Method for assembling expansion joints and temporary fixing structure for lock rings

Abstract

To provide an assembling method of a telescopic pipe joint which can improve the attachment workability of a lock ring, and a temporary fixing structure of the lock ring.SOLUTION: In an assembling method of a telescopic pipe joint 10 in which a pipe body 1 and a pipe body 2 inserted therein are relatively movably connected to each other within a constant range along an axial core direction, and which exerts a release prevention function by a lock ring 4 which is attached to an external peripheral face of the pipe body 2, the assembling method comprises: a temporary fixing step for internally fitting an assembling body 48 in which the lock ring 4 expanded in a diameter by an elastic deformation is assembled to a temperature fixing jig 8 into the pipe body 1, and holding the diameter-expanded lock ring 4 at a posture coaxially with the pipe body 1; and an attachment step for inserting the diameter-expanded lock ring 4 into the pipe body 2, releasing the temporary fixing jig 8 from the lock ring 4 by the insertion movement of the pipe body 2, and attaching the lock ring 4 to the external peripheral face of the pipe body 2.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present disclosure relates to an assembling method of a telescopic pipe joint and a temporary fixing structure of a lock ring used in the method.

Background Art

[0002] Patent Documents 1 and 2 describe telescopic pipe joints each having a telescopic function. According to such a telescopic pipe joint, a first pipe body and a second pipe body inserted therein are connected so as to be relatively movable within a certain range along the axial direction. A lock ring (ring member) extending along the circumferential direction is attached to the outer peripheral surface of the second pipe body. When the second pipe body attempts to relatively move beyond a certain range in the direction of separating from the first pipe body, the lock ring engages with an engaged portion formed inside the first pipe body, thereby restricting the relative movement and preventing the separation.

[0003] In order to exhibit the above-described separation preventing function, the outer diameter of the lock ring is set larger than the inner diameter of the engaged portion. Therefore, as shown in Patent Documents 1 and 2, the operation of attaching the lock ring to the outer peripheral surface of the second pipe body is performed in a state where they are disposed inside the first pipe body. In Patent Document 1, a method is proposed in which a tool is used to rotate the lock ring, and a female screw formed on the inner peripheral surface of the lock ring is screwed onto a male screw formed on the outer peripheral surface of the second pipe body. In Patent Document 2, a method is proposed in which a tool is used to expand the diameter of the lock ring, and the expanded lock ring is externally fitted to the second pipe body.

[0004] The methods described in Patent Documents 1 and 2 require a relatively complicated procedure: inserting a tool from the opening opposite to the opening into which the second pipe is inserted, and manipulating it to rotate or expand the lock ring. Moreover, if the opening into which the tool is inserted is formed at the end of an axially extending choke (see, for example, Figure 1), and / or if the pipe has a small diameter (for example, nominal diameter of 100 or less), the tool must be passed through a narrow space to operate the lock ring, making it difficult to handle with existing tools. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2-271192 [Patent Document 2] Japanese Patent Application Publication No. 10-54487 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] This disclosure has been made in view of the above circumstances, and its purpose is to provide an assembly method for an expansion joint that can improve the ease of attaching a lock ring, and a temporary fixing structure for a lock ring. [Means for solving the problem]

[0007] [1] The method for assembling an expansion joint according to this disclosure is a method for assembling an expansion joint in which a first pipe body and a second pipe body inserted therein are connected so as to be able to move relative to each other within a certain range along the axial direction, and a lock ring attached to the outer surface of the second pipe body provides a function to prevent separation, comprising: a temporary fixing step of fitting an assembly body formed by assembling the lock ring, which has been expanded in diameter by elastic deformation, onto a temporary fixing jig into the first pipe body and holding the expanded lock ring in a position concentric with the first pipe body; and a mounting step of inserting the second pipe body into the expanded lock ring, removing the temporary fixing jig from the lock ring by the insertion and movement of the second pipe body, and attaching the lock ring to the outer surface of the second pipe body.

[0008] According to this method, the expanded lock ring is temporarily fixed inside the first pipe in a concentric position with the first pipe, and the second pipe is inserted into the expanded lock ring, thereby attaching the lock ring to the outer surface of the second pipe. As a result, it is no longer necessary to insert a tool from the opening opposite to the opening into which the second pipe is inserted, thereby improving the ease of attaching the lock ring.

[0009] [2] In the assembly method of the expansion joint described in [1] above, the lock ring has a divided portion that divides the lock ring in the circumferential direction, and the temporary fixing jig has a main body formed to fit inside the first pipe body and a first protrusion protruding from the main body, and in the temporary fixing step, it is preferable that the lock ring is held in an expanded state by inserting the first protrusion into the divided portion whose gap has been enlarged by elastic deformation. With this method, the lock ring in an expanded state can be held in a predetermined position using a temporary fixing jig with a simple configuration.

[0010] [3] In the assembly method of the expansion joint described in [1] or [2] above, the temporary fixing jig has a main body formed to fit inside the first pipe body and a second projection protruding from the main body, and it is preferable that in the temporary fixing step, the lock ring is assembled to the temporary fixing jig with the lock ring resting against the second projection. By resting the lock ring against the second projection, it can be used for positioning when assembling the lock ring to the temporary fixing jig. In addition, the relative position of the lock ring assembled to the temporary fixing jig is stabilized, improving work efficiency.

[0011] [4] In any one of the above methods for assembling an expansion joint [1] to [3], in the mounting step, it is preferable to press the temporary fixing jig with the second pipe and remove it from the lock ring while the lock ring is engaged with the engaged portion formed inside the first pipe in the insertion direction of the second pipe. With this method, the temporary fixing jig can be smoothly removed from the lock ring by the insertion movement of the second pipe, thus improving work efficiency.

[0012] [5] In any one of the above methods for assembling an expansion joint [1] to [4], the first pipe body comprises a casing having a spherical inner surface and an intermediate sleeve having a spherical outer surface that is slidably fitted relative to the spherical inner surface, and in the temporary fixing step, the assembly body may be fitted inside the intermediate sleeve. In this case, the ease of attaching the lock ring can be improved when assembling an expansion joint (flexible expansion joint) that has a bending function in addition to the expansion function. Furthermore, it becomes possible to pre-fit the assembly body into the intermediate sleeve before fitting the intermediate sleeve into the casing, thereby improving work efficiency.

[0013] [6] In the assembly method of the expansion joint described in [5] above, the intermediate sleeve has a notch that allows the lock ring to pass through in a position where its radial direction is aligned with the axial direction of the intermediate sleeve, and in the temporary fixing step, it is preferable to fit the temporary fixing jig into the notch. With this method, the assembly can be fitted into the intermediate sleeve by utilizing the notch formed in the intermediate sleeve.

[0014] [7] The temporary fixing structure for a lock ring according to this disclosure is a temporary fixing structure for assembling an expansion joint in which a first pipe and a second pipe inserted therein are connected so as to be able to move relative to each other within a certain range along the axial direction, and a lock ring attached to the outer surface of the second pipe provides a function to prevent detachment. The assembly, which is made by assembling the lock ring, which has been expanded in diameter by elastic deformation, to a temporary fixing jig, is fitted inside the first pipe, and the expanded lock ring is held in a position concentric with the first pipe. When the second pipe is inserted into the expanded lock ring, the temporary fixing jig is removed from the lock ring by the insertion movement of the second pipe, and the lock ring is attached to the outer surface of the second pipe.

[0015] With this structure, an expanded lock ring is temporarily fixed inside the first tube in a concentric position with the first tube, and the second tube is inserted into the expanded lock ring, thereby attaching the lock ring to the outer surface of the second tube. As a result, it is no longer necessary to insert a tool from the opening opposite to the opening into which the second tube is inserted, thereby improving the ease of attaching the lock ring.

[0016] [8] In the temporary fixing structure for the lock ring described in [7] above, the lock ring has a dividing portion that divides the lock ring in the circumferential direction, and the temporary fixing jig has a main body formed to fit inside the first tube and a first projection protruding from the main body, and it is preferable that the lock ring is held in an expanded diameter state by inserting the first projection into the dividing portion, which has a larger gap due to elastic deformation. With this configuration, the lock ring in an expanded diameter state can be held in a predetermined position using a temporary fixing jig with a simple configuration.

[0017] [9] In the temporary fixing structure for the lock ring described in [7] or [8] above, it is preferable that the temporary fixing jig has a main body formed to fit inside the first tubular body and a second projection protruding from the main body, and that the lock ring is assembled to the temporary fixing jig with the lock ring resting against the second projection. By resting the lock ring against the second projection, it can be used for positioning when assembling the lock ring to the temporary fixing jig. In addition, the relative position of the lock ring assembled to the temporary fixing jig is stabilized, improving work efficiency.

[0018]

[10] In any one of the above [7] to [9] temporary locking structures for the locking ring, it is preferable that an engaging portion is formed inside the first tube so that the enlarged locking ring faces the insertion direction of the second tube. With this configuration, the temporary locking jig can be smoothly removed from the locking ring by the insertion movement of the second tube, thus improving work efficiency.

[0019]

[11] In the temporary fixing structure of any one of the above [7] to

[10] lock rings, the first pipe body includes a casing having a spherical inner peripheral surface and an intermediate sleeve having a spherical outer peripheral surface that is slidably fitted relative to the spherical inner peripheral surface thereof, and the assembly may be fitted inside the intermediate sleeve. In this case, in the assembly of a telescopic pipe joint (telescopic flexible pipe joint) having a bending function in addition to the telescopic function, the workability of attaching the lock ring can be improved. Further, before fitting the intermediate sleeve to the casing, it becomes possible to previously fit the assembly inside the intermediate sleeve, improving the workability.

[0020]

[12] In the temporary fixing structure of the lock ring of the above

[11] , a notch portion that allows the passage of the lock ring in a posture where the radial direction coincides with the axial direction of the intermediate sleeve is formed in the intermediate sleeve, and it is preferable that the temporary fixing jig is fitted into the notch portion. According to such a configuration, the assembly can be fitted inside the intermediate sleeve by using the notch portion formed in the intermediate sleeve.

Brief Description of the Drawings

[0021] [Figure 1] Cross-sectional view showing an example of the configuration of a telescopic pipe joint [Figure 2] (A) Front view and (B) Cross-sectional view taken along the line A-A of the lock ring in the natural state [Figure 3] Diagram explaining the inconvenience when assembling a telescopic pipe joint by a conventional method [Figure 4] Cross-sectional view explaining the temporary fixing process [Figure 5] Cross-sectional view explaining the mounting process [Figure 6] Cross-sectional view showing the operation of fitting the assembly inside the intermediate sleeve [Figure 7] (A) Rear view and (B) Cross-sectional view taken along the line B-B of the intermediate sleeve [Figure 8] (A) Front view and (B) Side view of the temporary fixing jig [Figure 9] Front view of the assembly [Figure 10] [[ID= [Figure 11] Figure 10 shows (A) an exploded front view and (B) an exploded side view of the main body. [Figure 12] Cross-sectional view showing another embodiment of the expansion joint. [Figure 13] Cross-sectional view showing another embodiment of the expansion joint. [Modes for carrying out the invention]

[0022] This disclosure describes an assembly method for an expansion joint and an embodiment of a temporary fixing structure for a lock ring.

[0023] [Structure of expansion joint] The structure of the expansion joint will be described with reference to Figures 1 and 2. The expansion joint 10 shown in Figure 1 comprises a pipe body 1 (first pipe body), a pipe body 2 (second pipe body) inserted into it, and an annular packing 3 that seals the space between them. Pipe body 1 and pipe body 2 are connected so that they can move relative to each other within a certain range along the axial direction (left-right direction in Figure 1). In this embodiment, pipe body 1 and pipe body 2 are shown as examples of cast iron pipes with a nominal diameter of 75, which are used as water pipes. However, pipe bodies 1 and 2 may be fluid pipes used for liquids other than water, gases, or gas-liquid mixtures. In addition, specifications such as pipe dimensions can be appropriately changed according to the usage conditions.

[0024] The tube 1 has a pair of openings 1a and 1b formed at both ends. Opening 1a is formed at the end of the receiving end of the tube 1. Opening 1b is formed at the end of the insertion end of the tube 1 that extends in the axial direction. The tube 2 is inserted into the tube 1 through opening 1a. Opening 1a includes the opening 6a of the intermediate sleeve 6 (see Figures 6 and 7), which will be described later. The insertion direction D1 is the direction in which the tube 2 is inserted into the tube 1, and corresponds to the right direction in Figure 1. The removal direction D2 is the direction in which the tube 2 is removed from the tube 1, and corresponds to the left direction in Figure 1. Furthermore, the view along the insertion direction D1 is the front view, and the view along the removal direction D2 is the rear view.

[0025] A locking ring 4 is fitted to the outer surface of the tube body 2. The locking ring 4 extends along the circumferential direction around the axis. The locking ring 4 is made of a metal such as steel. An annular groove 21 for fitting the locking ring 4 is formed on the outer surface of the tube body 2. The locking ring 4 is fixed to the tube body 2 by being fitted into the annular groove 21. The annular groove 21 is formed at a position away from the tip of the tube body 2 in the outward direction D2. Since the depth of the annular groove 21 is less than the thickness of the locking ring 4, the locking ring 4 is fitted and fixed in a state where it protrudes from the annular groove 21.

[0026] As shown in Figure 2, the lock ring 4 has a dividing portion 41 that divides the lock ring 4 in the circumferential direction. In this embodiment, the lock ring 4 is formed from a C-shaped ring member, and the dividing portion 41 is set at one location in the circumferential direction. The inner diameter of the lock ring 4 in its natural state without any external force applied is smaller than the outer diameter of the pipe body 2. Therefore, when the lock ring 4 is fitted onto the pipe body 2, the gap between the dividing portion 41 is increased by elastic deformation, thereby expanding the diameter of the lock ring 4. Insertion holes 42 are provided at each of the pair of ends that sandwich the dividing portion 41. A tool 34 (see Figure 6(B)) for expanding the diameter of the lock ring 4 is inserted into the insertion holes 42.

[0027] Notches 43 are provided on the inner circumferential surface of the lock ring 4 so that the lock ring 4 can be smoothly expanded in diameter by elastic deformation. The notches 43 are formed in such a way that they partially reduce the thickness of the lock ring 4. The notches 43 extend in the circumferential direction within a predetermined angular range, and both ends of their inner surface are curved in an arc shape. The notches 43 are formed at multiple locations (three locations in this embodiment) in the circumferential direction. As the diameter of the lock ring 4 decreases, a larger force is required to expand it, so the shape of the lock ring 4 with such notches 43 is particularly useful when the pipe body 2 has a small diameter (for example, nominal diameter of 100 or less).

[0028] The expansion joint 10 exhibits a detachment prevention function through a lock ring 4 attached to the outer surface of the pipe body 2. When the pipe body 2 attempts to move relative to the pipe body 1 beyond a certain range in the direction of detachment, the lock ring 4 engages with an engaging portion 11 formed inside the pipe body 1, thereby restricting relative movement and preventing detachment. The engaging portion 11 is formed by an annular wall portion that defines the mounting groove 12 into which the packing 3 is fitted, and protrudes toward the inner circumference. The inner diameter of the engaging portion 11 (annular wall portion) is larger than the outer diameter of the pipe body 2 and smaller than the outer diameter of the lock ring 4 attached to the outer surface of the pipe body 2.

[0029] In this embodiment, an example is shown in which the expansion joint 10 is an expansion joint (flexible expansion joint) that has a bending function in addition to an expansion function. The pipe body 1 comprises a casing 5 having a spherical inner surface, an intermediate sleeve 6 having a spherical outer surface that is slidably fitted relative to the spherical inner surface, and an annular packing 7 that seals the space between them. The expansion joint 10 is configured to be expandable by sliding between the intermediate sleeve 6 and the pipe body 2, and to bend by sliding between the casing 5 and the intermediate sleeve 6. However, as shown in the modified examples described later, the expansion joint to which this disclosure applies is not limited to one that has a bending function.

[0030] The process of attaching the lock ring 4 to the outer surface of the pipe body 2 requires that the lock ring 4 and the portion of the pipe body 2 to which it will be attached be positioned inside the pipe body 1. However, according to the method described in Patent Document 2, the lock ring 4 must be operated by inserting a tool 35 through the opening 1b as shown in Figure 3, which makes the process complicated. In particular, if the opening 1b is formed at the end of the choke or if the pipe body 1 has a small diameter, it is extremely difficult to operate the lock ring 4 by passing the tool 35 through the narrow space. Therefore, in this embodiment, the expansion joint 10 is assembled by the method described below so that the lock ring 4 can be easily attached.

[0031] [Method for assembling expansion joints] The assembly method of the expansion joint 10 will be described with reference to Figures 4 to 9. The assembly method of the expansion joint 10 in this embodiment includes a temporary fixing step (see Figure 4) in which an assembly body 48, which is made by attaching a lock ring 4 expanded by elastic deformation to a temporary fixing jig 8, is fitted into the pipe body 1 and the expanded lock ring 4 is held in a position concentric with the pipe body 1, and a mounting step (see Figure 5) in which the pipe body 2 is inserted into the expanded lock ring 4, the temporary fixing jig 8 is removed from the lock ring 4 by the insertion and movement of the pipe body 2, and the lock ring 4 is attached to the outer surface of the pipe body 2.

[0032] According to this method, as shown in Figure 4, the expanded lock ring 4 is temporarily fixed inside the pipe 1 in a concentric position with the pipe 1. Then, as shown in Figure 5, the lock ring 4 is attached to the outer surface of the pipe 2 by inserting the pipe 2 into the expanded lock ring 4. Therefore, there is no need to insert a tool through the opening 1b of the pipe 1 to operate the lock ring 4. Consequently, the above-mentioned inconveniences do not occur whether the opening 1b is formed at the end of the choke or whether the pipe 1 has a small diameter. Thus, the ease of attaching the lock ring 4 can be improved. This improvement effect is particularly noticeable when the pipe 1 has a small diameter (for example, nominal diameter of 100 or less).

[0033] In this assembly method, a temporary fixing jig 8 is used to temporarily fix the enlarged lock ring 4. The temporary fixing jig 8 is configured to be fitted inside the pipe 1. Furthermore, when the temporary fixing jig 8 is fitted inside the pipe 1, it is configured to hold the enlarged lock ring 4 in a concentric position with the pipe 1. Here, "fitting inside" means fitting it inside the mating member (the pipe 1 in this embodiment), and a gap may be provided between them. The temporary fixing jig 8 is removed from the lock ring 4 during the mounting process as shown in Figure 5(B), and is then recovered.

[0034] In this embodiment, the pipe body 1 comprises a casing 5 and an intermediate sleeve 6, and as shown in Figure 4, the assembly 48 is fitted inside the intermediate sleeve 6 of the pipe body 1. Therefore, as shown in Figure 6, it is possible to pre-fit the assembly 48 into the intermediate sleeve 6 before fitting the intermediate sleeve 6 into the casing 5. By fitting the intermediate sleeve 6 with the assembly 48 fitted inside (see Figure 6(C)) into the casing 5, the pipe body 1 with the assembly 48 fitted inside can be obtained as shown in Figure 4. This method offers better workability compared to fitting the assembly 48 into the intermediate sleeve 6 after it has been fitted into the casing 5.

[0035] To fit the assembly 48 into the intermediate sleeve 6, first, the lock ring 4 is placed inside the intermediate sleeve 6 as shown in Figure 6(A). The lock ring 4 is positioned in the annular circumferential groove 13 formed on the insertion direction D1 side of the engaged portion 11. The inner diameter of the annular circumferential groove 13 is set to be larger than the outer diameter of the lock ring 4. As previously described, the inner diameter of the engaged portion 11 is smaller than the outer diameter of the lock ring 4, so the lock ring 4 is inserted into the intermediate sleeve 6 from the opening 6b located on the insertion direction D1 side of the pair of openings 6a and 6b formed at both ends of the intermediate sleeve 6.

[0036] As shown in Figure 7, the opening 6b of the intermediate sleeve 6 is provided with a notch 61 that partially increases its diameter. The diameter D61 of the notch 61 is set to be equal to or greater than the outer diameter D4 of the lock ring 4 (see Figure 2). Therefore, the intermediate sleeve 6 has a notch 61 that allows the lock ring 4 (see the dashed line in Figure 7(A)) to pass through in a position where its radial direction is aligned with the axial direction of the intermediate sleeve 6. After the lock ring 4 is placed inside the intermediate sleeve 6 by passing it through the notch 61, the lock ring 4 can be rotated within the annular circumferential groove 13 to change its position to be concentric with the intermediate sleeve 6, as shown in Figure 6(A).

[0037] Next, the temporary fixing jig 8 is attached to the intermediate sleeve 6 as shown in Figure 6(B). In this embodiment, the temporary fixing jig 8 is attached to the opening 6b on the insertion direction D1 side of the annular circumferential groove 13, more specifically on the opening 6b on the insertion direction D1 side of the intermediate sleeve 6. As shown in Figure 8, the temporary fixing jig 8 has a main body portion 80 formed to be fitted into the intermediate sleeve 6 (and by extension into the pipe body 1). The main body portion 80 is formed in a plate shape, but is not limited to this. The main body portion 80 has a shape that can be fitted into the notch portion 61 (see the dashed line in Figure 7(A)). This prevents movement of the temporary fixing jig 8 around its axis.

[0038] In this embodiment, the temporary fixing jig 8 has a protrusion 81 (first protrusion) protruding from the main body 80. The temporary fixing jig 8 also has a protrusion 82 (second protrusion) protruding from the main body 80. The protrusions 81 and 82 each protrude in the detachment direction D2 and are set in a radial position that can face the lock ring 4 assembled to the temporary fixing jig 8. The protrusions 81 and 82 are both formed in an arc shape extending along the circumferential direction, but are not limited to this. Furthermore, the temporary fixing jig 8 is formed of a resin such as Delrin, but is not limited to this.

[0039] Next, as shown in Figures 6(B) and (C), the lock ring 4, which has been expanded by elastic deformation, is assembled to the temporary fixing jig 8, and the assembly body 48 is fitted into the intermediate sleeve 6. The lock ring 4 is assembled adjacent to the temporary fixing jig 8 on the side in the detachment direction D2. The lock ring 4 can be expanded using a tool 34. Existing tools such as snap ring pliers can be used as the tool 34, and their tips are inserted into the insertion hole 42 (see Figure 2). Since this expansion operation of the lock ring 4 using the tool 34 is not performed through the opening 1b of the pipe body 1, it does not particularly reduce work efficiency.

[0040] In the temporary fixing process, as shown in Figure 9, the lock ring 4 is held in an expanded state by inserting the protruding portion 81 into the divided portion 41, whose gap has been enlarged by elastic deformation. Therefore, the expanded lock ring 4 can be held in a predetermined position using a simple temporary fixing jig 8. Furthermore, since it is only necessary to place the expanded lock ring 4 adjacent to the temporary fixing jig 8, the workability is excellent. The lock ring 4 is held in an expanded state to the extent that its inner diameter is larger than the outer diameter of the pipe body 2. The width W81 of the protruding portion 81 is equal to or greater than the gap in the divided portion 41 required to secure the inner diameter of the lock ring 4.

[0041] In this embodiment, during the temporary fixing process, as shown in Figure 9, the lock ring 4 is assembled to the temporary fixing jig 8 with the lock ring 4 resting against the protrusion 82. By resting the lock ring 4 against the protrusion 82, it can be used for positioning when assembling the lock ring 4 to the temporary fixing jig 8. In addition, the relative position of the lock ring 4 assembled to the temporary fixing jig 8 is stabilized, resulting in improved workability. Here, "resting against" means a state in which the lock ring 4 is placed so as to be in contact with the mating member (the protrusion 82 in this embodiment), or a state in which it is substantially placed with a small gap in between.

[0042] In this embodiment, the inner circumferential surface of the lock ring 4, specifically the portion facing the divided portion 41 across the center of the lock ring 4, is supported against the protruding portion 82. When assembling the enlarged lock ring 4, supported by the tool 34, to the temporary fixing jig 8 (see Figure 6(B)), supporting that portion against the protruding portion 82 determines the initial position of the lock ring 4 relative to the temporary fixing jig 8, thereby improving work efficiency. Furthermore, in this example, since the radially recessed notch 43 is supported against the protruding portion 82, displacement of the lock ring 4 along the circumferential direction relative to the temporary fixing jig 8 can be prevented.

[0043] As shown in Figure 6(C), after fitting the assembly 48 into the intermediate sleeve 6, the intermediate sleeve 6 is fitted into the casing 5 on which the packing 7 is attached. Although not shown, a notch is formed in the opening on the D2 side of the casing 5 to allow the passage of the intermediate sleeve 6 in a position where its radial direction is aligned with the axial direction of the casing 5. After positioning the intermediate sleeve 6 inside the casing 5 by passing it through the notch, the intermediate sleeve 6 can be rotated to change its position to be concentric with the casing 5, as shown in Figure 4. To allow the intermediate sleeve 6 to rotate smoothly, a lubricant may be applied between the inner surface of the packing 7 and the outer surface of the intermediate sleeve 6.

[0044] As described above, by fitting the intermediate sleeve 6 into the casing 5 and attaching the packing 3 to the intermediate sleeve 6, a pipe body 1 with the assembly 48 fitted inside is obtained as shown in Figure 4. The packing 3 may also be attached to the intermediate sleeve 6 before fitting it into the casing 5. The temporary fixing jig 8 in the assembly 48 fitted inside the pipe body 1 is positioned so as to interfere with the pipe body 2 when the pipe body 2 is inserted into the enlarged lock ring 4. In this embodiment, as shown in Figure 9, the temporary fixing jig 8 (main body 80) is positioned so as to traverse or cross the lock ring 4 in the assembly 48 viewed from the insertion direction D1.

[0045] As shown in Figures 4 and 7, an engagement portion 14 is formed inside the pipe 1, facing the insertion direction D1 of the pipe 2 for the expanded lock ring 4. The engagement portion 14 is formed by an annular wall portion that forms an opening (opening 6b of the intermediate sleeve 6) to which the temporary fixing jig 8 is attached, and protrudes toward the inner circumference. Adjacent to the engagement portion 14 (annular wall portion) on the side facing the disengagement direction D2, an allowable space 15 is formed that allows the arrangement of the expanded lock ring 4. The diameter dimension D15 of the allowable space 15 is larger than the diameter dimension D61 of the notch 61 and is set to be equal to or greater than the outer diameter of the expanded lock ring 4.

[0046] After temporarily fixing the lock ring 4 in the temporary fixing process, the tube 2 is inserted into the tube 1 as shown in Figure 5. Since the expanded lock ring 4 is held concentrically with the tube 1 inside the tube 1, the tube 2 inserted into the tube 1 is automatically inserted into the lock ring 4. The axis of the lock ring 4, which is temporarily fixed inside the tube 1, does not need to be precisely aligned with the axis of the tube 1; it is sufficient that they substantially coincide so that the tube 2 is inserted into the lock ring 4 when the tube 2 is inserted into the tube 1 in this manner.

[0047] In this embodiment, during the installation process, the lock ring 4 engages with the engaged portion 14 formed inside the pipe 1 in the insertion direction D1 of the pipe 2, and the temporary fixing jig 8 is pressed by the pipe 2 to remove it from the lock ring 4. This allows the temporary fixing jig 8 to be smoothly removed from the lock ring 4 by the insertion movement of the pipe 2, improving work efficiency. After the temporary fixing jig 8 is removed, the lock ring 4 shrinks in diameter due to the restoration of its elastic deformation and is attached to the outer surface of the pipe 2. After confirming that the lock ring 4 is fitted into the annular groove 21, the temporary fixing jig 8 is retrieved, and the expansion joint 10 shown in Figure 1 is obtained.

[0048] [Temporary fixing structure for the lock ring] As it has already been shown in the assembly method description, the temporary fixing structure of the lock ring 4 will be described only briefly. As shown in Figure 4, in the temporary fixing structure of this embodiment, the assembly 48, which is made by assembling the lock ring 4, which has been expanded in diameter by elastic deformation, to the temporary fixing jig 8, is fitted inside the pipe 1, and the expanded lock ring 4 is held in a position concentric with the pipe 1. Furthermore, as shown in Figure 5, when the pipe 2 is inserted into the expanded lock ring 4, the temporary fixing jig 8 is removed from the lock ring 4 by the insertion movement of the pipe 2, and the lock ring 4 is attached to the outer surface of the pipe 2.

[0049] As shown in Figures 4 and 9, in this embodiment, the temporary fixing structure holds the lock ring 4 in an expanded state by inserting the protruding portion 81 into the divided portion 41, which has a larger gap due to elastic deformation. The lock ring 4 is also assembled to the temporary fixing jig 8 with the protruding portion 82 in contact with it. Inside the pipe body 1, an engaging portion 14 is formed that faces the insertion direction D1 of the pipe body 2 for the expanded lock ring 4. Therefore, with the lock ring 4 engaged with the engaging portion 14 in the insertion direction D1 of the pipe body 2, the temporary fixing jig 8 can be pressed by the pipe body 2 and removed from the lock ring 4.

[0050] [Other embodiments] A modified example of the temporary fixing jig will be described with reference to Figures 10 and 11. The temporary fixing jig 9 shown in Figure 10 can be constructed in the same way as the temporary fixing jig 8 described above, except for the configuration described below. Therefore, the explanation of the common points will be omitted, and the differences will be explained mainly. The temporary fixing jig 9 comprises a main body portion 90 configured to be fitted inside the pipe 1, and protrusions 91 and 92 protruding from the main body portion 90. These have the same functions as the main body portion 80, protrusions 81 and 82 of the temporary fixing jig 8. The temporary fixing jig 9 is made of metal such as steel, but is not limited to this.

[0051] When the pipe body 1 (or its intermediate sleeve 6) is formed from casting, its dimensions, such as its inner diameter, tend to vary considerably. This can cause the temporary fixing jig 9 (or assembly) fitted inside the pipe body 1 to wobble or fall out of its temporarily fixed position. Taking this into consideration, the temporary fixing jig 9 is configured to allow adjustment of its length along the radial direction (vertical direction in Figure 10). This configuration allows for stabilization of the temporary fixing jig 9 (or assembly) fitted inside the pipe body 1 by adjusting its length to match the dimensions of the pipe body 1, thereby further improving work efficiency.

[0052] The temporary fixing jig 9 comprises a turnbuckle 93 as a length adjustment member and a pair of support parts 94a and 94b that support the turnbuckle 93. The main body 90 is composed of a plurality of segmented pieces, including a segmented piece 90a on which the support part 94a is formed and a segmented piece 90b on which the support part 94b is formed. As shown in Figure 11, complementary interlocking protrusions and recesses are provided between the segmented pieces 90a and 90b, and are configured to slide relative to each other along the radial direction. These protrusions and recesses are composed of a recess 95 formed in the segmented piece 90a and a protrusion 96 formed in the segmented piece 90b, but the relationship between these protrusions and recesses may be reversed.

[0053] Furthermore, this temporary fixing jig 9 is equipped with an elastic member 97 attached to its outer circumference. By interposing the elastic member 97 between the pipe 1 and the temporary fixing jig 9, the temporary fixing jig 9 can be fitted inside the pipe 1 in a fitted state. The elastic member 97 is made of rubber such as ethylene propylene rubber (EPDM). The elastic member 97 may also be made of a sponge material made by foaming rubber or synthetic resin. A mounting groove 98 for attaching the elastic member 97 is formed on the outer circumference of the main body 90. It is also possible to apply only one of the length adjustment mechanism and the elastic member 97 as described above.

[0054] In the above-described embodiment, an example was shown in which the pipe body 1 (or its casing 5) has a socket extending in the axial direction. However, the invention is not limited to this, and the pipe body 1 may also be of a type having a flange 16 as shown in Figure 12. Even in such a type, it is possible to attach the lock ring 4 to the outer surface of the pipe body 2 according to the procedure described above. However, when the pipe body 1 has a socket extending in the axial direction, the effect of improving the workability of attaching the lock ring 4 is particularly significant. As previously mentioned, when the pipe body 1 has such a socket, various inconveniences occur, such as the tool 35 not being able to reach the lock ring 4 (see Figure 3), which tends to worsen workability.

[0055] In the embodiments described above, when performing the temporary fixing and mounting processes, the axis of the pipe body 1 is typically oriented horizontally. However, it is not limited to this, and for example, the axis of the pipe body 1 may be oriented vertically so that the opening 1a faces upward. If the pipe body 1 has a small diameter, it is not very heavy, so it is not difficult to work in such a vertical position. In addition, the engagement portion 14 is formed inside the pipe body 1, which prevents the assembly 48 from falling off from the temporarily fixed position.

[0056] In the embodiments described above, an example of an assembly method for an expansion joint 10, which is an expansion flexible pipe joint, was illustrated. However, the expansion joints to which this disclosure applies are not limited to those having a bending function (flexible function). In addition, the pipe body 1 does not have to have a structure comprising a casing 5 and an intermediate sleeve 6 fitted thereto. Figure 13 shows an example in which this disclosure is applied to an expansion joint that does not have a bending function. This embodiment can be configured in the same way as the embodiments described above, except for the configuration described below. Therefore, the explanation of commonalities will be omitted, and the differences will be explained in detail. The same reference numerals are used for configurations that have already been described, and redundant explanations will be omitted.

[0057] Figure 13 shows the state immediately after inserting the pipe body 2 into the enlarged lock ring 4 during the installation process, and just before removing the temporary fixing jig 8 from the lock ring 4 (see Figure 5(A)). By further inserting this pipe body 2, the lock ring 4 is attached to the outer surface of the pipe body 2, and the expansion joint is properly assembled. In the assembled expansion joint, the pipe body 1 and the pipe body 2 inserted into it are connected so as to be able to move relative to each other along the axial direction. At the ends of the pipe bodies 1 and 2 (not shown), for example, the flexible expansion joint shown in Figure 12 is provided. This allows the expansion allowance of the expansion joint to be added to the conduit between the pair of flexible expansion joints.

[0058] In Figure 13, the assembly 48 is fitted into the pipe 1 by the temporary fixing process. However, unlike the previously described embodiment, the assembly 48 is fitted without an intermediate sleeve. Therefore, the temporary fixing jig 8 needs to be positioned inside the pipe 1 from the opening 1a on the detachment direction D2 side. Although not shown, the opening 1a and the engaged portion 11 of the pipe 1 have notches that allow the lock ring 4 to pass through in a position where its radial direction is aligned with the axial direction of the pipe 1. After positioning the lock ring 4 inside the pipe 1 by passing it through these notches, the lock ring 4 can be rotated in the annular circumferential groove 13 to change its position to be concentric with the pipe 1.

[0059] While embodiments of this disclosure have been described above, the specific configurations are not limited to these embodiments. This disclosure is not limited in any way to the embodiments described above, and various improvements and modifications are possible without departing from its spirit. Furthermore, the configurations adopted in the embodiments described above can be adopted in any combination. [Explanation of Symbols]

[0060] 1. First tube 2. Second tube 4 lock rings 5. Casing 6. Intermediate sleeves 8. Temporary fixing jig 10 Expansion joints 41 Split part 48 Assembly body 61 Notch 80 Main body 81 First projection 82 Second projection D1 Insertion direction D2 Exit direction

Claims

1. A method for assembling an expansion joint, wherein a first pipe and a second pipe inserted therein are connected so as to be able to move relative to each other within a certain range along the axial direction, and a locking ring attached to the outer surface of the second pipe provides a function to prevent detachment, A temporary fixing step is to fit the assembly, which is made by attaching the lock ring, whose diameter has been expanded by elastic deformation, to a temporary fixing jig, into the first pipe body, and to hold the expanded lock ring in a concentric position with the first pipe body, A method for assembling an expansion joint, comprising the steps of: inserting the second pipe into the expanded lock ring; removing the temporary fixing jig from the lock ring by inserting and moving the second pipe; and attaching the lock ring to the outer surface of the second pipe.

2. The lock ring has a dividing portion that divides the lock ring in the circumferential direction, The temporary fixing jig has a main body portion formed to be fitted inside the first pipe body, and a first protruding portion that protrudes from the main body portion. The method for assembling an expansion joint according to claim 1, wherein in the temporary fixing step, the lock ring is held in an expanded state by inserting the first protrusion into the divided portion whose gap has been enlarged by elastic deformation.

3. The temporary fixing jig has a main body portion formed to be fitted inside the first pipe body, and a second protruding portion that protrudes from the main body portion. The method for assembling an expansion joint according to claim 1, wherein in the temporary fixing step, the lock ring is assembled to the temporary fixing jig with the second protruding portion in contact with it.

4. The assembly method for an expansion joint according to claim 1, wherein in the mounting step, the lock ring engages with the engaged portion formed inside the first pipe in the insertion direction of the second pipe, and the temporary fixing jig is pressed by the second pipe to remove it from the lock ring.

5. The first tubular body comprises a casing having a spherical inner surface and an intermediate sleeve having a spherical outer surface that is slidably fitted relative to the spherical inner surface. The method for assembling an expansion joint according to any one of claims 1 to 4, wherein in the temporary fixing step, the assembly body is fitted inside the intermediate sleeve.

6. The intermediate sleeve has a notch formed therein that allows the lock ring to pass through in a position where its radial direction is aligned with the axial direction of the intermediate sleeve. The method for assembling an expansion joint according to claim 5, wherein in the temporary fixing step, the temporary fixing jig is fitted into the notch.

7. A temporary fixing structure for assembling an expansion joint, wherein a first pipe and a second pipe inserted therein are connected so as to be able to move relative to each other within a certain range along the axial direction, and a locking ring attached to the outer surface of the second pipe provides a function to prevent detachment, The assembly, which is formed by attaching the lock ring, whose diameter has been expanded by elastic deformation, to a temporary fixing jig, is fitted inside the first pipe, and the expanded lock ring is held in a concentric position with the first pipe. A temporary fixing structure for a lock ring, characterized in that when the second pipe is inserted into the expanded lock ring, the temporary fixing jig is removed from the lock ring by the insertion and movement of the second pipe, and the lock ring is attached to the outer surface of the second pipe.

8. The lock ring has a dividing portion that divides the lock ring in the circumferential direction, The temporary fixing jig has a main body portion formed to be fitted inside the first pipe body, and a first protruding portion that protrudes from the main body portion. The temporary fixing structure for a lock ring according to claim 7, wherein the lock ring is held in an expanded diameter state by inserting the first protrusion into the divided portion, which has been widened by elastic deformation.

9. The temporary fixing jig has a main body portion formed to be fitted inside the first pipe body, and a second protruding portion that protrudes from the main body portion. The temporary fixing structure for a lock ring according to claim 7, wherein the lock ring is assembled to the temporary fixing jig with the lock ring in contact with the second protrusion.

10. The temporary fixing structure for a lock ring according to claim 7, wherein an engaging portion is formed inside the first tube, facing the insertion direction of the second tube when the lock ring is in an expanded state.

11. The first tubular body comprises a casing having a spherical inner surface and an intermediate sleeve having a spherical outer surface that is slidably fitted relative to the spherical inner surface. The assembly is fitted inside the intermediate sleeve, a temporary fixing structure for a lock ring according to any one of claims 7 to 10.

12. The intermediate sleeve has a notch formed therein that allows the lock ring to pass through in a position where its radial direction is aligned with the axial direction of the intermediate sleeve. The temporary fixing jig is fitted into the notch, the temporary fixing structure for the lock ring according to claim 11.

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