JPH0246465B2 - NEJITSUKIKOKANNONEJIBUHOGOZAI - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a method for coating and protecting the surface of a threaded part carved on the end of a threaded connection type steel pipe to prevent it from being damaged during the transportation process of the steel pipe. The present invention relates to a material for protecting threaded parts of steel pipes.

[Conventional technology]

Welding is generally a well-known joint method for large and medium-diameter steel pipes, and various types of protective materials are available to protect the pipe end bevel of welded steel pipes from damage during transportation. Are known.

On the other hand, in cases where welding cannot be performed due to the prohibition of open flames, such as oil pipes used at oil drilling sites, tapered threads are provided at the ends of the steel pipes in advance, and each steel pipe is threaded at the site. Connection methods are also known. By the way, as a protective material to protect the threaded surface of this type of screw-connected steel pipe from damage during transportation, a separate metal cap with a tapered thread that matches the tapered threaded surface of the steel pipe is engraved in advance is used. A widely used method is to manufacture a metal cap and screw it onto the end of the tube.

[Problem that the invention seeks to solve]

In this way, conventional threaded steel pipe thread protection materials involve carving a tapered thread into the metal cap that matches the tapered thread at the end of the pipe.
An outer cap with a tapered thread on the inner surface to match the tapered thread on the outer surface of the tube end, and an inner cap with a tapered thread on the outer surface to match the tapered thread on the inner surface of the tube end. There is a problem in that two types of caps have to be prepared, and the cost of manufacturing the caps is extremely high. Of course, these caps must be prepared in various sizes to match the different diameters of the pipes, and the tapered threads carved into the caps must be made with precision to match the tapered threads of the steel pipes. It must be sufficient in terms of
In addition to the high processing costs, the cap is removed from the end of the tube after transportation and is discarded as a consumable item after use, so the large amount of money required to manufacture the cap is completely wasted, and it is extremely wasteful. The problem was that it was uneconomical.

On the other hand, in order to solve these problems with metal caps, a belt-shaped body made of rubber or synthetic resin is made into a ring shape, and this belt-shaped ring is attached to the threaded surface of the steel pipe, and the surface of this belt-shaped ring is There is a method of crimping with a metal fastening band, for example, a fastening band that compresses the diameter of the band by driving wedge-shaped stops at both ends, as is usually used for this type of pipe end protection material. Conceivable.

However, since the threaded surface of the tube end is tapered, if the shape of the tightening band is also tapered to match the tapered threaded surface of the tube end, this tightening band can be compressed with a wedge-shaped stopper. However, it becomes difficult to uniformly compress the entire band into a tapered shape, resulting in the problem that the band ring cannot be properly crimped onto the tapered threaded surface.

Therefore, instead of making the shape of the tightening band tapered, the cross section of the band-shaped ring is made into a tapered shape that matches the tapered thread surface of the tube end, and the tightening band is parallel to the circumferential surface of the tube, and is wedge-shaped. The entire length of the tightening band must compress the band ring evenly when the fastener is driven.

However, when a band-shaped ring is made of a soft material such as rubber or synthetic resin and has a tapered cross-section that matches the tapered threaded surface of the pipe end, the thickness of the band-shaped ring is thicker at one end and thicker at the other end. As the ring becomes thinner, distortion occurs due to the difference in wall thickness after cooling during molding, making it difficult to form a proper ring.

[Means for solving problems]

The present invention solves the problems of the thread protection material for threaded steel pipes as described above, and uses a combination of a band-shaped ring made of a soft material such as rubber or synthetic resin and a metal tightening band. It is much cheaper and more economical than metal caps, and by making the band-shaped ring a special structure,
It is an object of the present invention to provide a threaded part protection material that can be molded into a distortion-free shape that properly fits the tapered threaded surface of the other end.

The present invention provides a rubber or synthetic resin that is applied to a tapered threaded surface carved on the outer circumferential surface of the end of a steel pipe or the inner circumferential surface of the end of the steel pipe as a specific means for obtaining the above-mentioned threaded part protection material. It consists of a belt-shaped ring with a tapered cross section made of a soft material such as, and a metal tightening band for crimping the belt-shaped ring to the tapered thread surface. It is characterized by being bent into a tapered cross-sectional shape over the entire body.

[Effect]

In the thread protection material according to the present invention, when forming a band-shaped ring made of a soft material into a tapered cross-section, the entire cross-section of the band-shaped body forming this ring is made by bending a membrane having a uniform thickness into a bellows shape. Since the overall shape of the strip is tapered, the cross-section of the strip is tapered, but since the thickness of the membrane forming the strip is uniform, the overall shape of the strip is tapered. It is possible to form a proper band-shaped ring without any distortion.

In addition, since the thickness of the membrane that forms the strip is uniform in all parts, when the ring made of this strip is crimped against the tapered thread surface with the outer tightening band, the tightening band has a uniform thickness. Compressive force can be applied uniformly to the membrane in each part, and the protective effect on the threaded surface can be made uniform over the entire length.

〔Example〕

Next, an embodiment of the thread protection material according to the present invention will be described with reference to the drawings. FIG. FIG. 3 is a perspective view showing a component configuration. This outer protective material 3A is formed by a band-shaped ring 4A made of a soft material such as rubber or synthetic resin that is adhered to the outer circumferential surface of the outer circumferential tapered screw 2A, and a band-shaped ring 4A that is fitted onto the outer circumferential surface of this band-shaped ring 4A. ring 4
and a metal tightening band 5A for crimping the tapered screw 2A onto the surface of the tapered screw 2A.

The belt-shaped ring 4A is made of polyethylene and crosslinked polyethylene and is extrusion-molded as a long belt-shaped body 6 as shown in FIG.
It is formed into a ring shape by cutting the pipe to a predetermined length that matches the diameter of the steel pipe 1 and then gluing both ends 7 together. When forming the band-shaped body 6, the cross-sectional shape of the band-shaped body 6 has a tapered shape with a large wall thickness at one end and a small wall thickness at the other end, but the film 8 has a uniform wall thickness from one end to the other end. are bent at appropriate intervals and shaped so that the thicker end and the thinner end are continuous.

In this case, since the strip 6 is attached to the tapered thread 2A on the outer circumferential surface of the tube end as described above, the inner circumferential surface of each membrane 8 corresponds to the tapered thread 2A as shown in FIG. A tapered surface 6a is formed, and the outer circumferential surface is a horizontal surface 6b similar to the circumferential surface of the tube. Additionally, flanges 9 are provided protruding from both ends of the horizontal surface 6b on the outer periphery to prevent movement of the tightening band 5A. Note that the tapered surface 6 of the inner circumference
It is desirable to provide a convex-concave surface for close contact with the tapered screw 2A.

Furthermore, a groove 10 consisting of a gap opened toward the inner circumferential surface is provided at the outer end of the band-shaped body 6, that is, the thicker end side, and a separately formed steel pipe is inserted into the groove 10. A flange 11 made of a soft material for protecting the tube end surface 1a of the tube 1 is fitted later.

The band 6 is cut to a predetermined length and both ends 7 are glued together to form a cylindrical band ring 4A having an inner diameter that fits into the end of the steel pipe 1. The band ring 4A is fitted into the end of the steel pipe 1, and at the same time the flange 11 is installed in the groove 10 on the inner peripheral surface of the tip.

After the band ring 4A is fitted into the tube end, a metal tightening band 5A is fitted around the outer periphery of the band ring 4A. This tightening band 5A has inclined folded pieces 12a, 12b on both side edges of one end, and the folded pieces 12a, 12b at the center of the other end.
Each of these folded pieces 12a, 12b, 12 has an oppositely inclined folded piece 12c that fits between the
The band diameter is compressed by driving the wedge-shaped stopper 13 into the tube c, and the inner band-shaped ring 4A is crimped onto the tapered thread 2A on the outer peripheral surface of the tube end.

Next, FIG. 4 shows a component configuration of an inner side protection member 3B for protecting a tapered screw 2B carved on the inner circumferential surface of the end of the steel pipe 1. This inner side protective material 3B is inserted into a band-shaped ring 4B made of the same material as described above, which is attached to the inner circumferential surface of the inner circumferential surface tapered screw 2B, and the inner circumferential surface of this band-shaped ring 4B. and a metal tightening band 5B for pressure-bonding the tapered screw 2B to the surface of the tapered screw 2B.

The band-shaped ring 4B in this case is also obtained by extrusion molding a band-shaped body 6 having the same shape as the band-shaped ring 4A, but in the case of the band-shaped ring 4B, the taper of the membrane 8 is opposite to that of the band-shaped ring 4A. It is formed into a cylindrical shape such that the surface 6a is the outer peripheral surface and the horizontal surface 6b is the inner peripheral surface. As a result, the groove 10 is located on the outer periphery of the thick part of the tip as shown in FIG. A protective flange 11 of the tube end 1b is installed in the groove 10.

However, the tightening band 5B used in the case of this inner protection material 3B has folded pieces 12d and 12e facing each other at both ends, and these folded pieces 12
By driving the wedge-shaped stoppers 13 into the holes d and 12e, the diameter of the band is expanded, and the outer band-shaped ring 4B is crimped onto the tapered screw 2B on the inner peripheral surface of the tube end.

〔effect〕

As described above, the threaded part protection material according to the present invention has a tapered threaded surface engraved on the outer circumferential surface or inner circumferential surface of the tube end with a belt-shaped ring made of a soft material such as rubber or synthetic resin. Since it is composed of a belt-shaped ring and a metal tightening band that is crimped onto the tapered screw surface, the material itself is low cost and the processing cost is low, making it significantly easier to manufacture than conventional metal protective caps with threads cut into them. Cost reduction can be expected.

In addition, since the band-shaped ring that covers the tapered thread surface connects the band-shaped bodies formed into a tapered cross-section in a ring shape, the band-shaped bodies with the same cross-sectional shape are used for the outer circumferential tapered thread part and the inner circumferential tapered thread part. It can be used for both purposes and can be expected to reduce costs in this respect as well.

Furthermore, even if the band-shaped ring is formed into a tapered cross-section, the film, which has a uniform thickness throughout, is bent into a bellows shape to form a thicker part and a thinner part. It is possible to form a ring without distortion, and to obtain a high-quality threaded part protection material that can uniformly transmit the pressure force from the tightening band to the tapered threaded surface at any part.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing the component configuration when the threaded part protection material according to the present invention is applied as an outer protection material for an outer peripheral surface tapered screw; Fig. 2 is a perspective view of a band-shaped body constituting a band-shaped ring; Figure 3 is a cross-sectional view of the outside protection material attached to the tube end, and Figure 4 shows the component configuration when the thread protection material according to the present invention is applied to the inside protection material for the internal tapered thread. The perspective view and FIG. 5 are cross-sectional views of the inner side protection material attached to the tube end. 1: Steel pipe, 2A, 2B: Tapered thread surface, 3
A: Protective material for the outside, 3B: Protective material for the inside, 4A,
4B: Band-shaped ring, 5A, 5B: Tightening band,
6: Band-shaped body, 8: Membrane, 9: Tightening band movement prevention flange, 10: Concave groove, 11: Tube end face protection flange, 13: Wedge-shaped stop.

Claims (1)

[Scope of Claims] 1. A belt-shaped ring with a tapered cross section made of a soft material such as rubber or synthetic resin and adhered to a tapered threaded surface carved on the outer peripheral surface or inner peripheral surface of the end of a steel pipe. , and a metal tightening band for crimping the belt-like ring onto the tapered threaded surface, and the belt-like ring has a tapered cross-section over the whole by bending a membrane of uniform thickness into a bellows shape. A protective material for the threaded part of a threaded steel pipe, characterized by being formed into a shape. 2. The belt-shaped ring is for covering the tapered threaded surface on the outer peripheral surface of the pipe end of the steel pipe from the outside, and a metal tightening band is fitted onto the outer peripheral surface of the belt-shaped ring and is driven into both ends of the band. 2. The threaded portion protection material for a threaded steel pipe according to claim 1, wherein the diameter is compressed by a wedge-shaped stopper, and the belt-like ring is crimped onto the tapered threaded surface. 3. The belt-shaped ring is for covering the tapered threaded surface on the inner circumferential surface of the end of the steel pipe from the inside, and a metal tightening band is fitted on the inner circumferential surface of the band-shaped ring, and a metal tightening band is fitted on the inner circumferential surface of the band-shaped ring, and The threaded portion protection material for a threaded steel pipe according to claim 1, wherein the diameter is expanded by a wedge-shaped stopper that is driven in, and the belt-like ring is crimped onto a tapered threaded surface.