Pipe joint and pipe joining method

Abstract

To provide a pipe joint which can make a user aware of the erroneous attachment of a lock ring before the execution of pipe insertion work when an orientation of the lock ring is erroneously set in a reverse orientation.SOLUTION: Both end faces of a lock ring 8 having a one-split structure have engagement parts 32a with which an interval maintenance jig 123 for maintaining an interval between both the end faces of the lock ring 8 which is expanded in a diameter by a diameter-expansion jig 101 can be engaged, at least either of single end faces 32 of the lock ring 8 has an escape part 45 for making the interval maintenance jig 123 escape to a release direction 44 in which the interval maintenance jig is released to the inside of a radial direction of the lock ring 8 from the end face 32 of the lock ring 8, and when the lock ring 8 is accommodated in a lock ring accommodation groove 7 in a regular orientation, the engagement part 32a is located at an opening end face 14 side of a receptacle 5, and in a state that the escape part 45 is located at a depth end side of the receptacle 5, and the lock ring 8 is expanded in the diameter, the engagement part 32a and the escape part 45 are exposed to the inside of the radial direction from the lock ring accommodation groove 7.SELECTED DRAWING: Figure 18

Description

[Technical field]

[0001] The present invention relates to a pipe joint in which the insertion port of one pipe is inserted into the receiving port of the other pipe and has a function of preventing disengagement, and to a method of joining pipes. [Background technology]

[0002] Conventionally, as shown in Figures 20 and 21, there has been a pipe fitting of this type in which an insertion port 202 of one pipe 201 is inserted into a receiving port 204 of the other pipe 203, a lock ring accommodating groove 205 is formed on the inner circumference of the receiving port 204, a lock ring 206 is accommodated in the lock ring accommodating groove 205, and an insertion port protrusion 207 is formed on the outer circumference of the tip of the insertion port 202, and the insertion port protrusion 207 engages with the lock ring 206 from the rear side of the receiving port 204 in the removal direction 208 of the insertion port 202, thereby preventing the insertion port 202 from coming out of the receiving port 204.

[0003] The gap between the inner periphery of the socket 204 and the outer periphery of the insertion port 202 is sealed with a rubber ring 209 , and the rubber ring 209 is pressed toward the back of the socket 204 by a pressure ring 210 .

[0004] The side surface of lock ring accommodating groove 205 on the socket opening side is formed as tapered surface 211. Lock ring 206 is a ring with a single split structure having a split portion (not shown) where one portion is split, which allows the diameter of lock ring 206 to be enlarged or reduced. The side surface of lock ring 206 on the socket opening side is formed as tapered surface 213.

[0005] In the pipe fitting 200 as described above, when joining one pipe 201 and the other pipe 203, the lock ring 206 is set in the lock ring accommodating groove 205 in the receiving port 204, the lock ring 206 is expanded using a diameter expansion jig (not shown), a gap maintaining jig (not shown) is set at the divided portion of the lock ring 206 in the expanded diameter state, and the diameter expansion jig is removed from the lock ring 206, and the gap between the both end faces at the divided portion of the lock ring 206 in the expanded diameter state is maintained by the gap maintaining jig.

[0006] 21, when the orientation of lock ring 206 is set correctly, lock ring 206 is maintained in an expanded state and is stored all the way into lock ring accommodating groove 205. Thereafter, by inserting insertion port 202 into socket 204, insertion port protrusion 207 passes along the inner periphery of lock ring 206 from the open end face side of socket 204 to the back end side.

[0007] Furthermore, as shown in Figure 22, if lock ring 206 is mistakenly set in the opposite direction, lock ring 206 will be maintained in an expanded diameter state, but since outer circumference 206a of lock ring 206 comes into contact with tapered surface 211 of lock ring accommodating groove 205, lock ring 206 cannot be accommodated all the way in lock ring accommodating groove 205 and insertion port protrusion 207 will get caught on lock ring 206 protruding from lock ring accommodating groove 205, making it impossible for insertion port 202 to be inserted into receiving port 204.

[0008] This makes it possible to prevent erroneous joining when joining one tube 201 and the other tube 203 together.

[0009] Incidentally, the above-mentioned pipe joint is described, for example, in Patent Document 1 below, and the diameter expansion jig and the gap maintaining jig are described, for example, in Patent Document 2 below. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Patent Publication No. 2004-232679 [Patent Document 2] Patent No. 4446805 Summary of the Invention [Problem to be solved by the invention]

[0011] However, in the above conventional type, as shown in Figure 22, if the lock ring 206 is set in the wrong direction when joining pipes 201, 203 together, it is not possible to realize that lock ring 206 has been installed incorrectly until the pipe insertion work of inserting insertion port 202 into receiving port 204 is performed, and as a result, there is a problem in that it takes time to redo the joining work of pipes 201, 203.

[0012] The present invention aims to provide a pipe fitting and a pipe joining method that, when the lock ring is mistakenly set in the reverse direction, makes it possible to notice that the lock ring has been incorrectly installed before pipe insertion work is performed. [Means for solving the problem]

[0013] In order to achieve the above object, the first invention provides a pipe fitting in which the insertion port of one pipe is inserted into the receiving port of the other pipe, A lock ring receiving groove is formed on the inner circumference of the socket. The lock ring is accommodated in the lock ring accommodating groove, An engagement body is formed on the outer periphery of the insertion port, A pipe fitting capable of preventing the insertion port from being removed from the socket by an engagement body engaging with a lock ring from a back side of the socket in a removal direction of the insertion port, The lock ring is a ring with a single split structure having a split portion at one point, Both end faces of the lock ring in the circumferential direction have engagement portions with which a gap maintaining jig can be engaged that maintains the gap between the both end faces of the lock ring expanded by the diameter expanding jig, At least one end face of the lock ring has a relief portion that allows the gap maintaining jig to escape in a detachment direction from the end face of the lock ring to a radially inward direction of the lock ring, When the lock ring is inserted into the lock ring groove in the correct orientation, The gap maintaining jig is engaged with the engagement portion. The engagement portion is located on the open end face side of the socket, and the relief portion is located on the inner end side of the socket, When the lock ring is accommodated in the lock ring accommodation groove in a direction opposite to the normal direction, the relief portion is located on the open end face side of the receiving port and the engagement portion is located on the far end side of the receiving port so that the gap maintaining jig is guided by the relief portion and released from the end face of the lock ring, When the lock ring is in a radially expanded state, the engagement portion and the relief portion are exposed radially inward from the lock ring accommodating groove.

[0014] According to this, when joining one pipe to the other pipe, first, the lock ring is set in the lock ring receiving groove. At this time, when the lock ring is set in the lock ring receiving groove in the correct orientation in the pipe axial direction, the engagement portion is located on the opening end face side of the socket, and the relief portion is located on the inner end side of the socket.

[0015] When the lock ring is subsequently expanded using the expanding tool and the gap maintaining tool is inserted into the divided portion of the lock ring from the open end face of the socket to engage with both engagement portions, the gap maintaining tool engages with the engagement portions because the engagement portions are located closer to the open end face of the socket than the relief portions. This allows the gap maintaining tool to maintain the gap between both end faces of the expanded lock ring.

[0016] The insertion port is then inserted into the receiving port, and after the engagement portion of the insertion port passes around the inner circumference of the lock ring from the open end face side of the receiving port to the rear end side, the gap maintaining jig is removed from the lock ring to reduce the diameter of the lock ring.

[0017] Furthermore, when joining one pipe to the other, if the lock ring is mistakenly set in the lock ring accommodating groove in the opposite direction in the pipe axial direction, the relief portion will be located on the opening end face side of the receiving port and the engagement portion will be located on the inner end side of the receiving port.

[0018] Thereafter, when the lock ring is expanded using the expansion jig and the spacing maintaining jig is inserted into the divided portion of the lock ring from the opening end face of the receiving port to engage with both engagement portions, since the relief portion is located closer to the opening end face of the receiving port than the engagement portions, the spacing maintaining jig does not engage with the engagement portions, but is guided by the relief portion and disengages from the end face of the lock ring radially inward of the lock ring.

[0019] In this way, if the lock ring is mistakenly set in the lock ring accommodating groove in the reversed orientation, even if an attempt is made to engage the spacing maintaining jig with both engagement portions of the lock ring, the spacing maintaining jig will not engage with the engagement portions, but will be guided into the relief portion and detached from the end face of the lock ring, and the spacing maintaining jig will not be able to maintain the spacing between the two end faces of the expanded lock ring.

[0020] This makes it possible to detect incorrect installation of the lock ring before the pipe insertion work of inserting the spigot into the socket is performed, thereby reducing the time required to redo the pipe joining work.

[0021] The pipe joint in the second invention is The lock ring has an inner peripheral surface, an outer peripheral surface, one side surface facing the open end surface of the socket when set in the correct orientation, and another side surface facing the rear end surface of the socket when set in the correct orientation, The relief portion is an inclined surface extending from the end face of the lock ring to the inner peripheral surface of the lock ring, and is inclined in a direction in which the distance between the end faces of the lock ring increases toward the radially inner side. At the same time, the distance between both end faces is inclined in a direction in which it becomes larger as it approaches from one side face to the other side face, and is reduced in the radial direction as it approaches from the other side face to the one side face. It is something.

[0022] According to this, if the lock ring is mistakenly set in the lock ring accommodating groove in the wrong direction, when the lock ring is expanded using the expansion jig, the spacing maintaining jig is guided radially inward of the lock ring by the inclined surface of the escape portion and detaches from the end face of the lock ring.

[0023] In the pipe fitting of the third invention, the relief portion is a curved surface that is curved in an arc shape from the end face of the lock ring to the inner circumferential surface of the lock ring, and is curved in a direction such that the distance between the two end faces of the lock ring increases radially inward.

[0024] According to this, if the lock ring is mistakenly set in the lock ring accommodating groove in the wrong direction, when the lock ring is expanded using the expansion jig, the curved surface of the relief portion guides the spacing maintaining jig radially inward of the lock ring and detaches from the end face of the lock ring.

[0025] The fourth invention is a method for joining pipes using the pipe joint according to any one of claims 1 to 3, Set the lock ring in the lock ring receiving groove in the socket, With the lock ring expanded using the expanding tool, the gap maintaining tool is inserted into the divided portion of the lock ring from the open end face of the socket and engaged with the engaging portions on both end faces. If the gap maintaining jig does not engage with the engagement portion and is guided by the relief portion to come off from the end face of the lock ring, it is determined that the installation direction of the lock ring is reversed in the pipe axial direction, Correct the lock ring to the correct orientation and reinstall it in the lock ring groove. It is something.

[0026] According to this, If the lock ring is mistakenly set in the lock ring accommodating groove with the orientation reversed in the pipe axial direction, the relief portion will be located on the open end face side of the receiving port and the engagement portion will be located on the rear end side of the receiving port, so that the spacing maintaining jig will not engage with the engagement portion and will be guided by the relief portion and will detach from the end face of the lock ring radially inward of the lock ring. As a result, the gap between both end faces of the expanded lock ring cannot be maintained by the gap maintaining jig, and therefore incorrect installation of the lock ring can be noticed before the pipe insertion work of inserting the spigot into the receiving port is performed, thereby reducing the time required to redo the pipe joining work.

[0027] In the pipe joining method according to the fifth aspect of the present invention, if it is determined that the installation direction of the lock ring is reversed in the pipe axial direction, Remove the expansion tool from the lock ring to reduce the diameter of the lock ring, Remove the lock ring from the lock ring receiving groove. Correct the lock ring to the correct orientation and reinsert it into the lock ring groove. With the lock ring expanded using the expanding jig, the gap maintaining jig is inserted into the divided portion of the lock ring from the open end face of the socket and engaged with the engaging portions on both end faces; The diameter expansion jig is removed from the lock ring, and the gap between both end faces of the expanded lock ring is maintained with a gap maintaining jig; The insertion port is inserted into the receiving port, and the engagement body of the insertion port passes around the inner circumference of the lock ring from the opening end face side of the receiving port to the rear end side, and then the spacing maintaining jig is removed from the lock ring to reduce the diameter of the lock ring. Effect of the Invention

[0030] As described above, according to the present invention, if the lock ring is mistakenly set in the wrong direction when joining one pipe to another, it is possible to notice the incorrect installation of the lock ring before the pipe is inserted, thereby reducing the time required to redo the pipe joining work. [Brief description of the drawings]

[0031] [Figure 1] 1 is a cross-sectional view of a pipe joint according to a first embodiment of the present invention. [Diagram 2] 13 is a front view of a divided portion of a lock ring provided in the pipe joint according to the first embodiment. FIG. [Diagram 3] 3 is a view taken along the arrow XX in FIG. 2. [Figure 4] 3 is a view taken along the arrow YY in FIG. 2. [Diagram 5] FIG. 3 is a view taken along the arrow ZZ in FIG. [Figure 6] FIG. [Figure 7] FIG. 4 is an enlarged perspective view of one end surface of the lock ring according to the first embodiment. [Figure 8] FIG. 11 is a diagram showing a diameter expansion jig used when joining pipes of a pipe joint according to the first embodiment. [Figure 9] 11 is a perspective view of a gap maintaining jig used when joining pipes of the pipe joint according to the first embodiment. FIG. [Figure 10] FIG. 4 is a cross-sectional view of the gap maintaining jig of the first embodiment. [Figure 11] FIG. 11 is a diagram for explaining a method of joining pipes in the pipe joint according to the first embodiment, showing the state in which the lock ring is set in the lock ring receiving groove in the correct orientation. [Figure 12] FIG. 11 is a diagram for explaining the pipe joining method according to the embodiment, showing the state in which the lock ring has been expanded using a diameter expansion jig. [Figure 13] This is a diagram explaining the method of joining pipes according to the same embodiment, and shows the state in which the lock ring is expanded in diameter using a diameter expansion jig and a gap maintenance jig is inserted into the divided portion of the lock ring. [Figure 14] This is a diagram explaining the method of joining pipes, showing the state in which the diameter expansion jig is removed from the lock ring and the gap between both end faces of the expanded lock ring is maintained by a gap maintaining jig. [Figure 15] FIG. 11 is a diagram for explaining the pipe joining method according to the embodiment, showing the state in which the gap maintaining jig is removed from the lock ring and the lock ring is reduced in diameter. [Figure 16]FIG. 11 is a diagram for explaining the method of joining pipes according to the first embodiment, showing the state in which the lock ring is set in the lock ring receiving groove in the reverse orientation. [Figure 17] FIG. 11 is a diagram for explaining the pipe joining method according to the embodiment, showing the state in which the lock ring has been expanded using a diameter expansion jig. [Figure 18] This is a diagram explaining the method of joining pipes, and shows how, when the lock ring is expanded using the expansion jig and a spacing maintaining jig is inserted into the divided portion of the lock ring, the spacing maintaining jig is guided into the relief portion and detached from the end face of the lock ring. [Figure 19] 13 is a rear view of a divided portion of a lock ring provided in a pipe joint according to a second embodiment of the present invention. FIG. [Figure 20] FIG. 1 is a cross-sectional view of a conventional pipe joint. [Figure 21] FIG. 11 is an enlarged cross-sectional view of the lock ring of the pipe joint when it is set in the lock ring receiving groove in the correct orientation. [Figure 22] FIG. 11 is an enlarged cross-sectional view of the lock ring when it is set in the lock ring receiving groove in the reverse direction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0033] (First embodiment) In the first embodiment, as shown in FIG. 1, reference numeral 1 denotes a pipe joint in which an insertion port 3 of one pipe 2 is inserted into a receiving port 5 of the other pipe 4 to join pipes 2 and 4 together.

[0034] A lock ring accommodating groove 7 is formed around the entire inner circumference of the socket 5. A lock ring 8 is accommodated in the lock ring accommodating groove 7. An insertion port protrusion 10 (an example of an engagement body) is formed around the entire outer circumference of the tip of the insertion port 3. The pipe fitting 1 has an anti-detachment function that prevents the insertion port 3 from being detached from the socket 5 by the insertion port protrusion 10 engaging with the lock ring 8 from the rear side of the socket 5 in the removal direction 12 of the insertion port 3. A socket protrusion 16 protruding inward in the pipe diameter direction 15 from the inner periphery of the socket 5 faces the lock ring receiving groove 7 on the side of the opening end face 14 of the socket 5 . The gap between the outer periphery of the insertion port 3 and the inner periphery of the receiving port 5 is sealed by an annular sealing member 17 made of an elastic material such as rubber. A pressure ring 18 that presses the seal member 17 toward the back of the socket 5 abuts against the open end face 14 of the socket 5 and is connected to a flange portion 21 of the socket 5 by multiple sets of T-bolts 19 and nuts 20.

[0035] In addition, a resin backup ring 23 is provided between the inner circumference of the socket protrusion 16 and the outer circumference of the insertion port 3. The backup ring 23 is a ring with a single split structure that is split at one point, and is disposed adjacent to the lock ring 8.

[0036] The insertion port 3 passes through the inner periphery of the pressure ring 18 , the seal member 17 , the backup ring 23 and the lock ring 8 .

[0037] 2 to 7, lock ring 8 is a ring of a single split structure having a split portion 24 split at one location, and has an inner circumferential surface 27, an outer circumferential surface 28, one side surface 29 facing open end face 14 of socket 5 when set in the correct orientation, another side surface 30 facing rear end face 26 of socket 5 when set in the correct orientation, and a pair of end faces 32, 33 opposing each other in the circumferential direction 31. One side surface 29 of lock ring 8 has a curved surface that is curved in an arc shape.

[0038] Lock ring 8 is a resilient metal ring that is expandable and contractable in the radial direction, and the diameter of lock ring 8 can be expanded using diameter expansion jig 101 (see FIG. 8). Also, gap 42 between both end faces 32, 33 of lock ring 8 can be maintained using gap maintaining jig 123 (see FIG. 9 and FIG. 10).

[0039] As shown in FIGS. 3 and 4, both end faces 32, 33 of the lock ring 8 have engagement portions 32a, 33a with which the contact bodies 121, 122 of the gap maintaining jig 123 can engage.

[0040] In addition, one end face 32 of the lock ring 8 has an escape portion 45 that allows the contact bodies 121, 122 of the gap maintaining jig 123 to escape in a removal direction 44 (see Figure 18) from the end face 32 of the lock ring 8 toward the radial inside of the lock ring 8.

[0041] As shown in Figure 6, the relief portion 45 is an inclined surface extending from the end face 32 of the lock ring 8 to the inner circumferential surface 27, and when viewed from the other side surface 30 of the lock ring 8, it is inclined in a direction such that the gap 42 between both end faces 32, 33 increases radially inward, and also in a direction such that the gap 42 between both end faces 32, 33 increases as it approaches from the one side surface 29 to the other side surface 30.

[0042] As shown in FIG. 3, the relief portion 45 is gradually reduced in the radial direction 47 from the other side surface 30 toward the one side surface 29, and is formed in the shape of a right-angled triangle when viewed in the circumferential direction 31.

[0043] As shown in Fig. 11, when the lock ring 8 is accommodated in the lock ring accommodating groove 7 in the correct orientation, the engagement portions 32a, 33a are located on the opening end face 14 side of the socket 5, and the relief portion 45 is located on the rear end face 26 side of the socket 5. Also, as shown in Fig. 16, when the lock ring 8 is accommodated in the lock ring accommodating groove 7 in the reverse orientation, the relief portion 45 is located on the opening end face 14 side of the socket 5, and the engagement portions 32a, 33a are located on the rear end face 26 side of the socket 5.

[0044] 12 and 17, when lock ring 8 is in an expanded diameter state, engagement portions 32a, 33a and relief portion 45 are exposed radially inward from lock ring accommodating groove 7. At this time, outer end portion 45a of relief portion 45 in radial direction 47 (see FIGS. 3 and 7) enters lock ring accommodating groove 7.

[0045] Next, the structure of the diameter expansion jig 101 will be described.

[0046] 8, the diameter expansion jig 101 is a scissors-shaped jig having a pair of legs 102 that can be opened and closed, a screw rod 103 screwed into both legs 102, and a handle 104. By rotating the handle 104, the screw feed mechanism of the screw rod 103 opens and closes both legs 102, and the distance between the tips of both legs 102 is expanded and contracted.

[0047] Next, the structure of the gap maintaining jig 123 will be described.

[0048] As shown in Figures 9 and 10, the gap maintaining jig 123 has a pair of contact bodies 121, 122 that are inserted into the divided portion 24 of the lock ring 8 and can contact the engagement portions 32a, 33a of the lock ring 8, and a gap adjustment means 125 that connects the two contact bodies 121, 122 and can adjust the gap 124 between the two contact bodies 121, 122 along the circumferential direction 31 of the lock ring 8.

[0049] The gap adjustment means 125 has a threaded portion 126 provided across the first contact body 121 and the second contact body 122, and a butterfly bolt 127 attached to the threaded portion 126 to rotate the threaded portion 126. One end side of the threaded portion 126 is formed with a straight portion 128 that is smaller in diameter than the root portion of the threaded portion 126 and has no male thread formed on its outer periphery.

[0050] The first contact body 121 has a plate-shaped insertion portion 121a formed to a length that reaches the outside of the socket 5, a handle portion 121b, and a socket portion 121c through which the straight portion 128 of the screw portion 126 is inserted.

[0051] The screw portion 126 rotates freely relative to the socket portion 121c, and the socket portion 121c is fixed so as not to move relative to the screw portion 126 in the axial direction. Furthermore, a rod-shaped anti-rotation member 129 for preventing the first contact body 121 and the second contact body 122 from rotating relative to each other is attached to the upper portion of the socket portion 121c from the first contact body 121 to the second contact body 122.

[0052] The second contact body 122 has a plate-shaped insertion portion 122a formed to a length that reaches the outside of the receiving port 5, a handle portion 122b, and a socket portion 122c having a female thread portion 122d formed on its inner surface so as to be able to engage with the screw portion 126. The other end of the screw portion 126 is screwed into the socket portion 122c, and by rotating the screw portion 126, the screw feed mechanism moves the second contact body 122 closer to or farther from the first contact body 121 in the axial direction of the screw portion 126, making it possible to adjust the distance 124 between the first contact body 121 and the second contact body 122.

[0053] A method for joining the pipes 2, 4 in the pipe joint 1 will now be described. First, the backup ring 23, the seal member 17, and the press ring 18 are fitted onto the outside of the insertion port 3 in advance. Then, as shown in Fig. 11, the lock ring 8 is set (housed) in the lock ring housing groove 7. At this time, when the lock ring 8 is set in the lock ring housing groove 7 with its orientation in the normal direction in the pipe axis direction, the engagement portions 32a, 33a are located on the opening end face 14 side of the socket 5, and the relief portion 45 is located on the rear end face 26 side of the socket 5.

[0054] 12, the diameter of the lock ring 8 is expanded using a diameter expansion jig 101. At this time, the tips of both legs 102 of the diameter expansion jig 101 are inserted into the divided portion 24 of the lock ring 8, the tip of one leg 102 is inserted into the lock ring accommodating groove 7 to engage with one end face 32 of the lock ring 8, and the tip of the other leg 102 is inserted into the lock ring accommodating groove 7 to engage with the other end face 33 of the lock ring 8, and the handle 104 is rotated to open both legs 102. As a result, the gap 42 between both end faces 32, 33 of the lock ring 8 is expanded, and the lock ring 8 is expanded in diameter.

[0055] Furthermore, when the tips of both legs 102 of the expansion jig 101 are engaged with the end faces 32, 33 of the lock ring 8 as described above, the tips of both legs 102 are shifted toward the rear end face 26 of the receiving port 5 rather than the two engagement portions 32a, 33a of the lock ring 8. In this state, both insertion portions 121a, 122a of the gap maintaining jig 123 are inserted into the dividing portion 24 of the lock ring 8 from the opening end face 14 of the receiving port 5, and the wing bolt 127 is turned to expand the gap 124 between the first contact body 121 and the second contact body 122.

[0056] As a result, as shown in Figure 13, the insertion portion 121a of the first contact body 121 of the gap maintaining jig 123 engages with the engagement portion 32a on one end face 32 of the lock ring 8, and the insertion portion 122a of the second contact body 122 engages with the engagement portion 33a on the other end face 33 of the lock ring 8.

[0057] 14, by removing diameter expansion jig 101 from lock ring 8, gap 42 between both end faces 32, 33 of the expanded lock ring 8 is maintained by gap maintaining jig 123. As a result, even if diameter expansion jig 101 is removed from lock ring 8, lock ring 8 continues to be maintained in the expanded diameter state.

[0058] In this state, the insertion port 3 is inserted into the receiving port 5, and after the insertion port protrusion 10 of the insertion port 3 passes around the inner circumference of the lock ring 8 from the opening end face 14 of the receiving port 5 to the rear end face 26, the spacing maintaining jig 123 is removed from the lock ring 8.

[0059] As a result, as shown in Figure 15, the insertion portions 121a, 122a of the gap maintaining jig 123 disengage from the engagement portions 32a, 33a of the lock ring 8, the gap 42 between both end faces 32, 33 of the lock ring 8 is reduced, and the lock ring 8 is reduced in diameter and hugs the outer periphery of the insertion port 3.

[0060] 1, the backup ring 23 is moved in the pipe axial direction and inserted between the inner periphery of the socket protrusion 16 and the outer periphery of the insertion port 3, the seal member 17 is moved in the pipe axial direction and inserted between the inner periphery of the socket 5 and the outer periphery of the insertion port 3, and the press ring 18 is connected to the flange portion 21 of the socket 5 using multiple sets of T-bolts 19 and nuts 20 and abutted against the open end face 14. This joins the pipes 2, 4 together.

[0061] Furthermore, when setting (accommodating) the lock ring 8 in the lock ring accommodating groove 7, if the lock ring 8 is mistakenly set in the lock ring accommodating groove 7 in the opposite direction in the pipe axis direction as shown in Figure 16, the escape portion 45 will be located on the opening end face 14 side of the receiving port 5, and the engagement portions 32a, 33a will be located on the rear end face 26 side of the receiving port 5.

[0062] 17, the tips of both legs 102 of diameter expansion jig 101 are inserted into divided portion 24 of lock ring 8, the tip of one leg 102 is inserted into lock ring receiving groove 7 to engage with one end face 32 of lock ring 8, and the tip of the other leg 102 is inserted into lock ring receiving groove 7 to engage with the other end face 33 of lock ring 8, and handle 104 is rotated to open both legs 102. This enlarges space 42 between both end faces 32, 33 of lock ring 8, and the lock ring 8 is expanded in diameter.

[0063] Furthermore, when the tips of both legs 102 of the expansion jig 101 are engaged with the end faces 32, 33 of the lock ring 8 as described above, the tips of both legs 102 are shifted from the relief portion 45 of the lock ring 8 toward the rear end face 26 of the receiving port 5. In this state, as shown in Figure 18, both insertion portions 121a, 122a of the gap maintaining jig 123 are inserted from the opening end face 14 of the receiving port 5 into the dividing portion 24 of the lock ring 8, and the wing bolt 127 is turned to expand the gap 124 between the first contact body 121 and the second contact body 122.

[0064] Even if one attempts to engage the insertion portions 121a, 122a of the gap maintaining jig 123 with the engagement portions 32a, 33a of the lock ring 8 in this manner, the relief portion 45 is located on the opening end face 14 side of the receiving port 5, so the insertion portion 122a of the second contact body 122 does not engage with one of the engagement portions 32a. Instead, as shown by the virtual line in Figure 18, it is guided by the inclined relief portion 45 and slides over the relief portion 45 in the removal direction 44, and removes from one end face 32 radially inward of the lock ring 8.

[0065] As a result, the gap 42 between the end faces 32, 33 of the lock ring 8, which has been expanded by the expanding jig 101, cannot be maintained by the gap maintaining jig 123, and therefore, incorrect installation of the lock ring 8 can be noticed before the pipe insertion work of inserting the insertion port 3 into the receiving port 5 is performed, thereby shortening the time required to redo the joining work of the pipes 2, 4.

[0066] Furthermore, if the joining work of the pipes 2, 4 needs to be redone, first the diameter expansion jig 101 is removed from the lock ring 8 to reduce the diameter of the lock ring 8, the lock ring 8 is removed from the lock ring accommodating groove 7, and the lock ring 8 is then corrected to the correct orientation as shown in Figure 11 and set back in the lock ring accommodating groove 7. Thereafter, similarly, as shown in Figs. 12 to 15, the diameter of lock ring 8 is expanded using diameter expansion jig 101, and lock ring 8 is maintained in the expanded diameter state using gap maintaining jig 123. (Second embodiment) In the first embodiment described above, as shown in FIG. 6, the relief portion 45 is an inclined surface, but is not limited to an inclined surface. For example, as a second embodiment, as shown in FIG. 19, the relief portion 45 is a curved surface that is curved in an arc shape from the end face 32 of the lock ring 8 to the inner circumferential surface 27, and is curved in a direction such that the gap 42 between the end faces 32, 33 increases radially inward.

[0067] According to this, if the lock ring 8 is mistakenly set in the lock ring accommodating groove 7 with the orientation reversed, when the lock ring 8 is expanded using the diameter expansion jig 101, the insertion portion 121a of the first contact body 121 of the spacing maintaining jig 123 will not engage with one of the engagement portions 32a, but will be guided by the curved relief portion 45 and slide over the relief portion 45 in the removal direction 44, and will remove from one end face 32 radially inward of the lock ring 8.

[0068] In the above-described first and second embodiments, as shown in Figs. 6 and 19, the relief portion 45 is formed on one end face 32 of the lock ring 8, but it may be formed on both end faces 32, 33. [Explanation of symbols]

[0069] 1 Pipe fittings 2 One tube 3 Insertion port 4 The other tube 5 socket 7 Lock ring receiving groove 8 Lock Ring 10 Insertion port protrusion (engagement body) 12 Removal direction 14 Opening end face 24 Divided part 26 Back end surface 27 Inner surface 31 Circumferential direction 32,33 End face 32a, 33a Engagement part 42 interval 44 Exit direction 45 Relief 101 Diameter expansion tool 123 Spacing maintenance jig

Claims

1. The spigot of one tube is inserted into the socket of the other tube, A lock ring receiving groove is formed on the inner circumference of the socket. The lock ring is accommodated in the lock ring accommodating groove, An engagement body is formed on the outer periphery of the insertion port, A pipe fitting capable of preventing the insertion port from being removed from the socket by an engagement body engaging with a lock ring from a back side of the socket in a removal direction of the insertion port, The lock ring is a ring with a single split structure having a split portion at one point, Both end faces of the lock ring in the circumferential direction have engagement portions with which a gap maintaining jig can be engaged that maintains the gap between the both end faces of the lock ring expanded by the diameter expanding jig, At least one end face of the lock ring has a relief portion that allows the gap maintaining jig to escape in a detachment direction from the end face of the lock ring to a radially inward direction of the lock ring, When the lock ring is accommodated in the lock ring accommodation groove in the correct orientation, the engagement portion is located on the open end face side of the socket so that the gap maintaining jig engages with the engagement portion, and the relief portion is located on the back end side of the socket, When the lock ring is accommodated in the lock ring accommodation groove in a direction opposite to the normal direction, the relief portion is located on the open end face side of the receiving port and the engagement portion is located on the far end side of the receiving port so that the gap maintaining jig is guided by the relief portion and released from the end face of the lock ring, A pipe joint characterized in that, when the lock ring is in a diameter-expanded state, the engagement portion and the relief portion are exposed radially inward from the lock ring accommodating groove.

2. The lock ring has an inner peripheral surface, an outer peripheral surface, one side surface facing the open end face of the receiving port when set in the correct orientation, and another side surface facing the rear end face of the receiving port when set in the correct orientation, The pipe fitting according to claim 1, characterized in that the relief portion is an inclined surface extending from an end face of the lock ring to the inner peripheral surface of the lock ring, inclined in a direction in which the gap between both end faces of the lock ring increases radially inward, inclined in a direction in which the gap between both end faces increases as the lock ring approaches from one side surface to the other side surface, and decreases radially as the lock ring approaches from the other side surface to the one side surface.

3. 2. A pipe fitting according to claim 1, characterized in that the relief portion is a curved surface that is curved in an arc shape from the end face of the lock ring to the inner circumferential surface of the lock ring, and is curved in a direction such that the gap between the two end faces of the lock ring increases radially inward.

4. A method for joining pipes in the pipe joint according to any one of claims 1 to 3, comprising the steps of: Set the lock ring in the lock ring receiving groove in the socket, When the lock ring is expanded using the expansion jig and the gap maintaining jig is inserted into the divided portion of the lock ring from the open end face of the receiving port to engage with the engagement portions on both end faces, if the gap maintaining jig does not engage with the engagement portions and is guided into the relief portion and disengaged from the end face of the lock ring, it is determined that the installation direction of the lock ring is reversed in the pipe axial direction, A pipe joining method characterized in that the lock ring is corrected to the correct orientation and reset in the lock ring receiving groove.

5. If it is determined that the installation direction of the lock ring is reversed in the pipe axial direction, Remove the expansion tool from the lock ring to reduce the diameter of the lock ring, Remove the lock ring from the lock ring receiving groove. Correct the lock ring to the correct orientation and reinsert it into the lock ring groove. With the lock ring expanded using the expanding jig, the gap maintaining jig is inserted into the divided portion of the lock ring from the open end face of the socket and engaged with the engaging portions on both end faces; The diameter expansion jig is removed from the lock ring, and the gap between both end faces of the expanded lock ring is maintained with a gap maintaining jig; A method for joining pipes as described in claim 4, characterized in that the insertion port is inserted into the receiving port, and after the engagement body of the insertion port passes around the inner circumference of the lock ring from the opening end face side of the receiving port to the rear end side, the gap maintaining jig is removed from the lock ring and the lock ring is reduced in diameter.

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