JPH0246977Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] This invention incorporates PC into the formwork for concrete piles in order to produce ready-made concrete piles containing PC steel wire.
This invention relates to a tensioning device that stretches and supports a steel wire and applies tension to the PC steel wire.

[Prior Art] Fig. 2 is a vertical cross-sectional view schematically depicting an example of a ready-made concrete manufacturing apparatus containing PC steel wires.

1 is the formwork that forms the side of the concrete pile,
A pair of PC steel wire mounting plates 3, 4 forming both end faces of the formwork are provided. Between the above pair of PC steel wire mounting plates 3 and 4, multiple (6 in this example)
The PC steel wire 5 is stretched.

The PC steel wire mounting plate 3 in this example is on the drive side,
It is pulled to the left in the figure by the hydraulic cylinder Sy.

On the other hand, the PC steel wire mounting plate 4 is on the anchor side,
A screw rod 6 is fixed.

The screw rod 6 is a frame member 7 that serves as an anchor.
and the nut 8 is screwed together. FIG. 3 shows an enlarged appearance of the part.

Reference numeral 9 indicated by a virtual line is a core member for forming a hollow concrete pile.

In the preparation process before pouring concrete into the formwork 1, no particularly large force is required to turn the nut 8 unless pressure oil is supplied to the hydraulic cylinder Sy.

After adjusting the position of the PC steel wire mounting plate 4 by turning the nut 8, supply pressure oil to the hydraulic cylinder Sy.
When tension is applied to the PC steel wire 5, the nut 8 cannot be turned with normal force.

[Problems to be solved by the invention] After concrete is poured and hardened while operating the cylinder Sy and maintaining tension on the PC steel wire 5, the nut 8 must be loosened. However, at this time, unless a large rotational force is applied to the nut 8, it will not loosen.

In the case of a normal-sized pre-made concrete pile, the nut 8 will not loosen unless two people turn it using a wrench with a length of about 2 meters.

On the other hand, if the related members were ideally rigid bodies, then loosening the nut 8 a little would cause the required rotational force to decrease rapidly.

However, in reality, each of the related members has elasticity and bends. In particular, the PC steel wire 5 is subjected to large tension and is elastically deformed in the elongation direction. For this reason, the torque required for turning the nut 8 will not be significantly reduced unless the nut 8 is rotated about 2 times in the loosening direction. If you don't rotate the nut, you won't be able to turn it with one person's power.

It takes two people to rotate a long-handled spanner twice, and the amount of effort and time required cannot be ignored. This is one of the keys to rationalization and cost reduction in the production of ready-made concrete piles with pre-cast steel wire.

The present invention was developed in view of the above-mentioned circumstances, and its purpose is to quickly and easily support the PC steel wire mounting plate to the frame by one worker. The purpose of this invention is to provide a PC steel wire tensioning device that can loosen a fixed nut.

[Means for solving the problem] The device of the present invention created to achieve the above purpose consists of a steel wire mounting plate for attaching a PC steel wire to be buried in a prefabricated concrete pile, and a central part of the steel wire mounting plate. applied to a PC steel wire tensioning device that is provided with a male threaded rod fixed at right angles to a plate surface, a frame member provided with a through hole through which the male threaded rod is inserted, and a nut screwed into the threaded rod, A disk-shaped member is provided with a nut hole that engages with the nut, a sheave-shaped groove is provided around the disk-shaped member, and a rope is fixed at one end to the disk-shaped member. It is characterized in that it is configured so that it can be wound around the sheave-like groove.

[Operation] According to the above configuration, when the end of the rope wound around the sheave-like groove is pulled up with a winch (or hoist), the circumferential plate-like member is forcibly turned by power, and the nut engaged with it is rotated. It is rotated powerfully. In this case, if the rope is wrapped around the sheave groove more than two times, the nut will be rotated about two times, making it easier for one worker to turn the nut.

[Embodiment] FIG. 1 is an exploded perspective view showing one embodiment of the present invention.

The PC steel wire mounting plate 4, the PC steel wire 5, the screw rod 6, the frame member 7, and the nut 8 are the same structural members as in the conventional example shown in FIGS. 2 and 3.

Hexagonal through hole (nut hole) that engages with nut 8
A disc-shaped member 11 having a diameter 11a is constructed, and a sheave-shaped groove 11b is formed around the disc-shaped member 11. 11c is a through hole formed by stealing meat to reduce weight.

One end 12a of the wire rope 12 is fixed to the bottom of the sheave-like groove 11b.

With the nut 8 screwed into the threaded rod 6 and tension applied to the PC steel wire 5, the PC steel wire 5 is buried in concrete (not shown) and after the concrete has solidified, the present embodiment Nuts using equipment 8
To loosen the nut hole 11a of the disc-shaped member 11.
is engaged with the nut 8, and the wire rope 12 is wound around the sheave-like groove 11b.

In order to make the diagram easier to read, Figure 1 depicts the state in which the wire rope 12 is wound around the sheave-like groove less than once (more specifically, approximately 3/4 times); however, when implementing the present invention, , the number of windings can be arbitrarily selected. In order to fully demonstrate its practical value, the length of the wire rope must be commensurate with the lifting height of the crane (including a hoist) that can be used in the workplace (ready-made concrete pile manufacturing factory) where the device of this invention is used.
It is convenient to wrap it around the sheave-like groove 11b.

After preparing as described above, when the end of the wire rope 12 is hoisted by a crane as shown by the arrow P in the figure, the disc-shaped member 11 is rotated in the counterclockwise direction arrow L in the figure and the nut engaged therewith is rotated. 8 is turned in the loosening direction.

According to the device of this embodiment, as long as a crane or a hoist is available, there is no need to newly install a separate drive source (for example, a hydraulic cylinder or a hydraulic motor), and the nut 8 can be moved using an existing crane or the like. I can relax.

[Effects of the invention] As explained above, according to the PC steel wire tensioning device for ready-made concrete piles of the present invention, the PC steel wire mounting plate can be supported quickly and easily by one worker. Nuts can be loosened, and in particular, nuts can be loosened with a large turning force using an existing crane or the like without the need to install a new power device.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view showing one embodiment of the present invention. FIG. 2 is a sectional view of a conventional ready-made concrete pile structure, and FIG. 3 is a partial external view of the same. 5...PC steel wire, 6...screw rod, 8...nut,
11... Disc-shaped member, 11a... Nut hole, 11
b... Sheave-like groove, 12... Wire rope.

Claims (1)

[Scope of utility model registration request] A steel wire mounting plate for attaching the PC steel wire to be buried in a prefabricated concrete pile, a male threaded rod fixed at right angles to the plate surface in the center of the steel wire mounting plate, and a through hole for inserting the male threaded rod. In a PC steel wire tensioning device that includes a frame member and a nut that is screwed into the threaded rod, a disc-shaped member is provided with a nut hole that engages with the nut, and a periphery of the disc-shaped member is configured. A sheave-shaped groove is provided in the disc-shaped member, and a rope having one end fixed to the disc-shaped member can be wound around the sheave-shaped groove.
PC steel wire tensioning device for ready-made concrete piles.