GB2323123A - Friction stay and assembly - Google Patents

Abstract

In a friction stay comprising a track (40), a sash arm (12), a strut pivotally connected to the track by a primary pivot (48) and pivotally connected to the sash arm by a secondary pivot, a slider (76), a first link which is pivotally connected to the slider (76) and the sash arm (12), and a second link which is pivotally connected to the slider (76) and the strut, a retainer (46) which engages an end of the sash arm (12) is movable with respect to the track (40). The primary pivot (48) is also movable relative to the track (40). The retainer (46) and primary pivot (48) may be mounted on a common band movable relative to the track so that they are adjusted simultaneously.

Description

FRICTION STAY AND ASSEMBLY FIELD OF THE INVENTION This invention relates to a friction stay, and in particular to a friction stay for mounting a movable panel relative to a fixed frame. The invention also relates to an assembly of a panel movable relative to an outer frame, with two opposed edges of the panel pivotably secured to the frame by respective friction stays. The application of the invention for mounting a window in a fixed frame is likely to be the most common, and so much of the following description will relate to such use. However, other applications are not thereby excluded. The invention disclosed herein is an improvement upon that of my copending application GB 9622202.1.

BACKGROUND TO THE INVENTION Traditional windows stays were used to retain an opening window, the stay being separate from the hinge. However, recent developments in window stays has led to a stay which also provides a pivot about which the window can move between its open and closed conditions, so that a separate hinge is not required. Such a stay may include a friction element by which the window can be held in its open or partly open condition.

Typically, there are two friction stays fitted to an opening window: if the window opens about a substantially horizontal axis the friction stays are fitted to opposite side edges of the window; if the window opens about a substantially vertical axis the friction stays are fitted to the top and bottom edges of the window.

Window stays are required to satisfy two major criteria if they are to be acceptable and useful in practice.

The first of these criteria is that the window stays must be sufficiently strong to resist jemmying of the window, i.e.

to resist the force which an unauthorised intruder might apply in an attampt to force the window away from the surrounding frame. Accordingly, most window stays are made of metal, of thick enough section to resist the expected jemmying forces.

The second of the criteria is the ability to adjust the position of the window relative to the frame to compensate for the sag or other unwanted movement of the window which may occur during its lifetime. Such unwanted movement is particularly likely for large windows and those incorporating multiple layers of glass, such movement perhaps being unsightly and increasing the likelihood that the window will not remain totally weatherproof.

DESCRIPTION OF THE PRIOR ART An early window stay with a friction element is disclosed in GB 2,244,513. This document discloses a window stay having a track which in use is secured to the frame. The track carries a slider to which is pivotably mounted one end of the sash arm, the sash arm in use being connected to the window. The track also has a pivot for one end of a strut, the other end of which strut is pivotably mounted to a point on the sash arm. It will be understood from this document that pivotting movement of the sash arm (as when the window is opened) causes the slider to move along the track, the friction between the slider and the track acting to retain the window in an open or partly open condition.

Because the one end of the sash arm is retained in alignment with the track, this type of window stay is suitable for use with a window which in the closed condition is typically substantially located within the surrounding frame, such as the traditional designs of wooden windows.

The above stay is not, however, suitable for a plastic window, which in the closed condition will typically have a peripheral lip overlying a part of the surrounding frame.

The lip is provided to carry a seal, which firmly engages the part of the frame which it overlies, the seal helping to ensure adequate weather sealing for this type of window.

For plastic windows (and other types having a peripheral lip) the action of the stay is necessarily more complex, since both ends of the sash arm must move away from the track during opening movement of the window (so that the lip does not foul a part of the frame). The increasing popularity of plastic windows as above described has resulted in the development of a particular type of window stay to accomplish the complex action required, and such a window stay is generally referred to as a "four bar linkage friction stay".

Because this invention is directed to stays with this complex action, for brevity the term "friction stay" will herein refer to stays of the "four bar linkage" type, unless the context requires otherwise. Additional developments, such as stays with five (and perhaps more) links, are also to be encompassed by this term.

Fig.l shows a prior art friction stay 2, as above defined.

This stay has a track 4 which is fixed to the frame 6 (shown in dashed outline). A slider'8 is mounted upon the track 4, and is movable therealong. A first link 10 is provided, and has one of its ends pivotably connected to the slider 8.

The other end of the first link 10 is pivotably connected to the sash arm 12 which is fixed to the window 14 (also shown in dashed outline). A strut 16 has one of its ends pivotably connected to the track 4 (the pivot between the strut and the track being referred to herein as the primary pivot); the other end of the strut is pivotably connected to the sash arm 12. A second link 18 has one of its ends pivotably connected to the slider 8 and the other of its ends pivotably connected to the strut 16. The strut 16 is cranked at 20, and the sash arm is cranked at 22, so that in the closed condition of the window the sash arm 12 overlies the track 4 with the links 10,18 and strut 16 located therebetween. Fig.l also shows the lip 24 of the window, which carries a seal (not shown) adapted to engage the surface 26 of the frame 6.

It will be understood that it is the presence of the lip 24 (which is typical of plastic windows in particular) which requires the complex action of the friction stay, since with the window stay according to GB 2,244,513 for example the lip would foul the frame as the window is opened.

If an unwanted intruder was seeking to jemmy the window 14, typically a tool would be inserted in an effort to force the lip 24 away from the facing frame surface 26. Because there is no direct connection between the track 4 and the sash arm 12, friction stays are more susceptible to such jemmying than the window stays in Which the sash arm is directly pivoted to the track, or is connected thereto by way of a slider.

In order to prevent such jemmying, or at least to reduce its likelihood of success, the known friction stay of Fig.l has a retainer 28 which is designed to locate the end 30 of the sash arm 12 when the window is in the closed condition, the retainer inhibiting lateral movement of the sash arm away from the track and so resisting a force seeking to separate the lip 24 from the surface 26.

In order to permit adjustment of the position of the window, the friction stay of Fig.1 has a number of elongated fixing holes. Two elongated fixing holes 32 are provided in the track 4, to fix the track 4 to the frame 6; two elongated holes 34 are provided in the sash arm 12, to fix the window 14 to the sash arm 12.

When it is desired to adjust the position of the window 14 relative to the frame 6, the screws securing the elongated holes 32 and/or 34 may be loosened, whereupon the track 4 may be moved relative to the frame 6, or the window 14 may be moved relative to the sash arm 12, or both, as desired to counteract the unwanted movement of the window. In addition, however, the track 4 and sash arm 12 have a respective circular hole 36,38 each of which accommodates a fixing screw, which fixing screw must be removed before the above adjustment can take place.

It will be understood that with plastic windows, the fixing screws are often secured directly into the plastic wall of the frame or window. In practice, it may be impossible to tighten the screws in the elongated holes sufficiently to prevent movement of the track or window, so that the screws passing through the circular holes are providing most if not all of the fixing for the stay upon the frame, and the fixing for the window upon the stay. It is a recognised problem with the known friction stay that following removal of the fixing screw from one or both of the circular holes 36,38, i.e. if it is necessary to move the track or sash by 1 millimeter or so, the ability to tighten the fixing screw into a (partially) new fixing hole in the plastic will be much impaired. Also, the ability to tighten the screws fitted through the elongated holes is also often impaired by untightening and subsequent retightening of the fixing screw.

In addition, the friction stays are adapted to be located between the frame and the window, which will typically open outwardly so that the fixing screws securing the sash arm to the window will be particularly difficult to access to tighten and untighten as necessary, often requiring the user to lean partially out of the opened window to achieve this task.

GB 2,284,014 is a modification of the known friction stay in which the primary pivot, i.e. that between the strut and the track is movable relative to the track. Movement of the primary pivot in one direction will increase the engagement between the end of the sash arm and the retainer when the window is in the closed condition; however, movement in the other direction will reduce the engagement, so that the ability of the friction stay to resist jemmying might be reduced in some positions of the primary pivot.

DISCLOSURE OF THE INVENTION It is an object of the invention to seek to overcome or reduce the problems associated with adjustment of the prior art friction stays, yet without impairing the ability of the stay to resist jemmying of a window to which the stay is fitted.

According to the invention, therefore, there is provided a friction stay comprising a track part, a sash arm, a strut which is pivotably connected to the track part by a primary pivot and pivotably connected to the sash arm by a secondary pivot, a slider, a first link which is pivotably connected to the slider and to the sash arm, and a second link which is pivotably connected to the slider and to the strut, a retainer which is engageable by an end of the sash arm, the primary pivot being movable relative to the track, characterised in that the retainer is also movable relative to the track.

Because both the primary pivot and the retainer are movable relative to the track, the spacing between them can be maintained substantially unchanged, so that the degree of engagement between the sash arm and the retainer in the closed condition can be maintained despite adjustment of the position of the primary pivot.

In addition, because the adjustment of the window to which the sash arm is connected is achieved by movements of the primary pivot (and corresponding movements of the retainer), the track itself is not required to move, so that only circular fixing holes are required to be provided in the track. Also, it is not necessary to loosen or remove the fixing screws to effect adjustment, so that no weakening of the plastic supporting those screws should occur.

We have furthermore realised that with a friction stay according to the invention all of the adjustment which will usually be required for a fitted window can be carried out by movement of the primary pivot and retainer relative to the track, i.e. adjustment of the position of the sash arm relative to a fitted window is not required. Accordingly, the holes for the fixing screws which are to secure the window to the sash arm may be circular; since these screws are not required to be loosened or removed to effect adjustment of the window no weakening of the plastic supporting these screws should occur, and in addition the inconvenience and difficulty of accessing these screws to effect adjustment is avoided.

Preferably, the retainer and primary pivot are mounted on a common member, the member being substantially rigid so that the spacing between the primary pivot and the retainer is thereby maintained. Preferably also, the common member is carried by the track and is retained thereby.

Usefully, the common member carries a locating peg, the peg being securable at any one of a number of positions relative to the track, so that the common member has a dicrete number of available secured positions; alternatively, the common member carries a friction element which can be secured relative to the track at any desired position between two predetermined extremes.

We also provide a window and/or frame component fitted with a friction stay according to the invention.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig.l is a side view of a partly opened prior art friction stay, with the window and frame parts shown schematically in dashed outline; Fig.2 is a side view of a partly opened friction stay according to the invention; Fig.3 is an enlarged view of portion III of Fig.2; Fig.4 is an enlarged view of portion IV of Fig.2; Fig.5 is a sectional view along the line V-V of Fig.3; Fig.6 is a sectional view along the lines VI-VI of Fig.4; Fig.7 is a sectional view along the lines VII-VII of Fig.6; Fig.8 is a sectional view of Fig.6 at a grub-screw location; Fig.9 is a view of portion III from below; and Fig.10 is a view of portion IV from below.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In this specification the terms "open", "partly open" and "closed" will be used to refer to conditions of the stay which respectively correspond to the open, partly open, or closed conditions of a window when the stay is mounted thereto.

The operation and components of the prior art friction stay of Fig.l is described above in the description of the prior art. Several components of the friction stay according to the invention are identical and/or perform the same function as components of the prior art friction stay; repetition of the components or their function will not be repeated unless relevant to the invention.

In the friction stay according to the invention as shown in Figs.2-l0, the adjustment is available by way of the track 40, so that the fixing holes 42 in the sash arm 44 are all circular. Accordingly, following correct fitment of the friction stay, it is envisaged that it will not be necessary to remove and reposition the sash arm. Accordingly, all of the fixing holes 42 can cooperate to secure the sash arm to the window (not shown in Fig.2), rather than relying in part upon a friction fit of a screw into an elongated fixing hole. In addition, because it is envisaged that the screws locating in the fixing holes 42 will not require to be loosened, the security with which they can engage the plastic window should not change during the time that the window is connected to the friction stay.

According to the invention, both of the retainer 46 and the primary pivot 48 are movable relative to the track 40. It will be understood that movement of the primary pivot 48 will effect adjustment of the window position relative to the frame (to cater for sag during its lifetime, for example). However, in order to maintain the spacing between the primary pivot 48 and the retainer 46, the retainer 46 is also movable relative to the track 40.

It is a feature of the invention that the spacing between the primary pivot 48 and the 'retainer 46 can be maintained at a predetermined distance so that the end 50 of the sash arm 44 can cooperate with the retainer 46 in the closed condition of the stay, for any position of the primary pivot.

In certain less preferred embodiments of the invention the primary pivot 48 and the retainer 46 are independently movable relative to the track 40, but in the preferred embodiment shown and as more fully described below they are interconnected by a substantially rigid member or band 52.

As better seen in Figs. 6 and 7, the primary pivot 48 is connected to a shoe 54 which can slide by a limited amount relative to the track 40, being held against the track 40 by the overlying lips 56.

The shoe 54 carries a pair of grub screws 58a,58b, the pointed end of which can engage in each of a number of spaced apertures 60 in the base of the track 40.

Accordingly, by way of the grub screws 58a,b, the shoe 54, and thus the primary pivot 48, may be secured in any one of seven positions relative to the track 40. One of the overlying lips 56 of the track carries graduation marks 62, with which the arrow 63 may be aligned when the point of a grub screw 58a,b is aligned with an aperture 60.

The shoe 54 is connected to one end the band 52 by the primary pivot 48. The other end of the band 52 is connected by rivet 64 to the arm 66 which is integral with the retainer 46. Accordingly, movements of the shoe 54 along the track are communicated to the retainer 46 by the band 52, so that the retainer 46 moves by the same distance as the shoe 54, and thus also by the same distance as the primary pivot 48, so ensuring the predetermined spacing between the retainer 46 and the primary pivot 48 is maintained.

In this embodiment the apertures 62 are each spaced apart by 2mm and the grub screws 58a,b are spaced apert by 7mm.

Accordingly, one or other of the grub screws 58a,b can enter an aperture at lam intervals. There are seven graduations 62 corresponding to the seven possible grub screw fitment positions with lam intervals.

It is another feature of the design according to the invention that it is envisaged that the track 40 will also not require to be moved relative to the frame after the friction stay has been correctly fitted. Thus, adjustment of the position of the window relative to the frame can be effected by movement of the shoe 54 and retainer 46, rather than movement of the track itself. Accordingly, the fixing holes 68 in the track 40 are all circular and so can cooperate fully to secure the track to the frame (not shown in Figs.2-8), rather than relying in part upon a friction fit of a screw into an elongated fixing hole.

However, since the band 52 overlies the base of the track 40, it is necessary to provide apertures 70 in the band through which the fixing screws may be passed. In this embodiment, the apertures 70 are of a size to pass around the head of standard sized fixing screws, so that when adjustment of the position of the primary pivot 48 and retainer 46 is required it is only necessary to release the respective grub screw 58a,b from its aperture 60 and move the shoe 54 until one of the grub screws can engage another aperture 60.

However, the apertures 70 are small enough (in the direction perpendicular to the longitudinal axis of the track 40) so as to be engageable by the head of a larger-headed fixing screw if the user desires to use such a screw or screws, so that when tightened the head of the larger-headed fixing screw(s) will engage the band and assist in maintaining it in place relative to the track. Notwithstanding that to adjust the position of the primary pivot and retainer of such an embodiment will require the larger-headed fixing screw(s) to be loosened to permit movement of the band, this may be acceptable to some users, and perhaps be justified in terms of the increase in positional security of the primary pivot and retainer relative to the track which such an embodiment provides.

An upstanding stop 72, suitably pressed out of the base of the track, limits the movement of the shoe 54 towards the right in Fig.4 (towards the bottom of the page in Fig.2); an upstanding flange 74 on the other end of the track limits the movement of the retainer towards the left in Fig.3 (towards the top of the page in Fig.2). The stop 72 and flange 74 limit the movement of the shoe 54 to the seven positions identified by the graduations 62.

The slider 76 carries a grub screw 78, which can be tightened against the band 52 to increase the frictional resistance to movement of the links, i.e. to increase the frictional resistance to opening and closing of a fitted window.

It will be understood that when it is required to adjust the position of the closed window relative to the frame, it is first necessary to open the window to expose the grub screws 58a,b (together with the larger-headed fixing screw(s) , if fitted). The respective grub screw 58a,b is loosened so that the point of the grub screw is released from the respective aperture 60 (and the larger-headed fixing screw(s) are loosened if necessary); the shoe 54 is then moved to align the grub screw with another of the graduation marks 62. If the window is then correctly re-positioned, the grub screw 58 (and the larger-headed fixing screws, as appropriate) are subsequently re-tightened to secure the window in its new position relative to the frame.

It will be understood that even if the user has fitted one or more larger-headed fixing screws which are required to be loosened prior to adjustment, the respective grub screw 58a,b can secure the shoe 54 (and retainer 46) sufficiently to check that the window has been correctly re-positioned, i.e. the window can be opened and closed several times to check for adequate sealing etc. prior to the fixing screw(s) being re-tightened. Accordingly, the fixing screw(s) are not required to be loosened and re-tightened more than once for each adjustment of the window, so that the likelihood of significant weakening of the threads therefor is much reduced.

However, in the preferred embodiment shown it is not necessary to loosen any of the fixing screws, adjustment being possible following loosening of the respective grub screw 58a,b only.

It will also be understood that the window will typically be mounted upon two friction stays according to the invention; in certain cases, both friction stays will require adjustment as above, but this can be undertaken separately and sequentially for each stay, as desired.

Furthermore, it is a particularly beneficial feature of the invention that access to the grub screw(s) (and the fixing screws, where applicable) will usually be readily obtainable, i.e. the grub and fixing screws are mounted upon the window frame and will be exposed on opening of the window; access thereto will not require the user to lean out of the window as was the case with the prior art friction stay i.e. when adjustment of the window relative to the sash arm was required.

As is customary in this art, the track 40 is of stainless steel, as are all of the links of the friction stay. The slider 76, as well as the shoe 54, is made of PVC, though in other embodiments any material which is strong enough to support the pivots, and yet which can readily slide in the track 40, can be used. The grub screws 58a,b are usefully of brass, and the band 52 is usefully of stainless steel.

As above indicated, the spacing between the apertures 60 is 2mm, so that 6mm of movement is available between one extreme grub screw location and the other extreme grub screw location. Whilst this amount of available movement is small, it is believed to be sufficient to overcome the window sag which will occur for all or at least most of the applications in which friction stays are used. If, however, additional adjustment is believed likely to be necessary then more apertures 60 can be provided. Also, the lmm increments of adjustment are believed to be suitable for adjustment of all or at least most friction stay applications; again, however, smaller increments, i.e apertures with a smaller spacing therebetween, may be provided if necessary or desirable in certain applications.

Clearly, however, the spacing between the apertures 60 should be large enough so that the grub screw 58a,b can obtain a secure location therein, and we believe that 2mm is a realistic spacing for this purpose.

Preferably, the friction stay will be manufactured and sold with the shoe 54 at its central location, so that subsequent adjustment in either direction relative to the track is possible.

Claims (15)

1. A friction stay comprising a track part, a sash arm, a strut which is pivotably connected to the track part by a primary pivot and pivotably connected to the sash arm by a secondary pivot, a slider, a first link which is pivotably connected to the slider and to the sash arm, and a second link which is pivotably connected to the slider and to the strut, a retainer which is engageable by an end of the sash arm, the primary pivot being movable relative to the track part, the retainer also being movable relative to the track part.

2. A friction stay according to claim 1 in which the retainer and primary pivot are mounted on a common member which is movable relative to the track part.

3. A friction stay according to claim 2 in which the common member is substantially inextensible.

4. A friction stay according to claim 2 or claim 3 in which the common member is carried by the track part and is retained thereby.

5. A friction stay according to any of claims 2-4 in which the common member carries a locating peg, the peg being securable at any one of a number of positions relative to the track part.

6. A friction stay according to claim 5 in which the track part has a number of apertures, and in which the locating peg is a grub screw, part of the grub screw being locatable in an aperture to define a position of the common member relative to the track part.

7. A friction stay according to claim 6 in which the apertures are arranged in a single line, the apertures being spaced at 2mm intervals, and in which there are two grub screws arranged an odd number of millimetres apart, the grub screws being co-linear with the apertures.

8. A friction stay according to any of claims 2-4 in which the common member carries a friction element which can be secured relative to the track at any desired position between two predetermined extremes.

9. A friction stay according to any of claims 1-8 in which the sash arm has at least one fixing hole for receiving a fixing means, the or each hole being circular.

10. A friction stay according to any of claims 1-9 in which the track part has at least one fixing hole for receiving a fixing means, the or each hole being circular.

11. A friction stay according to any of claims 2-10 in which the primary pivot is mounted upon a slidable member, the slidable member being secured to the common member.

12. A friction stay according to claim 11 in which the primary pivot secures the slidable member to the common member.

13. An assembly comprising a panel and an outer fixed frame, two opposed edges of the panel being pivotably secured to the frame by respective friction stays according to any of claims 1-12, each friction stay being secured to the frame by way of its track part, and to the panel by way of its sash arm.

14. An assembly according to claim 13 in which fixing means secure the respective parts of the friction stay to the frame and panel, and in which part of the fixing means engages the common member

15. A friction stay constructed and arranged substantially as described in relation to Figs.2-10 of the accompanying drawings.