Flexible Joint

Abstract

To provide a flexible joint which can be suppressed from being flexed due to the self-weight of piping or earth pressure at the time of burying, and can prevent damages on the piping and the joint when an excessive bending load is applied to the joint in ground deformation such as an earthquake.SOLUTION: A flexible joint J has a flexible mechanism FM which comprises a trunk 1 constituting a joint body, a union pipe 4 having a pipe insertion portion 4a into which piping P is inserted, and a ball sleeve 3 externally fitted to an end portion outer periphery at the trunk 1 side of the union pipe 4 and rotatably arranged in an opening 1b at the union pipe 4 side of the trunk 1. A flexibility regulation member 80 for regulating flexibility of the flexible mechanism FM is provided in an outer peripheral part of the union pipe 4.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a flexible joint. [Background technology]

[0002] BACKGROUND ART Conventionally, flexible joints (also called "swing joints") that are rotatable within a predetermined angular range at the connection portion of water pipes have been known (see, for example, Patent Documents 1 and 2).

[0003] FIG. 5 is a cross-sectional view showing a conventional flexible joint J100, illustrating a state in which the union socket 400 has rotated relative to the body 100. As shown in FIG.

[0004] Generally, as shown in Figure 5, a flexible joint J100 has a union socket 400 connected to a joint body 100 via a ball sleeve 300 so that it can move within a predetermined angular range θ100 (10 to 15 degrees). By making the flexible joint J100 movable in this way, when a load is applied to the water pipe P100, the union socket 400 rotates relative to the body 100, absorbing the load and preventing damage to the water pipe P100.

[0005] In the conventional flexible joint J100 (see Patent Document 1), a rubber cover 800 is attached to the flexible mechanism part FM100 to prevent foreign matter such as rainwater or sand from entering the flexible mechanism part FM100, which could impair flexibility or corrode parts. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Utility Model Application Publication No. 57-17588 [Patent Document 2] Japanese Patent Application Publication No. 2020-139578 Summary of the Invention [Problem to be solved by the invention]

[0007] Fig. 6A is a diagram showing a conventional flexible joint J100, and is a plan view showing the flexible joint J100 buried in a state where it has rotated left and right and up and down due to the weight, vibration, etc. of the water pipe P100. Fig. 6B is a diagram showing the conventional flexible joint J100, and is a front view showing the flexible joint J100 buried in a state where it has rotated left and right and up and down due to the weight, vibration, etc. of the water pipe P100. Fig. 7A is a diagram showing the conventional flexible joint J100, and is a plan view showing a state where the flexible joint J100 has rotated left and right and up and down due to the weight, vibration, etc. of the water pipe P100, and an additional load F200 is applied in the rotating direction due to a major earthquake, etc. Figure 7B is a diagram showing a conventional flexible joint J100, and is a front view showing the state when the flexible joint J100 has rotated left and right or up and down due to the weight or vibration of the water pipe P100, and an additional load F200 is applied in the direction of rotation due to a major earthquake or the like.

[0008] However, the flexible joints of Patent Document 1 and the flexible joint J100 shown in Figures 6A and 6B have cover 800 made of rubber and have low strength, so there is a risk that they may tilt during installation due to the weight of the water pipe P100 or the load F100 caused by earth pressure when buried.

[0009] If an additional load F200 is applied to the side of the flexible joint J100 that is moving due to a major earthquake or the like, there will be no room for flexibility, as shown in Figures 7A and 7B, and the water diverter WF or the flexible joint J100 may be deformed or damaged.

[0010] Furthermore, the flexible joint described in Patent Document 2 has a small flexibility angle (swing angle) of the joint pipe (2) of ±8 degrees, so there is a risk that it may not be able to exhibit sufficient flexibility when a load is applied to the piping or flexible joint during ground movement such as an earthquake.

[0011] The present invention aims to provide a flexible joint that can suppress bending due to the weight of the pipe or earth pressure when buried, and that can prevent damage to the pipe or joint when an excessive bending load is applied to the joint during ground movement such as an earthquake. [Means for solving the problem]

[0012] In order to solve the above-mentioned problems, the present invention provides a flexible coupling having a flexible mechanism comprising a body constituting a coupling body, a union pipe having a pipe insertion portion into which a pipe is inserted, and a ball sleeve fitted onto the outer periphery of the end portion of the union pipe on the body side and rotatably arranged within an opening portion of the body on the union pipe side, and the outer periphery of the union pipe has a flexibility restricting member that restricts the flexibility of the flexible mechanism. The flexibility restricting member is a cylindrical flexibility restricting cover loosely fitted to the outer periphery of the union pipe, and is interposed between a tool engaging portion formed on the outer periphery of the union pipe and an open end portion of the body on the union pipe side. . [Effects of the Invention]

[0013] According to the present invention, a flexible joint can be provided that can suppress bending due to the weight of the pipe or earth pressure when buried, and can prevent damage to the pipe or joint when excessive bending load is applied to the joint during ground movement such as an earthquake. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a front view, partially in section, showing an example of a flexible joint according to an embodiment of the present invention. [Figure 2] 10 is a cross-sectional view showing the state of the flexible joint when the union pipe rotates relative to the body, deforming or damaging the flexibility restraining cover. FIG. [Figure 3A] FIG. 10 is a plan view showing the state of the embedded flexible joint. [Figure 3B] FIG. 10 is a front view showing the state of the embedded flexible joint. [Figure 4A] FIG. 1 is a plan view showing the state when a large bending load is applied to an embedded flexible joint due to a major earthquake or the like. [Figure 4B] FIG. 1 is a front view showing the state when a large bending load is applied to an embedded flexible joint due to a major earthquake or the like. [Figure 5] FIG. 10 is a cross-sectional view showing a conventional flexible joint, illustrating a state in which the union pipe has rotated relative to the body. [Figure 6A] FIG. 1 is a plan view showing a conventional flexible joint that is buried in a state where it rotates left and right and up and down due to the weight, vibration, etc. of the water pipe. [Figure 6B] FIG. 1 is a front view showing a conventional flexible joint that is buried in a state where it rotates left and right and up and down due to the weight, vibration, etc. of the water pipe. [Figure 7A] This is a diagram showing a conventional flexible joint, and is a plan view showing the state when a flexible joint that has rotated left and right or up and down due to the weight or vibration of the water pipe is subjected to additional load in the rotating direction due to a major earthquake or the like. [Figure 7B] This is a front view of a conventional flexible joint, showing the state when a large earthquake or other event causes the flexible joint to rotate left and right or up and down due to the weight or vibration of the water pipe, and an additional load is applied in the direction of rotation. DETAILED DESCRIPTION OF THE INVENTION

[0015] A flexible joint J according to an embodiment of the present invention will be described with reference to FIGS. 1 to 4B. 1 will be referred to as the front (one side), and the cap nut 11 side will be referred to as the rear (the other side). Components with the same configuration will be given the same reference numerals, and their description will be omitted.

[0016] <Flexible joint> 1 and 2, the flexible joint J is a pipe joint for rotatably connecting, for example, water pipes P. The flexible joint J is configured to include a flexibility mechanism FM that rotatably connects a union pipe 4 to a body 1, a flexibility restraining cover 8, an incore 9, a ring 10, a cap nut 11, and a gasket 12. In the event of an earthquake or uneven ground subsidence, the flexible joint J follows the displacement that occurs in the flexibility mechanism FM that flexibly connects the pipes together by rotating the ball sleeve 3, and has the function of maintaining the flow function by preventing damage to the joint and the pipe P and water leakage.

[0017] The flexible joint J according to the embodiment of the present invention is not limited to use as a joint for a pipe P for supplying a liquid such as tap water, but can be used for connecting a fluid pipeline, including cases where a gas seal is required. Hereinafter, an example of the flexible joint J according to the present invention will be described taking the case of connecting a water pipe P as an example.

[0018] <Piping> As shown in FIG. 1 , the piping P is a pipe connected by a flexible joint J. The piping P is, for example, a resin water supply pipe such as a high-density polyethylene pipe for water supply (Japan Polyethylene Pipe System Association standard: JP K 001, 2, material used: PE100), which has excellent earthquake resistance and long-term hydrostatic strength. An incore 9 is press-fitted into the open end (front end) on the connection side of the piping P. The incore 9 and the end of the piping P on the flexible joint J side are inserted into the pipe insertion portion 4a of the union pipe 4.

[0019] The piping P is not limited to resin piping such as high-density polyethylene pipes for water supply, polyethylene pipes for water supply, double-layer polyethylene pipes for water supply, etc. The piping P may be other pipes such as, for example, aluminum triple-layer pipes in which the inside and outside of an aluminum pipe are coated with resin or the like.

[0020] <Incore> As shown in Figures 1 and 2, the inner core 9 is a member that is inserted and pushed into one axial side of the pipe P. By being pushed into one axial side of the pipe P, the inner core 9 maintains the front end of the pipe P in a tapered, expanded diameter state and reinforces the pipe P from the inside, preventing the pipe P from being deformed by reducing its diameter. The inner core 9 is formed, for example, from a cylindrical metal member. The inner core 9 has a tapered outer circumferential surface 9a, an annular uneven portion 9b, and a flange portion 9c.

[0021] The tapered outer peripheral surface 9a is a tapered portion for expanding the diameter of one axial side of the pipe P when the in-core 9 is press-fitted into one axial side (front end) of the pipe P. The tapered outer peripheral surface 9a is formed so as to expand in diameter from the rear end of the in-core 9 to the front end side.

[0022] The annular uneven portion 9b is a plurality of annular protrusions for fixing the in-core 9 to the pipe P by biting into the inner peripheral surface of the pipe P. The annular uneven portion 9b is made up of protrusions that are formed on the tapered outer peripheral surface 9a and have a substantially triangular shape in cross section.

[0023] The flange portion 9c is an annular flange portion formed at one axial end portion of the in-core 9. The flange portion 9c is disposed in contact with the front end surface of the pipe P.

[0024] <Flexible mechanism> As shown in FIGS. 1 and 2, the flexible mechanism FM includes a body 1, a cap 2, a ball sleeve 3, a union pipe 4, O-rings 5 and 6, and a stopper ring .

[0025] <Torso> As shown in Figures 1 and 2, the body 1 is a cylindrical fitting body extending in the axial direction. The body 1 is made of a metal casting such as a copper alloy. The body 1 is formed with a water passage hole 1a, an opening 1b, a female threaded portion 1d, an inner curved surface 1e, an O-ring mounting groove 1f, a cap mounting portion 1g, and a gasket mounting portion 1h. The body 1 is formed with a water passage hole 1a through which tap water flows from the front to the rear along the axial center line. The inner peripheral surface of the water passage hole 1a is formed with a female threaded portion 1d.

[0026] The female thread portion 1d is a threaded portion for connecting the body 1 of the flexible joint J to a saddle-equipped branch valve WF (see Figures 3A and 3B) to which the water distribution pipe P2 is connected, or the like. A gasket installation portion 1h for installing a gasket 12 is formed on the inner peripheral surface at the rear of the female thread portion 1d, protruding in the axial direction. An opening 1b for installing a ball sleeve 3 is formed on the inner peripheral surface at the rear of the gasket installation portion 1h.

[0027] On the inner peripheral surface of the opening 1b, a rotation restricting portion 1i, an inner curved surface 1e, an O-ring mounting groove 1f, and a cap mounting portion 1g are formed in this order from the front to the rear opening end 1c. As shown in FIG. 2, the rotation restricting portion 1i is provided with a ball sleeve 3. covered The rotation restricting portion 3b comes into contact with this portion to restrict rotation of the ball sleeve 3. The rotation restricting portion 1i is made of a cylindrical inner surface and is formed in front of the inner curved surface 1e inside the opening 1b.

[0028] The inner curved surface 1e is a bearing portion that rotatably supports the outer peripheral surface of the spherically shaped ball sleeve 3. The inner peripheral surface of the inner curved surface 1e is recessed in a spherical shape to match the outer peripheral surface of the ball sleeve 3.

[0029] The O-ring installation groove 1f is an annular groove in which the O-ring 5 is installed. The cap installation portion 1g is made up of a female screw that screws into a male screw portion 2a formed on the outer periphery of the cap 2. As shown in FIG. 2, the outer periphery of the body 1 is formed with, in order from the front, a small diameter portion 1j, a tapered portion 1k, and a large diameter portion 1m.

[0030] <Cap> As shown in Figures 1 and 2, the cap 2 is a drop-off prevention member that prevents the ball sleeve 3 engaged with the inner curved surface 1e of the body 1 from coming off the inner curved surface 1e. The cap 2 is made of a metal annular member (cylindrical member). The cap 2 has a male thread portion 2a on its outer circumferential surface, a concave curved surface 2c on its inner circumferential surface that rotatably engages with the outer circumferential surface of the ball sleeve 3, and a rotation restriction portion 2b at its rear end that restricts rotation of the ball sleeve 3, union pipe 4, piping P, etc., and a tool engagement groove 2d.

[0031] 2, the rotation restricting portion 2b abuts against a stopper portion 4c formed in the approximate center in the front-to-rear direction of the union pipe 4, thereby preventing the ball sleeve 3, union pipe 4, piping P, etc. from rotating by an angle of θ1 or more about the axis O1. Therefore, the cap 2 has a function to prevent the ball sleeve 3 from falling off and a rotation restricting function to restrict the rotation range of the ball sleeve 3, union pipe 4, piping P, etc. The tool engagement grooves 2d are a plurality of notched grooves into which engagement protrusions of a tool for rotating the cap 2 and screwing it onto the body 1 are engaged.

[0032] <Ball sleeve> 1 and 2, the ball sleeve 3 is a component for rotatably positioning the union pipe 4 relative to the trunk 1. The ball sleeve 3 is made of a metal casting such as a copper alloy. The ball sleeve 3 is a cylindrical spherical body fitted onto the outer periphery of the end of the union pipe 4 on the trunk 1 side (front side) and rotatably arranged within the opening 1b on the union pipe 4 side (rear side) of the trunk 1.

[0033] The outer circumferential surface of the ball sleeve 3 is provided with a spherical portion 3a having a substantially spherical shape and a groove formed at the front end of the spherical portion 3a. covered A rotation restricting portion 3b is formed. covered The rotation restricting portion 3b is formed in a cylindrical shape at the front end of the ball sleeve 3.

[0034] The inner peripheral surface of the ball sleeve 3 is formed with an O-ring installation groove 3c formed near the front side and a stopper ring installation groove 3d formed near the rear side. The O-ring installation groove 3c is an annular groove into which the O-ring 6 is engaged. The stopper ring installation groove 3d is an annular groove into which the stopper ring 7 is engaged.

[0035] <Union pipe> As shown in Figures 1 and 2, the union pipe 4 is a rotating member for rotatably connecting the pipe P to the trunk 1. The union pipe 4 is a cylindrical member extending in the axial direction. The union pipe 4 is made of a metal casting such as a copper alloy. The union pipe 4 has a ball sleeve installation section 4d at its front end onto which the ball sleeve 3 is fitted, and a pipe insertion section 4a at its rear end into which the pipe P is inserted. The union pipe 4 is configured to rotate before the ball sleeve 3 during joint installation. The member connected to the union pipe 4 is not limited to the pipe P, but may be a joint or other part other than the pipe P. The connection portion of the union pipe 4 may have any structure that allows connection to the pipe P or other members such as joints, and may have a connection structure such as a parallel male thread or a tapered female thread.

[0036] A flexibility restricting member 80 that restricts the flexibility of the flexibility mechanism FM is fitted onto the outer periphery of the union pipe 4. On the outer periphery of the union pipe 4, in order from the front, a ball sleeve installation portion 4d, a stopper portion 4c, a stopper ring installation portion 4e, a flexibility restricting cover locking portion 4f, a tool engagement portion 4b, and a male thread portion 4g are formed.

[0037] The ball sleeve installation portion 4d is where the ball sleeve 3 is fitted. The ball sleeve installation portion 4d is formed in a stepped shape so that it tapers from the rear end to the front end of the ball sleeve installation portion 4d. An O-ring 6 is fitted onto the cylindrical portion near the front of the ball sleeve installation portion 4d in an abutting state. A stopper ring installation portion 4e onto which a stopper ring 7 is fitted is formed on the cylindrical portion near the rear of the ball sleeve installation portion 4d.

[0038] The stopper portion 4c is a portion that restricts the rotation range of the ball sleeve 3, the union pipe 4, the piping P, etc., which are rotatable relative to the body 1. When the union pipe 4 rotates a predetermined flexible angle θ1 (e.g., 30 degrees) relative to the body 1, the rotation restricting portion 2b of the cap 2 comes into contact with the stopper portion 4c, thereby preventing the rotation.

[0039] The stopper ring installation portion 4e is formed of an annular groove that is U-shaped in cross section. The stopper ring installation portion 4e faces the stopper ring installation groove 3d of the ball sleeve 3, with which the outer periphery of the stopper ring 7 is engaged.

[0040] As shown in Figure 1, the flexible restraining cover engaging portion 4f is a point that engages with the inner edge portion 8c of the rear opening of the cylindrical flexible restraining cover 8 and the inner convex portion 8b that protrudes toward the axis on the front side of the inner edge portion 8c of the rear opening.

[0041] The tool engaging portion 4b is a location where a tool such as a wrench is engaged when screwing the female screw portion 11a of the socket nut 11 onto the male screw portion 4g. The tool engaging portion 4b is formed in an octagonal nut shape. The tool engaging portion 4b is formed in a large-sized portion larger than the outer diameter d1 of the ball sleeve 3. The male screw portion 4g is formed on the outer peripheral surface of the rear end portion of the union pipe 4. The male screw portion 4g is configured to tighten the ring 10 by the inner diameter expanding portion 4h to tighten the pipe P by tightening the socket nut 11 with a standard tightening force (tightening strongly).

[0042] On the inner peripheral surface closer to the rear side of the cylindrical union pipe 4, a pipe connection portion including a cylindrical pipe insertion portion 4a and an inner diameter expanding portion 4h is formed. The pipe insertion portion 4a is a location where the pipe P with the in-core 9 attached and the ring 10 fitted is inserted. That is, on one axial side (front side) of the pipe P and on one axial side (front side) of the ring 10 are inserted into the pipe insertion portion 4a. The pipe insertion portion 4a is composed of the inner wall of a cylindrical portion formed in a substantially straight shape. The inner diameter expanding portion 4h is continuously formed at a portion closer to the rear side of the pipe insertion portion 4a.

[0043] The inner diameter expanding portion 4h is a location where the ring 10 fitted on the outer peripheral surface of the pipe P is inserted and arranged. The inner diameter expanding portion 4h is formed in a tapered shape so as to expand from the rear end of the pipe insertion portion 4a toward the opening end of the inner diameter expanding portion 4h.

[0044] <O-ring and gasket> As shown in FIGS. 1 and 2, the O-rings 5, 6 and the gasket 12 are rubber sealing materials for preventing leakage of fluid (tap water) from the body 1, the ball sleeve 3 and the union pipe 4.

[0045] <Stopper ring> The stopper ring 7 is a retaining member for rotatably connecting the union pipe 4 to the ball sleeve 3. The stopper ring 7 is made of a ring member made of a metal such as phosphor bronze that is circular in cross section. The axial half of the stopper ring 7 is fitted onto the stopper ring installation portion 4e.

[0046] <Flexibility control cover> As shown in Figures 1 and 2, the flexibility restraining cover 8 is a protective cover member that protects the flexibility mechanism FM of the flexible joint J from foreign objects and the like. The flexibility restraining cover 8 (flexibility restraining member 80) is a substantially cylindrical member formed from a material such as resin or metal. The flexibility restraining cover 8 may be split or configured by engaging multiple parts so that it can be attached after the joint is assembled. The flexibility restraining cover 8 functions as a flexibility restraining member 80 that restrains the flexible joint J from bending during installation due to the weight of the pipe P or the earth pressure during burial. The flexibility restraining cover 8 ensures flexibility so that it can rotate when a large load such as an earthquake is applied. When an excessive bending load is applied to the flexible joint J during ground movement such as an earthquake, the flexibility restraining cover 8 deforms or breaks, allowing the flexible joint J to bend. Therefore, the flexibility restraining cover 8 has the function of preventing damage to the pipe P and the flexible joint J during ground movement such as an earthquake.

[0047] <Flexibility control member> 1 and 2, the flexibility restricting member 80 is a member that has the function of releasing the restriction on the flexibility of the flexibility mechanism FM by deformation or breakage. The flexibility restricting member 80 is composed of a cylindrical flexibility suppressing cover 8 loosely fitted onto the outer periphery of the union pipe 4. The flexibility restricting member 80 is interposed between a tool engaging portion 4b formed on the outer periphery of the union pipe 4 and an opening end 1c of the body 1 on the union pipe 4 side. The flexibility restricting member 80 has a flange portion 8a, an inner convex portion 8b, and a rear opening inner edge portion 8c.

[0048] The flange portion 8a is a collar portion formed with a diameter larger than the outer diameter d1 of the ball sleeve 3. The flange portion 8a is composed of an annular protrusion formed on the outer peripheral surface of the front end portion of the flexibility restricting member 80. The flange portion 8a is disposed in a state of being engaged with the rear end portion of the cap 2. The inner protrusion 8b and the rear opening inner edge 8c are portions that engage with the flexibility restraining cover locking portion 4f to support the rear end portion of the flexibility restraining cover 8. The inner protrusion 8b is an annular protrusion formed on the inner circumferential surface of the flexibility restraining member 80 near the rear end portion. The rear opening inner edge portion 8c is formed by the inner peripheral surface of the flexible restricting member 80 formed in a cylindrical shape near the rear end portion thereof.

[0049] <Cap nut> 1 and 2, the cap nut 11 is a nut that is screwed onto the male thread portion 4g formed on the outer peripheral surface of the other axial side of the union pipe 4 so as to cover the ring 10. The cap nut 11 has a female thread portion 11a and a contracted inclined surface 11b. The female thread portion 11a of the cap nut 11 is screwed onto the male thread portion 4g of the union pipe 4 that is arranged to enclose the ring 10, and the cap nut 11 is provided to tighten the ring 10 so as to seal and prevent the pipe P and the union pipe 4 from coming loose.

[0050] When the cap nut 11 is tightened, the contracting inclined surface 11b is in contact with the diameter-reducing tapered surface 10e formed at the rear end of the ring 10. This contracting inclined surface 11b is tapered on the inner surface of the cap nut 11 so that the diameter gradually increases in the tightening direction (forward). When the cap nut 11 is tightened and displaced in the axial direction, the contracting inclined surface 11b presses against the diameter-reducing tapered surface 10e of the ring 10, tightening it in the insertion direction of the piping P.

[0051] <Ring> As shown in Figure 1 or 2, ring 10 is a cylindrical body for preventing slippage of a pipe joint that is fitted onto the outer peripheral surface of a pipe P near one axial side. Ring 10 is made of a cylindrical member made of resin such as polyacetal (POM). Ring 10 has an inclined portion 10a, an outer diameter portion 10b, a biting portion 10c, a notched groove 10d, and a diameter-reducing tapered surface 10e.

[0052] When the cap nut 11 is screwed in, the ring 10 is pushed by the inner expanded diameter portion 4h formed on the inside of the union pipe 4, and the inner surface of the body side of the ring 10 and the biting portion 10c bite into the outer surface of the piping P.

[0053] As shown in FIG. 2, the inclined portion 10a is a portion formed by extending an outer diameter at an incline from the outer peripheral edge of the barrel-side end face of the ring 10 toward the other axial side.

[0054] Therefore, when the cap nut 11 of the ring 10 is tightened with a standard tightening force, the inner expanded diameter portion 4h is in close contact with the outer peripheral surface of the inclined portion 10a, thereby preventing water leakage.

[0055] As shown in FIG. 2, the outer diameter portion 10b is connected to the other axial side of the inclined portion 10a, and the outer diameter is formed toward the other axial side.

[0056] The inner peripheral surface of the body side of the ring 10 has a biting portion 10c that bites into the outer peripheral surface of the pipe P when the female thread portion 11a of the cap nut 11 is screwed onto the male thread portion 4g of the union pipe 4 and the pipe P is tightened.

[0057] The biting portion 10c is a portion that bites into the outer peripheral surface of the pipe P, the diameter of which has been expanded by the incore 9, when the cap nut 11 is tightened, and fixes the ring 10 to the outer peripheral surface of the pipe P. The biting portion 10c is formed at the tip (open end) of the inner peripheral surface of the ring 10. Therefore, when an attempt is made to pull the pipe P rearward to remove it, the biting portion 10c of the ring 10 further bites into the outer peripheral surface of the pipe P, preventing the pipe P from coming off the flexible joint J.

[0058] 1 and 2, the notched grooves 10d are slits formed by cutting from the rear end of the ring 10 toward the front end. For example, four notched grooves 10d are formed at equally spaced positions around the circumference of the ring 10.

[0059] The reduced diameter tapered surface 10e is a pressing surface that is gradually pressed in the tightening direction by the contracting inclined surface 11b at the rear end of the cap nut 11, which is arranged opposite the reduced diameter tapered surface 10e, when the cap nut 11 is tightened.

[0060] [Effect] The flexible joint J according to this embodiment is basically configured as described above, and its functions and effects will now be described with reference to FIGS. 1 to 4B.

[0061] As shown in Figure 1, Figure 3A or Figure 3B, under normal circumstances, the axis O2 of the body 1 of the flexible joint J and the axis O1 of the ball sleeve 3, flexibility restraining cover 8, union pipe 4, cap nut 11 and piping P are buried in a straight state, aligned with one another. The flexibility mechanism FM of the flexible joint J shown in Figure 1 is restrained from bending by the flexibility restraining cover 8 interposed between the body 1 of the flexible joint J and the union pipe 4, so it does not bend due to the weight of the piping P or the earth pressure when buried, and the straight state is maintained.

[0062] As shown in Figure 2, when a large bending load F (see Figure 4A or 4B) is applied to the buried flexible joint J and pipe P due to a major earthquake or the like, the load F causes the ball sleeve 3, union pipe 4, ring 10, cap nut 11, inner core 9, and pipe P to rotate around the axis O1 relative to the body 1.

[0063] As shown in Fig. 1, the flexible restraining cover 8 is interposed and supported between the body 1 of the flexible joint J and the flexible union pipe 4. Therefore, as shown in Fig. 2, 4A or 4B, when a large bending load F is applied to the pipe P, the flexible restraining cover 8 is pushed outward by the union pipe 4 and ball sleeve 3 which rotate together with the pipe P around the axis O1, causing the flexible restraining cover 8 to deform and break.

[0064] When the ball sleeve 3, union pipe 4, ring 10, cap nut 11, incore 9, and piping P rotate through an angle θ1 around the axis O1 relative to the body 1, the stopper portion 4c of the union pipe 4 comes into contact with the rotation restricting portion 2b of the cap 2, thereby stopping the rotation. The angle θ1 at which the ball sleeve 3, union pipe 4, ring 10, cap nut 11, incore 9, and piping P flex relative to the body 1 is 30 degrees, which is larger than the flex angle θ100 (10 to 15 degrees) of the conventional flexible joint J100 shown in Figure 5.

[0065] In this way, when a large bending load F is applied to the piping P, the flexible joint J of the present invention deforms and breaks the flexibility restraining cover 8, causing it to flex greatly, and since the flex angle θ1 is large, it can improve earthquake resistance.

[0066] As shown in Figures 1 and 2, the present invention provides a flexible coupling J having a flexible mechanism FM, which comprises a body 1 constituting the coupling body, a union pipe 4 having a pipe insertion portion 4a into which a piping P is inserted, and a ball sleeve 3 fitted onto the outer periphery of the end of the union pipe 4 on the body 1 side and rotatably arranged within the opening 1b on the union pipe 4 side of the body 1, and the outer periphery of the union pipe 4 has a flexibility regulating member 80 that regulates the flexibility of the flexible mechanism FM.

[0067] According to this configuration, the flexible joint J of the present invention has a flexibility restricting member 80 on the outer periphery of the union pipe 4 that restricts the flexibility of the flexibility mechanism FM, thereby making it possible to suppress flexibility due to the weight of the pipe P or the earth pressure when buried. Furthermore, when an excessive bending load F is applied to the flexible joint J during ground movement such as an earthquake, the ball sleeve 3 and the union pipe 4 rotate significantly relative to the body 1, thereby preventing damage to the pipe P and the flexible joint J.

[0068] As shown in FIGS. 1 and 2, the flexible restriction member 80 is made of resin or metal.

[0069] According to this configuration, the flexible regulating member 80, which functions as a cover to protect the flexible mechanism FM from foreign matter, etc., is made of resin or metal, and therefore can prevent the flexible joint J from bending and tilting due to the weight of the piping P or the load caused by earth pressure when buried.

[0070] As shown in FIGS. 1 and 2, the flexibility restricting member 80 releases the restriction on the flexibility of the flexibility mechanism FM by being deformed or broken.

[0071] According to this configuration, when excessive bending load is applied during ground movement such as an earthquake, the flexible regulating member 80 deforms or breaks, thereby releasing the restriction on the flexibility of the flexible mechanism FM and preventing damage to the piping P and flexible joint J.

[0072] As shown in FIG. 1, the union pipe 4 has a large portion (tool engagement portion 4b) that is larger than the outer diameter d1 of the ball sleeve 3.

[0073] According to this configuration, the union pipe 4 has a tool engagement portion 4b that is larger than the outer diameter d1 of the ball sleeve 3. This allows the union pipe 4 to accommodate a wider variety of components. In this case, the large portion may have a diameter that is partially larger than the outer diameter d1 of the ball sleeve 3, and is not limited to a portion with a large overall outer diameter. Therefore, the large portion is not limited to a nut-shaped portion that engages with a tool or a hexagonal portion.

[0074] As shown in FIGS. 1 and 2, the union pipe 4 is rotatably connected to the ball sleeve 3.

[0075] According to this configuration, the union pipe 4 is rotatably connected to the ball sleeve 3, so that during piping installation, the union pipe 4 rotates relative to the ball sleeve 3, but the ball sleeve 3 does not rotate. Therefore, even if the union pipe 4 rotates, the union pipe 4 can prevent damage to the watertight portion (O-ring 5) of the ball sleeve 3, so there is no risk of water leakage from the watertight portion after the flexible joint J is flexed.

[0076] As shown in FIG. 1, the flexibility control member 80 is composed of a cylindrical flexibility control cover 8 loosely fitted onto the outer periphery of the union pipe 4, and is interposed between the tool engagement portion 4b formed on the outer periphery of the union pipe 4 and the open end 1c of the body 1 on the union pipe 4 side.

[0077] According to this configuration, the flexible restricting member 80 is interposed between the open end 1c of the body 1 on the union pipe 4 side and the tool engagement portion 4b of the union pipe 4, which rotates relative to the body 1, and therefore can prevent the union pipe 4 from rotating when subjected to a load below a predetermined level. Furthermore, when the union pipe 4 rotates relative to the body 1 when subjected to a load above a predetermined level, the union pipe 4 rotates significantly, deforming or damaging the flexible restricting member 80. Therefore, by allowing the union pipe 4 to rotate significantly relative to the body 1 compared to conventional devices, the present invention can improve the function of absorbing the load and protecting the flexible joint J from the load.

[0078] [Variations] The flexible joint J according to this embodiment has been described in detail above with reference to Figures 1 to 5, but the present invention is not limited to this and can be modified as appropriate within the scope of the present invention. [Explanation of symbols]

[0079] 1. Torso 2 Caps 3 Ball Sleeve 4 Union Pipe 4a Tube insertion part 4b Tool engagement part (large part) 8 Flexible Restraint Cover 80 Flexible control member d1 Outer diameter of ball sleeve FM flexible mechanism J Flexible joint P piping

Claims

1. a body constituting a joint body; a union pipe having a pipe insertion portion into which a pipe is inserted; a ball sleeve fitted onto the outer periphery of the end of the union pipe on the barrel side and rotatably disposed within an opening of the barrel on the union pipe side, a flexibility restricting member for restricting the flexibility of the flexible mechanism on an outer periphery of the union pipe; The flexibility restricting member is a cylindrical flexibility restricting cover loosely fitted to the outer periphery of the union pipe, and is interposed between a tool engaging portion formed on the outer periphery of the union pipe and an open end portion of the trunk on the union pipe side. Flexible joint.

2. The flexible restricting member is formed of resin or metal.

2. The flexible joint of claim 1.

3. The flexibility restricting member releases the restriction on the flexibility of the flexibility mechanism by being deformed or broken. A flexible joint according to claim 1 or claim 2.

4. The union pipe has a large portion having an outer diameter larger than the outer diameter of the ball sleeve. A flexible joint according to any one of claims 1 to 3.

5. The union pipe is configured to rotate before the ball sleeve when the joint is installed. A flexible joint according to any one of claims 1 to 4.

6. A rotation restricting portion is formed on an inner peripheral surface of the opening, and the rotation restricting portion is formed on the ball sleeve and contacts the rotation restricting portion to restrict rotation of the ball sleeve. A flexible joint according to any one of claims 1 to 5.

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