GB2073290A

GB2073290A - Thermally insulating windows

Info

Publication number: GB2073290A
Application number: GB8011197A
Authority: GB
Original assignee: Sapa AB; Skandinaviska Aluminium Profiler AB
Current assignee: Hydro Extruded Solutions AB
Priority date: 1980-04-03
Filing date: 1980-04-03
Publication date: 1981-10-14

Abstract

A glazing unit (34) is supported on an extrusion (52) of aluminium. The interior surface of the aluminium extrusion is totally surrounded by a co-extruded PVC extrusion (74) which defines a cavity filled with foam (76). A second extrusion (54) of aluminium is snapped in position to retain the triple glazed unit (34). This inner window assembly is pivotally mounted on an outer frame (30) comprising aluminium extrusion (36) provided with an inner coating constituted by a co-extruded PVC member (46) defining a foam filled cavity (48). <IMAGE>

Description

SPECIFICATION Improvements in or relating to thermally insulating windows THE PRESENT INVENTION relates to thermally insulating windows.

It has been known for many years that the thermal insulating properties of a window may be significantly improved by providing the window with two or three parallel spaced sheets of glass instead of utilising a single sheet of glass. Such glazing is known as double or triple glazing. The spacing between the parallel sheets of glass may be at least partially evacuated to improve the thermal insulating properties of the window.

Many prior proposed thermally insulating windows of the double or triple glazed type have been proposed previously. Some of these prior proposed windows utilise frames that are formed entirely of metal, such as extruded anodized aluminium. Aluminium is preferred since it is not necessary to maintain frames of this material, and the frames are not subjected to deterioration by rotting or rusting. Thermally insulating windows of this type suffer from the disadvantage that the aluminium frame forms an excellent thermal conductor and thus, when the ambient temperature on the exterior of such a window falls, the exterior of the frame falls to the low temperature and heat is thus conducted from the portion of the frame on the interior of the building to which the window is fitted.Thus the temperature of the interior portion of the frame may be relatively low, leading to problems of condensation.

In an attempt to obviate this particular problem it has been proposed to provide a double or triple glazing unit including separate interior and exterior frames that are formed substantially of aluminium, the frames additionally including elements of a thermally insulating material which are disposed to provide a thermal barrier between the interior frame and the exterior frame, whilst securing the frames together.

in the accompanying drawings Fig. 1 is a vertical cross sectional view of one typical prior proposed insulating window of the above described type. The illustrated window has an outer frame 2 which comprises an interior aluminium extrusion 4 and an exterior aluminium extrusion 6, the outer frame 2 being sealed to a wall or window opening 8 by an appropriate seal 10. The interior extrusion 4 and exterior extrusion 6 are connected together by two elements 12 of thermally insulating material such as the plastics material sold under the Registered Trade Mark "Bakel ite". The interior extrusion 4 and exterior extrusion 6 also support a resilient seal 14.

Mounted within a central aperture formed by the outer frame 2 is a glazed unit 16 which comprises a peripheral frame, the frame comprising an interior aluminium extrusion 18 and an exterior aluminium extrusion 20, these extrusions being interconnected by thermally insulating members 22, such as members made from the plastics material sold under the Registered Trade Mark Bakelite". The extrusions 18 and 20 support, by means of an appropriate seal 24 glazing 26 comprising three sheets of glass maintained in spaced parallelism by appropriate peripheral blocks, the exterior peripheries of the sheets being sealed. The glazed unit 16 is movably mounted with reference to the exterior frame 2 and is thus for example, hinged or pivoted.

The seals 14 between the exterior frame 2 and the triple glazed unit 16 are made of a material that is resilient so that an effective seal is provided which prevents drafts. Thus the seals 14 are of a material that does not necessarily have excellent thermal insulating properties and consequently it is possible for heat to be transmitted from the interior of the frame to the exterior as indicated by the arrow 26. This can lead to undesirable condensation forming on the interior extrusion of the frame.

A further disadvantage of such windows is that the frame visible from the interior of the building is of metal, which has a "cold" appearance.

It has also been proposed to provide thermally insulating windows of the double or triple glazed type where the frames are formed substantially of extrusions of a plastics material, such as extruded polyvinyl chloride (PVC). if the extrusions are provided with voids the frames may be provided with reinforcing members, comprising extrusions of aluminium or members of steel located within the voids. A frame formed of plastics material in this way has the advantage that the plastics material is a poor conductor of heat and thus the frame acts as a thermal insulator. Of course, the aluminium or steel reinforcing sections, if any, are located entirely within voids defined within the frame and thus do not effectively contribute to the conduction of heat across the frame.Whilst the portion of the frame visible from the interior of the building is of plastics material, and thus has a "warm" apperance, one disadvantage associated with the use of such plastics material frame is that the plastics material tends to deteriorate when exposed to sunlight and the weather. Thus the colour inherent in the piastics material tends to fade, at least in the regions of the frame which are subjected to sunlight and weather and thus eventually the frames have an unpleasant appearance.

Additionally it has been proposed to provide frames which comprise elongate extrusions of aluminium which are totally embedded in an extruded member formed primarily of foamed plastics material. Thus the aluminium and the plastics material may be co-extruded when the plastics material is foamed polyvinyl chloride (PVC), although alternatively the plastics material may be cast around a core of aluminium when the plastics material is foamed polyurethane. In frames of this type a single member of foamed plastics material extends from the interior of the frame to the exterior of the frame. A frame of this type suffers from several disadvantages. Firstly it is difficult to provide appropriate corners on such a frame, since the corners are normally provided by utilising a "L" shaped corner piece the arms of which are inserted into elongate cavities formed in the frame members.Of course the frame members are appropriately mitred. In a frame member where the elongate recess to receive an arm of the "L" shaped member is totally surrounded by a foamed plastics material it is virtually impossible firmly to secure the arm of the "L" shaped member in position within the channel. Also, with such frames, it is difficult to mount hinges and other such fixtures on the frames. When the plastics material is foamed polyurethane, whilst the insulating properties of the window may be good, the frames are expensive to produce, since expensive moulds must be used. Also it has only been found practicable to use polyurethane to make frames that are brown in colour. It is also believed that polyurethane will deteriorate when exposed to sunlight and the weather.Whilst the frames utilising polyvinyl chloride may be manufactured more cheaply, such frames also deteriorate when exposed to the weather.

The present invention seeks to provide an improved frame in which the disadvantages and drawbacks of the above described prior proposed frames are obviated or reduced.

It is to be noted that in all the above described frames there is either metal, such as anodized aluminium, exposed on both the interior and the exterior of the frame, or there is a plastic material exposed on both the inside and outside of the frame. It has been found that anodized aluminium is acceptable in that the exterior of frames formed on this material have an aesthetically pleasing appearance, are stable and are maintenance free.

However, frames formed solely of this material are not totally satisfactory in that they transfer heat and have a "cold" interior appearance.

In contrast it has been found that frames formed from a plastics material are acceptable in that the interior of frames formed from such a material may have a "warm" appearance, but sunch frames have the disadvantage that the exterior of such frames may deteriorate when exposed to sunlight and weather.

According to the broadest aspect of this invention there is provided a thermally insulating window assembly said window assembly comprising a glazing unit formed from a plurality of panes of glass located in spaced parallelism, and a peripheral frame, said frame comprising an assembly constituted by at least one metal extrusion and a thermally insulating member, the metal extrusion being located on the side of the window assembly to be located on the exterior of the building in which the assembly is fitted, and the thermally insulating member being located on the side of the window assembly to be located on the interior of the building in which the assembly is fitted.

Preferably the insulating member comprises a body of foamed plastics material having an exterior skin of plastics material. The foamed plastics material and the exterior skin may be formed from polyvinyl chloride, and the foam plastics material and skin may be extruded simultaneously with the extrusion of said metal extrusion.

The exterior skin of the insulating member may have an appearance corresponding to that of wood, the metal extrusions are preferably of aluminium or aluminium alloy, and advantageously at least the surfaces of the aluminium to be exposed on the exterior of the building are anodised.

In one embodiment of the invention the window assembly comprises a hinged or movable window assembly, there being a peripherally outer frame to be mounted securely to the building and an inner frame that is pivotally connected to the outer frame, the inner frame supporting the glazing unit, both the inner and outer frames each respectively being constituted by at least one metal extrusion and a thermally insulating member, the metal extrusion being located on the exterior of the building in which the assembly is fitted and the thermally insulating member being located on the side of the window assembly to be located on the interior of the building in which the assembly is fitted.

Preferably seals are provided between the said outer frame and said inner frame. One such seal may be formed integrally with the insulating member formed on the inner frame.

Whilst it is conceivable that an embodiment of the invention may be so fabricated that the glazing unit may be mounted on the assembly constituted by the metal extrusion or extrusions and subsequently the insulating member may be mounted in position, it is preferred that the insulating member is firmly mounted on one extrusion, and a second extrusion be provided which may be releasably fastened to the first extrusion, the second extrusion, when in position, serving to retain the glazing unit in position. In such an embodiment the insulating member may be co-extruded with the metal member to provided a very firm bond between the insulating member and the metal member.Thus the insulating member and the thermally insulating member will not tend to separate, even if the metal member is subjetted to thermal expansion and contraction relative to the insulating member.

It is to be appreciated that in an. embodiment of the invention where the glazing unit is mounted on an inner frame and an outer frame is mounted on the building the insulating member formed on the peripheral inner frame may be mounted to contact the insulating member formed on a peripheral outer frame. Preferably also a seal is mounted on the outer frame, sealingly to engage the inner frame when the window is closed.

Preferably the insulating member on the frame supporting the glazing unit supports a seal that engages the glazing unit.

In order that the invention may be more readily understood and so that further features thereof may be appreciated, the invention will now be described by way of example with reference to Fig. 2 of the accompanying drawings which is a cross sectional view through part of a thermally insulated window assembly in accordance with the present invention.

Referring to Fig. 2 of the accompanying drawings a window assembly in accordance with the present invention comprises an outer peripheral frame 30 which is adapted to be mounted in an appropriate aperture formed in the wall for the like and an inner peripheral frame assembly 32 which supports a triple glazing unit 34. The inner peripheral frame 32 is movably, for example hingedly, mounted on the outer peripheral frame 30.

The outer peripheral frame 30 comprises an aluminium extrusion 36. The aluminium extrusion 36 has an exterior face 38 which is intended to be exposed to the weather. At least the face 38 is anodized. The extrusion 36 also includes a box section 40 which may be filled with a thermally insulating material such as foamed plastics. The extrusion 36 has an inner end face 42 which is the portion of the extrusion located closest to the interior of the building and this portion of the extrusion is provided with outwardly directed tangs 44.

A rigid polyvinyl chloride extrusion 46 is coextruded with the aluminium extrusion 36, together with a foamed polyvinyl chloride core 48 which fills the chamber defined between the polyvinyl chloride extrusion 46 and the face 42 of the extrusion 36. Since the plastics material is co-extruded with the aluminium there is a very intimate bond between the plastics and the aluminium and the bond is not broken by the thermal expansion or contraction of the aluminium relative to the plastics material.

The extrusion 36 supports a seal member 50 which engages the interior frame 32 as will be described hereinafter.

The inner peripheral frame 32 comprises two aluminium extrusions, namely a first aluminium extrusion 52 and a second aluminium extrusion 54. The first aluminium extrusion 52 comprises a central box section 56 which has an upper surface 58 which supports the triple glazing unit 34. The extrusion 52 has two protruding arms 60, 62 which are directed towards the exterior of the building in which the window is fitted. The arms 60, 62 support the second extrusion 54 which is snap fitted into position, with arms 64, 66 on the second extrusion 54 snappingly engaging recesses and abutments fromed on the arms 60, 62. The extrusion 54 supports a seal 66 which engages the glazing unit 34.

The extrusion 52 has, on the portion 68 which is located closest to the interior of the building, inwardly directed tangs 70 and an inwardly directed lip 72.

A rigid polyvinyl chloride extrusion 74 is coextruded with the aluminium extrusion 52, together with a foamed polyvinyl core 76 which fills the chamber defined between the polyvinyl chloride extrusion 74 and the portion 68 of the aluminium extrusion 52. The polyvinyl chloride extrusion 74 embraces the extrusion 52 and a part 78 of the polyvinyl chloride extrusion lies between the glazing unit 34 and the portion 58 of the extrusion 52. An upper part of the polyvinyl chloride extrusion 74 supports a seal 80 which engages the glazing unit 34.A lower part of the polyvinyl chloride extrusion 74 which, when the window is in the closed position as shown in Fig. 2 of the accompanying drawings, lies adjacent the polyvinyl chloride extrusion 46, supports an integrally formed seal 82, which is sufficiently thin to be resilient, which engages the polyvinyl chloride extrusion 46 which is formed on the outer frame 30.

A portion 84 of the polyvinyl chloride extrusion 74 is bonded to the underside of the box section 56.

When the window is in the closed position as shown in Fig. 2 the seal 50 engages an appropriately shaped part of the lower surface of the box section 56 of extrusion 52. If desired a further seal between the outer frame 30 and the inner frame 32 may be provided in the channel 86 formed on the extrusion 36.

It is envisaged that the side of the frames on which the aluminium is exposed will be located on the exterior of the building. The exposed surfaces at least of the aluminium will be anodised and thus the exterior of the frames will be stable, weather resistant and maintenance free. The side of the frames on which the polyvinyl chloride extrusions are provided will be located on the interior of the building. The polyvinyl chloride extrusions may have an appearance of wood, or some other "warm" appearance. The aluminum extrusion provide the frame with a strength, and enable fixtures and fittings tobe connected to the frame, and the foam filled polyvinyl chloride extrusions provide the desirable heat insulating properties.If desired the seals 66 and 80 can have the same appearance as the polyvinylchloride extrusions 46, 74, and the seal 80 may be formed integrally with the extrusion 74. On the inside of the window the temperature will be substantially constant, and thus there will be no movement between the seal 80 and the glass.

In assembling the triple glazing unit 34 and the peripherally inner frame 32 firstly the glazing unit 34 is mounted in position on the extrusion 52 and secondly the extrusion 54 is snapped into position.

It is to be noted that in the described embodiment of the invention heat cannot be transmitted from the interior of the building to the exterior through the peripherally outer frame 30 since the aluminium extrusion 36 terminates at the face 42 which supports the tangs 44 and this face is thermally insulated from the interior of the building by the foam filled extrusion 46. Furthermore, up to three seals prevent the ingress of cold draught, namely the seals 50, 82 and that provided in channel 86. Even if a cold draught manages to pass the seal 50, the draught will only be able to act on the extrusions 52 and this extrusion, as has been described above, is thermally isolated from the interior of the building in which the window is fitted.

Since the extrusion 54 is movable to enable the glazing unit 34 to be mounted on the extrusion 52, the foam plastics material 76 and extrusion 74 are preferably very firmly connected to the extrusion 52. Since there is a snap fastening between the extrusion 54 and the extrusion 52 it is possible for the two extrusions to expand, by virtue of thermal expansion to different extents without placing any under strain upon the frame of the window.

Whilst the invention has been described with reference to an embodiment comprising a peripheral outer frame and a peripheral inner frame that is hinged relative to the outer frame it is to be appreciated that the invention may equally be applied to thermally insulating window structures that are permanently closed, and which thus comprise a single frame mounted in an appropriate aperture in a wall and directly supporting a glazing unit.

Claims

1. A thermally insulating window assembly said window assembly comprising a glazing unit formed from a plurality of panes of glass located in spaced parallelism, and a peripheral frame, said frame comprising an assembly constituted by at least one metal extrusion and a thermally insulating member, the metal extrusion being located on the side of the window assembly to be located on the exterior of the building in which the assembly is fitted, and the thermally insulating member being located on the side of the window assembly to be located on the interior of the building in which the assembly is fitted.

2. A window assembly comprising a hinged or movable window assembly, therebeing a peripherally outer frame to be mounted securely to the building and an inner frame that is pivotally connected to the outer frame, the inner frame supporting the glazing unit, both the inner and outer frames each respectively being constituted by at least one metal extrusion and a thermally insulating member, the metal extrusion being located on the exterior of the building in which the assembly is fitted and the thermally insulating member being located on the side of the window assembly to be located on the interior of the building in which the assembly is fitted.

3. A window assembly according to claim 1 or 2 wherein the insulating member comprises a body of foamed plastics material having an exterior skin of plastics material.

4. A window assembly according to claim 3 wherein the foamed plastics material and the exterior skin are formed from polyvinyl chloride.

5. A window assembly according to claim 3 or claim 4 wherein the foam plastics material and skin are extruded simultaneously with the extrusion of said metal extrusion.

6. A window assembly according to claim 3, 4 or 5 wherein the exterior skin of the insulated member has an appearance corresponding to that of wood.

7. A window assembly according to any of the preceding claims wherein the metal extrusions are of aluminium alloy, and at least the surfaces to be exposed on the exterior of the building are anodised.

8. A window assembly according to claim 2 or any claim dependent thereon wherein seals are provided between the said outer frame and said inner frame.

9. A window assembly according to claim 8 wherein one seal is formed integrally with the insulating member formed on the inner frame.

10. A window assembly according to claim 8 or 9 wherein the outer frame, sealingly to engage the inner frame when the window is closed.

11. A window assembly according to any one of the preceding claims wherein the or one insulating member is firmly mounted on one extrusion, and a second extrusion is provided which may be releasably fastened to the first extrusion, the second extrusion, when in position, serving to retain the glazing unit in position.

12. A window assembly according to claim 11 wherein the insulating member is coextruded with the metal member to provide a very firm bond between the insulating member and the metal member.

13. A window assembly according to claim 2 or any claim dependent thereon wherein the insulating member formed on the peripheral inner frame is mounted to contact the insulating member formed on a peripheral outer frame.

14. A window assembly according to any one of the preceding claims wherein the insulating member on the frame supporting the glazing unit supports a seal that engages the glazing unit.

15. A window assembly substantially as herein described with reference to and as shown in the accompanying drawings.

16. Any novel feature or combination of features disclosed herein.