GB2584112A

GB2584112A - Locking mechanism

Info

Publication number: GB2584112A
Application number: GB1907176.0A
Authority: GB
Inventors: Rowlands Peter; Hutton Melvin; Lynch Aidan
Original assignee: VBH GB Ltd
Current assignee: VBH GB Ltd
Priority date: 2019-05-21
Filing date: 2019-05-21
Publication date: 2020-11-25
Also published as: GB201907176D0

Abstract

A locking mechanism a window, with a lock assembly attached to the window sash and comprising a trigger with a free end triggering point, at least one sprung latching member 122 which moves to an extended locking position, the trigger being able to pivot between a free end retracted and free end extended position and slide between an inner and outer position, the locking mechanism also having a keep section 101, preferably for a corner, which is mounted to the window frame and has a moveable catch 110 such that in use when the window is closed, the trigger engages with the catch member, triggers (preferably rotates) and releases the sprung latching member to extend into the keep. When the window is unlocked, the lock connectors (112 Fig 2b) preferably move the trigger to the inner position such that it interacts with the moveable catch to move it from a catching position to a reset position (Fig 6a-e) within the striker. The locking mechanism allows the window to be placed in an initial latched position when it is closed even if the central latch (105 Fig 1) has not actuated.

Description

Locking Mechanism The present invention relates to a locking mechanism for casement windows. BACKGROUND Automatic latching mechanisms for doors are known in the art. For example, doors are commonly fitted with central latches that can latch the door shut simply by being pushed shut by a user -they do not require further intervention by a user to latch them shut. Further intervention may be needed to lock the latches, or to deadlock them, but the doors themselves latch into the closed position when closed. Conventional casement windows, on the other hand, generally are either manually latched shut or are left free to swing between open and closed positions. Some even allow locking in open as well as closed positions, depending upon the operational state of the window handle and the connected window latch mechanism, as operated on by an internal gear mechanism that connects the latch mechanism to the handle. Casement windows thus require a further action to be taken by the user in order to latch or secure the window in a closed position upon shutting it -usually turning the handle or a key in order to latch closed the window in its window frame. It would be advantageous, however, to provide a casement window that provides an improved level of security such that upon it being pushed closed, it will latch. The present invention thus seeks to provide a mechanism for casement windows so that they can have this capability.

STATEMENT OF INVENTION

For the purpose of this disclosure, a window is the element that swings open and closed, whereas the frame defines the opening into which the window fits, and from which the window is hung. However, some windows are directly hung to the wall, absent a frame, although for uPVC and aluminium windows the frame is usually essential.

The frame (or element to which the window is hung) and the window together are referred to as a window assembly.

The invention can be used with wood and steel windows, as well as plastic (usually uPVC), glass fibre and aluminium windows.

In accordance with one aspect of the present invention there is provided a locking mechanism for selectively securing a window in a closed position, the locking mechanism comprising a lock assembly configured to be attachable to said window, and a keep section for the lock assembly to latch within, wherein: the lock assembly has at least one sprung latching member and the keep section comprises at least one receiver for selectively accommodating the sprung latching member to latch the lock assembly within the keep section to secure the window in the closed position; the keep section further comprises a moveable catch; and the lock assembly further comprises: a trigger comprising a free end, the trigger configured to: a) pivot between a free-end-retracted condition and a free-end-extended condition, the pivoting defining a first range of motion; and b) slide between an inner position and an outer position, the sliding defining by a second range of motion; and the trigger being configured to selectively engage the moveable catch to trigger the sprung latching member to fire it into a latching state, and to subsequently interact with the movable catch to move the moveable catch from a catching position to a reset position.

In an embodiment of the invention a side of the free end bears against a side of the moveable catch when the window is being closed such that said trigger engages the moveable catch to trigger the spring latching member.

In an embodiment of the invention the trigger slides from the inner position to the outer position upon operation of a handle of the locking mechanism in a first direction.

In an embodiment of the invention the trigger slides from the outer position to the inner position upon operation of a handle of the locking mechanism in a second direction.

In an embodiment of the invention the trigger is adapted to interacts with the moveable catch to move it from said catching position to said reset position as the trigger slides back from the outer position to the inner position while the window is closed.

In an embodiment of the invention the free end of the trigger interacts with an end of the moveable catch when moving it from said catching position to said reset position during the unlatching process.

In an embodiment of the invention the movable catch moves under a housing of the keep section when it moves to the reset position.

In an embodiment of the invention said sprung latching member is attached to a second, retracted part of the trigger when the trigger is in said free-end-extended condition, and it fires by the second part pivoting away from the latching member as the trigger moves towards its free-end-retracted condition extending.

In an embodiment of the invention the sprung latching member comprises a linearly sliding shootbolt with a spring bias adapted to drive the latching member towards an extended position.

In an embodiment of the invention the shootbolt has a free end that engages into a receiver of the keep section upon it firing, the engagement comprising an extension of the shootbolt's free end from the edge of the window into the receiver.

In an embodiment of the invention the receiver is a through hole in the keep section.

In an embodiment of the invention the sprung latching member further comprises a guide block configured to fit into a guide channel of the keep section. Preferably the guide channel is a slot with a tapered mouth to facilitate initial insertion of the guide block therein when advancing with the shootbolt.

In an embodiment of the invention the keep section comprises a corner keep, the receiver being in the corner keep, and the sprung latching member being arranged to fire such that it then engages the receiver in that corner keep.

In an embodiment of the invention the locking mechanism comprises a second corner keep like the first and a second lock assembly therefor, the second lock assembly being like the first in having a sprung latching member and trigger.

In an embodiment of the invention the locking mechanism further comprises a central gearbox for mounting in the window, the gearbox operable by a handle or key, the gearbox being for driving movement of the trigger along the second range of motion via one or more interconnecting link member.

In an embodiment of the invention the central gearbox comprises a central latching member for selectively extending into a centre keep.

The present invention also provides a window fitted with a locking mechanism as defined above or below with reference to the accompanying drawings.

The keep section can be configured to be installed into or onto a frame in a wall, or an outer frame of a window assembly. The lock assembly can be configured to be installed into the outer edge of a casement window. The keep section may be installed into or pre-assembled in the frame (or a frameless wall cavity).

The keep section may be part of a keep assembly, which keep assembly may be formed as one unit -all components thereof being joined together and fitted as one to the frame, but preferably instead the keep section has multiple -perhaps three separate, preferably different arranged, keeps, such as a centre keep positioned between two corner keeps.

The corner keeps may mirror one another. The centre keep may be for a central latching part of the locking mechanism, but it is non-essential to the invention, which primarily concerns a corner keep and lock assembly therefor.

There can be additional or fewer keeps -typically a number to match or accommodate the number of multi-point securement areas of the locking mechanism -such that there is usually one keep section for each lock assembly, which lock assemblies are joined together to form a multipoint lock unit.

For additional security, the keep assembly may have multiple central keeps between the corner keeps, each spaced suitably between the corner keeps to face one or more of the multi-point securement elements of the locking mechanism.

The keeps are configured to house or receive a protruding element from the lock assembly to latch the window in a closed position when activated by a handle of the locking mechanism.

In an embodiment of the present invention, the keep section is a corner keep that preferably wraps around a corner of the frame. The corner keep is provided in the corner to receive a corresponding corner of the window when the window is closed.

The lock assembly is then a corner lock assembly fitted to the window corner.

The keep section is configured to receive a latching element from the lock assembly, which latching element may be referred to as one or more of a shoot, a bolt, a shootbolt, an arm or a protruding member. For the purpose of this disclosure these will be generically referred to as a shootbolt, which activates linearly, rather than by rotating as a hook.

The keep section receives the shootbolt through or in a first receiver, the first receiver preferably being a hole in the keep section shaped to receive the shootbolt when the shootbolt linearly extends out of an edge of the window.

For example, the first receiver may be a hole in the keep section that extends depthwise in the direction of linear travel of the extending shootbolt. The hole in the keep section may be a through-hole, extending fully through the keep section or it may be a blind hole, extending only partially through a body of the keep section, like a well or an indent, or recess.

When provided, the centre keep is configured to receive one or more mid-lock element configured to project from the central lock assembly (i.e. the gearbox unit).

The centre keep receives the mid-lock element at a centre keep receiver. The centre keep receiver is configured to receive the mid-lock element, which can be conventional in design. For example, it might be engaged in the receiver via a rotational movement as well as, or in place of, a linear movement. Therefore, the centre keep receiver may be physically different to the corner keep receiver in terms of how it interacts with the mid-lock element(s). For example, the centre keep receiver may be configured to receive a mid-lock element that takes the form of a rotating hook or latching bar.

The corner keep(s) and the centre keep(s) may be configured to be connected to one another via a connector such as a connecting beam or rod. Alternatively, each keep section may be separately installed and secured into, for example, the frame for the window. However, advantageously, if the keep sections are connected to one another, installation may be more accurate because the spacing between the keeps can then be preconfigured to match the spacing of the multi-point lock unit.

That preconfiguration can even be with adjustability -whereby both can be adjusted to a preconfiguration length suitable for the given window size, or the given frame size, so as to correctly fit to the given window and frame.

The keep section is preferably fitted with a housing that encases the component parts of the corner keep. The housing can be provided with fixing points so it can be used to securely fasten the keep section to a frame or wall, e.g. with screws.

The keep section comprises a moveable element that acts as a catch for a trigger of the lock assembly. The details and importance of the interaction between the moveable element and the trigger will be explained below. The moveable element may be referred to as one or more of a catch, a slideable arm and a triggering element. Physically, the catch may have chamfered sides. The chamfered sides advantageously interact with sides of the trigger (of the locking assembly), which may also be chamfered. This can enhance the smoothness of the triggering of the latch mechanism by allowing the trigger to be triggered by a lower force than if the catch (and/or trigger) did not have chamfered sides.

The catch has a biasing means that by default extends the catch to a triggering position. The biasing means is herein referred to as a catch biasing device. The catch biasing device may be a spring -e.g. a compressible coil spring mounted, for example, in a housing for the catch. However, numerous other biasing means, including elastic and magnetic arrangements, might instead be used.

The catch may extend out from a catch housing of the keep section when in the default position. The catch housing may accommodate most of the catch, and the catch biasing device when the catch is instead moved into a retracted (or trigger reset) position. However, when there is no force applied against the catch towards that retracted position, the biasing means drives that catch at least partially out of the catch housing.

Different positions and arrangements of the catch and catch biasing means are possible but generally the catch has a first, default, position and a second, retracted, position. The first position of the catch is such that the catch will engage with a trigger of the locking assembly when the window is being closed. The first position of the catch may thus be referred to as a catching or triggering position as the catch will trigger the trigger upon that window closure. The second position of the catch is such that the catch will not trigger the trigger. The second position of the catch may be referred to as a housed or retracted position because when the catch is in the second position, the catch is retracted from that triggering position -usually such that it is at least partially housed in the catch housing.

When the catch is in the retracted, or housed position, the catch may be substantially completely housed in the catch housing.

Thus, depending on the position of the catch, the catch is configured to either be positioned to trigger the tiger or positioned not to trigger the trigger, it sliding between these positions during use of the latching and locking/unlocking processes for the window.

For a corner keep, the catch biasing device is configured to bias the catch towards a corner of the corner keep, extending the catch in a linear direction substantially fully out of the catch housing. The catch biasing device may be configured to move the catch between the first and second positions in a rotational movement (in addition to or alternatively to the linear movement), but in a preferred arrangement the movement is just linear.

The catch is configured to be moved from the first position to the second position due to contact with the trigger during the window unlocking process. The force applied by the contact between the trigger and the catch during that opening process is opposed by the catch biasing means, but the bias will be overcome as the spring bias force needs only to be enough to allow the catch to re-extend when released by the trigger.

The keep section (and frame) is further configured to comprise a recess in its side to allow the trigger and, where provided a guide block of the lock assembly, to side-load into the keep section as the window closes, and likewise to exit the keep section as the window is opened.

The lock assembly may comprise two corner units and a centre unit. Each of these units may comprise a number of internal components encased in a housing.

Each of the corner units will be connected to the centre unit by connectors, which may be made of one or more elongated elements. Such connectors provide a mechanical connection for transferring movements of the gearbox of the centre unit to the two corner units. The connectors may be a rod or a series of connected rods, such that they are mechanically joined together.

Each corner unit comprises a trigger for selective connection to a shootbolt. When the window is open, and the shootbolt retracted behind the edge of the window, the trigger links with the shootbolt to hold the shootbolt in its retracted state. When the trigger is triggered, which may also be referred to as released, the shootbolt is released which allows it to extend out of the edge of the window -away from the centre unit. The extended shootbolt may be referred to as being in an extended position. However, when the shootbolt is within the corner unit, rather than extended, the shootbolt may be referred to as being in a withdrawn position.

When the lock assembly is positioned to face the keep section -i.e. the window is closed, then the shootbolt will extend into the receiver of the corner keep.

The corner block comprises a shoot biasing device which causes the shootbolt to extend when the trigger is released from the shootbolt.

A trigger biasing device causes the trigger to be biased towards a shootbolt latching position, where the trigger becomes secured to the shootbolt. This position also happens to be when the outer end of the trigger is raised into a position in which it would be able to engage with the catch.

The trigger is mechanically connected with the centre unit or gearbox. The trigger thus can be moved by a turning of a handle (and/or a key) at the centre unit. For example, the trigger may be connected to a connecting arm that extends from the corner unit to the centre unit. The connecting arm may be in mechanical connection with cogs of the gearbox, whereby when the gearbox is driven by the turning of the handle (and/or key), the gears move the connecting arm, and thus the trigger. For this purpose the trigger is held in a trigger mount, which mount is connected to the connecting arm. The connecting arm may be a single arm or multiple separate arms joined together. The length of the arm is typically set for a given window, and may be adjustable for allowing it to fit multiple different windows.

The position of the trigger can be changed due to a force applied to, and consequent movement of, the connecting arm. The force may result in a longitudinal movement of the connecting arm parallel to the side of the window, which in turn moves the trigger in that longitudinal direction. The movement of the trigger may be referred to as a first range of movement. In other words, the movement of the trigger caused by the movement of the connecting arm (ultimately caused by the turning of gears at the centre unit) may be referred to as a sliding motion of the trigger. However, movement of the trigger is not limited to that sliding motion -during triggering by the catch it instead moves about a pivot. This pivoting movement is defined by two separate end conditions, either of which can occur during the sliding movement -sliding movement during locking occurs in one end condition, whereas sliding movement during unlocking and unlatching occurs in the other end condition.

A triggering (also referred to as a release) of the trigger equates to a motion of the trigger from the unlatching condition to a latching condition -in the latter of which the shootbolt is released by the trigger, allowing the shootbolt to be fired by its spring to an extended state. The trigger is triggered by a compression of a free end of it from an extended or raised state (where it extends laterally from the side of the window) to a lowered state where it has sunk relative to the side of the window. This occurs by its engagement against the catch as the window is closed.

When the trigger is moved to this lowered state, the other end of the trigger releases the shootbolt by a shoulder of it releasing out of a receiver or hole or well in the body of the shootbolt. This then lets the shootbolt fire.

Advantageously, the shootbolt also comprises a guide block. The guide block fits into a guiding channel positioned in the corner keep to correctly close and latch the window, with the guiding action of the guide block being provided by a tapered mouthed of the guiding channel (or slot) in the keep section, thereby aligning also the shootbolt with the first receiver. The shootbolt thus will enter the first receiver correctly whenever it fires upon the window being closed.

With the shootbolt positioned inside the first receiver of the corner keep, the window is secured in that shut state. This is advantageous over the prior art because the window now provides an increased level of security merely by it latching upon it being pushed closed, thereby alleviating the need to turn a handle or a key, in order to secure the window.

The user can provide further security by turning the handle or key and thus also the gearbox. This causes one or more hooks to extend from the centre block into the centre keep (if provided). Further, the resulting movement of the trigger allows it to reattach itself to the extended shootbolt. Additionally, the trigger is moved enough to move it beyond an end or tip of the catch. As the trigger is beyond the end of the catch, the catch no longer compresses (i.e. triggers) the trigger, whereby the trigger returns to the extended position due to trigger biasing device. Therefore, in response to the gearbox being driven, the hook in the central block (if provided) engages and the shootbolt and the trigger reattach to one another, thus allowing the shootbolt and guide block to be effectively jammed in their latching conditions. The locking assembly is therefore secured to the centre and corner keeps and is therefore more secure than from just the fired shootbolts.

The user can then unlock and open the window by turning the gears in the opposite direction to that which locked the window. In more detail, when the handle or key is turned in the opposite direction to that which locks the locking assembly, the connecting arm is retracted back into an original or window open position. As the gearbox is mechanically connected to the hook of the centre unit, the resulting movement of the gearbox also retracts the hook back into the centre unit. As the connecting arm is in mechanical contact with the trigger, the resulting movement thereof also retracts the trigger. As the trigger is attached to the shootbolt, the movement of the trigger then also moves the shootbolt back to its initial retracted position. Therefore, the locking assembly now has no latched elements at this point in the process.

Furthermore, the retraction of the trigger by the gearbox also causes a movement of the catch into its retracted position (e.g. into its housing) because the trigger, when positioned in the extended position, has its free end positioned at the end of the catch. Therefore, movement of the trigger from that extended position -both longitudinally and pivotally, into the longitudinally retracted position moves the catch longitudinally against the catch biasing device. This means that when the locking assembly is being unlatched, the catch does not trigger the trigger because the catch is instead pulled longitudinally by the path of the trigger.

Without the ability to move the catch out of the path of the trigger, the trigger would be triggered when the window (comprising the licking assembly) was opened, which would prevent the window from then being closable (as the shootbolts would fire.

The movement of the catch by the trigger is thus an important feature for the present invention.

BRIEF DESCRIPTION OF DRAWINGS

These and other features of the present invention will now be described, purely by way of example, with reference to the accompanying drawings in which: Figures la to 1d show a locking mechanism of the present invention in four conditions from an about to be closed condition, to a closed and latched condition to a latched and locked condition and finally to a released and ready to open condition, but not yet opened.

Figures 2a and 2b show two views of a corner keep interacting with a corner block of the locking mechanism of Figure 1 -in the condition of Figure lb. Figures 3a and 3b show the corner keep in a first condition -corresponding to that of Figure la, in which it has received or in which it is ready for receiving a closing casement window -in a complete view -3(a) and a cutaway view -3(b), each with a catch of the keep in a default position.

Figures 3c and 3d instead show the corner keep in a second condition -corresponding to that of Figure ld, and thus ready for opening of a closed casement window -in a complete view -3(c) and a cutaway view -3(d), with the catch thereof drawn into a displaced position against a spring bias.

Figures 4a to 4e show a locking mechanism in five conditions for showing the condition of a trigger during the steps of a) window closing, b) trigger actuating, c) latch firing, d) latch locking and e) trigger release, with a cover and trigger sidewall thereof removed in Figures 4d and 4e for clarity.

Figures 5a to be show further details of the locking mechanism, with 5a corresponding to 4a, 5b corresponding to 4b, albeit with the cover and trigger sidewall removed for clarity, 5c corresponding to 4c but with the cover and trigger sidewall removed for clarity, 5d corresponding to 4d, but with the trigger sidewall shown, Figure 5e corresponding to Figure 4e, but with the trigger sidewall shown.

Figures 6a to 6e show a locking mechanism in five conditions for showing the condition of a trigger during the steps of window opening, starting from a) with the window closed and locked with the cover shown, b) the window closed and locked with the cover removed but the trigger sidewall shown, c) with the trigger and shoot being retracted by the handle to start displacing the catch of the keep by engagement therewith by the trigger, with the cover and trigger sidewall removed, d) with the catch in the displace position and the cover shown, and finally e) where the window is opened releasing the catch so it springs back to its default position, ready to actuate the trigger when the window is once again closed..

Figure 7 shows a more detailed view of a corner section of an exemplary locking mechanism, in a longitudinal cut away view.

Figure 8 shows a similar cut away view of a whole three section locking mechanism.

Figure 9 shows a perspective view of the three section locking mechanism of figure 8.

Figure 10 shows a side elevational view of the locking mechanism of Figure 8.

Figure 11 shows a window incorporating the locking mechanism of the present invention.

DETAILED DESCRIPTION

Referring first to Figure 16, a general schematic illustration of a window with a locking mechanism 10 of the present invention is shown. The locking mechanism 10 comprises a keep section 12 and a lock assembly 14. The keep section 12 is installed into (or onto) a frame 18 in a wall 8. The lock assembly 14 is installed into the outer edge 24 of a casement window 20. The keep section 12 of this illustrative embodiment has three separate, differently arranged, keeps 101, 101a, 101b, namely a centre keep 101b positioned between two corner keeps 101, 101a. The corner keeps 101, 101a mirror one another, and are thus "handed", with a top one and a bottom one switching to bottom and top depending upon the direction of opening/closing of the window -i.e. left hand hinge or right hand hinge.

The centre keep 101b is for a central latching part of the locking mechanism.

Although there can be additional or fewer keeps (e.g. just the corner keeps, or one corner and one central keep, or more than three keeps, for the purpose of this disclosure we describe this three keep embodiment.

The keeps are configured to house or receive a protruding element from corresponding parts of the lock assembly 14 that act to lock the window in a closed position when activated by a handle 26 of the lock assembly 14 (once installed in the window 20 and attached thereon with a suitable centre-pin).

In the embodiment of the invention shown in the drawings, the locking mechanism 10 comprises an auto latching shootbolt kit that comprises two "handed" corner keeps 101, 101a -i.e. a top and bottom one that mirror each other, a centre keep 101b, two auto shootbolt end sections 103, 103a, and a centre gearbox 105. The keeps can be mounted together as a frame assembly for mounting together in or on the frame 18, but here they are separate components, as shown, for mounting each separately into a recess that may be cut or formed in the frame.

The corner keeps 101, 101a each have a moveable catch 110, as part of the auto fire trigger mechanism, built in to them. The shootbolt end sections 103, 103a each have a trigger 108 and at least one spring-biased shootbolt 122 built into them for actuation by interaction between the catch 110 and the trigger 108. Thus, as the casement window 20 swings on its hinges 28 in the frame 18 so as to enter into the opening 30 of the frame 18, the triggers 108 (or other such release levers) within the shootbolt end sections 103, 103a are both actuated -by being pressed by their engagement against the movable catches 110 into a depressed position (see Figure 1(b)). This releases the sprung loaded shootbolts 122 (herein there is one at the top and one at the bottom of the window 20), which then each protrude out from the top and bottom (near the corners of the casement window 20 to engage into holes 102 in the corner keeps 101, 101a.

As each shootbolt 122 moves along its path -herein a longitudinal, axial sliding motion, a sidewardly projecting guide block 106 (attached to the same body as the shootbolt) also locates into a receiver 104 therefor that is also built into the keep (see Figure 2b). The shootbolt 122 and guide block 106 thus will hold the window 20 closed, preventing the window 20 from being swung open again (until this latching condition is reversed).

The guide block 106 is a flanged pin in this embodiment and the receiver is a slot with a gap to accommodate the shaft of the pin and an open reverse side to accommodate the flange. The pin thus fits into the receiver or slot 104 from a side of the slot and offers a secure retention of the window once they are inter-engaged together, especially when combined with the shoot bolt which inter-engages or locates into its own hole 102 in the frame (or, as here, in the corner keep 101).

Further security engagements are introduced by operating a handle 26 (see Figure 1(c)). Operating the handle -rotating it anticlockwise (in Figure 1c) or upwards (in Figure 16, as would be conventional in the art for a window latching process, although it can be arranged differently), then additionally operates the gearbox 105 -example internals for which are shown in Figures lc and 1d in the lower version without a cover. That gearbox operation is to latch or lock a central latch (e.g. a laterally movable latch or a swinging hook, not shown) into the centre keep 101b, and it also drives link members 112, 112a to move elements in the shootbolt end sections to jam or lock the shootbolts in their latched state.

That further security engagement additionally moves a member onto a trigger assembly in the shootbolt end sections to allow a retraction or reset of the trigger 108 when the window is reopened -a process during which all projecting latching elements are withdrawn or lifted out of their receivers/holes as the handle is operated again here in the clockwise (Figure 1d) or down (Fig 16) direction (as is again conventional for opening a window).

Referring now specifically to Figure 1A there is shown a locking mechanism 100 in an open, retracted position. The locking mechanism compromises a corner keep 101, a second corner keep 101a, a centre keep 101b and a lock assembly 100a.

The corner keep 101 comprises a first receiver or hole 102 (not visible), a second receiver or slot 104 and a recess 120. The corner keep 101 further comprises a catch 110. The catch 110 is a moveable catch and optionally has a chamfered side. In the locking mechanism 100, the centre keep 101b is positioned between each of the corner keeps 101 and 101a. In use, the corner keeps 101 and 101a and the centre keep 101b are positioned in a window frame 18, for example in a wall 8 of a building.

The lock assembly 14, 100a instead comprises two corner blocks -the shootbolt end sections 103 and 103a and a centre block or gearbox 105. The corner blocks 103 and 103a comprise a trigger 108 and optionally each comprise a guide block 106. The centre block 105 comprises a central lock or latching mechanism 114. The central lock 114 comprises an opening 118 for a handle mechanism and operational gearing as known in the art for moving the link members 112 and any latch for engaging into or with the central keep.

The corner blocks 103 and 103a are connected to the centre block 105 via the link members or connectors 112 and 112a, which may comprise a face plate and a slider, although here the face plate is discontinuous -being three separate face plates -one for each block 103, 103a, 105.

In figure 1A, the lock assembly 14, 100a is in an open, latch-retracted condition. This corresponds to when the casement window comprising the lock assembly 100a is open. Figure 1A corresponds to a point in time just before the window (comprising the lock assembly 100a) is closed by the user. As can be seen, in Figure 1A, the trigger 108 extends behind, and is almost in contact with, the catch 110 of the corner keep. As they have not contacted against each other, the trigger 108 is not yet compressed by the catch 110.

The guide block 106, in this condition, is positioned to overlie or align with the recess 120, and as such the guide block passes into the recess as the window closes -transverse to the frame. The recess 120 is configured to accommodate the guide block 106 by being wider than it.

In figure 1A, the shootbolts of the lock assembly 100a do not project out of the left or right sides of corner blocks of the lock assembly 100a as they are retracted. This is to allow the window comprising the lock assembly 100a to move from an opened position into a closed position without impediment by those shoot bolts, which would stop the window closing. The guide blocks, however, avoid creating an impediment due to the recesses 120 (while the shootbolts 122 are retracted).

Referring next to Figure lb, the catches 110 of the corner keeps are configured to be engaged against by the triggers 108 to compress the triggers 108 when the window 20 is then pushed or pulled to a closed state -fully in the opening 30 of the frame 18. The transition from an open to a closed position of the window can be seen between figure 1A and 1B. Figure 1B corresponds to closed condition of the window and as can be seen, the trigger 108 has now been triggered by the catch 110 to compress the trigger 108 -as will be seen with reference to Figure 7 at least, it pivots to the compressed position, although it might be a linear actuation). In this embodiment, nevertheless, the trigger is in the form of a lever. The catch has triggered the right hand side of the left trigger (i.e. trigger 108 rather than trigger 108a). As a result, the right hand side of trigger of 108 has been forced into the edge of the window -hereinafter compressed. This in turn lifts a left side of the trigger 108, which releases a finger latch 420 on a body 150 of the shootbolt 122 (see Figure 7). The trigger 108 is thus realisably attached to the shootbolt 122, which shootbolt 122 is spring loaded into an extended positon. The shootbolt 122, which optionally comprises a guide block 106, thus then is released via compression of the trigger 108, whereupon the shootbolt extends, or moves/slides out of the corner block 103 to project away from the corner block 103 into the hole 102 provided in the corresponding corner keep.

The guide block 106, which is attached to the body 150 of the shootbolt 122, follows suit, to move from the recess 120 into a slot 104.

Advantageously, the guide block 106 can help to guide the shoot successfully into the hole or first receiver 102 by the slot for it having a wider opening than the pin of the guide block, with the slot then narrowing to align the guide block to the longitudinal centre of the slot. The shootbolt 122 can also have a chamfered end to assist it in entering the first receiver 102.

To improve automatic firing of the shootbolt 122 in response to the triggering of the trigger 108, a suitable biasing mechanism is employed such as a coil spring 128 (not visible). However, as the window will typically have a vertical arrangement, gravity could also serve to bias the shootbolt downwards when released by the trigger and finger latch 420. More typically, however, a spring bias will be provided to better ensure automatic engagement of the shootbolt and guide block, upon the trigger actuation.

The suitable spring in the housing 128 therefore biases the shootbolt 122 away from the trigger when the trigger has been moved to the open position. Numerous other ways of achieving this effect are possible, such as a magnetic or elastic effect.

The first receiver 102 is configured to receive the shootbolt 122 and similarly the second receiver 104 is configured to receive the guide block 106. In embodiments, the shootbolts (122 and 122a) extend from both the left and right hand side of the lock assembly 100a (as shown in figure 1 b), or from the top and bottom edges of the window as viewed in Figure 16.

Therefore, with this arrangement, by shutting the window (comprising the lock assembly 100a), a basic security level is achieved via the shootbolts (122 and 122a) and guide blocks (106 and 106a) entering the first receivers 102 and 102a and the second receivers 104 and 104a automatically.

Advantageously, this level of security is achieved by the user upon merely pushing or pulling the window shut, and as such it does not require the user to turn any handles or keys. As casement windows typically do not have a sprung central latch, unlike doors, this added security provides a novel benefit compared to standard double glazing casement windows.

Once the user has initially secured the window as shown in figure 1B, the user can further secure the window. This stage of further securing the window is shown in figure 1C. The user can further secure the window by turning a handle, connected to the gearbox 134. A latch, 136 which was positioned within the centre lock 114 proceeds to project from the centre lock 114 into a receiver 138 positioned in the centre keep 101b. The turning of the cogs in the gearbox 134 further causes the connectors 112 and 112a to move away from the gearbox. This is shown by the arrows 132 and 132a. This can further be visualised by the horizontal displacement evident for a link block 133a, 133b in on the connector 112 between the condition of Figure lb and lc. The outward movement 132 of the connector 112, which is connected to the trigger's mount, moves the trigger 108 outward too, so as to move it relative to the catch 110 of the keep 101, towards a free end of the catch 110. This can be seen in Figure lc and 4d and 4e, where the trigger moves from its compressed position (after releasing the shootbolt) into a longitudinally displaced position whereat the right hand side of the left trigger can return to a laterally extending condition. In this laterally extended condition, the trigger has passed beyond the free end of the catch 110 to allow that right hand end of the left trigger to sit adjacent the free end of the catch 110. The trigger is also at this point generally positioned in the recess 120.

It is noted that in figure 1C the shootbolt 122 and guide block 106 are still in their respective receivers 102 and 104 for latching the window in its closed condition. This is thus now in addition to any latch 136 being extended into a receiver 138 of the centre block (if present) due to the operation of the handle. The combination of these three security elements (i.e. shootbolt 122, guide block 106 and latch 136), and typically actually 5 elements, as shown, due to there being a shootbolt and guide block at each end of the window, provides an effective level of security, with the connectors 112, and the gearbox mechanism, effectively jamming the shootbolts and guide blocks in their extended and latched condition, thus locking the latches.

During this movement the trigger can engage with the body of the shootbolt again by the finger latch 420 once again engaging the shoulder on that body 150 as the trigger's right end extends outward (as that rotation likewise drops the finger latch into the recess therefor in the body 150, thus linking the trigger mount to the body again.

When the user wishes to open the window, the user must instead turn the handle which is connected to the gear box 134 in the opposite direction to reverse the movement of the connectors 112. The turning of the handle by the user in order to open the window causes the movement of gears, and thus the connectors 112, in an opposite direction to the previous "locking" movement of the connector 112. This "opening" movement thus moves the connectors 112 back towards the centre lock 114. Consequently, the trigger 108 and its mount retracts back into its initial position (of figure 1A) as shown at point 142. However, as the catch 112 would resist this movement if fixed, due to the trigger engaging the catch's free end, as the trigger reverts, it pushes the catch into a recess housing 148, as can be seen in Figure 1d.

During this movement, as the trigger has been reattached to the shootbolt's body 150 during the locking of the window as shown in figure 1C at point 130, the movement 144 of the trigger 108 back towards the centre lock 114 consequently moves the shootbolt 122 and the guide block 106 back into the edge of the window as shown in Figure 1d.

Subsequently, when the window is swung open, following this unlocking of the window, the catch 110 will initially be in its recess housing 148 and thus is not in a position to reactivate the trigger 108. However, once the window is swung open, this releases the catch 110 so that it can spring out of the recess housing in the corner keep, reverting to the initial condition of Figure la. The trigger thus will once again be activated when the window is once again closed.

This cyclic interaction of the trigger, catch, shootbolt and guide blocks repeat each time the window is pulled closed, locked by first operation of the handle, unlocked by second operation of the handle and then finally pushed open to allow reset of the catch 112.

Figures 2a and 2b show two perspective views of the corner keep 101 and the corner block 103. Both of the views relate to the condition of these components as shown in figure 1C. The locking mechanism is in a latched and locked position, with the shootbolt 122 extended into the first receiver 102, the guide block 106 extended into the second receiver 104 And the trigger with its right end raised to sit in front of the free end of the catch 110 (in the recess120). In this embodiment, the first receiver is a hole that extends through a side flange of the corner keep 101. It is a through-hole, but in other embodiments the first receiver may be a blind hole or recess that only indents into the corner keep 101, rather than extending all the way through.

Figure 2a shows the recess housing in a catch house 212, which selectively houses the catch 110, and a spring for biasing the catch to the extended position thereof. Figure 2b instead is a cut away view that does not show the catch house 212, but only shows the corner block 103 and the end part 214 of the corner keep. By this cut-away view, the second receiver 104 can be seen clearly to be accommodating the guide block 106. The second receiver is shaped with a ledge 230 that catches a ridge 216 of the guide block 106. A stem of the guide block extends through a slot of the second receiver 106. The ledge 230 of the guide block 216 can be in contact with the ridge 216, or spaced above it. and the ledge stops the window simply being pulled open by jamming the window and frame apart..

From Figure 2b it can be seen that the tip of the trigger 108 has a chamfered side edge 210. This preferred feature can work in conjunction with a chamfered side edge 230 of the catch 110 such that the two chamfered edges 210 and 220 assist a triggering of the trigger by the catch as the chamfered edges can ride over one another in response to a closing force when the window is being closed as in Figure lb. The two angled edges 210 and 220 provide a normal force that compresses the free end of the trigger 108 (to pivot it) and thus eventually cause the release of the shootbolt 112, as per Figure lb. The corner block 103 further comprises openings 222. The openings 222 may be configured for receiving fixing screws, or other fixing members to attach the component to the casement window 20, such as a PVC window. The holes can be seen to be countersunk on their outside face in Figure 2a. Similarly, one or more opening 224 on the corner keep may be provided for use to fix the corner keep to a wall or in a frame of a wall, again by screws or the like.

Figures 3a to 3d show the corner keep 101 with its catch 110 and the catch housing 212. Figure 3a shows the catch 110 in a catching position -external of the catch housing, as per Figure la. Figure 3b shows the catch in that same condition, but with the catch housing removed to show the whole catch.. The catch 110 has an indented section 310 at its free end to provide for a surface that the free end of the trigger can contact when the trigger moves past the free end of the catch during the locking process of Figure lc.

Figures 3c and 3d instead show the corner keep 101 when the catch 110 has been slid into the catch housing -with Figure 3d showing the catch housing cut-away.

These correspond to the condition of Figure 1d.

From Figures 3a to 3d, a catch biasing means 314 can be seen to be extended when the catch 110 is in the catching position in figure 3a. The catch biasing means 314 can be seen to be compressed into the catch when the catch 110 is in the housed position in figure 3d.

Figures 4a to 4d show the progression of the locking mechanism in more detail.

They include three side profile views with three states and two further side profile cut away views showing two further states. The latter two views omit a carrier casing 411 to better illustrate the interaction of the trigger 108 with the catch 110 and the body 150 of the shootbolt. Figure 4a corresponds to the locking mechanism as shown in figure 1A where the locking mechanism is retracted and the window is slightly open to allow the trigger 108 not to be compressed. As the window 20 is not yet closed, the trigger 108 is extended to a position behind the side of the catch 110 and no shootbolt 122 is visible (and the guide block 106 is retracted to be located in the recess 120.

Figure 4b shows the moment when the window is initially closed and the trigger 108 has just been compressed. Although the trigger 108 is compressed, the shootbolt 122 (and thus the guide block 106) has not yet had time to extend to their latching positions. The extension of the shootbolt 122 and the guide block 106 upon the subsequent extension (due to a spring bias, upon release) is shown in figure 4c where it can be seen that the shootbolt 122 and guide block 106 have extended into the first receiver 102 and second receiver 104 of the corner keep 102.

As described above, in the initial position shown in Figure 4a, the trigger 108 holds the shootbolt 122 and the guide block 106 to prevent them from firing into their latching positions. Once the trigger 108 has been compressed by the catch 110, however, the shootbolt 122 and guide block 106 extend due to a shoot biasing device such as a spring. This extended position of Figure 4c corresponds to the view shown in figure 1B.

The internal view of Figure 4d corresponds to figure 1C, although the carrier casing 411 has been removed to better show the trigger 108. In this view, the user has locked the window by turning the handle 26, which not only releases a further catch (not shown) into the centre keep 101b, but further moves the trigger 108 in a distal direction (i.e. away from the centre keep 116). During the movement to the position of Figure 4d from the position of 4b the trigger 108 slides under the moveable catch 110 to extend beyond it. When clear of the catch 110, as per Figure 4d and then 4e, a trigger biasing device such as a spring brings down the (as shown) left end of the trigger 108 and lifts the right end -pivoting it around its pivot 704 such that a final position of the trigger due to the trigger biasing means has the bottom edge 420 of the trigger 108 contacting a lip 422 of the shootbolt 122 so as to act as an attaching mechanism that attaches the trigger 108 to the shootbolt 122.

A similar action occurs at the other end of the lock mechanism for the other corner of the window.

Figures 5a to 5e show this same series of progression, but with different parts removed to show further details of the various interactions between the components of the shootbolt end section 103. Figure 5a shows the corner block 103 and locking mechanism 100 in the same condition as in Figure 4a, with the window 20 about to close, whereby the raised right end 428 of the trigger 106 is located in front of the catch 110. Figure 5b then shows the window after closure, but before firing of the shootbolt figure 5c being after firing. The latter position occurs effectively immediately after the latter. Figure 5b corresponds to Figure 4b, but has the carrier casing 411 removed to show the condition of the trigger -with the right end 428 now pushed down (or into the edge of the window) by the inter-engagement thereof with the catch 110. In this internal view of Figure 5b it can clearly be seen that the left end 420 of the trigger 108 has detached from a recess 510 in the body 150 of the shootbolt to release the shootbolt by the bottom edge 420 of the trigger 108 raising above the upper edge 512 of the recess 510. Due to the shoot biasing means 424 which is shown as a spring in a compressed state in figure 5b, when the bottom edge 420 of the trigger 108 is raised above the upper edge 512 of the recess 510, the shootbolt becomes free to extend outwards, i.e. away from the centre keep, into its window latching state. This extension can be seen in figure 5c where the shootbolt 122 now extends out from the edge of the lock assembly into the receiver or hole 102 of the corner keep.

By comparing figures 5b and 5c, it can be seen that the shoot biasing means 424, which in this embodiment is the spring, has gone from a shortened compressed state in figure 5b to an lengthened extended state 503 due to the release of the body of the shootbolt by the trigger 108. It can be a coil-spring for this purpose, although other sprung mechanisms can alternatively be used. The spring 424 is visible in figures 5b and 5c as these figures omit the cover and the trigger mount 514 that retains and pivotally mounts the trigger 108 in the end section 103 (pivotably mounted about a pivot pin 515 as shown in for example Figure 5e). The trigger mount 514 also connects the trigger to the centre gearbox 105 via a linkage including the link member 112 (e.g. via a linkage arrangement to allow length variations by adding or removing sections or adjusting via an adjustable link -here a sawtooth adjuster 213 (see Figure 9) . As can be seen in figure 5d, and Figures 7 to 15, the various parts of the link member 112 generally extend parallel to the edge of the window, and in this embodiment they are connected to the trigger mount 514 to slide together when the handle is operated. The link member 112 can slide relative to the housing by virtue of a slot 517 which slides either side of a boss 519 which is fixed to the housing by two rivets 518. Referring to Figure 7, the link member 112 has a hole at its end to fit on a further boss 520 on the trigger mount 514 to link them fixedly together. As Figure 7 is a cut through the trigger mount 514, a cavity 521 for the trigger 108 is clearly visible.

The trigger mount 514 has a further slot 523 (one half side of which is visible) through which a fixation screw (not shown) can extend when joining the end section 101 to the corner of the window 20. Pre-drilled screw holes 524 are provided for these fixation screws -in three locations for this embodiment.

Figures 6a to 6e show the progression of the locking mechanism during unlocking and unlatching, for window opening -i.e. operation of the handle once the trigger is re-engaged with the body of the shootbolt, as per Figures 4e and 5e to retract the shootbolt 122 and to reset the catch 110. Figure 6a corresponds to the condition of Figures 5e and 4e, so the shootbolt 122 is extended into the first receiver 102 of the corner keep and the trigger is extended such that its right end as shown is extended to the edge of the door and outward from the side of the door so as to put its right end 428 on position at the tip of the catch 110, under the bias of the trigger spring. The catch is likewise extended to its default position. The window is closed, latched and locked.

Figure 6b shows the shootbolt 122 slightly withdrawn back into the edge of the window (by turning the handle slightly) whereby its free end has exited the first receiver, although the guide block will still be captured in the second receiver 104 until the handle is further turned, so the window remains latched. As can be seen, turning the handle is drawing back the shootbolt 122 and the guide block, and the body and the trigger, as seen in Figure 4e, the trigger's left end is engaged with the body 150 of the shootbolt 122.

The cover is off in this figure, although the trigger mount is present, and the catch can be seen to be starting to compress back against the catch biasing means or spring 314. The catch biasing means 314 biases the catch into an extended position (i.e. into the catching position) by default, which position is shown in figure 6a. In figure 6b, the catch is slightly compressed against the spring 314.due to the retraction force of the trigger against the tip thereof Figure 6c shows the shootbolt fully retracted clear of the edge of the window and as a result of the movement of the trigger 108 and the shootbolt to this position, away from the corner keep, due to a user fully turning the handle for the gearbox mechanism 134, the guide block 106 has been retracted from the second receiver 104, or slot, into the recess 120 of the corner keep. As the casing is not shown, the corner keep looks like two pieces, but they will be linked together by the casing of the corner keep in the fitted product.

As can also be seen the spring 314 is fully compressed.

The user may interact with the gearbox 134 to operate this retraction of the shootbolt and guide block by turning the handle (or sometimes a key) in the centre block 105. The shootbolt mechanism is then caused to be retracted because the trigger 108 is retracted via the connector 112, and the trigger is engaged with the body of the shootbolt via the bottom edge 420 of the trigger in connection of the lip 422 of the shootbolt, as seen in Figure 4e.

Figure 6d corresponds to Figure 6c, but has the casings re-included. There are thus shown the catch housing 212 and the corner block housing 411.

Figure 6e then shows what happens upon opening the window from the unlatched condition of Figure 6d -upon movement of the lock assembly 100a from a closed and unlocked position to a window open position, whereby the trigger swings out of the recess 120 to release the tip of the catch 110, there results the extension of the catch 110 back out to an extended condition, as shown in figure 6e (i.e. the catch returns to the default "catching" position). It is thus out of its housing 212, compared to the retracted position of the catch 110 shown in figure 6d (in which the catch is in the housing 212).

Referring next back to Figure 7 the corner keep 101 and the lock assembly 100aare shown -in section through the longitudinal centre, in the unlocked and unlatched, ready to open, shootbolt withdrawn condition. As this is a sectional view, the spring for the catch can be seen over a support pin. The withdrawn position corresponds to when the shoot 122 is within the corner block 103, rather than extending out the edge of the window. Furthermore, the shoot biasing means 424 is in a compressed position as the trigger is retained onto the body of the shootbolt. The catch 110 is in the housing therefore with the spring compressed too.

Figure 7 corresponds to figures 6c and 6d. In other words, the trigger 108, body, shootbolt and guide block are in the retracted position, and the window is in the closed position -ready to be opened.

In the displayed embodiment, the trigger 108 is a lever comprising a top edge 428 and a bottom edge 420. The trigger 108 comprises a pivot point 704 about which the top edge 528 and bottom edge 420 pivot. It can be seen that the trigger 108 is contacting the catch 110 at a catch contact point or tip 702 on the top edge 428 of the trigger. It is via contact at the catch contact point 702 that the trigger is able to move the catch into the housing therefor, such that the catch is displaced so as not to be able to re-trigger the trigger 108.

The bottom edge 420 of the trigger 108, in this condition, contacts and holds the shootbolt 122 at a shoot contact point 706. The contact at the shoot contact point 706 is what allows the handle to withdraw the shootbolt 122 into the withdrawn position (via the movement of the link member 112 by the gearbox).

Figure 8 shows a half-cut view of the whole locking mechanism 100, still in the condition of Figure 7. As can be seen the two ends of the locking mechanism largely mirror each other.

Figure 8 shows the gearbox 134 comprising the opening 118 for a handle. The gearbox 134 comprises a main cog 804 that comprises an opening 118 for a handle. The cog 804 is rotated by the user of the window by turning the handle. The gearbox translates the rotational movement of that main cog into a lateral movement of the link members 112 and 112a via a gear arrangement, as known in the art. The connectors 112 and 112a move in opposite directions to mirror each other -moving away from the centre block 105 to lock the locking mechanism or both move towards the centre block 105 to unlock and unlatch it.

Figure 9 shows whole locking mechanism 100. Figure 9 again shows connectors 112 and 112a, but more clearly show the adjustment mechanism comprising sawtooth sides on a first member and a sawtooth insider wall pair on a connector therefore so that the inner member can be fitted in any one of multiple positions relative to the outer part -thus allowing the mechanism to fit windows of different heights.

Figure 9 likewise shows the locking assembly in a retracted position as the shoots are not extended into the first receiver 102 (although the triggers and gearbox cannot be seen).

The centre keep 101a comprises two centre keep receivers for receiving two centre guide blocks that can extend out of the gearbox when the centre gearbox is turned into a locked position. Such movement is well known in the art and not the subject of this invention.

Figure 10 shows a side elevation view of the locking mechanism 100 of Figure 9. In figure 10 it can be seen that the trigger 108's chamfered edge 210 at the top edge 428 of the trigger 108 engages a chamfered edge 230 of the catch 110 to allow smooth release of the trigger into the lifted position in the step between Figures 4d and 4e.

Finally, referring to Figure 11 a window is shown incorporating the locking mechanism described above. Although shown schematically, the window has top and bottom edges from which the shootbolts 122 can be extended, and a side from which the guide block 106 extends. The window fits within a frame 18 in which top and bottom end keeps are provided along with a central keep for opposing the gearbox of the lock mechanism. The gearbox is operated by the handle 26. This window is hinged at one end by a pair of hinges 28. The invention may instead be fitted to a pair of windows that have facing sides, or other casement window forms, with top hinges for example.

In summary, therefore, the present invention provides a locking mechanism for securing a window, the locking mechanism configured to have a lock assembly that is attachable to said window, the lock assembly comprising: a trigger comprising a triggering point; a shoot; a shoot biasing means configured to bias the shoot towards the extended position; a trigger biasing means configured to bias the trigger towards the closed position; and a connector configured to mechanically connect the trigger to a driving mechanism, wherein the driving mechanism controls a position of the trigger within the first range of motion, and the trigger being for selective engagement against a moveable catch on a keep section for the lock assembly, e.g. in the frame for the window.

The invention is described above with reference to it being a window multi-point lock. It could likewise be used on a door as a door multi-lock system.

The invention also resides in the method of operating the locking mechanism as described above -for opening (unlocking) or closing (latching and subsequent locking) the window.

The present invention has been described above purely by way of example. Modifications in detail may be made to the invention within the scope of the claims appended hereto.

Claims

CLAIMS: 1. A locking mechanism for selectively securing a window in a closed position, the locking mechanism comprising a lock assembly configured to be attachable to said window and a keep section for the lock assembly to latch within, wherein: the lock assembly has at least one sprung latching member and the keep section comprises at least one receiver for selectively accommodating the sprung latching member to latch the lock assembly within the keep section to secure the window in the closed position; the keep section further comprises a moveable catch; and the lock assembly further comprises: a trigger comprising a free end, the trigger configured to: a) pivot between a free-end-retracted condition and a free-end-extended condition, the pivoting defining a first range of motion; and b) slide between an inner position and an outer position, the sliding defining a second range of motion; and the trigger being configured to selectively engage the moveable catch as the window is being closed to then trigger the sprung latching member so as to fire the sprung latching member into a latching state, and to subsequently interact with the movable catch to move the moveable catch from a catching position to a reset position when the window is being unlatched.
2. The locking mechanism of claim 1, wherein a side of the free end bears against a side of the moveable catch when the window is being closed such that said trigger engages the moveable catch to trigger the spring latching member.
3. The locking mechanism of claim 1 or claim 2, wherein the trigger slides from the inner position to the outer position upon operation of a handle of the locking mechanism in a first direction.
4. The locking mechanism of claim 3, wherein the trigger slides from the outer position to the inner position upon operation of a handle of the locking mechanism in a second direction.
5. The locking mechanism of any one of the preceding claims, wherein the trigger is adapted to interacts with the moveable catch to move it from said catching position to said reset position as the trigger slides back from the outer position to the inner position while the window is closed.
6. The locking mechanism of claim 5, wherein the free end of the trigger interacts with an end of the moveable catch when moving it from said catching position to said reset position during the unlatching process.
7. The locking mechanism of any preceding claim wherein the movable catch moves under a housing of the keep section when it moves to the reset position.
8. The locking mechanism of any preceding claim, wherein said sprung latching member is attached to a second, retracted part of the trigger when the trigger is in said free-end-extended condition, and it fires by the second part pivoting away from the latching member as the trigger moves towards its free-end-retracted condition extending.
9. The locking mechanism of any preceding claim wherein the sprung latching member comprises a linearly sliding shootbolt with a spring bias adapted to drive the latching member towards an extended position.
10. The locking mechanism of claim 9 wherein the shootbolt has a free end that engages into a receiver of the keep section upon it firing, the engagement comprising an extension of the shootbolt's free end from the edge of the window into the receiver.
11. The locking mechanism of claim 9 or claim 10, wherein the receiver is a through hole in the keep section.
12. The locking mechanism of any one of claims 9 to 11, wherein the sprung latching member further comprises a guide block configured to fit into a guide channel of the keep section.
13. The locking mechanism of any one of the preceding claims wherein the keep section comprises a corner keep, the receiver being in the corner keep, and the sprung latching member being arranged to fire such that it then engages the receiver in that corner keep.
14. The locking mechanism of claim 13, further comprising a second corner keep like the first and a second lock assembly therefor, the second lock assembly being like the first in having a sprung latching member and trigger.
15. The locking mechanism of any preceding claim further comprising a central gearbox for mounting in the window, the gearbox operable by a handle or key, the gearbox being for driving movement of the trigger along the second range of motion via one or more interconnecting link member.
16. The locking mechanism of claim 15, wherein the central gearbox comprises a central latching member for selectively extending into a centre keep.
17. A window fitted with a locking mechanism as defined in any one of claims 1 to 16.