WO1998041719A2

WO1998041719A2 - Window or door latching mechanisms

Info

Publication number: WO1998041719A2
Application number: PCT/GB1998/000737
Authority: WO
Inventors: Jack Whittaker Stevens; Kenneth Fredrick Johnson; Andrew Tomlinson
Original assignee: Schlegel Systems, Inc.
Priority date: 1997-03-14
Filing date: 1998-03-12
Publication date: 1998-09-24
Also published as: GB9705317D0; AU6409698A; WO1998041719A3

Abstract

The present invention relates to latching mechanisms for windows or doors and more particularly to pivoting or sliding windows or doors incorporating uPVC frame members into which latching/locking components such as operating handles, rack and pinion drive mechanisms, deadlocking mechanisms, shoot bolts and latches, espagnolette drive mechanisms and latching mechanisms and the like, can be fitted or housed. The mechanism comprises a shoot bolt (7), a latch plate (23) adapted to receive the shoot bolt and a means (17) to define a slot (20) for the latch plate to locate into. A secondary latching mechanism is provided by a pivotal member (47) adapted to be mounted on a frame for the window or door. A shoot bolt of the latching mechanism may be connected to drive member therefor by a turnbuckle device (79).

Description

Window or Door Latching Mechanisms

The present invention relates to latching mechanisms for windows or doors and more particularly, to pivoting or sliding windows or doors incorporating uPVC frame members into which latching/ locking components such as operating handles, rack and pinion drive mechanisms, deadlocking mechanisms, shoot bolts and latches, espagnolette drive mechanisms and latching mechanisms and the like, can be fitted or housed.

Nowadays, there is a requirement in the building industry, both for new buildings and for retrofitting or refurbishments, for windows and doors which have minimum upkeep and maximum security and maximum weatherproofing; double or triple glazed windows and doors with uPVC frame members and multi-point locking features satisfy these requirements. The latching mechanisms of the present invention have been designed for use in such windows and doors, although they could be used in wooden, metal or composite window or door constructions.

It is well known in many door and window constructions to provide two latching bolts which are moved in opposite directions, by a single operating handle, into keeps formed in the frame for the door or window, either above and below, or to the left and right of, the window sash, respectively. While such bolts in combination with their keeps provide better security than a single latch in the leading edge of the door or window sash, they suffer from the disadvantage that they can be forced open when in their latching position, often even when deadlocked, by the insertion of a jemmy or other levering device between the sash and frame to cause bowing of the leading edge of the sash frame member in which the bolts are located, to such an extent that the distance between the outer extremities of the bolts will be reduced sufficiently to move them out of the confines of their keep, whereupon the sash can be opened. It is one of the objects of the present invention to overcome this deficiency.

Most window and door sashes manufactured from uPVC frame members have frame members which are extruded from uPVC to the desired cross-section to accommodate weather seals and to cooperate with an extruded uPVC frame and the extrusions are hollow so that they can be reinforced internally with metallic reinforcement to strengthen the uPVC material. Normally, welded mitre joints are provided at the junction between the horizontal and vertical frame members of the window or door sash and latching bolts and the like are accommodated in a groove in the outer face of the extrusion, which can be closed off with a snap-fit closure member. It is normally necessary to drill one or more apertures through at least one of the extrusions making up the frame of the sash and/or in the frame for the sash to accommodate an operating handle, keeps for the bolts, (to allow the bolts to latch satisfactorily by moving a sufficient distance into the frame) perhaps a deadlock or lock mechanism of another sort, and perhaps also to accommodate on the opposite side thereof one or more hinges. However, it is preferred to keep the number of apertures formed in the extruded uPVC material to an absolute minimum to retain strength and to reduce the possibility for the ingress of moisture which can result in the metal reinforcement corroding. Accordingly, the fewer locking components which are accommodated in the extruded uPVC members the better. As previously mentioned, the uPVC extrusions normally have an external groove formed in their outwardly facing face to accommodate espagnolette bolts, lock bolts etc., and there is almost always an air gap between the opposed faces of the sash itself and the frame for the sash, and it is a further object of the present invention to make use of this groove and the air gap to provide one or more further latching or locking locations for the window or door. Traditionally, the shoot bolts used for locking or latching uPVC window sashes in their closed position are manufactured separately from their operating handles and associated locking mechanisms and are joined together either when the window sash or door is fitted or alternatively, prior to leaving the window factory. Typically, different types of operating mechanism and locking mechanism can be used with various different constructions and sizes of shoot bolts, the size of course, depending very much upon the size of the window sash or door. Accordingly, there is a requirement for a quick, simple and inexpensive means of connecting one or more shoot bolts of the desired construction and length to the operating mechanism for the bolts e.g. the shoot bolt drive mechanism. It is a further object of the present invention to provide such a connecting means.

According to a first aspect of the present invention, we provide a latching mechanism for latching a panel such as a door or window sash in a closed position in a frame therefor, comprising a shoot bolt adapted to be mounted on the sash and moveable between a withdrawn position and an extended latching position, a latch plate adapted to be » secured to the frame for the panel and having an aperture cX keep portion for receiving a free end of the shoot bolt, and means adapted to be mounted on the sash defining a slot across which the free end of the shoot bolt passes when the latter is moved between its withdrawn and latching positions, said slot being arranged, when the panel is in a closed position, to receive the apertured keep portion with the aperture therein in line with the shoot bolt, there being a further aperture in the means defining the slot to receive the free end of the shoot bolt when the latter in its extended locking position.

Preferably, the latch plate is L-shaped with one arm of the L having apertures therein for connecting the latch plate to the frame, and the other arm of the L providing said apertured keep portion. Preferably also, the means defining the slot comprises a security plate secured to an edge face of the panel and having an end portion in which said further aperture is formed, which end portion together with said end face of said panel defines said slot to receive the keep portion of the latch plate.

Preferably, the latching mechanism, with the exception of the latch plate, is mounted on face edge portions of the frame of the door or window sash, with the shoot bolt sliding longitudinally in a groove formed in one face and its free end portion sliding within a corner guide located in the grooves at the corner of the sash frame. The corner guide may engage within the grooves with a snap-fit. For the purpose, the corner guide may be provided with grooves and ribs for snap-fitting engagement with respective ribs and grooves on the frame member. Preferably, also, the corner guide is designed so that the means defining the groove, e.g. the security plate nests in a face thereof and can be locked in position by clamping screws which are used to secure the corner guide to the frame.

By arranging for the latch plate to be located in the groove, i.e. between the security plate and corner member on the frame and by passing the shoot bolt through apertures in both plates to latch the panel, a double shearing of the bolt, or of both plates will have to occur before the latched panel can be forced open. Also, there is no need to force apertures in either the sash frame or the frame for the sash to receive the end of the shoot bolt.

According to a second aspect of the present invention, we provide a latching mechanism for a panel such as a door or window sash for latching the sash in a closed position in a frame therefor, the latching mechanism comprising a shoot bolt adapted to be mounted for sliding movement in an edge face of the panel and a secondary latching member adapted to be mounted on the frame for the panel and to be actuated by movement of the shoot bolt to a latching position, the secondary latching member being moveable between a withdrawn position and a latching position in which a locking nose thereon engages in a recess provided in the panel.

Preferably, the shoot bolt is adapted for mounting in a groove formed in an edge face of a frame member of the sash, and with its end portion passing through at least one guide aperture on the corner of the sash frame. Preferably, the mechanism includes a corner reinforcement having two aligned apertures providing said guide aperture for the shoot bolt. Preferably also, the secondary latching member is in the form of a bell crank lever, pivotally supported in a housing adapted to be mounted on the frame for the panel, the bell crank lever being supported on a pivot pin in the housing and being biassed to a withdrawn non-latching position by a spring and moveable by the shoot bolt when the latter is moved to an extended latching position engaging a first arm of the bell crank lever to move it against its spring bias from its withdrawn position to a latching position in which a second arm of the bell crank lever is moved to a latching position such that a locking nose thereon engages with the recess in the panel. Preferably, the recess in the panel is provided by a groove in an end face of a frame member of the panel. Preferably also, a secondary latching aperture is provided in the corner reinforcement for the panel, said secondary latching aperture overlying said recess and being aligned to receive the locking nose of the secondary latching member.

Preferably, the panel is made up of uPVC frame members having grooves in its edge faces which frame members are joined at each corner of the panel by mitre joints and welds and the corner reinforcement is of generally L-shaped construction and is located in the said grooves.

Preferably the housing has recesses therein to receive the bell crank lever and the free end portion of the shoot bolt, apertures to receive the pivot pin and further apertures for screws or the like by means of which the housing can be secured to the frame for the panel.

Preferably, the housing is sufficiently slim to be mounted on the face of the frame for the panel facing the panel, in an air gap between the panel and frame therefor, so that there is no need to form holes in the frame to receive the shoot bolt. Preferably, the throw of the nose of the second arm of the bolt crank lever is greater than the throw of the shoot bolt.

Both the first and second aspects of the invention could be provided in kit form.

According to a third aspect of the present invention, we provide a latching mechanism for latching a panel in a closed position in a frame therefor, the mechanism comprising a shoot bolt and an operating mechanism therefor, wherein an end portion of the shoot bolt is connectable to a drive member of the locking mechanism by a turnbuckle device. Preferably the turnbuckle device comprises an elongated aperture in one of the shoot bolt and drive member and a turnbuckle on the other of the shoot bolt and drive member, the turnbuckle having a swivelling head designed to pass with a close fit through the elongated aperture when in a particular orientation but when swivelled to any other orientation, not to pass through said elongated aperture. Preferably, a circular recess generally concentric with the elongated aperture is provided in a face of whichever of the shoot bolt and drive member the aperture is formed, the recess having a depth at least equal to the depth of the swivelling head so that when the head has been swivelled to an orientation in which it will not pass through the elongated aperture, its upper face is not proud of the upper face of whichever of the shoot bolt and drive member the aperture is formed within. Preferably, the aperture is formed within the drive member and the turnbuckle is formed on an end portion of the shoot bolt, which end portion is stepped to receive an end portion of the drive member within which the aperture and recess are formed, the stepped portion having the turnbuckle formed thereon. Preferably, the shoot bolt is adjustably connected to the remainder of the shoot bolt so that the length of the shoot bolt can be adjusted.

It will be appreciated that each of the three aspects of the present invention which have been described above can stand alone or be used together and accordingly, any one of the described mechanisms can comprise a preferred feature of one or both of the other mechanisms.

In all cases, the above described mechanisms do not require apertures to be formed in the frame members of the sash and frame therefor, because they can be accommodated in the grooves in the end face of the sash frame members and in the air gap between sash frame members and frame members.

The three aspects of the present invention are now described by way of example with reference to the accompanying drawings in which: -

FIGURE 1 is a perspective view of a corner of a window sash located in a frame, only the corner of which is shown, in accordance with the first aspect of the invention,

FIGURE 2 is a transverse section through a frame member of a window sash and a frame therefor adjacent a corner of the frame member and frame, of a second aspect of the present invention,

FIGURE 3 is a section through the locking mechanism shown in FIGURE 2 along the line III-III, FIGURE 4 is a perspective view to an enlarged scale showing the locking mechanism of FIGURES 2 and 3 and,

FIGURE 5 is a perspective view showing part of a latching mechanism according to the third aspect of the present invention.

Referring to Figure 1, a corner of a panel 1 is illustrated, the panel being made up of a first frame member 3 and a second frame member 5 which may be welded together at the corner of the panel e.g. with a mitre joint (not shown) the panel typically being a window sash or a door, such as a patio door glazed with glass (not shown) supported by the frame members 3 and 5. Typically, the frame members 3 and 5 are extruded from uPVC material and may have a cross- section such as shown in Figure 2, but they could be of any other cross-section or even be formed of wood, metal or a composite construction. If they are formed of uPVC, they would be internally reinforced with one or more reinforcement strips such as the strip 4 shown in Figure 2. In its end face, each frame member 3,5 has a groove 6 formed therein such as shown in Figure 2 , the groove being sufficiently deep and wide to accommodate a shoot bolt 11 for sliding movement therein as depicted by the arrows 12. Sliding movement of the shoot bolt 11 is effected in known manner e.g. by means of an operating mechanism such as a handle for the window or door panel which, when twisted, causes a pinion engaging with a rack to move a drive member longitudinally to drive the shoot bolt 11.

As illustrated, the shoot bolt 11 is slidably supported adjacent its free end in a corner guide 7 of generally L- shaped construction and which forms a snug fit within the grooves 6 at the corner of the panel 1. The corner guide 7 may be provided with grooves 9,15 and with ribs 13,16 which form a snap-fit with cooperating ribs and grooves (not shown) in side faces of the grooves formed in the frame members 3,5 respectively. Associated with one limb of the corner guide 7 is a security plate 17 which, as illustrated, has an outwardly kinked end 19. Preferably, a major part of the plate 17 forms a snug fit within a recessed portion 18 of the said one limb of the corner guide 7 but the kinked end 19 is sufficiently kinked outwardly so that its internal face defines with an end face of the corner member 7 an elongated slot 20. The kinked portion 19 of the security plate 17 has an aperture (not shown) formed therein to receive the tip 25 of the shoot bolt 11 when the shoot bolt has been moved to a fully extended latching position as shown in Figure 1. Such movement moves the bolt tip 25 across the slot 20.

A latch plate 21 forms part of the latching mechanism. The latch plate 21 is generally L-shaped with a first arm of the L having two apertures 27 formed therein to receive screws or the like by means of which the latch plate may be secured to a face of the frame for the panel 1. The other arm of the L-shaped latch plate comprises a keep portion 23 designed to be located within the slot 20 when the latch plate has been correctly fitted to the frame.

The keep portion 23 has an aperture therein so that when the panel 1 has been moved to a closed position by pivoting the panel about a hinge or hinges in known manner, the aperture will line up with the aperture in the kinked end 19 of the security plate 17 and allow the tip 25 of the shoot bolt 11 to pass therethrough.

Preferably, the security plate 17 is secured in position by means of a pair of screws or bolts passing through apertures (not shown) therein aligned with apertures 29 in the corner member 7 and by means of which the corner member is firmly secured in position within its grooves 6 in the frame members 3 and 5 respectively.

By providing not only a keep portion 23 secured to the frame for the panel 1, but also a security plate 17 secured to the panel 1 considerably enhanced security is provided when the panel 1 is closed and the latching mechanism is in a latched position because, if an attempt is made to force open the latched panel using a jemmy or lever to foreshorten that edge of the panel in which the shoot bolt 11 is slidably supported so as to cause the tip 25 of the shoot bolt 11 to be pulled out of the aperture in the keep portion 23 of the latch plate, this cannot happen because of the presence of the kinked portion 19 of the security plate 17 on the far side of the keep portion 23 of the latch plate 21. By being sandwiched between the kinked portion 19 and the end face of the corner member 7 in the slot 20, the keep portion 23 affectively prevents foreshortening of the frame member 3 and it is therefore impossible for the tip 25 of the shoot bolt 11 to be pulled out of the keep portion 23. Furthermore, because the bolt is supported by the sash member on both sides of the keep portion 23 a double share failure would have to occur before security was breached or alternatively, the security plate 17 would have to break way from the corner member 7.

Also, all the component parts of the mechanism can be located in the groove 6 and in the air gap between the frame member (s) 3,5 of the sash and the frame for the sash.

Referring now to the second aspect of the invention, reference is made to Figures 2 to 4. As can be seen from Figure 2, an extruded uPVC frame member 3 is illustrated in which a shoot bolt 41 is slidably supported somewhat in the same manner as the shoot bolt 11 in Figure 1. At the corner of the frame of the sash shown generally at 40 in Figure 3 (the corner being formed by a mitre joint between frame members 3 and 5) a metal corner reinforcement plate 43 is provided, this plate 43 being more clearly visible in Figure 4. Plate 43 has two aligned apertures 44 formed therein through which an end portion 42 of the shoot bolt 41 can pass when the shoot bolt 41 is slid from a withdrawn position to an extended locking position which is the position shown in Figures 3 and 4.

While the shoot bolt 41 and the reinforcement plate bolt form parts of the latching mechanism of Figures 2 to 4, the major part thereof is supported on the frame for the panel, only part of which frame is shown at 45. Supported on the frame 45 is a secondary latching member 47 in the form of a bell crank lever having a first arm 49 extending to one side of a pivot 53 for the bell crank lever and a second arm 51 extending to the opposite side and terminating in a locking nose 52. The bell crank lever 47 is pivotally supported by the pivot pin 53 in a housing 57 and is biased in a clockwise direction to a position in which the arm 51 and nose 52 do not project from the housing 57, by a spring 55. The housing 57 has a recess 61 formed therein to receive the bell crank lever 47 and, adjacent a lower end thereof, the recess is widened as shown at 63 to receive the end portion 42 of the shoot bolt 41 when the latter is moved to a latching position. The housing 57 is secured to the frame 45 by means of screws or studs passing through apertures 59 provided for the purpose. As can be seen from Figure 3, the housing 57 is located wholly within an air gap A between the frame 45 and the frame member 5 of the sash.

As will be appreciated, the shoot bolt 41 is located in a groove 6 in the edge face of the pivoting window or door sash and when the bolt 41 is in a withdrawn position, the end face of its end portion 42 will be substantially flush with the outer face of the corner reinforcement 43, i.e. not projecting therefrom as shown in Figures 3 and 4. Under these conditions, the spring 55 will have caused the bell crank lever 47 to pivot clockwise from its illustrated position so that the arm 51 and nose 52 are within the confines of the recess 61. This will allow the window or door sash to be pivoted to a closed position or opened from that position. When it is desired to latch or lock the sash in its closed position, the shoot bolt 41 is operated to move it to the right as shown in Figure 4 , so that the end portion 42 will move to a latching position in which it engages within the enlarged portion 63 of recess 61, and at the same time the end portion 42 will move into engagement with the arm 49 of the bell crank lever, thus pivoting the bell crank lever 47 anti-clockwise against the bias of the spring 55 and causing the arm 51 and nose 52 to move out of the confines of the slot 61 and into engagement with a recess provided by the groove 6 in the end face of the frame member 5 of the sash. To provide additional security, the corner reinforcement 43 as well as having the aligned apertures 44 therein through which the shoot bolt 41 can slide, is also provided with a keep aperture 65 sized sufficiently large to accommodate the nose 52 and leading end of the arm 51 of the bell crank lever 47. Thus, actuation of the shoot bolt 41 to lock or latch the sash causes actuation of the bell crank lever 47 to move it into a sash latching or locking position and the provision of the corner reinforcement 43 through which both the shoot bolt 41 and the locking nose 52 pass provides a very secure fastening at two spaced locations, without having to drill apertures in either of the frame members 5,45.

By using the shoot bolt 41 which locates in one edge groove 6 of the frame member of the sash and by having the pivoting bell crank lever 47 supported in its housing 57 on the frame 45 which is moveable into another groove 6 of the sash frame, there is no need to fit a locking member into a frame member of the sash frame, thus weakening the sash frame and perhaps even causing reinforcement therein to corrode due to ingress of moisture. Thus double latching is provided by actuation of the shoot bolt alone, and furthermore, by using a bell crank lever, a small throw of the bolt 41 can be increased to a larger throw of the locking nose 52.

Referring now to the third aspect of the present invention, reference is made to Figure 5 which shows schematically a shoot bolt 71 of adjustable length attached by means of a turnbuckle device 79 to a drive member 75 of a shoot bolt drive mechanism 73. The drive mechanism 73 is largely of standard construction and may incorporate a handle operated pinion which engages with a rack (not shown) to move the drive member 75 to and fro in the directions of the arrows A. The drive member 75 has an elongated aperture 77 formed therein through which an elongated swivel head 81 of the turnbuckle device 79 may pass. The turnbuckle device 79 projects upwardly from a flat surface of a step 84 provided in an adjustable portion 85 of the shoot bolt 71. An upstanding pillar 80 of the turnbuckle device 79 is sufficiently small to fit with a close fit within the aperture 77 and is such as pivotally to support the swivel head 81. To assemble the drive member 75 with the adjustable portion of the shoot bolt 71, the swivel head 81 is first swivelled through 90° relative to its illustrated position, thus allowing the swivel head 81 to pass through the aperture 77. A recess 83 of a depth substantially corresponding to the depth of the swivel head 81 is formed in the top face of the drive member 75, and so long as the height of the pillar 80 of the turnbuckle device 79 corresponds to the thickness of the drive member 75 (less the depth of the recess 83) , and the diameter of the recess 83 is slightly greater than the maximum length of the swivel head 81, this will allow the swivel head 81 then to be turned through 90° to its illustrated position, thus holding the drive member 75 and adjustable portion 85 of the shoot bolt 71 in assembled condition.

The adjustable portion 85 of the shoot bolt 71 may be adjusted relative to the remainder of the shoot bolt 71 in known manner, e.g. by providing cooperating ratchet teeth, such as the teeth 87 on engaging faces of the two parts, and securing the two parts together in a selected position.

It will thus be appreciated that by using a turnbuckle of the construction described above to join the drive member 75 to the shoot bolt 71, it is a simple matter to assemble the two parts together and different length shoot bolts can be fitted to common operating mechanisms for different size window and door sashes.

It will of course be understood that the present invention has been described above purely by way of example, and modifications of detail can be made within the scope of the invention.

Claims

1. A latching mechanism for latching a panel such as a door or window sash in a closed position in a frame therefor, the mechanism comprising a shoot bolt adapted to be mounted on the sash and moveable between a withdrawn position and an extended latching position, a latch plate adapted to be secured to the frame for the panel and having an apertured keep portion for receiving a free end of the shoot bolt, and means adapted to be mounted on the sash defining a slot across which the free end of the shoot bolt passes when the latter is moved between its withdrawn and latching positions, said slot being arranged, when the panel is in a closed position, to receive the apertured keep portion with the aperture therein in line with the shoot bolt, and a further aperture in the means defining the slot to receive the free end of the shoot bolt when the latter in its extended locking position.

2. A latching mechanism according to claim 1 wherein the latch plate is L-shaped with one arm of the L having apertures therein for connecting the latch plate to the frame, and the other arm of the L providing said apertured keep portion.

3. A latching mechanism according to claim 1 or 2 wherein the means defining the slot comprises a security plate secured to an edge face of the panel and having an end portion in which said further aperture is formed, when end portion together with said end face of said panel defines said slot to receive the keep portion of the latch plate.

4. A latching mechanism according to claim 1, 2 or 3 which, with the exception of the latch plate is adapted to be mounted on face edge portions of the frame of the door or window sash, with the shoot bolt sliding longitudinally in a groove formed in one face and its free end portion sliding within a corner guide located in the grooves at the corner of the sash frame.

5. A latching mechanism according to claim 4 wherein the corner guide engages within the grooves with a snap-fit.

6. A latching mechanism for a panel such as a door or window sash for latching the sash in a closed position in a frame therefor, the latching mechanism comprising a shoot bolt adapted to be mounted for sliding movement in an edge face of the panel and a secondary latching member adapted to be mounted on the frame for the panel and to be actuated by movement of the shoot bolt to a latching position, the secondary latching member being moveable between a withdrawn position and a latching position in which a locking nose thereon engages in a recess provided in the panel.

7. A latching mechanism according to claim 6 wherein the shoot bolt is adapted for mounting in a groove formed in an edge face of a frame member of the sash, and with its end portion passing through at least one guide aperture on the corner of the sash frame.

8. A latching mechanism according to claim 6 or 7 including a corner reinforcement having two aligned apertures providing said guide aperture for the shoot bolt.

9. A latch mechanism according to claim 6, 7 or 8 wherein the secondary latching member is in the form of a bell crank lever, pivotally supported in a housing adapted to be mounted on the frame for the panel, the bell crank lever being supported on a pivot pin in the housing and being biassed to a withdrawn non-latching position by a spring and moveable by the shoot bolt when the latter is moved to an extended latching position engaging a first arm of the bell crank lever to move it against its spring bias from its withdrawn position to a latching position in which a second arm of the bell crank lever is moved to a latching position such that a locking nose thereon engages with the recess in the panel.

10. A locking mechanism according to claim 9 wherein the recess in the panel is provided by a groove in an end face of a frame member of the panel.

11. A latching mechanism according to claim 9 or 10 wherein the housing is sufficiently slim to be mounted on the face of the frame for the panel facing the panel, in an air gap between the panel and frame therefor, so that there is no need to form holes in the frame to receive the shoot bolt.

12. A latching mechanism according to claim 9, 10 or 11 wherein the throw of the nose of the second arm of the bolt crank lever is greater than the throw of the shoot bolt.

13. A latching mechanism for latching a panel in a closed position in a frame therefor, the mechanism comprising a shoot bolt and an operating mechanism therefor, wherein an end portion of the shoot bolt is connectable to a drive member of the locking mechanism by a turnbuckle device.

14. A latching mechanism according to claim 13 wherein the turnbuckle device comprises an elongated aperture in one of the shoot bolt and drive member and a turnbuckle on the other of the shoot bolt and drive member, the turnbuckle having a swivelling head designed to pass with a close fit through the elongated aperture when in a particular orientation but when swivelled to any other orientation, not to pass through said elongated aperture.

15. A latching mechanism according to claim 14 wherein a circular recess generally concentric with the elongated aperture is provided in a face of whichever of the shoot bolt and drive member the aperture is formed, the recess having a depth at least equal to the depth of the swivelling head so that when the head has been swivelled to an orientation in which it will not pass through the elongated aperture, its upper face is not proud of the upper face of whichever of the shoot bolt and drive member the aperture is formed within.

16. A latching mechanism according to claim 14 or 15 wherein the aperture is formed within the drive member and the turnbuckle is formed on an end portion of the shoot bolt, which end portion is stepped to receive an end portion of the drive member within which the aperture and recess are formed, the stepped portion having the turnbuckle formed thereon.

17. A latching mechanism according to any one of claims 14 to 16 wherein the shoot bolt is adjustably connected to the remainder of the shoot bolt so that the length of the shoot bolt can be adjusted.

18. A latching mechanism substantially as hereinbefore described with reference to Figures 1 to 5 of the accompanying drawings.

19. A latching mechanism substantially as hereinbefore described with reference to Figures 2 to 4 of the accompanying drawings.

20. A latching mechanism substantially as hereinbefore described with reference to Figure 5 of the accompanying drawings .

21. A panel and frame provided with a latching mechanism as claimed in any one of claims 1 to 5 or 21.

22. A panel and frame provided with a latching mechanism as claimed in any one of claims 6 to 12 or 22.

23. A panel and frame provided with a latching mechanism as claimed in any one of claims 13 to 20 or 23.