JPH0562181B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a coupling fitting for a steel wire such as a monostrand PC steel wire.

[Background of the invention] In recent years, the fixing method of pre-stressing method has been
Wedge type, screw type, and button type are known.

The method of connecting PC steel wires under tension is
The wedge type or screw type is used, but most of them connect multiple PC steel wires, and the one that can connect one wire to another and is practical and popular is the wedge type. .

However, in general, the wedge type has a larger amount of deviation during fixing (referred to as the set amount) than other fixing methods, and in order to reduce the set amount, it is necessary to push the wedge into the wedge cone (referred to as lock-off). For this reason, a lock-off mechanism is built into the jack, which is a factor in making the jack complicated and large.

In addition, in the wedge cone where the wedge is fixed,
A force is added to push it further. For this reason, the cone itself has a robust design, and is often made of larger hardware than screw or button types.

Furthermore, there are also known connecting fittings that are installed at intersections where the axes of steel wires, such as left and right monostrand PC steel wires, coincide, but since a stopper is provided separately for each PC steel wire, There is a problem that the members are large and the cost is high, and that the tensioning action is different for each member, so the use is limited.

Furthermore, Utility Application No. 56-31883 (Utility Application No. 57-
No. 145021) describes a technology using the aforementioned wedge type as a connecting fitting installed at the intersection of left and right PC steel wires, but in this technology, the wedge type is installed on the side of the steel wire that is not in contact with it. The wedge may loosen or come off when a sudden tensile force is applied or when vibrations are transmitted for a long time, resulting in the disadvantage that strong and stable tension cannot be obtained. Another disadvantage is that tension must be maintained after tension has completely finished, and it is impossible to maintain tension during intermittent tension or during tension. Furthermore, since the wedge and the wedge cone are separate members, they have the disadvantage that they tend to become separated on extremely complicated construction sites with poor footing, which may reduce work efficiency.

[Object of the Invention] Accordingly, an object of the present invention is to provide a connecting fitting for a steel wire such as a monostrand PC steel wire, which has high tension maintaining power and workability, is compact, and can be manufactured at low cost.

[Means for Solving the Problems] The inventors of the present invention have conducted intensive studies to solve the above objects, and as a result, have arrived at the present invention.

That is, the connecting fitting for a steel wire such as a mono-strand PC steel wire according to the present invention is provided at an intersection point where the axes of the left and right steel wires such as the mono-strand PC steel wire, each having one end fixed, are on the same axis. The left and right PC steel wires that are provided and enter the intersection are connected, and the other ends of the PC steel wires are pulled and tensioned from the intersection in an outward direction different from the axis, and the tension position is The connecting fitting has a holder into which the left and right PC steel wires can be inserted, and a stopper rotatably supported inside the holder, and the connecting fitting can firmly hold the left and right PC when under tension. When inserting the steel wire into the holder, the stopper rotates in the insertion direction of the left and right PC steel wires to allow insertion of the left and right PC steel wires, and when maintaining the left and right PC steel wires in the tensioned position. In this case, the stopper rotates slightly in the opposite direction to the insertion direction, and the upper and lower ends of the stopper simultaneously press the left and right PC steel wires against the inner wall of the holder, thereby removing the left and right PC steel wires from the holder. It is characterized by a structure that prevents it from coming off and maintains the tensioned position.

[Operation of the invention] According to the invention, the stopper inside the holder
Rotate slightly in the opposite direction to the direction in which the PC steel wire is inserted.
It has a configuration in which the tension force is maintained by simultaneously pressing each of the PC steel wires against the inner wall portion of the holder. That is, since the tension maintaining force for one PC steel wire acts synergistically as the tension maintaining force for the other PC steel wire, a strong tension force can be stably obtained.

[Example] Hereinafter, an example of the present invention will be described based on the accompanying drawings.

Fig. 1 is a schematic sectional view showing one embodiment of the connecting fitting of the present invention, Fig. 2 is a sectional view taken along the line of Fig. 1, and Fig.
The figure is a sectional view showing another embodiment, FIG. 4 is a plan view showing a reference example, and FIG. 5 is a longitudinal sectional view of the main part of the same figure. In the figure, reference numeral 1 denotes a connecting fitting, and the connecting fitting 1 is provided at an intersection where the axes _l1 of the left and right monostrand PC steel wires 2, 2, each having one end fixed, are on the same axis. 3 is a holder having passages 3A, 3A into which the left and right monostrand PC steel wires 2, 2 are inserted. The design of the vicinity of the exits of the passages 3A, 3A is preferably such that the PC steel wires ₂ , 2 lie on the axis l2.

Inside the holder 3, a stopper 4, which is a tension maintaining member that simultaneously contacts the left and right monostrand PC steel wires 2, 2 to maintain the tension, is attached to the shaft 4'.
is rotatably supported on the shaft.

The stopper 4 is designed so that the PC steel wire 2 is jammed (not shown).
See No. 61-162680. ), the stopper 4 rotates clockwise in the drawing direction in the direction of the arrow in FIG. 2,
Allow insertion of 2.

The upper and lower ends of the stopper 4 are slightly separated from the PC steel wire 2 by inserting and pulling the PC steel wires 2, 2, but when the tension ends or the jerking load decreases due to intermittent tension or interruption of tension, , PC
Steel wire 2 tries to return in the opposite direction of the arrow. At this time,
The stopper 4 rotates slightly counterclockwise, which is the opposite direction to the insertion direction, and the upper and lower ends of the stopper 4 simultaneously press the PC steel wires 2, 2 against the inner wall of the holder, thereby removing the PC steel wires 2, 2. to prevent it from coming off from the holder 3. By simultaneously pressing the PC steel wires 2 and 2, the tension maintaining force on one PC steel wire 2 acts synergistically as the tension maintaining force on the other PC steel wire 2, so that a strong and stable tension is maintained. can get. Therefore, even when a sudden tensile force is applied to one side of the PC steel wire 2, or when vibrations are transmitted for a long time, the tension remains stable.

In the connecting fitting 1 of the present invention, when the jacking load decreases, the simultaneous pressing of the stopper 4 on the PC steel wires 2, 2 acts immediately, so it can be used not only at the end of tensioning, but also during intermittent tensioning or tensioning. Tension can be maintained even during interruptions. .

Further, since the holder 3 and the stopper 4 do not become separated, there is no reduction in work efficiency due to the separation of parts at the site.

Although one embodiment of the connecting fitting 1 of the present invention has been described above, the present invention is not limited to the above, and can take various embodiments as described below.

It is preferable that the upper and lower ends of the stopper 4 are formed with blade-shaped portions 5, 5 that are parallel to each other in FIG.
Furthermore, the inner wall portion of the holder 3 facing the blade portions 5, 5 through the PC steel wires 2, 2 is also provided with the blade portions 5, 5.
It is preferable that blade-shaped portions 6, 6 are formed parallel to the above.

The cross-sectional shape of the blade portions 5 and 6 is preferably shaped close to the curvature of the cross-section of the PC steel wire, as shown in FIG. 2, in order to disperse grip surface pressure and prevent damage to the PC steel wire.

By being configured as above, the double-edged type 5,
When the PC steel wires 2, 2 sandwiched between 6 are returned due to a decrease in jacking load, they are pressed by the blade mold and are self-tightened.

The stopper 4 can be provided with a coil spring or the like (not shown) that acts counterclockwise, thereby making self-tightening more reliable.

That is, the PC steel wires 2, 2 from mutually opposite directions enter so as to spread the stopper 4 in the holder 3. A predetermined prestressing force is introduced to reduce the jacking load, and at the same time, this stopper 4 is dragged by the mutual PC steel wires 2, 2, and the tooth pattern bites into it and fixes it.

If necessary, the stopper 4 must be brought into play in order to release the tension. For this reason, it is preferable to provide a tension release mechanism 7. The tension release mechanism 7 is configured such that, for example, a piston 9 and a spring 10 are inserted into a threaded release hole 8, and the piston 9 is pushed with a screw 11 so that the stopper 4 can be rotated clockwise. Then, by applying and releasing (lowering) a tension load using a special jack (not shown), the tension force in the PC steel wires 2, 2 can be released.

Although one embodiment of the present invention has been described above, the present invention is not limited thereto. For example, both side surfaces 4'' of the stopper 4 may be expanded into an oval shape, and the oval-shaped both side surfaces 4'' may be attached to the holder 3.
The rotary shaft 4' can be held rotatably by the holder, thereby making the rotating shaft 4' unnecessary (see FIG. 3).

Of course, the PC steel wire 2 in the present invention includes not only a PC steel stranded wire (for example, a seven-strand PC steel wire) but also a single PC steel wire.

In addition, FIGS. 4 and 5 show reference examples in which a plurality of wedges are combined to serve as the stopper 4. Stopper 1 with inner wall as inclined surface 12
A holder 3 having 3A and 13B facing each other is formed. Then, tapered outer wedge pieces 14A, 14B for making the inclined surface 12 have an inclination angle of 7 degrees or less with respect to the axis _l1 of the PC steel wire 2, and inclined surfaces parallel to the wedge pieces 14A, 14B. tapered inner wedge pieces 15A and 15B having sloped surfaces that intersect with each other are prepared.

Therefore, one PC steel wire 2 is held between the inner and outer wedge pieces 15A and 14A, and the other inner and outer wedge pieces 15B and 14B are held between the holder 3 as shown in FIG. Set to .

The tensioning work in this reference example is the same as in the embodiment of the present invention, and as the jacking load decreases, each wedge piece 14A, 14B, 15A, 15B moves in the direction of the arrow shown in FIG. The tension will be maintained. Therefore, each wedge piece 14A,
It is preferable that the surfaces of 14B, 15A, and 15B in contact with the PC steel wire 2 match the curve of the PC steel wire 2 and have a blade shape.

As yet another reference example, it is conceivable to replace the stopper 4 with the wedge pieces 15A and 15B in the embodiment of the present invention shown in FIGS. 1 to 3 above. In the case of the reference example using these wedges, for example, it is possible to use a jig that presses the rear ends of the inner wedge pieces 15A and 15B in the direction of approaching each other, or conversely, to adjust the tension of the PC steel wire 2 as necessary. In order to release the inner wedge pieces 15A and 15B.
It is possible to use a jig that temporarily fixes the parts to the rear end of the parts and pulls them apart from each other.

Other reference examples include, for example, "Encyclopedia of Mechanisms" edited by Shigeru Ito, pp. 122-134, May 10, 1983.
You can refer to the description of ``Mechanism with anti-reverse action'' published by Rigakusha, 1st edition.

[Effect of the invention] According to the invention, the stopper inside the holder
Rotate slightly in the opposite direction to the direction in which the PC steel wire is inserted.
By having a structure that maintains the tension force by simultaneously pressing each of the PC steel wires against the inner wall portion of the holder, the tension maintenance force for one PC steel wire is equal to that of the other PC steel wire.
Since it acts synergistically as a tension maintaining force on the PC steel wire, strong and stable tension can be obtained.

Furthermore, even when a sudden tensile force is applied to one side of the PC steel wire, or when vibrations are transmitted for a long time, the tension remains stable.

Furthermore, when the jacking load decreases, the stopper simultaneously presses the left and right PC steel wires, so the tension is applied not only at the end of tensioning, but also during intermittent tensioning or interruption of tensioning. can be maintained.

Furthermore, since the holder and stopper that constitute the connecting fitting do not become separated, there is no reduction in work efficiency due to the separation of parts on site.

Furthermore, since the main components are the holder and the stopper, it can be manufactured compactly and at low cost.

[Brief explanation of the drawing]

Fig. 1 is a schematic sectional view showing one embodiment of the connecting fitting of the present invention, Fig. 2 is a sectional view taken along the line of Fig. 1, and Fig.
The figure is a sectional view showing another embodiment, FIG. 4 is a plan view showing a reference example, and FIG. 5 is a longitudinal sectional view of the main part of the same figure. 1... Connecting metal fittings, 2... PC steel wire, 3... Holder, 4... Stopper (tension maintaining member), 5...
...Blade mold part, 6...Blade mold part, 7...Tension release mechanism, 8...Release hole, 9...Piston, 10...
Spring, 11...screw.

Claims (1)

[Claims] 1 Left and right mono strands each fixed at one end
It is installed at the intersection where the axes of steel wires such as PC steel wires coincide, and the left and right sides that enter the intersection are
A connecting fitting that connects prestressed steel wires, pulls the other end of the prestressed steel wires, tensions the wires from the intersections in an outward direction different from the axis, and maintains the tensioned position. has a holder into which the left and right PC steel wires can be inserted, and a stopper rotatably supported inside the holder, and when the left and right PC steel wires are inserted into the holder under tension. The stopper rotates in the insertion direction of the left and right PC steel wires to allow the left and right PC steel wires to be inserted, and when the left and right PC steel wires are held in the tensioned position, the stopper rotates in the opposite direction to the insertion direction. The upper and lower ends of the stopper are rotated slightly to the left and right PCs.
For steel wires such as monostrand PC steel wires, characterized in that the steel wires are simultaneously pressed against the inner wall of the holder to prevent the left and right PC steel wires from coming off the holder and maintain the tensioned position. Connecting fittings.