Appliance and method for surface treatment of a board shaped material and floorboard

Abstract

A device for coating surface portions of a board material with a liquid material. The device includes a wheel which transfers the coating material and compressed air which positions the coating material. A method for surface coating and a floorboard with a finished surface portion.

Claims

1. A device comprising: a machining device which removes the top layer of a building panel in order to obtain a machined surface portion, the machined surface portion comprising core material of the building panel; a container for containing a liquid coating material; a coating wheel having a main plane and an outer edge wall extending in a direction other than in the main plane such that the outer edge wall faces radially outward from the coating wheel, said coating wheel being arranged so as to obtain the liquid coating material from the container and transfer the liquid coating material via surface tension from the outer edge wall of the coating wheel to the machined surface portion by a rotary motion, to obtain a coating which covers said machined surface portion; and a positioning device for positioning of the building panel relative to the coating wheel; wherein the coating wheel is positioned below the machined surface portion.

2. The device of claim 1, wherein the positioning device comprises chains and bands.

3. The device of claim 1, wherein the machining device removes an edge portion of the top layer of the building panel such that the machined surface portion is an edge of the sheet-shaped blank.

4. The device of claim 1, wherein the machining device removes a groove portion of the top layer of the building panel such that the machined surface portion is a groove in the sheet-shaped blank.

5. The device of claim 1, wherein the machining device is configured to remove a laminate top layer material from an HDF core material.

6. The device of claim 1, wherein the machining device is configured to remove a plastic, linoleum or rubber top layer material from an HDF core material.

7. The device of claim 1, wherein the machining device is configured to remove a wood or wood veneer protected with one or more layers of oil or varnish top layer material from a wood or wood fiber core material.

8. The device of claim 1, wherein the machining device is configured to remove a protecting layer of oil or varnish top layer material from a massive wood core material.

9. The device of claim 1, wherein the coating wheel is configured to apply a pigmented oil coating material.

10. The device of claim 1, wherein the coating wheel is configured to apply a liquid coating material comprising pigments, a binder and a viscosity-reducing agent.

11. The device of claim 1, wherein the coating wheel is configured to apply a liquid coating material comprising organic pigments, vegetable alkyds and mineral oil.

12. The device of claim 1, wherein the coating wheel is adjustable relative to the building panel at a vertical or horizontal angle.

13. The device of claim 1, wherein container comprises a first and second container, and wherein the liquid coating material is circulating between the first and second container to obtain a correct amount of liquid coating material in the first container supplied to the coating wheel.

14. The device of claim 1, wherein a part of the coating wheel is arranged to rotate in the container.

15. The device of claim 1, wherein the container is positioned below the building panel.

16. The device of claim 1, wherein the coating wheel has an application surface that transfers the liquid coating material directly onto the machined surface portion, and the application surface of the coating wheel is positioned below the machined surface portion.

17. The device of claim 1, wherein the entire coating wheel is positioned below the machined surface portion.

18. The device of claim 1, further comprising an air system arranged downstream of the coating wheel, the air system configured to remove excess liquid coating material from a top surface of the building panel.

19. The device of claim 14, wherein the container includes the liquid coating material.

20. A device comprising: a machining device which removes the top layer of a building panel in order to obtain a machined surface portion, the machined surface portion comprising core material of the building panel; a coating wheel having a main plane and an outer edge wall extending in a direction other than in the main plane such that the outer edge wall faces radially outward from the coating wheel, said coating wheel being arranged so as to transfer a liquid coating material directly from the outer edge wall of the coating wheel to the machined surface portion by a rotary motion, to obtain a coating which covers said machined surface portion; and a positioning device for positioning of the building panel relative to the coating wheel; wherein the coating wheel is positioned below the machined surface portion, further comprising an air system arranged downstream of the coating wheel, the air system configured to remove excess liquid coating material from a top surface of the building panel, wherein the air system includes a compressed air nozzle disposed proximal to the top surface of the building panel, said compressed air nozzle directing the excess liquid coating applied to the top surface toward the machined surface portion of the building panel, wherein when in use, the coating wheel transfers the excess liquid coating to the machined surface portion and to at least part of the top surface of the building panel, and the compressed air nozzle applies air to the top surface so as to move at least the excess liquid coating applied to the top surface in a contactless manner using an air flow, and when in use, the air nozzle applies air in a direction substantially parallel to the top surface of the building panel and towards the main plane of the coating wheel.

21. The device of claim 1, wherein the coating wheel is moved vertically and/or horizontally with respect to the building panel as the positioning device moves the building panel past the coating wheel at a feeding speed.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIGS. 1a-b show a device for coating of board material.

(2) FIGS. 2a-c show examples of coating of different surface portions in a floor with a mechanical locking system.

(3) FIGS. 3a-b show examples of coating with excess paint which is sprayed away from the surface.

(4) FIGS. 4a-c show coating by means of a plurality of wheels.

(5) FIGS. 5a-b show the embodiments according to FIGS. 2a and 2c enlarged

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

(6) FIG. 1a shows a device according to an embodiment of the invention, for coating a surface portion of sheet-shaped blank 1, comprising a core 30 and a top layer 31, seen parallel to the direction of travel of the board and FIG. 1b shows the device seen perpendicular to the direction of travel of the board.

(7) The sheet-shaped blank, for instance a floorboard 1 with a top layer, is driven preferably through a machining line horizontally in a direction D. In this embodiment, the floorboard 1 is oriented with an unmachined surface of the top layer 31 downwards. A machined surface portion 21, with the top layer removed touches a wheel 2, which rotates in the direction of travel R of the floorboard by means of a driving device 8. The wheel 2 is rotated at the same peripheral speed as the speed of feeding of the floorboard 1. The driving device 8 can rotate the wheel 2 at different speeds, preferably between 10 and 200 m/min. A suitable speed in connection with manufacture of floors is about 60-130 m/min. Using suitable chemicals, wheel diameters and materials selected for the wheel 2, high speeds of up to 200 m/min can be achieved without the coating material leaving the wheel. A suitable wheel diameter is 120-200 mm. The wheel can be provided with a freewheel so that any difference in speed between the board 1 and the wheel 2 can be leveled out. The width of the wheel portion W, which transfers the coating to the sheet-shaped blank, is preferably smaller than the width of the sheet-shaped blank and preferably in the range of 0.1-20 mm.

(8) The wheel 2 is coated with a liquid material 6, such as pigmented oil, varnish, paint, wax, glue and the like, in a container 6 which preferably has a splash guard. The container can be provided with an inlet, a discharge and an overflow tube 11 for returning purposes. The coating wheel 2 has a main plane 201 and an outer edge wall 202 extending in a direction other than in the main plane 201 such that the outer edge wall 202 faces radially outward from the coating wheel 2.

(9) In order to obtain the correct amount of coating material 6 on the wheel 2 there is preferably a scraper, which can be controlled and locked by a micrometer. It should be possible to adjust the wheel 2 with great accuracy relative to the board at an angle as well as vertically and horizontally. This is suitably performed by means of a turnable coordinate table 9. In FIG. 1a the wheel has an angle of about 10 degrees to the vertical plane. Suitable angles for coating of beveled edges are 0-45 degrees. A pump 7 can be used to continuously circulate the liquid coating material 6 via a filter.

(10) A photocell, a mechanical device or the like can be arranged to activate a compressed air system with a nozzle 3 which blows excessive coating material away from the unmachined surface of the top layer 31 by an air flow A. Excessive material blown away by compressed air can be caught in a container 10 provided with a filter. The equipment can be provided with a PLC (Programmable Control System) controlled automatic cleaning system. The device allows coating with narrow tolerances. For instance, coating can be performed with an accuracy of about 0.1 mm in relation to the unmachined surface of the top layer. Optimum results are achieved preferably if the floorboard is correctly positioned relative to the wheel. This positioning can take place in the machining unit by means of, for instance, chains and bands, or when the floorboard leaves the machining unit 16 by means of rules and pressing rollers. To achieve great accuracy it is also preferable for the wheel 2 to have essentially the same peripheral speed as the floorboard. It is advantageous if the difference in speed is less than 10 m/min. For a good result, it is not necessary for the wheel 2 to touch the floorboard. The coating material is transferred to the floorboard by surface tension.

(11) FIG. 2a illustrates coating of a decorative groove 21 which is substantially parallel to the surface of the top layer 31. In this embodiment an air flows A is used to blow away excessive coating material 6 from the surface of the top layer. FIG. 2b illustrates a beveled edge 22. FIG. 2c illustrates coating of a groove 23 which is located at a distance from the joint edge. In this embodiment, two air flows A, A can be used to blow away excessive coating material 6 from the surface and towards the groove.

(12) FIGS. 3a and 3b illustrate how a beveled edge 22, without the top layer, can be coated with liquid coating material, such as varnish or pigmented oil. In this embodiment, the floorboard 1 has an unmachined surface of a top layer 31 of, e.g., a laminate made of sheet material impregnated with thermosetting resins or varnished wood. The beveled edge is coated with coating material 6 which partly settles on the unmachined surface of the top layer 31. Excessive coating material is blown away by compressed air A which in this embodiment is blown parallel to the surface of the board and moves the excess material towards the beveled edge 22. FIG. 3b illustrates how the coating material 6 penetrates into the core 30 while at the same time the unmachined surface of the top layer 31 is free from coating material. Particularly good penetration can be achieved if the core consists of wood fiber-based materials, such as HDF, and if pigmented oils with a suitable viscosity are used, which is adapted to the absorbing capacity of the HDF material.

(13) FIGS. 5a and 5b illustrate an enlargement of the coating according to the embodiments in FIGS. 2a and 2c. The coating wheel 2 is arranged so as to transfer a liquid coating material 6 via surface tension from the outer edge wall 202 of the coating wheel 2 to the machined surface portion. The machined surface portions are coated with coating material 6 which partly settles on the unmachined surface of the top layer 31. The excessive coating material on the surface of the top layer is removed by an airflow. In the embodiment in FIG. 5a a groove in the sheet-shaped blank is coated. The width of the wheel portion W, which transfers coating material to the groove, is essentially equal to the width of the groove P or slightly smaller. In the embodiment in FIG. 5b an edge groove of the sheet-shaped blank is coated. The width of the wheel W, which transfers coating material to the edge groove, is preferably larger than the width of the edge groove P.

(14) If the edge of the wheel 2 has a suitable design and if the amount of coating material 6 is well adjusted while at the same time the amount, pressure and direction of the air are controlled in a convenient manner, coating of the machined edge can be performed with a better result than in using prior-art technique.

(15) FIGS. 4a-c illustrate how a beveled edge 22, without the top layer and parts of the mechanical joint system, in this case the tongue portion 32, can be coated, for instance, with a decorative material on the beveled edge 22 and with an impregnating moisture-repellent material on the tongue 32.

(16) In this embodiment coating is performed using two wheels 2, 2. The nozzle 3 has an outlet 24 directing the air substantially parallel to the unmachined surface of the top layer 31 towards the edge portion 22.

(17) In this embodiment the second wheel 2 operates substantially horizontally. The wheel can be coated with suitable liquid substances in different ways using, for example, a spray nozzle 25, with felt or suitable fiber materials containing the coating material and the like. Alternatively the wheel 2 can rotate in an associated vessel where the edges of the wheel establish a seal against the edges of the vessel. A plurality of wheels can be used. Various chemicals can be dried, hardened and the like after coating according to prior art, using ultrasound, UV light, heat etc.

(18) The edge of the wheels 2 can be designed in various ways and they can operate at optional angles from above and from below. All parts of a mechanical joint system that can be machined by means of large rotating tools can also be coated by means of wheels, preferably, but not necessarily, in combination with compressed air which facilitates positioning of the coating material.

(19) Wheels are preferably made of metal but they can also wholly or partly be made of plastic or rubber material. They can be heated and they can contain ducts directing the coating material to different contact surfaces between wheel and board. A plurality of different coating materials can be applied in different steps in succession. The wheels can also be used to shape, by pressure, parts of the joint edge by compression of fibers. Vacuum can be applied to the board in order to facilitate penetration. Liquid materials can be applied which after hardening become elastic and which then may constitute a joint seal that prevents moisture from penetrating through the joint system. In this case the edges do not have to be beveled.

(20) The chemical composition of the coating material is important for a good result. A suitable chemical for coating of wood fiber-based board materials such as HDF, MDF, particle board, plywood and the like is pigmented oil. Such a chemical quickly penetrates into wood fiber-based materials, prevents penetration of moisture into the machined surface portion while at the same time different pigments make it possible to provide decorative edge portions or grooves which may have the same shades of color as the surface of the top layer, or shades deviating therefrom. Suitable pigments are organic pigments which are used, inter alia, in the graphical industry for printing on paper. These pigments function well together with wood-based board materials. Vegetable alkyds can be used as binder for the pigments. Mineral oil can be used to reduce the viscosity so that the coating material quickly and easily can penetrate into the wood fiber-based core while at the same time it adheres to the wheel and does not leave the wheel at high peripheral speeds. A suitable composition measured in parts by weight is about 10-15% organic pigments, about 30-35% vegetable alkyds and 50-55% mineral oil. These parts by weight can also be 5 percentage units greater or smaller than the range stated. Of course, also other mixtures can be used within the scope of an important basic principle that the coating material should contain pigments, a binder and a viscosity-reducing agent. Another important basic principle is that the mixing ratios should be such that the greatest share is a viscosity-reducing agent while the lowest share is pigments.

(21) Further chemical substances can be added, such as other types of oils, hardeners and like agents. These agents can also be combined with additives that can improve the durability, such as alumina. It goes without saying that these additives may affect the above mixing ratios.

(22) Pigmented oil is highly convenient for use in floorboards with a surface layer of laminate. The oil does not penetrate into the laminate surface and easily slides off the laminate surface without leaving any visible traces when exposed to a suitable air flow which directs the oil towards the machined joint edge where it is easily and quickly absorbed by the HDF fibers.

(23) The chemical composition described above also constitutes an invention which can be used independently as a coating material, for instance together with the prior-art methods of, for instance, coating a surface in a joint edge preferably of a floorboard with a wood fiber-based core or surface layer.

(24) There may be a number of variants. The device can be used for coating of previously treated surfaces and for changing the surface properties in terms of appearance and function. Compressed air can be used to position and move liquid coating material also in the cases when coating is performed in some other manner than by means of wheels, for instance by means of coating tools that coat machined surfaces.