GB2102052A - Framed window unit - Google Patents

Abstract

In a framed window unit, the metal frame 12 which carries the glass G is itself carried by a non- metallic frame 11 secured, in use, to a wall or other surface of a building. The frames 11, 12 are so sized and shaped that, when in position against one another, the back face of the aluminium frame 12 overlaps the front face of the timber frame 11. A soft resilient bead or gasket 13 insulates the glass G from the glass-carrying aluminium frame 12, and that bead or gasket 13 extends over at least the bottom free edge of the back face of the frame 12 to compress resiliently against the front face of the timber frame 11. The timber frame and resilient sealing extension provide an effective internal condensation inhibitor and the sealing bead or gasket can be specially configured to allow any internal condensation to be collected and drained-down through the bottom rail of the aluminium frame 12 and onto an external sill 15. The sealing extension may flex resiliently in an arc curving, from root to tip, away from the central region of the window. The resiliently deformable curving portion may be tubular in cross-section. External air pressure then tend to tighten the seal between the frames. <IMAGE>

Description

SPECIFICATION Framed window unit The invention relates to framed window units.

Domestic framed window units are traditionally timber-framed, because timber has always been cheap and, until recent times, relatively plentiful.

Timber-framed units are now gradually being replaced by units in which the glass is carried in a metal frame. The usual metal used is aluminium, which is light in weight, does not have to be painted, and resists attack from hostile weather elements far better than does timber. If timber is used at all in such constructions, it is only as a hidden subframe which is fixed to the wall of the building and supports the aluminium frame whilst being completely covered by it.

Aluminium-framed window units have one continuing problem: condensation tends to form on the back face (i.e. the surface facing into the building) of the aluminium frame if, as is almost always the case, the temperature inside the building is noticeably higher than the temperature outside. The condensation can drain off the frame and down the inside wall. This problem is well recognised, and several attempted solutions have been put forward. Most of the these centre around trying to create a so-called 'thermal break' between the glass and the back face of the aluminium frame. These attempts have met with varying degrees of success. At best, they still do not inhibit frame condensation fully, and they are expensive.They also leave the back face of the aluminium frame exposed to view within the building, and some people find that this detracts from the visual appeal of the window and the room of which it forms part.

According to the invention, in a framed window unit which, in use, may form part of a building, the metal frame which carries the glass ('the front frame') is itself carried by a non-metallic frame ('the back frame') secured, in use, to a wall or other surface of the building; the two frames are so sized and shaped that, when in position against one another, the back face of the metal frame overlaps the front face of the non-metallic frame; and a non-metallic bead or gasket insulates the glass from the glass-carrying frame and extends over at least the bottom free edge of the back face of that frame to compress resiliently, in use, against the front face of the non-metallic frame.

The inventive concept can be applied to windows which are permanently closed and to windows which are openable. It enables a builder to construct the walls of his building initially using standard timber frames, with which he is familiar, and then to buy from stock a series of glasscarrying aluminium frames which already incorporate the extension-seal and which can be secured to the installed timber frames to seal against them. The timber frame and sealing extension provide an effective internal condensation inhibitor without the need for the elaborate 'thermal break' construction reviewed above. The appearance of the internally-facing timber surfaces is also more attractive than that of an aluminium back frame.

Practical embodiments of the invention, described and illustrated in this specification, have been developed with the use of timber back frames and aluminium front frames in mind.

Within its broadest aspect, however, the invention is not limited to these materials for the two frames or, indeed, to glass panes for the so-called 'glass'.

In one special configuration of the extensionseal, the bead or gasket extension flexes resiliently in an arc between the back face of the metal frame and the front face of the non-metallic frame, and the arc curves, from root to tip, away from the central region of the window.

Any air pressure from outside tends only to tighten the seal by flexing it more firmly against the front race of the non-metallic back frame.

The seal, in the region between the two frames, may incorporate a resiliently deformable portion which in cross-section is tubular. With the frames in position against one another, the tubular portion will be squashed and can form a very effective seal against outside draughts.

The resiliently deformable tubular portion may for example be constituted by a flexing arc form which, when compressed between the two frames, assumes a tubular cross-section. Such an arc, forming the sealing extension required by the broadest aspect of the invention, could constitute the sole sealing means between the two frames.

Preferably however the resiliently deformable tubular portion, whether wholly tubular or whether constituted by a flexing arc, is shielded from outside air pressure by a flexing arc form curving, from root to tip, and from the front frame to the back frame, away from the central region of the window.

Framed window units embodying the invention are illustrated, by way of example only, in the accompanying drawings. They will now be described with reference to those drawings. They each consist of a timber back frame carrying an aluminium glass-carrying front frame. They are designed to be installed as original units in newlyconstructed buildings.

In the drawings: Figure 1 shows a butt-jointed unit viewed from the front; Figures 1 A1,1 A2 and 1 A3 are respectively sections along the lines 1-1, 2-2 and 3-3 of Figure 1; Figures 1 by, 1 B2 show a similar unit; Figure 1 A4 shows the precise cross-section of the glazing and sealing gasket of the Figure 1-type unit; Figure 2 shows a mitre-jointed unit viewed from the front; Figures 2A1, 2A2 and 2A3 are sections along the respective lines 1-1, 2-2 and 3-3 of Figure 2; Figures 2B1, 2B2 shows a similar unit; Figure 2A4 shows the precise cross-section of the glazing and sealing gasket of the Figure 2-type unit; and Figure 3 shows another unit in cross-section.

Referring initially to Figure 1, and the group of Figures associated with it, a framed window unit is rectangular in overall shape and consists of two frames, a timber frame 1 1 supporting an aluminium frame 12. The aluminium frame is the glass-carrying frame, and is double-glazed with factory-sealed panes 'G'. The panes G are insulated from the surrounding aluminium frame 12 by resilient rubber gaskets 13. The gaskets are shown only in approximate form in all except Figure 1 A4 of this first group of drawing Figures.

The aluminium frame 12 is the front frame of the unit. It is exposed to outside weather conditions when fitted in position on the external wall of the building of which the two-frame unit forms part. The timber frame 1 1 constitutes the back frame of the unit. It is largely protected by the aluminium frame 12 and its surrounding aluminium head and sill strips 14, 15 from the weather.

The aluminium head and sill strips 14, 15 are screwed directly to the front faces of the respective top and bottom rails of the timber frame 1 as indicated at, respectively, 1 4A and 1 so. An elongate hard plastics strip 1 4B is screwed to the underside of the top surface of the aluminium head strip 14. It prevents the glass carrying aluminium frame 12 from being inadvertently swung completely off its hinge.

Respective plastics end plugs 1 SB are pushfitted into either end of the aluminium sill.

The aluminium glass-carrying frame 12 is buttjointed. Its top rail 1 2A has an integrally-formed forward-projecting extension, referenced 16, which pivots about a similarly elongate upturned bead 17 on the head strip 14 to allow the glasscarrying frame 12 to be opened and closed about its top edge. Its bottom rail 1 2B is turned outwardly to provide drainage from the front of the window onto the sill 15.

The top and bottom rails 1 2A, 1 2B each have respective screw-receiving extrusions 'S'. The two opposite side rails 1 2C of the units are held to the top and bottom rails by self-tapping screws which engage in the bores of the screw-receiving extrusions S. Internally-mounted window fittings (not shown in the drawings) hold the window closed and prevent it from being opened from outside. Their design can readily be evolved by the man skilled in this field, or they can be selected from known alternatives.

The timber frame 1 1 is installed into the surrounding brickwork of the wall or other surface of the building using known techniques. When the aluminium head and sill strips 14, 15 have been screwed to the timber frame 1 , the gaps between those strips and the surrounding brickwork can be filled in as indicated in the drawings. As Figure 1 shows, only two relatively narrow opposite upright strips of the timber frame 1 1 are visible from the front of the completed window unit.

The two frames 1 1, 12 are so sized and shaped that, when in position against one another, the back face of the front frame 12 overlaps the front face of the back frame 1 1.

The precise form of the rubber sealing gaskets 13 is shown in Figure 1A4. It is shown only diagrammatically in the remaining Figures. The gaskets 13 insulate the glass G from the surrounding aluminium framework. They are continued integrally over the free edges (i.e. the edges at each extremity of the U cross-section of each aluminium frame rail) of the back face of the aluminium frame 12, to curve in an arc, from root to tip, away from the central region of the window, bearing against the front face of the timber frame 1 1 as indicated at 1 8 in Figure 1A4; curving back to bear again against the back face of the aluminium frame 12 as indicated at 19 in Figure 1 A4 and so defining, effectively, a resiliently deformable elongate tubular seal between the two frames; and finally curving out again, in the same direction as the first part of their initial curve, to flex in an arc against the front face of the timber frame 1 1 as indicated in Figure 1 A4 at 21.

These resiliently deformable rubber gaskets, with their integrally formed sealing extensions, continue around the entire periphery of the back face of the aluminium frame 12.

Where the gasket extends over the free edges of the back face of the frame 12, it is dished, as indicated at 22, to collect an condensation which might, in use, form on the internal window surfaces. Such condensation can easily be wiped up from the dished portion 22 of the gasket running along the back face of the bottom rail 1 2B of the frame 12. Until it is wiped up, it simply lies in the dished region of the gasket extension, against the glass G, without necessarily draining onto the bottom rail of the timber frame 1 1.

The bottom-rail gasket extension could be slotted, in its dished region 22, to allow condensation to drain through into the base of the U-sectioned aluminium bottom rail 1 2B; and 'weep-holes' drilled at intervals along the base of that rail so that the condensation could then drain out onto the sill 15. Pile strips, to prevent updraught through these drainage holes, could be held at appropriate locations in the bottom rail.

Because a gap is deliberately left between the timber frame and the aluminium frame, the gasket-extension-seals in the gap are subject to excess air pressure from outside. Because of the way the gasket extensions curve, such excess air pressure tends to tighten the seal by flexing the gasket extensions more firmly against the facing surfaces of the two frames.

The two alternative window units illustrated in, respectively, Figures 1A1 etc., and Figures 1 B1 etc., are each 'top-hung'. In other words, they open by pivoting about their top horizontal edge.

The Figure 1 Al version can pivot virtually 900 from its closed position. The Figure 1 B1 version can pivot only approximately 500 from that position. Corresponding parts of the two constructions have been given the same reference numerals, and identical descriptions apply to them. They both exhibit the same frontal appearance, shown in Figure 1. They also both look identical when viewed on the line 3-3 of Figure 1, and so the Figure 1 B3 which would correspond to Figure 1 A3 has been omitted as unnecessary.

The two constructions shown in Figures 2A1 etc., and 2B1 etc., are very similar to those described in detail above and illustrated in Figures 1 awl, 1 B1. One difference is that the aluminium glass-carrying frames of the second pair of units are mitred rather than being butt-jointed. The difference in frontal appearance is shown in Figure 2, and the necessary differences in the cross-sectional appearance of the extruded aluminium frame rails (in particular the two rails 1 2C) will be apparent from the remaining Figures.

Corresponding parts have again been given the same reference numerals as in the previous Figures, and once again there is no Figure 2B3 because it would be identical to Figure 2A3.

The other major difference between this second pair of embodiments of the invention, and the pair described in detail above, lies in the precise form of the gasket 13. It can be seen from Figure 2A4 that a double-seal is again used, but both parts of the gasket sealing extension are constituted by resiliently flexible curving arc forms which, unlike the extension shown in Figure 1 A4, can flex independently of one another. It will also be noted that the inner of these two arcs, when compressed between the two frames 1 1, 12, tends to close into a tubular cross-section.

In Figure 3 an aluminium front frame is again carried on a timber back frame installed in the wall of a building. The front frame is double-glazed, but instead of a gasket the construction uses two beads to hold the glass panes in place. Both beads are carried in legs which are formed in the aluminium rail extrusions.

The external bead 1 3A is made of resilient plastics or rubber material. The internal bead 1 3B is made of similar material, although it could be slightly softer or could be made of dual-hardness material being harder in the region where it is located in the frame rail and softer in its extension region. The extension region of the inner bead 1 3B covers the bottom free edge of the bottom rail of the glass-carrying frame and flexes resiliently in an arc against the front face of the timber frame as in the previous embodiments.

The form of the internal glazing and sealing bead 1 3B is shown only approximately in Figure 3.

The bead extension can take any of the forms illustrated and described with respect to any of the other embodiments. The top surface of the extension 1 3B is dished as in the previous embodiments to collect condensation. It could also be drilled or slotted, as previously outlined in connection with the other embodiments, to allow condensation to drain down into the base of the aluminium bottom rail and then out through holes in that rail onto the outside surface of the aluminium sill.

The other constructional details of the Figure 3 embodiment are broadly similar to those of the previous embodiments and have been given corresponding reference numbers. As the two beads 1 3A, 1 3B do not extend entirely around the double-glazed unit, some form of resilient pad will of course be provided to cushion the periphery of the unit and complement the action of the two beads 1 3A, 1 3B which locate the unit laterally in the frame.

One advantage of the beaded, rather than gasketed, construction of Figure 3 is that the aluminium glass-carrying frame can be screwed together around the double-glazed unit and with the internal glazing and sealing bead 1 3B already installed around the inside periphery of the frame; the frame can be trued up and screwed tight; and only then need the external beading 1 3A be driven home to secure the double-glazed unit in place in the frame without distorting the frame. By comparison, the previously described gasketglazed embodiments have to be trued-up in a single final screw-tightening operation with the glass and the gasket already in place and with no means of final adjustment of the gasket fit possible.

In Figure 3, the top hinge of the unit is located farther in with respect to the glass-carrying frame than was the case in the previous embodiments.

This is advantageous because the window tends to stay shut under gravity whereas in the previous embodiments it would tend to swing slightly open.

In general if the hinge axis is behind the centre of gravity of the glass-carrying framed unit, the window will stay shut under gravity rather than swinging open.

To improve the appearance of the assembled and installed window unit, the two vertical timber strips which are visible when the window is viewed from the front could be covered. For example they could be each covered by a respective elongate plastics strip, "fir-treed'd" into a sawgroove in the front surface of the timber.

Such a strip could have an extension to its laterally outer edge which flexes arcuately against the brickwork abutting the timber frame and which takes the place of the conventional mastic weatherproofing seal between frame and brickwork. The strip when incorporating such an extension could be extruded in so-called "dualdurometer" form, i.e. with the flexing extension composed of softer material than the body of the strip. The extension could be of any suitable form illustrated and described herein when referring to the sealing bead and gasket extensions.

Claims (12)

1. A framed window unit in which the frame which carries the glass ('the front frame') is itself carried by a non-metallic frame ('the back frame') secured, in use, to a wall or other surface of the building; the two frames are so sized and shaped that, when in position against one another, the back face of the metal frame overlaps the front face of the non-metallic frame; and a non-metallic bead or gasket insulated the glass from the glasscarrying frame and extends over at least the bottom free edge of the back face of that frame to compress resiliently, in use, against the front face of the non-metallic frame.

2. A window unit according to Claim 1 in which the bottom-back-edge-covering region of the sealing bead or gasket extension incorporates a trough into which any internal condensation will drain.

3. A window unit according to Claim 1 or Claim 2 in which the bottom-back-edge-covering region of the extension is perforated to allow internal condensation to drain down onto the bottom rail of the glass-carrying frame.

4. A window unit according to Claim 3 in which the bottom rail itself is perforated to allow condensation draining onto or into the bottom rail to find its way onto an external surface of the unit or of the building surface in which the unit is fixed.

5. A window unit according to any of the previous Claims and in which the sealing extension flexes resiliently in an arc between the back face of the front frame and the front face of the back frame, and the arc curves, from root to tip, away from the central region of the window.

6. A window unit according to any of the previous Claims and in which the sealing extension, in the region between the two frames, incorporates a resiliently deformable portion which in cross-section is tubular.

7. A window unit according to Claim 6 and in which the resiliently deformable tubular portion is constituted by a flexing arc form which, when compressed between the two frames, defines with one of the frame surfaces a tubular cross-section.

8. A window unit according to any of the previous Claims and in which the glass is held in the glass-carrying front frame between respective front and back beads, the back bead having the bottom-back-edge-covering window-sealing extension.

9. A window unit according to any of the previous Claims and in which the front frame overlaps but does not wholly overlie the back frame, and the non-overlaid front surfaces of the back frame which would otherwise be left visible are covered by a strip which abuts the edge of the wall or other surface in which the back frame is secured.

10. A window unit according to Claim 9 in which the or each such strip flexes resiliently against the abutting wall or other surface material.

1 1. A framed window unit substantially as described herein with reference to and as illustrated by any of the embodiments shown in the accompanying drawings.

12. Means, relating to an essential element of the invention, suitable for putting or intended to put into effect the invention defined in any of the previous Claims.