BOARD PROVIDED WITH TONGUE AND GROOVE

Abstract: This invention relates to a board, which is made of a material based on wood, preferably particle board, which is suitable to use when laying down floor boards, the board having an essentially rectangular shape with two long sides and two short sides, and at least the one but preferably both short sides having a profile provided with tongues and grooves; which, when laying two boards together, makes possible to form an essentially smooth transition part between the boards. According to the invention the board is characterized in that the profile has the following design, seen from the top surface (11) of the board (19) in relation to which the tongue has a position above the groove: an obliquely backwards-directed, essentially straight portion (12), which passes over to a forwards-direct, rounded portion (13), which functions as a tongue; the inner part of the forwards-directed portion (13) passes over to a backwards-directed, rounded portion (16), which functions as a groove, and which has a forwards-directed part (17), which passes over to an obliquely backwards-directed, essentially straight portion (18), which extends to the underside of the board (19); the tongue (13) and the groove (16) are designed in that way that, when laying together two essentially uniform boards (19, 20), the other board (20) being reversed in relation to the first one (19), the tongues of the two boards will fit exactly into the grooves of the two boards, whereby the joint between the boards (19, 20), put together, gets such a strength that it could be placed between two adjacent beams in a floor with beams.

Description: BOARD PROVIDED WITH TONGUE AND GROOVE This invention relates to a board, which is made of a material based on wood, preferably particle board, which is suitable to use when laying down floor boards, the board having an essentially rectangular shape with two long sides and two short sides, and at least the one but preferably both short sides having a profile provided with tongues and grooves, which, when laying two boards together, makes possible to form an essentially smooth transition part between the boards. This type of particle boards are previously known. The problem with the known particle boards has been that the joint between two particle boards, put together, has not had sufficient strength. This fact has had the consequence that, when using the known particle boards to a floor with beams, the boards have had to be adapted in such a way that the joint between two particle boards, put together, has landed up on a beam. Otherwise the floor of particle boards could be broken when being loaded. Of course, this laying down of floor with particle boards becomes ineffective as well as expensive. This invention intends to remove the problems with known technique and to provide a board based on wood, preferably a particle board, which makes possible also to place the joint between two boards, put together, between two beams for a floor. This has been achieved by a board of the kind mentioned by way of introduction, which has the features mentioned in the claims. A preferred embodiment of the invention shall be described more closely below with reference to the accompanying drawings, where Fig. 1 shows a floor with beams, where the particle board according to the invention is used, Fig. 2 shows a joint between two particle boards, put together, according to the invention, and Fig. 3 shows the same picture as in Fig. 1 but with that difference that the particle boards have been drawn out a small distance from each other. In Fig. 1 is shown a plurality of rectangular particle boards 1 according to the invention, laid down on a great number of beams 2 for creating a floor with beams. The short sides 3 of the particle boards are provided with the new profile, which makes possible for the joint 4 between two boards 5, 6, put together, to be positioned between two adjacent beams 7, 8. Due to that fact the mounting of the particle boards can be made continuously, which means that, when there is a rest part of a board when finishing a row, it is possible to start the next row with that rest part. This fact leads to a very effective laying down of particle boards with a minimum of material wastage. Preferably, also the long sides of the particle boards are provided with the new profile, adjacent boards interfering with each other. Also that fact contributes to strengthen the joint between the short sides of the boards. The new profile of the short- and long sides of the particle boards, as has been mentioned, leads to an improved function of the joint between two particle boards, put together, and this fact has also that advantage that the number of screws for fastening the particle boards on the beams can be reduced in relation to known technique. In Fig. 2, 3 the special profile of the sides of the particle boards 9, 10 for making the strong joint possible is shown more closely. The profile has the following design, seen from the top surface 11 of the particle board in relation to which the tongue has a position above the groove: - An obliquely backwards-directed, straight portion 12, which forms an angle of 20- 30° with the vertical line, and which passes over to an obliquely downwards- and forwards- directed, rounded portion 13, which functions as a tongue, and which after the rounding extends essentially straightly backwards approximately at the middle of the depth, i.e. the thickness, of the particle board; - The mentioned extension 14 backwards has such a length that it reaches beyond a prolongation line 15 through the portion 12 towards the underside of the particle board and passes over to a backwards directed, rounded portion 16, which functions as a groove, and which has an obliquely downwards- and forwards-directed, straight portion 17, which passes over to an obliquely backwards-directed, straight portion 18, which extends to the underside of the board, and which has such a position that it essentially coincides with the mentioned prolongation line 15 through the portion 12. Furthermore, the profile is designed in that way that the two particle boards 19, 20, which shall be put together, are essentially uniform but are reversed when being put together so that the top surface of the one particle board 19 is directed upwards, whereas the top surface of the other board 20 is directed downwards. The advantage with this arrangement is that only one tool needs to be used, and that, principally, it would be possible to use optional side, directed upwards, when the floor is mounted. The obliquely bevelled parts 12, 18 of the profile portion of the one particle board, when co-operating with corresponding obliquely bevelled parts as of the profile portion of the other particle board 20, has the effect that the forces arising when loading the joint are distributed out to all parts of the joint with an increased strength as a result. To this high strength of the mentioned joint contributes also that fact that the new profile is well counterbalanced. This fact appears from Fig. 3, where it can be seen that the floor profile is "symmetrical" with regard to the line 15, i.e. the volume of the tongue 13 is essentially the same as the volume of the groove 16. When putting together the short and long sides of the two particle boards, glue is applied between the two joint profiles, the glue strings being forced out and round in the joint by the plough-formed profile parts, which results in a strong glue joint. In the text has been used the expressions "backwards-directed" and "forwards- directed. With the first-mentioned expression is meant the direction of the arrow 21 in Fig. 3, whereas the direction of the arrow 22 relates to the other expression. The invention is of course not limited to the mentioned and shown embodiment but can be modified within the scope of the following claims.

Claims: Claims 1. A board, made of a material based on wood, which is suitable to use when laying down floor boards, the board having an essentially rectangular shape with two long sides and two short sides, and at least the one but preferably both short sides having a profile provided with tongues and grooves, which, when laying two boards together, makes possible to form an essentially smooth transition part between the boards, c h a r a c t e r i z e d in that the profile has the following design, seen from the top surface (11) of the board (19) in relation to which the tongue has a position above the groove: - An obliquely backwards-directed, essentially straight portion (12), which passes over to a forwards-directed, rounded portion (13), which functions as a tongue; - The inner part of the forwards-directed portion (13) passes over to a backwards- directed, rounded portion (16), which functions as a groove, and which has a forwards- directed part (17), which passes over to an obliguely backwards-directed, essentially straight portion (18), which extends to the underside of the board (19); - The tongue (13) and the groove (16) are designed in that way that, when laying together two essentially uniform boards (19, 20), the other board (20) being reversed in relation to the first one (19), the tongues of the two boards will fit exactely into the grooves of the two boards, whereby the joint between the boards (19, 20), put together, gets such a strength that it could be placed between two adjacent beams in a floor with beams. 2. A board according to claim 1, c h a r a c t e r i z e d in that the portion (12) close to the top surface (1 1) of the board (19) forms an angle of 20-30° with the vertical line, that the tongue (13) has an extension (14) backwards with such a length that it reaches beyond an imagined prolongation line (15) through the mentioned portion (12) in the direction towards the underside of the board (19), and that the portion (18), extending to the underside of the board (19), has such a position that it essentially coincides with the mentioned prolongation line (15). 3. A board according to claim 2, c h a r a c t e r i z e d in that the mentioned profile is counterbalanced in such a way that the profile is essentially "symmetrical" with regard to the line (15), i.e. the volume of the tongue (13) is essentially the same as the volume of the groove (16). 4, A board according to any one of the preceding claims, c h a r a c t e r i z e d in that also the two long sides of the board has the new profile.

Inventors: NORDEBRING BENGT-OVE, NORDEBRING, BENGT-OVE
Applicants: BYGGELIT AB, NORDEBRING BENGT OVE, NORDEBRING, BENGT-OVE
Application year: 1997
Main classification: E04F15
IPC codes: E04F15