EP3741921B1 - Wood plate element made from a plurality of planks - Google Patents

Description

The present invention relates to a wooden panel element made at least largely of wood and its use.

Wood is one of the traditional and particularly widespread building construction materials. It is experiencing a renaissance in new buildings too, with regard to the CO ₂ issue, the avoidance of unusable waste, with regard to its good insulation properties and good load-bearing capacity with low weight and, above all, due to construction-biological aspects. In addition to the traditional forms of construction, such as the block house construction, this also applies to prefabricated houses and new constructions from, to a certain extent, prefabricated larger wooden panel elements for building walls or building ceilings.

Regarding the state of the art, reference can be made to our own European application 05 020 614.3 and also to the later 08 019 598.5. In both applications, pieces of wood or, in the diction of the present application, wooden planks are preferably joined together by burr strips to form wall elements, dispensing with additional connecting elements such as screws, dowels or the like. The wooden planks lie parallel in at least two layers and the ridge strips not only connect the wooden planks within the layers, but also the two layers with one another. The ridge strips have dovetail profiles, in any case cross-sectional profiles with undercuts to connect the two layers, and can, for example, be inserted into grooves of the planks when the ridge strips are very dry and clamped to the final moisture level by subsequent swelling. The applications cited, particularly the earlier ones, are helpful in understanding the following description.

For the state of the art, reference is made to CH 692 391 A5 with a plate-shaped wall, floor or roof element made of four board layers nailed or dowelled together, with the longitudinal direction of the boards in one of the layers being perpendicular to the other layers.

Reference is also made to the BE 466 087 A with a similar state of the art, but with a bitumen cardboard layer inserted between two of a total of three board layers.

Furthermore, the DE 23 40 101 A a building board for prefabricated wooden houses made of a single layer of wooden planks with transverse wedges.

Finally shows the FR 2 337 018 A also a building board made of wood, namely from a single layer of parallel wooden planks, which are connected on both flat sides by transversely but slightly sloping strips embedded in grooves.

The present invention is based on the object of proposing further improvements to wooden panel elements.

For this purpose, the invention is directed to a wooden panel element according to claim 1.

As in the cited prior art, wood panel elements are concerned with a multiplicity of elongated wooden planks, the wood fiber direction running essentially parallel to the longitudinal direction. The wooden planks are arranged parallel to one another in at least two layers, which correspond to a main plane of the wooden panel element, so that the longitudinal direction is parallel to the main plane. Cross-connecting means are also provided to connect adjacent wooden planks to one another in the layers.

These cross-connecting means can in particular be ridges in the sense of the cited applications, i.e. elongated strips (preferably made of wood) which encompass more than two adjacent wooden planks and which engage positively in corresponding grooves in the wooden planks with an undercut profile (transverse to their longitudinal direction). For example, it can be a dovetail profile if the ridge strips are in the interface between adjacent wooden plank layers, or a trapezoidal profile if the ridge strips, for example, only connect wooden planks of one layer and should be flush with the corresponding surface of the layer. The exemplary embodiments illustrate this. The cross-connection means can, however, for example also be threaded rods penetrating the wooden planks of a respective layer, in particular wooden threaded rods. Furthermore, the invention is not restricted to the material wood with regard to the cross-connecting means, although this is preferred.

As far as explained so far, depending on the individual embodiment, the wooden panel elements have different advantageous properties and can in particular be efficiently produced and, if desired, for the construction of z. B. building parts are used. However, the invention sees further potential for improvement with regard to the deformation stiffness of the wood panel elements.

It has been found that the previously known wooden panel elements show a high level of stability, particularly with regard to their load-bearing capacity, but a higher rigidity would be desirable for certain applications. This relates in particular to a resistance to displacement in the main plane of the wood panel element, so z. B. the case that the bottom of a vertically installed wooden panel element is held and the top of the wooden panel element is moved in a horizontal direction parallel to the (vertical) main plane. More generally speaking, it is primarily a matter of the rigidity with regard to the displacement or also rotation of opposite sides of the wooden panel element in mutually opposite directions, each of which lies in the main plane.

It is not absolutely necessary that the wooden panel element is completely flat and straight. At z. B. a slight curvature, the statements relate to a main plane forming a mean value. However, flat wooden panel elements are the preferred application.

According to the invention, additional stiffening elements are accordingly used between adjacent planks, which engage in grooves in the wooden planks. These stiffening elements are preferred during manufacture in the Grooves are inserted and are therefore received in a corresponding direction, that is to say in a direction perpendicular to the main plane, in the respective groove without interlocking.

This preferably means an undercut-free design of the corresponding profile of both the groove and the stiffening element. This freedom from undercuts preferably also applies to a further direction, namely parallel to the main plane. If then in this direction the groove z. B. something goes beyond the corresponding length of the respective stiffening element or is designed continuously at all, the stiffening elements can also be moved individually into the grooves and z. B. can be adjusted in their position.

Such stiffening elements are preferably provided between adjacent wooden planks of a respective layer, that is to say connect these adjacent wooden planks to one another. Then they make it more difficult for the wooden planks to move relative to one another along the longitudinal direction of the wooden planks, or they block this movement entirely. In this way, the rigidity described can be improved. The exemplary embodiments illustrate this.

In addition, the stiffening elements can also connect adjacent wooden planks from different layers, namely adjacent layers, to one another. Then they can also make it difficult or prevent the shifting of wooden planks of different layers against each other or of the layers as a whole against each other. In principle, this embodiment can also be present without the aforementioned connection between adjacent wooden planks within the same layer, which is, however, less preferred.

A preferred shape for the stiffening elements is cuboid, that is, rectangular in different sectional planes. This offers the already mentioned undercut-free profiles and is easy to manufacture. The same goes for the grooves. In contrast, the cross-connection means are shaped more complex, so z. B. with a trapezoidal or dovetail profile, as a threaded rod or the like.

A preferred choice for stiffening elements according to the invention consists of wood-based materials, preferably of (grown) wood. It is further preferred that the grain direction is approximately perpendicular to the direction of the cross-connecting elements and parallel to the plane of the plate and to the wooden planks. As the exemplary embodiments further illustrate, "end-grain blocks" in particular come into consideration. However, other wood-based material elements should also be considered, for example pieces sawn from multilayer boards. Overall, such material is strong, inexpensive and remains in the desired material class "wood".

The stiffening elements preferably have a rather limited length extension, but they can still connect more than two adjacent wooden planks. Preferably, however, the stiffening elements each connect exactly two adjacent wooden planks with respect to the respective direction, that is to say within one layer. In an embodiment with a plurality of wooden plank layers and stiffening elements connecting these layers, the same statement applies analogously in the direction perpendicular thereto, i.e. with regard to the wooden planks of different layers, so that a stiffening element can then preferably also connect exactly four adjacent wooden planks, two per layer .

A preferred embodiment of the stiffening elements different from the wooden elements are metal profile pieces including metal pipe pieces, in particular cuboid metal profile pieces, such as pipe or strip pieces with a rectangular profile. Such metal profile pieces (including pipe pieces, as I said) can remain very slim and still have high strength. The necessary grooves can accordingly be kept small so that the wooden planks are not weakened much. In the case of metal parts in particular, it can also be practical to have longer metal strips over a larger number of adjacent ones Let wooden planks run through in one layer. This also makes production easier because only one insertion process is required for each metal part.

The mentioned cross-connecting means in the sense of the ridge strips already described in the cited prior art or in the sense of the also already mentioned (wooden) threaded rods are provided in addition to the stiffening elements (or vice versa) and preferably form positive connections between adjacent wooden planks.

In contrast to the one cited at the beginning EP 08 019 598.5 In the present invention, neighboring wooden planks are preferably in direct contact with each other (except for the usual fluctuations due to moisture fluctuations or drying processes), which applies on the one hand to the neighboring wooden planks within one layer and additionally or alternatively to the wooden planks in neighboring layers. The adjacent wooden planks can have profiles on the touching surfaces within the same layer, which further increases the rigidity.

Furthermore, in addition to the cross-connecting means, connecting means can also be used with respect to a direction perpendicular to the plane of the panel, that is to say in particular for the (additional) connection of a plurality of wooden plank layers to one another. Conventional metal screws are particularly suitable for this. However, such measures are only indicated if the requirements are particularly high.

In the following, the invention is explained in more detail using an exemplary embodiment, wherein the individual features can also be essential to the invention in other combinations and, as already mentioned, relate implicitly to all categories of the invention.

the Figures 1 to 4 show various embodiments of the invention in perspective view and in the case of Figures 1 and 2 with parts of wooden planks omitted for illustration purposes;

Figure 5 shows an illustrative example to illustrate a variant for cross-connecting means, but this example does not belong to the invention because it has only one layer of wooden planks;
the Figures 6 and 7 show sectional views transversely to the longitudinal direction of the wooden planks, specifically to the exemplary embodiments from FIG Figures 2 and 1 .

Figure 1 shows a first exemplary embodiment of a panel element according to the invention with wooden planks 1 which are vertically oriented in this illustration and whose fiber direction is also essentially vertical. In fact, only a section is shown and the plate element shown continues both to the right behind and to the left in front in width; Furthermore, the wooden planks 1 are longer. However, the section shown already contains two cross-connecting means already known per se from the cited prior art, namely ridge strips 2. These are transverse wooden strips with also transverse fiber direction and, perpendicular to this, a dovetail profile. These ridges 2 are located in an interface between two layers of wooden planks 1. The front layer is partially cut away at an angle, which is used exclusively for better visibility of the inner structure of the plate element, so it is purely graphical.

As already explained in the prior art, the ridge strips 2 are preferably inserted without metallic connecting means and also without glue, specifically in a very dry state of the ridge strips 2 and the wooden planks 1 inserted along the longitudinal direction of the ridge strips 2. After a return to normal humidity, the ridges 2 are effectively and permanently jammed. They thus hold the wooden planks 1 together within a layer and in the fall In this exemplary embodiment, the wooden planks of adjacent layers, here the only two layers, are attached to one another.

Also shows Figure 1 a profiling of the outer surfaces of the wooden planks 1 abutting one another within a respective wooden plank layer, namely along with it grooves and elevations running through the longitudinal direction, which are complementary to one another and to that extent interlock in the assembled state of the wooden panel element. This profiling serves to improve the windproofness, particularly in the case of building wall elements. However, it can also increase the strength with regard to a relative offset of adjacent wooden planks relative to one another (in their longitudinal direction), and that already in the glue-free state due to an enlarged friction surface and, of course, in the glued state, which is also conceivable.

Additionally shows Figure 1 a stiffening element 3, namely a wooden strip 3 with a parallelepiped shape, which, like the ridge strips 2, is inserted into respective grooves of the wooden planks 1 of the two layers. In fact, however, the wooden strip 3 has an undercut-free shape, namely a rectangular profile. It can thus be simply inserted into the groove after the wooden planks 1 have been put together in one layer (and the groove has been produced). The main fiber direction of the wooden strip 3 is vertical, that is, as in the wooden planks 1 and different from the ridge strips 2.

It is also not necessary in this invention (although not excluded), the stiffening element 3 in the groove z. B. to brace by inserting in a particularly dry state and subsequent swelling. However, the stiffening element should sit in the groove 3 without play and fit. This is because it serves to block or make more difficult relative movements between adjacent wooden planks 1. If z. B. the left rear wooden plank and its neighboring wooden plank in the same (rear) layer in Figure 1 are loaded relative to one another along the longitudinal direction, that is to say "want to" shift against one another, the stiffening element 3 is braced in the groove in addition to the ridges 2.

In this sense, it can on the one hand simply be provided as an improvement to the previously known connection through the ridges 2 without great additional expense and increase the related rigidity. However, it can also be optimized for this function in a specific way.

In particular, it is preferred, regardless of this specific embodiment, that in the case of wooden stiffening elements, the grain direction is approximately parallel to the grain direction in the wooden planks 1 and not transversely to it as in the ridge strips 2. This results in a higher rigidity of the stiffening element 3 itself and in comparison to the ridges 2 and thus also a particularly effective improvement in the rigidity of the entire plate element.

It is namely not necessary and not even preferred within the scope of the invention to make the stiffening elements 3 particularly long in the transverse direction (parallel to the ridge strips) or even to make them in one piece over the entire wooden panel element. Rather, the stiffening elements 3 can be relatively short in this direction. In particular, as in Figure 1 the case, but not visible, is limited to bridging a small number of joints between adjacent wooden planks 1. For example, the stiffening element 3 in Figure 1 a small piece (about a quarter of a wooden plank width) over the (purely graphic, not real) boundary surface in Figure 1 (with the dovetail profiles visible in the section) and thus the in Figure 1 no longer visible interface between the left front wooden plank 1 and its left neighbor, also not shown, overlap in the same layer. At the same time, the stiffening element 3 overlaps according to FIG Figure 1 the joint between the left rear wooden plank and its in Figure 1 also drawn right neighbor in the back layer, compare also Figure 7 .

The stiffening element could perhaps also overlap the next joint in the back layer, but in any case only overlap a small number of one or two joints in the rear and in the front layer. Accordingly, it does not make any special circumstances to insert such a stiffening element 3 in the corresponding groove and to manufacture it in such a way that the fiber direction in Figure 1 is vertical.

The groove in turn can run through and the drawn reinforcing element 3 can be followed by a similar further (not drawn) or a plurality of such reinforcing elements 3 can be provided over the entire width of the wooden panel element.

One variant shows Figure 2 . The width of the stiffening elements 3 'is limited and they only overlap exactly one joint between adjacent wooden planks 1'. The correspondingly shorter stiffening elements are denoted by 3 '. In addition, a wooden plank layer is provided so that the middle wooden plank layer on both of its main surfaces (in Figure 2 front and rear and parallel to the main plane) has stiffening elements 3 'and also ridges 2'.

Figure 6 shows this embodiment (again in part) as a section transverse to the longitudinal direction of the wooden planks 1, the stiffening elements 3 'being shown in dashed lines. It can be seen that the width of the stiffening elements 3 'is almost half the width of the wooden planks 1' and thus (if the stiffening elements 3 'are not completely flush with one another) the gaps (or also joints) between the stiffening elements 3' are out of step, so to speak "lie with the joints between the wooden planks 1 'in the respective layers affected by them. In other words, the gaps or joints between the stiffening elements 3 'lie between the joints of the respective two layers (the layer above and the layer below). In this example, the gaps between the stiffening elements 3 '(which in turn occur in layers) are each approximately the same in both layers (but this is not necessary). Nor is it necessary to match the positions of the joints between the wooden planks 1 of the outer layers.

The background to this "out of step" arrangement is that the stiffening elements 3 'just serve to block possible relative movements along the joints of the wooden planks 1, as has already been explained.

Figure 7 shows an analogous section, but from the first embodiment Figure 1 . There the stiffening elements 3 are somewhat wider and in this case each capture a joint of the two respective layers, unlike in FIG Figure 6 . Of course, the stiffening elements could also be a little wider, as in relation to Figure 1 already explained.

Figure 3 FIG. 4 shows a further third exemplary embodiment, which initially has great similarities with the second exemplary embodiment in FIG Figure 2 Has. However, here the stiffening elements are not provided between the layers of wooden planks 1 ″, but in their outer surfaces and thus only in the outer layers Figure 3 at the height of the ridges 2. Although they do not fulfill their stiffening function there better than between the ridges (as in Figures 1 and 2 ), but this "concentrated" arrangement can be more at the edge z. B. be advantageous if the plate element rests there, that is, is still supported in the area of the ridges 2 and the stiffening elements 3 ″. This applies in particular to ceiling elements, that is, a horizontal arrangement of the in Figure 3 vertically standing panel element.

In addition, the stiffening elements are in their extension in the direction perpendicular to the main plane compared to those from the Figures 1 and 2 halved and thus roughly flush with the outer surfaces of the plate element. Especially with such an external arrangement, but also otherwise, it can be advantageous either to fix it in the manner described by inserting it very dry and then swelling it or to fix it a little with glue.

It also outputs in the exemplary embodiment Figure 3 (and also in Figure 4 ) three layers of wooden planks 1. According to the invention, four (and in special cases even more) layers can also occur. With a typical thickness of the wooden planks perpendicular to the plate plane of z. B. 6 cm result accordingly Total thicknesses in the order of 6 cm, 12 cm, 18 cm or 24 cm.

Figure 4 shows a further variant as a fourth embodiment. This again largely corresponds to the second and third exemplary embodiments with regard to the wooden planks 1 and the ridge strips 2. There are stiffening elements 3 ‴ provided, in the inner boundary surfaces between the wooden plank layers as in the second embodiment. However, these are relatively narrow metal strips made of z. B. aluminum or steel. These are significantly narrower in the longitudinal direction of the wooden planks 1 than the wooden stiffening elements 3, 3 'and 3 ". In addition, because it is not about one grain direction, they can be relatively extended in the width direction, if desired Less weakening of the wooden planks 1 ‴, because less volume is required. However, they contradict the frequent requests for metal-free or timber-limited construction.

A fifth example shows Figure 5 . It should be noted that this example does not belong to the invention because there is only one layer of wooden planks. Otherwise it illustrates a variant for the cross-connection means; namely, the previous ridge strips 2 as cross-connecting means have been replaced by threaded wooden rods 4, which naturally do not run on the outer surfaces of the wooden planks, but rather through the volume. Plate elements according to the invention can also be constructed and braced in a favorable manner with such wooden threaded rods. In principle, it is also true here that introduction is made easier in the particularly dry state.

Furthermore, similar to the third embodiment in FIG Figure 3 , superficial stiffening elements 3 "", again more in the edge area. The same explanations apply as for Figure 3 .

Figure 8 shows for the first embodiment Figure 1 exemplary the technical effect of adding the stiffening elements 3 '. The force-displacement diagram Figure 8 shows with the vertical axis a horizontal load at the head of the wall. So you have to choose the plate element Figure 1 with its lower Imagine the end firmly clamped and its upper end loaded relative to it, in a direction parallel to the main plane, i.e. in Figure 1 from left front to right back or vice versa. So it is about a bracing that wants to form a parallelogram from a rectangular plate element.

The horizontal axis in Figure 8 shows the shift in millimeters. Both axes can be viewed as divided into arbitrary units, because of course it depends on the height, the thickness, the width, the materials used and other things. Figure 8 so ultimately only serves as a qualitative explanation. In any case, the lines show a build-up and decrease of force with simultaneous measurement of the transverse displacement in the width direction.

The points relate to an element according to Figure 1 , but without stiffening elements 3 'and of course also without the necessary grooves, so essentially according to FIG EP 05 020 614.3 . Obviously, there is no linear force-displacement relationship, but rather the plate element becomes softer with increasing displacement, and then at some point gives way with essentially the same force, here just under 50 kN. However, the plate element in principle remains intact up to relatively large displacements, here at least up to 80 mm.

For many applications, however, it is less a question of maximum flexibility and more of a high degree of rigidity. Accordingly, according to the invention with the in Figure 1 The plate element equipped with the stiffening elements 3 'shown in the figure shows a more than doubled slope of the graph up to a breaking load of about 80 kN. The difference is due to the locking effect of the stiffening elements 3 '.

The invention thus enables a significant stiffening of the plate element in a simple manner and without significant additional costs. This basically also applies to other bending loads, in particular to a direction of force and deformation of the upper end of the plate element Figure 2 perpendicular to the main plane, i.e. from left back to front right or vice versa. For this, it is essential that the stiffening elements 3, 3 ', 3' are arranged in the intermediate levels between the wooden plank layers and thus also hinder the shifting of the layers relative to one another. In addition, the rigidity with regard to rotational deformations also increases, with mixed cases of relative displacements occurring here.

Multi-layer panel elements as in the Figures 1 to 4 are typically used more as wall elements. As already mentioned, especially when used as a ceiling element, stiffening elements 3ʺʺ as in Figure 5 to be provided in the area of the supports so as not to weaken the cross-section of the wooden planks in the unsupported area.

In principle, as in all exemplary embodiments, apart from the third, fewer "rows" of stiffening elements than those of ridge strips or cross-connecting means are to be provided (as in FIGS Figures 1, 2 and 4 two rows of ridges and only one row of stiffeners and in Figure 5 two rows of stiffening elements and three rows of cross-connecting means are provided). Furthermore, it is fundamentally preferred to provide the "rows" of the stiffening elements offset to those of the ridges or other cross-connecting means, in particular threaded wood screws, also compare the Figures 1, 2, 4 and 5 .

A preferred material for the wooden stiffening elements is spruce. Typical dimensions for the stiffening elements are (regardless of the exemplary embodiments) 1 to 20 cm in length along the direction of the wooden planks and, independently of this, 1 to 4 cm in thickness. The width in the direction of the cross-connection means can (cf. Figures 6 and 7 ) are in the order of about 40% of the width of the wooden plank to about the width of the wooden plank. In the case of metal in particular, however, the stiffening elements can also extend over just about the entire extent of the plate element in this direction. With metal In terms of length, the range between 1 and 6 cm is preferred, for wood and wood-based materials between 4 and 20 cm.

The second cited earlier application, namely the EP 08 019 598.5 , deals with the advantages and possible uses of spaces between the layers of wooden planks. This is by no means excluded in the present invention, although not shown, the flexural rigidity naturally deteriorating in the event of a load perpendicular to the main plane.

Claims (14)

1. A wood panel element

   comprising a plurality of planks (1-1‴) which are significantly longer in a longitudinal direction than in directions perpendicular thereto, wherein the direction of the grain is substantially parallel to the longitudinal direction and the planks are arranged parallel to each other,

   wherein the parallel planks (1-1‴) are arranged next to each other in at least one layer parallel to the main plane of the panel element,

   comprising transverse connectors (2-2‴, 4) for connecting adjacent planks (1-1‴) to each other in the at least one layer, and

   comprising additional stiffening elements (3-3‴) between adjacent planks (1-1‴) in the respective at least one layer,

   which stiffening elements (3-3‴) engage in grooves in the planks (1-1‴), namely without positive locking relative to a direction perpendicular to the main plane of the planks (1-1‴),

   characterised in that the planks (1-1‴) are arranged adjacent to each other in more than one layer parallel to the main plane of the panel element.
2. The wood panel element according to claim 1, comprising stiffening elements (3, 3′, 3‴) between adjacent planks (1, 1′, 1‴) of respective different layers.
3. The wood panel element according to one of the preceding claims, wherein each of the stiffening elements (3-3‴) and/or each of the grooves of the planks (1-1‴) has a profile free from undercuts relative to a sectional plane perpendicular both to the main plane of the panel element and to a longitudinal direction of a respective stiffening element.
4. The wood panel element according to claim 3, wherein each of the stiffening elements (3-3‴) and/or each of the grooves has a profile free from undercuts relative to a further direction in the main plane of the panel element.
5. The wood panel element according to claims 3 and 4, wherein the profile is cuboid.
6. The wood panel element according to one of the preceding claims, wherein the stiffening elements (3, 3′, 3ʺ, 3‴) are between 1 cm and 20 cm long in the direction of the planks (1-1‴) and/or have a thickness perpendicular to the main plane of the panel element of between 1 cm and 4 cm.
7. The wood panel element according to one of the preceding claims, wherein each of the stiffening elements (3, 3′, 3ʺ, 3‴) connects precisely two adjacent planks (1, 1′, 1ʺ, 1‴) relative to one direction.
8. The wood panel element according to one of the preceding claims, comprising metal profile pieces as stiffening elements (3"').
9. The wood panel element according to one of the preceding claims, wherein splines (2-2‴) are provided in planes between the at least two plank layers as transverse connectors and are aligned with their longitudinal direction transverse to the longitudinal direction of the planks (1-1"').
10. The wood panel element according to one of the preceding claims, wherein the transverse connectors (2-2‴, 4) are made from wood.
11. The wood panel element according to one of the preceding claims, comprising wooden threaded rods as transverse connectors (4) which are threaded through adjacent planks (1‴) of a respective plank layer.
12. The wood panel element according to one of the preceding claims, wherein the planks (1-1‴) of adjacent layers are in direct contact with each other and/or the planks (1-1‴) of a respective layer are in direct contact with each other.
13. The wood panel element according to claim 12, comprising complementary toothings on the contact-making surfaces of the planks (1-1‴) of a respective layer, wherein the profile is created in a sectional plane perpendicular to the longitudinal direction of the planks (1-1‴) and perpendicular to the layer.
14. Use of a wood panel element according to one of the preceding claims for a wall, a ceiling or a roof, in particular as part of a building.

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