JP2001303716A - Compression grip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anchoring piece having the high anchoring efficiency and excellent workability at site while having a compact structure. SOLUTION: This compression grip 1 comprises a straight cylindrical sleeve 2 provided with a groove 6 crossing the axis thereof on an outer surface, and an inner surface formed into a truncated conical surface 5 inclined at a predetermined angle in a range of 1 deg.-7 deg. with respect to the axis and freely fitted to a PC wire 4, and an interposing member 3. The interposing member 3 is formed in a totally split truncated conical cylinder equally split into at least two portions in the longitudinal direction, or a partially split truncated conical cylinder equally split into at least two portions in the circumferential direction with a slit 9 extending in the axial direction, and interposed in the sleeve 2 around the PC wire 4, with an outer surface thereof formed in the truncated conical surface 7 corresponding to the truncated conical surface 5 of the predetermined angle of the sleeve 2 and a tooth profile 8 formed on an inner surface thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compression grip, and more particularly, to an end of a steel wire or a steel stranded wire for prestressed concrete (hereinafter referred to as PC steel wire) in a prestressed concrete method in the field of civil engineering and construction. The present invention relates to a compression grip as a fixing tool for fixing the compression grip to a compression grip.

[0002]

2. Description of the Related Art Prior art relating to this kind of compression grip (hereinafter referred to as a fixing device) is disclosed in Japanese Patent Publication No. 51-3 / 1973.
As described in Japanese Patent Publication No. 0373, etc., the fixing device is a cylindrical thick steel sleeve, a spring wire steel (triangular wire) having a triangular cross section, or a coil formed by machining both outer surfaces to increase frictional force. , Cylindrical or semi-cylindrical thin-walled steel material (nail) is inserted, and the PC steel wire, the sleeve and the insert are mechanically crimped by swaging or the like. .

The important performance required of the fixing device is the fixing efficiency between the PC steel wire and the fixing device comprising a sleeve and an interposer.
Since the steel wire and the fixing device are fixed, the frictional area between the PC steel wire and the fixing device must be increased to obtain the required fixing efficiency. As a result, the fixing tool is increased in size because the efficiency of the crimped sleeve is prevented from lowering due to the expansion direction of the sleeve.

[0004]

SUMMARY OF THE INVENTION
It is inevitable that conventional fixing devices increase in both length and diameter, and therefore, making the fixing device compact in terms of space, weight reduction, cost, and the like has become an important issue for stakeholders. It was.

[0005] The present invention has been made in order to solve such a problem, and therefore, an object of the present invention is to provide:
In order to meet the needs of the art, it is an object of the present invention to provide an improved fixing device having a high fixing efficiency and excellent workability in the field, while having a compact structure.

[0006]

The present invention has the following configuration to achieve the above object. That is, the invention of claim 1 according to the present invention is characterized in that a straight cylindrical sleeve that is loosely fitted to a steel wire or a stranded steel PC wire,
A sleeve interposed in the sleeve around the C wire, the sleeve having a groove intersecting the axis line provided on an outer surface, and an inner surface having a predetermined angle within a range of 1 ° to 7 ° with respect to a central axis. The insert is formed in a frusto-conical surface inclined at an angle, and the insertion material is provided with a fully cracked frusto-conical cylinder vertically divided into at least two equal parts or a slit extending in an axial direction at least equally divided into two. Wherein the outer surface is formed as a frusto-conical surface corresponding to the frusto-conical surface at the predetermined angle of the sleeve, and a tooth profile is formed on the inner surface. It is a compression grip.

According to a second aspect of the present invention, there is provided a compression grip according to the first aspect.
The groove on the outer surface of the sleeve is so shallow that the lubricant can be absorbed therein, and is constituted by a multiplicity of line grooves extending in parallel with the sleeve axis.

According to a third aspect of the present invention, there is provided the compression grip according to the first or second aspect, wherein the tooth profile on the inner surface of the interposer has a triangular cross-sectional shape arranged at a fine pitch. Characterized in that the spiral groove is formed.

According to the present invention, the inner surface of the sleeve is inclined at a predetermined angle in the range of 1 ° to 7 °, and the insert has an inclined outer surface corresponding to the inner surface of the sleeve and the inner surface. And the two members are fixed to the PC steel wire by crimping, so in addition to the frictional force of the sleeve and the interposer being pressed against the PC steel wire, the PC steel wire is pulled in by tension. Since the wedge action acts between the inclined surface of the inner surface of the sleeve and the outer surface of the insertion material when
As the interposer is pulled in with the PC steel wire, side pressure is applied to the PC steel wire.

Originally, in a state where the fixing device according to the present invention is used, it is possible to sufficiently cope with the fixing by only the frictional force due to the pressure bonding. However, even if the tension is excessively applied eventually, the wedge may be used. The effect has sufficient fixing ability, and the friction area for obtaining the required fixing efficiency can be reduced, and the length and diameter of the fixing device are reduced to make the fixing device more compact than the conventional one. Can be provided.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be specifically described below with reference to the accompanying drawings.

FIG. 1 is a front view showing a cross section of an upper half portion of a fixing tool according to an embodiment of the present invention fixed to a PC steel wire. FIG. 2 is a front view of the sleeve of the fixing device shown in FIG. FIG. 3A is a front view showing an upper half section of the interposer of the fixing tool shown in FIG. 1 and FIG.
In the same manner, the insertion material is shown in a right side view.

[0013] The PC steel wire buried in the concrete in advance is used for the purpose of applying a compressive force to concrete having a weakness to tensile force to reinforce the concrete, and therefore, to prevent the tension from being released, the PC steel wire is used at both ends of the concrete. It is well known that a fixing device is installed at the end of a line.

Referring to FIGS. 1 to 3, a fixing device 1 according to the present invention is composed of a sleeve 2 and an insert 3.
The sleeve 2 is a member for loosely fitting to the end portion of the PC steel wire 4, and is, for example, a short straight cylindrical body made of steel. The sleeve 2 has an outer surface provided with a plurality of grooves 6 intersecting the axis, and a frusto-conical cone whose inner surface is inclined at a predetermined angle θ within a range of 1 ° to 7 ° with respect to a central axis. Formed on surface 5.

On the other hand, the insertion member 3 is a member for inserting as a wedge member into the sleeve 2 around the PC steel wire 4 in a state where the sleeve 2 is loosely fitted to the end portion of the PC steel wire 4. A partially cracked frustoconical cylinder having a higher hardness than the sleeve 2 and made of, for example, Cr-Mo steel is used. The insertion member 3 has an outer surface formed on a frusto-conical surface 7 having a fitting relationship shape corresponding to the frusto-conical surface 5 of the sleeve 2, and a tooth shape 8 is formed on the entire inner surface. The interposer 3 of the present embodiment is formed in a partially split truncated conical cylindrical body.
A slit 9 extending from the large diameter side and leaving a part of the end on the opposite side in the axial direction from the large diameter side is cut out at the equally divided position.

Incidentally, the insert 3 of the fixing device 1 according to the present invention is
Either a partially cracked frustoconical cylinder or a fully cracked frustoconical cylinder is selectively used. In the case of a partially cracked frustoconical cylinder, at least two equally divided axial directions are used. It is an integral cylindrical body having an extended slit 9 cut out,
In the case of a fully cracked truncated conical cylinder, it is necessary that the cylinder be a split-type cylinder vertically divided into at least two equal parts.

The grooves 6 of the sleeve 2 are so shallow as to allow the lubricating oil coated on the surface to be adapted during the surface reduction by the swage method, and are parallel to the sleeve axis. Are preferably formed by spiral grooves, for example, and are formed by spiral grooves having a triangular cross-sectional shape arranged at a fine pitch. Etc. are preferred.

The fixing device 1 according to the present invention as shown in FIG.
Referring to FIG. 3 to FIG. 3, the end of PC steel wire 4 is connected to the terminal side (FIG. 1).
(Right side), the sleeve 2 is loosely inserted with the small-diameter cylindrical hole side first, and then the insertion member 3 is inserted into the sleeve 2, or the sleeve 2 and the insertion member 3 are combined first. The fixing device 1 is loosely inserted into the end of the PC steel wire 4, and then the insertion material 3 is pressed strongly by a jig to fix the fixing device 1.
At a predetermined position of the PC steel wire 4. Subsequently, the fixing tool 1 is subjected to a surface reduction process by a swaging method to fix the fixing tool 1 to a PC.
The fixing (grip) is performed on the end of the steel wire 4, and the fixing operation of the fixing tool 1 is completed.

Thus, by pressing the fixing device 1 to the end of the PC steel wire 4, in addition to the frictional force caused by the press-fitting of the PC steel wire 4 and the sleeve 2 to the interposer 3, the inner surface of the sleeve 2 is pressed. Side pressure generated by the wedge effect due to the inclination of the outer surface of the insert 3 also acts, so that a strong fixing ability can be exhibited.

The reason why the inclination angle θ of the frustoconical surfaces 5 and 7 between the sleeve 2 and the interposer 3 is specified in the range of 1 ° to 7 ° is that the outer diameter of the fixing device 1 is kept as small as possible. However, in order to sufficiently exhibit the wedge effect, the angle is at most 7 ° at the maximum. In order to minimize the axial length of the fixing device 1 and minimize the wedge effect, at least 1 ° is required.
° is the limit.

The provision of the tooth profile 8 on the inner surface of the insert 3 allows the frictional force between the insert 3 and the PC steel wire 4 to be strong, while the groove on the outer surface of the sleeve 2. By providing the lubricating oil 6, the lubricating oil is well adapted to the entire outer surface of the sleeve 2, and it is possible to smoothly and efficiently perform the swaging method.

[0022]

Embodiments of the present invention will be described below with reference to the following tables. For a 28.6 mm PC stranded wire, the fixing device according to the present embodiment (however, the inclination angle of the truncated conical surfaces 5 and 7 = 2.5 °) and the conventional fixing device of Comparative Example 1 (however,
Fixing three types, a crimping type and a comparative example 2 (however, a wedge type), and actually measuring the grip characteristics of each, the results shown in Table 1 were obtained.

[0023]

[Table 1] Note: Fixing efficiency is indicated by the ratio of the standard tensile load to the breaking tensile load.

As is apparent from the above results, when the standard tensile load and the fixing efficiency are the same, in this embodiment, a fixing device having a compact structure in which both the sleeve length and the outer diameter are small is obtained. Therefore, it is clear that according to the present invention, it is possible to provide a fixing device having a sufficient fixing ability and a reduced size.

[0025]

The present invention is embodied in the form described above and has the following effects.

According to the present invention, the inner surface of the sleeve is inclined at an angle of 1 ° to 7 °, and the outer surface of the insert is similarly set at 1 ° to 7 °.
Angled at an angle of ° and a tooth profile was formed on the inner surface of the insert, so that it was fixed to the PC steel wire by crimping, in addition to the frictional force caused by the crimping of the PC steel wire and the sleeve with the insert, When the PC steel wire is pulled in by tension,
Since the inner surface of the sleeve and the outer surface of the insertion material are inclined with respect to the drawing direction, side pressure is applied to the PC steel wire as the insertion material is drawn in together with the PC steel wire. Therefore, in the fixing device according to the present invention, although the original fixing ability is sufficiently exhibited only by the frictional force due to the pressure bonding, even when ultimately excessive tension is applied, the effect of applying the side pressure is more sufficient. As a result of exhibiting the fixing ability, a friction area for obtaining a necessary fixing efficiency can be reduced, and a fixing device which is more compact than a conventional fixing device can be provided.

Further, by adjusting the bite of the interposer, it is possible to cope with a problem that the holding of the tension applied to the PC steel wire is reduced. Therefore, without changing the size of the fixing tool,
It can be easily coped with only by changing the inclination angle of the sleeve and the interposed member.

[Brief description of the drawings]

FIG. 1 is a front view showing an upper half section in a state where a fixing tool according to an embodiment of the present invention is fixed to a PC steel wire.

FIG. 2 is a front view of a sleeve in the fixing device shown in FIG. 1;

FIG. 3A is a front view showing a cross section of an upper half of an interposer in the fixing device shown in FIG. 1, and FIG. 3B is a right side view of the interposer.

[Explanation of symbols]

1. Fixing device 2. Sleeve 3.
... Insert material 4 ... PC steel wire 5 ... Frustoconical surface (inner surface) 6
... groove (line groove) 7 ... frusto-conical surface (outer surface) 8 ... tooth shape (spiral groove) 9
…slit

 ────────────────────────────────────────────────── ─── Continued on front page (72) Inventor Mikio Hamana 10-1 Nakahamacho, Amagasaki City Shinko Steel Wire Industry Co., Ltd. F-term (reference) 2E164 AA02 AA31 DA23

Claims (3)

[Claims] 1. A straight-cylindrical sleeve loosely fitted to a steel wire or a stranded steel PC wire, and an insertion material inserted into the sleeve around the PC wire. Are formed on the outer surface, and the inner surface is formed as a frusto-conical surface inclined at a predetermined angle in the range of 1 ° to 7 ° with respect to the central axis, and the interposer is divided into at least two equal parts. A vertically split full-truncated frusto-conical cylinder, or a partially split truncated frusto-conical cylinder having at least two equally-divided axially extending slits, the outer surface of which is truncated at the predetermined angle of the sleeve. A compression grip formed on a frustoconical surface corresponding to the conical surface and having a tooth profile formed on an inner surface. 2. The compression grip according to claim 1, wherein the groove on the outer surface of the sleeve is formed so as to be shallow enough to allow the lubricant to be absorbed therein, and comprises a plurality of line grooves extending in parallel with the axis of the sleeve. 3. The compression grip according to claim 1, wherein the tooth profile on the inner surface of the interposer is formed of a spiral groove having a triangular cross section arranged at a fine pitch.