Façade covering made of embossed metal sheet

Abstract

The present invention relates to specially embossed metal profile sheets which, due to positive and negative embossing, have a multitude of knob-like protrusions and depressions on both their upper and lower surfaces. The profile sheets have an approximately sinusoidal cross-sectional edge and a maximum cross-sectional height of 0.75 to 21.5 mm, achievable with raw metal foils of a thickness of 0.05 to 0.85 mm, particularly 0.1 to 0.75 mm, preferably 0.2 to 0.65 mm. They exhibit unexpectedly high torsional and deformation stiffness and are therefore suitable for use as decorative and functional facade elements, especially for the external cladding of building facades.

Description

TECHNICAL AREA

[0001] The present invention relates to specially embossed, torsionally rigid profiled metal sheets and their use as functional and decorative covering elements for the external cladding of objects, in particular building facades. STATE OF THE ART

[0002] Profiled metal sheets used as roofing or wall elements are known in the art. These are usually rolled corrugated or trapezoidal sheet profiles made of aluminum or various metal alloys. Embossed metal sheets are also known, their profile structures being produced by hammering, pressing, or using rollers with raised bumps. For example, Australian patent AU 2019261 740B2 shows such an embossed sheet as part of a sandwich structure for use as a curtain panel for cladding building facades.

[0003] Many of these embossed profiled sheets have in common that they are only embossed on one side, meaning they have a structured first surface and a substantially smooth second surface. For example, a top surface with raised features protruding from the plane of the sheet, such as bumps of any geometric shape, and a substantially smooth underside that appears flat in cross-section, with the indentations created by the bumps. All the bumps on such an embossed sheet can have the same shape and size, or they can have different shapes and / or sizes. The spacing between the bumps can also vary as needed.

[0004] Since the smooth and profiled metal sheets used today as facade elements on high-rise buildings worldwide serve practically exclusively decorative purposes, material thicknesses of 0.9 - 2 mm are typically used for such sheets in order to reliably and with sufficient reserve meet the mechanical properties required in country-specific building regulations with regard to torsional stiffness, compressive and tensile strength, pull-out strength and the like.

[0005] Another reason for choosing thicker material for facade panels is that practical experience has shown that some of the mainly smooth, unembossed panels, when used for large-area cladding of building facades, develop unsightly, wavy deformations over time. BRIEF DESCRIPTION OF THE INVENTION

[0006] In contrast, the present invention utilizes the insight gained during product development that double-sided embossing of metal sheets (i.e., positive and negative embossing) can successfully overcome the aforementioned disadvantages. In particular, it has been shown that with double-sided embossed metal foils or sheets, the desired strength parameters, or those required by the relevant building regulations, can be achieved with significantly reduced material thicknesses compared to commercially available, unembossed sheets and metal foils of the same material composition. This allows for a reduction of the commonly used sheet thicknesses for facade cladding from approximately 0.9–2 mm to less than 0.9 mm, and in particular to 0.05–0.85 mm.

[0007] Furthermore, the profiled sheets according to the invention, which are positively and negatively embossed, are extremely torsionally rigid and, with typical sheet panel sizes ranging from approximately 0.5m x 1m to approximately 2m x 5m, remain perfectly flat after proper installation, without ever developing any wavy deformations. The significantly reduced costs resulting from the material savings make this type of facade cladding affordable and attractive even for private users.

[0008] The inventive, double-sided embossed profiled sheets can give a highly elegant, modern look to small and large building facades, or parts thereof, especially when the profiled sheets are additionally provided with paints, varnishes or special coatings.

[0009] Another positive aspect of this double-sided embossed structure with optionally painted or coated surfaces is demonstrated in practice by the fact that the facade panels produced in this way according to the invention are largely free of glare and mirror effects, which benefits both the installers during the installation of the facade panels, as well as passers-by walking along such facades, residents of buildings opposite, and also wild animals such as birds.

[0010] In a preferred manufacturing process, the double-sided positive / negative embossing of the metal sheet or metal foil, which is typically supplied as roll stock, is carried out analogously to a classic wide-band profiling process, but using two interlocking tools with embossing bumps or embossing teeth of the desired shape, size and arrangement.

[0011] In this context, the term "bumps" refers to a plurality of raised areas or protrusions, typically in a regular arrangement, protruding from the surface of a tool or a machined metal foil. FIGURE DESCRIPTION

[0012] The structure of the metal sheets embossed according to the invention is schematically illustrated in the figures. Fig. 1 shows a schematic diagram of a studded sheet metal element according to the invention in a top view; in this exemplary embodiment, the studs are arranged at regular, constant intervals in horizontal and vertical, parallel rows, with each second horizontal or vertical row of studs being offset from the previous horizontal or vertical row by half the distance between two adjacent stud tips in the vertical or horizontal direction; the circles show the raised areas, the empty areas between them the depressions; the cut edges along the cutting axes AA (a) and BB (b) each have an approximately sinusoidal wave shape; the dimensions are in mm; the tips of the raised areas and depressions have a spherical shape with a spherical radius of 1.5 mm and a spherical spacing, measured from tip to tip, of 7.3 mm, and an opening angle of 86.5 degrees, spanned by two tangents applied to opposite side walls of a protrusion or depression; the cross-sectional height of the embossed sheet in this example is 3 mm, achievable with metal foils of 0.2 mm thickness at an embossing ratio of 1:15 or of 0.12 mm thickness at an embossing ratio of 1:25. Fig. 2: shows a schematic representation of a sheet embossed on both sides according to the invention in an oblique view from above, with an approximately sinusoidal cut edge; the original plane of the unembossed metal foil is indicated by dashed lines. Fig. 3: shows a section of a foil embossed according to the invention in a top view, with light protrusions and dark depressions as well as a corresponding cross-sectional view of the cut edge; in this embodiment, the distances between two vertically or horizontally adjacent protrusions (measured from tip to tip) are 7.3 mm, between two diagonally adjacent protrusions (or depressions) 5.16 mm, and from the center of a protrusion to the center of the adjacent depression 3.65 mm; a: the protrusions and depressions have tips in the form of spherical shells (caps) with a cap radius R = 1.5 mm; the total cross-sectional height of the embossed metal foil, measured from the highest point of the tip of a protrusion to the lowest point of an adjacent depression, is 3 mm in this example, and the opening angle, defined by two tangents drawn to opposite side walls of a protrusion or depression, is approximately 71 degrees. Fig. 4 shows how. Fig. 3 a section of a foil embossed according to the invention in top view, with light elevations and dark depressions: a in enlarged view (circular section) with dimensions in mm (a); and b a section of an embossed sheet in top view, at an approximately real scale of 1:1. DETAILED DESCRIPTION OF THE INVENTION

[0013] The profiled sheets according to the invention, intended for cladding a wide variety of objects, in particular for cladding the facades of modern residential or industrial buildings, are profiled from flat-rolled metal foils, usually in the form of rolls, typically made of aluminum, stainless steel, or another metal alloy, into so-called semi-finished products. These semi-finished products can be manufactured as cut pieces in the desired shape or, where technically feasible, as rolls.

[0014] In a first step, the manufacturing process of known wide-band profiling is applied. This process is specifically designed to multiply the inherent stiffness of a raw metal foil while maintaining the same foil thickness. The profiling process applied according to the invention also does not change the wall thickness of the metal foil, but increases its inherent stiffness to an unexpectedly high degree through targeted deformation. Furthermore, it saves material thanks to the reduced thickness of the raw metal foil material, thus opening up additional processing possibilities.

[0015] The profiling process is technically comparable to the production of corrugated or trapezoidal profiles for the construction industry. The core component of every profiling system is the profiling tool, also known as a profiling die. Its design is based on the rolling technology used for wide strip profiling. The die tools are equipped with embossing teeth or embossing studs, which can, in principle, have any geometric shape. According to the invention, these embossing teeth or studs are preferably designed as small three- or four-sided pyramids or as cones, each with rounded, spherical tips, so that a double-sided, positive / negative profile structure is created in the form of spherical caps (spherical shells) projecting from the plane of the metal foil. Fig. 2 In cross-section, this results in an approximately sinusoidal wave structure that extends below (negative embossing) and above (positive embossing) the original plane of the metal foil ( Fig.1 a, Fig. 2 , Fig. 3a ). However, due to the process or tooling, small distances must be maintained between adjacent embossings, so that the distance between two vertically or horizontally adjacent stud tips is slightly larger than twice the maximum diameter of a stud at its base ( Fig. 1 ).

[0016] The closed and open caliber tools, specially developed for producing the embossing profile according to the invention, enable the metal foil to be fed in both transversely and longitudinally to the material flow direction of the metal foil in the embossing system.

[0017] In this process, the shape of the raw metal foil is changed in several steps, both lengthwise and crosswise to the material flow direction of the foil, within the embossing machine, in order to improve its stiffness, assembly, and further processing. However, the material composition, surface finish, and thickness (foil thickness) of the raw metal foil material, which is usually delivered as roll stock from a rolling mill, remain unchanged.

[0018] The embossed end product thus exhibits a substantially uniform material cross-section and technically corresponds to a corrugated profile with double profiling, namely longitudinally and transversely to the direction of travel of the metal foil in the profiling machine. The positive / negative embossing according to the invention not only significantly improves the inherent stiffness of the material, but also, by increasing the inherent stiffness, significantly improves its resistance to pull-out forces, i.e., its pull-out stability. A further significant advantage is the resulting improvement in the elongation behavior of the embossed material, which leads to a considerable extension of its service life, especially in the case of facade panels according to the invention that are exposed to increased wind loads.

[0019] The nubs are applied in parallel rows, one behind the other and next to each other, as shown in the illustrations ( Fig.1, Fig.2 , Fig.3 and Fig.4 ) shown, wherein the studs of two immediately adjacent rows are preferably offset from each other by half the distance between two stud tips arranged in a vertical or horizontal direction (= slightly more than a maximum stud width at their base), resulting in a "gap-spaced" arrangement of the studs in the direction of travel and transversely to the direction of travel of the embossed film web, as can be seen from the illustrations. In the cross-section of a metal sheet embossed according to the invention, the cut edge ( Fig.1 b , c; Fig.3 a ) the approximately sinusoidal wave profile of the positive / negative embossing with wave crest (bump) and wave trough (corresponding depression) is recognizable, and behind each wave trough of the cut edge (= first row) the wave crest or bump of the second row of bumps is arranged immediately behind it, offset by half a period. It is preferred to position the protrusions and depressions such that, in a top view, the rows of protrusions, as well as the rows of depressions, are arranged diagonally at an angle of 45 degrees to the direction of travel or feed of the metal foil in the profiling machine, as shown in Fig.1 , Fig. 3 and Fig. 4 depicted.

[0020] The best results in terms of torsional stiffness and material savings are achieved with dome-shaped embossed patterns when... a) the distance – when viewed from above – between two adjacent nub or cap tips in a vertical or horizontal direction is 3–25 mm, preferably 6–12 mm, and particularly approximately 7.3 mm; and / or b) the distance between two adjacent nubs in a diagonal direction, measured from nub tip to nub tip, is 2.5–10.0 mm, preferably 3.5–6.0 mm, and particularly 5.2 mm; and / or c) the opening angle spanned by the tangents of two opposing side walls of a recess or protrusion is 60–90 degrees, particularly 70–88 degrees, and the cap radius is 0.5–5 mm, preferably 1–3 mm, and particularly 1.5–2 mm.

[0021] The embossing depth cannot be chosen arbitrarily. The embossing ratio of the thickness of the unembossed metal foil to the maximum cross-sectional height of the embossed metal foil is therefore preferably in a range of 1:15 to 1:25 for the profiled sheets according to the invention. Fig. 1With a metal foil 0.05 mm thick, a maximum cross-sectional height of 0.75 mm (at a 1:15 dilution) or 1.25 mm (at a 1:25 dilution) of the embossed end product can be achieved before any painting or coating, depending on the material composition of the metal foil. Alternatively, with a raw metal foil thickness of 0.7 mm, a maximum cross-sectional height of 10.5 mm or 17.5 mm of the embossed profiled sheet can be achieved. The thickness of the metal foil or metal sheet used for embossing according to the invention is therefore typically in the range of 0.05 to 0.85 mm, with a thickness of 0.1–0.75 mm being preferred, and a thickness of 0.2–0.65 mm being technically sufficient and usually also the most cost-effective for most applications. Accordingly, the cross-sectional heights of the metal foils or sheets embossed according to the invention are in a range of 0.75 - 21.25mm, typically from 1.5 - 10mm and preferably from 2 - 5 mm.

[0022] The embossed aluminum-based metal sheets can be anodized, colored, painted, and / or powder-coated for outdoor applications. Anthracite gray or black coated, embossed aluminum sheets according to the invention, when used as facade cladding, result in a homogeneous and glare-free appearance, while simultaneously exhibiting high deformation and torsional rigidity of the individual facade sheet elements.

[0023] Metal sheets stamped according to the invention, based on stainless steel or other metal alloys common in the prior art, can also be colored and / or coated as desired in order to meet different customer requirements.

[0024] The embossed metal sheets according to the invention can be used and installed in smaller units for cladding building envelopes or parts thereof, such as balcony railings, in skeleton construction, as well as for large-area, multi-story facade cladding and as curtain walls. They fulfill a protective function against weather influences on the building envelope, an energy-saving function in the cold season, and, above all, a representative, visual function to showcase a building envelope as desired.

[0025] Even from a distance of approximately 5 meters, the raised bumps of a vertically positioned facade panel according to the invention are no longer recognizable as such, and the facade panel therefore appears uniformly flat and smooth, with a glare- and reflection-free, matte-looking surface. When viewed from other angles or perspectives, this effect occurs even at shorter viewing distances, which offers a significant advantage for installers on construction sites, for passersby walking past building facades clad with such panels according to the invention, and also for residents of buildings opposite, who might otherwise be blinded by a smooth, metallic facade. The positive effect on birds should also not be underestimated; thanks to the glare- and reflection-free nature of the facade elements according to the invention, they can recognize the facade as an obstacle in time and react accordingly.

Claims

1. Flat, torsion-resistant profiled sheet metal for use as a covering element in building construction and civil engineering, in particular as a facade element for cladding the exterior walls of buildings, characterized by the fact that It is made of a metal foil with a thickness of 0.05 - 0.85mm, in particular of 0.1 - 0.75mm, preferably 0.2 - 0.65mm, and has a plurality of knob-shaped protrusions and depressions on both its top and bottom surfaces due to positive and negative embossing, wherein the profiled sheet has an approximately corrugated cross-section with a maximum cross-sectional height of 0.75mm - 21.25mm, typically of 1.5 - 10mm and preferably of 2 - 5mm.

2. Flat, torsionally rigid profiled sheet according to claim 1, characterized by the fact that The knob-shaped bumps and depressions on both sides of the metal foil surface are arranged regularly in horizontal and vertical rows at regular intervals.

3. Flat, torsionally rigid profiled sheet according to claim 1 or 2, characterized by the fact that The knob-shaped bumps and depressions are arranged in parallel rows with a phase shift relative to each other, so that the bumps of a directly adjoining second row are located at the locations of the depressions of a first row.

4. Flat, torsionally rigid profiled sheet according to one of claims 1 to 3, characterized by the fact that the distance between two adjacent studs in a horizontal or vertical direction, measured from stud tip to stud tip, is 3 - 25mm, preferably 6 - 12mm, and particularly 7.3mm.

5. Flat, torsionally rigid profiled sheet metal according to one of claims 1 to 4, characterized by the fact that The distance between two diagonally adjacent studs, measured from stud tip to stud tip, is 2.5 - 10mm, preferably 3.5 - 6mm, and particularly 5.2mm.

6. Flat, torsionally rigid profiled sheet according to one of claims 1 to 5, characterized by the fact that an opening angle spanned by tangents to opposing side walls of a depression or elevation is 60 - 90 degrees, in particular 70 - 88 degrees.

7. Flat, torsionally rigid profiled sheet according to one of claims 1 to 6, characterized by the fact that the knob-like elevations and depressions are rounded at their tips in a calotte shape and have a calotte radius of 0.5 - 5mm, preferably 1 - 3mm, and particularly 1.5 - 2mm.

8. Flat, torsionally rigid profiled sheet according to one of claims 1 to 7, characterized by the fact that It is anodized, painted and / or coated.

9. Use of a flat, torsionally rigid profiled sheet according to one of claims 1 to 8 as a covering element for exterior surfaces in building construction and civil engineering, in particular as a facade element for the functional and / or decorative cladding of building facades or parts thereof, in private and commercial building construction.

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