JP2003205514A - Apparatus for manufacturing prestressed concrete panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the tensile break of the attaching bolt of a hydraulic jack applying tensile force to a PC steel material. <P>SOLUTION: The hydraulic jacks 5 applying tensile force to the PC steel materials 8 are attached to a beam member 3b being a fixing part through pin joints 6. Accordingly, even if the axial centers of the hydraulic jacks 5 are inclined by the bending of a traction beam 7, the pin joints 6 are rotated corresponding to this inclination to prevent moment from acting on the respective attaching parts of the hydraulic jacks 5, and the tensile break of the bolts 11 and 12 of the respective attaching parts is prevented. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a prestressed concrete slab manufacturing apparatus.

[0002]

2. Description of the Related Art Prestressed concrete slabs are made by placing PC steel materials such as steel wires, stranded steel wires, and steel rods in a formwork, and applying a tensile force to these PC steel materials to form concrete in the formwork. It is manufactured by casting.

As an apparatus for producing such a prestressed concrete slab, for example, Japanese Patent Laid-Open No. 63-28436 is used.
There is one described in Japanese Patent Publication No. 7. As shown in FIG. 3, this manufacturing apparatus mounts a plurality of post-fixed beams 53a, 53b of PC steel materials 52 arranged in the form on both ends of a pair of side plates 51 which also serve as the form, and assumes one of the assumptions. Two hydraulic jacks 54 are attached to the rear surface side of the landing beam 53b, and an index beam 55 is connected to these hydraulic jacks 54. Both end plates 56 of the form are provided between the side plates 51.

One end of each of the PC steel materials 52 is fixed to the hypothetical beam 53a, and the other end of the PC steel material 52 is a connecting fitting 57 and a screw rod 58.
Is connected to the index beam 55 via the, and a tensile force is applied by pressing the index beam 55 by each hydraulic jack 54. When the pressing force of each hydraulic jack 54 reaches a predetermined value,
The screw rod 58 connected to each PC steel material 52 has a nut 59.
It is fixed to the assumed landing beam 53b by tightening the
A tension of 2 is maintained at a predetermined level. After that, the hydraulic jacks 54 and the index beams 55 are removed, and concrete is placed in the form frame formed by the side plates 51 and the end plates 56 to manufacture a prestressed concrete slab.

[0005]

In the prestressed concrete slab manufacturing apparatus as described above, the index beams 55 pressed by the two hydraulic jacks 54 are formed of the respective PC steel materials 52, as schematically shown in FIG. The reaction force of the pulling force causes the bending, and the axis of each hydraulic jack 54 slightly tilts. Therefore, a moment acts on each mounting portion of the index jack 55 of the hydraulic jack 54 and the assumed landing beam 53b which is a fixed portion,
Due to this moment, the bolts 60, 61 of each mounting portion are
A tensile force is applied to a part of these bolts 60, 61
May break.

In the manufacturing apparatus shown in FIG. 3, the two hydraulic jacks 54 are attached to the index beam 55 rather than to both ends thereof, but slightly toward the center, but in order to arrange the PC steel material 52 freely. It is desirable to attach each hydraulic jack 54 to both ends of the index beam 55. In such a case, since the span between the hydraulic jacks 54 becomes long, the index beam 55
The bending of the bolts is also increased, and the risk of breaking the bolts 60 and 61 is increased.

If the number of hydraulic jacks 54 is increased, the bending of the index beam 55 is reduced, but the hydraulic jacks 54 are
Since the increase in the number of not only hinders the free rebar arrangement of the PC steel material 52 but also increases the cost, usually, the number of the hydraulic jacks 54 is usually two.

Therefore, an object of the present invention is to prevent tensile breakage of a mounting bolt of a hydraulic jack that applies a tensile force to a PC steel material.

[0009]

In order to solve the above-mentioned problems, the present invention fixes one end side of a PC steel material to be reinforced in the formwork on both sides of the formwork in which concrete is placed. A fixed beam and an index beam for indexing the other end side of the PC steel material are arranged so as to face each other, and a plurality of hydraulic jacks are attached between the index beam and the fixed portion to separate the fixed beam from the fixed beam. In the prestressed concrete slab manufacturing apparatus for pressing the PC steel material with a tensile force, the hydraulic jacks are attached to the fixing portion or the index beam through a pin joint.

That is, by attaching a hydraulic jack for applying a tensile force to PC steel through a pin joint,
Even if the axis of the hydraulic jack is tilted due to the bending of the index beam, the pin joint will rotate in response to this tilt, preventing a moment from acting on the mounting part of the hydraulic jack, and applying a tensile force to the bolt of the mounting part. No, the bolt was not broken.

A prestressed concrete slab is constructed at a construction site by making the fixed beam and the fixed portion to which the hydraulic jacks are attached into an integral steel frame and making the manufacturing apparatus portable with the steel frame. It is possible to eliminate the problem of manufacturing and transporting a prestressed concrete slab of a size and weight that is difficult to transport by eliminating the need to transport it to the construction site.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, in this prestressed concrete slab manufacturing apparatus, a pair of beam members 3a and 3b are attached to both ends of a pair of pillar members 2 on the outer peripheral side of a rectangular formwork 1 on which concrete is placed. The rectangular steel frame 4 is arranged, two hydraulic jacks 5 are attached to the rear surface side of the beam member 3b which is the fixed portion through the pin joints 6, and the index beams 7 are connected to these hydraulic jacks 5. It was done.

The index beam 7 is removable, and the disassembled hydraulic jack 5, index beam 7, steel frame 4 and the like can be transported to a construction site for assembly. The steel frame 4 is an assembling type, and can be transported in a state of being disassembled into the pillar member 2 and the beam members 3a and 3b and assembled at the construction site. If the steel frame 4 has such a small size that it can be mounted on a transportation vehicle, it may be transported as it is.

The PC steel material 8 arranged in the mold 1 is
One end side is fixed to the beam member 3a as a fixed beam with the fixing tool 9, and the other end side is fixed to the index beam 7 with the fixing tool 10 through a through hole (not shown) provided in the beam member 3b.
A pulling force is applied by pressing the index beam 7 with each hydraulic jack 5 in a direction away from the beam member 3a.

As shown in the enlarged view of FIG. 2, the hydraulic jack 5 is attached at its base end side to the index beam 7 with a bolt 11, and has a clevis 6a provided at the rod tip and a bolt 12 to the beam member 3b. The pin joint 6 is formed by the pin 6b provided on the attached metal fitting 13. Each of the bolts 11 and 12 is provided with four bolts.

Therefore, as described above, the PC steel material 8
Even if the index beam 7 is bent due to the reaction force of the pulling force of the pin jack 6 and the shaft center of the hydraulic jack 5 is tilted, the pin joint 6
Does not act on the mounting portion of the hydraulic jack 5 to the index beam 7 and the mounting portion of the hydraulic jack 5 to the beam member 3b through the pin joint 6, and the bolts 11 and 12 of these mounting portions are not affected. Does not break in tension.

In each of the above-described embodiments, the base end side of the hydraulic jack is attached to the index beam and the tip end side is attached to the beam member which is the fixed portion via the pin joint, but the hydraulic jack is attached in the opposite direction. May be.

[0018]

As described above, in the apparatus for manufacturing a prestressed concrete slab of the present invention, a hydraulic jack for applying a tensile force to a PC steel material is attached to a fixed portion via a pin joint, and the hydraulic jack is bent by bending the index beam. Even if the shaft center is tilted, the pin joint rotates in response to this tilt so that moments do not act on the mounting parts of the hydraulic jack, so tensile force is applied to some of the bolts at these mounting parts. It is possible to prevent the tensile breakage of the bolt.

Further, the fixed beam and the fixed portion to which the respective hydraulic jacks are attached are provided in an integral steel frame,
By making the manufacturing equipment portable with this steel frame, it is possible to manufacture a prestressed concrete slab at the construction site and eliminate the need to transport it to the construction site. The problem of transportation can be solved.

[Brief description of drawings]

FIG. 1 is a partially omitted plan view showing an embodiment of a prestressed concrete slab manufacturing apparatus.

FIG. 2 is an enlarged plan view of an essential part of FIG.

FIG. 3 is a partially omitted plan view showing a conventional prestressed concrete slab manufacturing apparatus.

FIG. 4 is a schematic diagram illustrating bending of an index beam.

[Explanation of symbols]

1 formwork 2 pillar members 3a, 3b Beam member 4 steel frame 5 hydraulic jack 6 pin joint 6a clevis 6b pin 7 Index beams 8 PC steel 9,10 Fixing tool 11, 12 volt 13 metal fittings

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Morika Kushida             1-12-19 Kitahori, Nishi-ku, Osaka City Stock Association             Kurimoto Ironworks F term (reference) 4G058 GA01 GB02 GF08 GF12 GF13                       GF17

Claims (2)

[Claims] 1. A fixed beam for fixing one end side of a PC steel material arranged in the formwork and an index beam for indexing the other end side of the PC steel material on both sides of the formwork in which concrete is cast. A prestressed concrete slab that is arranged so as to face each other and is pressed in a direction away from the fixed beam with a plurality of hydraulic jacks attached to the index beam between the index beam and the fixed portion to apply a tensile force to the PC steel material. 2. The manufacturing apparatus for a prestressed concrete slab according to claim 1, wherein each of the hydraulic jacks is attached to the fixing portion or the index beam through a pin joint. 2. The prestressed concrete according to claim 1, wherein the fixed beam and the fixed portion to which the hydraulic jacks are attached are made of an integral steel frame, and the manufacturing apparatus is portable with the steel frame. Plate manufacturing equipment.