JPH07197599A - Electric charge eliminating device for pc steel material - Google Patents

Abstract

PURPOSE:To remove a tensional load of PC steel material with a simple structure. CONSTITUTION:In an electric charge removing device for PC steel where the PC steel material 3 is sandwiched by plural wedges 2 and this is inserted in and fixed to a wedge receiver 1 having a tapered hole 5, a holding ring 4 is oppositely arranged in front of the wedge receiver 1, and the wedges 2 are fixed to the inner periphery of this holding ring 4. When electric charge is removed, the wedges 2 are pulled out of the taper hole 5 by re-tension of the PC steel 3, and support bars 13 are interposed between the wedge receiver 1 and the holding ring 4 integrally formed with the wedges, and are held so that the wedges 2 are not returned to the taper hole 5, and when tension is removed, elongation of the PC steel is restored, and tensile force is removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for unloading a strained PC steel load in a PC structure.

[0002]

2. Description of the Related Art When constructing a PC structure, a load that works effectively during construction may have an adverse effect after completion and the PC steel material may become unnecessary. In this case, it is necessary to loosen the load of the PC steel material, but conventionally this type of unloading has been performed by the device as shown in FIGS. 6 and 7.

First, as shown in FIG. 6, a plurality of shims 23 each having a U-shaped hole with one end opened are stacked between the fixing tool (the wedge 20 and the wedge receiver 21) and the bearing plate 22, and a PC steel material 24 is formed. It is installed in a thickness corresponding to the amount of elongation (see Fig. A). At the time of unloading, re-tensioning is performed using the ram chair 25 as shown in FIG. (B), a gap is opened between the fixing tool and the shim 23, and the shim 23 is pulled out to loosen the load.

Next, in the one shown in FIG. 7, the outer circumference of the wedge receiver 21 is threaded, and this is screwed into a ring 26 having an inner peripheral surface corresponding to the screw surface (see FIG. A). Ring 26
Corresponds to the total amount of elongation of the PC steel material 24 and the screwed length of the wedge receiver 21. At the time of unloading, re-tension using a ramchair (not shown), and ring 26 as shown in (B).
Turn to loosen the load.

[0005]

However, in the above case, a shim corresponding to the elongation amount of PC steel is required, and P
As the elongation of C steel material increases, the thickness of the shim also increases, which makes mounting and dismounting complicated and the workability is poor. In addition, in the case of (3), it is necessary to thread the outer circumference of the wedge receiver, and since the ring having the inner circumference is also used, it becomes expensive. In particular, when the elongation amount of the PC steel material is large, the ring also becomes long and more expensive.

[0006]

The present invention has been made to solve the above problems, and is characterized in that a PC steel material is sandwiched by a plurality of wedges and is inserted into a wedge receiver having a tapered hole. In the device for unloading PC steel material, the retaining ring is arranged in front of the wedge receiver, the wedge is fixed at the inner circumference of the retaining ring, and when re-tensioning occurs due to unloading,
It was equipped with a support rod interposed between the retaining ring and the wedge receiver. When unloading, the wedge is pulled out from the taper hole by re-tensioning the PC steel material, and the support member is interposed between the retaining ring and the wedge receiver that are integral with the wedge to hold the wedge so that it does not return to the taper hole. When is released, the elongation of the PC steel returns and the tension is released.

In this way, when the tension is re-tensioned, the wedge is supported by interposing the support rod. In this case, it is preferable to chamfer the peripheral edges of the retaining ring and the wedge receiver so that the support rod can be easily attached. Further, a cutout portion serving as a bearing surface of the support rod may be provided in the holding ring and the wedge receiver so that the support rod is securely mounted. To further improve workability, it is preferable to use a support rod whose length can be adjusted.

[0008]

EXAMPLES Examples of the present invention will be described below. FIG. 1 shows an outline of the device of the present invention before unloading, (A) is a front view and (B) is a side view. In the figure, 1 is a wedge receiver, 2 is a wedge, which constitute a fixing device for the PC steel material 3. In the device of the present invention, this wedge is fixed to the retaining ring 4. First, the wedge receiver 1 has a cylindrical shape with a tapered hole 5 as shown in FIG. 3 (A), and one end (the wide side of the tapered hole) of the wedge receiver 1 is chamfered on the entire circumference. Further, a tongue-shaped notch 6 serving as a seating surface of a support rod, which will be described later, is formed at an opposite position of the chamfered peripheral edge. A plan view and a sectional view of the cutout portion 6 are shown in FIGS.

Next, when the retaining ring 4 is retensioned due to unloading,
The wedge 2 is an annular one that holds the wedge 2 so that it does not come apart. The inside diameter of the wedge 2 is large enough to fit the tapered portion of the wedge 2, and the outside diameter is almost the same as that of the wedge receiver 1. Similar to the wedge receiver 1, FIG.
As shown in (A), the entire outer peripheral edge is chamfered,
A tongue-shaped notch 7 is formed at an opposing position on the chamfered peripheral edge. A plan view and a cross-sectional view of the cutout portion 7 are shown in FIGS. The notch 7 of the retaining ring 4 is arranged so as to face the notch 6 of the wedge receiver.

On the other hand, the wedge 2 is formed by assembling a plurality of wedge pieces to form a conical taper portion, and the PC steel material 3 is held by a hole formed at the center of the wedge so as to penetrate the holding ring 4 and receive the wedge. PC steel material 3 by fitting into the tapered hole 5 of
Has been established. In this example, a wedge composed of two wedge pieces was used. A flange 8 is formed on the outer circumference of the wedge 2 on the large diameter side, and an elongated bolt hole 14 is formed therein. Retaining ring 4
The bolt 9 screwed onto the bolt penetrates the bolt hole 14 and tightens the nut 10 to fix the wedge 2 to the retaining ring 4.

In such a fixing structure, the wedge 2 before unloading is inserted into and closely attached to the wedge receiver 1, and the holding ring 4 is also in contact with the wedge receiver 1. However, when unloading, as shown in FIG. The wedge 2 is pulled out from the taper hole 5 by re-tensioning. First, FIG. 5 (A)
As shown in, the top plate having a hole (not shown) through which the PC steel material is penetrated is equipped with two leg plates [The ram chair 11 of the type is put on the fixing tool, and the PC steel material 3 is reassembled using the hydraulic jack 12. get nervous. At this time, the holding ring 4 is lifted together with the wedge 2 and the wedge 2 is pulled out from the tapered hole 5.

Next, the bolt 9 is loosened, the wedge is expanded to the outer peripheral side of the retaining ring in the range of the bolt hole 14, and the bolt 9 is tightened again at that position. As a result, the wedge and the PC steel material are not in contact with each other, so that the support rod 13 is inserted between the retaining ring 4 and the wedge receiver 1 from the open side of the ram chair 11 and the wedge 2 is pulled out from the taper hole 5 and these are handled by hand. Hold in. Chamfering is provided on the periphery of the retaining ring 4 and the wedge receiver 1, so that the support rod 13 can be easily inserted. Further, the notches 6 and 7 provided on both sides serve as the bearing surface of the support rod 13 for easy positioning. This also prevents the support rod 13 from falling.

The supporting rod 13 may be of any type as long as it can hold the wedge 2, and the number is not limited.
As shown in Figure 2, two bolts 13A and nuts 13B with adjustable length were used. Since the length can be adjusted by turning the bolt 13A, it can be securely and easily inserted regardless of the distance between the wedge receiver 1 and the retaining ring 4.

When the tension of the hydraulic jack 12 is released in this state, the wedge 2 integral with the retaining ring 4 is supported by the support rod 13 and does not return to the tapered hole 5, but the expansion of the PC steel material 3 returns and the load is removed. Is done.

[0015]

As described above, according to the apparatus of the present invention, the unloading of the PC steel material can be performed by the same work procedure regardless of the elongation amount of the PC steel material. Since the holding ring and the supporting rod are only used as the structure of the device, it can be manufactured at a relatively low cost, and at the time of use, it is only necessary to re-tension the PC steel material and insert the supporting rod, which is extremely workable.

[Brief description of drawings]

FIG. 1 shows the device of the present invention before unloading, (A) is a plan view and (B) is a side view.

FIG. 2 shows the device of the present invention during unloading, (A) is a plan view and (B) is a side view.

3A and 3B show a wedge receiver of the device of the present invention, FIG. 3A is an overall perspective view, FIG. 3B is a plan view of a cutout portion, and FIG. 3C is a sectional view of the cutout portion.

4A and 4B show a retaining ring of the device of the present invention, FIG. 4A is an overall perspective view, FIG. 4B is a plan view of a cutout portion, and FIG. 4C is a sectional view of the cutout portion.

FIG. 5A is a perspective view of a ramchair used during unloading of the device of the present invention, and FIG. 5B is a side view of a support rod used during unloading.

FIG. 6 shows a conventional unloading device (A) before unloading,
(B) shows the state at the time of unloading.

FIG. 7 shows a conventional unloading device (A) before unloading,
(B) shows the state at the time of unloading.

[Explanation of symbols]

1 wedge receiver, 2 wedge, 3 PC steel material, 4 retaining ring,
5 Taper hole 6 Notch, 7 Notch, 8 Tsuba, 9 Bolt, 10 Nut 11 Ramchair, 12 Hydraulic jack, 13 Support rod, 13A
Bolt 13B Nut 14 Bolt hole 20 Wedge, 21 Wedge receiver, 22 Bearing plate, 23
Shim 24 PC steel, 25 ram chairs, 26 rings

Claims (5)

[Claims] 1. A unloading device for a PC steel material, wherein a PC steel material is held by a wedge composed of a plurality of wedge pieces, and the PC steel material is inserted and fixed in a wedge receiver having a tapered hole, which is held in front of the wedge receiver. The rings are arranged to face each other, and the wedge is fixed on the inner circumference of the holding ring, and a support bar is provided between the holding ring and the wedge receiver during re-tensioning due to unloading.
C steel material unloading device. 2. The unloading device for PC steel material according to claim 1, wherein the retaining ring and the wedge receiver are chamfered at their peripheral edges. 3. The unloading device for a PC steel material according to claim 1, wherein the holding ring and the wedge receiver are provided with notches serving as seat surfaces of the support rod. 4. The unloading device for PC steel material according to claim 1, wherein the length of the support rod is adjustable. 5. A method of releasing tension of PC steel material fixed by holding the PC steel material with a wedge composed of a plurality of wedge pieces and inserting the wedge into a wedge receiver having a tapered hole. It is fixed at the inner circumference of the retaining ring which is arranged in front of the receiver so as to prevent the wedge from returning to the tapered hole between the retaining ring and the wedge receiver when the wedge is pulled out from the tapered hole by re-tensioning of the PC steel material. A method for unloading PC steel material, which comprises arranging a support member to release the re-tension.