JP2936476B1 - Removal anchor - Google Patents

Abstract

An object of the present invention is to provide a removal anchor that satisfies all of the destructibility of a hardened material, material cost, workability, and anchor strength. In a state in which an anchor is constructed, a core material is extracted toward the ground together with an expansion tool fixed to a distal end portion, and a plurality of tension members disposed around the core material are pushed outward as the extraction is performed. In the removal anchor, which expands and breaks the hardened material around the tension member, the core member is sheathed over its entire length, while the tension member disposed around the core member comprises a steel strand. The core member has a bare end protruding distally from the tension member, and an extension device having a tapered cone-shaped wedge portion is provided on the bare end portion. The wedge portion of the extension device is provided with a sheath. It is characterized in that it is inserted into the sheath in advance on the opposite inclined lower end side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a removal anchor that can be pulled out of the ground and collected when it is no longer needed after being constructed in the ground.

[0002]

2. Description of the Related Art Conventionally, as a removal anchor, roughly divided,
An extension tool attached to the tip of the core moves the pulling material outward and the hardening material is destroyed by the outward movement of the tensioning material. The former type, in which the tensile material is moved outward, is superior in the breaking performance of the hardened material.

Japanese Patent Laying-Open No. 52-134210 relates to a proposal of a removal anchor having the former configuration. According to the removal anchor having this configuration, as shown in FIGS. Since the tension member c disposed around the core member a relatively moves outward by the passage of the extended tool b, the hardened material d can be reliably destroyed, and the pull member can be pulled out relatively easily. Can be done, but in the following respects:
In addition, it had many problems.

(A) Since it is necessary to cover the core material a with the tension member c, as shown in FIG. 11, the cross-section of the tension member c has a special shape such as an arc-shaped cross section, which is expensive.

(B) The tensile material c is rigid from the cross-sectional shape and material (for example, steel), which is inconvenient to carry into the site, and difficult to handle even on the construction surface. Insertion may be difficult, resulting in poor workability.

As shown in FIG. 11, more than half of the outer peripheral surface of the tension member is in contact with the adjacent tension member and core material, and the hardening material does not adhere to this contact portion. In order to obtain the same anchoring force with a small adhesion area, it is necessary to use a tensile member having a large cross-sectional area, which also poses problems in workability and construction cost.

An object of the present invention is to provide a removal anchor which satisfies not only the destructibility of the hardened material but also the material cost, workability and anchor strength.

[0008]

To solve the problem of the removal anchor proposed in the above-mentioned publication, the present inventors provide a sheath on the core material and release the tension material from the role of the core material coating. Tried to do. In this way, an arbitrary cross-sectional shape, for example, an inexpensive and flexible steel stranded wire can be applied as the tension member, and the above-mentioned problems A to C can be eliminated. However, when a sheath is applied to the core material, a new problem is encountered in that the traction resistance at the time of pulling out the core material becomes excessive and there is a risk of causing trouble such as breakage of the core material. In order to overcome the new problem, the present inventor further studied and found that the sheath gathered and gathered while wrinkling in the axial direction as the dilator was pulled, and this gathering caused the traction resistance. It has been found that it is possible to eliminate the increase in traction resistance by taking measures to prevent gathering, etc.
Thus, the present invention has been completed.

That is, according to the present invention, in a state in which the anchor is constructed, the core material is pulled out toward the ground together with the expansion tool fixed to the distal end portion, and a plurality of pulling members arranged around the core material are extracted as the core material is pulled out. In the removal anchor that pushes outward and breaks the hardened material around the tension member, the core member is provided with a sheath over the entire length, while the tension member disposed around the core member is Consisting of a steel stranded wire, the core has a tip bare portion projecting distally from the tensile material,
An extension device having a tapered cone-shaped wedge portion is provided on the bare end portion, and the wedge portion of the extension device is pre-inserted into the sheath on the inclined lower end side facing the sheath. Related to removal anchor.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 schematically shows the anchoring state of the removal anchor of the present invention.
Denotes a removal anchor of the present invention, B denotes a hardening material such as cement mortar constituting an anchor trunk, and C denotes a hole.

FIG. 2 shows an enlarged view of the removal anchor A of the present invention. The removal anchor A includes a core 1 and a plurality of tension members 2 arranged around the core 1. As a constituent material of the core member 1 and the tension member 2, a steel stranded wire provided with sheaths 3 and 4 can be used. In the sheath 3 of the core member 1, grease is used for the purpose of reducing resistance when the core member is pulled out. And the like (see FIGS. 3 and 4).

The removal anchor A is divided into a free length portion A ₁ , a fixing length portion A _2, and an extension portion A _{3 in} order from the base end (ground side).

The free length portion A ₁ is a portion which is free from the adhesion with the hardening material B. As shown in FIG. 3, the core material 1 and a plurality of, for example, eight tension members disposed around the core material 1 are provided. 2
, The sheaths 3 and 4 are left as they are to isolate them from the hardening material B.

The fixing length portion A ₂ is a portion that forms a fixing portion by adhering to the hardening material B, and as shown in FIG. Although the sheath 3 is left as it is, the sheath 4 is peeled off from the tension member 2 in order to adhere the tension member to the hardening material B to form a fixing portion.

Since the core 1 is provided with the sheath 3 and is configured to be isolated from the hardening material B, the pulling material 2 disposed around the core 1 isolates the core 1 from the hardening material B. It is not necessary to have such a function, and the cross-sectional shape is not restricted. Therefore, as described above, a steel stranded wire can be used as the tensile member 2, and the steel stranded wire can be obtained as a commercial product at a relatively low cost, and has flexibility, so that it can be carried into a construction site and Handling at the time of anchor construction becomes easy, and workability can be improved.

The extension portion A ₃ is a portion on which the extension device 6 is installed. As shown in FIG. 2, in the extension portion A ₃ , the core material 1 is in a bare state with the sheath protruding portion 3 a left. Originally, it protrudes from the tension member 2 toward the distal end, and the distal end bare portion 1a is provided with an extension 6.

The expander 6 has a cylindrical shape and is fitted and fixed to the bare end 1a of the core material 1 through a through hole 6b at the center, and a tapered cone-shaped wedge 6a is formed on the front half side with respect to the drawing direction. , the small diameter side 6a ₁ of the wedge portion 6a, as shown in exaggerated and enlarged in FIG. 5, bites inserted in the sheath protruding portion 3a. A break 7 (see FIGS. 3 and 4) extending in the axial direction can be formed in the sheath 3. The breaking portion 7 is easily broken when the sheath 3 is pushed out from the inside by the wedge portion 6a, and can be composed of, for example, a thin portion, a perforation, a cut, and the like. Although it may be formed continuously, it may be formed continuously in some cases.

Although the inclination angle of the outer peripheral surface of the wedge portion 6a can be selected from a wide range, it is appropriately selected and determined from a range of about 2 to 10 ° in consideration of the wedge effect and the traction resistance at the time of drawing. By the way, when the inclination angle does not reach 2 °, the axial length of the wedge portion 6a must be considerably increased in order to obtain a predetermined expanding effect, and the wedge portion 6a becomes too long in shape. If it exceeds, the traction resistance at the time of the pulling operation tends to increase, which is not preferable.

[0019] expanding section A ₃ are protected to isolate the extension portion A ₃ from the cured material B when the anchor building cap 8
Is given.

[0020] Figure 6, is shown exaggerated and expanded conditions during pulling operation of the core material 1, as shown in FIG. 5, in the present invention, the small diameter side 6a ₁ of the wedge portion 6a of the expander 6 Core material 1 in advance
6 is inserted into the protruding portion 3a, and as shown in FIG. 6, the inserted portion serves as a guide, and as the core material 1 is pulled out, the wedge portion 6a and the extension device 6 push the sheath 3 outward. Going inside while expanding,
Thus, the sheath 3 can be wrinkled in the axial direction, collected and collected, and can be left as it is in the hardened material B as a drawn residue without generation of gathering. Accordingly, regardless of whether the core material 1 is provided with the sheath 3,
Hardly causes the increase in traction resistance when the core material 1 is pulled out.

To prevent the sheath 3 from gathering, the sheath 3
The sheath 3 is ruptured as the wedge 6a advances, and the lubricating material 5 filled in the sheath 3 further improves the slipperiness of the contact surface between the sheath 3 and the wedge 6a. Can be further ensured by improving.
Further, the formation of the broken portion 7 and the filling of the lubricant 5 are effective in reducing the traction resistance at the time of the operation of pulling out the core material 1.

FIG. 7 shows a state before the destruction of the hardened material B. In the state before the destruction, the hardened material B penetrates into the inside of the tensile material 2 through the gap between the tensile materials 2 and 2 and is pulled. Since it adheres to almost the entire outer peripheral surface of the material 2, almost the entire outer peripheral surface of the tension material becomes an adhesion surface with the hardened material, and when obtaining the same tensile force, the minimum cross-sectional area is sufficient. Properties and construction costs can be improved.

FIG. 8 shows the situation when the hardening material B is broken.
In this breaking state, as the wedge portion 6a advances, the sheath 3 of the core material 1 is broken along the breaking portion 7, and
The surrounding tensile members 2... And the hardening material B are pushed outward by the wedge effect, and the hardening material B is destroyed by the outward pushing and spreading.

After the core material 1 is pulled out, the hardening material B
Is released from the adhesion of the tension member 2 to the hardening material B, and the pull member 2 can be pulled out and collected.

[0025]

According to the removal anchor of the present invention, since the core member has the sheath, and the sheath functions to hold the core member free from the hardened material, a free cross-sectional shape is used as the tension member. Can be used, for example, a steel stranded wire that can be obtained at low cost as a commercial product can be used, so material costs are low,
In addition, since the steel stranded wire has flexibility, it can be easily carried into the construction site and handled when constructing the anchor, and almost the entire outer peripheral surface of the pulling material can be used as an adhesion surface with the hardening material, The outer peripheral surface and the cross-sectional area of the tension member are not wasted, and the workability and the construction cost can be improved.

Furthermore, since the sheath of the core can be left in the hardened material as a withdrawal residue during the operation of extracting the core with substantially no wrinkles, the sheath may cause an increase in the core material withdrawal resistance. The removal of the core material and the breakage of the hardened material can be performed stably and reliably, and a removal anchor with good quality performance can be provided.

[Brief description of the drawings]

FIG. 1 is an explanatory view schematically showing a fixing state of a removal anchor of the present invention.

FIG. 2 is a longitudinal sectional view of the removal anchor of the present invention.

FIG. 3 is a sectional view of a fixing unit.

FIG. 4 is a cross-sectional view of the free length portion.

FIG. 5 is a partially enlarged longitudinal sectional view showing a situation where a wedge portion is inserted into a sheath protruding portion.

FIG. 6 is a partially enlarged longitudinal sectional view showing a state at the time of a breaking operation of a hardening material.

FIG. 7 is a partially enlarged cross-sectional view showing a state before a hardened material is broken.

FIG. 8 is a partially enlarged cross-sectional view showing a situation after the hardened material is broken.

FIG. 9 is a longitudinal sectional view schematically showing a fixing state of a conventional removal anchor.

FIG. 10 is a longitudinal sectional view schematically showing a state of destruction of a hardened material.

FIG. 11 is an enlarged transverse sectional view of the same.

[Explanation of symbols]

 A Removal anchor of the present invention B Hardened material C Drilling hole 1 Core material 2 Pulling material 3 Sheath 4 Sheath 5 Lubricant 6 Expansion tool 6a Wedge part 7 Breaking part 8 Protective cap

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masaaki Ohinata 3-3-20 Kikyogaoka Minami, Nabari City, Mie Prefecture (72) Inventor Hirohisa Tanimuro 448-5 Hagiwaracho, Ikoma City, Nara Prefecture (56) References Special JP-A-58-195622 (JP, A) JP-A-9-41371 (JP, A) JP-B-55-21849 (JP, B2) JP-B-56-11007 (JP, B2) JP-B-7-47849 ( JP, B2) (58) Field surveyed (Int. Cl. ⁶ , DB name) E02D 5/80

Claims (3)

(57) [Claims] In a state where an anchor is constructed, a core material is extracted toward the ground together with an expansion tool fixed to a tip portion, and a plurality of tension members disposed around the core material are extracted outward as the core material is extracted. In a removal anchor that expands and breaks the hardened material around the tension material, the core material is sheathed over its entire length, while the tension material disposed around the core material is made of steel strands. The core material has a distal end bare portion protruding distally from the tension member, and an extension device having a tapered cone-shaped wedge portion on the distal end bare portion is provided, and the wedge portion of the extension device is a sheath. gradient are inserted in advance into the sheath at the lower end side, the sheath of the core material, extending axially facing the
A removal anchor, wherein a long break is formed . 2. The removal anchor according to claim 1, wherein a lubricant is filled in the sheath of the core material. 3. The taper angle of the wedge portion of the expansion device is 2 to 10 °.
4. The method according to claim 1, wherein the distance is set within a range.
The removal anchor according to any one of the above.