Stack for drying original board and method for drying original board using the same

Abstract

In the conventional method for drying a raw board using battens, batten marks remained on the dried raw board, leading to a significant deterioration in the marketability of the solid wood board after processing the raw board. 【Solution means】 When drying a raw board 1 sawn into boards from a log, a raw board drying batten 10 is arranged above and below the raw board 1 perpendicular to the longitudinal direction of the raw board 1. The raw board drying batten 10, when arranged between the raw boards 1, has, when viewed from the cross-sectional direction of the raw board 1, a joint portion 13 that joins both end regions 12 in the width direction of the wood surface 11 of the raw board 1, and a non-joint portion 15 that does not join the middle region 14 in the width direction of the wood surface 11 of the raw board 1, and a wood surface facing portion 16 having these, and a wood back facing portion 18 having a joint portion 19 that joins across the entire width region of the wood back 17 of the raw board 1.

Description

Technical Field

[0001] The present invention relates to a technique of a crossbar for drying a raw board disposed above and below the raw board perpendicular to the longitudinal direction of a long raw board when drying a raw board sawn into boards from a log of a log, and a method for drying a raw board using the crossbar for drying the raw board.

Background Art

[0002] In recent years, the use of solid wood boards cut from a single tree and used as they are without using chemical agents such as adhesives has been increasing.

[0003] Solid wood boards have excellent characteristics such as "less health damage to the body because adhesives and chemical agents are not used", "high humidity effect and comfortable indoor environment", "texture and quality of the wood itself can be enjoyed", "natural wood is less likely to cause rapid humidity changes indoors, and prevents moisture and dryness by absorbing and releasing moisture in the air", and "the more it is used, the heavier and more flavorful it becomes, and it is easy to repair".

[0004] Therefore, solid wood boards are widely used in applications such as "floors and walls of houses", "furniture such as tables, cabinets, and TV boards", and "structural materials such as columns". Known types of wood used as solid wood boards include cedar, cypress, oak, walnut, etc.

[0005] By the way, a drying process of drying a raw board of a solid wood board sawn from a log to a predetermined moisture content is essential to suppress shrinkage after construction. In that drying process, as shown in FIG. 1 (photo), a plurality of raw boards 1 with the board surfaces facing up and down are arranged horizontally side by side along the longitudinal direction, and the raw boards 1 are stacked in multiple layers while arranging crosspieces 2 at substantially equal intervals in the longitudinal direction of the raw boards 1. The crosspieces 2 are essential to create a passage for air necessary for drying between the upper and lower raw boards 1. A weight (not shown) is placed on the raw boards 1 stacked as shown in FIG. 1, and it becomes a solid wood board through a predetermined drying process.

[0006] However, a major problem occurs here. As shown in Fig. 2 (photo), darkening or lightening wood marks 3 remain on the parts where the battens 2 of the original board 1 had contact after the drying process. The wood marks 3 are considered to be caused by the extraction components undergoing concentration or chemical changes when moisture moves during the drying of the original board 1. The wood marks 3 penetrate not only the surface but also the deep part of the original board 1. Also, the wood marks 3 are amplified by the clear coating applied when used as a solid wood board.

[0007] Fig. 3 (photo) shows a floor 5 of a house where floorboards 4 completed by planer forming (planing) the original board 1 with wood marks 3 and applying clear coating are laid. The wood marks 3 are scattered irregularly on the surface of the floorboard 4. Thus, the aesthetics of the floor 5 using the solid wood board, which should enjoy a natural texture, are impaired by the wood marks 3. That is, the commercial value of the solid wood board is greatly impaired by the wood marks 3.

[0008] Therefore, a wood drying method for suppressing the occurrence of wood marks has been proposed. In Patent Document 1, a wood drying method is proposed in which a large number of parallel uneven strips intersecting the length direction are formed on the upper and lower surfaces of a square bar, and battens formed such that the width of the surface of each convex strip is 5 mm or less, preferably 3 mm or less, are interposed for drying. According to Patent Document 1, it is said that substantially no color tone pattern due to the battens is formed on the surface of the wood dried by this method.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0010] Since the lumber of Patent Document 1 has uneven stripes formed thereon, the convex stripe portions of the lumber will come into contact with the original board. Therefore, the contact surface pressure between the convex stripe portions of the lumber and the original board becomes even higher than the contact surface pressure in the case of ordinary lumber. Therefore, there remains a risk that lumber marks will occur on the portion of the original board that comes into contact with the convex stripe portions.

[0011] Therefore, the inventor of the present application focused on the fact that when the original board sawn from a log into planks dries, it always has the property of deforming into a shape with the center of the back surface convex. That is, the inventor invented a lumber for drying the original board that does not generate lumber marks by having a non-joint portion that does not join with the middle region in the width direction of the wood surface of the original board. Furthermore, a method for drying the original board using the lumber for drying the original board is proposed.

Means for Solving the Problems

[0012] The lumber for drying the original board according to the first invention is a lumber for drying the original board that is arranged above and below the original board perpendicular to the longitudinal direction of the original board when drying the original board sawn from a log into planks. The lumber for drying the original board has, in a state of being arranged between the original boards, as viewed from the cross-sectional direction of the original board, a wood surface facing portion having a joint portion that joins both end regions in the width direction of the wood surface of the original board and a non-joint portion that does not join with the middle region in the width direction of the wood surface of the original board, and a wood back facing portion having a joint portion that joins across the entire width region of the wood back of the original board.

[0013] In the lumber for drying the original board according to the first invention, since the middle region in the width direction of the wood surface of the original board does not join with the lumber for drying the original board, no lumber marks occur in the middle region in the width direction of the wood surface of the original board. Also, although the back surface of the original board joins with the wood back facing portion of the lumber for drying the original board, since the contact pressure is extremely low, no lumber marks occur in the middle region in the width direction of the wood back of the original board either. During drying, the original board tends to deform (warp) into a shape with the center of the back surface convex, but the deformation is restricted by the wood back facing portion of the lumber for drying the original board, and a straight plane is maintained.

[0014] The lumber for drying the original board according to the second invention is characterized in that the ratio of the length of the non-joint portion of the wood surface facing portion to the width dimension of the original board is in the range of 70% to 90%.

[0015] The crosspieces for drying the original board according to the second invention do not generate crosspiece marks on both the wood surface and the wood back in the range of 70% to 90% of the width dimension of the original board, so there is no practical problem with the appearance at all.

[0016] The crosspieces for drying the original board according to the third invention are characterized in that the non-joint part of the wood surface facing part is parallel to the joint part of the wood back facing part.

[0017] The crosspieces for drying the original board according to the third invention can easily form the wood surface facing part by simply shaving it into a shape slightly recessed from the joint part of the wood surface so as to be parallel to the joint part of the wood back facing part as the non-joint part of the wood surface facing part.

[0018] The crosspieces for drying the original board according to the fourth invention are characterized in that the material of the crosspieces for drying the original board is wood.

[0019] Since the material of the crosspieces for drying the original board according to the fourth invention is wood, it is possible to easily perform the forming process of the non-joint part of the wood surface facing part.

[0020] The method for drying the original board according to the fifth invention arranges a plurality of the original boards with the plate surfaces facing up and down horizontally side by side along the longitudinal direction, and further stacks them in multiple layers while arranging the crosspieces for drying the original board according to the first invention at equal intervals in the longitudinal direction of the original board, and after constructing an aggregate of the original boards with a weight placed on the upper part thereof, the aggregate of the original boards is naturally dried and then dried in a dryer through an artificial drying process, thereby drying the moisture content of the original board to a predetermined value or less.

[0021] According to the method for drying the original board according to the fifth invention, it is possible to dry the moisture content of the original board to a predetermined value or less without generating crosspiece marks.

Effect of the Invention

[0022] By using the crosspieces for drying the original board of the present invention, it is possible to dry the original board sawn from a round log into planks and make it into a solid board without remaining crosspiece marks.

[0023] Moreover, according to the method for drying a raw board of the present invention, it is similarly possible to dry a raw board sawn into planks from a log of a round timber and produce a solid board without remaining rail marks.

Brief Description of the Drawings

[0024]

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Best Mode for Carrying Out the Invention

[0025] FIG. 4 is an enlarged view of the main part seen from the cross-sectional direction of the board drying rail 10 according to the embodiment disposed above and below the original board 1 perpendicular to the longitudinal direction of the original board 1 when drying the original board 1 sawn from a log into a board. Note that, as an example in the embodiment, the dimensions of the original board 1 are a thickness dimension of 40 mm, a width dimension of 250 mm, and a longitudinal length of 4000 mm.

[0026] As shown in FIG. 4, in the state of being disposed between the original boards 1, the board drying rail 10 has a joining portion 13 that joins with both end regions 12 in the width direction of the wood surface 11 of the original board 1 when viewed from the cross-sectional direction of the original board 1. Further, the board drying rail 10 has a non-joining portion 15 that does not join with the middle region 14 in the width direction of the wood surface 11 of the original board 1. The board drying rail 10 according to the embodiment is configured with a wood surface facing portion 16 from the joining portion 13 and the non-joining portion 15. The left and right ends of the non-joining portion 15 are continuously connected to the joining portion 13 by drawing a gentle curve. In the board drying rail 10 according to the embodiment, the step 23 between the joining portion 13 and the non-joining portion 15 is 5 mm. Also, the length in the width direction of the original board of the non-joining portion 15 is 196 mm.

[0027] In the state of being disposed between the original boards 1, the board drying rail 10 has a joining portion 19 that joins over the entire width region in the width direction of the wood back 17 of the original board 1 when viewed from the cross-sectional direction of the original board 1. A wood back facing portion 18 is formed from the joining portion 19. In the embodiment shown in FIG. 4, the original board 1 has a drying posture in which the wood surface 11 faces downward and the wood back 17 faces upward. And the board drying rail 10 also has a posture in which the wood surface facing portion 16 faces upward and the wood back facing portion 18 faces downward in accordance with that posture. Of course, it is also possible to dry in a posture in which the vertical directions of the original board 1 and the board drying rail 10 are reversed. That is, the original board 1 may take a drying posture in which the wood surface 11 faces upward and the wood back 17 faces downward, and the wood surface facing portion 16 of the board drying rail 10 may face downward and the wood back facing portion 18 may face upward.

[0028] FIG. 5 is an overall perspective view of the plank 10 for drying a raw board according to an embodiment of the present invention. The plank 10 for drying a raw board according to the embodiment is used in combination with four raw boards 1. The number of raw boards 1 to be combined is determined in consideration of the dimensions in the width direction of the raw board 1, the size and weight of the raw board assembly described later, the size of the drying apparatus to be used, and the like.

[0029] As shown in FIG. 5, the plank 10 for drying a raw board according to the embodiment is made by cutting a wood having a rectangular cross section with a height H and a width W and a longitudinal length L. As an example, the height H of the cross section is 15 to 30 mm, the width W of the cross section is 30 to 45 mm, and the longitudinal length L is 1000 to 1100 mm.

[0030] The plank 10 for drying a raw board made of wood has a feature that it is difficult to damage the raw board 1 because it has the same hardness as the raw board 1 to be combined. Further, it also has features such as easy availability of materials, easy processing, and low cost. Further, the plank 10 for drying a raw board can also be made using metal. When metal is used, it has a feature of excellent durability. Furthermore, the plank 10 for drying a raw board can also be made using a synthetic resin such as plastic. Note that the plank 10 for drying a raw board may be made by combining two or more members. Further, those members may be made using different materials such as wood, metal, and synthetic resin.

[0031] FIG. 6 is a photograph of the raw board assembly 20 viewed from the cross-sectional direction of the raw board 1. As shown in FIG. 6, the raw board assembly 20 is configured by arranging a plurality of raw boards 1 with their plate surfaces facing up and down horizontally along the longitudinal direction, further stacking them in a plurality of stages while arranging the planks 10 for drying a raw board according to the embodiment at equal intervals in the longitudinal direction of the raw board 1, and placing a weight (not shown) on the upper part thereof. In the raw board assembly 20 according to the embodiment, four raw boards 1 are arranged horizontally. Further, the raw boards 1 are stacked in 20 stages.

[0032] Figure 7 is a photograph of the entire original plate assembly 20 with the concrete weight 21 placed on it. The weight of the weight is 1 to 1.5 t. Sleepers 22 are arranged under the weight 21. Also, sleepers 22 are arranged under the original plate assembly 20. By arranging the sleepers 22, a gap can be provided for the forklift claws to enter during forklift operation. Also, the original plate assembly 20 can be prevented from directly touching the ground. Note that the original plate drying slats 10 shown in Figure 7 are arranged at intervals of 0.7 to 1 m in the longitudinal direction of the original plate 1.

[0033] First, the above-described original plate assembly 20 enters the natural drying process and is naturally dried by natural wind, thereby reducing the moisture content of the original plate 1. Next, the original plate assembly 20 enters the artificial drying process and is placed in a dryer and dried at a drying temperature of 50 to 70°C. As a result, the original plate 1 is dried until the moisture content is 18% or less, and the drying of the original plate is completed.

[0034] The operation and effects of the original plate drying slats 10 according to the embodiment described above in terms of its configuration and process, and the original plate drying method using the original plate drying slats 10 will be described.

[0035] Figure 8 is a diagram showing the state in which the original plate 1 sawn from a log, which is the object of the original plate drying slats 10 of the present invention, is deformed (warped) by drying. As shown in Figure 8, the original plate 1 sawn along the grain has the property that the shrinkage amount on the wood surface side is larger than the shrinkage amount on the wood back side caused by drying, so it always deforms into a shape where the wood back is convex and the wood surface is concave.

[0036] Figure 9 is a diagram for explaining the force acting on the original plate 1 when the original plate 1 is dried using the original plate drying slats 10 according to the embodiment.

[0037] As shown in Figure 9, on the wood surface 11 side, a large force 30 acts on both end regions 12 in the width direction of the original plate 1. The force 30 is due to the weight of the weight 21 and the weight of other original plates 1 stacked above the illustrated original plate 1. At this time, no force acts on the middle region 14 in the width direction of the wood surface 11. Therefore, no slat marks are generated in the middle region 14 in the width direction of the wood surface 11.

[0038] On the other hand, as shown in FIG. 9, the load is dispersed on the back side of the board 17, and a force acts on the original board 1. That is, a considerably large force 31 acts on the part of the back side 17 corresponding to the both end regions 12 in the width direction of the front side of the board, which is smaller than the force 30 acting on the front side 11 of the board. Further, a distributed load 32 acts on the part of the back side 17 corresponding to the middle region 14 in the width direction of the front side of the board. The corresponding range of the front side 11 of the original board 1 is the non-joint part 15 of the cross bars 10 for drying the original board, and no force acts on this part from below. Therefore, the magnitude per unit length of the distributed load 32 becomes a very small value. As a result, no cross-bar marks are generated in the part of the back side 17 corresponding to the middle region 14 in the width direction of the front side of the board.

[0039] Also, as described with reference to FIG. 8, during the drying of the original board 1, the original board 1 tends to be deformed so as to be convex upward. However, the deformation is suppressed by the above-described distributed load 32 acting from the opposite direction. In this way, the middle region 14 in the width direction of the back side 17 of the original board 1 is in an excellent balance, and the generation of cross-bar marks is suppressed while the deformation is suppressed.

[0040] As described above, when the original board 1 is dried using the cross bars 10 for drying the original board according to the embodiment, no cross-bar marks are generated not only on the front side but also on the back side of the original board 1 corresponding to the non-joint part 15 of the cross bars 10 for drying the original board in the middle region 14 in the width direction.

[0041] FIG. 10 is a diagram for explaining a cross section when the original board 1 is formed into a floor board material 40 by planer processing. Both ends in the width direction of the original board 1 are subjected to rabbet processing. That is, one end in the width direction is processed into a male rabbet, and the other end in the width direction is processed into a female rabbet. Further, a small amount of finish planer processing is performed on the upper and lower surfaces of the plate surface of the original board 1. There is a possibility of cross-bar marks being generated in both end regions in the width direction of the original board 1, but even if they are generated, when the original board 1 is used, usually, both ends in the width direction of the original board 1 are processed into a male rabbet and a female rabbet, and the both end regions in the width direction are cut off, so no cross-bar marks remain.

[0042] Figure 11 (photo) shows a floor board 40 obtained by subjecting a raw board 1 dried using the raw board drying bar 10 according to the present embodiment to a planer process. As shown in Figure 11, no bar marks are observed on the floor board 40.

[0043] Figure 12 (photo) shows a floor 41 of a house using the floor board 40 shown in Figure 11. There are no bar marks on the floor 41, and it is extremely excellent in appearance.

[0044] As described above, by using the raw board drying bar 10 of the present invention, no bar marks remain when drying the raw board 1 sawn into planks from a round log. By using the dried raw board, a high-quality solid wood board can be produced. Also, according to the raw board drying method of the present invention, similarly, a raw board sawn into planks from a round log can be dried into a solid wood board without bar marks remaining.

[0045] According to the raw board drying bar of the present invention and the raw board drying method using the same, no new machine or new labor is required, and no new cost is incurred, and bar marks can be eliminated. That is, while continuing the conventional production method, a raw board sawn into planks from a round log can be dried to produce a high-quality solid wood board without bar marks remaining.

[0046] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Additions, omissions, substitutions, and other modifications of the configuration are possible without departing from the spirit of the present invention. The present invention is not limited by the above description but is defined by the appended claims.

Explanation of Reference Numerals

[0047] 1: Raw board 10: Raw board drying bar 11: Wood surface 12: Both end regions in the width direction of the wood surface 13: Joint portion 14: Middle region in the width direction of the wood surface 15: Non-joint portion 16: Wood surface facing part 17: Wood back 18: Wood back facing part 19: Joint part 20: Original plate assembly 21: Weight

Claims

1. When drying a raw board sawn from a log into planks, a crosspiece for drying the raw board, which is arranged above and below the raw board perpendicular to the longitudinal direction of the raw board, wherein the crosspiece for drying the raw board in a state of being arranged between the raw boards, when viewed from the cross-sectional direction of the raw board, has a wood surface facing portion having a joint portion that joins both end regions in the width direction of the wood surface of the raw board and a non-joint portion that does not join the intermediate region in the width direction of the wood surface of the raw board, and a wood back facing portion having a joint portion that joins over the entire width region in the width direction of the wood back of the raw board, and the crosspiece for drying the raw board is provided with the above.

2. The crosspiece for drying the raw board according to Claim 1, wherein the ratio of the length of the non-joint portion of the wood surface facing portion to the width dimension of the raw board is in the range of 70% to 90%.

3. The crosspiece for drying the raw board according to Claim 2, wherein the non-joint portion of the wood surface facing portion is parallel to the joint portion of the wood back facing portion.

4. The crosspiece for drying the raw board according to Claim 3, wherein the material of the crosspiece for drying the raw board is wood.

5. A plurality of the raw boards with their surfaces facing up and down are arranged horizontally side by side along the longitudinal direction, and further stacked in multiple layers while arranging the crosspiece for drying the raw board according to Claim 1 at equal intervals in the longitudinal direction of the raw board. After constructing a raw board assembly with a weight placed on its upper part, a natural drying step of naturally drying the raw board assembly, and an artificial drying step of putting the raw board assembly into a dryer for drying, and by going through the above, a raw board drying method for drying the moisture content of the raw board to a predetermined value or less.

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