| 摘要 |
In the multilayer beam, the major part of the volume is formed by a central layer comprising fragments of vegetable matter which has been extruded, mixed with binders and consists of natural materials, such as wood, straw or the like. The central layer is adhesively bonded to an outer layer. The central layer comprises a mixture of coarse and fine pin-shaped chips having a density of from 450 to 750 kg/m<3>, the orientation of the chips or fibres extending essentially in the longitudinal direction of the beam. Furthermore, the outer layers (2) comprise natural-wood boards which have just been sawn or are planed. The ratio of the thickness of said boards to the thickness, extending in the same direction, of the central layer is between 1:6 and 1:25. The central layer is rectangular in cross-section and has a cavity which passes through it and is in the form of a slot in cross-section. <IMAGE>
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