Abstract
The invention relates to a simple and safe method for manufacturing a wood part joint, in particular a cross-laminated timber for a house wall, from a plurality of individual layers which are laid as longitudinal layers (L) and transverse layers (Q) at an angle to one another and subsequently joined, preferably glued and pressed, at their mutually facing main surfaces. According to the invention, at least the boards of the longitudinal layer (L) are pre-fixed in their transverse direction using an elongate string element (2) at least in the end region, in particular using beading pressed into a groove. The invention also relates to a corresponding device for carrying out the method, wherein a feed for the elongate string element (2) is provided which can independently also be used for a wood part joint in which abutting, shorter pieces of wood are pre-fixed in the longitudinal direction to a board.
Claims
1. Method A method for producing a wood part connection, in particular a cross-laminated timber for a house wall, made of several individual layers, which are preferably laid as longitudinal layers (L) and transverse layers (Q) at an angle to one another and finally joined, preferably glued and pressed, on their main surfaces (H) facing one another, characterized in that at least the boards of the longitudinal layer (L) are pre-fixed in their transverse direction with an elongated string element at least in the end area, in particular with a beading each.
2. The method according to claim 1, wherein the beading consists of a plastic, textile or metal wire or tensile natural fibers.
3. The method according to claim 1, wherein the beading is inserted into a sawed-in or milled-in groove, in particular employing an axial preload.
4. The method according to claim 3, wherein the groove is cut at an angle to the main surface (H) of the boards.
5. The method according to claim 1, wherein the String element is pulled off a roller and pressed into the groove, in particular with an axial preload.
6. Method according to claim 1, wherein the beading is provided on the edge of cutouts for building openings.
7. A device for carrying out the method claim 1, wherein a laying table (T) is provided for pre-fixing the boards, in particular with a beading, above or below which a feed for the elongated string element is arranged.
8. The device according to claim 7, wherein a milling cutter or saw is arranged adjacent to the feed, which preferably generates the groove in the transverse passage of the boards.
9. The device according to claim 8, wherein the milling cutter or saw can be moved over the respective individual layer (L or Q) by means of a portal.
10. The device according to claim 8, wherein at least one pressure roller for the beading is arranged adjacent to the milling cutter or saw in order to press it into the groove, in particular with an axial preload.
11. The device according claim 7, wherein the groove is oriented at an oblique angle to the longitudinal axis of the boards.
12. A wood part connection for several pieces of wood, in particular for boards, planks or lamellas for use according to claim 1, with at least one transverse joint on which the pieces of wood are joined, in particular glued, in the longitudinal direction of the boards, planks or lamellas, wherein the pieces of wood are pre-fixed in their longitudinal direction (LR) to form a board with a string element, in particular that they are braced with a beading.
13. The wood part connection according to claim 12, wherein the beading consists of a plastic strand, textile or metal wire or tensile natural fibers.
14. The wood part connection according to claim 12, wherein the transverse joint is designed as a butt joint.
15. The wood part connection of claim 12, wherein two grooves are provided which are arranged on opposite main surfaces (H) of the pieces of wood forming a board, wherein preferably the two Grooves are arranged offset towards opposite narrow edges (S) of the pieces of wood.
Description
[0015] An exemplary embodiment of the invention is described below with reference to the drawing. In these:
[0016] FIG. 1 shows a schematic plan view of a device for laying a longitudinal layer and a transverse layer, each to the side of a press;
[0017] FIG. 2 shows a side view with a circular saw for making a saw groove and feeding a string element to the lamellae or boards;
[0018] FIG. 3 shows a board layer in a schematic perspective view;
[0019] FIG. 4 shows a schematic cross section through three CLT layers;
[0020] FIG. 5 shows a schematic perspective view of a wood part connection in board shape;
[0021] FIG. 6 shows an end view of a piece of wood with two obliquely running grooves; and
[0022] FIG. 7 shows an end view of a board section with offset grooves.
[0023] FIG. 1 shows a schematic plan view of a press in which several longitudinal layers L and transverse layers Q are manufactured to form a cross-laminated timber element (CLT).
[0024] The longitudinal layer L shown above has a length of 14 m and (in the wall version) a height of over 3 m, for instance. The same applies to the transverse layer Q shown below, which consists of a large number of boards 1 (compare FIG. 3) is compiled (so-called. “Lay”). According the laying direction different by 90° for instance, the laying tables arranged on the right and left of the press have a stop rail 9 offset at right angles (see also FIG. 3). After the respective longitudinal layer L and transverse layer Q have been put together, they are transferred to the press in layers, as indicated by the arched arrows, and after the glue has been applied (glue application only on the main surface H; compare FIG. 3) pressed into a CLT element. Other joining methods are also possible. This ensures a secure connection of the individual slats with boards of adjacent individual layers, with cutouts 5 for windows or doors also being arranged congruently.
[0025] What is presently essential is the introduction of string elements 2 in the transverse direction to the board course, preferably in the form of beadings. The term “transverse direction” is not limited to 90° here, but can be e.g. also be 80° to the board direction (compare FIG. 3). In the longitudinal position L, eight such beadings 2a (compare also FIG. 4) are provided here, namely in each case at the end regions and adjacent to the three openings 5. In the transverse position Q, “only” four string elements 2 are required, namely again at the end areas (here above and below) and along the windows. The beading 2a continues through the door shown here on the right in order to ensure the connection to the right end area, namely a certain pre-tension between the individual slats. Thus, the individual boards are pre-fixed at their narrow edges and thus the individual layer is held together as a package or component so that it can be transported into the press (here in the middle) for pressing (e.g. each with a side roller conveyor). The beading 2a extending through the door is then cut off on the construction site.
[0026] FIG. 2 shows the laying process with four boards 1 here on a laying table T, onto which a further lamella 1 (here on the right on a conveyor belt F) is shifted intermittently by means of a feed slide Z. The incoming lamella 1 is pressurized here by conveyor belts (arrow D) and pushed against the boards 1 that have already been laid, so that the respective gap S at the narrow edges is minimized. A feed 6 (here with a plurality of rollers) and a supply roll 4 for the wire-shaped string element 2, in particular a beading 2a, is provided above the thus prepared package of laid boards 1. The (a few centimeters) protruding beginning of the beading 2a (see. also FIG. 1, with the protruding ends of the string element 2 or FIG. 5 with the protrusion U) can be seen here on the left end board after passing through a pressure roller 6a. For a better hold on the end area of the transversely elastic, largely tensile-strength beading 2a can also be folded slightly, in particular in the form of a metal wire, preferably made of relatively soft aluminum or copper, in order to prevent affecting subsequent processing. Projections of the string element 2 can thus be easily removed with a side cutter after pressing or on the construction site.
[0027] The beading 2a is preferably pressed into a groove 3 (compare FIGS. 3 and 4), which is simultaneously cut (or milled) as the boards 1 pass under the feeder 6. This takes place with boards 1 that are tightly joined to one another, that is to say with a small gap at the side edges S, so that the string element 2 is tensioned or pre-fixed and holds the slats together on and after the pressure roller 6a. The saw 7 thus cuts a groove 3 which runs (largely) transversely to the main direction of the boards and in which the beading 2a is clamped with pretension in order to hold the pack of boards of one layer together securely. The saw 7 is here equipped with a vacuum system A in order to keep the created groove 3 clean.
[0028] In FIG. 3, the course of the groove 3 in the transverse direction at the end regions of the boards 1 is drawn in dash-dot lines, also schematically the laying table T with a stop rail 9. Only four lamellas are shown here, with approximately thirty (long) boards being required for a longitudinal layer L, depending on the dimensions, and around a hundred (shorter) boards 1 for a transverse position. The groove 3 can also be incorporated at an angle other than 90°, as indicated by double-dot-dash lines 3, in order to improve the cohesion of the board package of an individual layer.
[0029] FIG. 4 shows a cross section through a CLT element with only three layers here, although seven (or more) individual layers are usually used for outer walls. The beading 2a pressed into the grooves 3 can be seen here, which avoids a gaping in the gap area between the boards 1 via clamping forces and/or friction in the groove 3 and/or minimizes it under axial prestress. For further anchoring in the groove 3, it can also be oriented at an oblique angle, as is indicated in the right-hand area of FIG. 4.
[0030] In the longitudinal layer L at the top here, the grooves 3 point downwards in order to offer the CLT element a smooth outer surface. For this purpose, for instance the package shown in FIG. 3 can be turned “upside down”, or the saw 7 (or an end mill) can be arranged below the laying table T (with appropriate slots) and the line element 2 (beading 2a) can be fed from below. Since the chips can then fall down, a vacuuming can (largely) be dispensed with.
[0031] FIG. 5 shows a schematic view of a wood part connection for forming a long board from several pieces of wood 1a (short slats or board sections). The pieces of wood 1a can, for instance have a minimum length of 30 cm, depending on the cutting and sorting, board sections of 1 meter or more can be used. Thus, in FIG. 1, the left piece of wood 1a is for instance 40 cm long, the following at a transverse joint 1 for instance 50 cm and the subsequent board section for instance is 90 cm. In order to configure a board 1 with that of 14 m in length, for instance (for a glue binder or a longitudinal layer L), for instance 20 pieces of wood (of different lengths) are joined together at 19 transverse joints. The transverse joint 1b is designed as a butt joint (possibly with a glue joint) so that complex finger joints can be dispensed with. According to the innovation, at least one groove 3 (here two grooves 3 and 3′) is incorporated into the main surface H, into which an elongated string element 2 is inserted, in particular with prestress in the form of a beading 2a. Hereby the board sections are pressed together at their transverse joints 1b, so that a safe pre-fixing of the individual board sections is achieved.
[0032] What is essential here is the introduction of string elements 2 in the longitudinal direction LR (along the board), preferably in the form of beadings 2a (so-called beading cord) with axial pretension. Presently, two such beadings 2a (compare also FIGS. 2 and 3) are provided. By pressing the beading 2a into the groove 3 (or Groove 3′) there is a certain pre-tension between the individual pieces of wood 1a. Thus, the individual board sections are pre-fixed at their transverse joints 1b and thus the board 1 held together as a single layer or component so as to, for instance to be transported to a press (for instance each with a side roller conveyor). Since the beading 2a running through the board 1 has an end protrusion U, the board assembled in the longitudinal direction L can also be gripped well manually (or a gripping device) and for instance be transported by two workers or a conveyor system. The same applies to robots, the joined board preferably being turned by 180° so that the string elements 2 are at the bottom and thus avoid sagging.
[0033] FIG. 6 shows a face view of a board section, the two grooves 3, 3′ here inclined at an angle of approximately 30° to the main surface H to improve the anchoring of the string element 2 in the respective groove. For this purpose, the beading 2a can also have a structured surface, in particular in the form of a plastic thread (e.g. made of nylon in the manner of a fishing line) or metal wire, preferably made of relatively soft aluminum or copper, so as not to impair subsequent processing. The protrusions U of the string element 2 can be easily removed after pressing or on the construction site with a side cutter or scissors.
[0034] The beading 2a is preferably pressed into the groove (s) 3, 3 with a pressure roller, which is cut (or milled) simultaneously as the board sections pass through. The string element 2 can have a slightly larger diameter (e.g. 6 mm) than the groove width (e.g. B. manufactured with 5 mm). This takes place with pieces of wood 1a closely joined together, i.e. with a slight transverse joint 1b, so that the string element 2, which is tensile in the longitudinal direction L but still slightly elastic, is axially braced or pre-fixed and holds the board sections together. The string element 2 is therefore (in contrast to wooden strips or wooden dowels) clamped with pretension in the groove 3 serving as a beading strip, in order to hold the board sections together practically without impact.
[0035] In FIG. 7, the grooves 3, 3′on opposite main surfaces H of the board sections are shown. Here too, the grooves 3, 3′are incorporated at an angle other than 90° relative to the main surface H in order to improve the clamping effect of the pressed-in beading 2a and thus the cohesion of the board sections in the longitudinal direction L. The tensile beading 2a pressed into the grooves 3, 3 avoids or minimizes a gaping between a respective cross joint 1b between the board sections due to its axial clamping forces or friction in the respective groove 3, 3′. The lower string element 2 (beading 2a, as is usually the case as rolled goods, so-called. Beading cord available) to the left side edge S can also be fed from below, whereby the saw (or a milling cutter) to form the groove 3′also dips into the board sections from below.
