Method and device for producing coated, and in particular painted, building boards and associated painted building board

Abstract

The subject matter of the present invention is a method for producing coated, and in particular painted, building boards (1), preferably for the interior finishing of buildings. First, the respective building board (1) is provided on its longitudinal edges (2) and/or transverse edges with a bevel (4). Then, the respective building board (1) is transferred to a rubber-like transporting belt (7) in such a way that the edges (2) respectively provided with the bevels (4) are arranged transversely in relation to the conveying direction (F) of the transporting belt (7) and the bevels (4) are arranged adjacent to a visible side (6) of the building board (1), facing away from the transporting belt (7). Finally, a coating material, and in particular paint (13), is applied to the visible side (6) of the building board (1) and respective bevel areas (5) of the bevels (4) in one operation with the aid of at least one roller (11) arranged above the transporting belt (7) and rotating substantially transversely in relation to the conveying direction (F).

Claims

1. A method for producing coated building boards for the interior finishing of buildings, with the following process steps: 1.1) the respective building board is provided on its longitudinal edges and/or transverse edges with a bevel; 1.2) the respective building board is transferred onto a rubber-like conveyor belt having a certain elasticity such that when pressed against the respective building board, a surface of the conveyor belt assumes a shape of the respective building board against which the surface of the conveyor belt is pressed, in such a way that the edges respectively provided with the bevels of the respective building board are arranged transversely in relation to the conveying direction of the conveyor belt and the bevels are arranged adjacent to a visible side of the building board and facing away from the conveyor belt; 1.3) a coating material is applied to the visible side of the building board and respective bevel areas of the bevels in one operation with the aid of at least one roller having an elasticity substantially equal to the elasticity of the conveyor belt, such that when pressed against the building board, a surface of the at least one roller assumes a shape of the bevels against which the at least one roller is pressed, wherein the at least one roller is arranged above the conveyor belt and rotating essentially transversely in relation to the conveying direction.

2. The method according to claim 1, characterised in that the building board is provided with the bevels at both its longitudinal edges in each case observing a bevel angle between 20 and 40.

3. The method according to claim 1 or 2, characterised in that the bevel area of the bevel is constituted flat or curved slightly outwards in a convex manner in cross-section.

4. The method according to any one of claim 1 or 2, characterised in that the rotating roller for applying the coating is provided with a flexible surface.

5. The method according to claim 2, wherein the bevel angle is between 30 and 35.

6. The method according to claim 4, characterised in that the rotating roller on the one hand and the conveyor belt on the other hand have elasticities in the range of 0.01 to 0.110.sup.9 N/m.sup.2.

7. The method according to claim 4, characterised in that the bevel area of the bevel is constituted flat or curved slightly outwards in a convex manner in cross-section.

8. The method according to claim 4, wherein the rotating roller for applying the coating is provided with a rubber coating.

9. The method according to claim 1, wherein the coating material comprises paint.

Description

(1) The invention is explained in greater detail below with the aid of a drawing merely representing an example of embodiment; in the figures:

(2) FIG. 1 shows the device according to the invention for producing coated building boards and

(3) FIG. 2 shows the building board produced according to the described method in the edge region in cross-section.

(4) A device for producing coated and in particular painted building boards 1 is represented in the figures. Building boards 1 in the present case are plasterboards 1, which have been produced from a board strand. For this purpose, the board strand has been cut in the transverse direction to the representation of respective longitudinal edges 2 of building board 1. No cardboard is consequently present in the region of longitudinal edges 2 on account of the cut edge there. Since building boards 1 are arranged edge to edge with their longitudinal edges 2, for example in the production of a drywall, the abutting region has to be processed in order to provide a flawless transition.

(5) For this purpose, the device is provided with at least one planing unit 3. As can be seen from the representation according to FIG. 1, two planing units 3 lying opposite one another and assigned to respective longitudinal edge 2 are in fact provided, said planing units being designed and equipped for providing respective building board 1 with a bevel 4 at its longitudinal edges 2.

(6) Bevel 4 is as usual an inclined surface at the edge of a workpiece, in the present case at longitudinal edge 2 of building board or plasterboard 1. With the aid of the two planing units 3 lying opposite one another, building board is thus tapered at its cut edges defining respective longitudinal edges 2. Bevel area 5 running along the bevel and longitudinal edge 2 thus arises.

(7) It can be seen that, within the context of the example of embodiment, and particularly preferably, bevel 4 is provided with a respective bevel angle between approx. 20 and approx. 40. Bevel angle is designed equal at both longitudinal edges 2. As usual, bevel angle is enclosed between bevel area 5 and a horizontal.

(8) In the example of embodiment, and as can be seen in FIG. 2, the horizontal is a visible side 6 or a plane of building board or plasterboard 1 parallel thereto. Bevel area 5 is constituted flat overall. In principle, bevel area 5 can however also have a shape curved (slightly) outwards in a convex manner in the represented cross-section according to FIG. 2, as is indicated by the dashed line in FIG. 2. According to a particularly preferred embodiment of the invention, bevel angle is located between 30 and 35.

(9) After respective longitudinal edges 2 of building board or plasterboard 1 have been tapered as described with the aid of the at least one or the two planing units 3, building board 1 is transferred onto a conveyor belt 7 or placed onto respective conveyor belt 7. Respective building board 1 is in fact transferred onto rubber-like conveyor belt 7 in such a way that the edges each provided with bevels 4 and in particular longitudinal edges 2 are arranged, according to the example of embodiment, transversely in relation to conveying direction F of conveyor belt 7. Moreover, the design is made such that building board 1 with its bevels 4 at visible side 6 or adjacent to visible side 6 of building board 1 are arranged facing away from conveyor belt 7. In the example of embodiment, the two bevels 4 of building board 1 running adjacent to visible side 6 each point upwards. In contrast, rear side 10 of building board 1 lies on conveyor belt 7.

(10) It can be seen that conveyor belt 7 is tensioned by two deflection rollers 8, 9 and is driven with the aid of deflection rollers 8, 9. As a result of this, building board or plasterboard 1 is transported in conveying direction F. At least one roller 11, which is arranged above conveyor belt 7, belongs to the further basic structure. In the example of embodiment, two rollers 11, 12 are in fact provided, which in the present case are constituted as application roller 11 and metering roller 12 upstream thereof and have an arrangement above conveyor belt 7. The two rollers 11, 12 form an upper gusset-like space filled with paint 13. A narrow gap between the two rollers 11, 12 ensures that paint 13 passes in the desired quantity onto paint application roller 11 and from there onto building board 1.

(11) Roller or application roller 11 rotates just like metering roller 12 in each case about an axis orientated essentially transversely in relation to conveying direction F, as corresponding arrows in FIG. 1 indicate. Moreover, the design is made in such a way that roller or application roller 11 and conveyor belt 7 together define between them a gap 14, through which building board of plasterboard 1 is passed for the purpose of coating. In the example of embodiment represented, a counter-roller 15 is also provided opposite application roller 11 and beneath conveyor belt 7, with the aid of which counter-roller conveyor belt 7 together with building board 1 conveyed through gap 14 is supported against the contact pressure on the part of the application roller 11.

(12) In the example of embodiment, with the aid of roller or application roller 11 arranged above conveyor belt 7 and rotating essentially transversely in relation to conveying direction F, paint 13 is applied in gap 14 not only on visible side 6 of building board 1, but also on respective bevel areas 5 of bevels 4 at longitudinal edges 2, and indeed in one operation. As a result of this, building board 1 thus provided with the respective coating has, after passing through gap 14, a paint coat or generally the coating applied in one operation on respective bevel 4 or its bevel area 5 and visible side 6.

(13) In order to enable this in detail, rotating roller or application roller 11 for the application of paint 13 is provided with a flexible surface 16 indicated in FIG. 1. This flexible surface 16 is a rubber coating of roller or application roller 11 in question. Conveyor belt 7, for its part, is constituted rubber-like. It has proved generally to be beneficial if rotating roller or application roller 11 on the one hand and conveyor belt 7 on the other hand have comparable elasticities. In the example of embodiment, the respective modulus of elasticity of rubber coating 16 as well as that of the material of conveyor belt 7 is located in the range from 0.01 to 0.01.Math.10.sup.9 N/m.sup.2. This applies of course only by way of example and is in general not imperative.

(14) It can be seen on the basis of FIG. 2 that building board 1 is provided in the thickness direction with a base area 1a and a bevel area 1b arranged above base area 1a. Base area 1a has a material thickness or thickness A. Bevel area 1b is provided with a material thickness or thickness B.

(15) The design is made overall in such a way that thickness B of bevel area 1b is less than half compared to thickness A of base area 1a. That is to say that the following applies:
B0.5 A.

(16) Usually, even the relationship B0.4 is met.

(17) It is thus ensured that bevel 4 of building board 1 extends only over a thickness region of building board 1 which amounts to 50% and less, in particular even 40% and less, of the thickness. The step associated with this can consequently be accommodated and compensated for without problem during the passage of building board 1 through gap 14 by, on the one hand, rubber coating 16 of roller or application roller 11 and, on the other hand, rubber-like conveyor belt 7. As a consequence of this, building board 1 is coated in one operation with paint 13 during the passage through gap 14 with the aid of rotating roller or application roller 11 both on visible side 6 and also in the region of its respective bevel areas 5 of bevels 4 at respective longitudinal edges 2. Any post-processing of bevel areas 5 is therefore not (no longer) necessary.

(18) In addition, there is the fact that respectively tapered longitudinal edges 2, when they are joined edge to edge to form a drywall for example, convey an optically uniform overall impression without any step changes or unevennesses. This is because the two bevels 4 or their bevel areas 5 accommodate visible side 6 located in between. Bevels 4 and visible side 6 have all been coated together and in one operation and have a coating of paint 13 applied in one operation. The main advantages are to be seen in this.