JP3429186B2 - Pipe fittings - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe joint for connecting pipes by tightening a cap nut, and more specifically, for confirming tightening of the cap nut and preventing loosening after tightening, and further co-rotating the pipe during tightening. The present invention relates to a pipe joint that prevents the above.

[0002]

2. Description of the Related Art In the above-described cap nut tightening type pipe joint, the cap nut of the ordinary pipe joint is temporarily tightened to the joint body with a weak force such as by hand tightening to temporarily pipe the entire pipe, and then the cap nut of the pipe joint is further tightened. Perform a full tightening with a tightening tool such as a pipe wrench. At this time, if the cap nut is tightened halfway only by temporary tightening by hand and the piping work is completed by forgetting the main tightening with a wrench etc., no leak will be detected in the leak test after piping and Fluid may leak when the actual piping is used. Therefore, it is very important for the contractor to confirm whether or not the pipe joint at the connecting portion has been completely tightened and piped. Also, when tightening the cap nut, if the pipe rotates together with the tightening of the cap nut, the cap nut of the other end side connection part of the pipe may also rotate, which causes the cap nut of the other end connection part to rotate. There is a problem of loosening and adversely affecting the sealability. Therefore, it is important not to cause co-rotation of the pipe. Further, when connecting a stainless steel pipe, it is important to prevent the skimmer corrosion peculiar to the stainless steel pipe together with the airtightness.

Conventionally, as shown in FIGS. 7 and 8 disclosed in Japanese Utility Model Laid-Open No. 63-145089, a plate washer having only one surface colored is mounted between the flange of the joint body and the end of the cap nut. Then, when the nut is screwed into the joint body and the connection with the pipe is completed, the dish washer is clamped in an upright state between the body and the nut as shown in FIG. 8, and the colored surface of the dish washer becomes invisible. This is to confirm the completion of tightening.

Further, the one shown in FIGS. 9 and 10 disclosed in Japanese Utility Model Laid-Open No. 3-59586 discloses two rings having different diameters between the abutting portion provided on the main body and the end portion of the cap nut. Is designed to hold an adjustment ring that is integrally molded in a stepped manner. In the temporarily tightened state of FIG. 9, the nut is locked because it is clamped without deforming the adjustment ring, but in the fully tightened state with a wrench, the adjustment ring breaks from the stairs and overlaps as shown in FIG. The outer diameter on the smaller diameter side cannot be seen, and it is possible to confirm the completion of tightening the cap nut by full tightening.

Further, in the arrangements shown in FIGS. 11 and 12 disclosed in Japanese Utility Model Laid-Open No. 7-335037, an inner ring is attached to the outer periphery near the center in the axial direction following the male thread of the joint body, and the inner ring is attached. The outer ring that expands and contracts in the width direction is installed between the cap nut and the cap nut that is screwed into the male screw, and the inner ring and the outer ring collide with each other when the cap nut is not tightened by hand and the bag nut is tightened by hand. When the rotation of the nut is locked and the cap nut is fully tightened with a tool, the outer ring slides on the outer surface side of the inner ring when the cap nut is tightened to cover the outer surface of the inner ring and seal with the pipe. The connection is made. Further, when the outer ring has variations in the dimensions of the joint and pipe and is tightened with a regular tightening torque, an annular groove is provided on the outer peripheral surface to absorb the variation in the stop position of the cap nut, and the outer ring is stretchable in the width direction. It is designed to be able to hold.

[0006]

7 and 8 of the above-mentioned conventional technique.
In the conventional pipe joints disclosed in Japanese Utility Model Laid-Open No. 63-145089 and Japanese Utility Model Publication No. 3-59586 in FIGS. 9 and 10, the pipe is attached to the packing attached to the joint body with the cap nut hand tightened. The abutment seals the fluid in the tube. Therefore, there is a problem that it is not possible to confirm whether the cap nut is fully tightened by the leak test after construction. When the wrench is used for full tightening, the plate washer and adjustment ring are clamped between the abutting part of the main unit and the cap nut, and the cap nut is locked. There is a problem that the seal is incomplete depending on the size and the like. Further, in the case of FIGS. 7 and 8, since the end of the pipe abuts on the inner peripheral surface of the joint body or is attached and connected in a state of a minute gap, in the case of a pipe joint connecting a stainless pipe, the gap corrosion peculiar to stainless steel is caused. There is a problem that causes. Further, in the pipe joints shown in FIGS. 9 and 10, since the bite ring restrains the pipe, there is a problem that the pipe co-rotates as the cap nut is tightened.

Further, an actual flat blade 7-33 shown in FIG. 11 and FIG.
In the one disclosed in No. 5037, the inner ring and the outer ring do not have a large restraining force against loosening of the nut. In other words, the frictional force between the joint body and the nut end face depends on the tightening of the ring, but the outer ring has elasticity, so a large tightening frictional force cannot be obtained. There is a problem that the cap nut loosens when stress is applied to the pipe or joint. Further, since the inner ring and the outer ring are required, there is a problem that the number of parts increases and piping connection work becomes complicated. Further, since the cap nut is tightened while the pipe is pushed to the taper surface side of the cap nut by the packing, when the expansion base part of the pipe is expanded by the arcuate rounded surface, the expansion base part There is a problem that the outer surface comes into contact with the inner surface on the small diameter side of the cap nut, and the pipe rotates together with the tightening rotation of the cap nut.

The present invention solves the above problems, and it is possible to reliably confirm the tightening state of the cap nut in the hand tightened state and the tightened state.
In addition, the cap nut does not have a problem of loosening due to the binding force of the cap nut after full tightening, a large tightening force can be obtained, and there is no phenomenon of co-rotation of the pipe when tightening the cap nut. The present invention provides a pipe joint that does not cause skimmer corrosion peculiar to a stainless steel pipe even when connected with the airtightness.

[0009]

SUMMARY OF THE INVENTION The gist of the present invention is to provide a pipe having a flared flared portion at its end, a tapered outer peripheral surface at the end, and a joint main body having a screw following it. Following the screw, tighten the cap nut with the tapered inner peripheral surface to press the inner surface of the expanded portion of the pipe to the tapered outer peripheral surface of the joint body and connect it to the middle portion of the tapered outer peripheral surface of the joint body. An annular rubber packing was installed by providing a packing installation part, and a relief surface was provided on the small diameter side of the inner peripheral surface of the taper of the cap nut so that the flared expansion outer surface of the expansion base part did not contact. Is a pipe joint. In the above, the rubber packing is composed of an arcuate section and a band-shaped part extending toward the small diameter side, and the small diameter side end of the packing mounting portion provided on the taper outer peripheral surface has an outer diameter that does not contact the inner surface of the expanded portion of the pipe. It is a pipe joint in which a protrusion is provided and the rubber packing is attached. Further, in the above, the relief surface of the cap nut and the tapered inner peripheral surface can be connected with a smooth arc shape.

Further, in a pipe joint in which a male screw of a joint body and a female screw of a cap nut are screwed together to connect a pipe, an inner surface of a sliding contact which is in sliding contact with the joint body is provided on an inner surface of a front end portion of the female screw of the cap nut. , A sliding contact outer surface that is in sliding contact with the sliding contact inner surface of the cap nut is provided on the back side following the male screw of the joint body, and when the cap nut is tightened by hand on the joint body, a seal is created between the cap nut and the pipe. When the inner surface of the sliding contact of the cap nut is locked to the outer surface of the sliding contact of the joint body in a state where the cap nut is not tightened by hand, the cap nut is tightened by a tool. The inner surface of the sliding contact of the cap nut slides over the outer surface of the sliding contact of the joint body to cover the outer surface of the sliding contact, and frictional force acts between the outer surface of the sliding contact and the inner surface of the sliding contact It is a pipe joint characterized in that The degree of engagement between the outer surface of the sliding contact and the inner surface of the sliding contact can be provided on the tapered surface that gradually and strongly engages.

In the above, the sliding contact outer surface of the joint body can be colored with a color different from that of the joint body so that it can be easily discriminated from the outside whether or not the final tightening has been performed. Further, in the above, to one or both of the sliding contact outer surface of the joint body and the sliding contact inner surface of the cap nut, when the cap nut is tightened by hand tightening, locking and mutual tightening rotation is restricted, It is possible to provide a locking protrusion that allows the outer surface of the sliding contact and the inner surface of the sliding contact to slide when the main tightening is performed using a tool so that the cap nut is screwed. Also, in order to absorb variations in the final tightening completion position of the cap nut due to variations in the dimensions of the joint body, cap nut, and pipe, increase the number of cap nuts by providing a gap between the joint body and the end face of the cap nut after completion of final tightening. The structure can be tightened.

[0012]

The present invention has the above-mentioned structure, and since the inner surface of the cap nut is provided with a relief surface so as not to come into contact with the expansion base of the pipe, when the cap nut is tightened, The peripheral surface contacts only the tapered surface of the expanded part of the pipe,
Press the expanded part of the pipe toward the joint body. Therefore, since the pressing surface that presses the pipe is performed by the tapered surfaces, the inner circumference of the expanded portion of the pipe abuts the rubber packing attached to the joint and is locked by frictional force, and the tapered outer circumference of the expanded portion is tapered. Since they are pressed by contact with each other, they are slippery, and the rotational force of the cap nut is not transmitted to the pipe, so that the phenomenon of co-rotation of the pipe does not occur. When the cap nut is tightened, the inner surface of the expanded portion of the pipe is pressed against the tapered outer peripheral surface of the joint body, and the smaller diameter side contacts the rubber packing for sealing. A strip-shaped portion extending to the small diameter side of the rubber packing separates the pipe and the joint on the small diameter side through which the fluid passes, and prevents crevice corrosion. Further, since the annular protruding portion is formed at the small-diameter side end portion of the packing mounting portion, it is possible to prevent the rubber packing from falling off and the end portion of the packing from coming into contact with the end portion of the pipe and being damaged during connection construction.

Further, when the cap nut is temporarily tightened by hand tightening, the inner surface of the cap nut sliding contact abuts the outer surface of the joint main body so that rotation of the cap nut is restricted and screwing by hand tightening is locked. It When the cap nut is tightened by hand, internal fluid leaks from the connection part with the pipe, so when performing an airtight leak test after piping, it leaks from the connection point that is not fully tightened.
The defective connection can be detected reliably. Next, when the cap nut is fully tightened using a tool such as a wrench, the sliding contact inner surface of the cap nut locked in the hand tightened state rides on the sliding contact outer surface of the joint body and slides, The sliding contact outer surface of the joint body is covered and the sliding contact outer surface becomes invisible.

Since the seal connection with the pipe is completed by the full tightening of the cap nut, and the inner surface of the sliding contact of the nut covers the outer surface of the sliding contact of the main body, it is possible to confirm whether the cap nut is fully tightened after the installation. This can be done easily by making the external surface invisible. Further, in this fully tightened state, a large frictional force acts on the sliding contact portion between the joint body and the cap nut, and this frictional force prevents the cap nut from loosening, and a strong fastening force is obtained. The outer surface of the sliding contact is colored, making it easier to confirm tightening. Also, by providing the locking protrusion between the outer surface of the sliding contact and the inner surface of the sliding contact, the processing dimensional accuracy of the outer surface of the sliding contact, the inner surface of the sliding contact, and the pipe is absorbed, and the locking and rotation regulation in the hand tightened state are surely performed. The cap nut is restrained from being loosened by the joint body after being tightened and tightened.

[0015]

1 to 4 show an embodiment of the present invention. FIG. 1 shows a state in the middle of manual tightening, and FIG. 2 shows a state in which full tightening with a wrench is completed. Reference numeral 7 denotes a joint body, which is provided with a taper outer surface 71 that comes into contact with the inner surface of the flare portion 81 of the pipe 8 connected to the end, a packing groove 72 is provided in the taper outer surface 71, and a rubber packing 73 is attached. At the end of the packing groove 72 on the small diameter side, an annular protruding portion 75 having an outer diameter that does not contact the inner surface of the expanded portion of the pipe is provided to prevent the rubber packing 73 from falling off and the packing end portion from being damaged. A parallel male thread 74 is formed on the back side following the tapered outer surface 71, and the female thread 41 of the cap nut 4 is screwed into the male thread 74. A sliding contact outer surface 5 is provided on the back side of the male screw 74. Knurled eyes may be formed on the sliding contact outer surface 5. Sliding contact outer surface 5
Is 0, 1 to 0, 3 mm from the sliding inner surface 43 of the cap nut 4.
The sliding contact outer surface 5 is provided with a taper-shaped locking portion 51 at the entrance end of the sliding contact outer surface 5, and the cap nut 4 is locked to the locking portion 51 as shown in FIG. Hand tightening of 4 is completed. This hand tightening end position is set to the screwing position of the cap nut where the rubber packing 73 is not compressed and sealing is not performed as shown in FIG. The sliding contact outer surface 5 is colored with a paint such as red or blue for easy identification.

The cap nut 4 has a female screw 41 to be screwed into the male screw 74 of the joint body 7, a slidable inner surface 43 on the front end side thereof, and a taper inner surface 42 on the rear end side thereof.
The flared portion 81 of the pipe 8 is sandwiched between the tapered outer surface 71 of the main body and the tapered inner surface 42 of the cap nut by tightening the screw, and the rubber packing 73 fitted in the packing groove 72 of the tapered outer surface 71 contacts the flared portion 81 of the pipe. Sealed by touching,
A sealed connection with the tube 8 is made. A relief surface 44 is provided on the small diameter side of the tapered inner surface 42, and is connected to the tapered inner surface 42 by a smooth rounded surface. By this relief surface 44,
Even if the base outer surface 82 of the flare portion of the pipe 8 is expanded with a smooth curve, the flare base outer surface 82 does not contact the cap nut 4, but only the flare portion 81 that expands linearly. The cap nut 4 is tightened by smoothly sliding on the pipe 8.

In connection, first, as shown in FIG. 1, the flare portion 81 of the pipe 8 is engaged with the cap nut 4 to make the cap nut 4
When the screw is screwed onto the male screw 74 of the joint body 7 by hand-tightening,
As described above, the front end surface 21 of the sliding contact inner surface 43 of the cap nut hits the locking portion 51 at the end of the sliding contact outer surface 5 of the joint body, and the rotation of the cap nut 4 is restricted. I can't screw it. In this state, the flare portion 81 of the pipe as shown in FIG.
The inner surface of is not screwed with the rubber packing 73 and is in a screwed state where the sealing action with the pipe 8 is not performed. In this state, if a leak test is performed after construction, leakage will occur without fail and the connection point will be in an incomplete state. Can be definitely discovered.

Next, as shown in FIG. 2, when the cap nut 4 is fully tightened by using a pipe wrench or the like, the cap nut 4 is further screwed to the external thread 74 of the main body 7 by the tightening force of the wrench, and As shown in FIG. 4, the sliding contact inner surface 43 of the cap nut rises up and slides on the sliding contact outer surface 5 of the joint body. With the flare portion 81 of the pipe completely tightened by the tapered outer surface 71 and the tapered inner surface 42, the sliding contact inner surface 43 of the cap nut 4 covers the sliding contact outer surface 5, and the sliding contact outer surface 5 becomes invisible. By making the sliding contact outer surface 5 invisible, the tightening confirmation as to whether or not the cap nut is fully tightened and connected can be easily discriminated from the outside. The sliding contact outer surface 5 can be colored to facilitate further discrimination. In this state, the flare portion 81 of the pipe is sandwiched between the inner taper surface 42 of the cap nut and the outer taper surface 71 of the joint body, so that the sealing and retaining action with the pipe 8 works and a proper connection is made. , The sliding contact outer surface 5 and the sliding contact inner surface 4
The captive force of the cap nut 4 works by the frictional force between the cap nut 3 and the connection, and the cap nut 4 is connected.

The width of the sliding contact outer surface 5 is set so as to completely cover the lower limit of the variation range of the tightening completion position that occurs when the tightening is performed with the regular tightening torque. 5 can be completely covered with the slidable contact inner surface 43 of the cap nut, and construction confirmation can be reliably performed. Further, when the main tightening is completed, the cap nut 4 is prevented from being loosened by the frictional force of the sliding contact portion between the sliding contact outer surface 5 of the main body and the sliding contact inner surface 43 of the cap nut, and also against external stress such as vibration and impact. A large fastening force that does not loosen can be obtained. In particular, the outer diameter of the sliding contact outer surface 5 is slightly larger than the inner diameter of the sliding contact inner surface 43, or the outer diameter of the sliding contact inner surface 43 is increased in order, and knurls are provided on the outer surface of the sliding contact to increase the frictional force. Prevents the nut from loosening and obtains a large tightening force.
Further, since the cap nut 4 can be further tightened after the cap nut is fully tightened, a large binding force of the nut can be obtained even if there is a clearance gap between the abutting end faces of the main body and the cap nut.
It is possible to make a joint with a margin for additional tightening with respect to the seal.

Next, in the embodiment shown in FIGS. 5 and 6, the engaging projection 52 is provided on the sliding contact outer surface 5 of the joint body, and the engaging projection 45 is provided on the sliding contact inner surface 43 of the cap nut. This is an embodiment in which the locking in the hand tightened state is performed more reliably. When the cap nut 5 is screwed in by hand tightening, the locking projections 52 and 45 are locked and the screwing in hand tightening ends without being sealed. By tightening the cap nut 4 with a wrench, the locking projection 45 of the cap nut rides on the locking projection 52 of the joint body and further tightening proceeds, and the flare portion 81 of the pipe is clamped, and the sliding contact outer surface of the joint body 5 is covered, and the full tightening of the cap nut with a tool is completed. Also in this case, the inner surface of the locking projection 45 of the cap nut works with the sliding contact outer surface 5 of the joint body, and the outer surface of the locking projection 52 of the joint body works with the sliding contact inner surface 45 of the cap nut. Move in sliding contact.

In the case of the present embodiment, the locking projections 45 and 52 ensure the locking in the hand-tightened state, and after the locking projections 45 and 52 are overcome in the final tightened state using the wrench. Since the tightening torque can be adjusted and reduced, reliable main tightening can be performed, and the dimensional accuracy of the sliding contact inner surface 43 and the sliding contact outer surface 5 is absorbed, so that the sliding contact inner surface 43 and the sliding contact outer surface 5 are absorbed. The dimensional accuracy of can be relaxed. The locking protrusions 45 and 52 are formed on the outer surface 5 of the joint body that is in sliding contact.
Alternatively, it may be provided on either one of the slidable contact inner surfaces 43 of the cap nut, or a gentle slope may be provided at the portion where the locking projections 45, 52 abut with each other to facilitate overcoming during the final tightening.

[0022]

As described above, according to the present invention, it is possible to reliably confirm the hand tightened state and the fully tightened state of the cap nut.
In addition, the cap nut after full tightening has a restraining force, and after connection, a large tightening force that does not loosen the cap nut is obtained, and there is no phenomenon of pipe co-rotation when tightening the cap nut. Even when the pipes are connected, airtightness and skimmer corrosion peculiar to stainless steel pipes do not occur. Furthermore, it is a pipe joint that can easily detect connection points where the tightening has been forgotten in a leak test after pipes have been applied.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of an embodiment of the present invention in a hand-tightened state.

FIG. 2 is a partial cross-sectional view of an embodiment of the present invention in a final tightened state.

FIG. 3 is a partial cross-sectional view of a cap nut and a joint body in a hand-tightened state.

FIG. 4 is a partial cross-sectional view of a cap nut and a joint body in a fully tightened state.

FIG. 5 is a partial cross-sectional view of another embodiment of the present invention in a hand-tightened state.

FIG. 6 is a partial cross-sectional view showing a further tightened state of another embodiment of the present invention.

FIG. 7 is a sectional view showing a conventional technique in a hand-tightened state.

FIG. 8 is a cross-sectional view of the fully tightened state of FIG. 7.

FIG. 9 is a cross-sectional view of another conventional technique in a hand-tightened state.

FIG. 10 is a cross-sectional view of the fully tightened state of FIG.

FIG. 11 is a cross-sectional view of another conventional technique in a hand-tightened state.

FIG. 12 is a cross-sectional view of the fully tightened state of FIG. 11.

[Explanation of symbols]

4 Cap nut 5 Sliding contact outer surface 7 Joint body 8 Pipe 41 Female thread 42 Tapered inner surface 43 Sliding contact inner surface 44 Relief surface 45 Cap nut locking protrusions 21, 51 Locking portion 52 Joint main body locking protrusion 72 Packing groove 73 Rubber Packing 74 Male thread 75 Annular protrusion 81 Pipe flare 82 Flare base

Claims (2)

(57) [Claims] 1. A tube having a flared widened portion at its end,
Tighten with a tapered outer peripheral surface at the end and a joint body with a thread following it, and a female nut followed by a cap nut with a tapered inner peripheral surface. In a pipe joint that press-connects, a packing mounting portion is provided in the middle of the tapered outer peripheral surface of the joint body to mount an annular rubber packing, and the flare of the pipe is attached to the small diameter side of the tapered inner peripheral surface of the cap nut. A pipe joint characterized in that a relief surface is provided so that the outer surface of the expansion base portion that expands like a circle does not contact. 2. The rubber packing is composed of an arc section in cross section and a band-shaped section extending toward the small diameter side, and a small diameter side end of a packing mounting portion provided on the taper outer peripheral surface does not contact the inner surface of the expanded portion of the pipe. The pipe joint according to claim 1, wherein the rubber packing is mounted by providing an annular protrusion having an outer diameter.