Joining metal fitting

Abstract

To provide a joint metal capable of easily joining structural members to each other.SOLUTION: The joint metal fitting 1 has a metal fitting body 10 for joining one member 21 and the other member 22 to be oppositely joined. The hardware body 10 has a hollow cylindrical shape opened from one end to the other end, and at least one groove 11 is formed from one end 4 to the other end 5 in the circumferential direction. The groove 11 is formed so as to be inclined to a virtual axis 3 of the hardware body 10, and has a bent part 12 bent by changing an inclination angle, a first part 13 extending to the bent part 12 from one end part, and a second part 14 bent in the inverse direction in the bent part 12 and extending to the other end part. In this way, when the joint metal fitting 1 is screwed into the one member 21 and the other member 22 from both ends, a force acts to reversely rotate the upper end side from the bent portion 12 and the lower end side from the bent portion 12, so that the rotation stops near the bent portion 12, and the structural members can be easily joined to each other.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a metal joint used to join structural members such as wood to wood, wood to concrete, or concrete to concrete in structures such as buildings. [Background technology]

[0002] In wooden structures, metal joints are sometimes used to join wooden pieces such as foundations, columns, cross members, etc. Patent Document 1 shows an example of a conventional metal joint.

[0003] FIG. 10 is a diagram showing the state of use of the conventional metal joint shown in Patent Document 1.

[0004] 10, a metal joint (wood screw) 100 includes a shaft 101 having a thread 103 formed thereon, and a conical head 102 formed at one end of the shaft. The metal joint (wood screw) 100 is screwed into wooden pieces 104, penetrating one piece of wooden piece 104a and screwing partway into the other piece of wooden piece 104b, thereby joining the pieces of wooden piece together.

[0005] However, in the metal joint shown in Patent Document 1, the head is exposed on the surface of the wood, which impairs the aesthetic appearance of the joint.

[0006] To address this issue, a metal joint as shown in Patent Document 2 has been proposed.

[0007] FIG. 11 is a diagram showing the state of use of the conventional metal joint disclosed in Patent Document 2.

[0008] Referring to Figure 11, the connecting hardware (connector) 110 is composed of a lag screw 112 screwed into one piece of wood 111a, an embedding tool 113 embedded in the other piece of wood 111b, and a stud bolt 114 inserted into the lag screw 112 and the embedding tool 113.

[0009] The lag screw 112 is a metal cylinder with a spirally extending ridge formed on its circumferential side surface. One end surface of the lag screw 112 is formed with a center hole into which a stud bolt 114 can be inserted. An internal female screw thread is formed below the center hole into which the stud bolt 114 is screwed.

[0010] The embedding tool 113 is a metal cylinder with ribs formed on its side surface that extend in the circumferential and axial directions. One end surface of the embedding tool 113 is formed with a center hole into which the stud bolt 114 can be inserted. An internal female screw thread is formed below the center hole into which the stud bolt 114 is screwed.

[0011] The stud bolt 114 is a round bar with male threads formed on both ends.

[0012] When joining two pieces of wood using this conventional joining hardware 110, a pair of pilot holes 115 extending from the contact surfaces of the pieces of wood to be joined are first drilled in the pieces of wood to be joined. Next, a lag screw 112 is screwed into the pilot hole 115a of one piece of wood 111a to be joined, and then a stud bolt 114 is inserted into the center hole of the lag screw 112, and one end of the stud bolt 114 is screwed into the internal threads of the lag screw 112. Next, the other end of the stud bolt 114 is inserted into the center hole of an embedding tool 113 and screwed into the internal threads of the embedding tool 113. Finally, adhesive 116 is applied to the periphery of the embedding tool 113, and the embedding tool 113 is embedded in the pilot hole 115b of the other piece of wood 111b to be joined. The pieces of wood 111a and 111b are brought into close contact with each other, and the adhesive 116 solidifies, joining the pieces of wood. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-295818 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-77545 Summary of the Invention [Problem to be solved by the invention]

[0014] However, the conventional metal joints described in Patent Document 2 above required a large number of parts and required the separate use of adhesive to solidify, making installation complicated.

[0015] An object of the present invention is to provide a metal joint that can easily join structural members such as wood to wood, wood to concrete, or concrete to concrete. [Means for solving the problem]

[0016] The premise of the present invention for solving the above-mentioned problems is a metal joint having a metal body for joining one material and a counterpart material that are joined opposite to each other.

[0017] The characteristics of the joining hardware of the present invention based on the above premise are that the hardware body has a hollow cylindrical shape that is open from one end to the other end, and at least one groove is formed in the circumferential direction from one end to the other end, and the groove is formed so as to be inclined with respect to the imaginary axis of the hardware body, and is provided with a bending portion that bends by changing the inclination angle, a first portion that extends from one end to the bending portion, and a second portion that bends in the opposite direction at the bending portion and extends to the other end.

[0018] In one example of the metal joint of the present invention, when the direction perpendicular to the axial direction of the metal body is defined as the horizontal direction, the first and second parts extend symmetrically with respect to an imaginary horizontal plane passing through the bent portion.

[0019] In another example of the metal joint of the present invention, the metal body has a tapered shape in which the outer diameter expands toward the bent portion.

[0020] In another example of the metal joint of the present invention, the metal body further includes a flange portion that protrudes so that the inner diameter narrows at the bent portion.

[0021] In another example of the metal joint of the present invention, a plurality of bent portions are formed in the middle of the groove.

[0022] In another example of the metal joint of the present invention, the metal body has a two-stage tapered shape in which the taper angle relative to the imaginary axis becomes larger at one end and the other end.

[0023] In another example of the metal joint of the present invention, the one material includes wood and concrete, and the other material includes wood and concrete. [Effects of the Invention]

[0024] With the joining metal fitting of the present invention, when the joining metal fitting is screwed into one material and the other material from both ends, a force acts on the end above the bend and the end below the bend to rotate in opposite directions, so that rotation stops near the bend, making it easy to join structural members together.

[0025] When the joining metal fitting described in claim 2 is screwed into one material and the other material from both ends of the joining metal fitting, the forces tending to rotate in opposite directions are the same at the end above the bend and the end below the bend, so rotation stops near the bend, making it easy to join structural members together.

[0026] When the joining metal fitting described in claim 3 is screwed into one material and the other material from both ends of the joining metal fitting, the resistance to rotation of the joining metal fitting is greatest at the bend, so that rotation stops near the bend, making it easy to join structural members together.

[0027] When the metal joint described in claim 4 is screwed into one material and the other material from both ends of the metal joint, the wood abuts against the flange portion, preventing the screwing, so that rotation stops near the bend, making it easy to join structural members together.

[0028] When the joining metal fitting described in claim 5 is screwed into one material and the other material from both ends of the joining metal fitting, the resistance to rotation of the joining metal fitting increases at multiple bends, so that rotation stops near the bends, making it easy to join structural members together.

[0029] In the metal joint described in claim 6, the taper angle at the end of the metal body is smaller than the taper angle at the bent portion, so that both ends have a shape that makes them easier to screw into structural members.

[0030] The metal joint described in claim 7 can be applied to structures made of wood and concrete, making it a highly versatile metal joint. [Brief explanation of the drawings]

[0031] [Figure 1] 1 is a perspective view of a metal joint according to a first embodiment of the present invention; [Figure 2] Front view of the metal joint shown in Figure 1. [Figure 3] Plan view of the metal joint shown in Figure 1. [Figure 4] Cross-sectional view of line IV-IV shown in Figure 2. [Figure 5] Schematic cross-sectional view showing the use of the metal joint shown in Figure 1. [Figure 6] Schematic cross-sectional view showing different usage states of the metal joint in Figure 1. [Figure 7] Schematic cross-sectional view showing different usage states of the metal joint in Figure 1. [Figure 8] Schematic cross-sectional view showing different usage states of the metal joint in Figure 1. [Figure 9] Schematic diagram showing another embodiment of the metal joint of the present invention. [Figure 10] FIG. 1 is a diagram showing the use of a conventional metal joint shown in Patent Document 1. [Figure 11] FIG. 1 is a diagram showing the use of a conventional metal joint shown in Patent Document 2. DETAILED DESCRIPTION OF THE INVENTION

[0032] The details of the metal joint according to the present invention will be described below with reference to the accompanying drawings: Fig. 1 is a perspective view of a metal joint according to a first embodiment of the present invention shown as an example, Fig. 2 is a front view of the metal joint shown in Fig. 1, Fig. 3 is a plan view of the metal joint shown in Fig. 1, Fig. 4 is an end view of the IV-IV line shown in Fig. 2, and Fig. 5 is a schematic cross-sectional view showing the state of use of the metal joint shown in Fig. 1.

[0033] The metal joint 1 has a metal body 10 for joining one member 21 and a counterpart member 22 that are joined opposite to each other. The one member 21 and the counterpart member 22 are rectangular members with square cross sections, for example, 105 mm square or 120 mm square.

[0034] 1, the metal body 10 has a hollow cylindrical shape that is open from one end 4 to the other end 5, and has a tapered shape in which the outer diameter expands toward the center point in the axial direction (the direction from one end 4 to the other end 5). In addition, the metal body 10 has at least one groove 11 (grooves 11a to 11p) formed in the surface of its side surface 15 in the circumferential direction from one end 4 to the other end 5.

[0035] 1 to 3, sixteen grooves 11 are formed on the surface of the side surface 15 of the metal body 10. In a front view, the grooves 11 are formed so as to be inclined with respect to the imaginary axis 3 of the metal body 10, and have a dogleg shape in a front view, bending in the opposite direction midway. More specifically, the grooves 11 include a bending portion 12 (bending portions 12a to 12p) that bends with a changing angle of inclination, a first portion 13 (first portions 13a to 13p) that extends linearly with the same width from one end 4 to the bending portion 12, and a second portion 14 (second portions 14a to 14p) that bends in the opposite direction at the bending portion 12 and extends linearly with the same width to the other end 5. In a plan view, as shown in FIG. 3, the grooves 11 are sandwiched between two spaced apart protrusions 19a and 19b so as to have an inclined, approximately U-shaped shape.

[0036] If the direction perpendicular to the axial direction of the hardware body 10 is taken as the horizontal direction, the first portion 13 and the second portion 14 extend symmetrically with respect to an imaginary horizontal plane 2 passing through the bent portion 12. In this embodiment, the angle (inclination angle) θ1 between the first portion 13 and the imaginary axis 3 at one end is set to approximately 30 degrees. The angle (inclination angle) θ2 between the second portion 14 and the imaginary axis 3 at the other end is set to approximately 30 degrees. The angle θ3 between the first portion 13 and the second portion 14 is set to approximately 120 degrees. The width W of the groove 11 is set to 7 mm. The effects of this configuration will be described later.

[0037] The protrusions 19 (protrusions 19a to 19p) are configured so that the protrusion length D from the groove 11 continuously increases toward the bent portion 12. Accordingly, the outer diameter L1 of the outer edge shape of the metal body 10 has a tapered shape that bulges toward the bent portion 12. When viewed from the front in a direction perpendicular to the direction connecting the one end 4 and the other end 5, the taper angle θ4 of the protrusion 19c on the one end 4 side with respect to the imaginary axis 3 is set to approximately 3 degrees. Furthermore, the taper angle θ5 of the protrusion 19c on the other end 5 side with respect to the imaginary axis 3 is set to approximately 3 degrees. The effects of this configuration will be described later. In this embodiment, the outer diameter L1 at the end of the metal body 10 is set to 53 mm, and the outer diameter L5 at the bent portion 12 is set to 60 mm.

[0038] Referring to Figures 3 and 4, the hardware body 10 further includes a flange portion 18 that protrudes so that the inner diameter L2 narrows at the bent portion 12, a first tapered portion 16 that extends further in the axial direction from one end portion 4, and a second tapered portion 17 that extends further in the axial direction from the other end portion 5.

[0039] The flange portion 18 has a doughnut shape with a circular opening formed in the center. The diameter L3 of the opening is set to 30 mm, and the thickness L4 of the flange portion is set to 5 mm. The effects of this configuration will be described later.

[0040] The first tapered portion 16 has a taper angle θ6 relative to the imaginary axis 3 set to approximately 20 degrees. The second tapered portion 17 has a taper angle θ7 relative to the imaginary axis 3 set to approximately 20 degrees. The taper angle θ6 of the first tapered portion 16 is larger than the taper angle θ4 of the protruding portion 19c of the metal body 10. The taper angle θ7 of the second tapered portion 17 is larger than the taper angle θ5 of the protruding portion 19c of the metal body 10. In other words, the metal joint 1 has a two-stage tapered shape in which the taper angles θ6 and θ7 relative to the imaginary axis 3 are even larger at the one end 4 and the other end 5. The effects of this configuration will be described later.

[0041] In this embodiment, the grooves 11 do not strictly reach the ends of the first tapered portion 16 and the second tapered portion 17. Although it is desirable for the grooves 11 to reach both ends, the grooves 11 do not necessarily have to reach both ends of the metal body 10, and may be interrupted halfway through or before the first tapered portion 16 and the second tapered portion 17. In the present invention, the grooves 11 formed from one end 4 to the other end 5 include both grooves that reach the ends of the first tapered portion 16 and the second tapered portion 17, and grooves that do not reach the ends of the first tapered portion 16 and the second tapered portion 17 but are, for example, tapered.

[0042] Next, a method of using the metal joint 1 will be described.

[0043] Referring to FIG. 5(1), when joining one member 21 and the counterpart member 22 together using the connecting metal fitting 1, a pilot hole is first drilled in advance at a position where the surface of the one member 21 and the surface of the counterpart member 22, which are in surface-to-surface contact, face each other. This serves as a guide when installing the connecting metal fitting 1, making positioning easier. The size of the pilot hole is set so that its diameter is approximately the same as the inner diameter of the connecting metal fitting 1 and its depth is half or less of the axial length of the connecting metal fitting 1. This drills a volume equivalent to at least a portion of the volume of the connecting metal fitting 1, so that even when the connecting metal fitting 1 is screwed in and a compressive force is applied to the wood, generating a restoring force, the contact surfaces of the one member 21 and the counterpart member 22 can be joined without separating. Note that the size and shape of the pilot hole are not limited to those described above, and it may have other diameters and depths, or may have other shapes, such as a donut shape.

[0044] Then, the joining metal fitting 1 is placed at the position of the prepared hole of the counterpart member 22, and the prepared hole of the one member 21 is aligned with the position facing the prepared hole of the counterpart member 22, and the one member 21 is pressed against the counterpart member 22. Then, because the metal body 10 has a hollow cylindrical shape, a shear force is applied to the one member 21 and the counterpart member 22, and the joining metal fitting 1 is screwed in from both ends. This makes it possible to easily join the structural members (one member and the counterpart member) together.

[0045] Joining pieces of wood together is not limited to vertical joining, but can also be done horizontally, as shown in Figure 5(2). Furthermore, by joining pieces of wood together vertically and horizontally, as shown in Figure 5(3), large-section pieces of wood can be created from square timbers with cross-sections of 105mm or 120mm. Compared to conventional slender wood screws with diameters of approximately 6mm or 8mm, the shear resistance is increased, allowing for a stronger connection between pieces of wood. Furthermore, while conventional wood screws are driven from the outside of the wood, leaving the heads exposed on the surface of the wood, the metal joint 1 does not expose the heads on the surface of the wood, improving the aesthetic appearance of the joint. Furthermore, because the metal joint 1 is not exposed on the surface of the wood after joining, the joined wood can be planed, improving the precision of the finish.

[0046] Here, the effect of the grooves 11 will be explained.

[0047] As described above, the connecting metal 1 has at least one groove 11 formed in the circumferential direction of its side surface 15. The groove 11 also includes a first portion 13 extending from one end 4 to the bent portion 12 and a second portion bending in the opposite direction at the bent portion 12 and extending to the other end 5. With this configuration, when the connecting metal 1 is screwed in from both ends, the first portion 13 generates a force tending to rotate clockwise. Meanwhile, the second portion 14 is formed so as to be bent in the opposite direction at the bent portion 12 and have a reverse thread, and therefore generates a force tending to rotate counterclockwise. In other words, a force tending to rotate counterclockwise acts on the first portion 13 and the second portion 14. When the connecting metal 1 is further screwed in in this state, the force tending to rotate counterclockwise is maximized at the bent portion 12, which is bent and bent in the opposite direction relative to the first portion 13. This makes it difficult for the first portion 13 of the connecting metal 1 to further penetrate into the one member 21, and it also makes it difficult for the second portion 14 to further penetrate into the counterpart member 22. Therefore, the rotation stops near the bent portion 12, and the pieces of wood can be easily joined together.

[0048] As described above, the groove 11 extends such that the first portion 13 and the second portion 14 are symmetrical with respect to the imaginary horizontal plane 2 passing through the bent portion 12. With this configuration, when the one member 21 and the counterpart member 22 are screwed into the metal joint 1 from both ends, the forces tending to rotate the first portion 13 and the second portion 14 in opposite directions are the same. This causes the first portion 13 and the second portion 14 to rotate in the same manner, enabling stable drilling into the one member 21 and the counterpart member 22. That is, drilling into the one member 21 from the one end 4 side of the metal body 10 to the bent portion 12 and drilling into the counterpart member 22 from the other end 5 side of the metal body 10 to the bent portion 12 simultaneously is possible, resulting in rotation stopping at the center of the metal body 10. At this time, the bent portion 12 is located at the boundary between the one member 21 and the counterpart member 22. The upper end side of the bent portion 12 is completely buried in the one member 21, and the lower end side of the bent portion 12 is completely buried in the counterpart member 22. In this way, the metal joint 1 can be completely buried in the one member 21 and the counterpart member 22, which allows for efficient construction.

[0049] After joining, the presence of at least one groove 11 in the circumferential direction generates a greater rotational resistance than when no groove 11 is formed. In this embodiment, multiple grooves are formed at equal intervals in the circumferential direction, thereby generating uniform rotational resistance in the metal body 10 and ensuring stable joining. Furthermore, the groove 11 is formed so that the first portion 13, the bent portion 12, and the second portion form a V-shaped groove. Unlike the spiral shape of a normal screw, the groove 11 does not rotate and loosen, and remains in the joined position. This prevents the joint metal 1 from rotating and stabilizes the joined state. Furthermore, even when a force is applied to the joint metal 1 in the pull-out direction, the presence of multiple V-shaped grooves 11 formed at predetermined intervals in the circumferential direction generates pull-out resistance, improving the reliability of the joined state. Furthermore, the presence of the bent portion 12 that bends in the opposite direction from the first portion 13 maximizes the pull-out resistance at the bent portion 12, further improving the reliability of the joined state.

[0050] As described above, the hardware body 10 has a tapered shape in which the outer diameter expands toward the bent portion 12. This causes the shear force acting on the wood to increase as it advances from both ends toward the bent portion 12. The shear force is then maximized at the bent portion 12, resulting in rotation stopping near the bent portion 12. Furthermore, the protruding length D of the convex portion 19 relative to the groove 11 continuously increases toward the bent portion 12, so that the resistance to rotation of the connecting hardware 1 is maximized at the bent portion 12, causing rotation to stop near the bent portion 12, facilitating the joining of the structural members (one member and the other member) to be easily joined together. Furthermore, the hardware body 10 has a two-stage tapered shape, so that the taper angle relative to the imaginary axis 3 at the end of the connecting hardware 1 is larger than the taper angle at the side surface 15, making it easier to screw in from both ends.

[0051] As described above, by providing the flange portion 18 that protrudes so that the inner diameter narrows at the bent portion 12, when the one member 21 hits the upper surface of the flange portion 18, rotation resistance occurs, making it impossible to advance the excavation any further. Also, when the counterpart member 22 hits the lower surface of the flange portion 18, rotation resistance occurs, making it impossible to advance the excavation any further. In this way, the flange portion 18 hinders screwing, so rotation stops near the bent portion 12. This prevents the connecting metal 1 from being positioned biased toward one of the pieces of wood, and the connecting metal 1 is evenly positioned on the one member 21 and the counterpart member 22, making it easy to join the structural members (one member and the counterpart member) together.

[0052] Next, an example of use of the metal joint 1 shown in FIG. 1 will be described.

[0053] FIG. 6 is a schematic cross-sectional view showing a different state of use of the metal joint of FIG.

[0054] Referring to Figure 6, square timbers 23 can be joined with metal joints 1 to form a bearing wall 24. First, the short sides of the square timbers 23 are placed on a horizontal surface, and the long sides are joined together with metal joints. Four square timbers are joined in this manner.

[0055] FIG. 7 is a schematic cross-sectional view showing a different state of use of the metal joint of FIG.

[0056] Referring to Fig. 7, square timbers 25 can be joined with metal joints 1 to be used as beams 26. First, the longitudinal faces of square timber 25a are placed on a horizontal surface and the short-side faces are joined together, and then square timber 25b is placed from above and the longitudinal faces are joined with metal joints, thereby joining multiple square timbers 25 in the vertical and horizontal directions.

[0057] Next, an example of use in which either one or both of the one material and the counterpart material are made of a material other than wood will be described.

[0058] FIG. 8 is a schematic cross-sectional view showing a different state of use of the metal joint of FIG.

[0059] Referring to FIG. 8(1), the connecting hardware 1 can also be used to join existing wooden columns 61, 62 and beams 63, 64 (one member) to a concrete retrofit wall 60 (the other member) when forming the retrofit wall 60 for seismic retrofitting. First, the connecting hardware 1 is attached to the existing columns 61, 62. More specifically, the connecting hardware 1 is screwed into the sides of the columns 61, 62 and stopped at the bends 12. The connecting hardware 1 is similarly screwed into the beams 63, 64 and stopped at the bends 12. Next, formwork is installed in a predetermined position, and concrete 65 is poured and allowed to harden. The concrete 65 is then fixed to the columns 61, 62 and beams 63, 64 by the connecting hardware 1. In this way, the connecting hardware 1 can easily join structural members (wood and concrete) together. Furthermore, compared to conventional methods of joining by placing thin reinforcing bars, the outer diameter of the joining hardware 1 is larger and a groove with a bent section is formed on its surface, making it less likely to come loose even if pulled after being fixed in the concrete, resulting in a stable joining state.

[0060] The metal joint 1 can also be used to join an existing concrete beam or pillar (one member) to a later-installed wall (the other member). First, a pilot hole is drilled in the existing beam or pillar at the position where the metal joint 1 will be attached. The size of the pilot hole is set so that its diameter is approximately the same as the inner diameter of the metal joint 1 and its depth is half or less of the axial length of the metal joint 1. Next, the metal joint is screwed into the pilot hole and stopped at the bent part. Then, concrete 65 is poured in using the same procedure as for wooden pillars and beams to form the later-installed wall.

[0061] Furthermore, rebar may be placed inside the retrofitted wall, allowing the wall's rigidity and strength to be adjusted.

[0062] The retrofit wall may also be made of a material other than concrete, such as wood. In this case, a gap is provided between the upper and lower ends of the wood and the beam, and the side of the wood is pressed against the side of the column, whereby the metal connector is screwed into the wooden wall. Furthermore, the retrofit wall may be made of a combination of concrete and wood. Thus, in the metal connector of the present invention, the one material includes wood and concrete, and the other material includes wood and concrete. This configuration allows for joining not only wood to wood, but also various types of structural members, such as wood and concrete, or concrete to concrete, depending on the required performance of the building. Therefore, since it can be applied to structures made of wood and concrete, it is a highly versatile metal connector.

[0063] Furthermore, the method of using the metal joint of the present invention for retrofitting walls is not limited to the above-mentioned embodiment. For example, when constructing a new building, metal joints may be screwed into the pillars and beams at the same time as they are installed, and a wall made of concrete or the like may be formed.

[0064] Referring to Figure 8(2), the retrofit wall 66 may have an opening 67 for a window, door, or the like. In this case, the metal joint 1 is not attached to the beam 64 near the portion where the opening 67 is formed, but the metal joint 1 is attached to the columns 61, 62 and beam 63 in the same manner as in Figure 8(1).

[0065] Referring to Figure 8(3), the post-attached wall may be sleeve walls 68 (68a, 68b). When forming the sleeve wall 68a, the metal joints 1 are attached to three of the four sides of the sleeve wall 68a (parts of the column 61 and the beams 63 and 64) in the same manner as in Figure 8(1).

[0066] The concrete to be attached to the retrofit wall may be formed from steel frame members or the like via concrete, grout, or the like.

[0067] Next, a modified example of the metal joint 1 shown in FIG. 1 will be described.

[0068] FIG. 8 is a schematic diagram showing another embodiment of the metal joint of the present invention.

[0069] Since the metal joints according to these other embodiments have basically the same structure as the metal joint according to the first embodiment described above, the following description will focus on the differences.

[0070] Referring to Figure 9 (1), the connecting hardware 30 has eight grooves 32 formed on the side of the hardware body 31. By configuring it in this way, the number of grooves is reduced, thereby reducing manufacturing costs. The number of grooves is not limited to 16 or 8, and may be any number greater than or equal to one. The present invention includes grooves having one or more grooves. It is preferable that the circumferential spacing can be equally divided. In this case, a force acting to rotate in the reverse direction acts evenly on the hardware body 10, so that rotation can be more reliably stopped near the bent portion 12.

[0071] 9(2), the metal joint 35 has 16 grooves 37 formed on the side of the metal body 36, and the inclination angle θ8 of each groove 37 is set to be approximately 50 degrees. By configuring the inclination angle to be large in this way, the rotational resistance of the metal joint can be adjusted to suit the hardness of the wood.

[0072] 9(3), a metal joint 40 has 16 grooves 42 formed on the side of a metal body 41, and each groove 42 includes a portion that extends vertically between a first portion 43 and a second portion 44. In this way, the groove may be formed by combining an inclined portion and a vertically extending portion.

[0073] 9(4), the metal joint 45 has 16 grooves 47 formed on the side of the metal body 46. Two bent portions (first bent portion 48 and second bent portion 49) are formed midway through the grooves 47. In this way, the present invention also includes those having multiple bent portions and in which the grooves 47 are formed in two or three stages.

[0074] 9(5), the angle θ9 of the end of the two-stage tapered metal joint 50 is set to be even larger. This configuration makes it easier for the end of the metal joint to bite into the wood when screwing in, making joining even easier.

[0075] Referring to Figure 9 (6), the metal joint 55 has ten grooves formed on the side of the metal body 56. The grooves include two types of grooves 57 and 58 with different widths. In this way, some of the grooves may be formed to have different widths.

[0076] In the above-described embodiments, except for the embodiment shown in Fig. 8, the one member and the counterpart member are 120 mm square timbers, but they may be timbers of other sizes or shapes. Furthermore, they may be wood of other shapes as long as they have a portion that allows surface contact. Furthermore, they may be structural members made of materials other than wood, such as concrete. Examples of such materials include earth, plaster, resin, and ceramic materials.

[0077] Furthermore, in each of the above-described embodiments, the one material and the counterpart material are joined facing each other and are basically fixed by surface contact, but as necessary, they may be fixed with a gap between them without surface contact.

[0078] Furthermore, in each of the above embodiments, the first portion and the second portion extend symmetrically with respect to the imaginary horizontal plane passing through the bent portion, but they do not have to be symmetrical with respect to the imaginary horizontal plane as long as they are bent in opposite directions.

[0079] Furthermore, in each of the above embodiments, the metal body has a tapered shape, but it does not have to have a tapered shape, for example, it may extend parallel to the axial direction.

[0080] Furthermore, in each of the above embodiments, the convex portion of the metal body is set to a specific taper angle, but other taper angles are also possible. For example, the taper angle can be set in the range of 1 to 45 degrees.

[0081] Furthermore, in each of the above embodiments, the outer and inner diameters at the ends of the metal body and the outer diameter at the bent portion are set to specific lengths, but other lengths are also possible. For example, the outer and inner diameters at the ends and the outer diameter at the bent portion can be appropriately set within the range of 10 to 200 mm depending on the use situation so that the inner diameter at the end < the outer diameter at the end < the outer diameter at the bent portion.

[0082] Furthermore, although the above-described embodiments have flanges, the flanges may be omitted.

[0083] Furthermore, in each of the above embodiments, the flange portion has a doughnut shape that protrudes from the entire periphery, but it may have another shape as long as it protrudes from at least a portion.

[0084] Furthermore, in each of the above embodiments, the metal joint has a two-stage tapered shape, but the first tapered portion and the second tapered portion may be omitted.

[0085] Furthermore, although the grooves are set to a specific width in each of the above embodiments, they may be set to other widths. For example, the groove width can be set in the range of 1 to 90 mm.

[0086] Furthermore, in each of the above embodiments, the grooves are formed in a straight line, but they may be wavy or meandering, and may not be straight.

[0087] Furthermore, in each of the above embodiments, the grooves are formed with a constant width, but the grooves may be formed so that the width varies along the groove, such as by gradually increasing the width. In this case, the center line of the width is assumed, and the angle of the center line relative to the imaginary axis is defined as the inclination angle of the groove.

[0088] Furthermore, although the grooves are formed to have a specific inclination angle in each of the above embodiments, other inclination angles are also possible. For example, the inclination angle of the grooves can be set in the range of more than 0 degrees and less than 90 degrees.

[0089] Furthermore, in each of the above embodiments, the joining metal may be formed by other methods such as casting, in addition to cutting. Also, the groove is formed by cutting the portion that forms the groove, but the groove may be formed by forming two protrusions that extend apart. [Explanation of symbols]

[0090] 1, 30, 35, 40, 45, 50, 55...Metal joints 2...Virtual horizon 3...Virtual axis 4...One end 5...Other end 10, 31, 36, 41, 46, 56...Hardware body 11, 32, 37, 42, 47, 57, 58...Groove 13, 48, 49...Bends 14, 43...First part 15, 44...Second part 18...Flange 21...One side material 22...Other material In addition, the same reference numerals in each drawing indicate the same or corresponding parts.

Claims

1. A metal joint having a metal body for joining one member and a counterpart member that are joined opposite to each other, The metal body is It has a hollow cylindrical shape that is open from one end to the other end, At least one groove is formed in the circumferential direction from the one end to the other end, The groove is formed so as to be inclined with respect to the virtual axis of the metal body, and a bending portion is formed so as to bend while changing the inclination angle; a first portion extending from the one end to the bent portion; A metal joint comprising a second portion that bends in the opposite direction at the bent portion and extends to the other end.

2. If the direction perpendicular to the axial direction of the metal body is the horizontal direction, The metal joint according to claim 1 , wherein the first portion and the second portion extend symmetrically with respect to an imaginary horizontal plane passing through the bent portion.

3. The metal joint according to claim 1 or 2, wherein the metal body has a tapered shape in which the outer diameter expands toward the bent portion.

4. The metal joint according to claim 1 or claim 2, wherein the metal body further comprises a flange portion that protrudes so that the inner diameter narrows at the bent portion.

5. The metal joint according to claim 1 or 2, wherein a plurality of the bent portions are formed midway along the groove.

6. The metal joint according to claim 3, wherein the metal body has a two-stage tapered shape in which the taper angle relative to the imaginary axis becomes larger at the one end and the other end.

7. The one material includes wood and concrete, The metal joint according to claim 1 or 2, wherein the counterpart material includes wood or concrete.

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