Abstract
A floor covering has a decorative surface lying in a plane of the floor covering and includes rectangular floor panels, with each floor panel having: a core and a decorative layer on the core. At least a first pair of opposite edges is provided with mechanical coupling means so a plurality of similar panels can be coupled to one another. The coupling means provides for an interlocking in a direction perpendicular to the plane of the floor covering, and a direction perpendicular to the coupled edges and parallel to the plane of the floor covering. The floor covering includes a plurality of alignment elements with each edge of the floor panel and at least partially defining a hollow receiving cavity below the decorative layer and having a shape such that, when a first edge of a second floor panel is coupled to a second edge of a first floor panel.
Claims
1.-18. (canceled)
19. A floor covering having a decorative surface lying in a plane of the floor covering, said floor covering comprising rectangular floor panels, each floor panel having: a core, a first edge and a second edge forming a first pair of opposite edges, a third edge and a fourth edge forming a second pair of opposite edges, and four corners at intersections of said edges, at least said first pair of opposite edges being provided with mechanical coupling means so that a plurality of said floor panels can be coupled to one another, said coupling means providing for an interlocking in a direction perpendicular to the plane of the floor covering, as well as in a direction perpendicular to the coupled edges and parallel to the plane of the floor covering, said floor covering further comprising a plurality of alignment elements, wherein each edge of said floor panels at least partially defines a hollow receiving cavity below said decorative layer, the hollow receiving cavity having a shape such that when a first edge of a second floor panel is coupled to a second edge of a first floor panel, said hollow receiving cavities are aligned to form a receiving pocket within which one of said plurality of alignment elements is at least partially received.
20. The floor covering according to claim 19, wherein said hollow receiving cavity is provided at each corner of said floor panels, said hollow receiving cavity extending from the intersection of the two edges forming the corner and part way along each of the two edges.
21. The floor covering according to claim 19, wherein said floor panels are laid to form a chessboard pattern, with no offset edges.
22. The floor covering according to claim 21, wherein said hollow receiving cavity is provided at each corner of said floor panels, said hollow receiving cavity extending from the intersection of the two edges forming the corner and part way along each of the two edges and wherein at a meeting point of four floor panels, a substantially closed receiving compartment is formed by the hollow receiving cavities of the corners of the meeting point, said substantially closed receiving compartment accommodating one of said plurality of alignment elements.
23. The floor covering according to claim 22, wherein each hollow receiving cavity is essentially right-triangular shaped such that said substantially closed receiving compartment is essentially square-shaped.
24. The floor covering according to claim 22, wherein each hollow receiving cavity is essentially right-triangular shaped such that said closed receiving compartment is essentially lozenge-shaped, said lozenge shape having a major diagonal and a minor diagonal, the major diagonal having a length which is at least 20% greater than the length of the minor diagonal.
25. The floor covering according to claim 24, wherein the length of the major diagonal is between three and four times greater than the length of the minor diagonal.
26. The floor covering according to claim 24, wherein each essentially right-triangular shaped hollow receiving cavity has a hypotenuse which is curved.
27. The floor covering according to claim 19, wherein each said hollow receiving cavity is located along each edge, midway along each edge.
28. The floor covering according to claim 19, wherein each of said plurality of alignment elements has a shape corresponding substantially to that of the receiving pocket or substantially closed receiving compartment.
29. The floor covering according to claim 19, wherein each of said plurality of alignment elements has a substantially planar profile having a thickness.
30. The floor covering according to claim 19, wherein each of said plurality of alignment elements is made of a plastic material.
31. The floor covering according to claim 19, wherein said receiving pocket and/or said substantially closed receiving compartment has a depth in a direction perpendicular to the plane of the floor covering, said depth being greater than, or substantially equal to, a thickness of said plurality of alignment elements.
32. The floor covering according to claim 19, wherein the mechanical locking means are constituted by a tongue and a cooperating groove delimited by an upper lip and a lower lip, wherein said tongue and groove comprise locking elements which prevent the tongue and groove from moving apart in a coupled condition, wherein said locking elements comprise an upwardly directed locking element on the lower lip and a downwardly directed locking element on the tongue cooperating with said upwardly directed locking element and wherein, in a coupled condition, a contact surface is formed between the top of the tongue and the bottom of the upper lip, wherein said receiving pocket and/or said substantially closed receiving compartment has a depth in a direction perpendicular to the plane of the floor covering, said depth being greater than, or substantially equal to, the thickness of the tongue, being the dimension of the tongue in a direction perpendicular to the plane of the floor panel from the contact surface to the lowest point of the downwardly directed locking element of the tongue and wherein the top of said receiving pocket and/or said substantially closed receiving compartment extends at the height of said contact surface.
33. The floor covering according to claim 19, wherein the thickness of the part of the panel situated above the the receiving pocket and/or said substantially closed receiving compartment, being the dimension in a direction perpendicular to the plane of the floor covering, between the top of the panel and the receiving pocket and/or said substantially closed receiving compartment, is at least 1.2 mm.
34. The floor covering according to claim 32, wherein the thickness of the part of the panel situated above the the receiving pocket and/or said substantially closed receiving compartment, being the dimension in a direction perpendicular to the plane of the floor covering, between the top of the panel and the receiving pocket and/or said substantially closed receiving compartment, is at least 1.2 mm and wherein the part of the panel situated above the the receiving pocket and/or said substantially closed receiving compartment, is the part of the panel situated above the tongue and wherein said part has an equal thickness as the biggest thickness of the upper lip of the groove.
35. The floor covering according to claim 19, wherein said mechanical coupling means allow said floor panels to be coupled to one another via a snap action.
36. The floor covering according to claim 35, wherein said snap action occurs as two floor panels are shifted towards each other in a direction substantially parallel to the plane of the floor covering and/or said snap action occurs as two floor panels are shifted towards each other in a direction substantially perpendicular to the plane of the floor covering.
37. The floor covering according to claim 19, wherein a decorative layer is provided on said core, said decorative layer forming a portion of said decorative surface.
38. The floor covering according to claim 23, wherein each essentially right-triangular shaped hollow receiving cavity has a hypotenuse which is curved.
Description
[0053] The invention will be described below in greater detail, by way of example only and with reference to the accompanying drawings, in which:
[0054] FIGS. 1A and 1B schematically and in perspective each represent a portion of a floorcovering in accordance with the present invention;
[0055] FIG. 2 is a schematic plan view of one of the floor panels making up the floor covering of FIG. 1A;
[0056] FIG. 3 is an elevational view in the direction of arrow F3 in FIG. 2;
[0057] FIG. 4 is an elevational view in the direction of arrow F4 in FIG. 2;
[0058] FIG. 5 is a schematic perspective view of a floor panel making up a portion of the floor covering according to FIG. 1A;
[0059] FIG. 6 is a schematic perspective view on a larger scale of a portion of the floor panel of FIG. 5 marked as F6;
[0060] FIG. 7 illustrates a receiving pocket for an alignment element;
[0061] FIGS. 8 to 11 illustrate how four floor panels can be laid to form a floor covering according to the present invention;
[0062] FIG. 12 is a plan view of a lozenge-shaped alignment element according to one embodiment of the present invention;
[0063] FIG. 13 is a schematic plan view of four floor panels of the floor covering having a common meeting point;
[0064] FIG. 14 is a plane view of another embodiment of an alignment element for use in the floor covering of the present invention;
[0065] FIGS. 15 to 19 schematically illustrate how floor panels for use in the floor covering of the present invention may be made;
[0066] FIG. 20 is a plan view of a floor panel having an alternative arrangement of hollow receiving cavities;
[0067] FIG. 21 schematically illustrates a receiving pocket which is created when two floor panels of FIG. 20 are coupled together;
[0068] FIG. 22 in a view similar to that of FIG. 2 or 20, albeit at smaller scale, shows a floor panel for another embodiment of the present invention;
[0069] FIG. 23 illustrates a potential installation orientation of the floor panels of FIG. 22;
[0070] FIG. 24, in a view similar to that of FIG. 22, shows a floor panel for still another embodiment of the present invention;
[0071] FIG. 25 illustrates a potential installation orientation of the floor panels of FIG. 24;
[0072] FIG. 26, in a top view, shows floor panels for still another embodiment of the present invention;
[0073] FIG. 27, shows a view in accordance with the arrow F27 in FIG. 26; and
[0074] FIG. 28 shows a perspective view of the alignment element that may be used in connection to the floor panels of FIGS. 26 and 27;
[0075] FIGS. 29 to 32 are plane views of possible embodiments of an alignment element for use in the floor covering of the present invention;
[0076] FIG. 33 is a view similar to a detail of FIG. 3 at the height of the tongue, showing a variant wherein the receiving cavity has a depth smaller than the thickness of the tongue;
[0077] FIG. 34 is a detail of FIG. 3 at the height of the tongue, showing that the receiving cavity has a depth that equals the thickness of the tongue;
[0078] FIG. 35 is a view similar to a detail of FIG. 3 at the height of the tongue, showing a variant wherein the tongue is present at a lower position than in FIG. 34;
[0079] FIG. 36 is a detail of FIG. 3 at the height of the groove.
[0080] In the drawings, reference number 10 denotes a floor covering in accordance with the present invention. As may be gleaned from FIGS. 1A and 1B, the floor covering 10 comprises rectangular floor panels 12. In FIG. 1A, the floor panels 12 are square, whereas in FIG. 1B the floor panels are oblong. The floor covering has a decorative surface 14 lying in a plane of the floor covering.
[0081] With reference to FIG. 2, each floor panel 12 has a first edge 16 and a second edge 18 forming a first pair of opposite edges, and a third edge 20 and a fourth edge 22 forming a second pair of opposite edges. Thus, the floor panel 12 has four corners 23 at intersections of the edges. In FIG. 2 the floor panel is square, though it is to be understood that, for an oblong floor panel having a pair of short edges and a pair of long edges, the first pair of opposite edges is preferably constituted by the pair of short edges. In this manner, and as is illustrated in FIG. 1B, a row of oblong floor panels is formed by coupling the floor panels together at their short edges 16, 18. In a corresponding manner, a row of square floor panels 12, as illustrated in FIG. 1A, is formed by coupling the floor panels together at their first pair of opposite edges 16, 18.
[0082] To allow floor panels 12 to be coupled together, at least the first pair of opposite edges 16, 18, though preferably both pairs of opposite edges, are provided with mechanical coupling means 24. The mechanical coupling means 24 can have various forms as long as they provide for an interlocking in a vertical direction V perpendicular to the plane of the floor covering, as well as in a horizontal direction H perpendicular to the coupled edges and parallel to the plane of the floor covering. The directions V and H are shown in FIGS. 1A and 1B. One form of coupling parts which may be employed on the first pair of edges 16, 18 is shown in FIG. 3. FIG. 3 is an elevational view shown in the direction of arrow F3 in FIG. 2, i.e. a view of the fourth edge 22. The mechanical coupling means 24 are constituted by a tongue 26 at the first edge 16 and a cooperating groove 28 at the second edge 18. In a manner described in more detail in WO 97/47834, the groove 28 is delimited by an upper lip 30 and a lower lip 32. To aid in the guiding of the tongue 26 into the groove 28 of an adjacent floor panel, the lower lip 32 of the groove may be made longer than the upper lip 30. The lower lip 32 is provided with a recess 34 into which a protrusion 36 on a lower surface of the tongue 26 fits when two panels are coupled together. Floor panels with such mechanical coupling means can be joined together by way of an angling down motion in which the tongue 26 on the first edge 16 of one floor panel, after having been inserted at an inclined angle into the groove 28 on the second edge 18 of an already laid floor panel, is angled downwards until the protrusion 36 on the tongue 26 fits into the recess 34 in the lower lip of the groove 28. During the angling down motion, the coupling means 24 may undergo an elastic deformation so that the protrusion 36 snaps into the recess 34. Preferably, the same mechanical coupling means also allow for two panels to be joined by means of a relative horizontal motion.
[0083] In one embodiment, and as is illustrated in FIG. 4, mechanical locking means 24 may also be provided at the second pair of opposite sides 20, 22. Thus, FIG. 4 is an elevational view in the direction of arrow F4 in FIG. 2, i.e. a view of the second edge 18. The mechanical coupling means 24 are constituted by a tongue 26 at the third edge 20 and a cooperating groove 28 at the fourth edge 22. The tongue 26 and the groove 28 at the second pair of opposite sides may have similar profiles to the coupling means on the first pair of opposite sides, meaning that two adjacent floor panels may be joined together by an angling down motion and/or a horizontal motion.
[0084] It is to be understood that the mechanical coupling means 24 may be of any type that will permit a plurality of floor panels 12 to be coupled to one another in the horizontal and vertical directions without the need for adhesive. Purely by way of example, useful such mechanical coupling means are described in WO 2021/111210 and WO 2010/082171. Preferably, the mechanical coupling means extend over a majority of the length of the edges on which they are located.
[0085] Referring to FIGS. 5 and 6, each floor panel 12 has a core 38 and a decorative layer 40 on the core. The decorative layer may be constituted by a separate sheet or foil laminated to the core, or it may be a decoration that is printed and/or embossed directly onto the core. As indicated by reference number 42, at each corner 23 of the floor panel there is a hollow receiving cavity below the decorative layer 40. The hollow receiving cavity 42 has an internal wall 44 which extends between adjacent edges of the floor panel such that each edge at least partially defines the hollow receiving cavity 42. Consequently, the hollow receiving cavity extends from the intersection of the two edges forming the respective corner 23 and part way along each of the two edges. The hollow receiving cavity 42 is adapted to partially receive an alignment element 46. As is apparent from FIG. 6, the hollow receiving cavity accommodates approximately a quarter of the alignment element 46. The alignment element 46 has a thickness t.sub.c which is, in the example, about equal to the depth d of the hollow receiving cavity 42.
[0086] FIG. 7 illustrates a first floor panel A and a second floor panel B of a row of floor panels. The second edge 18 of the first floor panel A is coupled to the first edge 16 of the second floor panel B. The hollow receiving cavity 42 of each floor panel has a shape such that, when the two panels are coupled together, the hollow receiving cavities are aligned to form a receiving pocket 48. The receiving pocket 48 partially receives the alignment element 46. When inserted in the receiving pocket 48, the alignment element 46 provides a visual indication as to whether the two floor panels are properly aligned with each other.
[0087] As will be described in the following with reference to FIGS. 8 to 11, the alignment element 46 can aid in the alignment of floor panels during laying and may aid in the maintenance of the panels in an aligned condition.
[0088] Thus, FIGS. 8 to 11 schematically illustrate how a floor covering according to the present invention may be laid using alignment elements 46. In common with FIG. 7, FIG. 8 illustrates a first floor panel A and a second floor panel B of a first row of floor panels, with the second edge 18 of the first floor panel A being coupled to the first edge 16 of the second floor panel B. FIG. 8 also illustrates a third floor panel C and a fourth floor panel D which are to form floor panels of an adjacent row. Once the first floor panel A and the second floor panel B are coupled together, a receiving pocket 48 is formed having an insertion opening along a common edge of the row of floor panels to which the third floor panel C and the fourth floor panel D are to be coupled. For ease of laying, this common edge is preferably made up of the respective fourth edges 22 of the first and second floor panels. The first row of floor panels may be extended by coupling further (not illustrated) floor panels to the second edge 18 of the second floor panel B.
[0089] When it is desired to lay an adjacent row of floor panels, and as is illustrated in FIG. 9, an alignment element 46 is inserted into the receiving pocket 48 between the first and second floor panels. Since the receiving pocket 48 only partially receives the alignment element 46, a protruding portion 50 of the alignment element extends beyond the common fourth edge 22 of the first row of floor panels. The protruding portion 50 is then used to ensure correct alignment of the third and fourth floor panels C, D. Accordingly, and as is apparent from FIG. 10, the third edge 20 of the third floor panel C is coupled to the fourth edge 22 of the first floor panel A so that approximately half of the protruding portion 50 of the alignment element 46 is received in the hollow receiving cavity 42 at the intersection between the second edge 18 and the third edge 20 of the third floor panel C. The coupling of the third edge 20 of the third floor panel C to the fourth edge 22 of the first floor panel A is preferably attained by displacing the third floor panel horizontally towards the first floor panel so that the mechanical coupling means along the adjacent edges snap into each other.
[0090] Finally, and as is shown in FIG. 11, a fourth floor panel D is coupled to the third floor panel C and the second floor panel B. Depending on the type of mechanical coupling means at the first and second pair of opposite edges, it may be advantageous to couple the first edge 16 of the fourth floor panel D to the second edge 18 of the third floor panel C such that the third edge 20 of the fourth floor panel D is initially spaced from the fourth edge 22 of the second floor panel B. Thereafter, the fourth floor panel D may be displaced in a horizontal direction towards the second floor panel B by sliding the fourth floor panel D along the made-up joint between it and the third floor panel C until the protruding portion 50 of the alignment element 46 enters the hollow receiving cavity 42 in the fourth floor panel D. The sliding motion of the fourth floor panel D may be followed by an angling up and down to ease the coupling of the fourth floor panel D with the second floor panel B. Preferably, in such case, the alignment element 46 is somewhat flexible and/or, for example, has a major diagonal 56 that is at least 5 times its thickness t.sub.c. Once the fourth floor panel D has been coupled to the second floor panel B, a meeting point 52 of the first to fourth floor panels is created. At the meeting point, a substantially closed receiving compartment 54 is formed by the hollow receiving cavities 42 of the corners 23 of the meeting point 52. The substantially closed receiving compartment 54 thereby accommodates the alignment element 46.
[0091] The substantially closed receiving compartment 54 will have a shape which is dictated by the shape of the hollow receiving cavities 42. In the FIGS. 2 to 11 embodiments, each hollow receiving cavity 42 is essentially right-triangular shaped, with the hollow receiving cavity having a greater extension along the first pair of edges 16, 18 than the second pair of edges 20, 22. The difference in extension of the hollow receiving cavities 42 along the edges can be clearly seen when comparing FIG. 3 with FIG. 4. The substantially closed receiving compartment 54 which is formed at the meeting point 52 of four of the floor panels will then be essentially lozenge-shaped. Advantageously, each of the alignment elements 42 has a shape corresponding substantially to that of the substantially closed receiving compartment 54. Thus, FIG. 12 illustrates an alignment element 46 having substantially the same lozenge shape as that of the closed receiving compartment. The lozenge shape has a major diagonal 56 and a minor diagonal 58, with the major diagonal having a length which is at least 20% greater than the length of the minor diagonal. In order to more securely retain the alignment element 46 in the receiving pocket 48 between the first floor panel A and the second floor panel B as the floor covering is being laid (see FIG. 9), the length of the major diagonal 56 may be considerably greater than that of the minor diagonal 58. For example, the major diagonal 56 may have a length which is at least 50% greater, optionally at least 100% greater or at least 200% greater, than the length of the minor diagonal 58. In a particular embodiment, the length of the major diagonal 56 may be between three and four times greater than the length of the minor diagonal. FIGS. 29 to 32 show possible variants of the alignment element 46. FIG. 29 shows an alignment element 46 having substantially the same lozenge shape as that of the closed receiving compartment, but with truncated corners 79. FIGS. 30 to 32 show alignment elements 46 having substantially the same lozenge shape as that of the closed receiving compartment and which comprise cut-outs 80 and/or truncated corners 79. FIG. 32 shows an alignment element 46 having substantially the same lozenge shape as that of the closed receiving compartment and having snapping hooks 81, truncated corners 79 and cut-outs 80.
[0092] In the embodiment illustrated in FIG. 13, each hollow receiving cavity 42 is essentially right-triangular shaped, with the internal wall 44 of the hollow receiving cavity subtending an angle of about 45 to the adjacent edges of the floor panel 12. This results in the substantially closed receiving compartment 54 being essentially square-shaped. Consequently, and as shown in FIG. 14, each of the alignment elements 46 will, preferably, also be essentially square-shaped. An embodiment having a receiving compartment 54 with four equal quadrants, as is the case in FIG. 13, allows to match any corner of one panel 12 with any corner of another panel while always obtaining a receiving compartment 54 having a same geometry. Such an embodiment may allow installing panels 12 with alternating orientation, i.e. alternatingly coupling first and fourth edges, with coupling third and second edges to form a row. This of course requires the coupling means at first and second edges to be compatible with the coupling means at respectively fourth and third edges. Preferably, the coupling means at both pairs of edges have an identical, or largely identical geometry.
[0093] The shape of the hollow receiving cavities 42 is influenced by how the floor panels 12 are produced. FIGS. 15 to 19 illustrate part of a continuous process for milling the edges 16, 18, 20, 22 of a floor panel 12 and forming a hollow receiving cavity 42 at each of the corners. In FIG. 15, reference number 60 generally denotes a first end-tenoner which is set up to mill a second pair of opposite edges 20, 22 of a floor panel 12. Although the drawings illustrate a square floor panel, it is to be understood that if the floor panel is oblong, the first end-tenoner will preferably mill the long sides of the floor panel. As the floor panel 12 is moved in a first direction 62, the first end-tenoner 60 mills the second pair of opposite edges 20, 22 to provide them with complementary mechanical coupling means 24, for example as shown in FIG. 4. Thus, the third edge 20 may be provided with a tongue 26, whereas the fourth edge 22 may be provided with a groove 28. Upon exiting the first end-tenoner 60, the floor panel 12 is, in the example, temporarily held in a buffer stock, and then caused to move in a second direction 64 perpendicular to the first direction 62 towards a second end-tenoner 66. The floor panel is driven in the second direction 64 by means of cams 68 acting on the already machined fourth edge 22 of the floor panel. Since the fourth edge has been machined, accurate alignment of the floor panel when passing through the second end-tenoner 66 is assured.
[0094] Turning to FIG. 16, as the floor panel 12 is moved in the second direction 64, the second end-tenoner 66 mills the first pair of opposite edges 16, 18 to provide them with complementary mechanical coupling means 24, for example as shown in FIG. 3. Thus, the first edge 16 may be provided with a tongue 26, whereas the second edge 18 may be provided with a groove 28. When milling oblong floor panels, the second end-tenoner 66 will preferably mill the short sides. Since the production process is continuous, the short sides may be milled in the same time that it takes to mill the long sides of an upstream panel. Accordingly, the short sides can be milled at a lower speed, thereby enhancing accuracy.
[0095] In the second end-tenoner 66, preferably at the downstream end of the second end-tenoner 66, a pair of jumper tools 70 is provided. The jumper tools 70 can be moved towards and away from each other in a direction perpendicular to the second direction 64 of movement of the floor panel 12. As the floor panel approaches the pair of jumper tools 70, the jumper tools are positioned towards each other in an engagement position. When the floor panel 12 reaches the pair of jumper tools 70, and as is shown in FIG. 17, the jumper tools 70 initially contact the leading edge of the floor panel, namely the third edge 20. As the floor panel proceeds past the pair of jumper tools, the jumper tools are retracted (FIG. 18) and exit the floor panel along the first pair of opposite edges 16, 18 to thereby form a hollow receiving cavity 42 at each corner between the third edge 20 and the first and second edges 16, 18, respectively. By controlling the speed of retraction of the jumper tools with respect to the speed of movement of the floor panel past the pair of jumper tools, the size and shape of the hollow receiving cavities 42 can be determined.
[0096] To form hollow receiving cavities 42 at the corners of the trailing edge, i.e. the fourth edge 22, and as is shown in FIG. 19, the pair of jumper tools 70 is controlled such that the jumper tools 70 are brought into contact with the first pair of edges 16, 18 and moved towards their engagement position. The jumper tools 70 then exit the floor panel 12 along the fourth edge 22. The pair of jumper tools is then kept in its engagement position until an immediately upstream floor panel reaches the pair of jumper tools to, preferably perform a same or similar sequence of movements as described above for machining the edges of the upstream panel.
[0097] The above-described movement of the pair of jumper tools 70 can provide hollow receiving cavities 42 with an internal wall 44 that is curved, as shown for example in FIG. 6. Since each hollow receiving cavity is essentially right-angular shaped, the curved internal wall 44 forms the hypotenuse of the right-angular shape. Accordingly, each edge of the alignment element 46 may have a correspondingly curved shape.
[0098] Each jumper tool 70 has a circular saw blade 72 having a blade thickness to, as indicated on FIG. 3. The saw blade 72 cuts a slot into the core 38 of the floor panel, which slot forms a hollow receiving cavity 42. The blade thickness to will determine the depth d of the hollow receiving cavities 42 in a direction perpendicular to the plane of the floor covering. The depth d is shown in FIGS. 3 and 4. When several floor panels are coupled together, aligned hollow receiving cavities will form receiving pockets 48 and substantially closed receiving compartments 54 having the same depth d. As can be seen in FIGS. 3 and 4, the protruding portion of the tongue is completely absent at the location of said receiving cavity 42, such that no weak, easily damaged portions remain at the edge or corner. Here, the depth d of the hollow receiving cavity 42 is substantially the same as the thickness T.sub.t of the tongue 26. Said tongue 26 and groove 28 comprise locking elements 82, 84 which prevent the tongue 26 and groove 27 from moving apart in a coupled condition, wherein said locking elements 82, 84 comprise an upwardly directed locking element 82 on the lower lip 32 and a downwardly directed locking element 84, which forms said protrusion 36, on the tongue 26 cooperating with said upwardly directed locking element 82 and wherein, in a coupled condition, a contact surface is formed between the top 83 of the tongue 26 and the bottom of the upper lip 32. The thickness T.sub.t of the tongue 26 is the dimension of the tongue 26 in a direction perpendicular to the plane of the floor panel from the said contact surface to the lowest point of the downwardly directed locking element 84 of the tongue 26. The top of said receiving pocket 48 extends at the height of said contact surface, thus at the height of the top 83 of the tongue 26. The thickness T.sub.up of the part of the panel situated above the the receiving pocket 48, being the dimension in a direction perpendicular to the plane of the floor covering, between the top of the panel and the receiving pocket 48 is at least 1.2 mm, preferably at least 1.5 mm, more preferably at least 1.7 mm. The part of the panel situated above the the receiving pocket 48 is the part of the panel situated above the tongue 26.
[0099] FIGS. 34 and 36 show details of FIG. 3 and FIGS. 33 and 35 show possible variants of the embodiment shown in FIG. 3. In FIG. 33 the depth d of the hollow receiving cavity 42 is smaller than the thickness T.sub.t of the tongue 26. In FIGS. 34 to 36 the depth d of the hollow receiving cavity 42 equals the thickness T.sub.t of the tongue 26. However embodiments where the depth d of the hollow receiving cavity 42 is slightly larger than the thickness T.sub.t of the tongue 26, for example between 0.01 and 0.2 mm larger than the thickness T.sub.t of the tongue 26, are also possible. As can be seen in FIG. 35, the tongue 26 is situated lower than in FIG. 34, such that the the thickness T.sub.up of the part of the panel situated above the the receiving pocket 48, thus above the tongue 26, is larger in FIG. 35 then in FIG. 34. The thickness T.sub.t of the tongue 26 can for example be between 1 mm and 1.5 mm, for example approximately 1.2 or 1.3 or 1.4 mm. The thickness T.sub.up of the part of the panel situated above the receiving pocket 48 can be at least 1.5 mm, preferably at least 1.7 mm and preferably more than 1.8 mm or 2 mm. The total thickness T of the panel can be for example 3.5 mm or 4 mm or 4.5 mm or 5 mm.
[0100] With respect to FIGS. 15 to 19 it is remarked that the jumper tool 70 is shown as a separate device positioned after the exit of the respective end-tenoner 66. This is not necessarily the case. The jumper tool 70 may be integrated in the end-tenoner 66 in place of a regular milling tool position. In any case, it is preferred that the panel is being transported past the jumper tool 70 by the same transporting mechanism as used to transport the panel through the end-tenoner 66, for example by means of being clamped between a lower chain transporting device having cams 68, and an upper belt. In case of FIGS. 15 to 19 the transporting mechanism of the end-tenoner 66 thus preferably also exits the end-tenoner 66 and extends past said jumper tools 70, without interruptions.
[0101] To fit in the receiving pockets 48 and receiving compartments 54, the alignment elements 46 are generally planar and have a thickness t.sub.c which, depending on how snug a fit is desired, is preferably no greater than the depth d of the hollow receiving cavities. In some embodiments, particularly when coupling of adjacent edges of two floor panels is performed with a vertical component of movement, it may be advantageous if the thickness t.sub.c of the alignment elements 46 is less than the depth d of the hollow receiving cavities to thereby allow for some vertical displacement of the alignment elements during joining. Thus, the thickness t.sub.c of the alignment element may be at least 50%, or at least 60%, or at least 70%, or at least 80% of at least 90% of the depth d of the hollow receiving cavities.
[0102] Providing hollow receiving cavities at the corners 23 of each floor panel 12 is particularly useful for aligning edges at the meeting point 52 of four floor panels. Nevertheless, improved alignment of panels can be attained even when the hollow receiving cavities 42 are at one or more locations along one or both pairs of opposite edges. Thus, in one embodiment, and as is depicted in FIG. 20, a hollow receiving cavity 42 is provided midway along each edge 16, 18, 20 22. As schematically shown in FIG. 21, when two panels A, B are connected together at adjacent edges such that two hollow receiving cavities are aligned with each other, a receiving pocket 48 will be formed. The receiving pocket 48 is adapted to accommodate an alignment element 46 of corresponding shape. The hollow receiving cavities 42 are suitably formed using the same equipment described above in relation to FIGS. 15 to 19, it being understood that both the first and the second end-tenoners 60, 66 will each require a dedicated pair of jumper tools should hollow receiving cavities be desired at all edges. Thus, the jumper tools 70 will be deployed first when the floor panel is approaching half-way through its passage of each of the end-tenoners 60, 66. Because the floor panel 12 is moving when the jumper tools are deployed, the hollow receiving cavities 42 will have a greater dimension along the respective edge than into the core 38 of the floor panel, approximating an essentially flattened bell-curve shape.
[0103] FIGS. 22 and 23 further illustrate the use of an alignment element 46 having equal quadrants. In FIG. 23 the panels 12 are installed in a row with alternating orientation, i.e. alternatingly coupling first edges 16 and fourth edges 22, with coupling third edges 20 and second edges 18 to form said row. Upon choice of the installer, the panels 12 illustrated here may also be installed without alternating the orientation of the panels 12, i.e. by coupling first edges 16 to second edges 18. The alignment element 46 can be used in either installation. Preferably the coupling means at the first edges 16 and the third edges 20 have a similar, potentially identical, configuration that is at least compatible with the configuration of the coupling means at both the second edges 18 and fourth edges 22.
[0104] With reference to the examples in the drawings, it is remarked that the hollow receiving cavities 42 are at least present at a central location of the thickness of the floor panel 12, wherein said receiving cavities 42, in the examples, are provided at such location in the thickness of the floor panel 12 that they interfere with a portion of the tongue 26 that protrudes beyond the edge of the decorative surface 14. In these cases, said protruding portion of the tongue 26 is completely absent at the location of said hollow receiving cavity 42. The receiving cavities 42 further interfere with a portion of the lower lip 32 that protrudes beyond said decorative surface 14, more particularly with the upwardly protruding part at the distal end of the lower lip 32 that borders said recess 34.
[0105] According to a special embodiment, illustrated in FIGS. 24 and 25, the panels 12 are square, wherein the first edge 16 and the second edge 18 that form said first pair of opposite edges may both be provided with an identical or similar coupling means, for example both with a male coupling part, for example, as is the case her, a tongue 26 as described in connection with the previous drawings, while the third edge 20 and the fourth edge 22 that form the second pair of opposite edges, are also both provided with an identical or similar coupling means, that is complimentary to the coupling means at said first pair of opposite edges 16-20, for example, as is the case here, both with a female coupling part, for example a groove 28 as described in connection with the previous drawings. Such embodiment still allows an installation in a chessboard pattern, as shown in exploited view in FIG. 25. Preferably such panels 12 are used with receiving compartments and alignment elements 46 that are formed from four equal quadrants, for example such as illustrated in FIGS. 13, 14, and 22 to 25.
[0106] According to a deviating embodiment of the present invention, a floor covering assembled from such square panels 12, as illustrated in FIG. 24 does not necessarily show the feature that they comprise a plurality of alignment elements 46 wherein at least one edge of said floor panel 12 at least partially defines a hollow receiving cavity 42 forming a receiving pocket 48 within which an alignment element 46 can at least partially be received. Indeed, in such case, the alternating use of tongues 26 and grooves 28 along joint grid lines 74 in the floor covering may provide for a certain maintenance of the alignment in the chessboard pattern. An installation of the panels 12 from FIG. 22 in the chessboard pattern as shown exploited in FIG. 23, though without the receiving pockets 48 and/or pertaining alignment elements 46, may lead to a similar maintenance in the pattern, since, in that case, a similar alternating use of tongues 26 and grooves 28 is present along joint grid lines 74 of the floor covering.
[0107] FIGS. 26 to 28 show a further embodiment pertaining to the invention, where the hollow receiving cavities 42 are L-shaped and form a cross-shaped receiving pocket 48. The L-shaped cavities of this example have equal length at both edges intersecting the respective corner where the cavity is provided. The alignment element 46 may in such case basically be formed as a Greek cross, as is the case in the example of FIG. 28. In this case the alignment element 46 is provided with ridges 76 to allow for a positioning in contact with stop surfaces 78 adjacent to the receiving cavity 42.
[0108] It is noted that in FIG. 26 the panels 12 are shown with alternating orientation, though this is not necessarily so. In the example, the receiving cavities 42 and the alignment element 46 have equal quadrants such that an alternating orientation in a row can straightforwardly be obtained.
[0109] The invention has been described above with reference to various embodiments. It is to be understood, however, that the embodiments are presented by way of example only and that the skilled person will appreciate that the floor covering of the present invention may be varied in many ways. For example, although the hollow receiving cavities have been described as forming a closed or substantially closed receiving compartment, the invention may still be practiced if the hollow receiving cavities are open in a direction towards the subfloor onto which the floor covering is to be laid. In this manner, the alignment elements will be supported from beneath by the subfloor. The invention may also be practised when the hollow receiving cavities are open in a direction towards the decorative surface. Preferably, however, such open cavities are then subsequently hidden from sight, for example by means of a grout applied in a space available between the upper edges of the joint panels, wherein said grout at least closes the opening of the hollow receiving cavity towards said decorative surface.
