Building board

Abstract

To provide a building board that enables a joint to be inconspicuous when forming a wall body by arranging and joining multiple building boards.SOLUTION: A building board 1 comprises groove parts 21 extending in a longitudinal direction D1 and forming recess parts where at least one part is constituted of curved surfaces 21A, 21B, flat parts 22 placed at an end part 21A1 side and an end part 21B1 side of the groove part 21 in a vertical direction D2 and extending in the longitudinal direction D1, and projecting parts 30, 40 formed within the groove part 21 and extending in the longitudinal direction D1.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a building board for forming a wall or the like of a building. [Background technology]

[0002] Patent Document 1 describes a building board that has protrusions in the joints to maintain the three-dimensional appearance of the surface of the building board while preventing breakage when the builder transports the building board. The building board described in Patent Document 1 has protrusions formed in the vertical grooves to prevent the building board from breaking along the vertical joints. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-137662 Summary of the Invention [Problem to be solved by the invention]

[0004] However, with the building boards described in Patent Document 1, when multiple building boards are lined up and joined to form a wall, even if protrusions are provided in the joints, the three-dimensionality of the surface of the building boards may not be maintained.

[0005] To provide a building board which, when a wall is formed by arranging and joining a plurality of building boards, can provide protrusions in the joints and maintain the three-dimensional appearance of the surface of the building board. [Means for solving the problem]

[0006] According to a first aspect of the present invention, there is provided a building board having a design surface on its surface and being rectangular in plan view, the building board comprising: a groove portion extending in a first direction along one side of the building board and having an inner surface at least partially composed of a curved surface; a rib portion located between the groove portions of the building board and extending in the first direction; and a protrusion formed within the groove portion and extending in the first direction, the protrusion including: a first protrusion having a first plane extending from one of the one end side and the other end side of the groove portion to the other side; a second plane inclined downward from the end of the other side of the first plane and contacting the other side of the groove; a third plane not adjacent to the upper end of the groove portion and extending inclined upward from one of the one end side and the other end side of the groove to the other side; and a fourth plane inclined upward from the other side of the groove portion to one side. In addition, the bottom of the groove portion has a bottom surface parallel to the back surface of the wall, and the angle formed by a virtual plane that is in contact with the bottom surface and parallel to the plane forming the rib portion and a first plane that is parallel to the virtual plane is smaller than the angle formed by the virtual plane and the second plane, and the third angle formed by the virtual plane and the third plane is different from the fourth angle formed by the virtual plane and the fourth plane. In the building board of the first aspect of the present invention, when the building boards are joined in the second direction, the grooves and ribs extending in the first direction make it possible to make the joints between the building boards less noticeable. Furthermore, since the grooves are at least partially curved, they create a rich sense of shadow. Furthermore, since protrusions are formed within the grooves, the grooves appear deeper than their actual size.

[0007] In the building board of the second aspect of the present invention, a plurality of first protrusions and second protrusions are formed on the design surface, and each of the first protrusions and second protrusions is randomly arranged on the design surface. This makes it possible to make the misalignment of the grooves in the second direction less noticeable when the building boards are joined in the first direction.

[0008] In a third aspect of the building board of the present invention, a plurality of first protrusions and second protrusions are formed on the design surface, the width of the first plane of the first protrusions in the second direction is formed wider than the width of the second plane in the second direction, and at least some of the first protrusions among the plurality of first protrusions have unevenness formed on the surface of the first plane. This makes it possible to make the misalignment of the grooves in the second direction less noticeable when the building boards are joined in the first direction.

[0009] In the building board of the fourth aspect of the present invention, the upper limit of the second angle is preferably 70°.

[0010] In the building board of the fifth aspect of the present invention, when the third angle is greater than the fourth angle, the upper limit of the third angle is preferably 70° and the upper limit of the fourth angle is preferably 20°, and when the third angle is less than the fourth angle, the upper limit of the third angle is preferably 20° and the upper limit of the fourth angle is preferably 70°. As a result, the groove is at least partially formed of a curved surface, which enhances the sense of shadow. Furthermore, since the protrusion is formed within the groove, the groove appears deeper than its actual size.

[0011] In the building board of the sixth aspect of the present invention, it is preferable that the first protrusions and the second protrusions are formed in a plurality on the design surface, and the first planes of at least some of the plurality of first protrusions are formed parallel to the plane forming the rib portion. This makes it possible to make the deviation of the grooves in the second direction less noticeable when the building boards are joined in the first direction.

[0012] In a seventh aspect of the present invention, the building board has a plurality of grooves formed on the design surface, at least some of which are through grooves extending from one end to the other end of the design surface in the first direction, and a plurality of protrusions formed on the design surface, at least some of which are formed at the ends of the through grooves. This makes it possible to make the misalignment of the grooves in the second direction less noticeable when the building boards are joined in the first direction.

[0013] In the building board of the eighth aspect of the present invention, multiple rib portions are formed on the design surface, and it is preferable that grooves are formed on the surface of at least some of the multiple rib portions and that the surface is uneven.

[0014] In the ninth aspect of the present invention, the building board has a joint formed by joining on the upper and lower end faces in the first direction, and the lower end face preferably has a rib portion and the upper end face preferably has a groove portion, which makes the joint in the first direction less noticeable when the building board is installed. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a plan view of a building board according to an embodiment of the present invention. [Figure 2] FIG. 2 is a side view of the building board of FIG. [Figure 3] 3 is an enlarged side view of a protrusion formed in one groove portion included in FIG. 2. FIG. [Figure 4] 4 is an enlarged side view of a first protrusion and a second protrusion formed in a groove different from the groove in FIG. 3. FIG. [Figure 5] 4 is an enlarged side view of a second protrusion formed in a groove different from the groove in FIG. 3. FIG. [Figure 6] FIG. 3 is an enlarged side view of the protrusion included in FIG. 2(Z). DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, embodiments of the present application will be described in detail with reference to the drawings. In Figure 1, the right direction in the horizontal left-right direction D1 is labeled "right," the left direction is labeled "left," the up direction in the vertical up-down direction D2 is labeled "up," and the down direction is labeled "down." In Figure 1, the front of the paper is the front, the back of the paper is the back, and the direction perpendicular to the left-right direction D1 and the up-down direction D2 is the front-back direction D3. The directions shown in Figure 2 and subsequent figures are labeled to correspond to Figure 1. The building board 1 according to this embodiment is, for example, an exterior wall material for forming the exterior walls of a building. The building board 1 is a substantially rectangular building board, and in this embodiment, it is a horizontally long rectangle. The building board 1 is made of a ceramic material produced by press-molding raw materials such as cement. The size of the building board 1 is, for example, approximately 3030 mm in width and approximately 455 mm in length. The width and length are not limited to these dimensions. For example, the width can be selected within a range of approximately 1800 to approximately 3030 mm, and the length can be selected within a range of approximately 455 to approximately 1000 mm. The thickness of the building board 1 (distance in the front-to-back direction D3) is, for example, 14 to 30 mm.

[0017] The building board 1 has, for example, a top-bottom joint structure. The building board 1 has a lower solid portion 60 that protrudes upward from the back side of the upper end surface 11 of the building board 1 as a joint where the building board 1 is overlapped with an adjacent building board 1 above in the vertical direction D2. The building board 1 also has an upper solid portion 50, the back side of which is recessed at the lower end surface 12 of the building board 1, as a joint portion where the building board 1 can be overlapped with an adjacent building board 1 below.

[0018] With this configuration, adjacent building boards 1 in the vertical direction D2 are joined by overlapping the upper solid portion of the upper building board 1 with the lower solid portion of the lower building board 1. The joining of the upper and lower building boards 1 can also be performed using caulking material or metal fittings.

[0019] The building boards 1 do not have joints on the left side surface 14 and the right side surface 13. When joining building boards 1 in the left-right direction D1, the right side surface 13 of the left-side building board 1 and the left side surface 14 of the right-side building board 1 are joined using a sealant. However, the left side surface 14 and the right side surface 13 may also be configured to have solid parts (joints) extending in the left-right direction, forming a left-right joint structure.

[0020] As shown in FIGS. 1 and 2, the building board 1 has a design surface 2 on the front side and a back surface 3 which is a flat plane on the back side. The design surface 2 is the outer surface when the building board 1 is installed, and is the part that constitutes the pattern or design of the building board 1. In this embodiment, the design surface 2 occupies the area from the end of the surface side of the lower surface 12 to the end of the surface side of the upper surface 11 in the up-down direction D2, and occupies the area from the end of the surface side of the left surface 14 to the end of the surface side of the right surface 13 in the left-right direction D1. In this embodiment, the entire front surface of the building board 1 is the design surface 2, but a part of the front surface may be the design surface 2.

[0021] A plurality of grooves 21 (14 in FIG. 2) extending in the left-right direction D1 are formed on the design surface 2. In the present embodiment shown in FIG. 1, each groove 21 penetrates from the left side surface 14 to the right side surface 13 of the design surface 2 in the left-right direction D1, but this is not limiting and each groove 21 may be formed in a part of the left-right direction D1. The configuration of the groove portion 21 will be described with reference to FIGS. 3(a) is a view of the groove portion 21 as seen from the side of the building board 1, taken along the arrows in FIG. 1X-X, showing the lower solid portion 60, and is a diagram for explaining the side shape of the design surface 2, such as the groove portion 21. For this reason, FIG. 3 shows only the side shape of the design surface 2, and does not show parts other than the above-mentioned lower solid portion 50 and upper solid portion 60 that make up the design surface 2. FIG. 3(b) is a side view of FIG. 3(a) from which a first protruding portion 30 and a second protruding portion 40, which will be described later, have been removed. Fig. 3(c) is a diagram in which only the first protrusion 30 is extracted from the side view of Fig. 3(a). In Fig. 3(c), when two first protrusions 30 are formed in one groove 21, the first flat protrusion 30A formed on the left side is shown on the upper side, and the first flat protrusion 30B formed on the right side is shown on the lower side. Fig. 3(d) is a diagram showing only a first inclined protrusion 40A (described later) extracted from the side view of Fig. 3(a), and Fig. 3(e) is a diagram showing only a second inclined protrusion 40B (described later) extracted from the side view of Fig. 3(a). As shown in Fig. 3(b), at least a portion of each groove 21 is formed by curved surfaces 21A, 21B. That is, each groove 21 has curved surfaces 21A, 21B at its upper and lower ends that are convex toward the rear surface. The rear-side ends of curved surfaces 21A and 21B are connected to a substantially flat bottom surface 21C.

[0022] Additionally, adjacent groove portions 21 in the up-down direction D2 are connected via rib portions 22. Similar to the groove portions 21, the rib portions 22 extend in the left-right direction D1 and are formed on the design surface 2 from the right side surface 13 to the left side surface 14.

[0023] The upper end 22A of the rib portion 22 in the vertical direction D2 and the groove portion 21 are connected by the second curved surface 21B, and the lower end 22B of the rib portion 22 in the vertical direction D2 and the groove portion 21 are connected by the first curved surface 21A. The rib portion 22 includes a portion having V-shaped grooves (hereinafter referred to as "V grooves") 23A, 23B formed on its flat surface, and a portion having no V grooves 23A, 23B. Furthermore, the V groove 23A is formed deeper than the V groove 23B. Hereinafter, the deep V groove 23A will be referred to as groove 23A, and the shallow V groove 23B will be referred to as groove 23B. In other words, there are three types of rib portion 22: a portion without a V groove, a portion having groove 23A, and a portion having groove 23B. The position of each of these three types of rib portion 22 on the design surface 2 is determined randomly. In other words, the three types of rib portion 22 are not arranged on the design surface 2 according to any particular rule. Grooves 23A and 23B may be arranged regularly. Also, grooves 23A and 23B do not have to be provided on rib portion 22, or one type of V-groove or three or more types of V-grooves may be provided. Furthermore, the cross-sectional shape of the grooves formed in rib portion 22 is not limited to a V-shape, and may be an arc shape, an inverted trapezoid shape, or any other rectangular shape.

[0024] A plurality of types of protrusions extending in the left-right direction D1 are formed in the groove 21. As shown in Figures 3(c) to 3(e), the plurality of types of protrusions are roughly divided into first protrusions 30 and second protrusions 40. The first protrusion 30 is a protrusion having a first plane 31 and a second plane 32 that is inclined from one end of the first plane 31 in the up-down direction D2 toward the back surface 3. The first protrusion 30 is divided into a first flat protrusion 30A in which the first plane 31 is on the upper side in the vertical direction D2, and a second flat protrusion 30B in which the first plane 31 is on the lower side in the vertical direction D2.

[0025] Fig. 4 shows an enlarged side view of the first and second flat protrusions 30A, 30B and the first inclined protrusion 40A formed in the first groove 21 from the top in the up-down direction D2 in Fig. 3. As shown in Fig. 3(a), the first and second flat protrusions 30A, 30B and the first inclined protrusion 40A are formed in the same groove 21, and therefore appear to overlap in the side view. However, this makes it difficult to see the side shape of each protrusion, so in Fig. 3, each protrusion is shown separated.

[0026] 4, the first flat protrusion 30A has a first A plane 31A extending upward in the vertical direction D2 from a lower end 21B1 of the groove 21 (= an upper end 22A of the rib 22 in the vertical direction D2) and a second A plane 32A inclined from an upper end 31A1 of the first A plane 31A in the vertical direction D2 toward the back side in the front-to-back direction D3. The other end 32A2 of the second A plane 32A is in contact with the bottom surface 21C of the groove 21. In the illustrated example, an angle θ1A formed between an imaginary plane P that is in contact with the bottom surface 21C of the groove 21 and parallel to the flat surface constituting the rib 22 and the substantially parallel first A plane 31A is 0°. In the illustrated example, an angle θ2A formed between the imaginary plane P and the second A plane 32A is 60°.

[0027] On the other hand, the second flat protrusion 30B has a first B plane 31B extending downward in the vertical direction D2 from an upper end 21A1 of the groove 21 in the vertical direction D2 (= a lower end 22B of the rib 22 in the vertical direction D2), and a second B plane 32B inclined from a lower end 31B1 of the second B plane 31B in the vertical direction D2 toward the back side in the front-to-back direction D3. The other end 32B2 of the second B plane 32B is in contact with the second curved surface 21B of the groove 21. In the illustrated example, the angle θ1B between the imaginary plane P and the first B plane 31B, which is substantially parallel to the imaginary plane P, is 0°, and the angle θ2B between the imaginary plane P and the second B plane 32B is 60°.

[0028] As described above, in both the first and second flat protrusions 30A and 30B, the angles θ1A and θ1B are set smaller than the angles θ2A and θ2B. The widths of the flat surfaces 31A and 31B are set wider than the widths of the inclined surfaces 32A and 32B. Furthermore, at least some of the first-plane A surfaces 31A and first-plane B surfaces 31B of the multiple first protrusions 30 are provided with unevenness. To emphasize this unevenness, the widths of the first-plane A surfaces 31A and first-plane B surfaces 31B are set wider than the widths of the second-plane A surfaces 32A and second-plane B surfaces 32B, and the angles θ1A and θ1B formed between the first-plane A surfaces 31A and first-plane B surfaces 31B and the imaginary plane P are set smaller than the angles θ2A and θ2B formed between the second-plane A surfaces 32A and second-plane B surfaces 32B and the imaginary plane P.

[0029] The second protrusion 40 is a protrusion having an inclined surface 41 that extends at an angle from the back side to the front side in the front-back direction D3, and an inclined surface 42 that extends at an angle from the front side end of the inclined surface 41 to the back side. The second protrusion 40 is divided into a first inclined protrusion 40A in which the inclination of the inclined surface 41 is steeper than the inclination of the inclined surface 42, and a second inclined protrusion 40B in which the inclination of the inclined surface 41 is gentler than the inclination of the inclined surface 42. The first inclined protrusion 40A has a third A plane 41A that inclines toward the front side in the front-back direction D3 from a midpoint on the second curved surface 21B on the lower side in the up-down direction D2 of the groove 21, and a fourth A plane 42A that inclines toward the front side in the front-back direction D3 from a midpoint on the first curved surface 21A on the upper side in the up-down direction D2 of the groove 21. In the illustrated example, the angle θ3A formed between the imaginary plane P and the third A plane 41A is approximately 60°, and the angle θ4A formed between the imaginary plane P and the fourth A plane 42A is approximately 10°.

[0030] Fig. 4 shows an enlarged side view of the first and second inclined protrusions 40A, 40B formed in the second groove portion 21 from the top in the up-down direction D2 in Fig. 2. The first inclined protrusion 40A in Fig. 5 has the same configuration as the first inclined protrusion 40A in Fig. 4, and therefore a description of its configuration will be omitted.

[0031] 5, the second inclined protrusion 40B has a third B surface 41B that slopes toward the front side in the front-back direction D3 from a midpoint on the second curved surface 21B on the lower side in the up-down direction D2 of the groove 21, and a fourth B surface 42B that slopes toward the front side in the front-back direction D3 from a midpoint on the first curved surface 21A on the upper side in the up-down direction D2 of the groove 21. In the illustrated example, the angle θ3B formed between the imaginary plane P and the third B surface 41B is approximately 10°, and the angle θ4B formed between the imaginary plane P and the fourth B surface 42B is approximately 60°.

[0032] In this way, the angles θ3A and θ3B are set to different angles from the angles θ4A and θ4B. The cases where θ3A > θ4A and where θ3B < θ4B are illustrated. When θ3A > θ4A, it is preferable that the upper limit of the third angle θ3A is 70° and the upper limit of the fourth angle θ4A is 20°. When θ3B < θ4B, it is preferable that the upper limit of the third angle θ3B is 20° and the upper limit of the fourth angle θ4B is 70°.

[0033] As shown in Fig. 1, a plurality of protrusions 30, 40 are arranged on the design surface 2. The position of each of the plurality of protrusions 30, 40 on the design surface 2 is determined randomly. Of course, the protrusions may be arranged according to a predetermined rule rather than randomly. At least some of the plurality of protrusions 30, 40 are formed on the design surface 2 at the end of the groove 21 in the left-right direction D1.

[0034] As described above, the building board 1 of this embodiment is a building board 1 that has a design surface 2 on its surface and is rectangular in plan view, and includes a groove portion 21 that extends in the left-right direction D1 along one side of the building board 1 and forms a recess at least partially composed of curved surfaces 21A, 21B, ribs 22 that are located on the end 21A1 side and the end 21B1 side of the groove portion 21 in the up-down direction D2 along another side perpendicular to the one side of the building board 1 and extend in the left-right direction D1, and protrusions 30, 40 that are formed in the groove portion 21 and extend in the left-right direction D1. 40 is characterized by including a first protrusion 30 having a flat surface 31 extending from either one of the end 21A1 side or the end 21B1 side of the groove portion 21 to the other side, and an inclined surface 32 sloping downward from the end on the other side of the flat surface 31 and contacting the other side of the groove portion 21, and a second protrusion 40 having a first inclined surface 41 extending sloping upward from either one of the end 21A1 side or the end 21B1 side of the groove portion 21 to the other side, and a second inclined surface 42 extending sloping upward from the other side of the groove portion 21 to one side. In this way, when the building boards 1 of this embodiment are joined in the up-down direction D2, the grooves 21 and ribs 22 extending in the left-right direction D1 make it possible to make the joints between the building boards 1 less noticeable. Furthermore, since the grooves 21 are at least partially composed of curved surfaces 21A, 21B, a rich sense of shadow is created. Furthermore, since the protrusions 30, 40 are formed within the grooves 21, the grooves 21 appear deeper than their actual size.

[0035] Furthermore, the first protrusion 30 and the second protrusion 40 are formed in multiple numbers on the design surface 2, and each of the first protrusion 30 and the second protrusion 40 is arranged in multiple numbers on the design surface 2. As a result, when the building board 1 is joined in the left-right direction D1, the first protrusions 30 and second protrusions 40 formed in multiple numbers on the design surface 2 are arranged in multiple numbers on the design surface 2, making it possible to make the misalignment of the groove portion 21 in the up-down direction D2 less noticeable.

[0036] Furthermore, the first protrusions 30 and the second protrusions 40 are formed in multiple numbers on the design surface 2, the width of the flat surface 31 of the first protrusions 30 in the vertical direction D2 is formed wider than the width of the inclined surface 32 in the vertical direction D2, and the surface of the flat surface 31 of at least some of the multiple first protrusions 30 has unevenness formed thereon.

[0037] Furthermore, the first angle θ1 formed between the flat surface 31 and an imaginary plane P that is in contact with the bottom of the groove portion 21 and is approximately parallel to the plane that forms the rib portion 22 is smaller than the second angle θ2 formed between the imaginary plane P and the inclined surface 32, and the upper limit of the second angle is 70°, and the third angle θ3 formed between the imaginary plane P and the inclined surface 41 and the fourth angle θ4 formed between the imaginary plane P and the inclined surface 42 are different.

[0038] Furthermore, when the third angle θ3A is greater than the fourth angle θ4A, the upper limit of the third angle θ3A is 70° and the upper limit of the fourth angle θ4A is 20°; when the third angle θ3B is less than the fourth angle θ4B, the upper limit of the third angle θ3A is 20° and the upper limit of the fourth angle θ4A is 70°.

[0039] Furthermore, the first protrusions 30 and the second protrusions 40 are formed in multiple numbers on the design surface 2, and the flat surfaces 31 of at least some of the multiple first protrusions 30 are formed parallel to the plane forming the rib portion 22.

[0040] Furthermore, the groove portions 21 are formed in multiple numbers on the design surface 2, and at least some of the multiple groove portions 21 are through grooves extending from one end to the other end in the left-right direction D1 of the design surface 2, and the protrusions 30, 40 are formed in multiple numbers on the design surface 2, and at least some of the protrusions 30, 40 of the multiple pieces 30, 40 are formed at the ends of the through grooves.

[0041] A plurality of rib portions 22 are formed on the design surface 2, and V-shaped grooves 23A and 23B are formed on the surface of at least some of the plurality of rib portions 22.

[0042] The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present invention. (1) The building board of the above embodiment can be used not only as an exterior wall board but also as a building board for other purposes such as an interior wall material. (2) The building boards in the above embodiments are not limited to boards made of ceramic materials, but may be boards made of metal such as metal siding, concrete boards, wooden boards, or the like. (2) In the above embodiment, it is assumed that the building board of the present invention is laid horizontally, but this is not limiting and it may be laid vertically. (3) In the above embodiment, a stone pattern is applied to the flat surface 31 of the first protrusion 30. However, the pattern is not limited to a stone pattern and may be, for example, uneven. Furthermore, no pattern may be applied. (4) In the above embodiment, the upper limit of the angle θ6 between the left side θ5 and the right side of the virtual plane P and the first and second protrusions 30 and 40 is preferably 70°. [Explanation of symbols]

[0043] 1...Architectural board, 2...Design aspect, 3...Back side, 11...Top side, 12...lower side, 13...Right side, 14...left side, 21...groove portion, 21A...first curved surface (the upper end side of the groove portion 21 in the vertical direction D2), 21B...second curved surface (the lower end side of the groove portion 21 in the up-down direction D2), 21C... bottom surface (bottom surface of groove portion 21), 22...Rib portion, 22A...upper end portion of the rib portion 22 in the up-down direction D2, 22B: Lower end of the rib portion 22 in the up-down direction D2 23A...Groove 23A (Groove 23A is deeper than groove 23B) 23B…Groove 23B 30, 40...Protrusion (30: first protrusion, 40: second protrusion) 30A...first flat protrusion (a protrusion of the first protrusion 30 whose first surface 31 is located below the groove 21 in the up-down direction) 30B... second flat protrusion (a protrusion of the first protrusion 30 whose first surface 31 is located above the groove 21 in the up-down direction), 31...first plane (flat surface of the first protrusion 30), 32...second plane (an inclined surface inclined from one end of the flat surface of the first protrusion 30 in the up-down direction D2 toward the back surface 3), 31A...first A plane (flat surface of the first flat protrusion 30A), 32A... second A plane (an inclined surface inclined from one end of the flat surface of the first flat protrusion 30A in the up-down direction D2 toward the back surface 3), 31B...1B plane (flat surface of the second flat protrusion 30B), 32B... second B plane (an inclined surface inclined from one end of the flat surface of the second flat protrusion 30B in the up-down direction D2 toward the back surface 3), 40A...first inclined protrusion (the inclination of the first inclined surface 41 is steeper than the inclination of the second inclined surface 42), 40B... second inclined protrusion (the inclination of the first inclined surface 41 is gentler than the inclination of the second inclined surface 42), 41...Third plane (an inclined surface extending in a direction from the back side to the front side in the front-back direction D3 of the second protrusion), 42...Fourth plane (an inclined plane extending from the front end of the inclined plane 41 of the second protrusion toward the back side), 41A...3A plane (an inclined surface extending obliquely in a direction from the back surface side to the front surface side of the first inclined protrusion 40A in the front-back direction D3), 42A...4A plane (an inclined surface extending obliquely from the front-side end of the inclined surface 41A of the first inclined protrusion 40A toward the back-side), 41B...3B plane (an inclined surface extending obliquely in a direction from the back surface side to the front surface side in the front-back direction D3 of the first inclined protrusion 40B), 42B...4B plane (an inclined surface extending obliquely from the front-side end of the inclined surface 41B of the first inclined protrusion 40B toward the back-side), 50...Upper part 60...Lower part D1...Left and right direction, D2...Vertical direction, D3: Front and back direction, P...imaginary plane. θ1…first angle θ2…Second angle θ3...Third angle θ4…4th angle θ5…5th angle θ6…6th angle Direction, P...imaginary plane.

Claims

1. A building board having a rectangular shape in plan view and a design surface on its surface, A groove portion extending in a first direction along one side of the building board and having an inner surface at least partially formed by a curved surface; a rib portion located between the groove portions of the building board and extending in the first direction; a protrusion formed in the groove and extending in the first direction, the protrusion includes a first protrusion having a flat surface parallel to a surface of the rib portion extending in the second direction from one of one end side and the other end side of the groove portion in the second direction, and an inclined surface extending from the other end of the flat surface to an inner surface of the groove portion and in contact with the inner surface; a first inclined surface extending obliquely from one of the one end side and the other end side of the groove portion toward the surface side of the building board; a second protrusion having a second inclined surface extending obliquely from the other side of the groove toward the surface of the building board, Architectural board.

2. a plurality of the first protrusions and a plurality of the second protrusions are formed on the design surface; the first protrusions and the second protrusions are randomly arranged on the design surface. The building board according to claim 1.

3. The first protrusion and the second protrusion are formed in plurality on the design surface, a width of the flat surface of the first protrusion in the second direction is greater than a width of the inclined surface in the second direction; The flat surface of at least some of the first protrusions among the plurality of first protrusions has an uneven surface. The building board according to claim 1.

4. an imaginary plane that is in contact with the bottom of the groove and is parallel to the surface of the rib; a first angle formed with the flat surface is smaller than a second angle formed with the virtual plane and the inclined surface; a third angle formed between the virtual plane and the third plane and a fourth angle formed between the virtual plane and the fourth plane are different from each other. The building board according to claim 1.

5. When the third angle is greater than the fourth angle, the upper limit of the third angle is 70°; the upper limit of the fourth angle is 20°; When the third angle is smaller than the fourth angle, the upper limit of the third angle is 20°; The upper limit of the fourth angle is 70°. The building board according to claim 4.

6. a plurality of the first protrusions and a plurality of the second protrusions are formed on the design surface; The flat surface of at least some of the first protrusions among the plurality of first protrusions is formed parallel to a surface of the rib portion. The building board according to claim 1.

7. A plurality of the grooves are formed on the design surface, At least some of the grooves are through grooves extending from one end to the other end of the design surface in the first direction, A plurality of the protrusions are formed on the design surface, At least some of the plurality of protrusions are formed at the ends of the through grooves. The building board according to claim 1.

8. A plurality of the rib portions are formed on the design surface, At least some of the rib portions have grooves formed on the surface thereof. The building board according to claim 1.

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