The present invention relates to a method for adjusting the shape of cassette-shaped plates for lining surfaces in a building, said plates comprising an essentially flat central portion and at least two folded and parallel side flanges, wherein the plates also comprise essentially parallel rows of weakening lines defined by the rows of through-going openings, said weakening lines extending essentially in parallel with the side flanges of the plate and essentially to their edges.

The present invention also relates to a plate of plastically deformable material for lining surfaces in a building, which plate is provided with at least two side flanges and also comprises a first set of essentially parallel rows of weakening lines defined by through-going openings, said weakening lines extending into the side flanges and essentially to their edges.

Ordinary cassette-shaped plates, also referred to as liner cassettes, that are used for lining internal building elements are often designed with a view to both aesthetic and an environmental considerations, and frequently the plates are provided with punched-out holes that impart good acoustic properties to the room in addition to constituting actual patterns,.

When eg ceilings are to be lined with liner cassettes, they may often exhibit several levels. Such ceiling in several levels can occur eg in those cases where, for the sake of incidence of light from a window, the ceiling is arranged further above the floor in the area adjoining the window. However, cablings or other installations may also entail that a part of the ceiling lining is to be lowered. Usually two different levels of a ceiling are connected by means of either pre- manufactured liner cassettes with fixed folds or by means of tailor-made liner cassettes manufactured in accordance with the customers' demands prompted by the task in question. This is both cumbersome and expensive.

It is the object of the invention to provide a method of adjusting the shape of cassette-shaped plates of plastically deformable material for lining the surfaces of a building, by which one may comparatively easily and inexpensively manufacture folded liner cassettes.

The method of adjusting the shape of cassette-shaped plates for lining surfaces in a building is characterised in that the side flanges of the plates are first cut open along one and the same weakening line and the flat central portion of the plates are then folded along the same weakening line.

Preferred embodiments will appear from independent claims 2-11.

It is also the object of the invention to provide a plate of plastically deformable material which is easily shaped on the installation site in order to thereby bridge several levels.

This is accomplished in that the plate comprises further holes that define a second set of essentially parallel weakening lines, which second set of weakening lines intersects the first set and extends into the side flanges and essentially to their edges; and that the distance between adjoining parallel rows of weakening lines is adapted to the distance between the through- going openings in the individual weakening lines, whereby the plates appear with a checkered pattern defined by the weakening lines.

According to one embodiment the plate is characterised in that the checkered pattern extends essentially in parallel with the side flanges of the plate. By that embodiment the plate is particularly suitable for folding perpendicular to its faces.

According to one embodiment the plate is characterised in that about 15% to 25%, preferably 15% to 25% of the area of the plate is constituted by openings. Thus, this configuration of the plate makes it possible to achieve actual weakening lines without compromising the requisite strength or the acoustic properties of the plate, including in particular its sound-deadening properties.

Configuration of the liner plates such that the distance between two weakening lines constitutes at least 6 mm and that the distance between the edges of the openings in a weakening line constitutes maximally 4 mm, a plate is accomplished that have both particularly advantageous acoustic and static properties.

According to one embodiment the plate is configured with folded side flanges that comprise attachment means. By providing the side flanges with attachment means the liner cassettes can be mounted in eg a rail system.

According to one embodiment the plate is configured with folded side flanges that comprise at least one bead preferably drawn into a weakening line. By providing the side flanges with one or more beads the liner cassettes can be mounted in a rail system in that one or more of these beads are clicked into engagement with a flexible rail. The position of the beads in the weakening lines accomplishes that tension around the beads will, rather than transplanting to the top face of the plate, be absorbed locally in the weakening lines.

According to one embodiment the plate is configured in that the side flanges are produced by folding along a weakening line. Such configuration of the liner cassette accomplishes that two ceiling cassettes, assembled in a rail system, may appear with a very homogenous pattern, since those parts of the openings in the folding of the side flanges that are visible from the top face of the plate, can be assembled in an apparently complete perforation row.

According to one embodiment the plate is provided with a sound-deadening layer of non-woven material, eg in the form of acoustic nonwovens.

Configuration of the plate as a plate with outer dimensions of essentially 600 mm by 600 mm or 625 mm by 625 mm it is accomplished that the liner cassette has standard dimensions.

By the weakening lines constituting one single row of openings, a strong liner cassette is accomplished which is simultaneously easily deformed along the weakening lines.

Configuration of the liner cassette with weakening lines essentially configured in a checkered pattern, where the distance between the weakening lines constitutes a divisor of the side length of the liner cassette, it is accomplished that the side flanges can be folded along weakening lines and also that a portion of the plate can be cut off and new side flanges be folded along a weakening line.

Configuration of the liner cassette with weakening lines essentially in a checkered pattern where the centre distance between the weakening lines constitutes a divisor of the side length of the ceiling plate, and the centre distance between the openings in the individual weakening lines also constitutes a divisor of the distance between the lines it is also accomplished that the openings can occur symmetrically around the individual checks. The invention will now be explained in further detail with reference to the drawings, wherein

Figure 1 shows a ceiling exhibiting a raised portion at a window element;

Figure 2 shows a liner cassette, in a perspective view;

Figure 3 shows an assembled and folded ceiling plate system;

Figure 4a shows a corner portion A of the liner cassette shown in Figure 2 with bead in the side flange;

Figure 4b shows a corner portion of a liner cassette wherein the side flanges 8 comprise a folding along a weakening line;

Figure 5a shows two side parts as shown in Figure 4a assembled by means of a flexible rail; and

Figure 5b shows a joining of two side parts as shown in Figure 4b by means of a T-rail.

Ordinary liner plates 10 that are used for lining ceilings or other building elements are often designed both from an aesthetic and an environmental aspect; and frequently the liner plates are configured with punched openings that also impart good acoustic properties in addition to constituting actual patterns.

The liner plate 10 as such may be a so-called liner cassette, ie a cassette with at least two folded side flanges 8 as shown in Figures 2 and 4a. Ceilings that are to be lined with liner cassettes may often exhibit different levels. Such multi-level ceiling is shown in Figure 1 , where - for the sake of light incidence from a window 40 - the ceiling exhibits a higher level 20 in the area adjoining the window. Likewise the cablings or other installations may also involve that a part of the ceiling is to be lowered. Usually two different levels of a ceiling are connected by means of either pre-manufactured lining plates with fixed foldings or by means of tailor-made liner plates manufactured in accordance with customers' demands prompted by the task in question. Those tailor-made liner plates are very expensive as they are produced in a separate process; in particular tailor-made liner cassettes may. be cost- intensive as the side flanges make particular requirements to the configuration.

There is therefore a need for a novel method and novel plates that enable accurate shaping of the plates on the installation sites and hence bridging of different levels.

As mentioned previously, liner plates are often perforated and this is due to both aesthetic and practical considerations, since - in addition their appearing as patterns - the perforations also provide the space in which the plates are arranged with improved acoustic properties. Experience has shown that a perforation degree of about 20 % (ie where approximately 20% of the overall exposed area of the plate is constituted by openings) impart good acoustic properties to liner plates.

Thus it has been found that a local increase in and a corresponding reduction of the degree of perforation may occur without compromising the acoustic properties of the plate, including first and foremost its sound-deadening performance. Surprisingly, it has been found to require only that the overall degree of perforation of the plate be kept within the range usually necessary for obtaining given acoustic properties. Thus the invention realizes that it is possible in a plate with acoustic properties to concentrate the perforations in actual rows, wherein the strength of the plate is thus reduced considerably. In the following, these rows of perforations are designated weakening lines 6. By letting the weakening lines 6 extend transversally of the folded-up side flanges 8 and essentially in a checkered pattern extending all the way to the edge 9 thereof, a plate is accomplished that features - in addition to preserved acoustic properties - a central portion 50 which can easily and accurately be folded along these distinct weakening lines. Since the side flanges 8 of the plate also appear with distinct weakening lines 6, the shaping most often takes place by them being first cut up by means of ordinary hand tools, such as pliers or the like, following which the central portion is folded. As it is, the term "cut" is not intended to designate that scissors or pliers need to be used; the most important being that the material between the openings is broken, and to that end numerous different tools can be used.

The invention has further been found to enable that perforated liner cassettes achieve optimal acoustic and strength properties by a perforation degree of about 15% to 25%. This means that about 15 % to 25 % of the thus exposed overall area of the plate is constituted by openings.

A liner cassette may have a perforation as shown in Figure 4a.

The liner cassette is manufactured from a plastically deformable material, such as steel or other metal, but in principle any other plastically deformable material can be used. The lines in which the perforations occur with the smallest distance constitute predominant weakened areas, and therefore - as mentioned above - they are designated weakening lines 6. The perforations have such size and mutual distance that they exhibit an essentially rectilinear course. In the figures, the perforations are shown as round openings, but they may just as well have many other shapes such as oval, quadrangular or triangular. The shortest possible distance between two openings is called the opening distance b, d and constitutes, as will appear from Figure 4a, the distance from opening periphery to opening periphery (or edge to edge in openings that have other shapes than round) between neighbouring holes/openings, in a weakening line 6. Conversely the central distance is defined as the distance from centre to centre between neighbouring openings/apertures. The distance c, e as shown in Figure 4a is defined as the distance between similarly positioned points in two weakening lines/perforation rows 6, which thus also means the distance from the centre (the centre of the openings) in one weakening line/perforation row to the centre (centre of the openings) in the next one.

In order to improve the sound deadening properties of the liner cassette, the side of the liner cassette that does not have to be visible can be provided with a layer of non-woven material, eg carbon fibres or acoustic nonwovens.

The liner cassette 10 as such is, as mentioned above, a so-called ceiling cassette. That is a liner cassette with at least two side flanges 8 as shown in Figures 2 and 4a. In order to ensure that the plate 10 can be assembled in eg a continuous rail system, the corners of the plate can moreover be provided with one or more cutouts 3 as shown in Figure 4a and 5a. These cutouts that are called "sviks" (cutout providing room for accomodating rail) may extend on the one or both sides of the individual corners.

For the sake of mounting by means of an already known flexible rail system 15, the side flanges 8 may, as will appear from Figure 4a, be provided with beads 11. The mounting of such liner cassette in the rail system 15 takes place in that one or more of such beads is/are clicked into engagement with the flexible rail 15 that is shown in Figure 5a. In the prior art liner cassettes the beads in the flanges 8 are created by the material being drawn upwards. However, it has been found to present drawbacks in that the thus created local tensions in the plate will, in time, transplant to visible deformations on the front 50 of the plate. By arranging the beads 11 preferably in a perforation row 6, as shown in Figure 4a, it is accomplished that instead of transplanting to the top side of the plate, these tensions are absorbed locally in the weakening/(line) constituted by such perforation row 6.

For suspension in another rail system 14 as shown in Figure 5b, the liner cassette can also be configured with side flanges 8 as shown in Figure 4b. These side flanges comprise a fold 12 that may be performed in a weakening line 6. That configuration of the liner cassette achieves that the liner cassette can be suspended in a simpler kind of suspension rail 14 which is also shown in Figure 5b. That suspension rail comprises at least one flange 13 or the like on which the fold 12 can rest.

In the shown examples the liner cassettes are kept together by means of the rail systems as such, but the liner cassettes could in principle be held together in other ways, eg by means of clips or the like. The perforations in eg the side flanges 8 could also constitute a part of the attachment means by serving as holes for screws, nuts or the like attachment means.

When a liner cassette 10 is to be mounted such as to connect two different levels as outlined in Figure 3, wherein it is desired to conceal two tubings 4 and 5, the side flanges 8 must first be separated along the weakening line 6 (which is constituted by one single perforation row in the figures) along which the central portion 50 of the plate is to be folded. Due to the deteriorated structure in the weakening line, this is easily accomplished by means of a hand tool, such as eg pliers or the like. As also outlined in Figure 4a, it may also be advantageous to remove or fold an adjoining piece 7 in those cases where the folding is to be performed towards the rear of the plate.

By configuring the liner cassette with weakening lines essentially configured a checks with sides that are in parallel with the sides of the plate, and wherein the centre distance c,e between the weakening lines constitutes a divisor of the side length E of the ceiling plate, it is accomplished both that the perforation pattern can occur evenly distributed across the plate and that the side flanges 8 can be folded along a weakening line 6. In a liner cassette where the checks are moreover and essentially rectangular, this construction enables folding of the liner cassette along not just one or two, but several weakening lines that may also be perpendicular. A plate structured and folded like this could be assembled with other plates having corresponding patterns and form faces where the perforation pattern has a very even course.

By configuring the liner cassette with weakening lines configured essentially in a checkered pattern with sides that are parallel with the sides of the plate, and wherein the distance c,e between the weakening lines constitutes a divisor of the lateral length E of the ceiling plate, and wherein the centre distance between the openings in the individual weakening lines also constitute a divisor of the line distance c,e, it is accomplished that the openings are further able to appear symmetrically around the individual checks. As will also appear from Figure 4a, the side flanges 8 are produced by folding along a weakening line 6. This means that a part of the openings in the weakening line along which the side flanges have been folded are drawn into the side flange 8 and a part has remained visible on the top face 50 of the plate. A plate structured and folded like this can be assembled with other plates having corresponding patterns and combine to form a lining face, wherein the perforation pattern extends very evenly. Moreover, it can be shortened along a weakening line and still be joined with corresponding plates in joints that resemble one single perforation row. It could also be folded along several weakening lines and still be joined with other plates in joints that blend in with the homogeneous perforation pattern enabled by those plates.

By configuring the perforations in the liner cassette as rows of openings having a diameter of 2.2 mm, wherein the rows have a mutual distance (centre-to-centre or c,e) of 12.5 mm., and the openings of the individual rows are arranged with a mutual centre distance of 3.125 mm, a degree of perforation very close to 20 % is accomplished. By said perforation it is also accomplished that liner cassettes with a side length E of both 600 mm by 600 mm or 625 mm by 625 mm could be produced such that the side flanges 8 of the ceiling cassette can be folded along rows of weakening lines 6 as shown in Figures 4a-b.

By configuring the perforations in the liner cassette as rows of openings having a diameter of either 1.6 mm, 1.7 mm or 1.8 mm, wherein the rows have a mutual distance of 10 mm, and the openings of the individual rows are arranged with a mutual centre distance of 2.5 mm, a perforation degree very close to 20 % is also obtained, wherein the weakening lines 6 are even more distinct. By said perforation it is also accomplished that liner cassettes having a side length E of both 600 mm by 600 mm could be produced such that the side flanges 8 of the ceiling cassettes can be folded along rows of weakening lines 6, as shown in Figures 4a-b.

The liner cassette and its pattern according to the invention are usually configured to be rectangular or square, but other shapes are also possible; for instance the plates or their pattern may just as well be triangular or pentagonal.