Method for constructing lag screw bolt

Abstract

To provide a method for constructing a lag screw bolt, which facilitates burying work of burying a large-sized lag screw bolt, which applies a large load to a burying tool, into a prepared hole.SOLUTION: A fixed lag screw bolt P1 that is shorter than a predetermined length is buried on a bottom side of a prepared hole Q1. Then, a coupling lag screw bolt P2 with an axial center part passing through is buried. A lag screw bolt P of the predetermined length is constructed in the prepared hole Q1. A fixed bolt R is fixed to the fixed lag screw bolt P1. The lag screw bolt P of the predetermined length buried in the prepared hole Q1 is integrated.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for installing a lag screw bolt, which can install the lag screw bolt according to the required length and diameter when embedding the lag screw bolt in wood.

Background Art

[0002] A lag screw bolt without a hexagonal head is used, for example, in a method for connecting a cross-laminated timber Q (CLT) described in Patent Document 1. This lag screw bolt L is formed such that the valley diameter dimension of the thread is made to match the inner diameter dimension of the pilot hole Q1, and it has the effect of being able to connect the cross-laminated timber Q (CLT) of a wood-steel hybrid structure and the steel material P without using any adhesive. Moreover, it eliminates the need for laborious operations such as counterboring the wood and filling with epoxy resin, which are required when using a general lag screw bolt with a hexagonal head, and it is a component that is extremely effective in shortening the construction period of a wood-steel hybrid structure.

[0003] A dedicated mounting jig used for the operation of embedding this lag screw bolt in the pilot hole Q1 is described in Patent Document 2. This mounting jig includes a tightening bolt body 1 that connects to the female thread portion L3 at the end of the lag screw bolt L, a holding cylinder body 2 used when removing the tightening bolt body 1 from the female thread portion L3 of the lag screw bolt, and a contact plate 3 that abuts against the opening of the pilot hole Q1.

[0004] The usage method of this mounting jig is to screw the tightening bolt body 1 into the female thread portion L3 of the lag screw bolt L with the holding cylinder body 2 and the contact plate 3 attached to the tightening bolt body 1. Then, the lag screw bolt L is embedded by rotating the tightening bolt body 1 until the contact plate 3 abuts against the opening end of the pilot hole Q1. After that, when removing the tightening bolt body 1 from the female thread portion L3 of the embedded lag screw bolt L, the tightening bolt body 1 is configured to be removed while fixing the holding cylinder body 2 with a wrench or the like.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] The lag screw bolt shown in Patent Document 1, like a lag screw bolt having a hexagonal head, does not require wood counterboring or epoxy resin filling work, so the working process can be simplified. However, when a tightening bolt is screwed into the female screw portion 3 recessed at the end of the lag screw bolt L and this bolt is rotated to embed the lag screw bolt L in the pilot hole Q1, the thread of the bolt bites into the female screw portion 3 of the lag screw bolt L and enters a tightened state. As a result, when the tightening bolt is rotated counterclockwise and removed, there has been a problem that the lag screw bolt L comes out together with this bolt.

[0007] Therefore, when embedding the lag screw bolt L without a hexagonal head, it was necessary to use a dedicated mounting jig shown in Patent Document 2. That is, when removing the tightening bolt body 1, the tightening bolt body 1 is removed while fixing the holding cylinder body 2 with a wrench or the like. Therefore, since the lag screw bolt L without a hexagonal head requires the use of a special dedicated tool, it has been difficult to embed the lag screw bolt L only with a normal embedding tool like a lag screw bolt having a hexagonal head.

[0008] Moreover, since the embedding work of the lag screw bolt L without a hexagonal head uses a dedicated tool, the limit of the embedding depth is up to the opening of the pilot hole Q1, and it has been difficult to embed it up to the deep part of the pilot hole Q1. Therefore, there has also been a problem that the range of use of the lag screw bolt L is limited.

[0009] Furthermore, when used in buildings with a wood-steel hybrid structure, etc., the lag screw bolt L tends to be larger in size. However, to embed a large lag screw bolt L into the pilot hole Q1, a large load is imposed on the embedding tool such as an impact wrench. Therefore, at a construction site where a number of large lag screw bolts L are continuously embedded, there was a risk that the embedding tool would break down.

[0010] Therefore, when embedding a large lag screw bolt L into the pilot hole Q1, multiple embedding tools are prepared and used alternately, or the embedding is carried out sequentially with a time gap until the embedding tool cools down.

[0011] Thus, in construction work using a large lag screw bolt L, there was the disadvantage that a lot of time and tools were required to embed the lag screw bolt L. Moreover, if the lag screw bolt L becomes even larger, it is expected that it will be difficult to embed it with a normal embedding tool.

[0012] Therefore, the present invention was created to solve the above problems, and an object thereof is to provide a construction method for a lag screw bolt that facilitates the embedding operation of embedding a large lag screw bolt, which imposes a large load on the embedding tool, into a pilot hole, and enables embedding with a normal embedding tool even if the lag screw bolt becomes even larger.

Means for Solving the Problems

[0013] To achieve the above object, the first means of the present invention is a construction method of a lag screw bolt formed with a bolt body 1 without a hexagonal head to be embedded in a pilot hole Q1 drilled in wood Q, a thread 2 extending from the tip end portion to the rear end portion of the bolt body 1, a female thread portion 4 formed along the axial center portion from the rear end portion of the bolt body 1, and a square hole 3 recessed at the position of the rear end portion of the bolt body 1 for connecting an embedding tool. The construction method includes an embedding step of embedding a fixing lag screw bolt P1 shorter than a predetermined length on the bottom side of the pilot hole Q1 for embedding a lag screw bolt P of a predetermined length, and then embedding a connecting lag screw bolt P2 having a bolt insertion hole 5 in the axial center portion to form a lag screw bolt P of a predetermined length in the pilot hole Q1; and a connecting step of connecting the fixing lag screw bolt P1 by passing a fixing bolt R through the connecting lag screw bolt P2 to integrate the lag screw bolt P of a predetermined length embedded in the pilot hole Q1.

[0014] In the fixing lag screw bolt P1 of the second means, a bottomed cylindrical or cylindrical female thread portion 4 is formed inward from the rear end portion of the bolt body 1, and in the connecting lag screw bolt P2, a bolt insertion hole 5 through which the fixing bolt R is inserted is formed instead of the female thread portion 4.

[0015] In the fixing lag screw bolt P1 and the connecting lag screw bolt P2 of the third means, a female thread portion 4 is formed on the entire inner surface or a part of the inner surface of a cylindrical shape penetrating the axial center portion of the bolt body 1.

Effect of the Invention

[0016] According to the construction method of the present invention, a lag screw bolt of a predetermined length is formed in a pilot hole in which a fixing lag screw bolt and a connecting lag screw bolt are embedded, and by connecting and integrating a fixing bolt to the lag screw bolt of the predetermined length, it can be easily embedded with an ordinary embedding tool regardless of the length and diameter of the lag screw bolt.

[0017] As a result, even a large lag screw bolt can be embedded without imposing a large load on a normal embedding tool, and the embedding work can be performed even if the lag screw bolt is made larger.

[0018] In addition, by combining and embedding a fixed lag screw bolt and a connecting lag screw bolt to form a lag screw bolt of a predetermined length in a pilot hole, it becomes possible to freely select the length and diameter of the lag screw bolt to be used at the predetermined length.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0020] The present invention is mainly a lag screw bolt used when connecting cross-laminated timber (CLT). Cross-laminated timber (CLT) is timber obtained by arranging veneers (laminas) and then laminating and bonding them so that the fiber directions are orthogonal. This timber is also used for building structural materials, civil engineering materials, furniture, etc.

[0021] On the one hand, a lag screw bolt is a bolt that conventionally connects seismic hardware, also known as hold-down hardware or draw-in hardware. In construction methods such as those using cross-laminated timber (CLT) like a wood-steel hybrid structure, lag screw bolts without a hexagonal head with a female thread portion recessed at the rear end are used for various applications. The lag screw bolt P used in the present invention is this lag screw bolt without a hexagonal head, and one with a square hole 3 formed at the rear end of the bolt body 1 is used (see Fig. 1).

[0022] The construction method of the present invention is a construction method of embedding this lag screw bolt P into the pilot hole Q1, and it is a construction method of embedding a large-sized lag screw bolt P that causes a large load on the embedding tool 10 in the embedding process and the connecting process.

[0023] In the embedding process, first, a fixed lag screw bolt P1 shorter than the predetermined length is embedded on the bottom side of the pilot hole Q1 for embedding a lag screw bolt P of a predetermined length. Then, by embedding the connecting lag screw bolt P2 with its axial center penetrating on top of the fixed lag screw bolt P1, it is a process of forming a lag screw bolt P of a predetermined length in the pilot hole Q1 (see Fig. 1).

[0024] To embed the fixed lag screw bolt P1, an embedding tool 10 such as an impact wrench is connected to the square hole 3 recessed at the rear end of the bolt body 1 and embedded (see Fig. 2). Also, it is embedded using an attachment (not shown) that can be extended to the bottom side of the pilot hole Q1.

[0025] This fixed lag screw bolt P1 has a low cylindrical female thread portion 4 at the rear end (see Fig. 2). Also, this female thread portion 4 can be formed in a cylindrical shape (see Fig. 3). The fixing bolt P1 shown in Fig. 3 forms a cylindrical through hole 6 that penetrates the axial center of the bolt body 1, and a female thread portion 4 is formed above this through hole 6. The through hole 6 can achieve weight reduction of the fixed lag screw bolt P1.

[0026] The connecting lag screw bolt P2 is embedded on the fixed lag screw bolt P1 and has a bolt insertion hole 5 through which the fixing bolt R is inserted (see Fig. 4). An embedding tool 10 is connected to a square hole 3 recessed in the rear end portion of the connecting lag screw bolt P2 and sequentially embedded, and a plurality of them can be embedded (see Fig. 1). Further, the connecting lag screw bolt P2 can also form a cylindrical female thread portion 4 instead of the bolt insertion hole 5 (see Fig. 5). In this case, the fixing bolt R is inserted while being screwed into the connecting bolt P2 and connected to the fixed lag screw bolt P1.

[0027] The lengths of the fixed lag screw bolt P1 and the connecting lag screw bolt P2 are adjusted according to the size of the lag screw bolt P of a predetermined length. That is, the thicker and longer the diameter of the lag screw bolt P of a predetermined length is, the greater the load on the embedding tool 10 becomes. Therefore, the lengths of the fixed lag screw bolt P1 and the connecting bolt P2 are shortened and embedded separately so that the load on the embedding tool 10 is reduced, thereby reducing the load on the embedding tool 10.

[0028] For example, when using a simple torque wrench with a tightening torque of 200 to 500 N·m as the embedding tool 10 and continuously embedding a lag screw bolt P with a length of 600 mm and a diameter of 45 mm, the motor of the embedding tool 10 will burn out. Therefore, instead of embedding the lag screw bolt P with a length of 600 mm at once, it is divided into the fixing bolt P1 and the connecting bolt P2 and embedded, and the lag screw bolt P with a length of 600 mm is configured in the pilot hole Q1, thereby reducing the load on the embedding tool 10.

[0029] On the other hand, the connecting process is a process of connecting the fixing bolt R to the fixed lag screw bolt P1 through the connecting lag screw bolt P2 embedded in the pilot hole Q1 and integrating the lag screw bolt P of a predetermined length configured in the pilot hole Q1 (see Fig. 1). This fixing bolt R can be connected not only to the fixing bolt P1 but also by screwing it into the cylindrical female thread portion 4 formed in the connecting lag screw bolt P2 (see Fig. 5).

[0030] Furthermore, in the present invention, the structure, dimensions, material of the fixed lag screw bolt P1, the connecting lag screw bolt P2, etc., or the use of the lag screw bolt P are not limited to the illustrated examples, and can be arbitrarily changed without changing the gist of the present invention.

Explanation of Signs

[0031] P Lag screw bolt P1 Fixed lag screw bolt P2 Connecting lag screw bolt Q Wood Q1 Pilot hole R Fixed bolt S Steel plate T Connecting member 1 Bolt body 2 Thread 3 Square hole 4 Female thread part 5 Bolt insertion hole 6 Through hole 10 Embedding tool

Claims

1. A method for constructing a lag screw bolt, comprising a bolt body without a hexagonal head to be embedded in a pilot hole drilled in wood, a thread extending from the tip end portion to the rear end portion of the bolt body, a female thread portion formed along the axial center portion from the rear end portion of the bolt body, and a square hole recessed at the position of the rear end portion of the bolt body for connecting an embedding tool. The method includes an embedding step of embedding a fixing lag screw bolt shorter than a predetermined length on the bottom side of a pilot hole for embedding a lag screw bolt of a predetermined length, and then embedding a connecting lag screw bolt having a bolt insertion hole in the axial center portion to form a lag screw bolt of a predetermined length in the pilot hole; and a connecting step of connecting the fixing lag screw bolt by passing a fixing bolt through the connecting lag screw bolt to integrate the lag screw bolt of a predetermined length embedded in the pilot hole. The method for constructing a lag screw bolt is characterized by comprising the above steps.

2. The method for constructing a lag screw bolt according to claim 1, wherein the fixing lag screw bolt has a bottomed cylindrical or cylindrical female thread portion formed inward from the rear end portion of the bolt body, and the connecting lag screw bolt has a bolt insertion hole through which the fixing bolt is inserted instead of the female thread portion.

3. The method for constructing a lag screw bolt according to claim 1, wherein the fixing lag screw bolt and the connecting lag screw bolt have a female thread portion formed on the entire inner surface or a part of the inner surface of a cylindrical shape penetrating the axial center portion of the bolt body.

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