JPH0218193Y2 - - Google Patents

Description

[Detailed description of the invention] The invention relates to a jack for tensioning a prestressing steel strand in order to apply prestress to a concrete structure using a post-tension method.

Multiple PCs inserted within a concrete structure
To tension the steel strands, you must insert the PC steel strands one by one into the jack and secure them with a grip. Since steel wires are hard and difficult to bend, as the number of wires increases from 7 to 9 to 12, it becomes difficult to introduce them into the jack insertion holes at the same time, and the introduction process takes a considerable amount of time.

In order to provide a tensioning device that can solve this problem, the present invention replaces the conventional PC steel wire tensioning jack.
It has a cap at one end into which the end of the PC steel wire can be fitted, which can be inserted into the wire insertion hole and tension grip of the jack, and a guide rod having a length longer than the entire length of the jack. .

An embodiment of the device of the present invention will be described with reference to the drawings.

FIG. 1 shows the state before the PC steel stranded wire 2 is introduced into the plurality of PC steel stranded wire insertion holes 3 of the jack 1. The insertion hole 3 passes through both ends of the jack 1, and a tension grip 4 is inserted into one end of the insertion hole 3. The guide rod 5 is longer than the entire length of the insertion hole 3 of the jack 1, that is, the length of the jack 1 in the expansion/contraction direction, and both ends protrude from the jack 1 when the guide rod 5 is passed through the insertion hole 3.

A cap 6 is formed at one end of the guide rod 5, which can be fitted onto the end of the PC steel stranded wire 2. Although the outer diameter of the cap 6 part of this guide rod 5 is larger than the other parts, the cap 6 part can be inserted into the insertion hole 3 in order to introduce the PC steel wire 2 into the insertion hole 3. The inner diameter of the tensioning grip 4 can be opened larger than the outer diameter of the cap 6 so that the tensioning grip 4 can be pulled out through the tensioning grip 4.

The jack 1 of the embodiment shown in the figure is a double-acting jack, with the piston 7 on the right side of the figure protruding to the right, and the piston 8 on the left side of the figure protruding to the left.

To tension-fix PC steel stranded wire 2 with this device,
First, as shown in FIG.
It is inserted into the insertion hole 3 of the jack 1 and held by the jack 1 so that it protrudes outward from the piston 8 side. At this time, the inner diameter of the tension grip 4 on the piston 7 side is made wider than the outer diameter of the cap 6.

An annular support fitting 11 is fixed to the concrete structure around the outlet of the PC steel stranded wire 2 of the concrete structure, and the PC steel stranded wire 2 is inserted into the inner circumference of this support fitting 11 and fixed. The plate 9 is fitted. The guide rod 5 is pulled out from the insertion hole 3, and the end of the prestressed steel strand 2 pulled out from the concrete structure and the cap of the guide rod 5 are fitted. Then, lightly insert the fixing grip 10 shown in FIG. 2 between the inner surface of the insertion hole of the PC steel stranded wire 2 of the fixing plate 9 and the outer periphery of the PC steel stranded wire 2, and then Proceed from the steel toward the concrete structure along line 2 and use the guide rod 5 to connect the PC.
Guide the steel stranded wire 2 and advance it into the insertion hole 3 of the jack 1, bring the end surface of the jack 1 on the piston 8 side into contact with the support fitting 11, and insert the PC steel stranded wire 2 into the jack 1.
It protrudes outward from the piston 7 side of the piston 7 and is fixed to the jack 1 with a tension grip 4. Then move piston 7 to the right and tension wire 2 from the PC steel.

Next, the piston 8 is moved to the left to press the fixing plate 9 to the support metal fitting 11, and the fixing grip 10 is pushed into the fixing plate 9 to fix the PC steel stranded wire 2 to the fixing plate 9.

When fixing is completed, loosen the tension grip 4, move the jack 1 to the right, and remove the jack 1 from the PC steel stranded wire 2.

As described above, according to the jack of the present invention, a plurality of stranded PC steel wires can be easily inserted into the jack and through the tensioning grip using the guide rod, so tensioning work can be carried out efficiently.

[Brief explanation of the drawing]

Figure 1 is a partial cross-sectional side view of one embodiment of the jack for tensioning the PC steel stranded wire according to the present invention, showing the state before the tensioning of the PC steel stranded wire, and Figure 2 shows the state of the PC steel stranded wire from the state shown in Figure 1. FIG. 3 is a partially sectional side view showing a state in which the stranded wire is taut and fixed. 1... Jack, 2... PC steel stranded wire, 3... PC steel stranded wire insertion hole, 4... Tension grip, 5... Guide rod, 6
...Cap, 7...Piston, 8...Piston, 9...
Fixing plate, 10... Fixing grip, 11... Supporting metal fittings.

Claims (1)

[Scope of utility model registration request] A jack having a plurality of PC steel stranded wire insertion holes penetrating through both ends of the jack, a tension grip inserted into one end of the insertion hole, and a cap at one end into which an end of the PC steel stranded wire can be fitted; A jack for tensioning a PC steel stranded wire, comprising a steel stranded wire insertion hole and a guide rod that can be inserted into the tensioning grip and has a length longer than the overall length of the jack.