Sash Window Restrictor

FIELD OF THE INVENTION

This invention relates to a device for limiting or restricting the extent of opening of a sliding sash window. This device will be referred to herein as a sash window restrictor.

There is a requirement to restrict the extent to which a sash window can be opened, partly to prevent children opening a window beyond a certain distance so that they cannot fall out through the window, and partly form an anti-theft point of view, to prevent the window being opened from the outside.

However any such restrictor needs to be capable of being overridden when the window is to be fully opened by an adult, from the inside.

It is an aim of the present invention to overcome at least one problem associated with the prior art whether referred to herein or otherwise.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention, there is provided a sash restrictor comprising a housing, a tab which is retractable into the housing and extendable from the housing, and a mechanism acting between the tab and the housing which allows the tab to be pressed into the housing and which holds the tab in the housing for a predetermined period of time before the tab is released to allow the tab to extend.

Preferably the mechanism comprises a timing mechanism to provide a predetermined delay prior to releasing the tab and allowing the tab to extend.

The housing will preferably be set into a vertical frame member of one sash (normally the upper, outer sash) of a window, at a position, say, 10 cm above the

top rail of the lower sash when the windows are closed. When the tab is retracted, it will lie substantially flush with the frame member, but when extended will project from the frame member sufficiently far to prevent the lower sash from passing. With the tab extended, the lower sash can be lifted until it reaches the tab but no further, so that a 10cm gap will be opened at the bottom of the window.

When the window is to be opened fully, the tab will be pressed in and the bottom sash will be slid up, past the retracted tab, before the tab is able to extend.

There may be restrictor devices on both sides of the window, or just on one side. If there are restrictor devices on both sides, two separate operations will be required before the window can open, and this can provide an added security measure to make it more difficult for a window to be opened by a child.

Where there is a restrictor device on only one side, the device may have a second user-actuated feature so that the tab can only be pressed in once the second feature has been actuated. Again, this can provide an added security measure to make it more difficult for a window to be opened by a child.

Many different mechanisms can be used to hold the tab in the housing for a period of time. Generally the tab will be extended from the housing by a spring, and when pressed back in, ie retracted into the housing, the spring will be tensioned. It may however be possible to design a mechanism where gravity, or another method, is used to extend the tab from the housing

In one form, the mechanism will not lock the tab in its retracted position, but will damp the restoring force of the spring, so that the spring is only able to slowly extend the tab. However in other embodiments, the tab may lock into the housing and a separate trigger can be operated, for example by movement of the lower sash, to release the tab.

The tab may be pivoted in the housing such that one end of the tab will project

from the housing, in the extended position. Alternatively, the tab may move linearly into and out of the housing. Part of the edge of the tab which, in use, will be facing the lower sash may have an inclined face to allow the sash to pass the tab, pushing it in to the housing as it does so, to allow the sash to pass even if the tab is not completely retracted. However such inclined face should only be at the outermost part of the tab edge, as the main part of that tab edge should be substantially at right angles to the direction of movement of the lower sash, so as to prevent the sash passing when the tab is fully extended.

The mechanism between the tab and the housing preferably incorporates a spring and energy is stored in the spring when the tab is pushed into the housing. The mechanism may lock the tab in the retracted position, and a trigger may be activated by the passing of the lowers sash to release the lock and to allow the tab to be extended by the spring. While the lower sash lies in front of the device, the tab can only extend into contact with the lower sash frame, but once the lower sash is returned to its closed position, the tab will spring fully out to prevent reopening of the window without the tab being pushed in again.

In another embodiment, the tab can be linearly movable and can be controlled by a push-push mechanism where the first push locks the tab in its retracted position in the housing and a subsequent push releases the tab, allowing it to extend. The second push can be provided by the lower sash as it passes the device.

Instead of a lock, the stored spring force may be released only slowly, for example under the control of some form of damping system. In this embodiment, the tab will start to extend as soon as the force pushing it into the retracted position is released. However the speed at which the tab extends will be slow enough to allow the lower sash to be moved past the device before very much extension has taken place.

According to a second aspect of the present invention, there is provided an assembly comprising a sash and a sash restrictor comprising a housing, a tab

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which is retractable into the housing and extendable from the housing, and a mechanism acting between the tab and the housing which allows the tab to be pressed into the housing and which holds the tab in the housing for a predetermined period of time before the tab is released to allow the tab to extend.

According to a third aspect of the present invention, there is provided a kit for assembly into a sash restrictor comprising a housing, a tab which is retractable into the housing and extendable from the housing, and a mechanism acting between the tab and the housing which allows the tab to be pressed into the housing and which holds the tab in the housing for a predetermined period of time before the tab is released to allow the tab to extend.

According to a fourth aspect of the present invention, there is provided a method of restricting movement of a sash comprising mounting a sash restrictor adjacent to a sash wherein the sash restrictor comprises a housing, a tab which is retractable into the housing and extendable from the housing, and a mechanism acting between the tab and the housing which allows the tab to be pressed into the housing and which holds the tab in the housing for a predetermined period of time before the tab is released to allow the tab to extend.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a side view through part of an upper and a lower sash, with a sash limiter device in accordance with the invention fitted in the upper sash;

Figure 2 is a schematic representation of the sash limiter device from Figure 1 , with the tab extended;

Figure 3 corresponds to Figure 2 but shows the tab retracted;

Figure 4 is a cross-sectional view through a second type of sash limiter device in accordance with the invention;

Figure 5 is a perspective view of the device of Figure 4;

Figure 6 is a perspective view of a preferred embodiment of a sash restrictor;

Figure 7 is a front view of a preferred embodiment of a sash restrictor;

Figure 8 is a side view of a preferred embodiment of a sash restrictor;

Figure 9 is a rear view of a preferred embodiment of a sash restrictor;

Figure 10 is a bottom view of a preferred embodiment of a sash restrictor;

Figure 11 is another side view of a preferred embodiment of a sash restrictor;

Figure 12 is a top view of a preferred embodiment of a sash restrictor;

Figure 13 is a partially cut away view of a first side of a preferred embodiment of a sash restrictor with the tab in a retracted position;

Figure 14 is a partially cut away view of a first side of a preferred embodiment of a sash restrictor with the tab in an extended position;

Figure 15 is a partially cut away view of a second side of a preferred embodiment of a sash restrictor with the tab in a retracted position;

Figure 16 is a partially cut away view of a second side of a preferred embodiment of a sash restrictor with the tab in an extended position;

Figure 17 is a perspective view of a clutch mechanism of a preferred embodiment of a sash restrictor,

Figure 18 is a side perspective view of an inner sprocket and a clutch member of a clutch mechanism of a preferred embodiment of a sash restrictor;

Figure 19 is a front view of a clutch mechanism of a preferred embodiment of a sash restrictor; and

Figure 20 is a front view of an inner sprocket and a clutch member of a clutch mechanism of a preferred embodiment of a sash restrictor.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Figure 1 shows, in side view, an upper sash 10 and a lower sash 12. The sashes are shown in the position which they would take up when the window is closed, and in this position, the horizontal meeting rails of the two sashes overlap at 14. Weather seals 16, 18 are shown on the respective sashes to provide a seal when the window is closed.

The upper sash includes a sash limiter device at 20. This device has a housing 22 which is recessed into the sash frame 10, and a tab 24 which is movable between an extended, projecting position as shown, and a retracted position where it is housed substantially completely in the housing 22.

In the extended position of the tab 24 as shown in Figure 1 , the lower sash 12 can be raised relative to the upper sash 10, until the upper face of the lower sash comes into contact with the tab 24. Further lifting of the lower sash 12 is then prevented. However when it is desired to open the window completely, and to raise the lower sash 12 past the limiter device 20, the tab 24 can be pressed back and retracted into the housing 22 to allow the lower sash to pass the device.

It is desirable that the retracted tab should automatically extend itself out of the housing 20, once the leading edge of the lower sash 12 has moved passed. Thus, once the leading edge of the lower sash 12 has passed the device, the tab will extend, either gradually or quickly, and as the lower sash is lifted further, the tab will bear against a surface of the lower sash frame. In this way, once the lower sash is lowered again and the window is closed, the tab will automatically move to its extended position without any user intervention being required.

The tab will preferably be spring-loaded and can be pressed into the housing against spring pressure, with the spring being released to re-extend the tab once the lower sash has passed the device. In some embodiments, a secondary lock may lock the tab in the open position, and require release before the tab can be pressed in. It may be necessary to hold a button or the like release mechanism whilst at the same time pressing in the tab.

The tab itself may take up a number of different configurations. In Figures 1 , 2 and 3 the tab is generally triangular and is pivoted at 26 in the housing. The tab may however slide in the housing between its extended and retracted positions. The tab has a tapered edge at 24a, so that the lower sash can pass over the tab, even though the tab might not be fully retracted.

Figure 2 shows one example of a mechanism which can be used to control extension and retraction of the tab 24. The extension of the tab, into the position shown in Figure 2, is limited by engagement between an ear 28 on the tab and a shoulder 30 in the housing.

When the tab is pushed in, a rack 32 which is integral with the tab engages with a first, inner sprocket 34 and rotates that sprocket in a clockwise direction. This rotation entrains an outer sprocket 36. The outer sprocket 36 engages with a second sprocket 38, and this second sprocket includes a coil spring 39 which is wound up as the tab is pushed in and the second sprocket rotates. A third

sprocket 40 meshes with the sprocket 38 and has a release cam 42 at one point around its circumference, and an escapement 44. The housing also contains a retaining plate 46 which is vertically slidable in the housing under the influence of a spring 48.

As can be seen from Figure 3, when the tab is fully retracted, the end of the rack 32 engages with a detent on the bottom of the plate 46, and in this position the tab 24 is held in the retracted position. However the stored energy in the spring 39 continues to drive the sprocket 40 and its associated cam 42 in a clockwise direction. The extent to which the rotation can take place is limited by the rocking movement of the escapement 44, but the cam 42 will contact a lug 50 on the plate 46, to release the tab which will then be driven into its extended position by the stored energy in the spring 39.

It will be noted that the first sprocket 34 has a clutch mechanism within the outer sprocket 36, and this ensures that rotation of the sprocket 34 in a clockwise direction rotates the outer sprocket 36, but when the inner sprocket rotates in the opposite direction, the sprocket 36 is not entrained. In the retracted position shown in Figure 3, the inner sprocket 34 can rotate freely within a part circular cutout 52 in the tab.

As explained above, the operation of the sash window restrictor may comprise a single action although as mentioned above the opening of the window may require a double action or dual action restricting mechanism. In order to provide a dual action sash window restrictor means, the sash window may be provided with two separate single action sash window restrictors. Alternatively, the sash window restrictor is provided with a dual action requirement. For example, the sash window restrictor may be provided with a locking button that must be moved out of engagement with the tab to allow the tab to initially be pressed into the housing. In particular, the button is slid out of engagement with the tab to enable the tab to be pressed in which thereby provides a dual action requirement. The locking button is also arranged to automatically reset.

Figures 4 and 5 show another embodiment where the tab 124 slides linearly into and out of a housing 122. The mechanism of this device works on a "push-push" principle, i.e. when the tab 124 is pushed in, it locks into a retracted position and if it is pushed again, the lock is released and a spring 139 extends the tab. In this case, the tab 124 has a tapered end, and the dimensions and stroke of the tab 124 will be such that, in the retracted position, the tip of the tab extends from the housing 122, with the tapered face facing the direction from which the lower sash will approach. When the lower sash contacts the tapered face, it will press the tab inwards to allow the window to pass, but also at the same time the lower sash will provide the second "push" to activate the release of the tab which will then be biased by the spring 139 against the face of the sash frame, as the sash moves past the tab. When the sash is moved back to its closed position, and passes the device 120, the tab 124 will be free to move to its fully extended position where it blocks movement of the sash passed the tab.

To enable the window to be opened, the user must push the tab in so that it locks in the retracted position.

The devices described are just two examples of sash window restrictors. It is important that the restrictor, once retracted to allow the window to be fully opened, automatically resets itself so that when the window is closed, the tab of the restrictor automatically moves into its window restricting position.

The tab can be any shape which can prevent movement of one sash past the other, and the term "tab" is not intended to limit the possible forms of this component.

There may be sash restricting devices of this type on one side of a window, or on both sides of the window. If there are safety requirements requiring at least two manual operations before a window can be fully opened, these requirements can be met by fitting a device as described here on both sides of the window.

Alternatively (or additionally) the or each device can be provided with a secondary lock which locks the tab in the extended position and requires manual operation to release that lock before the tab can be pushed in.

The preferred embodiment will now be described with particular reference to Figure 13 to Figure 20 which shows a sash restrictor 220. When the tab is pushed in, a rack 232 which is integral with the tab 224 and provided on an arm 227 of the tab 224 engages with a first inner sprocket 234 and rotates the first inner sprocket 234 in a clockwise direction (when viewed from the second side, as shown in Figure 16). This rotation entrains a first, outer sprocket 236 through a clutch mechanism 235. The outer sprocket 236 engages with an inner sprocket of an intermediary sprocket 237. An outer sprocket of the intermediary sprocket 237 engages a first side sprocket of the second sprocket 238. This second sprocket 238 includes a coil spring 239 located between a first side sprocket and a second side sprocket which is wound up as the tab 234 is pushed in and the second sprocket 238 rotates. The first side sprocket and the second side sprocket are connected through a clutch mechanism such that as the tab is being pushed inwardly the first side sprocket does not rotate the second side sprocket. This prevents the subsequent sprockets (the first gear sprocket 239, the second gear sprocket 241 and the third sprocket 240) from being rotated whilst the tab 224 is being pushed inwardly.

When the tab 224 is released, a third sprocket 240 is driven by the second sprocket 238 through the second side sprocket driving an inner sprocket of a first gear sprocket 239. An outer sprocket of the first gear sprocket 239 drives an inner sprocket of a second gear sprocket 241. Finally, an outer sprocket of the second gear sprocket 241 drives an inner sprocket of the third sprocket 240 and an outer sprocket of the third sprocket 240 engages with an escapement 244. This arrangement thereby provides a calibrated gearing mechanism to provide a predetermined time period prior to releasing the tab 224 from a retracted and latched position.

The housing 222 contains a retaining member 246 which is rotatable in the housing 222 under the influence of a spring 248. The retaining member 246 is actuated by actuation means comprising an actuation arm 270 (a rocking arm) which is pivotally mounted in the housing on a pivot member 272. The actuation arm 270 comprises a first lug 274 located towards a first end 275 of the actuation arm 270 and a second lug 276 located towards a second end 277 of the actuation arm 270. The first lug is engaged in a slot 280 defined in an actuation sprocket 278. The actuation sprocket is rotated as the rack 232 is pushed inwardly through the rotation of the inner sprocket of the intermediary sprocket 237 which engages with the actuation sprocket.

The slot 280 comprises an arcuate slot. As the rack moves inwardly, the actuation sprocket 278 rotates and the first lug 274 moves relatively around the slot 280 (although the first lug 274 effectively remains initially stationary) towards a first end 281 of the slot 280. The arm 227 of the tab 224 includes a shaped surface including an abutment portion 249 and a recess 250. As the tab 224 is pushed inwardly the abutment portion 249 contacts the retaining member 246 rotates the retaining member 246. The abutment portion moves passed the retaining member 246 such that the retaining member 246 locates in the recess 250. The second lug 276 of the actuating arm 270 holds the retaining member 246 and prevents rotation of the retaining member which would allow the tab 224 to extend. This effectively temporarily locks the tab 224 in a retracted position by preventing the retaining member from rotating which would allow the retaining member 246 to move out of the recess.

When the tab 224 is fully retracted, a recess 250 defined on one side of the tab 224 adjacent to the rack 232 engages with a latching member 246, and in this position the tab 224 is held in the retracted position. Once the tab is released in the retracted position, the stored energy in the spring 239 drives the second sprocket 238 and thereby the third sprocket 240 through the first and second gear sprockets 239, 241. The actuation sprocket 278 is also driven under the control

of the escapement 244 and this slowly moves the first lug 275 relative to the slot 280.

The slot 280 is neither concentric nor circular and the radius of the slot 280 effectively gradually increases in a section at one end. When the lug travels around this section in which the radius gradually increases, the arm 270 pivots such that the first end 275 of the arm moves downwardly and the second end 277 moves upwardly. This thereby moves the second lug 276 upwardly and effectively releases the retaining member 246 which then rotates under the action of the spring 248. This enables the abutment portion to move passed the retaining member 246. This thereby initiates the movement of the tab 224 from the retracted position to the extended position under the action of the spring 260. This mechanism provides a time delay whereby the tab 224 is held in a fully retracted position prior to a release to the extended position.

The extent (or speed) to which the rotation can take place is limited by the rocking movement of the escapement 244, to release the tab 224 which will then be driven into its extended position by the stored energy in the spring 260.

It will be noted that the first sprocket 234 has a clutch mechanism 235 within the outer sprocket 236, and this ensures that rotation of the sprocket 234 in a first direction rotates the outer sprocket 236, but when the inner sprocket rotates in the opposite direction the outer sprocket 236 is not entrained.

Furthermore, a clutch mechanism and, in particular, a bump or dog clutch mechanism is located in a housing 233 of the first sprocket 234. A spring 293 acts on the dog clutch such that rotation of the inner sprocket 234 causes rotation of the outer sprocket 236. However, if the inner sprocket 234 tries to rotate the outer sprocket 236 when the outer sprocket 236 is otherwise prevented from rotating (for example, because the first lug 274 is at an end of the slot 280) then the outer sprocket moves axially along its spindle such that rotation of the inner sprocket 234 does not produce rotation of the outer sprocket 236. This protects the

mechanism from mechanical damage. The clutch mechanisms are shown in more detail in Figure 17 to Figure 20 and show the interactions between the inner sprocket 234, the outer sprocket 236 and the engaging clutch member 299. The mechanism further includes a spring member 293 and a spindle 295.

Furthermore, the sash window restrictor may be lockable such that a lock mechanism protects and restricts the use and operation of the sash window restrictor.

In particular, as mentioned above the sash window restrictor is provided with a locking button which engages the tab such that the button must be slid (or pressed) out of engagement with the tab to enable the tab to be pressed inwardly.

There may also be locking versions of each type based on the same assemblies one using a key and another using a press button and further version may use other suitable locking mechanisms. The press button version will automatically be set in the locked position and will have to have the button pressed to free the locking arm allowing it to be depressed and the sash to be opened. When the sash is closed the locking button will reset preventing the arm from being manually depressed. The key version will have to be manually unlocked with the key before the limiter can be used in the normal way and then locked with the key to make it secure.

The locking version includes a barrel type lock in which a rotatable spindle 300 comprises an axially mounted locking plate 302. As the spindle 300 is rotated, the locking plate 302 is moved into or out of the path of locking plate provided on an arm 304 of the tab 224. This may prevent the tab being pushed into the retracted position and/or from allowing the tab to move to a fully extended position once in the retracted position.

The present invention is primarily applicable to sash windows and limiting or restricting the movement of a first sash window relative to a second sash window.

However, the present invention can be used in other applications to prevent relative movement of a sash, for example the inset unit could be fitted into sliding patio doors to allow them to be opened a small distance while being secure.

The sash window restrictor may be mounted an any suitable part of the window or window frame including a window frame member, a sash member, a stile, a jamb etc.

If required, the assembly may include a bracket or abutment member which is arranged on the other part of the window assembly from the tab and provides a suitable placed abutment surface to abut with the tab to restrict the opening of the window.

The present invention is for use with all suitable sash windows, for example horizontal and vertical sliding sash windows.