JP2023170319A - Lag screw bolt and method for burying the same into wood material - Google Patents

Abstract

To provide a lag screw bolt capable of efficiently carrying out an operation to inject an adhesive; and to provide a method for burying the lag screw bolt into a wood material, which allows the lag screw bolt to firmly couple with the wood material by increasing an injection amount of the adhesive.SOLUTION: Narrow guide surfaces 4, which are surfaces guided by tip holes pre-drilled in a wood material, are disposed on both sides of a base part of a male screw 3 of a lag screw part 2, a groove 5 recessed from the guide surfaces 4 is formed between the guide surfaces 4 adjacent to each other in an axial direction, a spiral groove 6 is disposed in the axial direction of the lag screw part, and a groove 7 extending in the axial direction is formed in the lag screw part 2. A communication hole communicating with the tip hole pre-drilled in the wood material is disposed from a spiral space or an axial space to an outer surface of the wood material, a liquid adhesive is injected into the spiral space and the axial space through the communication hole, and the lag screw part and the wood material are coupled with each other via the adhesive.SELECTED DRAWING: Figure 3

Description

The present invention relates to a lag screw bolt and an embedding method for screwing and embedding the lag screw bolt into a wood material.

A lag screw bolt is a joint that has a male thread around the shaft (lag screw) and a female or male thread at the end. A tip hole with approximately the same diameter as the root diameter of the lag screw bolt is made in advance in the wood, and the lag screw bolt is screwed into the tip hole using a special tool and buried. The wood in which the lag screw bolt is embedded is joined to other members by fastening another connector to the female or male thread provided at the end.

When screwing a lag screw bolt into wood and burying it, the tip hole drilled in the wood and the root diameter of the lag screw bolt are almost the same diameter, so as it is screwed in, the contact area between the tip hole and the trough increases, and gradually It is necessary to screw it in with great force. Therefore, a special tool with strong torque is required. On-site work requires a lot of effort and time.
Further, the axial bonding force between the lag screw bolt and the wood in which the lag screw bolt is embedded in this manner cannot be said to be very large because the tensile force is supported only by the male threaded portion.

In order to solve this problem, the present inventor developed a lag screw bolt that can be easily screwed into wood, and a lag screw bolt that can be firmly connected to wood. discloses a method for embedding in wood material (Patent Document 1).
Such a lag screw bolt is provided with narrow guide surfaces on both sides of the base of the male thread of the lag screw part, and a groove recessed from the guide surface is formed between the axially adjacent guide surfaces. A spiral groove is provided that extends spirally in the axial direction of the part.
In addition, a method for embedding a lag screw bolt into a wood material that can be firmly bonded to the wood material is to bury the lag screw bolt in the wood material by forming it between the tip hole drilled in advance in the wood material and the helical groove of the buried lag screw bolt. A communication hole communicating from the spiral space to the outer surface of the wood material is provided, and a liquid adhesive is injected into the spiral space through the communication hole to bond the lag screw portion and the wood material via the adhesive. It is something.

According to such a lag screw bolt, the lag screw bolt can be screwed in while the guide surface is guided by the tip hole drilled in advance in the wooden material. In addition, since the spiral groove is recessed from the guide surface and does not come into contact with the circumferential surface of the tip hole, frictional resistance is reduced, making it possible to screw the lag screw bolt into the tip hole drilled in wood material with less force. can do well.
In addition, according to the above method of embedding a lag screw bolt in a wood material, in which the lag screw bolt is embedded in the wood material and fixed, the adhesive injected into the spiral space strengthens the lag screw part and the wood material. can be combined with Therefore, even if a strong tensile force is applied during an earthquake or the like, it has sufficient strength.

However, since the spiral groove portion into which the adhesive is injected is a groove extending in a spiral shape, it takes time to complete the injection of the adhesive. Therefore, it cannot be said that the work efficiency is high. Further, since the only part of the adhesive bonded with adhesive is the spiral groove, the amount of adhesive injected cannot be said to be that large.

JP2020-200843A

Therefore, the present invention provides a lag screw bolt that enables efficient adhesive injection work, and also enables the lag screw bolt to be firmly bonded to a wooden material by increasing the amount of adhesive injected. The object of the present invention is to provide a method for embedding a lag screw bolt in a wooden material.

In order to solve the above problem, the lag screw bolt according to claim 1 has narrow guide surfaces on both sides of the base of the male screw of the lag screw portion, which are the surfaces to be guided to the tip hole pre-drilled in the wood material. A groove is formed between the axially adjacent guide surfaces to form a groove recessed from the guide surface to provide a helical groove extending spirally in the axial direction of the lag screw portion. It is characterized by forming an extending groove.
In the invention according to claim 2, a plurality of grooves extending in the axial direction are formed in the lag screw portion at equal intervals in the circumferential direction.
The invention according to claim 3 is a method for embedding a lag screw bolt in a wooden material for embedding and fixing the lag screw bolt according to claim 1 or 2 in a wooden material, wherein a tip hole is pre-drilled in the wooden material. A communication hole is provided that communicates with the outer surface of the wooden material from the helical space or axial space formed between the helical groove or the axially extending groove of the buried lag screw bolt, and the liquid is passed through the communication hole. The method is characterized in that an adhesive is injected into the helical space and the axial space, a plug is driven into the communication hole, and the lag screw portion and the wood material are bonded via the adhesive.
In the invention according to claim 4, communicating holes communicating with the outer surface of the wooden material are provided at the leading end and the rear end of the spiral space or the axial space, respectively.

According to the invention according to claim 1, since the groove extending in the axial direction is formed in the lag screw portion, the adhesive can be injected through the groove extending in the axial direction in addition to the helical groove extending in a spiral shape. Therefore, the injection work can be completed in a short time, and the adhesive injection work can be performed efficiently.
According to the invention according to claim 2, since a plurality of grooves extending in the axial direction are formed in the lag screw portion at equal intervals in the circumferential direction, it is possible to further shorten the adhesive injection time. Furthermore, since more adhesive can be injected, the adhesive strength can be further increased.
According to the invention according to claim 3, the wood is removed from the helical space or axial space formed between the pre-drilled hole in the wood and the helical groove or axially extending groove of the buried lag screw bolt. A communicating hole is provided on the outer surface of the material, liquid adhesive is injected into the spiral space and the axial space through the communicating hole, a plug is driven into the communicating hole, and the lag screw part and the wood material are bonded. Since they are bonded through an adhesive, the adhesive can be injected not only through the spiral space but also through the axial space, making it possible to complete the injection work in a short time and making the adhesive injection work more efficient. . Furthermore, the adhesive injected not only into the spiral space but also into the axial space allows the lag screw portion and the wood material to be firmly bonded. Therefore, even if a strong tensile force is applied during an earthquake or the like, it has sufficient strength.
According to the invention according to claim 4, communication holes communicating with the outer surface of the wooden material are provided at the leading end and the rear end of the spiral space or the axial space, respectively, so that the spiral space and the axial space are connected to each other. Adhesive can be injected over the entire area from the tip to the rear end. Therefore, the entire area of the love screw portion in the axial direction can be bonded with the adhesive, and the lag screw bolt and the wood material can be firmly bonded.

FIG. 3 is a front view of a lag screw bolt according to an example. 2 is an enlarged plan view of FIG. 1. FIG. FIG. 2 is an enlarged view of the main part of FIG. 1. FIG. FIG. 4 is a cross-sectional view taken along the line AA in FIG. 3. 4 is a sectional view taken along line BB in FIG. 3. FIG. It is an explanatory view showing how a lag screw bolt is buried in a wooden material. FIG. 3 is a sectional view of a main part of the lag screw bolt in an embedded state according to the embodiment. 8 is a sectional view taken along line CC in FIG. 7. FIG. FIG. 9 is a sectional view corresponding to FIG. 8 after the adhesive is injected. FIG. 9 is a cross-sectional view corresponding to FIG. 9 of a portion without grooves in the axial direction after adhesive injection.

Embodiments of the present invention will be specifically described below based on the drawings. The lag screw bolt 1 according to the embodiment of the present invention has narrow guide surfaces 4, 4 provided in the valley of the lag screw portion (shaft portion) 2 on both sides of the base of the male thread 3 in the axial direction, and are adjacent to each other in the axial direction. A groove 5 recessed in the axial direction from the guide surfaces 4 is formed between the guide surfaces 4, and a helical groove 6 extending spirally in the axial direction of the lag screw portion 2 is provided.

Further, the lag screw portion 2 is formed with a groove 7 extending in the axial direction over the entire area from the tip to the rear end. Four grooves 7 extending in the axial direction are formed at equal intervals (every 90 degrees) in the circumferential direction of the lag screw bolt (FIG. 5).
In addition, although FIG. 5 shows a groove 7 formed with four grooves extending in the axial direction, two grooves are formed at equal intervals (180°) in the circumferential direction, and three grooves are formed at equal intervals (every 120°) in the circumferential direction. You may also do so. It is preferable to set the distances at equal intervals, since this provides balance in the circumferential direction.

The groove 7 extending in the axial direction serves as a flow path for the adhesive. In the case of only the spiral groove 6, the injected adhesive flows spirally along the helical groove, so it takes time to complete the injection, but by providing the groove 7 extending in the axial direction, the injected adhesive flows in a spiral manner. Since the adhesive flows in the axial direction along the groove 7, the injection time for the adhesive can be significantly shortened. Furthermore, after the injection is completed, it contributes to increasing the adhesive strength.

By forming a plurality of grooves 7 extending in the axial direction at equal intervals in the circumferential direction, the adhesive injection work can be completed in a shorter time than in the case of only a single groove. Furthermore, after the injection is completed, more adhesive can be filled than in the case of a single strip, which contributes to further increasing the adhesive strength.

The narrow guide surface 4 has a diameter corresponding to the diameter of the tip hole 9 formed in the wooden material 8. This narrow guide surface 4 is a surface that is guided to a tip hole 9 pre-drilled in the wood material 8. When screwing the lag screw bolt 1 into the tip hole 9, the guide surface 4 is guided to the tip hole 9. It is guided and screwed in.

In the lag screw bolt 1 according to the embodiment shown in FIGS. 1 and 3, the cross-sectional shape of the helical groove 6 is formed into a concave arc shape. By forming the cross-sectional shape of the helical groove 6 into a concave arc shape in this way, the liquid adhesive can easily flow into the helical groove 6, and the adhesive can be uniformly filled into the helical groove 6.

The dimensions of the lag screw bolt 1 in FIGS. 1 and 3 are as follows: outer diameter φ ₁ is 38 mm, guide surface 4 diameter φ ₂ is 32 mm, guide surface 4 width W ₁ is 1 mm, and the diameter of the bottom of the spiral groove 6 is φ ₃ is 26 mm, the pitch of the male screw 3 is 10 mm, the total length L ₁ is 650 mm, and the length L ₂ of the lag screw portion is 580 mm. The width W ₂ of the groove 7 extending in the axial direction is 5 mm, and the depth h of the groove 7 is 5.5 mm. Note that the dimensions shown here are just examples and can be changed as appropriate.

The width W ₁ of the guide surface 4 is preferably about 1/20 to 1/5 of the pitch of the male thread 3. If it is less than 1/20, the width of the guide surface is too narrow and the guiding function cannot be fully demonstrated. On the other hand, if it exceeds 1/5, the width of the guide surface is too wide and the frictional resistance when screwing into the tip hole is large, reducing the efficiency of the screwing operation.

The width W ₂ of the groove 7 extending in the axial direction is preferably about 1/10 to 3/10 of the outer diameter φ ₁ . If it is less than 1/10, it is not possible to ensure a sufficient amount of adhesive that can be injected into the groove 7 extending in the axial direction, so that the effect of increasing adhesive strength is small. On the other hand, if it exceeds 3/10, the area of the guide surface 4 becomes too small and the guiding function becomes insufficient, which may cause problems in screwing work.
The width W ₂ of the groove 7 is preferably wide within the above range. Although the width W ₂ of the groove 7 extending in the axial direction is illustrated as 5 mm, it may be approximately 10 mm. When the width W ₂ of the groove 7 is increased to about 10 mm, the area of the guide surface 4 becomes correspondingly narrower. Therefore, the frictional resistance when screwing the lag screw bolt 1 into the tip hole 9 previously drilled in the wood material 8 is reduced, contributing to increasing the efficiency of the screwing operation. Furthermore, since more adhesive can be filled, it also contributes to increasing adhesive strength.

A female threaded portion 10 is provided at the base end of the lag screw bolt 1, as in the conventional product. Note that a male threaded portion may be provided at the base end depending on the purpose.

In the embodiments shown in FIGS. 1 and 3, the helical groove 6 has a concave arc cross-sectional shape, but it may also be concave (not shown). Note that the cross-sectional shape of the spiral groove 6 is not limited to the concave arc shape or concave shape.

Next, the work of embedding the lag screw bolt 1 in the wooden material 8 according to the embodiment will be explained with reference to FIG. First, a tip hole 9 is made in the wooden material 8 as in the conventional method. The diameter of the tip hole 9 is approximately the same as the diameter φ ₂ of the guide surface 4. Further, a wooden material 8 is inserted from the helical groove 6 or the axially extending groove 7 at a position corresponding to the tip and rear end of the helical groove 6 or the axially extending groove 7 when the lag screw bolt 1 is buried. Communication holes 11, 11 communicating with the outer surface are opened. Note that a communication hole communicating with the outer surface of the wooden material 7 may be additionally provided at a position corresponding to the axially intermediate portion of the helical groove 6 or the axially extending groove 7.

Next, the lag screw bolt 1 is screwed into the tip hole 9 previously drilled in the wooden material 8 in the same manner as in the conventional method. At this time, the contact portion between the peripheral surface of the tip hole 9 and the lag screw bolt 1 is only the narrow guide surface 4, and the helical groove portion 6 is not in contact. In this way, since the contact area between the tip hole 9 and the lag screw bolt 1 is small, the frictional resistance is small, and compared to conventional screwing operations, the screwing operation can be carried out more efficiently in a shorter time and with less force. .

In this way, when the lag screw bolt 1 is buried in the wooden material 8 (FIG. 6(b)), the tip hole 9 previously drilled in the wooden material 8 and the helical groove 6 of the buried lag screw bolt 1 are connected. A spiral space 12 is formed therebetween, and an axial space 13 is also formed between the tip hole 9 and the axially extending groove 7 (FIGS. 7 and 8). These spiral spaces 12 and axial spaces 13 are in communication. Communication holes 11, 11 communicating with the outer surface of the wooden material 8 are provided at the tip and rear ends of the spiral space 12 or the axial space 13.

Next, liquid adhesive is injected into the spiral space 12 and the axial space 13 through the communication hole 11 using an injection gun 14 or the like. When the injection (filling) is completed, plugs 15, 15 are driven into the communication hole 11 and fixed. In this way, the wooden material 8 and the lag screw bolt 1 are not only connected by the conventional male screw part 3, but also the lag screw part 2 and the wooden material 8 are firmly connected through the adhesive 16. (Figures 9 and 10). Therefore, it has a large proof strength against tensile stress.

Here, communicating holes 11, 11 are provided in the parts of the wooden material 8 corresponding to the tip and rear ends of the spiral space 12 or the axial space 13, respectively, and communicate with the outer surface of the wooden material 8. The adhesive can be injected and filled over the entire area from the tip to the rear end of the shaped space 12 and the axial space 13. Therefore, the entire area of the love screw portion 2 in the axial direction can be bonded with the adhesive 16, and the lag screw bolt 1 and the wood material 8 can be firmly connected.
By injecting and filling the axial space 13 with adhesive in addition to the conventional spiral space 12, it is possible to bond with more adhesive 16 and increase the adhesive strength.

Although FIG. 6 shows an example in which one lag screw bolt (1) is buried in the wooden material 8, multiple lag screw bolts may be buried depending on the dimensions of the wooden material, the dimensions of the lag screw bolt, etc. You can also do this.
Note that typical examples of the wooden material 8 include pillar materials and beam materials.

1 Lag screw bolt 2 Lag screw part 3 Male thread 4 Guide surface 5 Groove 6 Spiral groove 7 Groove extending in the axial direction 8 Wood material 9 Tip hole 10 Female thread part 11 Communication hole 12 Spiral space 13 Axial space 14 Injection gun 15 Plug 16 Adhesive φ ₁ Outer diameter φ ₂ Diameter of the guide surface φ ₃ Diameter of the bottom of the spiral groove W ₁ Width of the guide surface W ₂ Width of the axial groove h Depth of the axial groove

Claims (4)

Narrow guide surfaces are provided on both sides of the base of the male thread of the lag screw part to be guided into the tip hole pre-drilled in the wood material, and a narrow guide surface is provided between the guide surfaces adjacent in the axial direction. A lag screw bolt characterized in that a recessed groove is formed to provide a spiral groove extending spirally in the axial direction of the lag screw part, and a groove extending in the axial direction is formed in the lag screw part. The lag screw bolt according to claim 1, wherein a plurality of grooves extending in the axial direction are formed in the lag screw portion at equal intervals in the circumferential direction. 3. A method for embedding a lag screw bolt in a wooden material according to claim 1 or 2, wherein the lag screw bolt is embedded in a wooden material and fixed, the lag screw bolt being embedded in the wood material in a spiral manner. A communication hole is provided that communicates with the outer surface of the wooden material from the spiral space or axial space formed between the groove or the axially extending groove, and the liquid adhesive is applied to the spiral space and the axial space through the communication hole. A method for embedding a lag screw bolt in a wood material, characterized by injecting the bolt into the space in the axial direction, driving a plug into the communication hole, and joining the lag screw part and the wood material via an adhesive. 4. The method of embedding a lag screw bolt in a wooden material according to claim 3, wherein communication holes communicating with the outer surface of the wooden material are provided at the leading end and the rear end of the spiral space or the axial space, respectively.

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