JP2634999B2 - Dismantling method of branch line tower - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of dismantling a transmitting antenna of a decker chain which is scheduled to be discontinued recently.

[0002]

2. Description of the Related Art As this kind of prior art, for example, FIG.
There is an erection method as shown in FIG. 2 and a pull-down method as shown in FIG.

The erector method shown in FIG. 12 is a method that has been used when a steel tower is constructed. In the figure, a is a steel tower, b is an aerial, and c is a branch line. In this method, an erector d is assembled on a base of a tower a by a truck crane (not shown) as shown in FIG. 1A, and this is lifted to the top of the tower a as shown in FIG. This erector d from the top
Is used to sequentially disassemble. In the drawing, e is a winch.

In the pulling-down method shown in FIG. 13, (a) is an elevation view, (b) is a plan view, and the same reference numerals as those described above denote the same components. This method is a method of cutting the branch line c in one direction out of the branch lines c in three directions and pulling down the steel tower a. As for the branch line c in the cutting direction as the first stage, the tension is reduced to some extent at the anchor portion f in advance and the tower a
(A) is tilted as shown in the figure. As a second stage, the branch line c is cut and the tower a is pulled down. The collapsed steel tower a is dismantled to a size that can be carried out by a crane (not shown) or the like.

[0005]

The erector method shown in FIG. 12 is a stable method that has a proven track record when constructing a steel tower. However, since all dismantling operations are performed at a high place, there is a danger, and workability and work efficiency are increased. Is bad.

The pulling-down method shown in FIG. 13 has a problem in a method of cutting a branch line, and it is necessary to cut all the branch lines at the same time. In addition, it is conceivable to use explosives to pull down and to bring down, but this also has various problems,
Practical application will be difficult if we do not wait for sufficient consideration in the future.

[0007]

In order to solve the above-mentioned problems, according to the present invention, a hanging stand is assembled so as to surround a base of a branch-type steel tower to be dismantled, and a branch-line retraction device is provided at the base of each branch. First, after removing the antenna, attaching a holding bracket to the steel tower in the hanging gantry, attaching an elevating device between this holding bracket and the hanging gantry, and temporarily suspending the steel tower by a small amount After cutting and removing the lower part of the tower, the tower is lowered, the branch line is pulled in by the branch line drawing-in device, and the above-mentioned operation of changing the holding bracket while the steel tower is supported by the temporary support is repeated. .

[0008]

As described above, since the present invention does not require work at a high place unlike the conventional erector method, work is safe and work efficiency is good. Also, unlike the conventional pulling method, there is no need to consider the pulling direction of the tower,
Since explosives are not used, there is an advantage that work can be performed safely and reliably.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In the figure, 1 is a branch-type transmission tower which is a transmitting antenna tower (decca tower) of a decker chain, 2 is a branch line stretched in three directions to support this tower 1, and 3 is an antenna stretched from the upper end of the tower 1 to the ground. It is.

In the present embodiment, a hanging gantry 4 is assembled so as to surround the base of the branch type steel tower 1 to be dismantled. As shown in detail in FIG.
The support 4a and the beams 4b, 4c, 4d, etc. may be used.

As shown in FIG. 1C and FIG.
A pulley type branch line retraction device 6 is provided between each branch line 2 and an anchor 5 provided on the ground. 6a is the winch.
FIG. 3 shows an example of a gripping metal fitting 7 for holding the steel tower 1, wherein 7a is a gripping metal body formed so as to be applied to both sides of the steel tower 1, 7b is a distance piece, 7b.
c is a fastening bolt, 8a is an elevating rod of an elevating device 8 to be described later, and 9 is a connection pin thereof.

In order to dismantle the tower 1, the antenna 3 shown in FIG. 1A is first removed and removed, and then the tower 1 in the suspension base 4 is attached to the tower 1 as shown in FIGS. At the same time, the holding fixture 7 is attached, and a lifting device (jacking hoist) 8 is attached between the holding fixture 7 and the hanging stand 4. Reference numeral 8a denotes an elevating rod that passes through the center of the elevating device 8, and 9 denotes a pin that connects the lower end of the rod 8a to the grip 7.

When the above-mentioned setup is completed, the lifting device 8
To lift the tower 1 by about 100 mm. In this state, the insulator (not shown) at the base of the tower 1 and the first joint 1a at the bottom of the tower 1 are dismantled as shown in FIG. Then, it is removed by the truck crane 10 or the like.

FIGS. 2A and 2B show the first section 1 of the tower 1.
a (in this embodiment, 6 m) shows a state in which the steel tower 1 has been removed. That is, from the state of FIG. 2 to the state of FIG. 5, the steel tower 1 is first lowered by 3 m which is the maximum stroke of the elevating device 8 in the present embodiment, and the holding bracket 7 is suspended and the beam 4 in the middle of the gantry 4.
Place on the temporary receiving beam 4e on c.

In this case, as the steel tower 1 descends,
(C) and the pulley type branch line retraction device 6 shown in FIG. 4 pulls the loosened portion of each branch line 2 by the winch 6a and tightens it.

Next, as shown in FIG. 6, the rod 8a is once removed from the gripping metal 7, and the rod 8a is raised by about 3 m. Then, the extension rod 8b of about 3 m is inserted between the rod 8a and the gripping metal 7. Insert and connect.

Next, as shown in FIG. 7, after temporarily removing the temporary receiving beam 4e while the tower 1 is slightly raised,
The elevating device 8 is operated to lower the steel tower 1 as shown in FIG. 1 (c) and FIG. 8, and the lower end thereof is placed on the temporary receiving support base 11. Also in this case, each branch line 2 is pulled in by the branch line drawing-in device 6 and tensioned as described above.

Next, as shown in FIG. 9, the holding fixture 7 is removed from the steel tower 1, the rod 8 a of the elevating device 8 is raised, and the holding fixture 7 is fixed above the steel tower 1 in the hanging frame 4. , And the rod 8 a is connected to the gripping metal 7.

Next, as shown in FIG. 10, the tower 1 is gas-cut at a position of about 6 m from the lower end while the tower 1 is temporarily lifted by about 50 mm by the elevating device 8, and then the cut tower 1b is removed. Thereafter, by repeating the above-described operation, the steel tower 1 can be dismantled by ground work. FIG. 11 is a flowchart of the operation described above.

[0020]

As described above, since the present invention does not require work at a high place unlike the conventional erector method, work is safe and work efficiency is good. Further, unlike the conventional pulling method, there is no need to consider the pulling direction of the tower, and since explosives are not used, there is an advantage that work can be performed safely and reliably.

[Brief description of the drawings]

FIGS. 1 (a), 1 (b) and 1 (c) are explanatory views of the method of the present invention.

FIG. 2 (a) is a partial front view showing a state where a base of a steel tower is removed by the method of the present invention, and FIG. 2 (b) is a side view thereof.

3 (a) is a front view showing a state in which a holding bracket is fastened to a steel tower by the method of the present invention, FIG. 3 (b) is a plan view thereof, and FIG. 3 (c) is a plan view of FIG. It is A sectional drawing.

FIG. 4A is a partial elevational view showing a mounting state of a branch line drawing-in device, and FIG. 4B is a partial detailed view thereof.

FIG. 5 (a) is a front view showing a state where a steel tower is lowered one step by the method of the present invention, and FIG. 5 (b) is a side view thereof.

FIG. 6 (a) is a front view showing a state in which a lifting rod is added by the method of the present invention, and FIG. 6 (b) is a side view thereof.

FIG. 7 (a) is a front view showing a state where a temporary receiving beam is removed by the method of the present invention, and FIG. 7 (b) is a side view thereof.

8 (a) is a front view showing a state where the steel tower is further lowered by the method of the present invention, and FIG. 8 (b) is a side view thereof.

FIG. 9A is a front view showing a state in which the gripping metal is rearranged by the method of the present invention, and FIG. 9B is a side view thereof.

FIG. 10 (a) is a front view showing a state where the lower part of a steel tower is cut and removed by the method of the present invention, and FIG. 10 (b) is a side view thereof.

FIG. 11 is a flowchart of the method of the present invention.

FIGS. 12A and 12B are explanatory views of a conventional erector method.

FIG. 13A is an elevation view for explaining a conventional pulling-down method, and FIG. 13B is a plan view thereof.

[Explanation of symbols]

 a Tower b Antenna c Branch line d Erector e Winch f Anchor unit 1 Branch line type tower (iron tower) 2 Branch line 3 Antenna line 4 Hanging stand 4a Column 4b, 4c, 4d Beam 4e Temporary support beam 5 Anchor 6 Branch line pull-in device 6a Winch 7 Metal fittings 7a Main body of gripping metal 8 Lifting device (jacking hoist) 8a Rod 8b Reinforcing rod 9 Connecting pin 10 Truck crane 11 Temporary support support base

Claims (1)

(57) [Claims] 1. A suspension rack is assembled so as to surround a base of a branch-type steel tower to be dismantled, a branch-wire retraction device is provided at a base of each branch line, an antenna is first removed, and then a steel tower in the suspension rack is installed. Attaching the holding bracket to, and mounting an elevating device between the holding bracket and the hanging stand, cutting and removing the lower part of the tower once the tower is lifted by a small amount, and then lowering the tower A method of dismantling a branch-type steel tower, wherein the branch line is pulled in by a branch-line drawing-in device, and the operation of changing the gripping metal while the steel tower is supported by a temporary support is repeated.