Pipe joint detachment prevention device and pipe joint detachment prevention structure

Abstract

The present invention provides a pipe joint detachment prevention device and detachment prevention structure that can perform a detachment prevention function regardless of the presence or absence of a stepped portion or the difference in height of the receiving portion. [Solution] The pipe joint 10, formed by inserting the spigot 2 of a second pipe P2 into the socket 1 of a first pipe P1, is equipped with a socket fitting 5 fitted to the first pipe P1 and a retaining fitting 6 fitted to the second pipe P2. The socket fitting 5 has a first inner surface 51 that engages in the pipe axis direction with the outer surface of an enlarged diameter portion 12 of the first pipe P1, which gradually increases in outer diameter from the body portion 11 toward the socket portion 1. The retaining fitting 6 has a locking member 61 that can be locked to the outer surface of the second pipe P2. The socket fitting 5 and the retaining fitting 6 are engaged or connected to each other so that relative movement between the socket fitting 5 and the retaining fitting 6 in the pipe axis direction is restricted when a detachment force is applied that separates the spigot 2 from the socket portion 1.

Description

[Technical Field]

[0001] The present disclosure relates to a detachment prevention device and a detachment prevention structure for pipe joints. [Background Art]

[0002] Patent Document 1 describes a device for preventing detachment of a pipe joint. According to the device, a detachment prevention function is exerted when a detachment force acting to separate a socket part and a spigot part inserted into the socket is applied. The device includes a mechanism that engages with a step provided on the socket part of a pipe, and it is assumed that the pipe joint to which the device is attached is of a type in which the socket part has a step, such as T-type, NS-type, and GX-type pipe joints. A similar device is also described in FIG. 10 of Patent Document 2 and Patent Document 3. [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2009-85376 [Patent Document 2] Japanese Unexamined Patent Application Publication No. 2010-261480 [Patent Document 3] Japanese Unexamined Patent Application Publication No. 2018-71762 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] Incidentally, some types of pipe joints have a socket part that does not have a step. In such cases, the above-described device cannot be attached, and thus the detachment prevention function cannot be exerted. Further, even if the socket part is of a type having a step, when the height difference (outer diameter difference) of the step is so small that it interferes with engagement, it is difficult to properly attach the device, and thus the detachment prevention function cannot be exerted in this case either.

[0005] This disclosure has been made in view of the above circumstances, and its purpose is to provide a pipe joint detachment prevention device and detachment prevention structure that can perform a detachment prevention function regardless of the presence or absence of a stepped portion or the difference in height of the receiving portion. [Means for solving the problem]

[0006] The pipe joint detachment prevention device of the present disclosure is a pipe joint detachment prevention device comprising a socket portion of a first pipe into a socket portion of a second pipe, and includes a socket fitting fitted externally on the first pipe and a retaining fitting fitted externally on the second pipe. The socket fitting has a first inner surface that engages in the pipe axis direction with the outer surface of an enlarged diameter portion of the first pipe, which gradually increases in outer diameter from the body portion toward the socket portion. The retaining fitting has a locking member that can be locked to the outer surface of the second pipe. The socket fitting and the retaining fitting are engaged or connected to each other such that relative movement between the socket fitting and the retaining fitting in the pipe axis direction is restricted when a detachment force is applied that detaches the socket portion from the socket portion.

[0007] The pipe joint detachment prevention structure of the present disclosure is a pipe joint formed by inserting the spigot portion of the second pipe into the socket portion of the first pipe, and the above-mentioned detachment prevention device is attached to the pipe joint. [Brief explanation of the drawing]

[0008] [Figure 1] Perspective view showing an example of a pipe joint detachment prevention structure related to this disclosure. [Figure 2] Side view of the detachment prevention structure shown in Figure 1. [Figure 3] Front view of the detachment prevention structure shown in Figure 1. [Figure 4] Cross-sectional view taken along arrow AA in Figure 3. [Figure 5] Cross-sectional view taken along arrow BB in Figure 3. [Figure 6] (A) Plan view, (B) Front view, and (C) View taken along arrow C, showing the segmented pieces of the socket fitting. [Figure 7] Cross-sectional view showing the pipe joint detachment prevention structure in a modified example. [Figure 8]Cross-sectional view showing a pipe joint detachment prevention structure for another modified example. [Modes for carrying out the invention]

[0009] One embodiment of this disclosure will be described with reference to the drawings.

[0010] Figure 1 is a perspective view showing an example of a pipe joint detachment prevention structure according to this disclosure. Figure 2 is a side view of the detachment prevention structure. Figure 3 is a front view of the detachment prevention structure viewed along one side AD1 in the pipe axis direction. Figure 4 is a cross-sectional view taken along the arrow AA in Figure 3. Figure 5 is a cross-sectional view taken along the arrow BB in Figure 3. In this pipe joint detachment prevention structure, a detachment prevention device 4 is attached to a pipe joint 10 formed by inserting the spigot 2 of a second pipe P2 (hereinafter referred to as pipe P2) into the socket 1 of a first pipe P1 (hereinafter referred to as pipe P1). The detachment prevention device 4 is configured to prevent detachment when an external force (detachment force) acts to detach the spigot 2 from the socket 1.

[0011] Pipe P1 is connected to pipe P2 in a sealed state via an annular sealing material 3. The socket portion 1 is formed at the end of pipe P1 on one side AD1 in the pipe axis direction. Pipe P1 includes a body portion 11 having a substantially constant outer diameter and an enlarged diameter portion 12 whose outer diameter gradually increases from the body portion 11 toward the socket portion 1. The outer diameter of the socket portion 1 is larger than the outer diameter of the body portion 11, and the enlarged diameter portion 12 connects them. In this embodiment, the outer circumferential surface of the enlarged diameter portion 12 is curved in an arc shape, convex inward in the pipe diameter direction. An insertion portion is formed at the end of pipe P1 on the other side AD2 in the pipe axis direction, similar to pipe P2.

[0012] The spigot portion 2 is formed at the end AD2 on the other side of the pipe axis direction of the pipe P2. Here, the AD1 on one side of the pipe axis direction corresponds to the direction that detaches the spigot portion 2 from the socket portion 1 (right direction in Figure 2), and the AD2 on the other side of the pipe axis direction corresponds to the direction that inserts the spigot portion 2 into the socket portion 1 (left direction in Figure 2). The pipe P2 includes a body portion 21 having a substantially constant outer diameter. The outer diameter of the spigot portion 2 is substantially the same as the outer diameter of the body portion 21. A socket portion is formed at the end AD1 on one side of the pipe axis direction of the pipe P2 via an enlarged diameter portion, similar to the pipe P1. A stopper 22 is provided on the outer circumferential surface of the spigot portion 2, facing the socket end face 13 of the pipe P1.

[0013] Pipes P1 and P2 are water pipes used as fluid pipes, but are not limited to these. They may also be gas pipes, plant piping, or other fluid pipes used for liquids other than water or gases. Furthermore, pipes P1 and P2 are made of metal, more specifically ductile cast iron, but are not limited to this. The socket fitting 5 and retaining fitting 6, described later, are also made of ductile cast iron, but are not limited to this. In this embodiment, an example is shown where the nominal diameter of pipes P1 and P2 is 1350 mm, but it goes without saying that the invention is not limited to this.

[0014] In this embodiment, the socket portion 1 has a cylindrical outer surface that extends smoothly from the outer peripheral edge 14 of the socket end face 13 toward the enlarged diameter portion 12. Here, "smoothly extended" means that it does not include steps or other parts that are intentionally provided in the design, but it may include minor roughness caused during casting or irregularities caused by the properties of the cast surface. Many pipe fittings used in ductile cast iron pipes are standardized, and standardized pipe fittings that use such a socket portion 1 include U-shaped and UF-shaped fittings. The outer diameter of the socket portion 1 is largest at the outer peripheral edge 14 and gradually decreases toward the other side AD2 in the pipe axis direction from the outer peripheral edge 14. However, it is not limited to this, and the socket shape may extend with a constant outer diameter toward the other side AD2 in the pipe axis direction from the outer peripheral edge 14.

[0015] Unlike ordinary mechanical pipe joints, this pipe joint 10 uses a flangeless socket portion 1 that does not have a flange. Further, while ordinary push-on type pipe joints use a socket portion having a stepped portion as described in Patent Documents 1 to 3, this pipe joint 10 uses a stepless socket portion 1 that does not have a stepped portion. However, the detachment prevention device 4 may be attached to a pipe joint that uses a socket portion having a stepped portion, and thereby can exert the detachment prevention function even when the height difference (outer diameter difference) of the stepped portion is so small that it interferes with engagement. As pipe joints using a socket portion having a stepped portion, T-shaped, NS-shaped, GX-shaped, and the like are standardized.

[0016] In the present embodiment, the pipe joint 10 has a U-shaped joint structure for use in jacking methods, piping in shield tunnels, and the like. For this type of pipe joint, a pipe having a nominal diameter of 800 to 2600 mm is used, for example. An annular accommodation space 15 is formed on the inner circumferential surface of the socket portion 1. The accommodation space 15 has an accommodation portion 15a having a wedge-shaped cross-section whose inner diameter decreases toward one axial side AD1. The sealing material 3 accommodated in the accommodation portion 15a is compressed between the inner circumferential surface of the socket portion 1 and the outer circumferential surface of the spigot portion 2, and seals the gap therebetween. On the other axial side AD2 of the accommodation space 15, a rear end surface 16 facing the end surface of the spigot portion 2 is formed. In this example, the enlarged diameter portion 12 is provided on the other axial side AD2 relative to the rear end surface 16. In addition to the sealing material 3, a split ring, a pressing ring, bolts, and the like are also installed in the accommodation space 15, but illustrations thereof are omitted.

[0017] The detachment prevention device 4 includes a socket fitting 5 externally fitted and mounted on the pipe P1, and a retaining fitting 6 externally fitted and mounted on the pipe P2. The socket fitting 5 has a first inner circumferential surface 51 (hereinafter referred to as inner circumferential surface 51) that engages in the pipe axial direction with the outer circumferential surface of a diameter-expanded portion 12 whose outer diameter gradually increases from the body portion 11 of the pipe P1 toward the socket portion 1. The retaining fitting 6 has a locking member 61 capable of locking onto the outer circumferential surface of the pipe P2. When a detachment force that pulls the spigot portion 2 away from the socket portion 1 acts, the socket fitting 5 and the retaining fitting 6 are engaged or connected with each other (engaged in the present embodiment) such that relative movement of the socket fitting 5 and the retaining fitting 6 in the pipe axial direction is restricted. This allows the detachment prevention function to be exerted regardless of the presence or absence of the stepped portion in the socket portion 1 and the level difference thereof.

[0018] This pipe joint 10 does not have a detachment prevention function per se, and can exert the detachment prevention function by mounting the detachment prevention device 4 thereon. Therefore, the detachment prevention device 4 can be used as a seismic reinforcement fitting that can be externally attached to the pipe joint 10. It should be noted that the pipe joint to which the detachment prevention device 4 is attached may be a pipe joint that has a detachment prevention function per se. Even in such a case, attaching the detachment prevention device 4 can further enhance the detachment prevention function of the pipe joint.

[0019] The socket fitting 5 is formed of an annular member that is mounted by covering a region including the diameter-expanded portion 12 of the pipe P1. As shown in FIG. 3, the socket fitting 5 has a split structure formed by annularly connecting a plurality of split pieces, and is configured to be capable of being externally fitted and mounted on an existing pipe P1. In the present embodiment, the socket fitting 5 is composed of four split pieces 5A to 5D, but the number of splits can be appropriately changed according to applications, sizes and the like. FIG. 6 is (A) a plan view, (B) a front view, and (C) a view along arrow C of the split piece 5A. The cross-section taken along line D-D is omitted from illustration because FIG. 5 can be referred to. The shapes of the split pieces 5B to 5D are the same as that of the split piece 5A. Adjacent split pieces are connected to each other by a connecting member 50 composed of a bolt and a nut.

[0020] The inner circumferential surface 51 of the socket fitting 5 is formed by a tapered surface that slopes along the outer circumferential surface of the enlarged diameter portion 12. The inner diameter of this tapered surface gradually increases toward one side AD1 in the pipe axis direction. In this embodiment, since the outer circumferential surface of the enlarged diameter portion 12 is curved in an arc, a gap is formed between the inner circumferential surface 51 and the outer circumferential surface of the enlarged diameter portion 12. The inner circumferential surface 51 may have a shape that creates such a gap between it and the outer circumferential surface of the enlarged diameter portion 12. The inclination angle of the inner circumferential surface 51 is preferably the same as or close to the inclination angle of the outer circumferential surface of the enlarged diameter portion 12, but is not particularly limited as long as the inner circumferential surface 51 engages with the outer circumferential surface of the enlarged diameter portion 12 and exhibits a detachment prevention function.

[0021] The socket fitting 5 has a second inner circumferential surface 52 (hereinafter, inner circumferential surface 52) located on one side AD1 in the pipe axis direction of the inner circumferential surface 51 and covering the socket portion 1, and a third inner circumferential surface 53 (hereinafter, inner circumferential surface 53) located on the other side AD2 in the pipe axis direction of the inner circumferential surface 51 and covering the body portion 11. The inner circumferential surface 52 has a relatively large diameter dimension, and the inner circumferential surface 53 has a relatively small diameter dimension. The inclination angle of the inner circumferential surface 52 and the inner circumferential surface 53 with respect to the pipe axis direction is smaller than that of the inner circumferential surface 51. This makes it easier to stabilize the position of the socket fitting 5 when it is placed over the socket portion 1. In this embodiment, the inner circumferential surface 52 and the inner circumferential surface 53 each extend substantially parallel to the pipe axis direction.

[0022] The retaining clip 6 is formed by an annular member that is fitted over the pipe P2. As shown in Figure 3, the retaining clip 6 has a split structure in which a plurality of segmented pieces are connected in an annular shape, and is configured to be fitted onto an existing pipe P2. In this embodiment, the retaining clip 6 is composed of seven segmented pieces 6A to 6G, but the number of segments can be changed as appropriate depending on the application and size. Each of the segmented pieces 6A to 6G has the same shape as the others, and each of them holds a locking member 61. Adjacent segmented pieces are connected to each other by a connector 60 composed of bolts and nuts.

[0023] The retaining clip 6 further includes a housing groove 62 in which the locking member 61 is housed, and a pressing bolt 63 which acts as a pressing member capable of pressing the locking member 61 housed in the housing groove 62 toward the inside in the diameter direction of the pipe. The locking member 61 is positioned on one side AD1 in the pipe axis direction from the stopper 22. The locking member 61 is provided with claws that protrude toward the inside in the diameter direction of the pipe. These claws are curved in an arc along the circumferential direction of the pipe and are formed to bite into the outer circumferential surface of the insertion portion 2. The outer circumferential surface of the locking member 61, which the tip of the pressing bolt 63 abuts against, has an inclined surface that becomes larger in diameter toward the receiving portion 1. Therefore, when a release force is applied, a wedge effect is produced, enhancing the locking action of the locking member 61. Note that the locking member 61 is not shown in Figure 5.

[0024] The retaining clip 6 has a hook 64 that can engage with the socket fitting 5 in the pipe axis direction when a release force is applied. The hooks 64 are provided at multiple locations in the circumferential direction of the pipe. Although not adopted in this embodiment to reduce weight, a structure in which the tips of adjacent hooks 64 in the circumferential direction of the pipe are connected to each other may be used. The hooks 64 are positioned so as to partially overlap the socket fitting 5. The tips of the hooks 64 are positioned on the other side AD2 in the pipe axis direction of a part of the socket fitting 5 (the protrusion 56 described later in this embodiment). When a release force is applied, the retaining clip 6 engages with the socket fitting 5 via the hooks 64. As a result, the relative movement between the socket fitting 5 and the retaining clip 6 is restricted, and consequently the relative movement between the socket portion 1 and the insertion portion 2 is restricted.

[0025] When attaching the detachment prevention device 4 to the pipe joint 10, the receiving fitting 5 should be fitted onto the pipe P1 first, and then the retaining fitting 6 should be fitted onto the pipe P2 so that it partially overlaps the receiving fitting 5. When fitting the receiving fitting 5 onto the pipe P1, the segmented pieces 5A to 5D can be loosely connected around the body portion 11 of the pipe P1 to form an annular body, which can then be moved to one side AD1 in the pipe axis direction and placed over the enlarged diameter portion 12, after which the connector 50 can be tightened firmly. In this embodiment, the engagement between the receiving fitting 5 and the retaining fitting 6, and the engagement between the receiving portion 1 and the receiving fitting 5 are both metal-to-metal contact, and there is no need to torque-manage these engagement forces, thus reducing variations in performance due to the operator.

[0026] The socket fitting 5 is provided with a load-receiving surface 54 that receives the load from the hook 64 when a release force is applied. In this embodiment, the load-receiving surface 54 is included in the side surface AD2 on the other side in the pipe axial direction of the protrusion 56, which will be described later. If the load-receiving surface 54 is located at the same position as the socket end face 13 or further to the other side AD1 in the pipe axial direction, there is a risk that the socket fitting 5 will lift up when a strong release force is applied. In contrast, in this embodiment, since the load-receiving surface 54 is provided at a position away from the socket end face 13 to the other side AD2 in the pipe axial direction, such lifting of the socket fitting 5 can be suppressed.

[0027] Furthermore, in this embodiment, as shown in Figure 4, the load-receiving surface 54 is located on the outer side of the receiving portion 1 in the diameter direction of the pipe, so there is no need to provide space on one side AD1 of the receiving end face 13 in the pipe axis direction for engaging the retaining clip 6 with the receiving fitting 5. As a result, it becomes possible to position the retaining clip 6 close to the receiving end face 13, and the overall length of the detachment prevention device 4 becomes more compact. Therefore, for example, at a construction site where the detachment prevention device 4 is attached to the pipe joint 10, it is convenient to avoid interference between the detachment prevention device 4 and obstacles around the pipe joint 10.

[0028] The socket fitting 5 has a dividing portion 5s that divides the socket fitting 5 in the circumferential direction of the pipe, and a flange-shaped boss portion 55 formed on the dividing portion 5s. The dividing portion 5s is provided at multiple locations in the circumferential direction of the pipe, and in this embodiment, it is provided at four locations. The connector 50 is attached to the boss portion 55. As can be seen from Figures 1, 2, 4 and 6, the boss portion 55 is provided in a position that does not interfere with the hook 64 in the circumferential direction of the pipe. The boss portion 55 is positioned further to the other side AD2 in the pipe axis direction than the end portion 5E on one side AD1 of the socket fitting 5 in the pipe axis direction, and is not provided in a region R of a predetermined length from the end portion 5E (see Figure 6). The end portion 5E is located on the other side AD2 in the pipe axis direction than the socket end face 13.

[0029] In this embodiment, as described above, the boss portion 55 is positioned so as not to interfere with the hook 64 in the circumferential direction of the pipe. With this configuration, even when the retaining clip 6 is attached, the receiving fitting 5 can be rotated along the circumferential direction of the pipe. Therefore, at a construction site where the detachment prevention device 4 is attached to the pipe joint 10, if there is an obstacle around the pipe joint 10 that would interfere with the boss portion 55, even after the retaining clip 6 has been attached, it is possible to avoid interference with the obstacle by rotating the receiving fitting 5 to adjust the position of the boss portion 55.

[0030] The socket fitting 5 has a projection 56 that protrudes outward in the diameter direction of the pipe. The outer diameter of the projection 56 is larger than the inner diameter of the tip of the hook 64. The hook 64 is positioned so as to overlap the projection 56. The load-receiving surface 54 provided on the projection 56 is located further away AD2 in the other direction in the pipe axis direction than the socket end face 13. The boss portion 55 is also located further away AD2 in the other direction in the pipe axis direction than the projection 56. The tip of the hook 64 is positioned in the gap 57 between the boss portion 55 and the projection 56 so as to engage with the projection 56 in the pipe axis direction when a release force is applied. Since the gap 57 is part of the region R described above, it does not include any portion that interferes with the hook 64 along the circumferential direction of the pipe.

[0031] In this embodiment, the size of the gap 57 in the pipe axis direction is greater than the thickness of the tip of the hook 64. With this configuration, the gap 57 provides a range of motion for the hook 64, and the pipe joint 10 is given an expansion and contraction function, thereby improving seismic resistance. In Figure 4, the hook 64 is in contact with the protrusion 56 (the load-receiving surface 54 of it), but it is not limited to this, and the hook 64 may be positioned away from the protrusion 56 toward the other side AD2 in the pipe axis direction. In that case, when the insertion part 2 attempts to detach from the receiving part 1 due to the action of a detachment force, the hook 64 moves relative to it and engages with the protrusion 56, thereby providing a detachment prevention function. The range of motion of the hook 64 at that time becomes the expansion and contraction range of the pipe joint 10.

[0032] When a detachment force is generated, the inner circumferential surface 51 of the socket fitting 5 strongly engages with the outer circumferential surface of the enlarged diameter portion 12, causing the divided portion 5s of the socket fitting 5 to open due to a wedge action. In this embodiment, the boss portion 55 is provided over an area that covers the inner circumferential surface 51 in the direction of the pipe axis (see Figure 4), and this configuration is effective in preventing the inconvenience of the divided portion 5s opening. Furthermore, reinforcing ribs 58 that contribute to improving the strength of the socket fitting 5 are provided in the area that covers the inner circumferential surface 51, and this is also effective in preventing the above inconvenience. In this embodiment, the reinforcing ribs 58 include a reinforcing rib 58a that extends in the direction of the pipe circumferential direction and a reinforcing rib 58b that intersects with it and extends in the direction of the pipe axis.

[0033] The boss portion 55 has a plurality of mounting holes for attaching the connector 50, and in this embodiment, four mounting holes H1 to H4 are formed. As shown in Figure 4, these mounting holes include mounting hole H1 located on one side AD1 in the pipe axial direction relative to the inner circumferential surface 51, and mounting hole H4 located on the other side AD2 in the pipe axial direction relative to the inner circumferential surface 51. The other mounting holes H2 and H3 are set between mounting holes H1 and H4. With this configuration, the parts of the boss portion 55 with high fastening strength (mounting holes to which the connector 50 is attached) are set to sandwich the inner circumferential surface 51 in the pipe axial direction, so the inconvenience of the divided portion 5s opening due to the action of detachment force can be effectively prevented.

[0034] In this embodiment, the socket fitting 5 is provided with a retaining member 7 that protrudes from the inner circumferential surface of the socket fitting 5 (in this embodiment, the inner circumferential surface 52) and can be locked onto the outer circumferential surface of the socket portion 1 (see Figure 5). With this configuration, when attaching the detachment prevention device 4 to the pipe joint 10, misalignment of the socket fitting 5 with respect to the socket portion 1 can be suppressed, thereby improving workability. The retaining member 7 is a screw member that is attached to a through hole 70 formed in the socket fitting 5, and its protrusion amount is adjustable. The through hole 70 is formed at multiple locations in the circumferential direction of the pipe (see Figure 6). The tip of the retaining member 7 may be provided with a claw that protrudes inward in the diameter direction of the pipe.

[0035] Modified examples of pipe joint detachment prevention devices and detachment prevention structures will be explained with reference to Figures 7 and 8.

[0036] Figure 7 is a cross-sectional view showing a modified pipe joint detachment prevention structure. Figures 7(A) and 7(B) show cross-sections at different positions in the circumferential direction of the pipe. In the above-described embodiment, an example was shown in which the hook 64 of the retaining fitting 6 is formed from a component that constitutes the main body 65 that holds the locking member 61, but the invention is not limited to this. For example, as shown in Figure 7, the hook 64 of the retaining fitting 6 may be formed from a component separate from the main body 65 that holds the locking member 61. In this modified example, the hook 64 and the main body 65 are connected and fixed to each other by a connector 8 composed of a bolt and a nut.

[0037] Figure 8 is a cross-sectional view showing a pipe joint detachment prevention structure according to another modified example. Figures 8(A) and (B) show cross-sections at different positions in the circumferential direction of the pipe. In the example shown in Figure 8, the socket fitting 5 and the retaining fitting 6 are connected to each other. The socket fitting 5 is provided with a flange 59. The flange 59 faces the body 65 of the retaining fitting 6, and they are connected and fixed by a connector 9. The connector 9 consists of a bolt and a nut. Such connecting and fixing parts are provided at multiple locations in the circumferential direction of the pipe. In this example, the flange 59 is located on one side AD1 in the pipe axial direction relative to the socket end face 13, but it is not limited to this. The body 65 of the retaining fitting 6 can be made from the same material as in Figure 7.

[0038] Those skilled in the art will understand that the embodiments described above are specific examples of the following embodiments.

[0039] [1] The pipe joint detachment prevention device of this disclosure is a pipe joint detachment prevention device comprising a socket portion of a first pipe into a socket portion of a second pipe, and includes a socket fitting fitted externally on the first pipe and a retaining fitting fitted externally on the second pipe. The socket fitting has a first inner circumferential surface that engages in the pipe axis direction with the outer circumferential surface of an enlarged diameter portion of the first pipe, which gradually increases in outer diameter from the body portion toward the socket portion. The retaining fitting has a locking member that can be locked to the outer circumferential surface of the second pipe. The socket fitting and the retaining fitting are engaged or connected to each other such that relative movement between the socket fitting and the retaining fitting in the pipe axis direction is restricted when a detachment force is applied that detaches the socket portion from the socket portion. With this configuration, the detachment prevention function can be performed regardless of the presence or absence of a stepped portion or difference in height of the socket portion.

[0040] [2] In the detachment prevention device described in [1] above, the first inner circumferential surface may be formed by a tapered surface that slopes along the outer circumferential surface of the enlarged diameter portion. This makes it easier to properly engage the first inner circumferential surface of the socket fitting with the outer circumferential surface of the enlarged diameter portion in the pipe axis direction.

[0041] [3] In the detachment prevention device described in [1] or [2] above, the socket fitting may have a second inner surface located on one side of the first inner surface in the axial direction of the pipe and covering the socket portion, and a third inner surface located on the other side of the first inner surface in the axial direction of the pipe and covering the body portion, wherein the second inner surface and the third inner surface each have a smaller inclination angle with respect to the axial direction of the pipe compared to the first inner surface. This makes it easier to stabilize the position of the socket fitting placed over the socket portion.

[0042] [4] In the detachment prevention device described in [3] above, the second inner surface and the third inner surface may each extend substantially parallel to the pipe axis direction. This makes it easier to stabilize the position of the socket fitting placed over the socket.

[0043] [5] In any one of the above [1] to [4] anti-detachment devices, the retaining clip may have a hook that can engage with the receiving clip in the pipe axis direction when the detachment force is applied. With this configuration, when the detachment force is applied, the retaining clip engages with the receiving clip via the hook.

[0044] [6] In the detachment prevention device described in [5] above, the receiving fitting may have a divided portion that divides the receiving fitting in the circumferential direction of the pipe, and a flange-shaped boss portion formed on the divided portion, wherein the boss portion is provided in a position that does not interfere with the hook in the circumferential direction of the pipe. With such a configuration, even when the retaining fitting is attached, the receiving fitting can be rotated along the circumferential direction of the pipe as needed, which is useful when it is necessary to avoid interference with obstacles at the construction site.

[0045] [7] In the detachment prevention device described in [5] or [6] above, the socket fitting may have a dividing portion that divides the socket fitting in the circumferential direction of the pipe, a flange-shaped boss portion formed on the dividing portion, and a protrusion that protrudes outward in the radial direction of the pipe, and the tip of the hook may be positioned in the gap between the boss portion and the protrusion so as to engage with the protrusion in the axial direction of the pipe when the detachment force is applied, and the size of the gap in the axial direction of the pipe is greater than the thickness of the tip of the hook. With such a configuration, a gap is provided for the movement of the hook, and the pipe joint is given an expansion and contraction function, thereby improving seismic resistance.

[0046] [8] In any one of the above [1] to [7] anti-detachment devices, the receiving fitting may have a divided portion that divides the receiving fitting in the circumferential direction of the pipe, and a flange-shaped boss portion formed on the divided portion, wherein the boss portion is provided over an area that covers the first inner circumferential surface in the axial direction of the pipe. With such a configuration, the inconvenience of the divided portion of the receiving fitting opening up due to the generation of a detachment force can be effectively prevented.

[0047] [9] In the detachment prevention device described in [8] above, the boss portion may have a plurality of mounting holes, including a mounting hole located on one side in the pipe axis direction relative to the first inner circumferential surface and a mounting hole located on the other side in the pipe axis direction relative to the first inner circumferential surface. With this configuration, the inconvenience of the divided portion of the receiving fitting opening up due to the generation of a detachment force can be effectively prevented.

[0048]

[10] The pipe joint detachment prevention structure of this disclosure is a pipe joint formed by inserting the spigot portion of the second pipe into the socket portion of the first pipe, and having one of the above-mentioned detachment prevention devices [1] to [9] attached to it. With this configuration, the detachment prevention function can be performed regardless of the presence or absence of a step in the socket portion or the difference in height.

[0049]

[11] In the detachment prevention structure described in

[10] above, the socket portion may have a cylindrical outer surface that extends smoothly from the outer peripheral edge of the socket end face toward the enlarged diameter portion. The detachment prevention function can be appropriately performed even in a pipe joint using such a socket portion.

[0050] While embodiments of the pipe joint detachment prevention device and detachment prevention structure relating to this disclosure have been described with reference to the drawings, it should be understood that the specific configuration is not limited to these embodiments. The scope of this disclosure is indicated not only by the above-described embodiments but also by the claims, and furthermore, all modifications within the meaning and scope of equivalence to the claims.

[0051] The pipe joint detachment prevention device and detachment prevention structure described herein are not limited in any way to the embodiments described above, nor are they limited to the effects described above. The pipe joint detachment prevention device and detachment prevention structure described herein can be modified in various ways without departing from the spirit thereof. Furthermore, the various components adopted in the embodiments described above can be arbitrarily combined and adopted. [Explanation of Symbols]

[0052] 1 Receiving part, 2 Insertion part, 3 Sealing material, 4 Detachment prevention device, 5 Receiving fitting, 5s Dividing part, 6 Removal fitting, 7 Retaining member, 10 Pipe joint, 11 Body part, 12 Enlarged diameter part, 13 Receiving end face, 14 Outer circumference edge, 51 First inner surface, 52 Second inner surface, 53 Third inner surface, 55 Boss part, 56 Protrusion, 57 Gap, 61 Locking member, 64 Hook, AD1 One side in the pipe axis direction, AD2 The other side in the pipe axis direction, P1 First pipe, P2 Second pipe

Claims

1. A pipe joint detachment prevention device comprising inserting the spigot of a second pipe into the socket of a first pipe, The device comprises a receiving fitting fitted onto the first pipe and a retaining fitting fitted onto the second pipe, The socket fitting has a first inner surface that engages in the axial direction with the outer surface of the enlarged diameter portion of the first pipe, which gradually increases in outer diameter from the body portion of the first pipe toward the socket portion. The retaining clip has a locking member that can be locked onto the outer surface of the second pipe, A pipe joint detachment prevention device, wherein the receiving fitting and the retaining fitting are engaged or connected to each other such that when a detachment force is applied that detaches the insertion portion from the receiving portion, the relative movement of the receiving fitting and the retaining fitting in the pipe axis direction is restricted.

2. The pipe joint detachment prevention device according to claim 1, wherein the first inner circumferential surface is formed by a tapered surface that slopes along the outer circumferential surface of the enlarged diameter portion.

3. The socket fitting has a second inner surface located on one side of the first inner surface in the axial direction of the pipe and covering the socket portion, and a third inner surface located on the other side of the first inner surface in the axial direction of the pipe and covering the body portion. The pipe joint detachment prevention device according to claim 1, wherein the second inner surface and the third inner surface each have a smaller angle of inclination with respect to the pipe axis direction compared to the first inner surface.

4. The pipe joint detachment prevention device according to claim 3, wherein the second inner surface and the third inner surface each extend substantially parallel to the pipe axis direction.

5. The pipe joint detachment prevention device according to claim 1, wherein the retaining fitting has a hook that can engage with the receiving fitting in the pipe axis direction when the detachment force is applied.

6. The socket fitting has a dividing portion that divides the socket fitting in the circumferential direction of the pipe, and a flange-shaped boss portion formed on the dividing portion. The pipe joint detachment prevention device according to claim 5, wherein the boss portion is provided in a position that does not interfere with the hook in the circumferential direction of the pipe.

7. The aforementioned socket fitting has a dividing portion that divides the socket fitting in the circumferential direction of the pipe, a flange-shaped boss portion formed on the dividing portion, and a protrusion that protrudes outward in the radial direction of the pipe. The tip of the hook is positioned in the gap between the boss and the protrusion so as to engage with the protrusion in the axial direction of the pipe when the release force is applied. The pipe joint detachment prevention device according to claim 5, wherein the size of the gap in the pipe axis direction is greater than the thickness of the tip of the hook.

8. The socket fitting has a dividing portion that divides the socket fitting in the circumferential direction of the pipe, and a flange-shaped boss portion formed on the dividing portion. The pipe joint detachment prevention device according to claim 1, wherein the boss portion is provided over an area that covers the first inner circumferential surface in the pipe axial direction.

9. The pipe joint detachment prevention device according to claim 8, wherein the boss portion has a plurality of mounting holes, including a mounting hole located on one side in the pipe axial direction relative to the first inner circumferential surface and a mounting hole located on the other side in the pipe axial direction relative to the first inner circumferential surface.

10. A pipe joint detachment prevention structure, wherein a detachment prevention device according to any one of claims 1 to 9 is attached to a pipe joint formed by inserting the spigot portion of a second pipe into the socket portion of a first pipe.

11. The pipe joint detachment prevention structure according to claim 10, wherein the receiving portion has a cylindrical outer surface that extends smoothly from the outer peripheral edge of the receiving end face toward the enlarged diameter portion.

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