GB2236802A - A window stay - Google Patents

Abstract

In a window stay comprising a mounting plate 10 to fit on a frame and a mounting plate 11 to fit on a sash, the plates being connected by pivoted arms 12 and 13 to provide a four bar linkage, a further three-part articulated arm 17 is connected between the mounting plates 10 and 11 and is controlled by a releasable locking mechanism, on the mounting plate 11, to prevent the stay being opened beyond a predetermined distance. The locking mechanism may comprise a spring-loaded slider 35, 36, 38 having at one end a lug engageable in a slot 27 in one part 20 of the articulated arm 17 to prevent pivoting of part 20 relative to plate 11, the slider being releasable manually to allow pivoting of part 20 to the fully open position. The locking mechanism may be arranged to be controlled by a child-proof release device. <IMAGE>

Description

"Improvements in Window Stays" This invention relates to a window stay.

Window stays of the four bar or sliding shoe type are well known. A four bar stay basically comprises a pair of mounting plates which are coupled together by a pair of arms the ends of which are pivotally coupled to the respective mounting plates. Generally one arm is considerably shorter than the other arm. The sliding shoe stay generally comprises a mounting plate on which a shoe or carriage is slidingly engaged. One end of the other mounting plate is either directly or via a link attached to the shoe/carriage. The mounting plates are further coupled by an arm extending therebetween. With the four bar stay the stay is generally able to hold a window sash in an open position by controlled friction within the pivot bearings.With the sliding shoe/carriage type stay this friction can be obtained not only from the pivot bearings coupling the arm to the mounting plates but by friction between the shoe/carriage and the mounting plate.

The present invention is applicable to both categories of window stays though for ease of reference the invention will hereinafter be described in relation to a four bar stay.

It is a common requirement for a four bar friction stay, particularly when the stay is to be used in a projected side hung application, that the window sash should open to ninety degrees and provide sufficient room around the open sash for cleaning. This can be achieved but requires an overlap between the "hinge" end of the long arm and the "lockside" end of the short arm. This, however, results in the two friction bearings on the sash mounting plate being too close together to provide the degree of frictional control necessary to hold the sash secure in windy conditions.

It has been common to overcome this difficulty by installing a separate sliding control arm, which is visible on the inside of the windowsill, to hold the sash secure when fully open. An object of the present invention is thus to provide a. control device which is associated with the window stay and which thus can be concealed in the window cavity when the sash is in a closed position.

It is also a common requirement for windows that a safety stop be provided so as to prevent the sash from initially opening more than a specified distance generally no more than llomm. This provides for a sash to be left partially open for ventilation without any risk of a small child being able to open it further and thereby fall out of the window. Once again it is known for a sliding control arm to be mounted on the inside of the windowsill to provide this safety facility.

Such a sash limiting device also provides a high level of security in very windy conditions as in such conditions it is possible for the sash to be sucked open by the wind.

An object of the present invention is thus to provide a window stay incorporating a limiting arrangement which restricts the degree of opening of the stay but is able to be released so as to enable further opening of the window sash to take place.

Accordingly in one broad aspect there is provided a window stay comprising a first mounting plate coupled by coupling means to a second mounting plate, said coupling means including at least one arm which is respectively pivotally connected at or near each end to said first and second mounting plates, characterized in that an articulated arm is also coupled between said first and second mounting plates. Preferably there is provided releasable locking means which, unless released, prevents a part of said articulated arm being movable relative to the mounting plate to which said part is coupled.

In the following more detailed description of the invention reference will be made to the accompanying drawings in which: Figure 1 is an elevational view of the stay according to the invention when in its restricted open position, Figure 2 is an elevation view of the stay in its fully opened position, Figure 3 is a partial cross-sectional view of the lower portion of the sash mounting plate, Figure 4 is a sectioned view of a window sash supported in a window frame by the stay according to the present invention, Figure 5 is an elevational view of an alternative form of the locking arrangement, and Figure 6 is a plan view of the locking arrangement of the type shown in Figure 5.

The stay comprises a frame mounting plate 10 and a sash mounting plate 11 which are coupled together by arms 12 and 13. Arm 12 is in accordance with normal four bar stay geometry shorter in length. The ends of arms 12 and 13 are coupled to the frame mounting plate by pivot bearings 14. The arms are coupled at their other ends to the sash mounting plate by pivot bearings 15 and 16.

Pivot bearings 14, 15 and 16 are preferably of a friction type and can for example be of the type disclosed in New Zealand Patent Specification 212599/213772. Equally the pivot bearings can be of the type illustrated in our New Zealand Patent Specifications 212534 or 230905 or any of our earlier New Zealand Patents.

Also mounted between the frame and sash mounting plates 10 and 11 is an articulated arm 17. As shown the sash mounting plate 11 is thus longer than would customarily be the case for a four bar geometry stay. Articulated arm 17 is coupled at one end via pivot bearing 18a to the frame mounting plate 10 and at its other end via pivot bearing 18b to the sash mounting plate 11. Articulated arm 17 is formed by three links being link 19 extending from the frame mounting plate link 20 extending from the sash mounting plate and, according to the preferred embodiment, being significantly longer than link 19 with the two links being coupled together by an intermediate link 21. Pivot bearings 22a and 22b couples intermediate link 21 to links 19 and 20. All of these pivot bearings can be of a friction or non-friction type though the latter is preferred.

Locking means (hereinafter described) are provided to prevent longer link 20 from being able to move relative to the sash mounting plate 11 during normal operation of the stay.

Intermediate link 21 carries a pin 30 which forms a stop against which the shaped end 25 of link 20 (which projects beyond pivot 22a) can engage. Likewise on link 19 is formed a further stop 30a which can engage with a shaped portion 31 of link 21.

The components of the window stay are preferably formed from stainless steel and in an effort to keep the weight (and hence value) of stainless steel to a minimum a plastics material plate 32 is provided. The frame mounting plate 10 fits into a suitably shaped cavity in plate 32 in the manner shown and hence the combination of mounting plate 10 and plastics plate 32 form what would normally be considered to be a frame mounting plate. This composite plate is not only more economical to produce but provides an effective weight carrying component for the lower stay in a projected side hung window. This is achieved by portions of the arms 12, 13 and 19 where they loin with the frame mounting plate 10 being in sliding contact with the surface of the plastics plate 32.This provides support for the arms in the immediate vicinity of the pivot bearings 14 and 18a and thus serves to reduce loadings on not only the arms but also the pivot bearings.

In the closed position the short arm 12 is supported over a substantial part of its length thereby giving good support to carry the sash when in its closed position.

The end of the plate 32 over which the short arm 12 lies can be profiled as at 33 to provide a means of limiting the pivotal movement of arm 12 at its closed position.

With the window stay installed in the cavity between sash and frame and the sash in the closed position the stay has a configuration in which arm 12 is against stop 33; arm 13 lies over frame plate 10 and over part of the length of arm 12; arm 17 is folded so that link 21 lies over link 19; and sash plate 11 with link 20 lies over the foregoing links and arms. Even so the stay is compact and can fit within a cavity of say 13 x 32mm.

As the sash is opened arms 12 and 13 move in accordance with normal four bar stay geometry and links 19 and 21 of the articulated arm move to take up the position as shown in Figure 1 where the projecting end 31 of arm 21 engages with the stop 30a carried by arm 19. In such position the stay has reached the limit of opening allowed by links 19 and 21. Hence the degree of opening of the sash is restricted. During such opening of the stay the long link 20 is prevented from moving relative to the sash mounting plate 11 because of the engagement of the locking arrangement.

If further opening of the sash is required then the locking arrangement is released which permits link 20 to move relative to the sash mounting plate 11. Thus the sash can be opened up to a fully open position (when stop 30 engages with the end of the link 20) as shown in Figure 2. This generally corresponds with the sash being at ninety degrees to the opening in the frame.

When the sash is closed the locking mechanism automatically relatches so that when the window is next opened its degree of opening is limited in the manner described above.

In the illustrated form of this invention the locking arrangement is generally comprised of a latching means mounted with the sash mounting plate and a latch plate formed as part of projection 26 of the long link 20.

Projection 26 includes a longitudinally disposed slot 27 with an opening 29 extending into slot 27 from a side edge of longer link 20. A cam face 28, the purpose of which will hereinafter become apparent, extends from the edge of link 20 to slot 27.

In Figure 1 of the drawings the surface of sash plate 11 which is illustrated is the surface which mounts against the sash. Formed in sash plate 11 is a longitudinally extending recess 34. A slider 35 is located on the other, i.e. outer, surface of the sash plate 11 this slider having an elongate projection 36 which slidingly engages in a suitably dimensioned longitudinally extending slot 37 in plate 11. Attached to and extending from one end of projection 36 is an elongate plate 38 this plate having a thickness which enables it to locate within recess 34 when the sash plate 11 is mounted on the sash. A lug 39, projecting at a right angle to plate 38 has a return 40 at its outer end. A slot 39a is formed in sash plate 11 and through to this locates lug 39. Return 40 is thus positioned on the outer surface of the sash plate 11.

A bore 41 is formed in slider 35 and a spring 42 located in bore 41 engages at its outer end with an upstand 43.

The spring 42 thus biases slider 35 so that lug 39 locates at the distal end of slot 39a (relative to slider 35).

Referring to Figure 1 the part of lug 39 which projects through slot 39a fits within slot 27 of link 20 and thus prevents link 20 from pivoting about pivot 18b. However, if the slider 35 is manually moved toward the free end of sash plate 11 (i.e. against the spring bias of spring 42) lug 39 is moved along slot 39a so that it locates adjacent mouth 29 thereby allowing link 20 to be pivoted about pivot 18b. Therefore with the locking arrangement "unlatched" the window stay can be opened to its full extent as shown in Figure 2.

Due to the spring bias slider 35 will return to its normal position and thus lug 39 will locate against the aforesaid distal end of slot 39a. As the window stay is closed cam surface 28 engages with lug 39 and due to the profiling of cam face 28 this forces slider 35 against the spring bias so that link 20 can take up the position shown in Figure 1 whereupon lug 39 will re-enter slot 27 via opening 29 to automatically lock link 20 in the "latched" position. It is to be noted that in the latched position the elements of the locking mechanism are configured such that lug 39 is essentially only subjected to shear forces. Thus it is able to withstand forces which can arise by a user trying to force the window sash to open beyond the restricted open position.

In a preferred form of the invention link 21 carries a cam surface 44 which locates adjacent lug 39 so as to prevent movement thereof other than when the stay is in the fully closed position. As shown in Figure 1 cam 44 captures lug 39 within slot 27. Thus slider 35 can only be operated when the stay is in the fully closed position. Also slider 35, or the operating knob 48 (see below) can be provided with a key lockable locking device.

Referring to Figure 4 there is shown part of a window frame F and a window sash S carried by the stay of the present invention. A generally "S" shaped lever 46 is located within sash 5 and is fastened by fastener 45 to projection 36 of slider 35. The free end of lever 46 engages through a slot in sash S and preferably this free end 47 has attached thereto a suitably shaped operating knob 48. Thus when the window is in the closed position knob 48 can be slidingly moved relative to sash S which causes slider 35 to move and thereby release lug 39 from slot 27.

As will be apparent to those skilled in the art other forms of the locking arrangement can be used. For example the locking arrangement can be such that it is carried by the window sash rather than the actual stay itself. As shown in Figure 5 and 6 there can be provided a mechanism 50 comprising a mounting plate 51 from which projects a turret 52. A plunger 53 is slidingly mounted in turret 52 and has a bevelled end 54 which projects beyond plate 51.

Plunger 53 is connected to a lever 55 which has a profiled under surface 56 which engages with cam face 57 of the turret. Thus as lever 55 is moved so as to rotate plunger 53 surface 56 rides up cam face 57 to move plunger 53 axially and thus retract projecting end 54.

A lever arm 58 is pivotally mounted to turret 52. One end of lever arm 58 is engaged with lever 55 while the other end engages with a spring 59 in turret 53. Lever arm 58 is thus spring biased to the position shown in Figure 5.

In use turret 52 is located through an opening in the sash such that mounting plate 51 is located (in a preferred form flushly located) against and attached to the sash.

Thus when the mechanism 50 is mounted in a sash, end 54 of plunger 53 projects beyond the surface of the sash. The mechanism 50 is so located with sash that projecting end 54 engages in a suitable aperture formed in link 20. Thus link 20 is, as described with the earlier embodiment of the locking mechanism, locked against pivotal movement relative to the sash mounting plate 11 and hence the sash itself.

By rotating arm 55, however, plunger 53 is retracted thus withdrawing end 54 from the aperture in link 20. This permits link 20 to be able to pivot relative to the sash mounting plate 11.

To facilitate rotation of lever 55 a release mechanism 60 is mounted in a suitable position with the frame of the window. This release mechanism includes a body 61 having a push button 62 which is attached to a plunger (not shown) which extends through a projection 63 and is mounted to an engagement portion 64. Thus as button 62 is pushed into body 61 engagement member 64 rotates arm 55 thereby permitting release of the link arm 20. As the release mechanism 60 is mounted with the window frame the locking mechanism can only be released so as to permit pivotal movement of link 20 when the window is in a closed position.

In a conventional manner button 62 can be formed as part of a lock barrel which is key lockable.

To make the release mechanism "child proof" a release button 65 extends from body 61. This release button, when depressed, enables button 62 to be pressed inwardly to so move engagement member 64. Thus release mechanism 60 requires manipulation of buttons 65 and 62 simultaneously which generally is beyond the skill or capabilities of a young child.

In the preferred form of the invention the friction bearings in at least the sash and frame mounting plates are hollow, i.e. with throughbores, so that fixing screws can be located therethrough into the sash and frame. With the number of pivot points it is possible to rely solely on fixing screws through the pivots rather than separate screw holes in the frame and/or mounting plates. With the fixing screws so located there is additional strength and security of the installation. Due to the longer than normal length of sash plate 11, however, additional mounting apertures 49 can be included.

With up to eight friction bearings in each stay for a window installation a relatively high degree of frictional control at all angles of opening can be achieved as may be required for operation in some weather conditions. Thus it is believed that it is possible to use a smaller stay for a given sash width.

All of the sash plate bearings are assembled from one face and all the frame plate bearings are assembled from the other face and this provides for easy assembly processes.

As articulated arm 17 is located along the frame plate 10 from pivot 18a the front to back dimension can be kept to that of a normal 4 bar stay despite the presence of the locking mechanism. Also arm 17 does not interfere with the normal operation of the 4 bar link mechanism. Arm 17 considerably strengthens the stay in a violent over opening situation as can occur in strong winds.

In a modified form of the invention the locking arrangement can be adjustable so as to provide more than one initial angle of opening.

While articulated arm 17 has a specific restrictor function it is believed that it can improve the carrying capacity of the stay. Also it is believed arm 17 may improve opening of the stay as it lessens the force in the important short-arm which is the highest loaded member in a 4 bar stay.

Claims (12)

1. A window stay comprising a first mounting plate

coupled by coupling means to a second mounting plate, said coupling means including at least one arm which is respectively pivotally connected at or near each end to said first and second mounting plates, characterized in that an articulated arm is also coupled between said first and second mounting plates.

2. A window stay as claimed in Claim 1 further including a releasable locking means which, unless released, prevents a part of said articulated arm being movable relative to the mounting plate to which said part is coupled.

3. A window stay as claimed in Claim 1 or 2 wherein said coupling means is formed by a pair of arms one of which is significantly longer than the other.

4. A window stay as claimed in Claim 3 wherein the pivot points of said pair of arms are such that when said stay is in a closed position a portion of one arm overlaps a portion of the other arm.

5. A window stay as claimed in any one of preceding Claims 2 to 4 wherein said articulated arm comprises a first arm section pivotally coupled by one end to said second mounting plate and releasably locked against pivotal movement relative to said second mounting plate, a second arm section pivotally coupled to said first mounting plate and an intermediate arm section pivotally coupled between said first and second arm sections.

6. A window stay as claimed in Claim 5 wherein limit means are provided whereby the extent of relative pivotal movement between said intermediate and second arm sections is limited.

7. A window stay as claimed in Claim 2 or 5 wherein the locking means is only releasable when the stay is in a closed position.

8. A window stay as claimed in Claim 7 wherein said releasable locking means comprises a slider carried by said second mounting plate, said slider and said first armsection including a latching arrangement which latches said first arm section and said second mounting plate against relative movement, said intermediate arm section including means which prevent said latching arrangement from becoming unlatched except when the stay is in the closed position.

9. A window stay as claimed in Claim 7 or 8 further including operating means associated with said locating means whereby said locking means can be operated remote from a window cavity in which said stay is located.

10. A window stay as claimed in Claim 9 wherein the operating means is key lockable.

11. A window stay as claimed in any one of the preceding Claims wherein at least part of the first mounting plate is located within a recess in a plastics material plate.

12. A window stay substantially as herein described with reference to the accompanying drawings.