JPH045650Y2 - - Google Patents

Description

[Detailed explanation of the invention] [Field of industrial application] This invention is applicable to post-tension systems.
This relates to a tensioning device for tensile materials such as PC strands.

[Prior art and its problems] In the post-tension system, when tension
An important issue is to reduce the length of the tensile material such as PC strand that protrudes from the anchor head (strand gripping margin) as short as possible.

That is, in the case of tensile materials that require re-tensioning after several years, it is necessary to secure a gripping allowance for the strands for gripping, and during this time it is necessary to protect the ends of the strands by preventing rust. If the strands have to be held longer, protecting the ends of the strands is difficult and uneconomical.

For this purpose, a tensioning device as shown in FIG. 5 is used. An inner cylinder b is fitted into an outer cylinder a so as to be slidable by hydraulic pressure, and a gripping mechanism (pulling head) c for the strand s is built into the tip of the inner cylinder b. With such a tensioning device, the gripping mechanism c can be brought closer to the anchor head d, and the gripping margin for the strand s can be shortened.

However, even with such a device, it is necessary to ensure a certain length in order to check from the outside whether or not the strand s is accurately gripped by the gripping mechanism c. and the anchor head d, and the anchor head d is moved close to and separated from the anchor head d by hydraulic pressure.
Since there is a built-in pressing plate e that plays the role of pushing the inner wedge, the holding length of the strand s is 30 cm.
degree is necessary.

In addition, since the entire mechanism is integrated, it is heavy and requires a crane or other means to transport it, and when it is re-tensioned, it will be necessary to erect extensive scaffolding at the site again.
Therefore, such an integrated tensioning device requires an extremely large amount of labor for transportation and temporary installation.

This idea was made to improve the above-mentioned shortcomings; it is possible to minimize the length of the strands, etc., and it is easy to transport, and there is no need to set up extensive scaffolding on site. The purpose is to provide tensioning devices for PC strands, etc.

[Means to solve the problem]

The tensioning device for tensioning material according to this invention solves the above problems by comprising a separate ram chair, a pulling head, a coupling device, a reaction force receiving frame, and a jack.

〔Example〕

This invention will be explained in detail below based on the illustrated embodiments.

(1) Ramtier Air The ramtier air 1 is a member placed in contact with the anchor head 2. In the embodiment, the anchor head 2 is disc-shaped, and an annular locking portion is provided protrudingly on the opposite surface of the anchor head 2, and an annular surface and a circular concave surface are formed in two stages inside the locking portion 11. The outer annular surface has a stepped inner diameter that is approximately equal to the outer diameter of the anchor head 2 and serves as a contact surface for the anchor head 2, and the inner circular concave inner surface has a stepped inner diameter that is slightly larger than the outer diameter of the anchor head 2. A hole 12 formed small and corresponding to the tension member insertion hole 21 of the anchor head 2
is drilled.

With the side surface constructed as described above facing the anchor head 2, the stepped portion of the locking portion 11 surrounds the anchor head, and the anchor head 2 is brought into contact with the inner annular surface and inserted into the stepped portion. A clearance W is secured between the surface of the anchor head 2 and the inner circular concave surface to allow movement of the head of the wedge 22 inserted into the insertion hole of the anchor head 2.

(2) Pulling head The pulling head 3 is a member for gripping a tensile material such as a strand, and has a tensile material insertion hole 31 corresponding to the insertion hole 21 of the anchor head 2 as shown in FIGS. 3 and 4. , the wedge 4 is inserted into the insertion hole 31.

An insertion hole 31 is provided on the inner periphery of one end of the insertion hole 31 in a tapered shape so that the inner diameter gradually increases as it approaches the outer surface.
A wedge 4 having a truncated conical shape and having an insertion hole 41 formed therein in the axial direction and divided into a plurality of parts is inserted in sliding contact with the tapered surface. Further, a male thread 32 is provided on the outer periphery.

This pulling head 3 is located on the opposite side of the ram chair 1 from the anchor head 2. The end of the tensile material s, such as a strand, protruding from the anchor head 2 is inserted into the insertion hole 31 of the pulling head 3 and the insertion hole 41 of the wedge 4, and the wedge 4 is pressed into the tapered surface of the insertion hole 31. Grasp the wedge 4.

At this point, it can be confirmed whether the tension member s is securely gripped by the pulling head 3. That is, even if the length of the tension member s is short, it is easy to check whether it is held between the wedges 4 or not because it can be visually checked.

(3) Connector The connector 5 is a member that connects the pulling head 3 to a jack 7, which will be described later.

The connector 5 is formed into a cylindrical shape. Connector 5
The inner diameter of one end of the pull head 3 is the same as the outer diameter of the pulling head 3, and a female thread 51 is threaded on the inner peripheral surface of the end. A small-diameter connecting hole 52 is bored at the other end, and a female thread 53 is screwed into the inner peripheral surface of the connecting hole 52.

The connector 5 is attached to the pulling head 3 by screwing the female thread 51 of the connector 5 onto the male thread 32 on the outer periphery of the pulling head 3.

(4) Pressure receiving stand The reaction force receiving stand 6 is a member interposed between a structure such as a bridge on which a tension member is installed and a jack 7 described later, and is a member that receives a reaction force when a strand or the like is tensed.

In the embodiment, the reaction force receiving frame 6 is formed into a hollow cylindrical shape, and a hole 61 is formed in the side surface. An annular pedestal 62 is provided protruding from one end of the reaction force receiving frame 6. An annular locking portion 63 is attached to the cylindrical inner surface of the pedestal 6, and the length r between the locking portion 63 and the end of the pedestal 6 is the length from the surface of the bearing plate 23 to the surface of the pulling head 3 of the ram chair 1, which will be described later. It is approximately the same as the length of p. The total length of the reaction force receiving frame 6 must be equal to the stroke of the jack 7, which will be described later.

The end of the reaction force receiving frame 6 on the side where the locking portion 63 is formed is brought into contact with the bearing plate 23 which is a structural body. The movement of the ram chair 1 is restricted by an annular locking portion 63 mounted inside the cylinder of the reaction force receiving pedestal 6, and the ram chair 1 is held in contact with the anchor head 2.

(5) Jacket The jack 7 is used to tension the tensile material s such as a strand, and its driving part is brought into contact with the reaction force receiving pedestal 6, and its reciprocating part is connected to the connector 5.

In the embodiment, the jack 7 is composed of a center hole jack 71 which is a driving part and a tension bar 72 which is a reciprocating part. Male screws 73 and 74 are screwed on both ends of the tension bar 72, and the male screw 73 at one end is screwed into the female screw 53 of the connecting hole 52 of the connector 5 to connect, and the other end is connected to the center hole jack 71. Insert it inside Natsu 7
5 onto the male thread 74. The center hole jack 71 is brought into contact with the pedestal 62 of the reaction force receiving frame 6.

Further, as the jack 7, a known hydraulic cylinder constituted by an ordinary cylinder and a rod, or other known screw jacks can be used.

(6) Tensioning work As described above, the tensioning device consisting of each separate member will be assembled in order on site and the tensioning work will begin.

The jack 7 is driven to pull the pulling head 3 toward the jack 7, thereby tensioning the tension member s. At this time, the wedge 22 inside the anchor head 2 is drawn toward the jack 7 side together with the tension member s and comes out of the insertion hole, and the wedge 22 is pulled out from the insertion hole at the clearance w.
2 spreads to release the tension member s from being held. The wedge 22 comes into contact with the ram chair 1 and is prevented from moving further toward the jack 7 together with the tension member s. Required length nervous and jealous 7
By returning the reciprocating part slightly, the wedge 22 becomes the tensile member s.
At the same time, the anchor head 2 is inserted into the insertion hole again, and the tension material s is clamped to complete the fixing.

The tensioning device can be disassembled by reversing the installation order.

[Effect of idea]

The tensioning device for PC strands and the like according to this invention has the above-mentioned configuration, and can obtain the following effects.

(a) Since each separate member is assembled in sequence on site, once the tension material is clamped by the wedge of the pulling head, the clamping of the tension material can be visually confirmed up close, making it easy to re-tension. The gripping allowance for this is approximately the thickness of the ram chair and the pulling head.

Compared to conventional tensioning devices, only a very short gripping distance is required, and in experiments, tensioning is possible as long as the strand protrudes from the anchor head by about 10 cm. Therefore, it is possible to tension the tensioning material, which was previously thought to be impossible to retension. Re-tensioning work is possible even if the anchor is cut near the anchor head.

(b) Furthermore, since each member of the tensioning device is separate, each member can be transported individually, and there is no need to use a large crane. Furthermore, there is no need to construct large-scale scaffolding for this purpose, and the labor required for transportation and temporary construction can be greatly reduced.

(c) Since the pulling head has a cylindrical connecting tool screwed onto the male thread on the outer periphery, and the connecting tool is connected to the reciprocating part of the jack, it is possible to make tension material insertion holes pass through the entire surface of the pulling head. The pulling head can be shaped to match the shape of the anchor head.

In addition, in order to match the shape of the anchor head, such as the number and position of tension members, by selecting only the pulling head, the other members can be used in common.
It is simple and can be manufactured at low cost.

(d) In order to prevent the wedge of the anchor head from slipping out of the hole, only a ram tie air is used to ensure clearance, so the structure is extremely simple and can be manufactured at low cost.

[Brief explanation of the drawing]

Fig. 1 is a side view of an embodiment of this invention, Fig. 2 is an exploded perspective view, Fig. 3 is a vertical sectional view of the pulling head, Fig. 4 is a front view of the pulling head, and Fig. 5 is a conventional tensioning device. FIG. 3 is a longitudinal cross-sectional view of the device. 1... Lamb chair air, 2... Anchor head,
3... Pulling head, 4... Wedge, 5... Connector, 6... Reaction force receiving frame, 7... Jacket, 8
...Tensile material.

Claims (1)

[Claims for Utility Model Registration] An annular locking portion is protruded to form a contact surface for the anchor head on the inside, and a circular concave surface is formed with a clearance inside the contact surface, and within this circular concave surface. a ram tie air having a tension material insertion hole passed through it; a pulling head disposed opposite to the ram tie air, having a male screw threaded on its outer periphery and having a tension material insertion hole having a wedge insertion hole passed therethrough; A connecting tool has a female thread for connecting the jack on the inner periphery of the other end, and a female thread for connecting the plink head on the inner periphery of the other end. A hollow cylindrical reaction force receiving pedestal with an annular locking part installed inside to restrict movement, a drive part that comes into contact with the reaction force receiving pedestal, and a male thread connected to the connector inside the reaction force receiving pedestal with a screw threaded at the tip. 1. A tensioning device for tensioning material, comprising a jack having a reciprocating part.