JP3922945B2 - Prestressed concrete plate manufacturing equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for manufacturing a prestressed concrete plate, and more particularly to an apparatus for manufacturing a prestressed concrete plate that can release the tension of a PC steel material that has been arranged without using a large-capacity hydraulic jack.
[0002]
[Prior art]
When producing prestressed concrete slabs, PC steel materials such as steel wires, steel stranded wires, and steel bars are placed in the formwork, and both ends of these PC steel materials are tension-fixed to a frame provided on the outer periphery of the formwork. In this state, concrete is placed in the mold, and after the concrete is hardened, the tension of the PC steel material is released.
[0003]
Apparatus for manufacturing prestressed concrete panel provided on the plant, on the rear side of the frame beam portion at both ends of the PC steel material is tensioned fixed, provided traction beams separate one end of the PC steel material are connected, the towing beam In many cases, a tension force is applied to each PC steel material by pressing it to the rear side of the gantry beam with a large-capacity hydraulic jack. In such a manufacturing apparatus, even after the concrete is hardened, the tension force of each PC steel material is released at once by loosening the pressing force of the hydraulic jack.
[0004]
On the other hand, in order to eliminate the need to transport a prestressed concrete plate having a size or weight that is difficult to transport, it has recently been desired to manufacture a prestressed concrete plate at a construction site. When prestressed concrete plates are manufactured at the construction site in this way, it is dangerous to apply tension to each PC steel using a large capacity hydraulic jack at once. In many cases, a tension force is applied to the PC steel material one by one and both ends thereof are fixed to the gantry beam portion with a fixing tool.
[0005]
[Problems to be solved by the invention]
In the prestressed concrete plate manufacturing apparatus that applies the tension of the PC steel as described above, there is a problem that it is difficult to release the tension of each PC steel after the concrete is hardened. In other words, at present, the end of each tensioned PC steel material is clamped, a tensile force is applied by a manual hydraulic jack, etc., and the tensioning force is released after removing the fixing tool to the gantry beam. Therefore, there is a problem that it is very time-consuming and has a risk to remove the fixing tool from the strained PC steel.
[0006]
Then, the subject of this invention is providing the manufacturing apparatus of the prestressed concrete board which can cancel | release the tension | tensile_strength of PC steel materials easily and safely, without using a large capacity hydraulic jack.
[0007]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a beam portion for tension-fixing both ends of a PC steel material arranged in a mold on the outer peripheral side of a mold on which concrete is placed, and both these beams An apparatus for manufacturing a prestressed concrete plate provided with a frame-like gantry comprising column portions that receive a reaction force of a tension force of a PC steel material acting as a compression axial force, and imparting a tension force to each PC steel material one by one In this embodiment, the column portion is provided with an expansion / contraction mechanism that can be contracted and operated by the action of the compression axial force, and a configuration is adopted in which the tension force of the PC steel material is released by operating the expansion / contraction mechanism.
[0008]
That is, each of the tensioned PC steel members is provided with an expansion / contraction mechanism that can be contracted and operated by the compression axial force of the reaction force at the column portion of the pedestal that receives the reaction force of the tension force of the PC steel material. These tensions can be easily and safely released without touching.
[0009]
As the expansion / contraction mechanism, a fitting portion is formed that is slidably fitted in the axial direction to the column portion between the two beam portions, and in which a hollow chamber is formed in which the volume is expanded and contracted with the sliding in the axial direction. Providing a flowable insert into the hollow chamber, and providing an openable and closable outlet that allows the flowable insert filled in the hollow chamber to flow out.When the outlet is opened, the compression axial force is It is possible to employ one in which the flowable insert flows out of the hollow chamber due to the action and the shrinking operation is performed. In addition, sand, water, a steel ball, etc. can be used as a fluid insert.
[0010]
Further, as the expansion / contraction mechanism, a wedge between the two beam portions is inserted / removed in a direction orthogonal to the axial direction and pressed to the insertion side by a screw member, and both sides where the wedge is interposed are interposed. A guide portion that guides the relative movement of the column portion in the axial direction is provided, and when the screw member is loosened, the wedge is retracted to the extraction side by the action of the compression axial force, and the contraction operation is performed. Can also be adopted.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 and 2 are the first embodiment. As shown in FIG. 1, this prestressed concrete plate manufacturing apparatus has a rectangular frame shape with a pair of beam members 2a and 2b and two column members 3 on the outer peripheral side of a mold 1 on which concrete is placed. The both ends of each PC steel material 5 arranged in the mold 1 are tension-fixed between both beam members 2a, 2b, and the reaction force of the tension force of each PC steel material 5 is This is received as a compression axial force of the column member 3. Although illustration is omitted, the PC steel material 5 is arranged in a plurality of stages in the vertical direction.
[0012]
This manufacturing equipment is used to manufacture prestressed concrete slabs at the construction site. Each PC steel 5 is tensioned with a small manual hydraulic jack, one by one without using a traction beam pressed by a large hydraulic jack. And both ends thereof are fixed to the beam members 2 a and 2 b by the fixing tool 6.
[0013]
Each of the beam members 2a and 2b is formed by welding a connecting portion 8 also formed of a square pipe at right angles to both ends of a beam portion 7 formed of a square pipe. Each column member 3 is also formed of a square pipe, and one end side thereof is connected and fixed to each connecting portion 8 of the beam member 2a with a bolt, and is compressed between the other end side and each connecting portion 8 of the beam member 2b. An expansion / contraction mechanism 9 that is contracted and operated by the action of an axial force is provided.
[0014]
As shown in FIG. 2, the expansion / contraction mechanism 9 slidably fits the end portion of the column member 3 formed by the square pipes and the connecting portion 8 of the beam member 2b, and the square pipes are fitted to each other. A hollow chamber 11 in which the pillar member 3 side is partitioned by the partition plate 10 and the beam member 2b side is partitioned by the square pipe of the beam portion 7 is formed in the inside, and the bag-containing sand 12 is formed in the hollow chamber 11. A hole 14 closed with a stopper 13 is provided on the bottom side of the hollow chamber 11.
[0015]
Therefore, after the concrete placed in the mold 1 is hardened, the plug 13 is removed and the bag of the sand 12 is broken, so that the sand 12 filled in the hollow chamber 11 by the action of the compression axial force becomes the hole 14. The hollow chamber 11 that has flowed out of the container 12 and released the filling pressure of the sand 12 contracts in the axial direction, and the tension of each PC steel material 5 is released collectively.
[0016]
In this embodiment, the sand 12 in the bag is used as the fluid insert into the hollow chamber 11, but water, steel balls, or the like can also be used. In the case where a steel ball is used, the hollow chamber 11 may be directly filled without entering the bag.
[0017]
3 and 4 show a second embodiment. The prestressed concrete plate manufacturing apparatus has the same basic configuration as that of the first embodiment, except for the expansion and contraction mechanism 9.
[0018]
As shown in FIGS. 4 (a) and 4 (b), the telescopic mechanism 9 of this embodiment has an end face of a pillar member 3 formed of a square pipe obliquely formed and closed, and is also formed of a square pipe. Between the connecting portion 8 of the beam member 2b whose end face is closed, a wedge 15 that is inserted and removed in the direction orthogonal to the axial direction is pressed to the lower insertion side by a bolt 16 that is a screw member. Also, pipes 3 are respectively formed on the upper surface of the end of the column member 3 and the upper surface of the connecting portion 8 so as to be slidable with each other, and guide the relative movement of the column member 3 and the beam member 2b in the axial direction. A pair of guide members 17a and 17b are attached. The bolt 16 is screwed to the guide member 17b side through a long hole 18 provided on the guide member 17a side.
[0019]
Therefore, after the concrete placed in the mold 1 is hardened, the bolt 16 is turned to the loose side, so that the wedge 15 escapes upward by the action of the compression axial force, and the column members 3 on both sides of the wedge 15. While the connecting portion 8 is guided by the pair of guide members 17a and 17b, the two end surfaces approach each other in the axial direction, and the tension of each PC steel material 5 is released at once.
[0020]
FIG. 5 shows a modification of the second embodiment. In this modification, the pair of guide members 17a and 17b are formed of square tube members that are fitted and fixed to the outer periphery of the end portion of the column member 3 and the outer periphery of the connecting portion 8, respectively, and these are slidably fitted. It is. Similarly to the second embodiment, the bolt 16 is screwed to the guide member 17b side through a long hole 18 provided on the guide member 17a side.
[0021]
In each embodiment mentioned above, although the expansion-contraction mechanism for canceling the tension | tensile_strength of PC steel materials was provided in the connection part of a column member and a beam member, you may provide in the middle of a column member.
[0022]
【The invention's effect】
As described above, the prestressed concrete plate manufacturing apparatus of the present invention is provided with an expansion / contraction mechanism that can be contracted and operated by the compression axial force of the reaction force in the column portion of the pedestal that receives the reaction force of the tension force of the PC steel material. By operating this expansion / contraction mechanism after the concrete placed in the mold is hardened, these tensions can be easily and safely released without touching each tensioned PC steel. Can do.
[Brief description of the drawings]
FIG. 1 is a plan view showing a prestressed concrete plate manufacturing apparatus according to a first embodiment. FIG. 2 is an enlarged front view showing an expansion and contraction mechanism section of FIG. 1. FIG. 3 is a prestressed concrete plate according to a second embodiment. 4 is a plan view showing the expansion / contraction mechanism part of FIG. 3 in an enlarged manner, and FIG. 5b is a front view of the expansion / contraction mechanism part of FIG. 3. FIG. [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Formwork 2a, 2b Beam member 3 Column member 4 Base 5 PC steel material 6 Fixing tool 7 Beam part 8 Connection part 9 Expansion mechanism 10 Partition plate 11 Hollow chamber 12 Sand 13 Plug 14 Hole 15 Wedge 16 Bolts 17a, 17b Guide member 18 Long hole

Claims (3)

On the outer periphery of the formwork on which concrete is placed, a beam part that tensions and fixes both ends of the PC steel material arranged in the formwork, and the reaction force of the tension force of the PC steel material acting between these beam parts In a prestressed concrete plate manufacturing apparatus that provides a frame-like gantry comprising a column portion that receives as a compression axial force, and applies tension to each PC steel material one by one, the column portion is subjected to the action of the compression axial force. An apparatus for producing a prestressed concrete plate, characterized in that an expansion / contraction mechanism capable of shrinking operation is provided, and the tension force of the PC steel material is released by operating the expansion / contraction mechanism. The expansion / contraction mechanism is fitted to the column portion between the beam portions so as to be slidable in the axial direction, and a fitting portion is provided in which a hollow chamber is formed in which the volume is expanded and contracted with the sliding in the axial direction. The hollow chamber is filled with a flowable insert, and an openable and closable outlet is provided to allow the flowable insert filled in the hollow chamber to flow out. When the outlet is opened, the compression axial force acts. The apparatus for producing a prestressed concrete plate according to claim 1, wherein the flowable insert flows out of the hollow chamber and the shrinking operation is performed. The expansion / contraction mechanism includes a wedge that is inserted / removed in a direction orthogonal to the axial direction of the column portion between the beam portions and pressed to the insertion side by a screw member. A guide portion for guiding relative movement in the axial direction is provided, and when the pressing of the screw member is loosened, the wedge is retracted to the extraction side by the action of the compression axial force, and the contraction operation is performed. Item 2. A prestressed concrete plate manufacturing apparatus according to Item 1.

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