JPH0244966Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention relates to a PC steel wire tensioning device that is fixed to the end of a pretension bench in order to make pretensioned concrete products.

(Conventional technology) In order to make products with pretensioned concrete, a formwork of the desired shape is built on a pretension bench built on the factory site, and then
Tension is applied through the PC steel wire, concrete is poured, the elastic elongation of the PC steel wire is fixed as it hardens, and the concrete is removed from the formwork.

As a PC steel wire tensioning device, for example, a device as shown in Fig. 7 is generally used. P in the figure is the end of the PC steel wire passed through the formwork, and the wedge-type fixing device 1 is used to
It is fixed in each hole of the fixing plate 2. The lower edge of the fixing plate 2 slides on the sliding table 3.

The tension mechanism that slides the fixing plate 2 and generates the required tension on each PC steel wire P includes a post 4, a jack 5, and a jack 5 fixed to the upper surface of the pretension bench B.
They include a traction plate 6, a traction bar 7, a traction plate sliding base 8, and the like.

Since the traction rod 7 passes through the through hole of the post 4, the traction plate 6 and the rod 7 pull each PC steel wire P through the fixing plate 2 by pushing out the jack 5.
If you use a hydraulic jack, you can calculate the internal stress of each PC steel wire from the oil pressure gauge.

(Problem to be solved by the invention) Since each PC steel wire is usually stretched parallel to the top surface of the bench, the fixing plate 2 in FIG. It has settled at a height of .
Therefore, if the post 4 is strongly towed to give it the required elastic elongation, the post 4 will receive a strong pushing down force due to the moment of the reaction force.

As a result, the structure of the post 4, its fixing mechanism, and the structure of the bench itself are all very strong, which is fine for conventional factory equipment, but there is room for improvement as a removable bench tensioning device developed by the applicant. He focused on a certain point and took this as the purpose of his invention.

(Means for solving the problem) This invention uses a tensioning device attached to the end of the bench to tension the PC steel wire passed through the concrete forming form on the pretension bench.
Multiple boards lined up one after the other on the bench outside the end plate of the formwork, each PC protruding from the top of the formwork.
A guide plate with a guide hole and its support mechanism, in which a steel wire is passed through a through-hole in each plate, bent downward one after another and directed toward the top of the bench, and a rectangular hole fixed face down on the top of the end of the bench. The frame is a flat steel frame, and the opposing surfaces of the vertical members on both sides along the center line of the bench have a traction guide frame with horizontal grooves, and fixing holes for the PC steel wires that pass through the above-mentioned through holes, and both ends are attached to the horizontal grooves on both sides. and a traction horizontal frame that can be moved in parallel in the tensioning direction of the PC steel wire, and has a space for inserting a jack between the formwork side cross member of the guide frame and the traction horizontal frame. This is a PC steel wire tensioning device.

(Function) This idea lowers the position of the jack 5 near the top surface of bench B in the example shown in Fig. 7 by pulling down the end of the PC steel wire that has come out of the formwork, and the traction reaction force is lowered. In addition, the slide plate 8 for the traction plate and the post 4 are made into an integrated flat steel frame, so that they can be stably attached to the bench.

That is, a plurality of guide plates with guide holes (through holes) arranged as required are erected on the bench outside the end plate of the formwork.
As each PC steel wire coming out from the top of the formwork passes through the through holes in each plate in sequence, it is directed toward the top of the bench. The ends of each steel wire are then fixed to a horizontal frame for traction within a flat guide frame laid down on the top surface of the bench. When a jack is inserted between the guide frame cross member and the towing horizontal frame and the horizontal member is pushed, the towing horizontal frame moves while being restrained from floating by the horizontal groove.
The PC steel wire is stretched to the required length to create the required tension.

(Example) Figure 1 shows a pretension system to which this idea is applied.
A panoramic view of the bench is shown, and FIG. 2 shows an embodiment of this invention.

B is the bench, M is the formwork, N is the end plate, P
is PC steel wire. The guide plate with guiding holes unique to this invention is numbered 10, the towing guide frame is numbered 11, its support mechanism is numbered 20, and the horizontal frame for traction is numbered 12. 3rd, 4th
The figure is a detailed view of the guide frame 11 and the towing horizontal frame 12, and Figures 5 and 6 are the guide plate 10 with guide holes and its support mechanism 2.
0 is a detailed diagram of 0.

The guide frame 11 shown in Figures 3 and 4 is a steel frame made up of four rectangular pieces: left and right vertical members 11a, 11a oriented along the center line of the bench, a horizontal member 11b near the formwork, and a horizontal member 11d on the opposite side. , the vertical members 11a, 11a are shaped cross sections in this case, so the opposing surfaces are the horizontal grooves 11c,
It's becoming 11c. Anti-friction material was pasted on the ceiling of horizontal groove 11c. Applying a resin lining material will significantly reduce friction.

The horizontal member 11b has a PC attached to the lower part of the formwork.
A large number of receiving holes 13 are provided to receive the steel wire P, so that even if the product changes, it can be passed through any of the holes. The PC steel wire P that has reached the towing horizontal frame 12 through the guide tube 13a from the receiving hole 13 has its tip peeking into the fixing hole 15 through the receiving hole 14 and the guide tube 14a, and is fixed by the wedge-type fixing device 16. be done.

On the other hand, the PC steel wire P stretched at a high position of the formwork is directly fixed to the upper fixing hole 15a of the horizontal frame 12 for traction (see FIGS. 2 and 4). Although shown only in Fig. 3, the jack 5 includes the horizontal member 11b and the horizontal frame 12 for towing.
and the steel wire P by pushing them apart.
towing. For a 50-60m bench, a towing stroke of 300mm is sufficient.

In this embodiment, the distance between the towing horizontal frame 12 and the horizontal member 11d is adjusted by using a high-tensile threaded rod 18 so that the jack 5 can be removed after applying the required tension to the steel wire P.
A mechanism has been added to secure it with a nut. 1
7 is a mounting hole to the bench.

Next, an embodiment of the guide plate 10 with guide holes and its support mechanism 20 will be described with reference to FIGS. 5 and 6. Information board 1
0 is a rectangular flat plate with through holes 10a at required positions, and a hanger 19 is attached to the upper end so that it can be replaced at any time. Of course, the position of the through hole 10a is
The guide plates farther from the formwork are lowered, and the PC steel wires P passed through them are bent downward one after another. The arrangement of holes 10a is different for many types of products.
The guide plate 10 can be adjusted to correspond to the position of the PC steel wire, and the guide plate 10 can be easily replaced because it is installed in a drop-in manner. Since the outer periphery of the PC steel wire is smooth, the wear of the through hole 10a is small.

The support mechanism 20 of the guide plate 10 is box-shaped in this example without front and rear walls, and is bolted onto the bench through bolt holes 21. Each guide board 1 is on the left and right inner walls.
An introduction groove material 22 into which the 0 is dropped from above is attached, and a receiving groove material 23 is attached to the bottom plate. 24 is a reinforcing plate.

Pretension bench B in Figure 1 is on the right side.
The tension side of the PC steel wire P, the left side, is the anchoring side, and the traction guide frame 11 of this invention and the support mechanism 20 containing the new inner plate with guide holes are attached to the tension side. On the fixing side, the end of the steel wire P may be fixed by a conventional fixing mechanism. However, in this embodiment, the steel wire P is directed diagonally downward using a guide plate with a guide hole and a support mechanism 20 similar to those on the tension side. The mechanism that fixes the end of the line is also
In the drawings, the reference numeral 8 is simply attached, but the traction horizontal frame 12 in FIGS. 3 and 4 is a rectangular steel frame with fixed cross members to reduce the moment of traction force.

Although one embodiment has been described above, this invention can be varied and applied in a variety of ways depending on the implementation conditions and well-known techniques of the designer without changing its gist. The support mechanism may be modified so that each guide plate can swing around its lower end only at the end of the towing stroke, when the friction between the through hole and the PC steel wire becomes stronger. You are free to use anti-friction materials, etc.
Of course, friction is a problem for calculating the traction force, and wear on the guide plate through holes and the ends of the PC steel wire is practically not a problem.

(Effects of the invention) This invention was developed by using a PC on a pretension bench.
When forming concrete products, we abandon the conventional wisdom that the pulling direction of the PC steel wire stretched parallel to the bench surface is limited to the horizontal direction, and simplify the tensioning device by pulling it diagonally downward. achieved and suitable for portable pretension benches.
It can be used as a PC steel wire tensioning device.

A complicated mechanism can be considered to orient each of the many PC steel wires placed diagonally downward in the cross section of the product, but
This idea is the simplest and easiest to change and apply mechanism by arranging multiple guide plates with guide holes one behind the other and lowering the positions of the guide holes one after another.

The terminals of each PC steel wire are fixed to the traction horizontal frame that slides in the inner horizontal groove of the traction guide frame, which is a flat steel frame, so a jack is inserted between this horizontal frame and the steel frame cross member. For example, the PC steel wire end facing diagonally downward can be easily towed along the bench surface without fear of floating up. This reduces the moment of traction reaction force, and since the traction guide frame is a flat steel frame, it is sufficient to simply bolt it onto the bench.

In order to avoid the transportation problems of transporting long prestressed concrete products from the factory to the construction site, the method of assembling portable pretension benches on site is about to enter into practical use. will be added to the sectional bench,
The effect of this idea can be extremely significant.

[Brief explanation of the drawing]

Figure 1 shows a pretension system applying this idea.
An elevational view of an example of a bench, Fig. 2 is an explanatory view of an embodiment of this invention, Figs. 3 and 4 are a plan view and a vertical sectional view of the towing guide frame of the above embodiment, and Figs. 5 and 6 are also equipped with guide holes. A longitudinal cross-sectional view, a plan view, and FIG. 7 of the guide plate and its support mechanism are explanatory diagrams of the prior art. 10... Guide plate with guiding holes, 11... Towing guide frame, 12... Traction horizontal frame, 20... Guide plate support mechanism.

Claims (1)

[Scope of Claim for Utility Model Registration] In a tensioning device installed at the end of a pretension bench to tension a prestressed steel wire passed through a concrete forming form, Multiple plates lined up one after the other, each extending from the top of the formwork.
A guide plate with a guide hole and its support mechanism, in which the PC steel wire is passed through the through hole of each plate material, bent downward one by one and directed near the top of the bench, and a rectangular guide plate fixed face down on the top of the end of the bench. It is a flat steel frame, and the opposing surfaces of the vertical members on both sides along the center line of the bench have a traction guide frame with horizontal grooves, and fixing holes for the PC steel wires that passed through the above-mentioned through holes, and both ends are attached to the above-mentioned horizontal grooves on both sides. and a traction horizontal frame that can be moved in parallel in the tension direction of the PC steel wire, and a space for inserting a jack between the formwork side cross member of the guide frame and the traction horizontal frame. Features: PC steel wire tensioning device.