JPH04101714A - Single-cut cutting device for steel pipe - Google Patents

Abstract

PURPOSE:To follow speed-up of a continuous steel pipe cutting device by displacing a cutting edge from an axis position of a steel pipe regardless of a single-cut by means of a cutting blade, in a steel pipe cutting mechanism of a continuous steel pipe manufacturing system. CONSTITUTION:A die set repeats a reciprocating motion where it is accelerated to a speed coincident with a delivery speed of a steel pipe 1 while being supported by both lower slide rails 9L, 9R and an upper slide crank rail 7, cut the steel pipe 1 at the time of the same speed, is decelerated to stop to retreat, and is accelerated from the original position toward the next position. A single-cut cutting mechanism is composed of clamps 3a, 3b for opening/closing in the horizontal direction the die set which moves at the same speed as the steel pipe 1 delivered at a constant speed and a cutting blade 2 which moves in the vertical direction. A cutting edge 5 at a top end of the cutting blade 2 starts cutting at a position displaced from the center of the steel pipe 1 retained by the clamps 3a, 3b, and positioned within 20 % of a diameter from the outside end face thereof in a plan view.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a steel pipe cutting mechanism disposed in the final process of a continuous steel pipe manufacturing system.

(B) Prior art Conventionally, steel pipes have been manufactured by continuously supplying steel plate strips, gradually forming them into a cylindrical diameter using forming rolls, and joining the joints to form the cylinder using a continuous welding device. The system is known.

The continuously manufactured steel pipe is then accelerated to a speed that matches the speed of the steel pipe in order to cut it into predetermined lengths,
A technique related to a die set that grips an elongated steel pipe with a clamp when the speed reaches the same speed as the steel pipe and simultaneously cuts it with a cutting blade is known.

For example, there is a technique described in US Pat. No. 4,337,680.

(C) Problems to be Solved by the Invention However, in the prior art, as shown in the drawing of the prior art in FIG. The part of
When it bites into the center of the steel pipe, a dimple 1 will be created in that part.
1, a dimple-like recess is formed, so in order to eliminate this dimple 11, a notching blade N is provided in the notch portion of the cutting blade 5 to first make a cut K of several millimeters.

Therefore, the speed is accelerated to the speed of the steel pipe being fed out at high speed, and when the speed reaches the same speed, a double cutting is performed by first making a cut K with the notching blade N, and then cutting with the cutting blade 13, that is, a double cut. It constituted a mechanism called

However, the double cutting method described above complicates the structure of the die center, and the movement stroke of the cutting blade 13 becomes longer as it waits for the notching plaid to finish cutting, resulting in a larger die set as a whole. be.

Furthermore, in order to achieve even higher speed cutting in the case of a double set, it is necessary to increase the operating speed of the notching blade and also the operating speed of the cutting blade, making it impossible to keep up with the increased speed of continuous steel pipe cutting equipment. There was a problem.

The present invention solves these problems.

(d) Means for Solving the Problems The problems to be solved by the present invention are as described above. Next, the means for solving the problems will be explained.

In the steel pipe cutting mechanism, the continuously supplied steel strip is formed into a tubular shape, the joints are welded in the next process, and the steel pipes are continuously cut into predetermined dimensions in the next process. The clamp 3a opens and closes the die set moving at the same speed in the horizontal direction.
3b, and a cutting blade 2 that moves up and down, the cutting blade 2
The cutting blade 5 at the tip first makes a cut in the steel pipe held by the clamps 3a and 3b at a position offset from the center of the steel pipe within a range of 20% of the diameter from the outer end surface of the steel pipe in plan view, and then It is designed to cut the entire diameter.

(E) Embodiment The problems to be solved by the present invention and the means for solving them are as described above.Next, the structure of the embodiment shown in the attached drawings will be explained.

Figure 1 is a front view of the die set, Figure 2 is a side view,
FIG. 3 is a plan view, FIG. 4 is a front sectional view showing the cutting section of the steel pipe single-cut cutting mechanism of the present invention, and FIG.
FIG. 6 is a front view showing an embodiment of the cutting blade 2 of the present invention, and FIG.
The figure is a front view showing a conventional double cut cutting mechanism.

The outline of the die set will be explained with reference to FIGS. 1, 2, and 3.

The die set is supported by both the lower sliding rails 9L and 9R and the upper sliding crank rail 7, and is accelerated to a speed that matches the unwinding speed of the steel pipe 1, and when the same speed is reached, the steel pipe is unrolled. The machine repeats a reciprocating motion in which it cuts a piece, then decelerates, stops, retreats, and accelerates from the initial position to the next cutting position.

The reciprocating movement of the entire die set is achieved by the fact that the tip of the reciprocating rank is jointed to the joint 15, and the joint 15 is fixed to the die center by a fixing part 16. Ru. Although the reciprocating rack is not shown, it is reciprocated by being switched by a forward/reverse motor.

Further, the lower sliding rails 9L and 9R are fixed in a horizontal state, but the upper sliding crank rail 7 is moved up and down by a crank drive mechanism (not shown), and due to the vertical movement, it slides with the upper rail 17. The cutting blade fixing portion 8 of the cutting blade 2 moves up and down via the cylinders 6L and 6R.

In the crank motion of the sliding crank rail 7, when the speed exactly matches the speed of the steel pipe 1, one crank rotation is performed to move the cutting blade 2 up and down.

The sliding tubes 6L and 6R slide inside the lower receiver tubes 14L-14R and are supported vertically.

The clamps 3a and 3b are expanded and contracted by a clamp cylinder 10 provided on the side thereof, and the clamps 3a and 3b, which are normally opened by a biasing spring, are clamped only when cutting by the cutting blade 2 via a cam mechanism. Cylinder control valve 18
Under this control, the clamp cylinder 10 is extended, the clamps 3a and 3b are made to protrude from both sides, and the steel pipe 1, which is moving at the same speed, is gripped at the center.

Conventionally, the vertical movement force of the cutting blade fixing part 8 was extracted to rotate or move the notching blade N laterally, but in this double cut between the notching blade and the cutting blade 2, , it is not possible to cope with the increase in the speed of cutting equipment.

Although the present invention is a single cut using the cutting blade 2, it is possible to make a single cut without creating dimples 11.

Next, referring to FIG. 4, the configuration of the main parts of the present invention will be explained.

As shown in FIG. 7, the reason why the double cut is adopted in the conventional die set mechanism is that the cutting blade 5 is located at the center of the cutting blade 13, so that the biting position of the cutting blade 5 is at the center of the steel pipe 1. Because of this, the central part of the steel pipe 1 is easily bent because there is no support part below, and the central part of the steel pipe 1 is bent downward, resulting in the formation of dimples 11.

In the present invention, such a problem occurs because the cutting blade 5 is located at the center position, so even if the cutting blade 5 makes a cut, the steel pipe 1 is at a position where it is less likely to bend. 20% of the diameter from the outer end face of steel pipe 1, not the center
The cutting blade 5 is configured to be driven into the eccentric position up to.

In Fig. 4, if the distance from the axial center position of the steel pipe 10 to the position of the cutting blade 5 is the distance a from the cutting blade 5 to the outer end surface of the steel pipe 1, then the distance a is approximately up to 20% of the diameter. It is located at Therefore, the distance is 30% or more of the diameter.

In this way, at a position close to the side, the hollow state of the lower part changes, and the wall pressure part of the steel pipe is located below.

Even if the cutting blade 5 bites directly downward, there is no room for the wall pressure part of the steel pipe to flex, as shown in the center part of Fig. 7. Thereby, even if the cutting blade 5 bites into the eccentric position, the dimple 11 will not occur.

After first biting into the cutting blade 5, the entire diameter of the steel pipe 1 is cut by the entire cutting blade 2.

5 and 6 show examples of the cutting blade 2 in the case of the steel pipe single-cut cutting mechanism of the present invention,
There is a difference in the shape of the rear part between the slanted type and the straight type.

2a is a bolt hole for fixing the cutting blade 2 to the cutting blade fixing part 8.

(F) Effects of the Invention Since the present invention is constructed as described above, it has the following effects.

First, although it is a single cut by the cutting blade 2,
By deviating the cutting blade 5 from the axial position of the steel pipe 1, it was possible to eliminate the occurrence of dimples.

Second, by using a single-cut non-dimple, the conventional notching plaid and cutting blade structure required a drive mechanism for both blades, making the die set complicated. By configuring as above, there is no need for a notching plaid, resulting in a simple structure.

Thirdly, in the past, the downward stroke of the cutting blade was increased in order to buy time for cutting the notching plaid, but in the case of the present invention, there is no need to buy time for cutting the notching plaid. Therefore, the stroke of the cutting blade 2 could be made smaller.

Fourthly, in the case of a double cut, a skilled technique was required to adjust the cutting timing between the notching plaid and the cutting blade 2, but by making a single cut,
This eliminates the need for expert skill in adjusting these double-edged blades.

Fifth, compared to double cut, it has a simpler structure,
Because it was lighter in weight, it became possible to cut at high speeds, making it possible to speed up the entire continuous steel pipe manufacturing system.

Sixth, maintenance became easier, and since there was only one blade, it was possible to shorten the time required for replacement.

[Brief explanation of drawings]

Figure 1 is a front view of the die set, Figure 2 is a side view,
FIG. 3 is a plan view, FIG. 4 is a front sectional view showing the cutting section of the steel pipe single-cut cutting mechanism of the present invention, and FIG.
FIG. 6 is a front view showing an embodiment of the cutting blade 2 of the present invention, and FIG.
The figure is a front view showing a conventional double cut cutting mechanism. 1... Steel pipe 2... Cutting blades 3a, 3b... Clamp 5... Cutting blades 6L, 6R... Sliding tube

Claims (1)

[Claims] In the steel pipe cutting mechanism, the continuously supplied steel strip is formed into a tubular shape, the joints are welded in the next process, and the steel pipes are continuously cut into predetermined dimensions in the next process. The clamp 3a opens and closes the die set moving at the same speed in the horizontal direction.
3b, and a cutting blade 2 that moves up and down, the cutting blade 2
The cutting blade 5 at the tip first makes a cut in the steel pipe held by the clamps 3a and 3b at a position offset from the center of the steel pipe within a range of 20% of the diameter from the outer end surface of the steel pipe in plan view, and then A single-cut cutting mechanism for steel pipe, characterized in that it is configured to cut the entire diameter of a steel pipe.