AU2013202403B2 - A lock assembly and a method for converting a device between non lockable and key lockable - Google Patents

Abstract

A LOCK ASSEMBLY AND A METHOD FOR CONVERTING A DEVICE BETWEEN NON LOCKABLE AND KEY LOCKABLE A lock assembly (30) including a lock housing (32), a key cylinder assembly (38), a key cylinder barrel (40) and at least one releasable retention device (48). The key cylinder assembly (38) is mountable in or to the lock housing (32). The key cylinder barrel (40), which is within the key cylinder assembly (38), is pivotable relative to the key cylinder assembly (38) for locking and unlocking of the lock assembly (30) by a correctly coded key (44). The at least one releasable retention device (48) is movable between at least a first position, preventing removal of the key cylinder assembly (38) from the lock housing (30), and at least a second position, allowing removal of the key cylinder assembly (38) from the lock housing (30). The movement of the releasable retention device (48) to the at least second position, to allow removal of the key cylinder assembly (38) from the lock housing (30), being allowable responsive to the correctly coded key (44) being used to pivot the key cylinder barrel (40) to at least one extraction position and being prevented responsive to the correctly coded key (44) being used to pivot the key cylinder barrel (44) to at least one retaining position. 65 Iy bCD pp'p

Description

1 A LOCK ASSEMBLY AND A METHOD FOR CONVERTING A DEVICE BETWEEN NON LOCKABLE AND KEY LOCKABLE Field of the Invention [0001] The present invention relates to a lock assembly and a method for converting a device between non lockable and key lockable. [0002] The invention has been primarily developed for use with a window winder lock assembly and will be described hereinafter with reference to this application. However, the invention is not limited to this particular use and is also suitable for use and with other types of window and door locks. Background of the Invention [0003] Locks for new windows or doors are often fitted to the window or door at the factory where the window or door is manufactured and then sent to a building site for installation. If the building owner requires all locks in the house to be keyed alike (i.e. one key operating all or the majority of the locks in the house), then the following has to occur. Firstly, the builder orders all the locks for the house and requests that the locks are keyed alike. The locks are then sent to the window/door framing company, with identification of the house they belong to. The window/door framing company then installs the locks to the windows/doors and sends them to the correct house. Finally, the windows/doors arrive at the correct house and are installed. A disadvantage of this approach is that the sequence of steps described above is very difficult and complicated from a logistical view point and presents a real barrier to having all locks within a house keyed alike. [0004] An alternative approach is to have a builder order the window and door locks with different keys and then, after the house is finished, organise a locksmith to rekey all of the locks alike. This involves the locksmith completely removing the lock from each window and door as well as dismantling each of the locks to access the lock cylinders. A disadvantage of this approach is that it represents a very large additional cost to the builder.

2 [0005] Lock assemblies are known that are configured for ease of cylinder removal in order to simplify the rekeying process described above. However, such locks suffer from one or more of the following disadvantages. Firstly, they generally require access to rear of the lock for rekeying, thereby therefore requiring the lock to be removed from the door or window. Secondly, they require an additional key (distinct from the correct operating key) for cylinder removal and installation. This additional key can be lost or is controlled by the locksmith. Thirdly, these locks use a cylinder type and key that are not commonly used many countries and therefore are limited in the number of locks that they can be keyed alike to. [0006] Also known are interchangeable core cylinders, that simplify the interchangeability of similar cylinders to aid in rekeying alike. These cylinders are removed through the front face of the lock and do not require the lock to be removed from the window or door. However, a disadvantage of these cylinders is they require an additional control key to enable the interchangeable core cylinder to be removed and re-installed. This control key can be lost and/or is controlled by the locksmith. These cylinders are also not commonly used in many countries. A further disadvantage is these cylinders are more complicated to manufacture and are more expensive than more common lock cylinder types. [0007] Cylinders are also known, referred to as wafer or disc cylinders, that have barrels that can be removed from the lock to aid in rekeying alike. These barrels are retained in the lock with a sprung retaining clip on the rear of the barrel. However, a disadvantage of these cylinders is that there must be access to the rear of the barrel or an additional barrel removal key in order to remove them. Access to the rear of the barrel is generally through a hole that is inaccessible once the lock is mounted on a window or door, in order to maintain security. As result, this type of lock must be removed from the door/window in order to access the hole and the retaining clip. A further disadvantage of this type of cylinder is it generally to be considered to be of a low security level, and are generally not used on doors for this reason. Avoiding use on doors presents another disadvantage when attempting to key alike all locks within a building [0008] Removable core type cylinders are also known, which can be removed through the front face of the lock. The removal core cylinders are removed by loosening a retaining screw on the rear of the cylinder. However, as with the wafer/disc cylinders described above, access to the rear of the cylinder must be available in order to allow removal.

3 [0009] Another disadvantage of commonly available locks is the difficulty in transforming a non-key lockable lock into a key lockable lock. This conversion is genuinely too complex for the average householder and therefore requires the services and expense of a locksmith. Further, some locks do not allow such a conversion. Object of the Invention [0010] It is an object of the present invention to substantially overcome or at least ameliorate one or more of the above disadvantages. Summary of the Invention [0011] Accordingly, in a first aspect, the present invention provides a lock assembly including: a lock housing; a key cylinder assembly mountable in or to the lock housing; a key cylinder barrel, within the key cylinder assembly, and pivotable relative to the key cylinder assembly for locking and unlocking of the lock assembly by a correctly coded key; and at least one releasable retention device movable between at least a first position, preventing removal of the key cylinder assembly from the lock housing, and at least a second position, allowing removal of the key cylinder assembly from the lock housing, wherein the movement of the releasable retention device to the at least second position, to allow removal of the key cylinder assembly from the lock housing, being allowable responsive to the correctly coded key being used to pivot the key cylinder barrel to at least one extraction position and being prevented responsive to the correctly coded key being used to pivot the key cylinder barrel to at least one retaining position. [0012] The key cylinder assembly preferably includes a key cylinder mount, releasably mountable in the lock housing, in which a key cylinder is mountable, wherein the at least one releasable retention device, in the first position, prevents removal of the key cylinder mount and the key cylinder from the lock housing, and, in the second position, allows removal of the key cylinder mount and the key cylinder from the lock housing.

4 [0013] The key cylinder barrel is preferably pivotable to at least a locked position and an unlocked position and the at least one extraction position is intermediate the locked position and the unlocked position. [0014] The key cylinder barrel is preferably pivotable rotatable to at least a locked position and an unlocked position and the at least one retaining position includes the locked position and/or the unlocked position. [0015] The lock assembly preferably further includes a blocking part drivable by rotation of the key cylinder barrel responsive to said correctly coded key between at least a first position, preventing movement of the releasable retention device from the first position to the second position, and a second position, allowing movement of the releasable retention device from the first position to the second position, wherein, when the blocking part is in the second position, the releasable retention device can be moved from the first position to the second position to allow removal of the key cylinder assembly from the lock housing. [0016] Preferably when the blocking part is in the second position, the releasable retention device can be moved from the first position to the second position to allow removal of the key cylinder assembly from the lock housing by a tool or finger pressing on the releasable retention device. [0017] The lock assembly preferably further includes a push button, wherein, when the blocking part is in the second position, the releasable retention device can be moved from the first position to the second position to allow removal of the key cylinder assembly from the lock housing by the push button pressing on the releasable retention device. [0018] The blocking part preferably includes a recess into which at least part of the releasable retention device can move, into the second position, when the blocking part is in the second position, whereby, when the blocking part is in the second position, a finger or tool or push button can be used to move the releasable retention device from the first position to the second position, at least partially into the recess, to allow removal of the key cylinder assembly from the lock housing.

5 [0019] The lock housing preferably includes an access hole, the blocking part blocking the access hole in the first position and not blocking the access hole in the second position, whereby, when the blocking part is in the second position, a tool can be passed through the access hole and into operative engagement with the releasable retention device and used to move the releasable retention device from the first position to the second position to allow removal of the key cylinder assembly from the lock housing. [0020] The access hole is preferably substantially adjacent to the releasable retention device. [0021] The lock housing is preferably mountable to a surface and the movement of the releasable retention device to the second position responsive to the correctly coded key being used to pivot the key cylinder barrel to the at least one extraction position allows removal of the key cylinder assembly from the lock housing without requiring removal of the lock housing from the surface. [0022] The key cylinder is preferably of the pin cylinder type or the wafer cylinder type. [0023] The lock housing preferably includes a key cylinder assembly opening and the key cylinder assembly includes a key cylinder mount mountable in the key cylinder assembly opening. [0024] In a second aspect, the present invention provides a method of converting a device from key lockable to non lockable, the device including: a housing; a key cylinder assembly mountable in or to the housing; a key cylinder barrel, within the key cylinder assembly, and pivotable relative to the key cylinder assembly for locking and unlocking of the device by a correctly coded key; and at least one releasable retention device movable between at least a first position, preventing removal of the key cylinder assembly from the housing, and a second position, allowing removal of the key cylinder assembly from the housing, the movement of the releasable retention device to the second position allowing removal of the key cylinder assembly from the lock housing, being allowable responsive to the correctly coded key being used to pivot the key 6 cylinder barrel to at least one extraction position and being prevented responsive to the correctly coded key being used to pivot the key cylinder barrel to at least one retaining position, the method including the steps of: using the correctly coded key to pivot the key cylinder barrel to the at least one extraction position; moving the at least one releasable retention device to the second position; removing the key cylinder assembly from the housing; mounting a non lockable plug in or to the housing; and positioning the at least one releasable retention device in the first position to retain the mounting of the non lockable plug in or to the housing. [0025] The key cylinder assembly preferably further includes a key cylinder mount, releasably mountable in the lock housing, in which the key cylinder barrel is mountable and the method further includes the step of removing the key cylinder mount and the key cylinder barrel from the housing whilst the at least one releasable retention device is moved to the second position. [0026] In a third aspect, the present invention provides a method of converting a device from non lockable to key lockable, the device including: a housing; a non lockable plug mountable in or to the housing; and at least one releasable retention device movable between at least a first position, preventing removal of the non lockable plug from the housing, and a second position, allowing removal of the non lockable plug from the housing, the method including the steps of: moving the at least one releasable retention device to the second position; removing the non lockable plug from the housing; mounting a key cylinder assembly in or to the housing; and positioning the at least one releasable retention device in the first position to retain the mounting of the key cylinder assembly in or to the housing, whereafter the movement of the releasable retention device to the second position is allowable responsive to a correctly coded key being used to pivot a key cylinder barrel, relative to the key cylinder assembly, to at least one extraction position and is prevented responsive to 7 the correctly coded key being used to pivot the key cylinder barrel, relative to the key cylinder assembly, to at least one retaining position. [0027] The key cylinder assembly preferably further includes a key cylinder mount, releasably mountable in the lock housing, in which the key cylinder barrel is mountable and the method further includes the mounting the key cylinder mount and the key cylinder barrel in or to the housing whilst the at least one releasable retention device is moved to the second position. Detailed Description of the Drawings [0028] Preferred embodiments of the invention will now be described, by way of examples only, which reference to the accompanying drawings in which: [0029] Fig. 1 is a top view of a first embodiment of a window winder lock assembly; [0030] Fig.2 is a top perspective view of the lock assembly shown in Fig. 1; [0031] Fig. 3 is a partial cut away bottom perspective view of the lock assembly shown in Fig. 1, in a cylinder retention position; [0032] Fig. 4 shows the lock assembly in Fig. 3 in a cylinder extraction position; [0033] Fig. 5 shows the lock assembly of Fig. 4 during an initial extraction step; [0034] Fig. 6 shows the lock assembly of Fig. 5 after cylinder extraction; [0035] Fig. 7 is a top view of the lock assembly shown in Fig. 4; [0036] Fig. 8 is a top view of the lock assembly shown in Fig. 5; [0037] Fig. 9 is a top view of the lock assembly shown in Fig. 6; [0038] Fig. 10 is a top perspective view of the lock assembly shown in Fig. 1 during installation of a non-lockable cylinder; 8 [0039] Fig. 11 shows the lock assembly of Fig. 10 during conversion to a lockable cylinder; [0040] Fig. 12 is partial cut away top view of lock assembly shown in Fig. 1, in a cylinder retention position and locked; [0041] Fig. 13 shows the lock assembly of Fig. 12 with a drive chain fitted; [0042] Fig. 14 is a partial top cut away view of lock assembly shown in Fig. 1 in the cylinder retention position and the lock unlocked; [0043] Fig. 15 shows the lock assembly of Fig. 14 in a cylinder extraction position and unlocked; [0044] Fig. 16 is a partial cut away perspective view of a second embodiment of window winder lock assembly, in a cylinder retention position and locked; [0045] Fig. 17 shows the window winder of Fig. 16 in a cylinder retention position and locked; [0046] Fig. 18 shows the window winder of Fig. 16 in a cylinder retention position and unlocked; [0047] Fig. 19 shows the window winder of Fig. 16 in a cylinder extraction position; [0048] Fig. 20 shows the window winder of Fig. 16 with a cylinder plug fitted; [0049] Fig. 21 is a perspective view of a third embodiment of a plunger type lock assembly; [0050] Fig. 22 is a perspective view of a fourth embodiment of a sliding door lock assembly; and [0051] Fig. 23 is an exploded perspective view of an alternative form of key cylinder assembly.

9 Detailed Description of the Preferred Embodiments [0052] Figs. I to 15 show a first embodiment of a window winder lock assembly 30. The lock assembly 30 includes a housing 32, a winder handle 34 and a pair of openings 36, through which fasteners (not shown) are passed to fasten the lock assembly 30 to a window frame. [0053] The lock assembly 30 also include a key cylinder assembly 38 which includes a key cylinder mount 39, to which is mounted a key cylinder 41. A key cylinder barrel 40 is mounted within the key cylinder 41 (see Fig. 11). The upper rear surface of the housing 32 includes a (first) access hole 42. The key cylinder assembly 38 is releasably mounted in an opening 32a (see Fig. 6) in the housing 32, as will be described in more detail below. [0054] Fig. 3 shows the bottom of the key cylinder mount 39 and the key cylinder barrel 40, with a correct key 44 inserted within the key cylinder barrel 40. The key cylinder mount 39 is retained mounted to the housing 32 by a shoulder 46 on one side of the mount 39, which engages with the housing 32, and a releasable retention device, in the form of slide 48, which engages with a recess 49 on the opposite side of the mount 39. The slide 48 is mounted to the housing 32. An eccentric drive protuberance 50 is provided on the rear of the barrel 40. [0055] Fig. 3 shows the slide 48 in a first position preventing the removal of the key cylinder assembly 38 (i.e. the key cylinder mount 39 and the key cylinder 41) from the housing 32. Fig. 3 also shows a blocking part 52 which is driven to a first position by the rotation of the protuberance 50 by the key 44. The blocking part 52 includes a (second) access hole 54 therein. [0056] Fig. 4 shows a spring 56, which biases the slide 48 towards the first position shown in Figs. 3 and 4. Fig. 4 also shows a rocker 58 having a first end 58a and a second end 58b. [0057] Returning to Fig. 3, it can be seen that the protuberance 50 positions the blocking part 52 with the access holes 42 and 54 not aligned. As a result, a tool 60 cannot be passed through the access holes 42 and 54 into engagement with the rocker 58. Accordingly, when the key 44 is used to drive the protuberance 50 to the first position shown, the blocking part 52 prevents movement of the slide 48 from the position shown by preventing movement of the rocker 58. As a result, removal of the key cylinder assembly 38 from the housing 32 is prevented.

10 [0058] Fig. 4 shows the key 44 rotated to a second position which causes the protuberance 50 to drive the blocking part 52 to a second position. As best seen in Fig. 5, in this second position, the access holes 42 and 54 are aligned and the tool 60 can be passed through the holes 42, 54 and pressed against the second end 58b of the rocker 58. As shown in Fig. 6, pressing the tool 60 in the direction of arrow 61 pivots the rocker 58 and drives the first end 58a into a sloping cam surface 48a on the slide 48, thereby causing the slide 48 to move in the direction of arrow 62 to a second position where it is no longer in engagement with the recess 49 in the mount 39. As a result, the key cylinder assembly 38 can be removed from the housing 32. [0059] Figs. 7, 8 and 9 correspond to Figs. 4, 5 and 6 respectively and also demonstrate the movement of the slide 48 from the first position to the second position after which the key cylinder assembly 38 can be removed from the housing 32. [0060] The lock assembly 30 advantageously allows the key cylinder assembly 38, and thus the key cylinder 41, to be quickly and easily removed from the lock assembly. Importantly, this can be performed without requiring access to the rear of the lock assembly 30 and therefore without requiring disassembly of the lock assembly 30 from an associated window frame. A replacement key cylinder assembly 38 can then be substituted, which has been keyed alike to the majority of the other locks in the house, relatively quickly and easily, and without requiring the services of a locksmith. A further advantage of the lock assembly 30 is that the positioning of the blocking part between allowing access to the rocker and not allowing access to the rocker is controlled solely by the correct key, which is both convenient and maintains security. [0061] A further advantage of the lock assembly 30 should now be described with reference to Figs. 10 and 11. [0062] Fig. 10 shows a non key lockable version of window winder 30' produced from the (key lockable) lock assembly 30 shown in Figs. 1 to 9. The window winder 30' uses a non key lockable plug 70 in place of the key cylinder assembly 38 previously described. The plug 70 contains a rearward protuberance 72 which positions the blocking part 52 in the same position as shown in Figs. 4 to 9. The window winder 30' can be quickly and easily converted back to key lockable by using the tool 60 to extract the plug 70 from the housing 32, in a similar manner as was previously described in extracting the key cylinder assembly 38, and then replacing it with the key cylinder assembly 38.

11 [0063] Fig. 11 shows an alternative non key lockable version of window winder 30" produced from the (key lockable) lock assembly 30 shown in Figs. 1 to 9. The window winder 30" uses a key cylinder plug 80 in place of the key cylinder 41. The plug 80 contains a rearward protuberance 82 which positions the blocking part 52 in the same position as shown in Figs. 4 to 9. The key cylinder plug 80 is fixed to the mount 39 by brackets 38a and 38b, which are retained by screws 38c and 38d respectively. The window winder 30" can be quickly and easily converted back to key lockable by using the tool 60 to extract the plug 80 from the housing 32, in a similar manner as was previously described in extracting the key cylinder assembly 38. The brackets 38a and 38b are then disassembled to allow the plug 80 to be removed and replaced with the key cylinder 41. The key cylinder 41 is then fixed to the mount 39 by the brackets 38a and 38b. The key cylinder mount 39 is then installed in the opening 32a in the housing 32. [0064] An alternative form of key cylinder assembly 38' is shown in Fig. 23, in which the key cylinder barrel is mounted directly to the key cylinder mount 39 and the previously described brackets and key cylinder are integrally formed with the key cylinder mount 39'. [0065] Fig. 12 shows the lock assembly 30 previously described and shows the key 44 in a locking position. In this position, the access holes 42 and 54 are not aligned so the tool 60 can not be used to remove the key cylinder assembly 38. Further, a locking bar 90 is biased by a spring (not shown) to a position engaging a locking gear 92, thereby preventing it from rotating. As shown in Fig. 13, the gear 92 is connected to a chain gear 94 which is in turn connected to a worm drive 95. The worm drive 95 is rotated by rotation of the handle 34. The rotation of the worm drive 95 rotates the chain gear 94, which in turn drives a chain 96 that terminates in a window bracket 98. Accordingly, as the locking gear 92 is preventing from rotating so to is the chain gear 94. Accordingly, opening of the window is prevented by the locking bar 90 being positioned to engage the locking gear 92. [0066] Fig. 14 shows a lock assembly 30 with the key 44 rotated to an unlock position in which the locking bar 90 is driven free of engagement from the locking gear 92, against the bias of its associated spring (not shown), by the protuberance 50. Accordingly, in this position, rotation of the handle 34 will cause rotation of the worm drive 95 and the chain gear 94 and cause the bracket 98 to be driven by the chain 96 away from the lock assembly 30 to open the window. Importantly, in this position, the access holes 42 and 54 are also not aligned and so the tool 60 can not be used to remove the key cylinder 38 from the housing.

12 [0067] Accordingly, the lock assembly 30 is advantageously secure from key cylinder assembly removal in both the locked and unlocked positions. [0068] Fig. 15 shows the key 44 rotated to a position where the protuberance 50 drives the blocking part 52 to a position in which the access holes 42 and 54 are aligned, thereby allowing removal of the key cylinder assembly 38 with the tool 60 as previously described. [0069] Figs. 16 to 20 show a second embodiment of a window winder lock assembly 100. The lock assembly 100 is very similar to the lock assembly 30 previously described and like features are indicated with like reference numerals. However, in the lock assembly 100, the blocking part 52 does not have an access hole but instead a recess 102 which can be positioned to prevent or allow pivotal movement of the rocker 58 (similar to that previously described) responsive to the pushing of the tool 60. [0070] More particularly, Figs. 16 shows the lock assembly 100 with the key cylinder barrel 40 in a locked position in which the protuberance 50 drives the blocking part 52 to a position where the second end 58b of the rocker 58 can not be pivoted to enter into the recess 102. Accordingly, pressing on the second end 58b of the rocker 58 with the tool 60 can not pivot the rocker 58 and thus the slider 48 can not be retracted and the key cylinder assembly 38 can not be extracted from the housing 32. [0071] Fig. 18 shows the key cylinder barrel 40 rotated by the key 44 to an unlocked position with the protuberance 50 positioning the blocking part 52 so that the second end 58b of the rocker 58 is also not in alignment with the recess 102. Extraction of the key cylinder assembly 38 from the housing 32 is thus prevented. [0072] Fig. 19 shows the barrel 40 and protuberance 50 rotated to a position aligning the second end 58b of the rocker 58 with the recess 102. As is shown, the tool 60 can then be used to pivot the second end 58b of the rocker 58 into the recess 102 which pivots the first end 58a into driving engagement with the slider 48. This movement drives the slider 48 out of engagement with the recess 49 in the cylinder mount 39, and allows the cylinder assembly 38 to be extracted from the housing 32 in a similar manner to that previously described.

13 [0073] Fig. 20 shows the lock assembly 100 after conversion to non lockable with a cylinder plug 104, similar to the plug 70. As with the first embodiment, the protuberance 106 on the rear of the cylinder plug 104 positions the blocking part 52 in the same position shown in Fig. 19 thereby allowing extraction of the plug 104 for quickly and easily converting the lock assembly 100 to key lockable. [0074] Fig. 21 shows a fourth embodiment of plunger type door lock 110, with a releasable key cylinder assembly 38 similar to those previously described. [0075] Fig. 22 shows a fourth embodiment of a sliding door lock 120, with a releasable key cylinder assembly 38 similar to those previously described. [0076] Although, the invention has been described with reference to preferred embodiments, it will be appreciated by persons skilled in the art of the invention may be embodied in many other forms. For example, in an alternative embodiment of the lock assembly (not shown), the lock assembly includes an opening large enough for a finger to be able to push against the rocker. In yet another embodiment (not shown), the lock assembly includes a push button to push against the rocker. In both of these embodiments, the finger or push button can only pivot the rocker when the blocking part is positioned to allow same.

Claims (17)

1. A lock assembly including: a lock housing; a key cylinder assembly mountable in or to the lock housing; a key cylinder barrel, within the key cylinder assembly, and pivotable relative to the key cylinder assembly for locking and unlocking of the lock assembly by a correctly coded key; and at least one releasable retention device movable between at least a first position, preventing removal of the key cylinder assembly from the lock housing, and at least a second position, allowing removal of the key cylinder assembly from the lock housing, wherein the movement of the releasable retention device to the at least second position, to allow removal of the key cylinder assembly from the lock housing, being allowable responsive to the correctly coded key being used to pivot the key cylinder barrel to at least one extraction position and being prevented responsive to the correctly coded key being used to pivot the key cylinder barrel to at least one retaining position.

2. The lock assembly as claimed in claim 1, wherein the key cylinder assembly includes a key cylinder mount, releasably mountable in the lock housing, in which a key cylinder is mountable, wherein the at least one releasable retention device, in the first position, prevents removal of the key cylinder mount and the key cylinder from the lock housing, and, in the second position, allows removal of the key cylinder mount and the key cylinder from the lock housing.

3. The lock assembly as claimed in claim 1 or 2, wherein the key cylinder barrel is pivotable to at least a locked position and an unlocked position and the at least one extraction position is intermediate the locked position and the unlocked position.

4. The lock assembly as claimed in claim 1 or 2, wherein the key cylinder barrel is pivotable rotatable to at least a locked position and an unlocked position and the at least one retaining position includes the locked position and/or the unlocked position.

5. The lock assembly as claimed in any one of the preceding claims, wherein the lock assembly further includes a blocking part drivable by rotation of the key cylinder barrel responsive to said correctly coded key between at least a first position, preventing movement of the releasable retention device from the first position to the second position, and a second 15 position, allowing movement of the releasable retention device from the first position to the second position, wherein, when the blocking part is in the second position, the releasable retention device can be moved from the first position to the second position to allow removal of the key cylinder assembly from the lock housing.

6. The lock assembly as claimed in claim 5, wherein, when the blocking part is in the second position, the releasable retention device can be moved from the first position to the second position to allow removal of the key cylinder assembly from the lock housing by a tool or finger pressing on the releasable retention device.

7. The lock assembly as claimed in claim 5 or 6, wherein the lock assembly further includes a push button, wherein, when the blocking part is in the second position, the releasable retention device can be moved from the first position to the second position to allow removal of the key cylinder assembly from the lock housing by the push button pressing on the releasable retention device.

8. The lock assembly as claimed in claim 5 or 6, wherein the blocking part includes a recess into which at least part of the releasable retention device can move, into the second position, when the blocking part is in the second position, whereby, when the blocking part is in the second position, a finger or tool or push button can be used to move the releasable retention device from the first position to the second position, at least partially into the recess, to allow removal of the key cylinder assembly from the lock housing.

9. The lock assembly as claimed in claim 5 or 6, wherein the lock housing includes an access hole, the blocking part blocking the access hole in the first position and not blocking the access hole in the second position, whereby, when the blocking part is in the second position, a tool can be passed through the access hole and into operative engagement with the releasable retention device and used to move the releasable retention device from the first position to the second position to allow removal of the key cylinder assembly from the lock housing. 16

10. The lock assembly as claimed in claim 9, wherein the access hole is substantially adjacent to the releasable retention device.

11. The lock assembly as claimed in any one of the preceding claims, wherein the lock housing is mountable to a surface and the movement of the releasable retention device to the second position responsive to the correctly coded key being used to pivot the key cylinder barrel to the at least one extraction position allows removal of the key cylinder assembly from the lock housing without requiring removal of the lock housing from the surface.

12. The lock assembly as claimed in any one of the preceding claims, wherein the key cylinder is of the pin cylinder type or the wafer cylinder type.

13. The lock assembly as claimed in any one of the preceding claims, wherein the lock housing includes a key cylinder assembly opening and the key cylinder assembly includes a key cylinder mount mountable in the key cylinder assembly opening.

14. A method of converting a device from key lockable to non lockable, the device including: a housing; a key cylinder assembly mountable in or to the housing; a key cylinder barrel, within the key cylinder assembly, and pivotable relative to the key cylinder assembly for locking and unlocking of the device by a correctly coded key; and at least one releasable retention device movable between at least a first position, preventing removal of the key cylinder assembly from the housing, and a second position, allowing removal of the key cylinder assembly from the housing, the movement of the releasable retention device to the second position allowing removal of the key cylinder assembly from the lock housing, being allowable responsive to the correctly coded key being used to pivot the key cylinder barrel to at least one extraction position and being prevented responsive to the correctly coded key being used to pivot the key cylinder barrel to at least one retaining position, the method including the steps of: using the correctly coded key to pivot the key cylinder barrel to the at least one extraction position; moving the at least one releasable retention device to the second position; removing the key cylinder assembly from the housing; 17 mounting a non lockable plug in or to the housing; and positioning the at least one releasable retention device in the first position to retain the mounting of the non lockable plug in or to the housing.

15. The method as claimed in claim 14, wherein the key cylinder assembly includes a key cylinder mount, releasably mountable in the lock housing, in which the key cylinder barrel is mountable and the method further includes the step of removing the key cylinder mount and the key cylinder barrel from the housing whilst the at least one releasable retention device is moved to the second position.

16. A method of converting a device from non lockable to key lockable, the device including: a housing; a non lockable plug mountable in or to the housing; and at least one releasable retention device movable between at least a first position, preventing removal of the non lockable plug from the housing, and a second position, allowing removal of the non lockable plug from the housing, the method including the steps of: moving the at least one releasable retention device to the second position; removing the non lockable plug from the housing; mounting a key cylinder assembly in or to the housing; and positioning the at least one releasable retention device in the first position to retain the mounting of the key cylinder assembly in or to the housing, whereafter the movement of the releasable retention device to the second position is allowable responsive to a correctly coded key being used to pivot a key cylinder barrel, relative to the key cylinder assembly, to at least one extraction position and is prevented responsive to the correctly coded key being used to pivot the key cylinder barrel, relative to the key cylinder assembly, to at least one retaining position. 18

17. The method as claimed in claim 16, wherein the key cylinder assembly further includes a key cylinder mount, releasably mountable in the lock housing, in which the key cylinder barrel is mountable and the method further includes the mounting the key cylinder mount and the key cylinder barrel in or to the housing whilst the at least one releasable retention device is moved to the second position. Gainsborough Hardware Industries Limited Patent Attorneys for the Applicant SPRUSON & FERGUSON