JPH0745774B2 - PC cable insertion device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a device for inserting a PC steel wire into a sheath tube. In particular, the extension of the sheath tube is long, and the piping condition is not straight but sign. The present invention relates to a PC cable insertion device in the case of being arranged in a curved shape such as a curve.

<Prior art> When introducing prestress to a bridge or floor of a building, a PC cable must be inserted into a sheath pipe buried in concrete.

In that case, conventionally, a pushing device called a push-through machine or a method of pushing the PC cable from one end to reach the other end by human power has been adopted.

Such a method is possible if the distance between the structures is short,
This is a very difficult task when the distance is long and especially when a sheath tube has a curve such as a sine curve.

<Object of the present invention> The present invention has been made in such a case, insertion of a PC cable that can be easily inserted even if the insertion distance is long or the sheath tube forms a curve. The purpose is to provide a device.

<Structure of the Present Invention> Next, an embodiment of the present invention will be described.

<a> Treatment of the start end of the PC cable When the method of the present invention is adopted, it is necessary to attach a grip for retracting to the start end of the PC cable.

Therefore, the order of attaching the grips will be described first.

<B> Attaching Lubricant The cable 1 is composed of multiple PC steel wires.

Of this PC steel wire, the center several wires are separated (three wires in the embodiment shown in the figure), and this is particularly configured as the extended steel wire 2.

Then, the abrasive material 3 is attached at a fixed position from the end of the extended steel wire 2.

The friction material 3 is a material that increases friction, and for example, a coil spring is used.

As this coil spring, a coil spring having a shape with an acute angled section is used.

For example, it has a modified cross section such as a triangular cross section.

The coiled springs are used to bundle the extended steel wires 2 or to fit the extended steel wires 2 one by one.

In addition to the coil spring, for example, a structure in which sand, alumina powder, carbon powder, etc. are attached to the periphery of the extended steel wire 2 can be used as the friction material.

In short, it suffices to apply a frictional force around the extended steel wire 2.

<C> Cutting of Steel Wire The end side from the position where the abrasive 3 is attached is cut while leaving only the extended steel wire 2.

Alternatively, before attaching the abrasive material 3, the extended steel wire 2 is left alone and cut.

Then, only the extended steel wire 2 is exposed to the end of the cable 1 by a certain size.

<D> Fitting of compression pipe and compression The compression pipe 4 is fitted to the outer periphery of the position where the abrasive material 3 is attached. (FIG. 2) The compression tube 4 is a tubular body with both ends open, having an inner diameter slightly larger than the outer diameter of the cable 1.

After fitting, the compression tube 4 is crushed by applying a high pressure from its surroundings. (Fig. 3) Since the friction material 3 is located inside the extended steel wire group 2,
When the compression tube 4 is deformed, the friction material 3 bites into the surface of the extended steel wire 2 and is bonded with a strong force.

As a result, the end of the cable 1 is bundled by the compression pipe 4, and only some of the extended steel wires 2 are exposed from the end of the compression pipe 4 through the compression pipe 4.

<E> Attachment of end grip An end grip 5 is attached to the end of the extended steel wire 2. (FIG. 4) The end grip 5 is composed of a grip cylinder 51 having both ends open, a plurality of wedges 52 and a spring 53, which are divided in a direction parallel to the extended steel wire 2.

At the time of mounting, the extended steel wire group 2 is housed in the grip cylinder body 51 from one side, the wedge 52 is fitted from the opposite side, and the wedge 52 is pressed inward by the spring 53.

Then, the hook cylinder 54 is attached to the grip cylinder 51 by a method such as screwing, and the wire W is attached to the hook cylinder 54.

The end grip 5 does not restrain all PC steel wires,
Constrain only some steel wires.

Therefore, the outer diameter of the end grip 5 does not become extremely larger than the outer diameter of the cable 1, and the insertion into the sheath tube is smooth.

<How to use> Next, a method for inserting the PC cable 1 using the above device will be described with reference to FIG.

<a> Embedding the sheath pipe Before the concrete is poured, the sheath pipe is embedded inside the concrete structure.

<B> Insertion of lead-in wire Insert the lead-in W into the sheath tube. The outer diameter of the wire W is smaller than the inner diameter of the sheath tube.

After the concrete is hardened, one end of the pull-in wire W is attached to the hook cylinder 54.

If the wire W is not directly attached, but is attached via a carabiner or a swivel, for example, it is easier to pull in the wire.

<C> Pulling the cable The wire W is wound up, but at this time, the end opposite to the side where the hook tube 54 is attached is wound up with a winch.

Then, the cable 1 attached to the other end of the wire W is drawn into the sheath tube.

The insertion is complete when the cable 1 penetrates the sheath tube and is exposed from the opposite end.

After that, the cable 1 is tensioned by applying a pulling force by a known method.

<Effects of the Present Invention> With the recent increase in the size of the structure, the extension of insertion of the PC cable is increasing, and the conventional method requires extremely complicated work, time, and skill.

Moreover, when pushing the cable from one end of the sheath tube using push-through, the limit is 100 m at most.
It is a degree.

As described above, the insertion method of the present invention is to insert the PC cable into the sheath tube by pulling it instead of pushing it in. Therefore, there is almost no limitation on the length, and the PC tube can be smoothly installed. .

Further, the end grip used in the present invention has a structure in which not all PC steel wires are constrained, but only some steel wires are constrained.

Therefore, the outer diameter of the end grip does not become extremely larger than the outer diameter of the cable, and the insertion into the sheath tube becomes easier.

Further, in the prior art, as a restraint means for the entire steel wire, there is a means for welding or band binding only the steel wire group around the extended steel wire (Japanese Utility Model Publication No. 60-77653).

However, as in the present invention, since the extended steel wire and the steel wire around the extended steel wire are not joined, if only the extended steel wire is pulled at the time of construction, the surrounding steel wire swells down in the axial direction and swells, Reliable construction cannot be realized.

On the other hand, in the present invention, the means for restraining the entire steel wire restrains the entire steel wire by the compression pipe in the state where the friction material is interposed between the extended steel wire and the other steel wires located around the extended steel wire. Is configured to.

Therefore, due to the pressure shrinkage of the compression tube, the abrasive material bites into the surfaces of the extended steel wire and the other steel wire around it, and a strong bonding force can be obtained.

Therefore, even if only the extended steel wire is pulled during construction, the surrounding steel wire does not slide axially downward and swell, and reliable construction can be realized.

[Brief description of drawings]

 1 to 5: Illustration of manufacturing process of pulling device FIG. 6: Illustration of construction state

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Iku Ishikawa Iku Ishikawa 1-25-1 Nishi Shinjuku, Shinjuku-ku, Tokyo Within Taisei Construction Co., Ltd. Within Kogyo Co., Ltd. (56) Reference JP-A-1-154965 (JP, A) JP-A-56-73770 (JP, A) Actual development Shou-60-77653 (JP, U)

Claims (1)

[Claims] 1. An extended steel wire that is extended to the center of a plurality of restrained steel wires, a grip that holds the end of the extended steel wire, and a pulling wire attached to the grip. In the insertion device of the PC cable, a friction material is interposed between the extended steel wire and other steel wires located around the extension steel wire, and the tubular body is provided around the entire outer circumference of the steel wire at the position where the friction material is interposed. A PC cable insertion device, characterized in that the entire steel wire is constrained by pressing and mounting.