JPH0671431A - Dividing method for cutting sheet pile in longitudinal direction - Google Patents

Abstract

PURPOSE:To prevent the development of a bending caused by heat strain by fitting plural jigs attaching rollers at the tip parts to insert a sheet pile in a self-travelling type gas cutter and cutting off while preheating along a gas cutting line. CONSTITUTION:The gas cutting device 4 is laid on the sheet pile 1 to be cut. A jig 5 having the cutting copying function and attaching the rollers 7 at the tip part is fixed by adjusting the angle so as to match to the size of the sheet pile 1. The preheating is executed with two preheating torches 6 from the tip part of the sheet pile 1 and at the same time, the sheet pile 1 is cut with a cutting torch 11. For example, in the case the length of the sheet pile 1 is 17m, the bending after cutting is 4.7mm so small as to obtain the precision, which the correction of bending is unnecessary. Therefore, the improvement of the working capacity, cutting precision and the product quality can be achieved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cutting a sheet pile at the time of manufacturing a steel pipe sheet pile with a sheet pile used for civil engineering work or landfill work.

[0002]

2. Description of the Related Art FIG. 5 is a view showing a cutting method by a conventional self-propelled gas cutting machine 2 when cutting a sheet pile 1 vertically. A sheet pile that is attached to a steel pipe as a joint of a steel pipe sheet pile is usually divided into two parts in the longitudinal direction by gas or the like and attached to the steel pipe by welding or the like. In the vertical division cutting operation of the sheet pile, when the self-propelled gas cutting machine 2 cuts the gas at a stretch as shown in FIG. 5, the sheet pile 1 is bent due to distortion due to heat. At this time, the copying of the cutting line 3 is performed by the operator during the cutting while manually adjusting the cutting machine 2.
However, when such cutting is performed, the bending due to thermal strain after cutting is severe, and it is almost impossible to correct.

Therefore, conventionally, in order to prevent bending at the time of cutting, water is filled in the water tank to immerse the sheet pile (to accelerate heat dissipation). Next, as shown in FIG. 2, the cutting lines 3 are marked on the sheet pile. A hole (A, B, C, D ...) of about 2 mm to 4 mm is made on the cutting line 3 of the sheet pile 1 at a pitch of 500 mm to 700 mm by a drill or the like. Cutting is performed along the cutting lines every other line A to B, C to D, E to F of the ruled line 3 shown in FIG. Next, the remaining portions B to C, D to E are cut, and the cutting of the sheet pile 1 is completed.

[0004]

However, the conventional cutting method described above has the following drawbacks. That is,
Compared with the method of cutting all at once as shown in FIG.
Even in the case of cutting every other B, C to D, ..., the bending value after cutting is large. That is, FIG. 6 is a diagram showing the degree of bending when the sheet is cut by the conventional method, and the average value of the bending is 21 mm when the length of the sheet pile is 17 m. In order to follow the cutting ruled line, a worker manually adjusts the work. Since every other cutting is performed, a profile shift (irregularity) occurs on the cutting line and the cutting surface. Further, the material cost, labor cost, etc. are further increased due to the correction of the bend, and the quality and the appearance are not so preferable because the bend is included. The present invention is to solve the above problems when cutting the conventional sheet pile,
It is an object of the present invention to provide a highly efficient cutting method that does not require bending correction.

[0005]

The present invention relates to a method for cutting a sheet pile with a self-propelled gas cutter, in which a roller is attached to the tip so as to sandwich the sheet pile with respect to the self-propelled gas cutter. A plurality of jigs were attached and further integrated with the gas cutting machine, a preheating gas instrument for preheating along the gas cutting line was attached, and a roller was attached to the tip while self-propelled on the sheet pile. A vertical cutting gas cutting method for a sheet pile, characterized in that the vertical cutting of the sheet pile is carried out by copying with a plurality of jigs and preheating with the gas cutting device for preheating at the start of gas cutting.

FIG. 1 is a diagram of a gas cutting apparatus according to the present invention. The gas cutting device 4 has a jig 5 having a roller 7 at the tip thereof having a function of copying the score lines 3 along the shape of the sheet pile main body, and preheating for preventing the occurrence of thermal strain at the time of gas cutting. The gas appliance 6 is attached to the conventional self-propelled gas cutting machine 2 shown in FIG.

As shown in FIG. 3, the jig 5 having the roller 7 at the tip has the roller 7 at the tip of the leg-like body, and the other end has a groove 8 and a bolt 9 for adjusting the angle. , And is attached to the gas cutting machine 2 via another protractor-shaped jig 10. FIG. 4 is a diagram in which four jigs 5 having rollers at the ends are attached to the gas cutting machine 2.
A plurality of jigs 5 having rollers at their tips can be attached so as to be bilaterally symmetrical. Reference numeral 11 is a cutting torch, but the two preheating torches 6 use oxygen of the same cylinder as the cutting torch 11. High pressure oxygen is used for the cutting torch, but the preheating torch is heated with oxygen at normal pressure. The oxygen pressure of these torches is adjusted by the valve 12 attached to the cutting device 4.

[0008]

The procedure of the cutting method of the present invention will be described with reference to FIG. First, a score line, which is a cutting line 3 to be cut, is inserted in the sheet pile 1. Next, the gas cutting device 4 of the present invention is placed on the sheet pile 1 to be cut, and the jig 5 having a roller 7 at the tip having a cutting copying function is adjusted and fixed in accordance with the size of the sheet pile. .. First, two preheating torches 6 are preheated from the tip of the sheet pile, and at the same time, the cutting torch 11 starts cutting the sheet pile. The power used at that time is that of a conventional self-propelled gas cutting machine.

FIG. 7 shows the accuracy of bending when the sheet pile is cut by the method of the present invention. As shown in FIG. 7, the bending after cutting was 4.7 mm when the length of the sheet pile was 17 m, which was a great improvement from the bending of 21 mm obtained by the conventional method. This bend is within the range of the allowable bend at the time of cutting, and the accuracy is such that the bend need not be corrected. Further, Table 1 shows the cutting work time by the conventional method and the method of the present invention at this time. As shown in Table 1, according to the method of the present invention, the cutting time per sheet pile was shortened by 1030 minutes / piece as compared with the conventional method, and highly efficient cutting work was realized.

[0010]

[Table 1]

[0011]

As described above, the present invention improves the working accuracy and the cutting accuracy by improving the cutting accuracy by automatically following the cutting line at the time of cutting and preventing the occurrence of bending due to thermal strain at the time of cutting. The effects such as improvement of quality and quality are extremely large.

[Brief description of drawings]

FIG. 1 is a view of a cutting device for carrying out a gas cutting method according to the present invention.

FIG. 2 is a diagram showing a conventional cutting method.

FIG. 3 is a jig in which a roller is attached to the tip of a leg-shaped body according to the present invention.

FIG. 4 is a view in which a jig having a roller attached to the tip of a leg-shaped body according to the present invention is attached to a gas cutting machine.

FIG. 5 is a diagram showing a conventional cutting method.

FIG. 6 is a diagram showing a degree of occurrence of bending when cut by a conventional method.

FIG. 7 is a diagram showing the degree of occurrence of bending when cut by the method of the present invention.

[Explanation of symbols]

 1 sheet pile 2 self-propelled gas cutting machine 3 scoring line 4 gas cutting device 5 jig with roller at the end 6 preheating torch 7 roller 8 groove for angle adjustment 9 bolt 10 protractor jig 11 cutting torch 12 valve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tetsuya Maehama 3-10-6 Kaibuchi, Kisarazu-shi, Chiba (72) Inventor Toshinori Sato 1 Kimitsu, Kimitsu-shi, Chiba Nippon Steel Corporation Kimitsu Works (72) ) Inventor Atsushi Nakanishi 1 Kimitsu, Kimitsu-shi, Chiba Nippon Steel Co., Ltd. Kimitsu Steel Co., Ltd. 8-3 (72) Inventor Fukushi Mamoru 1 Kimitsu, Kimitsu-shi, Chiba Nippon Steel Co., Ltd. Inside the Kimitsu Works

Claims (1)

[Claims] 1. A method for longitudinally cutting a sheet pile with a self-propelled gas cutter, wherein a plurality of jigs each having a roller at its tip so as to sandwich the sheet pile with respect to the self-propelled gas cutter. Attached, further integrated with the gas cutting machine, a preheating gas instrument for preheating along the gas cutting line is attached, and a plurality of jigs with rollers at the tip while self-propelled on the sheet pile. A method for vertically dividing a sheet pile, which is characterized in that the sheet pile is vertically cut while being preheated by the gas appliance for preheating at the same time as the start of gas cutting.