FI63102C - FLERSKIKTSBALK MED ETT STRAENGSPRUTAT MITTSKIKT AV SMAO STYCKEN AV NATURMATERIAL - Google Patents

Description

I -, ^ rRl ANNOUNCEMENT, -7 Λ n 0 ™ UTLACG NI NGSSKRI FT 63l 0 2 c (4S) 11J41983 ^ (51) K ».lk? /Lnt.a.3 E 04 C 3/29 FINLAND — FINLAND ( 21) i> iMnttih * k * BH «-p» t * nt «ek» Itai 791 ^ 07 (22) H »k * ml» cloud »—An« 8ki * lnpd «g 02.05-79 ^ ^ (23) AlkupMvft - Giltlgh «t * dif 02.05.79 (41) Tullut lulklMkal - Bllvlt off« ntll | 11/27/79

Patent and Register Office. Nihtlviktlpan * |. ku «lj« lk * and date— 31 12 q2

Patent and registration certificates '' Anabktn utligd och utLtkrifMn pubtkwrad J

(32) (33) (31) Requested in front of the office — Begird prtorltM 26.05.78

Federal Republic of Germany-Förbundsrepubliken TVskland (DE) P 2823053-7 (71) (72) Anton Heggenstaller, Miihlenstrasse 9, 8891 Unterbernbach,

Federal Republic of Germany-Förbundsrepubliken lyskland (DE) (7 * 0 Oy Kolster Ab (5 * 0 Extruded middle layer beam consisting of small parts of natural materials - Flerskiktsbalk med ett strängsprutat mittskikt av smä styeken av naturmater

The invention relates to a multilayer beam, in which the middle layer occupying a substantial volume of the beam consists of natural materials, e.g. wood, straw, sugar cane waste, cotton straw, agave fibers, waste fibers or the like, with.

Such a beam, although consisting only of small parts of wood, has become known from U.S. Pat. No. 2,717,420. It has a square cross-section with a through-going cavity of circular cross-section in the center. From the side surfaces, the beam is glued together with metal strips, which apparently should provide an interaction with the extruded body and thus higher strength.

German application 2 407 642 further discloses a wooden beam which is likewise compressed from small parts, the essential feature of which is that it comprises at least three superimposed layers extending along the entire length of the beam, both outer layers containing mostly chips, the fibers being oriented mainly in the longitudinal direction of the beam, and the middle layer has for the most part chips with their fibers oriented substantially in the transverse plane of the beam. In practice, such a beam with the described structure can only be produced by heating the glued chips in a mold and subjecting them to compression pressure. Thus, however, the beam can only have a length corresponding to the mold, but practically insufficient.

Experience has shown that neither of the previously known beams has in practice proved to be valid and has not replaced a beam grown in nature. In the case of a beam of the type mentioned at the beginning, which is coated with metal plates, there is a risk that the adhesive joint will come off due to different thermal stresses. In the case of strong thermal differences, the metal layer contributes to the deformation of the beam, as it has a substantially higher thermal conductivity and the consequent expansion. In addition, the synergy suffers. According to German application 2 407 642, sufficient load-bearing strength is not achieved completely, even if the manufacturing method does not allow economical manufacturing and superiority over a beam grown in nature.

In practice, the problem is hitherto unsolved for the production of beams from small parts of wood or similar natural materials which are superior to naturally grown beams in terms of both cost and aging resistance, especially in terms of expansion and shrinkage. It is the object of the invention to solve this problem.

Based on U.S. Pat. No. 2,717,420, which is incorporated herein by reference, it is an essence of the invention that the middle layer consists of a mixture of coarser and finer needle chips having a specific gravity of about 450-750 kg / m 2 and the chips or fibers are oriented substantially longitudinally. natural wood boards with a thickness of approximately 1: 6 and 1:25 compared to the thickness of the middle layer extending in the same direction.

The beams according to the invention have a surprisingly high bending-breaking load and buckling-breaking load, which was not expected in view of the known theories 3 631 02. The prior art (U.S. Pat. No. 2,717,420) conveys the impression of providing the extruded middle layer with the necessary rigidity by means of an overlaid metal layer, from which it can be deduced that only a high-strength cover layer can be suitable for the required stiffness. The German application publication 2 407 642 does not provide any proposal at all in terms of the layout of the task. It is all the more surprising that by gluing simple wooden boards on top of an extruded middle layer, a substantially higher load-bearing capacity can be achieved than would be expected from the prior art. This advantage is apparently due to the extrusion of coarser and finer needle chips while maintaining a certain specific gravity, with the orientation of the position of the needle chips being important. The fine needle supports have a long-fiber structure with a length of about 3-12 mm. The length of the coarse needle chips is up to about 30 mm without deviating from the long-fiber structure. The invention avoids the deliberate use of flat chips. The coward beams of the invention are thoroughly homogeneous in terms of the middle layer compared to the previously known beams and press-chip boards, respectively. This means that despite the desired trend, there is a uniform chaining of chips of different lengths over the entire cross-sectional area.

Examples of practical load-bearing forces can be found in the description.

In addition, the invention has the other advantage that materials of the same quality are glued together and the extruded body as a central body then gives a substantially higher load-bearing capacity than glued when glued together with sawn or planed natural wood boards. The shape resistance to weathering is also substantially higher than that of beams made of grown wood, because the beams according to the invention do not show deformation under the influence of the weather and the risk of cracking and decay can be prevented by suitable handling of small parts before pressing. The beams according to the invention can be stacked on top of each other to form both partition walls and other load-bearing walls.

4 63102

They are also suitable as support beams, tie beams, structural elements and the like.

According to the idea of the invention, it turns out to be advantageous that the middle layer is made rectangular in cross-section and has a through-going cavity made of elongated cross-section, the distance of the cavity wall from the closest outer surfaces of the middle layer being approximately equal. Depending on the function to be performed by the multilayer beam according to the invention, the outer layers can be arranged both on the narrow side and on the wide side of the middle layer. In particular, it is recommended to make a groove and a rib on the two opposite outer sides of the middle layer and leave them uncoated. In this case, it is preferably the narrow side surfaces of the middle layer on which the groove and the rib are made.

However, if it is desired to provide cover layers in the groove and rib region, then according to the invention it is advisable to arrange the cover layers in several parts, whereby in the transition area of the side surfaces and the groove or rib, respectively, the individual cover layers are spaced apart and the edges are oblique in this area. In this way, the joining of the beams is not hindered, but a very high strength is nevertheless achieved.

According to the invention, it is further proposed to extrude a rectangular middle layer in a position in which the longer edge is vertical. Thus, if a multilayer beam with a rectangular cross-section has to be set aside in use, it is nevertheless made high. This method of manufacturing has the advantage of the same constant density of compressible wood chips over the entire length and cross-section. If such a multilayer beam were to be made lying down, then the small parts would have to overcome the higher friction with the stationary mandrel of the press when they would have to fall freely into the lower area of the press cylinder. In addition, the formation of shrinkage cavities in the area below the mandrel could then occur.

The invention further relates to covering all the outer surfaces of the middle layer with covering layers of natural wood boards. In this case, it is recommended that in the load state, the vertical cover layers are fastened between the horizontal cover layers.

5 63102

In addition, it proves expedient to chamfer the corners of the middle layer, whereby the advantage is obtained that in the corner area regular gluing of the middle layer with the cover layers can take place. The mixing ratio of the coarse and fine needle chips in the embodiment of the invention is about 50:50. In this case, it is advantageous if about 2/3 of the needle chips are oriented in the longitudinal direction of the beam, the rest transversely to it. According to the invention, the maximum rigidity of the beam thus produced and a uniform structure, which is considered to be the mutual padding of the needle chips, are thus achieved with the entire cross-section of the middle layer.

The invention also relates to the possibility of connecting two or more middle layers directly to one another, in particular by gluing together, and to fit the cover layers only to the outer sides of the middle layers. In this way, beams with very high load-bearing capacity can be produced with simple and small and therefore inexpensive presses.

In addition, it may be advantageous to fill or foam-fill the cavity in the middle layer, in particular with insulating substances, e.g. polyurethane. But the same cavity can also be used advantageously to place the mounting material in the invisible.

The details of the invention are shown schematically and by way of example in the drawing.

Figures 1-5 show cross-sections of multi-layer beams with a rectangular profile and two opposite cover layers.

Figures 6-9 show cross-sections of multilayer beams with cover layers on each side.

Figures 10 and 11 show cross-sections of other beams in a further embodiment.

In the embodiment of Figure 1, a multilayer beam according to the invention is shown in cross-section, the middle layer 1 of which consists of an extruded body. How such extruded bodies can be produced on a large scale is described in German application 2,535,989. The middle layer 1 has cover layers 2 along its longer side surfaces, which are natural wood, in particular sawn or planed wooden boards. In the middle of the middle layer 1 there is a through cavity 3 having the shape of a hole with an elongated cross-section. In this case, it must be taken into account that the distances of the cavity walls 3 to the side surfaces of the middle layer 1 are approximately equal. On the narrow end sides of the middle layer 1 there is a groove 5 and a ridge 4, which are profiled so that the multilayer beams can be stacked on top of each other to form a wall, in particular a partition wall.

In an embodiment of the invention, the multilayer beam has a total width a of about 156 mm, a total height b of about 200 mm, the wall thickness c of the cover layers 2 being about 8 mm and the width of the middle layer being about 140 mm. A beam with these dimensions has a bending breaking load of about 3020 kg with a fastening length of 3000 mm. These and subsequent values have been established by state materials research institutes.

In the example of Figure 2, the ratio of the wall thickness of the cover layers 2 to the thickness of the middle layer 1 is higher. In this case, again as an exemplary embodiment, the wall thickness of the cover layer 2 is 20 mm, while the other dimensions remain the same. The load-bearing capacity of this beam is correspondingly higher than the load-bearing capacity according to Fig. 1, whereby the dimensions of the middle layer 1 are required to remain the same without correspondingly higher costs.

In general, it can be assumed that it is advisable to choose the ratio of the thickness of the cover layer 2 to the thickness of the middle layer 1 between approximately 1: 6 and 1:25. In special cases where other loads have to be taken, these ratios can naturally be exceeded or undershot. Advantageously, the thickness of the cover layer 2 of the order of 20 mm can be used, especially in the case of loaded beams.

In the exemplary embodiments of Figures 3 and 4, the narrow sides of the middle layer 1 are covered with cover layers 2. The supports are regularly shown in the drawing in the loading state. In the example of Figure 3, the cover layer 2 is made relatively thin-walled, e.g. 8 mm thick, while the height of the middle layer 1 is again about 200 mm. In the example of Figure 4, on the other hand, the cover layer 2 is in turn made thicker, e.g. 20 mm, while the height of the middle layer 1 remains as a sauna. The bending fracture load of the beam shown in Fig. 4 is again about 5200 kg with a fastening length of 3000 mm.

Fig. 5 shows a frame beam for prefabricated structures, in which the cover layers 2 are glued to the wide side surfaces of the middle layer 1 and the outer surface of which can additionally act as a visible surface or a flat substrate for plywood, wallpaper or the like.

In the embodiments of Figures 6-9, it is assumed that all the outer surfaces of the middle layer 1 are surrounded by the cover layers 2, 7. The cover layers 2 cover a narrow area of the middle layer 1, the cover layers 7 a wide area. These cover layers 2, 7 also consist of natural wood boards.

In the example of Figure 6, the wall thickness of a single cover layer may be 8 mm, while the dimensions of the middle layer 1 are 140 x 200 mm according to Figure 1. In the example of Figure 7, the cover layer is shown, for example, 20 mm thick. Such beams are particularly suitable as roof girders and the like.

In the example of Figures 8 and 9, we start from the middle layers 1 with a square cross-section, in which the through-cavity 3 has a circular shape, respectively. In the example of Figure 8, the wall thickness is again 8 mm, while the width of the side surfaces of the middle layer 1 is about 145 mm. With the inner dimensions remaining the same, in the example of Fig. 9, the wall thicknesses of the cover layers 2 are again chosen to be 20 mm. The beam fracture load of the beam shown in Fig. 9 is 7300 kg with a fastening length of 3000 mm and the buckling fracture load of 32000 kg.

In the embodiments of Figures 6-9, the bar shown shows the operating position so that the load acts vertically. The cover layers 7 on the sides are fastened between the upper and lower cover layers 2 in these embodiments. In addition, the corners 6 of the middle layer 1 are chamfered in the examples of Figures 8 and 9. With the latter measure, it is achieved that the gluing of the cover layers 2, 7 together with the middle layer 1 can be carried out without interference, without the load-bearing force of the support then being affected.

The middle layer 1 of the beams shown in all figures consists of needle chips mixed with binders, which may comprise e.g. 50% coarse chips and 50% fine chips. The durability of the beams is best when about 2/3 of the needle chips are oriented in the longitudinal direction during extrusion, which can be achieved by mixing the chips, introducing them into the compression chamber and determining the pressure, as suggested by the parents. In this case, the reduction of the proportion of other shapes, e.g. flat shavings, to an unavoidable minimum must be taken into account.

8 63102

The example of Fig. 10 shows a beam with a groove 5 and a rib 4, the cover layers 2a, 2b and 2c of which are spaced apart from each other and which are possibly provided with chamfers 9. In this way, heavily loadable walls can be obtained.

Figure 11 shows the immediate joining of two middle layers 1, on the free outer surfaces of which cover layers 2 are glued. Such a multiple connecting beam can be manufactured with low compression costs in order to obtain a particularly high load-bearing capacity.

It goes without saying that the dimensions of the beams can be changed arbitrarily in the desired way and according to the requirements. The invention therefore does not extend only to concrete embodiments, but extends to all variations which will become apparent to a person skilled in the art on the basis of the information provided by the invention.

Claims (13)

A multilayer beam, wherein the middle layer (1) occupying a substantial volume of the beam consists of natural materials, e.g. wood, straw, sugar cane waste, cotton straw, agave fibers, waste fibers or the like, binder-mixed, extruded 3 parts ) and the outer layers (2, 7) are glued together with the middle layer (1), characterized in that the middle layer (1) consists of a mixture of coarser and finer needle chips with a specific weight of about 450 ... 750 kg / m and the chips or fibers are oriented mainly in the longitudinal direction of the beam and that the outer layers (2, 7) consist of sawn or planed natural wood boards with a thickness of approximately 1: 6 and 1:25 compared to the thickness of the middle layer extending in the same direction. A beam according to claim 1, characterized in that the middle layer (1) is made rectangular in cross section and has a through cavity made in an elongate hole (3) in cross section. A beam according to claim 1 or 2, characterized in that the distance of the cavity wall (3) to the nearest outer surfaces of the middle layer (1) is approximately equal. Beam according to one of Claims 1 to 3, characterized in that the two opposite outer sides of the middle layer (1) are provided with a groove (5) and a rib (4) and are not provided with a cover layer. Beam according to one of Claims 1 to 4, characterized in that the middle layer (1) provided with the groove (5) and the rib (4) is provided with cover layers (2a, 2b, 2c) of groove (5) and rib (4). on the sides having a distance (8) with respect to each other in the transition area of the side surface and the groove (5) or the rib (4), respectively, and possibly beveled (9) at the edges. Beam according to one of Claims 1 to 5, characterized in that the rectangular central layer (1) is extruded in a position in which the longer edge is in the vertical direction. Beam according to one of Claims 1 to 6, characterized in that the cover layers (2, 7) made of natural wood board are glued to all the outer surfaces of the middle layer (1). 10,631 02 A beam according to claim 7, characterized in that in the load state, the vertical cover layers (7) are fastened between the horizontal cover layers (2). Beam according to Claim 7 or 8, characterized in that the corners (6) of the middle layer (1) are bevelled. 9 63102 Beam according to one of Claims 1 to 9, characterized in that the mixing ratio of the coarse and fine needle chips is approximately 50:50. Beam according to one of Claims 1 to 10, characterized in that approximately 2/3 of the needle chips are oriented in the longitudinal direction of the beam, the rest being transverse to it. Beam according to one of Claims 1 to 11, characterized in that the two or more middle layers (1) are connected directly to one another, in particular glued together, and in that the cover layers (2) are arranged only on the outer sides of the middle layers (1). Beam according to one of Claims 1 to 12, characterized in that the cavity (3) in the middle layer (1) is filled or, respectively, foamed, in particular with insulating substances, e.g. polyurethane. 11 63102