[0001 ] This invention relates to a lock assembly for mounting to a door, including a bolt biased towards an extended position and at least an inner actuator, such as a turn knob or the like, for moving the bolt towards a retracted position. More specifically the lock assembly includes a retention means for selectively retaining the bolt in the retracted position. The lock assembly may take the form of a rim lock assembly having a housing which is suitable for mounting to a surface of a door or the like, and it will be convenient to hereinafter describe the invention with reference to this form of lock assembly. It should be appreciated however that the invention is suitable for other forms of lock assembly including a mortice lock assembly.

Background of Invention

[0002] 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 position to a retracted position. The bolt is movable on an inner side of the door generally by an inner turn knob or lever (hereinafter turn knob), and on an outer side of the door generally only by operating a key operated cylinder lock or the like.

[0003] The bolt may be in the form of a latch bolt which is urged towards an extended position under the action of a biasing spring. When the door is moved from an open position to a closed position, the latch bolt will automatically latch the door to hold it in a closed position. Opening the door from the inner side can be achieved by rotating the turn knob, and from the outer side by rotating the key in the cylinder lock. Where the door was closed unintentionally, thereby shutting the person outside the door, it can be frustrating have to find and use a key to reopen the door from the outside. Furthermore it can be problematic if the only key is on the inside of the door, which would result in the user being locked out. [0004] The applicant has appreciated that it can be desirable to produce a lock assembly that reduced the likelihood of users being unintentionally locked out.

[0005] 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 contains was part of the common general knowledge as at the priority date of any of the claims.

Summary of Invention

[0006] According to this invention there is provided a lock assembly for use with a door, the lock assembly including a housing, a bolt movable relative to the housing between an extended position and a retracted position, a bolt biasing means which urges the bolt to move towards the extended position, an inner actuator that is rotatable about an actuator axis by hand from an inner side of the door to move the bolt from the extended position towards the retracted position, a lock mechanism that is adjustable between an active condition and an inactive condition which renders the inner actuator inoperable and operable respectively, a retention means that when in an inoperable condition does not inhibit the movement of the bolt from the retracted position and when in an operable condition inhibits the movement of the bolt from the retracted position by the urging of the bolt biasing means while permitting the movement of the bolt from the retracted position towards the extended position on rotation of the inner actuator, a selector means that interacts with the retention means and is adjustable between a selected condition and an unselected condition in which the retention means is rendered inoperable and operable respectively.

[0007] The housing may take any suitable form which could include a unitary housing member or an assembly of housing members forming the housing. The housing is preferably configured for in use mounting to a surface of a door. The bolt may take any suitable form and one suitable form includes a latch bolt. The preferred form of latch bolt includes a leading face configured to, in use, slide over a ramp surface of a strike plate mounted on a door jamb when the door is closed. The leading face is preferably configured with a bevelled leading face, however other shapes such as a "bull nose" or hook leading face may also be suitable for swing and sliding doors respectively. The bolt biasing means may take any suitable form and one suitable form includes a biasing spring, and in particular a torsion spring. This form of spring may vary and could include an axial compression spring.

[0008] The retention means may directly or indirectly interact with the bolt to inhibit its movement from the retracted position. It is preferred that the interaction be indirect via the actuator, whereby the inner actuator is rotatable between a first position and a second position which corresponds with the bolt adopting the extended position and retracted position respectively, whereby the retention means when in the operable condition interacts with the inner actuator when the inner actuator has been rotated to the second position so as to inhibit rotation of the inner actuator to the first position. The lock assembly may also include an actuator biasing means for urging the inner actuator towards the first position. When the retention means is in an operable condition it is preferred that it applies a retention force to the inner actuator that exceeds an actuator biasing force being produced by the actuator biasing means. Furthermore where the bolt biasing means applies a bolt biasing force which combines with the actuator biasing force urging the inner actuator towards the first position, it is preferred that the retention force when the retention means is in the operable condition exceeds the combination of the bolt biasing force and the actuator biasing force. It is however preferred that the retention force be limited to still allow the user to rotate the inner actuator back to the first position, even while the retention means is in the operable condition.

[0009] The retention means may take any suitable form and in one form includes a retention member that pivots about a retention axis when the retention means adjusts between the operable condition and the inoperable condition. It is further preferred that retention member includes a projection and the inner actuator includes a shoulder that engages with the projection when the retention means is in the operable condition and does not engage with the projection when the retention means is in the inoperable condition. It is still further preferred that the retention member has a fixed end proximate the retention axis and a free end spaced from the retention axis with the projection being located at or near the free end. It is still further preferred that the retention member is formed from a resilient material however this may vary. Alternatively the retention member may be relatively rigid and the retention means includes a biasing member acting on the retention member. In either arrangement it is preferred that the projection be urged towards or away from engagement with the shoulder.

[0010] The selector means may take any suitable form and in one form includes a selector member that pivots about a selector axis when the selector means adjusts between the selected condition and the unselected condition. The selector member may move in a manner other than pivoting, such as moving axially, and pivoting is merely one option for movement of the selector member. It is preferred that the selector member be inhibited from freely adjusting its position, so as to reduce the likelihood of the selector means inadvertently adjusting between the selected condition and the unselected condition. The preferred arrangement includes the selector member being movable in the direction of the selector axis to move between a fixed position and a pivotable position, whereby the selector member must be in the pivotable position in order to adjust the selector means between the selected condition and the unselected condition, and the selector means includes a selector biasing member for biasing the selector member towards the fixed position. This arrangement however may vary, particularly depending upon the manner in which the selector member moves to adjust the condition of the selection means. The selector member preferably includes a cam surface that engages the retention means when the retention means is in the inoperable condition, however this will vary depending upon the direction in which the projection on the retention member is urged.

[001 1 ] The lock mechanism preferably includes at least one detent member that is movable relative to the inner actuator on adjustment of the lock mechanism between the active condition and the inactive condition.. The lock mechanism may directly prevente rotation of the inner actuator, or indirectly prevent movement of the bolt within the housing to render the inner actuator inoperable.

[0012] The lock assembly may include any form of coded interface for adjusting the condition lock mechanism. The preferred form of interface includes a first key operated lock operable from an inner side of the housing for adjusting the condition of the lock mechanism between the active condition and the inactive condition. However alternatively the lock mechanism may interact with a key pad or an electronic key reader. The preferred embodiment of the key operated lock is a cylinder lock, including a casing and a barrel movable relative to the casing when a correctly coded key is inserted in a keyway of the barrel. It is still further preferred that the barrel is movable by rotating relative to the casing, however the barrel may alternatively move in an axial direction relative to the casing on insertion of the key.

[0013] The lock assembly preferably includes an outer actuator that is operable from an outer side of the housing to move the bolt from the extended position towards the retracted position. It is further preferred that the outer actuator is operable to adjust the condition of the lock mechanism between the active condition and the inactive condition. The outer actuator may take any suitable form, including a key pad or an electronic card reader, however it is preferred that the outer actuator is a second key operated lock. It is further preferred that the second key operated lock is a cylinder lock, including a casing and a barrel movable relative to the casing when a correctly coded key is inserted in a keyway of the barrel. The barrel is preferably movable by rotating relative to the casing, however alternatively the barrel may move axially relative to the casing.

[0014] The lock mechanism preferably includes at least one detent member that is movable relative to the inner actuator on adjustment of the lock mechanism between the active condition and the inactive condition. In the preferred embodiment the lock mechanism includes two detents however this may vary. It is preferred that the inner actuator is operable by rotation about an axis, and the detent, or each detent, is movable in a radial direction relative to the axis. It is preferred that the lock mechanism includes a drive member that interacts with the at least one detent and is movable relative to the housing on adjustment of the lock mechanism between the active condition and the inactive condition. Whilst the preferred embodiment of the lock assembly includes the drive member moving linearly to adjust the position of the detent(s), the drive member may move in some other manner. The drive member may, for example, rotate to adjust the position of the detent(s). [0015] While the lock assembly according to the invention includes a retention means to selectively inhibit movement of the bolt from the retracted position, it is preferred that the lock assembly also be configured to selectively lock the bolt in the retracted position. The lock assembly may be configured in any suitable manner to achieve this however it is preferred that the housing includes a further relatively fixed part that is engaged by the at least one detent when the inner actuator has been rotated to move the bolt to the retracted position and the lock mechanism is adjusted to the active condition so as to lock the bolt in the retracted position.

[0016] It is further preferred that at least one detent include two detents on opposed sides of the inner actuator.

[0017] It is still further preferred that the bolt includes a bevelled face.

[0018] The preferred embodiment of the lock assembly is a rim lock assembly, however the invention may also apply to other forms of lock assembly.

[0019] 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 various features, as described and illustrated is not to be understood as limiting on the invention.

Brief Description of Drawings

[0020] Figure 1 is a diagrammatic isometric view of a preferred embodiment of the lock assembly when installed according to this invention.

[0021 ] Figure 2 is an exploded isometric view of a preferred embodiment of the lock assembly according to the invention.

[0022] 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.

[0023] Figure 4 is a rear elevation view of the lock assembly from Figure 3 with the bolt moved to retracted a position on operation of the outer cam. [0024] Figure 5 is a rear elevation view of the lock assembly with the backing plate removed to reveal the bolt in an extended position.

[0025] 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.

[0026] Figure 7 is a rear elevation view of the lock assembly with the backing plate and bolt removed to reveal the lock mechanism in an active condition.

[0027] Figure 8 is a rear elevation view of the lock assembly from Figure 7 with the lock mechanism having been adjusted by the outer cam to adopt an inactive condition.

[0028] 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.

[0029] Figure 10 is a rear elevation view of the lock assembly from Figure 9 with the lock mechanism having been adjusted to an inactive condition on operation of a cylinder cam.

[0030] Figure 1 1 is a cross-sectional view through XI-XI of Figure 9.

[0031 ] Figure 12 is a cross-sectional view through XII-XII of Figure 1 1 .

[0032] Figure 13 is a cross-sectional view of Figure 1 1 with the indicator member being tampered with.

[0033] Figure 14 is a rear elevation view of the lock assembly with at least the backing plate removed and the latch frame illustrated as transparent to show the bolt in the extended position and a retention means in an inoperable condition.

[0034] Figure 15 is a rear elevation view of the lock assembly from Figure 14 with the inner actuator rotated to retract the bolt.

[0035] Figure 16 is a rear elevation view of the lock assembly from Figure 14 with the retention means in an operable condition.

[0036] Figure 17 is a rear elevation view of the lock assembly from Figure 16 with the inner actuator rotated to retract the bolt, and retained in this position by interacting with the retention means.

Detailed Description

[0037] 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 adjacent a free edge 4 of the door 2. The look 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 capable of interacting with a strike (not shown) which in use is fixed on a door jam (not shown) for retaining the door 2 in a closed position.

[0038] 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 position 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 substituted 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 1 1 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.

[0039] 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 example on the turn knob 8, the function of the aperture is to provide a viewing window through which an indicator member 14 (see Figure 2) can be made visible. The manner in which the indicator member achieves this will be described in greater detail with reference to later illustrations.

[0040] Referring now to Figure 2, which illustrates a specific form of the outer actuator 7 including the cylinder lock casing 1 1 with a tumbler bible 15 orientated substantially vertically. A tail bar 16 is positioned to engage with a barrel 10 of the cylinder lock 1 1 . 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 aperture 17 formed in a backing 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.

[0041 ] It should be noted from Figure 2 that the outer cam 19 includes an axially extending 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 removed. 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 positioned adjacent the projection 20. When comparing Figures 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 results in movement of the bolt 5 to the retracted position against the urging of the bolt torsion spring 24. The bolt 5 is considered to be in a retracted position when the bolt head 22 is within the housing 3.

[0042] The assembly and operation of the inner actuator 6 will now be explained firstly with reference to Figure 2. The inner actuator 6 includes 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 housing 3, and are secured in this position by four screws 28 which locate in appropriately spaced apertures 29, 30 formed in the inner bearing plate 27 and outer bearing plate 26 respectively. The finger grip element 25 is formed with screw flutes 78 (see Figure 1 1 ) 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 27.

[0043] 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.

[0044] 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 position 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 extended position illustrated in Figure 5 to the retracted position illustrated in Figure 6.

[0045] The lock assembly 1 according to the invention includes a lock mechanism, that when in an active condition the inner actuator is rendered inoperable for retracting the latch bolt 5 from the extended position. The preferred elements of and method for achieving 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 includes 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 clearly illustrated in Figures 7 to 1 1 .

[0046] 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 annular 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.

[0047] 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 release member 80 forms part of lock release mechanism that is considered to be in a selected condition when the release 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 1 1 ) 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 direction 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 surface 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 retract the bolt 5, and the lock mechanism is considered to be in the inactive condition. It ought to be appreciated that rotation 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.

[0048] 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 rather than the outer cam 19, interacting with the drive member 33. The upper detent 36 and lower detent 37 are located 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 1 ) of the inner cylinder lock 50, by an appropriately 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.

[0049] Referring now again to Figure 2 which illustrates the rectangular shaped aperture 13 in the housing 3 through which the indicator member 14 is visible when the lock mechanism is in an active condition. When the lock assembly 1 is assembled, the aperture 13 is occupied by a transparent window 52. The indicator member 14 forms part of an indicator mechanism which also includes a shuttle 53. The indicator member 14 and shuttle 53 are each biased in opposite directions by an indicator biasing spring 54 and a shuttle spring 55 respectively. Figure 1 1 illustrates the lock assembly in cross section with the lock mechanism in the active condition. When the lock mechanism is in this active condition, the indicator member 14 is positioned over the aperture 13 so as to be visible therethrough. The indicator member 14 is urged towards this position by an indicator biasing spring 54. Figure 1 1 also illustrates the drive member 33 including a nose portion 56 abutting the shuttle 53. The shuttle 33 is retained in a right-hand position compressing the shuttle spring 55. [0050] In contrast Figure 12 illustrates the lock mechanism in the inactive condition. It can be seen in Figure 12 that the indicator member 14 has been moved laterally relative to the aperture 13 so as to no longer be visible therethrough. This is achieved by the shuttle 53 being biased towards a left-hand position by the shuttle biasing means 55, once the drive member 33 has been moved from the position illustrated in Figure 1 1 to the position as illustrated in Figure 12. The shuttle biasing spring 55 is capable of applying a force to the shuttle 53, and indirectly to the indicator member 14 which is greater than the force applied by the indicator biasing spring 54 to the indicator member 14.

[0051 ] Figures 1 1 and 12 also illustrate a ball detent acting between the drive member 33 and the inner bearing plate 27. The force produced by the ball detent 57 is greater than the force acting on the shuttle 53 from the shuttle spring 55 so as to prevent movement of the drive member 33 under the influence of the shuttle spring 55.

[0052] Referring now to Figure 13, which illustrates the lock assembly 1 in cross-section with the lock mechanism in an active condition. The drive member 33 is in the right-hand position moving the shuttle 53 to compress the shuttle spring 55. The indicator member 14 however is being tampered with by, for example, a screw driver 58 or the like. However it can be appreciated from Figure 13 that movement of the indicator member 14 in this manner does not result in adjustment of the lock mechanism from the active condition. Instead the indicator member 14 separates from the shuttle 53 without adjusting the position of the drive member 33.

[0053] The lock assembly 1 according to the invention includes a retention means 59 that when in an inoperable condition does not inhibit movement of the bolt 5 from the retracted position, and when in an operable condition inhibits the movement of the bolt 5 from the retracted position by the urging of the bolt biasing means 24 while permitting the movement of the bolt 5 from the retracted position towards the extended position on rotation of the inner actuator 6. The retention means 59 may take any suitable form, and the figures show one suitable form. Referring again now to Figure 2, which illustrates a preferred embodiment of the retention means 59 that includes a retention member 60 pivotable about a retention axis Y-Y.

[0054] The lock assembly 1 according to the invention also includes a selector means 61 that interacts with the retention means 59 which is adjustable between a selected condition and an under-selected condition in which the retention means 59 is rendered inoperable and operable respectively. The selector means 61 may take any suitable form, and Figure 2, illustrates a preferred form of selector means 61 suitable for the invention. The selector means illustrated in Figure 2 includes a selector member 62 that is pivotable about a selector axis Z-Z, when the selector means adjusts between the selected condition and the unselected condition.

[0055] Figure 2, also illustrates an intermediate frame member 63 which is fixable relative to the housing 3. The intermediate frame member 63 includes a pair of spaced upstanding legs 64 which are positionable in use adjacent a rear surface (obscured) of a side edge 65 of the housing 3, and fixable in that position by way of a pair of screws 66. The intermediate frame member 63 is formed with an oblong shaped aperture 67 in an upper corner thereof which is shaped to interact with the selector member 62. The aperture 67 includes a substantially circular central portion which is shaped to receive a head portion 68 of the selector member 62 therein. The aperture also includes a pair of opposed semi-circular portions, on opposed sides of the central circular portion, which are shaped to interact with a projection 68 (see Figure 14), formed adjacent the head 68 of the selector member 62. The selector means 61 also includes a selector biasing means 70 which in the embodiment illustrated in Figure 2, is in the form of a coil compression spring which urges the selector member 62 towards the intermediate frame member 63, for reasons which will be explained with reference to Figures 14 to 17.

[0056] Figure 2, also illustrates an actuator biasing means 71 , in the preferred form of a torsion spring which urges the inner actuator 6 towards the first position. As explained previously this generally corresponds with the bolt 5 being located in the extended position. It ought to be appreciated that the interaction of the inner actuator 6 with the bolt 5, and in particular the actuator biasing means 71 with the bolt biasing means 24 is such that the bolt biasing means 24 and the actuator biasing means 71 combine to urge the inner actuator 6 towards adopting the first position (see Figure 14).

[0057] Referring now to Figure 14, which illustrates the lock assembly 1 with the bolt 5 in the extended position and the inner actuator 6, or the inner cam 32 forming part of the inner actuator 6, in the first position. The inner cam 32 is formed with a shoulder 72 (see also Figure 2), which is illustrated slightly clockwise of a 12 o' clock position. In contrast Figure 15, illustrates the inner actuator 6 having been rotated to the second position, to thereby more the bolt 5 to the retracted position, and it can be noted that the shoulder 72 on the inner actuator 6 has been rotated in the anti-clockwise direction to just clockwise of a 9 o'clock position. It ought to be appreciated that by comparing Figures 14 and 15, that the inner actuator 6 is free to rotate between the first position and the second position to move the bolt 5 between the extended position and the retracted position respectively. More specifically the shoulder 72 on the inner actuator 6 is not inhibited in its movement by the retention member 60. Figures 14 and 15, illustrate the retention means 59 in an inoperable condition. This is achieved by a cam surface 73 on the selector member 62 engaging a free end 74 of the retention member 60 to move a projection 75 on the retention member 60 out of the path of movement of the shoulder 72 of the inner actuator 6. The selector member 62 is retained in the position illustrated in Figures 14 and 15, by the projection 69 adjacent the head 68 of the selector member 62 locating in a left-hand semicircular portion of the oblong aperture 67 in the intermediate frame member 63.

[0058] Referring now to Figure 16, whereby the selector member 62 has been rotated through 180° so that the projection 69 on the head 68 is keyed into a right- hand semi-circular portion of the oblong aperture 67. The head 68 of the selector member 62 must first be depressed against the action of the selector biasing means 70 (see also Figure 2), to dislodge the projection 69 from the oblong aperture 67 before this rotation can occur. It ought to be appreciated from Figure 16, that this rotation of the selector member 62 disengages the cam surface 73 from the free end 74 of the retention member 60, and with the retention member 60 biased it will rotate about the retention axis Y-Y towards the inner actuator 6. This now locates the projection 75 on the retention member 60 in the path of movement of the shoulder 72 on the inner actuator 6 so that as the inner actuator 6 is rotated from the first position illustrated in Figure 16, to the second position as illustrated in Figure 17, the shoulder 72 on the inner actuator 6 locates behind the projection 75 on the retention member 60. As the inner actuator 6 is retained in this second position, this in turn retains the bolt 5 in the retracted position against the operation of the bolt torsion spring 24, and actuator biasing means 71 (see Figure 2).

[0059] It is preferred however, that the shoulder 72 on the inner actuator 6 and projection 75 on the retention member 60 interact in such a manner so, notwithstanding the retention means 59 being in an operable condition, a user may apply sufficient force to the inner actuator 6 to rotate the inner actuator 6 from the second position illustrated in Figure 17, to the first position illustrated in Figure 16. In the embodiment illustrated in Figures 16 and 17, this is achieved as a result of relatively curved surfaces on the projection 75 of the retention member 60 and shoulder 72 on the inner actuator 6. In conjunction with a biasing force produced by the coil spring 76 formed at the fixed end of the retention member 60. Whilst it is preferred that the retention member 60 is formed from a resilient material a separate biasing means may be included to urge the retention member 60. However, this functionality may be achieved by other means.

[0060] If the user needs to do more than just inhibit movement of the bolt 5 from the retract position, the inner actuator 6 can be locked in the second position. It can be noted from the lock assembly illustrated in Figure 14, or more clearly illustrated in Figures 7 and 8, that the housing includes a side recess 77 formed in a relatively fixed part of the housing 3 which can be engaged by the upper detent 36 when the inner actuator is rotated to the second position, and when the lock mechanism is adjusted to the active condition. It ought to be appreciated that when the lock assembly is in this condition rotation of the inner actuator 6 is prevented, and thereby movement of the bolt 5 from the retracted position to the extended position is also prevented.

[0061 ] It ought to be appreciated from the foregoing that the lock assembly 1 as hereinbefore described provides a useful option for the lock installer to select whether a retention function is operable or inoperable when installing the lock. Furthermore, the ability of the user to override the retention means 59, without having to adjust the condition of the lock mechanism is a further advantage.

[0062] Various alteration and/or additions may be introduced into the lock assembly as hereinbefore described without departing from the spirit or amber of the invention.