Pair of boards, wood composite panel and method for producing the same

Description

[0001] The invention relates to a pair of boards comprising two boards connected to each other along their longitudinally profiled narrow sides, having the features of the preamble of claim 1.

[0002] The invention further relates to a wood composite panel comprising at least one layer of pairs of boards connected to one another at their profiled longitudinal narrow sides.

[0003] Finally, the invention also relates to methods for producing the said pairs of boards and wood composite panels.

[0004] Single-layer or multi-layer wood composite panels made of cross-laminated timber or sawn timber are known from the state of the art. Multi-layer composite panels made of cross-laminated timber, also known as "cross-laminated timber," are currently made exclusively from softwood and are preferably constructed of three layers, usually glued crosswise to each other. Individual layers can also be replaced by other wood materials such as oriented strand board (OSB) or laminated veneer lumber.

[0005] Single-layer or multi-layer wood composite panels offer the advantage that they can be manufactured as a large-format "carpet," from which components of any surface area can subsequently be sawn or cut. In these processes, the individual boards are arranged lengthwise and glued together along their narrow sides in a press. The press must apply a "surface pressure" to the visible surfaces of the interconnected boards and usually also a "lateral pressure" to the narrow sides of the outermost boards of the composite. The producible format of the carpet is therefore limited to the size of the press, in particular its maximum pressing width.

[0006] From an economic perspective, it is generally desirable to use so-called side boards for individual or all layers of the wood composite panel. To make the side boards easier to join together, they are first formatted to a rectangular cross-section, which generates waste. If the side boards are left with or without their wane and trapezoidal cross-section, they form sloping interfaces along adjacent longitudinal narrow sides. Pressing such side boards together is particularly challenging, and lateral pressure must be applied in any case. Particular care must be taken to coordinate surface pressure and lateral pressure to prevent cupping, warping, or similar problems at the interfaces during or after the pressing process.EP 3 079 870 B1 describes such a process, in which the dried side boards are first split lengthwise along their centerline to reduce warping. This additional splitting results in twice as many pieces (boards) that require further handling and processing, resulting in additional costs for sawing, loss of the joint due to splitting in the centerline, additional adhesive, and increased processing time. For the reasons stated above, such wood composite panels can only be used in high-quality products, for example, for furniture and interior design.

[0007] It is the object of the present invention to provide pairs of boards and single- or multi-layer wood composite panels as well as methods for their production, which overcome, or at least reduce, the problems of the prior art described above.

[0008] This object is achieved by providing pairs of boards having the features of claim 1, as well as wood composite panels having the features of claim 10, by a method for producing a pair of boards according to claim 13, and by a method for producing wood composite panels having the features of claim 18. Advantageous embodiments of the invention are set forth in the subclaims, the following description, and the drawings.

[0009] A pair of boards according to the invention comprising two boards connected to one another along their longitudinally profiled narrow sides, wherein the profiling is preferably a profiling already carried out in the sawmill when the boards are fresh, is characterized in that the boards originate from the same tree trunk, preferably from the same tree trunk cut to a standard raw wood length, with essentially the same moisture content and taper, and are cut from mutually corresponding layers of the tree trunk that are opposite one another with respect to a longitudinal axis of the tree trunk, wherein a guide bevel is formed on the boards to be connected, wherein the two boards have been connected when the boards are fresh and wherein the two boards are arranged in a neutral annual ring position with respect to one another.

[0010] Such a pair of boards is for example in Fig. 6shown and is described in more detail below. Even when the pair of boards is joined together after production, it is clear that the boards were profiled when fresh and come from opposite sides of the same tree trunk. The profiling when fresh can be recognized from their shrinkage behavior. The fact that the boards come from the same tree but are opposite each other can be recognized by their very similar density, a similar growth ring pattern with essentially the same pattern of growth ring widths, the same moisture content, the same quality and spacing of branch formation during the annual growth, and the same shrinkage behavior. These properties can be inspected or assessed, for example, on the end face (also known as the "top face" in technical jargon because it is on the side of the trunk facing the treetop) and the stem face (the stem face is opposite the end face, i.e. it faces the rootstock of the tree trunk) of the boards.be measured comparatively.

[0011] The two boards of the pair of boards were joined together while they were still fresh. Because the boards are joined while they were still fresh in the sawmill and come from the same trunk and the same, opposite layer in the tree trunk, they have essentially the same quality, taper and, in particular, roughly the same moisture content as a natural product. The same or at least very similar moisture content of the two boards is a prerequisite for successful bonding while wet, e.g. with PU adhesive. Bonding with PU adhesive can be supported in the process by using microwave ovens and / or other measures for surface heating. Furthermore, the boards can be two narrow side boards, whereby by joining these narrow side boards while they are still fresh in the sawmill, a wider pair of boards is immediately produced.This offers the advantage that for further processing it is no longer the individual boards that need to be manipulated, but the pair of boards, which reduces the number of items to be handled by half. This means that a processing system can handle twice the output without changing the system's cycle speed. This is particularly advantageous because industrial sawmills are constantly demanding higher volumes. Furthermore, processing the wider, more stable pairs of boards causes fewer disruptions to the system's operation because the pairs of boards are parallel and straight on the outside, unlike individual boards which are often bent. This reduces operating costs considerably. It is also possible, for example, to process boards that are around 50% wider, measuring around 15 cm, instead of two narrow boards each measuring 10 cm. This way, a pair of boards 30 cm wide can be produced with the same quality across its width, thus saving around 10%.To achieve a 40 - 50% increase in yield.

[0012] Preferably, the pair of boards is provided with parallel guide bevels on both of its narrow longitudinal sides.

[0013] In the pair of boards according to the invention, the two boards are arranged in a neutral growth ring position relative to each other. Joining the "twin" boards while still fresh in the sawmill ensures that the correct boards (from the same opposite layer of the same tree trunk) are matched. This also eliminates subsequent manual (through visual inspection) or automatic (camera, etc.) matching, thus eliminating a source of error from the outset. Thus, the matching boards can be arranged in a neutral growth ring position, thus adhering to the craft rule for solid wood—that is, arranging the boards to be joined in a neutral growth ring position—which leads to neutral shrinkage and swelling of the joined boards without tension or warping. Thanks to the invention, this can now be implemented industrially at previously unattainable low costs.Arranging in a neutral growth ring orientation means that adjacent boards are arranged so that the growth ring sections of the boards are arranged next to each other in opposite curvatures. This is visible on the pair of boards at the end and buttress sides. Arranging the two boards in a neutral growth ring orientation and profiling and joining them while fresh also eliminates incorrect bonding of the board pairs with the slanted tree edge. The boards exhibit conformal shrinkage and swelling ("negative shrinkage"), so that less significant stresses arise in the bonded joints over the service life of the board pairs. The well-known higher quality of side boards, i.e., boards cut from the tree side, e.g.as regards their higher modulus of elasticity, and the use of the side boards for the pair of boards made possible by the invention makes it possible to provide pairs of boards with conformal strength from the side boards that were previously considered to be rather inferior (because they are thin and narrow with a large number of pieces and have an inevitable tree edge).

[0014] In a particularly preferred embodiment of the pair of boards according to the invention, the profiles of the boards at the common longitudinal connection are formed as complementary dovetail profiles, wherein the longitudinal connection is optionally provided with an adhesive, and wherein, preferably, when multiple dovetail profiles are formed on each board, adjacent dovetail joints are formed inversely to one another. For example, when multiple dovetail profiles are formed on each board, adjacent dovetail joints for approximately 10 mm board thickness each (multiple thickness) can be formed inversely to one another. The dovetail profiles are preferably milled in the curve of the tree edge.Through these measures and, if necessary, further optimization, when joining the two profiled boards by sliding them together with continuous guidance on the inventively continuously usable guide bevel, formed by profiling in the curve of the tree edge, a very good mechanical connection is created by form-fitting, which makes it possible to reduce the use of adhesive, e.g., by applying only one line of adhesive in the middle or one on each of the outer sides. Furthermore, e.g.Depending on the quality and requirements, when processing the pairs of boards into multi-layer composite panels with visible surfaces on the outside and middle layers on the inside, the boards can be sorted during the profiling process with regard to more or less wane or the amount of adhesive can be portioned out (fully or through every or only every second line of adhesive) in order to produce a fully glued connection without wane, that is the tree bark edge, to form the pair of boards for the visible surfaces, or, for example, for certain low qualities, such as middle layers, less adhesive can be used when the boards have a low wane, or the boards can be connected only by pushing the dovetail profiles of the boards into one another. Such qualities can be used as middle layers for the composite panels, in particular for cross-laminated timber.By milling the dovetail profiles in the curve of the tree edge, one mainly uses their shape from the previously milled edge / longitudinal side of the board practically outside the diagonal connecting line of the corner points and minimizes the wood loss when creating the mechanical connection of the two joining partners, thus increasing the yield.

[0015] The width of each board in the pair of boards is expediently at least 30, preferably at least 40 mm at its narrow end, with the board width preferably being as large as possible, e.g. selectable in 1 mm increments. The 30 mm minimum width is measured from the point at which the board is at least grazed by the saw. Conventionally, the board width is at least 80 mm and is stepped in at least 20 mm increments. Furthermore, boards with wane edges could hardly be used in the prior art. This meant that only thin side boards could be produced. For this reason, to make better use of the tree trunk, particularly for larger diameters, two side boards were usually cut from each side of the tree trunk, making a total of four boards. During further processing into pairs of boards, the many thin boards (double the number of boards) require twice the workload.The invention makes it possible to process tapered side boards with a slanted wane edge even in greater thicknesses. This, in turn, allows the individual side boards to be produced much thicker than conventionally, in particular at least twice as thick as conventional boards, and thus with a higher quality. Furthermore, the conventional sawing joint is avoided, thus increasing yield. Furthermore, even thicker pairs of boards can be produced from the thicker boards without twisting or shrinkage by means of dovetail joints, preferably while still fresh.

[0016] In a further preferred embodiment of the pair of boards according to the invention, the boards are profiled with respect to one another without overlapping, and the guide bevels serve as stops for the formation of further dovetail profiles for connecting pairs of boards using the dovetail profiles at the longitudinal joints. The advantage of this embodiment lies in the possible production of wooden panels of any width from these pairs of boards without the need for a press. These wooden panels can be extended, preferably in predetermined system widths, by finger jointing as more stable structural timbers connected by at least one adhesive joint, and can be used for longitudinal, middle, and cross layers, or for visible or cover layers for wood composites.

[0017] In an alternative embodiment of the pair of boards according to the invention, each board has a guide bevel incorporated in the fresh state, and the pair of boards has been profiled on its longitudinal narrow sides with complementary folding profiles in the dry state, preferably with an overlap of 0.3 to 0.6 mm. A wood composite panel produced from such pairs of boards connected to each other along their longitudinal narrow sides is characterized by the fact that adjacent pairs of boards are arranged in a neutral annual ring position. To produce this wood composite panel, the pairs of boards are laid in a layer width in a neutral annual ring position according to traditional craftsmanship and are pushed through the press in time with the width of a press, preferably a high-frequency press, in a continuous flow with a short pressing time. From this "endless" wood composite panel, wood composite panels of any width can be cut as required, e.g.in system widths of 250, 500, 750, 1000, 1250, 2500 mm, and then further processed.

[0018] In the wood composite panels according to the invention, consisting of at least two superimposed layers of pairs of boards, the pairs of boards of a respective layer are provided with adhesive on their profiles, and adhesive is applied to the surfaces of adjacent layers of pairs of boards, with the pairs of boards of a respective layer being arranged parallel to one another. This allows the layers of the wood composite panel to be pressed together and bonded together in a single work step simply by applying surface pressure to the outer layers, allowing a panel width to be produced within the cycle width of the press, i.e., within the press's feed length.The wood composite panel produced in this way is already fully bound and practically manufactured in a continuous process, whereby by placing the pairs of boards of the same layers parallel to each other and applied with adhesive to the feed table, a further cycle width is already available ready for further pressing in the feed, in order to produce endless panels, as in . Fig. 4 shown. From these panels, the desired width of the wood composite panel can be cut from the continuous wood composite panel as required.

[0019] A suitable embodiment of the wood composite panel according to the invention comprises at least three superimposed layers of pairs of boards according to the invention, wherein the pairs of boards of a respective layer are provided with adhesive on their profiles and adhesive is applied to the surfaces of adjacent layers of pairs of boards, wherein the pairs of boards of adjacent layers are arranged crosswise to one another.

[0020] The invention also relates to a method for producing a pair of boards, which is characterized by cutting two boards from the same tree trunk, preferably from the same tree trunk cut to a standard raw wood length, in the fresh state of the tree trunk from mutually corresponding layers of the tree trunk which are opposite one another with respect to a longitudinal axis of the tree trunk, forming profiles on at least one of the longitudinal narrow sides of the boards in the fresh state of the boards, arranging the two boards so that the boards are mirrored to one another with respect to a central transverse axis, and joining the boards of the longitudinal narrow sides by sliding them into one another along their profiles, preferably in the fresh state of the boards, optionally with prior application of adhesive to the profiles.

[0021] Preferably, the pair of boards is provided with parallel guide bevels on both of its narrow longitudinal sides and the two boards are arranged in a neutral annual ring position with respect to each other.

[0022] Precise and rapid production of the pairs of boards on an industrial scale is achieved by forming the profiles of the boards at the common longitudinal joint as complementary dovetail profiles. Preferably, when forming multiple dovetail profiles on each board, adjacent dovetail joints are formed inversely to one another, in contrast to the prior art, in which the dovetail joints are formed identically to one another. The advantage of the inverted formation of dovetail profiles according to the invention is that the breaking off of the heads or splintering of dovetail parts in the groove at the dovetail corner can be avoided, which occurs more easily in the prior art, particularly on one side of the beveled edge.To achieve the above-defined objective, it is further preferred that the boards are profiled in relation to one another without overlapping, that the guide bevels with stop are used for the formation of the dovetail profiles and further for controlled guidance on the continuously inserted guide bevel at the stop for sliding into one another without offset and deviations.

[0023] In a preferred embodiment of the method according to the invention for producing a pair of boards, each board is provided with a guide bevel in the fresh state and the pairs of boards are profiled in the dry state on their longitudinal narrow sides 5 with complementary folding profiles, preferably with 0.3 to 0.6 mm overlap of the folding profiles.

[0024] A preferred embodiment of the pair of boards according to the invention is characterized in that the geometry of the dovetails in the tangential wood of the annual rings in the rounded kerb at the root of the tails, preferably with a minimum width of 6 mm, is designed with greater strength for greater loading by transverse forces, wherein the central dovetails are approximately twice as high as the laterally outer dovetails in the curve of the kerb. For example, the central dovetails with the extended flanks have head heights of approximately 4.5 mm, 6 mm or 8 mm, and the laterally outer dovetails have head heights of approximately 2 mm, 2.5 mm, 3 mm or 4 mm. This reduces the risk of breakage due to the wedge effect on the tangential annual rings, especially in the softer early wood ring. If the dovetails in the standing wood of the radial annual rings in the trapezoidal center plank, e.g.the trapezoidal boards Z with Z`, see . Fig. 15 , are formed at the root about 3 mm wide and about 2 mm high, the boards can be connected by dovetails in a preferably grid of e.g. 10 mm as a multiple thickness to at least one pair of boards from the wedge-shaped center plank Z with Z` again in a parallel shape.

[0025] The invention also relates to a method for producing wood composite panels from pairs of boards produced according to the method for producing pairs of boards described above. This method for producing wood composite panels comprises: the flattening of the pairs of boards, the formation of complementary inclined profiles with folding profiles of opposite shape on the mutually facing narrow longitudinal sides of the pairs of boards, the arranging of the pairs of boards next to each other, the application of adhesive to the narrow longitudinal sides of the pairs of boards, the joining of adjacent pairs of boards at their narrow longitudinal sides, optionally with simultaneous hooking of the folding profiles, and the pressing of the joined pairs of boards.

[0026] The inventive method for producing wood composite panels provides for the production of multi-layer wood composite panels with at least two layers. The pairs of boards are arranged in at least two superimposed layers and bonded together, with the pairs of boards in each layer being arranged parallel to one another and the adjacent layers being bonded together in the same work step. These wood composite panels can be produced with very little adhesive and are therefore environmentally friendly. By arranging adjacent boards of the pairs in a neutral growth ring position, shrinkage / swelling is reduced, particularly at the bonded joints, even later, after installation. The neutral growth ring position results in little or no stress at the angled joints on the long side walls (which are formed from the tree edges).This also applies to the surface bonding of adjacent layers on pairs of boards, for which homogeneous side boards with their relatively flat annual rings are ideally suited.

[0027] According to the invention, several multi-layer wood composite panels are joined together by means of finger joints, either in panel width or in predefined required widths or system widths. The wood composite panels are stacked in at least two layers. To produce the pairs of boards, the boards are first sorted to their raw lengths, free of knots, or knotted parts of the boards are trimmed. The multi-layer wood composite panels are then cut into glued squared timbers. The finger joints can be subjected to a standardized tensile test, allowing the quality-assured squared timbers to be used as long, stable beams / girders.

[0028] Further details, features, and advantages of the invention will become apparent from the following explanations of exemplary embodiments schematically illustrated in the drawings. In the drawings: Fig. 1 in a cross-sectional view a section of a single-layer wood composite panel according to the invention according to a first embodiment; Fig. 2 in a cross-sectional view a section of a single-layer wood composite panel according to the invention according to a second embodiment; Fig. 3A to Fig. 3D a pair of boards according to the invention in a first embodiment in a cross-sectional view ( Fig. 3A ), a view from above ( Fig. 3B ), a side view from the left ( Fig. 3C ), and a perspective view from the top right ( Fig. 3D ); Fig. 4each in a cross-sectional view a section of a single-layer, two-layer and three-layer wood composite panel according to the invention based on the second embodiment; Fig. 5A and Fig. 5B a board for a pair of boards according to the invention without ( Fig. 5A ) and with ( Fig. 5B ) Folding profile in a mixed perspective view, with the profile for connecting the boards shown inserted; Fig. 6 the production of a pair of boards according to the second embodiment. Fig. 7 and Fig. 8 a further embodiment of a single-layer wood composite panel according to the invention in cross section; Fig. 9A one made of single-layer wood composite panels from Fig. 7 and Fig. 8 manufactured three-layer plywood wood composite panel in cross section; Fig. 9B a variant of the three-layer plywood composite panel from Fig. 9A in cross section; Fig. 10 a side board cut from a fresh tree trunk in cross section; Fig. 11another side board cut from a fresh tree trunk in cross section; Fig. 12 another side board cut from a fresh tree trunk and then split in cross section; Fig. 13 a pair of boards connected by several dovetail profiles; Fig. 14 the cross-section of boards cut from a medium-thickness tree trunk; Fig. 15 a sectional view of the division of a tree trunk according to aspects of the present invention with the parallel pairs of boards made of sapwood and pairs of boards made of the wedge-shaped center plank; Fig. 16A to 16F the production of pairs of boards and composite wood panels made from thin tree trunks, so-called weakwood; Fig. 17A to 17F the alternative production of pairs of boards and composite wood panels made from thin tree trunks, so-called weak wood; and Fig. 18A to 18E the production of a pair of boards according to Fig. 13 .

[0029] Figure 1 shows a cross-sectional view of a section of a single-layer wood composite panel 1 according to the invention according to a first embodiment. The wood composite panel 1 is made of several boards 2 placed against one another, the side boards of a block-shaped substrate 3 (see Fig. 6), for example, a raw log. The boards 2 originate from the same tree trunk, preferably from the same tree trunk cut to a standard raw log length, and are cut from corresponding layers of the tree trunk that are opposite one another with respect to a longitudinal axis of the tree trunk. The boards 2 have a trapezoidal cross-section, with longitudinal narrow sides 5 forming the legs of the trapezoidal cross-section, and with adjacent boards 2 arranged mirror-imaged relative to one another with respect to a central transverse axis 6. The boards 2 are connected to one another with essentially the same wood grain direction along their longitudinal narrow sides 5 profiled in the longitudinal direction 4. The outer visible surfaces of the interconnected boards 2 form a top side 7 and a bottom side 8 of the wood composite panel 1. The boards 2 have a board thickness 11. The longitudinal direction 4 is in accordance with Figure 1normal to the sheet plane. Two boards 2 are connected to form a pair of boards 14 (see Fig. 3 By placing the pairs of boards 14 next to one another, a surface of boards 2 that is essentially infinitely long in the transverse direction, a so-called "carpet", can be provided only by applying surface pressure, i.e., without additional lateral pressure.

[0030] The boards are profiled along their longitudinal direction 4 on the longitudinal narrow sides 5, whereby the profiling is preferably a profiling already carried out in the sawmill when the boards 2 are still fresh. The profile of the longitudinal narrow sides 5 has a folding profile 9 with a folding profile angle SW of less than or equal to 90 degrees, in the present example according to Figure 1 at an angle of approximately 60 degrees. In addition, the folding profiles 9, as shown in Figure 1shown, be offset from the central transverse axis 6. The distance from the central transverse axis 6 can be approximately 0.1 mm to 0.8 mm, preferably approximately 0.3 mm to 0.6 mm, particularly preferably approximately 0.4 mm to 0.5 mm. This creates an overlap 12 between adjacent boards 2 after the boards 2 have been placed next to one another and before the boards 2 are pressed together to form board pairs 14 or to form the wood composite panel 1. This overlap 12 can - according to the previously mentioned examples for the distance from the central transverse axis 6 - be approximately 0.1 mm to 0.8 mm, preferably approximately 0.3 mm to 0.6 mm, particularly preferably approximately 0.4 mm to 0.5 mm. 2. The profile of the longitudinal narrow sides 5 can have more than one folding profile 9, preferably two folding profiles 9, wherein the folding profile angles SW of all folding profiles 9 are less than or equal to 90 degrees.The folding profile angles SW of the folding profile 9 or of all folding profiles 9 are, for example, 80 angular degrees or less, preferably 70 angular degrees or less.

[0031] Figure 2 shows a cross-sectional view of a section of a single-layer wood composite panel 10 according to the invention according to a second embodiment. The wood composite panel 10 according to the second embodiment is essentially similar to the wood composite panel 1 according to the first embodiment, with the difference that two adjacent boards 2 are joined along their mutually contacting longitudinal narrow sides 5 via a dovetail profile 13 to form a pair of boards 14 (see Fig. 3 ) are connected to each other. Alternatively, the boards 2 to be joined to form pairs 14 can be equipped with two or more than two, for example three, four or five, dovetail profiles 13. After connecting the adjacent boards 2 to form a pair 14 (see Figures 3 to 6 ), each pair of boards 14 has a profile with a guide bevel 17 along its outer longitudinal narrow sides 5 (see Fig. 5A ) or a folding profile 9 with a folding profile angle SW of less than or equal to 90 degrees, in the present example according to Figure 2 approximately 60 degrees. At folding profile angles SW below 80 degrees, a complementary hooking effect is created.

[0032] In this exemplary embodiment, the pair of boards 14 is also made from two boards 2 connected to one another along their longitudinal narrow sides 5 profiled in the longitudinal direction 4, wherein the boards 2 originate from the same tree trunk and are cut from corresponding layers of the tree trunk that are opposite one another with respect to a longitudinal axis of the tree trunk. The profiling is preferably already carried out in the sawmill when the boards 2 are still fresh. The boards 2 are arranged opposite one another in a mirrored manner with respect to a central transverse axis 6. For example, the boards 2 are side boards of a pair of boards 14 made from the same log layer of a raw round timber (see Figure 6) and connected to each other via a dovetail profile 13. These two boards 2 then have a favorable annual ring position relative to each other and a substantially identical quality in terms of fiber and moisture content. After joining the boards, the pair of boards 14 has a substantially rectangular and stable shape, for example, according to the Figures 3A to 3D , without the risk of bending. By profiling and parallel placement of such pairs of boards 14, for example according to the Figures 2 to 6 , a substantially infinite surface in the transverse direction, a so-called "carpet", can be provided, forming a wood composite panel 10, 20 or 30.

[0033] If, when pressing the boards 2 to form the wood composite panel 1 or 10, a surface pressure FD (see Figure 4, FD represented by the multitude of parallel arrows) is applied to the top side 7 and / or the bottom side 8 of the wood composite panel 1 or 10, the folding profiles 9 prevent the boards 2 from being pushed apart transversely to the direction of the contact pressure, i.e., essentially transversely to the existing direction of action of the surface pressure FD. Any overlaps 12 that may have existed prior to pressing are deformed and "ironed out" by the action of the pressing force, so that a flat and parallel top side 7 and bottom side 8 are created. Preferably, the profiling of the boards 2 is carried out in such a way that an overlap 12 between adjacent boards 2 only occurs due to the dimensioning of the folding profile 9. In Fig. 2 For the sake of completeness, however, overlaps 12 on adjacent boards 2 are shown, which are caused by the design of the folding profile 9 and the dovetails 13. Even in the embodiment of the wood composite panel 10 according to Fig. 2only the application of a surface pressure FD is required, but not an additional lateral pressure.

[0034] With reference to Figure 4The single-layer wood composite panel 10 can alternatively be formed as a two-layer wood composite panel 20, a three-layer wood composite panel 30, or as a wood composite panel with more than three layers, for example, four, five, six, seven, eight, nine, ten, or more than ten layers. The top side 7 of the wood composite panel 10, 20, or 30 is formed from the outer visible surfaces of the uppermost layer of pairs of boards 14 made of interconnected boards 2, and the underside 8 of the wood composite panel 10, 20, or 30 is formed from outer visible surfaces of the lowermost layer of pairs of boards 14 made of interconnected boards 2. In the case of a three-layer wood composite panel 30, a middle layer panel 15 can be formed from side boards, center boards, center planks, squared timber planks, cross-timber planks, and / or center planks of a block-shaped substrate 3. It should also be mentioned that the thickness of the individual layers of the wood composite panels can be relatively small, e.g. only 20 mm thick.Such thin layers are called lamellas, which are processed into multilayer boards that exhibit high rigidity and strength. It has been shown that the quality of these multilayer boards is higher when pairs of boards are used instead of individual boards.

[0035] Fig. 5A and Fig. 5B show two boards 2 joined together to form a pair of boards 14, for example the one according to Figure 3 , in a mixed perspective view, wherein the dovetail profile 13 for connecting the boards 2 is shown inserted. The boards 2 are profiled without overlapping with respect to one another, and the guide bevels 17 serve as stops for the formation of further dovetail profiles for connecting pairs of boards 14 by means of the dovetail profiles at the longitudinal connections 13.

[0036] Figure 6 shows a method for producing such a pair of boards 14 from boards 2.

[0037] The process is particularly efficient and cost-effective. The two boards 2 represent a "right" and a "left" side board of a block-shaped substrate 3, for example, a raw log as described above. The two boards 2 are sawn from the same core layer of the substrate 3 while still fresh. One of the boards 2 is then turned, and the longitudinal narrow sides 5 of the boards 2 to be joined are each profiled with opposing dovetail profiles 13. The boards 2 are guided along a guide bevel direction 16 at the stop by guide bevels 17 milled into the boards 2. The profiling of the boards 2 is preferably carried out while the boards 2 are still fresh. The boards 2 are then joined, with or without PU adhesive, to form the pair 14 by sliding the complementary partners of the dovetail profiles 13 into one another.The boards 2 are pushed into one another at a speed relative to one another, i.e. the boards 2 can be moved in opposite directions, or one of the boards 2 can be stationary, or the boards 2 are moved in the same direction at different speeds. If the boards are freshly bonded, the bonding on the narrow longitudinal sides 5 can be optimized using microwaves to promote a uniform reaction in the bond joint. Each pair of boards 14 is connected along its center and can be profiled on the remaining outer narrow longitudinal sides 5 with one or more folding profiles 9. Before further joining and pressing to form a wood composite panel 10, 20 or 30 according to the invention, the pairs of boards 14 are preferably dried. Optional storage of the pairs of boards 14 in a warm / heated environment supports the reaction in the bond joint.That the boards were profiled and joined while fresh is evident from their shrinkage behavior. That the boards originate from the same tree, located opposite each other, can be determined through analysis, for example, by their very similar knot formation in the knot pattern of the board surfaces with the spacing of annual growth, their comparable density, similar annual ring patterns with approximately equal annual ring widths, the same moisture content and quality typical of a tree trunk, and comparable shrinkage behavior. The dovetail joint creates a positive connection between the 2 boards.

[0038] Preferably, the two boards 2 of the pair of boards 14 are arranged in a neutral annual ring position with respect to one another.

[0039] The width of each board 2 at its narrow end, at least as cut by the saw, is at least 30, preferably at least 40 mm, wherein the board width is preferably selected to be as large as possible, e.g. in 1 mm increments.

[0040] An embodiment of a method according to the invention for producing a wood composite panel 1, 10, 20, or 30 is described below by way of example: In a first method step, a plurality of boards 2 are provided. Two adjacent boards 2 of the provided boards are made of the same block-shaped substrate 3 and are cut, in particular, while the substrate 3 is still fresh, which is preferably a tree trunk cut to a standard raw wood length, and are joined together to form pairs of boards 14, as described above.

[0041] In a next method step, each board 2 is profiled along its longitudinal narrow sides 5 while it is still fresh, with profiles which, according to the above description, have at least one dovetail profile 13 and / or one or more folding profiles 9 with a folding profile angle SW of less than or equal to 90 degrees. If pairs of boards 14 are provided, the boards 2 of these pairs of boards 14 are connected to one another along their mutually contacting longitudinal narrow sides 5 via at least one dovetail profile 13, and the pairs of boards 14 are each profiled along their outer longitudinal narrow sides 5 with a profile which, according to the above description, has one or more folding profiles 9 with a folding profile angle SW of less than or equal to 90 degrees. The folding profiles 9 can be milled, with preferablyA narrow edge is first pre-milled into the pair of boards 14 as a guide bevel 17, which can subsequently serve as a stop for the milling process of the folding profiles 9 (see . Figure 6 ). The dovetail profiles 13 and the folding profiles 9 must be verified at all times in the finished products. Preferably, the profiling of the boards 2 on their narrow longitudinal sides 5 is carried out with beveled circular saw blades, e.g., with a bevel of 15 degrees for the production of both dovetail profiles and folding profiles 9 with folding profile angles SW of 15 or 75 degrees.

[0042] A layer of adhesive is then applied to the side profiles of the longitudinal narrow sides 5.

[0043] In a further process step, the pairs of boards 14 are arranged mirrored relative to each other with respect to the central transverse axis 6 and glued together in a press under the influence of exclusively surface pressure FD on the top side 7 and / or the bottom side 8 of the wood composite panel 1, 10. The resulting so-called "carpet" can be produced essentially indefinitely. Pairs of boards 14 can also be placed on top of each other in several layers with adhesive applied to their facing top and bottom surfaces and then pressed together by surface pressure. What is new compared to the prior art is that this manufacturing process can be carried out in a single step.

[0044] Preferably, the pairs of boards 14 of the wood composite panel, which are connected to one another at their longitudinal narrow sides 5, are aligned such that adjacent pairs of boards 14 are arranged in a neutral annual ring position.

[0045] The described process steps can be repeated as often as required to produce additional layers. The layers are preferably placed parallel to one another and glued together to form a wood composite panel 20 or 30. The surfaces of the formed layers can be glued together in the as-sawn state, i.e., without prior surface smoothing, if a suitable press is used, e.g., one that provides pressure compensation through oil filling.

[0046] The wood composite panel 1, 10, 20, or 30 produced as described above can be cut to length in width along at least one sawing direction, preferably substantially parallel to the longitudinal narrow sides 5. Furthermore, the cut-to-length wood composite panel 1, 10, 20, or 30 can be glued and / or galvanized to other wood composite panels along its width narrow sides 18.

[0047] The production of a wood composite panel 1, 10, 20, or 30 according to the processes described above enables previously unattainable low manufacturing costs and high yields. The production of wood composite panels 1, 10, 20, or 30 according to the invention is preferably carried out using a high-frequency press, with subsequent cutting and / or finger-jointing enabling the manufacture of a wide variety of products, for example, single- or multi-layer cross-laminated timber panels or beams for timber construction.

[0048] In Fig. 7 and Fig. 8A further embodiment of a single-layer wood composite panel 50 according to the invention is shown in cross-section. The wood composite panel 50 consists of boards 22, wherein two boards 22 are combined to form a pair of boards 24, and adjacent pairs of boards 24 are connected to one another. The term "board," as used herein, also includes "planks," which are boards with greater thicknesses. The boards 22 have profiles in the form of dovetails 13 along their longitudinal narrow sides 5, wherein the facing dovetail profiles 13 of adjacent boards 22 are complementary to one another, so that by sliding the dovetail profiles 13 into one another, two boards 22 are connected to one another to form a pair of boards 24.The boards 22 have a trapezoidal cross-section transverse to their longitudinal extent, in which the longitudinal narrow sides form the legs of the trapezoidal cross-section, wherein the boards 22 are arranged mirrored to one another with respect to a central transverse axis 6. It should be noted that the embodiment of . Fig. 7 Overlaps of the boards 22 on some of the dovetail profiles 13, but this wood composite panel 50 can also be manufactured without overlaps, as can be seen from the embodiments according to Fig. 9A and Fig. 9B is shown.

[0049] The outer longitudinal narrow sides 5 of each pair of boards 24 have at least one dovetail profile 13, wherein the dovetail profiles 13 are shaped such that the dovetail profiles 13 formed on the outer longitudinal narrow sides 5 complement each other when connecting adjacent pairs of boards 24, or in other words are formed oppositely or complementarily.

[0050] At the Fig. 7 and Fig. 8 In the illustrated embodiment of the wood composite panel 50, the dovetail profiles 13 on the longitudinal narrow sides 5 of the mutually facing boards 22 of each pair of boards can be spaced from the central transverse axis 6 by approximately 0.1 mm to 0.8 mm, preferably by approximately 0.3 mm to 0.6 mm, particularly preferably by approximately 0.4 mm to 0.5 mm, whereby an overlap occurs when the adjacent boards 22 are connected on the mutually facing longitudinal narrow sides 5. This overlap is leveled out by surface pressing of the pair of boards 24, whereby the dovetail profiles 13 wedge into each other and thus a better connection is created. The boards 22 are connected to each other in a moist, i.e. undried, state. In the Fig. 7 and Fig. 8In the illustrated embodiment of the composite wood panel 50, the external dovetail joints 13 of the pairs of boards 24 are not offset from the central transverse axis 6. This eliminates the need to use a press when joining pairs of boards 24. However, it is preferable, e.g., for load-bearing applications, to only join dry pairs of boards 24 together. This is not an embodiment of the invention and is described here for illustrative purposes only. It should be noted that in other embodiments of the wood composite panel 50 according to the invention, the outer longitudinal narrow sides 5 of the pair of boards 24 are also spaced from the central transverse axis 6 by approximately 0.1 mm to 0.8 mm, preferably by approximately 0.3 mm to 0.6 mm, particularly preferably by approximately 0.4 mm to 0.5 mm, whereby, when adjacent pairs of boards 24 are connected, an overlap is produced on the mutually facing longitudinal narrow sides 5, which is leveled out by pressing using a press.

[0051] In Fig. 8 a single-layer wood composite panel 50 according to the invention is shown, in which the connecting dovetail profiles 13 can be produced at an angle of 25° to 90° on the tree edge of side boards as well as in boards and planks made from the whole trunk, e.g. using the measurement data of the boards 22 and / or the board pairs 24. The wood composite panel can be divided, preferably in the fresh state, into standard widths (shown in dashed lines as exemplary widths A, B, C), e.g. in a 2 cm grid, whereby wood composite elements are provided in a grid of 6, 8, 10, 12, 14, 16, ... up to about 40 cm. The wood composite panel 50 is preferably divided lengthwise approximately in the middle of the width of the boards 22, which can be followed by a drying process.

[0052] It should be noted that all embodiments of the wood composite panels and the pairs of boards according to the invention can be subjected to additional processing steps depending on the intended use, in particular a calibration of their thickness to the same thickness by planing, milling and / or sanding.

[0053] In Fig. 9A A three-layer wood composite panel 60 according to the invention is shown in cross-section, which is composed of three single-layer wood composite panels 50 arranged one above the other by means of adhesive bonding. The single-layer wood composite panels 50 are similar to those of Figures 7 and 8, with the difference that none of the dovetail profiles 13 are spaced from the central transverse axis 6 and therefore have no overlap. The overlap-free wood composite panels 50 already have the required formats for the wood composite panel 60 and can be seamlessly placed and glued together without any need for a cut-off board to protrude at the edge of the wood composite panel 60. Furthermore, it should be noted that the middle wood composite panel 50 is arranged transversely (crosswise) to the outer wood composite panels 50, whereby the three-layer wood composite panel 60 forms a cross-laminated timber. Multi-layer wood composite panels 60 with five, seven, nine, etc. layers can also be manufactured as cross-laminated timber. The top side 7 of the uppermost single-layer wood composite panel 50 and the underside 8 of the lowest single-layer wood composite panel 50 represent the outer visible surfaces of the three-layer wood composite panel 60.The middle single-layer wood composite panel 50 can be cost-effectively composed of side boards, center boards, center planks, squared timber planks, cross-timber planks and / or center planks of a block-shaped substrate 3.

[0054] Fig. 9B shows a variant of the wood composite panel 60 from Fig. 9A , in which the boards of each pair are connected to each other by folding profiles 9 instead of dovetail profiles 13. The pressing of the wood composite panel 60 can be done in one step.

[0055] Fig. 10shows a cross-section of a board 2, which has been cut as a thick side board from a substrate 3, namely a freshly cut tree trunk. The tree trunk has a butt end 3a, a center 3b, and a top 3c, which is the top end. The cross-sectional view of the board 2 is taken from the center 3b of the tree trunk. The board 2 has been provided with a folding profile 9 on the left and several dovetail profiles 13 on the right at its wane edges WK (also called tree edges and representing that part of the board at the tree's circumference), with adjacent dovetail joints 13 being formed inversely to one another.In order to illustrate the excellent utilization of the tree volume by this configuration of board 2, two rectangular boards 30, 31 have been drawn in a thin line within the board, as they would be in cutting processes according to the state of the art as side boards with a wide kerf between the boards 30, 31 and a lot of sawdust next to the boards 30, 31.

[0056] Fig. 11 shows in cross-section another board 2, which has been cut as a thick side board from a substrate 3, namely a tree trunk in its fresh state. This board 2 differs from the board 2 of Fig. 10 only because several dovetail profiles 13 are milled into the forest edges on the left and right.

[0057] Fig. 12shows in cross-section another board 2, which has been cut as a thick side board from a substrate 3, namely a tree trunk in its fresh state. This board 2 corresponds to the board 2 of Fig. 11 , wherein it is demonstrated that in the case of thick tree trunks and correspondingly wide boards 2, the board 2 can be divided lengthwise by longitudinal cuts along cutting lines 2d, 2e, so that an inner board 2a with a rectangular cross-section and smooth side surfaces and two edge boards 2b, 2c are obtained, each of which has a wane as a side surface into which several dovetail profiles are milled.

[0058] Fig. 13shows a cross-section of a pair of boards 14 made up of two boards 2 which are connected to one another by two dovetail profiles 13 which are designed inversely to one another and into which a guide bevel 17 is milled on each of the outer side edges, the two guide bevels 17 being aligned parallel to one another. Furthermore, a preferred design of the dovetail connection for thinner side boards of e.g. 20, 25, 30 mm is shown, where a mechanical form fit with a frictional connection can be created by designing a wider root and particularly in the middle also at the head height. A difference in the head height can also be designed along the design length of the wedge bevel, as shown, with the connection on the pair of boards being shown by a folding profile to the panel. A further advantage of the inverted design of dovetail profiles according to the invention is that breaking off orChipping of dovetail parts in the groove at the more pointed dovetail corner can be avoided.

[0059] Fig. 14shows a front view of a tree trunk seen from the top side, from which it can be seen that according to the invention several side boards S1, S2, S3, S4 and side boards S1', S2`, S3', S4` opposite these in relation to the central axis M of the tree trunk in the same position are cut off. The longitudinal cut of the side boards S1, S2, S3, S4, S1', S2`, S3', S4` is parallel to the shell, so that each side board has a constant thickness. After all side boards have been cut off, a center plank Z remains with a thickness that increases over its length. The opposite side boards S1 and S1', S2 and S2`, S3 and S3', S4 and S4` form joining partners, which are joined together to form pairs of boards after profiles have been formed on their wane edges WK.This illustration shows that the wane edges WK, which form the side surfaces of the side boards, are positioned at different, sometimes very acute angles to the base and top surfaces of the side boards. This means that on the outer side boards S4, S4', the top surfaces are less conical, almost parallel, and also have a similar wane edge at the top (pointed) and butt (steep), thus enabling maximum yield to be achieved. Wanking, or conical taper, of a tree refers to the reduction in the diameter of a trunk towards the treetop. The top surfaces of the other boards S3, S2, and S1 are also less conical than in the state of the art. This reduces the production of cheaper sawmill by-products (chips and wood chips for the paper and wood-based materials industries) by at least a third.In prior art processing, such side boards were considered inferior due to their sloping sides. However, according to the invention, they represent a high-quality wood raw material for the production of paired boards and wood composite panels.

[0060] Fig. 15shows a cutting pattern through a substrate 3 in the form of a fresh tree trunk, e.g. with a diameter of at least 40 cm at the top, wherein the cutting pattern is shown from the outside up to the center plank Z of the tree trunk, but the lower half of the cutting pattern, not shown, is symmetrical to the upper half of the cutting pattern. In the drawing - seen from top to bottom - a thick side board 2 has first been cut off, the outer side (wavy edge side) of which are profiled on one side with several identical dovetail profiles 13, preferably while the cut board 2 is still fresh, and on the other side with a folding profile 9.The drawing shows how this board 2 is joined to a board 2' cut off in the same position from the opposite side of the central axis M of the tree trunk and also provided with dovetail profiles 13 and a folding profile 9 to form a pair of boards 14 by inserting the two boards 2 into each other lengthwise with their dovetail profiles 13. It can be seen in this illustration that the two boards 2 have been arranged in a neutral annual ring position according to craft rules, i.e. that the curvature lines of the annual rings of the two boards 2 run opposite one another. This uppermost cut-off side board 2 corresponds to the one in . Fig. 10 shown side board 2. Following this first side board 2, a second side board 2 is cut off, which is profiled on both sides of the forest edge with dovetail profiles 13. This side board 2 corresponds to that of Fig. 11. Since this side board 2 is already very wide, it is split twice lengthwise, so that narrower side boards 2b, 2c and a middle board (plank made of heartwood) 2a are obtained. Fig. 15 also shows how the outer side board 2c can be joined with a board 2b' cut in the same position from the opposite side of the central axis M of the tree trunk and also provided with dovetail profiles 13 in a neutral annual ring position from board 2c with board 2b to form a pair of boards 14 containing predominantly sapwood 2b'. A third board 2, closer to the center, is already so wide that it can be divided into a total of five boards, with three planks or battens as center boards. Finally, a center plank Z is cut out of the substrate 3, which contains the wedge-shaped heartwood in the central axis M. This center plank Z is divided, for example, into a total of nine trapezoidal boards Z1, Z2, Z3, Z4, Z1', Z2', Z3', Z4', whereby in Fig. 15It is also shown how two squared timbers Z1 and Z1', Z2 and Z2', Z3 and Z3', Z4 and Z4', which are opposite each other in the same position in the center plank Z, can be joined together again in parallel to form pairs of boards by forming dovetail profiles 13 in the radial annual ring and inserting them into each other along the dovetail profiles 13 in a neutral annual ring position, whereby in addition to the form fit by the dovetail profiles 13, gluing can also be carried out. In this way, the tree trunk is utilized with the least possible amount of sawmill waste, and high-quality parallel pairs of boards and squared timber are produced from it, and only parallel connected pairs of boards leave the saw, which can be further processed and finished as described above. If, for example, one starts from the wide boards / planks (e.g. as 2a / 2b / 2c in Fig. 15) the boards 2b and 2c are joined together in the fresh state by dovetail profiling 13, one obtains pairs of boards 14 already in the finished shape and dimension.

[0061] Fig. 16A to 16F show the production of pairs of boards and the resulting composite wood panels from thin tree trunks, so-called weak wood, in a schematic representation. First, the thin tree trunk is split lengthwise into two halves, which form the two - almost semicircular - boards 2, 2. A core wedge, such as in the embodiment of Fig. 15 is not formed during dividing. On the opposite sides of the boards 2, 2, guide bevels 17 are formed along the length of the boards 2, 2. This condition is in Fig. 16A Then, dovetail profiles 13 are formed in both boards 2, 2 along the length of the boards 2, 2, see Fig. 16B . In the following processing step, shown in Fig. 16C, the left board 2 is turned around its transverse axis and then rotated lengthwise 90° clockwise. The right board 2 is not turned, but is also rotated lengthwise 90° clockwise. This means that the dovetail profiles 13 of the two boards 2, 2 face each other. In the next step, shown in Fig. 16D , the two boards 2, 2 are pushed together lengthwise at the dovetail joints 13, whereby the two connected boards 2, 2 form the board pair 14. The joining can, but does not have to, be done with the aid of glue. Pressure application after pushing them together is not necessary. In the next step, shown in Fig. 16E, additional dovetail profiles 13 are formed on the sloping longitudinal sides of the pair of boards 14. With the help of these dovetail profiles 13 on the sloping longitudinal sides, the pair of boards 14 can be joined lengthwise with other similar pairs of boards 14 to form a wood composite panel 1 of any width by sliding the pairs of boards 14 into each other at the dovetail profiles, optionally with the aid of adhesive. Pressure can be applied after joining, but is not necessary. The wood composite panel 1 produced in this way is in Fig. 16F It can be seen that both the boards 2 of each pair of boards 14 and the adjacent pairs of boards 14 are arranged in a neutral annual ring position.

[0062] Fig. 17A to 17Fshow the production of pairs of boards and the resulting composite wood panels from thin tree trunks, so-called weak wood, in a schematic representation. The steps of the production process according to Fig. 17A to 17D correspond to those of Fig. 16A to 16D For explanation, please refer to the above description of Fig. 16A to 16D In the next step, shown in Fig. 17E , folding profiles 9 are formed on the sloping longitudinal sides of the pair of boards 14 instead of dovetail profiles. With the help of these folding profiles 9 on the sloping longitudinal sides, the pair of boards 14 can be joined lengthwise with other similar pairs of boards 14 to form a wood composite panel 1 of any width by hooking the pairs of boards 14 into each other at the folding profiles, optionally with the aid of adhesive, and then applying surface pressure. The wood composite panel 1 produced in this way is in Fig. 17FIt can be seen that both the boards 2 of each pair of boards 14 and the adjacent pairs of boards 14 of the composite wood panel 1 are arranged in a neutral annual ring position. The boards 2 and pairs of boards 14 are joined together while the wood is still fresh.

[0063] In the Figures 18A to 18E is the production of a pair of boards according to Fig. 13 First, two boards 2 are cut from a tree trunk as side boards by cutting parallel to the shell, whereby the boards are cut at corresponding, opposite layers of the tree trunk with respect to a longitudinal axis of the tree trunk, see Fig. 18E . Guide bevels 17 are formed on the side surfaces of the boards 2, see Fig. 18A Then a dovetail profile 13 is milled on one side surface of each board 2, see Fig. 18BNext, a board 2 (in the drawing, the left board 2) is rotated 180° around its longitudinal axis. The two boards 2, 2 are thus in opposite, i.e. neutral, annual ring positions and with their dovetail profiles facing each other, see Fig. 18C Now the two boards 2, 2 are pushed together lengthwise at their dovetail profiles 13 while still fresh, ie moist, and thus form the pair of boards, as shown in Fig. 18D shown.

Claims

1. A pair of boards (14) consisting of two boards (2) joined together along their longitudinal narrow sides (5) profiled in the longitudinal direction (4), the profiling being a profiling already carried out in the sawmill in the fresh state of the boards (2), characterized in that the boards (2) originate from the same tree trunk, preferably from the same tree trunk cut to a standard raw wood length, with substantially the same moisture content and conicity and are cut from layers of the tree trunk corresponding to one another, opposite layers of the tree trunk in relation to a longitudinal axis of the tree trunk, wherein a guide chamfer (17) is formed on the boards (2) to be joined, wherein the two boards (2) have been joined in the fresh state of the boards (2) and wherein the two boards (2) are arranged in a neutral growth ring position in relation to one another, wherein preferably the pair of boards is provided with guide chamfers (17) parallel to one another on its two narrow longitudinal sides.

2. The pair of boards (14) according to claim 1, characterized in that the profiling of the boards (2) at the common longitudinal joint is formed as mutually complementary dovetail profiles (13) or hinged profiles (9) having a hinged profile angle SW equal to or smaller than 90 angle degrees, the longitudinal joint optionally being provided with an adhesive, and preferably, when a plurality of dovetail profiles (13) are formed on each board, adjacent dovetail joints (13), for example for in each case e.g. approx. 10 mm of the board thickness, being formed inversely to one another, the dovetail profiles (13) preferably being milled in the rounding of the beam edge.

3. The pair of boards (14) according to any one of the preceding claims, characterized in that the geometry of the dovetails in the tangential wood of the annual rings in the round tree edge at the root of the tails, preferably in a minimum width of 6 mm, is designed with higher strength for greater loading by transverse forces, wherein the central dovetails are approximately twice as high as the laterally outer dovetails in the rounding of the tree edge, wherein preferably dovetails in the standing wood of the radial annual rings in the trapezoidal central plank, e.g. the trapezoidal planks (Z with Z'), are about 3 mm wide and about 2 mm high at the root.

4. The pair of boards (14) according to any one of the preceding claims, characterized in that the width of each board (2) at its narrow end at least grazed by the saw is at least 30 mm, preferably at least 40 mm, the board width preferably being selectable as large as possible, e.g. in 1 mm increments.

5. The pair of boards (14) according to any one of claims 2 to 4, characterized in that the boards (2) are profiled with dovetail profiles (13) without overlap in relation to one another and are joined together to form a pair of boards (14) by sliding the boards (2) into one another at their dovetail profiles (13) without pressing pressure, dovetail profiles (13) preferably being formed on the longitudinal narrow sides (5) of the pair of boards for joining pairs of boards (14).

6. The pair of boards (14) according to any one of claims 2 to 4, characterized in that the boards (2) are profiled with dovetail profiles (13) without overlap in relation to one another and are joined together to form a pair of boards (14) by sliding the boards (2) into one another at their dovetail profiles (13) without pressing pressure, wherein hinged profiles (9) are formed on the longitudinal narrow sides (5) of the pair of boards (14), which are preferably dimensioned such that when dry pairs of boards (14) are joined together by means of the hinged profiles (9), an overlap (12) of preferably 0.3 to 0.6 mm in height results and this overlap (12) shrinks when pressing pressure is applied.

7. The pair of boards (14) according to any one of the preceding claims, characterized in that the boards (2) of the pair of boards (14) are formed by longitudinally bisecting a round timber without a core wedge or core plank in the fresh state as the two halves of the split round timber and are connected to one another in parallel by means of dovetail profiles (13) in a neutral annual ring position.

8. The pair of boards (14) according to any one of the preceding claims, characterized in that the width of the boards (2; 2a, 2b, 2c) joined together to form the pair of boards (14) is selected such that the pair of boards (14) has a finished shape and dimension.

9. The pair of boards (14) according to any one of the preceding claims, characterized in that respectively two boards (Z1, Z1'; Z2, Z2'; Z3, Z3'; Z4, Z4) lying opposite each other in the same position in the central plank (Z) and formed as squared timbers (Z1, Z1'; Z2, Z2'; Z3, Z3'; Z4, Z4) are connected with dovetail profiles (13) in the radial annual ring parallel to the pair of boards (14).

10. A wood composite panel (10) comprising pairs of boards (14) connected to one another at their longitudinal narrow sides (5) according to any one of the preceding claims, wherein adjacent pairs of boards (14) are arranged in a neutral annual ring position.

11. The wood composite panel (20, 30) according to claim 10, comprising at least two superimposed layers of pairs of boards (14), characterized in that the pairs of boards (14) of a respective layer are provided with adhesive at their profiles and adhesive is applied to the surfaces of adjacent layers of pairs of boards (14), the pairs of boards (14) of a respective layer being arranged parallel to one another.

12. The wood composite panel (60) according to claim 10, comprising at least three superimposed layers of pairs of boards (14), characterized in that the pairs of boards (14) of a respective layer are provided with adhesive at their profiles and adhesive is applied to the surfaces of adjacent layers of pairs of boards (14), the pairs of boards (14) of adjacent layers being arranged crosswise to one another.

13. A method for producing a pair of boards (14), in particular a pair of boards according to any one of claims 1 to 9, characterized by the cutting of two boards (2) from the same tree trunk, preferably from the same tree trunk cut to a standard raw wood length, in the fresh state of the tree trunk from layers of the tree trunk which correspond to one another and lie opposite one another with respect to a longitudinal axis of the tree trunk, forming profiles on at least one of the longitudinal narrow sides (5) of the boards (14) in the fresh state of the boards, arranging the two boards (2) so that the boards (2) lie mirrored to one another with respect to a central transverse axis (6), and joining the boards of the longitudinal narrow sides (5) by pushing them into one another along their profiles in the fresh state of the boards (2), optionally with prior application of adhesive, in particular PU adhesive, to the profiles.

14. The method for producing a pair of boards (14) according to claim 13, characterized in that the profiling of the boards (2) at the common longitudinal joint is formed as mutually complementary dovetail profiles (13) or hinged profiles (9) having a hinged profile angle SW equal to or smaller than 90 angle degrees, adjacent dovetail joints preferably being formed inversely to one another when forming a plurality of dovetail profiles (13) on each board (2), wherein preferably the boards (2) are profiled without overlap in relation to one another and the guide chamfers (17) are formed as stops for the formation of dovetail profiles (13) for connecting pairs of boards (14) at their longitudinal joints by means of the dovetail profiles (13).

15. A method for producing composite wood panels from pairs of boards (14) produced by the method according to one of claims 13 or 14, characterized by: flattening the pairs of boards, forming complementary inclined profiles with hinged profiles (9) of opposite shape on the facing longitudinal narrow sides of the pairs of boards (14), arranging the pairs of boards next to each other (14), applying adhesive to the longitudinal narrow sides of the pairs of boards (14), joining adjacent pairs of boards (14) on their longitudinal narrow sides, optionally with simultaneous hooking of the hinged profiles (9), and pressing the pairs of boards joined together (14).

16. The method for producing wood composite panels (20, 30) according to claim 15, characterized in that the wood composite panels are constructed in at least two layers by arranging the pairs of boards (14) in at least two superimposed layers and joining them together, the pairs of boards of each layer being arranged parallel to one another and the adjacent layers being glued together over their entire surface in the same working step.

17. The method for producing wood composite panels (20, 30) according to claim 16, characterized in that a plurality of multilayer wood composite panels are joined together in panel width or in predefined required widths or system widths by means of fingerjointing, the wood composite panels being layered in at least two layers, the boards first being sorted in raw wood length without end knots or knotted parts of the boards being cut to produce the pairs of boards, and the multilayer wood composite panels being cut into glued squared timbers.