GB2199608A - Shutters - Google Patents

Abstract

A shutter comprising elongate pivotable slats (12) has a locking mechanism comprising a plunger (16) mounted in the hollow interior of one of the slats. The plunger can extend from one end into a locating aperture (20), where it is held by a bolt (22) which projects into the opposite end of the slat; a key-operated lock (24) being provided for extending and retracting the bolt. The end of the plunger has an oblique face (18) to cam the plunger back into its sat. <IMAGE>

Description

SLATTED SHUTTERS This invention concerns a locking mechanism for a slatted shutter.

The problem of making provision for the locking of sliding shutters in their closed positions is one which has been wrestled with over many years.

Traditionally, for example in the tambour fronts of roll-top desks and like cabinets, the exposed endmost slat of the shutter has been constructed so as to be more robust than the rest of the slats of the shutter, so that a key-operated lock may be incorporated in it, operation of the key when the shutter is closed extending a tongue or bolt of the lock, so as to project out of the endmost slat and engage into a registering keeper-protected hole in a complementary fixed part of the cabinet. Usually, the lock is disposed approximately midway along the length of the endmost slat, so when operative it serves only to prevent prising up of the middle of the shutter, but does not effect any reliable retention of the longitudinal edges of the shutter.

The incorporation of locks in the endmost slats of so-called "vertical" shutters (which are guided by their edges in horizontal guides for horizontal sliding movement) is not easy to achieve in a satisfactory and practical way. It is, of course, possible to incorporate a lock centrally in the endmost slat of the shutter in a manner similar to that above described, for example, for roll-top desks and the like, but provision for a tongue or bolt to project and engage with a stationary part of the structure is not at all easy. Even if this can be achieved, it similarly anchors only a short portion of the endmost slat relative to the adjacent structure and this part is, of course, weakened by the need to make space in it to accommodate the lock, openings for a key and the projecting tongue or bolt.

According to the invention, there is provided a slatted shutter comprisng a series of elongate slats linked together edge to edge to be pivotable relative to each other, a locking mechanism for the shutter comprising elongate plunger means carried by at least one of the slats and extending parallel to that slat, the plunger means being displaceable to project beyond at least one end of said slat to extend into a locating opening, and a lock operable to prevent the return of said plunger means from its extended position in said opening, whereby to lock the shutter in position.

The arrangement may be such that the lock is embodied in or carried by the said at least one slat and the plunger means is in two parts so that operation thereof causes one part to protrude at each end of the slat, for instance into respective locating apertures, to lock the shutter.

A particularly simple construction is achieved, however, if the lock is provided at the opposite side of the shutter to that on which the locating opening is placed, the arrangement being such that operation of the lock extends a tongue or bolt to extend the plunger means into the locating opening at the other end of the slat, or at least preventing the return of the plunger means from that extended position.

Thus, in a more particular form of the invention, there is provided a slatted shutter comprising a series of elongate slats linked together edge to edge to be pivotable relative to each other, the series of slats being guided in a pair of opposed, parallel channel-section guides, at least one of the slats of the shutter being hollow and accommodating an elongate plunger means of a locking mechanism for the shutter, a manually operable lock being fixed on or adjacent one of said guides and comprising a bolt member that can be extended to project into the hollow interior of said at least one slat, the projection of the bolt member into said slat causing the extension of said plunger means from the opposite end of said slat into a locating opening on the other of said guides, or at least preventing the retraction of said plunger means from said aperture, whereby to lock the shutter in position.

In a horizontal shutter (i.e. a shutter wherein the slats are horizontal and the opening and closing movement of the shutter may include a vertical component) the arrangement can be such that the hollow slat accommodates plunger means comprising a single plunger element which is resiliently biased towards an inoperative position, operation of the lock displacing the bolt or tongue of the lock into the adjacent end of the hollow slat to displace the plunger element so that it protrudes at the other end of the slat.

In a vertical shutter, the lock may be disposed below the lower channel in which the shutter is guided, or above the upper channel. Where the lock is provided below the lower channel guide it may have, for example, a bolt or tongue on which rests the lower end.of the plunger means, in the form of a single plunger element, the shape and disposition being such that in the unlocked condition the lower end of that plunger element is aligned to slide along the lower channel guide while in the locked condition it projects downwards below the level of the lower guide to be prevented from moving therealong. This may be achieved simply by gravity, or by biasing, e.g. spring-loading, the plunger.

If the lock is provided above the upper channel guide, in a particularly simple embodiment the lower end of a vertically-slidable element of the plunger means extends below the level of the lower channel guide and to be held there in the locked condition by the bolt or tongue of the lock projecting down under gravity into the upper end of the slat, opening sliding movement of the shutter being rendered possible, upon unlocking of the lock to withdraw the bolt or tongue, by reason of an inclined surface of the bottom end of the plunger element riding up a complementary surface of the lower channel guide to enable the lower end of the plunger element to slide along the guide.

The invention will be described further, by way of example, with reference to a preferred embodiment thereof as applied to a vertical (i.e.

side-opening) shutter, as illustrated in the accompanying schematic drawing which is a partial front view of the shutter, illustrating also the displacement of the plunger means of the shutter from its locking position.

Fig. 1 shows a vertical shutter 2 provided as a closure for, e.g. the front opening of a cabinet (not shown), having the opening fitted with top and bottom I-section extruded members 4,6, their central webs horizontal, so as to provide top and bottom guide channels 8,10 facing one another respectively from above and below, these channels, beyond one end of the opening, curving inwards alongside a sidewall of the cabinet. The shutter 2 comprises a series of side-by-side vertical slats 12, e.g. of extruded plastics material connected together pivotally at their edges, for example each slat (except the endmost) having in known manner a circular bead along one longitudinal edge and a slotted socket along the other, the bead of one slat fitting into the socket of an adjoining slat so that the slats are hingedly connected together.

Each slat is so connected to each of its neighbours, of course, with the exception of the two endmost slats each of which is connected to only one adjacent slat.

The assembly of slats is located by the upper and lower ends of the slats engaging in the top and bottom guide channels 8,10, the overall length of the assembly being such that a rear end slat is always disposed in those parts of the guide channels which curve inwards of the cabinet even when the cabinet opening is fully closed by the shutter being drawn fully across it to bring the opposite front end slat into abutment against the jamb of the opening.

Each of the slats has a hollow cross-section, preferably so as to provide, between its bead and socket edges a box-section body, substantially rectangular in cross-section, and the front end slat 12a accommodates, in its body, an elongate plunger 16 in the form of a rectangular-section bar or strip, e.g. of a plastics material such as moulded or extruded nylon or polypropylene, of length almost equal to the length of the slat and having an angled or bevelled face 18 at its lower end.

In the closed position of the shutter, this lower end comes into register with an opening 20 in the bottom web of the lower channel 10 and thus drops below the channel to rest in the lower part of the I section member 6.

Correspondingly, in the closed position of the shutter, the top of the front end slat 12a registers with a bolt or plunger 22 of a key-operated lock 24 set into the structure of the cabinet above the top I-section 4, the bolt being extendable, by operating the lock mechanism, through an opening 26 in the top section web into the hollow body of the front slat to bear upon the plunger so as to hold it below the level of the bottom guide channel. As a result, the shutter is firmly locked at both the top and bottom of the exposed front slat and cannot be opened whilst the bolt 22 is locked down. Upon unlocking, by turning the key in the lock, the bolt is withdrawn out of the top of the front slat.The plunger 16 is then free to move and, when the shutter is urged in the opening direction, the inclined surface 18 of the bottom of the plunger rides up the edge of the bottom web opening 20 with a camming action to bring it to the level of the top surface of the web of the bottom channel 10, along which it can slide.

When the shutter is re.turned to the closed condition, the plunger falls, under gravity, back to the locking position and turning of the key to extend the bolt of the lock again secures the shutter again.

It will be seen that this embodiment of the invention is simple, and involves few components, with very little risk of malfunction. By incorporating the plunger within a hollow slat, and similarly having the lock bolt project into the hollow interior of the slat, the locking mechanism reinforces that slat.

Many variations are possible within the scope of the invention. For example, it is not necessary to rely on gravity, and the.plunger could be springloaded to its extended position. If desired, the lock may be provided below the bottom guide channel for its bolt or tongue to engage the bottom end of the plunger to extend the plunger through the top of its slat for locking the shutter. In this instance, the tongue or bolt may be of convex configuration to make it easier for the plunger to ride over it when it is retracted, and if desired the plunger may be spring-loaded towards its inoperative position.

The invention is also applicable to horizontal shutters, (i.e. shutters in which the slats are horizontal) e.g. with the plunger spring-loaded to its non-extended position from which it is displaced by the bolt or tongue of the lock to secure the shutter closed. Embodiments are also possible where the lock is incorporated within the associated slat, in which case plunger means in the slat may comprise two parts which are extended, respectively, from opposite ends of the slat to lock the shutter.

In the illustrated example all of the slats are of the same configuration; of course, the shutter may be composed of a plurality of slats of which only one is of hollow cross-section and accommodates the plunger means. Moreover, the locking slat need not be the endmost slat of the shutter but may be any selected one of the slats, and of course the arrangement may be such that more than one of the slats is so furnished. The locking plunger may, of course, cooperate with an arresting surface provided by the cabinet structure and/or one or both of the guide channels, as may be desired or practical.

Claims (11)

1. A slatted shutter comprising a series of elongate slats linked together edge to edge to be pivotable relative to each other, a locking mechanism for the shutter comprising elongate plunger means carried by at least one of the slats and extending parallel to that slat, the plunger means being displaceable to project beyond at least one end of said slat to extend into a locating opening, and a lock operable to prevent the return of said plunger means from its extended position in said opening, whereby to lock the shutter in position.

2. A shutter according to claim 1 wherein said slat carrying the plunger means is hollow and the plunger means is slidably mounted in the interior of said slat.

3. A shutter according to claim 1 or claim 2 wherein the plunger means comprises a member of substantially the same length as its associated slat.

4. A shutter according to any one of the preceding claims wherein the lock is mounted in a fixed position beyond one end of the associated slat and comprises a locking element that can be extended to project into the path of the plunger means to block its return from the extended position.

5. A shutter according to any one of claims 1 to 3 wherein the lock is carried on said slat and the plunger means comprises respective members that are extendable jointly and in opposite directions from the opposite ends of the slat to seat in respective locating apertures.

6. A shutter according to any one of the preceding claims wherein the plunger means is biased away from its extended position to be displaced by the lock against said bias to lock the shutter in position.

7. A shutter according to any one of the preceding claims wherein the shutter is arranged to be mounted with the plunger means downwardly extendable under its own weight.

8. A shutter according to any one of the preceding claims wherein the or at least one portion of the shutter means arranged to be extended has an oblique end face providing a camming surface for assisting the return of said element to a non-extended position when the shutter is opened.

9. A slatted shutter comprising a series of elongate slats linked together edge to edge to be pivotable relative to each other, the series of slats being guided in a pair of opposed, parallel channelsection guides, at least one of the slats of the shutter being hollow and accommodating an elongate plunger means of a locking mechanism for the shutter, a manually operable lock being fixed on or adjacent one of said guides and comprising a bolt member that can be extended to project into the hollow interior of said at least one slat, the projection of the bolt member into said slat causing the extension of said plunger means from the opposite end of said slat into a locating opening on the other of said guides, or at least preventing the retraction of said plunger means from said aperture, whereby to lock the shutter in position.

10. A slatted shutter constructed and arranged for use substantially as described herein with reference to the accompanying drawings.

11. A cabinet provided with a slatted shutter according to any one of the preceding claims.