GB2584533A

GB2584533A - Lock mechanism

Info

Publication number: GB2584533A
Application number: GB2003343.7A
Authority: GB
Inventors: Matthew Corbett Brian
Original assignee: Spire Manufacturing Ltd
Current assignee: Spire Manufacturing Ltd
Priority date: 2019-03-07
Filing date: 2020-03-06
Publication date: 2020-12-09
Anticipated expiration: 2040-03-06
Also published as: GB2584533B; GB201903075D0; GB202003343D0

Abstract

A lock mechanism comprises a linear drive bar movable between two positions by a handle; movement of the drive bar prevented by actuation of a cylinder lock; the lug of the cylinder acting on a locking unit. The locking unit includes a linear locking element 62 engagable with the drive bar to retain the bar in position; a guide element (retainer) to guide linear movement of the locking element; and a detent mechanism 66 to retain the locking element in position. Guide formations such as guide rail 72, channel 74, are provide on the locking element 62 and retainer 64. The detent mechanism may be a spring biased ball bearing 82 engaging within recesses 80 in the locking element which may retain the locking element in the locked and unlocked positions. The guide element 64 may be fixedly housed within the housing by pegs 90 and prevents tampering of the locking element by manipulation tools.

Description

LOCK MECHANISM

FIELD OF THE INVENTION

The invention relates to a lock mechanism.

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

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 window panel and frame is typically sealed by resilient seals fitted to the window panel 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 point locking) or at more than one position (multi-point locking). Many known lock 25 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 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 and 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 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 to engage the locking bolts with 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 to engage the locking bolts with their respective keepers and the key-operated lock has been actuated.

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 Euro-cylinder lock. The installer can therefore choose to fit a particular Eurocylinder 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 latch, and some also include a mortice bolt or a hook bolt. In many of the known espagnolette lock mechanisms the mortice bolt or is 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 which is accessible from both sides of the door. The lock mechanism can therefore be locked and unlocked from both sides of the door, and the operating handle at each side of the door can 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 25 in Fig.1. Notwithstanding that this lock mechanism is according to the present invention it shares many features with the known espagnolette lock mechanisms and those shared features will be described below.

The lock mechanism 10 firstly includes several standard features, including a housing 12 with a depth D and a thickness T which are designed to fit into the Euro-groove of a door profile. In known fashion, the length of the housing 12 is not standardised as 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 is represented as transparent in Fig.1 so that some of the componentry of the lock mechanism 10 is made visible. The lock mechanism has a first 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 peg connected to an operating handle (not shown). A follower 16 is connected to the first drive socket 14 and rotates with the first drive socket. At least a part of the periphery of the follower 16 has projecting gear teeth which are engageable with the gear teeth of a rack 18 of a first drive bar 20.

The first drive bar 20 is mounted to slide linearly in the housing (substantially to the left and right as drawn in Fig.1) and has an extension part 22 carrying a primary rack. The primary rack is engageable by a secondary pinion 24, which pinion also engages a secondary rack of the second drive bar 30. The second is drive bar 30 is also mounted to slide linearly in the housing (substantially to the left and right 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 20 in a first direction, which linear movement is (by way of the pinion 24) converted into linear movement of the second drive bar 30 in a second (opposing) direction.

As seen, the first drive bar 20 an the second drive bar 30 extend along a large proportion of the housing 12, with suitable shaping and openings to pass other componentry in known fashion.

When installed into a door, the first and second drive bars 20, 30 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 lock mechanism 10 has connectors 28 which are provided for connection to the respective locking bars and/or shoot bolts.

In this example, the lock mechanism 10 also includes a spring-biased latch 32 and a hook bolt 34. The hook bolt 34 is pivotably mounted in the housing 12 and is also connected to the second drive bar 30. Accordingly, linear movement of the second drive bar 30 causes pivoting movement of the hook bolt 34, specifically between the extended (secured) position as shown and a retracted (unsecured) position in which more (and perhaps all) of the hook bolt is located inside the housing 12. The hook bolt 34 is therefore driven between its secured and unsecured positions by rotation of the operating handle in the first drive socket 14.

The latch 32 is, however, controlled separately, and in particular by a second operating handle (typically a thumb-turn) connected to the second drive socket 36.

to The thumb turn is typically mounted to the inside of the door (only) so that the latch 32 can readily be retracted by rotating the thumb-turn when it is desired to open the door.

To lock the door in the secured condition the housing includes an opening 38 to accommodate a key-operated Euro-cylinder lock (not shown in Fig.1 but partially shown in Fig.2). The Euro-cylinder lock includes a tumbler 40 which can actuate locking componentry within the lock housing 12 as explained in relation to the prior art arrangement shown in more detail in Fig.2.

Firstly, it will be understood that the first and second drive bars 20, 30 (and consequently the locking bars and/or shoot bolts connected thereto) and the hook bolt 34 are all interconnected to move together, so that it is only necessary to prevent the movement of one part of that linked mechanism in order to prevent the movement of all parts of the mechanism. The manufacturer of the lock mechanism shown in Fig.2 has taken advantage of the linked mechanism by providing locking componentry to prevent the movement of the second drive bar 30.

Specifically, the second drive bar 30 has a cut-out 42 which can accommodate the step 44 of a vee-block 46. The vee block is shown in Fig.2 in its unlocked condition, i.e. no part of the vee-block lies within the cut-out 42 and the drive bar 30 is free to move (leftwards as viewed) to its unsecured position. The vee-block 46 is, however, movable (upwardly as drawn) so that the step 44 enters the cut-out 42 so as to prevent movement of the drive bar 30 and thereby lock the second drive bar 30 in its secured condition.

The vee-block 46 is driven to move between its locking and unlocking positions by 5 rotation of the tumbler 40 of the Euro-cylinder lock, it being understood that as the tumbler 40 rotates clockwise from the position shown it will engage the edge 48 and move the vee-block 46 upwardly as drawn to its locking position.

To increase the security of the lock mechanism 10, the vee-block 46 is fitted with io a detent mechanism, specifically to hold the vee-block 46 in one or other of its locking and its unlocking positions. The detent is provided by a vee-block retainer 50 (which slides leftwards and rightwards as drawn) and which has a projecting peg 52 which can locate in one or other of the recesses 54 of the vee-block 46. The vee-block retainer 50 is biased to the right as drawn by a spring 56, and projects through an opening in the vee-block to be engaged by the tumbler 40 as shown.

It is a feature of Euro-cylinder locks that the key can only be inserted and removed when the tumbler 40 is in a particular rotational position, i.e. the key must be rotated through 360° in one direction to lock the mechanism and through 360° in the opposite direction to unlock the mechanism. In the key-removal position (not shown) the tumbler 40 is rotated away from the vee-block 46 and the spring 56 presses the vee-block retainer 50 to the right to engage the detent mechanism in one or other of the recesses 54.

It will be seen that the tumbler 40 can engage the vee-block retainer 50 and can move the detent mechanism to its released position as seen in Fig.2. Accordingly, rotation of the key-operated lock in the appropriate direction will act both to release the detent mechanism and to move the vee-block 46 between its locking and unlocking positions (Fig.2 showing the unlocking position).

The lock mechanism 10 includes componentry by which rotation of the tumbler 40 also moves the latch 32 to its retracted position so that the latch can be released from outside the door by way of the appropriate key.

It will be understood that even slight misalignment of the vee-block 46 could prevent the step 44 from entering into the cut-out 42, thereby preventing the locking of the mechanism 10. To help to ensure that the vee-block 46 maintains the required alignment a guide slot is typically formed through the top and bottom walls of the housing 12 and the vee-block 46 has a projecting guide rail (not to shown) which is located in and can slide along each of the guide slots. The guide slots and guide rails together ensure that the vee-block 46 is limited to linear sliding movement (upwards and downwards as drawn), directly into and out of the cut-out 42.

is The inventors have realised that the guide slots in the top and bottom housing walls presents a security weakness for the lock mechanism 10 which can be exploited by a person intent on releasing a locked door. In particular, many doors to which the lock mechanism 10 might be fitted are of plastics profile and an intending intruder can cut or break away the plastic wall or walls covering the housing 12. If the part of the housing 12 with the guide slot can be exposed, the intending intruder can access the guide rail and can push the guide rail to move the vee-block 46 to its unlocking position. It will be understood that sufficient force must be applied to the guide rail to overcome the detent mechanism, i.e. to force the peg 52 to slide up and over the triangular peak between the two recesses 54, but sufficient force to compress the spring 56 and move the vee-block 46 can often be applied. Because the tumbler 40 is spaced away from the vee-block 46 when the lock mechanism is locked it does not act to prevent such forced movement of the vee-block 46.

SUMMARY OF THE INVENTION

The inventors have sought to provide a lock mechanism which shares many of the features of the known lock mechanism described above and which includes all of 5 the practical benefits of that lock mechanism but which is less vulnerable to the threat set out above.

According to the invention therefore, there is provided a lock mechanism having: a housing; to a drive socket including a first opening through the housing and configured for connection to an operating handle; a drive bar within the housing, the drive socket being connected to the drive bar whereby rotation of the drive socket is converted into linear movement of the drive bar; is a second opening through the housing to accommodate a key-operated Eurocylinder lock; a locking unit within the housing, the locking unit including: a locking element which is located adjacent to the second opening, the locking element being configured for engagement by a tumbler of the key-operated Euro-cylinder lock when installed, the locking element being guided to slide along a substantially linear path 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; a detent mechanism to retain the locking element in its locking or in its unlocking position; a locking element retainer in engagement with the locking element; the locking element and the locking element retainer having cooperating slide formations to guide the locking element to slide linearly between its locking and its unlocking positions.

The locking element is somewhat similar to the vee-block of the prior art arrangement of Fig.2 and the locking element retainer is somewhat similar to the vee-block retainer of the prior art arrangement. In the present invention, however, the sliding movement of the locking element between its locking and its unlocking positions is guided by the locking element retainer rather than by guide slots in the housing wall. Preferably the locking element retainer is the only component guiding the sliding movement of the locking element. The requirement for the guide slots in the housing wall is therefore avoided and the identified security weakness caused by those guide slots is also avoided. In particular, an intending intruder who is able to expose the housing wall will not also expose a guide channel for the locking element and cannot access or move the locking element through a slot in the housing wall.

Preferably, the cooperating slide formations comprise a guide rail and a guide channel, the guide rail engaging the guide channel and being slidable relative to the guide channel.

Preferably, the guide rail is a part of the locking element and the guide channel is part of the locking element retainer. The locking element can therefore be at least partially surrounded by the locking element retainer whereby to provide additional material between the locking element and the housing wall and provide additional protection for the locking element.

Desirably, at least part of the guide channel is provided in a part of the locking element retainer which lies between the locking element and a housing wall.

Preferably the detent mechanism comprises a detent member, a compression spring and a recess which can accommodate a part of the detent member. The detent member can be mounted to the locking element retainer and the recess can be formed in the locking element. Alternatively the detent member can be mounted to the locking element and the recess can be formed in a fixed part of the lock mechanism, and ideally a fixed part of the locking unit. Desirably, the detent member is a ball bearing.

Desirably the detent mechanism has two recesses. In such an arrangement the engagement of the detent member in one of the two recesses can define the locking position of the locking element and engagement of the detent member in the other recess can define the unlocking position of the locking element.

Preferably the detent mechanism is not engageable by the tumbler or any other part of the Euro-cylinder lock. Unlike the prior art arrangement of Fig.2, therefore, the detent mechanism is driven to move solely by movement of the locking element; it is therefore not necessary for the Euro-cylinder lock to engage and release the detent mechanism as in the prior art arrangement. Instead, to release and actuate the detent mechanism it is only necessary for the detent member to to move and there is no requirement for the locking element retainer to move relative to the housing of the lock mechanism. The locking element retainer can therefore be fixed in position relative to the housing, for example being permanently pinned to the housing walls. The detent mechanism can move relative to the fixed locking element retainer. A fixed locking element retainer can provide a fixed and is reliable guide to support the locking element during its sliding movement between the locking and unlocking positions. Accordingly, the locking element can be guided to slide linearly by the locking element retainer rather than by guide slots in the housing walls. A fixed locking element retainer can also provide additional protection to the locking element.

The lock mechanism according to the invention is therefore less vulnerable to the threat explained above, firstly because no guide slot is required in the housing wall which might become accessible to an intending intruder, and secondly because the locking element can in certain embodiments be at least partially surrounded by the locking element retainer and therefore additionally protected from access and attack.

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;

Fig.2 shows a part of a prior art lock mechanism;

Fig.3 shows an exploded view of a first embodiment of locking unit of a lock mechanism according to the invention; and Fig.4 shows an exploded view of a second embodiment of locking unit of a lock mechanism according to the invention.

DETAILED DESCRIPTION

An almost complete description of Figs. 1 and 2 is provided above and will not be 20 repeated. Whilst Fig.1 shows a lock mechanism according to the invention, the differences over the prior art arrangement are not easily visible in Fig.1 but are described below.

Notwithstanding that the lock mechanism 10 has a latch 32 and a hook bolt 34, 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, as desired. Thus, the present invention replaces the vee-block 46 and the veeblock retainer 50 (and the associated detent mechanism) which together act to lock the second drive bar 30, and can therefore be used with any compatible lock mechanism.

The lock mechanism according to the invention includes a locking unit. A first embodiment of locking unit 60 is shown in exploded view in Fig.3 and this is the locking unit which is used in the lock mechanism of Fig.1). The locking unit comprises a locking element 62, a locking element retainer 64 and a detent mechanism 66.

The locking element 62 has a step 70 which is similarly sized and shaped to the step 44 of the vee-block 46 and can therefore locate into the cut-out 42 in the drive bar 30 in the locking position.

The locking element 62 has a guide rail 72 which locates in and can slide along a to guide channel 74 in the locking element retainer 64. Thus, from the position shown in Fig.3 the locking element can be moved downwardly to enter into the guide channel 74 of the locking element retainer 64. In use, the locking element 62 can slide (upwardly and downwardly as drawn) relative to the locking element retainer 64 between its locking and unlocking positions.

The locking element has a recess 78 to accommodate the tumbler 40 of the Eurocylinder lock; the recess is shaped identically to that of the prior art arrangement so that rotation of the tumbler in one direction engages one of the edges of the recess 78 and moves the locking element (upwardly as viewed) to its locking position in which the step 70 lies within the recess 42 of the second locking bar 30; rotation in the other direction engages the other edge of the recess 78 and moves the locking element (downwardly as viewed) to its unlocking position.

The locking element also has two recesses 80, each of which can accommodate 25 a part of a detent member 82 (in this embodiment a ball bearing). In the assembled locking unit 60 the ball bearing 82 is pressed through the tubular opening 76 into one or other of the recesses 80 by a compression spring 84.

The ball bearing 82 and the compression spring 84 are carried by the locking 30 element retainer 64. The end of the compression spring 84 opposing the ball bearing 82 is held stationary by a fixed lug 86 (see Fig.1) which lies between the arms 88 of the locking element retainer 64.

It will be understood that the detent member 82 can move relative to the locking element retainer 64 sufficiently to permit movement of the locking element 62 between its locking and unlocking positions (with the ball bearing 82 moving between the two recesses 80); there is no requirement for the locking element retainer 64 to move relative to the lock housing 12. Accordingly, the locking element retainer 64 is fixed in position, in this embodiment by two rigid pegs 90 which project into holes formed in the housing wall. The pegs 90 are visible in Fig.1.

A second embodiment of locking unit 160 is shown in Fig.4. The locking unit 160 comprises a locking element 162, a locking element retainer 164 and a detent mechanism 166.

The locking element 162 has a step 170 which is similarly sized and shaped to the 15 step 44 of the vee-block 46 of Fig.2 and can therefore locate into the cut-out 42 in the drive bar 30 in the locking position.

The locking element 162 has a guide rail 172 which locates in and can slide along a guide channel 174 in the locking element retainer 164. Thus, from the position shown in Fig.4 the locking element 162 can be moved upwardly to enter into the guide channel 174 of the locking element retainer. In use, the locking element 162 can slide (upwardly and downwardly as drawn) relative to the locking element retainer 164, between its locking and unlocking positions.

The locking element has a recess 178 to accommodate the tumbler 40 of the Euro-cylinder lock; the recess 178 is shaped identically to that of the prior art arrangement so that rotation of the tumbler in one direction engages one of the edges of the recess 178 and moves the locking element 162 (upwardly as viewed) to its locking position in which the step 170 lies within the recess 42 of the second locking bar 30; rotation in the other direction engages the other edge of the recess 178 and moves the locking element 162 (downwardly as viewed) to its unlocking position.

The detent mechanism 166 is configured slightly differently in the locking unit 160 than in the locking unit 60, but fulfils the same function. In this embodiment a detent element 176 has two recesses 180, each of which can accommodate a part of a detent member 182 (in this embodiment also a ball bearing). In the assembled locking unit 160 the ball bearing 182 is pressed into one or other of the recesses 180 by a compression spring 184.

The ball bearing 182 and the compression spring 184 are mounted inside a tubular housing 186 of the locking element 162 (a part of the ball bearing 182 to projecting from the end of the tubular housing 186 in the assembled condition). The tubular housing 186 lies alongside a wall 188 of the detent element 176.

It will be understood that the tubular housing 186 and the detent member 182 can move relative to the detent element 176 sufficiently for the ball bearing 182 to move between the two recesses 180 to define the locking and unlocking positions of the locking element 162. There is no requirement for the detent element 176 or locking element retainer 164 to move relative to the lock housing to which it is fitted. Accordingly, the locking element retainer 164 and the detent element 176 are both fixed in position in the housing. The locking element retainer 164 is fixed similarly to the embodiment of Figs. 1 and 3, i.e. by two rigid pegs 190 which project into holes formed in the housing wall. The detent element 176 is fixed by way of a rigid peg passing through an aperture 192.

It will be understood and an intending intruder who cuts or breaks away the material of the door to gain access to the housing 12 has no exposed guide slot by which to attack the lock mechanism, but instead faces a rigidly mounted locking element retainer. The locking element 62/162 is protected both by the continuous housing wall, but also by the material of the locking element retainer 64/164 which partially surrounds the locking element 62/162 and has a part which lies between the housing wall and the locking element. The likelihood of the lock housing 10 being successfully attacked in the manner similar to that described above in relation to the prior art structures is therefore largely or completely eliminated.

Claims

CLAIMS1. A lock mechanism having: a housing; a drive socket including a first opening through the housing and configured for connection to an operating handle; a drive bar within the housing, the drive socket being connected to the drive bar whereby rotation of the drive socket is converted into linear movement of the drive bar; to a second opening through the housing 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 second opening, the locking element being configured for engagement by a part of the key-operated Euro-cylinder lock when installed, the locking element being guided to slide along a substantially linear path 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; a detent mechanism to retain the locking element in its locking position; a locking element retainer in engagement with the locking element; the locking element and the locking element retainer having cooperating slide formations to guide the locking element to slide linearly between its locking and its unlocking positions.
2. The lock mechanism according to claim 1 in which the cooperating slide formations comprise a guide rail and a guide channel.
3. The lock mechanism according to claim 2 in which the guide rail is a part of the locking element and the guide channel is part of the locking element retainer.
4. The lock mechanism according to claim 3 in which the locking element is at least partially surrounded by the locking element retainer.
5. The lock mechanism according to any one of claims 1-4 in which at least part of the locking element retainer lies between the locking element and walls of the housing.
6. The lock mechanism according to any one of claims 1-5 in which the locking element retainer is fixed in position relative to the housing.
7. The lock mechanism according to any one of claims 1-5 in which a part of to the detent mechanism moves relative to the locking element retainer.
8. The lock mechanism according to any one of claims 1-7 in which the detent mechanism comprises a detent member, a compression spring and a recess which can accommodate a part of the detent member.
9. The lock mechanism according to claim 8 in which the detent member is mounted to the locking element retainer.
10. The lock mechanism according to claim 9 in which and the recess is formed in the locking element.
11. The lock mechanism according to claim 8 in which the detent member is mounted to the locking element.
12. The lock mechanism according to claim 11 in which the recess is formed in a fixed part of the lock mechanism.
13. The lock mechanism according to claim 12 in which the recess is formed in a fixed part of the locking unit.
14. The lock mechanism according to any one of claims 8-13 in which the detent member is a ball bearing. is
15. The lock mechanism according to any one of claims 1-14 in which the detent mechanism is adapted to retain the locking element in its locking position and in its unlocking position.
16. The lock mechanism according to claim 15 in which the detent mechanism has two recesses.
17. The lock mechanism according to any one of claims 1-16 in which the detent mechanism is not engageable by any part of the Euro-cylinder lock in use.