Patent Application
20200149289
The disclosure generally relates to the field of mechanical locking systems for floor panels and building panels. The disclosure includes panels, floorboards, locking systems and production methods.
Embodiments of the present disclosure are particularly suitable for use in floating floors, which are formed of floor panels having one or more upper layers comprising, e.g., thermoplastic or thermosetting material or wood veneer, an intermediate core of wood-fibre-based material or plastic material and preferably a lower balancing layer on the rear side of the core. Embodiments of the disclosure may also be used for joining building panels which preferably contain a board material for instance wall panels, ceilings, furniture components and similar.
The following description of prior-art technique, problems of known systems and objects and features of the disclosure will therefore, as a non-restrictive example, be aimed above all at this field of application and in particular at laminate floors comprising an HDF core and formed as rectangular floor panels with long and shorts edges intended to be mechanically joined to each other on both long and short edges.
The long and short edges are mainly used to simplify the description of the disclosure. The panels may be square. Floor panels are generally produced with the surface layer pointing downwards in order to eliminate thickness tolerances of the core material. Some embodiments and production methods are shown with the surface pointing upwards in order to simplify the description.
It should be emphasized that embodiments of the disclosure may be used in any floor panel on long and/or short edges and it may be combined with all types of known locking systems on long or short edges that lock the panels in the horizontal and/or vertical direction.
Relevant parts of this background description are also a part of embodiments of the disclosed invention.
Several floor panels on the market are installed in a floating manner with mechanical locking systems formed at the long and short edges. These systems comprise locking means, which lock the panels horizontally and vertically. The mechanical locking systems are usually formed by machining of the core of the panel. Alternatively, parts of the locking system may be formed of a separate material, for instance aluminum or plastic material, which is integrated with the floor panel, i.e. joined with the floor panel in connection with the manufacture thereof.
Laminate flooring usually comprise a 6-8 mm wood based core, a 0.2 mm thick upper decorative surface layer of laminate and a 0.1 mm thick lower balancing layer. The laminate surface and the balancing layer comprise melamine-impregnated paper. The most common core material is fibreboard with high density and good stability usually called HDF—High Density Fibreboard. The impregnated surface and balancing papers are laminated to the core with heat and pressure. HDF material is hard and has a low flexibility, especially in the vertical direction perpendicular to the fibre orientation.
Recently a new type of powder based laminate floors has been introduced. Impregnated paper is replaced with a dry powder mix comprising wood fibres, melamine particles, aluminum oxide and pigments. The powder is applied on an HDF core and cured under heat and pressure. Generally high quality HDF is used with a high resin content and low water swelling. Advanced decors may be formed with digital printing. Water based ink is injected into the powder prior to pressing.
Luxury vinyl tile, LVT, flooring with a thickness of 3-6 mm usually comprises a transparent wear layer which may be coated with an ultraviolet, UV, cured polyurethane, PU, lacquer and a decorative plastic foil under the transparent foil. The wear layer and the decorative foil are laminated to one or several core layers comprising a mix of thermoplastic material and mineral fillers. The plastic core may be rather soft and flexible but also rather rigid depending on the filler content.
Wood Plastic Composite floors, generally referred to as WPC floors, are similar to LVT floors. The core comprises thermosetting material mixed with wood fibre fillers and is generally stronger and much more rigid than the mineral based LVT core.
Thermoplastic material such as PVC, PP or PE may be combined with a mix of wood fibres and mineral particles and this may provide a wide variety of floor panels with different densities and flexibilities.
Moisture resistant HDF with a high resin content, and WPC floors, comprise stronger and more flexible core materials than conventional HDF based laminate floors and they are generally produced with a lower thickness.
The above mentioned floor types comprise different core materials with different flexibility, density and strengths. Locking systems formed in one piece with the core must be adapted to such different material properties in order to provide a strong and cost efficient locking function.
In the following text, the visible surface of the installed floor panel is called “front side” or “floor surface”, while the opposite side of the floor panel, facing the sub floor, is called “rear side”. The edge between the front and rear side is called “joint edge”. By “horizontal plane” is meant a plane, which extends parallel to the front side. Immediately juxtaposed upper parts of two adjacent joint edges of two joined floor panels together define a “vertical plane” perpendicular to the horizontal plane. By “vertical locking” is meant locking parallel to the vertical plane. By “horizontal locking” is meant locking parallel to the horizontal plane.
By “up” is meant towards the front side, by “down” towards the rear side, by “inwardly” mainly horizontally towards an inner and center part of the panel and by “outwardly” mainly horizontally away from the center part of the panel.
By “essentially vertical” surface or wall is meant a surface or a wall that is inclined less than 45 degrees against a vertical plane.
By “essentially horizontal” surface is meant a surface that is inclined less than 45 degrees against a horizontal plane.
By locking angle of a surface locking panels in the horizontal direction is meant the angle of the surface relative a vertical plane
By locking angle of a surface locking panels in the vertical direction is meant the angle of the surface relative a horizontal plane.
A tangent line defines the inclination of a curved wall or surface.
For mechanical joining of long edges as well as short edges in the vertical direction and horizontal direction perpendicular to the edges several methods may be used. One of the most used methods is the angle-snap method. The long edges are installed by angling. Horizontal snapping locks the short edges. The vertical connection is generally a tongue and a groove and the horizontal connection is a strip with a locking element in one edge that cooperates with a locking groove in the adjacent edge. Locking by snapping is obtained with a flexible strip that during the initial stage of locking bends downwards and during the final stage of locking snaps upwards such that the locking element is inserted into the locking groove.
Similar locking systems may also be produced with a rigid strip and they are connected with an angling-angling method where both short and long edges are angled into a locked position.
Advanced so-called “fold down locking systems” with a separate and flexible tongue on a short edge, generally called “5G systems”, have been introduced where both the long and short edges are locked with an angling action. A floor panel of this type is presented in WO 2006/043893. It discloses a floor panel with a short edge locking system comprising a locking element cooperating with a locking groove, for horizontal locking, and a flexible bow shaped so called “banana tongue” cooperating with a tongue groove, for locking in a vertical direction. The flexible bow shaped tongue is inserted during production into a displacement groove formed at the edge. The tongue bends horizontally along the edge during connection and makes it possible to install the panels by vertical movement. Long edges are connected with angling and a vertical scissor movement caused by the same angling action connects short edges. The snapping resistance is low and only a low thumb pressure is needed to press the short edges together during the final stage of the angling. Such a locking is generally referred to as “vertical folding”.
Similar floor panels are further described in WO 2007/015669. This invention provides a fold down locking system with an improved flexible tongue so called “bristle tongue” comprising a straight outer tongue edge over substantially the whole length of the tongue. An inner part of the tongue comprises bendable protrusions extending horizontally along the tongue body.
The above known fold down “5G system” has been very successful and has captured a major market share of the premium world laminate and wood flooring markets. The locking is strong and reliable mainly due to the flexibility and pretension of the separate flexible tongue that allows a locking with large overlapping essentially horizontal locking surfaces.
The 5G system and similar system have been less successful in the low priced market segments. The major reason is that the cost of the separate tongues and investments in special inserting equipment that is needed to insert a flexible tongue into a displacement groove are regarded as rather high in relation to the rather low price of the floor panels.
Several attempts have been made to provide a fold down locking system based on a vertical snapping function that may be produced in one piece with the core in the same way as the one piece horizontal snap systems. All such attempts have failed especially when a floor panel comprises an HDF core. This is not a coincidence. The failure is based on major problems related to material properties and production methods. Several of the known locking systems are based on theoretical geometries and designs that have not been tested in industrial applications. One of the main reasons behind the failure is that bending of vertically protruding parts that are used for the vertical locking of edges is limited to about 50% of the floor thickness or to about 4 mm in an 8 mm thick laminate floor panel. As comparison it may be mentioned that a protruding strip for horizontal snapping may extend over a substantial distance from the upper edge and may protrude 8-10 mm beyond the upper edge. This may be used to facilitate a downward bending of the strip and the locking element. Other disadvantages compared to horizontal snapping are that HDF comprises a fibre orientation substantially parallel with the floor surface. The material properties are such that bending of horizontally protruding parts is easier to accomplish than bending of vertically protruding parts. Furthermore, lower parts of an HDF board comprise a higher density and a higher resin content than middle parts and such properties are also favorable for the horizontal snapping systems where the strip is formed in the lower part of the core.
Another circumstance that has supported market introduction of the horizontal snap systems is the fact that a hammer and a knocking block may be used to snap the short edges. Fold down systems are so called tool-less systems and the vertical locking must be accomplished with hand pressure only.
It would be a major advantage if a one-piece fold down locking system may be formed with a quality and locking function similar to the advanced 5G systems.
An objective of embodiments of the present disclosure is to provide an improved and more cost efficient fold down locking system for vertical and horizontal locking of adjacent panels wherein the locking system is produced in one piece with the core.
A first specific objective is to provide a locking system wherein a horizontally extending flexible strip may be used to accomplish the vertical and horizontal locking.
A second specific objective is to provide a locking system with essentially horizontally extending locking surfaces for the vertical locking such that a strong locking force may be obtained in the vertical direction.
A third specific objective is to prevent separation forces between the edges during locking and to decrease the snapping resistance such that a tool-less installation may be obtained with low pressure against the short edges.
A fourth specific objective is to provide a cost efficient method to form locking elements in a double-end tenor comprising a lower chain and an upper belt that displace the panel in relation to several tool stations.
The above objects may be achieved by embodiments of the disclosure.
According to a first aspect of the disclosure a set of essentially identical floor panels are provided with a mechanical locking system comprising a strip extending horizontally from a lower part of a first edge and a downwardly open locking groove formed in an adjacent second edge. The strip comprises an upwardly protruding locking element that is configured to cooperate with the locking groove and locks the first and the second edge in a horizontal direction parallel to a main plane of the first and the second panel and in a vertical direction perpendicularly to the horizontal direction. The locking system is configured to be locked with a vertical displacement of the second edge against the first edge wherein the strip, preferably an outer portion of the strip, during an initial stage of the vertical displacement is configured to bend upwards towards the second panel and during a final stage of the vertical displacement is configured to bend downwards towards its initial unlocked position.
An upper portion of the locking element may be configured to be displaced during locking into a space provided between an outer groove wall of the locking groove and an inner surface of the locking element. The displacement may be caused by at least one of a bending, a compression and a twisting of the strip. Optionally, the upper portion of the locking element may during locking be further configured to be displaced out from the space.
Bending may comprise rotation and/or a displacement of at least portions of the strip.
According to one embodiment, the space between the outer groove wall and the inner surface is a cavity arranged in the inner surface of the locking element. According to another embodiment, the space is a cavity arranged in the outer groove wall of the locking groove. According to yet another embodiment, the space is partly a cavity arranged in the inner surface and partly a cavity arranged in the outer groove wall.
The strip may be configured to bend upwards towards a portion of a front side of the second panel. The portion may be an outer portion of the front side.
Optionally, the upward and/or downward bending of the strip may be combined with at least one of a twisting or a compression of the strip.
The strip may be configured to bend upwards from the unlocked position to an end position. Moreover, the strip may be configured to bend downwards from the end position and at least partly back to the unlocked position. In a non-limiting example, an outer, lower portion of the strip is displaced vertically upwards from the unlocked position to the end position by a first distance and then is displaced vertically downwards by a second distance, wherein the second distance is between 10% and 95% of the first distance, e.g. 40% or 50%. In another non-limiting example, the strip bends completely back to a position corresponding to the unlocked position so that the second distance is essentially the same as the first distance.
The first and second panels may comprise a pair of parallel short edges and a pair of parallel long edges, wherein the long edges are perpendicular to the short edges. The first and second edges may be short edges.
The main plane of the first and the second panel may be a horizontal plane that is essentially parallel with the front side and/or the rear side of the first and/or the second panel.
By a vertical displacement is meant that the edges of the panels are displaced against each other at least in a vertical direction. Optionally, however, the vertical displacement may also be combined with an angling action. According to one embodiment, the vertical displacement is a vertical scissor movement caused by the same angling action that is used to connect the edges of the panels that are perpendicular to the first and the second edges. For example, the first and second edges may be short edges and the perpendicular edges may be long edges. According to another embodiment, front sides of the first and second panels are essentially parallel to each other during the vertical displacement.
The first and the second edge may comprise a first edge section and a second edge section along the first and the second edge, wherein a cross section of the locking groove or a cross section of the locking element varies along the first edge and/or the second edge, in a locked position.
The cross section of the locking groove or of the locking element may be a cross section as seen from a side view of the floor panels.
There may be at least one first edge section and at least one second edge section. A shape of the each of the first edge sections may be similar. Moreover, a shape of each of the second edge sections may be similar. Alternatively, the shapes of the first edge sections and/or the second edge sections may vary.
The first edge sections and the second edge sections may be arranged alternately along the first and the second edge.
There may be a smooth transition between the first and the second edge sections along the edge. Alternatively, the transition between the first and the second edge sections along the edge may be stepped.
According to one embodiment, a first edge section is arranged at a first and/or a second corner section of the first and second edges. According to one embodiment, a second edge section is arranged at a first and/or a second corner section of the first and second edges. In any of these embodiments, the first and second corner sections may be arranged adjacent to long edges of the panels.
According to one embodiment, the first and second edges are locked vertically by means of engagement of an upper locking surface provided on an outer surface of the locking element and a lower locking surface provided on an inner groove wall of the locking groove. In one example, the upper locking surface is provided along the entire first edge and the lower locking surface is provided along a part of the second edge. In another example, the upper locking surface is provided along a part of the first edge and the lower locking surface is provided along the entire second edge.
During the final stage the locking element may be snapped into the locked position such that the upper and lower locking surfaces engage with each other in the locking position. Alternatively, the locking element may assume the locked position by means of a smooth displacement upwards and/or downwards such that the upper and lower locking surfaces engage with each other in the locking position. For example, the latter may be achieved with a beveled upper and/or lower locking surface. The strip may also be pressed down by a lower part of the second panel that presses against an upper part of the protruding strip and/or the locking element.
According to a second aspect of the disclosure a set of essentially identical rectangular floor panels each comprising long edges and a first short edge and a second short edge are provided. The first short edge and the second short edge are provided with a mechanical locking system comprising a strip extending horizontally from a lower part of a first short edge and a downwardly open locking groove formed in the second short edge. The strip comprises an upwardly protruding locking element that is configured to cooperate with the locking groove for locking the first short edge and the second short edge in a horizontal direction parallel to the main plane of the panels and in a vertical direction perpendicularly to the horizontal direction. The locking element comprises an inner surface, an outer surface and a top surface. The inner surface is positioned closer to an upper edge of the first panel than the outer surface. The locking groove comprises an outer groove wall, an inner groove wall and an upper groove wall, the outer groove wall being positioned closer to an upper edge of the second panel than the inner groove wall. The locking element comprises an upper locking surface and the locking groove comprises a lower locking surface. In a locked position the first short edge and the second short edge comprise a first and a second joint edge section located along the first short edge and the second short edge. The first edge section is configured such that the outer groove wall of the locking groove and the inner surface of the locking element along are in contact with each other along a horizontal plane HP and lock the first short edge and the second short edge horizontally, and the second edge section is configured such that along the horizontal plane HP there is a space between the outer groove wall of the locking groove and the inner surface of the locking element. The upper locking surface of the locking element and the lower locking surface of the locking groove are configured to be in contact with each other and to lock the first short edge and the second short edge vertically.
Embodiments of the space between the outer groove wall and the inner surface are largely analogous to the embodiments described above in relation to the first aspect, wherein reference is made to the above. In addition, a length of the space in a length direction of the short edges may correspond to a length of the second edge section. Alternatively, the length of the space may be longer than the length of the second edge section.
The upper locking surface of the locking element and the lower locking surface of the locking groove may be configured to be in contact with each other in the second edge section.
The upper locking surface and the lower locking surface form an overlap in a direction parallel with the main plane of the panels and perpendicularly to the short edges. Preferably, there is an overlap only along a portion of the short edges, e.g. in the second edge section(s). In a first example, the overlap is constant along the short edges. More specifically, the overlap is constant in the second edge section(s). In a second example, the overlap varies along the short edges. The varying overlap may be periodic with a constant periodicity along the second edge section(s).
According to one embodiment, the upper locking surface extends along the entire first short edge. In a non-limiting example, there is no lower locking surface provided in the first edge section.
According to one embodiment, the lower locking surface extends along the entire second short edge. In a non-limiting example, there is no upper locking surface provided in the first edge section.
The upper locking surface or the lower locking surface may extend along a portion of the first and second short edge, respectively.
According to a non-limiting embodiment, the upper locking surface is arranged only in a middle section of the first short edge and the lower locking surface is provided along the entire second short edge. Thereby, the upper locking surface is missing from corner sections of the first short edge, wherein the middle section is a second edge section and the corner sections are first edge sections, the middle section being arranged between the corner sections. The overlap is thereby formed only in the middle section. According to this embodiment, the space is formed as a cavity in a middle portion of the outer groove wall and/or in a middle portion of the inner surface.
The upper edge of a panel may be a portion of the panel along a short edge thereof. The upper edge may be closer to the front side than the rear side of the panel. Moreover, the upper edge of the first panel may be provided in a side wall of an indentation provided along the first short edge of the first panel. A projection along the second short edge of the second panel may be adapted to be inserted in the indentation. Moreover, the upper edge of the second panel may be provided in the second short edge of the second panel.
The first edge section may be located closer to a long edge than the second edge section. Alternatively, the second edge section may be located closer to a long edge than the first edge section. The first and/or second edge sections may be arranged at corner sections in precise analogy to the first aspect explained above.
The locking system may be configured to be locked with a vertical displacement of the second short edge against the first short edge. The concept of “vertical displacement” has been defined above in relation to the first aspect.
The locking system may be configured such that a vertical displacement of the second short edge against the first short edge during an initial stage of the vertical displacement bends the strip upwards towards the second panel such that the upper locking surface and lower locking surface overlap each other.
The strip may be configured to bend upwards towards a portion of a front side of the second panel. The portion may be an outer portion of the front side. The upward bending of the strip may comprise at least one of an upward vertical displacement, a horizontal displacement inwards, and a rotation. Optionally, the upward bending may be combined with a twisting and/or a compression of the strip.
The lower locking surface may be essentially horizontal. Alternatively, the lower locking surface may be inclined. The angle of the lower locking surface with respect to a main plane of the second panel may be between 0° and 45° degrees, e.g. 15°, 20° or 25°.
According to one embodiment, the lower locking surface is planar. According to an alternative embodiment, however, the lower locking surface may be curved. The curvature may be positive or negative, i.e. convex or concave, in a direction perpendicular to the vertical plane.
A shape of the lower locking surface may correspond to a shape of the upper locking surface—partly or entirely.
A tangent line TL to the lower locking surface may intersect the outer wall of the locking groove.
The upper locking surface may be located on the outer surface of the locking element. The lower locking surface may be located on the inner grove wall of the locking groove.
The upper locking surface may be spaced vertically upwards from an upper strip surface. The upper strip surface may be surface provided on the strip of the first short edge. The upper strip surface may be at least partially planar. Moreover, a portion of the upper strip surface may be curved. In a locked position, at least a portion of the upper strip surface may engage with a projection of the second short edge of the second panel. In particular, at least a portion of the upper strip surface may engage with the projection in a first edge section as well as in a second edge section.
According to a third aspect of the disclosure a set of essentially identical floor panels are provided with a mechanical locking system comprising a strip extending horizontally from a lower part of a first edge and a downwardly open locking groove formed in an adjacent second edge. The strip comprising an upwardly protruding locking element which is configured to cooperate with the locking groove for locking the first edge and the second edge in a horizontal direction parallel to a main plane of the panels and in a vertical direction perpendicularly to the horizontal direction. The locking element and the locking groove comprise an upper and a lower locking surface, which are configured to lock the panels vertically. The floor panels are characterized in that the upper locking surface is located on an upper part of the locking element facing an upper edge of the first panel, and that the upper locking surface is inclined or rounded and extends from the locking element and towards an inner part of the panel such that a tangent line to the upper locking surface of the locking element intersects the edge.
The upper part of the locking element may face the upper edge of the first panel. Moreover, the tangent line may intersect the first edge.
The tangent line may be specified in a cross-sectional side view of the panels. The tangent line may intersect the first edge at an upper part of the first edge.
In one non-limiting example, the upper locking surface is planar. In this case, the planar upper locking surface may be inclined with respect to a front side of the first panel by an angle between 0° and 45°, e.g. 20° or 25°. In another non-limiting example, the upper locking surface is rounded or, equivalently, curved. In this case, the curvature of the upper locking surface may be positive or negative, or put differently: the upper locking surface may be convex or concave in a direction perpendicular to the vertical plane. In case of a rounded upper locking surface, tangent lines at one or several points of the upper locking surface may intersect the first edge, as seen from a cross-sectional side view of the panels.
A shape of the upper locking surface may correspond to a shape of the lower locking surface—partly or entirely.
The locking system may be configured to be locked with a vertical displacement of the second edge against the first edge.
The locking system may be configured such that a vertical displacement of the second edge against the first edge during locking bends the strip downwards and turns the upper part of the locking element outwardly away from the upper edge.
The locking surfaces may be configured such that the upper and lower locking surfaces comprise upper and lower guiding surfaces that overlap each other during the downward bending of the strip.
According to a fourth aspect of the disclosure, there is provided a method for producing a locking system at edges of building panels. The building panels comprise a core and a locking surface formed in the core and extending essentially horizontally such that a tangent line to a part of the locking surface intersects an essentially vertical adjacent wall formed in the panel edge adjacent to the locking surface. The method comprises:
According to a fifth aspect of the disclosure, a set of essentially identical floor panels are provided with a mechanical locking system comprising a strip extending horizontally from a lower part of a first edge and a downwardly open locking groove formed in an adjacent second edge. The strip comprises an upwardly protruding locking element that is configured to cooperate with the locking groove and locks the first and the second edge in a horizontal direction parallel to a main plane of the first and the second panel and in a vertical direction perpendicularly to the horizontal direction. The locking system is configured to be locked with a vertical displacement of the second edge against the first edge, wherein an upper portion of the strip is configured to bend upwards towards the second panel.
Optionally, the upward bending of the strip may be combined with at least one of a twisting or a compression of the strip and/or the locking element.
The fifth aspect of the disclosure is largely analogous to the first aspect, except for the final stage of the vertical displacement downwards, wherein reference is made to the above embodiments and examples discussed in relation therewith.
Additionally, the locking element may assume the locked position by means of a smooth displacement upwards such that upper and lower locking surfaces may engage with each other in the locking position. Alternatively, it may snap into the locked position.
According to a sixth aspect of the disclosure, a set of essentially identical floor panels are provided with a mechanical locking system comprising a strip extending horizontally from a lower part of a first edge and a downwardly open locking groove formed in an adjacent second edge. The strip comprises an upwardly protruding locking element that is configured to cooperate with the locking groove and locks the first and the second edge in a horizontal direction parallel to a main plane of the first and the second panel and in a vertical direction perpendicularly to the horizontal direction. The locking system is configured to be locked with a vertical displacement of the second edge against the first edge, wherein a portion of the strip is configured to be displaced in a direction inwards by twisting and/or compressing the strip.
The sixth aspect of the disclosure is largely analogous to the first aspect, except that the upward and downward bending have been replaced by twisting and/or compression of the strip, wherein reference is made to the above embodiments and examples discussed in relation therewith. In particular, the portion of the strip may be a portion of the locking element, e.g. an upper portion of the locking element. Moreover, the upper portion of the locking element may be configured to be displaced during locking into a space provided between an outer groove wall of the locking groove and an inner surface of the locking element.
Additionally, the locking system may be further configured to be locked with a displacement of the portion of the strip in a direction outwards. For example, the strip may be untwisted and/or decompressed at least partly towards an initial unlocked position of the strip.
According to a seventh aspect of the disclosure, there is provided a set of essentially identical floor panels comprising a first panel and an adjacent second panel and being provided with a mechanical locking system comprising a strip extending horizontally from a lower part of a first edge of the first panel and a first downwardly open locking groove and a second downwardly open locking groove formed in a second edge of the second panel. The strip comprises a first upwardly protruding locking element and a second upwardly protruding locking element provided inwardly of the first locking element. Moreover, the second locking element is configured to cooperate with the second locking groove and to lock the first and the second edges in a horizontal direction perpendicular to a vertical plane defined by the joint adjacent first and second edges. The first locking element is configured to cooperate with the first locking groove and to lock the first and second edges in a vertical direction perpendicularly to said horizontal direction. The locking system is configured to be locked with a vertical displacement of the second edge against the first edge whereby an upper portion of the locking element is displaced into a space. The space is defined by a cavity between an outer groove wall of the first locking groove and an inner surface of the first locking element in a locked state of the panels.
According to one embodiment, the first and the second locking grooves are separated by a downwardly extending projection.
According to another embodiment, the first and the second locking groove are part of a common groove. The common groove may have an inner wall coinciding with a wall of the first locking groove and an outer wall coinciding with a wall of the second locking groove. Moreover, the common groove may have an intermediate wall connecting upper groove walls of the first and the second locking groove.
The seventh aspect of the disclosure is largely analogous to the first aspect, wherein reference is made to the above embodiments and examples discussed in relation therewith. In particular, it is understood that the upper portion of the locking element may optionally bend upwards, may be compressed and/or twisted, and may possibly also be bended downwards. Also, all the embodiments of the space according to the first aspect may be combined with the seventh aspect.
More generally, it is emphasized that the embodiments according to the various aspects of the disclosure may be combined in part or in their entirety with each other. Additionally, it is understood that in all of the above aspects the bending, twisting, compression, or deformation may be elastic or inelastic.
The disclosure will in the following be described in connection to exemplary embodiments and in greater detail with reference to the appended exemplary drawings, wherein:
As a comparison, bending of vertically protruding locking elements 8 are shown in
According to the present embodiment, the locking element 8 is essentially rigid and is not intended to be bended or compressed during locking that contrary to known technology is accomplished essentially with a horizontal displacement of the upper part of the locking element 8 towards the upper first edge 43. By essentially rigid is here meant that during locking the locking element itself is bended and/or compressed in a horizontal direction by a distance HD that is less than 50% of a horizontally protruding upper locking surface 11a located in the upper part of the locking element 8 as shown in
According to an alternative embodiment, the locking element 8 may be configured to bend during locking.
Adjacent edges comprise in locked position a first edge section 7a and a second edge section 7b. The edge sections are characterized in that a cross section of the locking groove 14 and/or a cross section of the locking element 8 varies along the adjacent edges of the panels 1, 1′ which are formed with a basic geometry that is thereafter modified such that the first 7a and the second 7b cooperating edge sections are formed with different geometries and different locking functions. Here, the geometries and cross sections are specified in a side view of the panels as shown in
The first edge section 7a is preferably a start section 30 that becomes active during a first initial step of the folding action and the second edge section 7b is preferably a subsequent section 31 or a middle section 31 that becomes active during a second step of the folding action.
It is clear that, according to an alternative embodiment, the second edge section 7b may be a start section 30 that becomes active during a first initial step of the folding action and that the first edge section 7a may be a subsequent section 31 or a middle section 31 that becomes active during a second step of the folding action. This is shown in
The first 12a and the second 12b locking surfaces may be inclined against the vertical plane VP. Such geometry may be used to facilitate unlocking of the short edges with an angling action. A locking system with vertical first 12a and second 12b locking surfaces may be unlocked with a sliding action along the short edges.
According to the present embodiment, the space S has a vertical extension substantially corresponding to a vertical extension of the inner surface 8a so that it extends down to the upper strip surface 6a. It is clear that, according to alternative embodiments (not shown), the space S may have a smaller vertical extension. Preferably, however, the space S is located at an upper part of the locking element 8. Moreover, the vertical extension is preferably larger than a vertical extension of an upper protruding part 25 formed on an outer and upper part of the locking element 8, e.g. 1.5, 2 or 3 times larger.
In a first example, the vertical extension of the space S varies along the edge. The vertical extension may vary along the edge from a minimal vertical extension to a maximal vertical extension and then, optionally, back to a minimal vertical extension. The variation may be smooth.
In a second example, the vertical extension of the space S is constant along the edge. A first and a second wall of the space S that are spaced from each other along the edge may be vertical and parallel.
By way of example, the space S may be formed by means of milling, scraping, punching, perforation or cutting.
The strip 6 and the locking element 8 are during locking twisted along the first short edge. In the first edge section 7a, the strip 6 is essentially in a flat horizontal position during locking and in the second edge section 7b the strip 6 is bended upwards and the locking element 8 with its upper locking surface is turned and/or displaced inwardly during locking.
Optionally, or alternatively, at least portions of the strip 6 may be twisted and/or compressed during locking. For example, a portion between a lower part of the strip 6b and the upper strip surface 6a and/or the locking element 8 of the strip 6 may be twisted and/or compressed. The twisting may occur at least around an axis that is perpendicular to the vertical plane VP. The compression may occur at least inwardly in a horizontal direction that is perpendicular to the vertical plane VP. In particular, the strip 6 may be twisted in the transition regions between the first 7a and second 7b edge sections. Moreover, the strip 6 may become compressed in the second edge section 7b and such compression may facilitate a displacement of the locking element 8 even in rather rigid materials since the material content of the strip 6 is much larger than the material content of the locking element 8. As an example it may be mentioned that the locking element 8 may have a horizontal extension of about 4 mm and the strip 6 may protrude horizontally about 8 mm from the side wall 45 and to the inner surface 8a of the locking element. At a compression of 1%, the locking element will contribute with 0.04 mm or with about ⅓ of a total compression and the strip with 0.08 mm or with about ⅔ of the total compression. Generally, the locking element in an HDF based laminate floor must be displaced horizontally with a distance of at least 0.2 mm in order to provide sufficient locking strength. 0.4 mm is even more preferred. Depending on the joint geometry and material properties about ⅓ of the necessary displacement may be accomplished with material compression and ⅔ with bending and turning or twisting of the strip and the locking element.
The upper 11a and lower 11b locking surfaces are preferably essentially horizontal. The locking surfaces are in the showed embodiment inclined against a horizontal plane HP with a locking angle LA that is about 20 degrees. The locking angle LA is preferably 0-45 degrees. Locking surfaces with low locking angles are preferred since they provide a stronger vertical locking. The most preferred locking angle LA is about 5-25 degrees. However it is possible to reach sufficient locking strength in some applications with locking angles between 45 and 60 degrees. Even higher locking angles may be used but such geometries will decrease the locking strengths considerably.
According to the present embodiment, there is an intermediate cavity 47 provided between a portion of the upper support surface 16 and a portion of the upper strip surface 6a. Since a thickness of the strip 6 in this area is smaller than at the location of the lower support surface 15, the strip may be bended more easily. The upper support surface 16 preferably is a planar surface and the projection 50 preferably has a constant thickness in a direction perpendicular to the vertical plane VP as measured from its surface layer 2. The thickness is preferably also constant along the edge of the second panel 1′.
According to an alternative embodiment (not shown), however, the thickness of the projection 50 may vary in a direction perpendicular to the vertical plane VP. Thereby, least a portion of the projection 46 may extend below the lower support surface 15.
The space S is an essential feature in this embodiment of the disclosure. A horizontal extension of the space S along a horizontal plane HP that intersects the upper 11a and lower 11b locking surfaces preferably exceeds a horizontal distance HD of the upper and lower locking surfaces. Here, the horizontal extension of the space S may be a maximal horizontal extension.
According to the present embodiment, the space S has a vertical extension substantially corresponding to a vertical extension of the outer groove wall 14a so that it extends up to the upper groove wall 14c. It is clear that, according to alternative embodiments (not shown), the space S may have a smaller vertical extension. Preferably, however, the space S is located adjacent to the upper groove wall 14c. Moreover, the vertical extension is preferably larger than a vertical extension of the upper protruding part 25, e.g. 1.5, 2 or 3 times larger.
The vertical extension of the space S may vary or may be constant along the edge as explained above in relation to the embodiment in
It is stressed that any of the additional and/or optional features described above in relation to the embodiments in
In any of the embodiments in the present disclosure, there may also be an upper cavity 48 between the upper groove wall 14c and the upper surface 8c in a locked position of the first 1 and second 1′ panel. The upper cavity 48 may be located in the second edge second 7b and optionally also in the first edge section 7a. Thereby, there is more space provided in the second edge section 7b for the upwardly bending locking element 8.
Additionally, it is clear that there may be at least one first edge section 7a and at least one second edge section 7b. In particular, there may be a plurality of first 7a and second 7b edge sections along the edge. The first 7a and second 7b edge sections may be arranged alternately. In particular, the edge sections may be arranged in a sequence along the edges such as {7a, 7b, 7a}, {7a, 7b, 7a, 7b, 7a} or {7a, 7b, 7a, 7b, 7a, 7b, 7a} with a first edge section 7a at the corners of the edges. Alternatively, there may be a second edge section 7b at the corners of the edges so that a sequence such as {7b, 7a, 7b}, {7b, 7a, 7b, 7a, 7b} or {7b, 7a, 7b, 7a, 7b, 7a, 7b} is provided along the edges.
The pressure against the locking element 8 will create separation forces tending to displace the second panel 1′ horizontally away from the first panel 1, but that are counteracted by the first and the second locking surfaces 12a, 12b of the first edge section 7a. The pressure that is needed to lock the edges may be reduced if the sliding surface 27 is essentially vertical and extends over a substantial vertical sliding distance SD, measured vertically over a distance where the inner groove wall 14b is in contact with the outer surface 8b of the locking element during the vertical displacement, and/or if the vertical extension VE of the locking element 8, defined as the vertical distance from the lowest point on the upper surface of the strip 6a and to the upper surface 8c of the locking element 8, is large. Preferably, the inclination of the sliding surface 27 is 10-30 degrees in relation to a vertical plane VP and the vertical sliding distance SD is 0.2-0.6 times the size of floor thickness T. A vertical sliding distance SD of 0.3-0.5 times the size of floor thickness T is even more preferred. Preferably, the vertical extension VE of the locking element 8 is 0.1-0.6 times the size of floor thickness T. 0.2*T-0.5*T is even more preferred.
An upward bending of a strip is suitable for wood based cores, such as for example HDF, since the fibres in the upper part of the strip that are sensitive to pulling forces and shear stress will be compressed and the fibres in the lower and stronger part of the strip that are more resistant to pulling forces and shear stress will be stretched. A considerable amount of bending deflection 29 may be reached and a strip 6 that extends horizontally from the upper edge about 8 mm or with the same distance as the floor thickness T may be bended upwards about 0.05-1.0 mm, e.g. 0.1 mm or 0.5 mm. Here, a bending deflection 29 is defined as a vertical distance, in a direction perpendicular to the horizontal plane HP, from a horizontal plane HR being parallel and essentially coinciding with the rear side 60 of the first panel 1 in an unlocked state to an outermost and lowermost part of the strip 6. Thus, the bending deflection 29 typically varies along the edge of the first panel 1 and also varies during the various stages of the locking. A maximal bending deflection 29 may be located in a middle portion of a second edge section 7b along a length direction of the edges.
Another advantage is that problems related to thickness tolerances of the panels may be avoided since even in the case that the second panel 1′ is thicker than the first panel 1 and normally will hit the sub floor 35 before the upper surfaces are in the same horizontal plane, locking may be made with offset upper edges where the surface of the second edge is above the first edge and the strip will pull the panels to a correct position with horizontally aligned upper surfaces and upper and lower support surfaces 15, 16 in contact with each other. Such locking function is also favorable when the floor panels are installed on a soft underlay, such as foam, and a counter-pressure from the sub floor cannot be used to prevent a downward bending of the strip 6.
A strip formed in soft materials such as an LVT core comprising thermoplastic materials and filler may not snap back towards the initial position after the locking. This may be solved with a joint geometry where the upper groove wall 14c is formed to be in contact with the upper surface 8c of the locking element 8 during the final stage of the locking action such that the locking element 8 and the strip 6 are pressed downwards. The locking system may also be formed with an outer and lower support surface 15a that cooperates with the projection 46 during locking in order to press the strip 6 downward to or towards its initial position as shown in
This production technology may be used to form the first 7a and the second 7b edge sections.
A vertical extension of the second locking element 8′ and/or the second locking groove 14′ may vary along the first and/or second edge, respectively. The vertical extension may vary from a maximal extension to a minimal extension. The variation may be periodic. At the maximal extension, a top surface of the second locking element 8′ may engage with an upper groove wall of the second locking groove 14′. At the minimal extension, there may be a cavity between the top surface of the second locking element 8′ and the upper groove wall of the second locking groove 14′.
A vertical flex groove 39 may be formed adjacent to and preferably inwardly of the locking groove 14 in all embodiments of the disclosure.
This embodiment offers the advantages that continuous grooves and locking elements without any edge sections may be used and this will simplify the forming of the locking system. A locking system with high vertical and horizontal locking strength may be formed. The space S between the first locking element 8 and the first locking groove 14 allows a turning and/or displacement of the locking element 8 as described in the previous embodiments. The horizontal distance D1 between the inner surfaces 8a of the first locking element 8 and the outer surface 8b ′ of the second 8′ locking element is preferably at least about 30% the floor thickness FT in order to provide sufficient flexibility and locking strength. The horizontal distance D1 may be as small as about 20% of the floor thickness. More generally, D1 may be between 20% and 80% of FT. An upper part of the first locking element 8 is preferably located closer to the panel surface than an upper part of the second locking element 8′. Alternatively, however, the upper part of the first locking element 8 may be located closer to the panel surface than the upper part of the second locking element 8′. This may reduce separation forces since the second locking element 8′ will become active before the first element 8 is in contact with the locking groove 14.
The flex groove 39 may also extend along a part of the edge of the second panel 1′. In the embodiment in
Generally, it is noted that each wall of the flex groove may be vertical or, alternatively, have a transition region so that a depth of the flex groove increases along the edge from a minimal depth to a maximal depth.
Moreover, there may be two or more flex grooves 39 arranged along the edge. In the embodiment in
Preferably, the flex groove 39 does not extend entirely through the second panel 1′. By way of example, the flex groove 39 may have a vertical extension between 30% and 60% of a maximal thickness of the panel, e.g. 40% or 50%.
As shown in the top views of the first panel 1 in
In the embodiment in
Generally, it is noted that each wall of the slits may be vertical, i.e. parallel with a direction perpendicular to the horizontal plane. For example, in the embodiment in
Such embodiments may be used in floor panels with flexible core materials, for example a core comprising thermosetting plastic material, but may also be used in other applications. As already noted, the locking system may be formed according to any previous embodiment of the disclosure. A horizontal extension of the locking element 8 may be larger than a horizontal extension of the upper surface of the strip 6a. Outer parts of the locking element 8 may have a smaller vertical extension than inner parts of the locking element for increasing the flexibility of the locking element. The major difference as compared to the embodiments disclosed above is that no space S is needed since the locking element 8 may be bended upwards and/or compressed inwardly as shown in
The first edge section 7a′ in
| Number | Date | Country | Kind |
|---|---|---|---|
| 1451632-2 | Dec 2014 | SE | national |
The present application is a continuation of U.S. application Ser. No. 16/204,185, filed on Nov. 29, 2018, which is a continuation of U.S. application Ser. No. 15/726,754, filed on Oct. 6, 2017, now U.S. Pat. No. 10,161,139, which is a divisional of U.S. application Ser. No. 14/973,179, filed on Dec. 17, 2015, now U.S. Pat. No. 9,803,374, which claims the benefit of Swedish Application No. 1451632-2, filed on Dec. 22, 2014. The entire contents of U.S. application Ser. No. 16/204,185, U.S. application Ser. No. 15/726,754, U.S. application Ser. No. 14/973,179 and Swedish Application No. 1451632-2 are hereby incorporated herein by reference in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14973179 | Dec 2015 | US |
| Child | 15726754 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 16204185 | Nov 2018 | US |
| Child | 16745613 | US | |
| Parent | 15726754 | Oct 2017 | US |
| Child | 16204185 | US |
