JP5685096B2 - Method for producing dry wood - Google Patents

Description

The present invention relates to a method for producing dry wood.

As domestic structural materials such as pillar materials, domestically-produced cedar and hinoki core-supported square materials such as cypress have been used. Increased. However, such a cored square member is liable to be cracked during drying, and similarly to the back split material, the dimensional stability after construction and construction is poor, which causes a problem. For this reason, the use of laminated wood having excellent dimensional stability is also increasing.
In recent years, a high-temperature drying method has been developed and spread to prevent cracking of the material surface that occurs during drying of cedar and cypress cored squares. In this high temperature drying method, it is said that the surface cracking is reduced by forming a drying set on the surface layer by drying at a dry bulb temperature of 120 ° C. in the initial stage of drying. According to the high temperature drying method, cracks on the surface of the material are relatively reduced, but it is not sufficient.

Further, the high temperature drying method has a problem that internal cracks are likely to occur. Internal cracks in the high-temperature drying method are considered to occur when the material surface layer is set to be dried in a tensile state, and thus the interior of the material cannot be freely contracted and the tensile stress increases.
In addition, cracking of the material surface is considered to occur in the initial stage of high-temperature drying, when the duration of the dry-bulb temperature of 120 ° C is not sufficient, the so-called drying set formation layer is shallow and tensile stress is still present on the surface layer. ing.
In order to prevent cracking of the material surface, if the duration of the dry bulb temperature of 120 ° C. is excessively increased, the layer of the drying set is deepened, but the drying speed is fast, so that the portion inside the surface of the drying set layer is 120. It is said that due to the dry bulb temperature of 0 ° C., a part of the inner layer starts to shrink rapidly, and the inner layer part is strongly restrained by the surface drying set, so that the tensile stress increases and an internal crack occurs.

  As a drying schedule control method for reducing such material surface cracks and internal cracks, a method of proceeding drying while measuring the temperature and moisture content in the wood (see Patent Document 1) is known. In addition, the applicant of the present invention is a method of proceeding with drying while controlling drying conditions based on data obtained from strain detection means fixed inside the wood (see Patent Document 2), and two adjacent sides of a square bar. A method of advancing drying while fixing a pair of displacement gauge fixing jigs and measuring a displacement generated during drying with a displacement gauge fixed between the pair of displacement gauge fixing jigs (see Patent Document 3) Etc. were proposed.

  Further, as an artificial drying method for physically reducing material surface cracking and / or internal cracking, a technique of drying while constraining the outer periphery of wood with moisture permeable shrinkage restraining means (see Patent Document 4), or a wood mouthpiece A technique (see Patent Documents 5 and 6) for making a hole in a portion is known.

JP 2001-287206 A JP 2004-190957 A JP 2007-120902 A Japanese Patent Laid-Open No. 02-050072 Japanese Patent Laid-Open No. 02-155605 JP 2007-196507 A

  According to the methods of Patent Documents 1 to 3, it is possible to effectively prevent internal cracks and material surface cracks for wood with strain detection means, temperature and moisture content sensors, displacement gauges, and the like. When wood is placed in a dryer and dried at the same time, the moisture content of the wood often varies, making it difficult to perform appropriate drying control for each of the multiple woods having different moisture contents. It was difficult to manage the whole of a plurality of wood (drying material lot) to be dried.

  Moreover, although the method of patent documents 4-6 is recognized to some extent in the crack prevention effect, the operation | work which mounts a shrinkage | contraction restraining means so that the outer periphery of to-be-dried wood may be surrounded is complicated, or processing such as making a hole. It is labor-intensive and costly, such as the need to introduce additional dedicated machines.

  Therefore, the objective of this invention is providing the manufacturing method of the dry wood which can dry a wood efficiently, suppressing an internal crack.

  The present invention cuts the vicinity of the mouth end surface of wood to produce a cut surface that is substantially parallel to the end face and a protruding portion that protrudes from the position of the cut surface toward the end face side, and then artificially dry. The above object is achieved by providing a method for producing dry wood.

  According to the dry wood manufacturing method of the present invention, wood can be efficiently dried while suppressing internal cracks.

It is a schematic diagram which shows an example of the drying apparatus of the wood which can be used for implementation of this invention. It is a perspective view which shows the one end part vicinity of the to-be-dried wood in a 1st embodiment. This is wood before processing to prevent internal cracks on or near the end of the wood. It is a perspective view which shows the one end part vicinity of the to-be-dried wood in a 2nd embodiment. It is a perspective view which shows the one end part vicinity of the to-be-dried wood in a 1st reference aspect. It is a perspective view which shows the one end part vicinity of the to-be-dried wood in a 2nd reference aspect. It is a perspective view which shows the one end part vicinity of the to-be-dried wood in a 3rd embodiment. It is the figure which looked at the end face of one end of the to-be-dried wood in the modification of the first embodiment from the axial direction. It is the figure which looked at the end face of one end of the to-be-dried wood in the modification of the 2nd embodiment from the axial direction. It is the figure which looked at the end face of one end of the to-be-dried wood in the modification (reference aspect) of the 2nd reference aspect from the axial direction. It is a graph which shows an example of a drying schedule.

Hereinafter, the present invention will be described based on preferred embodiments thereof.
It is preferable to use the drying apparatus provided with the drying chamber which can control temperature and humidity for implementation of the manufacturing method of the dry wood of this invention.
FIG. 1 shows an example of such a drying apparatus, which includes a drying chamber 1 capable of controlling the temperature and humidity, and a wood 10 accommodated in the drying chamber 1 having a temperature and humidity in the drying chamber 1. Can be dried under control.

  More specifically, the wood drying apparatus of FIG. 1 includes a drying chamber 1 that houses the wood 10 to be dried, a vaporization mechanism 2 that injects steam into the drying chamber 1, and the air in the drying chamber 1. A heating mechanism 3 that heats the air, an air supply mechanism 4 that introduces outside air into the drying chamber 1, and an exhaust mechanism 5 that exhausts the air in the drying chamber 1 to the outside.

  The steaming mechanism 2 is configured to introduce steam generated in a steam generating device (boiler or the like) 21 into the drying chamber 1 through a steam introduction pipe 22 connected to the drying chamber 1. Steaming into the drying chamber can be controlled by opening and closing a control valve 23 such as an electromagnetic valve or an electric valve provided in the introduction pipe 22. The heating mechanism 3 is configured to heat the air in the drying chamber 1 by circulating a heating medium (steam) in the heating pipe 31 piped in the drying chamber 1, and the circulation and flow rate of the heating medium. The heating can be controlled by controlling the temperature and the like. The air supply mechanism 4 and the exhaust mechanism 5 are mainly composed of ducts 41 and 51 communicating with the inside and outside of the drying chamber 1 and a fan (not shown) that generates an air flow in the duct, respectively. The intake and exhaust of the drying chamber 1 can be controlled by controlling the rotation of the fan and the opening and closing of the dampers 42 and 52 provided in the duct.

Then, by appropriately controlling the vaporization by the vaporization mechanism 2, the heating by the heating mechanism 3, the air supply by the air supply mechanism 4, and the exhaust by the exhaust mechanism 5, the temperature and humidity in the drying chamber 1 can be set as desired. The temperature and humidity can be controlled.
The drying apparatus may include a temperature measuring means 6 that can measure the temperature inside the wood during drying and a moisture content measuring means 7 that can measure the moisture content inside the wood during drying. Further, the temperature measuring means 6 and the moisture content measuring means 7 may each be capable of measuring the temperature or moisture content inside the wood at two or more parts having different depths from the wood surface. As the temperature measuring means and the moisture content measuring means, for example, those described in Patent Document 1 can be used.
In addition, the drying device fixes a pair of displacement gauge fixing jigs to two adjacent side surfaces of the wood (corner) 10 and a displacement meter fixed between the pair of displacement gauge fixing jigs is drying. You may provide the displacement measurement means which measures the displacement which arises in a square member. As an example of such a displacement measuring means, for example, the one described in Patent Document 3 can be used.

  The drying apparatus shown in FIG. 1 includes a control calculation unit 8 electrically connected to a temperature and hygrometer (not shown) installed in the drying chamber 1. The control calculation unit 8 is mainly composed of a personal computer. The calculation unit 8 is also electrically connected with a temperature measurement unit 6, a moisture content measurement unit 7, a displacement measurement unit (not shown), and the like. The temperature, the moisture content, and the amount of displacement generated inside the wood are calculated and output on the display means 9 and / or the printer 11 ′ continuously or at predetermined intervals. The control calculation unit 8 is adapted to change the temperature and humidity in the drying chamber 1 over time in accordance with a predetermined control schedule input from the input means 12 ′, and appropriately adjusts the schedule during drying. It is also possible to make changes.

In the method for producing dry wood according to the present invention, after a predetermined processing for suppressing internal cracks is performed on or near the mouth end of the wood to be dried (wood to be dried), the wood is artificially dried. I do.
Artificial drying is drying performed under the control of temperature or temperature and humidity in a space where at least temperature, preferably both temperature and humidity, can be controlled, as in the drying chamber 1 of the drying apparatus shown in FIG. Or vacuum drying. Artificial drying preferably has a high temperature drying step (dry bulb) at a temperature above 100 ° C. and 140 ° C. or less, and more preferably has a high temperature drying step at a (dry bulb) temperature of 110 to 130 ° C. Artificial drying may be intermediate temperature drying in which wood is dried by heating to a temperature of 100 ° C. or lower (for example, 50 to 100 ° C.), reduced pressure drying with heating or reduced pressure drying without heating, or the like.

  The predetermined processing for suppressing the internal cracking of the wood may be performed only on the end face of one end in the longitudinal direction of the wood, but is preferably performed on both end faces in the longitudinal direction.

In the first embodiment of the present invention, the vicinity of the both mouth end surfaces 11 (only one shown) at both ends in the longitudinal direction of the wood 10 ', which is a cored square member as shown in FIG. As shown in FIG. 2, in the vicinity of each of the both end surfaces 11, a cut surface 12 substantially parallel to the end surface 11, and the position P <b> 1 of the cut surface 12 toward the end surface 11 (arrow X <b> 1 side in FIG. 2). The to-be-dried wood 10A (10) in which the protruding portion 13 is generated is obtained.
More specifically, using an electric circular saw, slit-like cuts 15 and 16 having a predetermined depth are respectively formed on the two opposite side surfaces 14 and 14 of the wood 10 'which is a core-supported square member. Dry wood 10A is obtained.

  The slit-shaped cuts 15 and 16 in the wood to be dried 10 </ b> A are directed from the side surfaces 14 and 14 toward the central axis C of the wood 10 ′, and are formed substantially parallel to the end face 11. The central axis C is a straight line that passes through the center of the end face 11 of the wood 10 ', 10A and is parallel to the longitudinal direction (X direction) of the wood 10', 10A. Further, in the slit-like cuts 15 and 16 in the illustrated example, the depth L2 from the surface of the side surface 14 is constant in the Z direction in the figure, and the other side of the slit 14 is opened to the surface of the side surface 14 with a narrow width. It extends between the two opposite side surfaces 17, 17.

  As in the present embodiment, when slit-like cuts 15 and 16 are formed in the wood 10 ′ to form a cut surface 12 substantially parallel to the end face 11, both sides of the cut 15 in the X direction and the X of the cut 16 are formed. Although the cut surface will be produced on both sides in the direction, the cut surface 12 in the case where the protruding portion 13 protrudes from the position P1 of the cut surface 12 to the side of the head end 11 is the cut surface on the longitudinal center side of the wood Means. Therefore, the position of P1 in FIG. 2 is the position of the cut surface 12 in the longitudinal direction (X direction) of the wood.

  The protrusion 13 of the to-be-dried wood 10 </ b> A according to the present embodiment includes a protrusion central portion 13 </ b> A that overlaps the region 18 between the cut surfaces 12 and 12 and a pair of cut surfaces as viewed from the direction perpendicular to the end face 11. 12 and 12 and side extension parts 13B and 13B which are parts which overlap with each. The protruding portion central portion 13A is continuous with the longitudinal direction central portion side of the wood 10A through the region 18, and the pair of laterally extending portions 13B and 13B are laterally extending from the protruding portion central portion 13A in the Y direction. Overhangs. The central portion in the longitudinal direction of the wood 10A is located in the arrow X2 direction from the position P1 of the cut surface in FIG. Further, the Y direction and the Z direction are one direction and its orthogonal direction in a cross section orthogonal to the X direction.

As a means for forming the slit-shaped cuts 15 and 16, a circular saw, particularly a circular saw that is a power saw operated by an electric motor or an engine, is preferably used. In addition, the circular saw may be hand-held, but it is a stationary type, in particular, a circular blade built in a flat table that rotates at high speed, and the wood that has been moved on the table is cut into a straight line. Is preferably used.
Although FIG. 2 shows only one end face 11 side of the dry wood 10A (wood 10 ′), the same processing is performed on the other end face side.

Usually, when natural drying is performed, the drying conditions may be stricter than artificial drying, and damage tends to occur more than expected. For this reason, in the material, dry cracks are first generated on the surface of the material and the end of the end of the wood, and it is often extended to develop surface cracks and cracks of the material.
On the other hand, in the case of artificial drying, since the temperature, temperature and humidity can be set to arbitrary conditions, the occurrence of material surface cracks and internal cracks is reduced compared to natural drying. Therefore, usually, drying is started in a state of a solid material.
However, even if it is artificial drying, when high-temperature drying is used, the material often has many surface cracks and internal cracks. As a result of observing the cracking condition of the dried material, when cracking occurs, most of the internal cracks start cracking from the end of the wood, the crack extends in the longitudinal direction of the material, disappears in the middle of the material, It extended to the center of the longitudinal direction of the material.

  Further, it is known that the wood has the highest moisture conductivity in the longitudinal direction (axial direction) of the wood. In the case of artificial drying, since the drying temperature is higher than that of natural drying, the material is dried first from both ends of the material, and gradually dried toward the center. Actually, when examining the moisture content distribution in the longitudinal direction (axial direction) of the artificial desiccant, the moisture content is low at the ends of both ends, and the moisture content increases toward the center of the material.

  The present inventor considered that if a crack generated on or near the mouth end can be prevented, a crack proceeding from the crack to the center in the longitudinal direction can be effectively suppressed. Further, it has been found that by performing a predetermined cutting process in the vicinity of the end face, it is possible to effectively suppress the occurrence of internal cracks that proceed from the end face or the vicinity thereof.

In the first embodiment of the present invention, the above-described processing shown in FIG. 2 is performed as a cutting processing for suppressing internal cracks in the wood.
When drying the to-be-dried wood 10A, moisture evaporates from the mouth end surface 11 located at the tip of the protruding portion 13 and the above-described cut surfaces 12 and 12, and from each of them, the longitudinal direction of the wood (axial direction) The drying proceeds toward). In the case where the vicinity of the mouth end of the wood to be dried is not cut as in the prior art, the evaporation of moisture in the wood mainly occurs only from the end face of the wood, so that the drying is also from the end face toward the center of the longitudinal direction of the wood. In the same position in the longitudinal direction of the wood, the entire cross-section is in the same dry state. Therefore, a tensile force is generated in the circumferential direction of the annual ring to be contracted due to a decrease in the moisture content, and a portion that cannot withstand the tensile force is torn and an internal crack is generated. The internal crack is likely to have a shape extending in a direction perpendicular to the annual ring.

On the other hand, in the first embodiment, since the pair of cut surfaces 12 and 12 are formed at positions separated from the end surface 11, for example, at the position P1 of the cut surfaces 12 and 12, when artificial drying is performed. In contrast, the moisture content of the cut surface 12 starts to decrease immediately, whereas in the region 18 between the cut surfaces 12, it is difficult for the moisture to evaporate due to the presence of the protrusion central portion 13 </ b> A. Advances behind the cut surfaces 12 and 12. In addition, also at the position P2 in FIG. 2, it is considered that the drying of the portion that overlaps the protruding portion central portion 13A proceeds later than the portion that overlaps the cut surfaces 12 and 12.
According to the method of the present embodiment, in this way, by generating a portion having a high moisture content and a portion having a low moisture content in the same cross section, the annual ring direction generated when the same cross section in the longitudinal direction is dried at the same speed. Can be prevented or alleviated, and the occurrence of internal cracks can be suppressed. Moreover, by preventing the crack which generate | occur | produces in the vicinity of the end face, it is suppressed similarly that the crack progresses to the longitudinal direction center part side of a timber. Thereby, dry wood without internal cracks and dry wood with few internal cracks are obtained.

  From the viewpoint of preventing internal cracks, the distance L1 in the X direction from the end surface 11 of the wood 10A to each of the cut surfaces 12, 12 (see FIG. 2, the same as the protruding length of the protruding portion 13) is 5 to 300 mm, particularly 10 It is preferably ~ 100 mm. The distance L1 is preferably 5 to 300%, particularly 10 to 100% of the distance L3 between the side surfaces 14 and 14.

Further, the slit-shaped cuts 15 and 16 have a depth L2 (see FIG. 2) from the surface of the side surfaces 14 and 14 of 5 to 45%, particularly 20 to 40% of the distance L3 between the side surfaces 14 and 14, respectively. % Is preferred.
Moreover, the total area of the cut surfaces 12 and 12 is 10 to 90% of the total area of the cross section (cross section orthogonal to the X direction) of the wood to be dried 10A in the portion other than the portion having the cuts 15 and 16, particularly 40 to 80. % Is preferred.

  Moreover, it is preferable that the width W (refer FIG. 2) of the slit-shaped notches 15 and 16 is 1-10 mm, respectively, especially 2-6 mm.

Next, other embodiments and reference embodiments of the present invention will be described. Other embodiments and reference embodiments are the same as those in the first embodiment except that the processing applied to the surface of the mouth end or the vicinity thereof is different, and the points described above with respect to the first embodiment are the same unless otherwise described. Applicable as appropriate.

In the second embodiment, the vicinity of both the end surfaces 11 (only one is shown) at both ends in the longitudinal direction of the wood 10 ', which is a cored square member as shown in FIG. 3, is cut into a block shape and shown in FIG. The to-be-dried wood 10B (10) is obtained.
More specifically, after using the electric circular saw to cut the two opposite side surfaces 14 and 14 of the wood 10 ′, which is a cored square, to a predetermined depth, respectively, using the electric circular saw in the same manner, 11 are cut to a predetermined depth on both sides of the center axis C of the wood 10 ′, so that portions located on both sides of the center axis C of the wood 10 ′ are removed in the vicinity of the end face of the wood 10 ′. The part to be removed has a cubic shape. Further, the removal of the portions located on both sides of the central axis C is performed by cutting both sides of the central axis C of the butt face 11 perpendicularly to the butt face 11 to a predetermined depth, and then setting each of the two side surfaces 14 and 14 to a predetermined level. You may cut to depth. Further, instead of the electric circular saw, another cutting means may be used.

  In the obtained dry wood 10B, there are a cut surface 12 substantially parallel to the cut end surface 11 and the vicinity thereof on the both cut end surfaces 11 and the side of the cut end 12 from the position P1 of the cut end surface 12 (in FIG. 4, arrow X1 Projecting portion 13 projecting to the side). However, the protrusion part 13 consists only of a part corresponding to the protrusion part center part 13A in the first embodiment, and does not have a part corresponding to the side extension parts 13B and 13B.

Also in the second embodiment, since the pair of cut surfaces 12 and 12 are generated at positions separated from the distal end surface 13a (the end surface 11) of the protrusion 13, for example, at the position P1 of the cut surfaces 12 and 12, When artificially drying, the moisture content of the cut surface 12 starts to decrease immediately, whereas in the region 18 between the cut surfaces 12 and 12, it is difficult for the moisture to evaporate due to the presence of the protruding portion 13. The decrease in the moisture content proceeds later than the cut surfaces 12 and 12. In addition, at the position P2 in FIG. 4, it is considered that the drying of the portion overlapping the protruding portion 13 proceeds later than the portion overlapping the cut surfaces 12 and 12.
According to the second embodiment, in this way, by generating a portion having a high moisture content and a portion having a low moisture content in the same cross section, the annual ring direction generated when the same cross section in the longitudinal direction is dried at the same speed. The tension can be alleviated and the occurrence of internal cracks can be suppressed. Moreover, by preventing the crack which generate | occur | produces in the vicinity of a mouth end surface, the crack which a crack progresses and advances to the longitudinal direction center part side of a timber is suppressed similarly. Thereby, dry wood without internal cracks and dry wood with few internal cracks are obtained.

  From the viewpoint of preventing internal cracks, the distance L1 (see FIG. 4, same as the protruding length of the protruding portion 13) from the front end surface 13a (the end surface 11) of the protruding portion 13 to each of the cut surfaces 12, 12 is 5 to 300 mm. In particular, the thickness is preferably 10 to 100 mm. The distance L1 is preferably 5 to 300%, particularly 10 to 100% of the distance L3 between the side surfaces 14 and 14.

  Moreover, it is preferable that the dimension L2 (refer FIG. 4) of the Y direction of the cut surfaces 12 and 12 is 5 to 45% of the distance L3 between the side surfaces 14 and 14, respectively, especially 20 to 40%. Further, the total area of the cut surfaces 12 and 12 is 10 to 90%, particularly 40 to 80%, of the total area of the cross section (cross section orthogonal to the longitudinal direction) of the wood to be dried 10B in the portion other than the protruding portion 13. Is preferred.

In the first reference embodiment, slit-like cuts perpendicular to the respective mouth surfaces 11 are respectively formed on both end surfaces 11 (only one is shown) at both ends in the longitudinal direction of the wood 10 'which is a cored square member as shown in FIG. 19 is put, and the to-be-dried wood 10C (10) shown in FIG. 5 is obtained. More specifically, four linear cuts 19 </ b> A to 19 </ b> D connecting the center portions 14 a and 17 a of two adjacent sides of the end surface 11 are perpendicular to the end surface 11 using an electric circular saw. Put in. Each of the cuts 19A to 19D has a constant depth from the end face 11. The four cuts 19A to 19D are connected to each other at the central portions 14a and 17a of each side, and the central axis of the cut end surface 11 when viewed from a direction perpendicular to the cut end surface 11. A diamond-shaped annular groove surrounding C is formed.
As the means for forming the notches 19A to 19D, it is preferable to use a circular saw that is a power saw, particularly a stationary circular saw, as in the first embodiment.

Also in the first reference aspect, for example, in each cross section (cross section orthogonal to the longitudinal direction) at the site P1 where the bottoms of the cuts 19A to 19D are located and the position P2 in FIG. While the portion near the notch 19 is dried relatively quickly, the portion far from the notch 19 is dried later than the portion near the notch 19.
According to the first reference aspect, in this way, by generating a portion having a high moisture content and a portion having a low moisture content in the same cross section, the annual ring direction generated when the same cross section in the longitudinal direction dries at the same speed. The tension can be alleviated and the occurrence of internal cracks can be suppressed. Moreover, by preventing the crack which generate | occur | produces in the vicinity of a mouth end surface, the crack which a crack progresses and advances to the longitudinal direction center part side of a timber is suppressed similarly. Thereby, dry wood without internal cracks and dry wood with few internal cracks are obtained.

From the viewpoint of preventing internal cracks, each of the cuts 19A to 19D preferably has a depth L5 (see FIG. 5) from the end surface 11 of 5 to 300 mm, particularly 10 to 100 mm. The depth L5 is preferably 5 to 300%, particularly 10 to 100% of the distance L3 between the side surfaces 14 and 14 and / or the distance L4 between the side surfaces 17 and 17.
Moreover, it is preferable that the width W [refer FIG. 5] of the notches 19A-19D is 1-10 mm, respectively, especially 2-6 mm.

In the second reference embodiment, slit-shaped perpendicular to the respective mouth end surfaces 11 are formed on both end surfaces 11 (only one of them is shown) at both ends in the longitudinal direction of the wood 10 'which is a cored square member as shown in FIG. Cuts 19 and 19 are made to obtain a wood to be dried 10D (10) shown in FIG. More specifically, both sides of the wood 10 'sandwiching the central axis C of the end face 11 are linearly cut to a predetermined depth using an electric circular saw. The cuts 19 and 19 are formed in parallel to each other, and each of the cuts 19 and 19 is narrowly opened in the end face 11 and extends between the side faces 17 and 17.
As the means for forming the notches 19, 19, it is preferable to use a circular saw that is a power saw, particularly a stationary circular saw, as in the first embodiment.

Also in the second reference mode, for example, in the portion P1 where the bottom of the cut 19 is located in the longitudinal direction of the wood to be dried 10D and the position P2 in FIG. On the other hand, the part far from the notch 19 proceeds later than the part close to the notch 19.
According to the second reference aspect , in this way, by generating a portion having a high moisture content and a portion having a low moisture content in the same cross section, the annual ring direction generated when the same cross section in the longitudinal direction is dried at the same speed. The tension can be alleviated and the occurrence of internal cracks can be suppressed. Moreover, by preventing the crack generated in the vicinity of the mouth end surface, the crack generated by the progress of the crack toward the central portion in the longitudinal direction is similarly suppressed. Thereby, dry wood without internal cracks and dry wood with few internal cracks are obtained.

  From the viewpoint of preventing internal cracks, it is preferable that the notches 19 and 19 have a depth L6 (see FIG. 6) from the end surface 11 of 5 to 300 mm, particularly 10 to 100 mm. The depth L6 is preferably 5 to 300%, particularly 10 to 100% of the distance L3 between the side surfaces 14 and 14 and / or the distance L4 between the side surfaces 17 and 17.

Further, in the slit-shaped cuts 19 and 19, a distance L7 from the surface of the side surfaces 14 and 14 to the cut (see FIG. 6) is 5 to 45% of the distance L3 between the side surfaces 14 and 14, particularly 20 to 20%. It is preferably 40%.
Moreover, it is preferable that the width W [refer FIG. 6] of the notches 19 and 19 is 1-10 mm, respectively, especially 2-6 mm.

In the third embodiment, the vicinity of both ends 26 (only one is shown) at both ends in the longitudinal direction of the wood 10 ', which is a cored square member as shown in FIG. 3, is cut into a block shape and shown in FIG. To-be-dried wood 10E (10) is obtained.
More specifically, as shown in FIG. 5 using an electric circular saw, slit-like cuts 19A to 19D perpendicular to the respective end surfaces 11 are made, and similarly, using the electric circular saw, the wood 10 The corners on the circumferential surface of 'are cut in the direction of the central axis of the wood 10' to remove the four corners surrounding the central axis C of the wood 10 'in the vicinity of the mouth end surface of the wood 10'. The part to be removed has a right triangular prism shape. The triangular prism-shaped block may be removed by making cuts 19 </ b> A to 19 </ b> D perpendicular to the end face 11 after cutting the corners on the peripheral surface of the wood 10 ′. Further, instead of the electric circular saw, another cutting means may be used.

  In the obtained wood to be dried 10E, there are four triangular cut surfaces 12, 12,... Substantially parallel to the cut end surface 11 and in the vicinity thereof, and a cut end surface from the position P1 of the cut surface 12. The protrusion part 13E which protrudes to 11 side has arisen. The protrusion 13E has a square or rhombus cross section orthogonal to the longitudinal direction of the wood, and the diagonal of the cross section is inclined 45 degrees with respect to the diagonal of the cross section of the to-be-dried wood 10E at a portion other than the protrusion 13E. ing.

Also in the third embodiment, since the cut surfaces 12, 12,... Are generated at positions separated from the distal end surface 13a (the end surface 11) of the protrusion 13E, for example, at the position P1 of the cut surfaces 12, 12,. In the artificial drying, the moisture content of the cut surface 12 starts to decrease immediately, whereas the region 18 surrounded by the cut surface 12 is unlikely to evaporate moisture due to the presence of the protrusion 13E. The decrease in the moisture content at 18 proceeds later than the cut surfaces 12, 12. In addition, also at the position P2 in FIG. 7 , the drying of the portion overlapping the protruding portion 13E proceeds later than the portion overlapping the cut surfaces 12 and 12.
According to the third embodiment, in this way, by causing a high on the water content and low areas in the same cross-section, the annulus direction which occurs when the longitudinal direction of the same section to dry at a similar rate The tension can be alleviated and the occurrence of internal cracks can be suppressed. Moreover, by preventing the crack generated in the vicinity of the mouth end surface, the crack generated by the progress of the crack toward the central portion in the longitudinal direction is similarly suppressed. Thereby, dry wood without internal cracks and dry wood with few internal cracks are obtained.

From the viewpoint of preventing internal cracks, the distance L1 (see FIG. 7 , same as the protruding length of the protruding portion 13E) from the front end surface 13a (the end surface 11) of the protruding portion 13E to the cut surfaces 12, 12,. It is preferable that it is -300mm, especially 10-100mm. The distance L1 is preferably 5 to 300%, particularly 10 to 100% of the distance L3 between the side surfaces 14 and 14 and / or the distance L4 between the side surfaces 17 and 17.

  Further, the total area of the cut surfaces 12, 12,... Is 10 to 80%, particularly 30 to 60% of the total area of the cross section (cross section orthogonal to the X direction) of the wood to be dried 10E in the portion other than the protruding portion 13E. Preferably there is.

In the dry wood manufacturing method of the present invention, predetermined processing for preventing internal cracks in the wood surface to be dried (wood to be dried) or the vicinity of the wood surface, for example, FIG. 2, FIG. 4 or FIG. Artificial drying is performed after processing as shown in FIG.
Dry wood obtained by artificial drying can be used for various purposes, and is particularly preferably used as a structural material such as a pillar material, a beam material, or a base material in a wooden building such as a wooden house.

  The dried wood obtained by drying can be used as it is for various applications. For example, it is also preferable to cut off unnecessary portions near the longitudinal ends of the wood.

For example, the dry wood obtained by drying the wood to be dried shown in FIG. 2 is a dry wood at a position slightly in the center of the wood longitudinal direction from the position of the slit-shaped cuts 15 and 16 and at the positions of the cut surfaces 12 and 12. Can be used as wood having no protruding portion at the end. Moreover, it can also cut out the end surface and side extension part 13B, 13B of the protrusion part 13, and can also use as lumber (column material etc.) which has protrusion parts, such as a tenon, in an edge part.
Moreover, the dry wood obtained by drying the to-be-dried wood shown in FIG. 4 and FIG. 7 is also made of dry wood at a position slightly longer than the position of the cut surface 12 and at the center of the wood longitudinal direction or at the positions of the cut surfaces 12 and 12. It can be used as wood that is cut perpendicularly to the longitudinal direction and does not have protrusions at the ends. Further, the end surface of the protruding portion 13, the whole or a part of the peripheral surface of the protruding portion 13, and / or the cut surface 12, etc. are cut to a predetermined thickness, and the wood (column material) having a protruding portion such as a tenon at the end portion Etc.).

  Moreover, the dry wood obtained by drying the to-be-dried wood shown in FIG. 5 and FIG. 6 has the position in the longitudinal direction of the dry wood slightly different from the position of the center of the wood longitudinal direction from the position of the bottom of the slit-shaped cut 19. Or a portion located outside the four slit-shaped cuts 19A to 19D and a portion sandwiched between the two slit-shaped cuts 19, 19 Can also be used. In that case, the part surrounded by the four slit-like cuts 19A to 19D and the part sandwiched between the two slit-like cuts 19 and 19 are the entire end face or the peripheral surface of the projecting part or It can also be used as wood (column material or the like) having a projecting portion such as a tenon at an end portion.

In the first to third embodiments and the first and second reference modes , the cut end or the cut in the vicinity thereof and the artificial drying in that state are smooth. Even a non-smooth surface cut with a chain saw, for example, can be performed without problems. Moreover, the cut and the cut formation of the end face 11 or the vicinity thereof in the first to third embodiments and the first and second reference embodiments are also suitable for automation by a machine on a lumber line. For example, in the processing shown in FIG. 2, a pair of upper and lower circular saws are arranged at the passing positions in the lumber line in the vicinity of both ends of the wood to be processed, and the wood to be processed is slid on the table, or a conveying roller or belt It is possible to easily form slit-like cuts as shown in FIG. 2 on the two opposite side surfaces of the wood to be processed by being moved by a conveying means such as a conveyor and introduced between the pair of circular saws. it can.

As mentioned above, although preferred embodiment of this invention was described, each invention is not restrict | limited to said embodiment, It can change suitably.
For example, different forms of crack prevention processing may be applied to one end and the other end of one piece of wood 10 '.

Further, in the first embodiment, the slits 15 and 16 toward the central axis C are formed on the two opposite side surfaces 14 and 14 of the wood 10 'to form the protruding portion 13 and the cut surface 12, but FIG. A slit-like cut toward the central axis C may be made in each of the four side surfaces 14, 14, 17, and 17, as in the dry wood 10F (10) shown in FIG. The cuts formed in the side surfaces 17 and 17 have the same configuration as the cuts 15 and 16 described in the first embodiment, and have a constant depth L9 along the Y direction.
In the example shown in FIG. 8, the cuts on the side surfaces 17 and 17 are formed at the same positions as the cuts 15 and 16 formed on the side surfaces 14 and 14 in the longitudinal direction of the wood 10 ′. The cut surface formed by the cuts (the cut surface on the longitudinal center side of the wood) is continuous with the cut surfaces 12 formed by the cuts 15 and 16 formed on the side surfaces 14 and 14. In this case, the region 18 surrounded by the continuous cut surface has a rectangular shape as viewed from the central axis direction, and the protruding portion 13 is continuous with the longitudinal direction of the wood 10F through the region 18.

In the example shown in FIG. 8, the region 18 has a square shape, but the region 18 may have a rectangular shape that is long in the Z direction. The ratio of the depth L9 of the cut formed in the side surfaces 17 and 17 to the distance L4 between the side surfaces 17 and 17 is the same as the ratio of the depth L2 of the cuts 15 and 16 to the distance L3 between the side surfaces 14 and 14. It may be different or different.
Furthermore, the longitudinal position of the wood 10 ′ may be different between the cuts made in the side surfaces 17 and 17 and the cuts 15 and 16 put in the side surfaces 14 and 14. In addition, the width W of the cut may be different between the cuts made in the side surfaces 17 and 17 and the cuts 15 and 16 put in the side surfaces 14 and 14.
As described above, the slits 12 and the protrusions 13 are formed on the four side surfaces of the square bar by making slit-like cuts from the respective side surfaces toward the central axis C of the square bar. can get.

Further, in the second embodiment, the portions located on both sides sandwiching the central axis C in the vicinity of the woodworking surface 11 of the wood 10 ′ are removed to produce the cut surface 12 and the protruding portion 13, but the third embodiment As shown in FIG. 9 and the to-be-dried wood 10G (10) shown in FIG. It may be generated.
In the to-be-dried wood 10G shown in FIG. 9, the part located in the four directions surrounding the central axis C is removed, and the prism-shaped protrusion part 13 which has four side surfaces parallel to each of the four side surfaces of the square 10G is produced. . The portion outside each of the four side surfaces of the protruding portion 13 may be removed first from any portion. For example, the vicinity of the side surfaces 14 and 14 of the wood 10 ′ is removed, and the covering shown in FIG. After making it into the state of dry wood 10B (10), the vicinity of the side surfaces 17 and 17 is removed.

  In the example shown in FIG. 9, the cutting positions of the side surfaces 17, 17 in the longitudinal direction of the wood are the same as the cutting positions of the side surfaces 14, 14, and a continuous annular cutting surface 12 is provided around the protrusion 13. Has occurred. In the example illustrated in FIG. 9, the cross-sectional shape perpendicular to the axial direction of the protruding portion 13 is a square shape, but the cross-sectional shape of the protruding portion 13 may be a rectangular shape that is long in the Z direction. Further, the length L2 or the length L9 may be different on both sides of the central axis C.

Further, in the second reference embodiment, the two cuts 19 and 19 are formed between the side surfaces 17 and 17 with the central axis C sandwiched between the cuff surface 11 of the wood 10 ′. Like the to-be-dried wood 10H (10) shown, in addition to the cuts 19 and 19, two cuts 25 and 25 may be formed so as to be orthogonal to the cuts 19 and 19. The notches 25 and 25 are also formed so as to sandwich the central axis C, and are formed in parallel to each other. Further, it is formed so as to cross the notches 19 and 19 and cover the entire area between the side surfaces 14 and 14. The depths of the cuts 25 and 25 may be the same as or different from the depths of the cuts 19 and 19.
The notches 25 and 25 have a ratio of the distance L10 from the surface of the side surfaces 17 and 17 to the notch distance L4 between the side surfaces 17 and 17 at a distance L7 from the surface of the side surfaces 14 and 14 to the notch L7. The ratio may be the same as or different from the ratio between the distances 14 and 14. Further, the width W may be different between the notch 25 and the notch 19.

Further, instead of forming the notches 19A to 19D in the first reference mode so that the adjacent notches intersect at the center of each side surface, the adjacent notches are predetermined from each side surface toward the central axis C side. It can also be formed so as to intersect at a position separated by a distance.

  Moreover, in each embodiment mentioned above, you may combine processing, such as apply | coating and inject | pouring conventionally the dimension stabilizers, such as a crack stopper and polyethyleneglycol.

In addition, the description omitted in one embodiment and the requirements of only one embodiment can be applied to other embodiments as appropriate, and the requirements in each embodiment can be appropriately applied between the embodiments. Can be substituted for each other. Moreover, the requirements in each embodiment can be interchanged with each other as appropriate.
Further, one end of one piece of wood 10 ′ may be in the form shown in FIG. 2, and the other end may be in any form of the forms shown in FIGS. 4 to 10. One end of 'may be configured as shown in FIG. 4, and the other end may be configured as any one of the configurations illustrated in FIGS. 5 to 10. In addition, one end of one piece of wood 10 ′ may be in the form shown in FIG. 5, and the other end may be in one of the forms shown in FIGS. 7 to 9 . one end of the 'while the embodiment shown in FIG. 6, the other end may be any one form of the embodiment shown in FIGS. 7-9.
In addition, one end of one piece of wood 10 'has the form shown in FIG. 2 or FIG. 4, while the other end has the form shown in FIG. 2 or 4 rotated 90 degrees around the center axis C of the wood. It can also be in the form.

In addition, a slit-shaped incision or a process for forming a protruding portion as shown in FIG. 4 or FIG. 7 can be replaced with a circular saw, using a joint processing machine, an NC router, etc. Two or more of these may be used in appropriate combination.
The wood 10 'is preferably a square in cross section, but may be a flat material or the like.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. However, the present invention is not limited to the examples.

[Drying test]
59 core-supported squares (columns, without splitting, cross-sectional dimensions 115 mm x 115 mm, length 300 cm) made from Tochigi cedar as the material to be dried using the drying apparatus having the configuration shown in FIG. About (the moisture content before drying 45-120%), it dried 5 times with the drying schedule shown below.
[Drying schedule]
Initial cooking process (96 ° C., 12 hours) → first drying process (dry bulb temperature 120 ° C., wet bulb temperature 90 ° C.) → second drying step (dry bulb temperature 110 ° C., wet bulb temperature 90 ° C.) → third drying Process (dry bulb temperature 100 ° C, wet bulb temperature 80 ° C) → fourth drying step (dry bulb temperature 90 ° C, wet bulb temperature 60 ° C)
The time for each step was changed as appropriate while monitoring the moisture content. FIG. 11 shows a typical example of each process.
Drying was performed with an average moisture content of less than 15%, and ended when the moisture content of the column material monitored by the moisture meter became less than 15%. Therefore, the drying time differs for each drying material lot, and was adjusted between 120 and 180 hours.

[Example 1]
The vicinity of each of the both ends of 11 undried cored squares was processed into the form shown in FIG. The dimensions of each part in FIG. 2 were a distance L1 = 50 mm (43% of the distance L3), L2 = 28 mm, and a width W = 2 mm.

[Example 2]
The vicinity of each of the both ends of 11 undried cored squares was processed into the form shown in FIG. The dimensions of each part in FIG. 4 were set such that the distance L1 = 50 mm (43% of the distance L3) and L2 = 28 mm.

[ Reference Example 1 ]
The slit-shaped cuts 19A to 19D having the form shown in FIG. 5 were made in both the front ends of the six undried cored square members. The dimensions of each part in FIG. 5 were L5 = 50 mm and the width W = 2 mm.

[ Reference Example 2 ]
The slit-shaped cuts 19 and 19 having the form shown in FIG. 6 were made in both the end surfaces of the five undried cored square members. The dimensions of each part in FIG. 6 were L6 = 50 mm, L7 = 28 mm (24% of L3), and width W = 2 mm.

[Example 3 ]
The vicinity of each of the both end surfaces of 11 undried cored squares was processed into the form shown in FIG. The dimensions of each part in FIG. 7 were a distance L1 = 50 mm (43% of the distance L3) and L8 = 81.3 mm.

[Comparative Example 1]
In the test lots of Examples 1 to 3 and Reference Examples 1 and 2 , 3 pieces of undried cored squares that are not processed on both the end surfaces of the both ends and in the vicinity thereof (total of 15 pieces) are added, It used for said drying test.

[Evaluation]
About the core support squares (59 in total) dried by the methods of Examples , Reference Examples and Comparative Examples, the moisture content and internal cracks were evaluated by the methods shown below, respectively, and samples with a moisture content of 20% or less were extracted. The results are shown in Table 1.

[Moisture content]
Moisture content after drying: A range of 100 to 150 mm was cut out from each end face of each end in the longitudinal direction of the square bar after drying to obtain a sample having a width of 50 mm. And after measuring the weight W1 of each sample, each sample is JIS Z2201. Test method for wood According to the method for measuring moisture content, the sample was left at 105 ° C. in a dryer, and the weight W2 after the sample reached a constant weight was measured. The water content after drying was determined by the following formula (2).
Water content after drying (%) = (W1−W2) / W2 × 100 (2)

[Internal crack]
A cut surface at a position of 100 mm (two places) was observed from both ends of the square bar after drying, and the degree of internal cracks observed in each cross section was judged according to the following evaluation criteria, and internal crack evaluation was performed.
Specifically, from each dry wood, two samples, a sample at the front end and a sample at the end, are obtained, and for each sample , each reference example or comparative example, a sample having a moisture content of 20% or less. The ratio of the number of samples that passed the internal crack (“pass” in the table) to the total number of samples (“test body” in the table) [(passed / test body) × 100] was obtained, and this was regarded as the pass rate. It is shown in the column of “less than 20% water content”. The sample having passed the internal crack is a sample having an evaluation of “none” or “small” according to the following evaluation criteria.
In addition, samples having a moisture content of 20% or less are classified into samples having a moisture content of less than 10% and samples having a moisture content of 10% or more but less than 20%. In Table 1, the “water content of less than 10%” and “water content of 10% or more and less than 20%” columns are shown.
In this example, “moisture content of less than 10%” means an overdried material, “moisture content of 10% or more but less than 20%” means a suitable desiccant, and “moisture content of less than 20%” passes as a desiccant. It means that.

〔Evaluation criteria〕
None: No cracks are observed.
Small: There is a crack having a maximum width of 1 mm or less and a length of 20 mm or less.
Medium: A crack that does not correspond to a small crack, and has a maximum crack surface width of 2 mm or less and a length of 50 mm or less.
Large: There is a crack having a maximum width exceeding 2 mm or a length exceeding 50 mm.

Moreover, the pass rate value in the column of “moisture content of less than 20%” is not less than the value of Comparative Example 1 and 50% or more, and the pass rate value is not less than the value of Comparative Example 50. Those less than% were marked with ◯, and are also shown in Table 1 as a comprehensive evaluation.

  From the results shown in Table 1, it can be seen that, according to the method of the present invention, the internal cracks in the dry wood can be significantly reduced as compared with Comparative Example 1 (conventional method). In addition, the drying method of the dry wood of this invention is especially effective when drying until the moisture content of the pillar material after drying becomes 20% or less, especially 15% or less.

10, 10A to 10H Dry wood (after internal crack prevention processing)
11 Cut end 12 Cut surface 13, 13E Protrusion 19, 19A-19D, 25 Notch

Claims (4)

  Manufacture of dry wood to be artificially dried after cutting the vicinity of the end face of the wood to produce a cut surface substantially parallel to the end face and a protruding portion protruding from the position of the cut face to the end face side. Method.   The wood is a square bar, and a slit-like cut toward the central axis of the square bar is formed on each of the four side surfaces or two opposite side surfaces of the square bar to generate the cut surface and the protruding portion. The method for producing dry wood according to claim 1.   The dry wood according to claim 1, wherein the wood is a square wood, and the portions located on both sides sandwiching the central axis of the square wood in the vicinity of the wood lumber surface of the square wood are removed to generate the cut surface and the protruding portion. Manufacturing method.   2. The drying according to claim 1, wherein the wood is square wood, and a portion located in four directions surrounding the central axis of the square wood in the vicinity of the wood lumber surface of the square wood is removed to produce the cut surface and the protrusion. Wood manufacturing method.

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