GB2177452A - Mounting sliding bolt fastening - Google Patents

Abstract

The fastening has a casing 10 and a mushroom-headed bolt 20 movable normal to the door sliding direction to cooperate with a keyhole slot 52 in the door frame. The element 20 is removable, from the exterior of the casing, to allow the fastening to be inserted in a tubular door stile, secured adjacent an opening 22, and the bolt reattached. The opening 22 can be quite small so as not to weaken the structure. An interlock 34 may cooperate with the frame to prevent the bolt 20 assuming the latched position when the door is open and possible consequent damage to the frame by the bolt 20 when the door is closed. <IMAGE>

Description

SPECIFICATION Latch mechanism for a sliding door The invention relates to a latch mechanism for a sliding door, of the kind having a latch element projecting generally in the door-sliding direction and movable normal to this direction, generally in the plane of the door, to achieve latching engagement with a supporting structure such as a door frame.

Many current door constructions utilise assemblies of tubular frame members. Such frame members may be extrusions of metal, e.g.

aluminium alloy, or plastics, e.g. UPVC. To fit latch mechanisms, as generally known hitherto, to a stile member of such a door requires a large aperture to be cut in the stile member, which appreciably weakens it. It is the object of the present invention to provide a latch mechanism which permits a mode of installation enabling this disadvantage to be overcome or reduced.

The invention achieves this object by providing a latch mechanism which is able to be installed by being introduced into the end of a tubular stile member and being slidden lengthwise thereof to reach its installed position.

The invention provides therefore a latch mechanism for a sliding door comprising a casing having a latch element mounted for movement relative to the casing in a direction which, when the latch mechanism is in use, is normal to a doorsliding direction, and an operating mechanism operable to move said latch element between latched and unlatched positions, said latch element projecting from the casing substantially in the door: sliding direction and having a portion arranged such that it is capable of engaging, in said latched position when the door is closed, an abutment on a supporting structure, relative to which the door is slidable in use; the latch element being mounted so as to be releasably detachable exteriorly of the casing to permit the casing and its contents to be introduced, in use, into the interior of an elongate tubular door member from one end of the tube and to be positioned for securement adjacent an opening, in the tube wall, smallerthan said casing but large enough for said latch element and other operative elements of the mechanism to project therethrough, the latch element being reattached to the mechanism, for latching and unlatching the door.

Further, it is known to provide a latch mechanism for a sliding door such as is shown in our British Patent Application 2130287 where the latch element is spring biased to a latched position but which on contact with the supporting structure can move against the spring bias to an unlatched position. By this means damage by contact of the latch element with the frame due to the latter being held in a latched position, is avoided. A further feature of the present invention seeks to provide a latch mechanism in which the latch element is dead but which still avoids the damage set out above.

To achieve this, the latch mechanism may be provided with interlock means cooperable with said supporting structure when the door is closed and operable to prevent movement of the latch element to the latched position unless the door is closed, said interlock means being retractable within the casing for introduction of the casing and its contents into the interior of said door member.

The latch element may be operable by a slide member mounted for sliding movemerit in the casing and movable by a pivot member with which, in use, a handle is operatively connected. The slide member may be securable, by a key-operable device, against movement so as to prevent the latch element being moved from the latched position.

The latch element may be operable by a slide member movable by a key-operable device to move the latch element between latched and unlatched positions.

Espagnolette bars may be provided for securement of the door to the supporting structure at locations remote from the latch element. The espagnolette bars are preferably operable with the latch element.

The espagnolette bars may be mounted for movement in dependence upon movement of the slide member, and preferably are attached thereto.

The latch element is preferably releasably secured to the slide member by a threaded fastening, and may be provided with a lock nut whereby the amount by which the latch element projects from the casing may be adjustably chosen.

The latch element preferably comprises a mushroom-headed member, the head of which may be cooperably received, in use, in a keyhole aperture in the supporting structure.

Embodiments of the invention will now be described by way of example only, and with reference to the accompanying drawings, in which: Fig. 1 is a schematic view, shown partly broken away, of a latch mechanism according to the invention installed for use in a door assembly, but with a cover plate of its casing removed, Fig. 2 is a schematic view similar to that of Fig. 1 of a second latch mechanism of a simplified form according to the invention, and Fig. 3 is a front elevational view of a portion of a supporting structure with which the mechanism shown in Figs. 1 and 2 may cooperate.

Fig. 1 shows a latch mechanism in a latched position and comprising a casing shown generally as 10 in which is mounted, for sliding movement normal to a door-closing direction X, a slide member 12 having end portions 14 apertured for attachment to espagnolette bars (not shown). A central thickened portion shown generally as 16 of the slide member 12 is provided with a tapped bore which threadedly receives a shank portion 18 of a mushroom-headed bolt 20, the head end of which projects, in a door-closing direction, from the casing 10 through a slot shaped aperture 22 at a door edge portion of the casing. A lock nut 24 is threadedly engaged with the shank of the mushroom-headed bolt 20, abutting slide member 12 and by adjustment of the bolt and lock nut, the degree to which the mushroom head of the bolt 20 projects from the casing may be adjustably chosen.A crank member 26, having a square cross-section aperture 28 therein for receiving a conventional operating bar for use with handles (not shown) to operate the crank member 26, is pivotally mounted in the casing 10. The crank member 26 has a limb 30 which mounts at an end remote from the aperture 28 a circular projection 32 which is cooperable with a slot (shown in outline only) on one side of the slide member 12. Thus movement of the crank member 26 by a handle causes the slide member 12 to move relative to the casing 10.

An interlock member 34 is mounted for sliding movement in the direction X, and urged normally into a position where it projects from the casing by a spring 36. Member 34 and slide member 12 have, on sides where they abut each other, channel formations such that slide member 12 is permitted to move to the position shown in Fig. 1 (the latched position) only when the interlock member 34 is in the position shown in Fig. 1 i.e. with the member 34 retracted, by abutment with a door frame S forming part of a supporting structure. Operation of the mechanism will be described later. A locking member 38 is pivotally mounted in the casing and has an aperture 40 adapted, in use, to receive the operating bar of a cylinder lock.The locking member 38 has a limb 42 which, in the position shown in Fig. 1 abuts central region 16 of the slide member 12 and prevents it moving downwardly (from the latched position) as viewed in Fig. 1.

Movement of the locking member limb 42 in a clockwise sense as indicated by arrows Yto the position shown outlined in Fig.1, wherein the limb 42 underlies slide member 12, permits the latter to move downwardly under the influence of crank member 26. A spring 44 engages in one of two detents on the lock member 38 to provide a 'click' stop in the locked and unlocked positions. The mechanism is shown in position in the stile 46 of the door.

Operation of the latch mechanism shown in Fig. 1 will now be described. The mechanism is shown in Fig. 1 in the latched position, wherein the mushroom-headed bolt 20 is engaged behind a portion 50 of a keyhole shaped slot 52 (see Fig. 3) in a supporting structure S. In order to unlock the door, of which the stile 46 forms a part, the lock member 38 is first moved in a clockwise sense by the use of a key in the cylinder lock (not shown) to the position shown dotted in Fig. 1 whereupon operation of the crank member 26 in a clockwise sense as viewed in Fig. 1 byturning a handle (not shown) causes the slide member 12 to move downwardly and the mushroom-headed bolt 20 with it.The head of the mushroom-headed bolt 20 then aligns with the circular portion of the keyhole 52 whereupon the door may be slid in a direction opposite to direction X relative to the supporting structure S. As this happens, spring 36 urges member 34 outwardly to a position where a member 34 cooperates with slide member 12 and prevents the latter from being moved back into the latched position shown in Fig.

1. Thus, while the door is open, the mushroom headed bolt cannot assume the position shown in Fig. 1 wherein, if it were to be slammed against the supporting structure S, the mushroom-headed bolt 20 could cause damage in the region 50 of the keyhole aperture 52. Similarly, espagnolette bars (not shown) are not permitted to assume a latched position when the door is opened thereby preventing damage to the supporting structures, by espagnolette catches associated with the bars in known manner contacting the frame, if the door were to be closed with the espagnolette bars in this position.

The latch mechanism shown in Fig. 2 is a simpler version of that shown in Fig. 1 and the stile 46 and support structure S have been omitted for clarity.

The same reference numerals have been used for parts in Fig. 2 similar to those in Fig. 1. It will be noted that the slide member 12 has no provision for espagnolette bars and is operable by the limb 42 of locking member 38 in both directions. Limb 42 has a rounded projection 43 which cooperates with a rounded cam formation 45 on the slide member 12.

Thus, as the locking member 38 is moved in a clockwise sense as viewed in Fig. 2, the projection 43 abuts formation 45 and causes slide member 12 to move downwardly. From this position movement of the locking member 38 in an anticlockwise sense will cause projection 43 to abut central portion 16 of slide member 12 to move the slide member upwardly to the position shown in Fig. 2. Again, member 34 will prevent movement of slide member 12 to the position shown in Fig. 2 unless the door is closed, i.e. member 34 is pushed back into the position shown in Fig. 2 by its abutment with the door frame. In this embodiment, the mushroom headed bolt 20 is locked by a plastics locking insert, e.g. at 56 in the slide member 12, instead of a locknut.

It is to be noted that the mushroom headed bolt 20 and lock nut 24 are easily removable from the slide member 12, and that the member 34 is capable of complete retraction within the casing 10. With mushroom-headed bolt 20 removed and member 34 retracted, the casing and its contents can be introduced into the end of a tubular stile 46 and positioned adjacent opening 22 in a wall of the stile for securement by screws in an operative position, the screws tapping into threaded bores 54 (not shown in Fig. 1). Thus, the opening in the wall of the stile 46 may be much smaller than would allow the lock to be inserted therein through the wail, and thus the strength of the tubular stile will be not lessened to any significant degree as would be the case if the opening were much larger.

Various modifications may be made without departing from the scope of the invention. For example, the slide member 12 in the embodiment of Fig. 1 may be devoid of formations 14 for espagnolette bars, or the embodiment of Fig. 2 may have a slide member 12 which has formations for espagnolette bars.

It will be noted that if the handle (not shown) is to be used for moving the door between the open and closed positions then there may be a tendency in the absence of member 34, for the latch element to be moved to the latched position on closing of the door. Member 34 not only prevents this to avoid damage to the frame (supporting structure) as aforesaid but also provides a definite stop against movement of a handle relative to the door thus providing for a more secure grip by a user.

Claims (12)

1.A A latch mechanism for a sliding door comprising a casing having a latch element mounted for movement relative to the casing in a direction which, when the latch mechanism is in use, is normal to a door-sliding direction, and an operating mechanism operable to move said latch element between latched and unlatched positions, said latch element projecting from the casing substantially in the door-sliding direction and having a portion arranged such that it is capable of engaging, in said latched position when the door is closed, an abutment on a supporting structure relative to which the door is slidable in use; the latch element being mounted so as to be releasably detachable exteriorly of the casing to permit the casing and its contents to be introduced, in use, into the interior of an elongate tubular door member from one end of the tube and to be positioned for securement adjacent an opening, in the tube wall, smaller than said casing but large enough for said latch element and other operative elements of the mechanism to project therethrough, the latch element being reattached to the mechanism for latching and unlatching the door.

2. A latch mechanism as claimed in claim 1 in which there is provided interlock means cooperable with said supporting structure when the door is closed and operable to prevent movement of the latch element to the latched position unless the door is closed, said interlock means being retractable within the casing for introduction of the casing and its contents into the interior of said door member.

3. A latch mechanism as claimed in claim 1 or claim 2 in which said latch element is operable by a slide member mounted for sliding movement in the casing and movable by a pivot member with which, in use, a handle is operatively connected.

4. A latch mechanism as claimed in claim 3 in which said slide member is securable by a keyoperable device against movement so as to prevent the latch element being moved from the latched position.

5. A latch mechanism as claimed in claim 2 in which said latch element is operable by a slide member movable by a key-operable device to move the latch element between latched and unlatched positions.

6. A latch mechanism as claimed in any preceding claim in which there are provided espagnolette bars for securement of the door to the supporting structure at positions remote from the latch element.

7. A latch mechanism as claimed in claim 6 as appended to any of claims 3 to 5 in which the espagnolette bars are mounted for movement in dependence upon movement of the slide member.

8. A latch mechanism as claimed in any of claims 3 to 7 in which the latch element is releasably secured to the slide member by a threaded fastening.

9. A latch mechanism as claimed in claim 8 in which the latch element is provided with locking means whereby the amount by which the latch element projects from the casing may be adjustably chosen.

10. A latch mechanism as claimed in any preceding claim in which the latch element comprises a mushroom-headed member, the head of which may be cooperably received in a keyhole aperture in the supporting structure.

11. A latch mechanism substantially as hereinbefore described with reference to Figs. 1 and 3 of the accompanying drawings.

12. A latch mechanism substantially as hereinbefore described with reference to Figs. 2 and 3 of the accompanying drawings.