Screw-in anchor

Abstract

To provide a screw type anchor where a shaft is not sheared when earthquake occurs and that can mount it efficiently as compared to conventional one when mounting on a skeleton.SOLUTION: A fitting hole 110 has a first hole 111 formed onto the surface of a skeleton 100 and a second hole 112 formed at the deep end part of the first hole 111 and having a smaller diameter than the first hole 111. A screw type anchor 1 screwing into the fitting hole 110 has a shaft 10. The shaft 10 has a small diameter first shaft 11 provided at a tip side and capable of being inserted into the second hole 112 and a second shaft 12 provided at a rear end side of the first shaft 11 and having a larger diameter than the first shaft 11 and capable of being inserted into the first hole 111. A male screw part 13 screwed in an inner peripheral wall of the second hole 112 is formed at the first shaft 11. The second shaft 12 has an attaching part 14 longer than a depth of the first hole 111 and capable of attaching a nut or a bolt to the portion projecting from the surface of the skeleton 100.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an anchor fixed to various structures such as concrete buildings and structures, and particularly to a screw-in type anchor that is screwed into a mounting hole formed in the structure for attachment.

Background Art

[0002] In an existing ceiling structure such as a concrete building, when suspending suspended objects such as air conditioners, lighting fixtures, and various pipes, an anchor for supporting the suspended object is attached to the structure. Conventionally, as this type of anchor, a screw-in type anchor is known in which a mounting hole (lower hole) for attaching the anchor is formed on the surface of the structure, and the anchor is screwed into the mounting hole for fixation (for example, Patent Documents 1, 2, and 3).

[0003] These conventional screw-in type anchors have a male screw portion formed at the tip of a shaft portion having a predetermined diameter, and can be fixed to the structure by screwing the male screw portion into a mounting hole formed in the structure. Further, the conventional screw-in type anchor has a structure in which the other end of the shaft portion protrudes from the surface of the structure, and a work such as a suspended object can be attached to the shaft portion.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] Incidentally, the drilling operation of forming mounting holes on the surface of the body becomes more difficult as the hole diameter increases. For example, when the hole diameter increases, the bit diameter of the drill bit becomes larger, and a large force is required when pressing an electric tool such as a vibration drill or a hammer drill against the body, making the drilling operation difficult. In particular, when trying to form a mounting hole perpendicular to the ceiling portion of the body, it is a high-place drilling operation, so there is a problem of poor work efficiency. Also, when the hole diameter increases, a large amount of concrete cutting chips are generated and fall from the hole during drilling, further reducing the work efficiency. To solve these problems, it is necessary to reduce the hole diameter of the mounting hole.

[0006] For example, FIG. 12 is a diagram showing an example of a conventional screw-in anchor 200. This screw-in anchor 200 has a first male screw portion 201 formed on 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 formed on the rear end side of the shaft portion. On the other hand, a mounting hole 102 having the same diameter as or slightly larger than the diameter of the shaft portion of the screw-in anchor 200 is formed in the lower surface 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 on the tip side of the shaft portion into the mounting hole 102. Further, when the screw-in anchor 200 is fixed to the body 100, the second male screw portion 202 formed on the rear end side of the shaft portion protrudes from the lower surface 101 of the body 100. Then, a work 30 for supporting a suspended object is mounted on the second male screw portion 202 protruding from the lower surface 101 of the body 100, and the work 30 is supported by tightening a nut 31.

[0007] In the configuration as described above, if the diameter of the mounting hole 102 becomes small, for example, about φ5 to 6 mm, the diameter of the shaft portion of the screw-in anchor 200 screwed into the mounting hole 102 also becomes small, for example, about φ5 to 5.5 mm. Therefore, the shear strength of the shaft portion decreases. For example, when a large lateral force F (see Fig. 12(a)) acts on the workpiece 30 during an earthquake, the force F acts as a shear stress that shears the shaft portion at the interface between the workpiece 30 and the lower surface 101 of the housing 100. The shear stress is inversely proportional to the cross-sectional area of the shaft portion. Therefore, the smaller the diameter of the shaft portion, the greater the shear stress acting on the shaft portion. Therefore, if the diameter of the shaft portion of the screw-in anchor 200 is made thinner as the diameter of the mounting hole 102 is decreased, as shown in Fig. 12(b), the shaft portion of the screw-in anchor 200 may be sheared during an earthquake, causing the workpiece 30 to fall from the ceiling.

[0008] Therefore, the conventional screw-in anchor 200 is not allowed to have a thin shaft diameter, and the diameter of the mounting hole 102 for mounting the screw-in anchor 200 is not allowed to be decreased. Due to such circumstances, conventionally, the diameter of the mounting hole 102 formed in the lower surface 101 of the housing 100 cannot be decreased, and the drilling operation cannot be performed efficiently. As a result, there is a problem that the operation of attaching the screw-in anchor to the housing cannot be performed efficiently.

[0009] The present invention has been made to solve the above-described conventional problems, and an object thereof is to provide a screw-in anchor that is not sheared at the shaft portion during an earthquake and can be attached more efficiently than conventionally when attached to a housing.

Means for Solving the Problems

[0010] To achieve the above object, first, the present invention provides a screw-in anchor that is fixed to the body by screwing into a mounting hole formed on the body surface, where a first hole is formed and a second hole with a smaller diameter than the first hole is formed at the inner end of the first hole. The screw-in anchor has a shaft portion inserted into the mounting hole. The shaft portion includes a first shaft portion with a small diameter provided at the tip side and insertable into the second hole, and a second shaft portion provided at the rear end side of the first shaft portion, having a larger diameter than the first shaft portion and insertable into the first hole. The first shaft portion is formed with a male screw portion that is screwed into the inner peripheral wall of the second hole in a state of biting into it. This is the configuration characterized by this. and cannot be inserted into the second hole Second, the present invention provides a screw-in anchor having the above first configuration, characterized in that the second shaft portion is arranged with its tip in contact with the inner end of the first hole. outer peripheral surface Third, the present invention provides a screw-in anchor having the above first or second configuration, characterized in that the second shaft portion is arranged such that the outer peripheral portion of the portion embedded in the first hole is close to the inner peripheral wall of the first hole. first Fourth, the present invention provides a screw-in anchor having any of the above first to third configurations, characterized in that the screw-in anchor is a long nut and a bolt can be attached to the long nut. 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 housing 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 protruding to the outside of the housing surface, and the second male screw portion has a larger diameter than the first male screw portion Fifth, the present invention provides a screw-in anchor having any of the above first to fourth configurations, characterized in that the second shaft portion is provided with an engaging portion at the rear end thereof, to which a tool for applying rotational torque to the second shaft portion can be detachably attached.

[0011]

Advantages of the Invention

[0012]

[0014] 4 Fourth onto the second male screw portion In the screw-in anchor having any of the above first to third configurations, the screw-in anchor is mounted is a long nut and a bolt can be attached to the long nut. This is the configuration characterized by this.

[0015] 5 Fifth 4 In the screw-in anchor having any of the above first to fourth configurations, the second shaft portion second male screw portion is provided with an engaging portion at the rear end thereof, to which a tool for applying rotational torque to the second shaft portion can be detachably attached. This is the configuration characterized by this.

[0016] ​​​According to the present invention, it is possible to provide a screw-in anchor in which the shaft portion is not sheared during an earthquake and which can be attached more efficiently than in the past when attaching to a housing.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Embodiments for Carrying Out the Invention

[0018] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In each of the drawings referred to below, members common to each other are denoted by the same reference numerals, and redundant descriptions thereof are omitted.

[0019] FIG. 1 is a perspective view showing a screw-in anchor 1 according to an embodiment of the present invention. FIG. 2 is a side view of the screw-in anchor 1. This screw-in anchor 1 is an anchor that is screwed into and fixed to various structures such as concrete buildings and structures, and is particularly suitable for attachment to ceiling structures such as ceiling bodies. The screw-in anchor 1 has a shaft portion 10 made of a metal rod-shaped member. The shaft portion 10 has a first shaft portion 11 provided on the tip side and a second shaft portion 12 provided on the rear end side of the first shaft portion 11. The first shaft portion 11 is provided in an area approximately half of the tip side (upper end side in FIGS. 1 and 2) of the shaft portion 10, and the second shaft portion 12 is provided in an area approximately half of the rear end side (lower end side in FIGS. 1 and 2) of the shaft portion 10.

[0020] 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 peripheral surface. The first male screw portion 13 is formed as a tapping screw for fixing the screw-in anchor 1 to the body by being screwed into a mounting 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 including a large-diameter first thread 13a and a small-diameter second thread 13b. However, the spiral structure of the first male screw portion 13 may be formed only by the large-diameter first thread 13a. The first male screw portion 13 can enter the mounting hole 110 formed in the body 100 with the first shaft portion 11 by such a spiral structure. The first shaft portion 11 is formed to have a smaller diameter than the second shaft portion 12.

[0021] The second shaft portion 12 has the same axis as the first shaft portion 11 and has a second diameter (for example, about φ9 to 10 mm) that is about twice as large as the first diameter, and is provided with a mounting portion 14 on the outer peripheral surface of the rear end side thereof where a nut can be mounted. The second shaft portion 12 is thicker than the first shaft portion 11. Therefore, a stepped 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 mounting portion 14 includes a second male screw portion 15 formed on the outer peripheral surface of the second shaft portion 12. The second male screw portion 15 is formed as a metric screw. The second male screw portion 15 is formed from a position separated by a predetermined distance from the stepped portion 19 toward the rear end side of the second shaft portion 12. Therefore, the second shaft portion 12 is provided with a screwless portion 16 in the vicinity region of the stepped portion 19 (specifically, the region from the stepped portion 19 to a predetermined distance).

[0022] Further, the second shaft portion 12 is provided with an engaging portion 17 at the rear end portion of the mounting portion 14, which can detachably attach a tool for applying a rotational torque to the second shaft portion 12. For example, the engaging 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 axes of the first shaft portion 11 and the second shaft portion 12. Note that the shape of the protrusion 18 is not necessarily limited to hexagonal, and it may be square. Also, the outer diameter dimension of the protrusion 18 is smaller than the outer diameter dimension of the second shaft portion 12. Therefore, when a nut is mounted on the second male screw portion 15, the nut does not interfere with the protrusion 18.

[0023] FIG. 3 is a view illustrating the mounting hole 110 in which the screw-in anchor 1 is installed. A mounting hole 110 as shown in FIG. 3 is formed in the lower surface 101 of the housing 100 in which the screw-in anchor 1 is installed. The mounting hole 110 is composed of a first hole 111 formed in the surface (lower surface 101) of the housing 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 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 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. Further, the depth H1 of the first hole 111 is formed to be substantially the same dimension as the height T2 of the threadless portion 16 provided on the second shaft portion 12 of the screw-in anchor 1. However, the height T2 of the threadless portion 16 may be formed lower than the depth H1 of the first hole 111. Furthermore, the depth H2 of the second hole 112 is formed deeper than the depth H1 of the first hole 111 and further deeper than the height T1 of the first shaft portion 11 of the screw-in anchor 1.

[0024] 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. Such a mounting hole 110 may be formed, for example, on the lower surface 101 of the housing 100 by first forming the second hole 112 with a small diameter 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 with different diameters to form the mounting hole 110 in the housing 100. That is, first, a drill bit with a small diameter is attached to a power tool such as a vibration drill or a hammer drill to form the second hole 112, and then it is necessary to replace it with a drill bit with a large diameter to form the first hole 111. In this case, when forming the second hole 112, since a drill bit with a small diameter can be used for drilling, the force pressing the power tool against the housing 100 can be reduced, and the drilling operation can be performed smoothly. Also, since the depth H1 of the first hole 111 formed on the front side of the second hole 112 using a drill bit with a large diameter is relatively shallow, the force pressing the power tool against the housing 100 does not increase, and the drilling operation can be performed smoothly. However, in this case, since it is necessary to replace the drill bit during the drilling operation, the working efficiency cannot be significantly improved. Therefore, it is preferable to use a drill bit as shown below.

[0025] FIG. 4 is a view showing a drill bit 20 that can form the first hole 111 and the second hole 112 in a single drilling operation. This drill bit 20 has a drill blade 21 for forming the first hole 111 in the housing 100, an expansion blade 22 provided at the rear end portion of the drill blade 21, and a hexagonal attachment portion 23 for attaching the drill bit 20 to the chuck portion of a power tool. The drill blade 21 is provided at the tip of the drill bit 20, and the attachment 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 attachment portion 23 and is formed in a blade shape protruding outward from the outer peripheral surface of the drill bit 20. This expansion blade 22 forms the second hole 112 near the lower surface 101 of the housing 100.

[0026] The diameter D2 of the drill blade 21 is approximately equal to the diameter D2 of the second hole 112 of the mounting hole 110 formed in the housing 100. Also, 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 housing 100. Further, the length L2 of the drill blade 21 is approximately equal to the depth H2 of the second hole 112 of the mounting hole 110 formed in the housing 100. Also, the length L1 of the expansion blade 22 is approximately equal to, for example, the depth H1 of the first hole 111 of the mounting hole 110 formed in the housing 100. However, the length L1 of the expansion blade 22 may be shorter than the depth H1 of the first hole 111.

[0027] FIG. 5 is a diagram showing a procedure for drilling the mounting hole 110 in the housing 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 blade 21 is pressed against the position where the mounting hole 110 is to be formed on the lower surface 101 of the housing 100, and the power tool 28 is operated to form the second hole 112 in the housing 100. The diameter D2 of the drill blade 21 is smaller than the diameter of the drill blade for forming a mounting hole for screwing in a conventional screw-in anchor. Therefore, when forming the second hole 112 in the housing 100, the force pressing the power tool 28 against the housing 100 can be reduced, and the drilling operation can be performed smoothly. After that, when the expansion blade 22 hits the lower surface 101 of the housing 100, as shown in FIG. 5(b), the expansion blade 22 scrapes off the peripheral portion of the second hole 112 to form the large-diameter first hole 111 below the second hole 112. At this time, since the force pressing the power tool 28 against the housing 100 does not become so large, the drilling operation can be continued smoothly. Also, since the force pressing the power tool 28 against the housing 100 can be reduced, the fatigue of the operator can also be reduced. Then, when the rear end of the expansion blade 22 advances to the position of the lower surface 101 of the housing 100, the drilling operation of the mounting hole 110 is completed.

[0028] By using the drill bit 20 shown in FIG. 4 as described above, it is possible to form the mounting hole 110 having a two-stage structure of the first hole 111 and the second hole 112 in a series of drilling operations. That is, since the mounting hole 110 can be formed in a single drilling operation without replacing the drill bit, the working efficiency can be improved. When the mounting hole 110 is formed in the lower surface 101 of the housing 100, the screw-in type anchor 1 is attached to the mounting hole 110.

[0029] FIGS. 6 to 8 are views showing the procedure for attaching the screw-in type anchor 1 to the mounting hole 110. As shown in FIG. 6, when the screw-in type anchor 1 is attached to the mounting hole 110, a socket bit 27 with a hexagonal hole is attached to an engaging 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 a power tool. Then, the first shaft portion 11 is inserted into the mounting hole 110, and with the tip of the first shaft portion 11 in contact with the peripheral edge of the second hole 112, the power tool is operated to rotate the socket bit 27 in a predetermined rotational direction R. At this time, the operator can 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 by pressing the power tool upward as shown in FIG. 7. At this time, since the first shaft portion 11 is screwed into the small-diameter second hole 112, the force when the operator presses the power tool upward can be reduced. Therefore, it is possible to smoothly perform the operation of screwing the first shaft portion 11 into the second hole 112. Also, since the force when pressing the power tool upward can be reduced, the fatigue of the operator can be alleviated.

[0030] As the first shaft portion 11 is screwed into the second hole 112, the second shaft portion 12 enters the first hole 111. Then, as shown in FIG. 8, when the stepped portion 19 at the tip of the second shaft portion 12 abuts against the inner end of the first hole 111, the installation of the screw-in anchor 1 to the housing 100 is completed. At this time, the entire first male screw portion 13 formed on the first shaft portion 11 is screwed into the second hole 112. For example, even if the second hole 112 is a small-diameter hole, by setting the axial length (T1 shown in FIG. 3) of the first shaft portion 11 to be a sufficient length, the screw-in anchor 1 will be fixed to the housing 100 with sufficient strength. Also, since the length of the second shaft portion 12 is longer than the depth of the first hole 111, the screw-in anchor 1 is in a state where the mounting portion 14 protrudes downward from the lower surface 101 of the housing 100, and a suspended object can be attached to the mounting portion 14.

[0031] FIG. 9 is a view showing an example in which a workpiece 30 is attached to the mounting portion 14 of the screw-in anchor 1 fixed to the housing 100. For example, the workpiece 30 is a support member that supports a suspended object. A hole through which the second shaft portion 12 is inserted is formed in the workpiece 30, and the second shaft portion 12 is inserted through the hole. Then, the workpiece 30 is arranged in a state of being joined to, for example, the lower surface 101 of the housing 100. Thereafter, a nut 31 is attached to the mounting portion 14 of the second shaft portion 12, and when the nut 31 is tightened, the screw-in anchor 1 supports the workpiece 30 on the lower surface 101 side of the housing 100.

[0032] As described above, the screw-in anchor 1 is configured such that a nut 31 is attached to the second shaft portion 12 and supports the workpiece 30. Since the second shaft portion 12 has a larger diameter than the first shaft portion 11, it has a high shear strength. Therefore, for example, even when a large lateral force F acts on the workpiece 30 as shown in FIG. 9 during an earthquake, the second shaft portion 12 will not be sheared. Further, the stepped portion 19 where the first shaft portion 11 is connected to the second shaft portion 12 is separated vertically from the horizontally vibrating workpiece 30 by the force F, and moreover, the outer peripheral portion of the portion (portion without screw 16) of the second shaft portion 12 that is embedded in the first hole 111 is in a state close to the inner peripheral wall of the first hole 111. Therefore, even when a large lateral force F acts on the workpiece 30, the swing amplitude of the second shaft portion 12 becomes small, so the shear stress acting on the first shaft portion 11 becomes small. Therefore, the first shaft portion 11 will not be sheared during an earthquake. Thus, the screw-in anchor 1 of the present embodiment can preferably prevent the shaft portion 10 from being sheared during an earthquake, and moreover, it has a configuration that enables more efficient attachment when attaching to the housing 100 than in the prior art.

[0033] Further, the attachment portion 14 of the screw-in anchor 1 may be configured to be able to attach a bolt such as a suspension bolt. FIG. 10 is a diagram showing a configuration example in which a bolt 36 can be attached to the attachment portion 14 of the screw-in anchor 1. The attachment portion 14 of this screw-in anchor 1 includes a second male screw portion 15 formed on the outer peripheral surface of the second shaft portion 12 and a long nut 35 attached to the second male screw portion 15. As shown in FIG. 10, the length of the long nut 35 is formed longer than the second shaft portion 12 that protrudes downward from the lower surface 101 of the housing 100.

[0034] For example, the screw-in anchor 1 is fixed to the mounting hole 110 of the housing 100 with the long nut 35 removed from the second male screw portion 15. Thereafter, the long nut 35 is attached to the second male screw portion 15, and the bolt 36 is screwed in from the lower opening of the long nut 35, whereby the screw-in anchor 1 supports the bolt 36 in a suspended state.

[0035] Also, the screw-in anchor 1 can be fixed to the mounting hole 110 of the housing 100 while the long nut 35 is attached to the second male screw portion 15. That is, by attaching a socket bit to the lower part of the long nut 35 and operating a power tool, the screw-in anchor 1 can be screwed into and fixed to the mounting hole 110 of the housing 100. Incidentally, when such a construction method is adopted, it is not necessary to provide the engaging portion 17 at the rear end portion of the second shaft portion 12.

[0036] The screw-in anchor 1 as described above is attached, for example, in a state where the upper surface of the long nut 35 is joined to the lower surface 101 of the housing 100. Also, when an earthquake occurs with the bolt 36 attached to the long nut 35, the bolt 36 vibrates in the lateral direction (X direction). This vibration acts as a force F that swings the second shaft portion 12 in the left-right direction at the upper part 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 high shear strength, the second shaft portion 12 will not be sheared. That is, the screw-in anchor 1 shown in FIG. 10 can continuously support the bolt 36 with sufficient strength even when the bolt 36 is attached to the mounting portion 14.

[0037] As described above, an embodiment of the present invention has been described, but the present invention is not limited to what has been described in the above embodiment. That is, the present invention includes those to which various modifications of what has been described in the above embodiments are applied.

[0038] For example, in the above embodiment, as shown in FIG. 11(a), the case where the engaging portion 17 is formed as a hexagonal protrusion 18 protruding from the rear end surface 12a of the second shaft portion 12 is illustrated. 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 with respect to the rear end surface 12a of the second shaft portion 12 as shown in FIG. 11(b). Even when the engaging portion 17 is a hexagonal recess 38, it is possible to attach and detach a tool that applies rotational torque to the second shaft portion 12.

[0039] Also, in the above-described embodiment, the case where the diameter of the second shaft portion 12 is about twice as large as the diameter of the first shaft portion 11 is illustrated. However, the diameter of the second shaft portion 12 is not limited to about twice the diameter of the first shaft portion 11. For example, the diameter of the second shaft portion 12 may be about 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, for example, the thickness (first diameter) of the first shaft portion 11 is preferably φ6 mm or less.

[0040] Also, in the above-described embodiment, the example of installing the screw-in anchor 1 on the lower surface 101 of the housing 100 is described. However, the installation position of the screw-in anchor 1 is not necessarily limited to the lower surface 101 of the housing 100. Needless to say, the above-described screw-in anchor 1 can be installed not only on the ceiling but also on the wall surface and the floor surface.

Explanation of Reference Numerals

[0041] 1... Screw-in anchor, 10... Shaft portion, 11... First shaft portion, 12... Second shaft portion, 13... First male screw portion, 14... Mounting portion, 15... Second male screw portion, 17... Engaging portion, 31... Nut, 35... Long nut, 36... Bolt, 100... Housing, 110... Mounting hole, 111... First hole, 112... Second hole.

Claims

1. A screw-in anchor that is fixed to the body by screwing into a mounting hole in which a first hole is formed on the body surface, and a second hole having a smaller diameter than the first hole is formed at the inner end of the first hole, having a shaft portion inserted into the mounting hole, the shaft portion is provided on the tip side, a first shaft portion having a small diameter that can be inserted into the second hole, and is provided on the rear end side of the first shaft portion, having a larger diameter than the first shaft portion, being insertable into the first hole, and having a second shaft portion that cannot be inserted into the second hole, a first male screw portion that is screwed into the inner peripheral wall of the second hole in a state of biting into the outer peripheral surface of the first shaft portion is formed, when the first male screw portion is screwed into the inner peripheral wall of the second hole in a state of biting in, and the shaft portion is fixed to the mounting hole, the second shaft portion protrudes from the inner side of the mounting hole to the outer side of the body surface, a second male screw portion to which a nut can be attached is formed on the outer peripheral surface of the second shaft portion protruding to the outer side of the body surface, and the second male screw portion is characterized by having a larger diameter than the first male screw portion. Screw-in anchor.

2. The screw-in anchor according to claim 1, wherein the second shaft portion is arranged in a state where the tip abuts against the inner end of the first hole.

3. The screw-in anchor according to claim 1 or 2, wherein the second shaft portion is arranged in a state where the outer peripheral portion of the portion embedded in the first hole is close to the inner peripheral wall of the first hole.

4. The screw-in anchor according to any one of claims 1 to 3, wherein a long nut is attached to the second male screw portion, and a bolt can be attached to the long nut.

5. The screw-in anchor according to any one of claims 1 to 4, wherein the second shaft portion is provided with an engaging portion at the rear end portion of the second male screw portion, which can be attached and detached with a tool for applying rotational torque to the second shaft portion.

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