JP7706205B1 - Original board drying bar and original board drying method using same - Google Patents

Abstract

[Problem] In the conventional method of drying raw boards using crosspieces, crosspiece marks remain on the raw boards after drying, which leads to a significant decrease in the marketability of the solid wood boards after raw board processing.
[Solution] When drying a raw board 1 sawn into flat grain from a log, raw board drying battens 10 are arranged above and below the raw board 1 perpendicular to the longitudinal direction of the raw board 1, and when arranged between the raw boards 1, the raw board drying battens 10, when viewed in the cross-sectional direction of the raw board 1, have a wood surface facing portion 16 having joint portions 13 that join with both widthwise end regions 12 of the wood surface 11 of the raw board 1 and a non-joining portion 15 that does not join with the widthwise middle region 14 of the wood surface 11 of the raw board 1, and a wood back facing portion 18 having a joint portion 19 that joins across the entire widthwise region of the wood back 17 of the raw board 1.
[Selected figure] Figure 4

Description

The present invention relates to a technique for drying boards that are arranged above and below a long board perpendicular to the longitudinal direction of the board when drying the board that has been sawn into planks from a log, and a method for drying boards that uses the board drying boards.

In recent years, there has been an increase in the use of solid wood boards, which are boards cut from a single tree and used as is without the use of adhesives or other chemicals.

Solid wood boards have the following excellent features: "They are less harmful to your health because they do not use adhesives or chemicals," "They have a high moisture retention effect and create a comfortable indoor environment," "You can enjoy the texture and feel of the wood itself," "Natural wood is less likely to cause sudden changes in humidity in a room and prevents dampness and dryness by absorbing and releasing moisture in the air," and "The more you use it, the more profound the feel and character it acquires, and it is easy to repair."

For this reason, solid wood boards are widely used for applications such as "floors and walls of homes,""furniture such as tables, chests of drawers, and television cabinets," and "structural materials such as pillars."
Known types of wood used for solid boards include cedar, cypress, oak, and walnut.

Incidentally, a drying process is essential for solid wood boards sawn from logs to dry them to a specified moisture content in order to prevent shrinkage after construction. In this drying process, as shown in Figure 1 (photo), multiple original boards 1 are lined up horizontally along the length with the board surfaces facing up and down, and the original boards 1 are stacked in multiple layers with crosspieces 2 placed at approximately equal intervals along the length of the original boards 1. The crosspieces 2 are essential for creating air passages between the upper and lower original boards 1 for drying. A weight (not shown) is placed on top of the stacked original boards 1 as shown in Figure 1, and the boards undergo a specified drying process to become solid wood boards.

However, a major problem arises at this point. As shown in Figure 2 (photo), after the drying process, dark or light colored crosspiece marks 3 remain on the parts of the original board 1 where the crosspieces 2 were in contact. Crosspiece marks 3 are thought to be caused by the concentration and chemical changes of extracted components that occur when moisture moves during the drying of the original board 1. Crosspiece marks 3 penetrate deep into the board, not just the surface of the board 1. Furthermore, crosspiece marks 3 are amplified by the clear coat applied when the board is used as a solid board.

Figure 3 (photo) shows a floor 5 of a house, where original boards 1 with crosspiece marks 3 are planed and clear coated to create finished floorboards 4. Crosspiece marks 3 are scattered in patches on the surface of the floorboards 4. In this way, the crosspiece marks 3 ruin the aesthetic look of the floor 5, which is made of solid wood and whose natural texture should be enjoyed. In other words, the crosspiece marks 3 greatly reduce the marketability of the solid wood.

A method of drying wood to prevent the formation of crosspiece marks has been proposed. Patent Document 1 proposes a method of drying wood by placing crosspieces between the upper and lower surfaces of a square bar, on which numerous parallel uneven stripes that cross the length direction are formed, and on which the surface width of each of the protruding stripes is 5 mm or less, preferably 3 mm or less. Patent Document 1 states that substantially no color patterns caused by the crosspieces are formed on the surface of wood dried using this method.

Special Publication No. 6-38024

The crosspieces in Patent Document 1 are formed with uneven strips, so the convex strips of the crosspieces come into contact with the original plate. This means that the contact pressure between the convex strips of the crosspieces and the original plate is higher than the contact pressure of normal crosspieces. This means that there is a risk that crosspiece marks will be generated in the parts of the original plate that come into contact with the convex strips.

The inventors of the present application therefore focused on the fact that when a raw board made by sawing raw wood into planks has the property of always deforming into a shape in which the center of the back of the wood is convex as it dries. In other words, they invented a raw board drying batten that does not leave batten marks by having a non-jointed portion that is not joined to the middle region in the width direction of the front of the raw board. Furthermore, they propose a raw board drying method that uses this raw board drying batten.

The raw board drying battens according to the first invention are raw board drying battens that are arranged above and below the raw board perpendicular to the longitudinal direction of the raw board when drying the raw board sawn into flat grain from a log, and are characterized in that when arranged between the raw boards, the raw board drying battens have a wood surface facing portion having a joint portion that joins both end widthwise regions of the wood surface of the raw board and a non-joining portion that does not join to the widthwise middle region of the wood surface of the raw board when viewed from the cross-sectional direction of the raw board, and a wood back facing portion having a joint portion that joins over the entire widthwise region of the wood back of the raw board.

In the raw board drying battens of the first invention, the widthwise middle region of the wooden surface of the raw board is not joined to the raw board drying battens, so no batten marks are left in the widthwise middle region of the wooden surface of the raw board. Also, the wooden back of the raw board is joined to the facing part of the wooden back of the raw board drying battens, but the contact pressure is extremely low, so no batten marks are left in the widthwise middle region of the wooden back of the raw board. During drying, the raw board tries to deform (warp) into a shape with the center of the wooden back being convex, but this deformation is restricted by the facing part of the wooden back of the raw board drying battens, and a straight flat surface is maintained.

The second invention relates to a bar for drying raw boards, characterized in that the ratio of the length of the non-jointed portion of the facing wood surface to the width dimension of the raw board is in the range of 70% to 90%.

The second invention of the raw board drying battens does not leave batten marks on either the front or back of the board within a range of 70% to 90% of the width of the raw board, so it does not impair the appearance in any practical sense.

The third invention relates to a bar for drying raw boards, characterized in that the non-jointed portion of the wood surface facing portion is parallel to the jointed portion of the wood back facing portion.

The third invention relates to a bar for drying raw boards, and the wooden surface facing portion can be easily formed by simply carving the non-jointed portion of the wooden surface facing portion into a shape that is slightly recessed from the joint portion of the wooden surface so that it is parallel to the joint portion of the wooden back facing portion.

The raw board drying bar of the fourth invention is characterized in that the raw board drying bar is made of wood.

The raw board drying battens of the fourth invention are made of wood, so the non-jointed parts of the opposing wooden surfaces can be easily formed and processed.

The method for drying raw plates according to the fifth invention is characterized in that a number of the raw plates with their surfaces facing up and down are arranged horizontally along the longitudinal direction, and then the raw plate drying bars according to the first invention are arranged at equal intervals along the longitudinal direction of the raw plates, stacking them in multiple tiers, and forming an assembly of raw plates with a weight placed on top of it.The method is then characterized in that the moisture content of the raw plates is dried to a predetermined value or less through a natural drying process in which the assembly of raw plates is dried naturally, and an artificial drying process in which the assembly of raw plates is placed in a dryer and dried.

The fifth invention relates to a method for drying raw boards, and it is possible to dry the raw boards to a moisture content below a predetermined value without leaving any crosspiece marks.

By using the board drying battens of this invention, boards that have been sawn into planks from logs can be dried to produce solid boards without any batten marks.

Furthermore, according to the raw board drying method of the present invention, raw boards that have been sawn into planks from logs can be dried to produce solid boards that do not leave any crosspiece marks.

The photograph shows multiple original boards lined up horizontally along their length with the board surfaces facing up and down, and then stacked in multiple layers with traditional crosspieces placed at equal intervals along the length of the original boards. This is a photograph showing the original board after the drying process, with crosspiece marks remaining in the areas where the crosspieces had been in contact. This is a photograph showing the floor of a house in which solid wood flooring was used, manufactured by planing original boards with batten marks. This is an enlarged view of the main parts of an embodiment of a raw board drying batten that is arranged above and below the raw board perpendicular to the longitudinal direction of the raw board when drying the raw board that has been sawn into flat grain from a log, as viewed from the cross-sectional direction of the raw board. 1 is an overall perspective view of a raw sheet drying rail according to the present invention; 1 is a photograph of an aggregate of original plates viewed from the cross-sectional direction of the original plates. This is a photograph of the entire assembly of original plates with weights placed on them. FIG. 2 is a diagram showing the state in which a raw board, which is the subject of the raw board drying batten of the present invention and which has been sawn into a tang, has been deformed (warped) due to drying. 10A to 10C are diagrams illustrating forces acting on an original plate when the original plate is dried using an original plate drying bar according to an embodiment. FIG. 2 is a diagram illustrating a cross section of an original board when it is turned into a floor board material by planar processing. This is a photograph of flooring material in which the original board has been planarized after drying. 12 is a photograph of a floor of a house using the flooring material shown in FIG. 11.

Figure 4 is an enlarged view of the essential parts of the raw board drying battens 10 according to the embodiment, which are arranged above and below the raw board 1 perpendicular to the longitudinal direction of the raw board 1 when drying the raw board 1 that has been sawn into planks from a log, as viewed from the cross-sectional direction of the raw board 1. Note that the dimensions of the raw board 1 as an example according to the embodiment are a thickness of 40 mm, a width of 250 mm, and a longitudinal length of 4000 mm.

As shown in FIG. 4, when arranged between the raw boards 1, the raw board drying battens 10 have joint parts 13 that join both widthwise end regions 12 of the wooden surface 11 of the raw board 1 when viewed from the cross-sectional direction of the raw board 1. The raw board drying battens 10 also have non-joined parts 15 that do not join the widthwise middle region 14 of the wooden surface 11 of the raw board 1. In the raw board drying battens 10 according to the embodiment, the wooden surface facing part 16 is composed of the joint parts 13 and the non-joined parts 15. The left and right ends of the non-joined parts 15 are connected to the joint parts 13 by drawing a gentle curve. In the raw board drying battens 10 according to the embodiment, the step 23 between the joint parts 13 and the non-joined parts 15 is 5 mm. In addition, the length of the non-joined parts 15 in the width direction of the raw board is 196 mm.

When arranged between the raw boards 1, the raw board drying rails 10 have joints 19 that join to the entire widthwise area of the wood backs 17 of the raw boards 1 when viewed from the cross-sectional direction of the raw boards 1. The joints 19 form wood back facing portions 18.
In the embodiment shown in Fig. 4, the raw board 1 is in a drying position with the surface 11 facing downward and the back surface 17 facing upward. The raw board drying rail 10 is also in a position where the surface facing portion 16 faces upward and the back surface facing portion 18 faces downward in accordance with the drying position.
Of course, the raw board 1 and the raw board drying bar 10 may be turned upside down for drying. That is, the raw board 1 may be dried with the wooden surface 11 facing upward and the wooden back surface 17 facing downward, while the raw board drying bar 10 may be dried with the wooden surface facing portion 16 facing downward and the wooden back surface facing portion 18 facing upward.

Figure 5 is an overall perspective view of an original plate drying rail 10 according to an embodiment of the present invention. The original plate drying rail 10 according to the embodiment is used in combination with four original plates 1. The number of original plates 1 to be combined is determined taking into consideration the width dimension of the original plate 1, the size and weight of the original plate assembly described below, the size of the drying device to be used, etc.

As shown in Figure 5, the original board drying bar 10 according to the embodiment has a rectangular cross section with height H and width W, and is manufactured by cutting wood with a longitudinal length L. As an example, the cross-sectional height H is 15 to 30 mm, the cross-sectional width W is 30 to 45 mm, and the longitudinal length L is 1000 to 1100 mm.

The raw board drying bar 10 made of wood has the same hardness as the raw board 1 to be combined, and is therefore characterized by being less likely to damage the raw board 1. In addition, the raw board drying bar 10 has the characteristics that the material is easy to obtain, easy to process, and inexpensive. The raw board drying bar 10 can also be made using metal. When metal is used, it has the characteristic of being highly durable. Furthermore, the raw board drying bar 10 can also be made using synthetic resin such as plastic.
The original board drying bar 10 may be manufactured by combining two or more members. Furthermore, these members may be manufactured by using different materials such as wood, metal, synthetic resin, etc.

Figure 6 is a photograph of the original plate assembly 20 viewed from the cross-sectional direction of the original plate 1. As shown in Figure 6, the original plate assembly 20 is configured by arranging multiple original plates 1 with their plate surfaces facing up and down horizontally along the longitudinal direction, stacking them in multiple layers with original plate drying bars 10 according to the embodiment arranged at equal intervals along the longitudinal direction of the original plates 1, and placing a weight (not shown) on top of them. The original plate assembly 20 according to the embodiment has four original plates 1 arranged horizontally. Furthermore, the original plates 1 are stacked in 20 layers.

Figure 7 is a photograph of the entire original board assembly 20 with a concrete weight 21 placed on it. The weight is 1 to 1.5 t. A crosstie 22 is placed under the weight 21. A crosstie 22 is also placed under the original board assembly 20. By placing the crosstie 22, a gap can be provided for the claws of a forklift to fit in during operation. It also prevents the original board assembly 20 from coming into direct contact with the ground. The original board drying battens 10 shown in Figure 7 are placed at intervals of 0.7 to 1 m in the longitudinal direction of the original board 1.

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

The above describes the configuration and process of the embodiment of the original plate drying bar 10, and the action and effect of the original plate drying method using the original plate drying bar 10.

Figure 8 shows the state of the raw board 1, which is sawn into a plank from a log that is the subject of the raw board drying batten 10 of the present invention, deformed (warped) due to drying. As shown in Figure 8, the raw board 1 sawn into a plank has a tendency to deform into a shape in which the back side is convex and the front side is concave because the amount of shrinkage caused by drying on the front side is greater than the amount of shrinkage on the back side.

Figure 9 is a diagram illustrating the forces acting on the original plate 1 when the original plate 1 is dried using the original plate drying bar 10 according to the embodiment.

As shown in FIG. 9, on the wooden surface 11 side, a large force 30 is acting on both end widthwise regions 12 of the original board 1. The force 30 is due to the weight of the weight 21 and the weight of other original boards 1 stacked above the illustrated original board 1. At this time, no force is acting on the widthwise middle region 14 of the wooden surface 11. Therefore, no crosspiece marks are generated in the widthwise middle region 14 of the wooden surface 11.

On the other hand, as shown in Figure 9, the load is distributed on the back side 17 of the board 1, and the force acts on the board. That is, a force 31, which is smaller than the force 30 acting on the front side 11 but is still quite large, acts on the part of the back side 17 that corresponds to the widthwise end regions 12 of the front side. Furthermore, a distributed load 32 acts on the part of the back side 17 that corresponds to the widthwise middle region 14 of the front side. The corresponding range of the front side 11 of the board 1 is the non-jointed portion 15 of the board drying battens 10, and no force acts on this part from below. Therefore, the magnitude of the distributed load 32 per unit length is very small. As a result, no batten marks are generated on the part of the back side 17 that corresponds to the widthwise middle region 14 of the front side.

Also, as explained in Figure 8, while the original board 1 is drying, the original board 1 tends to deform so as to become convex upward. However, this deformation is suppressed by the distributed load 32 acting from the opposite direction. In this way, the widthwise middle region 14 of the wood back 17 of the original board 1 is exquisitely balanced to suppress deformation while also suppressing the occurrence of crosspiece marks.

As described above, when the raw board 1 is dried using the raw board drying bar 10 according to the embodiment, no bar marks are generated on the front or back of the raw board in the widthwise middle region 14 of the raw board 1, which corresponds to the non-jointed portion 15 of the raw board drying bar 10.

Figure 10 is a diagram illustrating the cross section of the original board 1 when it is turned into flooring material 40 by planing. Both ends of the width direction of the original board 1 are subjected to a groove processing. That is, one end of the width direction is processed into a male groove, and the other end of the width direction is processed into a female groove. In addition, a small amount of finish planing is performed on the top and bottom surfaces of the board surface of the original board 1. There is a possibility of crosspiece marks occurring in the both end regions of the width direction of the original board 1, but even if they do occur, when the original board 1 is used, both ends of the width direction of the original board 1 are usually processed into male and female grooves and the both end regions of the width direction are scraped off, so no crosspiece marks remain.

Figure 11 (photo) shows a flooring material 40 in which planar processing has been applied to a raw board 1 that has been dried using the raw board drying battens 10 according to this embodiment. As shown in Figure 11, no batten marks can be seen on the flooring material 40.

Figure 12 (photo) shows the floor 41 of a house that uses the floorboard material 40 shown in Figure 11. There are absolutely no batten marks on the floor 41, making it very aesthetically pleasing.

As described above, by using the raw board drying battens 10 of the present invention, no batten marks remain when the raw board 1 sawn into planks from a log is dried. By using the raw board after drying, high-quality solid boards can be produced.
Furthermore, according to the raw board drying method of the present invention, raw boards that have been sawn into cross grains from logs can be dried to produce solid boards that are free of crosspiece marks.

The raw board drying battens of the present invention, and the raw board drying method using the same, can eliminate batten marks without requiring new machinery, new labor, or new costs. In other words, while continuing with conventional production methods, it is possible to dry raw boards that have been sawn into planks from logs, and produce high-quality solid boards that do not leave batten marks.

The above describes preferred embodiments of the present invention, but the present invention is not limited to these embodiments. Addition, omission, substitution, 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.

1: Original board 10: Original board drying rail 11: Wood surface 12: Width direction both end regions of the wood surface 13: Joint portion 14: Width direction middle region of the wood surface 15: Non-joined portion 16: Wood surface facing portion 17: Wood back 18: Wood back facing portion 19: Joint portion 20: Original board assembly 21: Weight

Claims (5)

A raw board drying battens arranged above and below the raw board perpendicular to the longitudinal direction of the raw board when drying the raw board that has been sawn into a timber grain from a raw log,
The raw plate drying bar is
a wood surface facing portion having a joining portion that joins both end regions of the wood surface of the original plate in the width direction and a non-joining portion that does not join to a middle region of the wood surface of the original plate in the width direction when viewed from a cross-sectional direction of the original plate when the wood surface is disposed between the original plates;
A wood back facing portion having a joint portion that joins the entire width direction of the wood back of the original board;
A bar for drying raw boards. The bar for drying raw boards according to claim 1, in which the ratio of the length of the non-jointed portion of the facing wood surface to the width dimension of the raw board is in the range of 70% to 90%. The bar for drying raw boards according to claim 2, wherein the non-jointed portion of the wood surface facing portion is parallel to the jointed portion of the wood back facing portion. The board drying bar according to claim 3, wherein the material of the board drying bar is wood. A plurality of the raw plates are arranged horizontally along the longitudinal direction with the plate surfaces facing up and down, and the raw plate drying bars according to claim 1 are arranged at equal intervals in the longitudinal direction of the raw plates and stacked in a plurality of tiers, and a weight is placed on the upper part of the raw plate assembly to form the raw plate assembly.
a natural drying step of naturally drying the original plate assembly;
an artificial drying step of drying the raw plate assembly in a dryer;
The method for drying an original sheet includes drying the original sheet to a moisture content of a predetermined value or less through the above steps.

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