Manufacturing method for laminated lumber

Abstract

To manufacture laminated lumber with no knots appearing on a laminated surface, while suppressing an increase in manufacturing cost.SOLUTION: The manufacturing method of laminated lumber 200 comprises a selection step of selecting a sawn board 100 with no knots 150 on a short side surface 110, and a laminate step of stacking a long side surface 102 of the sawn board 100 with no knots 150 on the short side surface 110 to produce the laminated lumber 200.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for manufacturing glued laminated timber.

Background Art

[0002] Patent Document 1 discloses a technique related to a method for detecting knots in a wood material such as a veneer or a sawn timber cut from a log of wood. In this prior art, a wood material is photographed by photographing means, the circularity of an image is calculated from the image of the wood material photographed by image processing means, and a portion having a large calculated circularity is detected as a knot. Further, an image of a knot portion is cut out from the image of the wood material photographed by the image processing means, a portion cut out from the color space of each pixel in the cut-out portion with a predetermined threshold value is defined as a blackened portion, and a portion having a large ratio of the number of pixels of the blackened portion to the number of pixels of the cut-out knot portion is determined as a dead knot.

[0003] Patent Document 2 discloses a technique related to a method for inspecting wood for detecting defective portions due to discoloration in a wood material such as a veneer or a sawn timber cut from a log of wood. In this prior art, color photography is performed for each wood material by photographing means, the chromaticity distribution of a color image photographed by the photographing means is obtained for each wood material, the cumulative frequency distribution of the obtained chromaticity distribution is compared with the cumulative frequency distribution of a normal wood material determined in advance, and a wood material showing a distribution in which the cumulative frequency distribution of the obtained chromaticity distribution is separated from the cumulative frequency distribution of the normal wood material by a predetermined value or more is defined as a wood material to be sorted.

[0004] Patent Document 3 discloses a technique related to a wood defect detection device, particularly a wood defect detection device for detecting defects on the surface of a thin sheet-like veneer to be laminated on a plywood or on the surface of a plywood laminated with veneers. In this prior art, it comprises illumination means for illuminating the surface of an inspection wood material being transported at a predetermined speed, imaging means for imaging the surface of the inspection wood material illuminated by the illumination means, and processing means for detecting defects on the surface of the inspection wood material based on the image imaged by the imaging means. The illumination means irradiates light in a wavelength range of 420 nm to 530 nm onto the inspection surface of the inspection wood material, and the processing means extracts a defective portion based on the luminance in the imaged image.

[0005] Patent Document 4 discloses a technique related to a wood appearance inspection apparatus that inspects various defects such as knots, cracks, and discoloration on the surface of wood using an image of the wood surface captured. In this prior art, a grayscale image captured by a line sensor camera is input into an image processing apparatus. The primary candidate extraction unit binarizes the grayscale image of the wood surface divided into a plurality of inspection target regions captured by the line sensor camera, and extracts primary defect candidate regions. The secondary candidate extraction unit binarizes the grayscale image with a second threshold value set to separate the wood grain and defects for the inspection target region of interest, and extracts secondary defect candidate regions. The defect extraction unit discriminates defects using the difference between the grayscale values of the pixels included in the secondary defect candidate region and the grayscale values of the pixels around the secondary defect candidate region in the inspection target region including the secondary defect candidate region.

[0006] Patent Document 5 discloses a technique related to an inspection apparatus for a laminated wood material. In this prior art, the inspection apparatus for a laminated wood material includes a surface inspection apparatus that uses vertical irradiation light and oblique irradiation light irradiated on the surface of the laminated wood material, and an end inspection apparatus that uses end irradiation light irradiated on the end of the laminated wood material.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0008] In the JAS for sawn timber, knotless, upper-small-knot and small-knot are defined by the number of knots on the long-side surface of the crossbar. When manufacturing laminated wood by laminating crossbars with upper-small-knots or small-knots, which are cheaper than knotless ones, the manufacturing cost of the laminated wood can be suppressed, but knots appear on the laminated surface. When manufacturing laminated wood by laminating only knotless crossbars, which are more expensive than upper-small-knots and small-knots, knots do not appear on the laminated surface of the laminated wood, so it is excellent in design, but the manufacturing cost of the laminated wood increases.

[0009] In view of the above facts, an object of the present invention is to manufacture laminated wood in which knots do not appear on the laminated surface while suppressing an increase in manufacturing cost.

Means for Solving the Problems

[0010] The first aspect is a method for manufacturing laminated wood, comprising a sorting step of sorting crossbars having no knots on the short-side surface, and a laminating step of laminating the long-side surfaces of the crossbars having no knots on the short-side surface to produce laminated wood.

[0011] According to the method for manufacturing laminated wood of the first aspect, by sorting and laminating crossbars having no knots on the short-side surface even if there are knots on the long-side surface, it is possible to suppress an increase in manufacturing cost while preventing knots from appearing on the laminated surface formed by the short-side surface, and to manufacture laminated wood with excellent design.

[0012] The second aspect is the method for manufacturing laminated wood according to the first aspect, further comprising a longitudinal splicing step of cutting and removing the portion having knots on the short-side surface, longitudinally splicing crossbars having no knots on the short-side surface, and making them into crossbars having no knots on the short-side surface.

[0013] According to the method for manufacturing laminated wood of the second aspect, even if there are knots on the short-side surface, by cutting and removing the portion having knots on the short-side surface, longitudinally splicing crossbars having no knots on the short-side surface, and making them into crossbars having no knots on the short-side surface, it is possible to suppress an increase in manufacturing cost while preventing knots from appearing on the laminated surface formed by the short-side surface, and to manufacture laminated wood with excellent design.

[0014] The third aspect is a method for manufacturing a laminated wood material, comprising a sorting step of sorting into a first splitting board having no knots on the short side surfaces of both sides, a second splitting board having no knots only on the short side surface of one side, and a third splitting board having knots on the short side surfaces of both sides, and a laminating step of laminating the long side surfaces of the first splitting board to produce a first laminated wood material, laminating the long side surfaces of the second splitting board to produce a second laminated wood material, and laminating the long side surfaces of the third splitting board to produce a third laminated wood material.

[0015] According to the method for manufacturing a laminated wood material of the third aspect, it is sorted into a first splitting board having no knots on the short side surfaces of both sides even if there are knots on the long side surface, a second splitting board having no knots only on the short side surface of one side, and a third splitting board having knots on the short side surfaces of both sides, and the long side surfaces are laminated respectively to manufacture a first laminated wood material, a second laminated wood material, and a third laminated wood material. Therefore, a first laminated wood material in which no knots appear on the laminated surface is manufactured while suppressing an increase in manufacturing cost, and a second laminated wood material having few knots on the laminated surface and a third laminated wood material having many knots on the laminated surface are manufactured.

[0016] The fourth aspect is the method for manufacturing a laminated wood material according to the third aspect, comprising a longitudinal splicing step of cutting and removing a portion having the knot on the short side surface of the second splitting board or the third splitting board, and longitudinally splicing splitting boards having no knots on the short side surfaces of both sides to obtain the first splitting board.

[0017] According to the method for manufacturing a laminated wood material of the fourth aspect, by cutting and removing a portion having a knot on the short side surface of the second splitting board and the third splitting board, and longitudinally splicing splitting boards having no knots on the short side surface, the first splitting board is obtained.

[0018] The fifth aspect is that the sorting step includes: a step of obtaining an X-direction profile of luminance values in the X direction in the grayscale image of the long-side surface, and a Y-direction profile of luminance values in the Y direction orthogonal to the X direction of the long-side surface; a step of obtaining dark pixels where the luminance value is equal to or less than a threshold value in both the X-direction profile and the Y-direction profile; a step of determining, as the knots, those other than the dark pixels where the aspect ratio of a rectangular region where the dark pixels are located is greater than a set value, or those other than where the ratio of the number of pixels in the rectangular region to the number of dark pixels is greater than a set value; and a step of determining whether or not the knots are within a predetermined distance from the short-side surface on the long-side surface. The method for manufacturing a laminated wood according to the first aspect or the third aspect includes these steps.

[0019] According to the method for manufacturing a laminated wood of the fifth aspect, it is possible to manufacture a laminated wood in which no knots appear on the laminated surface while suppressing an increase in manufacturing cost.

Advantages of the Invention

[0020] According to the present invention, compared with the case of manufacturing a laminated wood in which no knots appear on the laminated surface using only knot-free sawn boards without knots on the long-side surface defined by the Timber JAS, it is possible to manufacture a laminated wood in which no knots appear on the laminated surface while suppressing an increase in manufacturing cost.

Brief Description of the Drawings

[0021]

Figure 1

Figure 2

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Figure 7

Figure 8

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Figure 10

Figure 11

Figure 12

Figure 13

Embodiments for Carrying Out the Invention

[0022] <Embodiment> The manufacturing method of the laminated wood of the present embodiment will be described with reference to the drawings.

[0023] In each drawing, the longitudinal direction of the rectangular long side surface 102 of the laminated board 100 described later is defined as the X direction and indicated by arrow X, the width direction is defined as the Y direction and indicated by arrow Y, and the thickness direction of the laminated board 100 is defined as the Z direction and indicated by arrow Z. Also, the origin is set as G.

[0024] Note that each drawing is only schematically shown. Also, the dimensions, ratios, etc. of each element shown in the drawings do not necessarily match the actual ones. Also, the dimensions, ratios, number, etc. of each element do not necessarily match even among multiple drawings. Also, in this embodiment, descriptions of configurations not directly related to the present invention and well-known configurations may be omitted or simplified.

[0025] [Structure] First, the structure of the glued laminated timber manufactured by the method for manufacturing glued laminated timber of this embodiment will be described.

[0026] As shown in FIGS. 1 and 2, the glued laminated timber 200 is a wood material in which the long side surfaces 102 of a plurality of sawn boards 100 are laminated and bonded with an adhesive. On the laminated surface 210 of the glued laminated timber 200, the short side surfaces 110 of the respective sawn boards 100 are exposed.

[0027] Note that a "sawn board" is a natural wood cut into a plate shape. The "short side surface" in this embodiment is the short side surface in the cross section in the width direction of the sawn board, and the "long side surface" is the long side surface in the cross section in the width direction of the sawn board. Also, in this embodiment, the "short side surface" is a "quarter-sawn surface" cut parallel or substantially parallel to the annual rings (fiber direction), and the "long side surface" is a "plain-sawn surface" where the annual rings look like mountains (see FIG. 8), but it is not limited thereto.

[0028] Also, the glued laminated timber 200 of this embodiment is a structural glued laminated timber used for beams and columns of buildings such as buildings. Therefore, those with a total length of 3 m or more in the longitudinal direction (X direction) of the sawn board 100 are used. For the sawn board 100, woods such as cedar, spruce, cypress, Japanese larch, Korean pine, and Dahurian larch are used. Note that it is not limited thereto.

[0029] As described above, the longitudinal direction of the long side surface 102 of the rectangular shape in the cutting board 100 is defined as the X direction and indicated by the arrow X, the width direction is defined as the Y direction and indicated by the arrow Y, and the thickness direction of the cutting board 100 is defined as the Z direction and indicated by the arrow Z. Also, the origin is set as G. The ends (short side surfaces 110) in the width direction (Y direction) of the long side surface 102 of the cutting board 100 and the vicinity of the ends are defined as side portions 104 and 106. Note that the "vicinity" refers to a predetermined distance from the end (short side surface 110). In this embodiment, the side portions 104 and 106 are defined as the range within 20 mm from the side, but it is not limited to this.

[0030] [Overview of the manufacturing method] First, an example of the overall overview of the manufacturing method of laminated wood will be described. Note that the following manufacturing method is just an example and is not limited thereto.

[0031] (1) Sawing process The cutting board 100 (see FIGS. 2 and 8) is sawn from the logs of the felled natural wood. (2) Drying process The cutting board 100 is dried. (3) Grading process The cutting board 100 is passed through a grading machine to measure the deflection, and the cutting board 100 is divided into a plurality of groups (grade classification) according to the magnitude of the deflection amount.

[0032] (4) Longitudinal jointing process As shown in FIG. 3, for each grade, a removal portion 190 having a defect site 192 that has a large impact on the strength reduction such as cracks, rot, and large dead knots in the cutting board 100 is cut and removed. The shortened cutting board after removal is adhesively joined with a finger joint 194 for longitudinal joining to form a long cutting board 100.

[0033] Note that at this time, a wood scanner capable of automatically detecting the defect site 192 inside the cutting board 100 at high speed may be used to discover the defect site 192, and then a device for automatically removing the defect site 192 may be introduced.

[0034] Further, in the case where the longitudinal jointing process in the present embodiment is after the sorting process described later, this process can also be a process in which the second splitting plate 100B and the third splitting plate 100C are used as the first splitting plate 100A.

[0035] (5) Adhesive application process Evenly apply an adhesive to the surface of the splitting plate 100 conveyed by a belt conveyor or the like. (6) Laminating, compressing, and adhesive curing process Cure the adhesive in a state where a plurality of splitting plates 100 are laminated and compressed. (7) Wood grain processing After maintaining the compressed state for a predetermined time, for example, one day, release the compression pressure and clean the surface of the glued laminated wood 200 soiled with the adhesive or the like.

[0036] [Sorting process] Next, the sorting process of the method for manufacturing the glued laminated wood of the present embodiment will be described.

[0037] Note that the sorting process may be performed anywhere after the (1) sawing and splitting process and before the (5) adhesive application process.

[0038] Also, in the sorting process, using the sorting system 320 described later, the splitting plate 100 is sorted into a first splitting plate 100A without knots 150 on both side portions 104A and 106A in the long side surface 102 in FIG. 4(A), a second splitting plate 100B without knots 150 on only one of the side portions 104B or 106B, and a third splitting plate 100C with knots 150 on both side portions 104C and 106C. After sorting, mark them with different colors, symbols, etc. so that the first splitting plate 100A, the second splitting plate 100B, and the third splitting plate 100C can be easily distinguished.

[0039] Note that the splitting plate before sorting is referred to as the splitting plate 100, and the splitting plates after sorting are referred to as the first splitting plate 100A, the second splitting plate 100B, and the third splitting plate 100C. However, when it is not necessary to distinguish and explain even after sorting, it will be described as the splitting plate 100.

[0040] The first folding plate 100A has no node 150 on the short side surface 110A (see Fig. 4(D)), the second folding plate 100B has no node 150 only on one short side surface 110B (see Fig. 4(E)), and the third folding plate 100C has nodes 150 on both short side surfaces 110C (see Fig. 4(F)).

[0041] Here, as described above, in this embodiment, selection is made based on the presence or absence of the node 150 in the side portions 104 and 106 within 20 mm from the short side surface 110 (end) of the long side surface 102 as viewed in the plate thickness direction. This is because when only the node 150 applied to the short side surface 110 is targeted, even if there is a node 150 that is not applied to the short side surface 110, its shape may change in the plate thickness direction and it may be exposed on the short side surface 110.

[0042] Also, after the selection process, the short side surface 110 may be cut, and as a result, the node 150 may be exposed later. In order to reliably prevent these, selection is made based on the presence or absence of the node 150 in the side portions 104 and 106 within 20 mm from the short side surface 110. Therefore, at the time of selection, there may be cases where the node 150 is not exposed on the short side surface 110B of the second folding plate 100B and the short side surface 110C of the third folding plate 100C.

[0043] Therefore, even if the node 150 is not exposed on the short side surfaces 110B and 110C, if it is within a predetermined distance, in this embodiment, within 20 mm, from the short side surfaces 110B and 110C, it is assumed that there is a node 150 on the short side surfaces 110B and 110C. That is, whether there is a node 150 on the short side surface 110 is not determined by the presence or absence of exposure to the short side surface 110, but by whether there is a node 150 within a predetermined distance from the short side surface 110.

[0044] [Longitudinal splicing process] As described above, in the longitudinal splicing process, as shown in Fig. 3, the defective portion 192 of the folding plate 100 is cut and removed at the removal portion 190, and the shortened folding plate after removal is adhesively bonded with the finger joint 194 and longitudinally joined to form a long folding plate 100.

[0045] When the above sorting process is carried out after this longitudinal splicing process, the veneer 100 including the longitudinally spliced veneer 100 is sorted into a first veneer 100A, a second veneer 100B, and a third veneer 100C.

[0046] When the above sorting process is carried out before this longitudinal splicing process, and when the knots 150 at the side portions 104B, 104C, 106B, 106C in the second veneer 100B and the third veneer 100C are only in the removal portion 190, when the removal portion 190 is removed, the veneer after longitudinal splicing becomes the first veneer 100A without the knots 150 at the side portions 104A, 106A.

[0047] In addition, for example, when recording the X-direction positions of the knots 150 at the side portions 104, 106 in the second veneer 100B and the third veneer 100C during sorting and comparing them with the X-direction position of the removal portion 190, it can be determined that the knots 150 at the side portions 104, 106 disappear due to the removal of the removal portion 190.

[0048] Also, even if there is no defect site 192, the portions of the knots 150 at the side portions 104, 106 in the second veneer 100B and the third veneer 100C may be removed as the removal portion 190 and longitudinally spliced to form the first veneer 100A.

[0049] [Glulam] FIG. 4(D) shows a first glulam 200A made by laminating only the first veneer 100A, FIG. 4(E) shows a second glulam 200B made by laminating only the second veneer 100B, and FIG. 4(F) shows a third glulam 200C made by laminating only the third veneer 100C. When there is no need to distinguish and describe the first glulam 200A, the second glulam 200B, and the third glulam 200C, they are described as the glulam 200.

[0050] The first glulam 200A is a glulam with excellent design properties having no knots 150 on the lamination surface 210A. The second glulam 200B has fewer knots 150 on the lamination surface 210B than the lamination surface 210C of the third glulam 200C and has higher design properties than the third glulam 200C.

[0051] Note that the laminated surface 210B of the second laminated lumber 200B, which has a large number of knots 150 only on one short side surface 110B, may have more knots 150 than the laminated surface 210C of the third laminated lumber 200C, which has a small number of knots 150 on both short side surfaces 110C.

[0052] However, basically, the appearance ratio of the knots 150 on the long side surface 102 of the laminated lumber 100 is in the order of the second laminated lumber 100B and the third laminated lumber 100C. Therefore, it is considered extremely rare for the number of appearances of the knots 150 on the laminated surface 210B of the second laminated lumber 200B to be more than that on the laminated surface 210C of the third laminated lumber 200C.

[0053] [Decorative lumber] Next, a fire-resistant wooden column as an example of a decorative lumber using the laminated lumber 200 will be described. Note that this example will describe an example of manufacturing a fire-resistant wooden column using only the first laminated lumber 200A, but it is not limited thereto. Also, this fire-resistant wooden column is an example, and the laminated lumber 200 can be used for other members such as beams and slabs in addition to columns.

[0054] As shown in FIG. 5, in the fire-resistant wooden column 500 of the present embodiment, the laminated surface 210A where the knots 150 (see FIG. 1 etc.) of the first laminated lumber 200A do not appear is the outer peripheral surface.

[0055] As shown in FIG. 6, the central portion of the fire-resistant wooden column 500 is composed of a concrete-filled steel tube column (hereinafter referred to as "CFT column") 10 inside. The CFT column 10 includes a steel tube 12 and concrete 14 filled inside the steel tube 12. A plurality of corner base materials 20 are arranged around the steel tube 12.

[0056] (Corner base material) A plurality of corner base materials 20 are arranged around the steel pipe 12 along the material axis direction (vertical direction) of the steel pipe 12. Each corner base material 20 is formed of a lightweight steel frame or the like having an L-shaped cross section and is arranged outside each corner of the steel pipe 12. The corner base materials 20 are arranged with the material axis direction of the steel pipe 12 as the longitudinal direction and extend from the column base portion to the column head portion of the steel pipe 12. Further, the upper and lower ends of the corner base materials 20 are supported by runners (not shown).

[0057] The corner base material 20 has a pair of flange portions 20A. The pair of flange portions 20A are bent along the corners of the wood fireproof covering material 30 composed of the first laminated wood 200A. The ends 30E and 40E of the wood fireproof covering material 30 and the metal plate 40 are attached to the pair of flange portions 20A.

[0058] (Wood fireproof covering material) A plurality (four in this embodiment) of wood fireproof covering materials 30 composed of the first laminated wood 200A are arranged so as to surround the steel pipe 12. More specifically, the plurality of wood fireproof covering materials 30 are arranged in a rectangular frame shape surrounding the steel pipe 12 when viewed from the material axis direction of the steel pipe 12, and fireproofly cover the steel pipe 12. Each wood fireproof covering material 30 is arranged with a space from the outer surface of the steel pipe 12. The space functions as a heat insulating layer (heat insulating space).

[0059] The wood fireproof covering material 30 functions as a fireproof covering material. Specifically, the wood fireproof covering material 30 functions as a charring layer for fireproofly covering the steel pipe 12. The charring layer is a layer that suppresses the intrusion of fire heat to the steel pipe 12 side by burning during a fire to form a carbonized layer (heat insulating layer).

[0060] When viewed from the axial direction of the steel pipe 12, the adjacent wood-based fireproof covering materials 30 are arranged along directions that are substantially orthogonal to each other. Also, the ends 30E of the adjacent wood-based fireproof covering materials 30 are abutted in an L-shape when viewed from the axial direction of the steel pipe 12, forming a corner 30C. Further, a joint 32 is formed between the ends 30E of the adjacent wood-based fireproof covering materials 30. The ends 30E of these wood-based fireproof covering materials 30 are attached to the corner base material 20 via a metal plate 40.

[0061] (Metal plate) The metal plate 40 is formed of a steel plate, an iron plate, etc. with high thermal conductivity. Also, the metal plate 40 is sized substantially the same as the wood-based fireproof covering material 30 and is overlapped over substantially the entire inner surface 30A of the wood-based fireproof covering material 30. The metal plate 40 is attached (screwed) to a portion (hereinafter referred to as "general portion 30M") that is off from the end 30E of the wood-based fireproof covering material 30 by a plurality of screws 42 from the side of the steel pipe 12. Also, the metal plate 40 is arranged to face the outer surface (side surface) of the steel pipe 12 in a state of being attached to the inner surface 30A of the wood-based fireproof covering material 30.

[0062] The wood-based fireproof covering material 30 and the metal plate 40 are arranged over the outer surface of the flange portion 20A of the adjacent corner base materials 20, and both ends 30E, 40E on both sides thereof are attached (screwed) to the flange portion 20A by a plurality of screws 34. The plurality of screws 34 are arranged at intervals in the longitudinal direction of the flange portion 20A. In this embodiment, a countersink 36 for the screw 34 is formed on the outer surface 30B of the wood-based fireproof covering material 30. However, the countersink 36 can be omitted as appropriate.

[0063] [Sorting system] Next, an example of a sorting system for sorting the grinding plate 100 into a first grinding plate 100A (FIG. 4(A)), a second grinding plate 100B (FIG. 4(B)), and a third grinding plate 100C (FIG. 4(C)) will be described.

[0064] FIG. 7 is a block diagram showing the hardware configuration of the sorting system 320. The sorting system 320 includes a CPU (Central Processing Unit) 321, a ROM (Read Only Memory) 322, a RAM (Random Access Memory) 323, a storage 324, an imaging unit 325, a user interface 327, and a communication interface 328. Each component is communicably connected to each other via a bus 329.

[0065] The CPU 321 is a central processing unit that executes various programs and controls each part. That is, the CPU 321 reads a program from the ROM 322 or the storage 324 and executes the program using the RAM 323 as a working area. The CPU 321 performs various controls and various arithmetic processes according to the program recorded in the ROM 322 or the storage 324. In the present embodiment, the ROM 322 or the storage 324 stores a sorting program for sorting the first scrap plate 100A (FIG. 4(A)), the second scrap plate 100B (FIG. 4(B)), and the third scrap plate 100C (FIG. 4(C)) from the image of the long side surface 102 of the scrap plate 100 imaged by the imaging unit 325.

[0066] The ROM 322 stores various programs and various data. The RAM 323 temporarily stores a program or data as a working area. The storage 324 is composed of an HDD (Hard Disk Drive) or an SSD (Solid State Drive) or the like and stores various programs and various data including an operating system.

[0067] The imaging unit 325 images a color image of the long side surface 102 of the scrap plate 100 conveyed by a belt conveyor or the like. The imaging unit 325 includes an optical system (such as a lens) and an image sensor or the like.

[0068] The user interface 327 is an interface when an operator uses the sorting system 320. The user interface 327 includes, for example, a liquid crystal display with a touch panel enabling touch operations by the operator, a mouse, a keyboard, and the like.

[0069] The communication interface 328 is an interface for the sorting system 320 to communicate with other devices. For example, standards such as Ethernet (registered trademark), FDDI, and Wi-Fi (registered trademark) are used.

[0070] Here, in the sorting system 320 of the present embodiment, imaging is performed by the dedicated imaging unit 325, but it is not limited thereto. Imaging images of imaging devices installed for other purposes may be input. For example, in the above-described longitudinal splicing process, when an existing wood scanner capable of automatically detecting the defective part 192 inside the splicing board 100 at high speed is introduced, the imaging image captured by the wood scanner may be input. That is, the sorting system 320 may not have the imaging unit 325.

[0071] [Sorting Method] Next, an example of the sorting method performed by the sorting system 320 will be described.

[0072] FIG. 8 is an imaging image obtained by the imaging unit 325 of the sorting system 320 imaging the long side surface 102 of the splicing board 100.

[0073] First, the sorting system 320 captures an image and converts the captured color image into an 8-bit grayscale image to obtain a grayscale image. An X-direction profile (see FIG. 11) of the luminance value in the X direction and a Y-direction profile (see FIG. 10) of the luminance value in the Y direction in the grayscale image are obtained.

[0074] Here, assuming that the number of pixels in the X direction is Hpix (pixels) and the number of pixels in the Y direction is Wpix (pixels), since there is a profile for each pixel, there are W X-direction profiles and H Y-direction profiles.

[0075] Next, dark pixels whose luminance values are equal to or less than the threshold value are obtained in both the X-direction profile and the Y-direction profile. From another perspective, the region of the logical product where the luminance values are equal to or less than the threshold value is obtained in both the X-direction profile and the Y-direction profile, and this region is defined as the dark pixels. Then, among the dark pixels, those remaining after excluding elongated objects such as thick annual rings and fibers are defined as knot candidates.

[0076] Next, the color information of the pixels of the knot candidates detected from the color image is obtained to determine whether they are knots. Specifically, it is determined whether the color of the knot candidates is the color of the knots. The "color of the knots" is, for example, generally between light brown and almost black.

[0077] Then, the first pulling plate 100A (FIG. 4(A)), the second pulling plate 100B (FIG. 4(B)), and the third pulling plate 100C (FIG. 4(C)) are sorted according to the presence or absence of the knots 150 at the side portions 104 and 106 of the long side surface 102.

[0078] In this embodiment, in the sorting by the knots 150 on the long side surface 102 of the pulling plate 100, the determination and sorting are performed using only one long side surface 102. Generally, the plate thickness of the pulling plate 100 used for the glued laminated timber 200 is thin, and the knots 150 appear at substantially the same positions on both sides of the long side surface 102. Therefore, there is no problem in performing the determination and sorting using only one long side surface 102. However, in cases where the accuracy is to be improved or the pulling plate 100 has a large plate thickness, the determination may be performed using both long side surfaces 102. When performing the determination using both long side surfaces 102, even if there are no knots 150 at the side portions 104 and 106 on one long side surface 102, if there are knots 150 on the other long side surface 102, it is determined that there are knots 150 at the side portions 104 and 106.

[0079] (Processing of the sorting method) Next, an example of the processing flow of the sorting method performed by the sorting system 320 will be described with reference to the flowchart of FIG. 13. Note that the sorting process is performed by the CPU 321, which is an example of the processor in FIG. 7, reading the sorting program from the ROM 322 or the storage 324, expanding it in the RAM 323, and executing it.

[0080] As shown in FIG. 13, the CPU 321 captures an image of the long side surface 102 of the drawing plate 100 by the imaging unit 325 (step S101). The CPU 321 converts the captured color image into an 8-bit grayscale image to obtain a grayscale image (step S102). The CPU 321 obtains an X-direction profile of the luminance values in the X direction (see FIG. 11) and a Y-direction profile of the luminance values in the Y direction (see FIG. 10) in the grayscale image (step S103).

[0081] The CPU 321 obtains dark pixels whose luminance values are equal to or less than the threshold value in both the X-direction profile and the Y-direction profile (step S104). The CPU 321 uses, as node candidates, those remaining after excluding the long and narrow ones among the dark pixels (step S105). The CPU 321 acquires the color information of the pixels of the node candidates and retains only the nodes 150 (step S106).

[0082] The CPU 321 determines whether or not there are no nodes 150 in both side portions 104 and 106 (step S107). If there are no nodes 150 (Yes), the process proceeds to step S108. The CPU 321 sets it as the first drawing plate 100A (step S108).

[0083] If there are nodes 150 in step S107 (No), the process proceeds to step S109. The CPU 321 determines whether or not there are nodes 150 in both side portions 104 and 106 (step S109). If there are nodes 150 (Yes), the process proceeds to step S110. The CPU 321 sets it as the third drawing plate 100C (step S110).

[0084] If there are no nodes 150 in step S109 (No), the process proceeds to step S111. The CPU 321 sets it as the second drawing plate 100B (step S111).

[0085] (Dark pixels) Next, an example of a method for obtaining dark pixels from the X-direction profile of the luminance values in the X direction and the Y-direction profile of the luminance values in the Y direction in the grayscale image will be specifically described.

[0086] FIG. 10(A) is the Y-direction profile when the pixel position in the X direction shown in FIG. 9 is X1, and FIG. 10(B) is the Y-direction profile when the pixel position in the X direction shown in FIG. 9 is X2. SY in each figure is the threshold value of the luminance value of the Y-direction profile.

[0087] FIG. 11(A) is the X-direction profile when the pixel position in the Y direction shown in FIG. 9 is Y1, and FIG. 11(B) is the X-direction profile when the pixel position in the Y direction shown in FIG. 9 is Y2. SX in each figure is the threshold value of the luminance value of the X-direction profile. Note that the threshold values for both SX and SY are set to 150. Also, generally, luminance values in the range of 160 to 190 are the grained portions.

[0088] Here, in this example, the threshold values for both SX and SY are set to 150, but it is not limited to this. The threshold values do not have to be the same in the X direction and the Y direction. Also, the threshold values do not have to be constants, and they may be values derived by numerical calculations. Examples of numerical calculations include values such as 80% of the average value of each profile or the minimum value of each profile.

[0089] The portions below the threshold value in each figure are the nodes 150 and the central fiber 159 on the long side surface 102 of the grinding plate 100 in FIG. 8.

[0090] (Node candidate) Next, an example of a method for setting candidates for nodes by excluding long, dark pixels such as thick annual rings and fibers will be described.

[0091] In this embodiment, those that meet either of the following (A) and (B) are considered to be long (not nodes 150).

[0092] (A) Those in which the aspect ratio (≈ ellipticity) of the rectangular region in the X direction and the Y direction where there are dark pixels is larger than the set value (B) Those in which the ratio of the number of pixels in the rectangular region in the X direction and the Y direction where there are dark pixels to the number of dark pixels is larger than the set value

[0093] Next, the above will be described by taking the dark pixels 90A in Fig. 12(A), the dark pixels 90B in Fig. 12(B), and the dark pixels 90C in Fig. 12(C) as examples.

[0094] Let the aspect ratio (≈ ellipticity) of the rectangular region be EL. Note that EL is the value obtained by dividing the longer (greater) one of the length (number of pixels) in the X direction and the length (number of pixels) in the Y direction of the rectangular region by the shorter (lesser) one of the length (number of pixels) in the X direction and the length (number of pixels) in the Y direction. Also, let the ratio of the number of pixels in the rectangular region to the number of pixels in the dark pixels be ES. Then, the set value of EL is 1.8, and the set value of ES is 1.5. Note that these set values are just examples and are not limited thereto.

[0095] For the dark pixel 90A in Fig. 12(A), the length (number of pixels) in the X direction of the rectangular region is 8, the length (number of pixels) in the Y direction is 9, and the number of pixels in the dark pixel 90A is 16. Therefore,

[0096] EL = 9 / 8 = 1.125 ES = (8×9) / 16 = 4.5

[0097] As a result, since both EL and ES are larger than the set values, it is determined that it is not slender and not the section 150.

[0098] For the dark pixel 90B in Fig. 12(B), the length (number of pixels) in the X direction of the rectangular region is 8, the length (number of pixels) in the Y direction is 3, and the number of pixels in the dark pixel 90B is 17. Therefore,

[0099] EL = 8 / 3 ≈ 2.667 ES = (8×3) / 17 ≈ 1.412

[0100] As a result, since ES is less than or equal to the set value, but EL is larger than the set value, it is determined that it is slender and not the section 150.

[0101] For the dark pixel 90C in Fig. 12(C), the length (number of pixels) in the X direction of the rectangular region is 4, the length (number of pixels) in the Y direction is 4, and the number of pixels in the dark pixel 90B is 12. Therefore,

[0102] EL = 4 / 4 = 1.0 ES = (4×4) / 12 ≒ 1.333

[0103] It becomes like this. Therefore, since both EL and ES are below the set values, it is determined that it is not slender and it is determined to be the node 150.

[0104] (Verification with color information) Next, an example of a method for obtaining the color information of the pixel of the node candidate detected from the color image and determining whether it is a node will be described.

[0105] In this embodiment, when the values of each of RGB of the color of the pixel of the node candidate are smaller than the respective set values, it is determined to be a node.

[0106] Specifically, if R of RGB is r, G is g, and B is b, and the set value of R is Tr, the set value of G is Tg, and the set value of B is Tb,

[0107] r < Tr g < Tg b < Tb

[0108] when it is determined to be a node. In this embodiment, Tr is 100, Tg is 55, and Tb is 70, but it is not limited to these. Note that this method is an example and is not limited to this. For example, if the color difference between the node candidate and the reference color in the L*a*b* color system is within a predetermined range, it may be determined to be a node.

[0109] Note that the step of obtaining the color information of the pixel of the node candidate detected from the color image and determining whether it is a node is not essential. The node candidate may be directly determined to be the node 150.

[0110] <Function> Next, the function of this embodiment will be described.

[0111] Select the first bending board 100A without knots on the short side surfaces 110A on both sides, the second bending board 100B without knots only on one short side surface 110B, and the third bending board 100C with knots on the short side surfaces 110C on both sides, and stack the long side surfaces 102A, 102B, and 102C respectively to manufacture the first laminated wood 200A, the second laminated wood 200B, and the third laminated wood 200C.

[0112] Therefore, it is possible to manufacture the first laminated wood 200A in which no knot 150 appears on the lamination surface 210A while suppressing an increase in manufacturing cost. Furthermore, it is possible to easily manufacture the second laminated wood 200B with fewer knots 150 on the lamination surface 210B and the third laminated wood 200C with more knots 150 on the lamination surface 210C than the second laminated wood 200B probabilistically.

[0113] Explaining from another perspective, by selecting the presence or absence of the knots 150 on the short side surface 110, it is possible to easily manufacture the first laminated wood 200A, the second laminated wood 200B, and the third laminated wood 200C with different grades of design properties.

[0114] Also, cut and remove the removal portions 190 with knots 150 on the short side surfaces 110B and 110C of the second bending board 100B and the third bending board 100C, and longitudinally join the bending boards without knots on the short side surface 110 to obtain the first bending board 100A. Therefore, a large number of the first laminated woods 200A in which no knot 150 appears on the lamination surface 210A can be manufactured.

[0115] Also, in the sorting process, among the dark pixels whose luminance value is equal to or less than the threshold value using the grayscale image of the long side surface 102, those excluding the long and narrow ones are determined as knot candidates or knots 150. Therefore, it is possible to select the presence or absence of the knots 150 on the short side surface 110 without using an expensive wood scanner or image analysis software. Note that an expensive wood scanner or image analysis software may also be used.

[0116] <Others> Note that the present invention is not limited to the above-described embodiment.

[0117] For example, in the above embodiment, the first bending plate 100A has no joints 150 on both side portions 104A and 106A of the long side surface 102, the second bending plate 100B has no joint 150 on only one of the side portions 104B or 106B, and the third bending plate 100C has joints 150 on both side portions 104C and 106C, but it is not limited thereto. For example, the short side surface 110 of the bending plate 100 may be imaged and sorted based on whether there is a joint 150 in the captured image.

[0118] Also, in this embodiment, the bending plate 100 is sorted by the sorting system 320, but it is not limited thereto. By setting and operating an existing wood scanner that can automatically detect the defective part 192 inside the bending plate 100 at high speed, a first bending plate 100A having no joint 150 on both short side surfaces 110A of both sides, a second bending plate 100B having no joint 150 on only one short side surface 110B of one side, and a third bending plate 100C having joints 150 on both short side surfaces 110C of both sides can be sorted. If possible, an existing wood scanner may be used. Alternatively, the joint 150 may be machine-learned by artificial intelligence to sort the first bending plate 100A, the second bending plate 100B, and the third bending plate 100C.

[0119] Also, in the above embodiment, the bending plates are sorted into a first bending plate 100A having no joint 150 on both short side surfaces 110A of both sides, a second bending plate 100B having no joint 150 on only one short side surface 110B of one side, and a third bending plate 100C having joints 150 on both short side surfaces 110C of both sides, but it is not limited thereto. The bending plates may be sorted into a first bending plate 100A having no joint 150 on both short side surfaces 110A of both sides and other bending plates 100.

[0120] In the above embodiment, the second bending plates 100B having no joint 150 on only one short side surface 110B are randomly laminated to manufacture the second glued laminated timber 200B, but it is not limited thereto. The short side surfaces 110B having no joint 150 may be aligned and laminated to manufacture a second glued laminated timber 200B with excellent design properties having no joint 150 on one laminated surface 210B.

[0121] In the above-described embodiment, the sorting process that the CPU 321 reads and executes software (program) may be executed by various processors other than the CPU. Examples of the processor in this case include PLDs (Programmable Logic Devices) such as FPGAs (Field-Programmable Gate Arrays) whose circuit configurations can be changed after manufacturing, and dedicated electric circuits such as ASICs (Application Specific Integrated Circuits) having circuit configurations designed specifically to execute specific processes. Further, the sorting process may be executed by one of these various processors, or may be executed by a combination of two or more processors of the same type or different types (for example, a combination of a plurality of FPGAs, and a combination of a CPU and an FPGA, etc.). More specifically, the hardware structure of these various processors is an electric circuit combining circuit elements such as semiconductor elements.

[0122] Also, part or all of the sorting steps performed by the sorting system 320 may be manually performed by an operator.

[0123] Furthermore, the present invention can be implemented in various modes without departing from the gist thereof. A plurality of embodiments and modifications can be implemented in combination as appropriate.

Description of Reference Numerals

[0124] 90A Dark pixel 90B Dark pixel 90C Dark pixel 100 Kneading plate 100A First kneading plate 100B Second kneading plate 100C Third kneading plate 102 Long side surface 102A Long side surface 102B Long side surface 102C Long side surface 104 Side portion 104A Side portion 104B Side portion 104C Side portion Side part 106A Side part 106B Side part 106C Short side surface 110 Short side surface 110A Short side surface 110B Short side surface 110C Node 150 Removal part 190 Defect part 192 Finger joint 194 Glued laminated timber 200 First glued laminated timber 200A Second glued laminated timber 200B Third glued laminated timber 200C Laminated surface 210 Laminated surface 210A Laminated surface 210B Laminated surface 210C Sorting system 321

Claims

1. A sorting step of sorting veneer boards without knots on the short side surfaces, An assembling step of laminating the long side surfaces of the veneer boards without knots on the short side surfaces to produce a glued laminated timber, A method for manufacturing a glued laminated timber comprising the above steps.

2. The method for manufacturing a glued laminated timber according to Claim 1, further comprising a longitudinal splicing step of cutting and removing the portions with knots on the short side surfaces, longitudinally splicing the veneer boards without knots on the short side surfaces to form veneer boards without knots on the short side surfaces. The method for manufacturing a glued laminated timber according to Claim 1.

3. A sorting step of sorting into a first veneer board without knots on the short side surfaces of both sides, a second veneer board without knots only on the short side surface of one side, and a third veneer board with knots on the short side surfaces of both sides, An assembling step of laminating the long side surfaces of the first veneer board to produce a first glued laminated timber, laminating the long side surfaces of the second veneer board to produce a second glued laminated timber, and laminating the long side surfaces of the third veneer board to produce a third glued laminated timber, A method for manufacturing a glued laminated timber comprising the above steps.

4. The method for manufacturing a glued laminated timber according to Claim 3, further comprising a longitudinal splicing step of cutting and removing the portions with knots on the short side surfaces of the second veneer board or the third veneer board, longitudinally splicing the veneer boards without knots on the short side surfaces of both sides to form the first veneer board. The method for manufacturing a glued laminated timber according to Claim 3.

5. The sorting step includes: A step of obtaining an X-direction profile of the luminance values in the X direction in the grayscale image of the long side surface and a Y-direction profile of the luminance values in the Y direction orthogonal to the X direction of the long side surface, A step of obtaining dark pixels where the luminance value is below a threshold in both the X-direction profile and the Y-direction profile, A step of determining, among the dark pixels, those other than those where the aspect ratio of the rectangular region with the dark pixels is greater than a set value or those other than those where the ratio of the number of pixels in the rectangular region to the number of dark pixels is greater than a set value as knots, A step of determining whether the knots are within a predetermined distance from the short side surface on the long side surface, and having the above steps. The method for manufacturing a glued laminated timber according to Claim 1 or Claim 3.

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