Leak-proof and shatter-resistant panel including a locking element and method for producing such a panel

Abstract

The present invention relates to a panel, comprising: a panel body extending in a longitudinal direction and a transverse direction; a fixing groove extending in the transverse direction in the short side of the end of the panel body; and a locking element inserted into the fixing groove and becoming immovable, wherein, for the extension part b0 of the fixing groove in the transverse direction, with respect to the nominal width B of the panel body between a first edge extending in the longitudinal direction and a second edge of the panel body extending in the longitudinal direction, the following applies: 0.50 ≤ b0 / B ≤ 0.97, in particular 0.75 ≤ b0 / B ≤ 0.95, preferably 0.85 ≤ b0 / B ≤ 0.93, and particularly preferably b0 / B = 0.90 ± 0.02. By means of the fixing groove extending only on most of the short side and by means of the locking element immovably received in the fixing groove, a panel that is not easily broken and leak-proof can have good and material-friendly locking.

Description

Technical Field

[0001] The present invention relates to a panel having high fracture strength and high impermeability, preventing liquid from reaching the lower surface of the panel, and the surfaces of a room can be covered by means of panels interlocking with each other, in particular interlocking with each other by means of fixed locking elements, especially for improving the visual appearance of a room and / or covering the surfaces of a room with a material layer more suitable for the intended function; and a method for manufacturing such a panel. Background Art

[0002] It is known from WO2007 / 079845A1 that fixing grooves are provided on the short sides of the entire lateral extension of the panel, and locking elements designed as latching clips can be inserted into the fixing grooves and become immovable.

[0003] It is known from WO2010 / 087752A1 that partially circular grooves are seen in a partial area of the short sides of the panel, and projections of the locking elements provided outside the grooves can be displaced in the lateral direction into the grooves, where the projections can slide along the circular edges of the partially circular grooves, thereby pressing the locking elements having longitudinal direction moving parts into the opposite grooves of another panel.

[0004] In order to prevent liquid penetration, it is necessary to continuously improve the fracture strength and impermeability of the panel. Summary of the Invention

[0005] The object of the present invention is to provide measures capable of realizing an anti-seepage panel.

[0006] This object is achieved by the panel and method of the present invention. Preferred embodiments of the present invention are provided in the dependent claims and the following description, and each of these embodiments can form an aspect of the present invention alone or in any combination.

[0007] An embodiment of the present invention relates to a panel for covering the surface of a room, comprising: a panel element extending in the longitudinal direction and the lateral direction, for transferring the service load introduced at the upper surface of the panel element to the lower side of the panel element facing the room surface, wherein the upper side is spaced apart from the lower side in the thickness direction; and a fixing groove extending in the lateral direction in the short side of the end face of the panel element; and a locking element inserted into the fixing groove, in particular inserted in a substantially immovable manner; wherein, the extension b0 of the fixing groove in the lateral direction, relative to the nominal width B of the panel element between the first edge of the panel element extending in the longitudinal direction and the second edge of the panel element extending in the longitudinal direction, 0.50≤b0 / B≤0.97, in particular 0.75≤b0 / B≤0.95, preferably 0.85≤b0 / B≤0.93, particularly preferably b0 / B = 0.90±0.02.

[0008] The panel may include panel elements based on a cuboid as the basic shape, where the longitudinally extending portion of the panel element is generally significantly greater than its laterally extending portion, while the thickness of the panel element in the thickness direction is generally less than its laterally extending portion. At one long side extending in the longitudinal direction, the panel element may include, in particular, a plug projection that extends continuously in the longitudinal direction and protrudes in the lateral direction, while on the other side, it may include a plug groove formed in the panel element in the lateral direction, such that panels of substantially the same design can be connected to each other at adjacent long sides by a tongue-and-groove connection configured in the form of a plug. In particular, a locking hook may protrude from the short laterally extending side of the panel element in the longitudinal direction, while a tongue body may protrude from the other short side of the panel element, which defines a receiving groove, such that panels of substantially the same configuration can also be locked together at their short sides by a tongue-and-groove connection. In addition to or as an alternative to the tongue-and-groove connection formed by means of the receiving groove of the locking hook and the tongue body, a locking element may be inserted into a fixing groove provided at the short side of one panel, in particular immovably inserted, and the fixing groove may engage with a locking groove provided at the short side facing the other locking element, in particular for panels of substantially the same design. For this purpose, a locking element designed, in particular, in the form of a locking clip may include a locking connecting plate having a locking lug, which can be elastically pushed aside when the panel moves past during the assembly process so as to elastically snap at least partially into the locking groove at the designated end position of the panels to be interlocked, in particular together with the locking lug, thereby fixing the interlocked panels and preventing accidental release. During the assembly process, one panel may be placed flat on a subsurface defining the use plane, such as the floor, side wall, or ceiling of a room. Another panel may be selectively tilted slightly, for example, at an angle of approximately 30°, placed on the installed panel, laterally extending next to the panel at the long side, and then rotated onto the subsurface, whereby at least one interlock of the panels facing each other at the short sides can be established. During the interlock, on the one hand, the locking hook can be locked into the fixing groove of another panel, and on the other hand, the locking element inserted into the fixing groove can be locked into the locking groove of another panel substantially simultaneously. The extending portion of the locking groove in the lateral direction particularly corresponds to the extending portion of the fixing groove in the lateral direction. In particular, the extending portion c0 of the locking groove in the lateral direction relative to the nominal width B of the panel element is 0.50 ≤ c0 / B ≤ 0.97, in particular 0.75 ≤ c0 / B ≤ 0.95, preferably 0.85 ≤ c0 / B ≤ 0.93, and particularly preferably c0 / B = 0.90 ± 0.02. Preferably, the locking groove and the fixing groove have the same configuration and / or are produced by the same manufacturing process, which particularly simplifies the simultaneous and / or identical production of the locking groove and the fixing groove. The fixing groove for accommodating the pre-assembled locking element may be provided at one short side of the panel, while the locking groove is provided at the other short side of the panel.

[0009] Since the fixing groove and / or the locking groove are not provided over the entire lateral extent of the panel element, but only in a partial region of the lateral extent, it is possible to avoid weakening the panel element in the transition region between the short side and the long side at the corner of the panel element. In this case, use is made of the knowledge that, in the case where the fixing groove is continuous in the lateral direction, the fixing groove and the plug groove terminate at the corner of the panel element, with the result that there is a particularly large lack of material in the transition region between the short side and the long side and the strength of the panel may thus be impaired. Furthermore, it is possible to avoid the occurrence of water outlets at the longitudinal edges of the panel, through which water could seep downwards. Instead, the bottom of the plug groove is also closed at the short side, thus providing an effective barrier against water seepage. However, since the fixing groove extending in the lateral direction at the short side is spaced apart from the plug groove extending in the longitudinal direction at the long side, sufficient material of the panel element is retained between the fixing groove and the plug groove, thus avoiding a significant impairment of the strength of the panel element in the transition region between the short side and the long side compared to the strength of the remaining plug groove and / or the remaining fixing groove. This at least reduces the risk of damage to the panel when it is heavily stressed at the corner, especially when it is transiently heavily stressed, such as when an office chair drives over the corner or a table leg is supported at the corner. If the locking element is inserted into the fixing groove not movably but immovably, it is possible to minimize the air gap between the locking element and at least a part of the surface of the fixing groove facing the locking element, especially by eliminating the air gap by means of a press fit. Thus, breakage of the material defining the fixing groove can be avoided. Instead, the locking element can fill a large part of the volume of the fixing groove, especially more than 50%, preferably more than 75%, further preferably more than 85%, particularly preferably more than 95%, whereby the load acting on the panel element material defining the fixing groove can be transmitted via the locking element. Thus, the breaking strength of the panel is increased, especially in the corner region of the panel.

[0010] At the same time, the hydraulic connection between the fixing groove and the plug groove can be avoided or at least reduced. Thus, compared with the flow cross-section along the fixing groove in the transverse direction and / or along the plug groove in the longitudinal direction, a larger collecting volume at the T-joint of the three panels can be avoided, otherwise two plug grooves and one fixing groove would be open. The capillary force acting on the penetrated liquid can be avoided from decreasing, so that the penetrated liquid can also evaporate more easily at the T-joint at a later time and / or escape again from the joint between the panels. The accumulation of liquid in the collecting volume, from which the liquid can reach under the panel element, especially due to the increase in hydrostatic pressure over time, the liquid remains in the collecting volume and thus promotes the formation of mold, which can be at least mitigated or even avoided. Therefore, the risk of liquid reaching under the panel through the joint between the panels is at least reduced, so that the impermeability to prevent the liquid from reaching under the panel is improved.

[0011] The impermeability of the panel can be measured by filling a bottom- and top-open container with a liquid, especially water, in a predetermined specific volume so that the liquid in the container reaches a defined filling level and thus generates a defined hydrostatic pressure. The container filled with the liquid is centered on the T-joint intersection area formed between three interlocking panels on the three panels. After a predetermined time, the liquid level of the liquid remaining in the container is a measure of the impermeability to prevent the liquid from penetrating into the joint formed between the interlocking panels.

[0012] Since the fixing groove does not extend over the entire transverse extension of the panel element, the locking element can also have an extension in the transverse direction that is smaller than the entire transverse extension of the panel element. Here, the knowledge is utilized that the locking element in the design, in the form of a locking clip, provides a sufficiently good locking even with a smaller transverse extension due to the form-fitting clip connection, such that there is no need to provide locking over the entire transverse extension of the panel element at all. At the same time, the transverse extension of the locking element is still large enough so that the forces acting on the locking element during locking can be distributed over a larger area and the local mechanical load on the locking element can be kept at a low level. Through the ratio of the extension b0 of the selected fixing groove in the transverse direction to the nominal width B of the panel element, improved fracture strength and improved impermeability are achieved in the corner region of the panel element, while ensuring good locking of the locking element under low component loads. Through the fixing groove that extends only over a large part of the short side and the locking element received in the fixing groove, an anti-fracture and anti-seepage panel with good locking in terms of material can be achieved.

[0013] In particular, the locking element is inserted into the fixing groove in such a way that the locking element is prevented from moving in the transverse direction in a frictional and / or form-fitting manner. In particular, it can be provided that the locking element strikes the respective end of the fixing groove and cannot move further. Preferably, a clearance fit is formed between the fixing groove and the locking element in the transverse direction. Particularly preferably, an interference fit is formed between the fixing groove and the locking element in the thickness direction, whereby hardening of the material of the panel element forming the fixing groove can be achieved. Suitable locking elements are described, for example, in WO2007 / 079845A2, the content of which is incorporated herein by reference as part of the present invention.

[0014] In particular, a first strengthening region having an extension t1 in the transverse direction is formed between the first ends of the fixing groove, the first ends of the fixing groove facing the first edge in the transverse direction; wherein, a second strengthening region having an extension t2 in the transverse direction is formed between the second ends of the fixing groove, the second ends of the fixing groove facing the second edge in the transverse direction; wherein, for the first strengthening region, 0.005 ≤ t1 / B ≤ 0.090, in particular 0.015 ≤ t1 / B ≤ 0.050, preferably 0.020 ≤ t1 / B ≤ 0.030, particularly preferably t1 / B = 0.025 ± 0.002, and / or for the second strengthening region, 0.005 ≤ t2 / B ≤ 0.090, in particular 0.015 < t2 / B < 0.050, preferably 0.020 ≤ t2 / B ≤ 0.030, particularly preferably t2 / B = 0.025 ± 0.002, provided that t1 + b0 + t2 = B. The corresponding strengthening regions adjoin the relevant edges of the panel element and extend in the transverse direction along the short sides to the relevant ends of the fixing groove. Thus, the strengthening regions are designed without fixing grooves. Instead of the fixing grooves that would originally be provided in the strengthening regions, the volume of the originally existing fixing grooves is filled with the material of the panel element. This accumulation of material in the strengthening regions results in an increase in the stability and fracture strength of the corner regions of the panel element. At the same time, the corresponding strengthening regions are short enough such that a sufficiently large portion of the transverse extension of the short sides remains for the fixing grooves and the locking elements inserted into the fixing grooves.

[0015] Preferably, the panel element includes a plug groove extending into the panel element at the first edge and a plug projection protruding from the panel element at the second edge, where t1 < t2, in particular 0.75 ≤ t1 / t2 ≤ 0.99, preferably 0.80 ≤ t1 / t2 ≤ 0.95, and particularly preferably 0.85 ≤ t1 / t2 ≤ 0.90. It can be considered here that due to the plug projection, the panel element is designed to be more stable and stronger at the second edge than at the first edge where the plug groove is provided. Therefore, it is possible to allow the second strengthening region in the transverse direction to be correspondingly shorter than the first strengthening region. In the joint region between two panels with their long sides adjacent to each other and having basically the same structure, a joint strengthening region t1 + t2 is obtained at the two long sides of the corresponding panels, where the first strengthening region is provided by one panel and the second strengthening region is provided by the other panel. As a result, while good fracture safety can be achieved in the region of the plug groove, good fracture safety can also be achieved at the joint of the plugs formed at the long sides. The plug groove is provided inside the panel element between the first edge and the second edge of the panel element. The plug projection protrudes from the remaining part of the panel element. The plug projection can be integrally formed with the panel element and is thus arranged outside the nominal width B of the panel element measured from the first edge to the second edge, such that the extended portion of the plug projection does not affect the nominal width B of the panel element.

[0016] Particularly preferably, the extended portion b1 of the locking element in the transverse direction is 0.40 ≤ b1 / B ≤ 0.95 relative to the nominal width B of the panel element, in particular 0.50 ≤ b1 / B ≥ 0.90, preferably 0.60 ≤ b1 / B ≤ 0.80, and particularly preferably b1 / B = 0.70 ± 0.05. The extended portion of the locking element in the transverse direction of the panel element can in particular substantially correspond to the extended portion of the fixing groove in the transverse direction. However, it is also possible to select the extended portion of the locking element in the transverse direction to be slightly or significantly smaller than the extended portion of the fixing groove. For example, the size of the extended portion of the locking element can be determined substantially only with respect to the locking function and the expected forces to be borne in this regard, whereby it is very likely that the extended portion of the locking element can be selected to be smaller than the extended portion of the fixing groove. In this case, in principle, the extended portion of the fixing groove in the transverse direction can also be adapted to the smaller extended portion required by the locking element. However, if the extended portion of the fixing groove in the transverse direction is selected to be significantly larger than the extended portion of the locking element, there can be alternative manufacturing options for the fixing groove. Instead of machining the fixing groove with a pin-shaped milling cutter advancing in the transverse direction, the diameter of which particularly corresponds to the extended portion of the fixing groove in the thickness direction, the fixing groove can be cut into the panel element by a circular saw or a peripheral milling cutter, since a circular feed area can be allowed at the end of the fixing groove. Therefore, the production of the fixing groove can be faster and cheaper.

[0017] In particular, the frictional fit of the locking element in the fixing groove is provided only by the clamping force directed in the thickness direction. The locking element can be clamped between the upper surface of the fixing groove and the lower surface of the fixing groove in the thickness direction. Preferably, the hooks and / or spindles protruding from the locking element are driven into the material of the locking element in a form-fitting manner, and this material defines the fixing groove. There is just no clamping in the lateral direction. Therefore, unnecessary shear forces acting on the locking element can be avoided. In addition, when the locking element is inserted into the fixing groove, the locking element may be elastically bent slightly in the lateral direction, which is beneficial for pressing the locking element into the fixing groove and / or driving the hooks and / or spindles into the material of the fixing groove.

[0018] Preferably, the locking element includes a latching connecting plate that can be elastically bent at least partially in the direction of the fixing groove. Therefore, the locking element can be configured as a latching clip. If, when two panels are latched, one panel moves past the other panel, especially during a rotational movement, the panel can elastically bend the latching connecting plate towards the fixing groove of the locking element and / or at least partially move it into the fixing groove of the locking element, so that the panel can move past the locking element. At a predetermined end position, the locking element, especially the latching lug of the latching connecting plate, can be elastically snapped into the latching groove of the moving panel to achieve a latched connection. The latching connecting plate of the panel can be at least partially engaged in the latching groove of the other panel, thus forming a tongue-and-groove connection.

[0019] Particularly preferably, the fixing groove includes a receiving space adjacent to one end face of the short side and a fastening space. The receiving space is for receiving a part of the locking element, especially for temporarily receiving the elastically bendable latching connecting plate of the locking element. The fastening space is adjacent to the side of the receiving space away from the end face. The fastening space is for fastening the fastening protrusion of the locking element in a frictional or form-fitting manner, wherein the extension of the fastening space in the thickness direction is smaller than the extension of the receiving space in the thickness direction. The fastening of the locking element in the fixing groove, especially in an immovable manner, can be achieved to a large extent or completely by the engagement of the fastening protrusion of the locking element into the fastening space. At the same time, the locking element can provide sufficient free space in the volume of the receiving space of the fixing groove. When the panel to be latched moves past, the elastically flexible latching connecting plate of the locking element or other components that bring about the latching effect can be engaged into the free space. The relative movement of the panels for latching the two panels will not be blocked by the locking element.

[0020] In particular, the locking element bears against two surfaces of the receiving space that face in the thickness direction, in particular with a clamping force. In particular, the locking element includes a receiving pocket that extends into the receiving space and is used to temporarily receive the elastically flexible latching connection plate that is integrally connected to the locking element. This makes the fastening of the locking element in the fixing groove immovable and / or, in particular, fastened in a load-transmitting manner. It is even possible to allow the locking element to elastically bend in the thickness direction within the volume of the receiving space. Therefore, the locking element can be manufactured at a lower cost. Since the locking element bears against the surfaces that face in the thickness direction, at least some frictional engagement is provided, which can make it more difficult for the locking element to slip out of the fixing groove. A free volume for forming the receiving pocket can be provided between the material regions of the locking element that bear against the surfaces. This allows the elastically bendable latching connection plate to pivot sufficiently into the receiving pocket when the panel to be locked passes by, and allows the locking element to engage well frictionally within the fixing groove.

[0021] Preferably, at the short side where the fixing groove is formed, the panel element includes a locking hook that projects in the longitudinal direction from the short side of the panel element and is used to lock into the receiving groove of another panel. This enables the locking of one panel to another panel to be achieved both by engaging the locking element with the locking groove of the other panel and by engaging the locking hook with the fixing groove of the other panel. Suitable locking hooks and suitable tongues including fixing grooves are described in WO2006 / 133690A1, the content of which is incorporated herein by reference as part of the present invention.

[0022] Particularly preferably, the fixing groove has a cross-sectional area in a cutting plane spanned by the longitudinal direction and the transverse direction, which cross-sectional area can be produced by rotary machining and has a circular feed area at the end of the fixing groove facing the transverse direction. Rotary machining is understood to be a chip removal production process in which a relatively stationary workpiece is subjected to a rotary cutting motion by means of a rotary cutting tool with geometrically defined cutting edges, for example circular sawing with a circular saw blade or milling with a peripheral milling cutter. In the case of rotary cutting, the machining can be carried out by means of a circular cutting motion associated with the tool and any feed motion, where the axis of rotation of the cutting motion maintains its attitude relative to the tool independently of the feed motion. The three-dimensional shape of the locking element can be adapted to the shape of the fixing groove such that the corresponding surfaces can face each other, in particular can lie flat against each other. Preferably, the locking element is based essentially on the basic shape of a cuboid such that the locking element is inserted into the fixing groove outside the circular feed area of the fixing groove, in particular in an immovable manner, whereby the production of the locking element can be more cost-effective. Here, the knowledge is utilized that in order to provide the locking function of the locking element, it is sufficient for the locking element to have a relatively small extension in the transverse direction. For example, the extension of the locking element can be dimensioned essentially only with respect to the locking function and the forces to be borne, whereby it is very likely that the extension of the locking element can be chosen to be smaller than the extension of the fixing groove. Instead of manufacturing the fixing groove with a pin-shaped milling cutter advancing in the transverse direction, the diameter of which corresponds in particular to the extension of the fixing groove in the thickness direction, the fixing groove can be manufactured by circular sawing or by a peripheral milling cutter incorporated into the panel element, since a circular feed area is allowed at the end of the fixing groove. This allows the fixing groove to be produced at lower cost and more quickly.

[0023] In another embodiment, the fixing groove includes a cross-sectional area, in particular a rectangular cross-sectional area, in a transverse plane spanned by the longitudinal direction and the transverse direction, which rectangular cross-sectional area can be produced by milling. For example, in the case of a panel that is very small in the transverse direction, the entire extension of the fixing groove in the transverse direction can thus be utilized to receive the locking element. Thus, it is possible to avoid leaving a free circular feed area.

[0024] Another embodiment of the present invention relates to a method for producing a panel, which can be configured and further developed as described above, wherein a fixing groove is formed by rotary machining using a cutting tool that engages into the panel element at the short side of the panel element and rotates about a rotational axis extending in the thickness direction, wherein the cutting tool engages into the panel element at a certain distance from the first edge and the second edge, then linearly advances in the transverse direction relative to the panel element, and then the cutting tool exits the panel element at a certain distance from the first edge and the second edge. The method can be configured and further developed, especially as described above with reference to the panel. Due to the fixing groove, which extends only over most of the short side due to rotary machining, and the locking element is received in the fixing groove, a fracture-proof panel with good locking on the material can be produced.

[0025] In particular, the cutting tool includes cutting teeth, which include a main cutting edge and two secondary cutting edges, the main cutting edge being in a substantially radial direction relative to the rotational axis, and the two secondary cutting edges being in substantially opposite axial directions, wherein, in addition to the main cutting edge, the two secondary cutting edges engage with the panel element in a chip-removing and / or smoothing manner to produce the fixing groove. The thickness of the cutting teeth in the thickness direction can be substantially wedge-shaped in the circumferential direction, such that the flank surface of the cutting teeth facing the thickness direction can form a clearance surface for the appropriate wedge angle of the secondary cutting edges. The secondary cutting edges and the main cutting edge can share a common rake face. By means of the secondary cutting edges, the surface of the fixing groove generated by the main cutting edge and facing the thickness direction can be finished in the same machining step, thus facilitating the insertion of the locking element into the fixing groove. By smoothing the surfaces facing each other by means of the secondary cutting edges, the dispersion of the surface roughness and the coefficient of surface friction can be reduced.

[0026] Preferably, the cutting tool includes cutting teeth, which have radially extending portions of different widths in the axial direction relative to the rotational axis, wherein, in particular, the cutting teeth have a radial profile for simultaneously producing a receiving space and a fastening space for the fixing groove. This enables a part of the cutting teeth to engage less deeply into the material of the panel element, for example creating a part of the receiving space, while another part of the cutting teeth offset in the axial direction can engage more deeply into the material of the panel element, for example additionally creating a fastening space. Description of the Drawings

[0027] Hereinafter, the present invention will be explained by way of example based on preferred exemplary embodiments with reference to the drawings, wherein the features shown below can each individually or in any combination represent an aspect of the present invention. In the drawings:

[0028] Figure 1 is a schematic top view of the panel end;

[0029] Figure 2 is Figure 1 a schematic sectional view of the panel of;

[0030] Figure 3 is Figure 2 a schematic sectional view of the panel of during the production process; and

[0031] Figure 4 is Figure 1 a schematic detailed sectional view of the panel of, with a locking element inserted. DETAILED DESCRIPTION

[0032] Figure 1 The panel 10 shown can be used to cover a room surface, for example as a floor laminate. The panel 10 can include on one hand a plug groove 12 and on the other hand a plug projection 14 on its respective long sides extending in the longitudinal direction 30. The nominal width B is set between the long sides of the panel 10, where for the nominal width B between the edges at the long sides of the panel 10, the plug groove 12 and the plug projection 14 are ignored and considered non-existent. In particular, the panel 10 includes on one hand a locking hook 16 on the short side extending in the transverse direction 32 and on the other hand a tongue 18 capable of cooperating with the locking hook 16. For example, a fixing groove 20 is formed at the short side having the locking hook 16, and a locking element 22 can be inserted into the fixing groove 20 and become immovable. In this case, the fixing groove 20 does not extend over the entire nominal width B, but only over a partial section b0, such that between the fixing groove 20 and the long side having the plug groove 12, a first strengthening region 24 with an extension t1 is retained in the transverse direction 32, and between the fixing groove 20 and the long side having the plug projection 12, a second strengthening region 26 with an extension t2 is retained in the transverse direction 32. The fixing groove 20 can be produced by a groove cutting machine 40, which engages on the short side of the panel element 28 of the panel 10 and is configured as a circular saw or a circumferential cutting machine, such that a circular feed-out region 31 with an extension b2 in the transverse direction 32 is produced at the end of the fixing groove 20. An extension b1 of the fixing groove 20 is retained between the feed-out regions 31, and this extension b1 can substantially correspond to the extension of the locking element 22 in the transverse direction 32.

[0033] As Figure 2As shown, at different heights in the thickness direction 34 of the panel element 28, the fixing groove 20 can have different depths in the longitudinal direction 30. The fixing groove 20 thus has a receiving space 36 and a fastening space 38. The receiving space 36 abuts against the short side of the panel element 28 in the longitudinal direction 30. The fastening space 38 protrudes from the receiving space 36 into the panel element 28 in the longitudinal direction 30, and their extensions in the thickness direction 34 are different. The extension of the receiving space in the thickness direction 34 is greater than the extension of the fastening space 38 in the thickness direction 34.

[0034] As Figure 3 shown, the stepped fixing groove 20 can be formed by using a slot milling machine or a circumferential cutting machine 40 of the circular saw type. The groove cutting machine 40 includes a cutting tool 42 for this purpose, and a cutting pin tooth 44 is provided on the radially outer side of the cutting tool 42. The cutting teeth 44 are formed radially outward in a stepped manner, so as to obtain a main cutting edge 46 offset in the radial direction. Therefore, the receiving space 36 with a shorter extension in the longitudinal direction 30 and the fastening space 38 with a larger extension in the longitudinal direction 30 can be produced in a common manufacturing step. In addition, the cutting teeth 44 have a secondary cutting edge 48 facing the thickness direction 34, so that the entire fixing groove 20 with a defined surface can be produced. The fixing groove 20 can be spaced apart from the upper side 52 of the panel element 28 by a certain length in the thickness direction 34, so that the cutting tool 42 of the groove cutting machine 40 can be guided past the locking hook 16. At the same time, the fixing groove 20 is spaced far enough from the lower side 50 of the panel element 28 in the thickness direction 34, so that the panel element 28 can also provide sufficient strength in the area of the fixing groove 20. Preferably, the fixing groove 20 is produced by using the groove cutting machine 40 while the upper side 52 of the panel 10 faces downward and the lower side 50 of the panel 10 faces upward, so that the locking hook 16 overlapping with the above-mentioned cutting teeth 44 can discharge the separated chips downward.

[0035] As Figure 4 shown, the locking element 22 can include a fastening protrusion 60, and the fastening protrusion 60 is pressed into the fastening space 38 of the fixing groove 20. If necessary, the locking element 22 can also be pressed into a part of the receiving space 38 of the fixing groove 20 facing the fastening space 38. The locking element 22 includes a locking connection plate having a locking lug 56. The locking connection plate can slide outside another panel during locking with another panel, and can thus rotate elastically in the direction of the receiving space 36 of the fixing groove 20, and optionally rotate all or part of it into the receiving pocket kept free by the locking element 22. When the specified relative posture of the panel 10 relative to another panel is assumed, the locking connection plate 54 can elastically pop out of the receiving space 36, so that the locking lug 56 can engage into the corresponding locking groove 58 and form a lock.

Claims

1. A panel for covering a room surface, comprising: a panel element (28) extending in a longitudinal direction (30) and a transverse direction (32) for transferring a service load introduced at an upper side (52) of the panel element (28) to a lower side (50) of the panel element (28) facing the room surface, wherein the upper side (52) is spaced apart from the lower side (50) in a thickness direction (34); a fixing groove (20) extending in the transverse direction (32) in an end face short side of the panel element (28); and a locking element (22) inserted into or non - movably inserted into the fixing groove (20); characterized in that an extension part b0 of the fixing groove (20) in the transverse direction (32) is 0.50 ≤ b0 / B ≤ 0.97 relative to a nominal width B of the panel element (28) between a first edge of the panel element (28) extending in the longitudinal direction and a second edge of the panel element (28) extending in the longitudinal direction, wherein a first strengthening region (24) with an extension part t1 in the transverse direction (32) is formed between a first end of the fixing groove (20) facing the first edge in the transverse direction (32), wherein a second strengthening region (26) with an extension part t2 in the transverse direction (32) is formed between a second end of the fixing groove (20) facing the first edge in the transverse direction (32), wherein for the first strengthening region (24), 0.005 ≤ t1 / B ≤ 0.090, for the second strengthening region (26), 0.005 ≤ t2 / B ≤ 0.090, provided that t1 + b0 + t2 = B, and wherein the panel element (28) includes a plug groove (12) extending into the panel element (28) at the first edge and a plug protrusion (14) protruding from the panel element (28) at the second edge, wherein 0.75 ≤ t1 / t2 ≤ 0.99, and wherein an extension part b1 of the locking element (22) in the transverse direction is 0.40 ≤ b1 / B ≤ 0.95 relative to the nominal width B of the panel element (28).

2. The panel according to claim 1, wherein The frictional engagement of the locking element (22) in the fixing groove (20) is achieved only by a clamping force directed towards the thickness direction (34).

3. The panel according to claim 1 or 2, characterized in that, The locking element (22) includes a locking connection plate (54) that can be elastically bent at least partially in a direction entering the fixing groove (20).

4. The panel according to claim 1 or 2, characterized in that, The fixing groove (20) includes a receiving space (36) and a fastening space (38). The receiving space (36) is adjacent to the end face of the short side, and the receiving space (36) is for receiving a part of the locking element (22) or for temporarily receiving the elastic flexible locking connecting plate (54) of the locking element (22). The fastening space (38) is adjacent to one side of the receiving space (36) away from the end face. The fastening space (38) is for fastening the fastening protrusion (60) of the locking element (22) in a frictional and / or form-fitting manner. Among them, the extension of the fastening space (38) in the thickness direction (34) is less than the extension of the receiving space (36) in the thickness direction (34).

5. The panel according to claim 4, wherein The locking element (22) abuts against two planes of the receiving space (36) facing the thickness direction (34), or abuts with a clamping force. Among them, the locking element (22) includes a receiving pocket, and the receiving pocket extends into the receiving space (36) for temporarily receiving the elastically bendable locking connecting plate (54) of the locking element (22).

6. The panel according to claim 1 or 2, characterized in that, The panel element (28) includes a locking hook (16) at the short side where the fixing groove (20) is formed. The locking hook (16) protrudes from the short side of the panel element along the longitudinal direction (30) for locking into the fixing groove (20) of another panel.

7. The panel according to claim 1 or 2, characterized in that, In the cross-sectional plane spanned by the longitudinal direction (30) and the transverse direction (32), the fixing groove (20) includes a circular feeding area at the end of the fixing groove (20) facing the transverse direction (32), and the circular feeding area is generated by rotary machining.

8. The panel according to claim 1 or 2, characterized in that, In the cross-sectional plane spanned by the longitudinal direction (30) and the transverse direction (32), the fixing groove (20) includes a rectangular cross-sectional area, and the rectangular cross-sectional area is generated by milling.

9. A method for producing a panel according to claim 1 or 2, wherein, The fixing groove (20) is formed by using a cutting tool (42) through rotary machining. The cutting tool (42) engages with the panel element (28) at the short side of the panel element and rotates around a rotation axis extending along the thickness direction (34). Among them, the cutting tool (42) engages with the panel element (28) at a certain distance from the first edge and the second edge. Subsequently, it linearly moves relative to the panel element (28) in the transverse direction (32), and subsequently, the cutting tool (42) withdraws from the panel element (28) spaced from the first edge and the second edge.

10. The method according to claim 9, wherein The cutting tool (42) includes cutting teeth (44), and the cutting teeth (44) include a main cutting edge (46) and two secondary cutting edges (48) relative to the rotation axis; the main cutting edge (46) faces a substantially radial direction, and the two secondary cutting edges (48) face substantially opposite axial directions, wherein, in addition to the main cutting edge (46), the two secondary cutting edges (48) are engaged in the panel element (28) in a chip-removing and / or smoothing manner to produce the fixing groove (20).

11. The method according to claim 9, wherein, The cutting tool (42) includes cutting teeth (44), and the cutting teeth (44) have radially extending portions with different widths in the axial direction relative to the rotation axis, wherein the cutting teeth (44) have a radial profile for simultaneously producing a receiving space (36) and a fastening space (38) of the fixing groove (20).

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