BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1
a-c illustrate a device and method according to known technology.
FIGS. 2-3 illustrate an embodiment of a building panel according to the invention.
FIG. 4 illustrates an embodiment of the device and method 15 according to the invention
FIG. 5 illustrates an embodiment of the press tool according to the invention, for compressing and forming of an edge portion of a building panel.
DESCRIPTION OF EMBODIMENTS OF THE INVENTION
As represented in FIGS. 2-5, an embodiment of the invention relates to a device and a method of producing a building panel with a compressed and curved edge and a building panel produced by the device and method.
A known device and method of producing a building panel with compressed and curved edges is shown with reference to FIGS. 1a-1c. In FIGS. 2 and 3 an embodiment of a building panel according to the invention is shown, produced by a device and a method according to the invention and provided with a well-known mechanical locking system.
FIGS. 1
a-c show in three steps the known method of forming the compressed edge. In FIG. 1a a building element is shown, which in a later step, FIG. 1b, is cut in to two buildings element (2, 2′) and provided with an edge groove 5 (6, 6′). The building element comprises a core (3), of a wood fibre based material, preferably HDF, MDF or particle board, a decorative surface (4) of a wood veneer, a laminate comprising paper sheets and a resin or a decorative printing and a balancing layer (5). A mechanical locking system, which 10 will be produced at a later stage, is indicated by a dotted line. In the second step heat is applied to the edges by a heat device (8). In the third step, illustrated in FIG. 1c, a press tool (9) compresses the core at the edge of the building panel and forms the curve shape (10, 10′).
In FIG. 2 an embodiment of the invention comprising a joint between two floor panels (1, 1′) with the compressed and curved edges (10, 10′) is shown. An example of a mechanical locking system is shown for vertical and horizontal locking. The horizontal locking comprises a locking strip (23), extending horizontally from a edge (24b, 24b) of a first floor panel (1) and provided with an upwardly projecting locking element (26), which cooperates with a locking groove (27) under and at the edge (24a, 25a) of a second floorboard (1′) The vertical locking comprises a tongue (21) at the edge (24b, 25b) of the first panel and a tongue groove (21) at the edge (24a, 25a) of the second floor panel (1′). Any type of locking may be used, e.g only vertical, only horizontal, a tongue lock (see WO02/055810) or in addition glue may be added.
FIG. 3 shows an embodiment of the floor panel provided with the mechanical locking system and curved edges (10, 10′) at a long edges and a decorative groove (30) at only one of the opposite short edges (25a, 25b).
An embodiment of the device and method according to the invention is illustrated in FIG. 4. The device comprising a conveyor (40) for moving a building panel (2) to a heat device (8). The heat device, e.g. infra-red heat element, is arranged for heating an edge of the building element. In a second step the conveyor moves the building panel to a press tool for compressing the edge of building panel. Preferably both opposite edges are heated and subsequently compressed at the same time by a rotating press tool. The device also comprises a lubricating device (41) arranged for applying a lubricate additive, preferably to the press tool or to the edge of the building panel.
A preferred lubricate additive is a synthetic teflon oil, but it is also possible to use a mineral and a organic oil with the same fluid and lubricating properties, which is possible to remove from the decorative surface. To reduce the friction further more, the surface of the press tool (9) may be grinded and/or tempered. As an example a material of tempered steel with a hardness of about 30-40 HRC may be used for the press tool, which may be tempered by nitro-carburizing to about 60-70 HRC and advantageously grinded to a roughness of about 0.2 Ra. Other method may be used for tempering for which a hardness may be achieved of about 30004000 Vickers. Generally, a harder and smoother press tool is desired, but leads to greater costs. For some material of the decorative layer and a compression in the lower range, it's possible to take out the lubrication and achieve the desired result by a grinded and tempered press tool.
Advantageously, the press tool (9) may be provided with a groove with a circular (50) or an elliptic shape (51, 52), which creates a corresponding circular or elliptic shape of the curved edge of the building panel. With an elliptic shape a visual effect is created that the curved edge looks deeper, if the radius of the ellipse in a direction (a), parallel to the decorative surface is larger than the radius of the ellipse in a direction (b), vertical to the decorative surface. The edge of the tool closest the middle of the building panel is preferably provided with a clearance angel (53).
The embodiment of the building panel shown in FIG. 2, produced by the aforementioned device and method according to the invention preferably comprises a core of a wood based material, e.g. HDF or MDF and a decorative layer of a laminate comprising paper sheets and a resin or a decorative printing, which combination is suitable for compression. Also other types of wood based cores, e.g particle board or plywood and other decorative surface may be used, e.g. veneer. Advantageously, the building panel is provided with a balancing layer (5).
Advantageously, the core at the curve shaped edge is compressed more than 0.5 mm and most preferably more than 0.7 mm. A preferred range of compression is between 0.5 mm to 1 mm. Also a smaller degree of compression is obviously possible, and even a larger, but a curved edge or bevel in this range looks the most natural. With the method and the device according to the invention a building panel with such a deep compression is possible to achieve without cracks in the decorative surface. The compressed edge may also comprise a straight part.
Patent Application
20080066425
