EP2703137A2 - Method of sawing of wood lamellae and the manufacturing of a multi-layer product - Google Patents

Abstract

The method involves sawing slats directly from wood i.e. round split log (1), along a height direction using a belt saw, where the slats exhibit unchanged width relative to the round split log. The slats are sawed with an angle of about 45-80 degree between a transport direction of the wood and a movement direction of a saw blade during a sawing process. The slats are stacked with spacers and dried by warm air, where the spacers exhibit a strip form. The spacers are perforated transverse to a longitudinal direction of the strip form.

Description

The present invention relates to a method and a plant for sawing wood lamellae from starting woods. In this case, a lamella means a relatively thin board, with a maximum thickness of 40 mm, preferably a maximum of 30 mm. Such lamellae can be used for various applications, for example for the production of multilayer flat materials, in particular so-called solid wood panels in which, for example, three or five layers of lamellae are formed and adhesively bonded to one another. Depending on the thickness and other designs, such solid wood panels may be of interest for the furniture industry, for interior fittings or even for the production of entire building walls.

The lamella production takes place in specialized enterprises of the wood-processing industry, which subdivide boards purchased by sawmills (with larger strengths) with the help of circular saws at least with regard to the strength. For example, five slats of correspondingly lower thickness can be sawn from one board.

The present invention is based on the problem of specifying an economical method for sawing slats an associated system.

This problem is solved by a method for sawing slats of unedged starting wood, in which the slats are sawed off with a band saw directly from the output woods along the direction of growth
and by a plant designed for this purpose with a transport device for gripping untrimmed outgoing lumber on its natural outer surface and feeding the starting lumber to a band saw, which is designed for sawing lamellae directly from the starting lumbers.

Preferred embodiments are given in the dependent claims (and also refer to the problem solution presented above with regard to the disclosure) and are explained in detail below in addition to the invention in its most general form. The description always refers to both claim categories.

The invention is characterized by the unedged starting wood used and sawed off with a band saw directly from fins. "Immediate" or "direct" means here that in the sawing process a sawed-off piece is a lamella and does not have to be further subdivided into a lamella in the following. It is therefore not a question of sawing unedged outgoing timber between formats, in particular boards with greater thickness than slats, and then subdividing them separately.

Ungebaumte starting woods are in the context of this invention, those having at least one natural outer surface and preferably up to at most two or more preferably at most one sawn outer surface exclusively natural outer surfaces. A natural outer surface is an outer surface of the plant with bark or debarking, but no sawn surface. In the natural outer surface so the original outer surface of the trunk or other round logs can be recognized.

Specifically, this means that either round timbers (which includes trunk lengths, ie the direction of growth for subdivided logs) or simply split logs are preferably sawn. A simple division of a round wood (ie a trunk or a comparable piece of wood with circumferential natural outer surface) corresponds to a simple sawing the length (ie along the direction of growth), with approximately symmetrical section in profile approximately semi-circular so-called "crescents" arise. On sawing these and whole strains, the invention is preferred.

If now unedged starting woods are used, then you save yourself by the usual Zusägen of boards (as a standard commercial intermediate product) incurred cutting losses and also the corresponding intermediate step. Usually, namely, the unedged starting wood in the sawmill cut into boards and these boards then transported to another wood-processing operation, which saws from the boards lamellae. With regard to the handling of the boards when sawing the slats that is also quite advantageous because four flat outer surfaces as contact surfaces, sliding surfaces and reference surfaces are available. Also, the requirements on the sawing depth are lower. However, a trunk profile can only be subdivided into boards at the expense of clear cutting. Because of the smaller format of the slats, however, significantly more slats can be sawed out of the same trunk profile. In addition, it saves the division into two sawing operations and also the usual in the art transport by truck or train.

Incidentally, in the prior art regularly undried logs are sawn into boards and dried the boards before sawing the slats. In contrast to the saw settings during board sawing, drying shrinkage losses occur, so that an optimal adaptation of the desired lamella thicknesses to the board formats can be accomplished poorly. This shrinkage processes are not precisely predictable and thus the distribution of the dried boards in the lamella is usually not reliable. Accordingly, surcharges must be taken into account for safety and fall to further waste and sawing costs.

Incidentally, the use of unedged starting wood also allows for the consideration of relatively small roundwood formats, which are not considered for the production of boards at all and were previously used only for the production of low-value products such as packaging or wooden pallets or for energy.

In this sense, the inventor proposes to "skip" the more or less standardized or in any case usual intermediate "board" in the slat production and saws directly slats. Boards can then be sawn for other applications where the board format is actually used as such, or further processed into other formats (other than slats). Because the commercial intermediate "board" is of course in the art by far not only the lamellar production but also many other purposes. This is precisely why it has become established as a standard starting material for sawmills.

The subdivision of the round timbers in crescents has the advantage in the context of the invention of providing at least one contact surface for the subsequent lamellar sawing process. But you can also run undivided round timbers along natural outer surfaces on contact surfaces (see below for keyword "trimming") and cut lamellae directly from the roundwood. Thus, starting from one side of the approximately circular cross-section, the cross-sectional profile would be ablated to the other side. If initially, preferably with a band saw, crescents or similar simply divided round logs are used as starting lumber, then already created sawing surfaces, from which starting the lamellae can be sawed off (but not necessarily). This band saw for easy parts of the round logs is preferably the band saw for sawing the slats immediately ahead, so located in the sense of editing upstream directly in front of it and belongs to the same overall system.

Preferably, in the context of this invention undried starting woods, such as crescents, sawed. The fins can be dried quite quickly and the inventor has found that the sawing of undried wood leads, for example in knotholes to significantly fewer outbreaks and thus ultimately better wood quality or a smaller number of repairs. Under undried wood is here preferably understood as having at least 15%, 20% or, in the most favorable case, 30% residual moisture.

Furthermore, it is preferred that the lamellae have a width which is unchanged relative to the original round lumbers, that is to say they have not been subdivided with regard to their width direction (perpendicular to the direction of growth and to the thickness direction, ie the smallest length extension of the lamella). This is for many applications, in particular those described below, the cheapest, cheapest in terms of waste and the least connecting points generating way to further processed product.

A preferred embodiment of the invention provides a pulling section of the band saw, in which the band saw blade forms an oblique angle to the transport direction and in this sense (with its component of motion projected on the transport direction) along with the transport direction of the output woods. A preferred angular range for the angle between the transport direction of the output woods and the transport direction of the saw blade is between 45 ° and 80 °. As lower limit are increasingly preferred 50 ° and 55 ° and 60 °. As upper limits are increasingly preferred 75 ° and 70 °.

A further preferred embodiment of the invention, but as a precaution also independent of the features of claim 1, so the direct sawing of the unedged Ausgangsshölzer to slats with a band saw is disclosed (the formation of corresponding claims reserved), is the conical trimming of sawn Slats to better take into account the natural conical habit of the roundwoods. Preferably, this can be done by applying the unedged output edge to a corresponding guide, so that the trimming at least approximately follows the growth habit. In principle, however, any angled edging (relative to the direction of growth) should be included, which, in terms of its sign (the direction of slimming), is closer to the natural growth habit than a trimming parallel to the growth direction, as in the prior art. For not quite straight trimming, the mean value is decisive.

Of course, the conical trimming of the lamellae concerns the trimming cut along a natural outer surface, wherein, as already mentioned, the latter preferably serves as a leading edge. Accordingly, in the method according to the invention it is certainly possible for blades with only one conically edged edge or without a conically edged edge to occur, namely when the complete round wood width is not present in the blade. It may well be desirable to limit the slat width or to normalize it within a certain tolerance range. However, the processing of so-called "falling widths", so the full occurring in the original round timber widths (of course, less trimming) is preferred.

As already explained at the beginning, the sawn lamellae can be dried particularly quickly. Spacers are preferably used to in lamella stacks sufficient spaces for hot air drying create. The spacers may be perforated, such as in the form of perforated aluminum strips. Preferably, they are perforated in both transverse directions (with respect to the longitudinal direction of the strip), as shown in more detail in the embodiment.

The trimming can be done before or after drying. The trimming preferably takes place before and after the drying, and in a particularly preferred manner as mentioned above conical (and again also independent of the features of claim 1). The Besäumschritt before drying can thereby facilitate the stacking process, because irregular edge profiles are sawn off and thus more effective stacking is possible. The Besäumvorgang after drying can specify the slightly thrown by the drying process edge. In none of the Besäumschritte steps, it is imperative that the edged edge is precisely straight; Rather, it may be sufficient to substantially eliminate the irregularities existing / caused by the untrimmed edge or the drying process and to produce an edge suitable for further processing.

If the lamellae have at least one conical edge, that is to say an edge chamfered obliquely relative to the direction of growth, an order alternating with respect to the conicity is preferred in the further processing into flat products. This concerns z. B. gluing the slats on other products, eg. B. fillers of multi-layer products or other carriers. In particular, however, the lamellae can be glued together along the edges, in particular in order then to be glued as surface product to another layer. Above all, the invention is directed to the production of so-called "solid wood panels", namely multi-layer glued sheet products from just such slats. The lamellae can be glued with respect to adjacent layers crossed fiber and growth direction; preferably at least three layers are present.

"Alternating" means preferably, alternating from single lamellae to single lamellae, thus reversing the direction of growth. Especially with small Konizitätswinkeln this is not mandatory and can z. B. also two adjacent lamellae be the same orientation and then again two vice versa.

It has already been explained that the conicity angles can follow the natural outer surface by serving as a contact surface or by otherwise losing as little as possible by the trimming cut by means of angle adaptation. Then the conicity angles are statistically distributed. In many cases, the alternating sequence alone, due to this statistical distribution, can ensure that there are not too great deviations between the desired main fiber direction in the desired layer direction and the fiber direction actually present in each lamella or between the desired main fiber direction and the edge profile.

According to a further aspect, the multilayer products according to the invention can be edged on their edges and glued together so that, at least in one dimension, a quasi-continuous format is created. In many cases, shocks produced by these shanks are not really troublesome in the superficial appearance, wherein preferably the impacts in the visible layers run approximately perpendicular to the fiber direction and accordingly at center layers preferably along the fiber direction. Thus, not only gluing along the conical edged edges are made in the visible cover layers but also vertical gluing, at least if appropriate lengths of the sheet material are desired. Individual lengths can then be tailored individually to the order of the "endless format" created by the shots, depending on the individual customer commission, or in other ways. This also eliminates the otherwise occurring in the production of multi-layer products in standard lengths blend in the form of the difference between these standard lengths and an individually desired length.

A system according to the invention is preferably characterized in that the first transport device (in the sense of the time sequence of the processing steps) for gripping undivided round timbers, ie logs, is designed on its natural outer surface. This transport device can then feed the logs to a saw for sharing, especially for sharing in crescents. The split round logs offer at least a straight contact surface and therefore do not necessarily require special measures during further processing. In particular, the crescents lying on or along the sawing surface and continuously supplied to the band saw or bands for slat cutting.

Figur 1

zeigt eine Übersichtsdarstellung einer erfindungsgemäßen Anlage in Perspektive von oben.

Figur 2 und 3

zeigen schematische Darstellungen zum Lamellensägen.

Figur 4

zeigt eine schematische Darstellung zum Besäumen der Lamellen.

Figuren 5 und 6

zeigen schematische Darstellungen zum Trocknen der Lamellen.

Figur 7

zeigt eine schematische Darstellung zur Herstellung eines Flächenerzeugnisses aus den Lamellen.

In the following, the invention will be explained in more detail with reference to an exemplary embodiment which is described in more detail with reference to the figures and whose details are of importance for both categories of claim. The details may also be essential to the invention in combinations other than those shown.

FIG. 1

shows an overview of a system according to the invention in perspective from above.

FIGS. 2 and 3

show schematic views of the saws.

FIG. 4

shows a schematic representation for trimming the slats.

FIGS. 5 and 6

show schematic illustrations for drying the slats.

FIG. 7

shows a schematic representation for producing a surface product from the slats.

FIG. 1 shows an overall view of a plant according to the invention in perspective from above. In an area at the top right, individual of the growth direction are cut to truncated logs 1 (trunks of 3 m) via an unspecified inclined ramp of (with respect FIG. 1 ) are promoted down to the top and then in relation to FIG. 1 debarked from right to left of spiked wide rollers and fed to a first band saw 2. The band saw 2 divides the logs 1 approximately centrally, vertically and longitudinally into crescents 3. The logs are thereby gripped on their round natural outer surface.

On the way to the first Vertikalbandsäge 2 can be seen in FIG. 1 a circle. This circle symbolizes the radius of action of a home user, which ensures an alternating sequence of the trunks with regard to the orientation of the braid and head (thinner or thicker end). This facilitates the later described alternating series of conical slats. The Turning of the trunks takes place about a vertical axis, the two trunk ends together approximately describe the drawn circle with a diameter of about 3 m.

Behind the first band saw 2, the generated half moons 3 are then again a piece transverse to their longitudinal direction (in FIG. 1 down) transported and then supplied with upwardly facing natural outer surface four in principle similar second band saw 4. The band saws 4 are in FIG. 1 drawn as elongated rectangles, wherein the saw band circulates approximately to these rectangles. It can be seen that the rectangles are at an angle of 65 ° to the transport direction (horizontally in FIG. 1 ) stand. Accordingly, the cutting plane of these band saws 4 is horizontal (in the plane of the FIG. 1 ), wherein the direction of movement of the band saw blade forms an angle of 65 ° in the intersection of the angular position of the rectangles corresponding to the transport direction and is tilted with respect to the vertical orientation by 25 °. In this case, the projected on the transport direction component of the saw blade movement direction is the same direction to the transport direction of the crescents 3, ie in FIG. 1 from right to left (so-called pulling cut).

The bandsaw pair 4 arranged at the same height with respect to the transport direction of the crescents 3 saws off a first lamella from a respective crescent 3 and the band saw pair 4 of the same crescents 3 following the direction of transport descend a further lamella.

The crescents 3 each pass first through a band saw 4 of the first pair, then are slightly offset inwardly (towards the center of the band saw assembly) and pass through one of the band saws 4 of the second pair. Behind them, they are transported inwards and, as indicated in the drawing, transported against the transport direction between the Bandsägepaaren 4 back forward again, and then re-enter one of the band saws of the first pair. The crescents 3 are thus recirculated to one of the two sides of the pair arrangement of band saws 4, until they are completely sawed to lamellae and a last remainder piece. The remaining piece is chopped up in a manner not shown. The vertical line pair in FIG. 1 suggests, that the chopped remainders of roundwood processing are removed from the plant area (in FIG. 1 to the top). They can be used as fuel.

FIG. 2 shows a highly schematic representation of a round wood profile of a trunk 1 with a central saw cut 5 of the band saw 2 and parallel saw cuts 6 of the band saw 4. It can be clearly seen that the remaining pieces 7 make up a minimal share of the original round wood profile and thus a waste minimized slat production , If boards had been sawed beforehand from the roundwood profile, because of the given widths, significantly larger residual pieces 7 (similar shape) and additional remnants would result, which would be due to the straight edged edges of the boards.

FIG. 3 symbolizes the saw geometry of the band saws 4. Here, the saw band is shown in sections and is symbolic of the entire band saw. With 3 a crescent is drawn, which moves along its longitudinal direction, as the arrow shows. There is an angle of 65 ° between this direction of movement and the saw blade 4. This sawing plane is horizontal.

FIG. 1 shows at 8 a transverse conveyor, the sawed slats, which at this point in FIG. 1 denoted by 9, receives and with respect to FIG. 1 upwards and actually horizontally transported sideways. As a result, they are fed to a trimming saw 10, in which the in FIG. 2 recognizable natural outer surface of the slats serves as a leading edge and slides along a bearing edge. The circular saw trimmed accordingly angled to the growth direction on one side. The unilaterally edged slats 9 are then trimmed by a second Besäumkreissäge 10 'on the other side, in a mirror image. Thus, the completely trimmed lamella is slightly trapezoidal, so has two angled to the direction of growth and as a result of this angled position converging towards each other long side edges, which is referred to here as "conical trimmed". The term "conical" refers ultimately to the three-dimensional growth form of the trunk itself, which is thinner in relation to the tree above than below.

FIG. 4 illustrates the saw geometry and the second Besäumsäge 10 ', in which case the circular saw blade is shown representative and designated 10'. It is parallel and at a distance to a contact device 11, along which the blade 9 is guided with a natural outer edge. This outer edge is drawn throughout and dashed to offset parallel not trimmed Besäumlinie. On the opposite side of the lamella 9, the already edged outer edge is drawn continuously and the natural outer edge no longer present here is dashed. The taper of the cut and the irregularities and of course the length-width ratio of the blade 9 are exaggerated.

The finished trimmed lamellae 9 with, for example, 5 mm to 6 mm thickness are then stacked in a device 12 (next to which a person is shown for clarification of the scales). In this case, they lie with respect to their edged edges slightly spaced in a plane next to each other and are the levels of aluminum spacers, namely flat long slats with vertical and horizontal communicating ventilation holes, separated from each other. The slat-shaped spacers run perpendicular to the slat longitudinal direction.

FIG. 5 shows some fins 9 which are separated by corresponding spacers 25. FIG. 6 shows a single spacer laterally and from above, namely a lath-shaped perforated aluminum strip 25. The holes shown are continuous and penetrate the aluminum strip 25 in both transverse directions to provide for a particularly good ventilation.

The stacks are constructed in the stacking device 12 on rail cars, which along in FIG. 1 vertically extending rails 13 and in FIG. 1 horizontally extending rails 14 can be moved. Left of the rails 13 is in FIG. 1 to see a trolley warehouse and above, so on the second Besäumsäge 10 'and to the left thereof, a warehouse with corresponding pallets and spacers.

To clarify: The two warehouses are located on the ground floor of the hall and the already explained elements 2 to 10 'on the first floor. In particular, therefore, the Besäumsägen 10 and 10 'above the spacer bearing. The logs 1 are transported on the right side along an oblique transport up to the first floor and when stacked in the stacker 12, the fins are moved down from this first floor.

A finished lamella stack is moved along the rails 13 so that it is in relation to FIG. 1 left in front of an elongated drying hall 15 on this associated rails 14 can be added. Drying in the drying hall is carried out by circulating warm air, whereby the humid warm air is released into the environment at intervals. The hitherto undried slats are brought here to a degree of drying of about 8% relative humidity.

At the in FIG. 1 Right end of the drying hall 15, the rail car with the lamella stacks out and up (that is, from the exit of the drying hall 15 from side to the left) proceed and brought over a definitely marked rail 14 back to the rails 13. They can be stored there (as well as before drying) in the carriage storage and then come to an implied destacking means 16. The unstacked fins are then by two other Besäumkreissäge 17 and 17 'again and only marginally trimmed to pass through the Drying incurred distortions of the Besäumsägen 10 and 10 'produced edges to straighten. Of course, the re-trimmed edges are substantially conical in the same way as the previous ones because the previous edges serve as a guide and guide.

From the second Besäumsäge 17 'from the lamellae 9 are then supplied to a here only roughly indicated plant area 18 in which the lamellae with regard to their quality machine with a camera and an electronic image analysis and possibly double check also visually (by people) checked and in to sorted into four quality levels. In a following plant area 19, the lamellae are then alternately in direct succession (that is, with the direction of growth reversed from neighbor to neighbor) to the edging edges glued to each other. The resulting surface product is still single-layered and typically has (in the finished state) dimensions of 1 250 mm (lamella length) by 3 000 to 6 000 mm in length (lamellae).

Here, the non-conical edges of the slats can be glued, so that the still single-layer surface product in the appropriate direction beyond the slat length, ie, for example, with a slat length of about 3 000 mm by simply gluing together along the original face corresponding edges a surface product of 6 000 mm is created.

These surface products are fed via transport means 20 a rotator 21 and brought from there into a summarily designated 22 hot press. There, three of these plates are glued surface-wide under pressure and heat, the lamellae sorted at 18 in the best quality form the top layer on the visible side, the second best quality the top layer on the opposite side and the third quality the intermediate layer. If four quality levels exist, the worst is discarded.

In the hot press 22 are thereby used for the outer layers surface products with running in the future longitudinal direction of fiber direction, so here so the conically edged edges are also approximately along. For the middle layer, sheet products having transverse fiber direction and corresponding orientation of the tapered edges are used (for a five-layered product, this would apply to layers 2 and 4 and the fiber orientation of the middle layer would correspond to cover layers). If the hot press 22 can process a multiple of the lamella length, it may either be expedient to produce a corresponding multiple of the lamella length in the preceding edge-bonding step (as already mentioned) by gluing together on the face side. But you can also juxtapose two such single-ply surface products in the corresponding layers and put on each other butt, because the absence of the individual Kantenleimverbindung after production of the surface gluing no longer plays a significant role.

The finished glued three-layer solid wood panels are then in the sense of a tongue and groove connection at its shorter side edge (ie transverse to the fiber direction of the thick layers) and glued together, creating a virtual endless format. This can then be cut to individual customer requirements and stacked to commissions. Incidentally, the finished three-layer solid wood panels are again trimmed along the longer side edge.

The FIGS. 7a and b show conically edged lamellae 9 in a sequence in an alternating sequence, namely a middle layer 26 of the solid wood panels produced in Figure 7a and a topsheet 27 in FIG FIG. 7b , The conicity angles and their fluctuations are exaggerated. The right-angled ends should symbolize the commission-specific lengthening of the virtual endless format. the length I is therefore largely arbitrary. 28 indicates busied connection points. The reference numerals I and 28 therefore refer to the finished solid wood panel.

Incidentally, the devices designated by 23 permit a separate supply of single-layer surface products for the gluing to three-layer solid wood panels, in particular of cover layers from other production. If desired, different wood qualities can be used here, and the lamellae from roundwood processing, for example, can only be used for the middle classes. If, in such cases, the previously described lamellar production ejects too many fins, a portion of this production can be discharged and temporarily stored or otherwise processed via a plant area summarily designated 24.

Claims (14)

Method for sawing lamellae (9) from unedged starting lumbers (1, 3) and producing a multilayer product in which the lamellas (9) are sawed off from the starting lumbers along the direction of growth with a band saw (4) and
the lamellae (9) to a multilayer product glued (22) are characterized in that the lamellae (9) are not divided with respect to the original round timbers (1) in terms of their width direction, the width direction perpendicular to the direction of growth and to the direction with the smallest longitudinal extent of the lamella (9). A method according to claim 1, wherein the starting woods (3) are simply divided logs (1). Method according to claim 2, in which the simply divided round timbers are simply divided by a band saw (2), which band saw (2) of the band saw (4) is immediately ahead of the starting timbers (3) for sawing off the laminations (9). Method according to one of the preceding claims, in which the starting woods (3) are undried. Method according to one of the preceding claims, in which the lamellae (9) are sawed at an angle between the transport direction of the starting lumbers (3) during sawing and the transport direction of the saw blade during sawing between 45 ° and 80 °, wherein the direction in the transport direction of the starting lumber ( 3) projected component of the speed of the saw blade with the transport of the starting lumber runs along. Method according to one of the preceding claims, in which the lamellae (9) are conically trimmed (10, 10 ', 17, 17'), preferably by placing the unedged starting edges on a guide (11). Method according to one of the preceding claims, in which the lamellae (9) are dried with spacers (25) stacked by hot air. The method of claim 7, wherein the spacers (25) have a strip shape and are perforated transversely to the longitudinal direction of the strip shape, preferably perforated in both transverse directions. Method according to claims 6 and 7, also in connection with claim 9, in which the lamellae (9) are trimmed conically before (10, 10 ') and after (17, 17') the drying. Method according to claim 6, also in conjunction with one of claims 8 to 10, in which the lamellae (9) are glued (19) in an alternating sequence with successive edges produced by the conical trimming, to form a surface product (26), and preferably along the edges. Method according to one of the preceding claims, in which the lamellae (9) are trimmed (17, 17 ') and the edges produced thereby are glued together (19). Method according to one of the preceding claims, in which the lamellae (9) are glued to form an at least three-ply solid wood panel. Method according to one of the preceding claims, in which the multi-layer products are placed on side edges and glued together (28), in particular to an individually definable (I) endless format (26, 27). Use of a band saw (4) for sawing lamellae (9) from unedged starting lumber (3) directly from the starting lumbers along the direction of growth, in particular according to one of claims 2 to 13.

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