JP7629845B2 - Pipe joint and pipe joining method - Google Patents

Description

The present invention relates to a pipe fitting and a method for joining pipes, in which the insertion port of one pipe is inserted into the receiving port of the other pipe and has a function to prevent disengagement.

Conventionally, as shown in Figures 20 and 21, this type of pipe fitting has a function of preventing the insertion port 202 from being removed from the socket 204 by, for example, inserting the insertion port 202 of one pipe 201 into the socket 204 of the other pipe 203, forming a lock ring accommodation groove 205 on the inner circumference of the socket 204, accommodating a lock ring 206 in the lock ring accommodation groove 205, and forming an insertion port protrusion 207 on the outer circumference of the tip of the insertion port 202, which engages with the lock ring 206 from the back side of the socket 204 in the removal direction 208 of the insertion port 202.

The gap between the inner circumference of the receiving port 204 and the outer circumference of the insertion port 202 is sealed with a rubber ring 209, which is pressed toward the back of the receiving port 204 by a pressure ring 210.

The side of the lock ring receiving groove 205 on the receiving opening side is formed as a tapered surface 211. The lock ring 206 is a ring with a single split structure having a split portion (not shown) where one part is split, which allows the diameter of the lock ring 206 to be expanded or contracted. The side of the lock ring 206 on the receiving opening side is formed as a tapered surface 213.

When joining one pipe 201 and the other pipe 203 in the pipe joint 200 as described above, the lock ring 206 is set in the lock ring receiving groove 205 in the receiving port 204, and the lock ring 206 is expanded using an expansion tool (not shown). A spacing maintenance tool (not shown) is set at the divided portion of the lock ring 206 in the expanded state, and the expansion tool is removed from the lock ring 206, and the spacing between both end faces at the divided portion of the lock ring 206 in the expanded state is maintained by the spacing maintenance tool.

As shown in FIG. 21, when the orientation of the lock ring 206 is set correctly, the lock ring 206 is maintained in an expanded state and is stored to the back of the lock ring storage groove 205. After that, by inserting the insertion port 202 into the receiving port 204, the insertion port protrusion 207 passes along the inner circumference of the lock ring 206 from the open end face side of the receiving port 204 to the back end side.

Also, as shown in FIG. 22, if the lock ring 206 is mistakenly set in the opposite direction, the lock ring 206 will be maintained in an expanded state, but the outer periphery 206a of the lock ring 206 will come into contact with the tapered surface 211 of the lock ring accommodating groove 205, so the lock ring 206 cannot be accommodated all the way into the lock ring accommodating groove 205, and the insertion port protrusion 207 will get caught on the lock ring 206 that protrudes from the lock ring accommodating groove 205, making it impossible to insert the insertion port 202 into the receiving port 204.

This makes it possible to prevent incorrect joining when joining one tube 201 to the other tube 203.

The above-mentioned pipe joint is described, for example, in Patent Document 1 below, and the diameter expansion jig and the gap maintenance jig are described, for example, in Patent Document 2 below.

JP2004-232679 Patent No. 4446805

However, in the above conventional type, as shown in Figure 22, if the lock ring 206 is set in the wrong direction when joining the pipes 201 and 203, it is not possible to notice that the lock ring 206 is attached incorrectly until the pipe insertion work of inserting the insertion port 202 into the receiving port 204 is performed, and this creates the problem that it takes time to redo the joining work of the pipes 201 and 203.

The present invention aims to provide a pipe fitting and a pipe joining method that, if the lock ring is mistakenly set in the wrong direction, makes it possible to detect the incorrect installation of the lock ring before inserting the pipe.

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 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,
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.

According to this, when joining one pipe to the other pipe, the lock ring is first set in the lock ring receiving groove. At this time, if 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 open end face side of the receiving port, and the relief portion is located on the inner end side of the receiving port.

After that, when the lock ring is expanded using the expansion tool, 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, as the engagement portion is located closer to the open end face of the socket than the relief portion, the gap maintaining tool engages with the engagement portion. This allows the gap maintaining tool to maintain the gap between both end faces of the expanded lock ring.

Then, insert the insertion port into the receiving port, and after the engagement portion of the insertion port passes around the inner circumference of the lock ring from the opening end face side to the inner end side of the receiving port, remove the gap maintaining jig from the lock ring to reduce the diameter of the lock ring.

When joining one pipe to the other, if the lock ring is mistakenly placed in the lock ring groove in the opposite direction along the pipe axis, the relief portion will be located on the open end face side of the socket, and the engagement portion will be located on the inner end side of the socket.

After that, when the lock ring is expanded using the expansion tool and the gap maintenance tool is inserted from the open end face of the receiving port into the divided portion of the lock ring to engage with both engagement parts, the relief part is located closer to the open end face of the receiving port than the engagement part, so the gap maintenance tool does not engage with the engagement part, but is guided by the relief part and disengages from the end face of the lock ring radially inward.

In this way, if the lock ring is mistakenly set in the lock ring receiving groove in the wrong direction, 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 faces of the lock ring, and the spacing maintaining jig will not be able to maintain the spacing between both end faces of the expanded lock ring.

This allows incorrect installation of the lock ring to be noticed before the pipe insertion work of inserting the plug into the socket is performed, reducing the time required to redo the pipe joining work.

In the pipe fitting of the second invention, the lock ring has an inner circumferential surface, an outer circumferential surface, one side surface facing the open end face of the socket when set in the correct orientation, and another side surface facing the rear end face 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 the direction in which the spacing between both end faces of the lock ring increases radially inward , and is inclined in the direction in which the spacing between both end faces increases as it approaches from one side to the other side, and is also inclined in the radial direction as it approaches from the other side to the one side .

According to this, if the lock ring is mistakenly set in the lock ring receiving groove in the wrong direction, when the lock ring is expanded using the expansion tool, the gap maintaining tool is guided radially inward by the inclined surface of the relief portion and disengages from the end face of the lock ring.

The pipe fitting in this third invention has a relief portion that is a curved surface that is curved in an arc shape from the end face of the lock ring to the inner peripheral surface of the lock ring, and is curved in a direction such that the distance between both end faces of the lock ring increases as it moves radially inward.

According to this, if the lock ring is mistakenly set in the lock ring receiving groove in the wrong direction, when the lock ring is expanded using the expansion jig, the curved surface of the relief portion guides the gap maintaining jig radially inward of the lock ring and causes it to detach from the end face of the lock ring.

The fourth invention is a method for joining pipes in 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,
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 portions and disengaged from the end faces of the lock ring, it is determined that the installation direction of the lock ring is reversed in the pipe axial direction,
The lock ring is then adjusted to the correct orientation and reset into the lock ring receiving groove .

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 opening 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 to disengage 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.

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.

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. This reduces the time required to redo the pipe joining work.

1 is a cross-sectional view of a pipe joint according to a first embodiment of the present invention. 13 is a front view of a divided portion of a lock ring provided in the pipe joint according to the first embodiment. FIG. 3 is a view taken along the line XX in FIG. 2. 3 is a view taken along the line YY in FIG. 2. 3 is a view taken along the line Z-Z in FIG. 2. FIG. FIG. 4 is an enlarged perspective view of one end surface of the lock ring according to the first embodiment. FIG. 11 is a diagram showing a diameter expansion jig used when joining pipes of a pipe joint according to the first embodiment. 11 is a perspective view of a gap maintaining jig used when joining pipes of the pipe joint according to the first embodiment. FIG. FIG. 4 is a cross-sectional view of the gap maintaining jig of the first embodiment. 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. 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. 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. 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. 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. 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. 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. This is a diagram explaining the method of joining pipes, and shows how, when the lock ring is expanded using the expansion tool 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. FIG. 11 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. 1 is a cross-sectional view of a conventional pipe joint. 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. 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.

The following describes an embodiment of the present invention with reference to the drawings.

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

A lock ring receiving groove 7 is formed around the entire inner circumference of the socket 5. A lock ring 8 is received in the lock ring receiving groove 7. A socket protrusion 10 (an example of an engagement body) is formed around the entire outer circumference of the tip of the socket 3.
The pipe fitting 1 has an anti-detachment function that prevents the insertion port 3 from being detached from the receiving port 5 by the insertion port protrusion 10 engaging with the lock ring 8 from the rear side of the receiving port 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 accommodating 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.

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 split structure that is split at one point, and is located adjacent to the lock ring 8.

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

As shown in Figures 2 to 7, the lock ring 8 is a ring with 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 that faces the open end surface 14 of the socket 5 when set in the correct orientation, the other side surface 30 that faces the inner end surface 26 of the socket 5 when set in the correct orientation, and a pair of end surfaces 32, 33 that face each other in the circumferential direction 31. The one side surface 29 of the lock ring 8 has a curved surface that is curved in an arc shape.

The lock ring 8 is an elastic metal ring that can be expanded or contracted in the radial direction, and the diameter of the lock ring 8 can be expanded using a diameter expansion jig 101 (see FIG. 8). The gap 42 between both end faces 32, 33 of the lock ring 8 can be maintained using a gap maintenance jig 123 (see FIG. 9 and FIG. 10).

As shown in Figures 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 spacing maintaining jig 123 can engage.

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 detachment direction 44 (see Figure 18) from the end face 32 of the lock ring 8 toward the radial inside of the lock ring 8.

As shown in FIG. 6, the relief portion 45 is an inclined surface extending from the end face 32 of the lock ring 8 to the inner peripheral surface 27, and when viewed from the other side surface 30 of the lock ring 8, the clearance 42 between the end faces 32, 33 is inclined in a direction in which it increases radially inward, and the clearance 42 between the end faces 32, 33 is inclined in a direction in which it increases radially inward as it approaches from the one side surface 29 to the other side surface 30.

As shown in FIG. 3, the relief portion 45 is reduced in the radial direction 47 as it approaches the one side 29 from the other side 30, and is formed in the shape of a right triangle when viewed from the circumferential direction 31.

As shown in FIG. 11, when the lock ring 8 is accommodated in the lock ring accommodation groove 7 in the correct orientation, the engagement portions 32a and 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 accommodation 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 and 33a are located on the rear end face 26 side of the socket 5.

As shown in Figures 12 and 17, when the lock ring 8 is in an expanded state, the engagement portions 32a, 33a and the relief portion 45 are exposed radially inward from the lock ring housing groove 7. At this time, the outer end portion 45a of the relief portion 45 in the radial direction 47 (see Figures 3 and 7) enters the lock ring housing groove 7.

Next, the structure of the expansion jig 101 will be described.

As shown in FIG. 8, the diameter expansion jig 101 is a scissors-shaped jig that has a pair of legs 102 that can be opened and closed, a screw rod 103 that is 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, expanding and reducing the distance between the tips of both legs 102.

Next, the structure of the spacing maintaining jig 123 will be explained.

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.

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. At one end of the threaded portion 126, a straight portion 128 is formed that is smaller in diameter than the valley portion of the threaded portion 126 and has no male thread formed on its outer periphery.

The first contact body 121 has a plate-shaped insertion portion 121a that is long enough to reach the outside of the socket 5, a handle portion 121b, and a socket portion 121c into which the straight portion 128 of the threaded portion 126 is inserted.

The threaded portion 126 rotates freely relative to the socket portion 121c, and the socket portion 121c is fixed to the threaded portion 126 so that it cannot move relative to the axial direction. Furthermore, a rod-shaped anti-rotation member 129 is attached to the upper portion of the socket portion 121c from the first contact body 121 to the second contact body 122 to prevent the first contact body 121 and the second contact body 122 from rotating relative to each other.

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.

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. 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 tube 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.

Next, as shown in FIG. 12, the lock ring 8 is expanded using an expansion tool 101. At this time, the tips of both legs 102 of the expansion tool 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 housing 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 housing 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.

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.

As a result, as shown in FIG. 13, the insertion portion 121a of the first contact body 121 of the spacing maintaining jig 123 engages with the engagement portion 32a of 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 of the other end face 33 of the lock ring 8.

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

In this state, insert the insertion port 3 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, remove the spacing jig 123 from the lock ring 8.

As a result, as shown in FIG. 15, the insertion portions 121a, 122a of the gap maintaining jig 123 are disengaged 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 clings to the outer periphery of the insertion port 3.

Then, as shown in FIG. 1, the backup ring 23 is moved in the pipe axial direction and inserted between the inner circumference of the socket protrusion 16 and the outer circumference of the insertion port 3, the seal member 17 is moved in the pipe axial direction and inserted between the inner circumference of the socket 5 and the outer circumference 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 and 4 together.

When the lock ring 8 is set (housed) in the lock ring housing groove 7, if the lock ring 8 is mistakenly set in the lock ring housing groove 7 in the opposite direction in the tube axis direction as shown in Figure 16, the relief portion 45 will be located on the opening end surface 14 side of the receiving port 5, and the engagement portions 32a, 33a will be located on the rear end surface 26 side of the receiving port 5.

In this case as well, as shown in FIG. 17, 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 housing 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 housing 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. This expands the gap 42 between both end faces 32, 33 of the lock ring 8, expanding the diameter of the lock ring 8.

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 butterfly bolt 127 is turned to expand the gap 124 between the first contact body 121 and the second contact body 122.

Even if the insertion portions 121a, 122a of the spacing jig 123 are engaged with the engagement portions 32a, 33a of the lock ring 8 in this way, the relief portion 45 is located on the side of the opening end face 14 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, and instead slides along the inclined relief portion 45 in the removal direction 44, as shown by the imaginary line in Figure 18, and releases from one end face 32 radially inward of the lock ring 8.

As a result, the gap 42 between the two 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. Therefore, the 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, and the time required to redo the joining work of the pipes 2, 4 can be shortened.

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 the lock ring 8 is expanded using the diameter expansion jig 101, and the lock ring 8 is maintained in the expanded diameter state using the 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.

Accordingly, if the lock ring 8 is mistakenly set in the lock ring receiving groove 7 in the reversed orientation, when the lock ring 8 is expanded using the expansion jig 101, the insertion portion 121a of the first contact body 121 of the spacing maintaining jig 123 does not engage with one of the engagement portions 32a, but is guided by the curved relief portion 45 and slides on the relief portion 45 in the removal direction 44, and is removed from one end face 32 radially inward of the lock ring 8.

In the first and second embodiments described above, as shown in Figures 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.

1 Pipe joint 2 One pipe 3 Insertion port 4 Other pipe 5 Socket 7 Lock ring receiving groove 8 Lock ring 10 Insertion port protrusion (engagement body)
12 Removal direction 14 Open end surface 24 Separation portion 26 Back end surface 27 Inner circumferential surface 31 Circumferential direction 32, 33 End surfaces 32a, 33a Engagement portion 42 Spacing 44 Removal direction 45 Relief portion 101 Diameter expansion jig 123 Spacing maintenance jig

Claims (5)

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. 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 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. The 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 peripheral surface of the lock ring, and is curved in a direction in which the distance between both end faces of the lock ring increases as it moves radially inward. 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 portions and disengaged from the end faces 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 . If it is determined that the lock ring is installed in the wrong direction in the tube axis 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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