CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a 371 of International application PCT/EP2020/058468, filed Mar. 26, 2020, which claims priority of DE 20 2019 101 807.0, filed Mar. 29, 2019, the priority of these applications is hereby claimed and these applications are incorporated herein by reference.

BACKGROUND OF THE INVENTION

The invention concerns a panel comprising a panel core, a panel top side, a panel underside and at least one edge pair of mutually opposite complementary panel edges provided with complementary locking means, wherein the complementary locking means are of such a configuration that in the assembled state of two of those panels beneath a visible join by means of the assembled complementary locking means both a locking action of the panel edges can be achieved in a direction perpendicular to the panel top side and also a locking action can be achieved to prevent the panels from moving apart and more specifically away from each other within the panel plane in a direction perpendicular to the locked panel edges, with the proviso that the panel edges provided with the complementary locking means have an upper portion and a lower portion in relation to the thickness of the panel, wherein the complementary locking means are arranged and formed in the lower portion of the panel edges, wherein the upper portion of the panel edges is provided for the formation of the upper join region including the visible part of the join and for that purpose the upper portion at each panel edge of the edge pair has an edge break which in the assembled state of two of said panels forms a recessed join, wherein the edge breaks of the complementary panel edges are of different sizes in the upper portion of the panel edges, and in the assembled state of two complementary panel edges the larger edge break is covered by the smaller edge break.

The assembled state of panels or complementary panel edges is basically used to mean the target or reference state.

WO 97/47834 A1 discloses a panel which in the upper portion has a join configuration without a recess and in the lower portion has positively locking fixing means in the form of a groove profile and a tongue profile. WO 2008/053333 discloses an example of a panel having complementary panel edges which in an upper portion relative to the thickness of the panel have a configuration with edge breaks or bevels of differing sizes in the form of a larger chamfer and a smaller chamfer. In that state of the art the upper portions of the panel edges are further of such a configuration that two of those panels in the assembled state form a V-join, wherein the larger chamfer is partially covered by the smaller chamfer. In addition that state of the art defines a neutral position of the panel edges relative to each other, out of which the panel edges can move closer towards each other or further away from each other. In the neutral position the V-join is not closed at its join base, but a gap remains there.

The configuration of the upper portion of the panel edge, known from that state of the art, is deemed to be inappropriate because of the open nature of the join. Dirt and moisture can easily penetrate to the panel core.

The complementary locking means provided in the same state of the art in the lower portion of the complementary panel edges appear less able to carry a load and they are of unsatisfactory durability.

SUMMARY OF THE INVENTION

The object of the invention is to propose a panel which in the upper portion of the panel edges is of an improved configuration with edge breaks.

According to the invention that object is attained in that an obtuse butting surface is provided at a lower end of the larger edge break.

The two edge breaks can be in the form of a bevel or chamfer, a radius or a hollow fillet and so forth.

Desirably provided in the upper portion of the panel edges at that panel edge having the smaller edge break is a counterpart butting surface cooperating with the obtuse butting surface, that is provided beneath the larger edge break.

In addition the pairing provided in the upper portion of the panel edges and comprising the obtuse butting surface and the counterpart butting surface cooperates with the locking means which are arranged in the lower portion of the panel edges and with which the locking action to prevent the panels from moving apart within the panel plane and perpendicularly to the locked panel edges is implemented. More specifically desirably the locking means disposed in the lower portion are so designed that the obtuse butting surface can be held in contact with the counterpart butting surface. In that way the closed nature of the join, that is wanted in the upper portion of the panel edge, is promoted by the locking means disposed in the lower portion.

The panel edge having the smaller of the two edge breaks has beneath that smaller edge break an undercut counterpart surface for the covered part of the larger edge break. Desirably the covered part of the larger edge break is in surface contact with the undercut counterpart surface. That also enhances the closed nature of the join and resists the ingress of dirt and moisture.

An advantageous development provides that the counterpart butting surface provided beneath the smaller edge break is of such a configuration that it has an oversize in an upper region. By virtue thereof, in the assembled state of two panels, pressing with the butting surface of the complementary panel edge can be produced at the upper region of the counterpart butting surface.

The advantage can be further improved if the obtuse butting surface and the counterpart butting surface are so arranged that in the assembled state of two complementary panel edges a wedge-shaped gap is formed between the obtuse butting surface and the counterpart butting surface, such that the tip of the wedge-shaped gap faces upwardly towards the panel top side. The wedge-shaped gap between the butting surface and the counterpart butting surface promotes a relative movement of two assembled locked panels. The panels can involve a kink as a pivot point along the locked panel edges if for example they lie on an uneven surface. In that case locked panels can assume a position relative to each other, in which their panel surfaces are at an angle >180° relative to each other. In that case the wedge-shaped gap within the locked panel edges provides space for the required angular movement of the panel edges. The obtuse butting surface and the counterpart butting surface keep in contact and any opening of the join is counteracted thereby.

To provide a closed join it is advantageous if in the assembled state of two complementary panel edges the obtuse butting surface and the counterpart butting surface are in contact with each other at the tip of the wedge-shaped gap.

The wedge-shaped gap can have a wedge angle in the region of 0° to 10° and preferably 1° to 5° wherein a central axis of the wedge-shaped gap, that halves the wedge angle, is either arranged perpendicularly to the panel surface or is arranged in an angle range of ±5° relative to the perpendicular to the panel top side.

A development provides that in the lower portion of the complementary panel edges the complementary locking means are in the form of complementary hook profiles, namely an upwardly open receiving hook and a downwardly open arresting hook, that both complementary hook profiles have holding surfaces provided integrally on the panel core and by means of which the locking action to prevent the panels moving apart within the panel plane away from each other in a direction perpendicular to the locked panel edges can be achieved and that there is provided a separate locking element for the locking action in the vertical direction perpendicular to the panel top side, as defined in EP 1 415 056 B1 or proposed in WO 2011/087425 A1. Reference is hereby directed to the examples of the configuration for separate locking elements and the arrangement thereof on a panel, as defined in the two above-mentioned publications, and that technical teaching is incorporated herein.

In addition the separate locking element can be mounted at one of the complementary panel edges and can have a latching means with which it is latchable in a latching contour of the complementary panel edge.

Another technical solution as the above-mentioned locking means with hook profiles manages without a separate locking element and provides that provided in the lower portion of the complementary panel edges are locking means including a groove profile and a complementary tongue profile, the groove profile and the complementary tongue profile have holding surfaces, by means of which the locking action preventing the panels from moving apart within the panel plane away from each other in a direction perpendicular to the locked panel edges can be achieved and the tongue profile at its tongue top side has a contact surface and the groove profile at an upper groove wall has a complementary internal surface whereby in the assembled state the locking action can be achieved in the vertical direction perpendicular to the panel top side.

The configuration of the lower portion of the complementary panel edges with locking means, when they are in the form of a groove profile and a complementary tongue profile, as described hereinbefore, is viewed as an independent invention which alternatively can manage without the above-proposed configuration of the upper portion of the complementary panel edges. In the upper portion the panel edges can then be of any configuration, for example it is possible to dispense with any edge break or bevel, so that no recessed join is present at the surface between two locked panels. That equally applies to all developments hereinafter of the panel with a groove profile and a complementary tongue profile.

Desirably the lower groove wall projects distally from the panel edge further than the upper groove wall, wherein a holding edge is provided at the free end of the lower groove wall and the holding surface for the locking action to prevent the panels moving apart in the panel plane is provided at said holding edge.

The groove profile and the tongue profile are adapted for a snap locking action in which locking is effected by level displacement of two identical panels with the panel edges perpendicular towards each other and/or are so adapted that a panel is lockable to an identical panel by a pivotal movement (pivotal locking), in that the panel is fitted in an inclined plane relative to the panel plane of the identical other panel and the tongue profile is lockable by subsequent pivotal movement of the inclinedly fitted panel into the plane of the other panel with its groove profile.

An additional improvement is achieved if one of the holding surfaces for the locking action to prevent level movement of the panels apart is arranged at the lower groove wall of the groove profile and said holding surface is disposed in the region of the lower longer groove wall which extends distally over the length of the upper groove wall, said holding surface is in the form of an inclined plane which drops towards the groove bottom of the groove profile and the holding surface of the tongue profile, that is complementary to the holding surface of the groove profile, at the tongue underside, is also an inclined plane which in the assembled state bears in surface relationship against the holding surface of the groove profile.

Handling can be improved if the groove profile and the tongue profile are adapted for pivotal locking, wherein provided at the tongue underside is a flat lower shoulder surface oriented parallel to the panel top side, the groove profile at a lower groove wall has a contact surface for the shoulder surface of the tongue profile, and wherein the contact surface is also flat and parallel to the panel top side.

For the purposes of good locking in a vertical direction the contact surface on the tongue top side can be parallel to the panel surface and the complementary internal surface of the upper groove wall of the groove profile can be arranged parallel to the panel top side, for that purpose.

The contact surface of the tongue top side has a distal end and a proximal end and likewise the shoulder surface of the tongue underside has a distal end and a proximal end, wherein desirably a spacing is provided between the distal end of the shoulder surface and the proximal end of the contact surface (pivotal connection).

For improving stability of the groove profile the lower groove wall rises out of the plane of the contact surface towards the groove bottom.

An alternative provides that the groove profile and the tongue profile are adapted for snapping locking, wherein at its tongue underside the tongue profile has a proximal lower shoulder surface and distally (near the free end of the tongue profile) it has a carrying surface, the complementary groove profile has a support surface for supporting the carrying surface of the tongue profile at the lower groove wall, and the complementary groove profile is provided with a matching contact surface for the lower shoulder surface of the tongue profile. With the concept of the snap locking action in respect of two panels the panel edges with the groove profile and the tongue profile are moved towards each other with a translatory movement in a direction perpendicular to the longitudinal extent of the complementary panel edges. In order in that case to be able to produce a positively locking connection between the tongue profile and the groove profile those locking means must permit and be able to endure adequate elastic deformation.

The carrying surface of the tongue profile and also the associated support surface of the groove profile are desirably arranged parallel to the panel top side. In that case the support surface is desirably arranged in a region of the lower groove wall, that is opposite to the upper groove wall. If the panel top side in the region of locked panel edges is subjected to a load which exerts a pressure on the upper groove wall then the force is transmitted by way of the internal surface of the upper groove wall to the contact surface of the tongue top side and through the tongue profile. At the tongue underside the force is transmitted from the carrying surface thereof into the support surface of the lower groove wall which in turn carries the force downwardly into a surface on which the panel is lying.

The contact surface provided on the groove profile for the lower shoulder surface of the tongue profile can be arranged in the region of the lower groove wall, that projects distally further from the panel edge with respect to the upper groove wall.

The contact surface provided for the lower shoulder surface of the tongue profile on the groove profile is desirably flat. It can also be formed with an inclination directed downwardly in the distal direction. The inclination is preferably in an angular range of 2° to 10° with respect to the panel top side. The reason for the inclination is in conjunction with the configuration which has the lower groove wall in the region of its free end, as described in greater detail hereinafter.

For the configuration of the panel, that is provided for the purposes of a snapping connection, the contact surface at the tongue top side is desirably arranged parallel relative to the panel top side, wherein the internal surface complementary thereto of the upper groove wall of the groove profile is then also arranged parallel to the panel top side, and wherein the internal surface of the upper groove wall is larger than the support surface at the lower groove wall. Equally the carrying surface at the tongue underside is smaller than the contact surface at the tongue top side. Therefore a force applied from the panel top side is transmitted downwardly into the tongue profile from the upper groove wall by way of a first surface pair. The first surface pair comprises the internal surface of the upper groove wall and the contact surface of the tongue top side. The force from the tongue profile is then further transmitted downwardly by means of a second surface pair comprising the carrying surface of the tongue underside and the support surface of the lower groove wall. The size of the contact surface of the second surface pair is less than the size of the contact surface of the first surface pair. The reduced contact surface of the second surface pair is responsible for the improvement in the strength of the lower groove wall.

Preferably the centre of the internal surface of the upper groove wall is arranged closer to the groove bottom than the centre of the support surface of the lower groove wall. That also serves to enhance the strength of the lower groove wall.

At the inside of the upper groove wall towards the free end thereof the groove profile can have a cut-free relief portion which preferably has an inclined relief surface. In that arrangement the relief portion is desirably so adapted that the width of the groove profile increases towards the free end and forms an enlarged entry opening. The entry opening which is enlarged in that way of the groove profile acts for a tongue profile which is moved with a translatory movement in the direction of the groove profile, like a funnel. The tongue profile then first comes into contact with the relief surface at its tongue top side.

The free end of the tongue profile can be in the form of an obtuse wedge-shaped cross-section, wherein the wedge surface promotes guidance and centring along the inclined relief surface of the upper groove wall to facilitate insertion of the tongue profile into the groove profile.

The wedge surface at the tongue underside is longer and provides a larger cut-free relief portion than the wedge surface at the tongue top side. The relief portion at the tongue underside serves to provide space for the lower groove wall which is to be reinforced by the lower groove wall being of an increasing wall thickness towards the groove bottom.

That holding edge which is provided at the free end of the lower groove wall is desirably provided with an edge surface arranged at a level which makes it possible for implementing a snapping connection to slidingly move the tongue underside of a complementary panel over the edge surface and in so doing bring the tongue top side of the tongue profile into contact with the relief portion at the inside of the upper groove wall. The tongue top side is supported by the contact at the upper groove wall, which benefits the further joining movement. In the further joining movement the tongue profile is moved forwardly deeper into the groove profile, in which case the shoulder surface of the tongue profile presses against the edge surface of the holding edge of the lower groove wall and bends the lower groove wall elastically downwardly in the direction of the panel underside. The tongue profile is supported at the tongue top side at the inside of the strong upper groove wall. By virtue of its smaller distal extent the upper groove wall is less yielding than the lower groove wall. In addition the wall thickness of the upper groove wall is greater than that of the lower groove wall, which promotes the desired higher stiffness of the upper groove wall in comparison with the lower groove wall.

In addition the edge surface is desirably provided with an inclination adapted to the inclination of the shoulder surface of the tongue underside, or is identical to the inclination of the contact surface of the lower groove wall. This ensures that, at the beginning of the translatory joining movement, the shoulder surface of the tongue underside is in surface contact with the edge surface and pressure can be uniformly applied to the edge surface to begin elastic bending of the lower groove wall.

The tongue underside can have a concave contour between its carrying surface and its shoulder surface, wherein in the assembled state of two panels a free space is formed between the concave contour and the lower groove wall. The concave contour benefits the beginning of the joining movement. It is known from the state of the art that, for the beginning of the joining movement, firstly the tongue underside is only placed on the holding edge. It has now been found in that respect that the tongue underside can be so inappropriately inclined that it can already slip off entirely at the beginning of the joining movement when it has only been laid on the edge surface of the holding edge. In the case of a long panel it may be difficult to lay the tongue underside correctly on the holding edge over the entire length of the panel. The concave contour in that region at the tongue underside makes it easier to simply and securely place the tongue profile on the holding edge and to prevent it from slipping off the holding edge.

Furthermore, by virtue of the concave contour at the tongue underside, there is a free space towards the lower groove wall. The free space makes it easier for the surface pairing comprising the carrying surface and the support surface to bear against each other and at the same time for the pairing comprising the shoulder surface and the contact surface to bear against each other in surface contact. The free space further leaves space for particles which can occur everywhere on the lower groove wall. Such particles could interfere with fitment of the above-mentioned surface pairing and adversely affect the functionality of the locking configuration.

In the assembled state of two complementary panel edges at least three pairings of contact surfaces can be formed between the groove profile and the tongue profile. A contact surface pairing comprises the contact surface of the tongue top side paired with the internal surface of the upper groove wall. At least one second contact surface pairing comprises the shoulder surface of the tongue underside paired with the contact surface of the lower groove wall. A third contact surface pairing can comprise the carrying surface of the tongue underside paired with the support surface of the lower groove wall. In the assembled state of two panels a free space is formed between each of said contact surface pairings.

For a panel with a lower groove wall which, by virtue of its wall thickness, would be excessively non-yielding for making a snapping connection a slot can be provided beneath the groove bottom of the groove profile in the region of the proximal end of the lower groove wall at the panel underside, which slot extends parallel to the panel edge to increase the yielding flexibility of the lower groove wall. Desirably the slot has a rounded bottom, which reduces notching stresses. The slot can include parallel side walls or the slot can be of a substantially trapezoidal cross-section.

