JPH0315897Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a connection mechanism for a thin-walled stainless steel pipe and a joint that can easily and reliably connect the thin-walled stainless steel pipe and the joint on-site.

[Conventional technology]

Traditionally, iron pipes, copper pipes, vinyl pipes, etc. have been used as materials for indoor piping that transfers fluids, such as water pipes.However, iron pipes and copper pipes are prone to corrosion, resulting in deterioration in fluid quality and fluid leakage. On the other hand, vinyl pipes have the disadvantages of low heat resistance and low strength against freezing, etc., so in recent years thin-walled stainless steel pipes, which have excellent corrosion resistance, heat resistance, cold resistance, and even mechanical strength, have been developed. Steel pipes began to be used. However, this thin-walled stainless steel pipe also had the following problems. In other words, thin-walled stainless steel pipes are hard and highly elongated materials, and because stainless steel pipes are expensive, it is difficult to thread the pipes to make them as thin as around 1 mm for economic efficiency. It is. For these reasons, connections with joints are made by soldering, welding, or pressing, but these connections are weak against tension and cannot be removed, and they are susceptible to corrosion at the joints. The disadvantage is that it is easy to cause problems, and the connection work requires skill. Therefore, the applicant of this invention first filed Utility Application No. 58-2005 (Utility Application No. 59-107390).
No.), it can be used on-site and is resistant to tension.
We proposed a connection mechanism between thin-walled stainless steel pipes and joints that is removable and less prone to corrosion at the joints.

[Problem that the invention attempts to solve]

However, this conventionally proposed connection mechanism still has one unresolved problem.
In other words, when tightening a nut to a joint, it is impossible to visually determine whether or not it has been completely tightened. There are two methods to check the gap between the end face of the nut and the flange of the joint facing the nut using a limit gauge, but these methods are time-consuming and impractical. be.

[Means for solving problems]

This idea was made in view of the above circumstances, and the means for achieving this idea is a thin stainless steel tube with a convex portion formed on the outer periphery of the end, an inner diameter into which the thin walled stainless steel tube is inserted, and a tube with an inner diameter for inserting the thin walled stainless steel tube. a nut having a fitting portion facing the fitting and the convex portion and fitting externally into the thin-walled stainless steel pipe, and a female thread portion screwing into the male thread of the fitting; In a connection mechanism between a thin-walled stainless steel pipe and a joint, which includes a packing provided between the joint and the thin-walled stainless steel pipe, the convex portion of the thin-walled stainless steel pipe is formed into a chevron-shaped protrusion having two inclined surfaces. , a first notch consisting of a tapered part that closely contacts the chevron-shaped protrusion and a seal fitting part is formed on the inner periphery of the end of the joint, and a flange having a flange end surface is provided on the outer periphery of the first notch, and the nut is provided with a flange having a flange end surface. , a second notch is formed at the inner end of the fitting portion to tightly contact one of the sloped surfaces of the chevron-shaped protrusion, and when the female thread of the nut and the male thread of the joint are screwed together, the joint is secured. A joint contact surface formed by the difference in inner diameter between the fitting part and the female threaded part is formed, and the end face of the nut comes into contact with the fitting surface, and when the female threaded part of the nut and the male thread of the joint are screwed together and fixed, The other inclined surface of the chevron-shaped protrusion formed on the thin-walled stainless steel pipe, the joint contacting surface of the nut, and the fitting fitting part of the joint are formed so as to be in close contact with each other, and the outer periphery of the joint is colored on the convex surface. This is where the disc spring applied is fitted onto the outside so that it is located between the end face of the nut and the end face of the flange.

[Effect]

When constructing a connection mechanism using the above means, it is performed as follows. First, a gasket is fitted into the gasket fitting part of the joint, and then the end of the thin stainless steel pipe is inserted into the inside of the externally fitted joint with the colored convex surface of the disc spring on its outer periphery facing toward the flange end surface. Then, the male thread formed on the outer periphery of the end of the joint and the female thread of the female thread of the nut are screwed together until the joint contact surface of the nut abuts the tip of the joint, and the chevron-shaped protrusion of the thin-walled stainless steel pipe is , the tapered part of the joint, the second notch of the nut, and the packing prevent it from coming off. Furthermore, the seal closely contacts the inclined surface of the chevron-shaped protrusion, the seal fitting portion, and the joint contact surface, thereby preventing leakage of fluid flowing within the thin-walled stainless steel pipe. Also, when the nut is screwed in until the joint contact surface contacts the tip of the joint, the disc spring is compressed between the nut end face and the collar end face, and the spring is compressed and tightened until the colored display on the convex surface is no longer visible. , to visually manage how to tighten the nut.

〔Example〕

Hereinafter, embodiments of this invention will be described based on the drawings.

The connection mechanism between a thin-walled stainless steel pipe and a joint of this invention is composed of a thin-walled stainless steel pipe 1, a joint 2, a nut 3, a packing 4, and a disc spring 5, as shown in FIGS. 1 to 4.

The thin-walled stainless steel pipe 1 has two inclined surfaces 6 in cross section formed by expanding the pipe diameter on the outer periphery of the end thereof.
It has a mountain-shaped protrusion 6 having ridges a and 6b. The joint 2 has a tapered portion 7 on the inner peripheral surface of its end.
A and a gasket fitting part 7b form a first notch 7, and a male thread 8 is formed on the outer peripheral surface of the end, and a collar 9 is provided that faces the end surface of the nut when the nut is tightened. The nut 3 includes a fitting portion 10 that fits externally into the thin-walled stainless steel pipe 1;
Due to the difference in the inner diameter between the fitting part 10 and the female thread part 11, the internal diameter is larger than that of the fitting part 10, and the internal circumferential surface has a thread groove into which the male thread 8 of the joint 2 is screwed. Joint contact surface 12 formed by
and a second notch 13 formed at the inner end of the joint contact surface 12. Further, the packing 4 is used by being fitted into the packing fitting part 7b of the joint 2, and when the connection between the thin-walled stainless steel pipe 1 and the fitting 2 is completed, the chevron-shaped protrusion 6 of the thin-walled stainless steel pipe 1 and the packing of the fitting 2 are inserted. Fitting part 7b,
The packing is made of an elastic material such as rubber and has a rectangular cross section and has adhesive surfaces that can be brought into close contact with the joint contact surfaces 12 of the nut 3. Further, when the nut 3 is screwed into the joint 4, the disc spring 5 is attached to the joint 2 so that it is located between the nut end surface 3a and the collar end surface 9a of the collar 9 of the joint 2 facing the nut end surface 3a.
The convex surface 5a is colored. The thin-walled stainless steel pipe 1, the joint 2, the nut 3, the packing 4, and the disc spring 5 configured as described above constitute a connection mechanism as follows.

First, one or two nuts 3 are fitted onto the thin stainless steel pipe 1, and then the pipe diameter is expanded at one or both ends of the steel pipe 1 to form a mountain-shaped protrusion 6. At this time, the inclined surface 6b of the chevron-shaped protrusion 6
It is most desirable to make the inclination angle of the nut 3 and the inclination angle of the second notch 13 of the nut 3 equal to each other. Although a tube expansion device as shown is used, it goes without saying that devices other than this tube expansion device may be used. The tube expansion device shown in FIGS. 5 and 6 has a tube expansion head 14 fixed to a base (not shown).
The main components include a shaft 15 movably inserted into the tube expansion head 14, a rubber receiver 16 fitted onto the shaft 15, a tube expansion rubber 17 and a rubber presser 18, and a locking part 19 fixed to the tip of the shaft 15. This is a requirement, and the pipe expansion operation is performed as follows.

First, as shown in FIG.
A male thread 20 formed on the outer periphery of the nut 4 and a female thread 11 of the nut 3 fitted onto the thin stainless steel pipe 1.
Screw and secure the female screws. At this time, the shaft 15, rubber receiver 16, tube expanding rubber 17, rubber presser 18, and locking part 19 are inserted from the end of the thin stainless steel tube 1 at the same time. Then, when the shaft 15 is pulled in the direction of arrow A using a device not shown, the rubber receiver 16 comes into contact with the tube expansion head 14, as shown in FIG. After that, when the shaft 15 is pulled in the direction of arrow A, the locking part 19 pushes the rubber presser 18 in the direction of arrow A, so that the expanding rubber tube 17 compressed by the rubber receiver 16 and rubber presser 18 reduces its width. Since it is reduced, it expands in the circumferential direction by the reduced volume. The second notch 13 of the nut 3 and the tube expansion head 1 are attached to the outer periphery of the expanded tube expansion rubber 17.
Since there is a mountain-shaped space 22 formed by the notch 21 formed on the inner circumferential surface of the tip of the tube 4, the thin-walled stainless steel tube 1 has a mountain-like space 22 at its end as the tube expansion rubber 17 expands in the circumferential direction. When the chevron-shaped protrusion 6 is formed by expanding into the shaped space 22, the angle of inclination of the inclined surface 6b of the chevron-shaped protrusion 6 and the second notch 13 of the nut 3 are
Since the angles of inclination of the pipes are exactly the same, there is an advantage that the axes are aligned and the degree of adhesion is improved.In addition, the nut 3 that is screwed into the joint 2 can be used as part of a pipe expansion jig to form a chevron shape on the stainless steel pipe 1. Since the protrusion 5 is formed into an expanded tube, the workability for forming the chevron-shaped protrusion 5 is greatly improved.

After completing the expansion of the thin-walled stainless steel pipe 1 as described above, the seal fitting part 7b of the joint 2
After fitting the packing 4 into the joint 2, the end of the thin stainless steel pipe 1 is inserted into the joint 2. Further, a disc spring 5 is fitted around the outer periphery of the joint 2 with its colored convex surface 5a facing the flange end surface 9a side. Then, when the male thread 8 formed on the outer periphery of the end of the joint 2 and the female thread of the female thread part 11 of the nut 3 are screwed in until the joint contact surface 12 of the nut 3 abuts the tip of the joint 2, the thin-walled stainless steel pipe 1 The chevron-shaped protrusion 6 is compressed and fixed by the tapered portion 7a of the joint 2, the second notch 13 of the nut 3, and the packing 4. Furthermore,
The gasket 4 is in close contact with the inclined surface 6a of the chevron-shaped protrusion 6, the gasket fitting portion 7b, and the joint contact surface 12,
To prevent leakage of fluid flowing inside the thin-walled stainless steel pipe 1. Also, when the nut 3 is screwed in until the joint contact surface 12 contacts the tip of the joint 2, the disc spring 5
are compressed and brought into close contact between the nut end surface 3a and the collar end surface 9a, and the colored display on the convex surface 5a becomes invisible and the nut is completely fastened.

[Effect of idea]

As is clear from the above explanation, according to this invention, the corresponding notches formed on the joint and the nut are brought into close contact with the two inclined surfaces of the chevron-shaped protrusion formed at the end of the thin-walled stainless steel pipe. Since it is tightened in the direction of , it is possible to increase the pull-out strength of the thin-walled stainless steel pipe. In addition, when the nut is tightened, the tip of the joint comes into contact with the joint contact surface of the nut, increasing the frictional resistance between the female thread and the male thread, resulting in a strong tightening force. . Furthermore, by tightening the two opposing slopes of the chevron-shaped protrusion with both the nut and the joint, the parts of the joint and nut that contact the slopes slightly press down on the slope of the chevron-shaped protrusion. The elastic repulsive force of this chevron-shaped protrusion is transmitted to both the nut and the joint, and furthermore,
The elastic repulsive force of the gasket provided between the chevron-shaped protrusion and the joint and the disc spring provided between the joint and the nut is added to this, and the frictional force at the threaded portion of the female thread of the nut and the male thread of the joint is further improved. Therefore, loosening of the nut caused by bending, vibration, twisting, etc. of the thin stainless steel pipe can be prevented. Furthermore, by installing a disc spring, the degree of tightening of the nut can be easily checked visually, so insufficient tightening or forgetting to tighten can be determined at a glance, making inspection easy and at the same time preventing these problems. It can be useful. In addition, since the seal is stored in the seal fitting part, even if the thin stainless steel pipe expands and contracts due to temperature changes, the compression and expansion of the volume is extremely small, so the life of the seal can be extended. .

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view showing an embodiment of this invention, Fig. 2 is a -sectional view of Fig. 1, Figs. 3 and 4 are enlarged longitudinal cross-sectional views of main parts, and Fig. 5 is a formation of a protrusion. An explanatory diagram showing the process from a vertical cross-section of the tube expansion rubber during normal operation,
FIG. 6 is an explanatory view from a longitudinal section when the expanded tube rubber is compressed. 1...Thin-walled stainless steel pipe, 2...Fitting, 3...
... Nut, 3a ... Nut end surface, 4 ... Packing, 5 ... Belleville spring, 6 ... Chevron-shaped protrusion (convex part),
6a, 6b... Slanted surface, 7... First notch, 7a
...Tapered part, 7b...Puttle fitting part, 8
... Male thread, 9 ... Tsuba, 9a ... Tsuba end surface, 10 ...
...Fitting portion, 11...Female thread portion, 12...Joint contact surface, 13...Second notch.

Claims (1)

[Scope of Claim for Utility Model Registration] A thin-walled stainless steel pipe with a convex portion formed on the outer periphery of its end, a joint having an inner diameter into which the thin-walled stainless steel pipe is inserted, and a male thread formed on the end, and a joint with the convex portion formed on the end. A nut having a fitting part facing the boundary and externally fitting into the thin-walled stainless steel pipe and having a female thread part screwing into the male thread of the joint, and a packing provided between the joint and the thin-walled stainless steel pipe. In the connection mechanism of a thin-walled stainless steel pipe and a joint, the convex part of the thin-walled stainless steel pipe is formed into a chevron-shaped projection having two inclined surfaces, and the joint has a convex part on the inner periphery of the end thereof. A first notch is formed with a taper part and a packing fitting part that come into close contact with each other, and a flange having a flange end surface is provided on the outer periphery of the first notch, and the nut has the chevron-shaped protrusion at the inner end of the fitting part. A second notch is formed that closely fits one of the inclined surfaces, and the inner diameter difference between the fitting part and the female thread is abutted by the end face of the joint when the female thread of the nut and the male thread of the joint are screwed together and fixed. The other inclined surface of the chevron-shaped protrusion formed on the thin-walled stainless steel pipe when the female thread of the nut and the male thread of the joint are screwed together and fixed to each other. , formed so as to be in close contact with the joint contact surface of the nut and the seal fitting part of the joint, and furthermore, a disc spring having a colored convex surface on the outer periphery of the joint is located between the nut end face and the collar end face. A connection mechanism between a thin-walled stainless steel pipe and a fitting characterized by external fitting.