NZ527354A

NZ527354A - Floorboards and methods for production and installation thereof

Info

Publication number: NZ527354A
Application number: NZ527354A
Authority: NZ
Inventors: Darko Pervan
Original assignee: Valinge Aluminium Ab
Priority date: 2001-01-12
Filing date: 2002-01-14
Publication date: 2004-09-24
Also published as: ES2291467T3; RU2277159C2; DE60224499D1; ATE383480T1; CA2433487C; RU2003124758A; JP4405149B2; SI1349995T1; PL202339B1; PT1349994E; BR0206563A; DE60224499T2; CA2434168C; NO20032688L; NO327717B1; AU2002217740C1; DK1349994T3; NO20032687D0; KR20030094234A; DE60224499T3

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

<div class="application article clearfix" id="description"> WO 02/055810 527354 PCT/SE02/00043 FLOORBOARDS AND METHODS FOR PRODUCTION AND INSTALLATION THEREOF The present invention relates to a locking system for mechanical joining of floorboards, floorboards having such a locking system, a method of installing these floorboards, a method of producing them, a tool as well 5 as use of such a tool for installation of floorboards. Technical Field The invention is particularly suited for floorboards which are based on wood material and in the normal case have a core of wood and which are intended to be mecha-10 nically joined. The following description of prior-art technique and the objects and features of the invention will therefore be directed at this field of application and, above all, rectangular parquet floors which are joined on long side as well as short side. The invention 15 is particularly suited for floating floors, i.e. floors that can move in relation to the base. However, it should be emphasised that the invention can be used on all types of existing hard floors, such as homogeneous wooden floors, wooden floors with a lamellar core or plywood 2 0 core, floors with a surface of veneer and a core of wood fibre, thin laminate floors, floors with a plastic core and the like. The invention can, of course, also be used in other types of floorboards which can be machined with cutting tools, such as subfloors of plywood or particle 25 board. Even if it is not preferred, the floorboards can after installation be fixed to the base. Technical Background of the Invention Mechanical joints have in a short time taken great market shares mainly owing to their superior laying pro- 3 0 perties, joint strength and joint quality. Even if the floor according" to WO 9426999 as described in more detail below and the floor marketed under the trademark Alloc® WO 02/055810 PCT/SE02/00043 2 have great advantages compared with traditional, glued floors, further improvements are, however, desirable. Mechanical joint systems are very convenient for joining not only of laminate floors but also wooden 5 floors and composite floors. Such floorboards may consist of a large number of different materials in the surface, core and rear side. As will be described below, these materials can also be included in the different parts of the joint system, such as strip, locking element and 10 tongue. A solution involving an integrated strip which is formed according to, for example, WO 9426999 or WO 9747 834 and which provides the horizontal joint, and also involving a tongue which provides the vertical joint, results, however, in costs in the form of material 15- waste in connection with the forming of the mechanical joint by machining of the board material. For optimal function, for instance a 15-mm-thick parquet floor should have a strip which is of a width which is approximately the same as the thickness of the 20 floor, i.e. about 15 mm. With a tongue of about 3 mm, the amount of waste will be 18 mm. The floorboard has a normal width of about 200 mm. Therefore the amount of material waste will be about 9%. In general, the cost of material waste will be great if the floorboards consist 25 of expensive materials, if they are thick or if their format is small, so that the number of running meters of joint per square meter of floor will be great. Certainly the amount of material waste can be reduced if a strip is used which is in the form of a separate-3 0 ly manufactured aluminium strip which is already fixed to the floorboard at the factory. Moreover, the aluminium strip can in a number of applications result in a better and also more inexpensive joint system than a strip machined and formed from the core. However, the aluminium 3 5 strip is disadvantageous since the investment cost can be considerable and extensive reconstruction of the factory may be necessary to convert an existing traditional pro- WO 02/055810 PCT/SE02/00043 3 duction line so that floorboards with such a mechanical joint system can be produced. An advantage of the prior-art aluminium strip is, however, that the starting format of the floorboards need not be changed. 5 When a strip produced by machining of the floorboard material is involved, the reverse is the case. Thus, the format of the floorboards must be adjusted so that there is enough material for forming the strip and the tongue. For laminate floors, it is often necessary to change also 10 the width of the decorative paper used. All these adjustments and changes also require costly modifications of production equipment and great product adaptations. In addition to the above problems relating to undesirable material waste and costs of production and 15 product adaptation, the strip has disadvantages in the form of its being sensitive to damage during transport and installation. To sum up, there is a great need of providing a mechanical joint at a lower production cost while at the 2 0 same time the aim is to maintain the present excellent properties as regards laying, taking-up, joint quality and strength. With prior-art solutions, it is not possible to obtain a low cost without also having to lower the standards of strength and/or laying function. An 25 object of the invention therefore is to indicate solutions which aim at reducing the cost while at the same time strength and function are retained. The invention starts from known floorboards which have a core, a front side, a rear side and opposite joint 3 0 edge portions, of which one is formed as a tongue groove defined by upper and lower lips and having a bottom end, and the other is formed as a tongue with an upwardly directed portion at its free outer end. The tongue groove has the shape of an undercut groove with an opening, an 35 inner portion and an inner locking surface. At least parts of the lower lip are formed integrally with the core of the floorboard and the tongue has a locking sur WO 02/055810 PCT/SE02/00043 4 face which is designed to coact with the inner locking surface in the tongue groove of an adjoining floorboard, when two such floorboards are mechanically joined, so that their front sides are located in the same surface 5 plane (HP) and meet at a joint plane (VP) directed perpendicular thereto. This technique is disclosed in, inter alia DE-A-3041781, which will be discussed in more detail below. Before that, however, the general technique regard-10 ing floorboards and locking systems for mechanical lock-, ing-together of floorboards will be described as a background of the present invention. Description of Prior Art To facilitate the understanding and description of 15 the present invention as well as the knowledge of the problems behind the invention, here follows a description of both the basic construction and the function of floorboards according to WO 9426999 and WO 9966151, with reference to Figs 1-17 in the accompanying drawings. In 2 0 applicable parts, the following description of the prior-art technique also applies to the embodiments of the present invention as described below. Figs 3a and 3b show a floorboard 1 according to WO 9426999 from above and from below, respectively. The 25 board 1 is rectangular with an upper side 2, an underside 3, two opposite long sides with joint edge portions 4a and 4b, and two opposite short sides with joint edge portions 5a and 5b. The joint edge portions 4a, 4b of the long sides as 30 well as the joint edge portions 5a, 5b of the short sides can be joined mechanically without glue in a direction D2 in Fig. lc, so as to meet in a joint plane VP (marked in Fig. 2c) and so as to have, in their laid state, their upper sides in a common surface plane HP (marked in 35 Fig. 2c). In the shown embodiment, which is an example of floorboards according to WO 9426999 (Figs 1-3 in the WO 02/055810 PCT/SE02/00043 5 accompanying drawings), the board 1 has a factory-mounted plane strip 6 which extends along the entire long side 4a and which is made of a flexible, resilient aluminium sheet. The strip 6 extends outwards beyond the joint 5 plane VP at the joint edge portion 4a. The strip 6 can be attached mechanically according to the shown embodiment or else by glue or in some other manner. As stated in said documents, it is possible to use as material for a strip that is attached to the floorboard at the factory, 10 also other strip materials, such as sheet of some other metal, aluminium or plastic sections. As is also stated in WO 9426999 and as described and shown in WO 9966151, the strip 6 can instead be formed integrally with the board 1, for instance by suitable machining of the core 15 of the board 1. The present invention is usable for floorboards where the strip or at least part thereof is integrally formed with the core, and the invention solves special problems that arise in such floorboards and the produc-20 tion thereof. The core of the floorboard need not, but is preferably, made of a uniform material. The strip 6, however, is always integrated with the board 1, i.e. it should be formed on the board or be factory-mounted. In known embodiments according to the above-mention-25 ed WO 9426999 and WO 9966151, the width of the strip 6 can be about 3 0 mm and the thickness about 0.5 mm. A similar, although shorter strip 6' is arranged along one short side 5a of the board 1. The part of the strip 6 projecting beyond the joint plane VP is formed 30 with a locking element 8 which extends along the entire strip 6. The locking element 8 has in its lower part an operative locking surface 10 facing the joint plane VP and having a height of, for instance, 0.5 mm. In laying, this locking surface 10 coacts with a locking groove 14 35 which is made in the underside 3 of the joint edge portion 4b of the opposite long side of an adjoining board 1'. The strip 6' along the short side is provided with a WO 02/055810 PCT/SE02/00043 6 corresponding locking element 8', and the joint edge portion 5b of the opposite short side has a corresponding locking groove 14'. The edge of the locking grooves 14, 14' facing away from the joint plane VP forms an opera-5 tive locking surface 10' for coaction with the operative locking surface 10 of the locking element. For mechanical joining of long sides as well as short sides also in the vertical direction (direction D1 in Fig. lc), the board 1 is also along its one long 10 side (joint edge portion 4a) and its one short side (joint edge portion 5a) formed with a laterally open recess or tongue groove 16. This is defined upwards by an upper lip at the joint edge portion 4a, 5a and downwards by the respective strips 6, 6'. At the opposite edge por-15 tions 4b, 5b, there is an upper recess 18 which defines a locking tongue 20 coacting with the recess or tongue groove 16 (see Fig. 2a). Figs la-lc show how two long sides 4a, 4b of two such boards 1, 1' on a base U can be joined with each 20 other by downward angling by pivoting about a centre C close to the intersection between the surface plane HP and the joint plane VP, while the boards are held essentially in contact with each other. Figs 2a-2c show how the short sides 5a, 5b of the 25 boards 1, 1' can be joined together by snap action. The long sides 4a, 4b can be joined by means of both methods, whereas the joining of the short sides 5a, 5b - after laying of the first row of floorboards - is normally carried out merely by snap action after the long sides 4a, 3 0 4b have first been joined. When a new board 1' and a previously laid board 1 are to be joined along their long side edge portions 4a, 4b according to Figs la-lc, the long side edge portion 4b of the new board 1' is pressed against the long side edge 35 portion 4a of the previously laid board 1 according to Fig. la, so that the locking tongue 20 is inserted into the recess or tongue groove 16. The board 1' is then WO 02/055810 PCT/SE02/00043 7 angled down towards the subfloor U according to Fig. lb. The locking tongue 2 0 enters completely the recess or tongue groove 16 while at the same time the locking element 8 of the strip 6 snaps into the locking groove 14. 5 During this downward angling, the upper part 9 of the locking element 8 can be operative and perform guiding of the new board 1' towards the previously laid board 1. In their joined position according to Fig. lc, the boards 1, l' are certainly locked in the D1 direction as 10 well as the D2 direction along their long side edge portions 4a, 4b, but the boards 1, 1' can be displaced relative to each other in the longitudinal direction of the joint along the long sides (i.e. direction D3). Figs 2a-2c show how the short side edge portions 5a 15 and 5b of the boards 1, 1' can be joined mechanically in the D1 as well as the D2 direction by the new board 1' being displaced essentially horizontally towards the previously laid board 1. This can in particular be carried out after the long side of the new board 1' has been 2 0 joined, by inward angling according to Figs la-c, with a previously laid board 1 in an adjoining row. In the first step in Fig. 2a, bevelled surfaces of the recess 16 and the locking tongue 2 0 cooperate so that the strip 6' is forced downwards as a direct consequence of the 25 bringing-together of the short side edge portions 5a, 5b. During the final bringing-together, the strip 6' snaps up when 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' 3 0 engage each other. By repeating the operations shown in Figs la-c and 2a-c, the entire floor can be laid without glue and along all joint edges. Thus, prior-art floorboards of the above type can be joined mechanically by first, as a rule, 3 5 being angled downwards on the' long side and by the short sides, when the long side has been locked, being snapped together by horizontal displacement of the new board 1' WO 02/055810 PCT/SE02/00043 8 along the long side of the previously laid board 1 (direction D3). The boards 1, 1' can, without the joint being damaged, be taken up again in reverse order of laying and then be laid once more. Parts of these laying 5 principles are applicable also in connection with the present invention. To function optimally and to allow easy laying and taking-up again, the prior-art boards should, after being joined, along their long sides be able to take a position 10 where there is a possibility of a minor play between the operative locking surface 10 of the locking element and the operative locking surface 10' of the locking groove 14. However, no play is necessary in the actual butt joint between the boards in the joint plane VP close to 15 the upper side of the boards (i.e. in the surface plane HP) . For such a position to be taken, it may be necessary to press one board against the other. A more detailed description of this play is to be found in WO 9426999. Such a play can be in the order of 0.01-0.05 mm between 20 the operative locking surfaces 10, 10' when pressing the long sides of adjoining boards against each other. This play facilitates entering of the locking element 8 in the locking groove 14, 14' and its leaving the same. As mentioned, however, no play is required in the joint between 25 the boards, where the surface plane HP and the joint plane VP intersect at the upper side of the floorboards. The joint system enables displacement along the joint edge in the locked position after joining of an optional side. Therefore laying can take place in many 30 different ways which are all variants of the three basic methods: > Angling of long side and snapping in of short side. > Snapping in of long side - snapping in of short side > Angling of short side, upward angling of two boards, 35 displacement of the new board along the short side edge of the previous board and, finally, downward angling of two boards. WO 02/055810 PCT/SE02/00043 9 The most common and safest laying method is that the long side is first angled downwards and locked against . another floorboard. Subsequently, a displacement in the locked position takes place towards the short side of 5 a third floorboard, so that the snapping-in of the short side can take place. Laying can also be made by one side, long side or short side, being snapped together with another board. Then a displacement in the locked position takes place until the other side snaps together with a 10 third board. These two methods require snapping-in of at least one side. However, laying can also take place without snap action. The third alternative is that the short side of a first board is angled inwards first towards the short side of a second board, which is already joined on 15 its long side with a third board. After this joining-together, the first and the second board are slightly angled upwards. The first board is displaced in the upwardly angled position along its short side until the upper joint edges of the first and the third board are 2 0 in contact with each other, after which the two boards are jointly angled downwards. The above-described floorboard and its locking system have been very successful on the market in connection with laminate floors which have a thickness of about 7 mm 25 and an aluminium strip 6 having a thickness of about 0.6 mm. Similarly, commercial variants of the floorboards according to WO 9966151 shown in Figs 4a and 4b have been successful. However, it has been found that this technique is not particularly suited for floorboards that 3 0 are made of wood-fibre-based material, especially massive wood material or glued laminated wooden material, to form parquet floors. One reason why this known technique is not suited for this type of products is the large amount of material waste that arises owing to the machining of 35 the edge portions to form a tongue groove having the necessary depth. WO 02/055810 PCT/SE02/00043 10 To partly cope with this problem, it would be possible to use the technique which is shown in Figs 5a and 5b in the accompanying drawings and which is described and shown in DE-A-3343601, i.e. it would be possible to 5 form both joint edge portions of separate elements which are attached to the long side edges. Also this technique results in high costs of aluminium sections and of the considerable machining that is required. Moreover, it is difficult to attach the sectional elements along the 10 edges in a cost-efficient manner. However, the shown geometry does not allow mounting and dismounting without considerable play by downward and upward angling, respectively, since the components do not go clear of each other during these movements if they are manufac-15 tured with a close fit (see ,Fig. 5b). Another known design of floorboards with a mechanical locking system is shown in Figs 6a-d in the accompanying drawings and is described and shown in CA-A-0991373. When using this mechanical locking system, all 2 0 forces striving to pull the long sides of the boards apart are taken up by the locking element at the outer end of the strip (see Fig. 6a). When laying and taking up the floor, the material must be flexible to allow the tongue to be released by rotation about two centres at 25 the same time. A tight fit between all surfaces makes rational manufacture and displacement in the locked position impossible. The short side 6c has no horizontal lock. This type of mechanical lock, however, causes a large amount of material waste owing to the design of the 30 large locking elements. One more known design of mechanical locking systems for boards is shown in GB-A-1430429 and Figs 7a-7b in the accompanying drawings. This system is basically a tongue-and-groove joint which is provided with an extra holding 35 hook on an extended lip on one side of the tongue groove and which has a corresponding holding ridge formed on the upper side of the tongue. The system requires consider- WO 02/055810 PCT/SE02/00043 11 able elasticity of the lip provided with the hook, and dismounting cannot take place without destroying the joint edges of the boards. A tight fit makes manufacture difficult and the geometry of the joint causes a large 5 amount of material waste. Another known design of mechanical locking systems for floorboards is disclosed in DE-A-4242530. Such a locking system is also shown in Figs 8a-b in the accompanying drawings. This known locking system suffers from 10 several drawbacks. Not only does it cause a large amount of material waste in manufacture, it is also difficult to produce in an efficient manner if high-quality joints in a high-quality floor are desired. The undercut groove forming the tongue groove can only be made by using a 15 shank-end mill which is moved along the joint edge. It is thus not possible to use large disk-shaped cutting tools to machine the board from the side edge. For mechanical joining of different types of boards, in particular floorboards, there are many suggestions, in 20 which the amount of material waste is small and in which production can take place in an efficient manner also when using wood-fibre- and wood-based board materials. Thus, WO 9627721 (Figs 9a—b in the accompanying drawings) and JP 3169967 (Figs lOa-b in the accompanying drawings) 25 disclose two types of snap joints which produce a small amount of waste but which have the drawback that they do not allow dismounting of the floorboards by upward angling. It is true that these joint systems can be made in an efficient manner using large disk-shaped cutting 3 0 tools, but they have the serious drawback that dismounting by upward angling would cause so serious damage to the locking system that the boards could not be laid once more by mechanical locking. Another known system is disclosed in DE-A-1212275 35 and shown in Figs lla-b in the accompanying drawings. This known system is suited for sports floors of plastic material and cannot be manufactured by means of large WO 02/055810 PCT/SE02/00043 12 disk-shaped cutting tools for forming the sharply undercut groove. Also this known system cannot be dismounted by upward angling without the material having so great elasticity that the upper and lower lips round the under-5 cut groove are greatly deformed while being pulled apart. This type of joint is therefore not suited for floorboards that are based on wood-fibre-based material, if high-quality joints are desired. Tongue-and-groove joints having an inclined groove 10 and tongue have also been suggested according to US-A-1124228. The type of joint which is shown in Figs 12c-d in the accompanying drawings, makes it possible to mount a new board by pushing it down over the obliquely upwardly directed tongue on the previously laid board. To 15 secure the newly laid board, use is made of nails which' are driven obliquely down thrpugh the board above the obliquely upwardly directed tongue. In the embodiment according to Figs 12a-b, this technique cannot be used since a dovetail joint is used. This technique certainly 2 0 causes a small amount of material waste but is not at all suitable if a floating floor is to be provided, with individual floorboards which, without being damaged, are to be mounted and dismounted in a simple manner and which have high-quality joints. 25 DE-A-3041781 discloses and shows a locking system for joining of boards, especially for making roller-skating rings and bowling alleys of plastic material. Such a joint system is also shown in Figs 13a-d in the accompanying drawings. This system comprises an undercut 30 longitudinal groove along one edge of the board and a projecting upwardly bent tongue along the opposite edge of the board. In cross-section, the undercut groove has a first portion which is defined by parallel surface portions and is parallel with the principal plane of the 35 board, and a second interior portion which is trapezoidal or semi-trapezoidal (Figs 13a-b and Figs 13c-d, respectively, in the accompanying drawings). In cross-section, WO 02/055810 PCT/SE02/00043 13 the tongue has two plane-parallel portions angled relative to each other, where the portion closest to the centre of the board is parallel with the principal plane of the board and where the outer free portion is angled in 5 the upward direction in correspondence with the corresponding surface portion within the trapezoidal part of the undercut groove. The design of the tongue and groove as well as the edge portions of the board is such that when two such 10 boards are mechanically joined, engagement is obtained between on the one hand the surface portions of the tongue and corresponding surface portions of the undercut groove along the entire upper side and outer end of the tongue as well as along the underside of the inner plane-15 parallel portion of the tongue and, on the other hand, between the edge surfaces of the joined boards above and below the tongue and the groove, respectively. When a new board is to be joined with a previously laid board, the new board is angled upwards at a suitable angle for 20 insertion of the angled outer portion of the tongue into the outer plane-parallel part of the groove in the previously laid board. Subsequently the tongue is inserted into the groove while the new board is being angled downwards. Owing to the angular shape of the tongue, a con-25 siderable amount of play is necessary in the first part of the groove to allow this insertion and inward angling to be carried out. Alternatively, a considerable degree of elasticity of the floor material is necessary, which according to the document should consist of plastic mate-30 rial. In the laid joined position, there is engagement between the major part of the surfaces of tp.e tongue and the undercut groove except below the upwardly angled outer portion of the tongue. A serious drawback of the mechanical locking system 35 according to DE-A-3041781 is that it is difficult to produce. As production method, it is suggested to use a mushroom-type shank end mill with an outer portion which WO 02/055810 PCT/SE02/00043 14 generates the cross-sectionally trapezoidal inner part of the tongue groove. Such a production method is not particularly rational and besides causes great tolerance problems if the production method should be used for produc-5 ing floorboards or other boards of wood material for forming wall panels or parquet floorboards having high-quality joints. As mentioned above, a drawback of this prior-art mechanical locking system is that the insertion of the 10 angled tongue into the groove requires a considerable amount of play between tongue and groove (see Fig. 5 in DE-A-3 041781 and Fig. 13b in the accompanying drawings) for downward angling to take place, if there is not a considerable degree of elasticity in the board material. 15 Moreover, such downward angling cannot be carried out while the new board and the previously laid board are brought together in such manner that they touch each other close to the upper edge of the boards above the tongue and groove respectively, so that the pivoting 20 centre of the downward angling motion is positioned at this point. One more drawback of this prior-art mechanical locking system according to DE-A-3 041781 in connection with fairly thick boards of wood material is that a 25 displacement of the new board along the previously laid board in the laid or partly raised position is made much more difficult by the boards engaging with each other along large surface portions. Even if the machining of wooden boards or boards based on wood fibre would be 30 carried out very accurately, these surface portions are for natural reasons not quite smooth but have projecting fibres, which significantly increase friction. When laying parquet floors or the like, long boards (frequently 2-2.4-m-long and 0.2-0.4-m-wide boards) and essentially 35 natural materials are involved. This type of long boards warp and will therefore often deviate from a completely float shape (they have "banana" shape). In those cases, WO 02/055810 PCT/SE02/00043 15 it will be still more difficult to displace a newly laid board along a previously laid board, if a mechanical locking-together of the boards also at the short sides is desired. 5 A further drawback of the mechanical locking system according to DE-A-3 041781 is that it is not very suited in connection with high-quality floors which are made of wood materials or wood-fibre-based materials and which therefore require a tight fit in the vertical direction 10 between tongue and groove in order to prevent creaking. WO 9747834 discloses floorboards with different types of mechanical locking systems. The locking systems which are intended for locking together the long sides of the boards (Figs 2-4, 11 and 22-25 in the document) are 15 designed so as to be mounted and dismounted by a connecting and angling movement, while most of those intended for locking together the short sides of the boards (Figs 5-10) are designed so as to be connected to each other by being translatorily pushed towards each other 2 0 for connection by means of a snap lock, but these locking systems at the short sides of the boards cannot be dismounted without being destroyed or, in any case, damaged. Some of the boards that are disclosed in WO 9747834 and that have been designed for connection and dismount-25 ing by an angular motion (Figs 2-4 in WO 9747 834 and Figs 14a-c in the accompanying drawings) , have at their one edge a groove and a strip projecting below the groove and extending beyond a joint plane where the upper sides of two joined boards meet. The strip is designed to coact 30 with an essentially complementarily formed portion on the opposite edge of the board, so that two similar boards can be joined. A common feature of these floorboards is that the upper side of the tongue of the boards and the corresponding upper boundary surface of the groove are 35 plane and parallel with the upper side or surface of the floorboards. The connection of the boards to prevent them from being pulled apart transversely of the joint plane WO 02/055810 PCT/SE02/00043 16 is obtained exclusively by means of 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 suffer from 5 the drawback that they require a strip portion which extends beyond the joint plane, which causes material waste also within the joint edge portion where the groove is formed. WO 9747834 also discloses mechanical joint systems 10 which comprise a circular-arc-shaped tongue and a correspondingly formed groove in the opposite side edge of the floorboard (cf. Figs 14d-14e in the accompanying drawings) . When connecting such locking systems, the tip of the tongue is put towards the opening of the arcuate 15 groove, after which downward angling is begun. In this downward angling, there is a large surface contact between all the arcuate surfaces of tongue and groove. If this type of joint system would be used for long boards of wood or wood-based material, it would be very 2 0 difficult to obtain a smooth and simple bringing together. Moreover, the friction between the arcuate surfaces and between the tip of the tongue and the bottom of the groove would require considerable forces for displacement of one board along another board in their join-25 ed state. This prior-art technique is certainly better than the one disclosed in the above-mentioned DE-A-3041781, but it suffers from many drawbacks of that technique. US-A-274 0167 (see also Figs 15a-b in the accompany- 3 0 ing drawings) discloses parquet boards or squares which are made of wood and which at their opposite edges are formed with edge portions which are hooked into each other when laying several parquet squares in a row. One edge portion has a downwardly directed hook, and the 35 opposite edge portion has an upwardly directed hook. To allow insertion of a new parquet board under a previously laid parquet board, the underside of the upwardly direct WO 02/055810 PCT/SE02/00043 17 ed hook is bevelled. The parquet boards that are joined at a vertical joint plane are secured merely in the horizontal direction transversely of the joint plane. To secure the boards also perpendicular to the upper side of 5 the parquet boards, use is made of a glue layer which has been spread in advance on the base on which the parquet floor is to be arranged. A previously laid parquet board can therefore be raised again merely before the glue layer has bound. In practice this parquet floor is there-10 fore permanently secured to the base after being laid. CA-A-22 52 791 shows and describes floorboards which are formed with a specially designed groove along one long side and a complementarily formed tongue along the other long side. As shown in the patent specification 15 and also in Figs 16a-b in the accompanying drawings, the tongue and groove are rounded and angled obliquely upwards to enable joining of one board with another by the new board being placed close to the laid one and then being simultaneously raised and angled, after which the 20 groove is pulled down over the obliquely upwardly directed tongue during simultaneous bringing together and downward angling. Since tongue and groove are complementarily formed, it is difficult to connect and, optionally, once more pull adjoining floorboards apart. A deviation from 25 the plane form, i.e. the existence of "banana shape", results in a further obstacle to the connecting of two such boards. The risk of damage to the tongue is therefore great, and the design also causes great frictional forces between the surfaces of the tongue and groove. 30 US-A-5797237 discloses a snap lock system for joining parquet boards. In the accompanying drawings, Fig. 17a is a section through two joined boards, while Fig. 17b shows that such a known floorboard cannot be dismounted by the board being angled upwards relative 35 to the remaining, lying floorboard. Instead, as shown in Fig. 4B in the patent specification, both the board that is to be removed and the board to which it is connected WO 02/055810 PCT/SE02/00043 18 and which is to remain, must be lifted up to pull out the tongue from the groove. The system bears great resemblance with that disclosed in the above-mentioned US-A-2740167 (Figs 15a-b in the accompanying drawings) but 5 with the difference that a short lower lip is formed below the upper hook-shaped projection or lip. This short lower lip, however, has no joining effect since there is a gap between the underside of the tongue and the upper side of this short lip when two boards are joined. 10 Besides, this play is necessary for the dismounting method as shown in Fig. 17c. Certainly, it is stated that the joint system is a snap joint, but probably the laid board is angled slightly upwards to let in the tongue under the hook-shaped lip of this board. This mechanical 15 locking system can, as also shown in the patent specification, be manufactured with the aid of large disk-shaped cutting tools. There is no undercut groove, whose upper and lower lips abut against the inserted tongue and lock this both vertically and horizontally, in this locking 20 system. Thus the groove has a larger vertical extent than the corresponding parts of the tongue. The laid floor will therefore be able to move towards and away from the base, which will cause creaking in the joints and unacceptable vertical displacements. Owing to the insuf-25 ficient locking, a high-quality joint cannot be obtained either. FR-A-267 5174 discloses a mechanical joint system for ceramic tiles which have complementarily formed opposite edge portions, in which case use is made of separate 30 spring clips which are mounted at a distance from each other and which are formed to grasp a bead on the edge portion of an adjoining tile. The joint system is not designed for dismounting by pivoting, which is obvious from Fig. 18a and, in particular, Fig. 18b in the accom-3 5 panying drawings. Figs 19a and 19b show floorboards which are formed according to JP 7180333 and are made by extrusion of WO 02/055810 PCT/SE02/00043 19 metal material. After mounting, it is practically impossible to dismount such floorboards owing to the joint geometry, which is evident from Fig. 19b. Finally, Figs 20a and 20b show another known joint 5 system which is disclosed in GB-A-2117813 and which is intended for large insulated wall panels. This system bears great resemblance with the above-mentioned system according to CA-A-2252791 and the system from WO 974-7834 as shown in Figs 14d and 14e in the accompanying draw-10 ings. The system suffers from the same drawbacks as these last-mentioned two systems and is not suited for efficient production of floorboards based on wood material or wood fibre material, especially if high-quality joints in a high-quality floor are desired. The construction 15 according to this GB publication uses metal sections as connecting elements and is not openable by upward angling. Other prior-art systems are disclosed in, for instance, DE 20013380U1, JP 2000179137A, DE 3041781, 20 DE 19925248, DE 20001225, EP 0623724, EP 0976889, EP 1045083. As is evident from that stated above, prior-art systems have both drawbacks and advantages. However, no locking system is quite suited for rational production 25 of floorboards with a locking system which is optimal as regards production technique, waste of material, laying and taking-up function and which besides can be used for floors which are to have high quality, strength and function in their laid state. 30 An object of the present invention is to satisfy this need and provide such an optimal locking system for floorboards and such optimal floorboards. Another object of the invention is to provide a rational method of producing floorboards with such a locking system. One more 35 object of the invention is to provide a new installation method, which allows easier and more rational laying than does prior art. Another object of the invention is to WO 027055810 PCT/SE02/00043 .20 provide a tool to facilitate the laying of.floorboards by upward angling and joining of floorboards. Yet another object of the invention is to provide use of such a tool for laying of floorboards. Each of the above objects is to be read disjunctively with the object of at least providing the public with a useful choice. Further objects of the invention are evident from that stated above as well as from the following description. Summary of the Invention 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 bfe brought 'together and pulled apart by a pivoting motion, which has its centre close to the intersection between the surface planes and the common joint plane of two adjoining floorboards. The undercut in the groove of such a locking system'is made by means of 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. A laying 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 opening of the undercut groove of the previously laid board, angling the new board upwards during simultaneous insertion of the tongue into the undercut groove and simultaneously angling down the new board to the final position. What characterises the locking system, the floorboard and the laying method, according to the invention is, however, stated in the independent claims. The dependent claims define particularly preferred embodiments according to the invention. Further advantages and features of the invention are also evident from the following description. IPONZ - 7 JUL 2004 WO 02/055810 PCT/SE02/00043 21 Before specific and preferred embodiments of the invention will be described with reference to the accompanying drawings, the basic concept of the invention and the strength and function requirements will be described. 5 The invention is applicable to rectangular floor boards having a first pair of parallel sides and a second pair of parallel sides. With a view to simplifying the description, the first pair is below referred to as long sides and the second pair as short sides. It should, how-10 ever, be pointed that the invention is also applicable to boards that can be square. High Joint Quality By high joint quality is meant a tight fit in the locked position between the floorboards both vertically 15 and horizontally. It should be possible to join the floorboards without very large visible gaps or differences in level between the joint edges in the unloaded as well as in the normally loaded state. In a high-quality floor, joint gaps and differences in level should 2 0 not be greater than 0.2 and 0.1 mm respectively. Downward Angling with Rotation at Joint Edge and Guiding As will be evident from the following description, it should be possible to lock at least one side, preferably the long side, by downward angling. The downward 25 angling should be able to take place with a rotation about a centre close to the intersection between the surface planes of the floorboards and the joint plane to be made, i.e. close to the "upper joint edges" of the boards when contacting each other. Otherwise, it is not 3 0 possible to make a joint which in the locked position has tight joint edges. It should be possible to terminate the rotation in a horizontal position, in which the floorboards are locked vertically without any play, since a play may cause 35 undesirable differences in level between the joint edges. Inward angling should also take place in a manner that simultaneously guides the floorboards towards each other WO 02/055810 PCT/SE02/00043 22 with tight joint edges and straightens out any banana shape (i.e. deviation from a straight flat shape of the floorboard). The locking element and the locking groove should have guiding means which coact with each other 5 during inward angling. The downward angling should take place with great safety without the boards getting stuck and pinching each other so as to cause a risk of the locking system being damaged. Upward Angling about Joint Edge 10 It should be possible to angle the long side upwards so that the floorboards can be released. Since the boards in the starting position are joined with tight joint edges, this upward angling must thus also be able to take place with upper joint edges in contact with each other 15 and with rotation at the joint edge. This possibility of upward angling is very important not only when changing floorboards or moving a floor. Many floorboards are trial-laid or laid incorrectly adjacent to doors, in corners etc. during installation. It is a serious draw-20 back if the floorboard cannot be easily released without the joint system being damaged. Nor is it always the case that a board that can be angled inwards can also be angled up again. In connection with the downward angling, a slight downwards bending of the strip usually takes 25 place, so that the locking element is bent backwards and downwards and opens. If the joint system is not formed with suitable angles and radii, the board can after laying be locked in such manner that taking up is not possible. The short side can, after the joint of the long 3 0 side has been opened by upward angling, usually be pulled out along the joint edge, but it is advantageous if also the short side can be opened by upward angling. This is particularly advantageous when the boards are long, for instance 2.4 m, which makes pulling out of short sides 35 difficult. The upward angling should take place with. great safety without the boards getting stuck and pinch- WO 02/055810 PCT/SE02/00043 23 ing each other so as to cause a risk of the locking system being damaged. Snapping-in It should possible to lock the short sides by hori-5 zontal snapping-in. This requires that parts of the joint system be flexible and bendable. Even if inward angling of long sides is much easier and quicker than snapping-in, it is an advantage if also the long side can be snapped in, since certain laying operations, for instance 10 round doors, require that the boards be joined horizontally. Coat of Material at Long and Short Side If the floorboard is, for instance, 1.2*0.2 m, each square meter of floor surface will have about six times 15 more long side joints than short side joints. A large amount of material waste and expensive joint materials are therefore of less importance on short side than on long side. ;Horizontal Strength ;2 0 For high strength to be achieved, the locking ele ment must as a rule have a high locking angle, so that the locking element does not snap out. The locking element must be high and wide so that it does not break when subjected to high tensile load as the floor shrinks in 25 winter owing to the low relative humidity at this time of the year. This also applies to the material closest to the locking groove in the other board. The short side joint should have higher strength than the long side joint since the tensile load during shrinking in winter ;3 0 is distributed over a shorter joint length along the short side than along the long side. ;Vertical Strength It should be possible to keep the boards plane when subjected to vertical loads. Moreover, motion in the 35 joint should be avoided since surfaces that are subjected to pressure and that move relative to each other, for instance upper joint edges, may cause creaking. ;WO 02/055810 PCT/SE02/00043 ;24 ;Displaceability ;To make it possible to lock all four sides, it must be possible for a newly laid board to be displaced in the locked position along a previously laid board. This 5 should take place using a reasonable amount of force, for instance by driving together using a block and hammer, without the joint edges being damaged and without the joint system having to be formed with visible play horizontally and vertically. Displaceability is more impor-10 tant on long side than on short side since the friction is there essentially greater owing to a longer joint. ;Production ;It should be possible to produce the joint system rationally using large rotating cutting tools having 15 extremely good accuracy and capacity. ;Measuring ;A good function, production tolerance and quality require that the joint profile can be measured continuously and checked. The critical parts in a mechanical 20 joint system should be designed in such manner that production and measurement are facilitated. It should be possible to produce them with tolerances of a few hundredths of a millimetre, and it should therefore be possible to measure them with great accuracy, for 25 instance in a so-called profile projector. If the joint system is produced with-linear cutting machining, the joint system will, except for certain production tolerances, have the same profile over the entire edge portion. Therefore the joint system can be measured with 30 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, however, requires that the joint system can also be measured quickly and easily without destructive methods, 35 for instance using gages. This is facilitated if the critical parts in the locking system are as' few as possible. ;WO 02/055810 PCT/SE02/00043 ;25 ;Optimisation of Long and Short Side For a floorboard to be manufactured optimally at a minimum cost, long and short side should be optimised in view of their different properties as stated above. For 5 instance, the long side should be optimised for downward angling, upward angling, positioning and displaceability, while the short side should be optimised for snapping-in and high strength. An optimally designed floorboard should thus have different joint systems on long and 10 short side. ;Possibility of Moving Transversely of Joint Edge Wood-based floorboards and floorboards in general which contain wood fibre swell and shrink as the relative humidity changes. Swelling and shrinking usually start 15 from above, and the surface layers can therefore move to a greater extent than the core, i.e. the part of which the joint system is formed. To prevent the upper joint edges from rising or being crushed in case of a high degree of swelling, or joint gaps from arising when 2 0 drying up, the joint system should be constructed so as to allow motion that compensates for swelling and shrinking . ;Drawbacks of Prior-Art Systems Figs 4a and 4b show prior-art systems of the type 25 Alloc® original and Alloc®Home with a projecting strip that can be angled and snapped together. ;Prior-art joint systems according to Figs 9-16 can produce a mechanical joint with less waste than mechanical locking systems having a projecting and machined 30 strip. However, all of them do not satisfy the above- ;mentioned requirements and do not solve the problems that the present invention intends to solve. ;The snap joints according to Figs 7, 9, 10, 11, 12, 18, 19 cannot be locked or opened by a pivoting motion 35 round the upper part of the joint edge, and the joints according to Figs 8, 11, 19 cannot be produced rationally ;WO 02/055810 ;PCT/SE02/00043 ;26 ;by machining of board materials with a rotating cutting tool that has a large tool diameter. ;Floorboards according to Figs 12a-b cannot be angled or snapped but must first be inserted by being pushed in 5 parallel with the joint edge. The joint according to Figs 12c-d cannot be snapped. It may possibly be angled inward, but in that case it must be produced with too great a play in the joint system. The strength in the vertical direction is low since upper and lower engaging 10 surfaces are parallel. The joint is also difficult to produce and to displace in the locked position since it does not contain any free surfaces. Moreover, nailing to the base is suggested, using nails which are driven obliquely into the floorboard above the tongue directed 15 obliquely upwards. ;The joint systems according to Figs 6c-d, 15a~b and 17a-b are examples of joints that have no vertical lock, i.e. allow movements perpendicular to the upper side of the boards. ;2 0 The inward angling joint according to Figs 14d-e has a number of drawbacks because it is manufactured and constructed according to the principle that it should have a tight fit and that upper and lower parts of the tongue and groove follow circular arcs having their centre at 25 the upper joint edge, i.e. in the intersection between the joint and surface planes. This joint does not have the necessary guiding parts, and the joint is difficult to angle together since it has an incorrect design and too large engaging surfaces. As a result, it pinches and ;3 0 suffers from the so-called drawer effect during inward angling. The strength in the horizontal direction is too low, which depends on a low upper locking angle and too small angular difference between the upper and lower engaging surfaces. Moreover, the front and upper upwardly 35 angled part of the tongue groove is too small to manage the forces that are required for a high-quality joint system. The too large contact surfaces between tongue and ;WO 02/055810 ;PCT/SE02/00043 ;27 ;groove, the absence of the necessary free surfaces without contact and the requirement for a tight fit in the entire joint make lateral displacement of the floorboard along the joint edge considerably more 5 difficult and also renders rational production with the possibility of achieving good tolerances difficult. Nor can it be snapped together horizontally. ;The joint system according to Figs 16a-b has a design that does not allow it to be angled together with-10 out a considerable degree of material deformation, which is difficult to achieve in normal board materials that are suitable for floors. Also in this case, all parts of the tongue and groove are in contact with each other. This makes lateral displacement of a board in the locked 15 position difficult or impossible. Nor is rational machining possible owing to the fact all surfaces are in contact with each other. Snapping cannot be carried out either. ;The joint system according to Figs 6a-b cannot be 2 0 angled together since it is constructed to move about two pivoting centres simultaneously. It has no horizontal lock in the tongue groove. All surfaces are in contact with each other with a tight fit. In practice, the joint system cannot be displaced and manufactured rationally. 25 It is intended for use with a locking system which is shown in Figs 6c-d and is formed on the adjoining perpendicularly set edge of the board and which does not require lateral displacement for connecting purposes. ;The joint system according to Figs 8a-b have a 30 tongue groove which cannot be manufactured with rotating cutting tools having a large tool diameter. It cannot snap and is constructed to prevent, by initial stress and a tight fit adjacent to the outer vertical part of the strip, lateral displacement. ;35 The joint system according to Figs 5a-b comprises two aluminium sections. Production with rotating cutting tools with a large tool diameter for forming the tongue ;WO 02/055810 PCT/SE02/00043 ;28 ;groove is not feasible. The joint system is formed so that it is impossible to angle a new board inwards by its upper joint edge being held in contact with the upper joint edge of the previously laid board, so that 5 the inward angling takes place about a pivoting centre at the intersection between joint plane and surface plane. To allow inward angling when using this prior-art system, it is necessary to have a considerable play that exceeds what is acceptable in normal floorboards where 10 high-quality, esthetically good joints are required. The joint system according to Figs 13a-d is difficult to manufacture since it requires contact over a large surface part of the outer part of the tongue and the tongue groove. This also makes lateral displacement in the lock-15 ed position difficult. The joint geometry makes upward angling about the upper joint edge impossible. ;The Invention The invention is based on a first understanding that by using suitable production methods, essentially 20 by machining and using tools whose tool diameter significantly exceeds the thickness of the board, it is possible to form advanced shapes rationally with great accuracy of wood materials, wood-based boards and plastic materials, and that this type of machining can be made 25 in a tongue groove at a distance from the joint plane. ;Thus, the shape of the joint system should be adapted to rational production which should be able to take place with very narrow tolerances. Such an adaptation, however, is not allowed to take place at the expense of other 3 0 important properties of the floorboard and the locking system. ;The invention is also based on a second understanding, which is based on the knowledge of the requirements that must be satisfied by a mechanical joint sys-35 tem for optimal function. This understanding has made it possible to satisfy these requirements in a manner that has previously not been known, viz. by a combination of ;WO 02/055810 ;PCT/SE02/00043 ;29 ;a) the design of the joint system with, for instance, specific angles, radii, play, free surfaces and ratios between the different parts of the system, and b) optimal utilisation of the material properties of the core or 5 core, such as compression, elongation, bending, tensile strength and compressive strength. ;The invention is further based on a third understanding that it is possible to provide a joint system at a lower production cost while at the same time func-10 tion and strength can be retained or even, in some cases, be improved by a combination of manufacturing technique, joint design, choice of materials and optimisation of long and short sides. ;The invention is based on a fourth understanding 15 that the joint system, the manufacturing technique and the measuring technique must be developed and adjusted so that the critical parts requiring narrow tolerances should, to the greatest possible extent, be as few as possible and also be designed so as to allow measuring 20 and checking in continuous production. ;According to a first aspect of the invention, there are thus provided a locking system and a floorboard with such a locking system for mechanical joining of all four sides of this floorboard in a first vertical direction 25 Dl, a second horizontal direction D2 and a third direction D3 perpendicular to the second horizontal direction, with corresponding sides of other floorboards with identical locking systems. ;The floorboards can on two sides have a disconnect-3 0 ible mechanical joint system, which is of a known type and which can be laterally displaced in the locked position and locked by inward angling about the upper joint edges or by horizontal snapping. The floorboards have, on the other two sides, a locking system according to the 35 invention. The floorboards can also have a locking system according to the invention on all four sides. ;WO 02/055810 ;PCT/SE02/00043 ;30 ;At least two opposite sides of the floorboard thus have a joint system which is designed according to the invention and which comprises a tongue and a tongue groove defined by upper and lower lips, where the tongue 5 in its outer and upper part has an upwardly directed part and where the tongue groove in its inner and upper part has an undercut. The upwardly directed part of the tongue and the undercut of the tongue groove in the upper lip have locking surfaces that counteract and prevent hori-10 zontal separation in a direction D2 transversely of the joint plane. The tongue and the tongue groove also have coacting supporting surfaces which prevent vertical separation in a direction D1 parallel with the joint plane. Such supporting surfaces are to be found at least in the 15 bottom part of the tongue and on the lower lip of the tongue groove. In the upper part, the coacting locking surfaces can serve as upper supporting surfaces, but the upper lip of the tongue groove and the tongue can advantageously also have separate upper supporting surfaces. 20 The tongue, the tongue groove, the locking element and the undercut are designed so that they can be manufactured by machining using tools which have a greater tool diameter than the thickness of the floorboard. The tongue can with its upwardly directed portion be inserted into 25 the tongue groove and its undercut by an inward angling motion with its centre of rotation close to the intersection between the joint plane and the surface plane, and the tongue can also leave the tongue groove if the floorboard is pivoted or angled upwards with its upper 3 0 joint edge in contact with the upper joint edge of an adjoining floorboard. For the purpose of facilitating production, measurement, inward angling, upward angling and lateral displacement in the longitudinal direction of the joint and counteracting creaking and reducing any 35 problems owing to swelling/shrinking of the floor material, the joint system is formed with surfaces which are ;WO 02/055810 PCT/SE02/00043 ;31 ;not in contact with each other both during inward angling and in the locked position. ;According to a second aspect of the invention, the floorboard has two edge portions with a joint system 5 according to the invention, where the tongue with its upwardly directed portion both can be inserted into the tongue groove and its undercut and can leave the tongue groove by downward angling and upward angling, respectively, by the boards being kept in contact with each 10 other with their upper joint edges close to the intersection between joint plane and surface plane, so that the pivoting takes place about a pivoting centre close to this point. Moreover, the locking system can be snapped together by horizontal displacement, essentially the 15 lower part of the tongue groove being bent and the locking element of the tongue snapping into the locking groove. Alternatively or furthermore, the tongue can be made flexible to facilitate such snapping-in at the short side after the long sides of the floorboards have been ;2 0 joined. Thus, the invention also relates to a snap joint which can be released by upward angling with upper joint edges in contact with each other. ;According to a third aspect of the invention, the floorboard has two edge portions with a joint system 25 which is formed according to the invention, where the tongue, while the board is held in an upwardly angled position, can be snapped into the tongue groove and then be angled down by a pivoting motion about the upper joint edge. In the upwardly angled position, the tongue can be ;3 0 partially inserted into the tongue groove by the board in this position being moved in a translatory movement to the tongue groove until the upper joint edges have come into contact with each other, after which downward angling takes place for final joining of tongue and 35 tongue groove and for obtaining a locking-together. The lower lip can be shorter than the upper lip so as to ;WO 02/055810 ;PCT/SE02/00043 ;32 ;enable greater degrees of freedom when designing the undercut of the upper lip. ;A plurality of aspects of the invention are also applicable to the known systems without these aspects 5 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 joint which is to be angled inwards with upper joint edges in 10 contact with each other and which is to be snapped in with a minimum bending of joint components. The invention also describes how material properties can be used to achieve great strength and low cost in combination with angling and snapping as well as laying methods. 15 Different aspects of the invention will now be described in more detail with reference to the accompanying drawings which show different embodiments of the invention. The parts of the inventive board that are equivalent to those of the prior-art board in Figs 1-2 20 have throughout been given the same reference numerals. ;Brief Description of the Drawings Figs la-c show in three steps a downward angling method for mechanical joining of long sides of floorboards according to WO 9426999. 25 Figs 2a-c show in three steps a snapping-in method for mechanical joining of short sides of floorboards according to WO 9426999. ;Figs 3a-b show a floorboard according to WO 9426999 ;seen from above and from below respectively. 30 Figs 4a-b show two different embodiments of floorboards according to WO 9966151. ;Figs 5a-b show floorboards according to DE-A-3343601. Figs 6a-d show mechanical locking systems for the long side and the short side respectively 35 of floorboards according to CA-A-0991373. ;Figs 7a-b show a mechanical locking system according to GB-A-1430429. ;WO 02/055810 ;PCT/SE02/00043 ;33 ;Figs 8a-b show boards according to DE-A-4242530. ;Figs 9a-b show a snap joint according to WO 9627721. ;Figs lOa-b show a snap joint according to JP 3169967. ;Figs lla-b show a snap joint according to DE-A-1212275. ;5 Figs 12a-d show different embodiments of locking systems based on tongue and groove according to US-A-1124228. ;Figs 13a-d show a mechanical joint system for sport floors according to DE-A-3041781. ;10 Figs 14a-e show one of the locking systems as shown in ;WO 9747834. ;Figs 15a-b show a parquet floor according to US-A-2740167. ;Figs 16a-b show a mechanical locking system for floor-15 boards according CA-A-2252791. ;Figs 17a-b show a snap-lock system for parquet floors according to US-A-5797237. ;Figs 18a-b show a joint system for ceramic tiles according to FR-A-2675174. ;2 0 Figs 19a-b show a joint system for floorboards which are described in JP 7180333 and are made by extrusion of metal material. ;Figs 20a-b show a joint system for large wall panels according to GB-A-2117813. ;25 Figs 21a-b show schematically to parallel joint edge portions of a first preferred embodiment of a floorboard according to the present invention. ;Fig. 22 shows schematically the basic principles of ;30 inward angling about upper joint edges when using the present invention. ;Figs 23a-b show schematically the production of a joint edge of a floorboard according to the invention. ;35 Figs 24a-b show a production-specific variant of the invention. ;WO 02/055810 ;PCT/SE02/00043 ;34 ;Pig. 25 shows a variant of the invention as well as snapping-in and upward angling in combination with bending of the lower lip. ;Fig. 2 6 shows a variant of the invention with a short ;5 lip. ;Figs 27a-c show a downward and upward angling method. ;Figs 28a-c show an alternative angling method. ;Figs 29a-b show a snapping-in method. ;Fig. 3 0 shows how the long sides of two boards are ;10 joined with the long side of a third board when the two boards are already joined with each other on the short sides. ;Figs 31a-b show two joined floorboards provided with a combination joint according to the invention. 15 Figs 32a-d show inward angling of the combination joint. ;Fig. 33 shows an example of how a long side can be formed in a parquet floor. ;Fig. 34 shows an example of how a short side can be formed in a parquet floor. ;20 Fig. 35 shows a detailed example of how the joint system of the long side can be formed in a parquet floor. ;Fig. 3 6 shows an example of a floorboard according to the invention where the joint system is 25 designed so that it can be angled by using bending and compression in the joint material. ;Fig. 37 shows a floorboard according to the inven tion. ;30 Figs 38a-b show a manufacturing method in four steps which uses a manufacturing method according to the invention. ;Fig. 39 shows a joint system which is suitable to compensate for swelling and shrinking of the 35 surfaee layer of the floorboard. ;Fig. 40 shows a variant of the invention with a rigid tongue. ;WO 02/055810 ;PCT/SE02/00043 ;35 ;Fig. 41 shows a variant of the invention where the locking surfaces constitute upper contact surfaces. ;Figs 42a-b show a variant of the invention with a long 5 tongue as well as angling and pulling out. ;Figs 43a-c show how the joint system should be designed to facilitate snapping in. ;Fig. 44 shows snapping-in in the angled position. ;Figs 45a-b show a joint system according to the inven-10 tion with a flexible tongue. ;Figs 46a-b show a joint system according to the invention with a split and flexible tongue. ;Figs 47a-b show a joint system according to the invention with a lower lip consisting partly of 15 another material than the core. ;Figs 48a-b show a joint system which can be used as snap joint in a floorboard that is locked on all four sides. ;Fig. 49 shows a joint system that can be used, for ;20 instance, on the short side of a floorboard. ;Fig. 50 shows another example of joint system which can be used, for instance, on the short side of a floorboard. ;Figs 51a-f show a laying method. ;25 Figs 52a-b show laying by means of a specially designed tool. ;Fig. 53 shows joining of short sides. ;Figs 54a-b show snapping-in of the short side. ;Fig. 55 shows a variant of the invention with a ;3 0 flexible tongue that facilitates snapping-in on the short side. ;Figs 56a-e show snapping-in of the outer corner portion of the short side. ;Figs 57a-e show snapping-in of the inner corner portion 35 of the short side. ;WO 02/055810 PCT/SE02/00043 ;36 ;Detailed Description of Preferred Embodiments ;A first preferred embodiment of a floorboard 1, 1', which is provided with a mechanical locking system according to the invention, will now be described with 5 reference to Figs 21a and 21b. To facilitate the understanding, the joint system is shown schematically. It should be emphasised that a better function can be achieved with other preferred embodiments that will be described below. ;10 Figs 21a, 21b show schematically a section through a joint between a long side edge portion 4a of a board 1 and an opposite long side edge portion 4b of another board 1'. ;The upper sides of the boards are essentially posi-15 tioned in a common surface plane HP and the upper parts of the joint edge portions 4a, 4b engage each other in a vertical joint plane VP. The mechanical locking system results in locking of the boards relative to each other in both the vertical direction D1 and the horizontal 20 direction D2 which extends perpendicular to the joint plane VP. During the laying of a floor with juxtaposed rows of boards, one board (1'), however, can be displaced along the other board (1) in a direction D3 (see Fig. 3a) along the joint plane VP. Such a displacement can be 25 used, for instance, to provide locking-together of floorboards that are positioned in the same row. ;To provide joining of the two joint edge portions perpendicular to the vertical plane VP and parallel with the horizontal plane HP, the edges of the floorboard have 30 in a manner known per se a tongue groove 36 in one edge portion 4a of the floorboard inside the joint plane VP, and a tongue 3 8 formed in the other joint edge portion 4b and projecting beyond the joint plane VP. ;In this embodiment the board 1 has a core or core 30 35 of wood which supports a surface layer of wood 32 on its front side and a balancing layer 34 on its rear side. The board 1 is rectangular and has a second mechanical lock ;WO 02/055810 ;PCT/SE02/00043 ;37 ;ing system also on the two parallel short sides. In some embodiments, this second locking system can have the same design as the locking system of the long sides, but the locking system on the short sides can also be of a diffe-5 rent design according to the invention or be a previously known mechanical locking system. ;As an illustrative, non-limiting example, the floorboard can be of parquet type with a thickness of 15 mm, a length of 2.4 m and a width of 0.2 m. The invention, 10 however, can also be used for parquet squares or boards of a different size. ;The core 3 0 can be of lamella type and consist of narrow wooden blocks of an inexpensive kind of wood. The surface layer 32 may have a thickness of 3-4 mm and con-15 sist of a decorative kind of hardwood and be varnished. The balancing layer 34 of the rear side may consist of a 2 mm 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 ;2 0 individual parts of the floorboard. ;As mentioned above, the mechanical locking system according to the invention comprises a tongue groove 36 in one joint edge portion 4a of the floorboard, and a tongue 3 8 on the opposite joint edge portion 4b of the 25 floorboard. ;The tongue groove 36 is defined by upper and lower lips 39, 40 and has the form of an undercut groove with an opening between the two lips 39, 40. ;The different parts of the tongue groove 36 are best 30 seen in Fig. 21b. The tongue groove is formed in the core or core 3 0 and extends from the edge of the floorboard. Above the tongue groove, there is an upper edge portion or joint edge surface 41 which extends up to the surface plane HP. Inside the opening of the tongue groove, there ;3 5 is an upper engaging or supporting surface 43 which in this case is parallel with the surface plane HP. This engaging or supporting surface passes into an inclined ;WO 02/055810 PCT/SE02/00043 ;38 ;locking surface 43 which has a locking angle A to the horizontal plane HP. Inside the locking surface, there is surface portion 4 6 which forms the upper boundary surface of the undercut portion 35 of the tongue groove. The 5 tongue groove further has a bottom end 48 which extends down to the lower lip 40. On the upper side of this lip there is an engaging or supporting surface 50. The outer end of the lower lip has a joint edge surface 52 and extends in this case slightly beyond the joint plane VP. 10 The shape of the tongue is also best seen in ;Fig. 21b. The tongue is made of the material of the core or core 3 0 and extends beyond the joint plane VP when this joint edge portion 4b is mechanically joined with the joint edge portion 4a of an adjoining floorboard. The 15 joint edge portion 4b also has an upper edge portion or upper joint edge surface 61 which extends along the joint plane VP down to the root of the tongue 38. The upper side of the root of the tongue has an upper engaging or supporting surface 64 which in this case extends to an 2 0 inclined locking surface 65 of an upwardly directed portion 8 close to the tip of the tongue. The locking surface 65 passes into a guiding surface portion 66 which ends in an upper surface 67 of the upwardly directed portion 8 of the tongue. After the surface 67 follows 25 a bevel which may serve as a guiding surface 68. This extends to the tip 69 of the tongue. At the lower end of the tip 69 there is a further guiding surface 7 0 which extends obliquely downwards to the lower edge of the tongue and an engaging or supporting surface 71. The 30 supporting surface 71 is intended to coact with the supporting surface 50 of the lower lip when two such floorboards are mechanically joined, so that their upper sides are positioned in the same surface plane HP and meet at a. joint plane VP directed perpendicular thereto, so that 35 the upper joint edge surface 41, 61 of the boards engage each other. The tongue has a lower joint edge surface 72 which extends to the underside. ;WO 02/055810 ;PCT/SE02/00043 ;39 ;In this embodiment there are separate engaging or supporting surface 43, 64 in the tongue groove and on the tongue, respectively, which in the locked state engage each other and coact with the lower supporting surfaces 5 50, 71 on the lower lip and on the tongue, respectively, to provide the locking in the direction D1 perpendicular to the surface plane HP. In other embodiments, which will . be described below, use is made of the locking surfaces 45, 65 both as locking surfaces for locking together in 10 the direction D2 parallel with the surface plane HP and as supporting surfaces for counteracting movements in the direction D2 perpendicular to the surface plane. In the embodiment according to Figs 21a, 2b, the locking surfaces 45, 65 and the engaging surfaces 43, 64 coact as 15 upper supporting surfaces in the system. ;As is apparent from the drawing, the tongue 3 8 extends beyond the joint plane VP and has an upwardly directed portion 8 at its free outer end or tip 69. The tongue has also a locking surface 65 which is formed to ;2 0 coact with the inner locking surface 45 in the tongue groove 36 of an adjoining floorboard when two such floorboards are mechanically joined, so that their front sides are positioned in the same surface plane HP and meet at a joint plane VP directed perpendicular thereto. 25 As is evident from Fig. 21b, the tongue 38 has a surface portion 52 between the locking surface 51 and the joint plane VP. When two floorboards are joined, the surface portion 52 engages the surface portion 4 5 of the upper lip 8. To facilitate insertion of the tongue into ;3 0 the undercut groove by inward angling or snapping-in, the tongue can, as shown in Figs 21a, 21b, have a bevel 66 between the locking surface 65 and the surface portion 57. Moreover, a bevel 68 can be positioned between the surface portion 57 and the tip 69 of the tongue. The 3 5 bevel 66 may serve as a guiding part by having a lower angle of inclination to the surface plane than the angle of inclination A of the locking surfaces 43, 51. ;WO 02/055810 ;PCT/SE02/00043 ;40 ;The supporting surface 71 of the tongue is in this embodiment essentially parallel with the surface plane HP. The tongue has a bevel 70 between this supporting surface and the tip 69 of the tongue. ;5 According to the invention, the lower lip 40 has a supporting surface 50 for coaction with the corresponding supporting surface 71 on the tongue 36 at a distance from the bottom end 4 8 of the undercut groove. When two floorboards are joined with each other, there is engagement 10 both between the supporting surfaces 50, 71 and between the engaging or supporting surface 43 of the upper lip 3 9 and the corresponding engaging or supporting surface 64 of the tongue. In this way, locking of the boards in the direction D1 perpendicular to the surface plane HP is 15 obtained. ;According to the invention, at least the major part of the bottom end 48 of the undercut groove, seen parallel with the surface plane HP, is located further away from the joint plane VP than is the outer end or tip 69 20 of the tongue 36. By this design, manufacture is simplified to a considerable extent, and displacement of one floorboard relative to another along the joint plane is facilitated. ;Another important feature of a mechanical locking 25 system according to the invention is that all parts of the portions of the lower lip 40 which are connected with the core 30, seen from the point C, where the surface plane HP and the joint plane VP intersect, are located outside a plane LP2, This plane is located further away 30 from said point C than a locking plane LP1 which is parallel with the plane LP2 and which is tangent to the coacting locking surfaces 45, 65 of the undercut groove 3 6 and the tongue 38, where these locking surfaces are most inclined relative to the surface plane HP. Owing to 35 this design, the undercut groove can, as will be described in more detail below, be made by using large disk- ;WO 02/055810 ;PCT/SE02/00043 ;41 ;shaped rotating cutting tools for machining of the edge portions of the floorboards. ;A further important feature of a locking system according to the present invention is that the upper 5 and lower lips 39, 4 0 and tongue 38 of the joint edge portions 4a, 4b are designed to enable disconnection of two mechanically joined floorboards by one floorboard being pivoted upwards relative to the other about a pivoting centre close to the point of intersection C 10 between the surface plane HP and the joint plane VP, so that the tongue of this floorboard is pivoted out of the undercut groove of the other floorboard. ;In the embodiment according to Figs 21a, 21b, such disconnection is made possible by a slight downward bend-15 ing of the lower lip 40. In other more preferred embodiments of the invention, no downward bending of the lower lip, however, is required in conjunction with connection and disconnection of the floorboards. ;In the embodiment according to Figs 21a, 21b, the 20 joining of two floorboards according to the invention can be carried out in three different ways. ;One way involves that the board 1' is placed on the base and moved towards the previously laid board 1' until the narrow tip 69 of the tongue 3 8 has been inserted into 25 the opening of the undercut groove 36. Then the floorboard 1' is angled upwards so that the upper parts 41, 61 of the boards on both sides of the joint plane VP contact each other. While maintaining this contact, the board is angled downwards by pivoting about the centre of 30 pivoting C. The insertion takes place by the bevel 66 of the tongue sliding along the locking surface 45 of the upper lip 3 9 while at the same time the bevel 7 0 of the tongue 3 8 slides against the outer edge of the upper side of the lower lip 40. The locking system can then be open-35 ed by the floorboard 1' being angled upwards by pivoting about the centre of pivoting C close to the intersection between the surface plane HP and the joint plane VP. ;WO 02/055810 ;PCT/SE02/00043 ;42 ;The second way of locking-together is provided by moving the new board with its joint edge portion 4a formed with a tongue groove towards the joint edge portion 4b, provided with a tongue, of the previously laid 5 board. Then the new board is pivoted upwards until contact is obtained between the upper parts 41, 61 of the boards close to the intersection between surface plane and joint plane, after which the board is pivoted downwards to bring tongue and groove together until the final 10 locked position is achieved. According to the following description, the floorboards can also be joined by one board being moved in an upwardly angled position towards the other. ;A third way of providing joining of the floorboards 15 in this embodiment of floorboards according to the invention involves that the new board 1' is displaced horizontally towards the previously laid board 1, so that the tongue 38 with its locking element or upwardly directed portion 8 is inserted into the tongue groove 36, the 20 lower flexible lip 40 being bent slightly downwards for the locking element 8 to snap into the undercut portion 35 of the tongue groove. Also in this case, disconnection takes place by upward angling as described above. ;In connection with snapping-in, also a small degree 25 of upward bending of the upper lip 3 9 can take place as can also a certain degree of compression of all the parts in the groove 36 and the tongue 38 which during snapping-in are in contact with each other. This facilitates snapping-in and can be used to form an optimal joint 3 0 system. ;To facilitate manufacture, inward angling, upward angling, snapping-in and displaceability in the locked position and to minimise the risk of creaking, all surfaces that are not operative to form a joint with tight 35 upper joint edges and to form the vertical and horizontal joint so as not to be in contact with each other in the locked position and preferably also during locking and ;WO 02/055810 ;PCT/SE02/00043 ;43 ;unlocking. This allows manufacture without requiring high tolerances in these joint portions and reduces the friction in lateral displacement along the joint edge. Examples of surfaces or parts of the joint system that should 5 not be in contact with each other in the locked position are 46-67, 48-69, 50-70 and 52-72. ;The joint system according to the preferred embodiment may consist of several combinations of materials. The upper lip 3 9 can be made of a rigid and hard upper 10 surface layer 32 and a softer lower part which is part of the core 30. The lower lip 40 can consist of the same softer upper part 3 0 and also a lower soft part 34 which can be another kind of wood. The directions of the fibres in the three kinds of wood may vary. This can be used to 15 provide a joint system which utilises these material properties. The locking element is therefore according to the invention positioned closer to the upper hard and rigid part, which thus is flexible and compressible to a limited extent-only, while the snap function is formed in 20 the softer lower and flexible part. It should be pointed that the joint system can also be made in a homogeneous floorboard. ;Fig. 22 shows schematically the basic principles of inward angling about a point C (upper joint edges) when 25 using the present invention. Fig. 22 shows schematically how a locking system should be designed to enable inward angling about the upper joint edges. In this inward angling, the parts of the joint system follow in prior-art manner a circular arc with is centre C close to the 3 0 intersection between the surface plane HP and the joint plane VP. If a great play between all parts of the joint system is allowed, or if essential deformation during inward angling is possible, the tongue and groove can be formed in many different ways. If, on the other hand, the 35 joint system must have contact surfaces that prevent vertical and horizontal separation without any play between the engaging or supporting surfaces and if ;WO 02/055810 ;PCT/SE02/00043 ;44 ;material deformation is not possible, the joint system should be constructed according to the following principles. ;The upper part of the joint system is formed as fol-5 lows. C1B is a circular arc which has it centre C at the top at the upper joint edges 41, 61 and which in this preferred embodiment intersects a contact point between the upper lip 39 and the upper part of the tongue 38 at the point P2. All the other contact points between P2, 10 P3, P4 and P5 between the upper lip 39 and the upper part 8 of the tongue 38 and between this point of intersection P2 and the vertical plane VP are positioned on or inside this circular arc C1B, whereas all other contact points from P2 to PI between the upper lip 39 and the upper part 15 of the tongue 3 8 and between this point of intersection P2 and the outer part of the tongue 3 8 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, the case is that 20 all other contact points between PI and P5 are positioned outside the circular arc CIA, and regarding the contact point PI, all other contact points between PI and P5 are positioned inside the circular arc C1C. ;The lower part of the joint system is formed accord-25 ing to the corresponding principles. C2B is a circular arc which is concentric with the circular arc CIA and which in this preferred embodiment intersects a contact point between the lower lip 40 and the lower part of the tongue 38 at the point P7. All the other contact points 3 0 between P7, P8 and P9 between the lower lip 4 0 and the lower part of the tongue 38 and between this point of intersection 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 4 0 and 35 the lower part of the tongue 3 8 and between this point of intersection P7 and the outer part of the tongue 38 are positioned on or inside this circular arc C2B. The same ;WO 02/055810 ;PCT/SE02/00043 ;45 ;applies to the contact point P6 with the circular arc C2A. ;A joint system constructed according to this preferred embodiment may have good inward angling properties. ;5 It can easily be combined with upper engaging or supporting surfaces 43, 64 which can be parallel with the horizontal plane HP and which can thus provide excellent vertical locking. ;Pigs 23a, 23b show how a joint system according to 10 Figs 21a, 2b can be produced. Normally, the floorboard ;1 according to prior art is positioned with its surface ;2 downwards on a ball bearing chain in a milling machine which conveys the board with extremely great accuracy past a number of milling cutters which, for instance, ;15 have a tool diameter of 80-300 mm and which can be set at an optional angle to the horizontal plane of the board. To facilitate the understanding and the comparison with the other drawings figures, the floorboard, however, is shown with its surface plane HP directed upwards. 20 Fig. 23a shows how the first tool with the tool position TP1 makes a traditional tongue groove. The tool operates in this case at a tool angle TA1 which is 0°, i.e. parallel with the horizontal plane. The axis of rotation RA1 is perpendicular to HP. The undercut is made by means of 25 a second tool, where the position TP2 and the design of the tool are such that the undercut 3 5 can be formed without the tool affecting the shape of the lower lip 40. In this case, the tool has an angle TA2 which is equal to the angle of the locking surface 45 in the undercut 35. 3 0 This manufacturing method is possible by the locking plane LPl being located at such a distance from the joint plane that the tool can be inserted into the previously formed tongue groove. The thickness of the tool therefore cannot exceed the distance between the two planes LPl and 35 LP2, as discussed in connection with Figs 21a and 21b. ;This manufacturing method is prior-art technique and does ;WO 02/055810 PCT/SE02/00043 ;46 ;not constitute part of the manufacturing method according to the present invention as will be described below. ;Figs 24a, 24b show another variant of the invention. This embodiment is characterised in that the joint system 5 is formed completely according to the basic principle of inward angling about the upper joint edges as described above. The locking surfaces 45, 65 and the lower supporting surfaces 50, 71 are in this embodiment plane, but they can have a different shape. CI and C2 are two circu-10 lar arcs with their centre C at the upper end of adjoining joint edges 41, 61. The smaller circular arc CI is tangent to the lower contact point closest to the vertical plane between the locking surfaces 45, 65 at the point P4 which has the tangent TL1 corresponding to the 15 locking plane LPl. The locking surfaces 45, 65 have the same inclination as this tangent. The greater circular arc 62 is tangent to the upper contact point between the lower supporting surfaces 50, 71 closest to the inner part 4 8 of the tongue groove at the point P7, which has 20 the tangent TL2. The supporting surfaces 50, 71 have the same inclination as this tangent. ;All the contact points between the tongue 3 8 and the upper lip 39 which are positioned between the point P4 and the vertical plane VP satisfy the condition that they 25 are positioned inside or on the circular arc CI, 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 - satisfy the condition that they are positioned on or outside CI. The 3 0 corresponding conditions are satisfied for the contact surfaces between the lower lip 40 and the tongue 38. All contact points between the tongue 3 8 and the lower lip 40 which are positioned between the point P7 and the vertical plane VP - in this case only the lower supporting 35 surfaces 50, 71 - are positioned on or outside the circular arc C2, while all contact points which are positioned between the point P7 and the inner part 4 8 of the tongue ;WO 02/055810 ;PCT/SE02/00043 ;47 ;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 embodiment is characterised in particular in 5 that all contact surfaces between the contact point P4 and the joint plane VP, in this case the point P5, and the inner part 4 8 of the tongue groove, respectively, are positioned inside and outside, respectively, the circular arc CI and thus not on the circular arc CI. The same 10 applies to the 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, respectively, are positioned outside and inside, respectively, the circular arc C2 and thus not on the circular 15 arc C2. As is evident from the part indicated by broken lines in Fig. 24a, the joint system can, if this condition is satisfied, be designed so that inward angling can take place with clearance during essentially the entire angular motion which can be terminated by the boards 2 0 being locked with a tight fit or with a press fit when they have taken their final horizontal position. Thus, the invention enables a combination of an inward angling and upward angling without resistance and a locking with high joint quality. If the lower supporting surfaces 71, ;2 5 50 are made with a somewhat lower angle, a joint 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 angling ;3 0 until final locking takes place, and during the entire upward angling until the boards can be released from each other. Locking with clearance or with only line contact is a great advantage since the friction will be low and the boards can easily be angled inward and angled upward 3 5 without parts of the system getting stuck and pinching each other with a risk of the joint system being damaged. A press fit especially in the vertical direction is very ;WO 02/055810 PCT/SE02/00043 ;48 ;important for the strength. If there is play between the engaging or supporting surfaces, the boards will, when subjected to tensile load, slide along the locking surfaces until the lower engaging or supporting surfaces 5 have taken a position with a press fit. Thus a play will result in both a joint gap and differences in level between upper joint edges. As an example, it may be mentioned that with a tight fit or press fit, high strength can be achieved if the locking surfaces have an angle of 10 about 40° to the surface plane HP and if the lower engaging or supporting surfaces have an angle of about 15° to the surface plane HP. ;The locking plane LPl has in Fig. 24a a locking angle A to the horizontal plane HP of about 3 9°, while 15 the supporting plane TL2 along the supporting surfaces 50, 71 has a supporting angle VLA of about 14°. The difference in angle between LPl and the supporting plane TL2 is 25°. A high locking angle and a great difference in angle between locking angle and supporting angle should ;2 0 be strived for since this results in a great horizontal locking force. The locking surfaces and the supporting surfaces can be made arcuate, stepped, with several angles etc, but this makes manufacture difficult. As mentioned above, the locking surfaces may also constitute 25 upper supporting surfaces or be complements to separate upper supporting surfaces. ;Even if the locking surfaces and supporting surfaces have contact points that deviate somewhat from these basic principles, they can be angled inward at ;3 0 their upper joint edges if the joint system is adjust ed so that its contact points or surfaces are small in relation to the floor thickness and so that the properties of the board material in the form of compression, elongation and bending are used maximally in combination 35 with very small plays between the contact surfaces. ;This can be used to increase the locking angle and the ;WO 02/055810 ;PCT/SE02/00043 ;49 ;difference in angle between locking angle and supporting angle. ;The basic principle of inward angling thus shows that the critical parts are the locking surfaces 45, 65 5 and the lower supporting surfaces 50, 71. It also shows that the degree of freedom is great as regards designing of the other parts, for instance the upper supporting surfaces 43, 64, the guiding 44 of the locking groove, the guiding 66 and the top surface 67 of the locking 10 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, 72 of the tongue. These should preferably deviate from the shape of the two circular arcs CI and C2, and between 15 all parts except the upper supporting surfaces 43, 64 there can 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 facilitates manufacture significantly since these parts ;2 0 can be formed without great tolerance requirements, and it contributes to safe inward angling and upward angling and also lower friction in connection with lateral displacement of joined boards along the joint plane VP (direction D3) . By free spaces is meant joint parts that 25 do not have any functional meaning to prevent vertical or horizontal displacement and displacement along the joint edge in the locked position. Thus, loose wood fibres and small deformable contact points should be considered equivalent to free surfaces. ;3 0 Angling about the upper joint edge can, as mentioned above, be facilitated if the joint system is constructed so that there can be a small play between above all said locking surfaces 45, 65 if the joint edges of the boards are pressed together. The construction play also facili-35 tates lateral displacement in the locked position, ;reduces the risk of creaking and gives greater degrees of freedom in manufacture, allows inward angling with lock- ;WO 02/055810 ;PCT/SE02/00043 ;50 ;ing surfaces that have a greater inclination than the tangent LPl and contribute to compensating for swelling of upper joint edges. The play gives considerably smaller joint gaps at the upper side of the boards and consider-5 ably smaller vertical displacements than would a play between the engaging or supporting surfaces, above all owing to this play being small and also owing to the fact that a sliding in the tensile-loaded position will follow the angle of the lower supporting surface, i.e. an angle 10 which is essentially smaller than the locking angle. This minimal play, if any, between the locking surfaces can be very small, for instance only 0.01 mm. In the normal joined position the play can be non-existent, i.e. 0, the joint system can be constructed so that a play appears 15 only in maximal pressing together of the joint edges of the boards. It has been found that also a greater play of about 0.05 mm will result in a very high joint quality, since the joint gap which is to be found in the surface plane HP and which may arise in the tensile-loaded posi-20 tion is hardly visible. ;It should be pointed out that the joint system can be constructed without any play between the locking surfaces . ;Play and material compression between the locking 25 surfaces and bending of joint parts at the locking surfaces can easily be measured indirectly by the joint system being subjected to tensile load and the joint gap at the upper joint edges 41, 61 being measured at a predetermined load which is less than the strength of the 30 joint system. By strength is meant that the joint system is not broken or does not snap out. A suitable tensile load is about 50% of the strength. As a non-limiting standard value, it may be mentioned that a long side joint should normally have a strength exceeding 300 kg 35 per running meter of joint. Short side joints should have still greater strength. A parquet floor with a suitable joint system according to the invention can withstand a ;WO 02/055810 PCT/SE02/00043 ;51 ;tensile load of 1000 kg per running meter of joint. A high-quality joint system should have a joint gap at the upper joint edges 41, 61 of about 0.1-0.2 mm when subjected to tensile load with approximately half the maxi-5 mum strength. The joint gap should decrease when the load ceases. By varying the tensile load, the relationship between construction play and material deformation can be determined. In case of lower tensile load, the joint gap is essentially a measure of the construction play. In 10 case of a higher load, the joint gap increases owing to material deformation. The joint system can also be constructed with built-in initial stress and a press fit between locking surfaces and supporting surfaces, so that the above-mentioned joint gap is not visible in case of 15 the above-mentioned load. ;The geometry of the joint system, play between the locking surfaces in combination with compression of the material round the upper joint edges 41, 61 can also be measured by the joint being sawn up transversely of the ;2 0 joint edge. Since the joint system is manufactured with linear machining, it will have the same profile along its entire joint edge. The only exception is manufacturing tolerances in the form of lack of parallelism owing to the fact that the board can optionally be turned or dis-25 placed vertically or horizontally as it passes different milling tools in the machine. Normally seen, the two samples from each joint edge, however, give a very reliable picture of what the joint system looks like. After grinding the samples and cleaning them of loose ;3 0 fibres so that a sharp joint profile is to be seen, ;they can be analysed as regards joint geometry, material compression, bending etc. The two joint parts can, for instance, be compressed by means of a force which is such as not to damage the joint system, above all the upper 35 joint edges 41, 61. The play between the locking surfaces and the joint geometry can then be measured in a measuring microscope with an accuracy of 0.01 mm or less ;WO 02/055810 PCT/SE02/00043 ;52 ;according to equipment. If stable and modern machines are used in manufacture, it is as a rule sufficient to measure the profile in two smaller areas of a floorboard to determine the average play, joint geometry etc. ;5 All measuring should take place when the floorboards are conditioned at a normal relative humidity of about 45%. ;Also in this case, the locking element or the upwardly directed portion 8 of the tongue has a guiding 10 part 66. The guiding part of the locking element comprises parts having an inclination which is lower than the inclination of the locking surface and, in this case, also the inclination of the tangent TL1. A suitable degree of inclination of the tool that produces the lock-15 ing surface 45 is indicated by TA2 which in this embodiment is equal to the tangent TL1. ;Also the locking surface 45 of the tongue groove has a guiding part 44 which coacts with the guiding part 66 of the tongue during inward angling. Also this guiding 20 part 44 comprises parts that have a smaller inclination than the locking surface. ;In the front part of the lower lip 40, there is a rounded guiding part 51, which coacts with the radius in the lower part of the tongue in connection with the lower 25 engaging surface 71 at the point P7 and which facilitates inward angling. ;The lower lip 40 can be resilient. In connection with inward angling, a small degree of compression can also take place of the contact points between the lower 30 parts of the tongue 38 and the lower lip 40. As a rule, ;this compression is significantly smaller than may be the case for the locking surfaces since the lower lip 40 can have considerably better resilience properties than the upper lip 3 9 and the tongue 38, respectively. In connec-35 tion with inward angling and upward angling, the lip can thus be bent downwards. A bending capacity of merely one tenth of a millimetre or somewhat more gives, together ;WO 02/055810 PCT/SE02/00043 ;53 ;with material compression and small contact surfaces, ;good chances of forming, for instance, the lower supporting surfaces 50, 71, so that they can have an inclination which is smaller than the tangent TL2 while at the 5 same time inward angling can easily be made. A flexible lip should be combined with a relatively high locking angle. If the locking angle is low, a large amount of the tensile load will press the lip downward, which results in undesirable joint gaps and differences in level 10 between the joint edges. ;Both the tongue groove 36 and the tongue 38 have guiding parts 42, 51 and 68, 70 which guide the tongue into the groove and facilitate snapping-in and inward angling. ;15 Fig. 25 illustrates variants of the invention, where the lower lip 40 is shorter than the upper lip 3 9 and thus is positioned at a distance from the vertical plane VP. The advantage is that there will be greater degrees of freedom in designing the locking groove 45 20 with a high tool angle TA while at the same time relatively large tools can be used. To facilitate snapping-in by downward bending of the lower lip 40, the tongue groove 36 has been made deeper than is required by the space for the tip of the tongue 38. The dash-dotted joint 25 edge portion 4b shows how the parts of the system are related to each other in connection with inward angling about the upper joint edge, while the dashed joint edge portion 4b shows how the parts of the system are related to each other in connection with snapping-in of the 3 0 tongue into the tongue groove by displacement of the joint edge portion 4b straight towards the joint edge portion 4a. ;Fig. 2 6 shows a further variant of the above-mentioned basic principles. The joint system is here 35 formed with locking surfaces which are angled at 90° ;to the surface plane HP and which are considerably more angled than the tangent TL1. Such a preferred locking ;WO 02/055810 ;PCT/SE02/00043 ;54 ;system, however, is openable by upward angling by the locking surfaces being extremely small and by the joint locking essentially only by line contact. If the core is hard, such a locking system can give high strength. The 5 design of the locking element and the locking surfaces allows snapping-in with only a small degree of downward bending of the lower lip, as indicated by means of dashed lines. ;Figs 2 7a-c show a laying method by inward angling. 10 To facilitate the description, one board is referred to as groove board and the other as tongue board. In practice, the boards are identical. A possible laying method involves that the tongue board lies flat on the subfloor either as a loose board or joined with other boards on 15 one, two or three sides, depending on where in the laying sequence/row it is positioned. The groove board is placed with its upper lip 39 partly over the outer part of the tongue 38, so that the upper joint edges are in contact with each other. Then the groove board is turned down 20 towards the subfloor while being pressed against the joint edge of the tongue board until final locking takes place according to Fig. 27c. ;The sides of floorboards sometimes have a certain degree of bending. The groove board is then pressed 25. and turned downwards until parts of the upper lip 39 are in contact with parts of the upwardly directed portion or locking element 8 of the tongue and parts of the lower lip 4 0 are in contact with parts of the lower part of the tongue. In this manner, any bending of the sides can 3 0 be straightened, and then the boards can be angled to their final position and locked. ;Figs 27a-c show that the inward angling can take place with clearance, or alternatively merely contact between the upper part of the tongue groove and the 35 tongue or with line contact between the upper and lower parts of the tongue and the tongue groove. Line contact can in this embodiment arise at points P4 and P7. Inward ;WO 02/055810 ;PCT/SE02/00043 ;- 55 ;angling can easily take place without considerable resistance and can be terminated with a very close fit that locks the floorboards in the final position with high joint quality vertically and horizontally. ;5 Summing up, the downward angling can in practice be carried out as follows. The groove board is moved at an angle towards the tongue board, the tongue groove being passed over part of the tongue. The groove board is pressed towards the tongue board and angled gradually 10 downwards using, for instance, compression in the centre of the board and, after that, on both edges. When the upper joint edges over the entire board are close to each other or in contact with each other, and the board has taken a certain angle to the subfloor, the final downward 15 angling can be made. ;When the boards have been joined, they can be displaced in the locked position in the joint direction, i.e. parallel with the joint edge. ;Figs 2 8a-c show how a corresponding laying can be 2 0 carried out by the tongue board being angled into groove board. ;Figs 29a-b show joining by snapping-in. When the boards are moved towards each other horizontally, the tongue is guided into the groove. During continued com-25 pression, the lower lip 40 bends, and the locking element 8 snaps into the locking groove or the undercut 35. It should be emphasised that the preferred joint system shows the basic principles of snapping-in, where the lower lip is flexible. The joint system must, of course, 30 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 4 0 and should be dimensioned so that snapping-in is feasible. The basic principles of a joint system according 35 to the invention which is more convenient for use in materials with a lower degree of flexibility and bend- ;WO 02/055810 ;PCT/SE02/00043 ;56 ;ability will be evident from the following description and Fig. 34. ;The described laying methods can be used optionally on all four sides and be combined with each other. After 5 laying of one side, a lateral displacement usually takes place in the locked position. ;In some cases, for instance in connection with inward angling of the short side as a first operation, an upward angling of two boards usually takes place. 10 Fig. 3 0 shows a first board 1, and an upwardly angled second board 2a and an upwardly angled new third board 2b which on its short side is already joined with the second board 2b. After the new board 2b has been laterally displaced along the short side of the second board 2a in the 15 upwardly angled and short-side-locked position, the two boards 2a and 2b can be angled down jointly and locked on the long side to the first board 1. For this method to function, it is required that the new board 2b can be inserted with its tongue into the tongue groove when the 20 board is displaced parallel with the second board 2a and when the second board 2a has a part of its tongue partially inserted into the tongue groove and when its upper joint edge is in contact with the upper joint edge of the first board 1. Fig. 30 shows that the joint system can be 25 made with such a design of the tongue groove, tongue and locking element 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 boards are 3 0 joined on their short sides, after which a whole row is laid simultaneously. This is, however, not a rational laying method. ;Figs 31a, 31b show part of a floorboard with a combination joint. The tongue groove 3 6 and the tongue 38 35 can be formed according to one of the embodiments above. The groove board has on its underside a known strip 6 with a locking element 8b and a locking surface 10. The ;WO 02/055810 ;PCT/SE02/00043 ;57 ;tongue side has a locking groove 35 according to a known embodiment. In this embodiment, the locking element 8b with its relatively large guiding part 9 will function as an extra guiding during the first part of the inward 5 angling and significantly facilitates this first part of the inward angling when positioning takes place and any banana shape is straightened out. The locking element 8b causes automatic positioning and compression of the floorboards until the guiding part of the tongue is 10 engaged with the locking groove 35 and final locking can take place. The laying is facilitated to a considerable extent, and the joint will be very strong by coaction of the two locking systems. This joint is very convenient for joining of large floor surfaces particularly in 15 public rooms. In the shown example, the strip 6 has been attached to the groove side, but it can also be attached to the tongue side. The positioning of the strip 6 thus is optional. Moreover, the joint can be both snapped in and angled upwards and be laterally displaced in the 20 locked position. ;Of course, this joint can be used optionally in different variants on both long and short side, and it can be optionally'combined with all joint variants described here and with other known systems. ;25 A convenient combination is a snap system on the short side without an aluminium strip. This may in some cases facilitate manufacture. A strip that is attached after manufacture also has the advantage that it may also constitute part of or even the entire lower lip 40. This 30 gives very great degrees of freedom for forming, with cutting tools, for instance the upper lip 39 and forming locking surfaces with high locking angles. The locking system according to this embodiment can, of course, be made snappable, and it can also be manufactured with an 35 optional width of the strip, for instance with a strip 6 that does not protrude outside the outer part of the upper lip 39, as is the case in the embodiment according ;WO 02/055810 PCT/SE02/00043 ;58 ;to Fig. 50. The strip need not be continuous over the entire length of the joint but may consist of several small portions which are attached with space in between on both long side and short side. ;5 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 facilitate inward angling or snapping-in. ;10 Figs 32a-d illustrate in four steps how inward angling can be made. The broad strip 6 makes it possible for the tongue 3 8 to be easily laid on the strip at the beginning of the inward angling. The tongue can then, in connection with downward angling, essentially automati-15 cally slide into the tongue groove 36. The corresponding laying can be made by the strip 6 being inserted under the tongue board. All laying functions that have been described above can also be used in floorboards with this preferred combination system. ;20 Figs 33 and 34 show a production-specific and opti mised joint system for above all a floorboard with a core of wood. Fig. 33 shows how the long side can be formed. In this case, the joint system is optimised with regard to, above all, inward angling, upward angling and a small 25 amount of material waste. Fig. 34 shows how the short side can be formed. In this case, the joint system is optimised for snapping-in and high strength. The differences are as follows. The tongue 3 8 and the locking element of the short side 5a are longer, measured in the 3 0 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 be bent downwards to a greater extent. The locking element 8 is on the short side 5a lower in the vertical direction, 35 which reduces the requirement for the downward bending of the lower lip in connection with the snapping. The locking surfaces 45, 65 have a higher locking angle and the ;WO 02/055810 ;PCT/SE02/00043 ;59 ;lower engaging surfaces have a lower angle. The guiding parts of the long side 4a, 4b in the locking element and the locking groove are greater for optimal guiding, while at the same time the contact surface between the locking 5 surfaces is smaller since the strength requirements are lower than for the short side. The joint systems on the long and short side can consist of different materials or material properties in upper lip, lower lip and tongue, and these properties can be adjusted so that they contri-10 bute to optimising the different properties that are desired for long side and short side, respectively, with regard to function and strength. ;Fig. 3 5 shows in detail how the joint system of the floorboard can be formed on the long side. The prin-15 ciples here described can, of course, be used on both long side and short side. Only the parts that have previously not been discussed in detail will now essentially be described. ;The locking surfaces 45, 65 have an angle HLA which 20 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 optimised with regard to compression and flexural rigidity so that inward angling and upward angling can still take 25 place. The contact surfaces of the locking surfaces should be minimised and adjusted to the properties of the core. ;When the boards are joined, a small part, preferably less than half the extent of the locking element in the 3 0 vertical direction, constitutes the contact surfaces of the locking element 8 and the locking groove 14. The major part constitutes rounded, inclined or bent guiding parts which in the joined position and during inward angling and upward angling are not in contact with each 35 other. ;The inventor has discovered that very small contact surfaces in relation to the floor thickness T between the ;WO 02/055810 ;PCT/SE02/00043 ;60 ;locking surfaces 45, 65 of, for instance, a few tenths of a millimetre 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 (i.e. the 5 surface plane HP). This can be used to provide locking surfaces with an angle exceeding the tangent TL1. ;In this case, the locking surfaces 45, 65 are plane and parallel. This is advantageous especially as regards the locking surface 55 of the locking groove. If the tool 10 is displaced parallel with the locking surface 45, this will not affect the vertical distance to the joint plane VP, and it is easier to provide a high joint quality. Of course, small deviations from the plane form may give equivalent results. ;15 Correspondingly, the lower supporting surfaces 50, ;71 have been made essentially plane and with an angle VLA2 which in this case is greater than the tangent line TL2 to the point P7 which is positioned on the supporting surface 71 closest to the bottom of the tongue groove. 2 0 This causes inward angling with clearance during essentially the entire angular motion. Also the supporting surfaces 50, 71 are relatively small in relation to the floor thickness T. These supporting surfaces can also be made essentially plane. Plane supporting surfaces facili-25 tate the manufacture according to the above described principles. ;The supporting surfaces 50, 71 can also be made with angles that are smaller than the angle of inclination of the tangent TL2. In this case, angling can take place 30 partly 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 that are greater and smaller, 35 respectively, than the tangent TL1 and TL2, respectively, increase. ;WO 02/055810 ;PCT/SE02/00043 ;Fig. 3 6 shows upward angling of a board which has a geometry according to Fig. 35 and whose locking surfaces thus have a greater inclination than the tangent TL1 and whose supporting surfaces have a smaller inclination than 5 the tangent TL2 while at the same time these surfaces are relatively small. The overlap at the 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 the material being com-10 pressed at the upper joint 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 direction B1 and B2 from the contact point P4. The lower lip can bend downwards away from the contact point P7 in the direction B3. 15 The upper supporting surfaces 43, 64 are preferably perpendicular to the joint plane VP. The manufacture is facilitated significantly if the upper and lower supporting surfaces are plane-parallel and preferably horizontal . ;20 Reference is once more made to Fig. 35. The circular arc CI shows, for instance, that the upper supporting surfaces can be formed in many different ways inside this circular arc CI without this interfering with the possibilities of angling and snapping. In the same way, the 25 circular arc C2 shows that the inner parts of the tongue groove and the outer parts of the tongue according to the previously preferred principles can be formed in many, different ways without this interfering with the possibilities of angling and snapping. ;30 The upper lip 39 is over its entire extent thicker than the lower lip 40. This is advantageous from the viewpoint of strength. Moreover, this is advantageous in connection with parquet floors, which as a result can be formed with a thicker surface layer of a hard kind of 35 wood. ;S1-S5 indicate areas where joint surfaces on both sides should not be in contact with each other at least ;WO 02/055810 ;PCT/SE02/00043 ;62 ;in the joined 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 improving the locking in D1 direction and hardly at 5 all to improving the locking in the D2 direction. However, a contact prevents inwardly angling and lateral displacement, causes unnecessary tolerance problems in connection with manufacture and increases the risk of creaking and undesired effects as the boards swell. 10 The tool angle TA, which in Fig. 38d is indicated by ;TA4, forms the locking surface 44 of the undercut 35 and operates with the same angle as the angle of the locking surface, and the part of this tool which is positioned inside the vertical plane towards the tongue groove has 15 a width perpendicular to the tool angle TA which is indicated by TT. The angle TA and the width TT determine partly the possibilities of forming the outer parts 52 of the lower lip 40. ;A plurality of ratios and angles are important for 20 an optimal manufacturing method, function, cost and strength. ;The extent of the contact surfaces should be minimised. This reduces friction and facilitates displacement in the locked position, inward angling and snapping in, -25 simplifies manufacture and reduces the risk of swelling problems and creaking. In the preferred example, less than 30% of the surface parts of the tongue 38 constitute contact surfaces with the tongue groove 36. The contact surfaces of the locking surfaces 65, 45 are in this embo-3 0 diment only 2% of the floor thickness T, and the lower supporting surfaces have a contact surface which is only 10% of the floor thickness T. As mentioned above, the locking system has in this embodiment a plurality of parts S1-S5 which constitute free surfaces without con-35 tact with each other. The space between these free surfaces and the rest of the joint system can within the scope of the invention be filled with glue, sealing ;WO 02/055810 ;PCT/SE02/00043 ;63 ;agent, impregnation of different kinds, lubricant and the like. By free surfaces is here meant the form of the surfaces in the joint system that it obtains in connection with machining by means of the respective cutting 5 tools. ;If the joint has a tight fit, the locking surfaces 65, 45 can prevent horizontal separation even when they have an angle HLA to the horizontal plane HP which is greater than zero. The tensile strength of the joint 10 system, however, increases significantly when this locking angle becomes greater and when there is a difference in angle between the locking angle HLA of the locking surfaces 45, 65 and the engaging angle VLA2 of the lower supporting surfaces 50, 71, provided that this angle is 15 smaller. If high strength is not required, the locking surfaces can be formed with low angles and small differences in angle to the lower engaging surfaces. ;For good joint quality in floating floors, the locking angle HLA and the difference in angle to lower sup- ;2 0 porting surfaces HLA - VLA2 must as a rule be about 2 0°. ;Still better strength is obtained if the locking angle HLA and the difference in angle HLA-VLA2 is, for instance 3 0°. In the preferred example according to Fig. 35, the locking angle is 5 0° and the angle of the supporting sur-25 faces 20°. As shown in previous embodiments, joint systems according to the invention can be formed with still greater locking angles and differences in angle. ;A large number of tests have been made with different locking angles and engaging' angles. These tests ;3 0 prove that it is possible to form a high-quality joint system with locking angles between 4 0° and 55° and with supporting surface angles between 0° and 25°. It should be emphasised that also other ratios can result in a satisfactory function. ;35 The horizontal extent PA of the tongue should exceed ;1/3 of the thickness T of the floorboard, and it should preferably be about 0.5 * T. As a rule, this is necessary WO 02/055810 PCT/SE02/00043 64 for a strong locking element 8 with a guiding 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. 5 The horizontal extent PA of the tongue 38 should be divided into two essentially equal parts PA1 and PA2, where PA1 should constitute the locking element and the major part of PA2 should constitute the supporting surface 64. The horizontal extent PA1 of the locking element 10 should not be less than 0.2 times the floor thickness. The upper supporting surface 64 should not be too great, above all on the long side of the floorboard. Otherwise, the friction in connection with lateral displacement can be too high. To enable rational manufacture, the depth 15 G of the tongue groove should be 2% deeper than the projection of the tongue PA from the joint plane VP. The smallest distance of the upper lip to the floor surface adjacent to the locking groove 3 5 should be greater than the smallest distance of the lower lip between the lower 2 0 supporting surface 71 and the rear side of the floor board. The tool width TT should exceed 0.1 times the floor thickness T. Figs 37a-c illustrate a floorboard according to the invention. This embodiment shows specifically that the 25 joint system on the short side may consist of different materials and material combinations 30b and 3 0c and that these can also differ from the joint material 30 of the long side. For instance, the tongue groove part 36 of the short sides may consist of a harder and more flexible 3 0 wood material than, for instance, the tongue part 38 which can be hard and rigid and have other properties than the core of the long side. On the short side with the tongue groove 36, it is possible to select, for instance, a kind of wood 3 0b which is more flexible than 35 the kind of wood 30c on the other short side where the tongue is formed. This is particularly convenient in parquet floors with a lamellar core where the upper and WO 02/055810 PCT/SE02/00043 65 lower side consist of different kinds of wood and the core consists of blocks that have been glued together. This construction gives great possibilities of varying the composition of materials in order to optimise func-5 tion, strength and production costs. It is also possible to vary the material along the length of one side. Thus, for instance the blocks that are positioned between the two short sides can be of different kinds of wood or materials, so that some of 10 them can be selected with regard to their contributing with suitable properties which improve laying, strength etc. Different properties can also be obtained with different fibre orientation on long and short side, and also plastic materials can be used on the short sides and, for 15 instance, on different parts of the long side. If the floorboard or parts of its core consist of, for example, plywood with several layers, these layers can be selected so that the upper lip, the tongue and the lower lip on both long side and short side can all have parts with a 20 different composition of materials, fibre orientation etc. which can give different properties as regards strength, flexibility, machinability etc. Figs 3 8a-d show a manufacturing method according to the present invention. In the shown embodiment, the manu-25 facture of the joint edge and the tongue groove occurs in four steps. The tools used have a tool diameter which exceeds the floor thickness. The tools are used to form an undercut groove with a high locking angle in a tongue groove with a lower lip, which extends beyond the under-3 0 cut groove. In order to simplify the understanding and the comparison with previously described joint systems, the edges of the boards are illustrated with the floor surface directed upwards. Normally, the boards are, however, 35 positioned with their surface directed downwards during machining. WO 02/055810 PCT/SE02/00043 66 The first tool TP1 is a roughing cutter which operates at an angle TA1 to the horizontal plane. The second tool TP2 can operate horizontally and forms the upper and lower supporting surfaces. The third tool TA3 can operate 5 essentially vertically but also at an angle and forms the upper joint edge. The critical tool is the tool TP4 which forms the outer part of the locking groove and its locking surface. TA4 corresponds to TA in Fig. 35. As is evident from 10 Fig. 38d, this tool removes only a minimum amount of the material and forms essentially the locking surface with a high angle. For the tool not to break, it should be formed with a wide part which is extended outside the vertical plane. Moreover, the amount of material to be 15 removed should be as small as possible to reduce wear and strain on the tool. This is achieved with a suitable angle and design of the roughing cutter TP1. Thus this manufacturing method is characterised especially in that it requires at least two cutting tools 20 which operate at two different angles to form an undercut locking groove 35 in the upper part of the tongue groove 36. The tongue groove can be made using still more tools, the tools being used in a different order. The description is now aimed in detail at the method 25 of forming a tongue groove 3 6 in a floorboard, which has an upper side 2 in a surface plane HP and a joint edge portion 4a having a joint plane VP directed perpendicular to the upper side. The tongue groove extends from the joint plane 4a and is defined by two lips 39, 40 each 30 having a free outer end. In at least one lip, the tongue groove has an undercut 3 5 which comprises a locking surface 4 5 and is positioned further away from the joint plane VP than is the free outer end 52 of the other lip. According to the method, machining is carried out by 35 means of a plurality of rotating cutting tools which have a larger diameter than the thickness T of the floorboard. In the method, the cutting tools and the floorboard are WO 02/055810 PCT/SE02/00043 made to perform a relative motion relative to each other and parallel to the joint edge of the floorboard. What characterises the method is 1) that the undercut is formed by means of at least two such cutting tools, which 5 have their rotatary shaft inclined at different angles to the upper side 2 of the floorboard; 2) that a first of these tools is driven to form portions of the undercut further away from the joint plane VP than the locking surface 45 of the intended undercut; and 3) that a second 10 of these tools is driven to form the locking surface 45 of the undercut. The first of these tools is driven with its rotary shaft set at a greater angle to the upper side 2 of the floorboard than is said second of these tools. The lower lip 40 can be formed so as to extend beyond the 15 joint plane VP. The lower lip 40 can also be formed so as to extend to the joint plane VP. Alternatively, the lower lip 4 0 can be formed so as to end at a distance from the joint plane VP. The first of the tools can, according to an embodi-2 0 ment, be driven with its rotary shaft set at an angle of at most 85° to the surface plane HP. The second of the tools can, according to an embodiment, be driven with its rotary shaft set at an angle of at most 60° to the surface plane HP. Moreover the tools can be caused to 25 engage the floorboard in order in dependence on the angle of their rotary shaft to the surface plane HP, so that tools with a greater angle of the rotary shaft are caused to machine the floorboard before tools with a smaller angle of the rotary shaft. 30 Moreover, a third of the tools can be driven to form the lower parts of the tongue groove 36. This third tool can be brought into contact with the floorboard between said first and said second of the tools. The third tool can further be driven with its rotary shaft set at an 35 angle of about 90° to the surface plane HP. Further the first of the tools can be driven to machine a broader surface portion of the joint edge por WO 02/055810 PCT/SE02/00043 68 tion 4a of the floorboard than said second of the tools. The second of the tools can be formed so that its surface facing the surface plane HP is profiled for reduction of the thickness of the tool, seen parallel with the 5 rotary shaft, within the radially outer portions of the tool. Moreover, at least three of the tools can be driven with different settings of their rotary shaft to form the undercut parts of the tongue groove. The tools can be used to machine a floorboard of wood or wood-fibre-based 10 material. Fig. 39 shows how a joint system can be formed to enable compensation for swelling. Since the relative humidity increases in the change between cold and warm weather, the surface layer 32 swells and the floorboards 15 4a and 4b are pressed apart. If the joint has no flexibility, the joint edges 41 and 61 can be crushed, or the locking element 8 can be broken. This problem can be solved by the joint system being constructed so as to obtain the following properties which each separately and 2 0 in combination contribute to a reduction of the problem. The joint system can be formed so that the floorboards can have a small play when the joint edges are pressed together horizontally, for instance, in connection with production and at normal relative humidity. A 25 play of a few hundredths of a millimetre contributes to a reduction of the problem. A negative play, i.e. initial stress, can give the opposite effect. If the contact surface between the locking surfaces 45, 65 is small, the joint system can be formed so that 3 0 the locking surfaces are more easily compressed than the upper joint edges 41, 61. The locking element 8 can be formed with a grove 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, 35 the outer part 69 of the tongue can be bent outwards to the inner part 48 of the tongue groove and operate as a WO 02/055810 PCT/SE02/00043 69 resilient element in connection with swelling and shrinking of the surface layers. In this embodiment, the lower supporting surfaces of the joint system are formed parallel with the horizontal 5 plane for maximum locking vertically. It is also possible to obtain expansibility by applying a compressible material between, for instance, the two locking surfaces 45, 65 or selecting compressible materials as materials for the tongue or groove part. 10 Fig. 40 shows a joint system according to the inven tion which has been optimised for high rigidity 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 15 without very great compression, the joint system can be displaceable in the locked position. Fig. 41 shows a joint system where the lower supporting surfaces 50, 71 have two angles. The portions of the supporting surfaces outside the joint plane are 20 parallel with the horizontal plane. Inside the joint plane closest to the inner part of the tongue groove, they have an angle corresponding to the tangent to the circular arc 3 2 which is tangent to the innermost edge of the supporting surface parts engaging each other. The 25 locking surfaces have a relatively low 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 great to the parallel part of the lower supporting surfaces 50, 71. In this embodiment, the locking sur-30 faces 45, 65 also serve as upper supporting surfaces. The joint system has no upper supporting surfaces in addition to the locking surfaces which thus also prevent vertical separation. Figs 42a and 42b show a joint system which is con-35 venient for short side locking and which can have high tensile strength also in softer materials since the locking element 8 has a large horizontal shear-absorbing sur- WO 02/055810 PCT/SE02/00043 70 face. The tongue 38 has a lower part which is positioned outside the circular arc C2 and which thus does not follow the above-described basic principle of inward angling. As is apparent from Fig. 42b, the joint system can 5 still be released by upward angling about the upper joint edges since the locking element 8 of the tongue 38, after the first upward angling operation has been carried out, can leave the tongue groove by being pulled out horizontally. The previously described principles for inward 10 angling and upward angling about upper joint edges should thus be satisfied to enable upward angling until the joint system can be released in some other manner by, for instance, being pulled out or in combination with snapping out when the lower lip 40 is being bent. 15 Figs 43a-c show the basic principle of how the lower part of the tongue is to be formed in relation to the lower lip 40 to facilitate horizontal snapping-in according to the invention in a joint system with locking grooves in a rigid upper lip 3 9 and with a flexible lower 20 lip 40. In this embodiment, the upper lip 39 is significantly more rigid, inter alia owing to the fact that it may be thicker or that it may consist of harder and more rigid materials. The lower lip 40 can be thinner and softer, and in connection with snapping-in the essential 25 bending will therefore take place in the lower lip 40. Snapping-in can be significantly facilitated, among other things, by the maximal bending of the lower lip 4 0 being limited as far as possible. Fig. 43a shows that the bending of the lower lip 4 0 will increase to a maximal bend-3 0 ing level 331 which is characterised by the tongue 38 being inserted so far into the tongue groove 3 6 that the rounded guiding parts will come into contact with each other. When the tongue 3 8 is inserted still more, the lower lip 49 will be bent backwards until snapping-in is 35 terminated and the locking element 8 is fully inserted in its final position in the locking groove 35. The lower and front part 49 of the tongue 3 8 should be designed so WO 02/055810 PCT/SE02/00043 71 as not to bend down the lower lip 4 0 which instead should be forced downwards by the lower supporting surface 50. This part 49 of the tongue should have a shape which either touches or goes clear of the maximum bending level 5 of the lower lip 40 when this lower lip 40 is bent round 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 4 9b, the bending B2 according to Fig. 43b can 10 be significantly greater. This may cause great friction in connection with snapping-in and a risk of the joint being damaged. Fig. 43c shows that the maximum bending can be limited by the tongue groove 36 and the tongue 38 being designed in such manner that there is a space S4 15 between the lower and outer part 4 9 of the tongue and the lower lip 40. Horizontal snapping-in is as a rule used in connection with snapping-in of the short side after locking of the long side. When snapping in the long side, it is also 2 0 possible to snap the joint system according to the inven tion with one board in a slightly upwardly angled position. This upwardly angled snap position is shown in Fig. 44. Only a small bending B3 of the lower lip 40 is required for the guiding part 66 of the locking element 25 to come into contact with the guiding part 44 of the locking groove, so that the locking element can then by downward angling be inserted into the locking groove 35. Figs 45-50 show different variants of the invention which can be used on the long or short side and which can 3 0 be manufactured using large rotating cutting tools. With modern manufacturing technology it is possible to form according to the invention complicated shapes by machining in board materials at a low cost. It should be pointed out that most of the shown geometries in these and 35 previously preferred figures can, of course, be formed, for example, by extrusion, but this method is usually considerably more expensive than machining and is not WO 02/055810 PCT/SE02/00043 72 convenient for forming of most board materials that are normally used in floors. Figs 4 5a and 4 5b show a locking system according to the invention where the outer part of the tongue 3 8 has 5 been formed so as to be bendable. This bendability has been obtained by the tip of the tongue being split. During snapping-in, the lower lip 4 0 bends downwards and the outer lower part of the tongue 38 bends upwards. Figs 46a and 4 6b show a locking system according to 10 the invention with a split tongue. During snapping-in, the two parts of the tongue bend towards each other while at the same time the two lips bend away from each other. These two joint systems are such as to allow angling inwards and outwards, respectively, for locking and dis-15 mounting. Figs 4 7a and 47b show a combination joint where a separate part 40b constitutes an extended part of the lower lip and where this part can be resilient. The joint system is angleable. The lower lip, which constitutes 20 part of the core, is formed with its supporting surface in such a manner that snapping-in can take place without this lip needing to be bent. Merely the extended separate part, which can be made of aluminium sheet, is resilient. The joint system can also be formed so that both parts of 25 the lip are resilient. Figs 48a and 48b show snapping-in of a combination joint with a lower lip consisting of two parts, where merely the separate lip constitutes the supporting surface. This joint system can be used, for instance, on the 30 short side together with some other joint system according to the invention. The advantage of this joint system is that, for instance, the locking groove 35 can be formed with great degrees of freedom rationally and using large cutting tools. After the machining, the outer lip 35 40b is attached, and its shape does not affect the possibilities of machining. The outer lip 4 0b is resilient and has in this embodiment no locking element. Another advan WO 02/055810 PCT/SE02/00043 73 tage is that the joint system enables joining of extremely thin core materials since the lower lip can be made very thin. The core material can be, for instance, a thin compact laminate, and the upper and the lower layer can 5 be relatively thick layers of e.g. cork or soft plastic material, which can give a soft and sound-absorbing floor. Using this technology, it is possible to join core materials having a thickness of about 2 mm compared with normal core materials which as a rule are not thinner 10 than 7 mm. The saving in thickness that can be achieved can be used to increase the thickness of the other layers. It is obvious that'this joint can be used also in thicker materials. Figs 49 and 50 show two variants of combination 15 joints which can be used, for example, in the short side in combination with other preferred systems. The combination joint according to Fig. 49 can be made in an embodiment where the strip constitutes an extended resilient part of the tongue, and the system will then have a func-20 tion similar to the one in Fig. 45. Fig. 50 shows that this combination joint can be formed with a locking element 8b in the outer lower lip 40b which is positioned inside the joint plane. Figs. 51a-f show a laying method which is according 25 to the invention and which can be used to join floorboards by a combination of horizontal bringing-together, upward angling, snapping in the upwardly angled position and downward angling. This laying method can be used for floorboards according to the invention, but it can also 3 0 be used on optional mechanical joint systems in floors having such properties that the laying method can be applied. To simplify the description, the laying method is shown by one board, referred to as the groove board, being joined with the other board, referred to as the 35 tongue board. The boards are in practice identical. It is obvious that the entire laying sequence can also be car WO 02/055810 PCT/SE02/00043 74 ried out by the tongue side being joined with the groove side in the same way. A tongue board 4a with a tongue 38 and a groove board 4b with a tongue groove 3 6 are in the starting 5 position lying flat on a subfloor according to Fig. 51a. The tongue 38 and the tongue groove 36 have locking means which present vertical and horizontal separation. Subsequently the groove board 4b is displaced horizontally in the direction F1 towards the tongue board 4a until 10 the tongue 3 8 is in contact with the tongue groove 36 and until the upper and lower parts of the tongue are partially inserted into the tongue groove according to Fig. 51b. This first operation forces the joint edge portions of the boards to take the same relative verti-15 cal position over the entire longitudinal extent of the board, and any differences in arcuate shape will therefore be straightened out. If the groove board is moved towards the tongue board, the joint edge portion of the groove board will be 2 0 slightly raised in this position. The groove board 4b is then angled upwards with an angular motion SI while at the same time it is held in contact with the tongue board or alternatively is pressed in the direction F1 towards the tongue board 4a according to Fig. 51c. When the 25 groove board 4b reaches an angle SA to the subfloor which corresponds to an upwardly angled snap position, according to the above description and as shown in Fig. 44, the groove board 4b can be moved towards the tongue board 4a so that the upper joint edges 41, 61 come into contact 30 with each other and so that the locking means of the tongue are partially inserted into the locking means of the tongue groove by a snap function. This snap function in the upwardly angled position is characterised in that the outer parts of the tongue 35 groove widen and spring back. The widening is essentially smaller than is required in connection with snapping in in the horizontal position. The snap angle SA is depen WO 02/055810 PCT/SE02/00043 75 dent on the force by which the boards are pressed towards each other in connection with upward angling of the groove board 4b. If the press force in the direction F1 is high, the boards will snap in at a lower angle SA than 5 if the force is low. The snapping-in position is also characterised in that the guiding parts of the locking means are in contact with each other so that they can perform their snapping-in function. If the boards are banana-shaped, they will be straightened out and locked 10 in connection with the snapping-in. The groove board 4b can now, with an angular motion S2 combined with pressing towards the joint edge, be angled downwards according to Fig. 51e and locked against the tongue board in its final position. This is illustrated in Fig. 51f. 15 Depending on the construction of the joint, it is possible to determine with great accuracy the snap angle SA which gives the best function with regard to the requirement that the snapping-in should take place with a reasonable amount of force and that the guiding parts of 20 the locking means should be in such engagement that they can hold together any banana shape, so that a final locking can take place without any risk of the joint system being damaged. The floorboards can according to the preferred lay-25 ing method be installed without any actual aids. In some cases, the installation can be facilitated if it is carried out with suitable aids according to Figs 52a and 52b. A preferred aid according to the present invention can be a striking or pressing block 8 0 which is designed 3 0 so as to have a front and lower part 81 which angles the groove board upwards when it is inserted under the edge portion of the floorboard. It has an upper abutment edge 82 which in the upwardly angled position is in contact with the edge portion of the groove board. When the 35 striking block 80 has been inserted under the groove board so that the abutment edge 82 is in contact with the floorboard, the groove board will have the predetermined WO 02/055810 PCT/SE02/00043 76 snap angle. The tongue groove of the groove board 4a can now be snapped together with the tongue of the tongue board by pressing or striking against the striking block. Of course, the striking block can be moved to different 5 parts of the board. It is obvious that this can take place in combination with other pressing against the other parts of the board, using a plurality of striking blocks and using different types of aids which give a similar result where, for instance, one aid angles the 10 board up to the snapping-in angle and another is used for pressing together. The same method can be used if instead one wants to angle up the groove side of the new board and join it with the tongue side of the previously laid board. 15 The description will now be aimed at different aspects of a tool for laying of floorboards. Such a tool for laying of floorboards by interconnecting a tongue and groove joint thereof can be designed as a block 80 with an engaging surface 82 for engaging a joint edge 4a, 4b 20 of the joint edge portion of the floorboard. The tool can be formed as a wedge for insertion under the floorboard and have its engaging surface 82 arranged close to the thick end of the wedge. The engaging surface 82 of the tool can be concavely curved for at least partial enclo-25 sure of the joint edge 4a, 4b of the floorboard. Moreover the wedge angle SI of the wedge and the position of the engaging surface 82 on the thick portion of the wedge can be adjusted to obtain a predetermined lifting angle of a floorboard when it is being lifted with the wedge 80 and 3 0 the joint edge of the floorboard contacts the engaging surface 82. The abutment surface 82 of the wedge 80 can be formed to abut against a joint edge portion 4b which has a tongue 3 8 directed obliquely upwards for joining an undercut tongue groove 36 formed at the opposite joint 35 edge portion 4a of the floorboard with the tongue 38 of a previously laid floorboard. Alternatively, the abutment surface 82 of the wedge can be formed to abut against a WO 02/055810 PCT/SE02/00043 77 joint edge portion 4a, which has an undercut groove 36, for joining a tongue 38 directed obliquely upwards and formed at the opposite joint edge portion 4b of the floorboard. 5 The tool described above can be used for mechanical joining of floorboards by lifting one floorboard relative to another and joining and locking of mechanical locking systems of the floorboards. The tool can also be used for mechanical joining of such a floorboard with 10 another such floorboard by snapping together the mechanical locking systems of the floorboards while the floorboard is in its lifted state. Furthermore the tool can be used so that the engaging surface 82 of the wedge is made to abut against a joint edge portion 4b which has 15 a tongue 38 directed obliquely upwards for joining an undercut groove 36 formed at the opposite joint edge portion 4a of the floorboard with the tongue 3 8 of a previously laid floorboard. Alternatively the tool can be used so that the engaging surface 82 of the wedge is made 2 0 to abut against a joint edge portion 4a which has an undercut groove 36, for joining a tongue 3 8 which is directed obliquely upwards and formed at the opposite joint edge portion 4b of the floorboard with the undercut groove 3 8 of a previously laid floorboard. 25 Fig. 53 shows that the boards 2a and 2b, after being joined with adjoining boards along the long side edge, can be displaced in the locked position in the direction F2 so that joining of the other two sides can take place by a horizontal snapping together. 3 0 Snapping-in in the upwardly angled position can take place of long sides as well as short sides. If the short side of one board has first been joined, its long side can also be snapped in the upwardly angled position by this board with its locked short being angled up so that 3 5 it takes its snap angle. Subsequently, snapping-in takes place in the upwardly angled position while at the same time displacement in the locked position takes place WO 02/055810 PCT/SE02/00043 78 along the short side. After snapping-in, the board is angled down and it is locked on both long side and short side. Moreover, Figs 53 and 54 describe a problem which 5 can arise in connection with snapping-in of two short sides of two boards 2a and 2b which have already been joined on their long sides with another first board 1. When the floorboard 2a is to snap into the floorboard 2b, the inner corner portions 91 and 92, closest to the long 10 side of the first board 1, are located in the same plane. This is due to the fact that the two boards 2a and 2b on their respective long sides are joined to the same floorboard 1. According to Fig. 54b, which shows the section C3-C4, the tongue 3 8 cannot be inserted into the tongue 15 groove 3 6 to begin the downward bending of the lower lip 40. In the outer corner portions 93, 94 on the other long side, in the section C1-C2 shown in Fig. 54a, the tongue 3 8 can be inserted into the groove 3 6 to begin the downward bending of the lower lip 40 by the board 2b being 2 0 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 snapping-in of inner corner portions in lateral displacement in the same plane and 25 that these problems may cause a high snapping-in resistance and a risk of cracking in the joint system. The problem can be solved by a suitable joint design and choice of materials which enable material deformation bending in a plurality of joint portions. 3 0 When snapping-in such a specially designed joint system, the following takes place. In lateral displacement, the outer guiding parts 42, 68 of the tongue and the upper lip coact and force the locking element 8 of the tongue under the outer part of the upper lip 39. The 35 tongue bends downward and the upper lip bends upward. This is indicated by arrows in Fig. 54b. The corner portion 92 in Fig. 53 is pressed upward by the lower lip WO 02/055810 PCT/SE02/00043 79 40 on the long side of the board 2b being bent and the corner portion 91 being pressed downward by the upper lip on the long side of the board 2a being bent upward. The joint system should be constructed so that the sum of 5 these four deformations is so great that the locking element can slide along the upper lip and snap into the locking groove. It is known that it should be possible for the tongue groove 36 to widen in connection with snapping-in. However, it is not known that it may be an 10 advantage if the tongue, which normally should be rigid, should also be designed so as to be able to bend in connection with snapping-in. Such an embodiment is shown in Fig. 55. A groove or the like 63 can be made at the upper and inner part of the tongue inside the vertical plane 15 VP. The entire extent PB of the tongue from its inner part to its outer part can be extended, and it can, for instance, be made greater than half the floor thickness T. Figs 56 and 57 show how the parts of the joint sys- 2 0 tem bend in connection with snapping-in at the inner corner portion 91, 92 (Fig. 57) and the outer corner portion 93, 94 (Fig. 56) of two floorboards 2a and 2b. To simplify manufacture, it is required that only the thin lip and the tongue bend. In practice, of course all parts 25 that are subjected to pressure will be compressed and bent to a varying degree depending on thickness, bendabi-lity, composition of materials etc. Figs 56a and 57a show the position when the edges of the boards come into contact with each other. The joint 3 0 system is constructed in such manner that even in this position, the outermost tip of the tongue 38 will be located inside the outer part of the lower lip 40. When the boards are moved further towards each other, the tongue 38 in the inner corner 91, 92 will press the board 35- 2b upward according to Figs 56b, 57b. The tongue will bend downward and the board 2b at the outer corner 93, 94 will be angled upward. Fig. 57c shows that the tongue 3 8 WO 02/055810 PCT/SE02/00043 80 at the inner corner 91, 92 will be bent downward. At the outer corner 93, 94 according to Fig. 56c, the tongue 38 is bent upward and the lower lip 40 is bent downward. According to Figs 56d, 57d, this bending continues when 5 the boards are moved further towards each other, and now also the lower lip 40 is bent at the inner corner 91, 92 according to Fig. 57d. Figs 56e, 57e show the snapped-in position. Snapping-in can thus be facilitated significantly if the tongue 38 is bendable and if the outer 10 part of the tongue 38 is positioned inside the outer part of the lower lip 40 when tongue and groove come into contact with each other as the boards are located in the same plane in connection with snapping-in that takes place after the floorboard has already been locked along 15 its two other sides. Several variants can exist within the scope of the invention. The inventor has manufactured and evaluated a large number of variants where the different parts of the joint system have been manufactured with different 20 widths, lengths, thicknesses, angles and radii of a number of different board materials and of homogeneous plastic and wooden panels. All joint systems have been tested in a position turned upside-down and with snapping and angling of groove and tongue boards relative to each 25 other and with different combinations of the systems here described and also prior-art systems on long side and short side. Locking systems have been manufactured where locking surfaces are also upper engaging surfaces, where the tongue and groove have had a plurality of locking 30 elements and locking grooves, and where also the lower lip and the lower part of the tongue have been formed with horizontal locking means in the form of locking element and locking groove. WO 02/055810 PCT/SE02/00043 81 </div>

Claims

<div class="application article clearfix printTableText" id="claims"> CLAIMS

1. A locking system for mechanical joining of_floor-5 boards at a joint plane; said floorboards ■ having a core, a front side; a rear side and opposite joint edge portions^ cf which one 'is formed as a tongue groove which is defined by upper and lower lips and has a bottom 10 end7 and the other is formed as a tongue with an upwardly directed portion ' at its free outer end, the' tongue groove., seen from the joint plane^ having "the shape of an undercut groove with an : 15 opening, an inner portion and an inner locking surface, . _ and at least parts of the lower lip being formed inte grally with the core of the floorboard/ and the tongue ' having a locking surface which is 20 formed to coact with the inner locking surface in the tongue groove of an adjoining floor board, when two such floorboards • are mecha nically joined, so that their front sides 'are positioned in the same surface plane and .25 meet at the joint plane directed perpendicular thereto, wherein at least the major part of the bottom end ■ of the tongue groove/ seen parallel with the surface 3 0 plane; . , is positioned further away from the joint plane than is the outer end ■of the tongue, and wherein the inner locking surface of the tongue groove is formed on the upper lip . within the 35 ' undercut portion of the tongue groove for coac tion with the corresponding locking surface _ of the tongue7 which locking surface is formed on IPONZ - 7 JUL 2004 WO 02/055810 PCT/SE02/00043 82 the upwardly directed portion of the tongue to counteract pulling apart of two mechanically joined boards in a direction perpendicular to the joint' plane, and wherein the lower lip has a supporting surface for coaction with a corresponding supporting surface on the tongue at a distance from the bot tom end 'of the undercut groove, said supporting surfaces being intended to coact to counteract a 10 relative displacement of two mechanically joined boards in a direction perpendicular to the sur face plane, and wherein all parts of the portions of the lower lip which are connected with the core, seen from the 15 point where the surface plane and the joint plane intersect, are located outside a plane which is located further away from said point than a locking plane .. which is parallel there with and which is tangent to the coacting locking 2 0 surfaces of the tongue groove and the tongue ' where said locking surfaces are most inclined relative to the surface plane?, and and wherein the upper and lower lips and tongue of the joint edge portions are designed 25 to enable disconnection of two mechanically joined floorboards by upward pivoting of one floorboard relative to the other about a pivoting centre close to a point of intersection between the surface plane and the joint plane for disconnec- 3 0 tion of the tongue of one floorboard and the tongue groove of the other floorboard*

2. A locking system as claimed in claim 1, characterised in that the upper and lower lips and tongue of the joint edge portions 3 5 are designed to enable joining of two floorboards by one floorboard, while the two floorboards are essentially in contact with each other, being pivoted IPONZ '7 JUL 2004 WO 02/055810 PCT/SE02/00043 83 downward relative to the other about a pivoting centre close to a point of intersection between the surface plane and the joint plane for joining the tongue of one floorboard with the tongue groove of the 5 other floorboard.

3. A locking system as claimed in claim 1 or 2, characterised in that the undercut groove and the tongue have such a design that a floorboard which is mechanically joined with a similar board 10 is displaceable in a direction along the joint plane.

4. A locking system as claimed in claim 1, 2 or 3, characterised in that the tongue and the undercut groove are designed to enable connection 15 and disconnection of one board with and from another board by pivoting one board relative to the other while maintaining contact between the boards at a point on the joint edge portions of the boards close to the intersection between the surface plane 'and the joint 20 plane,

5. A locking system as claimed in any one of the preceding claims, characterised in that the tongue and the undercut groove are designed to enable connection and disconnection of boards by 25 pivoting one board relative to another while maintaining contact between the boards at a point on the joint edge portions of the boards close to the intersection between the surface plane and the joint plane without essential contact between the side of the tongue 30 facing away from the surface plane and the lower lip.

6. A locking system as claimed in any one of claims 1-4, characterised in that the tongue and the undercut groove are designed to enable con- 35 nection and disconnection of boards -by pivoting one board relative to another while maintaining contact between the boards at a point on the joint edge portions IPONZ " 7 JUL 2004 WO 02/055810 PCT/SE02/00043 84 of the boards close to the intersection between the surface plane and the joint plane and in essentially line contact between the sides of the tongue facing the surface plane ' and facing away from the 5 surface plane and the upper and the lower lip' respectively.

7. A locking system as claimed in any one of the preceding claims, characterised in that the distance between the locking plane and the plane 10 parallel therewith, outside which all parts of the portions of the lower lip which are connected with . the core are located, is at least 10% of the thick ness of the floorboard.

8. A locking system as claimed in any one of the 15 preceding claims,. characterised in that the locking surfaces of the upper lip and the tongue form an angle to the surface plane ' of below 90° but at least 20°.

9. A locking system as claimed in claim 8, 20 characterised in that the locking surfaces of the upper lip and the tongue form an angle to the surface plane of at least 3 0°.

10. A locking system as claimed in any one of the preceding claims, characterised in that the 25 undercut groove and the tongue are designed so that the outer end of the tongue is located at a distance from the undercut groove along .essential ly the entire distance from the locking surfaces, engaging each other, of the upper lip , 'and the 3 0 tongue to the coacting supporting surfaces ." of the lower lip and the tongue.

11. A locking system as claimed in claim 10, characterised in that any surface portions with contact between the outer end of the tongue 35 - and the undercut groove have a smaller extent in the vertical plane than do the locking surfaces when two such, boards are mechanically joined. IPONZ -7 JUL m WO 02/055810 PCT/SE02/00043 85

12. A locking system as claimed in any one of the preceding claims, characterised in that the edge portions ■ with their tongue and tongue groove are designed so that when two floorboards are 5 joined there is surface contact between the edge portions along at most 3 0% of the edge surface of the edge portion supporting the tongue, measured from the upper'side of the floorboard to its underside,

13. A locking system as claimed in any one of the 10 preceding claims, characterised in that the coacting supporting surfaces of the tongue and the lower lip are parallel with the surface plane or directed at an angle thereto which is equal to or smaller than a tangent to a circular arc which is 15 tangent to the supporting surfaces engaging each other at a point closest to the bottom of the undercut groove and which has its centre at a point 'where the surface plane and the joint plane 'intersect, seen in cross-section through the board. 20 14. A locking system as claimed in claim 13, characterised in that the coacting supporting surface of the tongue and the lower lip are set an angle of 0° to 3 0° to the surface plane. 25 15. A locking system as claimed in claim 14, characterised in that the coacting supporting surfaces of the tongue and the lower lip are set at an angle of at least 10° to the surface plane. 3 0 16. A locking system as claimed in claim 14 or 15, characterised in that the coacting supporting surfaces of the tongue and the lower lip are set an angle of at most 2 0° to the surface plane. 35 17. A locking system as claimed in claim 13, characterised in that the coacting supporting surfaces of the tongue and the lower lip IPONZ - 7 JUL 2001 WO 02/055810 PCT/SE02/00043 86 are set at essentially the same angle to the surface plane as a tangent to a circular arc which is tan gent to the supporting surfaces ■ and has its centre at the point where the surface plane and the 5 joint plane 'intersect, seen in cross-section through the board.

18. A locking system as claimed in claim 13, characterised in that the coacting supporting surfaces of the tongue and the lower lip 10 are set at a greater angle to the surface plane than a tangent to a circular arc which is tangent to the supporting surfaces engaging each other at a point closest to the bottom of' the undercut groove and which has its centre at a point where the surface plane 15 and the joint plane intersect.

19. A locking system as claimed in any one of the preceding claims, characterised in that the supporting surfaces ■of the tongue and the lower lip, which are designed for coaction, are set - 2 0 at a smaller angle to the surface plane than are the coacting locking surfaces of the upper lip and the tongue,

20. A locking system as claimed in claim 19, characterised in that the supporting surfaces 2 5 of the tongue and the lower lip7 which are designed for coaction, are inclined in the same direction but at a smaller angle to the surface plane than are the coacting locking surfaces of the upper lip and the tongue. 30 21. A' locking system as claimed in any one of claims 13-20, characterised in that the supporting surfaces form an at least 2 0° greater angle to _ -the surface plane than do the locking surfaces, 35 22. A locking system as claimed in any one of the preceding claims^. characterised in that part of the locking surface of the upper lip IPONZ 7 JUL 2004 WO 02/055810 PCT/SE02/00043 87- is located closer to the bottom of the tongue groove than, is part of the supporting surfaces 23 . A locking system as claimed in any one of the preceding claims, characterised in that the 5 locking surfaces of the upper lip and the tongue are essentially plane within at least the surface portions which are intended to coact with each other when two such boards are j oined.

24. A locking system as claimed in claim 23, 10 characterised in that the tongue has a guiding surface which, is located outside the locking surface of the tongue, seen from the joint plane^ and which has a smaller angle to the surface plane than does this locking surface. 15 25. A locking system as claimed in any one of the "preceding claims, c h a r a c t e'r'i s e d in that the upper lip has a guiding surface which is locat ed closer to the opening of the tongue groove than is the locking surface of the upper lip and which 2-0 has a smaller angle to the surface plane than does the! locking surface of the upper lip.

26. A locking system as claimed in any one of the. preceding claims, characterised in that the lower lip extends to or preferably ends at a dis- 25 tance from the joint plane* - 2 7. A locking system as claimed in any one ox the preceding claims, characterised in that, the lower lip is shorter than the upper lip and ends at a distance from the joint plane? and that 3 0 at least parts of the supporting surfaces of the lower lip and the tongue are located at a greater distance from the joint plane than are the inclined locking surfaces of the upper lip and the tongue^ 35 2 8. A locking system as claimed in any one of the preceding claims, characterised in that locking surface of the tongue is arranged at IPONZ 7 JUL 2CD4 WO 02/055810 PCT/SE02/00043 88 a distance of at least 0.1 times the thickness of the floorboard from the tip ' of the tongue.

29. A locking system as claimed in any one of the 5 preceding claims, characterised in that the vertical extent of the coacting locking surfaces is smaller than half the vertical extent of the undercut seen from the joint plane and parallel with the surface plane. 10 30. A locking system as claimed in any one of the preceding claims, characterised in that the locking surfaces, seen in a vertical section through the floorboard, have an extent which is at most 10% of the thickness of the floorboard. 15 31. A locking system as claimed in any one of the preceding claims, characterised in that the length of the tongue, seen perpendicular away from the joint plane? is at least 0.3 times the thickness of the floorboard. 2 0 32. A locking system as claimed in any one of the preceding claims, characterised in that the -joint edge portion supporting the tongue and/or the joint edge portion supporting the tongue groove has/ have a recess which is positioned above the tongue 2 5 and ends at a distance from the surface plane, 33 . A locking system as claimed in any one of the preceding claims, characterised in that the upper lip and the tongue have contact surfaces which in their locked state coact with each 3 0 other and which are located within an area between the joint plane and the locking surfaces of the tongue and the upper lip, which in their locked state coact with each other.

34. A locking system as claimed in claim 33, 35 characterised in that the contact surfaces are essentially plane. IPONZ 7 JUL 2004 WO 02/055810 PCT/SE02/00043 89

35. A locking system as claimed in claim 33 or 34, characterised in that the contact surfaces are inclined upwards" to the surface plane in the direction towards the joint plane, 5 36. A locking system as claimed in claim 33 or 34, characterised in that the contact surfaces are essentially parallel with the surface plane,

37. A locking system as claimed in any one of the 10 preceding claims, characterised in that the lower lip of the tongue groove is flexible.

38. A locking system as claimed in any one of the preceding claims, characterised in that it is formed as a snap lock which is openable by upward angling 15 of one board relative to the other,-

39. A locking system, as claimed in any one of the preceding claims, characterised in that it is formed for joining a previously laid floorboard with a new floorboard by a pushing-together motion essentially 2 0 parallel with the surface plane of the previously laid floorboard for snapping together the parts of the locking system.

40. A locking system as claimed in any one of the preceding claims, characterised in that the 25 undercut groove, seen in cross-section, has an■outer opening portion that tapers inwards in the shape of a funnel.

41. A locking system as claimed in claim'40, characterised in that the upper lip has 3 0 a bevel at its outer edge furthest away from the surface plane,

42. A locking system as claimed in any one of the ^ ' preceding claims, characterised in that the tongue, seen in cross-section, has a tip that 3 5 tapers.

43. A locking system as claimed in any one of the preceding claims, .characterised in that the IPONZ - 7 JUL 2004 WO 02/055810 PCT/SE02/00043 90 tongue^ seen in cross-section, has a split tip with an upper and a lower . tongue part.

44. A locking system as claimed in "claim 43, characterised in that the upper and 5 lower tongue parts of the tongue are made of different materials having different material properties.

45. A locking system as claimed in any one of the preceding claims, characterised in that the tongue groove and tongue are formed integrally with 10 the floorboard.

46. A locking system as claimed in any one of the preceding claims, characterised in that the locking surfaces are set at a greater angle to surface plane than a 'tangent to a circular arc which 15 is tangent to the locking surfaces which engage each other at a point closest to the bottom of the undercut groove, and which has its centre at the point where the surface plane and the joint plane intersect. 20 47 . A locking system as claimed in any one of the preceding claims, characterised in that the upper lip is thicker than the lower lip.

48. A locking system as claimed in any one of the preceding claims, characterised in that the 25 minimum thickness of the upper lip adjacent to the undercut . is greater than the maximum thickness of the lower lip adjacent to the supporting surface.

49. A locking system as claimed in any one of the 3 0 preceding claims, characterised, in that the extent of the supporting surfaces is at most 15% of the thickness of the floorboard.

50. A locking system as claimed in any one of the preceding claims, characterised in that the 3 5 vertical extent of the tongue groove . between the upper- and the lower lip, measured parallel with the joint plane and at the outer end of the supportIPONZ 7 JUL 2004 WO 02/055810 PCT/SE02/00043 91 ing surface? is at least 30% of the thickness of the floorboard.

51. A locking system as claimed in any one of the . preceding claims, characterised in that the 5 depth of the tongue groove^ measured from the joint plane, is at least 2% greater than the corresponding extent of the tongue-

52. A locking system as claimed in any one of the preceding claims, characterised in that the 10 tongue ' has other material properties than the upper or the lower lip.

53. A locking system as claimed in any one of the preceding claims, characterised in that the upper lip is more rigid than the lower lip, 15 54 .' A locking system as claimed in any one of the preceding claims, characterised in that the upper and lower- lips are made of materials with different properties.

55. A locking system as claimed in any one of the 2 0 preceding claims, characterised in that the locking system also comprises a second mechanical lock which is formed of a locking groove which is formed on the underside of the joint edge portion supporting the tongue 25 and extends parallel with the joint plane, and a locking strip which is integrally attached to the joint edge portion of the board under the tongue groove and .extends along essentially the entire 3 0 length of the joint edge portion and has a locking component which proj ects from the strip and which, when two such boards are mechanically joined, is received in the locking groove ■ of the adjoining board, 35 56. A locking system as claimed in claim 55, characterised in that the locking strip projects beyond the joint plane. IPONZ 7 JUL 2004 WO 02/055810 PCT/SE02/00043 92

57. A locking system as claimed in any one of the preceding claims, charact'erised in that it is formed in a board having a core of wood-fibre-based material . 5 58. A locking system as claimed in claim 52, characterised in that it is formed in a board having a core of wood.

59. A floorboard having a core, a front side, a rear side and two opposite parallel joint 10 edge portions which are formed as parts of a mechanical locking system and of which one is formed as a tongue groove which is defined by upper and lower lips and has a bottom end, and the other is formed as a tongue with an upwardly directed por- 15 tion at its free outer end,, the tongue groove^ seen-from the joint plane, having the shape of an undercut groove with an opening, an inner portion and an inner locking surface, , and 2 0 at least parts of the lower lip being formed inte grally with the core of the floorboard, and the tongue ' having a locking surface which is adapted to coact with the inner locking surface in the tongue groove " of an adjoining floorboard 25 when .two such floorboards, are mechanically joined, so that their front sides are located in the same surface plane and meet at the joint plane directed perpendicular thereto, 3 0 wherein at "least the major part of the bottom end of the tongue groove, seen parallel with the surface plane? is located further away from the joint plane than is the outer end of the tongue^ and wherein the inner locking surface of the tongue groove is formed on the upper lip within the undercut portion of the tongue groove for coaction with IPONZ 7 JUL 2004 WO 02/055810 PCT/SE02/00043 Q 3 the corresponding locking surface , of the tongue, said locking surface being formed on the upwardly directed portion of the tongue to counteract pulling apart of two mechanically joined 5 boards in a direction perpendicular to the joint plane, and wherein the lower lip has a supporting surface for coact'ion with a corresponding supporting surface on the tongue at a distance from the bot- 10 torn end of the undercut groove, said supporting- surfaces being adapted to coact to counter act a relative displacement of two mechanically joined boards in a direction perpendicular to the surface plane, and wherein all parts of the portions, connected with the core^ of the lower lip, seen from the point where the surface plane and the joint plane intersect, are located outside a plane which is positioned further away from said point 20 than is a locking plane parallel therewith, which is tangent to the coacting locking surfaces of the tongue groove and the tongue where said locking surfaces are most inclined , relative to the surface plane, and and wherein the upper and lower lips and the tongue of the joint edge portions are design ed to enable disconnection of two mechanically joined floorboards by upward pivoting of one floorboard relative to the other about a pivoting 3 0 centre close to a point of intersection between the surface plane and the joint plane for disconnecting the tongue of one floorboard from the tongue groove of the other floorboard. 60. A floorboard as claimed in claim 59, char-35 acterised in that the upper and lower lips and tongue of the joint edge portions are designed to enable joining of two floorboards by one IPONZ 7 JUL 2004 WO 02/055810 PCT/SE02/00043 IPONZ 7 JUL 2004 94 floorboard, when the two floorboards are essentially in contact with each other, being pivoted downward relative to the other about a pivoting centre ' close to a point of intersection between the surface plane and the 5 joint plane for joining the tongue of one floorboard with the tongue groove of the other floorboard.

61. A floorboard as claimed in claim 59 or 60, characterised in that the undercut groove and the tongue are of such a design that a floor- 10 board which is mechanically joined with a similar board, is displaceable in a direction along the joint plane.

62. A floorboard as claimed in any one of claims 59-61, characterised in that the tongue 15 and the undercut groove are designed to enable con nection and disconnection of one board with and from another by pivoting one board relative to the other while maintaining contact between the boards at a point on the joint edge portions of the boards close to the inter-20 section between the surface plane ' and the joint plane.,

63. A floorboard as claimed in any one of claims 59-62, characterised in that the tongue and the undercut groove are designed to enable con- 25 nection and disconnection of boards by pivoting one board relative to another while maintaining contact between the boards at a point on the joint edge portions.of the boards close to the intersection between the surface plane . and the joint plane without essential 3 0 contact between the side of the tongue facing away from the 'surface plane and the lower lip. <•

64. A floorboard as claimed in any one of claims 59-62, characterised in that the tongue and the- undercut groove are designed to enable con- 35 nection and disconnection of boards by pivoting one board relative to another while maintaining contact between the boards at a point on the joint edge portions of the WO 02/055810 PCT/SE02/00043 95 boards close to the intersection between the surface plane and the joint plane and in essentially line contact between the sides of the tongue 'facing away from and respectively facing the surface plane 5 and the upper ' and respectively the lower lip.

65. A floorboard as claimed in any one of claims 59-64, characterised in that the distance between the locking plane and the plane parallel therewith, outside which all parts of the por- 10 tions, connected with the core, of the lower lip are located, is at least 10% of the thickness of the floorboard.

66. A floorboard as claimed in any one of claims 59-65, characterised in that the locking sur= 15 faces of the upper lip and the tongue form an angle to the surface plane of below 90° but at least ' 20°.

67. A floorboard as claimed in claim 66, characterised in that the locking surfaces of the 2 0 upper lip and the tongue form an angle to the surface plane of at least 3 0°.

68. A floorboard as claimed in any one of claims 59-67, characterised in that the undercut groove and the tongue are of such a design 25 ■ that the outer end of the tongue is located at a distance from the undercut groove along essentially the entire distance from the locking surfaces of the upper lip and the tongue^ which engage each other, to the coacting supporting surface of the 30 lower lip and the tongue^

69. A floorboard as claimed in claim 68, character! sed in that any surface portions with contact between the outer end of the tongue and the undercut groove . have a smaller extent along the 35 vertical plane than do the locking surfaces when two such boards aire mechanically joined. \ IPONZ 7 JUL 2004 WO 02/055810 PCT/SE02/00043 95

70. A floorboard as claimed in any one of claims 59-69, characterised in that the edge portions with their tongue and tongue groove are designed so that, when two floorboards are joined, there 5 is surface contact between the edge portions along- at most 3 0% of the edge surface of the edge portion supporting the tongue, measured from the upper side of the floorboard to its underside.

71. A floorboard as claimed in any one of claims 10 59-71, characterised in that the coacting supporting surfaces • of the tongue and the lower lip . are directed at such an angle to the surface plane that they are parallel therewith or "extend at an angle which is equal to or smaller than a 15 tangent to a circular arc which is tangent to the supporting surfaces . and has its centre at the point where the surface plane and the joint plane intersect, seen in cross-section through the board. 72 . A floorboard as claimed in any one of claims 20 59-71, characterised in that the coacting supporting surfaces of the tongue and the lower lip are set an angle of 0° to 3 0° to the sur face plane,,

73. A locking system as claimed in claim 72, 25 characterised in that the coacting supporting surfaces of the tongue and the lower lip are set at an angle of at least 10° to the surface plane.

74. A locking system as claimed in claim 72 or 73, 30 characterised in that the coacting supporting surfaces of the tongue and the lower lip are set at an, angle of at most 2 0° to the surface plane,

75. A floorboard as claimed in claim 71, char-35 acterised in that the coacting supporting surfaces of the tongue and the lower lip are set at essentially the same angle to the surface IPONZ 7 JUL 2004 WO 02/055810 PCT/SEO2/00043 97 plane as a tangent to a circular arc tangent to the supporting surfaces and having its centre at the point where the surface plane - and the joint plane intersect, seen in'cross-section through the board. 5 76. A floorboard as claimed in claim 71, char acterised in that the" coacting supporting surfaces of the tongue and the lower lip are set at a greater angle to the surface plane than a tangent to a circular arc which is tangent to the sup-10 porting surfaces engaging each other and positioned closest to the bottom of the undercut groove, and which has its centre at the point where the surface plane and the joint plane_ intersect.

77. A locking system as claimed in any one of claims 15 59-76, characterised in that the supporting surfaces,. designed for coaction, of the tongue and the lower lip are set at a smaller angle ■to the surface plane than are the coacting locking surfaces of the upper lip and the tongue. 20

78. A floorboard as claimed in claim 77, characterised in that the supporting surfaces^ designed for coaction, of the tongue and the lower lip are inclined in the same direction as, but 25 at a smaller angle to surface plane than, are the coacting locking surfaces of the upper lip and the tongue,

79. A floorboard as claimed in any one of claims 71-78, characterised in that the supporting 3 0 surfaces form an at least.2 0° greater angle to the surface plane than do the locking surfaces.

80. A floorboard as claimed in any one of claims 59-79, characte.rised in that the upper lip 35 extends to the joint plane and that at least parts of the inclined locking surface of the upper lip IPONZ 7 JUL 2004 WO 02/055810 PCT/SE02/00043 98 are located further away from the joint plane than is the supporting surface of the lower lip.

81. A floorboard as claimed in any one of claims 59-80, characterised in that the locking 5 surfaces of the upper lip and the tongue are plane within at least the surface portions which are adapted to coact with each other when two such boards are joined with each other.

82. A floorboard as claimed in claim 81, char-10 acterised in that the tongue has a guiding surface which is located outside the locking surface of the tongue^ seen from the joint plane^ and which has a smaller angle to the surface plane than does this locking surface. 15 83. A floorboard as claimed in any one of claims 59-82, characterised in that the lower lip has a guiding surface which is located closer to the opening of the tongue groove than is the supporting surface of the lower lip and which has a smaller 2 0 angle to the surface plane than does the supporting surface of the lower lip,

84. A floorboard as claimed in any one of claims 59-83, characterised in that the lower lip extends to or preferably ends at a distance from the 25 joint plane,

85. A floorboard as claimed in any one of claims 59-84, characterised in that the lower lip is shorter than the upper lip and ends at a distance from the joint plane, and that at least 30 parts of the supporting surfaces ■ of the lower lip and the tongue are located at a greater distance from the joint plane than are the inclined locking surfaces. of the upper lip and the tongue# 35 86. A floorboard as claimed in any one of claims 59-85, characterised in that the locking surface ' of the tongue is arranged at a dis- IPONZ 7 JUL 2004 WO 02/055810 PCT/SEO2/00043 tance of at least 0-. 1 times the thickness of the floorboard, seen from the tip of the tongue.

87. A floorboard as claimed in any one of claims . 59-86, characterised in that the locking sur- 5 face of the tongue is arranged at a.distance of at least 0.1 times the thickness of the floorboard from the tip of the tongue.

88. A floorboard as claimed in any one of claims 59-87, characterised in that the vertical 10 . extent of the locking surfaces coacting with each other is smaller than half the vertical extent of the undercut, seen from the joint plane and parallel with the surface plane.

89. A floorboard as claimed in any one of claims 15 59-88, characterised in that the locking surfaces, seen in a vertical section through the floorboard, have an extent which is at most 10% of the thickness of the floorboard.

90. A floorboard as claimed in any one of claims 20 59-89, characterised in that the length of the tongue, seen perpendicular away from the joint plane, ' is at least 0.3 times the thickness of the board.

91. A floorboard as claimed in any one of claims 25 59-90, characterised in that the joint edge portion . supporting the tongue and/or the joint edge portion ' supporting the tongue groove has/have a recess which is positioned above the tongue and ends at. a distance from the surface plane* 3 0 92. A floorboard as claimed in any one of claims 59-91, characterised in that the upper lip and the tongue ' have contact surfaces which in their locked state coact with each other and " which are positioned within an area between the joint 35 plane and the locking surfaces " of the tongue and the upper lip, which in their lock ed state coact with each other.. IPONZ 7 JUL 2004 WO 02/055810 PCT/SE02/00043 100

93. A floorboard as claimed in claim 92, characterised in that the contact surfaces are essentially plane.

94. A floorboard as claimed in claim 92 or 93, 5 characterised in that the contact surfaces are inclined upwards to the surface plane in the direction towards the joint plane.

95. A floorboard as claimed in claim 92 or 93, characterised in that the contact surfaces . 10 are essentially parallel with the surface plane.

96. A floorboard as claimed in any one of claims 59-95, characterised in that the lower lip of the tongue groove is flexible. 15 97. A floorboard as claimed in any one of claims 59-96, characterised in that it is formed as a snap lock which is openable by upward angling of one board relative to the other.

98. A floorboard as claimed in any one of claims 20 59-97, .characterised in that it is formed for joining a previously laid floorboard with a new floorboard by a pushing-together motion essentially parallel with the surface plane of the previously laid floorboard for snapping together the parts of the locking 25 system.

99. A floorboard as claimed in any one of claims 59-98, characterised in that the undercut groove, seen in cross-section, has an outer opening portion which tapers inward in the form of a funnel. 3 0 100. A floorboard as claimed in claim 99, char acterised in that the upper lip has a bevel at its outer edge furthest away from the surface plane,

101. A floorboard as claimed in any one of claims 35 59-100, characterised in that the tongue^ , seen in cross-section, has a tip which tapers. IPONZ 7 jul am WO 02/055810 PC T/SE02/00043 101

102. A floorboard as claimed in any one of claims 5 9-101, characterised in that the tongue, seen in cross-section, has a split tip with an upper and a lower . tongue part. 5 103. A floorboard as claimed in claim 102, characterised in that the upper and lower tongue parts of the tongue are made of dif ferent materials with different material properties.

104. A floorboard as claimed in any one of claims 10 59-103, characterised in that the tongue groove and the tongue are formed integrally with the floorboard,

105. A floorboard as claimed in any one of claims 59-104, characterised in that' the locking' 15 surfaces are set at a greater angle to the surface plane than a tangent to a circular arc which is tangent to the locking surfaces engaging each other at a point closest to the bottom of the undercut groove, and which has its centre at the point where the surface 20 plane and the joint plane intersect.

106. A floorboard as claimed in any one of claims 59-105, ' c h aracterised in that the upper lip is thicker than the lower lip.

107. A floorboard as claimed in any one of claims 25 59-106, characterised in that the minimum thickness of the upper lip adjacent to the undercut is greater than the maximum thickness of the lower lip adjacent to the supporting surface,

108. A floorboard as claimed in any one of claims 3 0 59-107, characterised in that the extent of the supporting surfaces is at most 15% of the thickness of the floorboard.

109. A floorboard as claimed in any one of claims 59-10 8, characterised in that the vertical 35 extent of the tongue groove between the upper and the lower lip* measured parallel with the joint plane " and at the outer end of the supporting IPONZ 1 JUL 2004 WO 02/055810 PCT/SE02/00043 102 surface, is at least 30% of the thickness ' of the" floorboard.

110. A floorboard as claimed in any one of claims 59-109, characterised in that the depth of 5 the tongue groove, measured from the joint plane^ is at least 2% greater than the corresponding extent of the tongue.

111. A floorboard as claimed in any one of claims 59-110, characterised in that the tongue 10 has other material properties than the upper or the lower lip.

112. A floorboard as claimed in any one of claims 59-111, characterised in that the upper lip is more rigid than the lower lip* 15 113. A floorboard as claimed in any one of claims 59-112, characterised in that the upper and lower * lips are made of materials with different properties.

114. A floorboard as claimed in any one of claims 2 0 59-113, character! sed in that the locking system also comprises a second mechanical lock which is formed of a locking groove which is formed on the underside of the joint edge portion supporting the tongue 2 5 and extends parallel with the joint plane, and a locking strip which is integrally attached to the joint edge portion of the board under the tongue, groove and extends along essentially the entire length of the joint edge portion and has a locking 3 0 component which projects from the strip and which, when two such boards are mechanically joined, is received in the locking groove ' of the adjoining board.

115. A floorboard as claimed in claim 11S, 35 characterised in that the locking strip projects beyond the joint plane. IP0N2 ? JUL 2004 WO 02/055810 PCT/SE02/00043 103

115. A floorboard as claimed in any one of claims 59-115, characterised in that it is formed in a board which has a core ' of wood-fibre-based material . 5 117. A floorboard as claimed in claim 116, character! sed in that it is formed in a board which has a core of wood.

118. A floorboard as claimed in any one of claims 59-117, charact.erised in that it is quadri- 10 lateral and has sides which are parallel in pairs.

119. A floorboard as claimed in claim 118, character! s.ed in that it has mechanical locking systems at all its four side edge portions. 12 0. A floorboard as claimed in claim 119, 15 characterised in that it has mechanical snap lock systems at two opposite side edge portions.

121. A floorboard as claimed in claim 110, characterised in that the mechanical locking system on two opposite short sides of the board has the 20 undercut groove and the tongue formed for lock ing together by snap function.

122. A floorboard as claimed in any one of claims 118-121, characterised in that the joint edge portion with the tongue. and/or the joint edge 25 portion with the tongue groove on one pair of parallel joint edge portions is/are formed with other material properties than the joint edge portion with the tongue and/or the joint edge portion with the tongue groove on the other pair of parallel joint edge portions. 3 0 123. A method of joining floorboards on a base, which have a core and a front side? a rear side and opposite parallel joint edge portions which are formed as parts of a mechanical locking-system and of which one is formed as a tongue groove (3 6) which 3 5 is defined by upper and lower lips and the other is formed as a tongue with an upwardly direct ed portion at its free outer end, IPONZ 7 Mm WO 02/055810 PCT/SE02/00043 104 the tongue groove having the shape of an undercut groove with an opening, an inner portion and an inner locking surface? the tongue having a locking surface which is 5 designed to coact with the inner locking surface in the tongue groove of an adjoining floorboard when two such floorboards are mechanically joined, so that their front sides are positioned in the same surface plane and so 10 that an upper part of their joint edge portions meets at a joint plane directed perpendicu lar thereto, and a riew floorboard being joined with a previously laid floorboard by putting together the joint edge 15 portions of these floorboards/ wherein the new board is moved with its one edge portion to the other joint edge portion of the previously laid floorboard until the tongue 2 0 of one board is partially inserted into the tongue groove ' of the other board, and wherein the new board is then angled, upwards relative to the previously laid floorboard for insertion of the outer end of the tongue formed on one 25 floorboard and having, at a distance' from its tip, its locking surface formed in an upwardly, directed portion of the tongue, into the tongue groove of the other board during contact between the upper and lower sides of the tongue 3 0 groove and the tongue ? until an upper part of the joint edge portions of the floorboards comes into contact, with each other, and wherein the new board is then angled downwards to the final position during continued insertion of the tongue 3 5 into the tongue groove to a position in which a supporting surface, which is formed on the underside of the tongue, is made to engage IPONZ 7 JUL 2004 WO 02/055810 PCT/SE02/00043 105 a corresponding supporting surface^ which is formed on the lower lip of the other board, so that the boards are mechanically locked together . both horizontally and vertically. 5 124. A method as claimed in claim 123, c h a r - a c t e r i s e d in that, during installation, the new board,- and its tongue^ is moved towards the tongue groove in the previously laid board. 12 5. A method as claimed in claim 123, char- 10 acterised in that, during installation, the new board, and its undercut groove, is moved towards the tongue on the previously laid board.

126. A method as claimed in any one of claims 123-125, characterised in that the upward

15. angling of the new board takes place while pressing the same towards the previously laid board.

127. A method as claimed in any one of claims 123-12 6, characterised in that the downward angling of the new board takes place during contact 20 between the upper joint edge portions of the new board and the previously laid board.

128. A method as claimed in any one of claims 123-12 7, characterised in that the new board is pressed against the previously laid one during- the 25 downward angling.

129. A method as claimed in any one of claims 123-128, characterised in that the upward angling is terminated by snapping the tongue 'into the tongue groove. 3 0 13 0. A method as claimed in claim 12 9, char acterised in that the snapping-in is carried out by essentially moving apart the upper and lower lips of the tongue groove.

131. A method as claimed in claim 13 0, c h a r - 35 acterised in that the snapping-in is carried out by a slight downward bending of the lower lip of the tongue groove. IPONZ 7 JUL 200<i WO 02/055810 PCT/SE02/00043 106

132. A method as claimed in any one of claims 123-131, characterised in that the new board, after installation, is moved along the previously laid board.to establish mechanical locking also along adjoin- 5 ing joint edge portions,

133. A floorboard substantially as described herein with reference to figure 21a to 21 b, 22, 24a to 24b or 25 or 26 or 33 or 34 or 35 or 37 or 39 or 40 or 41 or 42a to 42b or 43a to 43c or 44 or 45a to 45b or 46a to 46b or 47a to 47b or 48a to 48b or 49 or 50 or 51 a to 51f or 55.

134. A method of producing a floorboard as described herein with reference to figures 23a to 23b or 38a to 38d.

135. A locking system substantially as described herein with reference to any of figures 21 a to 22 or any of 24a to 37b or any of 39 to 57e.

136. A method of joining floor boards substantially as described herein with reference to figures 21 a or 22 or 24a or 25 or 26 or 27a to 27c or 28a to 28c or 29a to 29b or 30 or 31 a to 31 b or 32a to 32d or 33 or 34 or 35 or 36 or 40 or 41 or 42a to 42b or 43a to 43c or 45b or 46b or 47a or 48b or 51a to 51f or 52a to 52b or 53 or 54a to 54b or 56a to 56e or 57a to 57e. lpONz ' 7 JIJL 2004 </div>