Abstract
Floorboards with a mechanical locking system that allows movement between the floorboards when they are joined to form a floating floor. A semi-floating floor including rectangular floorboards joined with a mechanical locking system and in which locking system the joined floorboards have a horizontal plane which is parallel to a floor surface and a vertical plane which is perpendicular to the horizontal plane, said locking system having mechanically cooperating locks for vertical joining parallel to the vertical plane and for horizontal joining parallel to the horizontal plane of a first and a second joint edge and in which locking system a vertical lock including a tongue which cooperates with a tongue groove and the horizontal lock including a locking element with a locking surface which cooperates with a locking groove.
Claims
1. A method for producing a building panel having a horizontal plane which is parallel with a front side surface of the building panel, wherein the method comprises: displacing the building panel in a feeding direction relative a tool set and a pressure shoe, via a chain and a belt, pressing on a rear side of the building panel via the pressure shoe, forming an edge portion of the building panel via a first tool of the tool set, when the building panel is displaced relative the tool set, forming a guiding surface in the building panel via a second tool of the tool set, and guiding the building panel via a guiding device of the pressure shoe which cooperates with the guiding surface.
2. The method as claimed in claim 1, wherein the guiding prevents deviations in a direction perpendicular to the feeding direction and parallel to the horizontal plane.
3. The method as claimed in claim 1, further comprising forming, via the tool set, a mechanical locking system comprising a locking element at a first edge of the building panel and a locking groove at a second edge of the building panel for locking the building panel horizontally parallel to the horizontal plane.
4. The method as claimed in claim 3, wherein the guiding surface is a guiding groove open towards the rear side of the building panel.
5. The method as claimed in claim 4, wherein the guiding groove is a part of the mechanical locking system.
6. The method as claimed in claim 3, wherein the guiding surface is a part of the locking groove.
7. The method as claimed in claim 1, wherein the building panel is a floorboard.
8. The method as claimed in claim 1, wherein the second tool of the tool set is attached to a side of the pressure shoe.
9. The method as claimed in claim 1, wherein the first tool of the tool set is unattached to a side of the pressure shoe.
10. The method as claimed in claim 1, wherein the building panel is guided via two guiding devices on opposite sides of the building panel.
11. The method as claimed in claim 1, further comprising supporting the front side surface of the building panel via a support.
12. The method as claimed in claim 1, wherein the belt is provided on the rear side of the building panel with the pressure shoe.
13. The method as claimed in claim 1, wherein the belt travels through a recess in the pressure shoe.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) FIGS. 1a-1b show floorboards with locking system.
(2) FIGS. 2a-2f show locking systems and laying patterns.
(3) FIGS. 3a-3e show locking systems.
(4) FIGS. 4a-4c show locking systems.
(5) FIGS. 5a-5d show joined floorboards and testing methods.
(6) FIGS. 6a-6e show locking systems.
(7) FIGS. 7a-7e show locking systems.
(8) FIGS. 8a-8f show locking systems.
(9) FIGS. 9a-9d show locking systems.
(10) FIGS. 10a-10d show production equipment
(11) FIGS. 11a-11d show production equipment
(12) FIGS. 12a-12c show locking system.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
(13) FIGS. 1a and 1b illustrate floorboards which are of a first type A and a second type B according to the invention and whose long sides 4a and 4b in this embodiment have a length which is 3 times the length of the short sides 5a, 5b. The long sides 4a, 4b of the floorboards have vertical and horizontal connectors, and the short sides 5a, 5b of the floorboards have horizontal connectors. In this embodiment, the two types are identical except that the location of the locks is mirror-inverted. The locks allow joining of long side 4a to long side 4b by at least inward angling and long side 4a to short side 5a by inward angling, and also short side 5b to long side 4b by a vertical motion. Joining of both long sides 4a, 4b and short sides 5a, 5b in a herringbone pattern or in parallel rows can in this embodiment take place merely by an angular motion along the long sides 4a, 4b. The long sides 4a, 4b of the floorboards have connectors, which in this embodiment comprising a strip 6, a tongue groove 9 and a tongue 10. The short sides 5a also have a strip 6 and a tongue groove 9 whereas the short sides 5b have no tongue 10. There may be a plurality of variants. The two types of floorboards need not be of the same format and the locking means can also have different shapes, provided that as stated above they can be joined long side against short side. The connectors can be made of the same material, or of different materials, or be made of the same material but with different material properties. For instance, the connectors can be made of plastic or metal. They can also be made of the same material as the floorboard, but be subjected to a treatment modifying their properties, such as impregnation or the like. The short sides 5b can have a tongue and the floorboards can then be joined in prior-art manner in a diamond pattern by different combinations of angular motion and snap motions. Short sides could also have a separate flexible tongue, which during locking could be displaced horizontally.
(14) FIG. 2a shows the connectors of two floorboards 1, 1 that are joined to each other. In this embodiment, the floorboards have a surface layer 31 of laminate, a core 30 of, for instance, HDF, which is softer and more compressible than the surface layer 31, and a balancing layer 32. The vertical locking D1 comprises a tongue groove 9, which cooperates with a tongue 10. The horizontal locking D2 comprises a strip 6 with a locking element 8, which cooperates with a locking groove 12. This locking system can be joined by inward angling along upper joint edges. It could also be modified in such a way that it could be locked by horizontal snapping. The locking element 8 and the locking groove 12 have cooperating locking surfaces 15, 14. The floorboards can, when joined and pressed against each other in the horizontal direction D2, assume a position where there is a play 20 between the locking surfaces 14, 15. FIG. 2b show that when the floorboards are pulled apart in the opposite direction, and when the locking surfaces 14, 15 are in complete contact and pressed against each other, a joint gap 21 arises in the front side between the upper joint edges. The play between the locking surfaces 14, 15 are defined as equal to the displacement of the upper joint edges when these edges are pressed together and pulled apart as described above. This play in the locking system is the maximum floor movement that takes place when the floorboards are pressed together and pulled apart with a pressure and pulling force adapted to the strength of the edge portions and the locking system. Floorboards with hard surface layers or edges, which when pressed together are only compressed marginally, will according to this definition have a play, which is essentially equal or slightly larger than the join gap. Floorboards with softer edges will have a play which is considerable larger than the joint gap. According to this definition, the play is always larger or equal to the joint gap. The play and joint gap can be, for example, 0.05-0.10 mm. Joint gaps, which are about 0.1 mm, are considered acceptable. They are difficult to see and normal dirt particles are too big to penetrate into the locking system through such small joint gaps. In some applications joint gaps up to 0.20 mm, with a play of for example 0.25 mm could be accepted, especially if play and joint gaps are measured when a considerable pressure and pulling force is used. This maximum joint gap will occur in extreme conditions only when the humidity is very low, for example below 20% and when the load on the floor is very high. In normal condition and applications the joint gap in such a floor could be 0.10 mm or less.
(15) FIG. 2b shows an ordinary laminate floor with floorboards in the size of 1.2*0.2 m, which are installed in parallel rows. Such a laminate floor shrinks and swells about 1 mm per meter. If the locking system has a play of about 0.1 mm, the five joints in the transverse direction D2 B will allow swelling and shrinking of 5*0.1=0.5 mm per meter. This compensates for only half the maximum swelling or shrinking of 1 mm. In the longitudinal direction D2 A, there is only one joint per 1.2 m, which allows a movement of 0.1 mm. The play 20 and the joint gap 21 in the locking system thus contribute only marginally to reduce shrinking and swelling of the floor in the direction D2 parallel to the long sides. To reduce the movement of the floor to half of the movement that usually occurs in a floor without play 20 and joint gap 21, it is necessary to increase the play 20 to 0.6 mm, and this results in too big a joint gap 21 on the short side.
(16) FIG. 2c shows floorboards with, for instance, a core 30 of fiberboard, such as HDF, and a surface layer of laminate or veneer, which has a maximum dimensional change of about 0.1%, i.e., 1 mm per meter. The floorboards are installed in parallel rows. In this embodiment, they are narrow and short with a size of, for example, 0.5*0.08 m. If the play is 0.1 mm, 12 floorboards with their 12 joints over a floor length of one meter will allow a movement in the transverse direction D2 B of 1.2 mm, which is more than the maximum dimensional change of the floor. Thus the entire movement may occur by the floorboards moving relative to each other, and the outer dimensions of the floor can be unchanged. In the longitudinal direction D2 A, the two short side joints can only compensate for a movement of 0.2 mm per meter. In a room which is, for example, 10 m wide and 40 m long, installation can suitably occur, contrary to the present recommended installation principles, with the long sides of the floorboards parallel to the width direction of the room and perpendicular to the length direction thereof. According to this preferred embodiment, a large continuous floating floor surface without large visible joint gaps can thus be provided with narrow floorboards which have a locking system with play and which are joined in parallel rows perpendicular to the length direction of the floor surface. The locking system, the floorboards and the installation pattern should thus be adjusted so that a floor surface of 1*1 m can expand and be pressed together about 1 mm or more in at least one direction without damaging the locking system or the floorboards. A mechanical locking system in a floating floor which is installed in home settings should have a mechanical locking system that withstands tensile load and compression corresponding to at least 200 kg per meter of floor length. More specifically, it should preferably be possible to achieve the above change in shape without visible joint gaps when the floor surface above is subjected to a compressive or tensile load of 200 kg in any direction and when the floorboards are conditioned in normal relative humidity of about 45%.
(17) The strength of a mechanical locking system is of great importance in large continuous floating floor surfaces. Such large continuous surfaces are defined as a floor surface with length and/or width exceeding 12 m. Very large continuous surfaces are defined as floor surfaces with length and/or width exceeding 20 m. There is a risk that unacceptable joint gaps will occur or that the floorboards will slide apart, if the mechanical locking system is not sufficiently strong in a large floating floor. Dimensionally stable floorboards, such as laminate floors, which show average joint gaps exceeding 0.2 mm, when a tensile load of 200 kg/m is applied, are generally not suitable to use in a large high quality floating floor. The invention could be used to install continuous floating floors with a length and/or width exceeding 20 m or even 40 m. In principle there are no limitations. Continuous floating floors with a surface of 10,000 m.sup.2 or more could be installed according to invention.
(18) Such new types of floating floors where the major part of the floating movement, in at least one direction, takes place between the floorboards and in the mechanical locking system are hereafter referred to as Semi-floating Floors.
(19) FIG. 5d illustrates a suitable testing method in order to ensure that the floorboards are sufficiently mobile in the joined state and that the locking system is strong enough to be used in a large continuous floating floor surface where the floor is a Semi Floating Floor. In this example, 9 samples with 10 joints and with a length L of 100 mm (10% of 1 meter) have been joined along their respective long sides so as to correspond to a floor length TL of about 1 meter. The amount of joints, in this example, 10 joints, is referred to as Nj. The boards are subjected to compressive and tensile load using a force F corresponding to 20 kg (200 N), which is 10% of 200 kg. The change in length of the floor length TL, hereafter referred to as TL, should be measured. The average play, hereafter referred to as AP or floor movement per joint is defined as AP=TL/Nj. If for example TL=1.5 mm, than the average play AP=1.5/10=0.15 mm. This testing method will also measure dimensional changes of the floorboard. Such dimensional changes are in most floorboards extremely small compared to the play. As mentioned before, due to compression of top edges and eventually some very small dimensional changes of the floor board itself, the average joint gap will always be smaller than the average play AP. This means that in order to make sure that the floor movement is sufficient (TL) and that the average joint gaps 21 do not exceed the stipulated maximum levels, only TL has to be measured and controlled, since TL/Nj is always larger or equal to the average joint gap 21. The size of the actual average joint gap 21 in the floor, when the tensile force F is applied, could however be measured directly for example with a set of thickness gauges or a microscope and the actual average joint gap=AAJG could be calculated. The difference between AP and AAJG is defined as floorboard flexibility=FF (FF=APAAJG). In a laminate floor TL should preferably exceed 1 mm. Lower or higher force F could be used to design floorboards, installation patterns and locking systems which could be used as Semi Floating Floors. In some applications for example in home environment with normal moisture conditions a force F of 100 kg (1000 N) per meter could be sufficient. In very large floating floors a force F of 250-300 kg or more could be used. Mechanical locking systems could be designed with a locking force of 1000 kg or more. The joint gap in such locking systems could be limited to 0.2 mm even when a force F of 400-500 kg is applied. The pushback effect caused by the locking element 8, the locking surfaces 15,14 and the locking strip 6 could be measured by increasing and decreasing the force F in steps of for example 100 kg. The pushback effect is high If TL is essentially the same when F is increased from 0 to 100 kg (=TL1) as when F is increased from 0 to 200 kg and then decreased back to 100 kg (=TL2). A mechanical locking system with a high pushback effect is an advantage in a semi-floating floor. Preferably TL1 should be at least 75% of TL2. In some applications even 50% could be sufficient.
(20) FIG. 2d shows floorboards according to FIG. 2c which are installed in a diamond pattern. This method of installation results in 7 joints per running meter in both directions D2 A and D2 B of the floor. A play of 0.14 mm can then completely eliminate a swelling and shrinking of 0.1% since 7 joints result in a total mobility of 7*0.14=1.0 mm.
(21) FIG. 2e shows floor surface of one square meter which consists of the above-described floorboards installed in a herringbone pattern long side against short side and shows the position of the floorboards when, for instance, in summer they have swelled to their maximum dimension. FIG. 2f shows the position of the floorboards when, for instance, in winter, they have shrunk. The locking system with the inherent play then results in a joint gap 21 between all joint edges of the floorboards. Since the floorboards are installed in a herringbone pattern, the play of the long sides will help to reduce the dimensional changes of the floor in all directions. FIG. 2f also shows that the critical direction is the diagonal directions D2 C and D2 D of the floor where 7 joint gaps must be adjusted so as to withstand a shrinkage over a distance of 1.4 m. This can be used to determine the optimal direction of laying in a large floor. In this example, a joint gap of 0.2 mm will completely eliminate the movement of the floor in all directions. This allows the outer portions of a floating floor to be attached to the subfloor, for example, by gluing, which prevents the floor, when shrinking, to be moved outside the baseboards. The invention also allows partition walls to be attached to an installed floating floor, which can reduce the installation time.
(22) Practical experiments demonstrate that a floor with a surface of veneer or laminate and with a core of a fiberboard-based panel, for instance a dimensionally stable high quality HDF, can be manufactured so as to be highly dimensionally stable and have a maximum dimensional change in home settings of about 0.5-1.0 mm per meter. Such semi-floating floors can be installed in spaces of unlimited size, and the maximum play can be limited to about 0.1 mm also in the cases where the floorboards have a width of preferably about 120 mm. It goes without saying that still smaller floorboards, for instance 0.4*0.06 m, are still more favorable and can manage large surfaces also when they are made of materials that are less stable in shape. According to a first embodiment, a new type of semi-floating floor where the individual floorboards are capable of moving and where the outer dimensions of the floor need not be changed. This can be achieved by optimal utilization of the size of the boards, the mobility of the locking system using a small play and a small joint gap, and the installation pattern of the floorboards. A suitable combination of play, joint gap, size of the floorboard, installation pattern and direction of laying of the floorboards can thus be used in order to wholly or partly eliminate movements in a floating floor. Much larger continuous floating floors can be installed than is possible today, and the maximum movement of the floor can be reduced to the about 10 mm that apply to current technology, or be completely eliminated. All this can occur with a joint gap which in practice is not visible and which is not different, regarding moisture and dirt penetration, from traditional 0.2 m wide floating floorboards which are joined in parallel rows by pretension or with a very small displacement play which does not give sufficient mobility. As a non-limiting example, it can be mentioned that the play 20 and the joint gap 21 in dimensionally stable floors should preferably be about 0.1-0.2 mm.
(23) An especially preferred embodiment according to the invention is a semi-floating floor with the following characteristics: The surface layer is laminate or wood veneer, the core of the floorboard is a wood based board such as MDF or HDF, the change in floor length TL is at least 1.0 mm when a force F of 100 kg/m is used, the change in floor length TL is at least 1.5 mm when a force F of 200 kg/m is used, average joint gaps do not exceed 0.15 mm when the force F is 100 kg/m and they do not exceed 0.20 mm when the force F is 200 kg/m.
(24) The function and joint quality of such semi-floating floorboards will be similar to traditional floating floorboards when humidity conditions are normal and the size of the floor surface is within the generally recommended limits. In extreme climate conditions or when installed in a much larger continuous floor surface, such semi-floating floorboard will be superior to the traditional floorboards. Other combinations of force F, change in floor length TL and joint gap 21 could be used in order to design a semi-floating floor for various application.
(25) FIG. 3a shows a second embodiment, which can be used to counteract the problems caused by movements due to moisture in floating floors. In this embodiment, the floorboard has a surface 31 of direct laminate and a core of HDF. Under the laminate surface, there is a layer 33, which consists of melamine impregnated wood fibers. This layer forms, when the surface layer is laminated to HDF and when melamine penetrates into the core and joins the surface layer to the HDF core. The HDF core 30 is softer and more compressible than the laminate surface 31 and the melamine layer 33. According to the invention, the surface layer 31 of laminate and, where appropriate, also parts of, or the entire, melamine layer 33 under the surface layer can be removed so that a decorative groove 133 forms in the shape of a shallow joint opening JO 1. This joint opening resembles a large joint gap in homogeneous wooden floors. The groove 133 can be made on one joint edge only, and it can be colored, coated or impregnated in such a manner that the joint gap becomes less visible. Such decorative grooves or joint openings can have, for example, a width JO 1 of, for example, 1-3 mm and a depth of 0.2-0.5 mm. In some application the width of JO 1 could preferably be rather small about 0.5-1.0 mm When the floorboards 1, 1 are pressed towards each other, the upper joint edges 16, 17 can be compressed. Such compression can be 0.1 mm in HDF. Such a possibility of compression can replace the above-mentioned play and can allow a movement without a joint gap. Chemical processing as mentioned above can also change the properties of the joint edge portion and help to improve the possibilities of compression. Of course, the first and second embodiment can be combined. With a play of 0.1 mm and a possibility of compression of 0.1 mm, a total movement of 0.2 mm can be provided with a visible joint gap of 0.1 mm only. Compression can also be used between the active locking surfaces 15, 14 in the locking element 8 and in the locking groove 12. In normal climatic conditions the separation of the floorboards is prevented when the locking surfaces 14, 15 are in contact with each other and no substantial compression occurs. When subjected to additional tensile load in extreme climatic conditions, for instance when the RH falls below 25%, the locking surfaces will be compressed. This compression is facilitated if the contact surface CS of the locking surfaces 14, 15 are small. It is advantageous if this contact surface CS in normal floor thicknesses 8-15 mm is about 1 mm or less. With this technique, floorboards can be manufactured with a play and joint gap of about 0.1 mm. In extreme climatic conditions, when the RH falls below 25% and exceeds 80%, compression of upper joint edges and locking surfaces can allow a movement of for instance 0.3 mm. The above technique can be applied to many different types of floors, for instance floors with a surface of high pressure laminate, wood, veneer and plastic and like materials. The technique is particularly suitable in floorboards where it is possible to increase the compression of the upper joint edges by removing part of the upper joint edge portion 16 and/or 17.
(26) FIG. 3b illustrates a third embodiment. FIGS. 3c and 3d are enlargements of the joint edges in FIG. 3b. The floorboard 1 has, in an area in the joint edge which is defined by the upper parts of the tongue 10 and the groove 9 and the floor surface 31, an upper joint edge portion 18 and a lower joint edge portion 17, and the floorboard 1 has in a corresponding area an upper joint edge portion 19 and a lower joint edge portion 16. When the floorboards 1, 1 are pressed together, the lower joint edge portions 16, 17 will come into contact with each other. This is shown in FIG. 3d. The upper joint edge portions 18, 19 are spaced from each other, and one upper joint edge portion 18 of one floorboard 1 overlaps the lower joint edge portion 16 of the other floorboard 1. In this pressed-together position, the locking system has a play 20 of for instance 0.2 mm between the locking surfaces 14, 15. If the overlap in this pressed-together position is 0.2 mm, the boards can, when being pulled apart, separate from each other 0.2 mm without a visible joint gap being seen from the surface. This embodiment will not have an open joint gap because the joint gap will be covered by the overlapping joint edge portion 18. This is shown in FIG. 3c. It is an advantage if the locking element 8 and the locking grove 12 are such that the possible separation i.e. e. the play is slightly smaller than the overlapping. Preferably a small overlapping, for example 0.05 mm should exist in the joint even when the floorboards are pulled apart and a pulling force F is applied to the joint. This overlapping will prevent moisture to penetrate into the joint. The joint edges will be stronger since the lower edge portion 16 will support the upper edge portion 18. The decorative groove 133 can be made very shallow and all dirt collecting in the groove can easily be removed by a vacuum cleaner in connection with normal cleaning. No dirt or moisture can penetrate into the locking system and down to the tongue 12. This technique involving overlapping joint edge portions can, of course, be combined with the two other embodiments on the same side or on long and short sides. The long side could for instance have a locking system according to the first embodiment and the short side according to the second. For example, the visible and open joint gap can be 0.1 mm, the compression 0.1 mm and the overlap 0.1 mm. The floorboards' possibility of moving will then be 0.3 mm all together and this considerable movement can be combined with a small visible open joint gap and a limited horizontal extent of the overlapping joint edge portion 18 that does not have to constitute a weakening of the joint edge. This is due to the fact that the overlapping joint edge portion 18 is very small and also made in the strongest part of the floorboard, which consists of the laminate surface, and melamine impregnated wood fibers. Such a locking system, which thus can provide a considerable possibility of movement without visible joint gaps, can be used in all the applications described above. Furthermore the locking system is especially suitable for use in broad floorboards, on the short sides, when the floorboards are installed in parallel rows and the like, i.e., in all the applications that require great mobility in the locking system to counteract the dimensional change of the floor. It can also be used in the short sides of floorboards, which constitute a frame FR, or frieze round a floor installed in a herringbone pattern according to FIG. 5c. In this embodiment, shown in FIGS. 3b-3d, the vertical extent of the overlapping joint edge portion, i.e., the depth GD of the joint opening, is less than 0.1 times the floor thickness T. An especially preferred embodiment according to the invention is a semi-floating floor with the following characteristics: The surface layer is laminate or wood veneer, the core of the floorboard is a wood based board such as MDF or HDF, the floor thickness T is 6-9 mm and the overlapping OL is smaller than the average play AP when a force F of 100 kg/m is used. As an example it could be mentioned that the depth GD of the joint opening could be 0.2-0.5 mm (=0.02*T0.08 T). The overlapping OL could be 0.1-0.3 mm (=0.01*T0.05*T) on long sides. The overlapping OL on the short sides could be equal or larger than the overlapping on the long sides.
(27) FIG. 3e show an embodiment where the joint opening JO 1 is very small or nonexistent when the floorboards are pressed together. When the floorboards are pulled apart, a joint opening JO 1 will occur. This joint opening will be substantially of the same size as the average play AP. The decorative groove could for example be colored in some suitable design matching the floor surface and a play will not cause an open joint gap. A very small overlapping OL of some 0.1 mm (0.01*T0.02*T) only and slightly smaller average play AP could give sufficient floor movement and this could be combined with a moisture resistant high quality joint. The play will also facilitate locking, unlocking and displacement in locked position. Such overlapping edge portions could be used in all known mechanical locking systems in order to improve the function of the mechanical locking system.
(28) FIGS. 4a and 4b show how a locking system can be designed so as to allow a floating installation of floor-boards, which comprise a moisture sensitive material. In this embodiment, the floorboard is made of homogeneous wood.
(29) FIG. 4a shows the locking system in a state subjected to tensile load, and FIG. 4b shows the locking system in the compressed state. For the floor to have an attractive appearance, the relative size of the joint openings should not differ much from each other. To ensure that the visible joint openings do not differ much while the floor moves, the smallest joint opening JO 2 should be greater than half the greatest joint opening JO 1. Moreover, the depth GD should preferably be less than 0.5*TT, TT being the distance between the floor surface and the upper parts of the tongue/groove. In the case where there is no tongue, GD should be less than 0.2 times the floor thickness T. This facilitates cleaning of the joint opening. It is also advantageous if JO 1 is about 1-5 mm, which corresponds to normal gaps in homogeneous wooden floors. According to the invention, the overlapping joint edge portion should preferably lie close to the floor surface. This allows a shallow joint opening while at the same time vertical locking can occur using a tongue 10 and a groove 9 which are placed essentially in the central parts of the floorboard between the front side and the rear side where the core 30 has good stability. An alternative way of providing a shallow joint opening, which allows movement, is illustrated in FIG. 4c. The upper part of the tongue 10 has been moved up towards the floor surface. The drawback of this solution is that the upper joint edge portion 18 above the tongue 10 will be far too weak. The joint edge portion 18 can easily crack or be deformed.
(30) FIGS. 5a and 5b illustrate the long side joint of three floorboards 1, 1 and 1 with the width W. FIG. 5a shows the floorboards where the RH is low, and FIG. 5b shows them when the RH is high. To resemble homogeneous floors, broad floorboards should preferably have wider joint gaps than narrow ones. JO 2 should suitably be at least about 1% of the floor width W. 100 mm wide floorboards will then have a smallest joint opening of at least 1 mm. Corresponding joint openings in, for example, 200 mm wide planks should be at least 2 mm. Other combinations can, of course, also be used especially in wooden floors where special requirements are made by different kinds of wood and different climatic conditions.
(31) FIG. 6a shows a wooden floor, which consists of several layers of wood. The floorboard may comprise, for example, an upper layer of high-grade wood, such as oak, which constitutes the decorative surface layer 31. The core 30 may comprise, for example, plywood, which is made up of other kinds of wood or by corresponding kinds of wood but of a different quality. Alternatively the core may comprise or wood lamellae. The upper layer 31 has as a rule a different fiber direction than a lower layer. In this embodiment, the overlapping joint edges 18 and 19 are made in the upper layer. The advantage is that the visible joint opening JO 1 will comprise the same kind of wood and fiber direction as the surface layer 31 and the appearance will be identical with that of a homogeneous wooden floor.
(32) FIGS. 6b and 6c illustrate an embodiment where there is a small play 22 between the overlapping joint edge portions 16, 18, which facilitate horizontal movement in the locking system. FIG. 6c shows joining by an angular motion and with the upper joint edge portions 18, 19 in contact with each other. The play 20 between the locking surface 15 of the locking element 8 and the locking groove 12 significantly facilitates joining by inward angling, especially in wooden floors that are not always straight.
(33) In the above-preferred embodiments, the overlapping joint portion 18 is made in the tongue side, i.e., in the joint edge having a tongue 10. This overlapping joint portion 18 can also be made in the groove side, i.e., in the joint edge having a groove 9. FIGS. 6d and 6e illustrate such an embodiment. In FIG. 6d, the boards are pressed together in their inner position, and in FIG. 6e they are pulled out to their outer position.
(34) FIGS. 7a-7b illustrate that it is advantageous if the upper joint edge 18, which overlaps the lower 16, is located on the tongue side 4a. The groove side 4b can then be joined by a vertical motion to a side 4a, which has no tongue, according to FIG. 7b. Such a locking system is especially suitable on the short side. FIG. 7c shows such a locking system in the joined and pressed-together state. FIGS. 7d and 7e illustrate how the horizontal locks, for instance in the form of a strip 6 and a locking element 8 and also an upper and lower joint portion 19, 16, can be made by merely one tool TO which has a horizontally operating tool shaft HT and which thus can form the entire joint edge. Such a tool can be mounted, for example, on a circular saw, and a high quality joint system can be made by means of a guide bar. The tool can also saw off the floorboard 1. In the preferred embodiment, only a partial dividing of the floorboard 1 is made at the outer portion 24 of the strip 6. The final dividing is made by the floorboard being broken off. This reduces the risk of the tool TO being damaged by contacting a subfloor of, for instance, concrete. This technique can be used to produce a frame or freeze FR in a floor, which, for instance, is installed in a herringbone pattern according to FIG. 5c. The tool can also be used to manufacture a locking system of a traditional type without overlapping joint edge portions.
(35) FIGS. 8a-8f illustrate different embodiments. FIGS. 8a-8c illustrate how the invention can be used in locking systems where the horizontal lock comprises a tongue 10 with a locking element 8 which cooperates with a locking groove 12 made in a groove 9 which is defined by an upper lip 23 and where the locking groove 12 is positioned in the upper lip 23. The groove also has a lower lip 24 which can be removed to allow joining by a vertical motion. FIG. 8d shows a locking system with a separate strip 6, which is made, for instance, of aluminum sheet. FIG. 8e illustrates a locking system that has a separate strip 6 which can be made of a fiberboard-based material or of plastic, metal and like materials.
(36) FIG. 8f shows a locking system, which can be joined by horizontal snap action. The tongue 10 has a groove 9 which allows its upper and lower part with the locking elements 8, 8 to bend towards each other in connection with horizontally displacement of the joint edges 4a and 4b towards each other. In this embodiment, the upper and lower lip 23, 24 in the groove 9 need not be resilient. Of course, the invention can also be used in conventional snap systems where the lips 23, 24 can be resilient.
(37) FIGS. 9a-9d illustrate alternative embodiments of the invention. When the boards are pulled apart, separation of the cooperating locking surfaces 14 and 15 is prevented. When boards are pressed together, several alternative parts in the locking system can be used to define the inner position. In FIG. 9a, the inner position of the outer part of the locking element 8 and the locking groove 10 is determined. According to FIG. 9b, the outer part of the tongue 10 and the groove 9 cooperate. According to FIG. 9c the front and lower part of the tongue 10 cooperates with the groove 9. According to FIG. 9d, a locking element 10 on the lower part of the tongue 10 cooperates with a locking element 9 on the strip 6. It is obvious that several other parts in the locking system can be used according to these principles in order to define the inner position of the floorboards.
(38) FIG. 10a shows production equipments and production methods according to the invention. The end tenor ET has a chain 40 and a belt 41 which displace the floorboard 1 in a feeding direction FD relative a tool set, which in this embodiment has five tools 51,52,53,54 and 55 and pressure shoes 42. The end tenor could also have two chins and two belts. FIG. 10b is an enlargement of the first tooling station. The first tool 51 in the tool set makes a guiding surface 12 which in this embodiment is a groove and which is mainly formed as the locking groove 12 of the locking system. Of course other groves could be formed preferably in that part of the floorboard where the mechanical locking system will be formed. The pressure shoe 42 has a guiding device 43which cooperates with the groove 12 and prevents deviations from the feeding direction FD and in a plane parallel to the horizontal plane. FIG. 10c shows the end tenor seen from the feeding direction when the floorboard has passed the first tool 51. In this embodiment the locking groove 12 is used as a guiding surface for the guiding device 43, which is attached to the pressing shoe 42. The FIG. 10d shows that the same groove 12 could be used as a guiding surface in all tool stations. FIG. 10d shows how the tongue could be formed with a tool 54. The machining of a particular part of the floorboard 1 can take place when this part, at the same time, is guided by the guiding device 43. FIG. 11a shows another embodiment where the guiding device is attached inside the pressure shoe. The disadvantage is that the board will have a grove in the rear side. FIG. 11b shows another embodiment where one or both outer edges of the floorboard are used as a guiding surface for the guiding device 43, 43. The end tenor has in this embodiment support units 44, 44 which cooperate with the pressure shoes 42,42. The guiding device could alternatively be attached to this support units 44,44. FIGS. 11c and 11d shows how a floorboard could be produced in two steps. The tongue side 10 is formed in step one. The same guiding groove 12 is used in step 2 (FIG. 11d) when the groove side 9 is formed. Such an end tenor will be very flexible. The advantage is that floorboards of different widths, smaller or larger than the chain width, could be produced.
(39) FIGS. 12a-12c show a preferred embodiment which guaranties that a semi-floating floor will be installed in the normal position which preferably is a position where the actual joint gap is about 50% of the maximum joint gap. If for instance all floorboards are installed with edges 16, 17 in contact, problems may occur around the walls when the floorboards swell to their maximum size. The locking element and the locking groove could be formed in such a way that the floorboards are automatically guided in the optimal position during installation. FIG. 12c shows that the locking element 8 in this embodiment has a locking surface with a high locking angle LA close to 90 degree to the horizontal plane. This locking angle LA is higher than the angle of the tangent line TL to the circle C, which has a center at the upper joint edges. FIG. 12b shows that such a joint geometry will during angling push the floorboard 4a towards the floorboard 4b and bring it into the above-mentioned preferred position with a play between the locking element 8 and the locking groove 12 and a joint gap between the top edges 16, 17.
(40) Although only preferred embodiments are specifically illustrated and described herein, it will be appreciated that many modifications and variations of the present invention are possible in light of the above teachings and within the purview of the appended claims without departing from the spirit and intended scope of the invention.
