NZ756436B2 - Rim latch with safety release selectability - Google Patents

Abstract

This invention relates to a lock assembly (1) including a bolt (5) that is movable relative to a housing (3) between an extended and retracted position on operation of an inner actuator (6) or an outer actuator (7). A lock mechanism is included within the housing (3) that when in an active condition renders the inner actuator (6) inoperable. The lock assembly (1) also includes a lock release mechanism that when in a selected condition interacts with the operation of the outer actuator (7) with the lock mechanism so that operation of the outer actuator (7) adjusts the condition of the lock mechanism from the active condition to an inactive condition. A problem with the prior art is that those locks are typically one function or another, but the user cannot select different functions as desired. This is addressed in the present invention by providing a selectable function to improve on current locks. renders the inner actuator (6) inoperable. The lock assembly (1) also includes a lock release mechanism that when in a selected condition interacts with the operation of the outer actuator (7) with the lock mechanism so that operation of the outer actuator (7) adjusts the condition of the lock mechanism from the active condition to an inactive condition. A problem with the prior art is that those locks are typically one function or another, but the user cannot select different functions as desired. This is addressed in the present invention by providing a selectable function to improve on current locks.

Description

RIM LATCH WITH SAFETY E SELECTABILITY Technical Field This invention relates to a lock assembly for mounting to a movable barrier such as a door or gate. The lock ly includes a bolt movable between an extended position and a retracted position, and at least an inner actuator, such as a turn knob or the like, for moving the bolt towards a retracted position. The invention is particularly suitable for use with a surface mounted lock assembly, often referred to as a rim lock assembly, and it will be convenient to hereinafter describe the invention with reference to this particular application. It should be appreciated however that the invention may have other applications.

Background of Invention A rim lock assembly will generally include a housing that is attachable to a face of the door, and a bolt movable from an extended on to a retracted position.

The bolt is movable on an inner side of the door generally by operation of an inner turn knob or lever (hereinafter turn knob). The operation of the turn knob can be controlled by an inner (hereinafter first) key operated cylinder lock interacting with a lock mechanism within the housing. On an outer side of the door the bolt can be moved to a retracted position generally only by operating an outer (hereinafter second) key operated er lock or the like.

It can be desirable for the second key operated cylinder lock to also ct with the lock mechanism. More specifically the lock assembly may be installed in an environment where it is desirable that operating the second key operated lock to t the bolt, also s the condition of the lock mechanism to unlock or permit operation of the inner turn knob. One such environment is the front door to a house y once the occupier has operated the second key operated cylinder lock and gained access, it might be inconvenient for them to have to also unlock the lock ism to operate the inner turn knob. This onality can also reduce the likelihood of the occupier being inadvertently locked in the premises.

However there are other environments where this functionality is not desirable. One such environment is where the lock assembly is installed on a gate or other movable barrier where an unauthorised user can gain access to either side of the le barrier. In this environment it may be preferable that the lock mechanism remain locked even after operation of the second key operated lock. It may also be preferable for the lock ism to remain locked even after operation of the inner turn knob.

The applicant has appreciated that providing a lock ly that allows selection of such functions by the installer, particularly on site, would be advantageous.

A reference herein to a patent document or other matter which is given as prior art is not to be taken as an admission that that document or matter was, in Australia, known or that the information it ns was part of the common general knowledge as at the priority date of any of the claims.

Summary of Invention According to one aspect of this ion there is provided a lock assembly for use with a movable barrier, the lock assembly ing a g for positioning on an inner side of the movable barrier which houses a bolt, the bolt being movable relative to the housing between an extended position and a retracted position, a first or that is operable by rotation about an actuation axis at an inner side of the housing to cause movement the bolt from the extended position towards the retracted position, a lock mechanism within the housing that is adjustable between an active condition and an inactive condition so that when in an active condition renders the first actuator inoperable and when in an inactive condition renders the first actuator operable, a second actuator operable from an outer side of the housing to cause movement of the bolt from the extended on towards the retracted position, a lock release ism that is selectable so that when in a selected condition interacts the ion of the second actuator with the lock mechanism so that operation of the second actuator adjusts the condition of the lock mechanism from the active condition to an inactive condition, and when the lock release mechanism is in an unselected SPEC-NZ21898-19.docx condition does not ct the operation of the second actuator with the lock mechanism.

The second actuator may include a ble member that is rotatable about the actuator axis to cause movement of the bolt from the extended position towards the retracted position, and in which case it is preferred that the lock release mechanism includes a release member that is associated with the rotatable member when the lock release mechanism is in the selected condition. The rotatable member may take any suitable form and one red form is as a cam that is rotatable about the actuation axis to cause liner movement of the bolt. However the invention is not limited to linear movement of the bolt only and the bolt may for example move by pivoting about an axis. The bolt may take any suitable for and in a preferred form it includes a bolt head and a bolt body with the bolt body formed with a shoulder, the cam being formed with a projection that engages the shoulder when moving the bolt.

The manner in which the bolt and cam interact may clearly vary from this arrangement. The release member may by oned in any suitable location and one location is having the release member is positioned on the cam when the lock release mechanism is in the selected ion, and d in ly inwardly of the projection on the cam.

The configuration of the housing may take any suitable form however it is preferred that a backing plate be included that is attachable with the housing, the backing plate being configured to accommodate the rotatable member so as to allow rotation relative thereto. It is further preferred that the rotatable member be detachable from the backing plate so as to facilitate locating the release member thereon, however this is not essential. It is further preferred to a first limiter that is associated with the backing plate and interacts with the rotatable member to limit the extent of rotation of the rotatable member in one direction of rotation. This facilitates the ion of the second actuator in the t manner whereby rotation of the ble member in one ion only will result in retraction of the bolt. It is preferred that the first limiter is in the form of a screw and the backing plate is configured with a threaded aperture so that the first limiter can be detachably fastened to the backing plate to selectively limit the extent of rotation of the rotatable member. This arrangement facilitates installation of the first limiter, however clearly other arrangements are possible.

A lock mechanism preferably includes a drive member that is movable within the housing when the lock mechanism adjusts between the inactive condition and the active condition, and at least one detent that is e within the housing on movement of the drive member when the lock mechanism adjusts between the inactive condition and the active condition, wherein the drive member and the at least one detent are configured to interact with each other so that movement of the drive member causes relative movement of the at least one detent. It is further preferred that the drive member includes an abutment that interacts with the lock release mechanism when the lock release mechanism is in the selected condition. It is further preferred that the interaction occur when the second actuator is operated so as to adjust the condition of the lock mechanism from an active condition to an ve condition.

The lock assembly preferably includes a first key operated cylinder lock that is operable from an inner side of the housing to adjust the condition of the lock mechanism. It is further preferred that a cylinder cam be included that is rotatable on operation of the first key operated cylinder lock and engages the drive member to move the drive member within the housing. It is still further preferred to e a second r that is associated with the drive member and interacts with the cylinder cam to limit the extent of rotation of the cylinder cam. This ement prevents the key operating the first key operated cylinder lock to be removed without first returning the lock mechanism to the active condition. The second limiter interacts with the cylinder cam and the drive member so as to permit a key ed into the first er lock to be release only when the lock ism is in the active condition.

The second limiter may take any suitable form and one form is in the form of a screw and the drive member is configured with a threaded aperture so that the second limiter can be detachably fastened to the drive member to selectively limit the extent of rotation of the cylinder cam.

The at least one detent preferably includes a first detent and a second detent that are each movable radially ve to the actuation axis. The first detent is preferably driven radially outwardly on movement of the drive member as the lock mechanism adjusts from the inactive condition to the active condition. The second detent is driven radially dly on movement of the drive member as the lock ism adjusts from the inactive condition to the active condition, and driven radially inwardly on movement of the drive member as the lock ism adjusts from the active condition to the inactive condition. This arrangement is particularly suited to the situation where the lock assembly is installed where the first detent and second detent are on opposed sides of the actuator axis with the first detent on top of the actuator axis and the second detent is on the bottom of the actuator axis.

It is red that the drive member moves linearly within the housing, however it may move in other ways such as rotating.

It is preferred that the second actuator includes a second key operated cylinder lock. It is further red that the first key operated cylinder lock and or the second key ed cylinder lock are located relative to the actuation axis so that either or both are operable by rotating a key about the actuation axis. However this is not essential as either may alternatively be depressed in the direction of the ion axis. It is further preferred that the lock ly include a biasing means for biasing the bolt towards the extended position. The preferred form of lock assembly is a rim lock assembly where the bolt is a latch bolt, however the ion may apply to other forms of lock assembly.

A preferred embodiment of a lock assembly will be herein after described in greater detail by reference to the accompanying drawings. The detailed description and drawings are merely illustrative of how the invention might be put into effect so that the specific form and arrangement of the s features, as described and illustrated is not to be understood as ng on the invention.

Brief Description of Drawings Figure 1 is a diagrammatic isometric view of a preferred embodiment of the lock assembly when installed according to this invention.

Figure 2 is an exploded isometric view of a preferred embodiment of the lock assembly ing to the invention configured for the lock release mechanism to adopt the selected condition.

Figure 3 is a rear elevation view of the lock assembly with at least the backing plate removed to reveal the bolt in an extended position.

Figure 4 is a rear ion view of the lock assembly from Figure 3 with the bolt moved to retract a position on operation of the outer cam.

Figure 5 is a rear elevation view of the lock assembly with the backing plate removed to reveal the bolt in an extended position.

Figure 6 is a rear elevation view of the lock assembly from Figure 5 with the bolt moved to a retracted position on operation of the inner cam.

Figure 7 is a rear ion view of the lock assembly with the backing plate and bolt removed to reveal the lock mechanism in an active condition.

Figure 8 is a rear elevation view of the lock assembly from Figure 7 with the lock ism having been adjusted by the outer cam to adopt an inactive condition.

Figure 9 is a rear elevation view of the lock assembly with a backing plate and bolt removed to reveal the locking mechanism in an active condition, and a middle portion of the drive member shown as transparent to reveal the cylinder cam.

Figure 10 is a rear elevation view of the lock assembly from Figure 9 with the lock mechanism having been ed to an inactive condition on operation of a cylinder cam.

Figure 11 is the exploded isometric view from Figure 2 in reverse orientation.

Figure 12 is an exploded isometric view of a preferred embodiment of the lock assembly according to the invention configured for the lock release mechanism to adopt the unselected condition.

Figure 13 is the ed ric view from Figure 12 in reverse orientation.

Figure 14 illustrates the rear elevation view from figure 9 with a second limiter installed, with a lower portion shown as transparent to reveal the cylinder lock.

Figure 15 illustrates a cross section through XV-XV of figure 14.

Figure 16 is a rear elevation view of the lock assembly with backing plate attached to the housing and the first limiter installed.

Detailed Description Figure 1 illustrates a lock assembly 1 according to a preferred embodiment of the invention when installed on a door 2. The lock assembly includes a housing 3 which is attached to an inner side of the door and positioned nt a free edge 4 of the door 2. The lock assembly 1 includes a bolt 5 which projects to one side of the housing 3 when the bolt 5 is in an extended position as shown. The housing 3 is positioned relative to the edge 4 of the door 2 so that when the bolt 5 is in the extended position it is e of interacting with a strike (not shown) which in use is fixed on a doorjam (not shown) for retaining the door 2 in a closed on.

The lock assembly 1 includes an inner actuator 6 and an outer actuator 7 each of which is operable in a manner that will be described later in the specification, for moving the bolt 5 from the extended on as shown towards a retracted position. The inner actuator 6 illustrated includes a turn knob 8 which is rotatable about an actuation axis X-X so as to retract the bolt 5. The turn knob 8 illustrated can be tuted by a lever handle (not shown) if preferred. In contrast the outer actuator 7 illustrated is in the form of a key operated cylinder lock 9 which includes a barrel 10 being rotatable relative to a casing 11 about the actuation X-X, on insertion of appropriately coded key 12. The lock assembly illustrated in Figure 1 may be described as a rim lock assembly.

Figure 1 also illustrates the housing 3 having an aperture 13 positioned proximate the bolt 5. Whilst the location of the aperture 13 may vary from that as illustrated, to be located for e on the turn knob 8, the function of the re is to provide a viewing window through which an indicator member 14 (see Figure 2) can be made visible.

Referring now to Figure 2, which illustrates a specific form of the outer actuator 7 ing the cylinder lock casing 11 with a r bible 15 orientated ntially vertically. A tail bar 16 is positioned to engage with a barrel 10 of the cylinder lock 9. The length of a tail bar 16 may vary from that illustrated depending upon the thickness of the door 2 (See Figure 1) to which the lock assembly 1 is installed. When installed the tail bar 16 extends through a central re 17 formed in a g plate 18 to engage with an outer cam 19 which is rotatable about the actuator axis X-X (see Figure 1) on rotation of the tail bar 16.

It should be noted from Figure 2 that the outer cam 19 includes an axially ing projection 20 spaced radially from the centre of the outer cam 19. This projection 20 is positioned to interact with the bolt 5, or more specifically the bolt frame 21 when moving the bolt 5 between the extended and retracted positions. The interaction of the projection 20 with the frame 21 is more clearly illustrated in greater detail with reference to Figures 3 and 4 which illustrate a rear view of the lock assembly 1 partially assembled. The backing plate 18 and the majority of the outer cam 19 d. However, the projection 20 is visible. Figure 3 illustrates the bolt 5 in the extended position relative to the housing 3, being urged towards this position by a bolt torsion spring 21 having a free end engaging behind a head 22 of the bolt 5.

The bolt head 22 is connected to the bolt frame 21 and has an internally formed shoulder 23 oned adjacent the projection 20. When comparing Figure 4 with Figure 3 it is to be understood that the outer cam 19 has been rotated in an anti- clockwise direction to move the projection 20 through an arc which s in movement of the bolt 5 to the retracted position against the urging of the bolt torsion spring 21. The bolt 5 is considered to be in a retracted position when the bolt head 22 is within the housing 3, as can be seen in figure 4.

The assembly and operation of the inner actuator 6 will now be explained firstly with reference to Figure 2. The inner actuator 6 es the turn knob 8 which is illustrated in the form of a turn knob assembly including a hand grip element 25, an outer bearing plate 26, and an inner bearing plate 27. The outer bearing plate 26 and the inner bearing plate 27 are positioned on opposed sides of the lock g 3, and are d in this position by four screws 28 which locate in riately spaced apertures 29, 30 formed in the inner g plate 27 and outer bearing plate 26 respectively. The finger grip element 25 is formed with screw flutes 78 (see Figure 11) internally thereof for engagement with the four screws 28 so as to retain the finger grip element 25 adjacent the outer bearing plate 26. The outer bearing plate 26 also includes a radially extending channel 31 to receive the finger grip element 25 therein, so as to facilitate transferring any rotational force applied by the user on the finger grip element 25 through the outer bearing plate 26 to rotate the inner bearing plate Figure 2 also the inner actuator 6 also including an inner cam plate 32 which is spaced from the inner bearing plate 27 in Figure 2 by a drive member 33.

The function of the drive member 33 will be explained later in the specification. The inner cam plate 32 is attached to the inner bearing plate 27 by four screws 34 (only three of which are visible), so that rotation of the turn knob assembly 25, 26, 27 results in rotation of the inner cam plate 32. It can be appreciated from Figure 2 that the inner cam plate 32 is formed with a radially spaced projection 35 which is positioned to interact with the shoulder 23 on the bolt frame 21. The purpose of this engagement is described in greater detail with reference to Figures 5 and 6.

Figure 5 illustrates the rear view of the lock assembly 1, similar to Figure 3 with the outer cam plate 19 removed. The bolt 5 is shown in the extended position, urged towards that on by the bolt torsion spring 24. The turn knob 8, (see Figure 1), is in the horizontal position, whereby the projection 35 is spaced from the shoulder 23. When comparing Figures 5 and 6 it can be appreciated that rotation of the inner cam plate 32 causes the projection 35 to engage the shoulder 23 causing the bolt 5 to retract from the ed position illustrated in Figure 5 to the retracted on illustrated in Figure 6.

The lock assembly 1 according to the invention includes a lock mechanism, that when in an active condition the inner actuator is rendered able for retracting the latch bolt 5 from the extended position. The preferred elements of and method for ing this as illustrated in Figure 2 include the drive member 33 that is positioned between the inner cam plate 32 and inner bearing plate 27 in conjunction with an upper detent 36 and a lower detent 37. The drive member 33 es an upper ramp surface 38 and a lower ramp surface 39 for driving an upper detent 36 and lower detent 37 in a radial direction respectively on movement of the drive member 33 in a direction substantially perpendicular to the actuator axis X-X. The drive member 33 is moved as a result of engagement and rotation by either the outer cam plate 19 or the inner cylinder cam 40. This engagement and movement is more y illustrated in Figures 7 to 11.

Figure 7 illustrates a rear view of the lock assembly 1 with the backing plate 18, bolt 5, inner cam 32 and part of the outer cam 19 (see all in Figure 2) removed. The lock mechanism is shown in Figure 7 in an active condition. The internal configuration of the housing 3 is formed with an r bearing wall 41 which intermittently surrounds the inner bearing plate 27 defining a space within which the inner bearing plate 27 can rotate when the lock mechanism is in the inactive condition. The annular bearing wall 41 is formed with an upper recess 42 and a lower recess 43 configured to accommodate a portion of the upper detent 36 and lower detent 37 respectively when the lock mechanism is in an active condition. This prevents retraction of the bolt 5 by rotation of the inner cam 32.

Figure 7 also illustrates a central projection 44 of the outer cam plate 19 (see also Figure 2), having a pair of opposed bores, with each bore accommodating a leg 79 of a lock release 80 (See Figure 2). The lock e member 80 forms part of lock release ism that is considered to be in a selected condition when the e member 80 is located with its legs 79 in the opposed bores of the outer cam plate 19. Rotation of the outer cam plate 19 causes either one of the legs 79 to engage a block 81 (see also Figure 11) on a rear surface of the drive member 33 to adjust the condition of the lock mechanism. For example, rotation of the outer cam plate 19 in an anti-clockwise ion from the position shown in Figure 7 will cause the lower leg 79 to engage the block 81 as illustrated in Figure 8. That rotation causes the drive member 33 to move to the left. This movement of the drive member 33 results in retraction of the lower detent 37 as a knob 45 (see Figure 7) on the lower detent 37 slides along the lower ramp e 39, whilst the upper detent 36 slides along the upper ramp surface 38 to move free of the upper recess 36. With the upper detent 37 and lower detent 37 in these positions the inner turn knob 8 (see Figure 1) is free to rotate to t the bolt 5, and the lock mechanism is considered to be in the inactive condition. It ought to be appreciated that on of the outer cam plate 19 in a clockwise direction from the position illustrated in figure 8, can result in the drive member 33 moving back to the right hand position as illustrated in figure 7.

Accordingly this allows the outer actuator 7 to operate to adjust the condition of the lock mechanism from an unlocked condition to a locked condition. (Prashanth please confirm this is the case that we can lock in the inner turn knob from the outside if desired) Referring now to Figure 9 which again illustrates the lock mechanism in the active condition similar to the arrangement illustrated in Figure 7, however illustrating the cylinder cam 40, interacting with the drive member 33. The upper detent 36 and lower detent 37 are d in the upper recess 42 and lower recess 43 respectively resulting from the location of the drive member 33 relative to inner bearing plate 27.

Figure 9 illustrates the surface formation 46 on the inner cam designed to interact with opposed abutments 47, 48 of the drive member 33, to adjust its position relative to the inner bearing plate 27. In contrast Figure 10 illustrates the cylinder cam 40 being rotated, by rotation of a barrel 49 (see Figure 2) of the inner er lock 50, by an riately coded key 51. This adjusts the position of the upper detent 36 and lower detent 37 relative to the upper recess 42 and lower recess 43 respectively. Once the upper detent 36 and lower detent 37 are in the position illustrated in Figure 10, the lock mechanism is considered to be in an inactive condition, whereby the inner actuator 6 (See Figure 1) is free to rotate to retract the bolt 5.

It is an aspect of the lock assembly 1 that the lock e mechanism be selectable whereby in a selected condition the outer actuator 7 can interact with the lock mechanism so that operation of the outer actuator 7 adjusts the ion of the lock mechanism from the active condition to the inactive condition, and when the lock release mechanism is in an unselected condition does not interact the operation of the outer actuator 7 with the lock mechanism. The preferred arrangement of this aspect is achieved by removing or adding the lock e member 80 from the lock assembly when the lock ly is being installed.

Where the lock assembly 1 is provided with the lock release member 80 attached to the outer cam plate 19, the outer cam plate 19 must be first detached from the backing plate 18 to gain access to the lock release member 80. It can be appreciated from Figure 13 that the outer cam plate 19 es a short shaft 89 which is locatable in the central aperture 17 of the backing plate 18. The central aperture is formed with a keyway 90 which is more clearly illustrated in Figure 16 that is shaped to odate a lug 91 on the shaft 89 when the outer cam plate 19 is oriented into a particular position relative to the backing plate 18. It ought to be iated that in all other orientations the lug 91 is not aligned with the keyway 90 and thereby the outer cam plate 19 is captured by the outer backing plate 18. When the outer cam plate 19 is detached from the backing plate 18 the lock release member 80 can be detached and thereby lock release mechanism is considered to be in an unselected condition. As a result, the legs 79 will be unable to interact with the block 81 (see also Figure 7).

When the lock release mechanism is in an unselected condition it is preferred that operation of the inner cylinder lock 50 be controlled so that removal of the key 51 from the inner cylinder lock 50 can only be ed once the lock mechanism is returned to the active condition. This on is achieved in the embodiment illustrated in Figure 13 by including a limiter 92(hereinafter ed to as a second limiter) in the form of a screw for attachment to the drive member 33. The screw 92 extends through the rear surface of the drive member 33 when the lock mechanism is in the active condition so as to be positioned adjacent a leg 93 of the inner cam 19 (see Figure 14). Figure 14 illustrates the drive member 33 with a portion of the rear surface f removed to reveal the leg 93. This arrangement can be also appreciated from Figure 15 where it can be noted that the screw 92 overlaps with an arc of movement of the leg 93. It should be noted that the key 51 can only be inserted and removed into the inner cylinder lock 50 when the leg 93 of the cylinder cam 40 is in the specific orientation illustrated in Figure 14. As this corresponds to the orientation whereby tumblers (not shown) in the inner er lock 50 are aligned to release the key 51. Furthermore, it should be appreciated that the orientation can only be achieved by returning the drive member 33 to the position as illustrated in Figure 14 which corresponds to the lock ism adopting the active ion.

Figure 12 also illustrates a screw 94 located between the backing plate 18 and furniture plate 95. The screw is intended for fastening in a threaded re 96 formed in the backing plate 18, which screw 94 can also be seen in Figure 16. When the screw 94 is attached to Figure 16 illustrates the backing plate 18 in this manner it acts as a r, hereinafter referred to as a first limiter, for ng the degree of rotation of the outer cam plate 19 relative to the backing plate 18. It can be appreciated from Figure 13 that the outer cam plate is formed with a shoulder 97 that interacts with the screw when attached to the backing plate 18, so as to prevent rotation of the outer cam in a clockwise direction.

The lock assembly as herein before described allows for the installer to select, on site, whether to activate a lock release function or not. The use of limiters to encourage the user operate the lock in a certain manner es further useful advantages.

Claims (23)

1. A lock assembly for use with a movable barrier, the lock assembly including a housing for oning on an inner side of the movable r which houses a bolt, the bolt being movable relative to the housing between an ed position and a retracted position, a first actuator that is operable by rotation about an actuation axis at an inner side of the housing to cause movement the bolt from the extended position towards the ted position, a lock mechanism within the housing that is adjustable between an active condition and an ve condition so that when in an active condition renders the first actuator inoperable and when in an inactive ion renders the first actuator operable, a second actuator le from an outer side of the housing to cause movement of the bolt from the extended position towards the retracted position, a lock release mechanism that is selectable so that when in a selected condition interacts the operation of the second actuator with the lock ism so that ion of the second actuator adjusts the condition of the lock ism from the active condition to an inactive condition, and when the lock release mechanism is in an unselected condition does not interact the operation of the second actuator with the lock mechanism.

2. A lock assembly according to claim 1 wherein the second actuator includes a rotatable member that is ble about the actuator axis to cause movement of the bolt from the extended position towards the retracted position, whereby the lock release mechanism includes a release member that is associated with the rotatable member when the lock release mechanism is in the selected condition.

3. A lock assembly according to claim 2 wherein the rotatable member is a cam that is rotatable about the actuation axis to cause liner movement of the bolt.

4. A lock assembly according to claim 3 wherein the bolt includes a bolt head and a bolt body with the bolt body formed with a shoulder, the cam being formed with a projection that engages the shoulder when moving the bolt.

5. A lock assembly according to claim 4 wherein the release member is positioned on the cam when the lock release mechanism is in the selected condition, and located in radially inwardly of the projection on the cam.

6. A lock assembly according to any one of claims 2 to 5 including a backing plate that is able with the housing, the backing plate being configured to accommodate the rotatable member so as to allow rotation relative thereto.

7. A lock ly according to claim 6 including a first limiter that is ated with the backing plate and interacts with the rotatable member to limit the extent of rotation of the rotatable member in one direction of rotation.

8. A lock mechanism according to claim 7 wherein the first limiter is in the form of a screw and the backing plate is configured with a threaded aperture so that the first r can be detachably fastened to the backing plate to selectively limit the extent of rotation of the rotatable member.

9. A lock assembly according to any one of the preceding claims wherein the lock ism includes a drive member that is movable within the g when the lock mechanism s between the inactive ion and the active condition, and at least one detent that is movable within the housing on movement of the drive member when the lock mechanism adjusts between the ve condition and the active condition, wherein the drive member and the at least one detent are configured to interact with each other so that movement of the drive member causes relative movement of the at least one detent.

10. A lock assembly according to claim 9 wherein the drive member includes an abutment that interacts with the lock release mechanism when the lock release mechanism is in the selected condition.

11. A lock assembly according to claim 9 or 10 including a first key ed cylinder lock that is operable from an inner side of the housing to adjust the condition of the lock mechanism.

12. A lock assembly according to claim 11 including a cylinder cam that is rotatable on operation of the first key operated cylinder lock and engages the drive member to move the drive member within the housing.

13. A lock assembly according to claim 12 including a second r that is associated with the drive member and interacts with the cylinder cam to limit the extent of rotation of the cylinder cam.

14. A lock assembly according to claim 13 wherein the second limiter interacts with the er cam and the drive member so as to permit a key ed into the first cylinder lock to be release only when the lock mechanism is in the active condition.

15. A lock ism according to claim 13 wherein the second limiter is in the form of a screw and the drive member is ured with a threaded aperture so that the second limiter can be detachably fastened to the drive member to selectively limit the extent of rotation of the cylinder cam.

16. A lock assembly according to any one of claims 9 to 15 wherein the at least one detent includes a first detent and a second detent that are each movable radially relative to the actuation axis.

17. A lock assembly according to claim 16 wherein the first detent is driven radially outwardly on movement of the drive member as the lock mechanism adjusts from the inactive condition to the active ion.

18. A lock assembly according to claim 16 or 17 wherein the second detent is driven radially outwardly on movement of the drive member as the lock ism adjusts from the inactive condition to the active condition, and driven radially inwardly on movement of the drive member as the lock mechanism adjusts from the active condition to the inactive condition.

19. A lock assembly according to any one of claims 9 to 18 wherein the drive member moves ly within the housing.

20. A lock ly according to any one of claims 11 to 19 wherein the second or includes a second key operated cylinder lock.

21. A lock assembly according to claim 20 n of the first key operated cylinder lock and or the second key operated cylinder lock are located relative to the actuation axis so that either or both are operable by rotating a key about the actuation axis.

22. A lock assembly according to any one of the preceding claims including a biasing means for biasing the bolt towards the extended position.

23. A lock assembly according to any one of the preceding claims wherein the lock assembly is a rim lock assembly and the bolt is a latch bolt.