Metal cladding systems

Abstract: The specification discloses a method of forming a self sustained cladding panel 10 for use in a cladding panel system for a building using a resilient metal or metal alloy sheet material. The panels have a central visible portion 12 and longitudinally extending side edges 14, 16. The central visible portion is formed into a plurality of longitudinally spaced facets, said central visible portion having, in its relaxed state, a shape which is significantly different from the intended final shape.

Description: The present invention relates to a metal cladding system for a building and to methods of its manufacture. The cladding systems may be used for example for covering the walls or ceilings of a building. Ceilings using elongate panels are usually formed from 0.5 mm thick aluminium strip, for example from an aluminium AL-Mg alloy such as AA 5050 having good formability by roll forming. Such a structure is shown, for example, in GB-A-2 164 972. The aluminium alloy AL-Mg/Si, such as AA 6011, used for venetian blind slats or other high manganese aluminium alloys such as AA 5182 used in the production of can bodies are of a stiffer grade and are much more resilient. Such hard alloy material is readily available in thicknesses of about 0.2 mm for use in the manufacture of venetian blind slats or can bodies. During the act of its forming, the characteristics and behaviour of these or other hard alloys can be somewhat compared to those of cardboard. If such materials were to be used for ceiling panels, then material costs would be drastically lowered, but the usual form of equipment and techniques involved cannot be used. The invention provides a method of providing a cladding panel for use in a cladding panel system for a building from a resilient metal or metal alloy sheet material, said panels having a central visible portion and longitudinally extending side edges, said method comprising the steps of initially forming said central visible portion into a plurality of laterally adjacent facets and providing the thus formed central visible portion so that it has, in its relaxed state, a shape which is significantly different from the intended final shape. One form of apparatus which may be utilized for roll forming a plurality of spaced or slightly concaved facets in sheet material comprises two oppositely disposed forming rolls, at least one of said rolls comprising axially spaced concave and convex portions, concave portions having a radius of curvature in excess of the radius producing permanent deformation of the sheet material to be formed and the convex portion having a radius of curvature sufficiently small to produce permanent deformation of the sheet material to be formed. According to another aspect of the invention there is provided a cladding panel for use in a cladding system for a building, said cladding panel comprises a stiff grade, high yield strength, resilient, aluminium alloy sheet, said panel having a generally central visible portion which is formed of a plurality of laterally adjacent facets, and which, in use, is bowed so that the junctions of the facets lie along a locus which has a radius of curvature which significantly exceeds the bend radius of the sheet material which would produce permanent deformation of the sheet material and longitudinally extending side edges each formed with a bead having a radius of curvature sufficiently small to produce a permanent deformation of the sheet material. Intermediate portions, for example substantially flat intermediate portions, may be provided, one on each side of the bowed central visible portion and extending therefrom to the beads on the longitudinal side edges. The beads may be connected to the intermediate portion by further portions angled with respect to the intermediate portions and extending, in use, substantially parallel to one another. The invention also contemplates the possibility of providing a cladding system comprising a plurality of panels, according to the invention, wherein additional short lengths of panel material are engaged over the panels at longitudinally spaced locations to give a patterned visual effect. These additional short lengths of panel material may be formed of a different colour from the remaining panel material to give a special decorative effect. In order that the present invention may more readily be understood, the following description is given, merely by way of example, reference being made to the accompanying drawings, in which:- Figure 1 is a schematic view of one embodiment of a ceiling panel according to the invention in its installed position; Figure 2 schematically illustrates forming rolls for forming the facets of the panel embodiment of Figure 1 as well as illustrating the sheet material before and after formation; Figure 3 shows a modification of assembling two panel portions end to end; Figure 4 shows an underneath plan of a patterned effect which can be achieved using the structure of Figure 3. Figures 5a-9a show structures of forming roll which are modifications of those shown in the centre of Figure 2; and Figure 5b-9b show the resulting cross-section of the sheet material after formation with the forming rolls of Figures 5a-9a, respectively. Referring first to Figure 1, there is illustrated a panel indicated by the general reference numeral 10 this having a generally central visible portion 12. Figure 1 illustrates how the central visible portion 12 is formed from a plurality of spaced flat or slightly concave facets 50 to produce a generally downwardly bowed configuration for the visible portion 12. Each facet 50 is connected to its neighbour by a curved connection portion 51 permanently formed in the slat material and having a radius of curvature preferably less than 2 mm. Figure 2 schematically illustrates two rolls 52 and 54 as having concave and convex axially spaced portions 56,58 respectively. The radius of curvature R of these portions is greater than the radius by which 0.2% yield of the material is produced and a radius of curvature r of the peaks 60 between the portions 56 of roll 52 is less than this 0.2% yield radius thereby providing the necessary permanent deformation. The flat sheet 64 is shown above the roll 52, 54 in Figure 2, that is the sheet before it is fed between the rolls. The resulting product, after being fed between the rolls 52,54 automatically adopts the bowed shape which is illustrated as 66 at the bottom of Figure 2. The panel obtained in this manner can be installed in a ceiling as shown in Figure 1 by significant further curvature of the visible portion from its already slightly curved relaxed shape by mounting the inwardly flexed longitudinal side edges 14,16 resiliently between spaced adjacent ceiling panels. By carrying out the deformation of the panels to the final shape so that the central visible portion has a shape which is significantly different from the relaxed original shape, adequate rigidity can be provided to the panels even if the material is relatively thin, for example if the sheet material has a thickness of less than 0.3 mm and even as little as 0.2 mm, that is to say material such as used in the manufacture of venetian blind slats. Thus, one can achieve very satisfactory results with much less expenditure on the materials than has hitherto been possible. A modified structure is illustrated in Figure 3. Here the edge parts 314a,316a and 314b,316b are flat and can overlie one another. The central portions, that is to say the visible portions 312a,312b are sufficiently resilient and flexible to enable them readily to be flexed and telescoped so that the two panel parts inter-engage and overlap. Use of such a structure may be made, by way of example, in a manner illustrated in Figure 4. Here the panels, which may be panels similar to those of the invention, or conventional panels of a rather thicker material, are indicated by the reference numerals 410. Decorative flexible portions, for example similar to those illustrated in Figure 3, which may, for example, be of a different colour, are flexed into place and are indicated by the general reference numeral 412. The actual configuration of these decorative portions 412 can be of any shape as desired to conform to the shape of the panels 410 which are being used. The length and the distributions and the shapes of the ends of the decorative portions 412 can be adapted in a number of different ways, some of which are illustrated in Figure 4, to give a particular visual effect. Figures 5a-9a show five further forms of roll which are shown as modifications of the forming rolls of Figure 2. In each instance the appropriate forming rolls have, on at least one forming roll, a portion for forming a transverse bend of a given radius of curvature R disposed between adjacent forming portions on the other forming roll for forming transverse bends of a smaller radius of curvature r. The magnitude of these radii of curvature is illustrated in terms of the thickness 't' of the sheet material. In Figure 5a the upper smaller radius of curvature r equals 3t while the lower smaller radius r' equals 1.5t. The resulting shape of the faceted panel is illustrated in Figure 5b. In Figure 6a the radii of curvature are the same as in Figure 5a but the extent of the radiused portion is different, thereby giving a rather flatter disposition of the undulations on the forming roll. Again the structure resulting in the faceted panel is illustrated in Figure 6b. In Figure 7a the radius of curvature R equals 50t and the radius r equals 2t. The format of the resulting product is illustrated in Figure 7b. Figure 8a has the same values for R and r', but the roll there illustrated is a barrel shaped roll, giving a slightly different resulting product shown in Figure 8b. The structure illustrated in Figure 9a has R equal to 100t and r equal to 2t, giving the product illustrated in Figure 9b. It is contemplated that these faceted structures may be used in arrangements other than in ceilings and could, for example, be used as slats of a vertical louvre blind.

Claims: A method of forming a profiled panel, said method comprising the steps of providing a pair of oppositely disposed forming rolls (52,54), one of said rolls (52) having axially spaced concave portions (56), each having a large radius (R), the portions (56) having therebetween peaks (60) having a small convex radius (r,r'), the other of said rolls (54) having complementary axially spaced convex portions (58) ; feeding hard, stiff grade, resilient metal or metal alloy sheet material between said rolls, the sheet material having a thickness (t), the radius of curvature (R) of the axially spaced complementary concave and convex portion (56,58) of the rolls being in excess of the radius producing permanent deformation of said sheet material and the peaks (60) having a radius of curvature sufficiently small to produce permanent deformation of said material. A method according to claim 1, wherein the radius of curvature (R) of the axially spaced complementary concave and convex portions (56,58) of the rolls is greater than 50 times the thickness (t) and the radius of curvature (r,r') of the convex peaks (6C) is less than 10 times the thickness (t), whereby permanent deformation of the sheet material is produced, to form junctions between facets in the finished panel. A method according to claim 1 or 2, wherein alternate peaks (60) of said one roll (52) have larger and smaller radii of curvature (r and r'). A method according to claim 1, 2 or 3, wherein said sheet material has a thickness of less than 0.3 mm. A method according to any preceding claims, wherein said peaks (60) of said one roll (52) have a radius of curvature of less than 2 mm. A method according to any preceding claim, wherein the radius of curvature (R) of the concave and convex portions (56,58) of the rolls (52,54) is greater than the radius by which 0.2% yield of the sheet material is produced. A panel produced by the method of any preceding claim, wherein, after forming of the sheet material, the panel has a central visible portion (12) which is formed of a plurality of uniform, laterally adjacent facets (50), the junctions (51) of the facets lying along a locus which has a radius of curvature which significantly exceeds the bend radius of the sheet material which would produce permanent deformation of the sheet material, the panel having longitudinally extending side edges each formed with a bead (14,16) having a radius of curvature sufficiently small to produce a permanent deformation of the sheet material. A cladding system for a building comprising a plurality of panels according to claim 7 and supporting means (26) mountable to hold said panels by engaging the longitudinal edges of said panels. A cladding system according to claim 8, characterised in that the supporting means (30) engage each of the panels internally of said longitudinal edges. A cladding system according to claim 8 or 9, characterised in that additional short lengths (412) of panel material are engaged over the panels at longitudinally spaced locations to give a patterned visual effect. A cladding system according to claim 10, characterised in that said additional short lengths (412) of panel material are formed of a different colour from the remaining panel material (410).

Inventors: LIM GUY HUMPHREY, LOUWERENS CORNELIS, RIJNDERS WILLEM, LIM, GUY HUMPHREY, LOUWERENS, CORNELIS, RIJNDERS, WILLEM
Applicants: HUNTER DOUGLAS IND BV, HUNTER DOUGLAS INDUSTRIES B.V.
Application year: 1990
Main classification: E04F13
IPC codes: E04F13, E04B9