EP1721714A1 - Composite wooden beam - Google Patents

Abstract

The frame has three longitudinal woods (L) that are stuck with one another and possess a height above 200 millimeters. Side surfaces (6) of the woods form vertical and horizontal adhesive joints (5), where the right side of the woods (L) stuck together with the vertical joints (5) lies outside. The side surfaces of the woods are processed by milling and include a flat cake structure (7). An independent claim is also included for a method for manufacturing a timber frame.

Description

The invention relates to a solid wood beam binder of glued together timbers.

In order to make high-quality long logs from tree trunks, such as e.g. As lumber is used to manufacture and thereby ensure a reasonably uniform quality, the logs are cut or formatted to the desired size and, if the blanks so cut blemishes, alias weak points, contain these defects or vulnerabilities are removed and the remaining Blank pieces glued by means of frontal finger joints to long wood. In this way, glued laminated timber, which is made up of several layers of longitudinally galvanized, glued together and offset wedge tine joints boards formed. Beam plywood is made of two, three or more longitudinally glued together beams, which may also be composed of sections, which are connected by finger joints.

A particular problem is the processing of thick wood, which is understood to mean trees that are about 40 cm in diameter at chest height. Such hardwood has the advantage of higher yield, when processed into structural timber. However, the wood properties are very heterogeneous, i. the strong wood requires a higher selection effort. In addition, a wet core or core cracks can cause problems. Strong branches also cause worse mechanical properties. For this reason, longwood made of hardwood is rarely cut in one piece from a trunk; usually it is necessary to cut out weak points and glue the sections, as mentioned above, by means of a finger joint to a long wood.

In order to ensure the quality of finger jointing made in such plants, destructive tests are carried out, whereby a break in a bending test intended for such a destructive test must not occur in the area of the finger jointing.

It has been shown that despite the automated error detection methods and despite subsequent detailed visual inspection when using such produced long timber unexpectedly fractures - eg caused by crushing fractures such as windbreak, gluing errors, gear errors, internal cracks, fiber deviations, etc. - can occur, so it Aspirations gives, design solid wood of Wooden structures in which the wood has a supporting function to exclude. This is particularly disadvantageous as this would no longer be a cost effective utilization as squared timber from thick wood, ie the hardwood would also have to be processed into multilayer glulam or beam laminated wood, in which hidden or not found defects or weak points in individual sections in consequence of multilayer bonding less significant.

The invention has as its object to provide a method for improving the quality of beam binders in order to use such beam binder also for highly stressed construction parts efficiently. In particular, the cross-sectional surcharges currently required due to the inhomogeneity of the wood should be able to be reduced.

As strong wood predominates in the forests and the proportion of hardwood is still rising, the invention has the special task of being able to use this hardwood with the required safety for constructions in which the hardwood takes over supporting functions, from the hardwood formed beam trusses are not formed in the manner of a glued laminated timber from individual together longitudinally glued layers of wood.

It is a further object of the invention to produce timber trusses with timber frame used for timber constructions, which also have very large cross-sections and can fully assume a supporting function, as equal as possible glued laminated glulam, and preferably even higher load than these. Compared to a glued laminated timber manufacturing steps should be minimized and also the glue consumption be reduced.

This object is achieved in a beam binder of the type described above in that it is formed from at least three long timbers with at least one standing and a horizontal adhesive joint, preferably with a height above 200 mm, with the right side of each other sticking with stationary adhesive joint long woods is provided outside.

A particularly good wetting with adhesive and a good adhesion or bonding of the long timbers with each other to form a beam binder is ensured when the reaching together for bonding standing side surfaces of the long timbers are processed by bonding before bonding.

Depending on the required strength of a beam binder, it may be formed of two or more juxtaposed and two or more superposed and glued together long woods, the beam binder can be used from longwoods the same or different dimensions.

According to the invention, a particular optical advantage for the wood architecture is given, especially since the standing side surfaces of a beam binder have a flat structure and not, as in a glulam, only narrow glued together boards with the adhesive joints recognize.

Preferably, a beam binder is characterized in that it comprises at least one long wood having a height of over 100 mm, preferably up to about 300 mm, and a width of over 40 mm, preferably up to 100 mm.

A further advantageous embodiment is characterized in that the beam binder has at least one long wood with a height of over 140 mm, preferably up to 600 mm, and a width of over 40 mm.

In order to be able to use particularly high strength zones of the splint area of a trunk in the heavily loaded area of a carrier, according to a preferred embodiment a beam binder is characterized in that long timbers are used whose narrow side areas are formed by sapwood of a thick wood.

In order to ensure a flat structure on the lower or upper side of a beam or beam binder, a beam binder is expediently characterized by the arrangement and bonding of at least one long timber on the underside and / or upper side, which extends over the entire width of the beam binder and after below or above has a flat structure.

Suitably, a beam binder is characterized in that it is formed from three longwoods, consisting of two with a standing adhesive joint glued to a beam longwood and glued to this beam with horizontal adhesive joint screed, with a width of the beam.

A further preferred variant is characterized in that it consists of at least two long sticks bonded together by means of a standing adhesive joint Bar is formed, wherein one of the beams on the underside of the beam binder and one of the beams at the top of the beam binder is arranged, and between these bars either a screed or two also with a sticking joint stuck together planks or other beams are provided.

Preferably, a beam binder is characterized in that provided on the underside of the beam binder long woods on the underside and preferably also on the top of the beam binder at the top of sapwood, whereby the higher strength values of the sapwood come into effect effectively.

In order to use a beam binder for higher loads, a method for producing a beam binder is characterized in that long sticks are glued together, the modulus of elasticity was determined on logs, wet lumber and / or on dry lumber, which advantageously in the tension zone , preferably also in the pressure zone, long logs with an E-modulus above a certain limit, such as> 13,000 N / mm ² , are used, and that optionally provided therebetween long timbers are selected from long timbers with a lower modulus of elasticity.

Suitably, the modulus of elasticity is approximately determined before bonding by means of ultrasonic measurement or sound measurement or by bending test or tensile test.

For efficient processing of hardwood, hardwood, in particular hardwood with a diameter at the end of the pile of at least 300 mm, processed by milling to a wood edge squared timber and then processed the squared timber preferably by band saws to longwoods, where appropriate for better utilization and reduction of waste wood sawing Long timbers is carried out approximately along or parallel to the pith of the square timber.

In this case, the bandsaws is advantageously carried out at about half the feed rate of the milling, whereby a high milling speed can be fully exploited with the provision of two downstream bandsaw lines.

A further variant of the method is characterized in that the long timbers in the arrangement in which they are cut from the trunk are in turn assembled and glued to form a beam binder, so that the beam binder / trambinder has a "natural annual ring layer". Here, the sapwood part comes to lie on the bottom and top of the beam binder.

The invention is explained in more detail below with reference to the drawing, wherein FIGS. 1 to 3 formed from long timbers beam according to the prior art in the oblique view. Fig. 4 illustrates a so-called "glulam" made of glulam. Figures 5 and 7 to 15 show beam binders according to the invention, Figures 6, 16 and 16A illustrate cutting plans for thick wood. Fig. 17 shows a ceiling support in a horizontal arrangement.

1 to 3 relate to conventional beams 1, 2, 3. FIG. 1 shows a duobalk 1, FIG. 2 shows a trio bar 2 and FIG. 3 shows a quattro bar 3.

These bars 1 to 3 formed from timbers L each have a standing adhesive joint 5, resulting in side surfaces 6 with a flat structure 7. The width 8 of the long sticks L to be glued together is preferably 50, 60, 70, 80 or 100 mm, resulting in beam widths 9 for a duoboard between e.g. 100 and 200 mm or even wider. The height 10 of the long lumber L is preferably between 160 and 300 mm.

Particularly high-adhesion adhesive joints 5 are obtained when the adhesive together reaching for bonding standing side surfaces of the long logs L are processed before bonding by milling. As a result, a very good wetting of the adhesive surfaces is ensured with adhesive, which also adhesive savings are possible.

According to the invention, the beam width 9 always extends over at least two widths 8 of the long timbers L; in the duobalk over two, in the tri-bar according to FIG. 2 over three and in the quattro beam according to FIG. 3 over four long-timbers L.

In Fig. 4 is a conventional "glue beam" 11, which is formed from boards or slats 12 as glued laminated timber illustrates. The height 13 of the individual boards is usually from 3 to a maximum of 4 cm. The width 14 of the boards 12 is usually between 80 mm and 200 mm, possibly 240 mm. Such a "glue binder" 11 is expensive to manufacture, and it is a large amount of glue or adhesive used. Its side view reveals all the glued joints and only a simple structure of the wood.

Instead of such a "Leimbinders" according to the invention a beam binder 15 may be provided, which is formed as shown in FIG. 5, for example, Duobalken 1, each with a stationary adhesive joint 5, wherein three such Duobalken 1 superimposed and each other are glued. The width 16 of such a beam binder is preferably also between 100 and 200 mm, but may also be higher, for example when trio or quattro beams 2 or 3 are superimposed and glued together. Of course, it is possible, the number superimposed and glued together beams 1, 2, 3 depending on Erfodernis, ie depending on the desired cross-section set.

The advantage of such a beam binder 15 with respect to a laminated beam 11 formed from boards 12 or glued laminated timber is not only in the appearance - in side view is a nice flat structure 7 can be seen - but also in the load capacity. An essential criterion is that it can be made of thick wood.

With dashed lines is indicated in Fig. 5 that at the bottom and / or top of the beam binder 15 long sticks L can be adhered, so that the bottom or the top each has a flat structure and thus optically a bottom of a from boards 12th formed "Leimbinders" 11 corresponds.

In order to take advantage of the particular strength of sapwood 17 for beam binder 15, hardwood 18 is cut with diameters of about 300 mm according to the cutting plan shown in Fig. 6. This allows e.g. Long timber L in the height 10 - depending on the diameter of the hardwood - from about 140 to 600 mm produce their narrow side regions 19 from the outside, i. the area of the sapwood 17 of a hardwood 18, are cut.

If, for example, four such long sticks L are glued to a beam binder 15 (see FIG. 7), a particularly heavy-duty beam binder 15 results, especially since the tension and compression zone of the beam binder 15 is formed by sapwood 17, which, as mentioned above, is a particularly strong high strength, in particular a particularly high tensile strength, has. Sapwood 17 has been proven to have a 20% higher load capacity than heartwood.

A beam binder 15 of this type also has a lateral flat structure 7. A beam binder 15 - with or without central parting line - this dimension is also referred to as Trambinder 15.

Beam binder 15 or Trambinder, as described above, are particularly inexpensive to produce. As can be seen from FIG. 6, it results in only little wood loss and only a few work steps are necessary for its production.

FIGS. 8 and 9 show duobalks 1 made of hardwood, which are formed of long timbers L with a height 10 of more than 140 mm and a width 8 of more than 40 mm. At the bottom of these duobalk 1 sapwood 17 is also present. If such duobalkers 1 are glued one above the other, beam binders 15 or trammers 15 (see FIGS. 10 and 12) with very large heights result, wherein the sapwood 17 is present in each case in the tension zone and in the pressure zone.

Fig. 11 shows a Trambinder 15, which is made of long timbers L, which are cut from hardwood, which are composed of trio balkes 2, is formed. The peculiarity of Trambinder shown in Figs. 11 and 12 can be seen in the fact that the long sticks L in the arrangement in which they were cut from the Starkholzstamm, in turn, assembled and glued to a Trambinder 15. This results in a so-called "natural annual ring layer", again in the tensile and pressure zone sapwood 17 is present.

In order to keep the sapwood zone approximately constant over the length of the beam binder or Trambinder 15, a wedge-shaped core zone can be cut out of the log, the pitch angle of the core corresponding to half the cone angle of the tapered trunk.

A beam binder 15 according to FIGS. 11 and 12 has the advantage that it is stress-relieved, especially since the hardwood is separated in its fresh state, the long sticks L thus formed are dried and planed, and then glued to the beam binder 15, as it were, stress-relieved.

In Fig. 13, a beam binder 15 or Trambinder is illustrated, the tensile and compressive zones are formed by Quattrobalken 3, whereas the central zone of two long timbers, such as planks B, is formed, the total width of the width 9 of the Quattrobalken 3 corresponds.

Figures 14 and 15 show further beam binders 15 formed of duobalk 1 and long timbers L, such as planks B. It is, of course, also possible to form a beam binder 15 which is at the bottom and top of a tri-bar 2 and therebetween two adjacent ones Planks B is formed. Beam binders 15 with a height of over one meter can be readily manufactured.

FIG. 16 likewise illustrates a cutting plan for thick wood, the figures entered in this figure referring to the cross sections of the individual long lumbers L cut from the hardwood. Of course, it is possible to free the two centrally located long timbers from the core zone, as illustrated in Fig. 16A. According to the cutting plan, the main product has an utilization of 69.38%, for the side goods only 3.37%, so that residual wood accounts for 17.46% and sawdust to 9.16% of the timber volume of the hardwood.

A particularly good utilization of hardwood can then be achieved if the long timbers are cut according to the curvature of the trunk, so as the course of the pith, or parallel to it, then be formed by cross-cutting long wood sections, which by joining by means of finger joints Longwoods are used in the straightest possible condition for the production of beam binders of great length.

Preferably, the roundwood logs are processed with cutting units to wood edged squared timbers, by milling, which is done optimally with the Zopfende advance.

Band saws can then be used to cut long-handled lumber from square-edged squared timbers. Since the milling can be done with about twice as high feed rate as the bandsaws, it is advisable to rearrange two bandsaw systems of the milling machine for the production of forest-edged squared timbers.

In Fig. 17, a ceiling support in a horizontal arrangement, e.g. with a width of over 1000 mm, which has a flat structure as a visible surface.

In order to be able to use beam binder 15 according to the invention for greater loads, it is advisable to determine the E-modules on the long-timbers L, which can be done for example by ultrasonic measurement, sound measurement or by means of a bending test or tensile test. Advantageously, such checked long timbers with an E-modulus above a certain limit, such as> 13,000 N / mm ² , find use in the tension zone or pressure zone of a beam binder 15. The determination of the modulus of elasticity only needs to be approximated here and can be carried out in the fresh state of the wood or in the dry state of the wood.

Fig. 18 illustrates a particularly favorable arrangement of the long timbers L in a double-duo beam binder 15. With full lines, an I-beam is located. The annual ring layers running according to the straps of the I-beam, preferably of sapwood, are obviously responsible for the very high strength values and rigidity values found in these investigations after initial investigations.

Claims (19)

Solid wood beam truss (15) made of long logs (L) glued together, characterized in that it is formed from at least three long timbers (L) with at least one standing and one lying glued joint (5), preferably with a height above 200 mm, wherein the right side of each other with standing adhesive joint (5) glued long woods (L) is provided on the outside. Beam binder (15) according to claim 1, characterized in that the adhesive joint (5) forming side surfaces of the long timbers (L) are machined by milling. Beam binder (15), characterized in that it is formed from two or more side by side and two or more superimposed and bonded together long timbers (L). Beam binder (15) according to one of claims 1 to 3, characterized in that the standing side surfaces (6) have a flat structure (7). Beam binder (15) according to one of claims 1 to 3, characterized in that it comprises at least one long wood (L) having a height (10) of over 100 mm, preferably up to about 300 mm, and a width (8) of over 40 mm, preferably up to 100 mm. Beam binder (15) according to one of claims 1 to 5, characterized in that it comprises at least one long wood (L) having a height (10) of over 140 mm, preferably up to 600 mm, and a width (28) of over 40 mm , Beam binder (15) according to any one of claims 1 to 6, characterized in that long timbers (L) are used, the narrow side regions (19) of sapwood (17) of a hardwood (18) are formed. Beam binder (15) according to any one of claims 1 to 6, characterized by the arrangement and bonding at least one long wood (L) at the bottom and / or top, which extends over the entire width (9) of the beam binder (15) and also after has a flat structure (7) below or above. Beam binder (15) according to one of claims 1 to 8, characterized in that it is formed from three long timbers (L), namely two with a standing adhesive joint (5) sticks (L) glued to a beam (1) and a screed (B) glued to this beam (1) with a lying glue joint (5), with a width of the beam (1). Beam binder (15) formed according to any one of claims 1 to 9, characterized in that it is formed from at least two beams (1) formed together by means of a standing adhesive joint (5) glued beams (1), wherein one of the beams (1, 2, 3) is arranged on the underside of the beam binder (15) and one of the beams (1, 2, 3) on the upper side of the beam binder (15), and between these beams either a screed (B) or two also with standing Adhesive joint (5) bonded together planks (B) or other beams (1, 2, 3) are provided. Beam binder (15) according to any one of claims 1 to 10, characterized in that on the underside of the beam binder (15) provided long timbers (L) at the bottom and preferably also at the top of the beam binder (15) at the top of sapwood ( 17). A method for producing a beam binder (15) according to any one of claims 1 to 11, characterized in that long woods (L) are glued together, the modulus of elasticity was determined on logs, wet lumber and / or on dry lumber. A method according to claim 12, characterized in that in the tensile zone, preferably also in the pressure zone, long timbers (L) with an E-modulus above a certain limit, such as> 13,000 N / mm ² , are used, and that optionally provided therebetween long timbers (L) are selected from longwoods (L) with a lower modulus of elasticity. A method according to claim 12 or 13, characterized in that the modulus of elasticity is determined approximately before bonding by means of ultrasonic measurement or sound measurement or by bending test or tensile test. Method according to one of claims 12 to 14, characterized in that hardwood, in particular hardwood with a diameter at the end of the pigtail of at least 300 mm, is processed by milling to a wood edge squared timber and that the squared timber is then preferably processed by band saws to longwood (L) , A method according to claim 15, characterized in that the sawing to long timbers (L) is carried out approximately along or parallel to the pith of the square timber. A method according to claim 15 or 16, characterized in that the band sawing is carried out at about half the feed rate of the milling. Method according to one of claims 12 to 17, characterized in that the long timbers (L) in the arrangement in which they are cut from the trunk, in turn, assembled and glued to a beam binder (15). Use of a beam binder according to one of claims 1 to 11 as a wall or - in horizontal arrangement - as a ceiling element.

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