Note: Descriptions are shown in the official language in which they were submitted.
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DEVICE AND METHOD FOR COMPRESSING AN EDGE OF A BUILDING PANEL
AND A BUILDING PANEL WITH COMPRESSED EDGES
Area of Invention
The present invention generally relates to a device
and a method of compressing an edge of a building panels,
especially floorboards, which have a wood fibre based core and
a decorative layer, to provide curved edge portions. More
particularly, the present invention relates to interlocked
building panels with compressed edge portions located below the
panel surface. The invention relates to panels with such edge
portions and to a method and device to produce such panels.
Background of the Invention
In particular, yet not restrictive manner, the
invention concerns a device and a method of producing a
laminate floor panel with a curve shaped and compressed edge.
However, the invention is as well applicable to building panels
in general. More particularly invention relates to the type of
floor panels with a wood fibre based core, e.g. HDF, MDF,
particleboard, plywood, a decorative layer and a mechanically
locking system for horizontal and/or vertical locking produced
by the method and device.
A device, method and floor panel of this type is
presented in W02006/088417, which discloses a device and method
to compress the edges of a laminate floor panel to provide a
laminate floor panel with curve shaped edges looking like a
solid wood floor panel with bevelled edges.
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Summary of the Invention
The invention aims at an improved device and a method
of producing building panels, especially floorboards, with a
curved edge portion made in one piece with the decorative
layer, which could be produced with high speed. The invention
also makes it possible to produce deeper curved edge portion
compared to the known technology.
An additional purpose of this invention is to provide
building panels comprising a decorative layer and a curved edge
portion, produced with the device and the method.
A device, method and floor panel of this type is
known from W02006/088417, which discloses a device and method
to compress the edges of a laminate floor panel, to provide a
laminate floor panel with a curve shaped edge. The known device
comprises a heat device and a press tool for heating and
compressing the edge part of the panel.
The known method comprises the steps of:
= Applying the decorative layer on the core to form a
building element.
= Cutting the building element into building panels.
= Applying heat and pressure on the surface of an
edge portion of the building panel such that the core under the
decorative layer is compressed and the surface layer is
permanently bended towards the rear side of the core.
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The drawback of this known device and method is that
cracks arise in the decorative layer if the pressure is applied
too fast or if the degree of compression is too high.
The first object of some embodiments of the invention
is to provide an improved device. The device according to some
embodiments of the invention comprises a heat device, a press
tool and a lubricating device for lubrication of the press
tool, which make it possible to produce building panels with
high speed.
Advantageously, the tool is arranged rotatable and is
configured to rotate when applying the pressure on the edge of
the building panel.
Preferably, the lubricating device is arranged to
apply the lubricate additive at the press tool. The lubricate
additive may be of any type of grease or oil easy to wipe off
from the present type of decorative surface. A preferred
example is synthetic teflon oil, but it is also possible to use
a mineral and an organic oil with the same fluid and
lubricating properties, which is possible to remove from the
decorative surface.
Preferably, the heating device comprises an IR (infra
red) heat element. In a preferred embodiment also the tool is
heated.
Preferably, the shape of the tool comprises an
elliptic groove, with a larger radius in a plane parallel to
decorative surface and consequently the smaller in a plane
vertical to the decorative surface. This results in a bevel,
which looks deeper/bigger.
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Preferably, the surface of the tool is grinded. This
results in lower friction between the decorative surface and
the press tool, resulting in fewer cracks in the decorative
surface.
The second object of some embodiments of the
invention is to provide an improved method to produce a
building panel with a compressed edge. The method comprising:
= Heating an edge of the building panel.
= Lubricating the edge of the building panel or an
press tool.
= Compressing the edge of the building panel with the
press tool.
Advantageously, the method also comprises heating of
the tool.
Preferably, the method comprises moving the building
panel relative the tool via a conveyor. The speed of the
conveyor is preferably more than 50m/m and most preferably
100m/m or higher.
The third object of some embodiments of the invention
is to provide an improved building panel with a curved edge,
produced by the device and method aforementioned. The building
panel preferably has an elliptic outer edge. 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. With the method
and the device according to the invention it is possible to
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produce a building panel with such a deep compression without
cracks in the decorative surface.
Building panels with a curved edge portion are
described in W02006/088417. Two main types of curved edges are
5 shown in W02006/088417, the old type, which involves cutting of
a part of the core at the edge of the building panel or
pressing the whole building panel, forming the curve shape, and
a new type involving compression of the edges. The two types
may look the same but the new type has a compressed core, with
higher density, at the edge. W02006/088417 also disclose a
measuring method for distinguishing the two types. A building
board according to the invention is possible to distinguish
from the old types with the measuring method described in
W02006/088417 and from the new type that there are fewer or no
cracks in the decorative surface at the curved edge. The
difference is increased with larger radius and degree of
compression.
Some embodiments of the invention relate to a device
for producing a building panel with a compressed and curved
edge portion, whereby the device comprises a heating device
arranged to heat the edge of the building panel and a press
tool arranged to compress the core of the building panel at the
edge of it wherein the device comprises a lubricating device,
which supplies a lubricate additive to the compressing zone.
Some embodiments of the invention relate to a method
of producing a building panel with a curved edge portion,
wherein the method comprising: heating an edge of the building
panel, lubricating the edge of the building panel or an press
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tool and compressing the edge of the building panel with the
press tool.
All references to "a/an/the [element, device,
component, means, step, etc]" are to be interpreted openly as
referring to at least one instance of said element, device,
component, means, step, etc., unless explicitly stated
otherwise.
Brief Description of the Drawings
Figs la-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 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 figures 2-5, 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 prior art device and method of producing a building
panel with compressed and curved edges is shown with reference
to figs la-lc. In figure 2 and 3 an embodiment of a building
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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.
Figures la-c shows in three steps the prior art
method of forming the compressed edge. In figure la a building
element is shown, which in a later step, fig lb, is cut into
two buildings element (2, 2') and provided with an edge groove
(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 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 lc, a press tool (9)
compresses the core at the edge of the building panel and forms
the curve shape (10, 10').
In figure 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 an edge (24b, 25b) 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 groove (21) at the edge
(24b, 25b) of the first panel and a tongue (22) at the edge
(24a, 25a) of the second floor panel (1'). Any type of locking
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may be used, e.g. only vertical, only horizontal, a tongue lock
(see W002/055810) or in addition glue may be added.
Figure 3 shows an embodiment of the floor panel
provided with the mechanical locking system and curved edges
(10, 10') at the 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 figure 4. The device comprising
a conveyor (40) for moving a building panel (1) 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 furthermore, 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 3000-4000 Vickers. Generally,
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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 angle
(53).
The embodiment of the building panel shown in
figure 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
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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
5 compression is possible to achieve without cracks in the
decorative surface. The compressed edge may also comprise a
straight part.
