Internal Fixer For Anchor Having Releasable Tensioning Steel Wire

Abstract

The present invention provides an internal fixer for an anchor having a releasable tensioning steel wire. The internal fixer of the present invention includes a first outer body (10), which is provided with a tube coupling hole (11), a body seating hole (13) and a wedge receiving body support means; and a wedge receiving body (30), which is seated in the body seating hole (13) and has a conical wedge seating hole (31), into which separated wedge bodies (41) are seated. The internal fixer further includes a wedge unit (40), which is seated in the wedge seating hole (31) of the wedge receiving body (30) and comprises the three separated wedge bodies (41); and a second outer body (20), which supports and covers both the wedge receiving body (30), which is seated in the body seating hole (13), and the wedge unit (40), which is placed in the wedge seating hole (31).

Description

TECHNICAL FIELD

The present invention relates, in general, to internal fixers for anchors having releasable tensioning steel wires and, more particularly, to an internal fixer for an anchor having a releasable tensioning steel wire in which, when the tensioning steel wire is tensioned, a wedge receiving body along with separated wedge bodies is moved in the direction in which the tensioning steel wire is tensioned, and is fastened, so that the space required for movement of a wedge unit when the tensile force is removed is ensured, and in which only the separated wedge bodies are moved backwards by repulsive force generated when the tensile force is removing from the tensioning steel wire in the fixed state of the wedge receiving body, or by both the force of striking the tensioning steel wire inwards and the restoring force of a spring, and they are separated in the diameter direction, so that the tensioning steel wire can be easily and reliably removed.

BACKGROUND ART

Generally, ground anchors are used in engineering work such as bracing work and engineering work for stabilizing a tunnel portal or for reinforcing a stone wall or a retaining wall. For construction of a ground anchor, a hole is bored at a desired position in soft ground using a boring machine, and a grout hose and a load-carrying body, which includes the tensioning steel wire and the internal fixer, are inserted into the boring hole, before grout is injected through the grout hose. After the injected grout cures with the load-carrying body, an external fixer is coupled to the other end of the tensioning steel wire. Thereafter, the tensioning steel wire is pulled by a tensioning machine, so that the grout and ground are tensioned, thus reinforcing the soft ground.

Such a ground anchor has advantages of efficient construction management when working in urban areas and reduction in construction period. However, in the case that other engineering work is being conducted adjacent to the area in which the ground anchor is installed, because the tensioning steel wire has six times the strength of a typical steel wire per unit area, an excavator and a boring machine may be damaged, and the construction period may be increased. To solve the above-mentioned problem, a ground anchor, which has a structure such that a tensioning steel wire is removable depending on the construction process after excavation work has been completed, was developed.

Various internal fixers for anchors having releasable tensioning steel wires have been proposed. Of them, two will be explained herein below. First, in a technique proposed in Korean Patent Registration No. 10-0447967, which was filed by the inventor of the present invention, a wedge unit is elastically supported by a spring in a wedge unit installation space of an anchor body, and a tensioning steel wire is inserted into and held by the wedge unit. In this technique, a process, in which the tensioning steel wire is instantaneously moved backwards and released by striking a strand or strands of the tensioning steel wire and, simultaneously, after the strand of the tensioning steel wire is inserted, the tensioning steel wire is held while the wedge unit is inserted into the wedge unit installation space by the elasticity of the spring, is repeated several times. Thus, at the moment at which an end of the tensioning steel wire other than the struck strand escapes from the wedge unit, the tensioning steel wire is released. Thereafter, the tensioning steel wire is pulled out, thus being removed.

Furthermore, in an internal fixer for an anchor having a releasable tensioning steel wire in Korean Utility Model Registration No. 20-0309952, a tensioning steel wire is inserted into a main body until it reaches separated wedge bodies and a repulsive force transmission cap through a coned disc spring and a wedge receiving body.

Furthermore, an elastic spring, which is provided on the upper end of the repulsive force transmission cap, is locked to a support stop of a cover cap. The wedge receiving body is elastically installed in the main body. The separated wedge bodies are seated in the wedge receiving body.

In the internal fixer of the above Korean Utility Model having the above-mentioned construction, when the tensioning steel wire is tensioned, the repulsive force transmission cap and the wedge receiving body, which are coupled to the separated wedge bodies, are moved along with the separated wedge bodies in the direction in which the tensioning steel wire is tensioned, and the coned disc spring is compressed. Thereafter, when the tensioning steel wire is cut, the repulsive force transmission cap and the separated wedge bodies are moved by the repulsive force. Then, the elastic spring of the repulsive force transmission cap is locked to a locking groove of the cover cap. At this position, because the separated wedge bodies are in a state of being slightly removed from the wedge receiving body, the separated wedge bodies are separated in the diameter direction, so that the tensioning steel wire may be removed by pulling.

DISCLOSURE OF INVENTION

Technical Problem

In the internal fixer disclosed in Korean Patent Registration No. 10-0447967, which was filed by the inventor of the present invention, because the tensioning steel wire is pushed out and removed by striking and inserting a strand and strands of the tensioning steel wire, the tensioning steel wire can be reliably removed even if the anchor head, which is the internal fixer, rusts due to water that permeates the anchor head. However, because the number of times a strand of the tensioning steel wire must be struck typically reaches several tens of times, work efficiency is reduced. As well, there is a problem in that, since physical fatigue increases as the work progresses, a worker may fail to carry out the work.

Meanwhile, in the internal fixer disclosed in Korean Utility Model Registration No. 20-0309952, the repulsive force transmission cap and the separated wedge bodies are moved by repulsive force generated when cutting the tensioning steel wire, thereby the wedge receiving body is moved in the same direction. Therefore, expansion of the separated wedge bodies is unreliable. To solve this, the length of the main body is increased, and thus there is a problem of increased material cost.

In particular, because a process of cutting the tensioning steel wire is typically conducted using an oxygen cutting machine, the strands of the tensioning steel wire are consecutively cut one by one or in groups of two, but not all at the same time. Thus, the repulsive force of the tensioning steel wire is generated slowly. Therefore, this repulsive force may not be enough for the elastic spring, which is provided on the upper end of the repulsive force transmission cap, to reach the locking groove of the cover cap. In this case, the elastic spring, which is provided on the upper end of the repulsive force transmission cap, is not locked to the locking groove of the cover cap, so that the separated wedge bodies remain in the wedge receiving body without expanding in diameter. As a result, the tensioning steel wire might not be removed.

Technical Solution

Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and objects of the present invention will be presented herein below.

A first object of the present invention is to provide an internal fixer for an anchor having a releasable tensioning steel wire in which, when the tensioning steel wire is tensioned after the internal fixer is installed in the ground, a wedge receiving body along with a wedge unit is moved in the direction in which the tensioning steel wire is tensioned, and is fastened, so that the space required for movement of a wedge unit when the tensile force is removed is reliably ensured, and in which only the separated wedge bodies are moved backwards by repulsive force generated when removing the tensile force from the tensioning steel wire when the wedge receiving body is in a fixed state, or by the force of striking the tensioning steel wire inwards, and they are expanded in diameter, so that the tensioning steel wire can be easily and reliably removed.

A second object of the present invention is to provide an internal fixer in which a wedge returning member is additionally provided at a lower position in a body receiving hole of a first outer body, so that, when the tensioning steel wire is cut to remove it after having been tensioned, the wedge returning member pushes the wedge unit backwards from the wedge seating hole of the wedge receiving body, thus the separated wedge bodies of the wedge unit are separated in the diameter direction, thereby the tensioning steel wire is easily released.

A third object of the present invention is to provide an internal fixer, in which, when the tensioning steel wire is inserted into the internal fixer, the separated wedge bodies are pushed backwards from the wedge seating hole of the wedge receiving body and expand in diameter, so that the end of the tensioning steel wire is inserted into the separated wedge bodies and, thereafter, when the force that has been applied to the tensioning steel wire is removed, the separated wedge bodies are inserted into the wedge seating hole of the wedge receiving body by the restoring force of the elastic support member, so that the tensioning steel wire can be easily held by the wedge unit, that is, the assembly of the tensioning steel wire can be easily realized merely by inserting and releasing the tensioning steel wire.

A fourth object of the present invention is to provide an internal fixer in which a cap member, which protrudes from the upper end of the wedge unit, is provided, so that, because the elastic support member is seated onto the wedge unit and is fitted over the outer surface of the cap member, operational precision is ensured and the elastic support member does not become misaligned or undesirably move, and, as well, the end of the tensioning steel wire, which is inserted through a tube coupling hole of the first outer body, is inserted into the cap member via the separated wedge bodies, so that the tensioning steel wire is reliably held by the separated wedge bodies, and, as the separated wedge bodies hold the tensioning steel wire more strongly, the part of the tensioning steel wire that is in the cap member becomes untwisted, thus the diameter of that part of the tensioning steel wire is slightly increased, thereby the tensioning steel wire can be more securely held, as if a stop protrusion were formed on the tensioning steel wire.

A fifth object of the present invention is to provide an internal fixer in which the elastic support member and the wedge returning member respectively comprise a compression coil spring which is fitted over the cap member protruding from the upper end of the wedge unit, and a compression coil spring which supports the lower end of the separated wedge bodies of the wedge unit, so that the number of elements is minimized, thus reducing the manufacturing cost, and enhancing workability.

Advantageous Effect

In the internal fixer for an anchor having a releasable tensioning steel wire according to the present invention, when the tensioning steel wire is tensioned after the internal fixer has been installed in the ground, a wedge receiving body along with a wedge unit is moved in the direction, in which the tensioning steel wire is tensioned, and is fastened, so that the space required for movement of a wedge unit when the tensile force is removed is reliably ensured. Furthermore, only the separated wedge bodies are moved backwards and expanded in diameter by repulsive force generated when the tensile force of the tensioning steel wire is removed when the wedge receiving body is in a fixed state, or by the force of striking the tensioning steel wire inwards, so that the tensioning steel wire can be easily and reliably removed.

As well, a wedge returning member is additionally provided at a lower position in a body receiving hole of a first outer body, so that, when the tensioning steel wire is cut to remove it after having been tensioned, the wedge returning member pushes the wedge unit backwards from the wedge seating hole of the wedge receiving body, thus the separated wedge bodies of the wedge unit are separated in a diameter direction, thereby the tensioning steel wire is easily released.

In addition, when the tensioning steel wire is inserted into the internal fixer, the separated wedge bodies are pushed backwards from the wedge seating hole of the wedge receiving body and expanded in diameter, so that the end of the tensioning steel wire is inserted into the separated wedge bodies and, thereafter, when the force that has been applied to the tensioning steel wire is removed, the separated wedge bodies are inserted into the wedge seating hole of the wedge receiving body by the restoring force of the elastic support member, so that the tensioning steel wire can be easily held by the wedge unit. In other words, the assembly of the tensioning steel wire can be easily realized merely by inserting and releasing the tensioning steel wire.

Moreover, a cap member, which protrudes from the upper end of the wedge unit, is provided, so that, because the elastic support member is seated onto the wedge unit and fitted over the outer surface of the cap member, operational precision is ensured and the elastic support member does not become misaligned or undesirably move. As well, the end of the tensioning steel wire, which is inserted through a tube coupling hole of the first outer body, is inserted into the cap member via the separated wedge bodies, so that the tensioning steel wire is reliably held by the separated wedge bodies, and, as the separated wedge bodies hold the tensioning steel wire more strongly, the part of the tensioning steel wire that is in the cap member becomes untwisted, thus the diameter of that part of the tensioning steel wire is slightly increased, thereby the tensioning steel wire can be held more securely, as if a stop protrusion were formed on the tensioning steel wire.

Finally, the elastic support member and the wedge returning member respectively comprise a compression coil spring, which is fitted over the cap member protruding from the upper end of the wedge unit, and a compression coil spring, which supports the lower end of the separated wedge bodies of the wedge unit, so that the number of elements is minimized, thus reducing the manufacturing cost and enhancing workability.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view showing an internal fixer for an anchor having a releasable tensioning steel wire, according to an embodiment of the present invention;

FIG. 2 is an exploded perspective view of FIG. 1;

FIG. 3 is a sectional view showing the tensioning steel wire in a state of being tensioned in the internal fixer according to the present invention;

FIG. 4 is a sectional view showing the tensioning steel wire released from a wedge unit in the internal fixer according to the present invention;

FIGS. 5 through 11 are views showing embodiments of a wedge receiving body support means of the internal fixer according to the present invention;

FIG. 12 is a sectional view showing an internal fixer for an anchor having a releasable tensioning steel wire, a wedge returning means being provided for a wedge unit, according to another embodiment of the present invention;

FIGS. 13 through 15 are views illustrating processes in which the tensioning steel wire is held by the internal fixer, tensioned, and released from the internal fixer according to present invention;

FIG. 16 is a sectional view showing an internal fixer for an anchor having a releasable tensioning steel wire, a wedge returning means being provided in a wedge unit, according to another embodiment of the present invention; and

FIGS. 17 through 19 are views showing internal fixers for anchors having releasable tensioning steel wires, a wedge support means being provided in wedge units, according to another embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

In order to accomplish the above objects, the present invention provides an internal fixer for an anchor having a releasable tensioning steel wire, including: a first outer body, with a tube coupling hole and a body seating hole coaxially formed in the first outer body so that the tensioning steel wire passes therethrough, and a wedge receiving body support means provided on an inner surface of the body seating hole; a wedge receiving body seated by the wedge receiving body support means in the body seating hole and having a conical wedge seating hole, into which separated wedge bodies are seated; a wedge unit seated into the wedge seating hole of the wedge receiving body and comprising the three separated wedge bodies, which are arranged in a cone shape to hold the tensioning steel wire; and a second outer body supporting and covering the wedge receiving body, which is seated in the body seating hole of the first outer body, and the wedge unit, which is placed in the wedge seating hole of the wedge receiving body.

The second outer body has a shape such that it supports and covers the wedge receiving body, which is seated in the body seating hole of the first outer body, and an elastic support member is provided in the second outer body and elastically supports, pushes and seats the wedge unit, which is placed in the wedge seating hole of the wedge receiving body, into the wedge seating hole.

In the internal fixer for the anchor having the releasable tensioning steel wire according to the present invention, it is sufficient if the wedge receiving body support means of the first outer body has a structure such that, when tensile force is applied to the tensioning steel wire, the wedge receiving body is advanced along with the wedge unit and fastened to the bottom of the body seating hole.

The wedge receiving body support means may comprise a support protrusion, which protrudes from the inner surface of the body seating hole. The support protrusion may have a ring shape, which is formed around the entire circumference of the body seating hole, or, alternatively, may comprise a plurality of support protrusions, which are spaced apart from each other. The support protrusion may have various shapes, such as a rounded cross-section, a rectangular cross-section or a trapezoidal cross-section.

Furthermore, the wedge receiving body support means may be realized by a tapered inner surface of the body seating hole which is reduced in diameter from a deep portion thereof to a shallow portion thereof.

The wedge receiving body support means may comprise at least one support O-ring or expandable C-shaped metal ring, which is provided in a ring groove formed in the inner surface of the body seating hole, such that, when the wedge receiving body is advanced by the tensioning steel wire, it comes into close contact with and holds the outer surface of the wedge receiving body. In the case that the C-shaped metal ring is used, a ring stop groove may be formed in the inner surface of the wedge seating groove, so that, when the wedge receiving body is advanced by the tensioning steel sire, the C-shaped metal ring is locked to the ring stop groove.

As well, a C-shaped metal ring may be provided on the outer surface of the wedge receiving body. In this case, a ring stop groove is formed in the inner surface of the body seating hole.

The internal fixer for the anchor having the releasable tensioning steel wire according to the present invention may further include a wedge returning member, which is provided in the body seating hole of the first outer body, so that, when the wedge receiving body along with the wedge unit is advanced and fastened to the body seating hole, the wedge unit, which is placed in the wedge seating hole of the wedge receiving body, is biased backwards by the wedge returning member.

The wedge returning member suffices as a compression coil spring. A ring member, which has a flange on an end thereof, may be provided on an end of the wedge returning member to support lower ends of the separated wedge bodies.

The wedge returning member may comprise a spring seating hole, which is formed in the bottom of the body seating hole for installation of the wedge returning member, and a support protrusion, which is provided on the bottom of the spring seating hole to hold the end of the wedge returning member.

In the internal fixer for the anchor having the releasable tensioning steel wire according to the present invention, the elastic support member may be provided in the second outer body to elastically push and seat the wedge unit into the wedge seating hole of the wedge receiving body. The elastic support member suffices as a compression coil spring. A cap member may be provided in an inner ring groove, which is formed in upper ends of the separated wedge bodies constituting the wedge unit, so that an elastic support member is fitted over the cap member and the tensioning steel wire is more deeply inserted into the cap member.

Furthermore, a compression cover may be provided on the separated wedge bodies outside the cap member between the separated wedge bodies and the elastic support member to ensure reliable expansion of the separated wedge bodies.

MODE FOR THE INVENTION

Hereinafter, an internal fixer for an anchor having a releasable tensioning steel wire according to the present invention will be described in detail with reference to the attached drawings.

FIG. 1 is a sectional view showing the internal fixer for the anchor having the releasable tensioning steel wire, according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of FIG. 1.

As shown in the drawings, in the internal fixer for the anchor having the releasable tensioning steel wire according to the present invention, a wedge receiving body 30 is installed in first and second outer bodies 10 and 20, and a wedge unit 40 is inserted into the wedge receiving body 30 and is supported by the second outer body 20 such that the wedge unit 40 is prevented from being undesirably removed from the wedge receiving body 30. The wedge unit 40 has a structure such that, when the releasable tensioning steel wire 30 is inserted into the wedge unit 40 through a tube coupling hole 11 of the first outer body 10, the wedge unit 40 holds the tensioning steel wire 30. Typically, the tensioning steel wire 30 comprises seven strands of steel wires, in which six strands of steel wires are twisted around a center steel wire at a regular pitch.

The first outer body 10 has the tube coupling hole 11, through which the tensioning steel wire 30 is inserted, and a body seating hole 13, which is coaxially formed therein, and in which the wedge receiving body 30 is seated. Furthermore, a support protrusion 13a, which is a means for supporting the wedge receiving body 30, is provided on the circumferential inner surface of the body seating hole 13, so that, while no tension is applied to the tensioning steel wire 50, the wedge receiving body 30 is seated at a rear position of the first outer body 10 and is supported by both the support protrusion 13a and the second outer body 20, and, when tensile force for pulling the tensioning steel wire 50 is applied to the tensioning steel wire 50 after the internal fixer has been installed in the ground, the support protrusion 13a allows the wedge receiving body 30 along with the wedge unit 40 to be moved towards the tube coupling hole 11 (that is, to advance forwards).

Preferably, the support protrusion 13a protrudes from the inner surface of the body seating hole 13 to a height ranging from 0.1 mm to 0.5 mm. The reason why the height of the support protrusion 13a is limited is that, if the protruding height is less than 0.1 mm, the support protrusion 13a may be easily destroyed even by a relatively weak tensioning load applied to the tensioning steel wire 50, and thus the support protrusion 13a cannot conduct its intended function, and, conversely, if the height to which the support protrusion 13a protrudes is 0.5 mm or more, because a very large outer force is required to destroy the support protrusion 13a, a tensioning machine having a large capacity is required and, as well, when the wedge receiving body 30 is advanced, a large impact is applied to the first outer body 10, and this impact may have a bad influence on the internal fixer.

In this embodiment, the support protrusion 13a, which protrudes throughout the entire circumference of the circumferential inner surface of the body seating hole 13 to have a ring shape and to form an angled and stepped part, is used as the wedge receiving body support means. Furthermore, the support protrusion 13a may have a rounded cross-section, a rectangular cross-section or a trapezoidal cross-section. As well, a plurality of support protrusions, which are spaced apart from each other on the circumferential inner surface of the body seating hole 13, may be used as the wedge receiving body support means. In addition, the wedge receiving body support means may be realized by a support protrusion that has two or more steps. In particular, as shown in FIG. 5, the wedge receiving body support means may be realized by a tapered inner surface of the body seating hole 13 which is reduced in diameter from the rear portion to the front portion.

In addition, the wedge receiving body support means may be provided only on the circumferential inner surface of the body seating hole, or, alternatively, may be provided in a combined manner both on the wedge receiving body and on the circumferential inner surface of the body seating hole. Hereinafter, examples thereof will be described.

FIG. 16 shows at least one support O-ring 14, which is provided in a ring seating groove 13b in the circumferential inner surface of a body seating hole 13 so that, when a wedge receiving body 30 is advanced by pulling the tensioning steel wire 60, the support O-ring 14, which has supported one end of the wedge receiving body 30, comes into close contact with and holds the circumferential outer surface of the wedge receiving body 30.

FIGS. 7 and 8 show a C-shaped metal ring 15, which elastically expands in diameter and is provided in a ring seating groove 13b in the circumferential inner surface of a body seating hole 13 so that, when a wedge receiving body 30 is advanced by pulling the tensioning steel wire 60, the C-shaped metal ring 15, which has supported an end of the wedge receiving body 30, holds the circumferential outer surface of the wedge receiving body 30.

FIGS. 9 and 10 show a C-shaped metal ring 15, which elastically expands in diameter and in the circumferential inner surface of a body seating hole 13 to temporarily support the end of a wedge receiving body 30, and show a ring stop groove 32, which is formed in the circumferential outer surface of the wedge receiving body 30 such that, when the wedge receiving body 30 is pulled out by the tensioning steel wire 50, the metal ring 15 is locked to the ring stop groove 32.

Furthermore, as shown in FIG. 11, the C-shaped metal ring 15 may be provided in a ring seating groove 33 formed in the circumferential outer surface of a wedge receiving body 30. In this case, a ring stop groove 13c must be formed in the circumferential inner surface of a body seating hole 13.

As such, in the case that the C-shaped metal ring 15 is used as the wedge receiving body support means, it suffices if the C-shaped metal ring 15 has a circular or other cross-section, as long as the outer surface or inner surface thereof is rounded.

Meanwhile, a conical wedge seating hole 31, into which the wedge unit 40 is seated, is formed in the wedge receiving body 30. The wedge seating hole 31 has a diameter greater than the diameter of lower ends of separated wedge bodies 41 of the wedge unit 40, such that, when the separated wedge bodies 41 are seated in the wedge seating hole 31, the lower ends thereof protrude outside the wedge seating hole 31.

Furthermore, the edge of the lower end of the wedge receiving body 30 that contacts the wedge receiving body support means is preferably rounded or chamfered, such that, when the tensioning steel wire 50 is tensioned, the wedge receiving body 30 elastically expands or plastically deforms a single wedge receiving body support means, which is provided on the inner surface of the body seating hole 13, or a wedge receiving body support means, which is provided in a combined manner on the body seating hole 13 and the wedge receiving body 30, so that the wedge receiving body 30 can be easily moved to the bottom of the body seating hole 13. As well, preferably, the wedge receiving body 30 is made of material that is processed by heat treatment or has stiffness higher than that of the first outer body 10.

The wedge unit 40 is seated in the wedge seating hole 31 of the wedge receiving body 30. The wedge unit 40 includes the three separated wedge bodies 41, which are disposed in a circular arrangement and form a cone shape having a first hole 42, through which the tensioning steel wire 50 is inserted. Furthermore, an O-ring 43, which serves to prevent the three separate wedge bodies 41 from being removed and to expand the diameter of lower ends of the three separate wedge bodies 41, is fitted over circumferential outer surfaces of upper ends of the three separate wedge bodies 41, so that they form a single unit. As well, the upper ends of the three separate wedge bodies 41 are closed such that the tensioning steel wire 50 is stopped by the upper ends without passing therethrough and the lower ends of the three separate wedge bodies 41 are expanded in diameter by the O-ring 43.

The first hole 42 of the wedge unit 40 has an uneven inner surface, which has a sawtooth or spiral shape. Therefore, when the tensioning steel wire 50 is tensioned, the uneven inner surface of the first hole 42 serves to prevent the tensioning steel wire 50 from slipping or being undesirably removed.

It is sufficient for the second outer body 20 to have a structure such that the wedge receiving body 30, which is seated in the body seating hole 13 of the first outer body 10, and the wedge unit 40, which is seated into the wedge seating hole 31 of the wedge receiving body 30, can be securely supported without undesirably moving.

A steel wire tube 51 is watertightly fitted into the tube coupling hole 11 of the first outer body 10 without being damaged at an end thereof such that it does not interfere with insertion of the tensioning steel wire 50 into the first outer body 10. As well, the steel wire tube 51 is finished with resin having superior toughness to prevent it from breaking due to a drop in temperature, so that it can be used even in the winter. Furthermore, the steel wire tube 51 prevents water from entering the internal fixer, thus preventing elements of the internal fixer from rusting.

The watertight structure of the steel wire tube 51 includes a reinforcing member 52, which is fitted into the end of the steel wire tube 51 inserted into the tube coupling hole 11 of the first outer body 10, and a conical watertight packing member 53, which is fitted over the end of the steel wire tube 51, into which the reinforcing member 52 is fitted, and is forcibly fitted into the tube coupling hole 11 of the first outer body 10.

Even if the watertight packing member 53 is press-fitted or struck in a direction from the outside of the steel wire tube 51, which is inserted into the lower end of the first outer body 10, towards the center line of the steel wire tube 51, the watertight packing member 53 must not be broken, but must merely be inserted while being plastically deformed. Therefore, the watertight packing member 53 is preferably made of soft resin having superior ductility and toughness.

The reinforcing member 52 must be able to prevent a contraction phenomenon of the steel wire tube 51 in which it is reduced in diameter by deformation thereof during a process of forcibly fitting the watertight packing member 53 into the lower end of the first outer body 10 using the compressing force of plastic deformation. To achieve the above-mentioned purpose, it is preferable that the reinforcing member 52 be made of metal or high stiffness material, such as compressed fiber and high stiffness resin.

The assembly of the internal fixer of the present invention having the above-mentioned construction will be explained herein below. The steel wire tube 51 is first inserted into and coupled to the tube coupling hole 11 of the first outer body 10. Here, after the reinforcing member 52 has been fitted into the end of the steel wire tube 51 and the conical watertight packing member 53 has been fitted over the end of the steel wire tube 51, the end of the steel wire tube 51 is inserted into the tube coupling hole 11 of the first outer body 10. Thereafter, the watertight packing member 53 is press-fitted into the tube coupling hole 11. Then, the steel wire tube 51 is securely watertightly fitted into and coupled to the first outer body 10 without being damaged at the end thereof.

In this state, the tensioning steel wire 50 is inserted into the steel wire tube 51, such that the end thereof passes through the body seating hole 13 of the first outer body 10 and passes through and protrudes outside the wedge receiving body 30, which is temporarily seated in the body seating hole 13. Subsequently, the end of the tensioning steel wire 50 is maximally inserted into the first hole 42 in the wedge unit 40, which is constructed by assembling the three separated wedge bodies 41 with each other using the O-ring 43 such that they are separated in the diameter direction at the lower ends thereof by the O-ring 43. Thereafter, in the state in which the separated wedge bodies 41 are closed to hold the tensioning steel wire 50, the wedge unit 40 is inserted into the wedge seating hole 31 of the wedge receiving body 30 and, thereafter, the second outer body 20 is coupled to the first outer body 10.

When the second outer body 20 is coupled to the first outer body 10, the second outer body 20 pushes the wedge receiving body 30 and the separated wedge bodies 41 of the wedge unit 40, which is placed in the wedge seating hole 31 of the wedge receiving body 30. Therefore, the wedge receiving body 30 is seated onto the support protrusion 13a of the wedge receiving body support means, and the tensioning steel wire 50 is held by the separated wedge bodies 41 more securely.

The internal fixer, which has been assembled through the above-mentioned process, is installed in the ground. First, a braced wall is constructed to prevent a cut slope, such as a retaining wall, requiring ground reinforcement, from collapsing. In consideration of the ground reinforcement using anchors, holes are bored downwards at an incline in the ground to predetermined depths using a boring machine at positions spaced apart from each other at regular intervals. Thereafter, a grout hose and a load-carrying body, which includes the tensioning steel wire and the internal fixer, are inserted into each boring hole, and grout is injected through the grout hose. After the injected grout cures with the load-carrying body, an external fixer is coupled to the other end of the tensioning steel wire, which is adjacent to the braced wall.

In this state, the tensioning steel wire is pulled by a tensioning machine, so that the grout and ground are tensioned, thus reinforcing the soft ground. This will be explained in detail with reference to FIGS. 1 and 3.

When the tensioning steel wire is pulled at a position adjacent to the braced wall, the tensile force of the tensioning machine is transmitted to the wedge receiving body 30 through the wedge unit 40. Thus, the wedge receiving body 30 along with the wedge unit 40 is advanced after breaking the support protrusion 13a, which is provided on the inner surface of the body seating hole 13 of the first outer body 10, until the wedge receiving body 30 reaches the bottom of the body seating hole 13 of the first outer body 10, that is, until it changes from the state of FIG. 1 to that of FIG. 3. At this time, because the wedge unit 40 is in a state of being tensioned by the tensioning steel wire 50, the wedge receiving body 30 maintains the state of being seated in the wedge seating hole 31. Therefore, the separated wedge bodies 41 of the wedge unit 40 reliably hold the tensioning steel wire 50.

As such, when the wedge receiving body 30 is advanced until it reaches the bottom of the body seating hole 13 of the first outer body 10, the wedge receiving body 30 is securely fastened to the body seating hole 13 of the first outer body 10 by the broken support protrusion 13a, which has been provided on the inner surface of the body seating hole 13 of the first outer body 10, as if it were processed by being integrated or press-fit.

Continuously, as the tensioning machine more strongly pulls the tensioning steel wire 50, increased tensile force is applied to the grout, the ground and the tensioning steel wire 50. Meanwhile, after the ground reinforcing work has been completed, the tensioning steel wire 50 must be removed.

In the process of removing the tensioning steel wire 50, the part of the tensioning steel wire 50 exposed outside at a side adjacent to the braced wall is first cut using an oxygen cutting machine to remove the tensile force, which has been applied to the tensioning steel wire 50. At this time, in the state in which the wedge receiving body 30 is fastened in the body seating hole 13 of the first outer body 10, the wedge unit 40 may be slightly moved backwards by repulsive force generated when removing the tensile force from the tensioning steel wire 50.

Thereafter, the cut end of the tensioning steel wire 50, part of which is installed in the ground, is struck with a hammer one or two times. Then, as shown in FIG. 4, only the wedge unit 40 is moved backwards by the force of striking the tensioning steel wire 50, and the separated wedge bodies 41 are separated in the diameter direction by the O-ring 43. Therefore, the tensioning steel wire 50 is released from the separated wedge bodies 41 of the wedge unit 40.

As such, the reason why the wedge unit 40 can be moved backwards is that, when the tensioning steel wire 50 is tensioned, a space is defined behind the wedge unit 40 by movement of the wedge receiving body 30 and the wedge unit 40 to the bottom of the body seating hole 13 of the first outer body 10.

As such, after the tensioning steel wire 50 has been released from the wedge unit 40, because the only resistance is its own weight and a little frictional resistance, the tensioning steel wire 50 can be easily removed by pulling it.

FIG. 12 is a sectional view showing an internal fixer for an anchor having a releasable tensioning steel wire, a wedge returning means being provided for a wedge unit, according to another embodiment of the present invention. In the wedge returning means, a spring seating hole 17 is formed in the bottom of a body seating hole 13 of a first outer body 10, and a wedge returning member 60 is provided in the spring seating hole 17, such that, when the tensioning steel wire 60 is tensioned so that a wedge receiving body 30 is advanced into and fastened into a body seating hole 13, ends of separated wedge bodies 41 of the wedge unit 40 which protrude from the wedge seating hole 31 of the wedge receiving body 30 are biased backwards by the wedge returning member 60.

The wedge returning member 60 is not limited to any particular structure, so long as it can push the end of the wedge unit 40 backwards and can be inserted into the wedge seating hole 31 of the wedge receiving body 30. Preferably, a compression coil spring is used as the wedge returning member 60. The shape of the compression coil spring may be changed depending on the size of the spring seating hole 17.

For example, in the case that the diameter of the spring seating hole 17 is about twice that of the tensioning steel wire, it is preferable that a conical compression coil spring be used. In the case that the spring seating hole 17 has a relatively small diameter similar to that of the wedge seating hole 31, it is preferable that a cylindrical compression coil spring be used.

As described above, in the case that the wedge returning member 60 is provided in the internal fixer of the present invention, in a process of removing the tensioning steel wire 50 after the ground reinforcing work has been completed, when the part of the tensioning steel wire 50 that is exposed outside at the side adjacent to the braced wall is cut using an oxygen cutting machine to remove the tensile force, which has been applied to the tensioning steel wire 50, the wedge unit 40 is easily moved backwards both by repulsive force, which is generated upon removal of the tensile force of the tensioning steel wire 50 in the state in which the wedge receiving body 30 is fastened in the body seating hole 13 of the first outer body 10, and by restoring force of the compression coil spring, which is the wedge returning member 60, as shown from FIG. 13 to FIG. 14.

Here, even if the wedge unit 40 is not moved backwards for some reason such as corrosion of the wedge receiving body 30 and the wedge unit 40, when the cut end of the tensioning steel wire 50, part of which is installed in the ground, is struck with a hammer one or two times, as shown in FIG. 15, the wedge unit 40 can be moved backwards both by the force of striking the tensioning steel wire 50 and by the restoring force of the compression coil spring, which is the wedge returning member 60.

As such, when the wedge unit 40 is moved backwards so that the separated wedge bodies 41 are separated in the diameter direction by an O-ring 43, the tensioning steel wire 50 is released from the separated wedge bodies 41 of the wedge unit 40. Therefore, the tensioning steel wire 50 can be easily removed by pulling it.

Meanwhile, as shown in FIG. 16, the wedge returning member 60 may consist of a support ring member 61, which supports the ends of the separated wedge bodies 41 and has a flange on an end thereof, and a compression coil spring 62, which has a cylindrical shape and pushes the support ring member 41 backwards.

FIG. 17 illustrates an internal fixer for an anchor having a releasable tensioning steel wire, a wedge support means being provided for a wedge unit, according to another embodiment of the present invention. In this embodiment, the second outer body 20 has a length sufficient to define a space for ensuring backward movement of a wedge unit 40. An elastic support member 70, which pushes and seats the wedge unit 40 into a wedge seating hole 31 of a wedge receiving body 30, is installed in the space defined in the second outer body 20. The elastic support member 70 is not limited to any particular structure, so long as it elastically and reliably supports the wedge unit 40. Preferably, a cylindrical or conical compression coil spring, which is freely available, is used as the elastic support member 70.

To assemble this embodiment having the above-mentioned construction, the wedge receiving body 30 along with the wedge unit 40 is seated into a body seating hole 13 of a first outer body 10. Thereafter, the second outer body 20 is coupled to the first outer body 10 after the elastic support member 70 has been installed in the second outer body 20. Then, the wedge unit 40 is elastically supported by the elastic support member 70.

Furthermore, to assemble the tensioning steel wire 50, the tensioning steel wire 50 is inserted into a steel wire tube 51, which is fitted into a tube coupling hole 11 of the first outer body 10. Then, the wedge unit 40 is moved backwards from the wedge receiving body 30 by the tensioning steel wire 50 in the state of being elastically supported by the elastic support member 70, so that the separated wedge bodies 41 of the wedge unit 40 are separated in the diameter direction by an O-ring 43 while an end of the tensioning steel wire 50 is inserted into the separated wedge bodies 41.

Thereafter, when force, which has been applied to the tensioning steel wire 50, is removed in the state in which the tensioning steel wire 50 is inserted into the separated wedge bodies 41, the separated wedge bodies 41 are inserted into the wedge seating hole 31 of the wedge receiving body 30 by the restoring force of the elastic support member 70. At this time, the tensioning steel wire 50 is reliably held by the separated wedge bodies 41. As such, the assembly of the tensioning steel wire 50 can be more easily conducted.

FIG. 18 illustrates an internal fixer for an anchor having a releasable tensioning steel wire, a wedge support means being provided for a wedge unit, according to another embodiment of the present invention. In this embodiment, an inner ring groove 43 is formed in an upper end of a first hole 42 defined by separated wedge bodies 41. A cap member 45, which is provided with a flange and has a cap-shaped cross-section, is coupled to the inner ring groove 43 and protrudes from the upper end of the first hole 42 without interfering with the diameter expanding motion of the separated wedge bodies 41. Even in this case, in which the cap member 45 protrudes from the upper end of the separated wedge bodies 41, an elastic support member 70, which pushes and seats the wedge unit 40 into a wedge seating hole 31 of a wedge receiving body 30, is provided in the second outer body 20. Although the wedge support means has been explained as having only a structure such that the cap member 45 is coupled to the inner ring groove 43 of the wedge unit 40, a circular plate may be additionally provided.

According to this embodiment having the above-mentioned construction, because the elastic support member 70, which comprises the cylindrical or conical compression coil spring, is seated onto the wedge unit 40 and fitted over the outer surface of the cap member 45, which protrudes from the wedge unit 40, operational precision is ensured without the elastic support member 70 being misaligned or undesirably moving.

Particularly, the end of the tensioning steel wire 50, which is inserted through a tube coupling hole 11 of the first outer body 10, is disposed in the cap member 45 via the separated wedge bodies 41. Thus, the tensioning steel wire 50 is reliably held by the separated wedge bodies 41. Furthermore, because the separated wedge bodies 41 hold the tensioning steel wire 50 more strongly, the tensioning steel wire 50, which is formed by twisting several wires, may be untwisted at a part thereof that is in the cap member 45, so that the diameter of that part of the tensioning steel wire 50 is slightly increased. Therefore, the tensioning steel wire 50 can be more securely held, as if a stop protrusion were formed on the tensioning steel wire 50.

Furthermore, as shown in FIG. 19, a compression cover 71 may is seated on the separated wedge bodies 41 outside the cap member 45 between the separated wedge bodies 41 and the elastic support member 70. The compression cover 71 prevents interference between the separated wedge bodies 41 and the elastic support member 70 and makes it possible for the separated wedge bodies 41 to be reliably separated in the diameter direction when being moved away from the wedge seating hole 31 of the wedge receiving body 30 during a process of assembling the tensioning steel wire 50, thus making the assembly of the tensioning steel wire 50 rapid and precise.

INDUSTRIAL APPLICABILITY

As described above, an internal fixer for an anchor having a releasable tensioning steel wire according to the present invention can be efficiently used in engineering work, in which holes are bored at a predetermined position in soft ground using a boring machine, a grout hose and a load-carrying body, which includes the tensioning steel wire and the internal fixer, are inserted into the boring hole, grout is injected through the grout hose, the injected grout cures with the load-carrying body, an external fixer is coupled to the other end of the tensioning steel wire, and the tensioning steel wire is pulled by a tensioning machine so that the grout and ground are tensioned, thus reinforcing the soft ground. That is, the present invention can be used in engineering work such as bracing work and engineering work for stabilizing a tunnel portal or for reinforcing a stone wall or a retaining wall.

Claims

1. An internal fixer for an anchor having a releasable tensioning steel wire, comprising:

a first outer body (10), with a tube coupling hole (11) and a body seating hole (13) coaxially formed in the first outer body (10) so that the tensioning steel wire (50) passes therethrough, and wedge receiving body support means provided on an inner surface of the body seating hole (13);

a wedge receiving body (30) seated by the wedge receiving body support means in the body seating hole (13) and having a conical wedge seating hole (31), into which separated wedge bodies (41) are seated;

a wedge unit (40) seated into the wedge seating hole (31) of the wedge receiving body (30) and comprising the three separated wedge bodies (41), which are arranged in a cone shape to hold the tensioning steel wire (50); and

a second outer body (20) supporting and covering both the wedge receiving body (30), which is seated in the body seating hole (13) of the first outer body (10), and the wedge unit (40), which is placed in the wedge seating hole (31) of the wedge receiving body (30).

2. An internal fixer for an anchor having a releasable tensioning steel wire, comprising:

a first outer body (10), with a tube coupling hole (11) and a body seating hole (13) coaxially formed in the first outer body (10) so that the tensioning steel wire (50) passes therethrough, and wedge receiving body support means provided on an inner surface of the body seating hole (13);

a wedge receiving body (30) seated by the wedge receiving body support means in the body seating hole (13) and having a conical wedge seating hole (31), in which separated wedge bodies (41) are seated;

a wedge unit (40) seated into the wedge seating hole (31) of the wedge receiving body (30) and comprising the three separated wedge bodies (41), which are arranged in a cone shape to hold the tensioning steel wire (50);

a second outer body (20) supporting and covering the wedge receiving body (30), which is seated in the body seating hole (13) of the first outer body (10); and

an elastic support member (70) provided in the second outer body (20) and elastically supporting, pushing and seating the wedge unit (40), which is placed in the wedge seating hole (31) of the wedge receiving body (30), into the wedge seating hole (31).

3. The internal fixer for the anchor having the releasable tensioning steel wire according to claim 1 or 2, wherein the wedge receiving body support means of the first outer body (10) along with the second outer body (20) supports the wedge receiving body (30) while no tensile force is applied to the tensioning steel wire (50), and the wedge receiving body support means allows the wedge receiving body (30) to be advanced along with the wedge unit (40) and to be fastened when tensile force is applied to the tensioning steel wire (50) after the internal fixer is installed in ground.

4. The internal fixer for the anchor having the releasable tensioning steel wire according to claim 3, wherein the wedge receiving body support means comprises a support protrusion (13a) provided on the inner surface of the body seating hole (13).

5. The internal fixer for the anchor having the releasable tensioning steel wire according to claim 3, wherein the wedge receiving body support means is realized by a tapered inner surface of the body seating hole (13) which decreases in diameter from a deep portion thereof to a shallow portion thereof.

6. The internal fixer for the anchor having the releasable tensioning steel wire according to claim 4 or 5, wherein the tapered inner surface of the body seating hole (13) and the support protrusion (13a), which is provided on the inner surface of the body seating hole (13), are formed in ring shapes around an entire circumference of the body seating hole (13).

7. The internal fixer for the anchor having the releasable tensioning steel wire according to claim 4 or 5, wherein the tapered inner surface of the body seating hole (13) and the support protrusion (13a) respectively comprise a plurality of tapered inner surfaces of the body seating hole (13) and a plurality of support protrusions (13a), which are provided on the inner surface of the body seating hole (13) and are spaced apart from each other.

8. The internal fixer for the anchor having the releasable tensioning steel wire according to claim 4, wherein the support protrusion (13a) of the body seating hole (13) is multi-stepped.

9. The internal fixer for the anchor having the releasable tensioning steel wire according to claim 3, wherein the wedge receiving body support means comprises a support O-ring (14) provided in a ring groove (13b) formed in the inner surface of the body seating hole (13), such that, when the wedge receiving body (30) is advanced by the tensioning steel wire (50), the support O-ring (14), which has supported an end of the wedge receiving body (30), comes into close contact with and holds an outer surface of the wedge receiving body (30).

10. The internal fixer for the anchor having the releasable tensioning steel wire according to claim 3, wherein the wedge receiving body support means comprises a C-shaped metal ring (15), which elastically expands in diameter and is provided in a ring groove (13b) formed in the inner surface of the body seating hole (13), such that, when the wedge receiving body (30) is advanced by the tensioning steel wire (50), the C-shaped metal ring (15), which has supported an end of the wedge receiving body (30), holds an outer surface of the wedge receiving body (30).

11. The internal fixer for the anchor having the releasable tensioning steel wire according to claim 10, wherein a ring stop groove (32) is formed in the outer surface of the wedge receiving body (30), such that, when the wedge receiving body (30) is advanced, the metal ring (15) is locked to the ring stop groove (32).

12. The internal fixer for the anchor having the releasable tensioning steel wire according to claim 10 or 11, wherein the wedge receiving body support means comprises: the C-shaped metal ring (15) provided in a ring seating groove (33) of the wedge receiving body (30); and a ring stop groove (13c) formed in the inner surface of the wedge seating groove (13).

13. The internal fixer for the anchor having the releasable tensioning steel wire according to claim 1 or 2, further comprising:

a wedge returning member (60) provided in the body seating hole (13) of the first outer body (10), so that, when the wedge receiving body (30) along with the wedge unit (40) is advanced and fastened to the body seating hole (13), the wedge unit (40), which is placed in the wedge seating hole (31) of the wedge receiving body (30), is biased backwards by the wedge returning member (60).

14. The internal fixer for the anchor having the releasable tensioning steel wire according to claim 13, wherein the wedge returning member (60) comprises a compression coil spring.

15. The internal fixer for the anchor having the releasable tensioning steel wire according to claim 13 or 14, further comprising:

a support ring member (61), having a flange on an end thereof, provided on an end of the wedge returning member (60) to support lower ends of the separated wedge bodies (41).

16. The internal fixer for the anchor having the releasable tensioning steel wire according to claim 13 or 14, wherein a spring seating hole (17) is formed in a bottom of the body seating hole (13) so that the wedge returning member (60) is installed in the spring seating hole (17), and a support protrusion (17a) is provided on a bottom of the spring seating hole (17) to hold an end of the wedge returning member (60).

17. The internal fixer for the anchor having the releasable tensioning steel wire according to claim 2, further comprising:

a cap member (45) fitted into an inner ring groove (43) formed in upper ends of the separated wedge bodies (41) constituting the wedge unit, so that an elastic support member (70) is fitted over the cap member (45) and the tensioning steel wire (50) is inserted more deeply.

18. The internal fixer for the anchor having the releasable tensioning steel wire according to claim 2 or 17, wherein the elastic support member (70) comprises a compression coil spring fitted over an outer surface of the cap member (45), which protrudes from the upper end of the wedge unit (40), without moving.

19. The internal fixer for the anchor having the releasable tensioning steel wire according to claim 2 or 17, further comprising:

a compression cover (71) provided between the separated wedge bodies (41) and the elastic support member (70) and seated on the separated wedge bodies (41) outside the cap member (45).