Wooden shaft material, and joint structure of wooden shaft material
By employing medium density fiberboard to form a wooden shaft material with a core and reinforcement layers, the issues of poor yield and variability in conventional wooden shaft materials are addressed, resulting in a product with consistent appearance and strength.
Patent Information
- Application Number
- JP2023168769
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2023-09-28
- Publication Date
- 2025-04-09
AI Technical Summary
Conventional wooden shaft materials, such as sawn or laminated timber, suffer from poor yield due to significant waste, inability to utilize logs with defects, and variations in appearance and bending strength caused by wood grain and fiber direction.
The use of medium density fiberboard (MDF) to create a wooden shaft material with a core made of folded MDF and reinforcement layers also made of folded MDF, which can include spiral wound configurations and alternating right- and left-hand wound layers, to achieve uniform appearance and strength.
This approach results in a wooden shaft material with reduced weight, improved yield, consistent appearance, and uniform bending strength, allowing for efficient use of materials and flexible manufacturing to accommodate different lengths and strengths.
Smart Images
Figure 2025058680000001_ABST
Abstract
Description
[Technical field]
[0001] The present invention relates to a wooden shaft and a joint structure for a wooden shaft. [Background technology]
[0002] Traditionally, the shaft materials for pillars, beams, and other components of wooden buildings have been made from lumber cut from logs or processed laminated timber made by stacking pieces of wood with small cross-sectional dimensions (lamina) and bonding them together with adhesive (see, for example, Patent Document 1 below). [Prior art documents] [Patent documents]
[0003] [Patent Document 1] JP 2008-163651 A Summary of the Invention [Problem to be solved by the invention]
[0004] However, when sawn lumber or laminated lumber is used as the shaft material, the yield is low at about 60% because the surrounding scraps are discarded. In addition, logs with cracks, warping, knots, scratches, etc. cannot be used, which is a problem of not being able to make effective use of wood materials. Furthermore, sawn lumber and laminated lumber have problems such as variations in appearance due to the grain, and variations in bending strength due to the fiber direction.
[0005] The present invention has been made in consideration of the above-mentioned points, and its object is to provide a wooden shaft material and its joint structure which have small variations in appearance and bending strength and good yield. [Means for solving the problem]
[0006] In order to achieve the above object, in this invention, the wooden shaft is made of medium density fiberboard.
[0007] Specifically, the first invention is a wooden shaft material having a rectangular cross section, characterized in that it comprises a core material made of medium-density fiberboard bent into a rectangular tube, and at least one reinforcing material made of medium-density fiberboard bent into a rectangular tube that is arranged around the core material so as to surround the core material.
[0008] Here, the term "rectangle" includes a rectangle with rounded corners.
[0009] In the first invention, the wooden shaft is made of a core material made of medium density fiberboard bent into a rectangular tube shape and at least one reinforcing material made of medium density fiberboard surrounding the core material. In other words, the wooden shaft is made of medium density fiberboard. The raw material for medium density fiberboard can be wood with cracks, warping, knots, scratches, etc., or waste wood. In addition, unlike lumber or laminated lumber, medium density fiberboard does not have variation in appearance due to wood grain, and since it does not have a fiber direction, it is difficult for variation in bending strength to occur and the bending strength is almost uniform. Therefore, according to the first invention, it is possible to provide a wooden shaft with small variation in appearance and bending strength and good yield.
[0010] Incidentally, when constructing a wooden shaft from medium density fiberboard, it is also possible to form a columnar body, rather than a plate-shaped body, into the wooden shaft using a manufacturing method similar to that for medium density fiberboard.
[0011] However, it is difficult to press-mold the columnar body using the same manufacturing method as that for medium-density fiberboard, and the manufacturing process is time-consuming. In addition, wooden shafts made of columnar bodies formed using the same manufacturing method as that for medium-density fiberboard are heavy and difficult to install.
[0012] Therefore, in the first aspect of the present invention, the wooden shaft is configured to be hollow. With this configuration, it is possible to reduce the weight of the wooden shaft using medium density fiberboard.
[0013] The second invention is characterized in that, in the first invention, the reinforcing material is formed by folding and spirally winding a strip-shaped medium-density fiberboard around the outer peripheral surface of the core material or around the outer peripheral surface of the reinforcing material provided around the core material.
[0014] In the second aspect of the present invention, the reinforcing material is made by folding and spirally winding a strip of medium density fiberboard, so the length of the reinforcing material can be freely changed by simply changing the number of times the strip of medium density fiberboard is wrapped around it, making it easy to make wooden shafts of different lengths.
[0015] The third invention is characterized in that, in the second invention, the reinforcing material is provided in a plurality of pieces around the core material, at least one of the plurality of reinforcing materials is a right-handed wound material in which the strip-shaped medium-density fiberboard is wound in a right-handed thread direction, and the remaining reinforcing materials are left-handed wound materials in which the strip-shaped medium-density fiberboard is wound in a left-handed thread direction.
[0016] In the third invention, a plurality of reinforcing members are provided around a rectangular tubular core member, each of which is made by folding and spirally winding a strip of medium density fiberboard. This configuration makes it possible to provide a lightweight wooden shaft with high rigidity. In addition, by changing the number of reinforcing members provided around the core member, the thickness and strength of the wooden shaft can be easily changed.
[0017] A fourth invention is the third invention, characterized in that the right-handed winding material and the left-handed winding material are alternately provided around the core material.
[0018] In the fourth invention, right-handed and left-handed winding materials are alternately arranged around the core material. In this way, a plurality of strip-shaped medium density fiberboards are layered around the core material while alternating the winding direction between the right-handed and left-handed thread directions to form a multi-layer reinforcing material. With this configuration, even if stress is generated in the wooden shaft material, the reinforcing material is less likely to peel off, and the bending strength is also increased.
[0019] The fifth invention is a wooden shaft joining structure for joining two wooden shafts in the longitudinal direction, the two wooden shafts being wooden shafts according to any one of the first to fourth inventions, characterized in that a joining member having a rectangular cross section is provided within the core material at the joint between the two wooden shafts so as to span the two wooden shafts, and each of the joints between the two wooden shafts has a pinhole into which a connecting pin is inserted for connecting the joining member to the joint, and the two wooden shafts are joined by connecting the joining member provided within the core material at the joint between the two wooden shafts to each of the two wooden shafts with the connecting pin inserted into the pinhole.
[0020] In the fifth invention, the two wooden shafts to be joined are hollow, made of a core material and reinforcing material made of medium density fiberboard bent into a rectangular tube, a joining member with a rectangular cross section is provided in the hollow portion (inside the core material) of both wooden shafts, and the joining member is connected to the joint portion of both wooden shafts with a connecting pin. With this configuration, when joining two wooden shafts, it is possible to easily join the two wooden shafts in the length direction by simply inserting the joining member into the hollow portion and connecting the joining member to both wooden shafts with a connecting pin without forming insertion holes for the joining member in the two wooden shafts.
[0021] The sixth invention is a joint structure for joining first and second wooden shafts so that the end surface of the first wooden shaft abuts against the side surface of the second wooden shaft, the first and second wooden shafts being made of the wooden shafts according to any one of the first to fourth inventions, the second wooden shaft being formed at a portion where the end surface of the first wooden shaft abuts against the second wooden shaft with a joint hole having a rectangular cross section that extends the inner cavity of the core material of the first wooden shaft to the inner cavity of the core material of the second wooden shaft, and the joint portion of the first and second wooden shafts is formed with a joint hole having a rectangular cross section that extends the inner cavity of the core material of the first wooden shaft to the inner cavity of the core material of the second wooden shaft. A joining member having a rectangular cross section is provided so as to extend from within the core material through the joining hole into the core material of the second wooden shaft material, and a pin hole is formed in each of the joint portions of the first and second wooden shaft materials, into which a connecting pin is inserted for connecting the joining member to the joint portion, and the first and second wooden shaft materials are joined by connecting the joining member provided in the core material of the joint portion of the first and second wooden shaft materials to the first and second wooden shaft materials, respectively, with the connecting pin inserted into the pin hole.
[0022] In the sixth invention, the first and second wooden shafts to be joined are hollow, made of a core material and a reinforcing material made of a medium density fiberboard bent into a rectangular tube, a joint hole is formed in the second wooden shaft where the end surface of the first wooden shaft abuts, a joint member having a rectangular cross section is provided so as to extend from the hollow part (in the core material) of the first wooden shaft to the hollow part (in the core material) of the second wooden shaft through the joint hole, and the joint member is connected to the joint part of the first and second wooden shafts with a connecting pin. With this configuration, when joining two wooden shafts, the first and second wooden shafts can be easily joined vertically by simply forming a joint hole in the second wooden shaft, inserting the joint member so as to extend through the hollow parts (in the core material) of the first and second wooden shafts through the joint hole, and connecting the joint member to the first and second wooden shafts with a connecting pin. Effect of the Invention
[0023] As described above, according to the present invention, by constructing wooden shafts using medium density fiberboards, it is possible to provide wooden shafts and their joint structures that have little variation in appearance and bending strength and have a high yield. [Brief description of the drawings]
[0024] [Figure 1] FIG. 1 is a perspective view showing an upper portion of a wooden shaft according to the first embodiment. [Diagram 2] FIG. 2 is an exploded view showing the components of the wooden shaft of FIG. [Diagram 3] FIG. 3 is a perspective view showing the state of the core material before and after bending. [Figure 4] FIG. 4 is a plan view showing the state of the core material before and after bending. [Diagram 5] FIG. 5 is a diagram showing a procedure for forming a reinforcing material by winding a strip-shaped medium density fiberboard around a core material. [Figure 6] FIG. 6 is a perspective view showing a schematic configuration of a joint structure for joining two wooden shaft members that will become pillars in the longitudinal direction. [Figure 7] FIG. 7 is a perspective view showing a schematic configuration of a joint structure in which two wooden shaft members which will become pillars are joined to a wooden shaft member which will become a beam in a beam-to-beam manner. [Figure 8] FIG. 8 is a perspective view showing a schematic configuration of a joint structure for joining a wooden shaft member that will become a beam to a wooden shaft member that will become a column. [Figure 9] FIG. 9 is a perspective view showing a schematic configuration of a joint structure in which two wooden shaft members that will become beams are joined to a wooden shaft member that will become a pillar in a column-to-column manner. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0025] Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings. The following embodiments are essentially preferred examples, and are not intended to limit the scope of the present invention, its applications, or its uses.
[0026] First Embodiment of the Invention 1 and 2, wooden shaft 10 includes a core material 1 made of a medium-density fiberboard A bent into a rectangular tube shape, and at least one (three in this embodiment 1) reinforcing material 2 made of a medium-density fiberboard B bent into a rectangular tube shape and disposed around core material 1 so as to surround core material 1. Wooden shaft 10 is configured into a rectangular tubular body having a hollow portion with a rectangular cross section by the rectangular tubular core material 1 and the at least one rectangular tubular reinforcing material 2.
[0027] Here, the term "rectangle" includes a rectangle with rounded corners. In the first embodiment, as shown in Fig. 1, the core material 1 and the three reinforcing materials 2, 2, 2 are all formed to have a cross section in the shape of a rectangle with rounded corners.
[0028] The wooden shaft 10 is configured so that the outer dimensions are 45 mm to 1000 mm in both length and width, and the inner dimensions (dimensions of the hollow portion) are 10 mm to 600 mm in both length and width. The length of the wooden shaft 10 can be freely changed, and the wooden shaft 10 can also be used in place of a laminated lumber piece having a length of about 12000 mm.
[0029] [Core material] Core 1 has a density of 0.7 g / cm 3 More than 0.85g / cm 3 The board is made of medium density fiberboard (MDF) having a thickness of 1.5 mm to 3.0 mm. In this embodiment, the board has a density of 0.79 g / cm 3 The core material 1 is made of medium density fiberboard A having a thickness of 2.0 mm.
[0030] 3 and 4, the medium-density fiberboard A constituting the core material 1 is formed in a rectangular shape. One surface of the medium-density fiberboard A (the surface that becomes the inner surface after bending and forming, hereinafter referred to as the inner surface) is formed with a groove portion 3 consisting of at least one groove (five in this embodiment) extending from one end to the other end in the length direction. The groove portion 3 is provided to make it easier to bend the medium-density fiberboard A when bending the medium-density fiberboard A to form the rectangular tubular core material 1.
[0031] The grooves 3 are formed in four locations on the inner surface of the medium-density fiberboard A. In this embodiment 1, the four grooves 3 are arranged at equal intervals on the inner surface of the medium-density fiberboard A at a pitch of one-fourth the width of the medium-density fiberboard A to form a core material 1 with a square cross-sectional shape. In this embodiment 1, the grooves 3 are composed of five grooves that are equally spaced and have the same dimensions. Each groove has a rectangular cross-sectional shape, and is formed so that the distance between the groove bottom and the outer surface (the back surface of the inner surface) of the medium-density fiberboard A is 0.5 mm to 1.0 mm.
[0032] The groove portion 3 is not limited to the above configuration, and may be any configuration that allows the medium density fiberboard A to be folded into a rectangular tube (including a rectangular cross section with rounded corners). For example, the number of grooves constituting the groove portion 3 may be 1 to 4 or 6 or more, and the cross-sectional shape of the grooves constituting the groove portion 3 is not limited to a rectangular shape, and may be a V-shape or a U-shape.
[0033] The core material 1 is formed into a rectangular tube shape (a tube shape with a square cross section in the present embodiment 1) by bending the medium density fiberboard A at right angles at each groove 3. The medium density fiberboard A bent into a rectangular tube shape has a plurality of staples 4, ..., 4 driven in so as to straddle both ends in the width direction so as to maintain the shape after molding. In the present embodiment 1, as shown in FIG. 4, both end faces (end grain faces) in the width direction of the medium density fiberboard A are flat surfaces, and the both end faces in the width direction are butted together, and the staples 4, ..., 4 are driven in so as to straddle both ends in the width direction, thereby fixing both ends in the width direction. Note that the structure for fixing both ends in the width direction of the medium density fiberboard A is not limited to the above. For example, both ends in the width direction of the medium density fiberboard A may be subjected to joint processing such as joint processing or joint processing, and then the both ends in the width direction of the medium density fiberboard A may be joined, and then fixed with an adhesive or the above staples 4, ..., 4.
[0034] [Reinforcement material] Reinforcement 2 has a density of 0.7 g / cm 3 More than 0.85g / cm 3The board is made of medium density fiberboard (MDF) having a thickness of 1.5 mm to 3.0 mm. In this embodiment, the board has a density of 0.79 g / cm 3 Reinforcement material 2 is made of medium density fiberboard B having a thickness of 2.0 mm.
[0035] In the present embodiment 1, the wooden shaft 10 includes three reinforcing materials 2. The three reinforcing materials 2, 2, 2 are composed of a first reinforcing material 2a in which a strip-shaped medium-density fiberboard B is wrapped around the core material 1, a second reinforcing material 2b in which a strip-shaped medium-density fiberboard B is wrapped around the first reinforcing material 2a, and a third reinforcing material 2c in which a strip-shaped medium-density fiberboard B is wrapped around the second reinforcing material 2b.
[0036] 2 and 5, the medium-density fiberboard B constituting the reinforcing material 2 is formed in a strip shape (long, narrow rectangular shape). One surface of the medium-density fiberboard B (the surface that becomes the inner surface after bending and forming, hereinafter referred to as the inner surface) is formed with a groove portion 5 consisting of at least one groove (five in this embodiment) that extends at an angle with respect to the width direction from one end to the other end in the width direction. The groove portion 5 is provided to make it easier to bend the medium-density fiberboard B when the strip-shaped medium-density fiberboard B is folded and spirally wound around the outer peripheral surface of the object to be wound to form the rectangular tubular reinforcing material 2.
[0037] The grooves 5 are formed at a plurality of locations on the inner surface of the medium density fiberboard B. In this embodiment 1, in order to form a reinforcing material 2 having a square cross section, the plurality of grooves 5 are arranged parallel to each other at equal intervals on the inner surface of the medium density fiberboard B. The plurality of grooves 5 are arranged at a pitch corresponding to the length of the four sides of the object to be wound (core material 1, first reinforcing material 2a or second reinforcing material 2b) having a rectangular cross section. Specifically, the plurality of grooves 5 are arranged at a pitch corresponding to the length of the four sides of the core material 1 in the first reinforcing material 2a, at a pitch corresponding to the length of the four sides of the first reinforcing material 2a in the second reinforcing material 2b, and at a pitch corresponding to the length of the four sides of the second reinforcing material 2b in the third reinforcing material 2c.
[0038] In the present embodiment 1, the groove portion 5 is composed of five grooves that are equally spaced and have the same dimensions. Each groove has a rectangular cross-sectional shape, and is formed so that the distance between the groove bottom and the outer surface (the back surface of the inner surface) of the medium density fiberboard B is 0.5 mm to 1.0 mm.
[0039] The reinforcing material 2 is formed into a rectangular tube (a tube with a square cross section in the present embodiment 1) by spirally winding the strip-shaped medium-density fiberboard B around the object to be wound (core material 1, first reinforcing material 2a, second reinforcing material 2b) while bending the strip-shaped medium-density fiberboard B at right angles at each groove 5. The strip-shaped medium-density fiberboard B is wound around the outer peripheral surface of the object to be wound without gaps and without overlapping vertically. The inclination angle of the groove 5 is appropriately set so that the strip-shaped medium-density fiberboard B can be wound around the object to be wound without gaps and without overlapping vertically. The strip-shaped medium-density fiberboard B is bonded to the outer peripheral surface of the object to be wound with an adhesive. Urea resin, urea-melamine resin, melamine resin, phenol resin, isocyanate resin, resorcinol resin, vinyl acetate resin, aqueous vinyl urethane resin, etc. can be used as the adhesive.
[0040] In the present embodiment 1, of the three reinforcing materials 2, 2, 2, the second reinforcing material 2b is a right-handed wound material in which a strip-shaped medium-density fiberboard B is wound in a right-handed screw direction, and the remaining first and third reinforcing materials 2a and 2c are left-handed wound materials in which a strip-shaped medium-density fiberboard B is wound in a left-handed screw direction. In other words, in the present embodiment 1, right-handed and left-handed wound materials are alternately provided around the core material 1.
[0041] [Medium density fiberboard] The medium density fiberboard A constituting the core material 1 and the medium density fiberboard B constituting the reinforcing material 2 are constructed in the same manner, although they have different dimensions. The medium density fiberboards A and B contain an adhesive with excellent water resistance. In this embodiment 1, the medium density fiberboards A and B contain a urea-melamine co-condensation resin adhesive. The adhesive used for the medium density fiberboards A and B is not limited to the urea-melamine co-condensation resin adhesive, and may contain diphenylmethane diisocyanate, phenolic resin, etc. In addition, in this embodiment 1, the medium density fiberboards A and B are added with paraffin (water repellent) in an amount necessary for the surface to be water repellent (the contact angle of water at any point on the surface is greater than 90 degrees). In other words, the medium density fiberboards A and B are constructed so that the surface is water repellent.
[0042] -Manufacturing method for wooden shafts- The wooden shaft 10 is manufactured as follows.
[0043] 2 and 3, a medium density fiberboard A is folded at the groove 3 to form a rectangular tube. Then, staples 4, ..., 4 are driven in to maintain the shape (rectangular tube) after folding.
[0044] After the core material 1 is formed, as shown in Figure 5, a strip-shaped medium-density fiberboard B is folded at the groove portion 5 and spirally wrapped around the outer peripheral surface of the core material 1 in a left-handed screw direction and adhered to the core material 1, thereby forming a rectangular tubular first reinforcing material 2a around the core material 1.
[0045] After the first reinforcing material 2a is formed, a strip-shaped medium-density fiberboard B is folded at the groove portion 5 and spirally wrapped in a right-handed screw direction around the outer peripheral surface of the first reinforcing material 2a and adhered to the board, thereby forming a rectangular tubular second reinforcing material 2b around the first reinforcing material 2a.
[0046] After the second reinforcing material 2b is formed, a strip-shaped medium-density fiberboard B is folded at the groove portion 5 and spirally wrapped in a left-handed screw direction around the outer peripheral surface of the second reinforcing material 2b and adhered to the outer peripheral surface, thereby forming a rectangular tubular third reinforcing material 2c around the second reinforcing material 2b.
[0047] After the third reinforcing member 3c is formed, a pressing member such as a rubber band is wrapped around the band-shaped medium density fiberboard B so as not to loosen until the adhesive hardens.
[0048] After the adhesive has hardened, the pressing member such as the rubber band is removed. If it takes time for the adhesive to harden, a drying machine such as a hairdryer may be used.
[0049] Through the above steps, the wooden shaft 10 is manufactured.
[0050] -Wooden shaft joint structure- Next, the joint structures S1 to S4 of the wooden shaft 10 will be described with reference to Figures 6 to 9. Although Figures 6 to 9 only show the outer shape of the wooden shaft 10, each wooden shaft 10 includes a core material 1 and at least one reinforcing material 2, as described above. Furthermore, for convenience of illustration in Figures 6 to 9, the wooden shaft 10 is depicted as having a rectangular tube shape with sharp corners, but as described above, in the first embodiment, the core material 1 and the three reinforcing materials 2, 2, 2 are all formed to have a rectangular cross section with rounded corners, and therefore the wooden shaft 10 is also actually formed to have a rectangular cross section with rounded corners.
[0051] [Joint structure S1] As shown in FIG. 6, the joint structure S1 is for joining two wooden shaft members 10, 10 in the longitudinal direction (vertical joint), and is applicable, for example, when two wooden shaft members 10, 10 are joined to be used as a pillar.
[0052] In the joint structure S1, two wooden shafts 10, 10 are joined in the longitudinal direction using one joint member 20 and two connecting pins 21, 21.
[0053] The joint member 20 is a highly rigid rod-shaped member with a rectangular cross section that can be inserted into the hollow portion (inside the core material 1) of the two wooden shafts 10, 10, and is made of a steel pipe in this embodiment. The joint member 20 has pin holes into which the connecting pins 21, 21 are inserted. The joint member 20 is inserted into the hollow portion (inside the core material 1) of the joint portion of the two wooden shafts 10, 10 so as to straddle both wooden shafts 10, 10. Note that a steel pipe with outer dimensions of 10 mm to 600 mm in both length and width, 40 mm to 12,000 mm in length, and 1 mm to 22 mm in thickness can be used as the joint member 20, but in order to suppress rattling in the hollow portion of the wooden shafts 10, 10, it is preferable to use a steel pipe with outer dimensions slightly smaller than the inner dimensions of the wooden shafts 10, 10.
[0054] At the joint portion of the two wooden shafts 10, 10, into which the joint member 20 is inserted, pin holes are formed, into which connecting pins 21, 21 for connecting the joint member 20 to the joint portion are inserted.
[0055] The connecting pins 21, 21 are drift pins, and after the connecting member 20 is inserted into the hollow portions (inside the core material 1) of the two wooden shaft materials 10, 10, they are inserted into the joint portions of each wooden shaft material 10 and the pin holes of the connecting member 20, and are then tightened using a lock nut or the like to connect the joint portions of each wooden shaft material 10 to the connecting member 20.
[0056] In this way, in the joint structure S1, two wooden shaft materials 10, 10 are lined up in the longitudinal direction, and a joint member 20 with a rectangular cross section is inserted into the hollow portion (inside the core material 1) of both wooden shaft materials 10, 10.The joint member 20 is then connected to the joint portion of both wooden shaft materials 10, 10 with connecting pins 21, 21, thereby joining the two wooden shaft materials 10, 10 in the longitudinal direction (vertical joint).
[0057] [Joint structure S2] As shown in Figure 7, the joint structure S2 joins two vertically extending wooden shafts (first wooden shafts) 10A, 10A to one horizontally extending wooden shaft (second wooden shaft) 10B, and is applicable, for example, to a case where two first wooden shafts 10A, 10A that serve as pillars are joined to one second wooden shaft 10B that serves as a beam in a beam-to-beam (horizontal) manner.
[0058] In the joint structure S2, one joint member 20 and three connecting pins 21, 21, 21 are used to join two first wooden shafts 10A, 10A extending vertically to one second wooden shaft 10B extending horizontally.
[0059] The first wooden shaft 10A is made of the wooden shaft 10 with a square cross section. On the other hand, the second wooden shaft 10B is made of the wooden shaft 10 with a rectangular cross section. The wooden shaft 10 with a rectangular cross section can be formed by appropriately changing the intervals of the grooves 3, 5 formed on the inner surface of the medium density fiberboards A, B. At the part of the second wooden shaft 10B where the buttock faces of the first wooden shafts 10A, 10A abut, a joint hole with a rectangular cross section is formed that extends the hollow part (in the core material 1) of the first wooden shafts 10A, 10A to the hollow part (in the core material 1) of the second wooden shaft 10B. The joint hole is formed to insert the joint member 20 from the hollow part (in the core material 1) of the first wooden shafts 10A, 10A to the hollow part (in the core material 1) of the second wooden shaft 10B.
[0060] The joint member 20 is a highly rigid rod-shaped member with a rectangular cross section (square in FIG. 7) that can be inserted into the hollow portion (in the core material 1) of the two first wooden shafts 10A and the hollow portion (in the core material 1) of the single second wooden shaft 10B, and is made of a steel pipe in this embodiment. The joint member 20 has pin holes into which the connecting pins 21 are inserted. The joint member 20 is inserted into the hollow portion (in the core material 1) of the joint portion of the two first wooden shafts 10A and the hollow portion (in the core material 1) of the single second wooden shaft 10B so as to straddle the three wooden shafts 10A, 10B, and 10A.
[0061] At the joint portion of the two first wooden shafts 10A, 10A where the joint members 20 are inserted, pin holes are formed for inserting connecting pins 21, 21 for connecting the joint members 20 to the joint portion. At the joint portion of the second wooden shaft 10B where the joint members 20 are inserted, pin holes are formed for inserting connecting pins 21 for connecting the joint members 20 to the joint portion.
[0062] The connecting pins 21, 21, 21 are drift pins, and after the connecting member 20 is inserted into the hollow portions (inside the core material 1) of the three wooden shaft materials 10A, 10B, 10A, they are inserted into the joint portions of each wooden shaft material 10 and the pin holes of the connecting member 20, and are then tightened using a lock nut or the like to connect the joint portions of each wooden shaft material 10 to the connecting member 20.
[0063] In this way, in the joining structure S2, a joining hole is formed in the portion of the second wooden axis material 10B where the end faces of the first wooden axis materials 10A, 10A abut, and a joining member 20 with a rectangular cross section is provided so as to span the hollow portions (inside the core material 1) of the three wooden axis materials 10A, 10B, 10A, and the joining member 20 is connected to the joining portions of the three wooden axis materials 10A, 10B, 10A with connecting pins 21, 21, 21, thereby joining the two vertically extending wooden axis materials (first wooden axis materials) 10A, 10A laterally to one horizontally extending wooden axis material (second wooden axis material) 10B.
[0064] [Joint structure S3] As shown in FIG. 8, the joint structure S3 joins a single horizontally extending wooden axis (first wooden axis) 10A to a single vertically extending wooden axis (second wooden axis) 10B, and is applicable, for example, to a case where a single first wooden axis 10A serving as a beam is joined to a single second wooden axis 10B serving as a pillar in a column-to-column (vertical) manner.
[0065] In the joint structure S3, a first wooden shaft 10A extending in the horizontal direction is joined to a second wooden shaft 10B extending in the vertical direction using one joint member 20 and two connecting pins 21, 21.
[0066] The second wooden shaft 10B is made of the wooden shaft 10 with a square cross section. On the other hand, the first wooden shaft 10A is made of the wooden shaft 10 with a rectangular cross section. The wooden shaft 10 with a rectangular cross section can be formed by appropriately changing the intervals of the grooves 3, 5 formed on the inner surface of the medium density fiberboards A, B. At the part where the end surface of the first wooden shaft 10 of the second wooden shaft 10B abuts, a joint hole with a rectangular cross section is formed that extends the hollow part (in the core material 1) of the first wooden shaft 10A to the hollow part (in the core material 1) of the second wooden shaft 10B. The joint hole is formed to insert the joint member 20 from the hollow part (in the core material 1) of the first wooden shaft 10A to the hollow part (in the core material 1) of the second wooden shaft 10B.
[0067] The joint member 20 is a highly rigid rod-shaped member with a rectangular cross section (rectangular in FIG. 8) that can be inserted into the hollow portion (in the core material 1) of the first wooden shaft 10A and the hollow portion (in the core material 1) of the second wooden shaft 10B, and in this embodiment, is made of a steel pipe. The joint member 20 has pin holes into which the connecting pins 21, 21 are inserted. The joint member 20 is inserted into the hollow portions (in the core material 1) of the first wooden shaft 10A and the second wooden shaft 10B so as to extend from the hollow portion (in the core material 1) of the joint portion of the first wooden shaft 10A through the joint hole to the hollow portion (in the core material 1) of the second wooden shaft 10B.
[0068] A pin hole is formed in the joint portion of the first wooden shaft 10A, into which the joint member 20 is inserted, into which a connecting pin 21 is inserted for connecting the joint member 20 to the joint portion. A pin hole is also formed in the joint portion of the second wooden shaft 10B, into which the joint member 20 is inserted, into which a connecting pin 21 is inserted for connecting the joint member 20 to the joint portion.
[0069] The connecting pins 21, 21 are drift pins, and after the connecting member 20 is inserted into the hollow portions (inside the core material 1) of the two wooden shaft materials 10A, 10B, they are inserted into the joint portions of each wooden shaft material 10 and the pin holes of the connecting member 20, and are then tightened using a lock nut or the like to connect the joint portions of each wooden shaft material 10 to the connecting member 20.
[0070] In this way, in the joining structure S3, a joining hole is formed in the portion where the end surface of the first wooden shaft material 10A of the second wooden shaft material 10B abuts, and a joining member 20 with a rectangular cross section is provided so as to extend from the hollow portion of the first wooden shaft material 10A (inside the core material 1) to the hollow portion of the second wooden shaft material 10B (inside the core material 1) through the joining hole, and the joining member 20 is connected to the joining portions of the first and second wooden shaft materials 10A, 10B with connecting pins 21, 21, thereby vertically joining the wooden shaft material (first wooden shaft material) 10A extending in the horizontal direction to the wooden shaft material (second wooden shaft material) 10B extending in the vertical direction.
[0071] [Joint structure S4] As shown in Fig. 9, the joint structure S4 is a partial modification of the joint structure S3. Specifically, a beam is formed of two first wooden shafts 10A, 10A extending in the horizontal direction. In the joint structure S4, the first wooden shaft 10A is formed so that its vertical length (beam length) is shorter than that of the first wooden shaft 10A of the joint structure S4. The structure for joining each first wooden shaft 10A to the second wooden shaft 10B is the same as that of the joint structure S3, and therefore a detailed description thereof will be omitted.
[0072] -Effects of embodiment 1- In the first embodiment, the wooden shaft 10 is composed of a core material 1 made of a medium-density fiberboard A bent into a rectangular tube shape and at least one reinforcing material 2 made of a medium-density fiberboard B surrounding the core material 1. In other words, the wooden shaft 10 is composed of medium-density fiberboards A and B. The medium-density fiberboards A and B can be made from wood with cracks, warping, knots, scratches, etc., or waste wood. In addition, unlike lumber or laminated lumber, the medium-density fiberboards A and B do not have variations in appearance due to wood grain, and since they do not have a fiber direction, they are unlikely to have variations in bending strength and the bending strength is almost uniform. Therefore, according to the first embodiment, it is possible to provide a wooden shaft 10 with small variations in appearance and bending strength and good yield.
[0073] Incidentally, when constructing the wooden shaft 10 from medium density fiberboards A and B, it is also possible to form the wooden shaft 10 into a columnar body rather than a plate-shaped body using a manufacturing method similar to that for the medium density fiberboards A and B.
[0074] However, it is difficult and time-consuming to press-mold the columnar body using the same manufacturing method as the medium-density fiberboards A and B. In addition, the wooden shaft material 10 made of the columnar body formed using the same manufacturing method as the medium-density fiberboards A and B is heavy and difficult to install.
[0075] Therefore, in the present embodiment 1, the wooden shaft 10 is configured to be hollow. With such a configuration, the wooden shaft 10 using the medium density fiberboards A and B can be made lighter.
[0076] In addition, in the first embodiment, the reinforcing material 2 is formed by folding and spirally winding the strip-shaped medium-density fiberboard B, so the length of the reinforcing material 2 can be freely changed by simply changing the number of times the strip-shaped medium-density fiberboard B is wound. This makes it easy to form wooden shafts 10 of different lengths.
[0077] In the first embodiment, a plurality of (three) reinforcing members 2 are provided around the rectangular tubular core material 1, each of which is made by folding and spirally winding a strip-shaped medium-density fiberboard B. This configuration makes it possible to provide a lightweight, highly rigid wooden shaft material 10. Also, by changing the number of reinforcing members 2 provided around the core material 1, the thickness and strength of the wooden shaft material 10 can be easily changed.
[0078] In the first embodiment, at least one of the reinforcing materials 2 is made of a right-handed material wound with a strip-shaped medium-density fiberboard B in a right-handed screw direction, and the remaining reinforcing materials 2 are made of left-handed material wound with a strip-shaped medium-density fiberboard B in a left-handed screw direction, and the right-handed and left-handed materials are alternately provided around the core material 1. In this way, the multiple strip-shaped medium-density fiberboards B are layered around the core material 1 while alternating the winding direction between the right-handed screw direction and the left-handed screw direction to form multiple layers of reinforcing materials 2, ..., 2. With this configuration, even if stress is generated in the wooden shaft material 10, the reinforcing materials 2 are less likely to peel off, and the bending strength is also increased.
[0079] In the joint structure S1 of the first embodiment, the two wooden shafts 10, 10 to be joined are hollow, made of a core material 1 and a reinforcing material 2 made of medium density fiberboards A, B bent into a rectangular tube shape, and a joint member 20 with a rectangular cross section is provided in the hollow portion (inside the core material 1) of both wooden shafts 10, 10, and the joint member 20 is connected to the joint portion of both wooden shafts 10, 10 with connecting pins 21, 21. With this configuration, when joining the two wooden shafts 10, 10, it is possible to easily join the two wooden shafts 10, 10 in the longitudinal direction by simply inserting the joint member 20 into the hollow portion and connecting the joint member 20 to both wooden shafts 10, 10 with connecting pins 21, 21 without forming an insertion hole for the joint member 20 in the two wooden shafts 10, 10.
[0080] In addition, in the joining structures S2 to S4 of this embodiment 1, the first and second wooden shafts 10A, 10B to be joined are formed with a hollow core material 1 and reinforcing material 2 made of medium-density fiberboards A and B bent into a rectangular tube shape, and a joining hole is formed in the portion of the second wooden shaft 10B where the end surface of the first wooden shaft 10A abuts. A joining member 20 with a rectangular cross-section is provided to extend from the hollow portion of the first wooden shaft 10A (inside the core material 1) to the hollow portion of the second wooden shaft 10B (inside the core material 1) through the joining hole, and the joining member 20 is connected to the joining portion of the first and second wooden shafts 10A, 10B with connecting pins 21, 21. With this configuration, when joining two wooden shaft materials 10, 10, the first and second wooden shaft materials 10A, 10B can be easily joined vertically by simply forming a joining hole in the second wooden shaft material 10B, inserting the joining member 20 through the joining hole so that it spans the hollow portions (inside the core material 1) of the first and second wooden shaft materials 10A, 10B, and connecting the joining member 20 to the first and second wooden shaft materials 10A, 10B with connecting pins 21, 21.
[0081] Other Embodiments In the above-mentioned embodiment 1, the core material 1 and the three reinforcing materials 2, 2, 2 are all formed so that their cross sections are rectangular with rounded corners, and the wooden shaft material 10 is also formed so that its cross section is rectangular with rounded corners. However, the core material 1 and the reinforcing materials 2 may be formed so that their cross sections are rectangular with sharp corners. For example, by configuring the groove portion 3 of the core material 1 and the groove portion 5 of the reinforcing materials 2 each with a single V-shaped cross section, the core material 1 and the reinforcing materials 2 can be formed so that their cross sections are rectangular with sharp corners.
[0082] Furthermore, in the above-mentioned first embodiment, the wooden shaft 10 includes the core material 1 and the three reinforcing materials 2, 2, 2, but the wooden shaft 10 only needs to include at least one reinforcing material 2, and may include one, two, or four or more reinforcing materials 2. Even if the same core material 1 is used, the thickness and strength of the wooden shaft 10 can be easily changed by changing the number of reinforcing materials 2 provided around the core material 1.
[0083] In the above-mentioned first embodiment, the core material 1 and the reinforcing material 2 are each formed by bending one medium-density fiberboard A, B, but the core material 1 and the reinforcing material 2 may each be formed by bending a plurality of medium-density fiberboards A, B. For example, when the wooden shaft 10 is used instead of a long laminated lumber having a length of about 12000 mm, a plurality of medium-density fiberboards A are folded into a rectangular tube shape and connected in the length direction to form the core material 1, and a plurality of strip-shaped medium-density fiberboards B are wound around this long core material 1 from one end side to the other end side in the longitudinal direction while joining them together to form the long wooden shaft 10. [Industrial Applicability]
[0084] The present invention is useful for wooden shafts and joint structures of wooden shafts. [Explanation of symbols]
[0085] 1 Core material 2 Reinforcement 2a First reinforcement (reinforcement) 2b Second reinforcement (reinforcement) 2c Third reinforcement (reinforcement) 10 Wooden shaft 10A First Wooden Axis 10B Second wooden shaft 20 Joining materials 21 Connecting pin S1 joint structure S2 joint structure S3 joint structure S4 joint structure
Claims
1. A wooden shaft having a rectangular cross section, A core material made of a medium density fiberboard bent into a rectangular tube shape; and at least one reinforcing member made of a medium density fiberboard folded into a rectangular tube and disposed around the core material so as to surround the core material. A wooden shaft material characterized by:
2. The wooden shaft material according to claim 1, The reinforcing material is formed by folding and spirally winding a strip-shaped medium density fiberboard around the outer periphery of the core material or the outer periphery of the reinforcing material provided around the core material. A wooden shaft material characterized by:
3. The wooden shaft material according to claim 2, The reinforcing material is provided in plurality around the core material, At least one of the plurality of reinforcing materials is a right-handed wound material in which the strip-shaped medium-density fiberboard is wound in a right-handed screw direction, and the remaining reinforcing materials are left-handed wound materials in which the strip-shaped medium-density fiberboard is wound in a left-handed screw direction. A wooden shaft material characterized by:
4. The wooden shaft material according to claim 3, The right-handed and left-handed materials are alternately provided around the core material. A wooden shaft material characterized by:
5. A joint structure for joining two wooden shafts in the longitudinal direction, The two wooden shafts are the wooden shafts according to any one of claims 1 to 4, A joint member having a rectangular cross section is provided in the core material at the joint portion of the two wooden shafts so as to straddle the two wooden shafts, At the joint portions of the two wooden shafts, pin holes are formed, into which connecting pins for connecting the connecting members are inserted, The two wooden shafts are joined by connecting the joint members provided in the core material at the joint portions of the two wooden shafts to the two wooden shafts with the connecting pins inserted into the pin holes. A joint structure for wooden shaft members.
6. A joint structure for joining a first wooden shaft and a second wooden shaft such that a butt surface of the first wooden shaft abuts against a side surface of the second wooden shaft, The first and second wooden shaft members are made of the wooden shaft members according to any one of claims 1 to 4, A hole having a rectangular cross section is formed in the portion of the second wooden shaft where the end surface of the first wooden shaft abuts, the hole extending from the inner cavity of the core material of the first wooden shaft to the inner cavity of the core material of the second wooden shaft; A joint member having a rectangular cross section is provided at the joint portion between the first and second wooden shafts so as to extend from within the core material of the first wooden shaft through the hole to within the core material of the second wooden shaft; At the joint portions of the first and second wooden shafts, pin holes are formed, into which connecting pins for connecting the connecting members to the joint portions are inserted, The first and second wooden shafts are joined by connecting the joint members provided in the core material of the joint portion of the first and second wooden shafts to the first and second wooden shafts, respectively, with the connecting pins inserted into the pin holes. A joint structure for wooden shaft members.
Citation Information
Patent Citations
Joining and firm-fastening structure of wooden building, and fitting therefor
JP2008163651A