Holdown hardware

Abstract

Hold-down hardware attached to a side surface of a vertical structural member for connecting the structural member to another member via a bolt, the hold-down hardware having high flexural rigidity and high yield strength by dispersing and transmitting a large pulling force to the vertical member SOLUTION: This hold-down hardware 10 has a base part 11 fixed by abutting on a structural member 3, and a bolt locking part 12 fixed to the base part and locking one end of an anchor bolt 4, and two groove-like parts 13 are formed in parallel in the substantially vertical direction in the base part 11. The bolt locking part 12 is formed by bending a steel plate material, and is fixed to each of the two groove-like parts 13 so as to cover a part of the groove-like part.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a hold-down hardware that is used in parts of buildings and the like where lift may act on structural members, and that functions to prevent the structural member from moving upward away from other structural members that support it, and to pull both structural members together. [Background technology]

[0002] In structures using vertical structural members such as columns, upward lift forces may act on some of the structural members during earthquakes or strong winds. Many wooden structures use hold-down hardware to resist such lift forces, such as those shown in Patent Documents 1 and 2. These hold-down hardware are attached to the sides of vertical structural members, and one end of a bolt is fastened to the hold-down hardware, with the other end connected to another structural member, thereby connecting the structural member to another structural member. In both of the examples described in Patent Documents 1 and 2, the hold-down hardware is attached to a wooden column supported on a foundation, and the other end of the fastened bolt is connected to the foundation to prevent the column from coming loose upward.

[0003] In addition, hold-down hardware is also used to connect columns on the upper floors with columns on the lower floors to reduce the lift force acting on the columns on the upper floors, or to reduce the lift force acting on cross members supported on the columns. Also, vertical members are not limited to columns, but can also be used for wide wall-like members. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2009-243184 [Patent Document 2] Patent Publication No. 2008-175049 Summary of the Invention [Problem to be solved by the invention]

[0005] As buildings and other structures become larger and taller, the lift generated in some of their structural members can become significant. Accordingly, hold-down hardware must be able to withstand such large lift forces. The hold-down hardware disclosed in Patent Document 2 has two bolt locking sections, each of which is vertically positioned, to which a series of bolts are locked. This allows the pulling force that suppresses the lift to be distributed from the two bolt locking sections and act on the column, making it possible to withstand large lift forces.

[0006] However, in the hold-down hardware described in Patent Document 2, the pulling force is transmitted to the column from a series of bolts, and the pulling force acts along the same vertical axis. Furthermore, the screws used to secure the hold-down hardware are arranged along the same axis on the side of the column, so the pulling force is transmitted to the column in a concentrated manner near the same axis. This can result in insufficient strength of the hold-down hardware attached to the column.

[0007] Furthermore, because the axis of the bolt that engages the hold-down hardware is eccentric to the surface that attaches the hold-down hardware to the column, a bending moment is generated in the hold-down hardware in the axial direction of the column when a pulling force is applied. As the pulling force increases, the bending moment also increases, causing bending deformation in the hold-down hardware, and a force acts on part of it that tries to separate it from the mounting surface of the column. This can cause a large load to act on parts of the screws that attach the hold-down hardware to the column, reducing its strength.

[0008] The present invention has been made to solve the above-mentioned problems, and its purpose is to provide a hold-down hardware that has high bending rigidity and has high strength at the attachment portion by dispersing and transmitting a large pulling force to a vertical member. [Means for solving the problem]

[0009] In order to solve the above problem, the invention of claim 1 provides a hold-down hardware that is attached to the side of a vertical structural member and is used to connect the structural member to another member via a bolt, the hold-down hardware having a base that abuts and is fixed against the structural member, and a bolt locking portion that is fixed to the base and to which one end of the bolt is locked, the base having two parallel groove-like portions formed in an approximately vertical direction, the bolt locking portion being formed by bending steel plate material, and being fixed so as to cover a portion of each of the two groove-like portions.

[0010] This hold-down hardware uses two bolts to connect a structural member to another member, providing a strong pulling force in the structural area where a large force acts to separate the members. The two bolts are then locked into the integrated base, distributing and transmitting the pulling force to the structural members. The base, which is attached to the structural member, also has two grooves, giving it high bending rigidity in the vertical direction. Because the base's contact surface with the structural member is eccentric to the central axis of the bolt, a large bending moment occurs in the base when a large pulling force acts. However, the high bending rigidity of the base suppresses bending deformation. This prevents the base from partially separating from the structural member, reducing the load on the screws and other fasteners used for attachment.

[0011] The invention of claim 2 is the hold-down hardware of claim 1, wherein the base is formed by bending steel plate material, and comprises side edge risers in which both substantially vertical edge portions are bent up in a direction away from the abutment surface with the structural member, and convex portions bent up convexly between both side edge risers in a direction away from the abutment surface with the structural member, wherein the groove portions are between each of the side edge risers and the convex portions, and each of the bolt locking portions provided in the two groove portions has one side end fixed to the side edge riser and the other side end fixed to the convex portion.

[0012] This hold-down hardware has two groove-shaped portions, which allows for efficient production of a base with increased bending rigidity, and the highly rigid bolt locking portion can be securely fixed by welding, etc.

[0013] The invention of claim 3 is a hold-down hardware as described in claim 1 or claim 2, wherein the bolt locking portion is bent along a bending line in an approximately vertical direction, so that both sides of the bent portion face each other, and the opposing spacing at a position closer to the bent portion is narrower than the opposing spacing at the position fixed to the base, corresponding to the diameter of the bolt used.

[0014] With this hold-down hardware, the steel plate material of the bolt locking part can be brought close to the bolt, and when a pulling force is transmitted from the bolt to the bolt locking part via the nut or bearing plate, the pulling force is prevented from acting unevenly on the bolt locking part and base. This prevents deformation of the bolt locking part and base and improves their strength.

[0015] The invention of claim 4 is a hold-down hardware as described in claim 1 or claim 2, wherein the bolt locking portion is provided near one end of the base in the vertical direction, and a plurality of small holes for fixing the base to the structural member are provided from near the position where the bolt locking portion is provided to the other end side.

[0016] With this hold-down hardware, if the bolt that is to be engaged with the bolt engaging portion is fixed in advance, for example, even if the bottom end is embedded in the concrete of the foundation, the work of attaching the base to the structural member can be easily performed without being hindered by the bolt.

[0017] The invention of claim 5 is a hold-down hardware as described in claim 1 or claim 2, wherein the bolt locking portion is provided in the middle between both ends of the base in the vertical direction, and a plurality of small holes for fixing the base to the structural member are provided from near the position where the bolt locking portion is provided to both ends.

[0018] In this hold-down hardware, by providing the bolt locking portion in the middle of the base, the bending moment of the base, which is caused by the eccentricity between the attachment surface of the base to the structural member and the central axis of the bolt, can be distributed to both the top and bottom of the bolt locking portion, suppressing bending deformation and reducing the load on the screws, etc. that attach the base to the structural member. In addition, the shear force generated in the screws, etc. by the pulling force is also distributed to both the top and bottom of the bolt locking portion, preventing the load from concentrating on certain screws, etc.

[0019] The invention of claim 6 is a hold-down hardware as described in claim 2, wherein the convex portion has a flat portion at the top of the convex portion that is approximately parallel to the mounting surface to the structural member.

[0020] In this hold-down hardware, by providing a flat portion on the convex portion, the cross-sectional area of ​​the base can be increased at a position away from the contact surface with the structural member, thereby effectively increasing the bending rigidity. [Effects of the Invention]

[0021] As explained above, the hold-down hardware of the present invention can distribute the large pulling force from the two bolts and transmit it to the vertical member. In addition, the base has high bending rigidity in the axial direction of the attached structural member, reducing the load on the screws and other fasteners used to attach it to the structural member. This results in high bearing strength at the attachment point to the structural member. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a schematic perspective view showing the use state of a hold-down hardware according to one embodiment of the present invention. FIG. [Figure 2] 2A and 2B are a front view, a side view, and a plan view of the hold-down hardware shown in FIG. 1. [Figure 3] FIG. 3 is an enlarged plan view of the hold-down hardware shown in FIG. 2. [Figure 4] FIG. 3 is a schematic perspective view showing another example of use of the hold-down hardware shown in FIG. 2. [Figure 5] FIG. 3 is a schematic perspective view showing another example of use of the hold-down hardware shown in FIG. 2. [Figure 6] 6 is a schematic side view showing the joint between the two structural members shown in FIG. 5, and a plan view and a side view of a screw used in this joint member. [Figure 7] 10A and 10B are a front view, a side view, and a plan view of a hold-down hardware according to another embodiment of the present invention. [Figure 8] 8 is a schematic perspective view showing the hold-down hardware shown in FIG. 7 in use. DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a schematic perspective view showing an example of a structure in which a wooden pillar is connected to a foundation using a hold-down hardware according to one embodiment of the present invention. Fig. 2 shows a front view, a side view, and a plan view of the hold-down hardware used in this structure, and Fig. 3 is an enlarged plan view. In this structure, a base 2 is fixed onto a concrete foundation 1, and a pillar 3 is erected on top of that. A hold-down hardware 10 according to the present invention is fixed to the side of the wooden pillar 3, and the upper end of an anchor bolt 4, the lower part of which is embedded in the concrete foundation 1, is engaged with this hold-down hardware 10.

[0024] The anchor bolt 4 has its lower end embedded in the foundation 1 and has a large pull-out resistance.It is inserted into a vertical through hole formed in the base 2 and engaged with a hold-down hardware 10. The base 2 is made of wooden material supported horizontally on the foundation 1 and is firmly fixed to the foundation 1 by bolts 5. The column 3 is erected on the base 2 and connected to the foundation 1 via a hold-down hardware 10 fixed to the side and an anchor bolt 4 engaged therewith. This prevents the column 3 from being displaced upward when an upward lift force acts on the column 3 during an earthquake, strong wind, etc. Therefore, the part where the hold-down hardware 10 is attached to the column 3, the anchor bolt 4, and the part where the anchor bolt 4 is embedded in the foundation 1 have sufficient strength to be able to suppress the lift force acting on the column 3.

[0025] As shown in FIG. 2, the hold-down hardware 10 has a base 11 that is fixed in contact with the side of the pillar, and a bolt locking portion 12 that is fixed to the base 11. The base 11 is formed by bending a steel plate, and two groove-like portions 13 are formed parallel to each other in the axial direction of the column 3, i.e., in the vertical direction. These groove-like portions 13 are formed by side edge rising portions 14, which are formed by bending up both side edge portions in the direction along the axis so that they are approximately perpendicular to the mounting surface of the column 3, and a convex portion 15, which is formed by making the central portion in the width direction of the column 3 convex so as to rise from the mounting surface of the column 3. In other words, the side edge rising portions 14 and the convex portion 15 are continuous in the axial direction of the column 3, and the groove-like portions 13 are formed between the side edge rising portions 14 on both sides and the central convex portion 15.

[0026] A plurality of small circular holes 17 are formed in the portion 16 between the side edge rising portion 14 and the convex portion 15 that abuts against the pillar, and the base 11 can be fixed to the pillar 3 by screwing screws 18 into the pillar through these small circular holes 17. In addition, a bolt that penetrates the pillar 3 can be used instead of the screw 18.

[0027] The bolt locking portions 12 are provided independently in each of the two groove-shaped portions 13 near the lower end of the base 11. These bolt locking portions 12 are formed by bending a rectangular steel plate along a vertical bending line, with both side edge portions 21a, 21b facing each other, as shown in Fig. 3. These both side edge portions 21a, 21b are inserted into the groove-shaped portions 13 of the base 11 and supported so as to cover the groove-shaped portions 13, with one side edge portion 21a fixed to the rising side edge portion 14 and the other side edge portion 21b fixed to the convex portion 15 by welding.

[0028] The bolt locking portion 12 has a predetermined length in the axial direction of the pillar 3, and its planar shape is bent at three vertical bending lines A, B, and C as shown in Figure 3, with the two sides of the portion where the three bending lines are provided facing each other. The distance between the facing portions 22 near the bent position is set slightly larger than the diameter of the anchor bolt 4. The tip ends on both sides of the opposing portion 22, which corresponds to the diameter of the anchor bolt 4, i.e., the side edge portions 21a, 21b that are inserted into the groove-shaped portions and fixed, are bent so that the opposing gap is enlarged, and the opposing portions face each other almost parallel with the enlarged gap.

[0029] 1 and 3, the upper end of the anchor bolt 4 is locked to this bolt locking portion 12 with a nut 6. The anchor bolt 4 is inserted from below through the portion where the bolt locking portion 12 is attached so as to cover the groove-shaped portion 13, and is locked in a state where it is positioned at the opposing portion 22 close to the bent position of the bolt locking portion 12. The vertical dimension of the bolt locking portion 12 is set to a dimension sufficient to transmit the downward pulling force acting from the anchor bolt 4 to the base portion 11 without being significantly deformed by the pulling force.

[0030] In this way, in the support structure for the lower end of a column using the hold-down hardware 10 according to the present invention, when an upward lift force acts on the lower end of the column 3 due to a horizontal force during an earthquake or strong wind, the column 3 is restrained from displacing upward because the column 3 is connected to the foundation 1 via the anchor bolt 4 and the hold-down hardware 10. In this case, two anchor bolts 4 are used in parallel and are fastened to one hold-down hardware 10, so a large restraining force, or pulling force, is exerted, and the large pulling force acts on the column 3 in a dispersed manner.

[0031] Furthermore, the hold-down hardware 10 has two groove-like portions 13 and a large moment of inertia, so even when a large pulling force is applied from the anchor bolt 4, the bending deformation that occurs in the axial direction of the column 3 is kept small. This prevents excessive pull-out force from acting on some of the multiple screws 18 that secure the hold-down hardware 10 to the column 3. Furthermore, by using two anchor bolts 4, when reinforcing bars are placed in the center of the foundation 1, they can be distributed and placed on both sides of the center, allowing for easy placement while avoiding interference between the anchor bolts 4 and the reinforcing bars.

[0032] FIG. 4 is a schematic perspective view showing another example of use of the hold-down hardware according to the present invention. In this example, a beam, cross member 32 such as a crossbeam or cross section is erected on a column 31 of the lower floor, and a hold-down hardware 10 is used in the area where a column 33 of the upper floor is erected on top of that. Two hold-down hardware 10 are used, and one of them, hold-down hardware 10a, is fixed to the top of column 31 on the lower floor with its bolt locking portion 12 positioned on the upper side. The other hold-down hardware 10b is fixed to the lower end of column 33 on the upper floor with its bolt locking portion 12 positioned on the lower side. The lower end of a connecting bolt 34 is locked to the bolt locking portion 12 of hold-down hardware 10a fixed to column 31 on the lower floor, and the upper end is locked to the bolt locking portion 12 of hold-down hardware 10b fixed to column 33 on the upper floor.

[0033] In this example of use, when an uplift force is generated in the column 33 on the upper floor, the column 33 on the upper floor is prevented from moving upward away from the cross member 32, or away from the column 31 on the lower floor together with the cross member 32, by being restrained by the two hold-down hardware 10a, 10b and the two connecting bolts 34.

[0034] Figure 5 shows another example of use of the hold-down hardware 10 shown in Figure 2, in which it is used in a joint where a lift force acts on a cross member 42 supported on a column 41. Figure 6 shows a side view of the joint between the column 41 and the cross member 42 shown in Figure 5, as well as a plan view and a side view of the screw 43 used in this example. In this example of use, the hold-down hardware 10 is fixed to the top of the column 41, and the bolt locking portion 12 is located above the hold-down hardware 10. A connecting bolt 44, whose lower end is locked to the bolt locking portion 12, is inserted into a through-hole in a cross member 42 supported on the column 41, and is locked to the cross member 42 via a bearing plate 45 on the top surface of the cross member 42.

[0035] At the portion of the cross member 42 where the support plate 45 abuts, multiple screws 43 are screwed into the cross member 42, with the top surfaces of their heads at approximately the same height as the top surface of the cross member 42. The support plate 45 abuts against the cross member 42 and also against the heads of the screws 43. As a result, when a large pulling force is applied from the connecting bolts 44, the force is transmitted from the support plate 45 via the screws 43 to deep inside the cross member 42. This prevents the support plate 45 from sinking into the cross member 42 and causing deformation of the cross member 42.

[0036] In addition, lift force may occur on the cross member 42 when an upward force acts from a column on an upper floor, or when lift force occurs at the rear end of the cross member when it is supported in a cantilevered manner, and this method can also be applied to these cases.

[0037] Fig. 7 is a front view, a side view, and a plan view showing another embodiment of the hold-down hardware according to the present invention, and Fig. 8 is a schematic perspective view showing an example of use of the hold-down hardware 50 shown in Fig. 7. Similar to the hold-down hardware 10 shown in FIG. 2, this hold-down hardware 50 includes a base 51 that is attached to a structural member such as a pillar, and a bolt locking portion 52 that is fixed to the base 51 and into which a bolt is locked. The base 51 of this hold-down hardware 50 is formed by bending a steel plate, similar to the one shown in FIG. 2, and has the same cross-sectional shape. However, in this hold-down hardware 50, the bolt locking portion 52 is fixed approximately in the center between both ends of the two groove-shaped portions 53 in the axial direction. The bolt locking portion 52 has the same shape as the hold-down hardware 10 shown in FIG. 2 and is provided so as to cover a portion of each of the groove-shaped portions 53 formed in the base 51. Furthermore, a plurality of small circular holes 54 that penetrate the bottoms of the groove-shaped portions 53 are formed both above and below the position where the bolt locking portion 52 is formed. The hold-down hardware can be fixed to a pillar by inserting screws 55 into these small circular holes 54.

[0038] As shown in Figure 8, such a hold-down hardware 50 is attached to a column 63 supported on a foundation 61 via a base 62, similar to that shown in Figure 2, and its lower end is connected to the foundation 61 via an anchor bolt 64 embedded in the concrete of the foundation 61 and an extension bolt 65 connected to the anchor bolt. This prevents the column 63 from displacing upward when a lift force acts on it. The anchor bolt 64 and extension bolt 65 are joined by a long nut 66 that functions as a connector, but instead of the anchor bolt 64 and extension bolt 65, an anchor bolt that continues from the foundation 61 to the bolt locking portion 52 may be used.

[0039] Furthermore, with this hold-down hardware 50, although the length connecting the anchor bolt 64 and extension bolt 65 from the bolt locking portion 52 to the foundation 61 is somewhat large, the extension bolt 65 is locked at the center of the base 51, and the axes of the anchor bolt 64 and extension bolt 65 are eccentric to the mounting surface of the base 51 to the column 63, so that the bending moment acting on the base 51 acts on both the upper and lower sides of the bolt locking portion 52, thereby reducing bending deformation of the base 51. Therefore, a large pull-out force is prevented from acting on some of the multiple screws 55 that attach the base 51 to the column 63. In addition, the shear force acting on the screws 55 is distributed between the upper and lower screws, preventing the shear force from concentrating on some of the screws. Like the hold-down hardware 10 shown in Fig. 2, this hold-down hardware 50 can also be used to connect a column 31 on a lower floor to a column 33 on an upper floor as shown in Fig. 3. It can also be used to connect the top of a column 41 to a cross member 42 as shown in Fig. 5.

[0040] The hold-down hardware described above is an embodiment of the present invention, and the present invention is not limited to the above-described embodiment, but can be appropriately designed and implemented within the scope of the present invention. Furthermore, the manner of use is not limited to the above-described example, and can be used in various ways in which the hold-down hardware of the present invention can be used. [Explanation of symbols]

[0041] 1: Foundation, 2: Base, 3: Pillar, 4: Anchor bolt, 5: Bolt, 6: Nut, 10: Hold-down hardware, 11: Base, 12: Bolt locking portion, 13: Groove-shaped portion, 14: Side edge rising portion, 15: Convex portion, 16: Portion that contacts the pillar, 17: Small circular hole, 18: Screw, 21: Side edge of bolt locking portion; 22: Opposing portion near the bent position; 31: Lower floor pillar, 32: Cross member, 33: Upper floor pillar, 34: Connecting bolt, 41: Pillar, 42: Cross member, 43: Screw, 44: Connecting bolt, 45: Bearing plate, 50: Hold-down hardware, 51: Base, 52: Bolt locking portion, 53: Groove-shaped portion, 54: Small circular hole, 55: Screw, 61: Foundation, 62: Base, 63: Pillar, 64: Anchor bolt, 65: Extension bolt, 66: Long nut

Claims

1. A hold-down hardware that is attached to the side of a vertical structural member and is used to connect the structural member to another member via a bolt, a base portion that is fixed in contact with the structural member; a bolt locking portion fixed to the base and to which one end of the bolt is locked, The base portion has two parallel groove portions formed in a substantially vertical direction, The bolt locking portion is formed by bending a steel plate material, A hold-down hardware characterized in that it is fixed so as to cover a portion of each of the two groove-shaped portions.

2. The base portion is formed by bending a steel plate material, a side edge raised portion in which both side edges in a substantially vertical direction are bent up in a direction away from the abutment surface with the structural member; a convex portion bent up convexly in a direction away from the contact surface with the structural member between both of the side edge rising portions, The groove-shaped portion is formed between each of the side edge rising portions and the convex portion, A hold-down hardware as described in claim 1, characterized in that each of the bolt locking portions provided in the two groove-shaped portions has one side end fixed to the side edge rising portion and the other side end fixed to the convex portion.

3. The bolt locking portion is bent along a substantially vertical bending line, and has a shape in which both sides of the bent portion face each other, A hold-down hardware as described in claim 1 or claim 2, characterized in that the opposing spacing at a position closer to the bending processing portion is narrower than the opposing spacing at the position fixed to the base, corresponding to the diameter of the bolt used.

4. A hold-down hardware as described in claim 1 or claim 2, characterized in that the bolt locking portion is provided near one end of the base in the vertical direction, and a plurality of small holes are provided from near the position where the bolt locking portion is provided toward the other end for fixing the base to the structural member.

5. A hold-down hardware as described in claim 1 or claim 2, characterized in that the bolt locking portion is provided in the middle between both ends of the base in the vertical direction, and a plurality of small holes are provided from near the position where the bolt locking portion is provided to both ends for fixing the base to the structural member.

6. 3. The hold-down hardware according to claim 2, wherein the convex portion has a flat portion at the top of the convex portion that is approximately parallel to the mounting surface of the structural member.

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