Panel, In Particular a Floor Panel
The invention relates to a panel, in particular a floor panel, with a core that
consists of a wood material or a wood material-plastic mixture, a top side and a
bottom side, which panel has on a first lateral edge a lower locking element,
which comprises a first arm that is arranged on the bottom side of the panel and
that projects over the first lateral edge, and a first hook element with an undercut
that is arranged on an outer end of the first arm. and which panel has on a second
lateral edge that is opposite to the first lateral edge an upper locking element with
a second arm that is arranged on the top side of the panel and that projects over
the second lateral edge, and a second hook element, which has at least one locking
nose, arranged on an outer end of the second arm. such that two identically
designed panels can be connected and locked to one another in the horizontal
direction and in the vertical direction after the locking nose of one panel is
snapped into the undercut of a second panel.
Such a panel is known, for example, from DE 199 29 896 A1. Two of the
panels described there are connected to one another by a joining motion that runs
perpendicular to the placement plane. In this case, both the lower locking element
and the upper locking element are widened continuously in an elastic manner until

the locking nose of one panel snaps into the undercut of the second panel. Two
thus connected panels are connected and locked to one another both in the
horizontal direction and in the vertical direction.
The strength of the lock. i.e.. the force that has to be applied to separate
once again two panels that are connected and locked to one another, is in this
case, i.a., determined in how far the locking nose of one panel can snap into the
undercut of the second panel. The further the locking nose engages in the
undercut, the stronger the lock in the panels is. To achieve as strong a locking as
possible, the locking elements are to be widened as far as possible in an elastic
manner. To this end. the material, of which the two locking elements consist, has
to have a relatively high elasticity.
DE 103 05 695 A I also discloses floor panels that can be connected to one
another by a joining motion that runs perpendicular to the placement plane. The
panels have an essentially mushroom-shaped locking strip on a lateral edge and an
essentially mushroom-shaped locking groove in cross-section on a lateral edge
opposite to this lateral edge. When two panels are joined together, the essentially
mushroom-shaped locking strip is now inserted into the locking groove. In this
case, the locking groove has to be widened elastically by the mushroom shape
until the mushroom-shaped locking strip snaps in.
Also, in this case, the locking groove has to be widened as far as possible
in an elastic manner as far as possible to achieve a strong locking of the two
panels relative to one another.

1
Also. DE 202 03 3111 U 1 discloses floor panels that can be locked to one
another by a vertical joining motion. Also, in the solution shown there, a locking
nose of one panel snaps into an undercut of the other panel. Also, in this case, the
locking element of one panel has to be widened to ensure locking.
As core material for the panels, in particular medium-density fiber plates
(MDF) or high-density fiber plates (HDF) are suitable. The latter have great
strength, so that they can readily withstand the stresses to which floor panels at
particular are exposed from walking. It is disadvantageous that these vehicles are
elastically deformable only to a slight extent. As a result, the locking elements
can be widened elastically only within a limited extent. Thus, the possible
strength of the locking of two panels is also limited by the selection of the core
material.
DE 10 2007 015 048 A1 discloses panels in which a spring element, which
can snap into a groove provided for this purpose on the opposite side of another
panel, is formed on at least one lateral edge. The spring element extends along
the lateral edge and is connected to the core of the panel only at its two ends. In
between, it is released by two grinding processes and can accordingly be deflected
horizontally. When the two panels are connected, the spring element is deflected
and snaps into the groove that is provided for this purpose in the second panel
when the two panels have reached the previously defined end position. As a
result, both panels are connected and locked to one another at least in the vertical
direction.

The strength of the locking is determined in this case by the thickness of
the spring element. In particular in the case of thin panels, the spring element
must also be designed very thin, so that in particular in these cases, it can result in
a locking that is not designed to be strong enough.
DE 10 2007 020 271 A1 discloses floor panels, on whose lateral edges
locking elements for vertical locking are provided. In this case, a locking
projection of a panel emerges through a window on the other panel and engages
the peripheral wall of this window. By the design of this window, a bending
beam clamped on two sides is formed, and said beam is deflected for locking and
snapped back again into the locking position.
It is disadvantageous that this bending beam, which extends along a literal
edge of a panel, is connected to the panel only at its two ends. In this respect, in
particular in floor panels that are laid on an uneven base, the heavy loads that
arise from walking can cause the connection between the bending beam and the
panel core to break. In this case, the two panels are no longer locked to one
another.
Moreover, because the locking element penetrates the window, it can
happen that the bending beam can have only about one-third of the panel
thickness count as thickness. In particular in the case of thin panels, the stability
of the locking is thus greatly reduced such that this solution can be applied only
for thick panels.

The object of the invention is therefore to improve the above-described
panels in such a way that even in the case of thin panels, a strong and secure
locking of two identical panels to one another is possible both in the vertical
direction and in the horizontal direction.
The invention achieves this object by a generic panel in which in the arm
of the lower connecting element, at least one integral slot is provided with a width
that is smaller than that of the second hook element.
This at least one slot releases a part of the first hook element relative to the
core in the horizontal direction. As a result, the first hook element can be
deflected more simply and further both primarily in the horizontal direction and
secondarily around an axis that is parallel to the lateral edge of the panel. As a
result, a further widening of the lower locking element is possible in such a way
that the locking nose of the second hook element can engage again in the undercut
of the lower locking element, by which the locking of both panels to one another
is strengthened.
Advantageously, the at least one slot runs parallel to the first lateral edge.
As a result, it is ensured that the production of such a panel is simple and quickly
possible. Because of the position and the length of the at least one slot, it is
possible to set very precisely how far the lower locking element can be widened
during the connecting and locking of the two panels with one another.
Advantageously, multiple slots are provided. As a result, it is ensured that
the arm of the lower locking element is not interrupted at specially stressed points.

for example in the middle of the lateral edge of the panel, and thus has a higher
stability.
The multiple slots are preferably arranged at various distances from the
first lateral edge. Advantageously, at least two slots run at least partially beside
one another. In this way. it is ensured thai the arm over the entire length of the
lateral edge is interrupted by at least one slot without weakening the stability of
the lower locking element too greatly.
At least one of the slots is advantageously arranged at one end of the first
lateral edge. As a result, the elasticity of the lower locking element is increased
primarily in the edge area.
Advantageously, at least one locking nose on the second hook element is
designed shorter than the second lateral edge.
The second hook element preferably has multiple locking noses that are
arranged beside one another. The positions of the at least one slot and the at least
one locking nose along the lateral edge preferably correspond to one another. In
this way, it is ensured that at the points at which a locking nose is located on the
second hook element, a slot in the arm is provided on the lower locking element.
As a result, the elasticity of the arm is increased at specifically these points, and a
deflection or widening of the lower locking element is facilitated. At the points at
which no locking nose is provided, in this case there is also no slot in the arm of
the lower locking element, so that the latter has full stability there. In particular.
when at least one of the slots is located on one end of the first lateral edge.

locking noses should also be provided at the end of the second lateral edge. The
latter can be even longer than the at least one slot at the end of the lateral edge
with use of the rotating deflection motion.
The return force of the lower locking element is mainly determined by the
position and the length of the at least one slot. The length of at least one locking
nose at the second hook element is also variable. It has a significant influence on
the motion that embodies the lower locking element. If the locking nose is shorter
than the corresponding slot, the first hook element is moved mainly horizontally.
If the length of the locking nose, however, is only slightly shorter than each of the
at least one corresponding slot, the first hook element is more strongly forced into
a rotating deflection motion.
Advantageously, the bottom side of the first arm runs at an angle a
relative to the horizontal upward. This reduction of the bottom side of the plate
provides for elevated elasticity of the lower locking element. As a result, it is
possible to widen the lower locking element still further without influencing the
stability of the arm.
The angle a advantageously is between 0 and approximately 15°.
When the first lateral edge above the first arm has an undercut, the free
length of the first arm is extended. As a result, the lower locking element can be
further widened when two identical panels are to be connected and locked to one
another.

The undercut can be designed as, for example, a groove, in particular a
groove that is rectangular in cross-section, in the first lateral edge above the first
arm.
The first lateral edge and the second lateral edge of a panel according to
the invention can in each case have a horizontal joining edge. By these joining
edges, a recess is formed on a lateral edge, and a corresponding projection is
formed on the opposite lateral edge of the panel. When two panels are laid and
joined together, in this case the projection is inserted into the recess. As a result.
the vertical positioning of the panels during the laying is decoupled from the
actual locking mechanism.
Using a drawing, embodiments of the invention are described in more
detail below. Here:
Figures 1 a to 1 c - show a cutaway of two panels according to a first
embodiment of this invention in various stages of
the locking process.
Figure 2 - shows a diagrammatic top view of a panel
according to a second embodiment of this invention.
Figure 3 - shows a section along the line 111 - 111 of figure 2.
Figure 4 - shows a cutaway of two panels according to a third
embodiment of this invention.
Figure 5 - shows a cutaway of two panels according to a
fourth embodiment of this invention.

Figure 6 - shows a cutaway of two panels according to a fifth
embodiment of this invention.
Figure 7 - shows another embodiment in a representation
according to Figure 4.
Figures 1 a to I c show various stages of the connecting process of two
identical panels. In this case, a first lateral edge 2 of a first panel 1 and a second
lateral edge 4 of a second panel 3 are shown. On a bottom side 6 of the first panel
I. a lower locking element 8 is arranged. The lower locking element 8 has a first
arm 10 that projects over the first lateral edge 2. on whose arm's one outer end a
first hook element 12 is arranged and which has a slot 26.
On a top side 14, the panel 3 has an upper locking element 16. The upper
locking element 16 comprises a second arm 18 that projects over the second
lateral edge 4, and on whose arm's other end a second hook element 20 is
arranged.
The first hook element 12 of the lower locking element 8 has an undercut
22. Corresponding to this, the second hook element 20 has a locking nose 2-1.
In the embodiment shown in Figure 2. two slots 26 have been introduced
into the first arm 10 of the lower locking element 8. In the arm 10. multiple .slots
26 can also be arranged parallel to one another, as is indicated in Figures 5 and 6.
Preferably, however, in each case only one integral slot 26 is provided.

In Figure 1 a. the two panels , and 3 are shown before the locking. - hey
are arranged relattve to one another in such a way that the locking can he done by
a vertical joining motion of the second panel 3 relative to the first panel 1
Figure 1 b shows the two panels 1.3 during the locking process. In
comparison to Figure I a, the second panel 3 is lowered relative to the first panel
1. In this case, the second hook element 20 provides for the lower locking
element 8 to be widened. In this case, the first hook element 12 can cmhod\ both
a horizontal movement toward the left as well as a rotation around an axis that is
perpendicular to the drawing plane. This is made possible by the slot 2b pr<>\ idci!
in the first arm 10 of the lower locking element 8.
In Figure I c. the two panels I. 3 are locked with one another. In this
case, the locking nose 24 of the second hook element 20 is snapped into the first
hook element 12 in the undercut 22. Here, the first hook element 12 again springs
back into its starting position.
The first hook element 12 extends over the entire length of the first lateral
edge 2. It can, for example, be produced simply by a stationary, tool aecordmg to
the principle of the stationary blade, whereby the motion of the workpiece is used
for machining. The lower locking element 8 itself is manufactured by. for
example, one or more permanent, rotating milling tools. The slots 26 can also be
made simply by a likewise rotating milling tool, which moves into and out of the
panel material by a sniveling movement during the transport of the panel. As an

In Figure 1a, the two panels 1 and 3 are shown before the locking. They
are arranged relative to one another in such a way that the locking can be done by
a vertical joining motion of the second panel 3 relative to the first panel 1.
Figure I b shows the two panels 1. 3 during the locking process. In
comparison to Figure 1 a, the second panel 3 is lowered relative to the first panel
1. In this case, the second hook element 20 provides for the lower locking
element 8 to be widened. In this case, the first hook element 12 can emhody both
a horizontal movement toward the left as well as a rotation around an axis that is
perpendicular to the drawing plane. This is made possible by the slot 26 pro\ ided
in the first arm 10 of the lower locking element 8.
In Figure 1 c, the two panels 1. 3 are locked with one another. In this
case, the locking nose 24 of the second hook element 20 is snapped into the first
hook element 12 in the undercut 22. Here, the tlrst hook element 12 again springs
back into its starting position.
The first hook element 12 extends over the entire length of the first lateral
edge 2. It can, for example, be produced simply by a stationary tool according to
the principle of the stationary blade, whereby the motion of the workpiece is used
for machining. The lower locking element 8 itself is manufactured by. for
example, one or more permanent, rotating milling tools. The slots 26 can also be
made simply by a likewise rotating milling tool, which moves into and out of the
panel material by a swiveling movement during the transport of the panel. As an

alternative, other methods such as lasers or punches can also be used. The
production can be carried out in a continuous or clocked process.
In the embodiment shown, the locking nose 24 of the second hook element
20 does not extend over the entire length of the second lateral edge 4. Its length
corresponds to the position of the slot 26 in the first arm 10. It is thus ensured
that the elasticity of the lower locking element 8 is increased precisely at the
location where a deflection of the first hook element 12 is necessary for locking
the two panels 1,3. At the locations at which no locking nose 24 is provided, the
lower locking element 8 has full stability. The locking nose 24 is formed by for
example, a stationary tool. The number of locking noses 24 corresponds to the
number of slots 26 (cf. Figure 2).
For locking and connecting the two panels, the second hook element 20 is
guided behind the first hook element 12 on the first panel 1 by a rocking of the
second panel 3. Here, the locking nose 24 deflects the first hook element I 2 untit
it has passed the latter. This is enabled or simplified by the slot 26 provided in the
first arm 10. Then, the first hook element 12 is moved back into its starting
position, by which the two panels 1. 3 are both locked in horizontal and in vertical
direction. If multiple locking noses 24 are provided, a locking nose 24 for locking
nose 24 is locked when the second panel 3 is rocked so that a connection is
produced depending on the type of slide fastener.
Figure 2 shows a diagrammatic top view of a first panel 1. A lower
locking element 8 is molded onto the first lateral edge 2. This lower locking

element 8 again has a first arm 10 and a first hook element 12. In the embodiment
that is shown, two slots 26 that are arranged on the respective ends of the first
lateral edge 2 are provided in the first arm 10. As a result, the elasticity of the
lower locking element 8 is increased especially in the edge area. Preferably, two
locking noses that also are arranged in the outer edge areas of the lateral edge and
that are matched in this respect to the opposite lateral edge, not shown, are
provided.
Figure 3 shows a section along the line III-III according to Figure 2.
The lower locking element 8 is arranged on the bottom side 6 of the first
panel 1. A slot 26 is provided in the first arm 10 of the lower locking element 8.
In this case, the bottom side 28 of the first arm 10 runs at an angle a
relative to the horizontal upward. As a result, the elasticity of the lower locking
element 8 is increased again, without the stability of the first arm 10 being further
impaired. In this way, the first hook element 12 can be further defiected when
two identical panels are joined together. The angle a is preferably between 0 and
approximately 15°.
Figure 4 shows a cutaway of two panels I. 3 before they are joined
together. As in Figure 3, the lower locking element 8, whose first arm 10 has a
bottom side 28 that runs upward relative to the horizontal II at an angle a that is
not indicated, is arranged on the bottom side 6 of the first panel I. When the
panels 1, 3 are joined together, the first hook element 12 is again defiected until
the locking nose 24 on the second hook element 20 engages in the undercut 22 on

the first hook element 12 that is provided for this purpose. The panel 1 has a
horizontal joining edge 30 on its first lateral edge 2. A horizontal joining edge 30
is also provided on the second lateral edge 4 of the second panel 3. In this case.
the two horizontal joining edges 30 are designed in such a way that they rest on
one another in the connected and locked state of panels I. 3. The projection
formed by the horizontal joining edge 30 and located on the panel 3 coming from
above is inserted here into the recess that is formed by the horizontal joining edge
30 on the first panel I. As a result, it is ensured that the positioning of the panels
1, 3 is decoupled from the actual locking mechanism.
Figure 5 shows a cutaway of two panels I. 3 according to a fourth
embodiment of this invention. As in the above-described embodiments, the lower
locking element 8 is arranged on the bottom side 6 of the first panel 1. Two slots
26 are arranged in the first arm 10. whose bottom side 28 again runs upward in an
angle a relative to the horizontal H. For locking, the second hook element 20 of
the upper locking element 16. which is arranged on the top side 14 of the second
panel 3, engages in the first hook element 12. On its first lateral edge 2. the first
panel I has a rectangular groove 32. through which the freedom of motion of the
lower locking element 8 and thus the first hook element 12 is further increased.
In this way, it is achieved that when the two panels 1. 3 are locked, the first hook
element 12 can be further deflected without the stability of the first arm 10 being
impaired. In Figure 6, the same effect is caused by an undercut 34 that is
provided in the first lateral edge 2 of the first panel I. In this way. the free length

of the first arm 10 is extended in such a way that when the two panels 1. 3 are
locked, the first hook element 12 can be further deflected without impairing the
stability of the first arm 10.
Also, in Figure 6, the bottom side 28 of the first arm 10 runs upward at an
angle a relative to the horizontal H.
In the embodiment that is shown in Figure 7. the contact surfaces 35. 36 of
the first and second hook elements 12. 20 run at an angle |j that is inclined relative
to the horizontal. In such a configuration, the locking process proceeds with little
effort.

Reference Symbol List
1 First panel
2 First lateral edge
3 Second panel
4 Second lateral edge
6 Bottom side
8 Lower locking element
10 First arm
12 First hook element
14 Topside
16 Upper locking element
18 Second arm
20 Second hook element
22 Undercut
24 Locking nose
26 Slot
28 Bottom side
30 Horizontal joining edge
32 Rectangular groove
34 Undercut
35 Contact surface
36 Contact surface
a Angle
P Angle
H Horizontal

We Claim:
1. Panel, in particular a floor panel, with a core that consists of a wood
material or a wood material-plastic mixture, a top side (14) and a bottom side (6),
which panel has on a first lateral edge (2) a lower locking element (8), which
comprises a first arm (10) that is arranged on the bottom side (6) of the panel and
that projects over the first lateral edge (2), and a first hook element (12) with an
undercut (22) that is arranged on an outer end of the first arm (10), and which
panel has on a second lateral edge (4) that is opposite to the first lateral edge (2)
an upper locking element (16) with a second arm (18) that is arranged on the top
side (14) of the. panel and that projects over the second lateral edge (4), and a
second hook element (20), which has at least one locking nose (24), arranged on
an outer end of the second arm (18), such that two identically designed panels can
be connected and locked to one another in the horizontal direction and in the
vertical direction after the locking nose (24) of one panel is snapped into the
undercut (22) of a second panel, characterized in that in the first arm (10) of the
lower locking element (8), at least one integral slot (26) is provided with a width
that is smaller than that of the second hook element (20).
2. Panel according to Claim 1, wherein the at least one slot (26) runs
parallel to the first lateral edge (2).

3. Panel according to Claim 1 or 2, wherein multiple slots (26) are
provided.
4. Panel according to Claim 3, wherein the slots (26) are arranged at
varying distances from the first lateral edge (2).
5. Panel according to Claim 4, wherein at least two slots (26) run at least
partially beside one another.
6. Panel according to one or more of the foregoing claims, wherein at
least one slot (26) is arranged at one end of the first lateral edge (2).
7. Panel according to one or more of the foregoing claims, wherein the at
least one locking nose (24) is shorter than the second lateral edge (4).
8. Panel according to one or more of the foregoing claims, wherein the
second hook element (20) has multiple locking noses (24).
9. Panel according to one or more of the foregoing claims, wherein the
positions of at least one slot (26) and at least one locking nose (24) along the
lateral edges (2,4) correspond to one another.

10. Panel according to one or more of the foregoing claims, wherein the
bottom side (28) of the first arm (10) runs at an angle a relative to the horizontal
upward.
11. Panel according to Claim 10, wherein the angle a is between 0 and
approximately 15°.
12. Panel according to one or more of the foregoing claims, wherein the
first lateral edge (2) has an undercut (34) above the first arm (10).
13. Panel according to Claim 12, wherein the undercut (34) in the first
lateral edge (2) is designed as a groove (32) above the first arm (10).
14. Panel according to Claim 13, wherein the groove (32) is a groove (32)
that is rectangular in cross-section.
15. Panel according to one or more of the foregoing claims, wherein the
first lateral edge (2) and the second lateral edge (4) in each case have a horizontal
joining edge (30).

Panel, in particular a floor panel, with a core that consists of a wood
material or a wood material-plastic mixture, a top side (14) and a bottom side (6),
which panel has on a first lateral edge (2) a lower locking element (8), which
comprises a first arm (10) that is arranged on the bottom side (6) of the panel and
that projects over the first lateral edge (2), and a first hook element (12) with an
undercut (22) that is arranged on an outer end of the first arm (10), and which
panel has on a second lateral edge (4) that is opposite to the first lateral edge (2)
an upper locking element (16) with a second arm (18) that is arranged on the top
side (14) of the panel and that projects over the second lateral edge (4), and a
second hook element (20), which has at least one locking nose (24), arranged on
an outer end of the second arm (18), such that two identically designed panels can
be connected and locked to one another in the horizontal direction and in the
vertical direction after the locking nose (24) of one panel is snapped into the
undercut (22) of a second panel, characterized in that in the first arm (10) of the
lower locking element (8), at least one integral slot (26) is provided with a width
that is smaller than that of the second hook element (20).