JP2022121089A - Post-construction anchor - Google Patents

Abstract

An object of the present invention is to provide a post-construction anchor that facilitates attachment to and removal from a building frame. A post-installed anchor (1) comprises an anchor body (4) consisting of a front body (2) and a rear body (3), a screw shaft (5) held by the anchor body (4), and a nut (6) screwed onto the screw shaft (5). It is The front body 2 has a female thread 2a into which the male thread 5b of the screw shaft 5 is screwed, and the end face on the side of the rear body 3 is formed as a first inclined cam surface 2b. The outer peripheral surface of the front body 2 has a bellows shape with annular projections 2c formed at regular intervals. The rear body 3 has a parallel hole 3a into which the straight portion 5a of the screw shaft 5 is loosely fitted, and the end face on the side of the front body 2 is formed as a second inclined cam surface 3b. The outer peripheral surface of the rear main body 3 also has a bellows shape with annular projections 3c formed at regular intervals. [Selection drawing] Fig. 2

Description

TECHNICAL FIELD The present invention relates to post-installed anchors used at construction sites, and to techniques for facilitating attachment to and removal from a building framework.

A post-construction anchor is a device for installing a scaffolding or the like on the outer wall of an existing building, and is often used for large-scale repairs of housing complexes and office buildings. A post-installed anchor has an anchor body that is inserted into an anchor fixing hole in the building frame and a threaded portion (male or female thread) that is integral with the anchor body. be concluded. In addition, post-installed anchors are classified into metal anchors and adhesive anchors according to the method of fixing them to the anchor fixing holes, but metal anchors having an expansion part that expands inside the anchor fixing holes are the mainstream ( See Patent Documents 1 to 4).

With metal anchors, the expansion part with the slit expands with plastic deformation, so it cannot be removed from the anchor fixing hole when large-scale repairs are completed. Since the anchor becomes disposable, there is a problem such as an increase in the cost required for repair. Therefore, there is a method in which the anchor body to be inserted into the anchor fixing hole is made of a shape memory alloy, and when it becomes unnecessary, the anchor body is heated to return to its original shape (Patent Document 1). A method of returning the anchor body to its original shape by providing a tapered female thread in the taper female thread and loosening the male screw with a hexagonal hole (so-called cat screw) screwed into this tapered female thread (Patent Document 2), the screw hole of the anchor body that is no longer needed A method (Patent Document 4) has been proposed in which a countersunk screw is screwed into the anchor fixing hole and the gap between the anchor fixing hole and the countersunk screw is sealed with a sealing material.

Japanese Utility Model Laid-Open No. 2-141002 Japanese Patent Application Laid-Open No. 2004-74300 Japanese Patent Application Laid-Open No. 2004-339797 Utility Model Registration No. 3179279

The conventional post-installed anchors described above have the following problems. For example, in the method of Patent Document 1, the unit price of the post-installed anchor increases due to the use of a high-cost shape memory alloy as the material for the anchor body, and a heating means such as a heater is required. Less efficient. In addition, in the method of Patent Document 2, since the material of the anchor body must be an expensive material (spring steel, etc.) with high elasticity, machining becomes difficult, and the unit price of the post-installed anchor is low. becomes higher. In addition, in the method of Patent Document 4, since post-installed anchors are left on the building frame, even if sealing is performed with a sealing material, rusting or the like of screw holes due to long-term neglect cannot be avoided.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a construction anchor that can be easily attached to or removed from a building frame.

The post-installed anchor of the present invention comprises an anchor body inserted into an anchor fixing hole of a building frame, a screw shaft held by the anchor body and protruding from the surface of the building frame, and a nut screwed onto the screw shaft. wherein the anchor main body is positioned on the bottom surface side of the anchor fixing hole and on the surface side of the building frame when the anchor main body is inserted into the anchor fixing hole. The front main body is integrated with the screw shaft, and the end face on the rear main body side is formed on a first inclined cam surface inclined with respect to the axial direction of the anchor fixing hole, The rear body has a tubular shape into which the screw shaft is loosely fitted, and an end face on the front body side is formed on a second inclined cam surface facing the first inclined cam surface. The rear main body is driven toward the front main body by being tightened along, and at least one of the front main body and the rear main body is pressed against the inner peripheral surface of the anchor fixing hole. , a convex portion is formed to restrain the movement of the anchor body in the axial direction.

Preferably, said threaded shaft is screwed into a threaded hole formed in said front body.

Preferably, the screw shaft has a projection projecting from the front end of the front body, and the screw shaft and the front body are fastened by a lock nut screwed into the projection.

Preferably, said front body and said screw shaft are made from a single piece of material.

Preferably, the projections are annular projections formed at predetermined intervals in the axial direction.

According to the post-installed anchor of the present invention, when the nut screwed onto the screw shaft is tightened after the anchor main body is fitted into the anchor fixing hole of the building frame, the rear main body is pressed against the front main body. As a result, a slip occurs between the first inclined cam surface and the second inclined cam surface, and both anchor bodies, which have moved in the radial direction, are pressed against the inner peripheral surface of the anchor fixing hole, and the convex portion bites into the anchor. Firmly fixed to the building frame. On the other hand, when the nut is loosened, the force that urges the rear body and the front body against the inner peripheral surface of the anchor fixing hole disappears, and the post-installed anchor can be pulled out by pulling the screw shaft outward.

Further, in the case where the screw shaft is screwed into the screw hole formed in the front body, the screw shaft and the front body are reliably integrated.

Further, in the case where the screw shaft has a projecting portion projecting from the front end of the front body, and the screw shaft and the front body are fastened by a lock nut screwed into the projecting portion, the screw shaft and the front body are more reliably integrated.

Further, when the front main body and the screw shaft are made of a single material, there is no problem of the screw shaft slipping out of the front main body, and the number of component parts can be reduced.

In addition, when the projections are annular projections formed at predetermined intervals in the axial direction, the movement of the anchor body in the axial direction is strongly suppressed.

FIG. 1 is a side view of a post-installed anchor according to the embodiment. FIG. 2 is a longitudinal sectional view of the post-installed anchor according to the embodiment. 3(a) and 3(b) are cross-sectional views showing the state of use of the post-installed anchor according to the embodiment. FIG. 4 is a longitudinal sectional view of a post-installed anchor according to a first modified example. FIG. 5 is a longitudinal sectional view of a post-installed anchor according to a second modification. 6(a), 6(b), 6(c), 6(d), 6(e), 6(f), 6(g) and 6(h) are embodiments FIG. 6B is a front view, a rear view, a plan view, a bottom view, a cross-sectional view along line AA of FIG.

An embodiment and some modifications of the present invention will be described in detail below with reference to FIGS. 1 to 6. FIG.
[Embodiment]
<Configuration of Embodiment>
As shown in FIGS. 1 and 2, the post-installed anchor 1 of the embodiment includes an anchor body 4 consisting of a front body 2 and a rear body 3, a screw shaft 5 held by the anchor body 4, and a screw shaft 5 and a nut 6 that is screwed to the

The screw shaft 5 is formed by subjecting a steel bar to threading or the like, and includes a smooth straight portion 5a facing the rear body 3, male threads 5b and 5c formed in front and rear of the straight portion 5a, and a male thread 5c. It has a tapered portion 5d which is formed at the rear end (upper side in FIGS. 1 and 2) and serves as a guide when the nut 6 is assembled. As the male threads 5b and 5c, Whitworth threads that are widely used in the construction industry and metric threads for general machines can be used.

The front body 2 is made of a steel bar and has a cylindrical shape with a bottom. It is formed on the first inclined cam surface 2b inclined with an inclination angle. Further, the outer peripheral surface of the front main body 2 is formed in a bellows shape with annular projections 2c formed at regular intervals by rolling or cutting. In addition, the screw shaft 5 is screwed into the front main body 2 with a predetermined torque from the bottomed state so that it does not come off easily from the front main body 2 .

The rear body 3 has a cylindrical shape made of a steel bar having the same outer diameter as that of the front body 2, and has a parallel hole 3a into which the straight portion 5a of the screw shaft 5 is loosely fitted. The end surface is formed on the second inclined cam surface 3b which is inclined at an inclination angle of 45° facing the first inclined cam surface 2b. Similarly to the outer peripheral surface of the front main body 2, the outer peripheral surface of the rear main body 3 is also formed in a bellows shape with annular protrusions 3c formed at regular intervals.

<Action of Embodiment>
When using the post-installed anchor 1 during large-scale repair, the worker first inserts the post-installed anchor 1 into the anchor fixing hole 11 of the building skeleton 10, as shown in FIG. 3(a). The anchor fixing hole 11 is drilled with a concrete drill or the like, and has an inner diameter set slightly larger than the outer diameter of the anchor main body 4 and a depth larger than the overall length of the anchor main body 4 . Specifically, the inner diameter of the anchor fixing hole 11 is set so that the distance between the inner peripheral surface of the anchor fixing hole 11 and the anchor main body 4 is smaller than the distance between the inner peripheral surface of the rear main body 3 and the screw shaft 5. ing.

Next, the operator tightens the nut 6 using a ratchet wrench or the like, and drives (advances) the rear body 3 until it abuts against the front body 2 . When the operator further tightens the nut 6, the first inclined cam surface 2b and the second inclined cam surface 3b slide relative to each other as indicated by the black arrow in FIG. The front body 2 and the rear body 3 move radially.

When the nut 6 is tightened with a predetermined tightening torque, the outer peripheral surfaces of the front body 2 and the rear body 3 are strongly pressed against the anchor fixing hole 11, and the annular protrusions 2c and 3c bite into the inner peripheral surface of the anchor fixing hole 11. . As a result, the post-installed anchor 1 is firmly fixed to the building frame 10 , and the worker can fix the scaffolding metal fitting 16 to the screw shaft 5 using the nut 15 .

When the large-scale repair is completed and the post-construction anchor 1 becomes unnecessary, the worker loosens the nut 6 using a ratchet wrench or the like. Then, the force for pressing the rear main body 3 against the front main body 2 disappears, the front main body 2 and the rear main body 3 are separated from the anchor fixing hole 11, and the post-installed anchor 1 is pulled by pulling the screw shaft 5 and the nut 6 by hand. can be easily removed.

[First modification]
The post-installed anchor 1 of the first modified example has substantially the same configuration as that of the above-described embodiment, but as shown in FIG. That is, the front body 2 has a cylindrical shape with an internal thread 2a extending to its front end, while the screw shaft 5 has a protruding portion 5e that protrudes from the front end of the front body 2. As shown in FIG. A lock nut 20 is screwed onto the male thread 5b of the projecting portion 5e, and the screw shaft 5 is firmly fastened to the front body 2 by the lock nut 20. As shown in FIG. In the first modified example, it is more difficult for the screw shaft 5 to slip out of the front main body 2 as compared with the embodiment. The operation when using the first modified example is the same as that of the embodiment.

[Second modification]
The post-installed anchor 1 of the second modification also has substantially the same configuration as the above embodiment, but as shown in FIG. 5, the front body 2 and the screw shaft 5 are integrated. That is, the front main body 2 and the screw shaft 5 are manufactured from a single steel bar by turning, rolling, or the like. In the second modification, since the front main body 2 and the screw shaft 5 are integral parts, the screw shaft 5 cannot come off from the front main body 2 as a matter of course. The operation during use of the second modified example is also the same as that of the embodiment.

<Effects of Embodiment and Partial Modifications>
In the present embodiment and some modifications, by adopting the above-described configuration, it becomes very easy to remove the post-installed anchor 1 from the anchor fixing hole 11 at the time of completion of large-scale repair or the like, and the post-installed anchor 1 can be removed. Reuse can also be performed smoothly. In addition, since the annular protrusions 2c and 3c formed on the front body 2 and the rear body 3 have a small amount of projection, the post-installed anchor 1 can be effectively prevented from slipping out, and a metal anchor having an expanded portion can be used. In comparison, the aggressiveness to the anchor fixing hole 11 can also be suppressed to a low level.

Although the description of specific embodiments and partial modifications has been completed above, aspects of the present invention are not limited to these. For example, the inclination angles of the first inclined cam surface and the second inclined cam surface are not limited to 45°. The shape, number, etc. of the portions can also be freely set. Also, in the embodiment and some modifications, the front main body and the screw shaft are integrated by screwing, but they may be integrated by adhesion or welding. Further, if the screw shaft is fixed to the front main body by welding or the like at its tip (lower tip in FIG. 1), the portion facing the front main body may be a smooth straight portion. In addition, the specific shape and the like of the post-installed anchor can be changed as appropriate without departing from the gist of the present invention.

INDUSTRIAL APPLICABILITY The present invention can be effectively used for post-installed anchors used at construction sites.

1 Post-Installed Anchor 2 Front Main Body 2a Female Thread 2b First Inclined Cam Surface 2c Annular Projection 3 Rear Main Body 3a Parallel Hole 3b Second Inclined Cam Surface 3c Annular Projection 4 Anchor Body 5 Screw Shaft 5a Straight Part 5b Male Thread 5c Male Thread 6 Nut 10 Building frame 11 Anchor fixing hole 15 Nut 16 Scaffolding fitting 20 Lock nut

Claims (5)

A post-installed anchor comprising an anchor body to be inserted into an anchor fixing hole of a building frame, a screw shaft held by the anchor body and protruding from the surface of the building frame, and a nut screwed onto the screw shaft. hand,
The anchor main body comprises a front main body positioned on the bottom side of the anchor fixing hole and a rear main body positioned on the surface side of the building skeleton when inserted into the anchor fixing hole,
The front body is integrated with the screw shaft, and the end face on the rear body side is formed as a first inclined cam surface inclined with respect to the axial direction of the anchor fixing hole,
The rear body has a tubular shape into which the screw shaft is loosely fitted, and the end face on the front body side is formed as a second inclined cam surface facing the first inclined cam surface,
The nut drives the rear body toward the front body by being tightened along the screw shaft,
At least one of the front main body and the rear main body is formed with a protrusion that suppresses axial movement of the anchor main body by being pressed against an inner peripheral surface of the anchor fixing hole. And then the construction anchor. 2. The post-installed anchor of claim 1, wherein said threaded shaft is screwed into a threaded hole formed in said front body. 4. The screw shaft and the front body are fastened together by a lock nut screwed into the projection, wherein the screw shaft has a projection projecting from the front end of the front body. A post-installed anchor according to claim 1 or claim 2. 2. The post-installed anchor of claim 1, wherein said front body and said threaded shaft are fabricated from a single piece of material. The post-installed anchor according to any one of claims 1 to 4, wherein the projections are annular projections formed at predetermined intervals in the axial direction.

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