WO1996033334A1

WO1996033334A1 - Glazed window unit

Info

Publication number: WO1996033334A1
Application number: PCT/GB1996/000957
Authority: WO
Inventors: Paul Stephen Ennis
Original assignee: Paul Stephen Ennis
Priority date: 1995-04-21
Filing date: 1996-04-22
Publication date: 1996-10-24
Also published as: GB9508192D0; AU5342996A

Abstract

A central layer (16) comprising a sheet of indestructible translucent plastics material is mounted between inner and outer layers (12, 14) both of glass, without any direct bonding therebetween. By means of spacers (18, 20), gaps may be provided between the central layer (16) and the respective inner and outer layers (12, 14) so as to provide a triple glazed unit with enhanced security. Alternatively, no gaps may be provided, the central layer (16) being directly sandwiched between the inner and outer layers (12, 14), in the cavity defined by the spacers, which are then disposed between the inner and outer layers (12, 14).

Description

Glazed Window Unit

This invention concerns a glazed window unit. In particular, though not exclusively, the invention relates to a triple glazed security window unit which can also be an insulating window unit.

Triple glazed insulating units comprising three sheets of glass with spaces therebetween are, of course, well known for their enhanced thermal and sound insulation properties compared to single sheets of glass or conventional double glazed units. Also known are various laminates of glass or of glass and plastics, usually resins, which are thicker and stronger than plain glass sheets and afford a measure of resistance to attack and breakage.

An object of the present invention is to provide a particular construction of glazed window unit having enhanced attack resistance properties and, optimally, enhanced sound and thermal insulation properties.

According to the invention a glazed window unit consists of three layers, namely a central layer comprising a glazed window unit consisting of three layers, namely a central layer comprising a sheet of shatterproof translucent plastics material, and an outer layer and inner layer, both of glass, the central layer being mounted between the inner and outer layers but not being directly bonded to either of them.

The central layer may consist of a single sheet of plastics material and suitable materials are polycarbonate resins, acrylic resins, vinyl chloride resins and styrene resins. A particularly preferred material is a polycarbonate resin which is commercially available under the registered trade mark "LEXAN". When made of the preferred material, the central layer is totally unbreakable and will withstand any form of physical attack.

A suitable thickness for the central layer is in the range 2mm to 10mm, a preferred thickness being about 6mm.

The inner and outer layers may consist of single sheets of glass of any type, such as laminated glass, float glass or toughened glass. Preferably, however, at least one (or may be both) of the inner and outer layers consists of glass laminate of two or three or more leaves bonded together. Suitable thickness for the inner and outer layers are between 2 mm and 12 mm if single sheets, or between 6.4 mm and 11.5 mm when laminated glass is used. In triple glazed embodiments in accordance with the present invention there are gaps between the inner and central layers and the central and outer layers, respectively, and these gaps are conveniently in the range of 3 to 24 mm, most suitably about 6 mm. During production of such a window unit, the three layers are assembled with spacer material, eg spacer bars, adjacent the edges of the layers to hold the inner and outer layers apart from the central layer by the selected gap distance. A bonding agent is provided on both faces of the spacer material to form a primary seal between the respective adjacent layers.

Alternatively, particularly if a small gap is to be provided between the layers (eg of 1 - 2 mm only) to reduce the overall thickness of the insulating unit, inserts of tape impregnated with desiccant may be sufficient to space them apart instead of spacer material.

A preferred range of thickness of such a triple glazed unit, that is to say from the inner surface of the inner layer to the outer surface of the outer layer is between 24 mm and 32 mm.

Such a window unit is preferably constructed by what is known as a dual seal process. The first seal, known as the primary seal, is provided by the bonding agent on the spacer material and initially seals the spacer material to the respective layers of glazing during assembly. The second seal is made using the same process as for a standard insulating glass unit outer seal, using an appropriate material, for example polysulphide or polyurethane cold mix process or a butyl based hot melt process.

Such a window unit and the layers within it, are of course, cut to size, prior to assembly so that the unit is compatible for installation into a pre-existing frame or window opening as required.

In other embodiments in accordance with the invention, there may be no gaps between the inner and central layers and the central and outer layers, respectively. In other words, the central layer may simply be sandwiched between the inner and outer layers so as to occupy the space between those layers which has been provided by the disposition of spacer material between those layers. In fact the central layer of plastics material may occupy the original cavity between glass layers in a standard double glazed unit to provide a unit of enhanced resistance to breakage or attack, notwithstanding some loss of the original insulating properties afforded by the original air gap.

The present invention will now be more particularly described with reference to the accompanying drawings in which: Figure 1 is a partial section through a first embodiment of a window unit according to the present invention;

Figure 2 is a partial section through a second embodiment of a window unit according to the present invention; and

Figure 3 is a partial section through a third embodiment of a window unit according to the invention.

Referring to figure l there is shown a triple glazed security and insulating window unit 10. The unit comprises inner and outer layers 12 and 14 of laminated glass and a central layer 16 of indestructible translucent plastics material available under the registered trade mark LEXAN.

The layers 12, 14 and 16 are assembled together with the provision of spacer bars 18 and 20 between the layers 12 and 16 and 16 and 14 respectively. A primary seal 22 is provided between the spacer bars 18 and 20 and the central layer 16 and each of the outer layers 12 and 14 respectively.

A secondary seal 24 provides the outer seal for the window unit to provide a barrier to the ingress of moisture.

In a further arrangement (not shown) the spacer bars 18 and 20 can be replaced by a length or lengths of spacing material, such as that available under the trade mark EDGETECH. This latter material is impregnated with a desiccant substance at the time of manufacture. The purpose of the desiccant is to absorb any moisture from the cavities (gaps) after the unit is closed and sealed.

It will be appreciated that the window unit illustrated in figure 1 acts both as a security barrier, because of the unbreakable central layer, and also as an insulating unit because of the spaces between the central layer 16 and the inner and outer layers 12 and 14.

Such units have been found to be particularly effective in resisting any form of physical attack or breakage as well as having excellent sound and thermal insulating properties.

Referring to figure 2, there is shown a window unit 26 which is arranged to allow for expansion of the central layer 16 in environments where relatively high ambient temperatures may be experienced.

Around its edges the central layer 16 is fitted into channel section members 28, preferably of aluminium, and it is these members 28 which are bonded to the spacer bars 18, 20 by the primary seal 22 and the inner and outer layers 12, 14 by the secondary seal 24. The central layer 16 itself is sized to provide a small gap 30 around at least three of its edges so that it is free to move laterally within the space defined by the channel section members 28.

Because of the provision of a peripheral gap 30 around at least three sides of the central layer 16 the layer 16 can expand and contract without affecting either the primary or secondary seals 22, 24.

However, the window unit 26, whilst remaining effective as a security window unit, may not have the full insulating properties of the window unit 10 illustrated in figure 1, the reason being that air in the exterior cavity, ie the gap between layers 14 and 16, is in communication with air in the inner cavity, ie the gap between layers 12 and 16.

Referring to figure 3, there is shown a window unit 32 where there are no gaps or only negligible gaps between the central layer 16 of indestructible plastics laminate and the inner and outer layers 12, 14 of laminated glass. The same reference numerals have been used in respect of this embodiment as in the previous two for parts which are directly compatible.

Spacer bars 20 are provided in this case between the inner and outer layers 12, 14, a primary seal 22 being formed between the bars 20 and the respective inner and outer layers. The central layer 16 is cut to size to fit between the spacer bars 20, in the central cavity they have defined between the said inner and outer layers. Thus, the central layer 16 is of substantially the same thickness as the spacer bars 20 and the overall thickness of the glazed unit is reduced by this arrangement if the layers 12, 14, 16 are kept of the same thickness as in the earlier embodiments.

The central layer 16 is, in this embodiment, so dimensioned as to leave a gap 30 around the edges between said layer 16 and the surrounding spacer bars 20 so that the central 16 is free to expand laterally, without pressure on the spacer bars 20 and a risk of impairing the bonding between these bars 20 and the inner and outer layers 12, 14. The avoidance of direct bonding between the contacting faces of the central layer 16 and the inner and outer layers 12, 14 avoids other problems associated with differing thermal expansion of the materials of the layers 12, 14 and 16.

This last embodiment represents a way of providing a means of security, ie resistance to shattering, of a standard double glazed unit, by fitting the additional central layer into the central cavity before the sealing of the unit is completed. Such a unit would be used in locations where security is more important than insulation or minor defects in light transmission. It is recommended that the installation of window units is carried out in accordance with a non-removable procedure. For example, the window unit should be bedded and internally sealed with a non-hardening compound, such as a silicone sealant, appropriate for glass and plastic combined, ensuring that there is a strong adhesion between an interior uPVC rebate and the surface of the inner leaf of glass of the window unit.

Claims

1. A glazed window unit consisting of three layers, namely a central layer comprising a sheet of shatterproof translucent plastics material, and an outer layer and inner layer, both of glass, the central layer being mounted between the inner and outer layers but not being directly bonded to either of them..

2. A unit as claimed in claim 1 wherein the central layer consists of a single sheet of a polycarbonate resin.

3. A unit a claimed in claim 1 or 2 wherein the central layer is in the range 2mm to 10mm in thickness.

4. A unit as claimed in claim 1, 2 or 3 wherein one or both of the inner and outer layers consists of laminated glass.

5. A unit as claimed in any preceding claim wherein the inner and outer layers are each in the range of 2 to 12mm in thickness.

6. A unit as claimed in claim 4 wherein the inner and outer layers are each in the range 6.4 to 11.5mm in thickness.

7. A unit as claimed in any preceding claim wherein the outer layer and the inner layer are each spaced from the central layer.

8. A unit as claimed in claim 7 wherein the outer layer and the inner layer are each spaced from the central layer by a respective gap in the range 3 to 24mm in thickness.

9. A unit as claimed in any preceding claim wherein the central layer has edges which are fitted into channel section members and is sized to provide a small gap around at least three of its edges so that it is free to expand laterally within the space defined by the channel section members.

10. A unit as claimed in any of claims 1 to 6 wherein the central layer is sandwiched between the inner and outer layers and surrounded by spacer means which are connected to the inner and outer layers.

11. A unit as claimed in claim 10 wherein the central layer is sized to provide a small gap between at least three of its edges and the spacer means so that it is free to expand laterally within the space defined by the spacer means.

12. A glazed window unit substantially as hereinbefore described with reference to and as illustrated in figure 1, or figure 2, or figure 3 of the accompanying drawing.