NZ528293A - Friction bar assembly - Google Patents

Abstract

A window friction bar assembly (100) comprises first and second link arms (3, 12) which have pivot bores (4,6 14, 16) at each end, and first and second attachment plates (8, 18) for attaching the first and second link arms (3, 12) to a window frame through the pivot bores (6, 16). At least one of the attachment plates (8, 18) constitutes a friction attachment device (20), having a hollow cylindrical protrusion (26) on one side, with an outside diameter to allow a sliding fit inside the pivot bore (6, 16). A screw 30 adapted for screwing into the window frame, has a head formed with a radiused face on an inside, so as to expand an end rim (32) of the hollow cylindrical protrusion (26) when tightened, and thereby provide a frictional attachment between the link arm (3, 12) and the attachment plates (8, 18).

Description

Patents Form No. 5 Fee No. 2: $250.00 5282 93 PATENTS ACT 1953 After Provisional No: 528293 Dated: 19 September 2003 intellectual property office of n.z. 2 0 SEP 2004 RECEIVED COMPLETE SPECIFICATION FRICTION BAR ASSEMBLY We Aluminium Systems NZ Limited, of 3 Timaru Place, Mt Wellington, Auckland, New Zealand, a New Zealand company, hereby declare the invention for which w^ pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement: 1 (the following page is numbered la) la TECHNICAL FIELD The present invention relates to a friction bar assembly for supporting and holding an openable window in an optional opened condition. However, it is to be understood that the invention is not to be limited as such. Moreover, because the invention may have many other applications, the prior art and possible applications of the invention discussed below are given by way of example only.

BACKGROUND ART Conventional friction bar assemblies for supporting and holding an openable window in an optional opened position generally use an adjustable swinging friction connector comprising a single base plate which is secured to a side of a window frame, and connection links which are attached to the side sash of the opening window. One well known type of friction bar assembly has two pivoting connection links, with one of the links having an adjustable friction connection. Another type has a pivoting connection link and a sliding friction connection link.

However even though these have an adjustable friction connection, there is always a certain amount of friction at the connection, even prior to installation, making it difficult to easily fold the friction bar assembly for packing and handling.

Moreover, the friction connection usually involves metal to metal contact, which can result in wear. Furthermore, depending on design, the friction adjustment screw can become loose with frequent use thus altering the friction setting.

DISCLOSURE OF THE INVENTION It is an object of the present invention to address the above problems with conventional friction bar assemblies, or to at least provide the public with a useful choice.

According to a first aspect of the present invention there is provided a friction bar assembly for supporting and holding an openable window in an optional opened position, comprising: a first link arm having a sash pivotal connection bore and a frame pivotal connection bore at opposite ends thereof; a first attachment device adapted for attaching the first link arm to an inner peripheral face of a window frame through the frame pivotal connection bore; 2 a second link arm having a sash pivotal connection bore and a frame pivotal connection bore at opposite ends thereof; a second attachment device adapted for attaching the second link arm to an inner peripheral face of the window frame through the frame pivotal connection bore; and a friction device for providing frictional attachment between at least one of the link arms and the attachment device, wherein at least one of the first and second attachment devices comprises an attachment plate having a hollow cylindrical protrusion on one side thereof, with an outside diameter to allow a sliding fit inside the pivotal connection bore, and the friction device comprises in combination, the hollow cylindrical protrusion and a screw having a threaded end adapted for screwing into the frame or a member attached to the frame, and a head formed with a radiused face on an inside thereof, so as to deform an end rim of the hollow cylindrical protrusion outwards when tightened, and thereby provide a frictional attachment between the link arm and the attachment plate.

With such a construction, by providing the hollow cylindrical protrusion and the screw formed with the head portion radiused so as to deform the end of the hollow cylindrical portion outwards, the pivotal connection can be kept free and substantially frictionless until assembled with the screw, thus allowing the components to be easily folded for packaging and handling. Moreover the friction attachment can be easily 20 adjusted by simply tightening or loosening the screw.

The radiused face of the screw may be such that when tightened against the end rim of the hollow cylindrical protrusion, the screw head has substantially no contact with the link arm.

By this configuration, the screw can be kept from coming undone with repeated 25 pivoting of the link arm, and since there is no metal to metal contact, wear is minimised. Moreover, the thread of the screw may be distorted to give a locking action when tightened, further preventing the screw from coming undone.

The screw may be threaded into the attachment plate, or into the window/sash frame directly or by using a captured nut such as a Riv-nut™, or into both the attachment 30 plate and the window/sash frame. 3 Furthermore, the attachment plate may comprise hollow cylindrical portions formed integral with the attachment plate and extending from either side thereof and coaxial with an aperture through the attachment plate which constitutes the pivotal connection means, and a screw for threading into the cylindrical portions, the internal 5 diameter of the hollow cylindrical portions being set so as to provided suitable expansion -T — ' of the cylindrical portions when threaded by the screw to thereby lock the attachment plate to the frame, and also contribute to a frictional force between the attachment plate and the link arm. Also with this configuration,Jhe^serew may be formed with a head portion radiused so as to deform the end of the hollow cylindrical portion on the link arm 10 attachment side outwards, when tightened such the screw head has substantially no contact with the link arm.

Furthermore, the attachment plate may comprise one or more protrusions on a rear side thereof for fitting into a hole in the window or sash frame to provide a secure keyed location, and or one or more holes for accommodating a fastener such as a screw.

With any of the above adjustment means, the loading between the abutting friction surfaces can be easily adjusted by tightening of the screw. Hence as the condition of the friction surfaces changes with time, the friction function can be maintained. Moreover, the loading can be adjusted to suit different sizes and orientations of windows.

Furthermore the attachment plate may comprises one or more protrusions on a rear 20 side thereof with an axis spaced apart from an axis of the hollow cylindrical portion. By this construction the attachment plate can be securely attached to a nut plate attached to the frame.

According to another aspect of the present invention, the friction bar assembly further comprises a nut plate having a flat face on one side for mounting on a window 25 frame and at least one hole formed therein for accommodating the protrusion of the attachment plate, and a cylindrical threaded portion protruding from an opposite side thereof and adapted for insertion into the hollow cylindrical portion, to provide a metal thread on the inside.

By providing the nut plate, the frictional attachment may be accurately controlled, 30 by suitable design, compared to for example where the screw is simply screwed into the window frame. 4 Preferably the nut plate has a raised section surrounding the cylindrical threaded portion for fitting into a recess formed in the attachment plate.

By having a raised section surrounding the cylindrical threaded portion, the attachment plate can be more securely supported.

According to another aspect of the present invention, the nut plate may be provided at each end of an elongate base plate and integral therewith.

By providing the elongate base plate with the nut plate sections at each end, the assembly can be made to a required configuration as a complete assembly, thus facilitating installation. Moreover, since there is no friction at the connection between the members 10 prior to fitting, the assembly can be easily folded for packing.

The friction bar assembly may further comprise third and fourth attachment means of a similar construction to the first and second attachment means.

The invention also includes an attachment plate for a friction bar assembly comprising a hollow cylindrical protrusion on one side thereof, with an outside diameter 15 to allow a sliding fit inside a pivotal connection bore of a link arm of a friction bar assembly having a sash pivotal connection bore and a frame pivotal connection bore at opposite ends thereof.

Moreover the invention includes the above attachment plate connected by connection means to a nut plate provided with a thread to take a thread of a screw, the nut 20 plate comprising a flat section and a protruding cylindrical section, the protruding cylindrical section being provided with the thread, and with an outside diameter to allow fitting inside the bore of the cylindrical portion of the attachment plate.

According to another aspect of the present invention, there is provided a method of providing a support for an openable window, involving fitting a friction bar assembly 25 according to the invention between the window sash and the window frame.

Moreover, the above method may further comprise, when fitting the friction bar assembly, clamping a jig plate with holes drilled at suitable spacing, in position on the frame or sash, and drilling holes in the frame or sash using the jig plate holes for a guide.

The jig plate may have several holes, which can be appropriately selected depending on location requirements for drilling the frame and sash. Moreover, the jig plate may be adjustable, e.g. telescopic, for added versatility.

The present invention may also broadly be said to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more of the parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.

BRIEF DESCRIPTION OF THE DRAWINGS Further aspects of the present invention will become apparent from the ensuing description which is given by way of example only and with reference to the accompanying drawing in which; FIG. 1 is a side view of a friction bar assembly for supporting and holding an openable window in an optional opened condition, according to a first embodiment of the present invention, illustrating an arrangement of components in relation to a window frame and sash, and also showing a side and end view of a jig plate used for forming holes in the frame and/or sash.

FIG. 2 shows details of one type of attachment plate of the friction bar assembly of FIG. 1 in relation to a first link arm.

FIG. 3 shows details of the attachment plate of FIG. 2.

FIG. 4 shows details of an adjustable friction attachment device which provides frictional attachment of a pivotal link arm to a sash attachment plate or a frame attachment plate, in the case of the attachment plate of FIG. 2.

FIG. 5 shows details of another adjustable friction attachment device similar to that of FIG. 4, but using a Riv-nut™.

FIG. 6 shows details of yet another adjustable friction attachment device similar to that of FIG. 4 and FIG. 5, but using a single moulded attachment plate. 6 FIG. 7 is a side view of a friction bar assembly according to a second embodiment of the present invention, similar to the configuration of FIG. 1, by with an elongate base plate.

FIG. 8 shows details of one type of attachment plate of the friction bar assembly of 5 FIG. 7 in relation to a first link arm.

FIG. 9 shows the components of the friction bar assembly of FIG. 7, assembled in plan view, and disassembled in side view.

FIG. 10 is a perspective view of the assembled friction bar assembly of FIG. 7.

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will now be described with reference to the figures.

As shown in FIG. 1, a first embodiment of a friction bar assembly of the invention generally denoted by arrow 1, for supporting and holding a sash 2 of an openable window in an optional opened position, comprises: a first link arm 3 which has a sash pivot bore 4 15 and frame pivot bore 6 (pivotal connection bores) at opposite ends thereof; a first attachment plate 8 which is adapted for attaching the first link arm 3 to an inner peripheral face of a window frame 10 (only the top frame shown) through the frame pivot bore 6; a second link arm 12 which has a sash pivot bore 14 and a frame pivot bore 16 at opposite ends thereof; a second attachment plate 18 which is adapted for attaching the second link 20 arm 12 to the inner peripheral face of the window frame 10 through the frame pivot bore 16 at an optional spacing X from the first attachment plate 8; and a friction attachment device generally denoted by arrow 20 (to be described in detail with reference to FIG. 2 to 6).

The friction attachment device 20 provides a frictional attachment between the first 25 link arm 3 and the attachment plate 8, and the second link arm 12 and the attachment plate 18, such that when the attachment plates 8 and 18 are fitted to the window frame 10 of a window, the link arms 3 and 12 are held in position, once moved to a desired position by opening or closing the window. Moreover in this embodiment, third and fourth attachment plates 22 similar to the attachment plates 8 and 18 are provided at the sash 30 pivot bores 14 and 4 and are also fitted with similar friction attachment devices 20. 7 In this embodiment, as shown in detail in FIG. 2 to FIG. 6, the attachment plates 8, 18, 22 comprises a plate member 24 of a suitably small size which can be easily mounted on the flat surface of a range of window frame profiles (or sash profiles). A protrusion 25 (FIGS. 3) is provided on a rear side of the plate member 24 towards one end for inserting 5 into a hole drilled in the window frame 10 (or the sash 2) to provide a secure keyed location. A countersunk hole 28 (FIGS. 3) is also provided towards the other end for accommodating a fastening screw. A hollow cylindrical protrusion 26 is provided on a front side of the plate member 24 to serve as a pivotal connection means, by fitting into the pivot bores 4, 6, 14 or 16 formed in the end of the link arms 3 and 12. The outside 10 diameter of the cylindrical protrusion 26 is so as to allow a snug sliding fit inside the pivot bore 4, 6, 14 or 16. As typically shown in FIG. 2, the inside of the pivot bores 4 and 6 (14 and 16) are formed surrounded by a countersunk portion to accommodate outward expansion of a top end rim 32 of the cylindrical protrusion 26 as described later.

In the example shown in FIG. 2 and 3, a metal nut plate 29 is provided for fitting 15 to the plate member 24, to provide a metal thread section to ensure secure fastening of an adjustment screw 30.

The metal nut plate 29 is press formed with a raised section 38 surrounding a cylindrical threaded portion 31. The raised section 38 fits into a recess 38' formed in the plate member 24, and the cylindrical threaded portion 31 is inserted into the hollow 20 cylindrical portion 26 of the attachment plate8, 18, 22, to provide a metal thread on the inside. By having the raised section 30 surrounding the cylindrical threaded portion 31, the attachment plate 8, 18, 22 can be more securely supported and clamped when assembled. Apertures 29' are provided at each end of the metal nut plate 29 for either fitting over the protrusion 25 or for taking a fastening screw.

Here the adjustment screw 30 also serves as an attachment device in conjunction with the attachment plate 8,18, 22, for attaching the link arm 3 or 12 to an inner peripheral face of a window frame 10 (or the sash 2), As can be understood by reference to FIG. 4, which shows a sectional plan view for the first link arm 3 attachment described later, once the first link arm 3 is fitted to the central cylindrical protrusions 26, the 30 adjustment screw 30 is inserted into the hole and tightened to thereby clamp the first link arm 3 tight against the face of the attachment plate 8 and expand the end rim 32 of the cylindrical protrusions 26 outwards to assist in providing a frictional engagement. At this 8 time the expanded end rim 32 is accommodated in the countersunk portion of the pivot bore 6, which has a cross-section radius to conform to the under-head radius of the adjustment screw 30.

Moreover, the screw threads into a self tapped thread 33 formed in the sash 2 to 5 secure the attachment plate 8 plate in place on the sash 2. As shown in FIG. 4, the adjustment screw 30 is formed with an under head portion radiused so as to expand the end rim 32 of the hollow cylindrical portion 26 outwards when tightened, such the screw head does not contact with the link arm 3. Such an arrangement helps to prevent the adjustment screw 30 coming undone with repeated pivoting of the link arm 3. Moreover, 10 the thread of the adjustment screw 30 is formed distorted near the head end to give a locking action when tightened, thus further preventing the adjustment screw 30 from coming undone once the loading has been adjusted. This may be achieved for example by having an increase in diameter near the head end, or by deforming, that is, burring the thread at this portion.

With such a construction, by providing the protrusion 25 and the adjustment screw formed with the under head portion radiused so as to deform the end rim 32 of the hollow cylindrical portion 26 outwards, the pivotal connection can be kept free and substantially frictionless until assembled with the adjustment screw 30, thus allowing the components to be easily folded for packaging and handling. Moreover the friction 20 attachment can be easily adjusted by simply tightening or loosening the adjustment screw 30.

Here the attachment plates 8, 18, 22 are made from a plastics material with a suitable coefficient of friction to provide the frictional engagement. If desired, a friction material could be fitted for example in the form of an insert or washer between the link 25 arm and the front face of the attachment plates 8, 18, 22 to give greater frictional engagement.

The arrangement shown in FIG. 4 is typical of the arrangement for an adjustable friction attachment device for attachment of the first and second link arms 3 and 12 to the frame 10 or sash 2.

Another adjustable friction attachment device which provides frictional attachment of a pivotal link arm to a sash attachment plate or a frame attachment plate is shown in 9 FIG. 5. In this example components having a similar function to those in FIG. 4 are denoted by the same symbols. The example of FIG. 5 differs from that of FIG. 4 in that a captured nut 34 such as a Riv-nut™ is provided to ensure secure fastening of an adjustment screw 30'. Hence there is no need for the metal nut plate 29, enabling a 5 simpler attachment plate 8'. In this example there is also no need for a special design adjustment screw, and a standard adjustment screw 30' to suit the Riv-nut™ 34 is used. While the underside contour of the head may be different to that of the adjustment screw 30 in FIG. 4, the same effect can be achieved. Moreover using the Riv-nut™ 34 enables the attachment plate to be securely fastened to the frame by the adjustment screw 30' even 10 with low strength frame material.

Yet another adjustable friction attachment device which provides frictional attachment of a pivotal link arm to a sash attachment plate and a frame attachment plate is shown in FIG. 6. In this example components having a similar function to those in FIG. 4 and 5 are denoted by the same symbols. The example of FIG. 6 differs from that of FIG. 4 15 and 5 in that the first attachment plate 8 comprises a modified attachment plate 8". On a rear side thereof there is provided three cylindrical protrusions generally denoted by arrow 35 (only one shown in FIG. 6 which is a cross-section with the other protrusions positioned to the front and rear side of the page) which are adapted for inserting into holes drilled in the window frame 10 (or sash 2) to provide a secure keyed location. As shown 20 in FIG. 6, for each cylindrical protrusion 35, the bottom 36 of the hole formed in the protrusion 35 is of a smaller diameter, to result in expansion of the end when a screw (represented by the adjustment screw 30" in FIG. 6) is threaded therein, to thereby lock the attachment plate 8" in position. In this example the central cylindrical protrusion 35 (the-cross-section protrusion in FIG. 6) also protrudes from the opposite side of the attachment plate 8" as a hollow cylindrical portion 26 to serve as the pivotal connection device, by fitting into the frame pivot bore 6 formed in the end of the first link arm 3.

Here as with the previous examples, the adjustment screw 30" also serves as an attachment means in conjunction with the first attachment plate 8", for attaching the first link arm 3 to an inner peripheral face of a window frame 10 (or the sash 2). Moreover, 30 this method enables attachment to the frame or sash of a window, with a minimum of parts, and avoids metal to metal contact between the adjustment and fastening screws and the aluminium window frame member, which could lead to corrosion, condensation and the like.

As can be understood by reference to FIG. 6, once the first link arm 3 is fitted to the central cylindrical protrusion 26, the adjustment screw 30" is inserted into the hole and tightened to thereby expand the bottom 36 of the cylindrical protrusion 35 and secure the first attachment plate 8" in position, and also clamp the link arm 3 tight against the face of 5 the attachment plate 8" with the end rim 32 of the cylindrical protrusions 26 expanded outwards to assist in providing a frictional engagement. Moreover, fastening screws are also screwed into the other cylindrical protrusions 26 (positioned to the front and rear side of the page in FIG. 6) to additionally secure the attachment plate 8" in a similar manner.

In all of the examples above, the attachment plates 8,18, 22 are formed with a 10 ramp portion 36 (FIG. 2) towards one end thereof. This ramp portion 36 serves as a limit stop to limit pivotal movement of the first link arm 3 to a maximum range shown on the left and right in FIG. 1 (closed condition and open condition respectively). In these examples, the attachment plates 18, 22 for the second link arm 12 do not provide a limit to the pivotal movement of the second link arm 12, and hence do not need the ramp portion 15 36. However, by making these attachment plates 18, 22 the same as the attachment plates 8, 22 of the first link arm 3, the number of different components can be minimised.

As will be apparent from the configuration of the embodiment of the invention, the window is supported by the two link arms 3 and 12. The first link arm 3 is provided with the friction attachment device 20 at at least the window frame end, while the second link 20 arm 12 is provided with the friction attachment device 20 at both ends. Hence the window can be reliably supported in optional open positions.

Moreover, since the loading of the friction attachment devices 20 can be easily adjusted by tightening or loosening the adjustment screw 30 (30', 30"), the friction bar assembly 1 can be used for supporting and holding various sizes of openable window.

Furthermore, since the location of the attachment plates 8 and 18 on the frame 10 can be altered (optional spacing X), then the opening amount of the window can be optionally set.

Also since the size of the attachment plates 8, 18 and 22 are small, compared to conventional friction bar assemblies which are mounted on an elongate base plate, the 30 attachment device can be easily fitted to window frames of various profiles. 11 With the above configuration where the location of the attachment plates 8 and 18 on the frame 10 can be altered (optional spacing X), then when fitting the friction bar assembly 1, a jig such as the jig plate 40 in FIG. 1 with a predetermined cross section indicated by arrow Z, and with holes 42, 44 and 46 drilled at suitable spacing, may be clamped in position on the frame 10 or the sash 2, and holes drilled in the frame 10 or sash 2 using the holes 42, 44 and 46 for a guide. Here holes 42 and 46 are at spacing X between pivot bores 6 and 16 on the frame 10, and holes 44 and 46 are at the spacing between the pivot bores 4 and 14 on the sash 2. The jig plate 40 may of course have more holes, which can be appropriately selected depending on location requirements for drilling the frame and sash. Moreover, the jig plate 40 may be adjustable, e.g. telescopic, for added versatility.

FIGS. 7 to 10 illustrate a second embodiment of a friction bar assembly according to the present invention generally indicated by arrow 100. The part where this differs from the configuration described above, is that the nut plates 29 are provided as part of an elongate base plate. This configuration has an advantage in that the spacing of the attachment plates 8, 18, 22 can be set without the need for the jig plate 40, and the nut plates 29 can be more reliably fitted to the attachment plates 8, 18, 22 by suitable design of components.

In FIG. 7 to FIG. 10 parts having a similar function to those of the first embodiment are drawn the same and in most cases are denoted by the same reference symbols, and description thereof is omitted.

Hereunder the description focuses on the major difference, being the attachment plate 8 (18, 22) and the elongate base plates 200 and 210.

The elongate base plates 200 and 210, are in effect, in a form with the two nut plates 29 of the first embodiment integrally formed on the ends of an elongate plate.

These nut plate sections are denoted by reference symbol 290 to differentiate over the nut plates 29 of the first embodiment, however parts similar to the nut plates 29 are denoted by the same reference symbols for simplicity of description.

Each nut plate section 290 is press formed on opposite ends of the elongate base plates 200 and 210, and has a flat face on one side continuous with that of the elongate base plates for mounting on a window frame, and two apertures 29' formed therein for 12 accommodating the protrusions 25 on the plate member 24. The other parts are the same as those described for the nut plate 29 of FIG. 3, except that the two holes 29' are surrounded by a counter sunk area 50 described hereunder.

In this embodiment, the plate member 24 of the attachment plates 8,18, 22 is 5 formed with two protrusions 25 (FIG. 9) provided on a rear side of the plate member 24 towards each end for inserting into the apertures 29' formed in the nut plate sections 290.

As shown in FIG. 10, the attachment plate may be assembled as one unit together with the elongate base plates 200 and 210. In this case, the ends of the protrusions 25 are peened over (deformed), once the attachment plates 8, 18, 22 have been fitted to the 10 elongate base plates 200 and 210, to thereby provide the made up assembly. At this time the peened over (deformed) ends are accommodated in the counter sunk area 50 so as not to protrude from the mounting face of the elongate base plates 200 and 210.

Moreover, as shown in FIG. 10, in the assembled condition of the friction bar assembly 100, the adjustment screws 30 are threaded into the threaded portions 31 of the 15 nut plate sections 290, so as to protrude from the mounting face side of the elongate base plate 200, 210. However, in this condition the adjustment screws 30 are not tightened, and hence the friction bar assembly 100 can be easily folded for packing. When ready to install the friction bar assembly, if desired, the adjustment screws 30 and the link arms 3 and 12 may be removed, and the elongate base plates 200, 210 with the attachment plates 20 8, 18, 22 attached thereto, may be positioned on the window frame (or sash) as a jig for marking holes to be drilled. Then the link arms 3 and 12 can be refitted, and the adjustment screws 30 inserted into the holes and tightened to thereby provided the desired friction attachment, and at the same time secure the friction bar assembly 100 in position.

The above descriptions have been for friction bar assemblies having friction 25 attachment devices 20 on both ends of the first link arm 3 and the second link arm 12.

However, the invention is not limited to this configuration and depending on requirements it may be sufficient to have the friction attachment device 20 on only one of the link arms. In this case the pivotal connection at the other end of the link arm may be provided by having a flat head screw and washer so as not to deform the end rim 32 of the cylindrical 30 protrusions 26, and give a minimal clamping load. 13 Moreover, the frame and sash components shown in the figures are shown as aluminium extrusions, however the invention is not limited to this material, and can be applied to openable windows made of other suitable materials such as PVC window extrusions.

Furthermore, the link arms may be made from any suitable material. For example these may be aluminium or stainless steel. Stainless steel may have an advantage in that it does not require powder coating.

We believe the advantages of our invention to be as follows, however it should be appreciated that all such advantages may not be realised on all embodiments of the 10 invention and the following list is given by way of example only as being indicative of potential advantages of the present invention. Furthermore it is not intended that the advantages of the present invention be restricted to those of the list which follows: 1. Since in the first embodiment, the friction bar assembly is provided with separate attachment plates, the assembly can be easily fitted to window frames of various profiles and sizes, thus obviating the need to stock a range of assemblies to suit different window frames. 2. The attachment plates and the friction attachment device components are all similar in design, except that the attachment plates 18 and 22 for the second arm 12 do not necessarily need the ramp 36. Hence the number of different components is reduced compared to conventional friction bar assemblies, thus minimising inventory costs and manufacturing costs. 3. The configuration of the friction bar assembly can be easily changed to suit requirements. For example the number of friction attachment devices can be easily altered. 4. By providing the hollow cylindrical protrusion and the screw formed with the head portion radiused so as to deform the end of the hollow cylindrical portion outwards, the screw head does not contact with the link arm, thus helping to prevent the screw coming undone with repeated pivoting of the link arm.

. Using the metal nut plate together with the attachment plate provides a metal 30 thread section for the attachment plate to ensure secure fastening of the adjustment screw. 14 6. The method of attaching the attachment plate by using the riv-nut™ enables the attachment plate to be securely fastened to the frame by the adjustment screw even with low strength frame material. 7. The method of attaching the attachment plates by using a screw to expand the 5 locating protrusions, enables attachment to the frame or sash of a window, with a minimum of parts, and avoids metal to metal contact between the adjustment and fastening screws and the aluminium window frame member, which could lead to corrosion, condensation etc. 8. In the first embodiment, the opening range of an openable window assembly can 10 be easily altered to suit requirements by simply changing the position of attaching the attachment plate or pivot pin (adjustment screw 30) to the frame or sash and/or simply fitting a different length link arm. 9. Since the adjustment screw 30 is fixed direct to the sash or frame, loading can be transmitted directly to the frame or sash giving greater rigidity and security compared to with a conventional friction bar assembly which is attached via a base plate.

. The adjustable friction attachment device gives longer usable life and allows for different weighted sashes and sizes. 11. The long link arm (second link arm 12) can be fixed at the bottom of the window frame to restrict the opening of the window and thus eliminates the need for a restrictor stay. 12. In the first embodiment, by providing the elongate base plate with the nut plate sections at each end, the assembly can be made to a required configuration as a complete assembly, thus facilitating installation. Moreover, since there is no friction at the connection between the members prior to fitting, the assembly can be easily folded for packing.

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope of the invention as defined in the appended claims.

Claims (21)

15 What we claim:

1. A friction bar assembly for supporting and holding an openable window in an optional opened position, comprising: a first link arm having a sash pivotal connection bore and a frame pivotal 5 connection bore at opposite ends thereof; first attachment means adapted for attaching said first link arm to an inner peripheral face of a window frame through said frame pivotal connection bore,; a second link arm having a sash pivotal connection bore and a frame pivotal connection bore at opposite ends thereof; 10 second attachment means adapted for attaching said second link arm to an inner peripheral face of the window frame through said frame pivotal connection bore; and friction attachment means for providing frictional attachment between at least one of said link arms and said attachment means, wherein at least one of said first and second attachment means comprises an 15 attachment plate having a hollow cylindrical protrusion on one side thereof, with an outside diameter to allow a sliding fit inside said pivotal connection bore, and said friction means comprises in combination, said hollow cylindrical protrusion and a screw having a threaded end adapted for screwing into said frame or a member attached to said frame, and a head formed with a radiused face on an inside 20 thereof, so as to deform an end rim of said hollow cylindrical portion outwards when tightened, and thereby provide a frictional attachment between said link arm and said attachment plate.

2. A friction bar assembly according to claim 1, wherein said radiused face of said screw is such that when tightened against said end rim, said screw head has substantially 25 no contact with said link arm.

3. A friction bar assembly according to either one of claim 1 and claim 2, further comprising a nut plate provided with a thread to take the thread of said screw, and said nut plate comprises a flat section and a protruding cylindrical section, said protruding cylindrical section being provided with said thread, and having an outside diameter to 30 allow fitting inside the bore of said cylindrical portion of said attachment plate. 16

4. A friction bar assembly according to any one of claim 1 through claim 3, wherein the thread of said screw is distorted to give a locking action when tightened.

5. A friction bar assembly according any one of claim 1 through claim 4, wherein said attachment plate comprises one or more protrusions on a rear side thereof with an axis 5 spaced apart from an axis of said hollow cylindrical portion.

6. A friction bar assembly according any one of claim 1 through claim 5, further comprising a nut plate having a flat face on one side for mounting on a window frame and at least one hole formed therein for accommodating said protrusion of said attachment plate, and a cylindrical threaded portion protruding from an opposite side thereof and 10 adapted for insertion into said hollow cylindrical portion, to provide a metal thread on the inside.

7. A friction bar assembly according claim 6, wherein said nut plate further has a raised section surrounding said cylindrical threaded portion for fitting into a recess formed in said attachment plate. 15

8. A friction bar assembly according either one of claim 6 and claim 7, wherein said nut plate is provided at each end of an elongate base plate and integral therewith.

9. A friction bar assembly according any one of claim 1 through claim 5, wherein said attachment plate further comprises a rear face hollow cylindrical portion on an opposite side of said attachment plate and coaxial with said hollow cylindrical portion to 20 form an aperture through said attachment plate, and said screw is adapted for threading into said rear face hollow cylindrical portion, the internal diameter of said rear face hollow cylindrical portion being set so as to provided suitable expansion of said cylindrical portion when threaded by said screw to thereby lock said attachment plate to said frame.

10. A friction bar assembly according any one of claim 1 through claim 9, further 25 comprising third and fourth attachment means of a similar construction to said first and second attachment means.

11. An attachment plate for a friction bar assembly comprising a hollow cylindrical protrusion on one side thereof, with an outside diameter to allow a sliding fit inside a pivotal connection bore of a link arm of a friction bar assembly having a sash pivotal 30 connection bore and a frame pivotal connection bore at opposite ends thereof. 17 15 0 20 25

12. An attachment plate according to claim 11, connected by connection means to a nut plate provided with a thread to take a thread of a screw, said nut plate comprising a flat section and a protruding cylindrical section, said protruding cylindrical section being provided with said thread, and with an outside diameter to allow fitting inside the bore of said cylindrical portion of said attachment plate.

13. An attachment plate according to claim 12, wherein said connection means comprises a protrusion on a face of said attachment plate which is fitted into a hole on said nut plate and is peened over (deformed) to secure said attachment plate to said nut plate.

14. An attachment plate according to either one of claim 12 and claim 13, wherein said nut plate is formed integral with an elongate base plate.

15. A method of providing a support for an openable window, involving fitting a friction bar assembly according to any one of claim 1 through claim 7 to a window sash and a window frame.

16. A method according to claim 15, comprising, when fitting said friction bar assembly, clamping a jig plate with holes drilled at suitable spacing, in position on the frame or sash, and drilling holes in the frame or sash using the jig plate holes for a guide.

17. A method of providing a support for an openable window, involving fitting a friction bar assembly according to claim 8 to a window sash and a window frame.

18. A method according to claim 17, comprising, when fitting said friction bar assembly, using said elongate base plate as a guide for drilling holes in the frame or sash.

19. An attachment plate for a friction bar assembly substantially as described herein with reference to the appended drawings.

20. A friction bar assembly substantially as described herein with reference to the appended drawings.

21. A method of providing a support for an openable window substantially as described herein with reference to the appended drawings. M. J. SERVICE Attorneys for: Aluminium Syst< END OF CLAIMS A window friction bar assembly (100) comprises: first and second link arms (3, 12) which have pivot bores (4, 6, 14, 16) at each end, and first and second attachment plates (8, 18) for attaching the first and second link arms (3, 12) to a window frame through the pivot bores (6, 16). At least one of the attachment plates (8, 18) constitutes a friction attachment device (20), having a hollow cylindrical protrusion (26) on one side, with an outside diameter to allow a sliding fit inside the pivot bore (6, 16). A screw 30 adapted for screwing into the window frame, has a head formed with a radiused face on an inside, so as to expand an end rim (32) of the hollow cylindrical protrusion (26) when tightened, and thereby provide a frictional attachment between the link arm (3, 12) and the attachment plates (8, 18).