JP2002276874A - Joint for flexible tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately compress packing for gas leak detection even if a connection thread is tightly fastened in connection of a flexible tube used for gas tube. SOLUTION: In a joint for flexible tube, length L1 of an internal thread part 15 provided on a cylindrical main body 11 from an inner surface opening end and length L2 of an external thread part 26 provided on a pushing ring 25 screwed therein from an insertion side end are shorter than a travel length L0 of the pushing ring 25 screwed in the cylindrical main body 11. Length D of a shaft part not provided with the external thread is roughly equal to length L1 of the internal thread part 15 and a diameter R of the shaft part is roughly equal to an inner diameter of the internal thread 15. When the external thread 26 is screwed in the internal thread 15 to achieve a designated compression amount of the packing 30, the internal thread part 15 gets into the part without the external thread 26 to prevent generation of fastening force of the threads more than that.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joint for a flexible tube used for a gas pipe.

[0002]

2. Description of the Related Art Conventionally, as a tube for a gas tube, a flexible tube in which the outer periphery of a thin-walled stainless steel corrugated tube is covered with a resin-made tubular covering is known.

When such flexible tubes are connected, it is natural that the corrugated tubes are connected without leakage. However, if the tube-shaped coverings are connected without leaking, the following problems occur.

[0004] That is, when constructing a house provided with gas piping, nailing is often performed after piping the flexible tube. At this time, the tip of the nail that is accidentally driven reaches the flexible tube. If you do,
A nail breaks through the corrugated tube, causing a gas leak at that point.

[0005] On the other hand, the elastic resin covering is closely attached to the periphery of the penetrating nail, and no gas leaks from this portion to the outside. For this reason, the corrugated tube 2
The gas leaked out of the joint flows into the inside of the joint through the gap between the corrugated pipe 2 and the covering 3.

[0006] Therefore, if the tubular coverings 3 are connected without leakage, the leakage cannot be recognized, and a dangerous situation is expected. Therefore, this type of flexible pipe joint connects the corrugated pipes 2 without leakage, but connects the gas leaked between the corrugated pipe 2 and the tubular coating 3 so that the gas can leak to the outside. Gas leaks can be detected immediately after nailing work, and early during the construction of a house, that is, during the construction phase when the house is not yet completed. To be able to find and respond appropriately.

As a joint for a flexible tube satisfying such a demand, a joint as shown in FIGS. 5 to 7 has been proposed, for example, in Japanese Patent Application No. 10-52584.
Hereinafter, a joint for connecting the flexible tube 1 will be described.

The flexible tube joint includes a cylindrical main body 11 made of metal such as brass, a retainer 35 that engages with the outer periphery of the corrugated tube 2, and a threaded fitting with the cylindrical main body 11 to form the annular body. The retainer 35 is held in the cylindrical main body 11 and a push ring 25 for pushing the corrugate tube 2 to the back of the cylindrical main body 11 as described later is provided, and the push ring 25 is screwed into the cylindrical main body 11 to The packing 30 between the open end surface of the cylindrical main body 11 and the opposing end surface of the pressing wheel 25 is compressed at a constant pressure, and the inside gas is allowed to pass therethrough, but water is prevented from passing from the outside to the inside. .

In FIG. 1, reference numeral 12 denotes a male thread portion provided at one end of the cylindrical main body 11 so as to be connectable to a connected object such as a gas pipe. A hexagonal portion 13 is used for screwing the male thread portion 12. 14 is an end surface on the other end side.

On the inner circumference at the other end of the cylindrical body 11, in order from the opening side, a female thread portion 15, an inner peripheral surface 16 having an inner diameter larger than the valley of the female thread portion 15, A tapered surface 17 having a smaller diameter than the peripheral surface 16 and having a diameter gradually reduced toward the inner side of the cylindrical main body 11 is formed.

Reference numeral 18 denotes an end surface of the female thread portion 15 on the opening end side, which is formed radially at a position slightly deeper than the end surface 14. At the back end of the cylindrical main body 11, an annular sealing material accommodation groove 19, an annular contact surface 20 located on the inner peripheral side with respect to the accommodation groove 19, and an inner peripheral side with respect to the contact surface 20. An annular projection 21 that is located and protrudes toward the opening side of the tubular main body 11 is formed. The accommodation groove 19 accommodates an O-ring 22 as a sealing material.

The pressing wheel 25 is formed in a cylindrical shape from a metal such as brass, and has a male screw portion 26 which can be screwed into the female screw portion 15 of the cylindrical main body 11 at one end thereof.
A hexagonal portion 27 for screwing operation is formed on the outer circumference on the other end side of the pressing wheel 25. The hexagonal portion 27 is formed to have a larger diameter than the external thread portion 26, and thus has an end face 28 facing the end face 14 of the tubular main body 11.

The end face 28 has an annular packing accommodation groove 2.
9 is formed, and an annular packing 30 is accommodated in the accommodation groove 29. The packing 30 is formed of, for example, a nonwoven fabric or a porous resin, which does not allow water to pass therethrough but allows gas to pass therethrough.

A radial end face 31 is formed in a portion between the accommodation groove 29 and the external thread portion 26. This end face 31
FIG. 5 shows a state in which the pressing wheel 25 is screwed into the cylindrical main body 11.
As shown in the figure, the cylindrical body 11 is configured to be in contact with the end face 18 of the female thread portion 15. An annular groove 32 is formed on the outer periphery of the pressing wheel 25 further on the distal end side than the male thread portion 26. A packing 33 is provided on the inner periphery of the pressing wheel 25.

A retainer 35 is attached to the tip of the pressing wheel 25. The retainer 35 has an inner peripheral protrusion 36 that fits into the annular groove 32 of the press wheel 25, and an inner peripheral protrusion 37 that engages with the valley of the corrugated tube 2. The retainer 35 can be elastically expanded in diameter by forming slits at a plurality of positions along the circumferential direction in the portion of the inner peripheral protrusion 37.

In such a configuration, when forming a joint, as shown in FIG.
9, the O-ring 22 is accommodated, a retainer 35 is attached to the tip of the pressing wheel 25, and packings 30 and 33 are attached.

Then, the pressing wheel 25 in that state is connected to the cylindrical main body 1.
Screw into 1. At this time, a spacer 39 is sandwiched between the end face 14 of the cylindrical main body 11 and the end face 28 of the pressing wheel 25. The spacer 39 is formed in a C-shape with resin or the like, and is sandwiched between the end face 14 of the tubular main body 11 and the end face 28 of the press ring 25 to temporarily screw the press ring 25 into the cylindrical main body 11. State. In this provisionally screwed state, the portion where the inner peripheral projection 37 is formed is attached to the inner peripheral surface 16 of the cylindrical main body 11.
Is located corresponding to.

As shown in the drawing, the joint 3 in which the pressing ring 25 is temporarily screwed into the cylindrical main body 11 is in a state where the covering 3 in a range corresponding to several peaks at the tip of the corrugated pipe 2 is removed. The flexible tube 1 is inserted into the joint from the opening of the pressing wheel 25. Then, the corrugated tube 2
Of the retainer 35 in a state where the diameter expansion is not hindered by being positioned corresponding to the inner peripheral surface 16, and the portion of the retainer 35 where the inner peripheral protrusion 37 is formed While elastically pushing and expanding the inner peripheral projection 3
Pass through part 7. When the ridge at the tip of the corrugated pipe 2 passes, the retainer 35 elastically reduces its diameter and returns to the original state, and the inner peripheral projection 37 engages with the valley of the corrugated pipe 2. FIG. 6 shows the state at this time.

Next, the spacer 39 is removed, and a tool such as a wrench is engaged with the hexagonal portion 13 of the cylindrical main body 11 and the hexagonal portion 27 of the pressing wheel 25, and the pressing wheel 25 is screwed into the cylindrical main body 11. Then, the retainer 35 is pushed by the pressing wheel 25 to enter the inner peripheral side of the tapered surface 17, and the corrugated tube 2 is pushed by the inner peripheral projection 37 of the retainer 35 so that the retainer 35 comes out of the annular projection 21 of the tubular main body 11. Is

Then, when the pressing wheel 25 is further screwed in, as shown in FIG. 5, the crest at the tip of the corrugated tube 2 is moved between the inner peripheral projection 37 of the retainer 35 and the contact surface 20 of the cylindrical main body 11. Crushed.

As a result, the joining is completed. At this time, the corrugated tube 2 and the tubular main body 11 are joined in a metal sealed state, so that required sealing performance can be secured. At this time, the retainer 35
The tip of the O-ring 22 compresses the O-ring 22 in the housing groove 19, and the compressed O-ring 22 also presses the crushed portion of the corrugate tube 2, so that multiple seals can be secured. In this state, as described above, the retainer 3
Since 5 has entered the inner peripheral side of the tapered surface 17 of the cylindrical main body 11, the expansion of the retainer 35 is reliably prevented,
Therefore, the corrugated tube 2, that is, the flexible tube 1 is reliably prevented from coming out of the joint.

5, the end face 14 of the tubular body 11 presses and compresses the packing 30, as shown in FIG. 7, thereby causing the packing 30 to exhibit required sealing performance. At this time, the end surface 31 of the cylindrical body 11 is positioned with respect to the packing 30 by the end surface 31 of the cylindrical member 11 hitting the end surface 18 of the female thread portion 15 of the cylindrical body 11 by screwing the press ring 25 into the cylindrical body 11. You.

As a result, the packing 30 is appropriately compressed so as to have a thickness of 70 to 80% between the end face 14 and the accommodation groove 29, and the packing 30 does not allow water to pass but gas does as described above. Sealing performance can be exhibited.

As described above, the packing 30 is compressed, and the cover 3 of the corrugated pipe 1 is inserted into the inner periphery of the packing 33, thereby preventing water or the like from entering the joint.

[0025]

In such a conventional apparatus, the adjustment of the screwing force when the pressing ring 25 is screwed into the tubular main body 11 to crush the tip of the corrugated tube 2 is left to the worker at the site. Have been. At this time, even if it is sufficient to screw the press wheel 25 with a specified torque, the screw is often screwed in with an excessive force in an attempt to ensure a reliable seal by crushing.

However, in this case, as shown in FIG. 7, after the end face 31 of the press ring 25 hits the end face 18 of the cylindrical main body 11, further screwing is performed, and a strong force is applied. Is deformed, and as a result, the packing 30 is excessively compressed by the end face 14 of the tubular main body 11.

Then, although it is appropriate to compress the packing 30 to have a thickness of 70 to 80% as described above, the packing 30 is further compressed, and the required seal is required. There is a possibility that the performance, particularly the performance of passing gas, may be affected. Then, there is a problem that occurrence of the above-mentioned gas leak cannot be found.

Accordingly, an object of the present invention is to solve such a problem and to appropriately compress a gas leak detection packing.

[0029]

In order to achieve this object, the present invention provides a tubular body into which at least the tip of a corrugated pipe is inserted, an annular retainer engaging with the outer periphery of the corrugated pipe, In a flexible tube joint provided with a pressing ring screwed into the cylindrical body and a packing for sealing between the cylindrical main body and the corrugated pipe, the length of the screw portion of the screw is provided from the open end of the inner surface of the cylindrical main body. The length of the threaded portion of the male screw provided from the insertion side end of the pressing wheel that is screwed into the shaft is shorter than the total screwing movement length of the pressing wheel with respect to the cylindrical main body, and the shaft portion without the male screw is provided. Is approximately equal to the length of the threaded portion of the female thread, and the outer diameter of the coaxial portion is made substantially equal to the inner diameter of the female thread, a screw is screwed into the female thread, and the packing reaches a predetermined compression amount. Threaded portion of the serial internal thread in which the tightening force by more screw enters the portion having no male screw is prevented from occurrence.

With such a configuration, when the push ring is screwed into the cylindrical main body and the push ring is tightened as in the conventional case,
When the tightening force reaches a certain level, the female screw will enter the part without the male screw, so no matter how much you rotate the press ring, it will not be possible to tighten it anymore. The pressing ring is not screwed with excessive force, and it is possible to reliably prevent the packing from being compressed more than necessary due to excessive screwing.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 to 4 where the same members as those shown in FIGS. Will be described.

Here, on the inner periphery of the cylindrical main body 11, a female screw 15 and an inner peripheral surface 16 are provided in this order from the opening side.
Further, the pressing wheel 25 is the same in that it has a male screw 26 which can be screwed into the female screw 15 of the cylindrical main body 11 and has an end face 28 facing the end face 14 of the cylindrical main body 11.

In the above, the length of the screw 15 of the screw 15 provided from the open end face 14 of the inner surface of the cylindrical main body 11;
The length L2 of the threaded portion of the male screw 26 provided from the insertion end of the pressing ring is shorter than the total screwing movement length L0 of the pressing ring 25 with respect to the inner surface of the tubular main body 11, as shown in an enlarged manner in FIG.

The length D of the shaft portion 25a on which the external thread 26 of the pressing ring 25 is not provided is substantially equal to the length L1 of the screw portion of the screw 15 to be provided on the cylindrical main body 11, and the outside of that portion. When the diameter R is made substantially equal to the inner diameter of the female screw 15, a screw 26 is screwed into the female screw 15, and when the packing 30 reaches a predetermined compression amount, the screw portion of the female screw 15 becomes a shaft portion without the male screw 26. No further tightening force is generated by entering the portion 25a by the screw.

Therefore, according to this flexible tube joint, the corrugated tube 2 from which the covering 3 has been removed is inserted into the tubular main body 11 of the flexible tube joint shown in FIG. 3, and the pressing ring 25 is tightened. After the connection is made as shown in FIG.
Even if the push ring 25 is rotated in the screwing direction to apply a tightening force, the female screw 15 of the tubular main body 11 is
The push ring 25 passes through the external thread and enters the shaft 25a.

Accordingly, no further screw advancing force is applied to the cylindrical main body 11, and no further compressive force acts on the packing 30. Therefore, the function of the gas-permeable but water-impermeable packing is not impaired.

Further, the portion 25 where no external thread is provided is provided.
When the internal thread 15 enters the a, the pressing force against the packing is in an appropriate state, and the thread of the external thread 26 of the press ring 25 and the thread of the internal thread 15 abut against each other in the axial direction, so that the shaft Since the directional movement is restricted, the pressing force is kept constant.

In the above embodiment, the corrugated tube 2
Has been described with a push-fitting 25 through the retainer 35, but as shown in FIG. 4, a retainer 53 that engages with the inserted outer surface of the corrugated pipe 2, and the retainer 53 is inserted into the cylindrical main body 11. A one-touch type flexible tube joint, comprising: an annular rubber seal member 42 for sealing between a retaining ring 47 to be held in the outer periphery of the corrugated tube 2 and an inner surface of the cylindrical body 11; This can be similarly performed.

In this case, the retaining ring 47 corresponding to the pressing ring 25 in the above embodiment is screwed in advance and fixed to the cylindrical main body 11, but even if the female screw 15 is erroneously tightened at the construction site, the female thread 15 is fixed. Since the male screw 26 and the male screw 26 are not already screw-fitted, they are not further tightened, and the function of the packing is not impaired.

The other portion of the joint for a flexible tube will be described. In FIG. 4, reference numeral 41 denotes an annular sealing material accommodating portion. Before inserting the corrugated tube 2, as shown in FIG. Rubber sealing material 42
Are accommodated in a loose press-fit state. Seal material 42
The refractory part 43 located on the inner side of the tubular main body 11 and the general rubber part 44 located on the opening side of the tubular main body 11 with respect to the refractory part 43 are integrally formed in the axial direction. It is configured such that the corrugated tube 2 can be pushed inside.

In the figure, reference numeral 45 denotes a back end face of the sealing material accommodating portion 41, and the back end face 45 is formed in the radial direction to the inner peripheral side of the sealing material 42. This back end face 4
An annular protruding portion 46 protruding toward a position on the inner peripheral side of the sealing material accommodating portion 41 is formed continuously with the inner peripheral end of the inner peripheral portion 5. As shown in FIG. 4, when the corrugated pipe 2 is inserted into the inner peripheral portion of the sealing material 42, the annular projection 46 is configured to be inserted into the corrugated pipe 2 without a large gap. .

A hole 49 through which the flexible tube 1 is inserted is formed in the pressing wheel 47 in a penetrating state, and a packing 33 is provided in the hole 49 so that gas leaking into the joint leaks from the outside. It is kept out.

A tapered surface 50 whose diameter increases toward the distal end of the pressing wheel 47 is formed on the inner periphery of the distal end of the pressing wheel 47 in the hole 49. A housing groove 29 is formed in the end surface 28 of the pressing wheel 47, and a packing 30 is housed in the housing groove 29.

As shown in the figure, when the pressing ring 47 is screwed into the cylindrical main body 11, it is surrounded by the tapered surface 50 of the inner circumference of the pressing ring 47, the inner peripheral surface 16 of the cylindrical main body 11, and the end face of the sealing material 42. A space 51 is formed. In this space 51, an annular retainer 52 is arranged. The retainer 52 is formed of a metal material such as brass, and has a radially inward protrusion 53 formed at one end thereof, that is, at the back of the cylindrical main body 11. The projection 53 can be engaged with a valley of the corrugated tube 2. Retainer 5
A tapered surface 54 is formed on the outer periphery of 2 so as to be able to contact the inner peripheral tapered surface 50 of the press wheel 47.

Further, the retainer 52 has a plurality of circumferential cuts in the axial direction from the one end side having the protrusion 53 toward the other end. It is configured so that the diameter can be expanded. Retainer 5
An annular groove 55 having a rectangular cross section is formed on the outer circumference on one end side of the protrusion 2.
A ring spring 56 for urging the member to the illustrated reduced diameter state is fitted therein. A washer 57 is interposed between the seal member 42 and the retainer 52.

When the corrugated tube 2 is inserted, the protrusion 53 of the retainer 52 is automatically expanded at the peak of the corrugated tube 2, so that the corrugated tube 2 can be inserted all the way into the cylindrical main body 11. When the pulling force acts on the ridge, the protrusion 53 of the retainer 52 is caught by the valley, and the tapered surface 54 comes into contact with the inner peripheral tapered surface 50 of the pressing ring 47 to reduce the diameter in the radial direction.

[0047]

As described above, according to the present invention, there is provided a joint for connecting a flexible tube, wherein gas leaking from the corrugated pipe and entering the joint through the gap between the sheath and the corrugated pipe is removed. In a joint fitted with a packing for escape to the outside, the compression of the packing inserted between the distal end surface of the cylindrical main body and the base end of the push ring or the retaining ring screwed into the cylindrical main body is performed by double screw fitting. By shortening the length of the screw part to be joined, if the screw is screwed in more than the length of the screw part, the screw fitting will be disengaged and the tightening force of both screws will not be applied any more, so when connecting the corrugated pipe, In this way, excessive compression of the packing caused by the screw being screwed with excessive force can be avoided.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view of a joint for a flexible tube according to an embodiment of the present invention.

FIG. 2 is an enlarged view showing a main part in FIG. 1;

FIG. 3 is a partially cutaway front view showing a state before a flexible tube is joined to the joint of FIG. 1;

FIG. 4 is a partially cutaway front view of a one-touch joint for a flexible tube according to another configuration example of the embodiment of the present invention.

FIG. 5 is a partially cutaway front view of a conventional flexible tube joint.

FIG. 6 is a partially cutaway front view of another conventional joint, showing a state before a flexible tube is joined.

FIG. 7 is an enlarged view of a main part in FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flexible tube 2 Corrugated tube 3 Coating body 11 Cylindrical main body 15 Female thread part 25 Retaining ring 26 Male thread part 30 Packing 35 Retainer 47 Press ring 52 Retainer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hisao Onishi 4-1-2, Hirano-cho, Chuo-ku, Osaka-shi, Osaka Inside Osaka Gas Co., Ltd. (72) Inventor Atsunori Komura 4-chome, Hirano-cho, Chuo-ku, Osaka-shi, Osaka No. 1-2 Inside Osaka Gas Co., Ltd. 2-10-16 Minamikagaya Shinwa Sangyo Co., Ltd. (72) Inventor Kazuki Karagi 2-10-16 Minamikagaya Suminoe-ku, Osaka-shi, Osaka F term in Shinwa Sangyo Co., Ltd. 3H017 CA07 CA11

Claims (1)

[Claims] 1. A tubular body into which at least a tip of a corrugated tube is inserted, an annular retainer engaged with an outer periphery of the corrugated tube, a pressing wheel screwed into the tubular body, a tubular body and a corrugated tube. A flexible tube joint provided with a packing for sealing between the length of the screw portion of the screw provided from the open end of the inner surface of the cylindrical body and the insertion side end of the pressing wheel screwed into the joint. The length of the threaded portion of the male screw is shorter than the total screwing movement length of the pressing ring with respect to the cylindrical main body, and the length of the shaft portion where the male screw is not provided is substantially equal to the length of the threaded portion of the female screw. Equal, the outer diameter of the coaxial portion is made substantially equal to the inner diameter of the female screw, a screw is screwed into the female screw, and when the packing reaches a predetermined compression amount, the screw portion of the female screw enters the portion without the male screw. so A joint for flexible tubing in which no further tightening force is generated by screws.