JP7701726B2 - Screw-in anchor - Google Patents

Description

The present invention relates to anchors that are fixed to various types of frameworks, such as concrete buildings and structures, and in particular to screw-in anchors that are screwed into mounting holes formed in the framework.

When hanging objects such as air conditioners, lighting fixtures, and various pipes in an existing ceiling structure such as a concrete building, an anchor is attached to the structure to support the hanging object. Conventionally, as this type of anchor, a screw-in type anchor is known in which a mounting hole (prepared hole) for mounting the anchor is formed on the surface of the structure, and the anchor is screwed into the mounting hole to fix it (for example, Patent Documents 1, 2, and 3).

These conventional screw-in anchors have a shaft with a specified diameter and a male screw formed at the tip, which can be fixed to the structure by screwing the male screw into a mounting hole formed in the structure. In addition, conventional screw-in anchors have a structure in which the other end of the shaft protrudes from the surface of the structure, allowing a workpiece such as a suspended object to be attached to the shaft.

JP 2004-19370 A JP 2019-78405 A JP 2020-2565 A

However, the drilling work to form mounting holes in the surface of the structure becomes more difficult as the hole diameter becomes larger. For example, as the hole diameter becomes larger, the bit diameter of the drill bit becomes larger, and a large force is required to press a power tool such as a hammer drill or hammer drill against the structure, making the drilling work difficult. In particular, if an attempt is made to form a mounting hole perpendicular to the ceiling part of the structure, the drilling work will be done at a high place, which is a problem of poor work efficiency. In addition, as the hole diameter becomes larger, a large amount of concrete cutting chips will be generated and fall from the hole during drilling, which further reduces work efficiency. In order to solve these problems, it is necessary to reduce the diameter of the mounting hole.

For example, FIG. 12 is a diagram showing an example of a conventional screw-in anchor 200. In this screw-in anchor 200, a first male screw portion 201 is formed at the tip side of a shaft portion having a predetermined diameter (for example, about φ9 to 10 mm), and a second male screw portion 202 is formed at the rear end side of the shaft portion. Meanwhile, a mounting hole 102 having a diameter equal to or slightly larger than the diameter of the shaft portion of the screw-in anchor 200 is formed on the underside 101 of the body 100. As shown in FIG. 12(a), the screw-in anchor 200 is fixed to the body 100 by screwing the first male screw portion 201 formed at the tip side of the shaft portion into the mounting hole 102. In addition, when the screw-in anchor 200 is fixed to the body 100, the second male screw portion 202 formed at the rear end side of the shaft portion is in a state of protruding from the underside 101 of the body 100. The screw-in anchor 200 supports the work 30 that supports the suspended object by attaching it to the second male screw portion 202 that protrudes from the underside 101 of the body 100, and tightening the nut 31.

In the above configuration, if the diameter of the mounting hole 102 is reduced to, for example, φ5 to 6 mm, the diameter of the shaft of the screw-in anchor 200 screwed into the mounting hole 102 is also reduced to, for example, φ5 to 5.5 mm, and the shear strength of the shaft is reduced. For example, when a large force F (see FIG. 12(a)) acts laterally on the workpiece 30 during an earthquake, the force F acts as a shear stress that shears the shaft at the boundary surface between the workpiece 30 and the underside 101 of the structure 100. The shear stress is inversely proportional to the cross-sectional area of the shaft. Therefore, the smaller the diameter of the shaft, the greater the shear stress acting on the shaft. Therefore, if the diameter of the shaft of the screw-in anchor 200 is reduced in conjunction with the reduction in the diameter of the mounting hole 102, the shaft of the screw-in anchor 200 may be sheared during an earthquake, causing the workpiece 30 to fall from the ceiling, as shown in FIG. 12(b).

Therefore, the conventional screw-in anchor 200 is not permitted to have a small diameter shaft, nor is it permitted to reduce the diameter of the mounting hole 102 into which the screw-in anchor 200 is attached. Due to these circumstances, it has not been possible to reduce the diameter of the mounting hole 102 formed in the underside 101 of the structure 100 in the past, and drilling work cannot be performed efficiently. As a result, there is a problem in that the work of attaching the screw-in anchor to the structure cannot be performed efficiently.

The present invention was made to solve the above-mentioned problems of the conventional method, and aims to provide a screw-type anchor whose shaft will not shear when an earthquake occurs, and which can be attached to a building frame more efficiently than conventional methods.

In order to achieve the above object, firstly, the present invention provides a screw-type anchor that is fixed to a skeleton by being screwed into an attachment hole having a first hole formed in a surface of the skeleton and a second hole formed at a rear end of the first hole and having a smaller diameter than the first hole, the anchor having a shaft portion that is inserted into the attachment hole, the shaft portion having a first shaft portion with a smaller diameter that is provided on a tip side and capable of being inserted into the second hole, and a second shaft portion with a larger diameter than the first shaft portion that is provided on a rear end side of the first shaft portion and capable of being inserted into the first hole but not capable of being inserted into the second hole. The outer peripheral surface of the first shaft portion is formed with a first male screw portion that is screwed into the inner peripheral wall of the second hole, and when the first male screw portion is screwed into the inner peripheral wall of the second hole and the shaft portion is fixed to the mounting hole, the second shaft portion protrudes from the inside of the mounting hole to the outside of the body surface, and a second male screw portion to which a nut can be attached is formed on the outer peripheral surface of the second shaft portion that protrudes to the outside of the body surface, and the second male screw portion has a larger diameter than the first male screw portion .

Secondly, the present invention is characterized in that in the screw-in anchor having the above-mentioned first configuration, the second shank is arranged with its tip abutting against the inner end of the first hole.

Thirdly, the present invention is characterized in that in the screw-in anchor having the first or second configuration described above, the second shank is arranged in such a manner that the outer periphery of the portion embedded in the first hole is in close proximity to the inner periphery wall of the first hole.

Fourthly , the present invention is a screw-type anchor having any one of the first to third configurations, characterized in that a long nut is attached to the second male thread portion , and a bolt can be attached to the long nut.

Fifth , the present invention is a screw-in anchor having any of the first to fourth configurations described above, characterized in that the second shank is provided with an engagement portion at a rear end of the second male thread portion , to which a tool for applying a rotational torque to the second shank can be attached and detached.

The present invention provides a screw-type anchor whose shaft will not shear during an earthquake and which can be attached to a building frame more efficiently than conventional anchors.

FIG. 1 is a perspective view of a screw-in anchor. FIG. 2 is a side view of a threaded anchor. FIG. 13 illustrates a mounting hole into which a threaded anchor is installed. FIG. 1 illustrates a drill bit capable of forming a first hole and a second hole in a single drilling operation. 13A to 13C are diagrams showing a procedure for drilling mounting holes in a body. 13A to 13C are diagrams showing a procedure for attaching a screw-in anchor to a mounting hole. 13A to 13C are diagrams showing a procedure for attaching a screw-in anchor to a mounting hole. 13A to 13C are diagrams showing a procedure for attaching a screw-in anchor to a mounting hole. FIG. 13 is a diagram showing an example of attaching a workpiece to a mounting portion of a screw-in anchor fixed to a building structure. FIG. 13 is a diagram showing an example of a configuration in which a bolt can be attached to the mounting portion of a screw-in anchor. 13A and 13B are diagrams showing modified examples of the engagement portion. FIG. 1 is a diagram showing an example of a conventional screw-type anchor.

Below, preferred embodiments of the present invention will be described in detail with reference to the drawings. Note that in the drawings referred to below, common members are given the same reference numerals, and redundant descriptions of those members will be omitted.

Figure 1 is a perspective view showing a screw-in anchor 1 according to one embodiment of the present invention. Figure 2 is a side view of the screw-in anchor 1. The screw-in anchor 1 is an anchor that is screwed into various frameworks such as concrete buildings and structures, and is particularly suitable for attachment to ceiling frameworks such as ceiling structures. The screw-in anchor 1 has a shaft 10 made of a metal rod-shaped member. The shaft 10 has a first shaft 11 provided at the tip side and a second shaft 12 provided at the rear end side of the first shaft 11. The first shaft 11 is provided in approximately half of the tip side of the shaft 10 (the upper end side in Figures 1 and 2), and the second shaft 12 is provided in approximately half of the rear end side of the shaft 10 (the lower end side in Figures 1 and 2).

The first shaft portion 11 has a first diameter (for example, about φ5 to 5.5 mm), and a first male screw portion 13 is formed on its outer circumferential surface. The first male screw portion 13 is formed as a tapping screw for fixing the screw-type anchor 1 to the body by being screwed into an attachment hole 110 (see FIG. 3) formed in the body 100. For example, the first male screw portion 13 is formed as a double helix structure with a large-diameter first screw thread 13a and a small-diameter second screw thread 13b. However, the helical structure of the first male screw portion 13 may be formed only with the large-diameter first screw thread 13a. With such a helical structure, the first male screw portion 13 can advance the first shaft portion 11 into the attachment hole 110 formed in the body 100. This first shaft portion 11 is formed with a smaller diameter than the second shaft portion 12.

The second shaft portion 12 is coaxial with the first shaft portion 11, has a second diameter (for example, about φ9 to φ10 mm) that is about twice as large as the first diameter, and has an attachment portion 14 on the outer circumferential surface of the rear end side to which a nut can be attached. The second shaft portion 12 has a larger diameter than the first shaft portion 11. Therefore, a step portion 19 is formed at the tip of the second shaft portion 12 to which the rear end of the first shaft portion 11 is connected. The attachment portion 14 has a second male screw portion 15 formed on the outer circumferential surface of the second shaft portion 12. The second male screw portion 15 is formed as a metric screw. This second male screw portion 15 is formed from a position a predetermined distance away from the step portion 19 toward the rear end side of the second shaft portion 12. Therefore, the second shaft portion 12 has a screwless portion 16 in the vicinity of the step portion 19 (specifically, the area from the step portion 19 to a predetermined distance).

The second shaft portion 12 is provided with an engagement portion 17 at the rear end of the mounting portion 14 to which a tool for applying a rotational torque to the second shaft portion 12 can be attached and detached. For example, the engagement portion 17 is formed as a hexagonal protrusion 18 protruding from the rear end surface of the mounting portion 14. The axis of the protrusion 18 is the same as the axis of the first shaft portion 11 and the second shaft portion 12. The shape of the protrusion 18 is not necessarily limited to a hexagonal shape, and may be a square shape. The outer diameter of the protrusion 18 is smaller than the outer diameter of the second shaft portion 12. Therefore, when the nut is attached to the second male screw portion 15, the nut does not interfere with the protrusion 18.

Figure 3 is a diagram illustrating an example of a mounting hole 110 in which the screw-in anchor 1 is installed. The mounting hole 110 shown in Figure 3 is formed on the underside 101 of the body 100 in which the screw-in anchor 1 is installed. The mounting hole 110 is composed of a first hole 111 formed on the surface (underside 101) of the body 100 and a second hole 112 formed at the inner end of the first hole 111. The second hole 112 is coaxial with the first hole 111 and has a smaller diameter than the first hole 111. The diameter D1 of the first hole 111 is the same diameter as or slightly larger than the diameter of the second shaft portion 12 of the screw-in anchor 1. The diameter D2 of the second hole 112 is the same diameter as or slightly larger than the diameter of the first shaft portion 11 of the screw-in anchor 1 and is smaller than the outer diameter of the first thread 13a formed on the first shaft portion 11. The depth H1 of the first hole 111 is formed to be approximately the same dimension as the height T2 of the unscrewed portion 16 provided in the second shank 12 of the screw-in anchor 1. However, the height T2 of the unscrewed portion 16 may be formed to be lower than the depth H1 of the first hole 111. Furthermore, the depth H2 of the second hole 112 is formed to be deeper than the depth H1 of the first hole 111 and deeper than the height T1 of the first shank 11 of the screw-in anchor 1.

The mounting hole 110 in which the screw-in anchor 1 is installed has a two-stage structure of the first hole 111 and the second hole 112 as described above. For example, the mounting hole 110 may be formed by first forming a small-diameter second hole 112 on the underside 101 of the body 100, and then forming the first hole 111 by countersinking the periphery of the second hole 112. However, in this case, it is necessary to use two drill bits of different diameters to form the mounting hole 110 in the body 100. That is, it is necessary to first attach a small-diameter drill bit to a power tool such as a hammer drill or a hammer drill to form the second hole 112, and then replace it with a large-diameter drill bit to form the first hole 111. In this case, when forming the second hole 112, the drilling work can be performed using a small-diameter drill bit, so that the force pressing the power tool against the body 100 can be reduced, and the drilling work can be performed smoothly. In addition, since the depth H1 of the first hole 111 formed on the front side of the second hole 112 using a large-diameter drill bit is relatively shallow, the force pressing the power tool against the body 100 is not large, and the drilling operation can be performed smoothly. However, in this case, the drill bit needs to be replaced during the drilling operation, so the work efficiency cannot be significantly improved. Therefore, it is preferable to use a drill bit as shown below.

Figure 4 is a diagram showing a drill bit 20 that can form a first hole 111 and a second hole 112 in a single drilling operation. This drill bit 20 has a drill blade 21 that forms the first hole 111 in the body 100, an expansion blade 22 provided at the rear end of the drill blade 21, and a hexagonal mounting portion 23 for mounting the drill bit 20 to a chuck portion of a power tool. The drill blade 21 is provided at the tip of the drill bit 20, and the mounting portion 23 is provided at the rear end of the drill bit 20. The expansion blade 22 is provided between the drill blade 21 and the mounting portion 23, and is formed in a wing shape that protrudes outward from the outer circumferential surface of the drill bit 20. This expansion blade 22 forms a second hole 112 near the lower surface 101 of the body 100.

The diameter D2 of the drill bit 21 is approximately equal to the diameter D2 of the second hole 112 of the mounting hole 110 formed in the body 100. The diameter D1 of the expansion blade 22 is approximately equal to the diameter of the first hole 111 of the mounting hole 110 formed in the body 100. The length L2 of the drill bit 21 is approximately equal to the depth H2 of the second hole 112 of the mounting hole 110 formed in the body 100. The length L1 of the expansion blade 22 is approximately equal to the depth H1 of the first hole 111 of the mounting hole 110 formed in the body 100, for example. However, the length L1 of the expansion blade 22 may be shorter than the depth H1 of the first hole 111.

5 is a diagram showing the procedure for drilling the mounting hole 110 in the body 100 using the drill bit 20. First, as shown in FIG. 5(a), the drill bit 20 is attached to the chuck portion 29 of the power tool 28, the tip of the drill bit 21 is pressed against the position where the mounting hole 110 is to be formed on the underside 101 of the body 100, and the power tool 28 is operated to form the second hole 112 in the body 100. The diameter D2 of the drill bit 21 is smaller than the diameter of the drill bit that forms the mounting hole for screwing in a conventional screw-in anchor. Therefore, when forming the second hole 112 in the body 100, the force pressing the power tool 28 against the body 100 can be reduced, and the drilling operation can be performed smoothly. After that, when the expansion blade 22 hits the bottom surface 101 of the body 100, as shown in FIG. 5(b), the expansion blade 22 scrapes off the peripheral portion of the second hole 112, forming a large-diameter first hole 111 below the second hole 112. At this time, the force pressing the power tool 28 against the body 100 does not become too large, so the drilling operation can be continued smoothly. In addition, since the force pressing the power tool 28 against the body 100 can be reduced, the fatigue level of the operator can also be reduced. Then, when the rear end of the expansion blade 22 advances to the position of the bottom surface 101 of the body 100, the drilling operation of the mounting hole 110 is completed.

In this way, by using the drill bit 20 shown in FIG. 4, it is possible to form the mounting hole 110, which is a two-stage structure consisting of a first hole 111 and a second hole 112, in a single drilling operation. In other words, the mounting hole 110 can be formed in one drilling operation without changing the drill bit, improving work efficiency. Then, once the mounting hole 110 is formed in the underside 101 of the body 100, the screw-type anchor 1 is attached to the mounting hole 110.

6 to 8 are diagrams showing the procedure for attaching the screw-in anchor 1 to the attachment hole 110. As shown in FIG. 6, when the screw-in anchor 1 is attached to the attachment hole 110, a socket bit 27 with a hexagonal hole is attached to the engagement portion 17 provided at the rear end of the second shaft portion 12. The rear end of the socket bit 27 is attached to the chuck portion of the power tool. Then, the first shaft portion 11 is inserted into the attachment hole 110, and the power tool is operated with the tip of the first shaft portion 11 abutting the periphery of the second hole 112, and the socket bit 27 is rotated in a predetermined rotation direction R. At this time, the operator can push the power tool upward to screw the first shaft portion 11 into the second hole 112 while causing the first male screw portion 13 formed on the first shaft portion 11 to bite into the inner wall of the second hole 112, as shown in FIG. 7. At this time, the first shaft 11 is screwed into the small-diameter second hole 112, so the force required by the operator to press the power tool upward can be reduced. This allows the first shaft 11 to be screwed into the second hole 112 smoothly. In addition, the force required to press the power tool upward can be reduced, which can reduce the operator's fatigue.

As the first shank 11 is screwed into the second hole 112, the second shank 12 enters the first hole 111. Then, as shown in FIG. 8, when the step portion 19 at the tip of the second shank 12 abuts against the inner end of the first hole 111, installation of the screw-type anchor 1 in the structure 100 is completed. At this time, the entire first male screw portion 13 formed in the first shank 11 is screwed into the second hole 112. For example, even if the second hole 112 is a small diameter hole, the screw-type anchor 1 can be fixed to the structure 100 with sufficient strength by setting the axial length of the first shank 11 (T1 shown in FIG. 3) to a sufficient length. In addition, because the length of the second shaft 12 is longer than the depth of the first hole 111, the screw-in anchor 1 has the mounting portion 14 protruding downward from the underside 101 of the body 100, and a suspended object can be attached to the mounting portion 14.

Figure 9 is a diagram showing an example in which a workpiece 30 is attached to the mounting portion 14 of a screw-in anchor 1 fixed to a structure 100. For example, the workpiece 30 is a support member that supports a suspended object. A hole is formed in the workpiece 30 through which the second shaft portion 12 is inserted, and the second shaft portion 12 is inserted into the hole. The workpiece 30 is then positioned so that it is joined to, for example, the underside 101 of the structure 100. After that, a nut 31 is attached to the mounting portion 14 of the second shaft portion 12, and the nut 31 is tightened, so that the screw-in anchor 1 supports the workpiece 30 on the underside 101 side of the structure 100.

As described above, the screw-in anchor 1 is configured to support the workpiece 30 by attaching the nut 31 to the second shaft portion 12. The second shaft portion 12 has a larger diameter than the first shaft portion 11, and therefore has a high shear strength. Therefore, for example, in the event of an earthquake, as shown in FIG. 9, even if a large force F acts on the workpiece 30 in the lateral direction, the second shaft portion 12 will not be sheared off. In addition, the step portion 19 where the first shaft portion 11 is connected to the second shaft portion 12 is vertically separated from the workpiece 30 that is vibrated horizontally by the force F, and the outer periphery of the portion (threadless portion 16) of the second shaft portion 12 embedded in the first hole 111 is in close proximity to the inner periphery wall of the first hole 111. Therefore, even if a large force F acts on the workpiece 30 in the lateral direction, the amplitude of the second shaft portion 12 is reduced, and the shear stress acting on the first shaft portion 11 is reduced. Therefore, the first shaft portion 11 will not be sheared off when an earthquake occurs. Therefore, the screw-type anchor 1 of this embodiment can effectively prevent the shaft portion 10 from being sheared off when an earthquake occurs, and is configured to be more efficient than conventional anchors when attached to the building frame 100.

The mounting portion 14 of the screw-type anchor 1 may also be configured to allow a bolt such as a suspension bolt to be attached. FIG. 10 is a diagram showing an example of a configuration in which a bolt 36 can be attached to the mounting portion 14 of the screw-type anchor 1. The mounting portion 14 of this screw-type anchor 1 includes a second male thread portion 15 formed on the outer circumferential surface of the second shaft portion 12, and a long nut 35 attached to the second male thread portion 15. As shown in FIG. 10, the length of the long nut 35 is formed to be longer than the second shaft portion 12 that protrudes downward from the lower surface 101 of the body 100.

For example, the screw-in anchor 1 is fixed to the mounting hole 110 of the body 100 with the long nut 35 removed from the second male thread portion 15. The long nut 35 is then attached to the second male thread portion 15, and the bolt 36 is screwed into the lower opening of the long nut 35, so that the screw-in anchor 1 supports the bolt 36 in a suspended state.

The screw-type anchor 1 can also be fixed to the mounting hole 110 of the structure 100 with the long nut 35 attached to the second male screw portion 15. That is, by attaching a socket bit to the bottom of the long nut 35 and operating a power tool, the screw-type anchor 1 can be screwed into the mounting hole 110 of the structure 100 and fixed. When using this construction method, it is not necessary to provide an engagement portion 17 at the rear end of the second shaft portion 12.

The screw-in anchor 1 as described above is attached, for example, with the top surface of the long nut 35 joined to the bottom surface 101 of the body 100. Furthermore, if an earthquake occurs with the bolt 36 attached to the long nut 35, the bolt 36 vibrates laterally (X direction). This vibration acts as a force F that shakes the second shaft portion 12 in the left-right direction at the top of the long nut 35. However, since the second shaft portion 12 has a larger diameter than the first shaft portion 11 and has a higher shear strength, the second shaft portion 12 will not be sheared off. In other words, the screw-in anchor 1 shown in FIG. 10 is capable of continuously supporting the bolt 36 with sufficient strength even when the bolt 36 is attached to the mounting portion 14.

Although one embodiment of the present invention has been described above, the present invention is not limited to the embodiment described above. In other words, the present invention includes various modified versions of the embodiments described above.

For example, in the above embodiment, as shown in FIG. 11(a), the engaging portion 17 is formed as a hexagonal protrusion 18 protruding from the rear end surface 12a of the second shaft portion 12. However, the engaging portion 17 is not necessarily limited to being formed by such a protrusion 18. For example, the engaging portion 17 may be formed as a hexagonal recess 38 on the rear end surface 12a of the second shaft portion 12 as shown in FIG. 11(b). Even when the engaging portion 17 is formed as a hexagonal recess 38, it is possible to attach and detach a tool that applies a rotational torque to the second shaft portion 12.

In the above embodiment, the diameter of the second shaft portion 12 is approximately twice as large as the diameter of the first shaft portion 11, but the diameter of the second shaft portion 12 is not limited to approximately twice the diameter of the first shaft portion 11. For example, the diameter of the second shaft portion 12 may be approximately 1.5 times the diameter of the first shaft portion 11, or may be three times or more. What is important here is the thickness (first diameter) of the first shaft portion 11. In order to be able to smoothly form the mounting hole 110, it is preferable that the thickness (first diameter) of the first shaft portion 11 is, for example, φ6 mm or less.

In the above embodiment, an example was described in which the screw-type anchor 1 was installed on the underside 101 of the structure 100, but the installation position of the screw-type anchor 1 is not necessarily limited to the underside 101 of the structure 100. It goes without saying that the above-mentioned screw-type anchor 1 can be installed not only on the ceiling, but also on a wall or floor.

1...screw-in anchor, 10...shaft, 11...first shaft, 12...second shaft, 13...first male screw, 14...mounting portion, 15...second male screw, 17...engagement portion, 31...nut, 35...long nut, 36...bolt, 100...body, 110...mounting hole, 111...first hole, 112...second hole.

Claims (5)

A screw-type anchor is fixed to a skeleton by being screwed into an attachment hole having a first hole formed on a surface of the skeleton and a second hole having a smaller diameter than the first hole formed at a back end of the first hole,
A shaft portion is inserted into the mounting hole,
the shaft portion includes a first shaft portion having a small diameter and provided at a tip end side and capable of being inserted into the second hole, and a second shaft portion having a larger diameter than the first shaft portion and provided at a rear end side of the first shaft portion, capable of being inserted into the first hole but not capable of being inserted into the second hole ;
a first male screw portion is formed on an outer circumferential surface of the first shaft portion and is screwed into an inner circumferential wall of the second hole in a state where the first male screw portion is bitten into the inner circumferential wall of the second hole;
When the first male screw portion is screwed into an inner peripheral wall of the second hole and the shaft portion is fixed to the mounting hole, the second shaft portion protrudes from the inside of the mounting hole to the outside of the body surface,
a second male screw portion, to which a nut can be attached, is formed on an outer peripheral surface of the second shaft portion that protrudes outward from the surface of the body, and the second male screw portion has a larger diameter than the first male screw portion . The screw-type anchor according to claim 1, characterized in that the second shaft portion is arranged with its tip abutting the inner end of the first hole. The screw-type anchor according to claim 1 or 2, characterized in that the second shaft portion is arranged in such a manner that the outer periphery of the portion embedded in the first hole is in close proximity to the inner periphery wall of the first hole. 4. The threaded anchor according to claim 1, wherein a long nut is attached to the second male thread portion , and a bolt can be attached to the long nut. 5. The screw-type anchor according to claim 1, wherein the second shank has an engagement portion at a rear end of the second male thread portion to which a tool that applies a rotational torque to the second shank can be attached and detached.

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