JP2500549Y2 - Pipe fitting - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention relates to a pipe joint, and more particularly to a mechanical pipe joint capable of confirming completion of attachment to a connecting pipe.

2. Description of the Related Art FIG. 6 shows a commercially available mechanical type pipe joint developed by the present applicant. The ends of the pipe members 30, 31 formed of steel pipes opposed to each other on the axis are connected by a pipe joint. At both ends of the metal joint body 21 made of a casting or the like, male threads are provided on the outer peripheral surfaces respectively, and tapered inner taper holes are formed on the inner peripheral surfaces of the both ends in which the inner diameter is gradually reduced inward from the end surfaces. . The inner peripheral diameter d of the innermost portion having the smallest diameter of each taper hole is inserted with the pipe members 30 and 31 having the outer peripheral diameter D to be connected.

Further, the tightening nuts 24 are connected to the male threads on both sides of the joint body 21 by the female threads on the inner circumference. A side wall-shaped flange 26 is provided at one end of the tightening nut 24.
A lock ring 27 having a taper portion 27a formed on the outer circumference is interposed between the flange 26 and the outer circumferences of the pipe members 30 and 31, and the taper portion 27a is fitted into a taper hole 26a provided in the flange 26. Although not shown, a threaded locking claw is formed on the inner peripheral surface of the lock ring 27. When you tighten the tightening nut 24,
The lock ring 27 advances together with the tightening nut 24, and firmly contacts the outer peripheral surfaces of the pipe members 30 and 31 to which the locking claws on the inner peripheral side of the lock ring 27 are connected.

Further, a ring-shaped rubber packing 28 and a washer 29 made of metal or the like are provided between the joint body 21 and the tightening nut 24. The packing 28 has an inner peripheral diameter that is fitted to the outer peripheral surfaces of the pipe members 30 and 31, and the outer peripheral portion has a tapered portion 28a that fits into a tapered hole formed in the joint body 21. The packing 28 is inserted into the tapered hole of the joint body 21 by fitting the taper portion 28a, and the tightening nut 24 is screwed into the joint body 21, so that the packing 28 is inserted through the lock ring 27 and the washer 29. The elastic member is pushed into the tapered hole while being elastically deformed, and is closely attached to the outer peripheral surfaces of the pipe members 30 and 31 by the wedge action, so that a required sealing property is secured.

When the pipe joint is attached to the pipe members 30 and 31, the pipe joint is prepared in a state where the above-mentioned components are temporarily set. Two pipe members 30, 31 connecting from both sides of the joint body 21
Insert each end of. Manually tighten the tightening nuts 24 on both sides in the tightening direction. After temporary tightening, a tool such as a pipe wrench is hooked on the outer peripheral corners of the tightening nuts 24 on both sides to perform final tightening. At this time, by the forward movement of the tightening nut 24 to the joint body 21 by tightening, the washer 29 and the packing 28 are pushed toward the tapered hole of the joint body 21 inside the tightening nut 24, and the packing 28 becomes the tapered hole. While being pushed in, it elastically deforms and comes into close contact with the outer peripheral surfaces of the tube members 30, 31. The packing 28 ensures the sealing performance between the pipe members 30 and 31. Further, the elastic force of the packing 28 increases the screwing force between the joint body 21 and the tightening nut 24, so that the tightening nut 24 can be prevented from loosening.

In the case of the mechanical pipe joint shown in FIG. 6, it is not necessary to perform additional processing such as thread cutting on the pipe members 30 and 31 to be connected at the site, and simply tighten the bag-shaped tightening nut 24 on the cut end. Can be installed. Further, there is an advantage that the packing 28 can absorb a mechanical load due to vibration and pressure fluctuation on the pipe members 30 and 31 to some extent.

However, in the conventional pipe joint shown in FIG. 6, the tightening of the tightening nut 24 on the joint body 21 is adjusted by the operator's manual adjustment, and it is difficult to determine the optimum tightening amount.
The determination of the optimum tightening amount of the tightening nut 24 depends only on the skill of the operator. For this reason, variations in the assembly work are likely to occur, and it is difficult to secure the required sealability. Further, even if the tightening nut 24 is only temporarily tightened by hand tightening, if leakage does not occur in the water flow test or in the early stage of use after construction, there is a risk of forgetting the main tightening with a dedicated tool. Moreover, there is no way for the operator to recognize that the user has forgotten to tighten the book. On the other hand, if the tightening is insufficient, the tightening nut 24 may loosen due to fluid vibration or water hammer phenomenon, the packing 28 may not be sufficiently press-fitted, and the adhesion may be insufficient, resulting in an unexpected situation of fluid leakage.

Therefore, an object of the present invention is to provide a pipe joint in which a tightening nut can be tightened with a uniform optimum tightening amount and the final tightening can be clearly confirmed.

Means for Solving the Problem A pipe joint (1) according to the present invention has a male body (3) formed on the outer periphery of both ends and a joint body having a step (4) formed adjacent to the male screw (3). (2) and a tightening nut (6) having a female screw (7) screwed to the male screw (3) of the joint body (2) and a side wall portion (8a) with a hole through which the pipe member (30) is inserted. , Fitting body (2) and pipe member (30)
And an elastic seal member (10) disposed between the joint body (2) and the step (4) of the joint body (2) and the tip (8c) of the tightening nut (6). ) Mounted on the outer periphery of the joint ring (4) and the tightening nut (6) when the tightening nut (6) is tightened. ) Abut the tip (8c).
The display ring (12) has an annular boundary (15) that is cut or plastically deformed when a predetermined amount of axial pressing force is applied. When the tightening nut (6) is tightened while generating a predetermined amount of axial pressing force, the indicator ring (12) is irreversibly cut or plastically deformed at the boundary (15), and the indicator ring (12) is ) The width of the display ring is reduced and the display ring (1
2) is a non-recoverable reduced width, and the step (4) of the joint body (2)
And the tip (8c) of the tightening nut (6).

In the embodiment of the present invention, the joint body (2) has a tapered hole (5) through which the pipe member (30) is inserted and the diameter of which is gradually reduced inward. The elastic seal member (10) has a tapered surface (10) that fits into the tapered hole (5) of the joint body (2).
b). An elastic seal member (10) and a washer (11) are mounted on the outer periphery of the pipe member (30) between the joint body (2) and the tightening nut (6). When the tightening nut (6) is tightened, the elastic seal member (1
0) is pressed against the tapered hole (5) of the joint body (2).

Action After temporarily tightening the pipe joint, if the tightening nut (6) is fully tightened using a special tool, etc., the step (4) of the joint body (2) and the tip of the tightening nut (6) (8c The display ring (12) sandwiched between () and) is irreversibly cut or plastically deformed at the boundary (15). Therefore, the operator can visually confirm that the tightening nut (6) is insufficiently tightened, and can prevent forgetting to fully tighten the tightening nut (6). At the same time, when the pipe joint is disassembled after installation, the indicator ring (12 By confirming the cutting or plastic deformation of), it is possible to clearly determine whether or not the work has been performed with an appropriate tightening amount.

Embodiment An embodiment of the pipe joint according to the present invention will be described below with reference to FIGS.

FIG. 1 to FIG. 5 show only one side of a bilaterally symmetrical pipe joint 1 formed in a tubular shape from a metal such as a casting or a synthetic resin. At the end of the joint body 2, a male screw 3 is formed from the end face to the outer peripheral face, and an annular step portion 4 adjacent to the male screw 3 and protruding from the outer peripheral face is formed. Further, tapered holes 5 are formed on both inner peripheral sides of both ends of the joint body 2 so as to gradually decrease in diameter. A pipe member 30 such as a steel pipe having an outer diameter D to be connected is inserted into a minimum hole diameter d in the inner portion of the tapered hole 5. Pipe fitting 1
The joint body 2 is not limited to the straight tube shape of this embodiment, but may be an elbow shape with both ends intersecting at an angle of 90 degrees.

A tightening nut 6 is screwed to the male screw 3 of the joint body 2. The outer periphery of the tightening nut 6 is formed in a polygonal shape to which a tool such as a pipe wrench is hooked. A female screw 7 is formed on the inner peripheral surface of the tightening nut 6 so as to be screwed to the male screw 3 of the joint body 2, and a flange (side wall) 8a is formed at one end of the female screw 7.
Is formed. Flange 8a has a tapered hole 8b that expands inward
The lock ring 9 is fitted into the tapered hole 8b. The lock ring 9 is interposed between the flange 8a and the pipe member 30, and the outer periphery serves as a tapered portion 9a and has a tapered hole 8b on the flange 8a side.
And a locking claw 9b that engages with and locks into the outer periphery of the pipe member 30 is formed on the inner peripheral surface in a screw shape. As the tightening nut 6 is tightened, the locking claw 9b on the inner peripheral side of the lock ring 9 is reduced in diameter and locked to the outer peripheral surface of the pipe member 30.

The tip 8c of the tightening nut 6 faces the front surface 4a of the step portion 4 of the joint body 2. Tip 8c of tightening nut 6 and joint body 2
Between the step portion 4 and the display ring shown in FIG. 3 and FIG.
12 are interposed. The indicator ring 12 is the male thread 3 of the joint body 1.
Has an inner diameter attached to the outer periphery of the. A large-diameter ring 13 and a small-diameter ring 14 are continuously formed on the display ring 12, and an annular boundary portion 15 is formed at a connecting portion between the large-diameter ring 13 and the small-diameter ring 14.
Is formed. When a predetermined axial pressing force is applied from both the large diameter ring 13 side and the small diameter ring 14 side, the indicator ring
12 is sheared at the boundary 15 so that the large-diameter ring 13 and the small-diameter ring 14 are separated from each other. The wall thickness of the boundary portion 15 is set so as to cut with a predetermined axial pressing force.

Further, the elastic seal member 10 formed by the ring-shaped rubber packing and the washer 11 made of metal are provided in the joint body 2
It is mounted on the outer circumference of the pipe member 30 between the and the tightening nut 6.
The packing 10 has an inner peripheral diameter through which the pipe member 30 can be inserted, and a taper surface 10b that fits into the taper hole of the joint body 2 is formed on the outer peripheral portion. The taper surface 10b of the packing 10 is fitted into the taper hole 5 of the joint body 2 and strongly pressed, and the packing 10 is accommodated while being elastically deformed by the wedge action. The elastic force at this time causes the outer peripheral surface of the tube member 30 to come into close contact with the outer peripheral surface of the pipe member 30 to ensure the required sealing performance. By tightening the tightening nut 6 via the washer 11, the packing 10 is pressed into the tapered hole 5 of the joint body 2.

As shown in FIG. 1, when the parts of the pipe joint 1 are assembled on the outer circumference of the ends of the pipe member 30, the indicator ring 12 is provided between the step 4 of the joint body 2 and the tip 8c of the tightening nut 6. The tightening nut 6 is tightened by hand tightening in a loosely fitted state. The lock ring 9 advances as the tightening nut 6 is tightened, and the packing 10 and the washer 11 are pressed against the joint body 2. The packing 10 is fitted into the tapered hole 5 of the joint body 2 while being elastically deformed. When the tightening nut 6 is temporarily tightened with a small rotational force, the display ring 12 comes into contact with the step portion 4 of the joint body 2 and the tip 8c of the tightening nut 6 to limit the temporary tightening. In this case, since the boundary portion 15 of the display ring 12 is in an uncut state or in a non-plastically deformed state, the operator can visually confirm the insufficient tightening of the tightening nut 6 and prevent forgetting to fully tighten the tightening nut 6.

After that, when the tightening nut 6 is further fully tightened using a dedicated tool or the like, the indicator ring 12 sandwiched between the step portion 4 of the joint body 2 and the tip 8c of the tightening nut 6 has a boundary portion 15 The large diameter ring 13 and the small diameter ring 14 are separated from each other by cutting with.
When the tightening nut 6 is sufficiently tightened, as shown in FIG. 2, the small-diameter ring 14 overlaps with the large-diameter ring 13 in such a manner that the small-diameter ring 14 sunk into the large-diameter ring 13 and the display ring 12 has a non-recoverable reduced width b Decrease to. After that, the tightening of the tightening nut 6 by the special tool becomes impossible. At this stage, inside the tightening nut 6, the packing 10 is strongly pushed into the tapered hole 5 of the joint body 2 by the lock ring 9, and the pipe member 30
The space between the joint body 2 and the joint body 2 is sealed, and the pair of pipe members 30 can be connected airtightly and liquidtightly with a required sealing property.

At this time, the width B of the display ring 12 including the large-diameter ring 13 and the small-diameter ring 14 is reduced to b, and the operator can visually confirm the completion of the final tightening of the tightening nut 6 and tighten each pipe joint. The nut 6 does not have a non-uniform tightening amount, and a certain sealing performance can be secured. Further, since the display ring 12 is cut, the tightening nut 6 is not subjected to the elastic repulsive force by the display ring 12 after tightening, and the tightening nut 6 can be prevented from loosening.

After tightening, the locking claw on the inner peripheral side of the lock ring 9
9b advances integrally with the tightening nut 6 and has a reduced diameter,
It firmly engages with the outer peripheral surface of 30 and imparts a pull-out preventing force to the tube member 30. Further, since the packing 10 closely contacts the outer peripheral surface of the pipe member 30 and the tapered surface 5 of the joint body 1 and presses the joint body 2 in the direction of expanding the diameter, the male screw 3 of the joint body 2 and the tightening nut 6 are The screw coupling force with the female screw 7 is strengthened, and the tightening nut 6 is prevented from loosening.

As described above, when the display ring 12 is cut into the large-diameter ring 13 and the small-diameter ring 14 and tightened to the width b of the large-diameter ring 13, it can be determined that the main tightening is completed. At this time, the small diameter ring
Since 14 moves inside the large diameter ring 13 and can not be seen,
At the stage where the surface of the small-diameter ring 14 colored in “red” or the like can be visually observed, if the final tightening is insufficient and the surface of the small-diameter ring 14 is not completely visible after cutting, it can be recognized that the final tightening is completed. Further, by disassembling the pipe joint after the construction and confirming the cutting or plastic deformation of the display ring 12, it can be clearly determined whether or not the construction is carried out with an appropriate tightening amount.

FIG. 4 (a) shows another embodiment of the present invention in which the display ring 16 is formed in an L-shaped section, and FIG. 4 (b) is formed in which the display ring 17 is formed in a Y-shaped section. The indicator rings 16 and 17 contact the step portion 4 of the joint body 2 and the tip 8c of the tightening nut 6, and both are cut or plastically deformed at the boundary portion 15 when an axial pressing force of a predetermined magnitude is applied. , Becomes a flat shape with a reduced width.

Effect of the Invention As described above, in the pipe joint of the present invention, the tightening nut can be tightened with a uniform optimum tightening amount, and the final tightening can be confirmed by the recoverable deformation of the indicator ring.

[Brief description of drawings]

FIG. 1 is an assembled sectional view showing an embodiment of a pipe joint according to the present invention before tightening a tightening nut, FIG. 2 is an assembled sectional view after tightening, FIG. 3 is a partial sectional view of a display ring, and FIG. (A) and (b) are perspective views showing two modified examples of the display ring, FIG. 5 is an exploded perspective view of a pipe joint according to the present invention, and FIG. 6 is an assembled sectional view of a conventional pipe joint. 1 ... Pipe fitting, 2 ... Fitting body, 3 ... Male thread, 4 ...
Steps, 5 ... Tapered holes, 5 ... Tightening nuts, 7 ... Female thread, 8a ... Flange (side wall), 8c ... Tip, 9 ...
Lock ring, 10 ... Packing (elastic seal member), 10
b …… Tapered surface, 11 …… Washer, 12 …… Display ring, 1
3 …… Large diameter ring, 14 …… Small diameter ring, 15 …… Boundary part, 3
0 ... Pipe member

Claims (2)

(57) [Scope of utility model registration request] 1. A joint body (2) having a male thread (3) formed on the outer periphery of both ends and a step (4) formed adjacent to the male thread (3), and a male thread of the joint body (2). A tightening nut (6) having a female screw (7) screw-connected to (3) and a side wall portion (8a) with a hole through which the pipe member (30) is inserted;
An elastic seal member (10) arranged between the joint body (2) and the pipe member (30), a step (4) of the joint body (2), and a tip (8c) of the tightening nut (6). And a display ring (12) which is interposed between the joint body (2) and mounted on the outer circumference of the joint body (2), and is used for tightening the tightening nut (6).
In the pipe joint (1) in which 2) contacts the step (4) of the joint body (2) and the tip (8c) of the tightening nut (6), the display ring (12) has an axial direction of a predetermined size. When the tightening nut (6) is tightened while generating a predetermined amount of axial pressing force, the indicator ring (12) has an annular boundary part (15) that cuts or plastically deforms when receiving a pressing force. ) Is irreversibly cut or plastically deformed at the boundary portion (15), and the width of the display ring (12) is reduced, and the display ring (12) has an irrecoverable reduced width and the step portion (2) of the joint body (2). 4) A pipe joint characterized in that it is sandwiched between the tip (8c) of the tightening nut (6). 2. The joint body (2) has a tapered hole (5), through which the pipe member (30) is inserted and the diameter of which is gradually reduced inward, at the inner periphery, and the elastic seal member (10) is 2) has a tapered surface (10b) that fits in the tapered hole (5), and has an elastic seal member (10) on the outer circumference of the pipe member (30) between the joint body (2) and the tightening nut (6). ) And washer (11) are attached and the tightening nut (6) is tightened, the washer (1
The pipe joint according to claim 1, wherein the elastic seal member (10) is pressed against the tapered hole (5) of the joint body (2) via the (1).