NO327717B1 - Floor system and floor plate to produce such a floor system. - Google Patents

Abstract

A floorboard and an openable locking system therefor comprise an undercut groove on one long side of the floorboard and a projecting tongue on the opposite long side of the floorboard. The undercut groove has a corresponding upwardly directed inner locking surface at a distance from its tip. The tongue and the undercut groove are formed to be brought together and pulled apart by a pivoting motion which has its centre (C) close to the intersection between the surface planes (HP) and the common joint plane (VP) of two adjoining floorboards. The undercut in the groove of such a locking system is produced by means of at least two disk-shaped cutting tools whose rotary shafts are inclined relative to each other to form first an inner part of the undercut portion of the groove and then a locking surface positioned closer to the opening of the groove. An installation method for a floor of such boards comprises the steps of laying a new board adjacent to a previously laid board, moving the tongue of the new board into the mouth of the undercut groove of the laid board, angling the new board upward during continued insertion of the tongue into the undercut groove and simultaneously angling down the new board to the final position. A manufacturing method for manufacturing the undercut groove uses machining by means of at least two different rotary cutting tools whose rotary shaft is set at different angles. A wedge-shaped tool for laying of the floorboards is wedge-shaped with an upwardly directed engaging surface at its thicker end.

Description

The present invention relates to a floor system as stated in the introduction of the independent claim.

Technical area

The present invention is particularly applicable to floorboards which are based on wood material and which usually have a core of wood, and which are intended to be assembled mechanically. The following description of prior art, and the purposes and properties of the invention are therefore aimed at this area of application and, primarily, rectangular parquet floors which are connected together on both the long side and the short side. The invention is particularly suitable for floating floors, i.e. floors that can be moved in relation to the base. Nevertheless, it must be emphasized that the invention can be used with all types of existing hard floors, such as homogeneous wooden floors, wooden floors with a lamella core or plywood core, floors with a veneer surface and a wood fiber core, thin laminated floors, floors with a plastic core, and the like . The invention can of course also be used for other types of floorboards that can be machined with cutting tools, such as subfloors made of plywood or chipboard. Although not preferred, after installation the floorboards can be attached to the base.

Technical background for the invention

Mechanical couplings have in a short time taken large market shares, mainly due to their superior laying properties, coupling strength and coupling quality. Although the floor according to W094/26999, which is described in more detail below, and the floor sold under the trademark Alloc© have great advantages compared to traditional glued floors, further improvements are still desirable.

Mechanical connection systems are very suitable for connecting not only laminate floors, but also wood and composite floors. Such floorboards can consist of a large number of different materials in the surface, core and back. As will be described below, these materials can also be included in the various parts of the coupling system, such as molding, locking element and tongue. A solution comprising an integrated strip which is shaped according to e.g. W094/26999 or W097/47834, and which produces the horizontal connection, and which also includes a tongue which provides the vertical connection, however results in costs in the form of material waste in connection with forming the mechanical connection when machining the plate material.

For optimal function, e.g. a 15 mm thick parquet floor has a strip with a width of approx. the same as the thickness of the floor, i.e. approx. 15 mm. With a tongue of approx. 3 mm, the amount of shrinkage will be 18 mm. The floor slab has a normal width of approx. 200 mm. Therefore, the amount of material waste will be approx. 9%. In general, the cost of the scrap material will be large if the floor slab consists of expensive materials, as they are thick or as the format is small, so that the number of running meters of coupling per m<2> floor will be large.

The amount of material waste can certainly be reduced if a strip is used that has the form of a separately manufactured aluminum strip that is already attached to the floor slab in the factory. Also, in a number of applications, the aluminum strip can result in a better and also cheaper locking system than a strip that is machined and formed from the core. Nevertheless, the aluminum strip is disadvantageous since the investment costs may be high, and further reconstruction of the factory may be necessary to convert an existing traditional production line, so that floorboards with such a mechanical connection system can be produced. An advantage of the known aluminum strip, however, is that the output format of the floorboards does not have to be changed.

Since it is about a molding produced by machining the material of the floorboard, the opposite is the case. Therefore, the format of the floorboards must be adjusted so that there is enough material to form the molding and tongue. For laminate floors, it is often necessary to also change the width of the decorative paper used. All these adjustments and changes also require expensive adaptations of the production equipment, and major product adaptations.

In addition to the above-mentioned problems related to unwanted material waste and costs of production and production adaptation, the list has disadvantages in that it is susceptible to damage during transport and installation.

To summarize, there is a great need to produce a mechanical coupling with a lower production cost, but at the same time the goal is to retain the current excellent properties regarding laying, removal, coupling quality and strength. With known solutions, it is not possible to achieve low costs without also having to lower the standards with regard to strength and/or laying function. One purpose of the invention is therefore to provide solutions which are aimed at reducing cost, while at the same time maintaining strength and function.

The invention originates in known floorboards which have a core, a front side, a back side and corresponding connecting edge parts, where one of them is formed as a tongue groove bounded by upper and lower lips and which has a lower end, and where the other is formed as a tongue with an upturned portion on its free outer end. The tongue groove is in the form of an incised groove with an opening, an inner part and an inner locking surface.

At least portions of the lower lip are formed integrally with the core of the floor plate, and the tongue has a locking surface which is designed to cooperate with the inner locking surface in the tongue groove of an adjacent floor plate, two such floor plates being mechanically connected so that their faces are in the same surface plane (HP) and meet in a connecting plane (VP) directed perpendicular to it. This technique is described, among other things, in DE-A-3041781, which will be described in more detail below.

However, first the general technique regarding floorboards and locking systems for mechanical interlocking of floorboards shall be described, as a background for the present invention.

Description of known technique

In order to enable the understanding and description of the present invention and also knowledge of the problems behind the invention, here follows a description of both the basic construction and the function of floor slabs according to W094/

26999 and W099/66151, with reference to Figures 1-17 in the accompanying drawings. In suitable parts, the following description of prior art also applies to embodiments of the present invention as described below.

Fig. 3a and 3b show a floor plate 1 according to WO94/26999 respectively. from the top and from the bottom. Plate 1 is square with an upper side 2, a lower side 3, two opposite long sides with locking edge parts 4a and 4b, and two opposite short sides with locking edge parts 5a and 5b.

The locking edge parts 4a, 4b of the long sides and also the locking edge parts 5a, 5b of the short sides can be connected mechanically without glue in a direction D2 in fig. lc, so as to meet in a connecting plane VP (marked in fig. 2c) to have, as they are laid, their upper sides in a common plane HP (marked in fig. 2c).

In the illustrated embodiment, which is an example of the floor plates according to W094/26999 (figures 1-3 in the accompanying drawings), the plate 1 has a factory-fitted flat strip 6 which protrudes along the entire long side 4a and which is made of a flexible, elastic aluminum plate . The strip 6 protrudes beyond the connection plane VP at the connection edge part 4a. The strip 6 can be attached mechanically according to the illustrated embodiment or else with glue or in another way. As described in the aforementioned documents, it is also possible to use other materials for a strip, which is attached to the floor plate in the factory, such as thin plate or other metal, aluminum or plastic sections. It is also claimed in W094/26999 and as described and illustrated in W099/66151, that the strip 6 can instead be formed integrally with the plate 1, e.g. by suitable machining of plate 1.

The present invention is suitable for floorboards where the strip or at least part of it is formed integrally with the core, and the invention solves special problems that arise in such floorboards and their production. The core of the floorboard does not need to be made of, but is preferably made of, a uniform material. Nevertheless, strip 6 is always integrated with plate 1, i.e. it must be formed on the plate or it must be factory-fitted.

In known designs according to the above-mentioned W094/26999 and W099/66151, the width of strip 6 can be approx. 30 mm and the thickness approx. 0.5 mm.

A similar, but shorter, strip 6' is arranged along one short side 5a of plate 1. The part of the strip 6 that protrudes beyond the connection plane VP is formed with a locking element 8 that protrudes along the entire strip 6. The locking element 8 has in its lower part an operative locking surface 10 which is directed towards the coupling plane VP and which has a height of, e.g. 0.5 mm. During laying, this locking surface 10 cooperates with a locking groove 14 which is made on the underside 3 of the locking edge part 4b of the opposite long side of an adjacent plate 1'. The strip 6' along the short side is provided with a corresponding locking element 8', and the locking edge part 5b of the opposite short side has a corresponding locking groove 14'. The edge of the locking grooves 14, 14' which faces away from the locking plane VP forms an operative locking surface 10' for cooperation with the operative locking surface 10 of the locking element.

For mechanical connection of long sides and also short sides also in the vertical direction (direction Dl in Fig. 1c), plate 1 is also formed along its one long side (locking edge part 4a) and its one short side (locking edge part 5a) with a laterally open hollow or tongue groove 16. This is bounded upwards by an upper cutout at the locking edge part 4a, 5a, and downwards by the respective strips 6, 6'. At the opposite edge parts 4b, 5b, there is an upper hollow 18 which delimits a locking tongue 20 which cooperates with the hollow or tongue groove 16 (see fig. 2a). Figures 1a-1c show how two long sides 4a, 4b of two such plates 1, 1' on a base U can be connected by downward angling by turning about a center C near the intersection of the surface plane HP and the connection plane VP, while the plates are mainly kept in contact together. Figures 2a-2c show how the short sides 5a, 5b of the plates 1, 1' can be connected together by clicking. The long sides 4a, 4b can be connected using both methods, while the connection of the short sides 5a, 5b - after laying the first row of floorboards - is usually only carried out by clicking after the long sides 4a, 4b have first been connected.

Since a new plate 1' and a previously laid plate 1 are to be connected along their edge parts 4a, 4b of the long side, according to Figures 1 to 1c, edge part 4b of the long side of the new plate 1' is pressed against edge part 4a of the long side of the previously laid plate 1 according to fig. la, so that the locking tongue 20 is brought into the hollow or tongue groove 16. The plate 1' is then angled down towards the subfloor U according to fig. lb. The locking tongue 20 goes completely into the hollow or tongue groove 16, while the locking element 8 of the strip is simultaneously clicked into the locking groove 14. During this downward angling, the upper part 9 of the locking element can be operative and effect steering of the new plate 1' against the previously laid plate 1 .

In their coupled position according to fig. 1c, the plates 1, 1' are absolutely locked in the D1 direction and also in the D2 direction along their edge parts 4a, 4b of the long sides, but the plates 1, 1' can be displaced relative to each other in the longitudinal direction by the links along the long sides (ie direction D3 ).

Figures 2a-2c show how the edge parts 5a and 5b of the short sides of the plates 1, 1' can be mechanically connected in the D1, and also in the D2 direction by the new plate 1' being displaced mainly horizontally towards the previously laid plate 1. This can particularly is carried out after the long side of the new plate 1' has been connected, by inward angling, according to fig. la-lc, with a previously laid plate 1 in an adjacent row. In the first step in fig. 2a bevelled surfaces of the hollow 16 and the locking tongue 20 interact so that the strip 6' is forced downwards as a direct consequence of the edge parts 5a, 5b of the short sides. During the final production, 6' clicks up as the locking element 8' enters the locking groove 14', so that the operative locking surfaces 10, 10' on the locking element 8' and in the locking groove 14' engage each other.

By repeating the operations depicted in figures la-c and 2a-c, the entire floor can be laid without glue and along all connecting edges. Thus, known floorboards of the above-mentioned type can be connected mechanically by first, as a rule, being angled downwards on the long side and by the short sides, the long side having been locked, being clicked together by horizontal displacement of the new board 1' along the long side of the former laid plate 1 (direction D3). The plates 1, 1' can, without destroying the connection, be taken up again in the opposite order of laying, and can then be laid once more. Parts of these laying principles are also used in connection with the present invention.

In order to function optimally, and to enable easy laying and removal, the known plates, after being connected along their long sides, should be able to occupy a position where there is a possibility of a small gap between the operative locking surface 10 of the locking element and the operative locking surface 10' of the locking groove 14. Nevertheless, no space is needed in the actual end-piece connection between the plates in the connection plane VP near the top side of the plates, i.e. in the surface plane HP). In order for such a position to be taken, it may be necessary to press one plate against the other. A more detailed description of this space can be found in WO94/26999. Such a space can be in the range of 0.01-0.05 mm between the operative locking surfaces 10, 10' as the long sides of adjacent plates are pressed against each other. This gap enables the locking element 8 to enter and exit the locking groove 14, 14'. Nevertheless, as mentioned, no space is needed in the connection between the plates, where the surface plane HP and the connection plane VP cross at the upper side of the floor plates.

The coupling system enables displacement along the coupling edge in the locked position after coupling an optional side. Therefore, the laying can be carried out in many different ways, all of which are variations of the 3 basic methods: angling the long side, and clicking the short side. Clicking long side, clicking short side.

Angle of short side, upward angle of two plates,

displacement of the new plate along the short side edge of the previous plate, and finally, downward angling of two plates.

The most common and safest laying method is that the long side is first angled downwards and locked against another floor slab. A shift is then carried out in the locked position towards the short side of a third floor plate, so that the short side can be clicked in. Laying can also be done by clicking one side, long or short side, together with another plate. Then a displacement is carried out in the locked position until the other side clicks together with a third plate. These types of methods require at least one page to be clicked. However, the laying can be carried out without the click function. The third alternative is that the short side of a first plate is first angled inwards towards the short side of another plate, which is already connected on its long side with a third plate. After this connection, the first and second plates are angled slightly upwards. The first plate is displaced in the upwardly angled position along its short side until the upper connecting edges of the first and third plates are in contact with each other, after which the two plates together are angled downwards.

The above-described floorboard and its locking system have been successful on the market for laminate floors that have a thickness of approx. 7 mm and an aluminum strip 6 with a thickness of approx. 0.6 mm. Correspondingly, commercial designs of the floorboards according to WO 9966151, as shown in figures 4a and 4b, have been successful. However, it has been found that this technique is not particularly suitable for floorboards made of wood fiber-based material, especially solid wood material or glued laminated wood material, to form parquet floors. One reason why this known technique is not suitable for this type of product is the large amount of material waste that occurs due to the machining of the edge parts to form a tongue groove of the required depth.

To partially address this problem, it would have been possible to apply the technique shown in figures 5a and 5b of the accompanying drawings, and which is described and shown in DE-A-3343601, i.e. it would have been possible to form both connecting edge parts of separate elements attached to the edges of the long sides. This technique also results in high costs with aluminum parts and with the considerable machining required. Moreover, it is difficult to attach the sectional elements along the edges in a cost-effective manner. However, the geometry shown does not allow connection and disconnection without considerable leeway at resp. downward and upward angling, since the components do not come apart during these movements if they are made with a tight fit (see fig 5b).

Another known design of floor plates with a mechanical locking system is shown in Figures 6a-d of the accompanying drawings and is described and illustrated in CA-A-0991373. As this mechanical locking system is used, all forces which try to pull the long sides of the plates apart are received by the locking element at the outer end of the strip (see fig. 6a). When the floor is laid or removed, the material must be flexible to enable the tongue to be released by rotation around two centers at the same time. A tight fit between all surfaces makes rational manufacturing and shifting in a locked position impossible. Short side 6c has no horizontal lock. However, this type of mechanical lock causes a large amount of material waste, due to the design of the large locking elements.

A further known design of mechanical locking systems for plates is described in GB-A-1430429 and figures 7a-7b of the accompanying drawings. This system is basically a tongue and groove coupler which can be fitted with an additional retaining hook on a lip which projects on one side of the tongue groove, and which has a corresponding retaining groove formed on the upper side of the tongue. The system requires a lot of elasticity of the lip which is arranged with the hook, and disconnection cannot be carried out without destroying the connecting edges. A tight fit makes production difficult, and the shape of the coupling causes a large amount of material waste.

Another known design for mechanical locking systems for floor slabs is described in DE-A-4242530. Such a locking system is also shown in Figures 8a-b in the accompanying drawings. This known locking system has several disadvantages. Not only does it provide a large amount of material waste during manufacture, it is also difficult to manufacture efficiently if high quality joints in a high quality floor are desired. The incised groove which forms the tongue groove can only be made by using a milling cutter with a shaft end, which is moved along the coupling edge. It is therefore not possible to use large disc-shaped cutting tools to machine the plate from the side edge.

For mechanical connection of different types of boards, especially floor boards, there are many proposals where the amount of material waste is small, and where production can be done in an efficient way, also using wood fibers and wood-based board materials. Thus, W09627721 (figures 9a-b in the accompanying drawings) and JP 3169967 (figures 10a-b in the accompanying drawings) describe two types of click couplings which give a small amount of loss, but which have the disadvantage that they do not enable disconnection of the floor plates when angled upwards. These coupling systems can be made efficiently using large disk-shaped cutting tools, but they have the serious disadvantage that disassembly by upward angling would cause such extensive damage to the locking system that the plates could not be re-inserted by mechanical locking.

Another known system is described in DE-A-1212275 and is shown in Figures lla-b in the accompanying drawings. This known system is suitable for sports floors of plastic material, and cannot be produced using large disc-shaped cutting tools to form the sharp incised groove. Also this known system cannot be disconnected by upward angling without the material having to have such great elasticity that the upper and lower lips around the incised groove are deformed to a great extent as they are pulled apart. This type of connection is therefore not suitable for floorboards that are based on wood fiber-based material, if high-quality connections are desired.

Tongue and groove couplings with an inclined groove and tongue have also been proposed in US-A-1124228. The type of connection depicted in figures 12c-d of the accompanying drawings enables a new plate to be fitted by pressing it down over the slanted upwards tongue of the previously laid plate. To fasten the newly laid board, nails are used which are driven diagonally down through the board over the slanted upwards tongue. In the design according to figures 12a-b, this technique cannot be used, since a finger joint is used. This technique certainly provides a small amount of material waste, but is not at all suitable if a floating floor is to be made, with individual floor plates that, without damage, should be installed and disconnected in an easy way and that have high-quality connections.

DE-A-3041781 describes and shows a locking system for connecting plates, in particular for making roller skating and bowling lanes of plastic material. Such a connection system is also shown in Figures 13a-d in the accompanying drawings. This system comprises an incised longitudinal groove along one edge of the plate and a projecting upwardly bent tongue along the opposite edge of the plate. In cross-section, the incised groove has a first part which is delimited by parallel surface parts and is parallel to the main plane of the plate, and a second internal part which is trapezoidal or semi-trapezoidal (Figures 13a-b and Figures 13c-d), respectively, in the accompanying drawings. In cross-section, the tongue has two plane-parallel parts angled relative to each other, where the part closest to the center of the plate is parallel to the main plane of the plate and where the outer free part is angled in an upward direction according to the corresponding surface part within the trapezoidal part of the incised groove.

The design of the tongue and groove, as well as the edge parts of the plate, is such that when two such plates are mechanically connected, engagement is achieved between, on the one hand, the surface parts of the tongue and corresponding surface parts of incised grooves along the entire upper side and outer end of the tongue as well as along the underside of the inner plane-parallel part of the tongue and, on the other hand, between the edge surfaces of the coupled plates above and below the tongue and the groove, respectively. As a new plate is to be connected with a previously laid plate, the new plate is angled upwards at a suitable angle for bringing the angled outer part of the tongue into the outer plane-parallel part of the groove in the previously laid plate. The tongue is then brought into the groove while the new plate is angled downwards. Because of. the angular shape of the tongue requires a large clearance in the first part of the groove to enable this bringing in and inward angulation to be carried out. Alternatively, a large degree of elasticity of the floor material is required, which according to the document should consist of plastic material. In the laid coupled position there is engagement between the main part of the surfaces of the tongue and the incised groove, except below the upwardly angled outer part of the tongue.

A serious disadvantage of the mechanical locking system according to DE-A-304781 is that it is difficult to manufacture. As a production method, it is proposed to use a mushroom-shaped shank cutter with an outer part that generates the inner part of the tongue groove with trapezoidal cross-sections. Such a production method is not particularly rational and, moreover, it causes major tolerance problems if the production method were to be used for the production of floor boards or other boards of wood material to form wall panels or parquet floor boards with high-quality joints.

As mentioned above, a disadvantage of this known mechanical locking system is that bringing the angled tongue into the groove requires a considerable clearance between the tongue and the groove (see Fig. 5 in DE-A-3041781 and Fig. 13 b in the accompanying drawings) so that downward angling can take place, if there is not a considerable degree of elasticity in the plate material. Moreover, such downward angling cannot be carried out while the new plate and the previously laid plate are brought together in such a way that they touch each other near the upper edge of the plates above the tongue, and the groove respectively, so that the center of rotation of the downward angling movement is positioned at this point .

A further disadvantage of this known mechanical locking system according to DE-A-3041781 in connection with rather thick boards of wooden material is that displacement of the new board along the previously laid board in a laid or partially raised position is made much more difficult by the boards engaging in each other along large surface sections. Although the machining of wooden boards or boards based on wood fibers would be very accurate, these surface parts are not very smooth for natural reasons, but have protruding fibers, which significantly increase friction. When laying parquet floors etc., long boards (often 2-2.4 m long and 0.2-0.4 wide boards) and mostly natural materials are involved. This type of long plates twists and will therefore often deviate from a totally flat shape (they have a "banana" shape). In these cases, it will be even more difficult to move a newly laid plate along a previously laid plate, if a mechanical interlocking of the plates is also desired on the short side.

A further disadvantage of the mechanical locking system according to DE-A-3041781 is that it does not fit well in connection with high-quality floors which are made of wood materials or wood fiber-based materials and which therefore require a tight fit in the vertical direction between the tongue and the groove to prevent squeaking.

WO 97/47834 describes floor plates with different types of mechanical locking systems. The locking systems intended to interlock the long sides of the plates (Figures 2-4, 11 and 22-25 of the document) are designed to be assembled and disengaged by a connecting and angling movement, while most of those intended to interlock the short sides of the plates (Figures 5-10) are designed to connect to each other by being pushed together for connection by means of a click connection, but these locking systems on the short sides of the plates cannot be disengaged without being broken, or at worst damaged .

Some of the plates described in WO 97/47834 and which have been designed to engage and disengage with an angular movement (Figures 2-4 of WO 97/47834 and Figures 14a-c of the accompanying drawings), have on their one edge a groove and a strip projecting below the track and projecting past a joint plane where the upper sides of joined plates meet. The strip is designed to cooperate with a generally complementary shaped part on the opposite edge of the plate, so that two corresponding plates can be connected. A common feature of these floor plates is that the upper side of the tongue of the plates and the corresponding upper boundary surfaces of the groove are flat and parallel to the upper side or surface of the floor plates. The connection of the plates to prevent them from being pulled apart transversely by the connecting plane, is achieved exclusively by means of the locking surfaces on the one hand on the underside of the tongue, and, on the other hand, on the upper side of the lower lip or strip below the groove. These locking systems also have the disadvantage that they require a strip part that projects past the coupling plane, which causes material waste also within the coupling edge part where the groove is formed.

WO 97/47834 also describes mechanical coupling systems comprising a circular arc-shaped tongue and a correspondingly shaped groove in the opposite side edge of the floor plate (cf. figures 14d-14e in the accompanying drawings). As such locking systems are connected, the tip of the tongue is brought towards the opening of the curved groove, after which downward angling is started. During this downward angulation, there is a large surface contact between all arcuate surfaces of the tongue and groove. If this type of connection system were to be used for long boards made of wood or wood-based materials, it would be very difficult to achieve a smooth and simple joining. Also, the friction between the arcuate surfaces and between the tip of the tongue and the bottom of the groove would require significant forces to move one plate along another plate in their coupled state. This known technique is certainly better than that described in the above-mentioned DE-A-3041781, but it has many disadvantages of that technique.

US-A-2740167 (see also figures 15a-b, in the accompanying drawings) describes parquet boards or squares which are made of wood and which on their opposite edges are formed with edge parts which are hooked into each other by laying several parquet squares in a row. One edge part has a downward-pointing notch, and the opposite edge part has an upward-pointing notch. In order to enable the introduction of a new parquet board under a previously laid parquet board, the underside of the upward-pointing notch is cut obliquely. The parquet boards that are connected with a vertical connection plane are exclusively fixed in the horizontal direction transverse to the connection plane. In order to secure the boards also perpendicular to the upper side of the parquet boards, a layer of glue is used which is applied in advance to the base on which the parquet floor is to be laid. A previously laid parquet board can therefore only be lifted again before the adhesive layer has set. In practice, this parquet floor is therefore permanently secured to the base after laying.

CA-A-22527 91 shows and describes floorboards which are

shaped with a specially designed groove along one long side and a complementary shaped tongue along the other long side. As shown in the description, and also in figures 16a-b in the accompanying drawings, the tongue and groove are rounded and angled obliquely upwards to enable connection of one plate with another by placing the new plate close to the laid plate and then lifting and they are angled at the same time, after which the track is drawn down the slanting upward tongue while simultaneously bringing together and angling downwards. Since the tongue and groove are complementary formed, it is difficult to connect, and in addition, again to pull adjacent floorboards apart. A deviation from the planar shape, i.e. the fact that there is a "banana shape", results in a further obstacle to the connection of two such plates. The risk of damage to the tongue is therefore great, and the design also causes large frictional forces between the surfaces of the tongue and the groove.

US-A-5797237 comprises a click-lock system for connecting parquet boards. In the accompanying drawings, fig. 17a a section through two connected plates, while fig. 17b shows that such a known floor plate cannot be disconnected by angling the plate upwards relative to the remaining horizontal floor plate. Instead, as shown in fig. 4b in the patent description, both the plate to be removed and the plate to which it is connected and which is to remain, must be lifted up to pull the tongue out of the groove. The system is very similar to that described in the above-mentioned US-A-2740167 (figures 15a-b in the accompanying drawings) but with the difference that a short lower lip is formed below the upper hook-shaped protrusion or lip. However, this short lower lip has no connecting effect since there is a gap between the underside of the tongue and the upper side of this short lip as two plates are joined. Moreover, this space is necessary for the disconnection method as shown in fig. 17c. Certainly the coupling system is claimed to be a click coupling, but probably the laid plate is angled slightly upwards to get the tongue under the hook-shaped lip of this plate. This mechanical locking system can, as also shown in the patent description, be produced using large disc-shaped cutting tools. There are no incised grooves, whose lower and upper lips bump up against the inserted tongue and lock it both vertically and horizontally, in this locking system. Therefore, the groove has a greater vertical protrusion than the corresponding parts of the tongue. The laid floor will therefore be able to move downwards and away from the base, which will cause creaking in the joints and unacceptable vertical displacements. Because of. the insufficient locking, a high-quality coupling cannot be achieved either.

FR-A-2675174 describes a mechanical coupling system for ceramic tiles having complementary formed opposing edge portions where separate spring clips are used which are mounted at a distance from each other and which are shaped to engage a protrusion on the edge portion of an adjacent tile. The locking system is not designed for disconnection when turning, which is clear from fig. 10a, and especially fig. 18b in the accompanying drawings.

Fig. 19a and 19b show floor plates which are shaped according to JP 7180333 and are produced by extrusion of metal material. After installation, it is practically impossible to disconnect such floor plates due to the connection geometry, which appears in fig. 19b.

Finally, figures 20a and 20b show another known connection system which is described in GB-A-2117813 and which is intended for large insulated wall panels. This system is very similar to the above-mentioned system according to CA-A-2252791 and the system from WO97/47834 as shown in Figures 14d and 14e in the accompanying drawings. The system suffers from the same disadvantages as these latter two systems and is not suitable for the efficient production of floorboards based on wood material or wood fiber material, especially if high-quality connections in a high-quality floor are desired. The construction according to this GB publication uses metal sections as connecting elements and cannot be disconnected when angled upwards.

Other known systems are described in, e.g., DE20013380U1, JP2000179137A, DE3041781, DE19925248, DE20001225, EP0623724, EP0976889, and EP1045083.

WO0201018 further discusses locking systems, and is not relevant with respect to the scope of the invention.

As can be seen from the above, known systems have both disadvantages and advantages. Nevertheless, no locking system is suitable for the rational production of floorboards with a locking system that is optimal in relation to production technique, wastage of materials, laying and removal function, and which can also be used for floors that must have high quality, strength and functionality in the laid state.

One purpose of the present invention is to satisfy this need and to produce such an optimal floor system and such optimal floor plates. Further objects of the invention are clear from what is described above, as well as from the following description.

Summary of the invention

A floor plate and a re-openable locking system therefor comprising an incised groove on one long side of the floor plate and a projecting tongue on the opposite long side of the floor plate. The incised groove has a corresponding upwardly directed inner locking surface at a distance from its tip. The tongue and groove are formed to join and pull apart with a pivoting motion centered near the intersection of the surface planes and the common joining plane of two adjacent floor plates. The notch in the groove of such a locking system is made with disk-shaped cutting tools, the axes of rotation of which are angled relative to each other to form first an inner part of the notch part of the groove and then a locking surface, arranged closer to the opening of the groove. A method of laying a floor of such boards includes the steps of laying a new board adjacent to a previously laid board, moving the tongue of the new board into the opening of the incised groove of the previously laid board, angling the new board upward under simultaneously insertion of the tongue into the incised groove, and at the same time downward angling of the new plate to the final position.

However, what characterizes the floor system and the floor slab, according to the invention, is described in the main requirements. The sub-claims define particularly preferred embodiments according to the invention. Further advantages and characteristics of the invention also appear from the following description.

Before specific and preferred embodiments of the invention shall be described with reference to the accompanying drawings, the basic concept of the invention and the strength and functional requirements shall be described.

The invention is applicable to rectangular floor slabs having a first pair of parallel sides and a second pair of parallel sides. To simplify the description, the first pair is referred to as long sides and the second pair as short sides. It should nevertheless be pointed out that the invention is also applicable to plates which may be square.

High connection quality

High connection quality means a tight fit in the locked position between the floorboards, both vertically and horizontally. It should be possible to connect the floorboards without particularly large visible cracks or differences in height between the connecting edges in the unloaded and also in the normally loaded state. In a high-quality floor, joint cracks and height differences should not be greater than 0.2 and 0.1 mm.

Downward angling with rotation at the coupling edge and steering

As will be clear from the following description, it must be possible to lock when angled downwards on at least one side, preferably the long side. The downward angle must be possible to perform with a rotation around a center near the intersection between the surface planes of the floor slabs and the connection plane to be made, i.e. near the upper connection edges of the slabs as they come into contact with each other. Otherwise, it is not possible to create a connection that in the locked position has tight connection edges.

It should be possible to end the rotation in a horizontal position, in which the floor plates are locked vertically without play, since a play can cause unwanted differences in levels between the connecting edges. Inward angling should also be carried out in a way that at the same time steers the floorboards towards each other with tight connecting edges and which corrects possible "banana shape" (i.e. deviation from a straight flat shape of the floorboard). The locking element and the locking track should have control means that cooperate with each other during inward angling. The downward angle should be carried out with great safety without the plates getting stuck and pinching each other to also cause a risk of the locking system being destroyed.

Upward angling around the connecting edge

It should be possible to angle the long side upwards so that the floorboards can be released. Since the plates in the initial position are connected with tight connecting edges, this upward angling must therefore also be possible with upper connecting edges in contact with each other and with rotation at the connecting edge. This possibility of upward angling is not only very important when floor slabs are changed, or when a floor is moved. Many floorboards are tested, or incorrectly laid adjacent to doors, corners etc. during installation. It is a serious disadvantage if the floor plates cannot be easily disconnected without destroying the connection system. Nor is it always the case that a plate that can be angled inwards can also be angled outwards again. In connection with the downward angling, a slight downward bending of the strip usually occurs, so that the locking element is bent backwards and downwards, and opens. If the connection system is not shaped with suitable angles and radii, the plate can be locked after laying in such a way that disconnection is not possible. After the connection of the long side has been opened by angling upwards, the short side can usually be pulled out along the connecting edge, but it is advantageous if the short side can also be opened by angling upwards. This is particularly advantageous as the plates are long, e.g. 2.4 metres, which makes it difficult to pull out card sides. The upward angling should be carried out with great safety without the plates being clamped and pinching each other, thus causing the risk of the locking system being destroyed.

Clicking in

It must be possible to lock the card sides by clicking horizontally. This requires parts of the coupling system to be flexible and bendable. Even if inward angling of long sides is much easier and faster than clicking in, it is an advantage if the long sides can also be clicked in, since certain laying operations, e.g. around doors, requires the panels to be connected horizontally.

Cost of material for long and short sides

If the floor slab e.g. is 1.2x0.2 m, each m2 of the floor surface will have approx. 6 times more long-side links than short-side links. A large part of material waste and expensive coupling materials is therefore less important on the short side than on the long side.

Horizontal strength

In order to achieve high strength, the locking element must usually have a high locking angle, so that the locking element does not click out. The locking element must be high and wide so that it does not break as it is exposed to high tensile loads as the floor shrinks in winter as a result of the relatively low humidity at this time of the year. This also applies to the material closest to the locking groove in the second plate. The connection on the short side should have higher strength than the connection on the long side, since the tensile load during shrinkage in winter is spread over a shorter connection length along the short side than along the long side.

Vertical strength

It should be possible to keep the plates even as they are subjected to vertical loads. Furthermore, movement in the coupling should be avoided since surfaces exposed to pressure move relative to each other, e.g. upper coupling edges, can cause creaking.

Displaceability

In order to enable locking of all four sides, it must be possible for a newly laid plate to be moved in a locked position along a previously laid plate. This should be done using a reasonable amount of force, e.g. by compression using a brick and hammer, without destroying the connection edges and without the connection system having to be formed with visible gaps horizontally and vertically. Displaceability is more important on the long side than on the short side since the friction is significantly greater there due to a longer link.

Production

It should be possible to manufacture the coupling system in a rational way using large rotary cutting tools that have extremely good accuracy and capacity.

Measurement

Good functionality, production tolerance and quality require that the connection profile can be measured and checked continuously. The critical parts in a mechanical coupling system should be designed in such a way that production and measurement are made possible. It should be possible to manufacture them with tolerances of a few hundredths of a millimetre, and therefore it should be possible to measure them with great accuracy, e.g. in a so-called profile projector (profile projector). If the coupling system is produced with linear cutting machining, the coupling system will, apart from certain production tolerances, have the same profile over the entire edge part. Therefore, the connection system can be measured with great accuracy by cutting out some samples by sawing from the floorboards and measuring them in the profile projector or a measuring microscope. Rational production requires that the connection system can also be measured quickly and easily without destructive methods, e.g. using kali-bre. This is made possible if there are as few critical parts in the locking system as possible.

Optimization of the long and short side

In order for a floorboard to be produced optimally with minimal costs, the long and short side must be optimized with regard to their different properties as stated above. For example, the long side must be optimized for downward angling, upward angling, positioning and displaceability, while the short side must be optimized for click-in and high strength. An optimally designed floor slab should therefore have different connection systems on the long and short sides.

Possibility to move the connecting edge transversely Wood-based floorboards and floorboards in general that contain wood fibers swell and shrink as the relative humidity changes. Swelling and shrinkage mostly start from the top, and the surface layers can therefore move to a greater extent than the core, i.e. the part from which the connecting edge is formed. To prevent the upper joint edges from raising or crushing in the event of severe swelling, or from joint cracking as it dries, the joint system should be designed to allow movement that compensates for swelling and shrinkage.

Disadvantages of known systems

Figures 4a and 4b show known systems of the type Alloc® original and Alloc®Home with a protruding strip that can be angled and clicked together.

Known coupling systems according to figures 9-16 can produce a mechanical coupling with less waste than mechanical locking systems with a protruding and machined strip. However, none of them satisfy the above-mentioned requirements and solve none of the problems which the present inventions aim to solve.

The click connectors according to Figures 7, 9, 10, 11, 12, 18 and 19 cannot be locked or opened by a turning movement around the upper part of the coupling edge, and the connectors according to Figures 8, 11, 19 cannot be produced rationally by machining plate materials with a rotary cutting tools that have a large tool diameter.

Floor boards according to figures 12a-b cannot be angled or clicked, but must first be brought in by pressing parallel to the connecting edge. The link according to figures 12c-d cannot be clicked. It can possibly be angled inward, but in that case it must be produced with too large a gap in the coupling system. The strength in the vertical direction is low since the upper and lower engaging surfaces are parallel. It is also difficult to produce and displace the coupling in the locked position, since it does not include any free surfaces. In addition, nailing to the base is suggested using nails that are driven diagonally into the floorboard above the tongue and directed diagonally upwards.

The coupling system according to figures 6c-d, 15a-b and 17a-b are examples of couplings which have no vertical lock, i.e. which allow movements perpendicular to the upper side of the plates.

The inwardly angled coupling according to Figures 14d-e has a number of disadvantages because it is manufactured and constructed according to the principle that it should have a tight fit and that the upper and lower parts of the tongue and groove follow circular arcs centered at the upper coupling edge , i.e. at the intersection between the coupling plane and the surface plane. This coupling does not have the necessary control parts, and the coupling is difficult to angle together as it has an incorrect design, and too large coupling surfaces. As a result, it pinches and has the so-called drawer effect during inward angling. The reinforcement in the horizontal direction is too low, which depends on a low upper locking angle and too little angular difference between the upper and lower engaging surfaces. Also, the front and upper up-angled portion of the tongue groove is too small to withstand the forces needed for a high-quality coupling system. The excessively large contact surfaces between the tongue and the groove, the absence of the necessary free surfaces without contact, and the requirement for a tight fit throughout the coupling make lateral displacement of the floor plate along the coupling edge significantly more difficult, and also makes rational production with the possibility of achieving good tolerances difficult . Nor can it be clicked together horizontally.

The connecting system according to figures 16a-b has a design that does not allow it to be angled together without a significant degree of material deformation, which is difficult to achieve in ordinary sheet materials suitable for flooring. Also in this case, all parts of the tongue and groove are in contact with each other. This makes lateral displacement of a plate in the locked position difficult or impossible. Nor is rational machining possible due to the fact that all surfaces are in contact with each other. Clicking cannot be performed either.

The coupling system according to Figures 6a-b cannot be angled together since it is designed to move around two rotating centers at the same time. It has no horizontal lock in the tongue groove. All surfaces are in contact with each other with a tight fit. In practice, the coupling system cannot be shifted and produced rationally. It is intended for use with a locking system shown in Figures 6c-d which is formed on the adjacent vertical set edge of the plate and which does not

needed laterally for moving connection purposes.

The coupling system according to Figures 8a-b has a tongue groove which cannot be produced with rotary cutting tools having a large tool diameter. It cannot click and is designed to prevent, upon initial tension and a tight fit adjacent to the outer vertical part of the strip, lateral displacement.

The coupling system according to Figures 5a-b comprises two aluminum parts. Production with rotary cutting tools with a large tool diameter to form the tongue groove is not feasible. The coupling system is shaped so that it is impossible to angle a new plate inward by keeping its upper coupling edge in contact with the upper coupling edge of the previously laid plate, so that the inward angling takes place around a center of rotation and the intersection between the coupling plane and the surface plane. To enable inward angling using this known system, it is necessary to have a significant gap that exceeds what is acceptable in common floor slabs where high quality aesthetic good joints are required. The coupling system according to figures 13a-d is difficult to manufacture since it requires contact over a large surface area of the outer part of the tongue and the tongue groove. This also makes lateral displacement in the closed position difficult. The coupling geometry makes upward angling around the upper coupling edge impossible.

The invention

The invention is based on a first understanding that by applying suitable production methods, mostly by machining and by using tools whose tool diameter significantly exceeds the thickness of the plate, it is possible and rational to form advanced forms of wood materials, wood-based plates and plastic materials, with high accuracy, and that this type of machining can be done inside a tongue groove at a distance from the coupling plane. Thus, the shape of the coupling system should be adapted to rational production, which must be able to be carried out with very small tolerances. However, it is not permitted that such an adaptation is made at the expense of other important properties of the floor plate and the locking system. The invention is also based on another understanding, which is based on the knowledge of the requirements that must be met by a mechanical coupling system for optimal function. This understanding has made it possible to satisfy these requirements in a way not previously known, namely by combining the design of the coupling system with, for example, specific angles, radii, gaps, free surfaces and relationships between different parts of the system, and optimal use of the material properties from the core or core, such as compression, elongation, expansion, tensile strength and compressive strength.

The invention is further based on a third understanding that it is possible to produce a coupling system with lower production costs, but at the same time that the function and strength can be retained or even, in some cases, improved by a combination of production technique, coupling design, material selection and optimization of long- and short pages.

The invention is based on a fourth understanding that the coupling system, the production technique and the measurement technique must be developed and adjusted so that the critical parts that require low tolerances are as few as possible and are designed to allow measurement and control in continuous production.

According to a first aspect of the invention, there is thus provided a floor system comprising a floor plate that is mechanically connectable at all four sides of the floor plates in a first vertical direction Dl, a second horizontal direction D2, and a third direction D3 perpendicular to the second horizontal direction, with corresponding sides of other floor slabs with identical locking systems.

The floorboards can have a disconnectable mechanical coupling system of a known type on two sides and which can be moved laterally into a locked position and locked by inward angling around the upper coupling edges or by horizontal clicking. The floorboards have a locking system according to the invention on the other two sides. The floorboards can also have a locking system according to the invention on all four sides.

Thus, at least two opposite sides of the floor slab have

a coupling system which is constructed according to the invention and which comprises a tongue and a tongue groove delimited by the upper and lower lips, where the tongue in its outer and upper part has an upwardly directed part and where the tongue groove in its inner and upper part has an incision. The upwardly directed part of the tongue, and the incision of the tongue groove in the upper lip, have locking surfaces which counteract and prevent horizontal separation in a direction D2 transverse to the coupling plane. The tongue and the tongue groove also have cooperating supporting surfaces which prevent vertical separation in a direction D2 parallel to the coupling plane. Such supporting surfaces can be present in at least the lower part of the tongue and on the lower lip of the tongue groove. In the upper part, the cooperating locking surfaces can function as upper supporting surfaces, but the lower lip of the tongue groove and the tongue can advantageously also have

separate upper supporting surfaces. The tongue, tongue groove, locking element and notch are designed so that they can be produced by machining using tools that have a larger tool diameter than the thickness of the floorboard. The tongue, with its upwardly directed portion, can be brought into the tongue groove and its notch by an inward angle with its center of rotation near the intersection of the coupling plane and the surface plane, and the tongue can also leave the tongue groove if the floor plate is rotated or angled upward with its upper coupling edge in contact with the upper coupling edge of an adjacent floor plate. For the purpose of simplifying the manufacture, measurement, inward angling, upward angling and lateral displacement in the longitudinal direction of the coupling and to counteract creaking and to reduce possible problems due to swelling/shrinkage of the floor material, the connection system is formed with surfaces that are not in contact with each other both during inward angling and in the locked position.

Several aspects of the invention are also applicable with the known systems without these aspects being combined with the preferred locking systems described here.

The invention also describes the basic principles that should be satisfied for a tongue and groove coupling which is to be angled inwards with the upper coupling edges in contact with each other, and which is to be clicked in with a minimum bending of the coupling components.

The invention also describes how material properties can be used to achieve strength and low costs in combination with angling and clicking as well as laying methods.

Various aspects of the invention will now be described in more detail with reference to the accompanying drawings showing various embodiments of the invention. The parts of the plate according to the invention which are equivalent to those of the known plate in figures 1-2, have always been given the same reference numbers.

Brief description of the drawings

Fig. la-c shows in three steps a downward angling method for mechanically connecting long sides to floorboards according to W094/26999. Fig. 2a-c shows in three steps a click-in method for mechanically connecting short sides to floorboards according to W094/26999. Fig. 3a-b shows a floor plate according to WO94/26999 set

from above and below, respectively.

Fig. 4a-b show two different designs of

floor slabs according to W099/66151.

Fig. 5a-5b show floor plates according to DE-A-3343601.

Fig. 6a-d show mechanical locking systems for respectively long and short sides, for floor slabs according to CA-A-0991373. Fig. 7a-b show a mechanical locking system according to GB-A-1430429.

Fig. 8a-b show plates according to DE-A-4242530.

Fig. 9a-b shows a click coupling according to WO 96/27721. Fig. 10a-b shows a click coupling according to JP 3169967. Fig. 11a-b shows a click coupling according to DE-A-1212275. Fig. 12a-d show different embodiments of locking systems based on tongue and groove according to US-A-1124228. Fig. 13a-d shows a mechanical coupling system for

sports floor according to DE-A-3041781.

Fig. 14a-e show one of the locking systems shown in

WO 97/47834. Fig. 15a-b show a parquet floor according to US-A-2740167. Fig. 16a-b shows a mechanical locking system for floor slabs

according to CA-A-2252791.

Fig. 17a-b show a click lock system for parquet floors according to US-A-5797237. Fig. 18a-b shows a connection system for ceramics

tiles according to FR-A-2675174.

Fig. 19a-b shows a connection system for floor plates which is described in JP 7180333 and which is made by extruding metal material. Fig. 20a-b shows a connection system for large walls panels according to GB-A-2117813. Fig. 21a-b schematically shows two parallel connecting edge parts of a first preferred embodiment of a floor plate according to the present invention. Fig. 22 schematically shows the basic principles of inward angling around upper coupling edges using the present invention. Fig. 23a-b schematically shows the production of a connecting edge of a floor plate according to the invention. Fig. 24a-b shows a production-specific variant of

the invention.

Fig. 25 shows a variant of the invention as well as click-in and upward angling in combination with bending of the lower lip. Fig. 26 shows a variant of the invention with a

short lip.

Fig. 27a-c shows a method for downward and

upward angle.

Fig. 28a-c show an alternative angling method.

Fig. 29A-b shows a click-in method.

Fig. 30 shows how the long sides of two plates are connected to the long side of a turntable, as the two plates are already connected to each other on the short sides. Fig. 31a-b shows two connected floor plates arranged with a combination connection according to the invention. Fig. 32a-d shows inward angling of the combined

coupling.

Fig. 33 shows an example of how a long side

can be shaped into a parquet floor.

Fig. 34 shows an example of how a short page

can be shaped into a parquet floor.

Fig. 35 shows a detailed example of how the connection system of the long side can be formed in a parquet floor. Fig. 36 shows an example of a floor plate according to the invention where the coupling system is constructed so that it can be angled by applying bending and compression in the coupling material. Fig. 37 shows a floor plate according to the invention. Fig. 38a-b shows a manufacturing method in 4 steps that uses a manufacturing method according to the invention. Fig. 39 shows a connection system which is suitable to

compensate for swelling and shrinkage of the surface layer of the floor slab.

Fig. 40 shows a variant of the invention with a

stiff tongue.

Fig. 41 shows a variant of the invention where the locking surfaces form upper contact surfaces. Fig. 42a-b shows a variant of the invention with long tongue as well as angulation and extension. Fig. 43a-c shows how the connection system should be are constructed to enable click-in. Fig. 44 shows engagement in the angled position. Fig. 45a-b shows a connection system according to the invention

with a flexible tongue.

Fig. 46a-b shows a coupling system according to the invention with a divided and flexible tongue. Fig. 47a-b shows a coupling system according to the invention with a lower lip which partly consists of a different material than the core. Fig. 48a-b shows a connection system that is used as a click connection in a floor plate that is locked on all four sides. Fig. 49 shows a connection system that can be used, eg, on the short side of a floor slab. Fig. 50 shows another example of a connection system that can be used, e.g. on the short side of a floor slab.

Fig. 51a-f shows a laying method.

Fig. 52a-b shows laying using a special

engineered tool.

Fig. 53 shows the connection of the short sides.

Fig. 54a-b shows the snapping of the short side.

Fig. 55 shows a variant of the invention with a flexible tongue which enables the short side to be clicked in. Fig. 56a-e show clicking in the outer corner part of

the short side.

Fig. 57a-e shows the snapping of the inner corner part of

the short side.

Detailed description of preferred designs

A first preferred embodiment of a floor plate 1, 1', which is arranged with a mechanical locking system according to the invention will now be described with reference to figures 21a and 21b. To simplify understanding, the connection system is shown schematically. It must be emphasized that a better effect can be achieved with other preferred embodiments which will be described below.

Figures 21a, 21b schematically show a section through a connection between a long side edge part 4a of a plate 1 and an opposite long side edge part 4b of another plate 1'.

The upper sides of the plates are mainly positioned in a common surface plane HP and the upper parts of connecting edge parts 4a, 4b engage each other in a vertical connecting plane VP. The mechanical locking system results in locking of the plates relative to each other, both in the vertical direction D1 and the horizontal direction D2 projecting perpendicular to the connection plane VP. During the laying of a floor with juxtaposed rows of plates, one plate (1') can however be displaced along the other plate (1) in a direction D3 (see fig. 3a) along the connection plane VP. Such a shift can, for example, be used to produce interlocking of the floorboards which lie in the same row.

In order to produce coupling of the two coupling edge parts perpendicular to the vertical plane VP, and parallel to the horizontal plane HP, the edges of the floor plate in a manner known per se have a tongue groove 36 in one edge part 24a of the floor plate in the coupling plane VP, and a tongue 38 formed in the second coupling edge part 4b which protrudes past the coupling plane VP.

In this embodiment, board 1 has a core, or core 30, of wood supporting a surface layer of wood 32 on its front side, and a balancing layer 34 on its back side. Plate 1 is square and also has a second mechanical locking system on the two parallel short sides. In some embodiments, this second locking system can have the same design as the locking system on the long sides, but the locking system on the short sides can also be constructed differently according to the invention, or be a previously known mechanical locking system.

As an illustrative, non-limiting example, the floor board can be the parquet type with a thickness of 15 mm, a length of 2.4 m, and a width of 0.2 m. However, the invention can be used for square parquet parts or boards of different sizes.

The core 30 can be of the lamellar type and consist of narrow wooden blocks of an inexpensive type of wood. Surface layer 32 can have a thickness of 3-4 mm and consist of a kind of decorative hard wood and can be lacquered. The balance layer 34 of the back can consist of a 2 mm thick veneer layer. In some cases, it may be advantageous to use different types of wood materials in different parts of the floorboard for optimal properties within the individual parts of the floorboard.

As mentioned above, the mechanical locking system according to the invention comprises a tongue groove 36 in one connecting edge part 4a of the floor plate, and a tongue 38 on the opposite connecting edge part 4b of the floor plate.

The tongue groove 36 is delimited by the upper and lower lips 39, 40 and has the form of an incised groove with an opening between the two lips 39, 40.

The various parts of the tongue groove 36 can best be seen in fig. 21b. The tongue groove is formed in the core, or core 30, and projects from the edge of the floorboard. Above the tongue groove there is an upper edge part or coupling edge surface 41 which projects up to the surface plane HP. Inside the opening of the tongue groove there is an upper engaging or supporting surface 43 which in this case is parallel to the surface plane HP. This engaging or supporting surface transitions into an inclined locking surface 43 which has a locking angle A with the horizontal plane HP. Inside the locking surface there is a surface part 4 6 which forms the upper boundary surfaces of the notched part 35 of the tongue groove. The tongue groove further has a bottom 48 which projects down to the lower lip 40. On the upper side of this lip there is a coupling or supporting surface 50. The outer end of the lower lip has a coupling edge surface 52, and in this case projects slightly past the connecting plane VP.

The shape of the tongue is also best seen in fig. 21b. The tongue is formed from the material of the core, or core 30, and projects beyond the connection plane VP as this connection edge part 4b is mechanically connected to the connection edge part 4a of an adjacent floor plate. Coupling edge part 4b also has an upper edge part or upper coupling edge surface 61 which projects along the coupling plane VP down to the root of the tongue 38. The upper side of the tongue root has an upper engaging or supporting surface 64 which in this case projects to an inclined locking surface 65 to an upwardly directed part 8 near the tip of the tongue. The locking surface 65 moves into a guide surface part 66 which ends in an upper surface 67 of the upwardly directed part 8 of the tongue. After the surface 67 follows an inclined edge which can function as a control surface 68. This projects to the tip 69 of the tongue. At the lower end of the tip 69 there is a further guide surface 70 projecting obliquely downwards to the lower edge of the tongue and an engaging or supporting surface 71. The supporting surface 71 acts to cooperate with the supporting surface 50 of the lower lip as two such floor plates are mechanically connected, so that their upper sides are positioned in the same surface plane HP and meet at a connecting plane VP, which is directed perpendicularly thereto, so that the upper connecting edge surface 41, 61 of the plates engage each other. The tongue has a lower coupling edge surface 72 which projects to the underside.

In this embodiment, there are separate engaging or supporting surfaces 43, 64 in the tongue groove, and on the tongue, respectively, which in the locked state engage with each other and interact with the lower supporting surfaces 50, 71 on the respective the lower lip and the tongue, to provide the locking in the direction Dl perpendicular to the surface plane HP. In other embodiments, which are described below, the locking surfaces 45, 65 are used both as locking surfaces to lock together in the direction D2 parallel to the surface plane HP, and as supporting surfaces to counteract movements in the direction D2 perpendicular to the surface plane. In the embodiment according to figures 21a and 2b, the locking surface 45, 65 and the engagement surfaces 43, 64 cooperate as upper supporting surfaces in the system.

As can be seen from the drawing, the tongue 38 projects beyond the coupling plane VP and has an upwardly directed portion 8 at its free outer end or tip 69. The tongue also has a locking surface 65 which is shaped to cooperate with the inner locking surface 45 in the tongue groove 36 to an adjacent floor slab in that two such floor slabs are mechanically connected, so that their front sides lie in the same surface plane HP and meet at a connection plane VP directed perpendicular to it.

As can be seen from fig. 21b, the tongue 38 has a surface part 52 between the locking surface 51 and the coupling plane VP. As two floor plates are connected together, surface part 52 engages in surface part 45 of the upper lip 8. To enable the introduction of the tongue into the cut groove by inward angling or snapping, the tongue, as depicted in figures 21a, 21b, can have a bevel 66 between the locking surface 65 and the surface part 57. Furthermore, a bevel 68 can be arranged between the surface part 57 and the tip 69 of the tongue. The beveled edge 66 can function as a guide part by having a lower angle of inclination to the surface plane than the angle of inclination A of the locking surfaces 43, 51.

The supporting surface 71 of the tongue is in this embodiment essentially parallel to the surface plane HP. The tongue has a bevel 70 between this supporting surface and the tip 69 of the tongue.

According to the invention, the lower lip 40 has a supporting surface 50 for cooperation with the corresponding supporting surface 71 of the tongue 36 at a distance from the inner part 47 of the incised groove. Since two floor plates are connected together, there is a connection both between the supporting surfaces 50, 71 and between the connecting or supporting surface 43 of the upper lip 39 and the corresponding connecting or supporting surface 64 of the tongue. In this way, locking of the plates in the direction Dl perpendicular to the surface surface plane HP is achieved.

According to the invention, at least the greater part of the inner part 47 of the incised groove, seen parallel to the surface plane HP, is arranged further away from the coupling plane VP than the outer end or tip 69 of the tongue 36. With this design, the manufacture is greatly simplified, and it is possible displacement of one floor slab relative to another along the connection plane.

Another important feature of a mechanical locking system according to the invention is that all parts of the parts of the lower lip 40 which are connected to lip 30, seen from point C where the surface plane HP and the connecting plane VP cross, are on the outside of a plane LP2. This plane is further away from point C than a locking plane LP1 which is parallel to the plane LP2 and which is tangent to the cooperating locking surfaces 45, 65 of the incised groove 36 and the tongue 38, where these locking surfaces are most inclined, relative to the surface plane HP. Because of. this design, the slotted groove, which will be described in more detail below, can be formed using large disc-shaped rotary cutting tools for machining the edge portions of the floorboards.

A further important feature of a locking system according to the present invention is that the upper and lower lips 39 and 40 and the tongue 38 of the connecting edge parts 4a, 4b are designed to enable the disconnection of two mechanically connected floor plates by turning one floor plate upwards relative to the other around a center of rotation near the intersection point C between the surface plane HP and the connecting plane VP, so that the tongue of this floor plate is pivoted out of the incised groove of the other floor plate.

In the design according to figures 21a, 21b, such a disconnection is made possible by a slight downward bending of the lower lip 40. In other more preferred embodiments of the invention, however, no downward bending of the lower lip is needed in connection with connecting and disconnecting the floor plates.

In the embodiment according to figures 21a, 21b, the connection of two floor plates according to the invention can be carried out in three different ways.

One way involves the plate 1' being placed on the base and pushed against the previously laid plate 1' until the narrow tip 69 of the tongue 38 has been introduced into the opening of the incised groove 36. Then the floor plate 1' is angled upwards,

so that the upper parts 41, 61 of the plates on both sides of the connecting plane VP come into contact with each other. While this contact is maintained, the plate is angled downwards by turning about the center of rotation C. The insertion takes place at the beveled edge 66 of the tongue which slides along the locking surface 45 of the upper lip 39, while the beveled edge 70 of the tongue 38 simultaneously slides against the outer edge of the upper side of the lower lip 40. The locking system can then be opened by angling the floor plate 1' over by turning around the center of rotation C near the intersection between the surface plane and the connection plane VP.

The second way of interlocking is provided by pushing the new plate with its connecting edge part 4a, which is provided with a tongue groove, against the connecting edge part 4b, which is provided with a tongue, of the previously laid plate. Next, the new plate is rotated upwards until contact has occurred between the upper parts 41, 61 of the plates near the intersection of the surface plane and the coupling plane, after which the plate is rotated downwards to bring the tongue and groove together, until the final locked position is achieved. According to the following description, the floor slabs can also be joined by moving one slab in an upwardly angled position towards the other.

A third way to provide connection of the floorboards in this embodiment of floorboards according to the invention, involves the new board 1' being shifted horizontally towards the previously laid board 1, so that the tongue 38 with its locking element or upwardly directed part 8 is brought into the tongue groove 36, where the lower flexible lip 40 is bent slightly downwards so that the locking element 8 can be clicked into the notched part 35 of the tongue groove. In this case too, disconnection takes place by angling upwards, as described above.

In connection with clicking in, a slight upward bending of the upper lip 39 can also take place, and in the same way a certain degree of compression of all parts in the groove 36 and the tongue 83 that are in contact with each other during clicking in can also take place . This enables click-in and can be used to form an optimal connection system.

To enable manufacture, inward angling, upward angling, snapping and displaceability in the closed position, and to minimize the risk of creaking, all surfaces that are non-operative to form a connection with tight upper connecting edges and to form the vertical and horizontal connection should , so as not to be in contact with each other in the closed position, and preferably also during locking and disconnection. This allows production without requiring high tolerances in these coupling parts and reduces friction during lateral displacement along the coupling edge. Examples of surfaces or parts of the coupling system that should not be in contact with each other in the locked position are 46-67, 48-69, 50-70 and 52-72.

The coupling system according to the preferred embodiment may consist of several combinations of materials. The upper lip 39 can be formed by a rigid and hard upper surface layer 32 and a softer lower part which is part of the core 30. The lower lip 40 can consist of the same soft upper part 30 and also a lower soft part 34 which can be a other kind of wood. The directions of the fibers in the three types of wood can vary. This can be used to provide a connection system that utilizes these material properties. According to the invention, the locking element is therefore located closer to the hard and rigid part, which is therefore only flexible and compressible to a limited extent, while the click function is provided in the softer lower and flexible part. It should be pointed out that the connection system can also be formed from a homogeneous floor slab.

Fig. 22 schematically shows the basic principles of inward angling around a point C (upper connecting edges) when using the present invention. Fig. 22 shows schematically how a locking system should be constructed to enable inward angling around the upper coupling edges. With this inward angulation, parts of the coupling system in the old fashion follow a circular arc with the center C near the intersection of the surface plane HP and the coupling plane VP. If a large gap between all parts of the coupling system is allowed, or if significant deformation during inward angling is possible, the tongue and groove can be formed in many different ways. If, on the other hand, the coupling system must have contact surfaces that prevent vertical and horizontal separation without any space between coupling or supporting surfaces, and if material deformation is not possible, the coupling system should be constructed according to the following principles.

The upper part of the coupling system is formed as follows. C1B is a circular arc which has its center C at the top of the upper connecting edges 41, 61, and which in this preferred embodiment crosses a contact point between the upper lip 39 and the upper part of the tongue 38 at point P2. All other contact points between P2, P3, P4 and P5 between the upper lip 39 and the upper part 8 of the tongue 38 and between this crossing point P2 and vertical plane VP, are positioned on or on the inside of this circular arc C1B, while all other contact points from P2 to Pl between the upper lip 39 and the upper part of the tongue 38 and between this crossing point P2 and the outer part of the tongue 38 are positioned on or outside this circular arc C1B. These conditions should be satisfied for all contact points. Regarding the contact point P5 with the circular arc CIA, it is the case that other contact points between Pl and P5 are positioned outside the circular arc CIA, and regarding the point Pl, all other contact points between Pl and P5 are positioned within the circular arc C1C.

The lower part of the coupling system is formed according to the corresponding principles. C2B is a circular arc which is concentric with the circular arc CIA and which in this preferred embodiment crosses a point of contact between the lower lip 40 and the lower part of the tongue 38 at point P7. All other contact points between P7, P8 and P9 between the lower lip 40 and the lower part of the tongue 38, and between this crossing point P7 and the vertical plane are positioned on or outside the circular arc C2B, and all other contact points between P6, P7 and between the lower lip 40 and the lower parts of the tongue 38 and between this crossing point P7 and the outer part of the tongue 38 is positioned on or within this circular arc C2B. The same applies to the contact point P6 with the circular arc C2A.

A coupling system constructed according to this preferred embodiment may have good inward angle characteristics. It can easily be combined with upper connecting or supporting surfaces 43, 64 which can be parallel to the horizontal plane HP and which can therefore provide excellent vertical locking.

Figures 23a, 23b show how a connection system according to figures 21a, 2b can be produced. Usually, according to known technique, the floor plate 1 is positioned with its surface 2 downwards on a ball bearing chain in a milling machine which guides the plate with extremely high accuracy past a number of milling cutters such as e.g. has a tool diameter of 80-300 mm and which can be set at any angle with the horizontal plane of the plate. However, to simplify understanding and comparison with the other figures, the floor slab is depicted with its surface plane HP pointing upwards. Fig. 23a shows how the first tool with tool position TP1 makes a traditional tongue groove. In that case, the tool acts on a tool angle TA1 which is 0°, i.e. parallel to

the horizontal plane. The axis of rotation RAI is perpendicular to HP. The notch is made by means of a second tool, where the position TP2 and the design of the tool are such that the notch 35 can be formed without the tool affecting the shape of the lower lip 40. In this case, the tool has an angle TA2 equal to the angle of the locking surface 45 in the notch 35. This manufacturing method is possible in that the locking surface LP1 is at such a distance from the coupling plane that the tool can be brought into the previously formed tongue groove. Therefore, the thickness can

the tool does not exceed the distance between the two planes LP1 and LP2, as described in connection with figures 21a and 21b. This production method is known technology and does not form part of the production method according to the present invention, which will be described below.

Figures 24a, 24b show another variant of the invention. This embodiment is characterized by the fact that the coupling system is completely formed according to the basic principle of inward angling around the upper coupling edges as described above. The locking surfaces 45, 65 and the lower supporting surfaces 50, 71 are in this embodiment flat, but they can have a different shape. Cl and C2 are two circular arcs with center C at the upper end of adjacent coupling edges 41, 61. The smaller circular arc Cl is tangent to the lower contact points closest to the vertical plane between the locking surfaces 45, 65 at point P4 which has the tangent TL1 corresponding to the locking plane LP1. The locking surfaces 45, 65 have the same angle as this tangent.

All contact points between the tongue 38 and the upper lip 39 which are positioned between the point P4 and the vertical plane VP satisfy the condition that they are positioned within or on the circular arc Cl, while all contact points which are positioned between P4 and the inner part 48 of

the tongue groove - in this embodiment only the locking surfaces 45, 65

- satisfies the condition that they are positioned on, or on the outside of, Cl. The corresponding prerequisites are satisfied for the contact surfaces between the lower

lip 40 and tongue 38. All contact points between the tongue 38 and the upper lip 39 which are positioned between point P7 and the vertical plane VP - in this case only the lower supporting surfaces 50, 71 - are positioned on, or on the outside of, the circular arc C2, while all contact points positioned between point P7 and the inner part 48 of the tongue groove are positioned on or inside the circular arc C2. In this embodiment, there are no contact points between P7 and the inner part 48 of the tongue groove.

This design is characterized in particular by the fact that all contact surfaces between contact point P4 and the connection plane VP, in this case point P5, and the inner part 48 of the tongue groove, are positioned respectively. inside and outside, the circular arc Cl, and therefore not on the circular arc Cl. The same applies to contact point P7, where all contact points between P7 and the vertical plane VP, in this case the point P8, and the inner part 48 of the tongue groove, are positioned respectively. outside and inside the circular arc C2 and therefore not on the circular arc C2. As can be seen from the part indicated by dashed lines in fig. 24a, the coupling system, if this condition is satisfied, can be constructed so that inward angulation can take place at intervals during most of the entire angular movement, which can be terminated by the plates being locked with a tight fit or with a press fit when they have assumed the final horizontal position. Therefore, the invention enables a combination of inward angling and upward angling without resistance and a locking with high coupling quality. If the lower supporting surfaces 71, 50 are formed with a slightly smaller angle, a coupling system can be provided where only the two above-mentioned points P4 on the upper lip and P7 on the lower part of the tongue are contact points between the tongue groove 36 and the tongue 38 during the entire inward angulation, until final locking takes place, during which the entire upward angle until the plates can be released from each other. Locking with gaps or with only line contact is a great advantage, since the friction will be low, and since the plates can easily be angled inwards and upwards, without parts of the system getting stuck and pinching each other with a risk of destroying the coupling system. A press fit, especially in the vertical direction, is very important for strength. If there is a gap between the connecting or supporting surfaces, the plates, being subjected to tensile loading, will be pushed along the locking surfaces until the lower connecting or supporting surfaces have assumed a press-fit position. Therefore, a gap will result in both a coupling crack and a difference in level between the upper coupling edges. As an example, it can be mentioned that with a tight fit or press fit, high strength can be achieved, if the lock-over pieces have an angle of approx. 40° with the surface plane HP and if the lower connecting or supporting surfaces have an angle of approx. 15° to the surface plane HP.

The locking plane LP1 has in fig. 24a a locking angle A with the horizontal plane HP of approx. 39°, while the support plane TL2 along the supporting surfaces 50, 71 has a supporting angle VLA of approx. 14°. The angle difference between LPl and the support plane TL2 is 25°. A high locking angle and a large difference in angle between locking angle and support angle should be sought since this results in a large horizontal locking force. The locking surfaces and the supporting surfaces can be made curved, stepped, multi-angled, etc., but this makes manufacturing difficult. As mentioned above, the locking surfaces may also constitute upper support surfaces or be additions to separate upper support surfaces.

Even if the locking surfaces and the supporting surfaces have contact points that deviate slightly from these basic principles, they can be angled inward at their upper connecting edges if the connecting system is adapted so that its contact points or surfaces are small in relation to the floor thickness, and so that the properties of the plate material in terms of compression , extension and bending are used maximally in combination with very small spaces between the contact surfaces. This can be used to increase the locking angle and the difference in angle between locking angle and support angle.

The basic principle of inward angling therefore shows that the critical parts are the locking surfaces 45, 65 and the lower supporting surfaces 50, 71. It also shows that the degree of freedom is large regarding the construction of the other parts, e.g. the upper supporting surfaces 43, 64, the guide 44 of the locking groove, the guide 66 and the top surface 67 of the locking element 8, the inner parts 48, 49 of the tongue groove 36 and the lower lip 40, the guiding and the outer part 51 of the lower lip as well as outer/lower parts 69, 70 and 72 of the tongue. These should preferably deviate from the shape of the two circular arcs Cl and C2, and between all parts except the upper supporting surfaces 33, 64 there may be free spaces, so that these parts in the locked position, as well as during inward angling and upward angling , are not in contact with each other. This simplifies production significantly, since these parts can be formed without large tolerance requirements, and it contributes to safe inward and upward angling, and also to lower friction in connection with lateral displacement of connected plates along the connection plane VP (direction D3). By free space is meant coupling parts which have no functional significance in preventing vertical or horizontal displacement and displacement along the coupling edge in the locked position. Therefore, loose wood fibers and small deformable contact points should be considered equivalent to free surfaces.

Angulation around the upper coupling edge can, as mentioned above, be simplified if the coupling system is constructed so that there can be a small clearance between all the above-mentioned locking surfaces 45, 65 if the coupling edges of the plates are pressed together. The construction clearance also enables lateral displacement in the locked position, reduces the risk of creaking and gives a greater degree of freedom in manufacturing, allows inward angulation with locking surfaces that have a greater angle than the tangent LP1 and contributes to compensation for swelling of the upper coupling edges. The clearance gives considerably smaller coupling cracks at the upper side of the plates and considerably smaller vertical displacements than a clearance between the connecting or supporting surfaces would, especially due to that this leeway is small and also because the fact that a slip in the tensile loaded position will follow the angle of the lower supporting surface, i.e. an angle which is generally smaller than the locking angle. This minimal gap, if any, between the locking surfaces can be very small, e.g. only 0.01 mm. In the normal coupled position, the gap may be non-existent, i.e. 0. The coupling system may be designed so that a gap only occurs in maximum compression of the coupling edges of the plates. It was found that a larger leeway of approx. 0.05 mm will result in a very high coupling quality, since the coupling crack which should exist in the surface plane HP and which may occur in the tensile loaded position is barely visible.

It should be noted that the coupling system can be constructed without any clearance between the locking surfaces.

Space and material compression between the locking surfaces and bending of coupling parts at the locking surfaces can easily be measured indirectly by subjecting the coupling system to a tensile load, and by measuring the coupling crack at the upper coupling edges 41, 61 at a predetermined load that is less than the strength of the coupling system. By strength is meant that the coupling system is not destroyed or snaps out. A suitable tensile load is approx. 50% of the strength. As a non-limiting standard value, it can be mentioned that a long-side coupling should usually have a strength greater than 300 kg per running meter coupling. Short side links should have even greater strength. A parquet floor with a suitable connection system according to the invention can withstand a tensile load of 1000 kg per running meter connection. A high-quality coupling system should have a coupling crack at the upper coupling edges 41, 61 of approx. 0.1-0.2 mm, as it is subjected to a tensile load of approx. half of the maximum strength. The coupling gap should decrease as the load is removed. By varying the tensile load, the relationship between construction gaps and material deformation can be determined. In the case of lower tensile loads, the joint crack is largely a measure of the construction gap. In the case of a higher load, the coupling crack increases as a result of material deformation. The coupling system can also be constructed with built-in bias and a press fit between the locking surfaces and the supporting surfaces, so that the above-mentioned coupling crack is not visible in the case of the above-mentioned load.

The geometry of the coupling system, spaces between the lock-over tracks in combination with compression of the material around the upper coupling edges 41, 61 can also be measured by sawing the coupling transversely of the coupling edge. Since the coupling system is manufactured with linear machining, it will have the same profile along its entire coupling edge. The only exception is manufacturing tolerances in the form of lack of parallelism as a result of the fact that the plate can possibly be turned or shifted vertically or horizontally as it passes through different milling tools in the machine. Usually, however, the two samples from each link edge give a very reliable picture of what the link system looks like. After grinding the samples and cleaning them of loose fibers so that a sharp coupling profile can be seen, they can be analyzed according to coupling geometry, material compression, bending etc. The two coupling parts can e.g. is compressed using a force that is such that it does not destroy the coupling system, especially the upper coupling edges 41, 61. The gap between the locking surfaces and the coupling geometry can then be measured in a measuring microscope with an accuracy of 0.01 mm or less, depending on the equipment. If stable and modern machines are used in the production, it is usually sufficient to measure the profile in two smaller parts of a floor slab to determine the average spacing, connection geometry, etc.

All measurements should be carried out while the floorboards are conditioned at a normal relative humidity of approx. 45%.

Also in this case, the locking element or the upwardly directed part 8 of the tongue has a guide part 66. The guide part of the locking element comprises parts with a slope which is smaller than the slope of the locking surface and, in this case, also the slope of the tangent TL1. A suitable degree of inclination of the tool which produces the locking surface 45 is indicated by TA2 which in this embodiment is equal to the tangent TL1.

The locking surface 45 of the tongue groove also has a guide part 44 which cooperates with the guide parts 66 of the tongue during inward angling. This control part 44 also includes parts that have a smaller slope than the locking surface.

In the front part of the lower lip 40 there is a rounded guide part 51 which cooperates with the radius in the lower part of the tongue in connection with the lower engaging surface 71 at the point P7 and which enables inward angling.

The lower lip 40 may be flexible. In connection with inward angulation, a small degree of compression can also take place from the contact points between the lower parts of the tongue 38 and the lower lip 40. As a rule, this compression is considerably less than what can be the case for the locking surfaces, since the lower lip 40 can have significantly better elasticity properties than the upper lip 39 and the tongue 38. In connection with inward angulation and upward angulation, the lip can thus be bent downwards. A bending capacity of only 1/10 of a mm or a little more gives, together with material compression and small contact surfaces, good opportunities to form e.g. the lower supporting surfaces 50, 71, so that they can have a slope less than the tangent TL2, while at the same time inward angling can be performed easily. A flexible lip should be combined with a relatively high locking angle. If the locking angle is small, a large tensile load will push the lip downwards, resulting in unwanted coupling cracks and a difference in level between the coupling edges.

Both the tongue groove 36 and the tongue 38 have guide parts 42, 51 and 68, 70 which guide the tongue into the groove and enable it to be clicked in and angled inwards.

Fig. 25 illustrates variants of the invention, where the lower lip 40 is shorter than the upper lip 39, and is therefore positioned at a distance from the vertical plane VP. The advantage is that there will be greater degrees of freedom in the construction of the locking groove 45 with a large tool angle TA, while at the same time a relatively large tool can be used. In order to enable engagement by downward bending of the lower lip 40, the tongue groove 36 is shaped deeper than required by the space for the tip of the tongue 38. The dashed connecting part 4b shows how the parts of the system are related to each other in connection with inward angulation around the upper connecting edges, while the dotted connecting edge part shows how the parts of the system are related to each other in connection with clicking the tongue into the tongue groove by displacing the connecting edge part 4b directly towards the connecting edge part 4a. Fig. 26 shows a further variant for the above-mentioned basic principles. The coupling system is here formed with locking surfaces which are angled at 90° to the surface plane HP and which are significantly more angled than the tangent TL1. Such a preferred locking system can, however, be opened when angled upwards by the fact that the locking surfaces are extremely small and by the fact that the coupling mostly only locks at line contact. If the core is hard, such a locking system can provide high strength. The design of the locking element and locking surfaces allows engagement with only a small amount of downward bending of the lower lip, as indicated by dashed lines. Figures 27a-c show a laying method by inward angling. To simplify the description, one plate is referred to as the track plate and the other as the tongue plate. In practice, the plates are identical. A possible laying method involves the tongue board lying flat on the subfloor, either as a loose board or connected with other boards on one, two or three sides, depending on where in the laying order/row it is placed. The track plate is placed with its upper lip 39 partially over the outer part of the tongue 38, so that the upper coupling edges are in contact with each other. The track plate is then turned downwards towards the subfloor while it is pressed against the connecting edge of the tongue plate until final locking takes place according to fig. 27c.

The sides of the floorboards occasionally have a certain degree of bending. The track plate is pressed and then turned downwards, until parts of the upper lip 39 are in contact with parts of the upwardly directed part or locking element 8 of the tongue and parts of the lower lip 40 are in contact with parts of the lower part of the tongue. In this way, any bending of the sides can be corrected and then the plates can be angled to their final position and locked.

Figures 27a-c show that the inward angulation can take place with a space, or alternatively with only contact between the upper part of the tongue groove and the tongue, or with line contact between the upper and lower parts of the tongue and the tongue groove. In this embodiment, line contact can occur at points P4 and P7. Inward angling can easily take place without significant resistance, and can be finished with a very tight fit that locks the floorboards in their final position with high connection quality, both vertically and horizontally.

In summary, the downward angle can be carried out in practice as follows. The groove plate is moved at an angle towards the tongue plate, where the tongue groove is moved over part of the tongue. The track plate is pressed down the tongue plate and gradually angled downwards using, e.g. compression in the center of the plate and, then on both edges. Since the upper connecting edges over the entire slab are close to each other, or in contact with each other, and the slab has assumed a certain angle with the subfloor, the final downward angling can be carried out.

As the plates have been connected, they can be moved into a locked position in the connection direction, i.e. parallel to the connection edge. Figures 28a-c show how a similar laying can be carried out by angling the tongue plate into the slot plate. Figures 29a-b show connection when clicked in. As the plates are moved horizontally towards each other, the tongue is guided into the groove. During continued compression, the lower lip 40 bends and the locking element 8 snaps into the locking groove or notch 35. It should be emphasized that the preferred coupling system exhibits the basic principles of snapping, where the lower lip is flexible. The coupling system must, of course, be adjusted to the bending capacity of the material and the depth of the tongue groove 36, the height of the locking element 8 and the thickness of the lower lip 40, and should be dimensioned so that snapping is feasible. The basic principles of a coupling system as described herein, which is more practical for use with materials with a lower flexibility and pliability, will appear from the following description and fig. 34.

The described laying methods can be used optionally for all four sides, and can be combined with each other. After laying one side, a lateral displacement usually takes place in the locked position.

In some cases, e.g. in connection with inward angling of the short side as a first action, an upward angulation of two plates usually takes place. Fig. 30 shows a first plate 1, and an upwardly angled second plate 2a and an upwardly angled new third plate 2b which on its short side is already connected with the second plate 2b. After the new plate 2b has been laterally shifted along the short side of the second plate 2a, in the upwardly angled and short side locked position, the two plates 2a and 2b can be angled down, connected, and locked on the long side of the first plate 1. In order that for this method to work, it is required that the new plate 2b can be inserted with its tongue into the tongue groove as the plate is displaced parallel to the second plate 2a and as the second plate 2a has part of its tongue partially brought into the tongue groove, and its upper coupling edge is in contact with the upper coupling edge of the first plate 1. Fig. 30 shows that the coupling system can be made with such a design of the tongue groove, tongue and locking element, so that this is possible.

All laying methods require displacement in the locked position. One exception to lateral displacement in the locked position is the case where several plates are connected on their short sides, after which a whole new row is laid simultaneously. However, this is not a rational laying method.

Figures 31a, 31b show part of a floor plate with a combination coupling. The tongue grooves 36 and 38 can be formed according to one of the designs above. The groove plate has on the underside a known strip 6 with a locking element 8b and a locking surface 10. The tongue side has a locking groove 35 according to a known design. In this embodiment, the locking element 8b with its relatively large control part 9 will function as an additional control element during the first part of the inward angulation, and significantly enables this first part of the inward angulation as positioning takes place and the possible banana shape is straightened out. The locking element 8b causes automatic positioning and compression of the floor plates until the control part of the tongue is engaged with the locking groove 35, and final locking can take place. Laying is considerably simplified, and the connection will be strong through the cooperation of the two locking systems. This connection is very practical for connecting large floor surfaces, especially in public spaces. In the example shown, the strip 6 has been attached to the track side, but it can also be attached to the tongue side. The positioning of the list 6 is thus optional. In addition, the link can both be clicked in and angled upwards and moved laterally in the locked position.

Of course, this coupling can optionally be used in different variants on both the long and short side, and it can optionally be combined with all coupling variants described herein and with other known systems.

A practical combination is a click system on the short side without an aluminum strip. In some cases, it can simplify production. A molding that is attached after manufacture also has the advantage that it can form part of, or the entire lower lip 40. This gives a very large degree of freedom for shaping, with cutting tools, e.g. the upper lip 39 and form locking surfaces with high locking angles. The locking system according to this embodiment can, of course, be made clickable, and it can also be produced with an optional width for the strip, e.g. with a strip 6 which does not project beyond the outer part of the upper lip 39, which is the case in the embodiment according to fig. 50. The strip need not be continuous over the entire length of the link, but may consist of several small parts which are attached with spaces between them, both on the long side and on the short side.

The locking element 8b and its locking groove 35 can be formed with different angles, heights and radii which can be selected optionally, so that they either prevent separation, and/or enable inward angling or snapping.

Figures 32a-d illustrate in 4 steps how inward angling can be carried out. The wide strip 6 makes it possible for the tongue 38 to be placed easily on the strip, and at the beginning of the inward angle. The tongue can then, in connection with downward angling, actually automatically slide into the tongue groove 36. The corresponding laying can be carried out by bringing the strip 6 under the tongue plate. All laying functions described above can also be used in floor slabs with this preferred combination system.

Figures 33 and 34 show a production-specific and optimized connection system for the entire floor slab with a wooden core. Fig. 33 shows how the long side can be formed. In this case, the coupling system is optimized according to primarily inward angulation, upward angulation and a small amount of material waste. Fig. 34 shows how the short side can be formed. In this case, the coupling system is optimized for click-in and high strength. The differences are as follows. The tongue 38 and the locking element of the short side 5a are longer, measured in the horizontal plane. This gives a higher shear strength in the locking element 8. The tongue groove 36 is deeper on the short side 5b, which helps the lower lip to bend downwards to a greater extent. The locking element 8 is on the short side 5a lower in the vertical direction, which reduces the requirement for downward bending of the lower lip in connection with the clicking. The locking surfaces 45, 65 have a higher locking angle and the lower engagement surfaces have a smaller angle. The control parts of the long side 4a, 4b in the locking element and the locking groove are larger for optimal control, while at the same time the contact surface between the locking surfaces is smaller, since the strength requirements are lower than for the short sides. The coupling systems on the long and short sides can consist of different materials or material properties in the upper lip, the lower lip and the tongue, and these properties can be adjusted so that they contribute to the optimization of the different properties that are desired for each the long side and the short side, according to function and strength.

Fig. 35 shows in detail how the connection system of the floor slab can be formed on the long side. The principles described here can of course be applied to both the long side and the short side. Mostly only the parts that have not been described in detail before will now be described.

The locking surfaces 45, 65 have an angle HLA which is greater than the tangent TL1. This gives a higher horizontal locking force. This overbending should be adjusted to the wood material of the core and optimized according to compression and bending stiffness so that inward angulation and upward angulation still take place. The contact surfaces of the locking surfaces should be minimized and adjusted to the properties of the core.

When the planks are connected, a small part, preferably less than half of the extent of the locking element in the vertical direction, constitutes the contact surfaces of the locking element 8 and the locking groove 14. The major part is rounded, inclined or bent guide parts which in the locked position, and during inward and upward angling are not in contact together.

The inventor has discovered that very small contact surfaces in relation to the floor thickness T between the locking surfaces 45, 65 of, e.g. a few tenths of a mm can result in a very high locking force and that this locking force can exceed the shear strength of the locking element in the horizontal plane

(ie the surface plane HP). This can be used to provide locking surfaces with an angle greater than tangent TL1.

In this case, the locking surfaces 45, 65 are flat and parallel. This is advantageous, especially according to the locking surface 55 of the locking groove. If the tool is moved parallel to the locking surface 45, this will not affect the vertical distance to the coupling plane VP, and it is easier to provide a high coupling quality. Of course, small deviations from the plane can produce similar results.

Correspondingly, the lower supporting surfaces 50, 51 are mostly made flat and with an angle VLA2, which in this case is greater than the tangent line TL2 to the point P7 located on the supporting surface 71 closest to the bottom of the tongue groove. This causes inward angulation with clearance throughout most of the angular movement. The supporting surfaces 50, 71 are also relatively small in relation to the floor thickness. These supporting surfaces can also be made largely flat. Flat supporting surfaces enable production according to the principles described above.

The supporting surfaces 50, 71 can also be formed with angles smaller than the slope angle of the tangent TL2. In this case, angulation can partly take place by means of a certain degree of material compression and downward bending of the lower lip 40. If the lower supporting surfaces 50, 71 are small in relation to the floor thickness T, the possibilities of forming the surfaces with angles increase which are respectively greater and less than respectively the tangent TL1 and TL2.

Fig. 36 shows an upward angle of a plate which has a geometry according to fig. 35 and whose locking surfaces therefore have a greater slope than the tangent TL1 and whose supporting surfaces have a smaller slope than the tangent TL2, while these surfaces are at the same time relatively small. The overlap at points P4 and P7 in connection with inward angling and upward angling will then be extremely small. The point P4 can be angled depending on a combination of materials that are compressed at the upper connecting edges Kl, K2 and at the point P4, K3, K4, while at the same time the upper lip 39 and the tongue 38 can bend in the directions B1 and B2 from the contact point B4. The lower lip can bend downwards, away from the contact point P7 in the direction B3.

The upper supporting surfaces 43, 64 are preferably perpendicular to the coupling plane VP. The production is significantly simplified if the upper and lower supporting surfaces are plane-parallel and preferably horizontal.

Once again, reference is made to fig. 35. The circular arc Cl shows e.g. that the upper supporting surfaces can be formed in many different ways within this circular arc Cl without this interfering with the possibilities of angling and clicking. In the same way, the circular arc C2 shows that the inner parts of the tongue groove and the outer parts of the tongue according to the previously described principles can be formed in many different ways without this getting in the way of the possibilities for angling and clicking.

The upper lip 39 is thicker over its total length than the lower lip 40. This is advantageous from the point of view of strength. Moreover, this is advantageous in connection with parquet floors, as a result of which a thicker surface layer of a hard type of wood can be formed.

S1-S5 indicate areas where coupling surfaces on both sides should not be in contact with each other, at least in the coupled position, but preferably also during inward angling. A contact between the tongue and the tongue groove in these areas S1-S5 contributes only marginally to the improvement of locking in the D1 direction and hardly at all to the improvement of locking in the D2 direction. However, a contact prevents inward angulation and lateral displacement, causes unnecessary tolerance problems in connection with manufacture and increases the risk of creaking and unwanted effects as the plate swells.

The tool angle TA, as in fig. 38d is indicated by TA4, forms the locking surface 44 of the notch 35 and acts at the same angle as the angle of the locking surface, and the part of this tool which is positioned in the vertical plane against the tongue groove has a width perpendicular to the tool angle TA which is indicated by TT. The angle TA and the width TT partly determine the possibilities for forming the outer parts 52 of the lower lip 40.

A plurality of relationships and angles are important for an optimal manufacturing method, functionality, costs and strength.

The length of contact surfaces should be minimized. This reduces friction and enables shifting in the locked position, inward angling and snapping in simplifies manufacturing and reduces the risk of swelling problems and creaking. In the preferred example, less than 30% of the surface portions of the tongue 38 constitute contact surfaces with the tongue groove 36. The contact surfaces of the locking surfaces 65, 45 in this embodiment are only 2% of the floor thickness T, and the lower supporting surfaces have a contact surface having only 10% of the floor thickness T. As mentioned above, the locking system in this embodiment has a plurality of parts S1-S5 which form free surfaces without contact with each other. The space between these free surfaces and the rest of the coupling system can be filled with glue, sealant, impregnating agent of various types, lubricant and the like. By free surfaces is meant here the shape of the surfaces in the coupling system which is obtained in connection with machining using the respective cutting tools.

If the coupling has a tight fit, the locking surfaces 65, 45 can prevent horizontal separation, even though they have an angle HLA with the horizontal plane HP that is greater than zero. However, the tensile strength of the coupling system increases significantly as this locking angle becomes greater than as there is a difference in angle between the locking angle HLA of the locking surfaces 45, 65, and the engagement angle VLA2 of the lower supporting surfaces 50, 71, provided that this angle is smaller. If high strength is not required, the locking surfaces can be formed with low angles and little difference in angle with the lower engagement surfaces.

For good connection quality in floating floors, the locking angle HLA and the difference in angle with the lower support surfaces HLA-VLA2 must as a rule be approx. 20°. Even better strength is achieved if the locking angle HLA and the difference in angle HLA-VLA2 e.g. is 30°. In the preferred example according to fig. 35, the locking angle is 50°, and the angle of the supporting surfaces 20°. As shown in previous embodiments, coupling systems can be formed with even higher locking angles and differences in angles.

A large number of tests have been carried out with different locking angles and engagement angles. These tests prove that it is possible to form a high-quality coupling system with locking angles between 40° and 55° and with supporting surface angles between 0° and 25°. It should be emphasized that other conditions can also result in satisfactory functionality.

The horizontal protrusion PA of the tongue should be higher than 1/3 of the thickness T of the floor plate, and it should preferably be approx. 0.5 x T. As a rule, this is necessary for a strong locking element 8 with a guide part to be formed, and for sufficient material to be available in the upper lip 39 between the locking surface 65 and the vertical plane VP.

The horizontal protrusion PA of the tongue 38 should be divided into two substantially equal parts PAI and PA2, where PAI should constitute the locking element and the greater part of PA2 should constitute the supporting surface 65. The horizontal protrusion PAI of the locking element should not be less than 0.2 x the floor thickness. The upper supporting surface 64 should not be too large, especially on the long side of the floor slab. Otherwise, the friction in connection with lateral displacement may be too high. To enable rational manufacture, the depth G of the tongue groove should be 2% deeper than the projection of the tongue PA from the coupling plane VP. The minimum distance from the upper lip to the floor surface perpendicular to the locking groove 35 should be greater than the minimum distance from the lower lip between the lower supporting surface 71 and the back of the floor plate. The tool width TT should be greater than 0.1 x the floor thickness

T.

Figures 37a-c show a floor plate according to the invention. This embodiment shows in particular that the coupling system on

the short side can consist of different materials and material combinations 30b and 30c, and that these can also vary from the connecting material 30 to the long side. E.g. can the tongue groove part 36 of the short sides consist of a harder and more flexible wooden material than e.g. the tongue part 38 which can be hard and rigid and have different properties than the core of the long side. On the short side with the tongue groove 36, it is possible to choose e.g. a type of wood 30b which is more flexible than the wood species 30c on the other short side where the tongue is formed. This is particularly practical in parquet floors with a lamellar core where the upper and lower sides consist of different types of wood and where the core consists of blocks that have been glued together. This construction offers great opportunities to vary the composition of materials to optimize functionality, strength and production costs.

It is also possible to vary the material along the length of one page. Therefore, e.g. the blocks that are positioned between the two short sides be of different types of wood or materials, so that some of them can be selected according to their contribution with suitable properties that improve laying, strength, etc. Different properties can also be achieved with different fiber orientation on the long and short side , plastic materials can also be used on short sides, and e.g. on different parts of the long side. If the floor slab, or parts of its core consists of e.g. plywood with different layers, these layers can be selected so that the upper lip, the tongue and the lower lip both on the long side and the short side can all have parts with different combinations of materials, fiber orientation, etc., which can give different properties according to strength, flexibility , machinability etc.

Fig. 38a-d shows a production method. In the embodiment shown, the connection edge and the tongue groove are produced in 4 steps. The tools used have a tool diameter that is greater than the floor thickness. The tools are used to form an incised groove with a high locking angle in a tongue groove with a lower lip, which projects beyond the incised groove.

To simplify the understanding and comparison with previously described connection systems, the edges of the plates are illustrated with the floor surface directed upwards. Usually, however, the plates are positioned with their surface facing downwards during machining.

The first tool TP1 is a scrubber that acts at an angle TA1 with the horizontal plane. The second tool TP2 can act horizontally and forms the upper and lower supporting surfaces. The third tool TA3 can work mostly vertically but also at an angle, forming the upper connecting edge.

The critical tool is tool TP4 which forms the outer part of the locking groove and its locking surface. TA4 corresponds to TA in fig. 35. As can be seen from fig. 38d, this tool removes only a minimal amount of the material and mostly forms the locking surface at a high angle. In order for the tool not to break, it should be formed with a wide part that is extended beyond the vertical plane. Also, the amount of material to be removed should be as small as possible to reduce wear and tear on the tool. This is achieved with a suitable angle and design of the scrubber TP1.

Thus, this production method is particularly characterized by the fact that at least two cutting tools are required which operate at two different angles to form an incised locking groove 35 in the upper part of the tongue groove 36. The tongue groove can be formed by using even more tools where the tool is used in a different order.

The description is now directed in detail to the method of forming a tongue groove 36 in a floor plate, which has an upper side 2, and a surface plane HP and a connecting edge part 4a with a connecting plane VP directed perpendicular to the upper side. The tongue groove projects from the coupling plane 4a and is delimited by two lips 39, 40, each with a free outer end. In at least one lip, the tongue groove has an incision 35 which comprises a locking surface 45 and is positioned further away from the coupling plane VP than the free outer end 52 of the other lip is. According to the method, machining is carried out using a variety of rotary cutting tools having a larger diameter than the thickness T of the floor plate. According to the method, the cutting tools and the floor plate are made to perform a relative movement relative to each other and parallel to the connecting edge of the floor plate. What characterizes the method is 1) that the incision is formed by means of at least two such cutting tools, which have the axis of rotation angled at different angled at different angles with the top side 2 of the floor plate; 2) that a first of these tools is driven to form portions of the notch farther from the coupling plane VP than the locking surface 45 of the intended notch; and 3) that a second of these tools is driven to form the locking surface 45 of the notch. The first of these tools is operated with its axis of rotation set at a greater angle with the top side 2 of the floor plate than the second of these tools is. The lower lip 40 can be formed to project past the coupling plane VP. The lower lip 40 can also be formed to project to the connecting plane VP. Alternatively, the lower lip 40 can be formed to terminate at a distance from the coupling plane VP.

The first of the tools may, according to one embodiment, be driven with their axis of rotation set at an angle of maximum 85° to the surface plane HP. According to one embodiment, the second of the tools can be operated with its axis of rotation set at an angle of maximum 60° with the surface plane HP. Moreover, it can be ensured that the tools engage the floor plate, in an order depending on the angle of their axis of rotation with the surface plane HP, so that it is ensured that tools with a greater angle of the axis of rotation machine the floor plate before the tools with a smaller angle of the axis of rotation.

Also, a third of the tools may be driven to form the lower portion of the tongue groove 36. This third tool may be brought into contact with the floor plate between the first and second of the tools. The third tool can further be operated with its axis of rotation set at an angle of approx. 90° with the surface plane HP.

Furthermore, the first tool can be operated to machine a wider surface portion of the connecting edge portion 4a of the floor plate than the second of the tools. The second of the tools can be formed so that its surface facing the surface plane HP is profiled to reduce the thickness of the tool, seen parallel to the axis of rotation, within the radial outer parts of the tool. Also, at least three of the tools can be operated with different settings of their axis of rotation to form the notched portions of the tongue groove. The tools can be used to machine a floor plate made of wood, or wood fiber-based materials.

Fig. 39 shows how a coupling system can be formed to enable compensation for swelling. Since the relative humidity increases with the change between cold and warm weather, the surface layer 32 swells, and the floorboards 4a and 4b are pushed apart. If the coupling has no flexibility, coupling edges 41 and 61 may be crushed, or the locking element 8 may break. This problem can be solved by designing the coupling system to achieve the following properties individually, and in combination contribute to reducing the problem.

The connection system can be formed so that the floor plates can have a small gap as the connection edges are pressed together horizontally, e.g. in connection with production and at normal relative humidity. A gap of a few hundredths of a mm helps to reduce the problem. A negative gap, i.e. bias, can give it the opposite effect.

If the contact surface between the locking surfaces 45, 65 is small, the coupling system can be formed so that the locking surfaces are more easily compressed than the upper coupling edges 41, 61. The locking element 8 can be formed with a groove 64a between the locking surface and the upper horizontal supporting surface 64. With a suitable design of the tongue 38 and the locking element 8, the outer part 69 of the tongue can be bent outwards towards the inner part 48 of the tongue groove and act as an elastic element in connection with swelling and shrinking of the surface layers.

In this embodiment, the upper supporting surfaces of the coupling system are formed parallel to the horizontal plane for maximum vertical locking. It is also possible to achieve expansion capability by using a compressible material between e.g. the two locking surfaces 45, 65, or by choosing compressible materials for the tongue or groove part. Fig. 40 shows a coupling system which has been optimized for high stiffness in the tongue 38. In this case, the outer part of the tongue is in contact with the inner part of the tongue groove. If this contact surface is small and if the contact occurs without particularly high compression, the coupling system can be moved in the locked position. Fig. 41 shows a coupling system where the lower supporting surfaces 50, 71 have two angles. The parts of the supporting surfaces on the outside of the coupling plane are parallel to the horizontal plane. Into the coupling plane, closest to the inner part of the tongue groove, they have an angle corresponding to the tangent of the circular arc 32 which is tangent to the innermost edge of the parts of the supporting surfaces which are connected to each other. The locking surfaces have a relatively small locking angle. The strength can still be sufficient since the lower lip 40 can be made hard and rigid, and since the difference in angle is large with the parallel part of the lower supporting surfaces 50, 71. In this embodiment, the locking surfaces 45, 65 also serve as upper supporting surfaces. The coupling system does not have any upper supporting surfaces in addition to the locking surfaces which therefore also prevent vertical separation. Figures 42a and 42b show a coupling system which is practical for locking the short side, which can have high tensile strength also in softer materials since locking elements 8 have a large horizontal shear-absorbing surface. The tongue 38 has a lower part which is positioned on the outside of the circular arc C2, and which therefore does not follow the above-described basic principles of inward angling. As can be seen from fig. 42b, the coupling system can still be released by upward angling around the upper coupling edges, since the locking element 8 of the tongue 38, after the first upward angling operation, can leave the tongue groove by being pulled out horizontally. The previously described principles for inward angling and upward angling around upper coupling edges must therefore be satisfied to enable upward angling until the coupling system can be released in another way, by e.g. to be pulled out, or in combination with unclicking as the lower lip 40 is bent. Figures 43a-c show the basic principles for how the lower part of the tongue should be formed in relation to the lower lip 40 to enable horizontal snapping in according to the invention in a coupling system with the locking groove in a rigid upper lip 39 and with a flexible lower lip 40. In this execution, the upper lip 39 is significantly stiffer, i.a. due to the fact that it may be thicker, or that it may consist of harder and stiffer materials. The lower lip 40 can be thinner and softer, and in connection with clicking in, the majority of the bending will therefore take place in the lower lip 40. Clicking in can i.a. is enabled significantly by the maximum bending of the lower lip 40 being limited as much as possible. Fig. 43a shows that the bending

of the lower lip 40 will increase to a maximum bending level Bl which is characterized by the tongue 38 being brought into the tongue groove 36 so far that the rounded guide parts will come into contact with each other. As the tongue 38 is brought in even more, the lower lip 40 will bend back until snapping is complete and the locking element 8 is fully brought into its final position in the locking groove 35. The lower and outermost part 49 of the tongue 38 should be designed so that it does not bend down the lower lip 40, which lower lip 40 should instead be pressed down at the lower supporting surface 50. This part 49 of the tongue should have a shape that either comes into contact with, or clears from, the maximum bending level of the lower lip 40 as this lower lip 40 is bent around the outer part of the lower engaging surface 50 of the tongue 38. If the tongue 38 has a shape which in this position overlaps the lower lip 40, indicated by the dashed line 49b, the bending B2 according to fig. 43b be significantly larger. This can cause great friction in connection with engagement and a risk of the coupling being destroyed. Fig. 43c shows that the maximum bending can be limited by the tongue groove 36 and the tongue 38 being constructed in such a way that there is a space S4 between the lower and outer part 49 of the tongue and the lower lip 40.

Horizontal snap-in is usually used in connection with snap-in of the short side after locking the long side. As the long side is clicked in, it is also possible to click the coupling system according to the invention with one plate in a slightly upwardly angled position. This upwardly angled click position is depicted in fig. 44. Only a narrow bend B3 of the lower lip 40 is needed for the control part 66 of the locking element to come into contact with the control part 44 of the locking groove, so that the locking element can then be brought in by downward angling into the locking groove 35.

Figures 45-50 show different variants of the invention which can be used on the long or short side and which can be produced using large rotating cutting tools.

With modern manufacturing technology, according to the invention, it is possible to form complicated shapes by machining sheet materials, with low costs. It should be emphasized that most of the depicted geometries in these and previously mentioned figures can of course be formed e.g. by extrusion, but this method is usually considerably more expensive than machining and is not practical for forming most sheet materials commonly used in flooring. Figures 45a and 45b show a locking system according to the invention where the outer part of the tongue 38 has been shaped to be flexible. This flexibility is achieved by splitting the tip of the tongue, during clicking the lower lip 40 bends downwards, and the outer lower part of the tongue 38 bends upwards. Fig. 46a and 46b show a locking system with a split tongue. During clicking, the two parts of the tongue bend towards each other, while the two lips simultaneously bend away from each other.

These two connection systems are such as to enable respectively inward and outward angling, and locking and disconnection. Figures 47a and 47b show a combination coupling where a separate part 40b forms a protruding part of the lower lip and where this part can be flexible. The coupling system is angled. The lower lip which forms part of the core is formed with its supporting surface in such a way that snapping in can take place without this lip having to be bent. Only the projecting separate part which can be made of aluminum sheet is flexible. The coupling system can also be formed so that both parts of the lip are flexible. Figures 48a and 48b show the snap-in of a combination coupling with a lower lip consisting of two parts, where only the separate lip constitutes the supporting surface. This connection system can e.g. is used on the short side together with another connection system according to the present description. The advantage of this connection system is that e.g. the locking groove 35 can rationally be formed with a large degree of freedom, and by using large cutting tools. After the machining, the outer lip 40b is attached, and its shape does not affect the possibilities of machining. The outer lip 40b is flexible and in this embodiment has no locking element. Another advantage is that the coupling system enables coupling of extremely thin core materials since the lower lip can be made very thin. The core material can e.g. be a thin compact laminate, and the upper and lower layers can be relatively thick layers, e.g. of cork or soft plastic materials, which can provide a soft and sound-absorbing floor. Using this technology, it is possible to connect core materials with a thickness of approx. 2 mm compared to common core materials which are usually no thinner than 7 mm. The savings in thickness that can be achieved can be used to increase the thickness of the other layers. It is obvious that this connection can also be used in thicker materials. Figures 4 9 and 50 show two variants of combination couplings which can be used e.g. in the short side in combination with other preferred systems. The combination coupling according to fig. 49 can be made in an embodiment where the strip forms a protruding flexible part of the tongue and the system will then have a function corresponding to that in fig. 45. Fig. 50 shows that this combination coupling can be formed with a locking element 8b in the outer lower lip 40b which is positioned in the coupling plane. Figures 51a-f show a laying method that can be used to connect floorboards by a combination of horizontal joining, upward angling, clicking into the upwardly angled position and downward angling. This laying method can be used for floorboards according to the invention, but it can also be used on optional mechanical connection systems in floors with such properties that the laying method can be used. To simplify the description, the laying method is shown in which one plate, referred to as the track plate, is connected with the other plate, referred to as the tongue plate. The plates are in practice

identical. It is obvious that the entire laying sequence can also be carried out when the tongue side is connected to the groove side in the same way.

A tongue plate 4a with a tongue 38 and a groove plate 4b with a tongue groove 36 lies in the initial position flat on a subfloor according to fig. 51a. The tongue 38 and the tongue groove 36 have locking means which are separated vertically and horizontally. After that, the groove plate 4b is displaced in the direction F1 towards the tongue plate 4a until the tongue 38 is in contact with the tongue groove 36 and until the upper and lower parts of the tongue are partially brought into the tongue groove according to fig. 51b. This first operation forces the connecting edge part of the plates to take the same relative vertical positions over the entire length of the plate, and any possible difference in the arch shape will thus be corrected.

If the track plate is moved towards the tongue plate, the connecting edge part of the track plate will be lifted easily in this position. The track plate 4b is then angled upwards with an angular movement S1 while at the same time being kept in contact with the tongue plate or alternatively pressed in the direction Fl against the tongue plate 4a according to fig.

51c. Since the track plate 4b achieves an angle SA with the subfloor which corresponds to an upwardly angled click position, according to the description above and as shown in fig. 44, the slot plate 4b can be moved towards the tongue plate 4a so that the upper coupling edges 41, 61 come into contact with each other, and so that the locking means for the tongue are partially brought into the locking means of the tongue slot by a click function.

This click function in the upwardly angled position is characterized by the outer parts of the tongue groove expanding and springing back. The expansion is significantly less than what is needed in connection with clicking in the horizontal position. The click angle SA depends on the force with which the plates are pressed together in connection with the upward angle of the track plate 4b. If the pressing force in the direction Fl is high, the plates will click into place at a lower angle SA than when the force is low. The click-in position is also characterized by the fact that the control parts of the locking means are in contact with each other so that they can perform their click-in function. If the plates are banana-shaped, they will be straightened and locked in connection with the click. The track plate 4b can then be angled downwards with an angular movement S2 combined with pressure against the coupling edge according to fig. 51e and is locked against the tongue plate in its final position. This is depicted in fig. 51 f.

Depending on the construction of the coupling, it is possible, with great accuracy, to determine the click angle SA which provides the best functionality according to the requirement that the click should take place with a significant amount of force and that the control parts of the locking means should be in such an engagement that they can holding together a possible banana shape, so that a final locking can take place without the risk of the coupling system being destroyed.

According to the preferred laying method, the floorboards can be installed without any real aids. In some cases, the installation can be made possible if it is carried out with suitable means according to figures 52a and 52b. A preferred aid according to the present description can be a hammer or press block 80 which is constructed to have a front and lower part 81 which angles the track plate over, as it is brought under the edge part of the floor plate. It has an upper stopper edge 82 which in the upwardly angled position is in contact with the edge part of the track plate. As the hammer block 80 is brought under the track plate so that the stop block edge 82 is in contact with the floor plate, the floor plate will have the predetermined click angle. The tongue groove of the groove plate 4a can now be clicked together with the tongue of the tongue plate by pressing or hammering against the hammer block. Of course, the hammer block can be moved to different parts of the plate. It is obvious that this can take place in combination with another pressing against other parts of the plate, by using several hammer blocks and by using different types of aids that give a similar result, e.g. one aid angles the plate up to the click-in angle and another is used for compression. The same method can be used if someone instead wants to angle up the groove side of the new plate and connect it with the tongue side of the previously laid plate.

The description will now be directed to various aspects of a tool for laying floor tiles. Such a tool for laying floorboards by connecting a tongue and groove joint thereof can be constructed as a block 80 with an engaging surface 82 to engage a connecting edge 4a, 4b of the connecting edge part of the floorboard. The tool can be formed as a wedge for insertion under the floorboard and has the engagement surface 82 arranged near the thick end of the wedge. The engagement surface 82 of the tool may be concavely bent for at least partial inclusion of the connecting edge 4a, 4b of the floor plate. Also, the wedge angle Sl of the wedge and the position of the engagement surface 82 on the thick part of the wedge can be adjusted to achieve a predetermined lifting angle of a floorboard as it is lifted by the wedge 80 and the connecting edge of the floorboard comes into contact with the engagement surface 82. 82 of the wedge 80 can be formed to stop against a coupling edge part 4b having a tongue 38 directed obliquely upwards to connect an incised tongue groove 36 formed at the opposite coupling edge part 4a of the floorboard with the tongue 38 of a previously laid floorboard. Alternatively, the stopper surface 82 of the wedge may be formed to stop against a coupling edge portion 4a, which has an incised groove 36, to engage a tongue 38 directed obliquely upward, and formed on the opposite coupling edge portion 4b of the floor plate.

The tool described above can be used for mechanically connecting floor plates by lifting one floor plate relative to another, and for connecting and locking mechanical locking systems of the floor plates. The tool can also be used for mechanically connecting such a floor plate with another such floor plate by clicking together the mechanical locking systems of the floor plates while the floor plate is in its raised position.

Furthermore, the tool can be used so that the engagement surface 82 of the wedge is stopped against a coupling edge part 4b

which has a tongue 38 directed obliquely upwards to engage an incised groove 36 formed on the opposite connecting edge part 4a of the floor plate with the tongue 38 of a previously laid floor plate. Alternatively, the tool can be used so that the engaging surface 82 of the wedge is stopped against a coupling edge part 4a which has an incised groove 36, for coupling a tongue 38 which is directed obliquely upwards and formed on the opposite coupling part 4b of the floor plate with the incised groove 38 of a previous laid floor slab.

Fig. 53 shows that the plates 2a and 2b, after being connected with adjacent plates along the long side edges, can be moved into a locked position in the direction F2 so that the connection of the other two sides can find its place by a horizontal click.

Clicking in the upwardly angled position can take place on the long sides as well as on the short sides. If the short side of one plate has first been connected, its long side can also be clicked into the upwardly angled position by angling this plate with its locked short side up so that it assumes its click angle. After that, click-in occurs in the upwardly angled position, while at the same time displacement occurs in the locked position along the short side. After clicking in, the plate is angled down and locked on both the long side and the short side.

Furthermore, figures 53 and 54 describe a problem that can arise in connection with the snapping of two short sides of two plates 2a and 2b which have already been connected on their long sides with another first plate 1. As the floor plate 2a is to be snapped into the floor plate 2b, they are inner corner parts 91 and 92 closest to the long side of the first plate 1, in the same plane. This is the result of the fact that the two plates 2a and 2b are connected to the same floor plate 1b on their respective long sides. According to fig. 54b showing the part C3-C4, the tongue 38 cannot be brought into the tongue groove 36 to start the downward bending of the lower lip 40. In the outer corner parts 93, 94 on the other long side in the part C1-C2 shown in fig. 54a, the tongue 38 can be brought into the groove 36 to start the downward bending of the lower lip 40 by the plate 2b being automatically angled up corresponding to the height of the locking element 8.

Thus, the inventor has discovered that there can be problems in connection with the snap-in of inner corner parts in lateral displacement in the same plane and that these problems can cause a high snap-in resistance and a risk of breakage in the coupling system. The problem can be solved by a suitable coupling design and material selection that enables material-deformation bending in several parts of the coupling.

When such a specially designed coupling system is clicked in, the following occurs. In lateral displacement, the outer guide parts 42, 68 of the tongue and the upper lip cooperate, forcing the locking element 8 of the tongue under the outer part of the upper lip 39. The tongue bends downwards and the upper lip bends upwards. This is indicated by arrows in fig. 54b. The corner part 92 in fig. 53 is pressed upwards by bending the lower lip 40 on the long side of the plate 2b and by the corner part 91 being pressed downwards by bending the upper lip on the long side of the plate 2a upwards. The coupling system should be constructed so that the sum of these 4 deformations is so great that the locking element can slide along the upper lip and click into the lock's 36 expander in connection with clicking. However, it is not known that it can be an advantage if the tongue, which should normally be rigid, is also designed to be able to bend in connection with snapping. Such an embodiment is shown in fig. 55. A groove or similar 63 can be made at the upper and inner part of the tongue in the vertical plane VP. The entire protrusion PB of the tongue from its inner to its outer part can be extended, and it can e.g. is made larger than half the floor thickness T.

Figures 56 and 57 show how the parts of the coupling system bend in connection with snapping at the inner corner part 91, 92 (Fig. 57) and the outer corner part 93, 94

(Fig. 56) of two floor plates 2a and 2b. To simplify production, it is necessary that only the thin lip and tongue bend. In practice, of course, all parts exposed to pressure will be compressed and bent to varying degrees, depending on thickness, flexibility, composition of materials, etc.

Fig. 56a and 57a show the position as the edges of the plates come into contact with each other. The coupling system is constructed in such a way that even in this position the outermost tip of the tongue 38 will be inside the outer part of the second lip 40. As the plates are pushed even more towards each other, the tongue 38 in the innermost corner 91, 92 will press the plate 2b upwards according to figures 56b, 57b. The tongue will bend downwards and the plate 2b at the outermost corner 93, 94 will be angled upwards. Fig. 57c shows that the tongue 38 at the innermost corner 91, 92 will be bent downwards. At the outer corner 93, 94 according to fig. 56c, the tongue 38 is bent upwards, and the lower lip 40 is bent downwards. According to figures 56b, 57d, this bending continues as the plates are moved further towards each other, and now the lower lip 40 is also bent at the inner corner 91, 92, according to fig. 57d. Figures 56c, 57e show the click-in position. Clicking in can thus be made possible significantly if the tongue 38 is flexible and if the outer part of the tongue 38 is positioned into the outer part of the lower lip 40 as the tongue and the groove come into contact with each other as the plates are in the same plane in connection with clicking in which takes place after the floor slab is already locked along its other two sides.

Several variants may exist within the scope of the invention. The inventor has produced and evaluated a large number of variants where different parts of the coupling system are produced with different widths, lengths, thicknesses, angles and radii from a number of different plate materials and from homogeneous plastic and wooden panels. All coupling systems have been tested in an upside-down position and with clicking and angling of track and tongue plates relative to each other, and with different combinations of systems described here and also known systems on the long side and short side. Locking systems have been produced where locking surfaces also have upper engagement surfaces, where the tongue and groove have had a variety of locking elements and locking grooves, and where also the lower lip and the lower part of the tongue have been shaped with horizontal locking means in the form of locking elements and locking grooves.

Claims (63)

1. Floor system comprising several floor plates (1,1') which are mechanically connectable by a connection plane (VP), each of the floor plates (1,1') has a core (30), a front side (2, 32), a back side ( 34) and opposite coupling edge parts (4a, 4b), one of which (4a) is shaped like a tongue groove (36) which is delimited by upper and lower lips (39, 40) and by a bottom (48), and the other (4b) is shaped like a tongue (38) which has an upwardly directed part (8) at its free outer end, where: - the tongue groove (36), seen from the coupling plane (VP), has the form of an incised groove (36) with an opening, an inner part (35) and an inner locking surface (45), and - at least parts of the lower lip (40) are shaped integrally with the core (30) of the floor plate , and - the tongue (38) has a locking surface (65) which is shaped to cooperate with the inner locking surface (45) in the tongue groove (36) of an adjacent floor plate, two such floor plates (1, 1') being mechanically connected, as that their front sides (4a, 4b) are positioned in the same surface plane (HP) and meet at the coupling plane (VP) directed perpendicular thereto, characterized in that: - at least the main part of the bottom end (48) of the tongue groove, seen parallel to the surface plane (HP), is positioned further away from the coupling plane (VP) than the outer end (69) of the tongue (38), - the inner locking surface (45 ) of the tongue groove (36) is formed on the upper lip (39) within the incised part (35) of the tongue groove to cooperate with the corresponding locking surface (65) of the tongue (38), which locking surface is formed on the upwardly directed part (8) of the tongue (38) to prevent two mechanically connected plates being pulled apart in a direction D2 perpendicular to the connection plane (VP), - the lower lip (40) has a supporting surface (50) - to cooperate with a corresponding supporting surface (71) on the tongue (38) at a distance from the bottom end (48) of the incised groove, the purpose of the supporting surface being to cooperate to counteract a relative displacement of two mechanically coupled plates in a direction (Dl) perpendicular to the surface plane (HP), - that all parts of the parts of the lower lee ppe (40) which is connected to the core, seen from point (C) where the surface plane (HP) and the connection plane (VP) intersect, lies outside a plane (LP2) which is further away from said point, than a locking plane (LPl) which is parallel thereto and which is tangent to the cooperating locking surfaces (45, 65) of the tongue groove (36) and the tongue (38) where the locking surfaces are most angled relative to the surface plane (HP), and - the upper (39) and lower (40) lips and tongue (38) of the coupling edge members (4a, 4b) are designed to enable disconnection of two mechanically coupled floor plates by upward rotation of one floor plate relative to the other about a center of rotation (C) near a point of intersection between the surface plane (HP) and the coupling plane (VP) for disconnecting the tongue (38) of one floor plate (1') and the tongue groove (36) of the other floor plate (1). 2. Floor system in accordance with claim 1, characterized in that the upper (39) and lower lips (40) and the tongue (38) of the connecting edge parts (4a, 4b) are designed to enable the connection of two of said floor plates (1, 1' ) in that one of said floor plates, while the two floor plates are largely in contact with each other, is pivoted downward relative to the other, about a center of rotation (C) near a point of intersection between the surface plane (HP) and the coupling plane (VP) to connect the tongue of one floorboard with the tongue groove of the other floorboard. 3. Floor system in accordance with claim 1 or 2, characterized in that the incised groove (36) and the tongue (38) have such a design that one of said floor plates (1', 1) which is mechanically connected with a corresponding plate is displaceable in a direction (D3) along the coupling plane (VP) . 4. Floor system in accordance with claim 1, 2 or 3, characterized in that the tongue (38) and the incised groove (36) are designed to enable connection and disconnection of one of said floor plates, with and from another of said floor plates by pivoting one plate relative to the other, while maintaining contact between the floor plates at a point (C) on the joint edge portions of the floor plates near the intersection of the surface plane (HP) and the joint plane (VP). 5. Floor system in accordance with one or more of the preceding claims, characterized in that the tongue (38) and the incised groove (36) are designed to enable connection and disconnection of the floor plates by pivoting one of said floor plates relative to another, while contact is maintained between the floor plates at a point on the mating edge portions of the plates near the intersection of the surface plane (HP) and the mating plane (VP) without significant contact between the side of the tongue (38) directed away from the surface plane (HP) and the lower lip. 6. Floor system in accordance with one or more of claims 1-4, characterized in that the tongue (38) and the incised groove (36) are designed to enable connection and disconnection of the floor plates (1, 1') by pivoting one of the aforementioned floor plates relative to one another, while maintaining contact between the floor plates at a point on the connecting edge portions of the floor plates near the intersection of the surface plane (HP) and the connection plane (VP) and substantially in-line contact between the sides of the tongue (38) directed toward the surface plane (HP) and away from the surface plane (HP) and respectively the upper (39) and lower (40) lip. 7. Floor system in accordance with one or more of the preceding claims, characterized in that the distance between the locking plane (LP2) and the plane (LB1) is parallel to it, beyond which all parts of the parts of the lower lip (40) which are connected to the core ( 30) is at least 10% of the thickness (T) of the floor slab. 8. Floor system in accordance with one or more of the preceding claims, characterized in that the lock-over tracks (45, 65) of the upper lip (39) and the tongue (38) form an angle with the surface plane (HP) of less than 90° , but at least 20°. 9. Floor system in accordance with claim 8, characterized in that the locking surfaces (45, 65) of the lower lip (39) and the tongue (38) form an angle to the surface plane (HP) of at least 30°. 10. Floor system in accordance with one or more of the preceding claims, characterized in that the incised groove (36) and the tongue (38) are constructed so that the outer end (69) of the tongue (38) lies at a distance from the incised groove (36) along substantially the total distance from the interlocking locking surfaces (45, 65) of the upper lip (39) and tongue (38) to the cooperating supporting surfaces (50, 71) of the lower lip (40) and the tongue (38). 11. Floor system in accordance with claim 10, characterized in that any surface part with contact between the outer end (69) of the tongue (38) and the incised groove (36) protrudes less in the vertical plane than the locking surfaces (45, 65) do as two such plates (1, 1') are mechanically connected. 12. Floor system in accordance with one or more of the preceding claims, characterized in that the edge parts (4a, 4b) with their tongue (38) and tongue groove (36) are constructed so that when two of said floor plates are connected, there is surface contact between the edge parts (4a , 4b) along at least 30% of the edge surface of the edge part (4b) which supports the tongue, measured from the upper side of the respective floor plate to its lower side. 13. Floor system in accordance with one or more of the preceding claims, characterized in that cooperating supporting surfaces (50, 71) of the tongue (38) and of the lower lip (40) are parallel to the surface plane (HP) or directed at an angle thereto which is equal to or less than a tangent to a circular arc which is tangent to the supporting surfaces which engage each other at a point near the bottom (48) of the incised groove, and which has its center at a point (C) where the surface plane (HP) and the coupling plane (VP) intersect, seen in cross-section through the floor slab. 14. Floor system in accordance with claim 13, characterized in that the interacting supporting surfaces (50, 71) of the tongue (30) and the lower lip (40) are set at an angle of 0-30° with the surface plane (HP). 15. Floor system in accordance with claim 14, characterized in that the interacting supporting surfaces (50, 71) of the tongue (38) and the lower lip (40) are set at an angle of at least 10° with the surface plane (HP). 16. Floor system in accordance with claim 14 or 15, characterized in that the cooperating supporting surfaces (50, 71) of the tongue (38) and the lower lip (40) are set at an angle of a maximum of 20° with the surface plane (HP). 17. Floor system according to claim 13, characterized in that the cooperating supporting surfaces (50, 71) of the tongue (38) and the lower lip (40) are set at substantially the same angle with the surface plane (HP) as a tangent to a circular arc which is tangent to the supporting surfaces (50, 71) and which has its center at the point where the surface plane (HP) and the connection plane (VP) cross, seen in cross-section through the respective floor plate. 18. Floor system in accordance with claim 13, characterized in that the cooperating supporting surfaces (50, 71) of the tongue (38) and the lower lip (40) are set at a greater angle with the surface plane (HP) than a tangent to a circular arc which is tangent to the supporting surfaces which engage each other at a point nearest the bottom of the slotted groove, and which is centered at a point where the surface plane (HP) and the coupling plane (VP) intersect. 19. A floor system in accordance with any of the preceding claims, characterized in that the supporting surfaces (50, 71) of the tongue (38) and the lower lip (40), which are designed for cooperation, are set at a smaller angle with the surface plane ( HP) than the cooperating locking surfaces of the upper lip (39) and the tongue (38) are. 20. Floor system in accordance with claim 19, characterized in that the supporting surfaces of the tongue (38) and the lower lip (40), which are designed for cooperation, are angled in the same direction, but at a smaller angle with the surface plane (HP) , than the cooperating locking surfaces (50, 71) of the upper lip (39) and the tongue (38). 21. Floor system in accordance with one or more of claims 13-20, characterized in that the supporting surfaces (50, 71) form an angle at least 20° greater with the surface plane (HP) than the locking surfaces (45, 65). 22. Floor system in accordance with one or more of the preceding claims, characterized in that part of the locking surface (45) of the upper lip (39) is closer to the bottom (48) of the tongue groove than part of the supporting surfaces (50 , 71) do. 23. Floor system in accordance with one or more of the preceding claims, characterized in that the locking surfaces (45, 65) of the upper lip (39) and the tongue (38) are mainly flat, at least within the surface parts that must interact with each other as two of the mentioned floor plates are connected. 24. Floor system in accordance with claim 23, characterized in that the tongue (38) has a control surface which lies outside the locking surface of the tongue (38), seen from the connection plane (VP), and which has a smaller angle with the surface plane than this locking surface has. 25. Floor system in accordance with one or more of the preceding claims, characterized in that the upper lip (39) has a control surface (42) which is closer to the opening of the tongue groove (36) than the locking surface (45) of the upper lip does, and which has a smaller angle with the surface plane (HP) than the locking surface (45) of the upper lip. 26. Floor system in accordance with one or more of the preceding claims, characterized in that the lower lip (40) projects to, or preferably ends at a distance before the connection plane (VP). 27. Floor system in accordance with one or more of the preceding claims, characterized in that the lower lip (40) is shorter than the upper lip (39) and ends at a distance from the connection plane (VP), and that at least parts of the supporting surfaces (50,71) of the lower lip (40) and tongue (38) lie at a greater distance from the coupling plane (VP) than the inclined locking surfaces (45, 65) of the upper lip (39) and tongue (38) do . 28. Floor system in accordance with one or more of the preceding claims, characterized in that the locking surface (65) of the tongue (38) lies at a distance of at least 0.1 times the thickness (T) of the respective floor plate (1, 1') from the tip (69) of the tongue (38). 29. Floor system in accordance with one or more of the preceding claims, characterized in that the vertical protrusion of the cooperating locking surfaces (45, 65) is less than half of the vertical protrusion of the notch (35) seen from the connection plane (VP) and parallel with the surface plane (HP). 30. Floor system in accordance with one or more of the preceding claims, characterized in that the locking surfaces (45, 65), seen in a vertical section through the respective floor plate, have a protrusion that is at least 10% of the thickness (T) of the respective floor plate. 31. Floor system in accordance with one or more of the preceding claims, characterized in that the length of the tongue (38), viewed perpendicularly away from the connection plane (VP), is at least 0.3 times the thickness (T) of the floor plate. 32. Floor system in accordance with one or more of the preceding claims, characterized in that the connecting edge part (4b) which supports the tongue and/or the connecting edge part (4a) which supports the tongue groove has a hollow (63) which lies above the tongue and ends at a distance from the surface plane (HP). 33. Floor system in accordance with one or more of the preceding claims, characterized in that the upper lip (39) and the tongue (38) have contact surfaces (43, 64) which in the locked state interact with each other and which lie within an area between the connection plane (VP) and the locking surfaces (45, 65) of the tongue (38) and the upper lip (39), which in their locked state interact with each other. 34. Floor system in accordance with claim 33, characterized in that the contact surfaces (43, 64) are mainly flat. 35. Floor system in accordance with claim 33 or 34, characterized in that the contact surfaces (43, 64) are sloped upwards to the surface plane (HP) in the direction towards the connection plane (VP). 36. Floor system in accordance with claim 33 or 34, characterized in that the contact surfaces (43, 64) are mainly parallel to the surface plane (HP). 37. Floor system in accordance with one or more of the preceding claims, characterized in that the lower lip (40) of the tongue groove (36) is flexible. 38. Floor system in accordance with one or more of the preceding claims, characterized in that it is shaped like a click lock that can be opened by angling one plate (1') relative to the other (1) upwards. 39. Floor system in accordance with one or more of the preceding claims, characterized in that it is designed to connect one of said previously laid floor slabs with a new floor slab by a compressive movement, mainly parallel to the surface plane (HP) of the previously laid slab for snapping together the parts of the locking system. 40. Floor system in accordance with one or more of the preceding claims, characterized in that the incised groove (36), seen in cross-section, has an outer opening part which slopes inwards in a funnel shape. 41. Floor system in accordance with claim 40, characterized in that the upper lip (39) has an inclined edge (42) on its outer edge farthest from the surface plane (HP). 42. Floor system in accordance with one or more of the preceding claims, characterized in that the tongue, seen in cross-section, has a tip (69) which slopes. 43. Floor system in accordance with one or more of the preceding claims, characterized in that the tongue (38) seen in cross-section has a two-part tip with an upper (38a) and a lower (38b) tongue part. 44. Floor system in accordance with claim 43, characterized in that the upper (38a) and lower (38b) tongue parts of the tongue (38) are formed from different materials with different material properties. 45. Floor system in accordance with one or more of the preceding claims, characterized in that the tongue groove and the tongue (38) are formed integrally with the respective floor plate (1, 1')• 46. Floor system in accordance with one or more of the preceding claims, characterized in that the locking surfaces (45, 65) are set at a greater angle with the surface plane (HP) than a tangent to a circular arc which is tangent to the locking surfaces (45, 65) which interlock at a point near the bottom (48) of the slotted groove, and which are centered at the point where the surface plane (HP) and the coupling plane (VP) intersect. 47. Floor system in accordance with one or more of the preceding claims, characterized in that the upper lip (39) is thicker than the lower lip (40). 48. Floor system in accordance with one or more of the preceding claims, characterized in that the minimum thickness of the upper lip (39) adjacent to the notch (35) is greater than the maximum thickness of the lower lip (40) adjacent to the supporting surface (50). 49. Floor system in accordance with one or more of the preceding claims, characterized in that the extent of the supporting surfaces (50, 71) is a maximum of 15% of the thickness (T) of the respective floor plate. 50. Floor system in accordance with one or more of the preceding claims, characterized in that the vertical extent of the tongue groove (36) between the upper (39) and the lower (40) lip, measured parallel to the connection plane (VP) and at the outer end of the supporting surface (43), is at least 30% of the thickness (T) of the respective floor plate. 51. Floor system in accordance with one or more of the preceding claims, characterized in that the depth of the tongue groove (36), measured from the connection plane (VP), is at least 2% greater than the corresponding length of the tongue (38). 52. Floor system in accordance with one or more of the preceding claims, characterized in that the tongue (38) has different material properties than the upper (39) and the lower (40) lip. 53. Floor system in accordance with one or more of the preceding claims, characterized in that the upper lip (39) is stiffer than the lower lip (40). 54. Floor system in accordance with one or more of the preceding claims, characterized by the upper (39) and lower (40) lips being made of materials with different properties. 55. Floor system in accordance with one or more of the preceding claims, characterized in that the locking system further comprises a second mechanical lock which is formed by: - a locking groove (14) which is formed on the underside of the connecting edge part (4b) which supports the tongue (38), and which projects parallel to the coupling plane (VP), and - a locking strip which is attached integrally to the coupling edge part (4a) from the respective floor plate under the tongue groove (36) and projects along essentially the entire length of the coupling edge part and which has a locking component (6) which projects from the list and which comes when two such floor plates are mechanically connected, is received in the locking groove (14) of the adjacent floor plate (1'). 56. Floor system in accordance with claim 55, characterized in that the locking strip (6) projects past the connection plane. 57. Floor system in accordance with any one of the preceding claims, characterized in that it is formed in a plate with a core of wood fiber-based material. 58. Floor system in accordance with claim 52, characterized in that it is formed in a floor plate with a wooden core. 59. Floor system in accordance with one or more of the preceding requirements, characterized in that the floor plate is four-sided and has sides that are parallel in pairs. 60. Floor system in accordance with claim 59, characterized in that the floor plates have mechanical locking systems in all its four side edge parts. 61. Floor system in accordance with claim 60, characterized in that the floor plates have mechanical click locking systems on two opposite side edge parts. 62. Floor system in accordance with claim 61, characterized in that the floor plates, on two opposite short sides of the floor plates, have the incised groove (36) and the tongue (38) shaped for interlocking with a click function. 63. Floor slab to produce the floor system in accordance with one or more of the preceding claims, where the floor slabs are mechanically connectable with an identical floor slab at a connection plane (VP), each of the floor slabs (1,1') has a core (30), a front side (2, 32), a back side (34) and opposite connecting edge parts (4a, 4b), one of which (4a) is shaped like a tongue groove (36) which is delimited by upper and lower lips (39, 40) and by a bottom (48), and the other (4b) is shaped like a tongue (38) which has an upwardly directed part (8) at its free outer end, where: - the tongue groove (36), seen from the coupling plane (VP), has the form of an incised groove (36) with an opening, an inner part (35) and an inner locking surface (45), and - at least parts of the lower lip (40) are shaped integrally with the core (30) of the floor plate , and - the tongue (38) has a locking surface (65) which is shaped to cooperate with the inner locking surface (45) in the tongue groove (36) of an adjacent floor plate, the two floor plates (1, 1') being mechanically connected, as that their front sides (4a, 4b) are positioned in the same surface plane (HP) and meet at the coupling plane (VP) directed perpendicular thereto, characterized by: - at least the main part of the bottom end (48) of the tongue groove, seen parallel to the surface plane (HP) , is positioned further away from the coupling plane (VP) than the outer end (69) of the tongue (38), - the inner locking surface (45) of the tongue groove (36) is formed on the upper lip (39) within the notched part (35) of the tongue groove for cooperation with the corresponding locking surface (65) of the tongue (38), which locking surface is formed on the upward part (8) of the tongue (38) to prevent two mechanically connected plates from being pulled apart in a direction D2 perpendicular to the connection plane (VP), - the lower lip (40) has a supporting surface (50) for cooperation with a corresponding supporting surface (71) on the tongue (38) at a distance from the bottom end (48) of the incised groove, the purpose of the supporting surface being to cooperate to counteract a relative displacement of two mechanically coupled plates in a direction (Dl) perpendicular to the surface plane (HP), - that all parts of the parts of the lower lip (40) which are connected to the core, seen from the point (C) where the surface plane (HP) and the connection plane (VP) cross, lie outside a plane (LP2) which is further away from said point, than a locking plane (LP1) which is parallel thereto and which is tangent to the cooperating locking surfaces (45, 65) of the tongue groove (36) and the tongue (38) where the locking surfaces are most angled relative to the surface plane (HP ), and - the upper (39) and lower (40) lips and the tongue (38) of the ing edge parts (4a, 4b) are designed to enable disconnection of two mechanically coupled floor plates by upward rotation of one floor plate relative to the other about a center of rotation (C) near a point of intersection between the surface plane (HP) and the coupling plane (VP) for disconnection of the tongue (38) of one floor plate (1') and the tongue groove (36) of the other floor plate (1).