JPS61197117A - Cutting method of pipe - Google Patents

Abstract

PURPOSE:To cut a pipe in high efficiency with no material loss, by cutting the tapered central part which is formed in the pipe fed in a predetermined length by pressing a drawing roller tapered so that the nearer is a position of its peripheral surface approaching the both end parts in the axial direction from the central part of the peripheral surface the smaller an external diameter of the roller decreases. CONSTITUTION:A pipe 5, being clamped by a chuck 1, is rotated. While drawing rollers 2a, 2b symmetrically provide tapers 20a, 20a, 20b, 20b so that the nearer approaches a position of the peripheral surface of the roller to its both end parts from the central part in the axial direction of the peripheral surface the smaller an external diameter of the roller decreases, and a tilt angle theta1 of said taper is equalized to the tilt surface of a tapered thread formed by a chaser in manufacture of a pipe nipple. When the pipe 5 is cut, a cutter 3, being lowered and pressing the central part between tapers 51, 51 formed in the pipe 5 while it is rotated, cuts the central part. A cut piece of the pipe, being fed out in the direction of an arrow head H in the drawing, applies tapered thread cutting to the both end tapers 51, 51 by the chaser.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel pipe cutting method, and more particularly to a pipe cutting method suitably employed in a metal pipe cutting process when manufacturing a pipe nipple for a pipe joint.

Conventionally, when manufacturing pipe nipples for pipe fittings, metal pipes are cut using a circular saw cutting method or a rotary cutting method, and both ends of the nipple rough material are attached to the resulting pipe cut pieces using a chaser with a tapered screw. However, when cutting metal pipes using the circular saw cutting method, it is inefficient because it takes time to cut the pipe, and a large amount of chips is generated because the saw blade has a depth of 2 to 3 mm. However, there are problems such as wastage of materials. On the other hand, when cutting a metal pipe using the rotary cutting method, as shown in FIG. When taper threading is performed on both ends of the wire with a chaser, there are problems such as shortening the life of the chaser.

In addition, in both the circular saw cutting method and the rotary cutting method, the diameter of the nipple rough material obtained by cutting is uniform, so if taper thread cutting is performed on both ends of the nipple rough material, the diameter of the nipple rough material obtained by cutting is uniform. As shown in FIG. 8(b), there is a problem in that the wall thickness of the tapered threaded portion 102 becomes smaller, resulting in a decrease in strength.

The present invention has been made in view of such problems, and its purpose is to be able to cut pipes with high efficiency without material loss, and to cut the resulting pipe pieces so that both ends of the nipple rough material) can be cut. It is an object of the present invention to provide a new and extremely useful pipe cutting method that can prolong the life of the chaser and improve the strength of the taper threaded part because the diameter of the pipe is reduced and the pipe is tapered.

That is, the pipe cutting method of the present invention achieves the above object by 1ffl.
! In order to achieve this, the pipe that has been passed through the chucks and fed a predetermined length is gripped by the chuck, the chuck is rotated together with the pipe, and then the pipe that has been fed the predetermined length is
A concave taper is formed in the pipe along the taper of the squeezing roller while pressing a squeezing roller whose outer circumferential surface is tapered so that the outer diameter of the roller becomes smaller as it approaches both ends in the axial direction from the center of the outer circumferential surface. , Next, after releasing the pipe from the chuck and feeding the pipe a predetermined length,
With the center of the taper of the pipe supported by a pair of left and right rotatable support rollers placed below, a disk-shaped cutter is pressed against the center of the concave taper and cut while rotating. This will be explained in detail below based on the drawings showing one embodiment.

1 to 3 are schematic front views sequentially showing the state in which the pipe is cut after forming a taper in the pipe by the cutting method of the present invention; FIG. 4 is a schematic side sectional view showing the state in which the pipe is tapered; FIG. 5 is a schematic side view showing the pipe being cut, where 1 is a chuck, 2a is a
and 2b are squeeze rollers, 3 is a cutter, 4a and 4b are support rollers, and 5 is a metal pipe.

The chuck 1 grips a pipe 5 sent by a pipe feeding device (not shown) and stopped at a predetermined position from the outer peripheral side, and is rotated by a motor or the like (not shown) while gripping the pipe 5. .

The squeezing rollers 2a and 2b are symmetrically tapered with tapers 20a, 20a, 20b, and 20b such that the outer diameter of the roller becomes smaller as it approaches both axial ends from the center in the axial direction of the outer peripheral surface of the roller. , 20a, 20b, 2
The inclination angle θ1 of 0b is the same or almost the same as that of a tapered thread formed by a chaser during pipe nipple manufacture, which will be described later. Also, a squeeze roller 2a.

Each of the pistons 2b is configured to be able to be pressed against and separated from the pipe 5 by a rod 6a of a piston 6 connected behind the piston 6 under hydraulic control or the like.

The pair of left and right support rollers 2a and 2b are arranged at positions separated from the squeezing rollers 2a and 2b by a predetermined distance in the feeding direction of the pipe 5. As shown in FIG. 5, these support rollers 2a and 2b are rotatably arranged side by side at an appropriate interval and support the pipe 5 fed by a pipe feeding device (not shown). is configured to do so. Incidentally, the surface on which the pipe 5 is supported by the support rollers 2a and 2b excludes the tapers 51 and 51, since the pipe 5 is formed with tapers 51 and 51 as shown in FIGS. 1 and 3. This is the lower outer peripheral surface.

Further, a disk-shaped cutter 3 is provided above the support rollers 2a, 2b so as to be able to rise, and when cutting the pipe 5, the cutter 3 descends to cause the pipe 5 to collapse as shown in FIG. The pipe 5 is rotated while pressing the center part of the formed taper 51.51, and the taper 5
1,51 will be cut at the center. Note that the cutter 3 is not located directly above the pipe 5, and as shown in FIG. 5, the center of gravity O of the cutter 3 is slightly eccentric toward the right support roller 4b.

The pipe cutting method of the present invention uses the above-mentioned device,
Do it as follows.

That is, a pipe feeding device (not shown)
・Stop the pipe 5 that has been fed through the gap and a predetermined length (Fig. 1), and grip the outer peripheral surface of the pipe 5 with a charm. Then, pipe 5 Charact...
Then, the squeezing rollers 2a, 2b arranged above and below are moved forward toward the pipe 5 side with the piston 8, with the pipe 5 sandwiched between them, and the tapers 20a, 20a, 20b, 20b of the squeezing rollers 2a, 2b are The outer peripheral surface of the pipe 5 (
In this way, the pipe 5 and the upper and lower squeezing rollers 2a, 2b are moved in the directions of arrows B and C as shown in FIG. 4 due to frictional force. As it rotates, the tapers 20a, 20a, 20b, 2
The outer circumferential surface of the roller marked with 0b presses against the outer circumferential surface of the pipe 5, and the pipe 5 is deformed to the diameter of the taper 2.
A concave taper is formed along 0a, 20a, 20b, and 2Qb.

Next, when this taper formation is completed, the rotation of the characto is stopped, the tapered pipe 5 is released from the characto, and the pipe 5 is moved by the pipe feeding device to the center of the taper 51.51. Part is cutter 3
Send it out so that it is located directly below. And taper 51
．． When the center part of the pipe 51 is located directly below the cutter 3, the pipe 5 is stopped and its lower outer circumferential surface excluding the tapers 51, 51 (lower outer circumferential surface of the part A) is connected to the pair of left and right support rollers 4a,
4b rotatably supported.

Next, the cutter is lowered while rotating the rotatably supported pipe 5 (portion A) in the direction of the arrow as shown in FIG.
51 and rotate it.

Then, the pipe 5 and the support rollers 4a, 4b rotate in the directions of arrows E, F, and G due to the pressing force of the cutter 3, and as shown in FIG. The cutting is done by biting into the hole.

In this way, the taper is formed and the nipple rough material is fed out in the direction of arrow H,
Such operations are repeated sequentially to form tapers 51 and 51 at both ends.
Nipple rough material on which 51 is formed is mass-produced. and,
Thereafter, the tapered portions 51 and 51 at both ends are tapered with a chaser to form a vibrator nipple 7 of a pipe joint as shown in FIG.

In order to further increase the cutting efficiency of the pipe 5, it is desirable to set the blade angle θ2 of the cutter 3 to approximately 30 to 50 degrees, and to extend the life of the blade, as shown in FIG. It is desirable that the tip be polished in two stages so that the angle of the tip is about 50 degrees and the continuation part is about 30 degrees.

Furthermore, considering that the required length L of the pipe nipple 7 varies, it is desirable that the cutter 3 be able to move in the same direction or in the opposite direction to the pipe feeding direction.

Further, the squeezing rollers do not necessarily need to be disposed at the top and bottom as in the above embodiments; for example, the squeezing rollers may be disposed on one side and the support rollers 4a and 4b as in the above embodiments may be disposed on the other side. You can leave it there.

As described above, according to the vibrator cutting method of the present invention, the pipe is tapered into a concave shape using a squeezing roller, and the tapered central portion is cut while being pressed and rotated with a carter. Unlike the saw cutting method, no chips are produced, and unlike the rotary cutting method, no bulges are produced.

Moreover, since both ends of the resulting pipe cut piece (nipple rough material) are tapered due to diameter reduction deformation,
It is extremely easy to perform taper thread cutting with a chaser, which greatly extends the life of the chaser, reduces the number of man-hours for replacing chasers, wRM, etc., improves machine operation rate, and reduces tool costs. This makes it possible to reduce the width. On top of that.

In this way, if both ends of the pipe cut piece (nipple rough material) are tapered by diameter reduction deformation, even if taper thread cutting is performed with a chaser, the threaded end 7 as shown in Figure 6.
Since the wall thickness of the pipe does not become thinner and remains almost constant, the resulting pipe puller has great strength. Furthermore, if you perform taper formation and cutting in a series of steps like Hoko,
It has many remarkable effects, such as being extremely easy to automate and increasing production efficiency.

[Brief explanation of the drawing]

1 to 5 show an embodiment of the method of the present invention,
Figures 1 to 3 are schematic front views sequentially showing the state where the pipe is tapered and then cut, Figure 4 is a side sectional view showing the state where the pipe is tapered, and Figure 5 is the stage where the pipe is cut. FIG. 6 is a cross-sectional view of a pipe nipple obtained by cutting and tapering both ends of a cut pipe piece using the method of the present invention, and FIG. 7 is a cross-sectional view showing an example of a cutter blade. Fig. 8 (a) is a cross-sectional view showing the cut end of a pipe cut by the conventional rotary cutting method, and Fig. 8 (b) is a cross-sectional view showing the cut end of the pipe cut by the conventional pipe cutting method. It is a sectional view of the pipe nipple obtained by taper thread cutting. 1... Chucks 2a, 2b... Squeezing roller 3... Cutters 4a, 4b... Support roller 5... Pipes 20a, 20b... Taper of squeezing roller 51.5
1...Pipe taper patent applicant: Agent of Nippon Steel Pipe Fittings Co., Ltd.
Patent Attorney Takashi Suzue - Figure 2 Figure 1 IJ! 1 Fall 2 Ma Jl+ell Figure 4 Figure 5 Figure 6 Figure 7 Figure 8

Claims (1)

[Claims] A pipe that has been passed through the chucks and fed in for a predetermined length is gripped by the chuck, and the chuck is rotated together with the pipe, and then the outer diameter of the roller is adjusted from the center of the outer peripheral surface toward both ends in the axial direction. A concave taper is formed on the pipe along the taper of the squeezing roller while pressing a squeezing roller whose outer circumferential surface is tapered so as to reduce the diameter of the roller, and then the pipe is released from the chuck and the pipe is stretched to a predetermined length. After feeding the pipe, a disc-shaped cutter is pressed against the center of the concave taper and rotated while the center of the taper of the pipe is supported by a pair of left and right rotatable support rollers arranged below. While letting
A pipe cutting method characterized by cutting.