, the operation of the cam 10 can be understood. The cam 10 comprises a central bore 11 into which further elements used for rotation of the cam 10 are provided. In Figures 3 and 6, the interaction between a cam actuator, herein referred to as an interior drive bar 20, of the lock actuator 1 and the cam 10 can be derived. The interior drive bar 20 is provided with a drive lug 21 extending away from an outer surface of the interior drive bar 20. As can best be seen in Figure 6, the drive lug 21 is sized to fit within an appropriate interior slot 12 of the cam 10, such that rotation of the interior drive bar 20 will, by means of the drive lug 21, be transferred to the sides of the interior slot 12 thus causing rotation of the cam 10. As is shown in Figure 6, the cam 10 has an internal shoulder 13 extending within the central bore 11. The internal shoulder 13 is itself provided with a bore therethrough, such that the interior drive bar 20 can fit within the hole in the internal shoulder 13. The interior slot 12 is provided in the internal shoulder 13, wherein the drive lug 21 will fit within the interior slot 12 when the drive lug 20 is located within the hole of the internal shoulder 13.

As can be seen in Figures 3 and 4, the exterior side 2 (key operated cylinder side) of the lock actuator 1 is also provided with an external drive bar 22. The interior drive bar 20 is held within the cam 10 as shown in Figure 3 and the external drive bar 22 is held within the key operated cylinder. When the key is inserted into the key operated cylinder, the end of the key will push against the external drive bar 22, pushing this against the interior drive bar 20; the force applied will be enough to push the interior drive bar 20 out of engagement of the interior slot 12 in the hole of the internal shoulder 13 in the core 10, and allow the external drive bar 22 to fit within the hole of the internal shoulder 13 instead. The external drive bar 22 also comprises a lug which will fit within the interior slot 12 of the internal shoulder 13 of the cam 10, thus allowing rotation of the key operated cylinder to be passed through to the cam 10. As will be evident from Figures 3 and 4, the interior drive bar 20 is ordinarily held in the engagement position with the cam 10 by means of the biasing means 30. In the Figures, the biasing means 30 is a compression spring 30, which acts upon the interior drive bar 20 to bias this into the hole of the interior wall 13 in the cam 10.

The interior drive bar 20 is also held within a core 40 of the lock actuator 1. The core 40 provides an intermediary element of the thumbturn mechanism 4, and is part of a general engagement mechanism of the thumbturn mechanism 4. The core 40 is sized and shaped to fit within the central bore 11 of the cam 10, and provides a means of interaction between a thumbturn shaft 60 and the cam 10 via the interior drive bar 20. The interior drive bar 20 fits within one end of the core 40, and comprises one or more radially extending wings 23. The radially extending wings 23 on the drive bar 20, are sized and shaped to fix within two corresponding slots 41 of the core 40, which can best be seen in Figure 6. The slots 41 on the core 40 extend in the longitudinal direction of the core 40, and allow the interior drive bar 20 to translate longitudinally through a bore 42 provided along the length of the core 40. The bore 42 is sized and shaped to hold the main, preferably cylindrical, body 24 of the interior drive bar 20, wherein the slots 41 hold the wings 23 of the interior drive bar 20, stopping relative rotation of the interior drive bar 20 and the core 40. The longitudinal slots 41 allow for the interior drive bar 20 to move into and out of engagement with the bore in the internal shoulder 13 of the cam 10. As described above, in the normal state of the lock actuator 1, the interior drive bar 20 is held in engagement with the cam 10, however with insertion of the key into the key cylinder, the external drive bar 22 will push the interior drive bar 20 into the core 40 and out of engagement with the internal shoulder 13 and interior slot 12 of the cam 10. As is also evident from the Figures, in particular Figure 5, the bore 42 through the core 40 also holds the biasing means or compression spring 30, tending to force the interior drive bar 20 into engagement with the cam 10.

As can be seen in Figure 5, the core 40 comprises one or more radially extending holes 43. The radially extending holes 43 are sized to accept one or more biased, or spring-loaded pins 25 of the interior drive bar 20. The spring-loaded pins 25 can be seen in the cross- sectional view of Figure 5, and will normally be held within the body of the interior drive bar 20. The relative position of the holes 43 on the core 40 with respect to the position of the interior drive bar 20, ensures that when the lock actuator 1 is in its normal configuration (not damaged, in particular) the interior drive bar 20 does not extend to the point where the spring-loaded pins 25 can engage with the holes 43. The interior drive bar 20 will be held further within the bore 42 of the core 40 by the presence of the key operated cylinder and, in particular, the exterior drive bar 22. This means that the interior drive bar 20 is able to slide back and forth within the longitudinal slots 41 of the core 40. The exterior drive bar 22 will be located such that the interior drive bar 20 cannot be pushed far enough out of the bore 42 of the core 40 by the compression spring 30, consequently the spring loaded pins 25 will not be in a location that they can fit within the holes 43 of the core 40 to block longitudinal movement of the interior drive bar 20.

Should, however, the lock and lock actuator 1 be vandalized such that the key operated cylinder is removed at the sacrificial cut 5, the compression spring 30 will act to push the interior drive bar 20 forward as there will be no exterior drive bar 22 acting against the interior drive bar 20. In this scenario, the interior drive bar 20 will be forced into full alignment with the bore in the internal shoulder 13 of the cam 10, such that the spring- loaded pins 25 align with the holes 43 in the core 40. The alignment of the spring-loaded pins 25 and holes 43 ensures that the spring-loaded pins 25 will be pushed into full engagement with the holes 43, thus locking the internal drive bar 20 into the core 40. The extension of the spring-loaded pins 25 and locking of these into the holes 43 ensures that the interior drive bar 20 can no longer move translationally within the bore 42 of the core 40, thus meaning that the interior drive bar 20 and core 40 are locked into permanent connection and alignment. Evidently, therefore, the vandal on the exterior of the lock is not able to push the interior drive bar 20 into the lock actuator 1 at all, and cannot gain access to try and rotate the cam 10 after snapping of the lock actuator 1. Further elements of ensuring that the vandal cannot access the lock and rotate it can 10 are described in more detail below.

As can further be seen in Figures 5 and 6, the exterior surface of the core 40 is provided with a circumferential slot, herein called a first circumferential slot 44. The first circumferential slot 44 aligns with inwardly projecting cam pins 14. The cam 10 comprises one or more cam pins 14, wherein the one or more cam pins 14 extend within the bore 11 of the cam 10 and into the first circumferential slot 44 of the core 40. After the core 40 has been positioned within the bore 11 of the cam 10, one or more cam pins 14 are positioned through holes in the cam 11 and extend into the first circumferential slot 44. The cam pins 14 thus properly hold the core 40 within the bore 11 of the cam 10, ensuring that the cam 10 and core 40 form an integrated unit. The cam pins 14 act to stop longitudinal, translational movement of the core 40 within the bore 11 of the cam 10, but do not impede the rotation of the core 40 within the bore 11 of the cam 10.

As is clear from the above, rotation of the core 40 will lead to rotation of the interior drive bar 20. If the interior drive bar 20 is held in engagement with the interior slot 12 in internal shoulder 13 of the cam 10, rotation of the core 40 will, via the interior drive bar 20, also lead to rotation of the cam 10 and operation of the lock.

In the lock actuator 1 described above, and in particular without a further locking means to stop the rotation of the core 40 within the lock actuator 1, vandalism of the lock actuator 1 and removal of the key operated cylinder would allow the vandal to be able to rotate the interior drive bar 20 or even the cam 10, in order to lock and unlock the locking mechanism. By selectively blocking rotation of the core 40, the lock actuator 1 can then block operation of the lock; in particular, in the present lock actuator 1 blocking the rotation of the core 40 will block rotation of the cam 10 from the exterior side 2, whilst allowing the core 40 to be rotated from the inside by rotation of the thumbturn 7. Selective blocking of rotation of the core 40 is achieved by means of a split pin 50, which is seen most clearly in Figure 3. The split pin 50 is provided with a first, upper pin 51, a second or lower pin 52, and a biasing means shown in the form of the spring 53. The spring-loaded or biased split pin 50 is shown in each of the Figures as being located in the thumbturn mechanism 4 of the lock actuator 1, but this split pin 50 need only be positioned at an interior section of the lock actuator 1 away from the possible attack from the vandal. The core 40 is provided with a radially extending pin hole 45 which passes through the wall of the core 40 through to the bore 42. The core 40 is configured such that the pin hole 45 will align with the position of the split pin 50, such that both the upper pin 51 and lower pin 52 can be biased into the pin hole 45. It will be evident, in particular from Figure 3, that in certain situations the split pin 50 will be held within the pin hole 45 such that the lower pin 52 straddles the shear line between the core 40 and the housing of the lock actuator 1. As the lower pin 52 straddles this shear line, the core 40 may not be rotated within the lock actuator 1, thus locking the core 40 and the interior drive bar 20 from being able to rotate. Considering the situation shown in Figures 5 and 6, wherein the key operated cylinder has been removed from the lock actuator 1 and the interior drive bar 20 has been pushed forward to engage with the cam 10 and the spring loaded pins 25 are within the holes 43, rotation of the core 40 will lead to rotation of the cam 10 - by blocking this rotation, by means of the split pin 50, the cam 10 is also locked.

The split pin 50 is moved by a thumbturn shaft 60 as it is operated to actuate the cam 10. The thumbturn shaft 60 is held in a translationally free and rotationally free manner within the lock actuator 1, and is used to selectively position the split pin 50 to allow rotation of the core 40. The thumbturn shaft 60 is provided with a first end which is sized to fit within the bore 42 of the core 40, wherein the thumbturn shaft 60 is able to slide longitudinally within the bore 42 of the core 40 against the bias of the spring 30. At the distal end of the thumbturn shaft 60 held within the bore 42 of the core 40, the diameter of the thumbturn shaft 60 is smaller than the diameter of the bore 42 of the core 40. In this situation, the smaller diameter section 61 of the thumbturn shaft 60 will not interact with the upper pin 51 of the split pin 50 and will not, therefore, act against the biasing spring 53. In this situation, the core 40 is still held rotationally fixed within the lock actuator 1. As can be seen in Figures 3 and 4, the smaller diameter section 61 of the thumbturn shaft 60 provides the second surface against which the compression spring 30 will act on the interior drive bar 20. The compression spring 30 will tend to act to push the thumbturn shaft 60 and interior drive bar 20 away from each other, thus ensuring that the internal elements of the lock actuator 1 are held under some force and in proper engagement with each other.

At a more proximal position of the first end of the thumbturn shaft 60, the thumbturn shaft 60 has a larger diameter section 62. The larger diameter section 62 has the same, or approximately the same, diameter as the bore 42 of the core 40. As will be evident looking at Figure 3, if the thumbturn shaft 60 is pushed further into the bore 42 of the core 40, the smaller diameter section 61 will pass over the top of the upper pin 51 of the split pin 50, such that the larger diameter section 62 eventually aligns with the upper pin 51. At this point, the larger diameter section 62 will act to push the upper pin 51 against the spring 53, such that the upper pin 51 lies completely within the pin hole 45 through the wall of the core 40, thus allowing the core 40 to rotate within the lock actuator 1. It will also be clear that to ensure that the split pin 50 allows or blocks rotation of the core 40 as above, the length of the upper pin 51 is the same as the thickness of the wall of the core 40. That is, the upper pin 51 will, when pushed into the pin hole 45, fully fill the pin hole 45 and ensure that the split in the split pin 50 aligns with the shear line between the core 40 and lock actuator 1.

In order to improve the movement of the thumbturn shaft 60 such that the larger diameter section 62 can align with the pin hole 45 and the upper pin 51 of the split pin 50, the thumbturn shaft 60 has an angled shoulder 63 making a transition between the smaller diameter section 61 and the larger diameter section 62 of the thumbturn shaft 60. Preferably, the upper edge of the upper pin 51 has a chamfered shoulder, which tends to match the angled shoulder 63 of the thumbturn shaft 60, such that movement of the thumbturn shaft 60 further into the bore 42 of the core 40 will cause the two angled surfaces to slide past each other, generally pushing the upper pin 51 and lower pin 52 against the spring 53, such that the split in the split pin 50 aligns with the shear line between the core 40 and the lock actuator 1. By pushing the thumbturn shaft 60 further within the bore 42 of the core 40, the core 40 is unlocked and is able to rotate with respect to the lock actuator 1 in order to lock and unlock the lock by rotation of the cam 10. It is in this manner that, after vandalism and fixing of the relative rotation of the drive bar 20 into the core 40 and interlocking engagement with the cam 10, the core 40 can be allowed to rotate with rotation of the thumbturn shaft 60 on the interior of the lock and the lock may be opened safely by means of the thumbturn mechanism 4 of the lock actuator 1. This ensures that even after vandalizing the lock actuator 1, in particular after removal of the key operated cylinder, a person on the interior of the locked door or window can still easily and normally operate the lock actuator 1 and open the door or window. In this manner, the lock actuator 1 provides both vandalism protection and safety for users in a convenient single unit.

Looking at Figures 2, 3 and 4, the mechanism by which the thumbturn shaft 60 is held within the lock actuator 1 can be seen. At its second, proximal end 66 the thumbturn shaft 60 comprises a circumferential slot, herein called a second circumferential slot 64. The second circumferential slot 64 generally aligns with a fixed pin 54 within the lock actuator 1. The fixed pin 54 extends into the second circumferential slot 64 of the thumbturn shaft 60, and will allow rotation of the thumbturn shaft 60 but will stop the thumbturn shaft 60 from disengaging from the lock actuator 1. The top of the fixed pin 54 is held within the second circumferential slot 64, meaning that the thumbturn shaft 60 cannot disengage. The second circumferential slot 64 passes completely around the external surface at the second end 66 of the thumbturn shaft 60, thus allowing full 360° rotation of the thumbturn shaft 60 within the lock actuator 1.

As is clear from the above regarding the split pin 50, the thumbturn shaft 60 must be able to longitudinally transition from a first locking position, in which the larger diameter section 62 of the thumbturn shaft 60 does not align with the split pin 50, through to an unlocked orientation where the larger diameter section 62 overlaps with the split pin 50 thus allowing rotation of the core 40. In order to allow translational movement of the thumbturn shaft 60 within the lock actuator 1, the second circumferential slot 64 is provided with an indent 65. The indent 65 can best be seen in Figure 2, wherein in Figure 2 the fixed pin 54 is located within the indent 65. The compression spring 30 will tend to push the thumbturn shaft 60 away from the core 40, and the rest position of the thumbturn mechanism 4 is that in which the smaller diameter section 61 of the thumbturn shaft 60 aligns with the split pin 50. In this scenario, the fixed pin 54 is within the indent 65, thus meaning that the thumbturn shaft 60 is in a less inserted position within the bore 42 of the core 40. User operated pushing of the thumbturn 7 will push against the thumbturn shaft 60, to which the thumbturn 7 is attached, thus moving the fixed pin 54 into the second circumferential slot 64 and thus allowing the rotation of the thumbturn shaft 60 past the fixed pin 54. The longitudinal movement of the thumbturn shaft 60 further means that the angled shoulder 63 will then push the split pin 50 through the pinhole 45 in the core 40, thus making sure that the split in the split pin straddles the shear line between the core 40 and lock actuator 1. This further means that rotation of the first core 40 can proceed meaning that the thumbturn mechanism 4 of the lock actuator 1 is in the unlocked state. In order to ensure this action, and as is best seen in Figure 3: when the fixed pin 54 is held within the indent 65, the angled shoulder 63 rests against the top of the upper pin 51. This means that any motion of the thumbturn shaft 60 will immediately start to move the split pin 52 and unlock the rotation of the core 40 within the lock actuator 1. In order to more smoothly operate the translational and rotational motion of the thumbturn shaft 60, the indent 65 of the thumbturn shaft 60 can be provided with a chamfer 67 such that simple rotation of the thumbturn 7 will be possible and the rotational action will also then move the thumbturn shaft 60 into the bore 42 of the core 40, thus unlocking the rotation of the core 40 by movement of the split pin 50.

Figures 2 and 6 show how the translational and rotational movement of the thumbturn 7 and thumbturn shaft 60 will engage with the core 40, allowing rotation of the core 40 and operation of the cam 10. The second interior end of the core 40 is provided with one or more longitudinal slots 46 extending from the second end toward the first end. Aligned with these longitudinal slots 46 are one or more drive pins 68 of the thumbturn shaft 60, extending along the longitudinal direction of the thumbturn shaft 60. The drive pins 68 will fit within the longitudinal slots 46 on the core 40, such that rotation of the thumbturn shaft 60 will lead to rotation of the drive pins 68 and these in turn will push against the sides of the longitudinal slots 46 and rotate the core 40. As can be seen in Figure 2, the opening to the one or more longitudinal slots 46 is provided with a chamfer 47, or wider portion, leading into the longitudinal slot 46, and preferably the ends of the drive pins 68 may have a chamfer 69 which ensures smooth engagement into the longitudinal slots 46.

As is clear, when the thumbturn 7 is rotated by the user, the rotational action will lead to the fixed pin 54 acting on the chamfer 67 to move the thumbturn shaft 60 further into the bore 42 of the core 40. The movement of the thumbturn shaft 60 into the bore 42 of the core 40 means that the angled shoulder 63 will push against the spring 53 of the split pin 50, and the upper pin 51 will align fully through the wall in the core 40. This location of the split pin 50 will unlock the core 40 and allow rotation of the core 40 in the lock actuator 1, which will also coincide with the fixed pin 54 moving into the second circumferential slot 64 of the thumbturn shaft 60. The drive pins 68 will then engage with the longitudinal slot 46 on the core 40, such that continued rotation of the thumbturn 7 will lead to rotation of the core 40. The rotating core 40 will then, by means of the interior drive bar 20, rotate the cam 10 to open and close the lock. It will be fairly clear that this operation of the thumbturn mechanism 4 of the lock actuator 1 is completely unaffected by removal of the key operated cylinder, thus ensuring that a user of the interior side 3 of the lock actuator 1 can always open and close the lock.

Considering Figure 7, this shows a modification to the longitudinal slot 46 in the core 40 in the form of guider 70. Guider 70 can be seen in perspective in Figure 8. Guider 70 has a generally U-shaped form, comprising two guider arms 71 joined at the U-end 72. Ideally, the overall shape of the guider 70 is such that is fits snugly into the longitudinal slot 46, with the two guider arms 71 extending out of the longitudinal slot 46 into the region of the chamfer 47 of longitudinal slot 46. Longitudinal slot 46 can have an approximately straight-sided form, not shown in the Figures, extending along the longitudinal axis of the lock actuator 1 away from the opening to the end of the slot. Alternatively, as shown in Figure 7, the longitudinal slot 46 may have a narrower neck at the end of the slot and start of the chamfer 47 which then opens into a wider closed end region of the longitudinal slot 46. This form of the longitudinal slot 46 is advantageous, as the guider 70 can have a matching external form which then is held properly in position by means of the narrower neck on the longitudinal slot 46.

Figure 8 shows the guider 70 comprising a larger diameter U-end 72 when compared with the gap between the two adjacent guider arms 71. U-end 72 is shaped to fit within the end of the longitudinal slot 46, the two guider arms 71 advantageously have a gap there between which matches the narrower neck of the longitudinal slot 46. As can be seen in Figure 7, the two guider arms 71 are longer than the narrow neck of the longitudinal slot 46 and extend outward from the longitudinal slot 46 into the region of the chamfer 47. The guider arms 71 do not splay out in conformance with the chamfer 47, rather they extend toward the drive pin 68 to such an extent that they will be able to engage with the tip of the drive pin 68 and the chamfer 69 at the end thereof, when present. In particular, guidance lips 73 are provided at the end of each of the guider arms 71, the guidance lips 73 extending away from the U-end 72 and generally apart from each other. The guidance lips 73 thus form a guidance space 74 there-between, the guidance space 74 being used to accommodate the end of the drive pin 68, in particular the chamfer 69 thereof. Preferably, the rest state of the guider arms 71 means that the guidance space 74 is slightly smaller than the chamfer 69 at the end of the drive pin 68, such that the guider arms 71 are bent slightly outward from each other when the drive pin 68 is present.

The guider 70 is preferably formed from a single, bent piece of spring steel. This material can be formed to have a very smooth surface which also presents low friction to the drive pin 68 held within the guidance space 74. In particular, the drive pin 68 can be formed from steel, preferably hardened steel, such that the interaction between the drive pin 68 and the guider 70 is low friction and very smooth. It will further be appreciated that when the drive pin 68 is engaged with the guider 70 and the thumbturn 7 is rotated, the torque is transmitted via the drive pin 68 and the guider 70 to rotate the core 40. As will also be clear, when the thumbturn 7 is in the rest position, as shown in Figure 7, such that it has not been pushed forward to engage with rotating the cam 10, the guidance space 74 and guidance lips 73 will assist in holding the drive pin 68 in alignment with the longitudinal slot 46. When the user wishes to operate the thumbturn 7 to engage with the cam 10 via the core 40, the guider arms 71 will already begin to align the neck of the longitudinal slot 46 with the end of the drive pins 68 and thereby improve the engagement of the drive pins 68 with the guider 70 to operate the lock actuator 1.

Normal operation of the lock actuator 1 will now be described in connection with Figure 3, as this shows the lock actuator 1 in a non-vandalised condition, that is: the exterior side 2 is still in connection with the lock actuator 1. In the condition seen in Figure 3, the interior drive bar 20 is engaged with the interior slot 12 of the cam 10 by the biasing action from the spring 30. As the external drive bar 22 is also in position in the exterior side 2, the interior drive bar 20 will be held within the longitudinal slots 41 of the core 40 without the one or more spring loaded pins 25 aligning with the one or more holes 43 in the core 40. This means that the interior drive bar 20 is still able to slide within the bore 42 and the longitudinal slots 41 of the core 40, against the bias from the spring 30. If a key is inserted into the key cylinder on the exterior side 2, the key will push the external drive bar 22 against the interior drive bar 20 and will act against the bias from the spring 30 to slide the interior drive bar 20 out of engagement with the interior slot 12 of the cam 10; the external drive bar 22 will then engage with the interior slot 12 of the cam 10 and, assuming the key is the correct one, rotation of the key operated cylinder will lead to rotation of the external drive bar 22 and also the cam 10 to open and close the lock. In this case, the cam 10 will rotate around the stationary core 40 and interior drive bar 20, this is assisted by means of the cam pins 14 running through the first circumferential slot 44 of the core 40. It is also of note that the cam pins 14 interacting with the first circumferential slot 44, also stop the cam 10 from being pushed back into the lock actuator 1 by a vandal: the core 40 is stopped from being pushed out of the housing of the lock actuator 1 by the split pin 50 and the fixed pin 54. This feature further improves the security of the lock actuator 1.

Operating the lock actuator 1 with the thumbturn mechanism 4 can also be readily understood when considering Figure 3. When there is no key in the exterior side 2, the interior drive bar 20 is in engagement with the interior slot 12 of the cam 10, as described above. The drive bar 20 is, however, blocked from rotation in the scenario seen in Figure 3, as the wings 23 of the interior drive bar 20 are within the longitudinal slots 41 of the core 40 and thus cannot rotate with respect to the core 40. The core 40 is also rotationally fixed in place, as the lower pin 52 of the split pin 50 is biased by the spring 53 into the pin hole 45 of the core 40 and straddles the shear line between the core 40 and the housing of the lock actuator 1. In this state, the cam 10 and interior drive bar 20 are in engagement and in a rotationally locked position as a result of the core 40 being rotationally blocked by the split pin 50. That is, the lock actuator 1 is in a normally locked state.

In order to use the lock actuator 1 from the interior side 3, the user interacts with the thumbturn mechanism 4. By pushing the thumbturn 7 into the lock actuator 1, the thumbturn shaft 60 is pushed within the bore 42 of the core 40. As will be evident, the smaller diameter section 61 of the thumbturn shaft 60 will then move past the upper pin 51 of the split pin 50 until the angled shoulder 63 of the thumbturn shaft 60 starts to push against the top or chamfered edge of the upper pin 51. Continued pushing of the thumbturn 7 will push the thumbturn shaft 60 into full engagement with the bore 42 of the core 40, until the larger diameter section 62 aligns with the pin hole 45 and pushes the upper pin 51 fully into the pin hole 45. In this situation, the split in the split pin 50 aligns with the shear line between the core 40 and the housing of the lock actuator 1; the core 40 is now unlocked and can rotate within the housing of the lock actuator 1. Considering Figure 2, it will be clear that pushing the thumbturn 7 into the lock actuator 1 will also lead the drive pins 68 to engage with the longitudinal slots 46 of the core 40. As shown in Figure 7, if the guider 70 is present, the guider arms 71 will assist in guiding the drive pins 68 smoothly into the longitudinal slot 46 and will further allow the transfer of torque from the drive pins 68 to the core 40. After pushing the thumbturn 7 far enough into the lock actuator 1, the fixed pin 54 will move out of the indent 65 and into the second circumferential slot 64 of the thumbturn shaft 60. The thumbturn 7 and the thumbturn shaft 60 can then be rotated as the fixed pin 54 runs through the second circumferential slot 64, the drive pins 68 will be positioned within the longitudinal slot 46 of the core 40 and rotation of the thumbturn 7 will rotate the interior drive bar 20 and this will then turn the cam 10. In the situation where the indent 65 is provided with the chamfer 67, simple rotation of the thumbturn 7 will lead to the fixed pin 54 sliding along the sides of the chamfer 67 and will automatically slide the thumbturn 7 and thumbturn shaft 60 into the lock actuator 1, thus leading to both unlocking of the core 40 and then further rotation of cam 10. The situation where vandalism has acted upon the lock actuator 1 will now be described, and in particular reference is made to the images in Figures 5 and 6. When a vandal tries to gain access to the internal workings of the lock actuator 1 from the exterior side 2, the lock actuator 1 is intended to snap at the sacrificial cut 5. Each of Figures 5 and 6 shows the state of the lock actuator 1 when the exterior side 2 has been snapped off. If the exterior side 2 snaps off, the external drive bar 22 is no longer present to act against the interior drive bar 20, as described above and seen in Figure 3. Without the presence of the external drive bar 22, the interior drive bar 20 will be pushed by the spring 30 further into the cam 10 and further along the longitudinal slots 41 of the core 40. With continued sliding movement of the interior drive bar 20 from the biasing action of the spring 30, the spring loaded pins 25 will align with the holes 43 in the core 40 and will be biased into engagement therewith. This is the scenario seen in Figures 5 and 6, wherein the spring loaded pins 25 are located within the holes 43 of the core 40. In this case, the interior drive bar 20 is translationally locked into the core 40 and can no longer slide back further into the bore 42 of the core 40. The interior drive bar is thus fixedly held in permanent engagement with the interior slot 12 of the cam 10, and the vandal is not able to push the interior drive bar 20 out of engagement to try and gain access to the cam 10.

Crucially, with the interior drive bar 20 locked into permanent engagement with the cam 10 and translationally locked in the core 40, the cam 10 cannot be rotated from the exterior side 2 as the core 40 remains rotationally locked within the housing of the lock actuator 1, as described above. That is, the core 40 is rotationally locked in the housing of the lock actuator 1 by means of the split pin 50, and in particular by means of the lower pin 52 straddling the shear line between the core 40 and the housing of the lock actuator 1. With the core 40 rotationally locked, the interior drive bar 20 is rotationally locked and the cam 10 is rotationally locked. As the interior drive bar 20 cannot be disengaged from the interior slot 12 of the cam 10, the vandal is not able to cause rotation of the cam 10 from the exterior side 2 of the lock actuator 1. As discussed above, the cam pins 14 in the first circumferential slot 44 stop the core 40 from disengaging with the cam 10 and the fixed pin 54 in the second circumferential slot 64 further stops the thumbturn shaft 64 from disengaging from the lock actuator 1, in this way the locking mechanism is locked into the lock actuator 1 and the vandal is not able to push any items back into the lock actuator 1 to try and free up the cam 10.

It will be clear that the thumbturn mechanism 4 on the interior side 3 will continue to work as normal and as described above for the normal operation. The absence of the external drive bar 22 and the translational locking of the interior drive bar 22 into the core 40, will not affect the operation of the thumbturn mechanism 4 at all. In this way, the lock actuator 1 provides added vandalism protection whilst ensuring normal operation of the thumbturn mechanism 4 of the lock actuator 1.