| 摘要 |
A beam with an upper edge 1 and a lower edge 2 of wood or wood material (for example, laminate) with good strength properties and an intermediate part 3 glued between these edges and made of a material with lesser strength which in addition, in order to reduce weight and volume, has been equipped with cavities in the form of a number of holes 4, 5, 6 which run longitudinally and transversely in the beam. <IMAGE> |
