GB2349397A

GB2349397A - Metal cassette type cladding panel

Info

Publication number: GB2349397A
Application number: GB0004619A
Authority: GB
Inventors: Stuart Campbell
Original assignee: CGL COMETEC Ltd
Current assignee: CGL COMETEC Ltd
Priority date: 1999-03-02
Filing date: 2000-02-29
Publication date: 2000-11-01
Also published as: IE20000161A1; GB0004619D0

Abstract

A panel has front and rear faces (1, 2), first and second side return portions each comprising first and second elements (5, 6) and top and bottom return portions (4, 12), where the first elements are folded such that they are at right angles to the rear face of the panel and the second elements, located adjacent the first elements, are folded such that they are at right angles to the first elements and parallel with the rear face of the panel and the second elements are attached to corner portions (8) located at each end of the top and bottom return portions. The corner portions may be fixed to the second elements of the side portions by a fixing plate which is not visible from the exterior of the panel and the second return elements may include apertures (7) to allow attachment to a building. The panel may be stiffened vertically or horizontally or in both directions (Figures 4a and 5a). The internal folding radius of the panel is intended to be one times the thickness of the panel material rather than more typically two to threes times the thickness of the panel.

Description

METAL CLADDING PANELS The present invention relates to the field of metal cladding products for the cladding of building facades.

More particularly, the present invention relates to a method of producing panels for use in such cladding of buildings.

In the early 1980s, new heat loss regulations were introduced for buildings. In response to these regulations, cladding systems were introduced not only to keep heat in, but also in order to protect the building from the environment. A standard rainscreen cladding system uses rails which are attached via brackets to the structural walls of a building. The cladding panels are then secured to the rails by panel holders. The panels are most commonly produced from aluminium, stainless steel, zinc, or a variety of composite materials.

In recent years, the use of pre-finished panels has become increasing popular, as architects and builders look for ways to reduce both costs and the time taken to clad a building. With aluminium in particular, the pre-finishing of the panels has produced a new series of problems for the producers of the cladding panels.

In the production of the panels, the aluminium sheet must be punched and folded to produce panels of the required size. With pre-finished panels, the folding and punching methods currently in use can damage the finish of the sheets.

This damage is particularly true of aluminium sheets.

For example, in the punching process drilling should not be used, as swarf and drill filings from the drilling can scratch the finish. Also, in the folding of the panels to produce corners, the finish can also be damaged. At present, to avoid such damage sheet manufacturers typically recommend that the internal folding radius used on a punched aluminium sheet is 2.5 times the thickness of the sheet. However, this radius makes it difficult for panel manufacturers to produce neat corners on their panels. We have discovered that it is possible to use internal folding radii of only 1 times the thickness of the aluminium sheet so as to produce a neat corner for the panel. It has been found with the present invention that this smaller folding radius produces this neater corner, but still does not damage the finish of the sheet.

A mitred corner arrangement similar to that used in the method of the present invention has been known for some time for use with aluminium composite sheeting, that is sheeting which comprises a synthetic resin core with the main faces covered with very thin aluminium sheet, with the back of the sheet being prescored before bending. However, when attempting to create such an arrangement using a 2mm or 3mm thick metal sheet utilising the large folding radii currently recommended, a"beaking"appearance remains which disfigures the corner. By using a small fold radius, the"beaking"does not appear and the neat corner arrangement is achieved. In addition, to fix the mitred corner to the side of the panel, the present invention uses a hidden fixing which is not visible on the exterior of the panel. In this way, the neatness of the corner arrangement is not disrupted by an external fixing or weld.

Therefore, it is the aim of the present invention to provide a method of producing cladding panels from prefinished metal sheets where the corner arrangements of the panels are fixed to the panel by concealed fixing means, so that the neatness of the corner arrangement is not disrupted by visible fixing means.

According to a first embodiment of the present invention, there is provided a metal cassette panel comprising: a planar panel portion having front and rear faces and first and second pairs of generally parallel opposite edges; top and bottom return portions provided on said panel adjacent said second pair of edges; and first and second side return portions, each provided on said panel adjacent to one of said first pair of edges ; wherein said first and second side return portions each comprise first and second return elements, said first elements being adjacent each of said first pair of edges and generally at right angles thereto, and said second elements each having an inner face and being adjacent said first elements and being generally at right angles thereto, said second elements being generally parallel to said rear face and spaced therefrom, said inner face facing said rear face of said panel ; and wherein each of said top and bottom return portions has a pair of corner portions at opposite ends thereof, said corner portions being fixedly attached to said second elements.

Preferably, each of said corner portions is fixedly attached to said second elements by a plate member, said plate members being fixed to said corner portions and said inner faces of said second elements by fixing means. Preferably, said fixing means is a plurality of spot clinches.

Preferably, said second return elements each contain at least one aperture. Preferably, said apertures are adapted to receive attachment members of a building cladding system.

Preferably, said panel further comprises stiffening means, said stiffening means comprising at least one vertical support member fixedly attached to said top and bottom return portions. Alternatively, said stiffening means comprises at least one horizontal support member fixedly attached to said first and second side return portions. Alternatively, said stiffening means comprises at least one vertical support member fixedly attached to said top and bottom return portions, and at least one horizontal support member fixedly attached to said first and second side return portions.

Preferably, said stiffening means are fixedly attached by self-piercing rivets. Alternatively, said stiffening means are fixedly attached by self-piercing rivets and an adhesive.

According to a second aspect of the present invention, there is provided a method of producing metal cassette panels comprising the steps of: cutting a sheet of metal so as to provide a substantially planar cruciform sheet comprising a generally rectangular body portion defined by first and second pairs of generally parallel opposite crease lines, elongate top and bottom flaps adjacent said second pair of crease lines and a pair of elongate side flaps adjacent said first pair of crease lines, said top and bottom flaps each having a tab portion located at opposite ends thereof, said side flaps each having a cavity at opposing ends thereof, and each of said side flaps having a third crease line which generally bisects said side flaps such that said side flaps each comprises a first element adjacent said body and a second element adjacent said first element and separated therefrom by said third crease line; folding said side flaps and said top and bottom flaps along said first and second pairs of crease lines respectively, such that each of said flaps lies generally at right angles to said body portion; folding said side flaps along said third crease lines such that each of said first elements generally lies at right angles to said rectangular sheet, and each of said second elements generally lies at right angles to each of said first elements such that said second element is generally parallel to said rectangular sheet; folding said tab portions such that they occupy the respective cavities of said side flaps; and fixedly attaching said folded tab portions to said second elements of said side flaps.

Preferably, each of said tab portions is fixedly attached to said second elements by a plate member, said plate members being fixed to said tab portions and said inner faces of said second elements by fixing means. Preferably, said fixing means is a plurality of spot clinches.

Preferably, said method further comprises the step of cutting at least one aperture in each of said second elements. Preferably, said apertures are adapted to receive attachment members of a building cladding system.

Preferably, said method further comprises the step of fixedly attaching stiffening means to said panel.

Preferably, said stiffening means comprises at least one vertical support member fixedly attached to said top and bottom flaps. Alternatively, said stiffening means comprises at least one horizontal support member fixedly attached to said side flaps. Alternatively, said stiffening means comprises at least one vertical support member fixedly attached to said top and bottom flaps, and at least one horizontal support member fixedly attached to said side flaps.

Preferred embodiments of the present invention will now be described with reference to the accompanying drawings, wherein: Figures 1 (a) and l (b) show projected rear and front views, respectively, of an aluminium panel in accordance with the present invention; Figure 2 (a) shows an isometric view of the top corner of the panel of Fig. l (a); Figure 2 (b) shows a section view through section A-A of Fig. 2 (a); Figure 2 (c) shows a view on arrow B of Fig. 2 ; Figure 2 (d) shows a view of the top corner of the punched aluminium sheet prior to folding; Figure 3 (a) shows an isometric view of the bottom corner of the panel of Fig. l (a); Figure 3 (b) shows a section view through section A-A of Fig. 3 (a); Figure 3 (c) shows a view on arrow B of Fig. 3 ; Figure 3 (d) shows a view of the bottom corner of the punched aluminium sheet prior to folding; Figures 4 (a) and 4 (b) show the views of the panel of Figs. leva) and l (b) with a vertical railholder attached; Figures 5 (a) and 5 (b) show the views of the panel of Figs. 1 (a) and l (b) with a horizontal stiffener attached; Figures 6 (a) and 6 (b) show the views of the panel of Figs. 1 (a) and l (b) with the vertical railholder and horizontal stiffener attached; Figure 7 (a) shows an isometric view of the top of the vertical railholder of Fig. 6 (a); Figure 7 (b) shows an exploded isometric view of the top of the vertical railholder of Fig. 6 (a); Figure 7 (c) shows a section view through section A-A of Fig. 7 (a); Figure 7 (d) shows a section view through section B-B of Fig. 7 (b); Figure 8 (a) shows an isometric view of the bottom of the vertical railholder of Fig. 6 (a); Figure 8 (b) shows an exploded isometric view of the bottom of the vertical railholder of Fig. 6 (a); Figure 8 (c) shows a section view through section A-A of Fig. 8 (a); Figure 8 (d) shows a section view through section B-B of Fig. 8 (b); Figure 9 (a) shows an isometric view of the horizontal stiffener as shown in Fig. 6 (a); Figure 9 (b) shows an isometric view of the intersection between the horizontal stiffener and vertical railholder as shown in Fig. 6 (a); Figure 9 (c) shows a section view through section A-A of Fig. 9 (a); and Figure 9 (d) shows a section view through section B-B of Fig. 9 (b).

Figures l (a) and l (b) show the standard configuration of a panel according to the present invention for attaching to the rail of a building cladding system via panel holders. The panel has a front face 1 and a rear face 2, with the height and width of the faces 1,2 being variable depending on the requirements of the cladding job.

The panels are formed from sheets of metal, the most common metals used for the sheets being aluminium, zinc, copper, stainless steel and aluminium composites.

The favoured material for this preferred embodiment is prepainted aluminium sheet by Reynolds Aluminium, most suitably REYNOCLAD prepainted sheet of 5754 series aluminium of 2.00 mm thickness. A number of paint finishes are available, but the preferred finish is polyvinylidenefluoride. We have established that this material can be bent to a 2.00 mm radius without affecting the adhesion and integrity of the paint film.

The sheets are punched using a Computer Numerically Controlled (CNC) punch. The punched sheets can be seen in Figures 2 (d) and 3 (d). The panel return sizes of the panel are standardised and do not vary no matter the height and width of the faces 1,2. At present, the sheet manufacturers recommend using an internal folding radius for the folding of the punched sheets of 2.5 times the thickness of the sheet. However, this creates difficulty in producing a neat corner on the panel. Therefore, the present embodiment uses internal folding radii of only 1 times the thickness of the sheet to achieve a neat corner, and suffers no noticeable damage to the components as a result. The folding is carried out by a combination of CNCcontrolled brake presses and manual folding.

Figure 2 (d) shows one of the pre-folded top corners of the panel. Side portions 5,6 are folded in towards rear face 2 of the sheet along fold line 30, so that the side portions 5,6 are at 90 to the rear face 2.

Side portion 6 is then folded in by a further 90 along fold line 31 towards rear face 2, so that side portion 6 is then substantially parallel to rear face 2, the two separated by the width of side portion 5.

At the top of the sheet, top portion 3, lip portion 4, and corner portion 8 are folded in towards the rear face 2 by 90 along fold line 32. However, lip portion 4 is then folded back out by 90 relative to the rear face 2 along fold line 33, so that the rear face 2 and lip portion 4 are substantially parallel to each other.

Corner portion 8 is then folded in by 90 along fold line 34, so that it meets with side portion 5. The corner portion 8 is then further folded along fold line 35 by 90 so as to meet with side portion 6. A fixing plate 10 is then placed over the join of side portion 6 and corner portion 8 and fixed in place using a pair of spot clinches 9, thus securing the corner. However, as the fixing plate 10 is fixed to the inner face of the side portion 6, the fixing is not visible on the exterior of the panel. Thus, the fixing of the corner portion 8 to the side portion 6 does not affect the clean lines of the mitred corner. The resultant positions of the portions can be seen in Figures 2 (a) (c). The process is repeated for the other top corner.

Figure 3 (d) shows one of the bottom corners of the sheet. As mentioned above, the side portions 5,6 are folded in towards the rear face 2 along fold lines 30 and 31, leaving side portion 6 substantially parallel to the rear face 2. Bottom portion 11, lip portion 12, and corner portion 13 are folded towards the rear face 2 by 90 along fold line 36. Lip portion 12 is then folded by a further 90 towards the rear face 2 so that the lip portion 12 and rear face 2 are substantially parallel, the two separated by the width of the bottom portion 11.

Once the bottom and lip portions 11,12 are folded into position, corner portion 13 is folded in 90 along fold line 38 so that the corner portion 13 meets the side portion 5. The final folding is to fold the corner portion 13 towards the rear face 2 by 90 , so that the corner portion 13 also meets side portion 6. Once the corner portion 13 meets side portion 6, a fixing plate 10 is placed over the join and secured using a pair of spot clinches 9, thus securing the bottom corner.

Again, the fixing plate 10 is on the inner face of the side portion 6 so as not to disrupt the clean corner arrangement. The resultant positioning of the portions can be seen in Figures 3 (a)- (c). The above process is then repeated for the other bottom corner.

In this way, the fixing of the corners is hidden from view, and so are the panel holders which secure the panel to the cladding system of the building.

The finished panel returns on the panel have panel holder apertures 7 situated at the rear of the panel to attach the panel to the cladding system via panel holders (not shown). In addition, bottom portion 11 has a number of drainage holes 14 to prevent water gathering in the bottom lip of the panel.

For larger panel sizes, a support may be secured to the rear face 2 of the panel to provide more attachment points and thus a more secure panel against windloading. Such a support 15 can be seen in Figure 4. The means by which the support 15 is secured to the top and bottom lips of the panel can be seen in Figures 7 (a)- (d) and Figures 8 (a)-(d). The support 15 is secured to the top and bottom lips of the panel by a top connector 17 and a bottom connector 21, respectively. The top connector 17 fits flush against lip portion 4 and top portion 3 with the lower portion 17a of the top connector 17 fitting into slots 18 provided in the top of the support 15. The top connector 17 is then secured to the lip portion 4 by a pair of self-piercing rivets 16 which are fed through a pair of flange portions 20 of the top connector 17 into the lip portion 4.

A similar securing technique is used at the bottom lip of the panel, where a pair of slots 22 in the support 15 receive the bottom connector 21. The bottom connector 21 is then secured to the bottom lip of the panel by way of a pair of self-piercing rivets 16. In addition to the attachment by rivets 16, the support 15 is further secured to the rear face 2 of the panel by adhesive-tape 19 which is bonded to the rear face 2.

To provide more structural rigidity to the larger panels, a horizontal stiffener can also be utilised, and such a horizontal stiffener 25 can be seen in use in Figure 5. The attachment method for the stiffener 25 can be seen in detail in Figures 9 (a) and 9 (c), wherein the stiffener 25 has a pair of slots 27 at either end which receive a horizontal connector 24. A flange portion of the horizontal connector 24 is then fitted flush to the side portion 6 of the panel and secured by way of a pair of spot clinches 23. As with the vertical support 15 described above, the stiffener 25 is additionally secured to the rear face 2 of the panel by adhesive tape 28 bonded to the rear face 2, the adhesive tape 28 being attached to lip portions 26 of the stiffener 25.

Figure 6 shows the arrangement of a pair of stiffeners 25 and a support 15 when both are required to be fitted to the rear face 2 of a panel. The detail of the attachment between the stiffeners 25 and support 15 can be seen in Figure 9 (b), although the components are the same as those described above in Figure 9 (a), with the exception that the horizontal connector 23 is attached to the support 15 as opposed to the side portion 6 of the panel.

The horizontal stiffener 25 and vertical support 15 are attached to the rear face 2 of the panel by bonded adhesive tape 19,28 due to the fact that the use of pre-finished aluminium sheet precludes the use of any welding. In attaching the stiffener 25 and/or support 15 to the rear face 2 the adhesives 19,28 are essential, but they are very difficult to reposition after the component is attached to the rear face 2.

Therefore the sliding connectors 17,21,24 are used to attach the stiffener 25 or support 15 to the panel lip portions so that the connector 17,21,24 can be moved after the adhesive 19, 28"grabs"and the connector can then be spot clinched to the panel lip portions and/or support 15.

One purpose of the present invention is to ensure that the finish of the metal sheet is not damaged during production of the panel. Therefore, with the care taken during production, care must also be taken during packaging and delivery of the finished panels. Thus, when the panels are packed, they are packed vertically, back-to-back and face-to-face, and are linked together by fabricated hooks which engage in panel slots 50.

The outside panels on a pallet are secured to the pallet via screws in the drainage holes 14 of the bottom lip of the panels. In this way, a secure pallet of panels is able to be transported without damage due to movement or scraping. To aid this, all the panel returns, railholders, and stiffeners are in the same plane.

Modifications and improvements may be incorporated without departing from the scope of the invention.

Claims

CLAIMS: 1. A metal cassette panel comprising: a planar panel portion having front and rear faces and first and second pairs of generally parallel opposite edges; top and bottom return portions provided on said panel adjacent said second pair of edges; and first and second side return portions, each provided on said panel adjacent to one of said first pair of edges; wherein said first and second side return portions each comprise first and second return elements, said first elements being adjacent each of said first pair of edges and generally at right angles thereto, and said second elements each having an inner face and being adjacent said first elements and being generally at right angles thereto, said second elements being generally parallel to said rear face and spaced therefrom, said inner face facing said rear face of said panel; and wherein each of said top and bottom return portions has a pair of corner portions at opposite ends thereof, said corner portions being fixedly attached to said second elements.
2. The panel according to Claim 1, wherein each of said corner portions is fixedly attached to said second elements by a plate member, said plate members being fixed to said corner portions and said inner faces of said second elements by fixing means.
3. The panel according to Claim 2, wherein said fixing means is a plurality of spot clinches.
4. The panel according to any preceding claim, wherein said second return elements each contain at least one aperture.
5. The panel according to Claim 4, wherein said apertures are adapted to receive attachment members of a building cladding system.
6. The panel according to any preceding claim, wherein said panel further comprises stiffening means.
7. The panel according to Claim 6, wherein said stiffening means comprises at least one vertical support member fixedly attached to said top and bottom return portions.
8. The panel according to Claim 6, wherein said stiffening means comprises at least one horizontal support member fixedly attached to said first and second side return portions.
9. The panel according to Claim 6, wherein said stiffening means comprises at least one vertical support member fixedly attached to said top and bottom return portions, and at least one horizontal support member fixedly attached to said first and second side return portions.
10. The panel according to any of Claims 6 to 9, wherein said stiffening means are fixedly attached by self-piercing rivets.
11. The panel according to any of Claims 6 to 9, wherein said stiffening means are fixedly attached by self-piercing rivets and an adhesive.
12. A method of producing metal cassette panels comprising the steps of: cutting a sheet of metal so as to provide a substantially planar cruciform sheet comprising a generally rectangular body portion defined by first and second pairs of generally parallel opposite crease lines, elongate top and bottom flaps adjacent said second pair of crease lines and a pair of elongate side flaps adjacent said first pair of crease lines, said top and bottom flaps each having a tab portion located at opposite ends thereof, said side flaps each having a cavity at opposing ends thereof, and each of said side flaps having a third crease line which generally bisects said side flaps such that said side flaps each comprises a first element adjacent said body and a second element adjacent said first element and separated therefrom by said third crease line; folding said side flaps and said top and bottom flaps along said first and second pairs of crease lines respectively, such that each of said flaps lies generally at right angles to said body portion; folding said side flaps along said third crease lines such that each of said first elements generally lies at right angles to said rectangular sheet, and each of said second elements generally lies at right angles to each of said first elements such that said second element is generally parallel to said rectangular sheet; folding said tab portions such that they occupy the respective cavities of said side flaps; and fixedly attaching said folded tab portions to said second elements of said side flaps.
13. The method according to Claim 12, wherein each of said tab portions is fixedly attached to said second elements by a plate member, said plate members being fixed to said tab portions and said inner faces of said second elements by fixing means.
14. The method according to Claim 13, wherein said fixing means is a plurality of spot clinches.
15. The method according to any of Claims 12 to 14, further comprising the step of cutting at least one aperture in each of said second elements.
16. The method according to Claim 15, wherein said apertures are adapted to receive attachment members of a building cladding system.
17. The method according to any of Claims 12 to 16, further comprising the step of fixedly attaching stiffening means to said panel.
18. The method according to Claim 17, wherein said stiffening means comprises at least one vertical support member fixedly attached to said top and bottom flaps.
19. The method according to Claim 17, wherein said stiffening means comprises at least one horizontal support member fixedly attached to said side flaps.
20. The method according to Claim 17, wherein said stiffening means comprises at least one vertical support member fixedly attached to said top and bottom flaps, and at least one horizontal support member fixedly attached to said side flaps.
21. The method according to any of Claims 17 to 20, wherein said stiffening means are fixedly attached by self-piercing rivets.
22. The method according to any of Claims 17 to 20, wherein said stiffening means are fixedly attached by self-piercing rivets and an adhesive.