"A translucent panel"

Introduction

The invention relates to a translucent panel.

In general, translucent roof panels (also called rooflights) comprise an outer translucent weather sheet and an inner translucent liner sheet.

One of the problems with conventional rooflights is that they are not efficient insulators and the rate of heat loss through the rooflights is relatively high. Another problem is that conventional rooflights must be relatively thick to achieve desired insulation properties. Thus, the rooflights are expensive in material usage.

In our GB 2413808A we have described a translucent panel comprising a single body comprising an outer weather skin, an inner liner skin and a multiwall support between the skins. The panel has an integral overlap portion.

There is a need to provide an improved panel of this type.

Statements of Invention

According to the invention there is provided a translucent panel comprising a single body of translucent material, the single body comprising an outer weather skin, an inner liner skin and a multiwall support between the outer weather skin and the inner liner skin, the inner liner skin, outer weather skin and multiwall support all being of translucent material, the panel further comprising an integral overlap portion at at least one end and/or side thereof, the overlap portion being sealed.

In one embodiment the end edge of the overlap portion is sealed.

The end edge of the overlap portion may be heat sealed.

In one case a sealed part of the overlap portion has a thickness less than that of the outer weather skin.

The sealed part may be at or adjacent to the end edge of the overlap portion.

In one embodiment the multiwall support with or without the liner skin is collapsed against the inner surface of the outer weather skin at the overlap portion.

In another embodiment the multiwall support with or without the inner skin is forced against the inner surface of the outer weather skin at the overlap portion.

In a further embodiment the multiwall support with or without the liner skin is pressed against the inner surface of the outer weather skin at the overlap portion.

In one embodiment the multiwall support with or without the liner skin is heat pressed against the inner surface of the outer weather skin at the overlap portion.

In another embodiment the liner skin and the multiwall support are collapsed or forced against the inner surface of the outer weather skin at the overlap portion.

In a further embodiment the panel comprises a main panel portion, the overlap portion and a border between the overlap portion and the main panel portion.

In one embodiment the border extends between the outer weather skin of the overlap portion and the inner liner skin of the main body.

In another embodiment the border extends substantially at right angles to the outer weather skin and inner liner skin.

In a "further embodiment the border comprises a thickness substantially equal to the combined thickness of the multiwall support and inner liner skin.

In one embodiment the panel comprises a spacer for extending between the outer surface of the inner liner and a building frame element such as a purlin.

In another embodiment the spacer is attached to the panel.

In a further embodiment the spacer is bonded to the panel.

In one embodiment the spacer is attached to the panel adjacent to the overlap portion.

In another embodiment the translucent panel comprises a fixing for extending through the panel and the spacer to fix the panel to a building frame element such as a purlin.

In a further embodiment the fixing has a drill point for drilling through the panel, the spacer, and into a building frame element.

In one embodiment the fixing comprises reaming means for reaming a hole in the panel.

In another embodiment the hole in the panel is larger in diameter than the diameter of a main shaft of the fixing.

In a further embodiment the reaming means comprises sharpened flanges in the fixing shaft.

In one embodiment the outer weather skin comprises a profiled form.

In another embodiment the multiwall layer comprises a profiled form except at the overlap portion.

In a further embodiment the translucent material comprises a translucent thermosetting material.

In one embodiment the translucent material comprises a polycarbonate material.

The invention also provides a roof or wall structure incorporating a panel of the invention.

Brief Description of the Drawings

The invention will be more clearly understood from the following description thereof given by way of example only, with reference to the accompanying drawings, in which:-

Fig. 1 is a perspective view of a translucent panel according to the invention, in use;

Fig. 2 is a perspective view from the underside of the panel;

Fig. 3 is a side view of the panel;

Fig. 4 is an end view of the panel;

Figs. 5 (a) to 5(g) are side views illustrating the collapsing of inner liner skin and multiwall support at an overlap portion;

Fig. 6 is an enlarged end view of an overlap portion prior to collapsing of the inner liner skin and multiwall support;

Fig. 6(a) is an enlarged end view of the overlap portion after first stage collapsing of the inner liner skin and multiwall support;

Fig. 6(b) is an enlarged end view of the overlap portion prior to second stage collapsing of the inner liner skin and multiwall support;

Fig. 6(c) is an enlarged end view of the overlap portion after second stage collapsing of the inner liner skin and multiwall support;

Fig. 6(d) is an enlarged view of part of the overlap portion, after collapsing;

Fig. 6(e) is a cross-sectional view of the overlap portion showing the end collapse/sealing;

Fig. 7 is a perspective view of a fixing used with the panel; and

Fig.8 is an end view of the panel, and a spacer fixed to a purlin using the fixing of Fig. 7.

Detailed Description

Referring to the drawings there is illustrated a translucent panel or rooflight 1 comprising a single body of translucent polycarbonate material, the single body comprising a profiled outer weather skin 2, an inner liner skin 3 and, a multiwall support 4 between the inner liner 3 and the weather skin 2. The inner liner skin 3, outer weather skin 2, and the multiwall support are all of translucent polycarbonate material. The rooflight 1 may be of Lexan Thermoclear multiwall polycarbonate sheet from GE Structural Products. This material is highly resistant to sheet covering discoloration, loss of light and loss of strength due to weathering.

The panel 1 has an integral overlap portion 10 which is illustrated in this case at one end of the panel. This is used for overlapping with other panels such as composite insulating roof or wall panels of similar profile. The overlap portion 10 has a substantially reduced thickness with respect to the overall thickness of the panel and in this case the thickness is reduced to close to thickness of the outer weather skin 2.

Referring in particular to Figs. 5 and 6 this is achieved by collapsing and/or forcing the inner liner skin 3 and the multiwall support 4 in the region of the overlap towards the outer weather skin 2. In a first step (Fig. 5(a)) the inner liner skin 3 is notched at 11 with a cutting tool 12. A first heated pressing tool 15 of complementary profile to that of the outer skin is then pressed against the inner liner skin 3 and multiwall support 4 (Figs. 5(b), 5(c)) which are melded to the inner surface of the outer skin 2 (Figs. 5(d), 6(a)). The melded material 19 is shown in exaggerated form and thickness in Fig. 6(a). In the invention, part of the overlap portion, in this case the end edge 60 is sealed to ensure that there is no possibility of water ingress at the end edge. The melded end edge 60 is particularly shown in Fig. 6(e). This is achieved in this case by a second stage pressing/heat sealing using a second pressing tool 21 which is pressed against the collapsed end edge 60 to further meld/seal the polycarbonate material. The melded/sealed end edge 60 ensures that there is no possibility of moisture, dirt or other ingress at this edge. Using a pressing tool is a very efficient method for manufacture on a large factory scale.

The panel 1 further comprises a border 25 extending between the main panel portion and the overlap 10. The border 25 has a depth comprising the overall depth of the multiwall support 4 and the inner liner skin 3 and extends substantially at right angles to the outer weather skin 2 and inner liner skin 3.

Formation of the notch 11 prior to pressing provides for the border 25 on pressing. In the preferred embodiment shown the notch 11 extends across the width of the panel, however, it will be appreciated that the depth and/or extent of the notch 11 may be varied as required.

In use, the border 25 and overlap portion 10 together define a connection means for connection of the panel 1 with adjacent panels having a similar profile. The adjacent panels may be rooflight panels or insulated building panels having the same profile as the outer weather skin. The adjacent panels may be of a similar or greater thickness than the panel 1. The panel 1 is configured so that in use the overlap 10 overlaps an adjacent panel of a similar profile and the border 25 lies side by side in close abutment with the side edge of the adjacent panel. A sealing member for example, a tape covering may be applied to the border 25. The overlap 10 and border 25 provide for an improved connection between the panels 1 and adjacent roof panels and also for improved seal and insulation of the roofing system.

As noted above, the pressing tool has the profile of the outer skin 2 so that the inner liner skin 3 and multiwall support 4 are compressed against the outer skin, but the overall profile of the outer skin is maintained. The overlap 10 extends laterally across the width of the panel 1. In the embodiment shown the outer skin 2 is profiled and the overlap is formed in such a way as to maintain the profile of the outer weather skin at the overlap 10. This provides a good aesthetic finish to the roof and ensures that an improved seal and connection is achieved between the panel 1 and adjacent panels.

In addition to the overlap portion 10 which in the embodiment shown extends laterally, the panel 1 further comprises a side lap 26 (Figs. 1 and 2) which extends longitudinally along one side of the panel 1. The side lap 26 in this case comprises only the outer skin 2 and provides means for connection with adjacent profiled building panels or adjacent like panels 1. If necessary the side lap 26 may be formed in process similar to that for forming the overlap 10.

The panel 1 also comprises at least one and in this case a number of spacers 20 for extending between the outer surface of the inner liner 3 and a building frame element such as a roof purlin 40. The spacer 20 may for example be of hollow PVC section.

For ease of use on-site, preferably the spacer 20 is attached, for example by bonding

such as adhesive bonding, to the panel 1 at the production stage. The spacers 20 are used to bridge the gap in thickness between the shallow rooflight 1 and an adjacent thicker composite insulated panel. The rooflight is shallow because of the high thermal insulation efficiency of the translucent panel.

It is noted that the border 25 provides a clearly defined attachment region to enable attachment of spacers directly adjacent to the overlap portion 10 of the panel 1. In this way a spacer 20 can be located side by side with the side edge of an adjacent panel so that the border 25 and the spacer 20 together overlap portions of the side edge of an adjacent insulated panel. The insulated panel may have a thickness greater than the thickness of the panel 1 at the border. This provides for a good seal and good insulation at the connection.

Referring in particular to Figs. 7 and 8 there is illustrated a fixing 30 which is used for fixing the panel 1 to a building frame element such as the roof purlin 40. The fixing has a shaft 31 with a drill point 32 for drilling through the panel, the spacer 20, and into the purlin 40. The fixing also has sharpened side flanges 33 which provide reaming elements for reaming a hole 35 in the panel 1 that is larger in diameter than the diameter of the shaft 31 of the fixing. Such large holes 35 in the panel facilitate any thermal expansion that may occur in the panel without adversely affecting the integrity of the panel at the fixings.

The rooflights of the invention have excellent U- value ratings, do not suffer from the effects of thermal expansion and provide excellent light transmission properties.

In the embodiment described the panel is comprised of a translucent polycarbonate material. It will however, be appreciated that the panel may be comprised of any suitable thermosetting material.

The process of forming the rooflights 1 of the invention as described has advantages including being efficiency and cost effectiveness. It will however be appreciated that the rooflights of the invention may be formed by other suitable means.

The rooflights of the invention have advantages over prior art rooflights including the following. The provision of an overlap portion enables the rooflight panel to be securely connected to adjacent profiled structural roof panels. The profiled form of the rooflight overlap provides a good aesthetic finish and a positive connection between the panels and for an improved weatherproof sealed finish.

The rooflight of the invention comprises connection means to enable secure connection with adjacent similar rooflight panels and/or insulated building panels which may have a thickness greater than the thickness of the rooflight. The rooflight is configured to provide for a side by side connection of the rooflight with the adjacent panel by virtue of the overlap and border features. This arrangement provides improved sealing and insulation between the rooflights and adjacent roof panels.

The spacer and fixing features of the rooflights of the invention provide further advantages. The spacer provides for an improved structural connection between the panels and the roof system which provides a roof having improved insulation properties. The panel of the invention is formed to facilitate any thermal expansion that may occur in the panel.

The invention is not limited to the embodiments hereinbefore described which may be varied in detail.