The present invention allows a greatly improved utilisation of the wooden material or timber available.

Thus, the present invention provides an elongated wall cladding board made from solid wood and comprising at least two layers of natural wood bonded together and defining a front and a back surface of the cladding board, respectively, said wooden layers being of different quality and having the fibres thereof extending in substantially the same direction. Thus, visually a wall cladding board according to the invention appears as if it was made from a single piece of wood in a traditional manner. However, from a specified amount of basic wood of varying quality it is possible to produce more than the double amount of solid boards according to the invention of good, aesthetic quality than possible when using the conventional methods. Said at least two layers of wood may be of the same type or of different types of wood. In this context the term "same type of wood"does not necessarily mean identical species of wood, but should also comprise similar types of wood as far as structure and hardness are concerned. As an example, different sorts of conifer or different kinds of hardwood are considered to be"same type of wood".

However, the said at least two layers of natural wood need not necessarily be of the"same type of wood"if the aesthetic quality and/or the density and/or the strength characteristics of the bonded wooden layers are different. As an example, the wooden layer defining the front surface of the board may be made from cedar and the layer defining the back surface may be Douglas fir.

Any of the wooden layers may be divided into two or more lengths the ends of which are arranged in abutting engagement. In the preferred embodiment,

however, at least the layer defining the front surface of the cladding board is a unitary, undivided layer of natural wood.

The thickness of the bonded layers may be substantially the same, or the wooden layer being of the best aesthetic quality may be substantially thinner than the other wooden layer defining the back surface. In the presently preferred embodiment one of the wooden layers-preferably the one defining the front surface of the board-has a tapered cross-sectional shape. Such wall cladding boards are adapted to be arranged in clinker fashion.

The side surface defining the front surface of the board may be planed or finished in any other way depending on the appearance of the wall cladding desired. In the presently preferred embodiment the front surface of the cladding board is a saw cut surface.

Like traditional wall cladding boards the boards according to the invention preferably has a rectangular shape with random lengths typically within the range of 180-600 cm, a width within the range of 10-25 cm, and a thickness within the range of 15-25 mm. Each cladding board according to the invention may further comprise a tongue and a groove extending along opposite, substantially parallel edges of the board, so that the boards may be mounted in a traditional manner.

When the board is formed with a tapered cross-sectional shape as described above a rabbet may be formed along the thicker edge of the board adapted to receive the thinner edge of a corresponding board.

The present invention further provides a method of making an elongated wall cladding board from solid wood, said method comprising bonding at least two layers of natural wood together and defining a front and a back surface of the cladding board by said at least two layers, respectively, said wooden layers being chosen so as to be different in quality and being arranged so that the fibres thereof extend in substantially the same direction. The wooden layers may be bonded together in any suitable manner, such as nails, screws, staples or other mechanical connecting means. Preferably, however, the wooden layers are bonded together by means of a suitable glue or an adhesive.

In a preferred embodiment three layers of wood are sandwiched and bonded together, the intermediate layer subsequently being cut into two sub-layers so as to form a pair of boards. The front surface of each board thus produced may be defined either by the sub-layers or by the outer layers.

The thickness of the bonded layers may be substantially the same. In the preferred embodiment, however, the intermediate layer is cut along a plane defining an acute angle with the opposite side surfaces of the intermediate layer so as to divide the intermediate layer into a pair of sub-layers each having a tapered cross-sectional shape.

Each of the opposite outer layers of said three layers is preferably more narrow than the intermediate layer, said layers being arranged so as to form a pair of exposed side surface portions of the intermediate layer, said pair of exposed side surface portions being located at opposite edges and at opposite sides of the board. Thereby a rabbet may be formed at one edge of each of said pair of boards, which are produced when the intermediate layer is being split.

The invention will now be further described with reference to the drawings, wherein Fig. 1 is an end view of a first blank for making wall cladding boards according to the invention, Figs. 2 and 3 are end views illustrating two different ways of making a first embodiment of the board according to the invention from a blank as that shown in Fig. 1, Fig. 4 is an end view of a second blank for making wall cladding boards according to the invention, Fig. 5 is an end view illustrating how a third embodiment of the board according to the invention may be made from the blank shown in Fig. 4, and Figs. 6 and 7 are end views showing wall claddings made from the boards of the types shown in Fig. 5 and in Figs. 2 and 3, respectively.

Fig. 1 shows a board blank 10 formed by bonding an intermediate layer 11 of solid natural wood of a first type or quality and two outer layers 12 of solid natural wood of a second type or quality together by means of a suitable glue or adhesive. Each of the layers 11 and 12 is preferably a unitary and undivided peace of wood.

The blank 10 shown in Fig. 1 may be used for making a pair cladding boards 13.

In Fig. 2 the intermediate layer 11 is made from a type or quality of wood intended for forming the outer side surfaces or front surfaces of the cladding boards 13, for example cedar wood, and the outer layers 12 may be made from wood of an inferior aesthetic quality or of different strength or density, for

example Douglas fir. The opposite longitudinal edges surfaces 14 of the blank 10 are machined so as to form a pair of spaced tongues 15 in one of said edge surfaces and a pair of corresponding grooves 16 in the opposite edge surface 14.

In Fig. 2 a channel 17 with a V-shaped cross-section is formed between the tongues 15 as well as between the grooves 16. The machined blank may now be split or separated into two cladding boards 13 by a cut 18 extending along a central plane between the vertices of the V-shaped channels. Preferably, the cut is a saw cut, and the surfaces formed by the cut form the outer or front surfaces of the boards being visible, when the boards are mounted so as to form a wall cladding as shown in Fig. 7. It is noticed that the side surfaces of the V-shaped channels 17 of the blank define bevelled edges on the boards 13 formed by cutting the machined blank shown in Fig. 2.

In Fig. 3 the blank 10 shown in Fig. 1 has been machined in a similar manner as shown in Fig. 2. However in Fig. 3 the V-shaped channel or groove 17 has been replaced by outer bevelled edge 19. Furthermore, in Fig. 3 the intermediate layer 11 is made from a type or quality of wood intended to form the back side of the finished cladding boards 13, while the outer layers 12 are formed by a type or quality of wood intended to form the outer side surfaces of the boards 13 being visible in use. The outer side surfaces of the blank 10 may, for example be planed in the embodiment shown in Fig. 3, when a planed outer or front side surface of the finished cladding board 13 is desired.

Fig. 4 shows a second embodiment 20 of a cladding board blank for making cladding boards according to the invention. In Fig. 4 the outer layers 12 are more narrow than the intermediate layer 11, which is made from the type of wood intended to define the outer or front side surfaces of the finished boards.

The more narrow outer wooden layers 12 are positioned in relation to the intermediate layer 11 so as to form a pair of rabbets 21 positioned at opposite edges and at opposite sides of the blank 20. Fig. 5 illustrates how the blank 20 may be divided into a pair of cladding boards 22 by means of a cut 23, such as a saw cut, dividing the intermediate wooden layer into two sub-layers. As shown in Fig. 5 the cut 23 may define a small acute angle with the parallel opposite side surfaces of the intermediate layer 11 and of the outer layers 12. It should be understood that the blank shown in Fig. 4 could alternatively be obtained by cutting or machining the rabbets 21 in the blank of Fig. 1.

Fig. 6 shows how wall cladding boards made as illustrated in Figs. 4 and 5 may be mounted so as to form a wall cladding. Because of the rabbets 21 the horizontally extending boards 22 may be lap-jointed or arranged in clinker fashion as shown. Fig. 7 shows how wall cladding boards made as illustrated in

Figs. 2 or 3 may be used to form a wall cladding. In Fig. 7 the horizontally extending boards are interconnected by means of the tongues 15 and grooves 16.

In Fig. 6 the visible front surface 24 is defined by the saw cut 23 through the intermediate layer 11, and the hidden back surface 25 is defined by the outer side surface of an outer layer 12. In Fig. 7 the front surface 24 may be either the outer surface of an outer layer or defined by the saw cut 18 depending on whether the boards 13 have been made as illustrated in Fig. 3 or in Fig. 2.