GB2606808A

GB2606808A - Lock mechanism and method of operation

Info

Publication number: GB2606808A
Application number: GB2201587.9A
Authority: GB
Inventors: Fletcher Tracy; Ranue Nachhatter
Original assignee: Spire Manufacturing Ltd
Current assignee: Spire Manufacturing Ltd
Priority date: 2021-02-08
Filing date: 2022-02-08
Publication date: 2022-11-23
Also published as: GB202101710D0

Abstract

A lock mechanism comprising a linear drive bar moved by rotating drive socket of a handle; a locking unit which comprising a locking element, such as a vee block 60, biased to locking position which prevents movement of drive bar (24) preferably protrusion 56 engages in recess 58 of drive bar. A retainer 80 moves, e.g. pivots, between a retaining position in which it retains the locking element 60 in unlocked position disengaged from drive bar and a releasing position in which it is releases the locking element to automatically lock the drive bar. The retainer is biased toward the retaining position but is released by a releasing element 90, the releasing element may be a sliding rod coupled to a spring biased rack element of drive socket. Unlatching the door may prime the locking unit ready to automatically deadlock the drive bar upon subsequent movement of the drive bar to locked position by the handle at which point the recess 58 and protrusion align. The locking element may be retracted by a cam lug 62 of a cylinder lock.

Description

LOCK MECHANISM AND METHOD OF OPERATION

FIELD OF THE INVENTION

The invention relates to a lock mechanism and to a method of operation of the lock mechanism.

The invention is expected to have its greatest utility in relation to a lock mechanism 10 for a door and the following description will relate primarily to that application. The invention is nevertheless not limited by the application for which the lock mechanism is to be used.

Directional and orientational terms such as "top'', "bottom', "upwards' etc. refer to 15 the lock mechanism oriented as shown in Fig.1, which is a typical orientation when mounted to the vertical edge of a door. The lock mechanism is not, however, limited to that orientation.

BACKGROUND TO THE INVENTION

A door has a closed condition within its surrounding frame, with only a small air gap between the door and frame. A lock mechanism is provided to secure and lock the door in the closed condition. In practice, the air gap between the door and its frame is typically sealed by resilient seals fitted to the door and/or frame and operation of the lock mechanism acts to compress the seal(s) to minimise the likelihood of draughts when the door is closed.

The door can be secured and locked in its closed condition at one position (single 30 point locking) or at more than one position (multi-point locking). Many known lock mechanisms can actuate multi-point locking elements simultaneously.

Many doors have a largely hollow profile defining their outer edge. It is common to mount some or all of the locking componentry, including the lock mechanism, in the hollow profile, especially in the case of multi-point locking arrangements.

One known type of lock mechanism is an espagnolette lock mechanism. An espagnolette lock mechanism has a housing containing one or two drive bars, the drive bars being driven to move by way of an operating handle connected to the lock mechanism. The drive bar(s) can be connected to one or two locking bars which extend beyond the housing and which are mounted to move along the locking edge of the door. The locking bar(s) can carry one or more locking elements or bolts which also move along the locking edge and, when the door is closed, into and out of engagement with keepers mounted to the frame. An espagnolette lock mechanism with a drive bar connected to a single locking bar is disclosed in GB 2 072 740. In common with other similar arrangements the locking bar carries a plurality of locking bolts. Each of the locking bolts can be made more secure by having an enlarged head locatable into an undercut-keeper, such as the locking bolts of GB 2 161 208.

The espagnolette lock mechanism of GB 2 072 740 has a single drive bar which is connected to a single locking bar. The locking bar is driven to move in a first direction to secure the locking bolts and is driven in a second (opposing) direction to release the locking bolts. Other espagnolette lock mechanisms have two drive bars which move in opposing directions, and which can be connected to two separate locking bars. In such arrangements both of the locking bars can be driven to move towards (or away from) the housing to secure the locking bolts, and both can be driven to move away from (or towards) the housing to release the locking bolts.

A variant of this latter arrangement takes advantage of the opposing movement of the drive bars by connecting them to shoot bolts which can project beyond the 30 corners of the door (i.e. beyond the ends of the locking edge) to provide additional security.

An espagnolette lock mechanism utilising two oppositely-movable drive bars, and which is suitable for use with a multi-point locking arrangement, is disclosed in GB 2 297 796.

An espagnolette lock mechanism will typically have a drive socket of square section which is designed to accommodate the square-section shaft connected to the operating handle. The housing of an espagnolette lock mechanism is often referred to as a gearbox because the componentry in the housing converts rotary movement of the operating handle into linear movement of the drive bar(s) (and consequently linear movement of the locking bar(s) and/or shoot bolts). An espagnolette lock mechanism will typically also have a key-operated lock so that the drive bar(s) (and therefore also the locking bar(s) and/or shoot bolts) can be locked in their secured position.

For ease of understanding and unless otherwise indicated, the verb "secure" (and derivations thereof) will be used herein to identify the situation in which the lock mechanism has been actuated and the locking bolt or bolts are able to engage their respective keepers, and the verb "lock" (and derivations thereof) will be used to identify the situation in which the lock mechanism has been actuated and the insertion and rotation of a key in the key-operated lock is required to release (disengage) the locking bolt(s).

The detailed form of the hollow profile of each door manufacturer will typically be unique to that manufacturer. However, industry standards have been established so that the manufacturers of locking componentry can make their componentry suitable for fitment to the doors of different manufacturers. In particular, the hollow profile will typically include a "Euro-groove'', which is a groove of standard width and depth and which is open to the exterior of the profile. The manufacturer of locking componentry can make it suitable for fitment into the Euro-groove in the knowledge that it will fit a wide range of doors. The housings of most espagnolette lock mechanisms in particular are manufactured to have standard cross-sectional dimensions so that the housing can fit into the Euro-groove.

The lock mechanism will typically have other standard features, for example the size and location of the drive socket will typically be fixed in relation to the fixing holes for the operating handle, so that the operating handles of many different manufacturers can be used with a particular lock mechanism.

Also, the key-operated locks which are typically fitted to an espagnolette lock mechanism are usually of standardised form, typically a "Euro-cylinder". The lock mechanism manufacturer will therefore typically provide the lock housing with an opening to receive a Euro-cylinder lock, and will mount componentry into the housing to cooperate with the (standardised) tumbler or drive member of the Eurocylinder lock. The installer can therefore choose to fit a particular Euro-cylinder lock having the desired length and security features.

In most espagnolette lock mechanisms the rotation of the drive socket causes linear movement of a drive bar inside the gearbox. If the lock mechanism has two oppositely-movable drive bars the lock mechanism will also contain componentry to covert linear movement of the first drive bar in a first direction into linear movement of the second drive bar in a second (opposing) direction.

The particular application for which the lock mechanism is designed will largely determine the componentry of the lock mechanism. For example, some lock mechanisms also include a spring-biased latch, and some also include a mortice bolt or a hook bolt. In many of the known espagnolette lock mechanisms the mortice bolt or hook bolt is actuated by movement of a drive bar.

A door to which an espagnolette lock mechanism is fitted will typically have an operating handle fitted to both sides of the door and a key-operated lock into which a key can be inserted from at least the outside of the door. Some locks allow the key to be inserted also from inside the door, whilst others have a paddle or thumb-turn by which lock may be actuated from inside the door without insertion of the key. In either case the lock mechanism can be locked and unlocked from both sides of the door, and the operating handle at each side of the door can typically be used to move the lock mechanism between its secured and unsecured conditions.

For ease of understanding, an espagnolette lock mechanism or gearbox is shown in Fig.1. Whilst the known espagnolette lock mechanisms differ in detail, many general features are shared. The shared general features which are relevant to the present invention are described below for the purposes of providing background information.

The lock mechanism 10 has many features which are effectively standardised. The depth D of the housing 12, and also the thickness of the housing (i.e. in the direction into and out of the page as seen) permit the housing 12 to fit into the Euro-groove of a door profile. The length of the housing 12 (i.e. from the top of the page to the bottom of the page as drawn) is not standardised; the Euro-groove extends along the locking edge of the door and the housing 12 can occupy whatever length of the profile is required.

The wall of the housing 12 has been removed so that componentry of the lock mechanism 10 is visible. The lock mechanism has a drive socket 14 comprising an opening through the housing 12, the drive socket being of square-section and designed to accommodate the square-section drive shaft connected to a conventional operating handle (not shown). A follower 16 is connected to the drive socket 14 and generally rotates with the drive socket.

A drive cam 20 is also connected to the drive socket 14 and generally rotates with the drive socket. The drive cam 20 is better seen in Figs. 5-8. A drive peg 22 (Fig.5) connects the drive cam 20 to a first drive bar 24. The first drive bar 24 extends above and below the drive cam 20 as drawn, is mounted to slide linearly in the housing (towards the top and bottom of the page as drawn in Fig.1), and has a primary rack 26. The primary rack 26 is engaged by a pinion 28, which pinion also engages a secondary rack 30 of a second drive bar 32. The second drive bar 32 is also mounted to slide linearly in the housing 12 (towards the top and bottom of the page as drawn in Fig.1). Accordingly, and in known fashion, rotary movement of the operating handle (typically through approximately 90°) is converted into linear movement of the first drive bar 24 in a first direction, which linear movement is (by way of the pinion 28) converted into linear movement of the second drive bar 32 in a second (opposing) direction.

When installed into a door, the first and second drive bars 24, 32 will typically be connected to locking bars and/or shoot bolts (not shown, but which extend beyond the housing 12), which can thereby be driven to move linearly along the locking edge of the door. The drive bars 24, 32 have connectors 34 for connection to the respective locking bars and/or shoot bolts.

in In this example, the lock mechanism 10 also includes a spring-biased latch 36 and a hook bolt 40.

The latch 36 is biased to the extended position as shown in Fig.1 by a spring (not shown). A shoulder of the latch body is engaged by the tongue 42 of the follower 15 16. Accordingly, anticlockwise rotation of the operating handle and follower 16 cause the latch 36 to be withdrawn into the housing 12.

It will be seen that the drive socket 14 has a drive member 44 which lies within an arc-shaped recess of the follower 16. The circumferential length of the arc-shaped recess is larger than that of the drive member 44 so that there is some lost motion between the drive member 44 and follower 16. The lost motion enables the operating handle to rotate partially without also rotating the follower 16, as described below.

In addition, it will be seen from Figs. 5-8 that the drive member 44 also lies within an arc-shaped recess of the drive cam 20. The circumferential length of the arc-shaped recess of the drive cam is also larger than that of the drive member 44 so that there is some lost motion between the drive member 44 and drive cam 20. The lost motion enables the operating handle to rotate partially without also rotating the drive cam 20, as described below.

The hook bolt 40 is mounted to the housing 12 by way of a fixed peg 48, the hook bolt 40 pivoting around the peg 48 as it moves between its extended position (as drawn in Fig.1) and its retracted position. The peg 48 is also located in a slot 50 of a latch link 52. Another peg 54 is mounted to the first drive bar 24 and is located in a slot of the hook bolt 40. From the position drawn in Fig.1, upwards linear movement of the first drive bar 24 and its peg 54 firstly causes the peg 54 to move along the slot of the hook bolt 40 and secondly (when the peg 54 reaches the top end of the slot) to cause the hook bolt 40 to pivot about the peg 48, specifically between the extended (secured) position as shown and a retracted (unsecured) position in which more (and perhaps all) of the hook bolt 40 is located inside the housing 12.

It will be understood that the first and second drive bars 24, 32 (and consequently the locking bars and/or shoot bolts connected thereto) and the hook bolt 40 are all interconnected to move together. To lock the mechanism 10 it is only necessary to prevent the movement of one of the linked components in order to prevent the movement of all of the linked components. In the lock mechanism 10 of Fig.1 locking is achieved by a locking projection 56 which can slide into a recess 58 (see Figs.3 and 4) of the first drive bar 24 (the recess 58 cannot be seen in Fig.1 because it is fully occupied by the locking projection 56). When the locking projection 56 is located in the recess 58 as shown in Fig.1 the first drive bar 24 cannot be moved upwardly, the hook bolt 40 cannot be withdrawn, and the second drive bar 32 cannot move downwardly. The locking bars or shoot bolts which are connected to the drive bars 24, 32 are therefore also locked.

The locking projection 56 is a part of a locking element or vee-block 60. The vee25 block 60 is mounted to slide linearly across the housing 12 (to the left as viewed in Fig.1), whereby the locking projection 56 leaves the recess 58 and the lock mechanism 10 is unlocked.

The vee-block 60 is driven to slide between its locking and unlocking positions by 30 rotation of the tumbler 62 of the Euro-cylinder lock (the tumbler 62 is shown in Figs. 2-4). It will be understood that as the tumbler 62 rotates anticlockwise as viewed in Fig.1 it will engage the edge 64 and move the vee-block 60 to the left.

The key-operated Euro-cylinder lock is not shown in Fig.1 but occupies the opening 66 in known fashion.

In the lock mechanism of Fig.1 the key-operated Euro-profile lock can also retract 5 the latch 36. The latch link 52 has an end part 68 which can be engaged by the tumbler 62. It will be understood that when the tumbler 62 rotates anticlockwise and engages the end part 68, the latch link 52 is driven upwardly in the housing 12. The upper end of the latch link 52 is pivotably connected to the follower 16 and upwards movement of the latch link 52 causes the follower 16 to rotate 10 anticlockwise and retract the latch 36. The lost motion between the follower 16 and the drive member 44 allows the follower 16 to rotate without causing corresponding rotation of the drive socket 14 or operating handle. The latch 36 can therefore be released (typically from outside the door) by insertion and rotation of the correct key.

The drive socket 14 also carries a pinion (not seen) which engages a rack 70, only part of which is visible in Fig.1. The rack 70 is part of a biasing bar 72 which is guided to move linearly upwards and downwards. The biasing bar 72 is spring-biased to a central position as shown and is connected to the operating handle by way of the rack and pinion with little or no lost motion. The biasing bar 72 acts to return the drive socket (and thereby the operating handle) to a neutral position (in which the operating handle is typically substantially horizontal) when released by the user. The lost motion provided for the drive member 44 in the respective arc-shaped recesses of the follower 16 and the drive cam 20 enable the biasing bar 72 to drive the operating handle back to its neutral position as drawn in Fig.1 without actuating any of the locking componentry.

Accordingly, the espagnolette lock mechanism 10 can be moved between its secured and unsecured positions by way of an operating handle connected to the drive socket 14 and the corresponding movement of the drive bars 24,32. The lock mechanism 10 can also be locked and unlocked by rotation of a key and the corresponding movement of the vee-block 60. Whilst these are general features of many espagnolette locking mechanisms, other espagnolette locking mechanisms do not have a latch and/or do not have a bolt, and/or have a linear bolt rather than a hook bolt, and/or have more than one bolt, with corresponding changes to their detailed componentry.

In most espagnolette lock mechanisms the vee-block (60) has a detent mechanism to seek to prevent unauthorised movement of the vee-block, in particular away from its locking position. Insertion and rotation of the correct key is required to overcome the detent.

SUMMARY OF THE INVENTION

The inventors have sought to provide a lock mechanism which shares many of the features of the known lock mechanisms described above and which includes all of 15 the practical benefits of that lock mechanism but which can be locked without insertion and rotation of the key.

According to the invention therefore, there is provided a lock mechanism having: a housing; a drive socket configured for connection to an operating handle; a drive bar in the housing, the drive socket being connected to the drive bar whereby rotation of the drive socket can be converted into linear movement of the drive bar; the housing having an opening to accommodate a key-operated Euro-cylinder lock; a locking unit within the housing, the locking unit including: a locking element which is located adjacent to the opening, the locking element being configured for engagement by a tumbler of an installed Eurocylinder lock, the locking element being movable between a locking position and an unlocking position, the locking element in the locking position engaging the drive bar to limit movement of the drive bar, the locking element being resiliently biased to its locking position; a retainer which is movable between a retaining position and a releasing position, the retainer in its retaining position being able to hold the locking element in its unlocking position, the retainer being resiliently-biased to its retaining position, the retainer being movable from its retaining position to its releasing position by a releasing element.

Accordingly, whereas with a conventional lock mechanism it is necessary to rotate 5 the Euro-cylinder lock (by way of a key from the outside or by way of a key or thumb turn from the inside) with the present invention the lock mechanism can be locked automatically (by way of the releasing element). This avoids the requirement to insert and rotate the key when locking the door from the outside (and from the inside if the key is required to actuate the lock mechanism from inside of the door). With 10 the present invention therefore the key is only required when it is desired to unlock the mechanism and the door.

Desirably, the retainer pivots between its retaining and releasing positions. Preferably the retainer pivots upon a fixed component in the housing, ideally a pivot 15 beam.

Preferably, the retainer has a retainer nose which cooperates with a retainer tab of the locking element, the retainer nose engaging an edge (and in particular a side edge) of the retainer tab in the retaining position.

Desirably the releasing element is slidably mounted in the housing. Preferably the releasing element can engage the retainer and release the retainer nose from the edge of the retainer tab. Preferably the releasing element is moved to engage the retainer by rotation of the drive socket. Accordingly, the operating handle can thereby be used to lock the mechanism.

Preferably, the lock mechanism has a biasing bar connected to the drive socket. Desirably the releasing element is engageable by the biasing bar. A biasing bar is a known component of espagnolette locking mechanisms such as that shown in Fig.1 and described above. The modification required to add such a releasing element is minimised and the mechanical complexity of the invented lock mechanism is also minimised.

Preferably, the releasing element is not connected to the biasing bar but is located to abut the end of the biasing bar. Accordingly, movement of the biasing bar in a first direction can abut and move the releasing element whereas movement of the biasing bar in a second opposing direction causes no corresponding movement of the releasing element. It is arranged that the first direction of movement of the releasing element is the direction required to release the retainer; the releasing element is driven to move in the second direction by the retainer.

It will be recognised that the retainer avoids the requirement for (and effectively 10 replaces) a detent mechanism for the locking element. The locking element is spring biased to its locking position and is retained in its unlocking position by the retainer.

Preferably the drive bar is a first drive bar and a second drive bar is also located in 15 the housing. Desirably the first and second drive bars are oppositely movable.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention will now be described in more detail, by way of example, with reference to the accompanying drawings, in which: Fig.1 shows a lock mechanism according to the present invention and which shares many features with a conventional lock mechanism as described above; Fig.2 shows a perspective view of part of the lock mechanism according to the invention in the secured and locked condition; Fig.3 shows a view as Fig.2, but in the secured and unlocked condition; Fig.4 shows an enlarged view of part of the lock mechanism of Fig.3; Fig.5 shows a view as Fig.3, during movement to the unsecured condition; Fig.6 shows a view of part of the lock mechanism in the unsecured condition; Fig.7 shows a first view as Fig.6, in the (re-)locked condition; and Fig.8 shows a second view as Fig.6, in the (re-)locked condition.

DETAILED DESCRIPTION

An almost complete description of Fig. 1 is provided above and will not be repeated. Whilst Fig.1 shows a lock mechanism which shares the features of the present invention, the relevant details are better seen in Figs. 2-8 and described below.

Some of the componentry of the lock mechanism of Fig.1 is omitted from Figs. 2-8 as it is not relevant to the present invention and its removal allows a clearer view of the relevant componentry.

Notwithstanding that the lock mechanism 10 has a latch 36 and a hook bolt 40, it will be understood that the present invention could be incorporated into lock mechanisms without those elements, or with a mortice bolt instead of a hook bolt, or with multiple bolts, as desired. Also, whilst the drawings show a lock mechanism having two oppositely movable drive bars, the invention could be used in a lock mechanism with a single drive bar. Thus, the present invention relates primarily to the operation of the locking element or vee-block 60, and in particular the movement of the locking projection 56 of the \me-block 60 into and out of the recess 58 in the drive bar 24.

Fig.2 shows the lock mechanism in the locked and secured condition, i.e. with the 30 hook bolt 40 extended and with the locking projection 56 of the vee-block 60 located in the recess 58 (Fig.3) of the first drive bar 24. As explained above, with the veeblock 60 holding the first drive bar in its locking position, the second drive bar 32 is also held in its locking position (as are any locking bars/shoot bolts connected to the respective drive bars).

It will be understood that Fig.2 represents the situation in which the key has not been rotated (nor perhaps inserted) in the Euro-cylinder lock located in the opening 66. The tumbler 62 is therefore in its rest position, out of engagement with the veeblock 60. It is typically arranged that the key can only be removed from the Eurocylinder lock when the tumbler 62 is in the position of Fig.2.

Upon insertion and rotation of the key, the tumbler 62 is rotated anti-clockwise as viewed, to the position of Fig.3. During this movement, the tumbler 62 engages the edge 64 of the vee-block 60 and moves the vee-block to the left. The vee-block is biased to the right by a spring 76; the spring 76 is compressed as the vee-block is driven to the left by rotation of the tumbler 62.

A retainer 80 engages the vee-block 60, the retainer being mounted to pivot upon a fixed beam 82 (Fig.4) of the housing 12. In particular, the retainer 80 can pivot between a releasing position shown in Fig.2 and a retaining position shown in Fig.3. The retainer is biased to its retaining position by a spring 84.

Accordingly, as the vee-block 60 is driven to the left by the tumbler 62 from the position of Fig.2, the retainer nose 86 slides along the top of a retainer tab 88 of the vee-block 60. When the end of the retainer tab 88 passes the end of the retainer nose 86 the spring 84 urges the retainer 80 to pivot to its retaining position as shown in Figs.3 and 4.

During this movement of the vee-block 60, the locking projection 56 moves out of the recess 58 of the second drive bar 24 and the lock mechanism 10 becomes unlocked. The operating handle can therefore be rotated to rotate the drive socket 14 anti-clockwise as represented by the arrow in Fig.5, which rotation causes the first drive bar 24 to move upwardly as drawn, causing corresponding downwards movement of the second drive bar 32, and withdrawal of the hook bolt 40.

Importantly, the anti-clockwise rotation of the operating handle and drive socket 14 also causes downwards movement of the rack 70 and biasing bar 72. A releasing element 90 is guided for sliding movement (upwardly and downwardly) relative to the housing 12. It is arranged that the (bottom) end of the biasing bar 72 can abut the (top) end of the releasing element as seen in Figs.5 and 6, whereby downwards movement of the rack 70 and biasing bar 72 causes downwards movement of the releasing element 90.

The bottom end of the releasing element 90 engages the outer end of the retainer 10 80 as shown in Figs.5 and Sand presses the outer end of the retainer downwardly, i.e. towards the fixed beam 82. Downwards movement of the outer end of the retainer 80 causes corresponding upwards movement of the retainer nose 86.

It is arranged that each time the operating handle is used to move the lock mechanism from its secured position to its unsecured position, the drive socket 14 rotates sufficiently (anticlockwise as drawn in Fig.1), and the biasing bar 72 and releasing element 90 move sufficiently (downwards as viewed in Fig.1) to release the retainer nose 86 from the edge of the retainer tab 88, permitting the spring 76 to push the vee-block 60 to the right.

Whilst the lock mechanism 10 is in its unsecured condition as shown in Fig.6 the vee-block 60 cannot move fully to the right because the recess 58 is out of alignment with the locking projection 56, and so the locking projection is pressed against the edge of the first drive bar 24 by the spring 76.

When the lock mechanism has been moved to its unsecured condition and the operating handle is released by the user it returns to its neutral (horizontal) position by way of the biasing bar 72 in known fashion. The biasing bar 72 causes the drive socket 14 to rotate clockwise from the position shown in Fig.6; the lost motion between the drive member 44 and drive cam 20 allowing that movement without corresponding movement of the drive cam. This return movement also causes the biasing bar 72 to move upwardly as drawn, out of engagement with the top end of the releasing element 90.

The lock mechanism 10 can remain in the unsecured position for as long as is required, with the door being held closed by the latch 36, and with the latch being actuated by way of anti-clockwise rotation of the operating handle and drive socket 5 14 in normal fashion.

The lock mechanism 10 can be returned to its secured position by clockwise rotation of the operating handle and drive socket 14. This rotation causes downwards movement of the first drive bar 24, causing corresponding upwards movement of the second drive bar 32 and extension of the hook bolt 40 as described above. When the recess 58 moves into alignment with the lock projection 56 the vee-block 60 is driven further to the right as drawn in Fig.1 by the spring 76, automatically re-locking the lock mechanism as is shown in Fig.7.

When the operating handle is subsequently released it again automatically returns to its neutral position by virtue of the biasing bar 72 and rack 70, in known fashion. Fig.8 shows the drive socket 14 it is return position (corresponding to a horizontal operating handle), the rotation of the drive socket (and operating handle) being permitted by the lost motion between the drive member 44 and the drive cam 20.

Claims

CLAIMS1. A lock mechanism having: a housing; a drive socket configured for connection to an operating handle; a drive bar in the housing, the drive socket being connected to the drive bar whereby rotation of the drive socket can be converted into linear movement of the drive bar; the housing having an opening to accommodate a key-operated lock; a locking unit within the housing, the locking unit including: a locking element which is located adjacent to the opening, the locking element being movable between a locking position and an unlocking position, the locking element in the locking position engaging the drive bar to limit movement of the drive bar, the locking element being resiliently biased to its locking position; a retainer which is movable between a retaining position and a releasing position, the retainer in its retaining position being able to hold the locking element in its unlocking position, the retainer being resiliently-biased to its retaining position, the retainer being engageable with a releasing element and being movable from its retaining position to its releasing position by way of the releasing element.
2. The lock mechanism according to claim 1 in which the drive bar has a recess and in the locking position a part of the locking element is located in the recess.
3. The lock mechanism according to claim 1 or claim 2 in which the direction of movement of the locking element is substantially perpendicular to the direction of movement of the drive bar.
4. The lock mechanism according to claim 3 in which the recess has opposing side edges and the side edges of the recess are both substantially parallel with the direction of movement of the drive bar.
5. The lock mechanism according any one of claims 1-4 in which the retainer is configured to pivot between its retaining and releasing positions.
6. The lock mechanism according to claim 5 in which the retainer pivot upon a fixed component in the housing.
7. The lock mechanism according to claim 6 in which the fixed component is a pivot beam.
8. The lock mechanism according to claim 7 in which the pivot beam is located between a part of the retainer and a part of the locking element.
9. The lock mechanism according to claim 8 in which the part of the locking element slides engages the pivot beam as the pivot beam also acts to guide the locking element at is moves between its locking and unlocking positions.
10. The lock mechanism according to any one of claims 1-9 in which the retainer has a retainer latch, in which the locking element has a retainer tab, the retainer tab having a side edge, and in which the retainer latch engages the side edge of the retainer tab in the retaining position.
11. The lock mechanism according to claim 10 in which the retainer tab also has a top edge, and in which the retainer latch engages the top edge of the retainer tab in the releasing position.
12. The lock mechanism according to any one of claims 1-11 in which the releasing element is slidably mounted in the housing.
13. The lock mechanism according to any one of claims 1-12 in which the releasing element is driven to move by way of rotation of the drive socket.
14. The lock mechanism according to any one of claims 1-13 in which the lock mechanism has a biasing bar engageable by the drive socket, and in which the releasing element is engageable by the biasing bar.
15. The lock mechanism according to claim 14 in which a part of the releasing element is aligned with a part of the biasing bar.
16. The lock mechanism according to claim 14 or claim 15 in which the releasing element is separable from the biasing bar.
17. The lock mechanism according to any one of claims 1-17 in which the drive bar is a first drive bar and in which the lock mechanism has a second drive bar in the housing.
18. The lock mechanism according to claim 17 in which the first and second drive bars are interconnected to move in opposing directions.
19. A method of operation of a lock mechanism according to any one of claims 118, the method of operation including the steps: {i} insertion and rotation of a key in the key-operated lock moves the locking element from its locking position to its unlocking position and permits movement of the (first) drive bar; {ii} as the locking element moves to its unlocking position the retainer is moved to its retaining position by way of a first resilient biasing means to hold the locking element in its unlocking position; {iii} rotation of the drive socket in a first direction moves the drive bar from a secured position to an unsecured position; {iv} rotation of the drive socket in step {iii} also moves the releasing element, the releasing element moving the retainer to its releasing position and allowing the locking element to move away from its unlocking position by way of a second resilient bias; {v} rotation of the drive socket in a second direction opposed to the first direction moves the drive bar from its unsecured position to its secured position; {vi} when the drive bar moves to its secured position the locking element moves to its locking position by way of a second resilient bias.
20. The method of operation according to claim 19 in which the releasing element is moved in step {iv} by a biasing bar which also acts to return the drive socket to a predetermined rotational position.