JP3918099B2 - Pipe detachment prevention device for union nut joint and disassembly method - Google Patents

Description

  The present invention relates to an expansion / contraction flexible pipe joint of a type in which a pipe end portion of a joint pipe not engraved with a screw is inserted into a receiving portion of a pipe or a joint body and is fastened with a union nut with a rubber packing interposed therebetween. The present invention relates to a pipe detachment preventing device and a pipe joint disassembling method.

  As a technique for constructing a pipe joint by inserting a pipe end part of a joining pipe into a receiving part of a pipe or a joint main body and interposing a rubber packing, the one disclosed in Japanese Patent Application Laid-Open No. 2005-151867 is known. In the technology of Patent Document 1, a semi-circular two-piece piece is used, and a retaining ring of a type in which flange portions facing each other are fastened with bolts is used as an outer peripheral surface of an insertion tube (joining tube). It is fixed on the top. Then, a semi-annular protrusion is locked from each of the split pieces of these retaining rings to an annular protrusion provided on the outer peripheral surface of the receiving tube, thereby preventing the insertion tube from coming off.

However, in the type in which the retaining ring is composed of two split pieces, the bolt and nut fastening portion of the retaining ring and the inner dimension in the perpendicular direction are smaller than the outer diameter of the insertion tube, If the nut fastening portion and the horizontal direction are not larger than the outer diameter of the insertion tube, the tube cannot be inserted and fixed. Therefore, the pipe end side of the inlet tube cannot be inserted as it is into the joint body and the retaining ring shipped from the factory with the half-piece retaining ring temporarily tightened, and the retaining ring bolt and nut It was necessary to insert the bolt in a loosened state and then fasten the bolt and nut again, which required a lot of labor. In addition, there are two disadvantages that there are two tightening points, and it takes time to tighten bolts and nuts.
In short, the technology using the split piece retaining ring described in Patent Document 1 has a drawback in that it takes time for the joint construction work.

Therefore, the present applicant has already developed the technique described in Patent Document 2. In the technique described in Patent Document 2, a non-threaded joining pipe is inserted into a joint body having a receiving part in which an external thread is engraved on the outer peripheral surface, and a union nut is screwed and tightened to the receiving part. Yes. A halfway on the outer peripheral surface is cut out, and a retaining ring is prepared that is externally fitted to the joining pipe on the rear end side of the union nut and tightened by a bolt and a nut. On both left and right side surfaces on the outer peripheral surface of the retaining ring, an arm is formed integrally with the retaining ring so as to protrude toward the union nut. By engaging the arm with an annular recess provided on the union nut, , Preventing the separation of the tube. In addition, a plastic ring externally fitted to the annular recess of the union nut is provided with a portion for holding the arm so that the center position of the retaining ring does not shift during temporary fixing.
According to the invention of the prior application described in Patent Document 2, the center position of the retaining ring is not displaced by the plastic ring, and the operation of inserting the joining pipe in the field is easy.
Japanese Utility Model Publication No. 49-81417 JP 2003-214575 A

  However, in the technique described in Patent Document 2, a plastic ring is indispensable for facilitating the insertion operation of the joining pipe. Therefore, it is necessary to prepare and manage a plastic ring for each part number having a different pipe outer diameter, which is extremely complicated and causes high costs. Even if there is a plastic ring, the retaining ring may be inclined due to gravity and the center position may be shifted, and the joining tube may not be inserted smoothly.

  Furthermore, in the technique of Patent Document 2, when a pipe detachment force acts on the joining pipe, the notched portion provided in the middle on the outer peripheral surface of the retaining ring has the highest strength in the entire circumference of the retaining ring. There is no part, and it is not connected to the union nut side. On the other hand, since the part with the arm is connected and is strong in strength, the part with the notch is pulled by the tube detachment force, and as a result, the retaining ring makes the notch part the center of the bend There was a drawback that it was deformed like a square and could not withstand a large separation force.

  On the other hand, the pipe joint may be disassembled after construction and replaced with new pipes or maintenance may be performed, but normally, the retaining ring is permanently deformed and does not leave the joined pipe. Therefore, insert a special tool into the notch provided on the outer peripheral surface of the retaining ring, widen the notch of the retaining ring to increase the diameter, and release the retaining ring from the tight contact with the joint pipe. I had to. In other words, in order to disassemble the pipe joint, it was necessary to prepare for producing a dedicated tool.

  Also, in the case of connecting a buried pipe in a straight part, the thrust load due to water pressure is prevented from detachment due to the frictional resistance between the pipe and the soil, so there are some sites where the pipe detachment prevention fitting is not required for the joint. In such a place, the retaining ring must be removed from the factory-shipped state in which the retaining ring and the union nut are temporarily tightened. However, in the technique of Patent Document 2, there is a procedure for removing the retaining ring after first removing the plastic ring covering the arm of the retaining ring. There was a drawback that it took a great deal of effort to remove.

  The present invention is a further improvement of the technology previously filed by the present applicant in view of the above-mentioned problems, and it is easy to insert a joining tube even without a plastic ring, and exhibits a high detachment prevention function. It is an object of the present invention to provide a tube detachment preventing device that can be used and a method that can be easily disassembled.

  The means of claim 1 employed by the present invention to solve the above-described problem is that a non-threaded joining pipe is inserted into a pipe or joint body having a receiving portion in which an external thread is engraved on the outer peripheral surface, and an annular rubber In a pipe joint that has a structure in which a packing is inserted and inserted and a union nut is screwed and tightened to the receiving portion, a part on the outer peripheral surface is cut off and is fitted to a joint pipe on the rear end side of the union nut. A retaining ring tightened by a bolt and a nut, and an arm that is integrally formed with the retaining ring and engages with an annular recess provided in the union nut. And a pipe detachment preventing device for a union nut joint, which is provided at a total of four positions on opposite side surface portions on the outer peripheral surface of the retaining ring with the both end portions as intermediate positions.

  According to the second aspect of the present invention, a locking member that contacts the outer peripheral surface of the union nut is detachable or used on the outer peripheral surface opposite to the positions of both ends of the retaining ring. 2. The pipe detachment preventing device for a union nut joint according to claim 1, wherein the pipe detachment preventing apparatus is attached so as to be able to take a position and a non-use position.

According to the third aspect of the present invention, a non-threaded joining pipe is inserted into a pipe or joint body having a receiving portion with an external thread engraved on the outer peripheral surface, and an annular rubber packing is inserted and interposed. A union nut is screwed and tightened to the receiving part, and a retaining ring that is notched on the outer peripheral surface is tightened to a joining tube on the rear end side of the union nut, and a tube is inserted between the retaining ring and the union nut. A method of disassembling a pipe joint that incorporates a mechanism for preventing detachment, wherein the dimensions of both ends of the retaining ring that are notched are extended in the direction of the tube axis, and the ends that are notched between the extensions are Between the two ends, by inserting a flat plate portion of the simple dismantling tool from the direction perpendicular to the tube axis and rotating the simple dismantling tool about the vertical direction. Enlarge at the moving plate-shaped part, and then expand the retaining ring to see if it is in close contact with the joined tube Is obtained by such release, as the simple dismantling tool, the corner of the flat portion other pair of corner edges shaped with a set of corners in the diagonal have become R surface and a planar portion In addition, when the simple dismantling tool is rotated, the flat plate portion is formed on each of both end portions of the retaining ring. The union nut joint disassembling method is characterized in that after passing through the state in which the respective R surface portions are brought into contact with each other, the flat portions are brought into contact with each other to enlarge the dimension between the both end portions .

  According to the first aspect of the present invention, in the temporarily fixed state shipped from the factory, a total of four arms provided on both end portions where the retaining ring is notched and both side surface portions of the retaining ring are engaged with the annular recess of the union nut. As a result, the center of the retaining ring coincides with the center position of the union nut or the like, and the insertion work of the joining tube is easy. In addition, because the arm is provided at both ends of the retaining ring and engaged with the annular recess of the union nut, the notched portion of the retaining ring is deformed into a dogleg shape when the release force is applied. And high detachment prevention power can be obtained.

  Further, in the invention of claim 2, since the locking member that contacts the outer peripheral surface of the union nut is detachably attached to the outer peripheral surface on the opposite side to the positions of both ends of the retaining ring, After the insertion tube is inserted into the retaining ring, etc., the retaining ring bolt and nut can be fastened at any position without falling off even if the retaining ring is rotated on the outer peripheral surface of the insertion tube. Is possible.

  Furthermore, the invention of claim 3 improves the difficulty that the retaining ring is permanently deformed after construction and cannot be disassembled. That is, the dimensions in the tube axis direction of both ends of the retaining ring notched are extended, and the simple dismantling tool from the direction perpendicular to the tube axis from between the extended portions to between the notched ends. The flat plate portion is inserted. Then, by rotating the simple dismantling tool about the vertical direction, the dimension between the cut-out ends of the retaining ring is enlarged and opened at the flat plate-like portion. Once the gap between both ends is opened, the inner diameter of the retaining ring is enlarged, and the retaining ring can be easily removed from the joint tube. The opening between both end portions can be opened to a size exceeding the width of the retaining ring, and a simple dismantling tool can be shared for the retaining rings of each nominal diameter. Thus, in the present invention, it is possible to disassemble the post-construction retaining ring that has been permanently deformed with a simple jig.

In the invention of claim 3 , the corner of the flat part of the simple dismantling tool is such that one set of corners on the diagonal line is an R surface part and a flat part, and another set of corners is formed in an edge shape. Therefore, the rotation operation of the simple dismantling tool can be facilitated, and the release and fixation can be stabilized.

  The configuration of the present invention will be described below based on the best mode shown in the drawings. 1 to 4 show a pipe detachment preventing device 1 for a union nut joint according to a first embodiment of the present invention, in a state where a pipe is inserted and connection fastening is completed. 1 is a side view of the pipe detachment preventing device 1, FIG. 2 is a front view thereof, and FIG. 3 is a plan view thereof. 4A to 4C are cross-sectional views taken along lines AA, BB, and CC, respectively, in FIG. As shown in the figure, the pipe detachment preventing device 1 includes a C-shaped retaining ring 2 that is cut off on the outer circumferential surface, and a bolt 4 that fastens the retaining ring 2 onto the outer circumferential surface of the joining pipe 3. And a nut 5 and an arm 7 for connecting the retaining ring 2 and the union nut 6. The arm 7 is cast-molded integrally with the retaining ring 2 and is opposed to the both ends 2A, 2B of the retaining ring 2 on the outer peripheral surface of the retaining ring with the both ends 2A, 2B being at intermediate positions. There are a total of four locations on both sides. A hook 8 that protrudes in the inner diameter direction is formed at the tip of each arm 7. In addition, the code | symbol 9 is a coupling main body or a receiving pipe in the figure.

  Thus, by casting the arm 7 integrally with the retaining ring 2, the conventional locking ring shown in Patent Document 2 can be omitted, and the production thereof is performed simultaneously with the production of the retaining ring 2. Since this can be done, one casting operation can be omitted. A serrated anti-slip portion 10 (see FIGS. 4A to 4C in FIG. 4) is provided on the inner peripheral surface side of the retaining ring 2 to improve the biting into the outer peripheral surface of the joining tube 3. Is formed.

  On the other hand, an annular recess 11 for engaging with the hook 8 of the arm 7 is formed on the end face side of the union nut 6 from the joining pipe 3. Even before and after tightening, the inner diameter dimension of the hook 7 is set to be smaller than the outer diameter dimension of the convex portion 12 near the end surface constituting the annular recess 11, and the outer diameter dimension of the annular recess 11. Is set larger than.

The union nut joint pipe detachment preventing device 1 configured as described above is cast-molded at a factory, temporarily assembled as necessary, and shipped in this state. In the temporary assembly, first, as shown in FIGS. 4A to 4C, the packing 13 is inserted into the inner peripheral surface side of the union nut 6, and the whole is screwed to the joint body 9. . That is, the union nut 6 is screwed to the male screw portion formed on the outer peripheral surface of the joint body 9. Subsequently, the retaining ring 2 in a state where the bolt 4 and the nut 5 are temporarily tightened is prepared, and the hook 8 on the tip side of each arm 7 integrally formed with the retaining ring 2 is directly above the annular recess 11 of the union nut 6. Arrange to position. Then, from this state, the retaining ring 2 is lowered in a direction perpendicular to the paper surface of FIG. 3 so that the hook 8 at the tip of the arm engages with the annular recess 11 of the union nut 6.
In this way, the retaining ring 2 is simply loaded from above and can be easily and quickly performed. Further, the retaining ring 2 mounted on the union nut 6 has a center line that coincides with the axial center line of the pipe joint, so that it is very easy to insert the joining pipe 3 described later.

  After that, the whole may be wrapped with a film or packed in a bag of vinyl or the like before shipment. Depending on the contractor, there is also a request for shipping in a disassembled state without temporary assembly. In such a case, all parts of the pipe detachment prevention device 1 are disassembled without being temporarily assembled. Shipped in bags. Thereby, the temporary assembly of the pipe detachment preventing device 1 is completed.

  At the construction site, the joining pipe 3 is inserted into the temporarily detached pipe detachment preventing apparatus 1. Since the central axes of the retaining ring 2, the union nut 6, the packing 13, and the joint main body 9 coincide with each other in the temporarily assembled state, the insertion opening on the distal end side of the joining pipe 3 is connected to the retaining ring 2 side. Is simply inserted through the union nut 6 and packing 13 to reach into the joint body 9, which is extremely easy. After that, after confirming that the union nut 6 has been tightened to the minimum tightening torque necessary for water tightness with a spanner or a pipe wrench, the fastening portion of the retaining ring 2 can be easily tightened (the fastening portion is upward). After tightening it so that it comes to the position), tighten it again. Finally, the retaining ring 2 is fastened. The fastening of the retaining ring 2 is performed after the axial positioning with respect to the joining pipe 3 and the direction of the bolt fastening portion (positioned upward as shown in FIGS. 1 to 3) are determined, and then the bolt 4 and the nut 5 are connected. What is necessary is just to carry out so that the saw-tooth 10 engraved in the inner peripheral surface of the retaining ring 2 may bite into the outer peripheral surface of the joining pipe | tube 3, and a non-slip function may be exhibited. Thereby, the joining tube 3 can be expanded and contracted within a range in which the hook 8 can move in the annular recess 11.

  Further, after construction, even if a force in the tube detachment direction is applied between the joint tube 3 and the joint body 9, the arms 7 and 7 are provided at both ends 2A and 2B where the retaining ring 2 is notched. Since the hooks 8 and 8 at the tips thereof are engaged with the annular recess 11 of the union nut 6, both end portions 2A and 2B cut out of the retaining ring 2 are deformed into a dogleg shape by the detachment force. There is no need to do so, and a high ability to prevent separation is obtained.

  On the other hand, this union nut joint pipe detachment preventing device 1 may be disassembled and reassembled after construction. The disassembly is performed by disassembling the retaining ring 2 and then unscrewing the union nut 6 and pulling out the joining tube 3. However, once assembled, the retaining ring 2 is permanently deformed. For this reason, the retaining ring 2 cannot be separated from the joint tube 3 unless it is opened after using a special tool. In the present embodiment, the dimensions of both ends 2A and 2B of the retaining ring 2 that are notched are extended (substantially the structure of the arm 7), and are notched between the extensions. A flat plate-shaped simple disassembling tool 14 shown in FIGS. 16A to 16C is inserted between the two end portions 2A and 2B so that the retaining ring 2 is opened. The simple dismantling tool 14 includes a hexagonal head portion 14A and a flat plate portion 14B. The thickness dimension T of the flat plate portion 14B is a snap ring that is slightly opened when the bolts and nuts are loosened after final tightening. 2 is smaller than the distance between the two end portions 2A and 2B, the width W is set smaller than the total length L of both ends 2A and 2B, and the inner diameter of the retaining ring is set to be larger than the outer diameter of the pipe. . The corners of the flat plate portion 14B are such that a pair of corners on a diagonal line are an R surface portion and a plane portion, and the other pair of corners are formed in an edge shape. This is for facilitating the insertion, for facilitating the turning operation, and for stabilizing the release and fixation. Compared to the width of the retaining ring, the cut-out ends 2A and 2B are longer in the tube axis direction, so there is no need to set the dimensions of the simple dismantling tool for each nominal diameter. It can be used for many nominal diameters.

  Therefore, as shown in FIG. 17A, first, the tightening bolt 4 and the nut 5 are loosened. Next, the flat part 14B of the simple dismantling tool 14 is inserted between the extension parts (arms 7 and 7) of the both end parts 2A and 2B of the retaining ring 2 (see the state of FIG. 5B). Subsequently, as shown in FIG. 5C, the simple dismantling tool 14 is rotated with a hexagon wrench or the like. Thereby, the dimension between the both ends 2A and 2B where the retaining ring 2 is notched is enlarged. Since the simple dismantling tool 14 is flatter than the R-surface corner of the flat plate-like portion 14B, the retaining ring 2 is in a state in which the width between the two end portions 2A and 2B is expanded to the width W of the flat plate-like portion 14B. Stabilize. The dimension W is set so that the inner diameter of the retaining ring 2 is larger than the outer diameter of the pipe in the state shown in FIG. Can do. Thus, in the present invention, it is possible to disassemble the post-construction retaining ring 2 that has been permanently deformed with a simple jig 14. The released retaining ring 2 and the simple dismantling tool 14 are in a set state, but when reconstructing, the pipe is inserted as it is, and the simple dismantling tool 14 is rotated in the direction opposite to that when disassembling. Can be reused.

  Next, a pipe detachment preventing device 15 for a union nut joint according to a second embodiment of the present invention will be described with reference to FIGS. 5 is a side view of the tube detachment preventing device 15, FIG. 6 is a front view thereof, FIG. 7 is a bottom view showing the operating state of the locking member 16, and FIG. It is a bottom view. 9A is a side view of the locking member 16, and FIG. 9B is a bottom view thereof. Moreover, the figure (C) of the figure is a side view which shows another locking member 16, and figure (D) is the bottom view.

  As shown in each of these drawings, in this pipe detachment preventing device 15, the bottom surface side of the retaining ring 2 (the side opposite to the both end portions 2A and 2B) is shown in FIGS. A locking member 16 as shown in (D) is detachably attached. As the material of the locking member 16, a plastic such as polypropylene or polyethylene is sufficient. The locking member 16 shown in FIG. (A) and FIG. (B) includes a flat plate portion 16A whose tip is slightly narrowed and chamfered, and a mushroom-shaped protrusion portion 16B formed to protrude from the base side of the flat plate portion 16A. Become. The locking member 16 shown in FIGS. (C) and (D) has a reinforcing rib 16 </ b> C formed on the surface of the flat plate portion 16 </ b> A opposite to the surface on which the protrusion 16 is formed. The locking member 16 is attached to the retaining ring 2 by forming a small hole (not shown) on the outer peripheral surface of the retaining ring 2 on the side opposite to the notched both ends 2A and 2B. On the other hand, the mushroom-like protrusion 16B of the locking member 16 is press-fitted.

  In the pipe detachment preventing device 15 configured as described above, first, the retaining member 16 is held in the state of FIG. 8, and the retaining ring 2 is fitted and attached to the union nut 6. The mounting procedure is the same as that in the first embodiment described above, and only a simple operation is required to lower the retaining ring 2 from above. After the mounting, as shown in FIGS. 5 to 7, the locking member 16 is rotated so that the flat plate portion 16 </ b> A abuts or separates from the outer peripheral surface of the annular convex portion 12 of the union nut 6. . As a result, the retaining ring 2 is not dropped off in any direction, and can be directed to any position where the fastening operation of the bolt 4 and the nut 5 is easy. After that, the tip end side of the joining pipe 3 may be inserted from the retaining ring 2 side through the union nut 6 and the packing 13 to reach the joint body 9 side.

  With such a tube detachment preventing device 15, when the temporary assembly is performed and the product is shipped from the factory, the retaining ring 2 does not fall off the union nut 6 due to the action of the locking member 16, so the whole is made of a film. It is possible to omit covering or putting in a plastic bag. Further, the other configuration and operational effects of the tube detachment preventing device 15 are the same as those of the device 1 of the first embodiment.

  10 to 12 show a tube detachment preventing device 17 according to a third embodiment of the present invention. FIG. 10 is a bottom view of the device 17, FIG. 11 is a front view thereof, and FIG. A) is a side view of the locking member 18, and FIG. (B) is an end view of the member 18. In this locking member 18, the locking member 16 of the second embodiment is changed to a rod-shaped member having a serration 19, and a flange 20 is erected on the outer peripheral surface of the retaining ring 2 to fix the locking member 18. A serration hole 21 for insertion is provided. The retaining ring 2 is removed or attached by taking in and out the locking member 18. The locking member 18 may be plastic or a spring pin. About another structure and an effect, it is the same as the case of the said 1st and 2nd embodiment.

  13 to 15 show a tube detachment preventing device 22 according to a fourth embodiment of the present invention. FIG. 13 shows one of the tube detachment preventing devices 22 after the locking member 23 is attached. 14 is a bottom view of the tube detachment preventing device 22 showing a state in the middle of mounting the locking member 23, and FIG. 15A is a side view of the locking member 23. FIG. B) is an end view of the member 23. As shown in the figure, the locking member 23 is formed by integrally forming a hemispherical head 24 on one end side of the rod-shaped locking member 18 of the third embodiment. The operational effects and other configurations and operational effects of the locking member 23 are the same as those in the above embodiments.

  By the way, this invention is not limited to embodiment mentioned above, A suitable change is possible. For example, the locking member 16 has been described as being detachable and rotating, and the locking member 18 has been described as being detachably inserted into the small hole. It may be of a type that is fixed by, for example. What is important is that the locking member is configured to engage with the union nut 6 in the use position and release the engagement with the union nut 6 in the non-use position.

It is a side view showing the whole pipe detachment prevention device concerning a 1st embodiment of the present invention. It is a front view of the pipe detachment prevention device concerning a 1st embodiment of the present invention. It is a top view of the pipe detachment prevention device concerning a 1st embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a tube detachment preventing device according to a first embodiment of the present invention, in which FIG. (A) is a cross-sectional view taken along line AA in FIG. 2, and FIG. (C) is the CC sectional view taken on the line. It is a side view which shows the whole pipe detachment | leave removal prevention apparatus which concerns on the 2nd Embodiment of this invention. It is a front view showing the whole pipe detachment prevention device concerning a 2nd embodiment of the present invention. It is a bottom view of the pipe detachment preventing device according to the second embodiment of the present invention and showing the operating state of the locking member. It is a bottom view of the pipe detachment preventing device according to the second embodiment of the present invention and showing the non-operating state of the locking member. The locking member which concerns on the 2nd Embodiment of this invention is shown, A figure (A) is a side view of a locking member, and a figure (B) is the bottom view. Moreover, the figure (C) of the figure is a side view which shows another locking member, and figure (D) is the bottom view. It is a side view of the pipe detachment prevention device concerning a 3rd embodiment of the present invention. It is a front view of the pipe detachment prevention device concerning a 3rd embodiment of the present invention. FIG. 4A is a side view of a locking member, and FIG. 4B is an end view of the locking member according to a third embodiment of the present invention. It is a bottom view which shows a part of pipe detachment prevention device concerning a 4th embodiment of the present invention. It is a bottom view of the pipe detachment preventing device according to the fourth embodiment of the present invention and showing a state in the middle of mounting the locking member. FIG. 4A is a side view of a locking member, and FIG. 4B is an end view of the member according to a fourth embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS The simple dismantling tool which concerns on this invention is shown, A figure (A) is the side view, A figure (B) is a bottom view, A figure (C) is the figure which rotated the front view 90 degree | times clockwise. FIG. 1A shows a usage state of a simple dismantling device according to the present invention, and FIG. 1A is a plan view showing a space between both end portions of a retaining ring before use, and FIG. FIG. 4C is a plan view showing a state in which the simple dismantling tool is rotated to increase the distance between both ends of the retaining ring.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,15,17,22 ... Pipe detachment prevention device, 2 ... Retaining ring, 3 ... Joint pipe, 4 ... Bolt, 5 ... Nut, 6 ... Union nut, 7 ... Arm, 8 ... Hook, 9 ... Joint body, 11 ... Annular recess of union nut, 12 ... annular protrusion, 13 ... packing, 14 ... simple dismantling tool, 16, 18, 23 ... locking member

Claims (3)

Insert a screw-free joining tube into a pipe or joint body with a receiving part with a male thread engraved on the outer peripheral surface, insert an annular rubber packing, and tighten the union nut to the receiving part. In a pipe joint with a structure, a halfway on the outer peripheral surface is cut off, and a retaining ring that is externally fitted to the joining pipe on the rear end side of the union nut and tightened with a bolt and nut is formed integrally with the retaining ring. And an arm that engages with an annular recess provided in the union nut. The arm includes both ends of the retaining ring that are notched, and opposite side surfaces on the outer peripheral surface of the retaining ring with the both ends serving as intermediate positions. A pipe detachment prevention device for a union nut joint, which is provided at a total of four locations. On the outer peripheral surface opposite to the position of both ends of the retaining ring, the locking member that comes into contact with the outer peripheral surface of the union nut is attached so that it can be removed or used and can be used and not used. The pipe separation preventing device for a union nut joint according to claim 1. Insert a screw-free joining tube into a pipe or joint body with a receiving part engraved with an external thread on the outer peripheral surface, insert and insert an annular rubber packing, and screw and tighten a union nut on the receiving part. Dismantling of pipe joints that incorporate a mechanism that prevents the pipe from being detached between the retaining ring and the union nut by tightening the retaining ring that is cut off on the outer peripheral surface of the joining pipe on the rear end side of the union nut. A method of extending the dimension of the both ends of the retaining ring notched in the tube axis direction, and extending from between the extended portions between the notched ends from the direction perpendicular to the tube axis. By inserting the flat part of the simple dismantling tool and rotating the simple dismantling tool about the vertical direction, the dimension between the two end parts is enlarged at the flat part, and then It is obtained by so as to release the adhesion state between the joint tube by expanding the retaining ring, before As a simple dismantling tool, the corners of the flat plate portion are diagonally set with a pair of corners being an R surface portion and a flat surface portion, and another set of corners is formed in an edge shape. When the simple dismantling tool is rotated using both ends of the short side formed in flat portions, the R surface portions of the flat plate portion are brought into contact with both end portions of the retaining ring. A method for disassembling a union nut joint , wherein the flat portions are brought into contact later to enlarge the dimension between the two end portions .

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