Built-up wooden sectional beam for the erection of loadbearing walls, and walls erected with such sectional beams

Abstract

 A built-up sectional beam for the erection of load-bearing or non-load bearing walls, more particularly load-bearing inside walls and inside cavity walls, characterized by its construction comprising a core (1) made from wood, the direction of the grain of which extends perpendicularly to the longitudinal axis (4) of the sectional beam and in the plane (5) of the wall (6) to be erected therefrom, with a finishing layer (2) on one or both sides, more particularly a wooden or plastic strip. Walls erected with such sectional beam.

Description

[0001] This invention relates to built-up wooden sectional beams for erecting load-bearing or non-load bearing walls.

[0002] The invention also relates to the walls, more particularly load-bearing inside cavity walls and load-bearing inside walls, erected with such wooden sectional beams.

[0003] Wood is a material frequently used for making walls. It is used for erecting non-load bearing inside walls in buildings; garden sheds; saunas, and lightweight and possibly dismantlable cottages. It is less used for the erection of the load-bearing inside cavity wall of a cavity wall or a load-bearing inside wall.

[0004] One known technique to make wood suitable for this purpose is to stack tongued and grooved wooden beams on one another with special provision for the corner connections, inter alia as indicated in the Belgian patent number 871 546, so that the beams inter-engage rigidly on the line where they respectively meet horizontally and vertically, thus allowing a solid construction. In consideration of their special section, the known construction of such beams is the one in which the direction of the wood grain is parallel to the longitudinal axis of the sectional beam. It is in other words the conventional construction of solid, i.e. not built-up, beams and the like.

[0005] Although that construction is satisfactory for the intended use, the built-up sectional beam according to the invention provides a number of advantages. The built-up sectional beam according to the invention in any case solves one problem which accompanies the conventional above beam structure as used for the intended use, i.e. the problem of the expansion of the wood depending upon its degree of moisture. Let us assume that the degree of moisture of the wood during processing thereof to sectional beams in the factory has a moisture content of 8%. If the sectional beam is processed at the site of the construction, this moisture content rises to 12 - 15% in view of the circumstances in which the beams are erected. Once the building is finished, or if the wooden walls erected with such sectional beams are again in a dry atmosphere, the moisture conten.t will develop to a state of equilibrium which is about 8% for an inside wall and about 12% for an inside cavity wall. During this development of the wood moisture content, from the time that the wood reaches the site until the time that the wood moisture content reaches its state of equilibrium, the beams will expand and contract, and in the case of a wall of a certain area this will very rapidly result in a few centimeters change in the dimensions.

[0006] The object of the invention is therefore to provide sectional beams which solve this problem and which provide a more practical sectional beam for the purpose in view.

[0007] The wooden sectional beam according to the invention is characterized by its construction consisting of a core, the direction of the grain of which is perpendicular to the longitudinal axis of the sectional beam and lies within the plane of the wall to be erected therewith, having a finishing layer, more particularly a wooden or plastic strip, on one or both sides.

[0008] In order better to explain the construction and advantages of a wooden sectional beam according to the invention, one embodiment of a wooden sectional beam according to the invention will be described in detail hereinafter as an example without any limiting force with reference to the accompanying drawing wherein :

Fig. 1 is a perspective of a wooden sectional beam according to the invention, in which the finishing layer is a wooden strip.

Fig. 2 is a section of a number of wooden sectional beams according to the invention disposed one upon the other.

[0009] The wooden sectional beam according to the invention can be sub-divided into two main parts : the core 1 and the surface layers 2 (Fig. 1).

[0010] The core 1 in turn consists of contiguous glued-together blocks 3, the direction of the grain of which extends perpendicularly to the longitudinal axis 4 of the beam and in the plane 5 of the wall 6 for erection (Figs. 1 and 2). The core 1 has to take and transmit the weight of, and vertical loads on, the structural elements situated thereabove. In other words, the core 1 takes the compression forces situated in the plane 5 of the wall 6.

[0011] Core 1 has a surface layer 2 on each side, which in this case is in the form of a wooden strip, the direction of the grain of which is parallel to the longitudinal axis 4 of the beam. The surface layer 2 is glued against the glued-together blocks 3 so that the resulting beam forms a rigid unit. The still rectangular beam formed in this way (dotted line in Fig. 1) is then further processed to give the required section (solid line in Fig. 1). In a preferred embodiment, the sectional beam according to the invention is provided with a tongue 7 at the top and with a groove 9 corresponding to the tongue 7 at the bottom.

[0012] The surface layer 2 has a double function : on the one hand it provides a finish for the beam and thus has an aesthetic function, while on the other hand it takes any bending loads on the wall 6. Bending stresses of this kind occur if the wall 6 is formed with openings, e.g. window and door openings, or if the wall 6 is subjected to compressive loading perpendicularly to its plane 5. Since the core 1 is constructed from contiguous glued-together blocks 3 the core 1 will be able to offer resistance only to insignificant bending stresses. In the surface layer 2, on the other hand, the bending stress is taken by the wood grain.

[0013] If the wooden sectional beam according to the invention is compared with the conventional beam structure, both used for constructing load-bearing or non-load bearing walls, it will be seen that the beam according to the invention is much less subject to dimensional changes in response to varying dampness. This can readily be explained : the tangential expansion of wood, or the expansion in the direction of the grain, is less than the radial expansion of wood, or the expansion perpendicular to the direction of the grain. The crossing of the grain directions and the rigid connection of the core 1 and the surface layer 2 causes this difference in expansion of the two parts of the beam to counteract the expansion of the resulting wall in the two directions or restricts the expansion in the two directions of the beam. Since the direction of the grain of the surface layer 2 is horizontal, the surface layer will expand mostly across it vertical dimension, while the core will expand mostly across its horizontal dimension since its grain direction is vertical. The rigid connection of the two parts causes the expansions across the two directions of the wall to be restricted to the minimum expansion of the wood, i.e. the tangential expansion. Consequently, the beam can have larger dimensions so that larger free wall surfaces are possible.

[0014] The beam structure according to the invention is also much more favourable as regards strength. The compressive strength of wood is much higher in its tangential direction than in its radial direction. The core 1 of the beam according to the invention can thus be narrower than a conventional beam to be able to take the same compressive load. The surface layers 2 take the bending load perpendicularly to the plane 5 of the wall just as well as a conventional beam in view of their distance from the beam neutral line. In other words the wood is used to much better advantage.

[0015] The beam structure according to the invention also enables the core 1 to be made from a less expensive type of wood than that of the surface layers 2 in view of the aesthetic requirements of the latter. To obtain a good outer surface a conventional beam must be completely made from the more expensive type of wood.

[0016] Of course the surface layer 2 can also be made from a plastic or a plaster product, depending upon the aesthetic or practical requirements or loading of the beam.

[0017] If required, the top of the tongue 7 of the sectional beam according to the invention may have a joint filler strip 8 stuck thereto (Fig. 2). When the sectional members are then placed one upon the other the strip 8 occupies a position between the tongue 7 and the groove 9 of two consecutive beams. This strip 8 is advantageous in order to seal off any heat and noise gaps in the erected wall.

Claims

1. A built-up sectional beam for the erection of load-bearing or non-load bearing walls, more paricularly load-bearing inside walls and inside cavity walls, characterized by its construction comprising a core (1) made from wood, the direction of the grain of which extends perpendicularly to the longitudinal axis (4) of the sectional beam and in the plane (5) of the wall (6) to be erected therefrom, with a surface layer (2) on one or both sides.

2. A built-up sectional beam according to claim 1, characterized in that the core (1) consists of contiguously secured wooden blocks (3), the direction of the grain of which is perpendicular to the longitudinal axis (4) of the sectional beam and lies in the plane (5) of the wall (6) to be erected therewith.

3. A built-up sectional beam according to claim 2, characterized in that the wooden blocks (3) are glued together.

4. A built-up sectional beam according to claim 1, characterized in that the surface layer (2) is a wooden strip secured to the core (1), the direction of the grain of the strip extending perallel to the longitudinal axis (4) of the sectional beam.

5. A built-up sectional beam according to claim 4, characterized in that the wooden strip is glued to the core (1).

6. A built-up sectional beam according to claim 1, characterized in that the surface layer (2) is a plastic or plaster strip.

7. A built-up sectional beam according to any one of claims 1 to 6 characterized in that the sectional beam is provided with a tongue (7) at its top or bottom and with a groove (9), corresponding with the tongue (7) respectively at its bottom or top.

8. A built-up sectional beam according to claim 7, characterized in that a joint filler strip (8) is provided on the tongue (7).

9. A built-up sectional beam according to claim 7, characterized in that a joint filler strip (8) is disposed in the groove (9).

10. A constructional element, more particularly load-bearing or non-load bearing walls, ceiling finishes, floor finishes, pre-assembled panels, more particularly load-bearing inside walls and inside cavity walls, constructed with built-up sectional beams according to claims 1, 2, 3, 4, 5, 6, 7, 8 and/or 9.

Drawing