JP2025006118A - Lug screw bolt installation jig and installation method - Google Patents

Abstract

To provide a mounting jig for a lag screw bolt capable of screwing a lag screw bolt to the depth of a pilot hole drilled into wood.SOLUTION: A tightening bolt body 1 is formed so as to be connected to a female screw part L3 of a lag screw bolt L. A holding cylinder 2 is formed into which the tightening bolt body 1 is inserted and to which a head part 1B of the tightening bolt body 1 is locked. The tightening bolt body 1 is inserted into the holding cylinder 2 fitted into a pilot hole Q1. The tip of the tightening bolt body 1 is connected to the female screw part L3 of the lag screw bolt L. The tightening bolt body 1 is configured to be screwed in until the holder cylinder 2 is embedded in the pilot hole Q1.SELECTED DRAWING: Figure 3

Description

The present invention relates to an installation jig used when burying a lag screw bolt deep into wood, and an installation method using this installation jig.

Patent Document 1 describes an attachment jig that makes it easier to embed a lag screw bolt in a pilot hole in wood. This jig is equipped with a tightening bolt body 1 that connects to the female threaded portion L3 at the end of the lag screw bolt L when the lag screw bolt L without a hexagonal head is screwed into the pilot hole Q1 of wood Q to embed it, and a retaining cylinder 2 that is used to remove the tightening bolt body 1 from the end of the lag screw bolt L.

To use this mounting jig, a backing plate 3 is placed on the end of the lag screw bolt L, and the lag screw bolt L is embedded until this backing plate 3 abuts against the open end of the pilot hole Q1. After that, when removing the tightening bolt body 1 from the embedded lag screw bolt L, the tightening bolt body 1 is removed while the retaining cylinder 2 is fixed with a wrench or the like.

The lag screw bolt L without a hexagonal head is used, for example, in the method of connecting cross-laminated timber Q (CLT) described in Patent Document 2. This lag screw bolt L is formed so that the valley diameter of the thread 2 matches the inner diameter of the pilot hole Q1, and has the effect of being able to connect the cross-laminated timber Q (CLT) of a wood-steel hybrid structure to the steel material P without using any adhesive. Moreover, it is an effective part for shortening the construction period of wood-steel hybrid structures, as it eliminates the need for time-consuming tasks such as drilling the seat of the wood and filling it with epoxy resin, as is the case when using a general lag screw bolt with a hexagonal head.

Patent No. 6923984 Patent No. 6986764

The mounting jig shown in Patent Document 1 is attached to remove the tightening bolt body 1 from the tightened lag screw bolt L. As a result, this mounting jig has a limit of embedding the lag screw bolt L up to the surface position of the wood Q, which has the disadvantage of limiting the range of use of the lag screw bolt L.

On the other hand, lug screw bolts without hexagonal heads do not require drilling into the wood or filling with epoxy resin, as is the case with regular lug screw bolts, so they can also be used in new connection methods.

For example, in wood-steel hybrid structures, headless lag screw bolts can be embedded deep into pilot holes drilled into the wood, and then long connecting bolts, steel rods, and other connecting members can be attached to the lag screw bolts.

However, this type of connection method has the following issues. First, there is no means for burying the lag screw bolt deep into the drilled pilot hole. Second, there is a risk that the connecting member connected to the buried lag screw bolt will buckle inside the pilot hole, or that the connecting member will damage the area around the opening of the pilot hole.

The first issue was that lag screw bolts without hexagonal heads required a special mounting jig to be attached to the end, so they could only be buried to the surface of the wood, and could not be buried all the way to the back of a deep pilot hole. Even if a long tightening bolt was used that could be buried deep into the pilot hole, there was a risk that the long lag screw bolt would bend and deform inside the pilot hole, causing the work to be halted.

The second problem is that the connecting members used to connect to the lag screw bolts inside the pilot holes in the wood are thinner than the diameter of the pilot holes. This means that when compressive forces are applied to the connecting members due to earthquakes, etc., there is a risk that the connecting members will buckle inside the pilot holes. In addition, when the connecting members shake, there is a risk that the area around the opening of the pilot holes will be damaged.

As such, there were various issues that needed to be resolved with this new construction method, which connects lag screw bolts while they are buried deep inside the wood.

The present invention was created to solve the above problems, and aims to provide a lug screw bolt installation jig and installation method that can reliably embed a lug screw bolt deep into a pilot hole drilled into wood, prevent buckling of the connecting member connected to the lug screw bolt, and prevent damage around the opening of the pilot hole.

In order to achieve the above object, the first means of the present invention is an attachment jig for screwing a lag screw bolt L having a female threaded portion L3 at its end into a pilot hole Q1 formed in a piece of wood Q and deeper than the length of the lag screw bolt L,
A tightening bolt body 1 that connects a connecting end 1A to the female thread portion L3 of the lag screw bolt L;
a retaining cylinder 2 having one end abutting against the end of the lag screw bolt L and the other end engaging with the head 1B of the tightening bolt body 1;
A fixing head 2A is formed on the other end of the retaining cylinder 2 so as to come into contact with the surface of the pilot hole Q1.
The tip of the fastening bolt body 1 inserted into the retaining cylinder 2 is connected to the female thread portion L3 of the lag screw bolt L, and the end of the retaining cylinder 2 is abutted against the end of the lag screw bolt L,
This is an attachment jig configured so that the lag screw bolt L is screwed in with the tightening bolt body 1 until the fixed head 2A of the retaining cylinder 2 abuts against the surface side of the pilot hole Q1.

The fixing head 2A of the second means is configured to be fixed with a fixing tool when the tightening bolt body 1 is removed from the lag screw bolt L embedded in the pilot hole Q1, which has a diameter between the root diameter and the crest diameter of the thread L2 of the lag screw bolt L.

The third means is a method for attaching a lag screw bolt L having a female thread portion L3 recessed at the end thereof,
a processing step of drilling a pilot hole Q1 deeper than the length of the lag screw bolt L into the wood Q; and an embedding step of embedding the lag screw bolt L deep into the pilot hole Q1 via a retaining cylinder 2 between the head 1B of a tightening bolt body 1 connected to the female thread portion L3 and the lag screw bolt L;
a removal process of removing the fastening bolt body 1 from the embedded lag screw bolt L and extracting the retaining cylinder body 2 from the pilot hole Q1;
a reinforcing step of inserting a cylindrical reinforcing member 3 into the pilot hole Q1 from which the holding cylinder 2 has been removed;
and a connecting step of connecting a connecting member 4 to the female thread portion L3 of the lag screw bolt L through the reinforcing member 3.

In the embedding step of the fourth method, the lag screw bolt L is a hollow lag screw bolt L.

In the reinforcing step of the fifth method, the reinforcing member 3 is a reinforcing member 3 in which the lag screw bolt L having the female thread portion L3 at its end is formed into a cylindrical shape.

In the reinforcing step of the sixth method, the reinforcing member 3 is configured such that a flat polygonal fitting recess L4 is recessed in place of the female thread portion L3.

The mounting jig of the present invention eliminates the risk of work being interrupted due to bending deformation of the tightening bolt caused by the load during burying, even if a long tightening bolt is used to bury the lag screw bolt deep into the pilot hole. Therefore, the lag screw bolt can be reliably buried deep into the pilot hole. Moreover, the long tightening bolt can be easily removed from the lag screw bolt buried deep into the pilot hole.

In addition, the installation method of the present invention can prevent buckling of the connecting member connected to the lag screw bolt and damage around the opening of the pilot hole. As a result, it becomes possible to use the lag screw bolt in a new construction method.

FIG. 1 is an exploded perspective view showing an embodiment of a mounting jig according to the present invention. FIG. 4 is a partially cutaway front view showing the mounting state using the mounting jig of the present invention. 11A to 11C are diagrams showing the installation process of the installation jig of the present invention. 4(a) to 4(c) are diagrams showing the process of attaching the reinforcing member. 13A and 13B are diagrams showing the state in which the reinforcing member is attached. 11 shows another embodiment of the reinforcing member, where (a) is a bottom view of the mounting jig, (b) is a side view of the mounting jig, (c) is a plan view of the reinforcing member, and (d) is a side cross-sectional view of the reinforcing member.

The present invention is a mounting method and mounting tool for embedding a lag screw bolt L into wood Q, such as cross-laminated timber (CLT).

Cross-laminated timber (CLT) is wood made by arranging planks (laminas) and then laminating and gluing them so that the grain direction is perpendicular to the board. This type of wood is also used for building structures, civil engineering materials, furniture, etc.

On the other hand, the lag screw bolt L is a bolt that connects earthquake-resistant hardware, previously known as hold-down hardware or pull-down hardware, and is an important connecting member that ensures earthquake resistance by attaching earthquake-resistant hardware to the foundation or base and columns, or between columns or between columns and beams on upper and lower floors, in order to counter the pull-out force acting on the load-bearing walls when a wooden building is subjected to horizontal force.

In addition, lag screw bolts are important connecting materials that have advantages when constructing rigid frame structures or truss structures for joints of walls, floors, columns, beams, roofs, etc. in wooden buildings using structural laminated timber and mixed steel and wooden structures.

In new construction methods that use cross-laminated timber (CLT), such as wood-steel hybrid structures, lag screw bolts L with no hexagonal head and a female thread recessed into the end are now being used.

The mounting jig of the present invention is composed of a tightening bolt body 1 and a retaining cylinder body 2 (see Figure 1). It is used when screwing a lag screw bolt L deep into a pilot hole Q1 formed in wood Q (see Figure 2). At this time, the pilot hole Q1 is formed to be at least deeper than the length of the lag screw bolt L, and the lag screw bolt L is buried deep into this hole.

The tightening bolt body 1 has a connecting end 1A that connects to the female threaded portion L3 of the lag screw bolt L, and a head 1B that engages with the opening of the retaining cylinder 2 (see Figure 2). Then, with the lag screw bolt L screwed into the tip of the tightening bolt body 1 that has passed through the retaining cylinder 2, the lag screw bolt L is screwed deep into the pilot hole Q1.

The retaining cylinder 2 is tubular and inserted into the pilot hole Q1, with one end abutting against the end of the lag screw bolt L and the other end engaging with the head 1B of the tightening bolt body 1. In addition, a fixed head 2A is provided around the other end (see Figure 1). In the illustrated example, the fixed head 2A has a nut welded to the outer periphery of the retaining cylinder 2 (see Figure 2).

This fixing head 2A is a member that abuts against the opening of the pilot hole Q1 when the lag screw bolt L is embedded to a specified depth in the pilot hole Q1 (see Figure 2). Therefore, the length of the retaining cylinder 2 is determined by the depth to which the lag screw bolt L is embedded.

This fixed head 2A is fixed with a rotating tool such as a wrench when removing the tightening bolt body 1 from the lag screw bolt L embedded in the pilot hole Q1. In other words, when the lag screw bolt L is embedded, the connecting end 1A of the tightening bolt body 1 strongly meshes with the female thread portion L3 of the lag screw bolt L, so when the tightening bolt body 1 is rotated in the reverse direction, the retaining cylinder 2 returns with the lag screw bolt L fixed to the tightening bolt body 1. Therefore, the fixed head 2A of the retaining cylinder 2 is fixed with a rotating tool to prevent the lag screw bolt L from returning, while the tightening bolt body 1 is removed from the lag screw bolt L.

The installation method of the present invention involves embedding a lag screw bolt L deep into wood Q, such as cross-laminated timber (CLT), and connecting various connecting members 4 to the lag screw bolt L. The basic steps of the present invention include a processing step, an embedding step, a removal step, and a connecting step.

The processing step is a step of drilling a pilot hole Q1 deeper than the length of the lag screw bolt L into the wooden piece Q using a drill or the like (see FIG. 3(A)). The diameter of this pilot hole Q1 is the same as the root diameter of the thread L2 of the lag screw bolt L. The pilot hole Q1 may also be formed so as to penetrate the stacked wooden pieces Q (see FIG. 5).

The embedding process is a process of embedding the lag screw bolt L inside the pilot hole Q1 (see FIG. 3B). At this time, an installation jig consisting of a tightening bolt body 1 and a retaining cylinder 2 is used to embed the lag screw bolt L deep into the pilot hole Q1. The lag screw bolt L shown in the figure is a lag screw bolt L with a female thread at the end. It is also possible to use a lag screw bolt L formed into a cylindrical shape with a female thread at the end (see FIG. 5B). In this case, the weight of the lag screw bolt L can be reduced, making it suitable for use when using a large diameter lag screw bolt L.

In the pilot hole Q1 that penetrates the stacked pieces of wood Q, a lag screw bolt L can be embedded to connect each piece of wood Q (see FIG. 5 (a)). It is also possible to embed the lag screw bolt L in accordance with the piece of wood Q at the back of the stacked pieces of wood Q (see FIG. 5 (b)). In this way, the depth and position at which the lag screw bolt L is embedded inside the pilot hole Q1 can be set as desired.

The removal process involves removing the tightening bolt body 1 from the embedded lag screw bolt L and extracting the retaining cylinder 2 from the pilot hole Q1 (see FIG. 3(c)). To remove the tightening bolt body 1 from the lag screw bolt L, the tightening bolt body 1 is rotated in the reverse direction and removed while the fixed head 2A of the retaining cylinder 2 is fixed with a rotating tool such as a wrench. The retaining cylinder 2 is then extracted from the pilot hole Q1.

Next, the reinforcing step is a step of inserting a reinforcing member 3 into the pilot hole Q1 from which the retaining cylinder 2 has been removed (see FIG. 4). This reinforcing member 3 has a cylindrical shape that fits into the pilot hole Q1, and the shape and length of the reinforcing member 3 can be changed as desired as long as it is cylindrical enough to fit into at least the opening side of the pilot hole Q1.

The reinforcing member 3 shown in the figure is a tubular member made of a lag screw bolt with a female thread at the end (see FIG. 4). When the end of this reinforcing member 3 abuts against the embedded lag screw bolt L, the pull-out strength of the lag screw bolt L can be maximized (see FIG. (c)). It is also possible to fit this reinforcing member 3 into the opening side of the pilot hole Q1 and use it at a length that does not abut against the lag screw bolt L (not shown).

To insert this reinforcing member 3 into the pilot hole Q1, a conventional mounting jig 10 is used (see Figure 4). That is, a tightening bolt body 11, a retaining cylinder 12, and abutment plate 13 are used (see (a) of the same figure). The tightening bolt body 11 is then connected to the female threaded portion 3A at the end of the reinforcing member 3, and the reinforcing member 3 is screwed in until the abutment plate 13 abuts against the opening side of the pilot hole Q1 (see (b) of the same figure). To remove the tightening bolt body 11 from the reinforcing member 3, the retaining cylinder 12 is fixed with a fixture and removed.

In addition, the reinforcing member 3 may have a planar polygonal mating recess 3B recessed at its end instead of the female thread 3A (see FIG. 6(d)). When inserting this reinforcing member 3 into the pilot hole Q1, a mounting jig 20 is used that has a mating protrusion 21 at its end that fits into the mating recess 3B of the reinforcing member 3 (see FIG. 6(b)). In FIG. 6(a) is a bottom view of the mounting jig 20, and (c) is a plan view of the reinforcing member 3.

Furthermore, when forming a cylindrical reinforcing member 3 and inserting it into the pilot hole Q1, it is also possible to fit the reinforcing member 3 inserted into the pilot hole Q1 by hitting it with a hammer or the like (not shown). In this way, the shape and length of the reinforcing member 3 can be changed as desired.

Finally, the connecting step is a step of connecting the connecting member 4 to the female threaded portion L3 of the lag screw bolt L through the reinforcing member 3 (see FIG. 5). The connecting member 4 shown in the figure is a long connecting bolt. This connecting member 4 connects the steel plate R to the wood Q. It is also possible to use a connecting member 4 with male threads on both ends of a steel rod as the connecting member 4 (not shown), and connect other members to the lag screw bolt L via the steel rod connecting member 4. In this case, even if the side of the steel rod comes into contact with the opening side of the pilot hole Q1, the reinforcing member 3 prevents damage to the wood Q.

In addition, in the present invention, the structure, dimensions, materials, and uses of the mounting jig, reinforcing member 3, connecting member 4, and lag screw bolt L are not limited to the illustrated examples, and can be changed as desired without changing the gist of the present invention.

Q Wood Q1 Pilot hole R Steel plate L Lag screw bolt L1 Bolt body L2 Thread L3 Female thread L4 Fitting recess 1 Fastening bolt body 1A Connecting end 1B Head 2 Retaining cylinder 2A Fixed head 3 Reinforcing member 3A Female thread 3B Fitting recess 4 Connecting member 10 Mounting jig 11 Fastening bolt body 12 Retaining cylinder 13 Contact plate 20 Mounting jig 21 Fitting protrusion

Claims (6)

A mounting jig for screwing a lag screw bolt having a female threaded portion at its end into a pilot hole formed in wood that is deeper than the length of the lag screw bolt,
A tightening bolt body that connects a connecting end portion to the female thread portion of the lag screw bolt;
a retaining cylinder that is inserted into the pilot hole, one end of which abuts against the end of the lag screw bolt L, and the other end of which is engaged with the head of the tightening bolt body;
A fixing head is formed on the other end of the holding cylinder so as to come into contact with the surface of the pilot hole,
The tip of the fastening bolt body inserted into the retaining cylinder is connected to the female thread portion of the lag screw bolt, and an end of the retaining cylinder is abutted against an end of the lag screw bolt;
A mounting jig for a lag screw bolt, characterized in that the lag screw bolt is screwed in with a tightening bolt body until the fixed head of the retaining cylinder abuts against the surface side of the pilot hole. The mounting jig for a lag screw bolt according to claim 1, wherein the fixing head is configured to be fixed with a fixing tool when the tightening bolt body is removed from the lag screw bolt embedded in the pilot hole having a diameter between the root diameter and the crest diameter of the thread of the lag screw bolt. A method for installing a lag screw bolt having a female thread recessed at an end thereof, comprising the steps of:
A processing step of drilling a pilot hole deeper than the length of the lag screw bolt into the wood;
an embedding step of embedding the lag screw bolt deep into a pilot hole via a retaining cylinder between a head of a tightening bolt body connected to the female threaded portion and an end of the lag screw bolt;
a removal process of removing the tightening bolt body from the embedded lag screw bolt and extracting the retaining cylinder body from the pilot hole;
a reinforcing step of inserting a cylindrical reinforcing member into the pilot hole from which the holding cylinder was removed;
a connecting step of connecting a connecting member to the female threaded portion of the lag screw bolt through the reinforcing member. The method for installing a lag screw bolt according to claim 3, wherein the lag screw bolt is a hollow lag screw bolt in the embedding step. The method for installing a lag screw bolt according to claim 4, wherein in the reinforcing step, the reinforcing member is a tubular reinforcing member formed from the lag screw bolt having the female threaded portion at its end. 5. The method for attaching a lag screw bolt according to claim 4, wherein in the reinforcing step, the reinforcing member is configured to have a fitting recess having a planar polygonal shape recessed therein instead of the female thread portion.