JPH065907U - Square bar with split groove - Google Patents

Abstract

(57) [Summary] [Purpose] The present invention relates to a timber having a split groove for preventing cracks and dimensional deviation due to drying of wood. [Structure] A vertical split groove 2 having a depth of 10 to 30 mm is formed at the center in the longitudinal direction on the entire surface of three sides or four sides of a square bar 1. [Effect] By maintaining the mechanical balance due to drying shrinkage, the deviation is minimized and the cosmetic surface is not damaged.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 TECHNICAL FIELD The present invention relates to a column square bar having a split groove for preventing cracks and dimensional deviation due to drying of wood.

[0002]

[Prior art]

 Cedar, rice hemlock, and cypress are used for large-walled pillars. These decorative pillar materials are provided with deep cuts called the back slits that reach the core of the pillars, and the back splits shown in Figs. 3 and 4 have been used for the purpose of preventing cracks on the surface of the decorative pillars. Has been done. The untreated pillars shrink due to drying and irregular vertical cracks occur on the surface (shown in FIG. 8). The back split is provided to prevent the product value from being significantly impaired by cracks caused by drying shrinkage, and to prevent the cosmetic surface from cracking and cosmetic properties being damaged after construction. However, as will be described in detail later, this back splitting technology actually causes a large deviation from the purpose due to drying after building construction, which causes waviness on the wall material or a decorative surface other than the back splitting surface. It is known that cracks frequently occur in the (Fig. 7). The idea that "wood is crazy" has become common sense. However, in recent years, along with the spread of prefabricated houses and other factory-produced houses, pre-cut products with accurate dimensions have been rapidly spread, and it has become impossible to deal with the conventional wisdom. It is becoming mainstream.

During the lumbering of cored timber, when the water content falls below 30%, the cracks in the back cracking greatly open (water content is 25% or less according to JAS standard), and when the water content is 20% or less, pillars Since the cross section of the trapezoid becomes like a trapezoid (shown in (b) of Fig. 4), the hem of the trapezoid is corrected and ground to adjust the right angle and dimensions before shipment (shown in (c) of Fig. 4). It is shipped as a timber product. However, after that, it absorbs moisture from the outside air, and the cracks in the open back splitting close it, and the cross-section transforms into a trapezoid (shown in (d) in Fig. 4) that is the reverse of the trapezoid. In this case as well, the product value will decrease. If cracks occur, the commercial value of the pillar material will be impaired, and if cracks or deviations occur after the construction, it was unlucky and I had no choice but to repair it.

[0004]

[Problems to be solved by the device]

 The present invention has been made in view of such a conventional situation, and provides a pillar material capable of minimizing the deviation due to drying without causing a crack on the decorative surface.

[0005]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the present invention forms a longitudinal split groove 2 having a depth of about 10 to 30 mm in the longitudinal center of three or four surfaces of a cored square bar 1.

[0006]

【Example】

 The present invention will be described with reference to the embodiments of the drawings. As shown in FIG. 1, a width of 105 mm square cedar cored timber 1 should be straight in the longitudinal center of the other three surfaces while avoiding the beautiful one surface. A vertical groove 2 having a depth of 3 mm and a depth of 15 mm is formed. This split groove 2 is intended to guide the crack into the split groove 2 and prevent it from occurring outside the split groove 2. It is necessary to vertically install the split groove 2 at the center of the column surface where cracks are most likely to occur. If it approaches the corner, a crack will occur at the center of the column surface avoiding the split groove 2. The depth of the split groove is preferably 10 to 30 mm, and even if the depth is 40 mm, for example, the effect of guiding the split into the split groove 2 is great, but the split becomes unnecessarily large and the deviation becomes large. By providing the split groove 2 on the three surfaces of the cored square bar 1, the other surface can be secured as a decorative surface without damaging the split groove 2 or the like.

Further, as shown in FIG. 2, a vertical split groove 2 having a width of 3 mm and a depth of 20 mm is formed in a straight line at the center of the entire four faces of a cedar cored square bar 1 of 110 mm square. In this case, it is used as a structural member, not as a decorative material, in a wall or the like without appearing on the surface.

[0008]

[Action]

 The present invention has the above-mentioned configuration and is an efficient and effective processing in consideration of the mechanical balance due to the drying of wood. The conventional spine splitting technology (shown in (a) of FIGS. 3 and 4) Is to prevent the occurrence of cracks on other surfaces by inserting a single vertical crack into the core. However, in this case, one large back split may concentrate the drying shrinkage change of the wood on one side and lose the mechanical balance, resulting in the loss of the purpose of not impairing the original cosmetic appearance, Furthermore, it has been pointed out that it is difficult to expand the madness. On the other hand, in the present invention, the vertical split groove 2 having a depth of about 10 to 30 mm is formed on three or more surfaces without cutting the core to a large extent, so that the mechanical balance is not lost due to drying shrinkage and the deviation is minimized. It was devised based on the idea that it would be kept down and that the makeup would not be damaged. When the vertical groove 2 is formed in a straight line at the center of the three surfaces, the shrinkage is well balanced and divided into three directions, so that the burden of shrinkage on the decorative surface is reduced and cracks do not appear. Even when the contraction is large, the contraction change is divided into three directions, and as shown in FIGS. 5 and 6, the split groove 2 positively generates a crack 3 therein, and the crack is concentrated in a weak place. Therefore, the shrinkage force of the portion other than the vertical groove 2 is reduced, and the generation of cracks is suppressed even on the decorative surface without the groove 2.

[0009] When an undried wood was processed with a split groove 2 having a depth of 15 mm and subjected to a natural drying test, as shown in (b) of FIGS. 5 and 6, most of the vertical split groove 2 was obtained at a water content of 16%. A split 3 occurred in the back. However, no cracks were generated in the parts other than the split groove 2. Regarding the depth of this groove, it was confirmed that even if it was about 5 mm, the effect of cracks appearing in the vertical groove 2 was found, but in many cases, cracks may protrude in addition to the vertical groove 2, and the cosmetic properties are poor. Damaged. Further, since the final cutting is carried out by about 2 to 3 mm, it may become partially shallow at about 5 mm, and it is actually necessary to leave 10 mm or more to leave the groove. Also, it was confirmed that if the depth is about 30 mm, there is a sufficient guide effect for cracks, and the effect is great even if a depth greater than this is provided, but there is a tendency for the grooves to unnecessarily expand too much, It tends to be unnecessarily large. It is preferable that the decorative surface does not crack, and it is preferable that the groove (scratch) is as shallow as possible. In that sense, about 30 mm is sufficient, and more than 30 mm is not preferable. When the split groove is provided on two surfaces (shown in FIG. 9), the effect of preventing cracking of the remaining decorative surface is not exhibited at a depth of about 30 mm.

When grooves are provided on all four surfaces, the decorative surface disappears, but more reliable crack prevention is achieved, and even if cracks occur, the overall balance can be broken, so there is very little deviation from the overall pillar. Since the deviation is extremely small, when the surface plate material is directly applied, it is possible to prevent the occurrence of waviness on the finishing wall surface.

[0011]

[Effect of device]

 As described above, efficient processing is performed in consideration of the mechanical balance due to the drying of wood, and it is possible to minimize the deviation by maintaining the mechanical balance due to drying shrinkage without inserting a large back split to the core. Suppresses and does not spoil the makeup. When the vertical groove 2 is formed in the center of the three surfaces, the shrinkage is balanced in three directions and the burden of shrinking on the other surfaces is reduced, so that the decorative surface is not damaged. If the split groove 2 is provided on all four sides, the decorative surface will be lost, but it will more reliably prevent cracking, but it can be used not as a decorative material but as a structural material without deviation, and there is little deviation, so it is a surface plate material directly. In case of passing, no waviness is generated on the wall surface. This solid timber will rapidly spread as the main product of precut timber.

[Brief description of drawings]

FIG. 1 is a perspective view of a trihedral groove of the present invention.

FIG. 2 is a perspective view of a quadrant groove of the present invention.

FIG. 3 is a perspective view of a conventional split column material.

FIG. 4 shows a conventional back splitting pillar material, (a) is a plan view immediately after back splitting processing, (b) is a plan view showing a dried state after back splitting processing, and (c) is a plan view immediately after correction processing. The plan view, (d) is a plan view in a state of absorbing moisture after the correction processing.

FIG. 5 is a plan view of a trihedral grooved column material, (a) is a plan view of a trihedral grooved column material, showing a state in which a dry crack has occurred after the dicing groove processing of the present invention.

6A and 6B are plan views of the split groove of the present invention immediately after the split groove is processed, and FIG. 6B is a plan view of a state where the split groove is dried and a crack is formed in the split groove.

FIG. 7 is a perspective view showing a cracked state of a conventional back split.

FIG. 8 is a perspective view showing a cracked state without spine split processing.

FIG. 9 is a perspective view showing a cracked state in the dicing groove processing.

[Explanation of sign]

 1 Core with core 1a Column surface 2 Split groove 3 Split 4 Back split

Claims (1)

[Scope of utility model registration request] 1. A cored square bar with a split groove, characterized in that a vertical split groove (2) having a depth of about 10 to 30 mm is formed in the longitudinal center of three sides or four sides of the square bar (1).