Flexible pipe fittings

Abstract

To provide a joint for a flexible pipe capable of correctly connecting.SOLUTION: A pipe joint 1 as a joint for a flexible pipe for connecting a cornice flexible pipe in which a plurality of crest portions and valley portions are alternately arranged along an axial direction includes a joint body 2 into which the flexible pipe is inserted from one end portion. The joint has inside the joint body 2, a retainer 7, a ring-shaped seal member 6, an elastic member 4 held in a compression state, and a release mechanism 5 for holding the elastic member 4 in the compression state and releasing the compression state of the elastic member 4 due to insertion of the flexible pipe. The seal member 6 slides to an entrance side of the joint body 2 due to release of the compression state of the elastic member 4, and the retainer 7 is engaged by the slide. The seal member 6 is disposed in a position where a summit of at least the first crest portion from the tip of the flexible pipe passes through the inner peripheral part of the seal member 6 at the start of release of the compression state of the elastic member 4.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a joint for a flexible pipe to which a bellows-shaped flexible pipe is connected.

Background Art

[0002] In indoor gas piping etc., a bellows-shaped flexible pipe made of metal is widely used. Also, various pipe joints for connecting this flexible pipe to a gas tap, a steel pipe, etc. are used. In recent years, a one-touch type pipe joint that can complete construction simply by inserting a flexible pipe into the pipe joint without the need for tools has also been put into practical use.

[0003] For example, a joint for a flexible pipe (hereinafter also simply referred to as a pipe joint) described in Patent Document 1 is shown in FIG. 7. As shown in FIG. 7, the pipe joint 11 includes a joint body 12 into which a flexible pipe T (see FIG. 8) is inserted from one end. Inside the joint body 12, a part of a compression nut 13, an elastic member 14 that can expand and contract in the axial direction, a release mechanism 15 that holds the elastic member 14 in a compressed state and releases its compressed state, a ring-shaped seal member 16 that adheres to the flexible pipe T, and a retainer 17 are arranged. In FIG. 7, the release mechanism 15 has a holding member 15a that holds the elastic member 14 in a compressed state and a moving member 15b.

[0004] Here, according to the pipe joint described in FIG. 7, the flexible pipe is connected by the following procedure. (1) Insert the flexible pipe straight to the depth into the inner hole of the pipe joint and connect it. Then, (2) pull the flexible pipe straight in the pulling-out direction and confirm that the pipe does not come out to complete. Also, in a configuration where the pipe joint has an indicator, the construction is completed when the constructor confirms that the indicator appears. The operation of the pipe joint accompanying the connection work of the above (1) in such construction is shown in FIG. 8. Note that FIG. 8 and FIG. 9 described later show cross-sectional views of the upper half of the pipe joint.

[0005] As shown in Figure 8, when the flexible pipe T is inserted from one end of the pipe joint 11, the tip of the flexible pipe T comes into contact with the movable member 15b (see Figure 8(a)). Furthermore, the movable member 15b moves to the rear side of the joint body 12 in response to the insertion of the flexible pipe T. Once the flexible pipe T is fully inserted, the claw portion of the retaining member 15a disengages from the inner circumferential groove of the joint body 12 as the movable member 15b moves. Consequently, the compressed state of the elastic member 14 is released (see Figure 8(b)). As a result, the elastic member 14 stretches, and the stretching force causes the sealing member 16 to slide toward the inlet side of the joint body 12. As the sealing member 16 slides, the inclined surface of the retainer 17 comes into close contact with the inclined surface of the press nut 13, and the claw portion 17a shrinks in diameter and fits into the groove of the flexible pipe T (see Figure 8(c)). Then, in the state shown in Figure 8(c), the installer performs the verification procedure described in (2) above to confirm that the pipe is not detached and that the indicator appears. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2011-52762 [Overview of the project] [Problems that the invention aims to solve]

[0007] Incidentally, in pipe joints 11, lubricant is sometimes applied to the interface between the joint body 12 and the seal member 16 in order to improve the sliding properties of the seal member 16. However, as time passes, the lubricant may leak out of the interface, weakening the lubricating effect and potentially reducing the sliding properties of the seal member 16. In such cases, as shown in Figure 8(b), even if the compressed state of the elastic member 14 is released, the seal member 16 may not slide immediately. As a result, it may take some time for the retainer 17 to engage with the flexible pipe T (i.e., until the state shown in Figure 8(c) is reached). In that case, for example, depending on the timing of the check performed by the installer as described in (2) above, the flexible pipe may be pulled before the retainer 17 engages with the flexible pipe T, potentially causing an unintended detachment.

[0008] Figure 9 shows various states in which unintended disconnection occurs. Figure 9(a) shows a state in which the flexible pipe T has been pulled out by one extra notch compared to its normal connection state (see Figure 8(c)). Normally, the sealing member 16 should be in close contact with the flexible pipe T at the vertices of the first and second notches from the tip, but in Figure 9(a), it is in close contact with the flexible pipe T only at the vertex of the first notch from the tip, which may result in insufficient sealing. Figure 9(b) shows a state in which the flexible pipe T has been pulled out by two notches compared to its normal connection state. In Figure 9(b), the sealing member 16 is not in close contact with the flexible pipe T. Even in such an insufficient connection state, the retainer 17 is engaged with the flexible pipe T, and the flexible pipe itself does not come out. Therefore, the installer may mistakenly believe that the connection has been completed correctly even though the installation has not been properly completed. As a result, this may lead to a seal failure.

[0009] This invention has been made in view of these circumstances, and aims to provide a flexible pipe joint that can make a proper connection even when the flexible pipe is pulled before the retainer engages with the flexible pipe due to a decrease in the sliding properties of the sealing member or the like. [Means for solving the problem]

[0010] The flexible pipe joint of the present invention is a flexible pipe joint for connecting a bellows-shaped flexible pipe in which a plurality of peaks and valleys are arranged alternately along the axial direction, and comprises a joint body into which a flexible pipe is inserted from one end, and inside the joint body, there is a retainer that engages with the flexible pipe, a ring-shaped sealing member that is in close contact with the flexible pipe, an elastic member that is held in a compressed state, and a release mechanism that holds the elastic member in a compressed state and releases the compressed state of the elastic member when the flexible pipe is inserted, and when the compressed state of the elastic member is released, the sealing member slides toward the inlet side of the joint body, and the retainer engages as a result of this sliding, and the sealing member is provided at a position in which at least the apex of the first peak from the tip of the flexible pipe passes through the inner circumference of the sealing member when the release of the compressed state of the elastic member begins.

[0011] In the present invention, the release mechanism includes a movable member that can move to the rear side of the joint body upon insertion of a flexible pipe, and the compressed state of the elastic member is released when the movable member moves to the rear side of the joint body. The movable member has a contact portion that the tip of the flexible pipe abuts against, and the sealing member is preferably provided such that, at the start of the release of the compressed state of the elastic member, the apex of at least the first peak from the tip of the flexible pipe is located between the sealing member and the contact portion.

[0012] Furthermore, in the present invention, it is more preferable that the release mechanism further comprises a holding member having a support portion for supporting the elastic member and a claw portion for engaging with an inner circumferential groove formed on the inner circumferential surface of the joint body, and that a movable member positioned on the inner diameter side of the holding member moves toward the rear side of the joint body, thereby releasing the engagement of the claw portion of the holding member and releasing the compressed state of the elastic member.

[0013] Furthermore, in the present invention, the sealing member may have a protrusion projecting toward the rear of the joint body at the inner diameter end of the end face facing the rear of the joint body. [Effects of the Invention]

[0014] The flexible pipe joint of the present invention, with the above configuration, allows the flexible pipe to slide correctly even if the flexible pipe is pulled before the retainer engages with the flexible pipe. At the start of the release of the compressed state of the elastic member, the slope of the peak passing through the inner circumference of the sealing member catches on the sealing member, allowing the sealing member to slide correctly and the claw portion of the retainer to be properly positioned on the flexible pipe. This ensures that the flexible pipe is connected correctly regardless of the timing of the verification work during installation. [Brief explanation of the drawing]

[0015] [Figure 1] This is a cross-sectional view of one side of one embodiment of the pipe joint according to the present invention. [Figure 2] This is a magnified section of Figure 1. [Figure 3] This is a cross-sectional view of one side of a flexible pipe. [Figure 4] Figure 1 shows the upper half of each cross-sectional view of the pipe fitting with a flexible pipe inserted. [Figure 5] This is a partially enlarged view illustrating the operation of the pipe joint according to the present invention. [Figure 6] This is a cross-sectional view of one side of the flexible pipe after installation is complete. [Figure 7] This is a cross-sectional view of one side of a conventional pipe fitting. [Figure 8] Figure 7 shows the upper half of each state in which a flexible pipe is inserted into a pipe fitting. [Figure 9] This is a cross-sectional view of one side showing an insufficient connection. [Modes for carrying out the invention]

[0016] (First Embodiment) A first embodiment of the pipe joint according to the present invention will be described based on FIG. 1. FIG. 1 is a partial cross-sectional view of the pipe joint 1, where the upper half above the central axis O of the pipe joint 1 is a cross-sectional view and the lower half is a side view. A flexible pipe T (see FIG. 3) is connected to one end (the left side in the figure) of the pipe joint 1 in FIG. 1, and other pipes, gas equipment, etc. are connected to the other end (the right side in the figure). In the present invention, the direction along the central axis O of the pipe joint 1 is referred to as the axial direction, the direction orthogonal to the central axis O in a plan view seen from the axial direction is referred to as the radial direction, and the direction that circulates around the central axis O in the plan view is referred to as the circumferential direction.

[0017] FIG. 1 shows a state before the flexible pipe T is inserted. As shown in FIG. 1, the pipe joint 1 includes a cylindrical joint body 2, a press nut 3 a part of which is inserted into the joint body 2, an elastic member 4 that is axially expandable and contractible, a release mechanism 5 that holds the elastic member 4 in a compressed state and releases the compressed state of the elastic member 4 by the insertion of the flexible pipe T, a ring-shaped seal member 6 that adheres to the flexible pipe T, a retainer 7, and a release member 8 that releases the state in which the press nut 3 is fixed to the joint body 2. In FIG. 1, the release mechanism 5 has a holding member 51 that holds the elastic member 4 in a compressed state and a moving member 52. Further, in the pipe joint 1, a refractory packing 9a, a stop ring 9b, an O-ring 9c for sealing the press nut 3 and the joint body 2, a lip packing 9d for sealing the press nut 3 and the flexible pipe T, and a selective permeability member 9e are respectively installed.

[0018] The joint body 2 has an inner hole 21 into which the flexible pipe T is inserted at one end, and a male thread portion 27 on the outer peripheral surface of the other end. The inner diameter of the inner hole 21 gradually decreases toward the other end, and a first step portion 24 and a second step portion 25 are formed. An inner peripheral groove 26 with which the claw portion 512 of the holding member 51 engages is formed between the first step portion 24 and the second step portion 25. Also, inner peripheral grooves 22 and 23 are formed on the inner peripheral surface of one end of the joint body 2.

[0019] The press nut 3 is a cylindrical metal member having a through hole. The press nut 3 abuts against the retainer 7 and has a tip with an inclined surface 31. An outer circumferential groove 32 is formed on the outer circumferential surface of the press nut 3 into which a portion of the stop ring 9b enters. An O-ring 9c and a lip packing 9d are fitted into the other grooves of the press nut 3, respectively.

[0020] In Figure 1, the elastic member 4 is a coil spring that can expand and contract in the axial direction. Before the flexible pipe T is inserted, the elastic member 4 is held in a compressed state inside the joint body 2 by the release mechanism 5. This release mechanism 5 will be explained using an enlarged view of Figure 2.

[0021] As shown in Figure 2, the retaining member 51 of the release mechanism 5 is a ring-shaped metal member having an L-shaped cross-section. The retaining member 51 has a support portion 511 at one end that supports the elastic member 4 and a claw portion 512 at the other end. The claw portion 512 is formed by bending the end of an arc-shaped plate portion 513 that extends substantially axially from the inner diameter edge of the hollow disc-shaped support portion 511 radially outward. The retaining member 51 holds the elastic member 4 in a compressed state between the support portion 511 and the first stage portion 24 of the joint body 2, and engages the claw portion 512 with an inner circumferential groove 26 formed on the inner circumferential surface of the joint body 2. Furthermore, the inner circumferential surface of the retaining member 51 is supported by a movable member 52 to prevent the engagement of the claw portion 512 from being released, thereby maintaining the compressed state of the elastic member 4.

[0022] The movable member 52 is a member that can move to the rear side of the joint body 2 after the insertion of the flexible pipe T, and is positioned on the inner diameter side of the holding member 51. The movable member 52 is made of a lightweight material such as engineering plastic, and is designed to move smoothly. The movable member 52 has a flange portion 521 that supports the holding member 51 and a contact portion 522 that extends axially from the flange portion 521 and comes into contact with the tip T3 (see Figure 3) of the flexible pipe T.

[0023] In pipe joint 1, the axial length L of the contact portion 522 of the movable member 52 is set shorter than the corresponding axial length of the movable member in conventional pipe joints. For example, in conventional pipe joints, as shown in Figure 7, the contact portion of the movable member 15b extends from the flange portion toward the inlet side of the joint body 12, and its tip is located on the inlet side of the joint body 12 than the support portion of the retaining member 15a, and is positioned to overlap the sealing member 16. In contrast, in pipe joint 1 (see Figure 2), the tip of the contact portion 522 of the movable member 52 is located on the inner side of the joint body 2 than the support portion 511 of the retaining member 51. In this case, a space is created in the axial direction between the sealing member 6 and the contact portion 522. This space is provided so that at least one or more peaks T1 (see Figure 3) of the flexible pipe T can be accommodated. The sealing member 6 is also provided so that at least one or more peaks T1 of the flexible pipe T can be accommodated in this space. In other words, the sealing member 6 is provided such that at least one ridge T1 of the flexible pipe T completely passes through the sealing member 6.

[0024] This allows the flexible pipe T to be inserted into the pipe joint 1 until its tip completely passes through the sealing member 6. As a result, as will be described later, the flexible pipe T can be inserted such that, at the start of the release of the compressed state of the elastic member 4, the apex of at least the first peak T1 from the tip T3 of the flexible pipe T is located further inside the joint body 2 than the sealing member 6.

[0025] As shown in Figure 2, the sealing member 6 comprises a sealing body 61 made of rubber material and a retaining member 62 fixed to the inlet end face of the sealing body 61 of the joint body 2. The retaining member 62 has an L-shaped cross-section and is configured to hold the fire-resistant packing 9a. The sealing body 61 has a cylindrical inner circumference 613 that is in close contact with the flexible pipe and has an inner diameter slightly smaller than the outer diameter of the ridges of the flexible pipe. The sealing body 61 has a length that can seal two ridges of the flexible pipe. As for the rubber material used for the sealing body 61, nitrile butadiene rubber (NBR) is preferred considering its gas resistance, given the need to maintain sealing performance over a long period of time.

[0026] Furthermore, the seal body 61 is in contact with the support portion 511 of the retaining member 51 at the end face 611 facing the rear side of the joint body 2. Preferably, the seal body 61 has a protrusion 612 at the inner diameter end of this end face 611 that protrudes toward the rear side of the joint body 2. In Figure 2, the protrusion 612 is formed to protrude toward the inner diameter side of the support portion 511. By forming the protrusion 612 in this way, even if the flexible pipe T is pulled during the inspection work in construction, the peak T1 of the flexible pipe T is more likely to catch on the protrusion 612. Specifically, because the retaining member 51 is located on the outer diameter side of the protrusion 612, the direction of deformation of the protrusion 612 is restricted, and the protrusion 612 deforms to shrink toward the inner diameter side, making it easier to prevent the flexible pipe T from coming loose.

[0027] Returning to Figure 1, the other components will be described. The retainer 7 is a ring-shaped member made of an elastically deformable material (e.g., engineering plastic) and has a base 73 on which an inclined surface 72 that contacts the set nut 3 is formed. The retainer 7 is divided into multiple segments by a plurality of axial grooves 74 formed in the circumferential direction at one end, and a claw portion 71 is formed on the inner diameter side of the tip of each segment. The claw portion 71 is made of a metal material (e.g., brass). In the state shown in Figure 1, the claw portion 71 has an inner diameter larger than the outer diameter of the peak T1 of the flexible pipe T, and is sized so that it does not catch on the peak T1 when the flexible pipe T is inserted.

[0028] The fire-resistant packing 9a is a component that prevents gas leakage even when the pipe joint 1 is exposed to high temperatures due to fire or other reasons. The fire-resistant packing 9a is manufactured, for example, by kneading a rubber composition obtained by mixing raw rubber, a graphite intercalation compound that expands with heat in a non-foaming state, and, if necessary, fillers, softeners, vulcanizing agents, etc., filling the rubber composition into a mold for molding, and then press-vulcanizing it. When a fire occurs, the fire-resistant packing 9a expands with heat and fills the gap between the joint body 2 and the flexible pipe T, thereby sealing the inner circumferential surface of the joint body 2 and the outer circumferential surface of the flexible pipe T. In Figure 1, the fire-resistant packing 9a has a rectangular cross-section.

[0029] The stop ring 9b is a C-shaped member formed from a wire made of a springy metal material. As shown in Figure 1, a portion of the stop ring 9b is fitted into the inner circumferential groove 22 of the joint body 2, and the remaining portion is fitted into the outer circumferential groove 31 of the press nut 3, thereby fixing the joint body 2 and the press nut 3 together. The O-ring 9c is fitted into the outer circumferential groove formed on the inlet side of the joint body 2, which is further than the outer circumferential groove 31 of the press nut 3. The O-ring 9c prevents water from entering the inside of the pipe joint 1 from the outside, providing watertightness to the pipe joint 1. The lip packing 9d is an annular member having a substantially L-shaped cross-section and is fitted into the inner circumferential groove of the press nut 3. The lip packing 9d provides a watertight seal between the outer circumferential surface of the flexible pipe T and the inner circumferential surface of the press nut 3. The selective permeable member 9e is installed in a through hole (e.g., a circular hole) that communicates with the outside air and is located opposite one end of the joint body 2 of the press nut 3. The selective permeable member 9e is a porous member that allows gas to pass through but not liquid, and is provided to allow leaked gas to pass through when gas leakage occurs from the flexible tube T, so that it can be detected by an external gas sensor or the like.

[0030] The release member 8 is a ring-shaped member having a substantially L-shaped cross-section. The end of the release member 8 on the inlet side of the joint body 2 is formed so that its cross-section tapers towards the tip. The release member 8 is mounted adjacent to the seal member 6 and so that its body is in contact with the inner circumferential surface of the joint body 2. When the seal member 6 slides due to the stretching force of the elastic member 4, the release member 8 slides together with the seal member 6 towards the inlet side of the joint body 2. This sliding causes the end of the release member 8 on the inlet side of the joint body 2 to fit between the inner circumferential groove 22 and the stop ring 9b, reducing the diameter of the stop ring 9b and releasing the state in which the press nut 3 is fixed to the joint body 2. This operation will be explained in Figure 6 below.

[0031] Next, the insertion operation of the flexible pipe T will be explained using Figures 3 and 4. First, Figure 3 shows a cross-sectional view of one side of the flexible pipe T. The flexible pipe T is a bellows-shaped metal pipe (for example, a stainless steel pipe) in which multiple peaks T1 and valleys T2 are arranged alternately along the axial direction. Typically, the tip T3 of the flexible pipe T is cut perpendicular to the axial direction at the position of the valleys T2. The flexible pipe T is inserted into the pipe joint 1 after several peaks (six peaks in Figure 3) of the outer coating resin are removed from the tip T3.

[0032] Next, Figure 4 shows upper half cross-sectional views of each state in which the flexible pipe shown in Figure 3 is inserted into the pipe fitting in Figure 1. The states shown in Figures 4(a), (b), and (c) are followed in chronological order. First, the flexible pipe T is inserted from one end of the pipe fitting 1, passing through the inner circumference of the press nut 3 and retainer 7, and the tip T3 of the flexible pipe T abuts against the contact portion 522 of the movable member 52 (see Figure 4(a)). The movable member 52 moves to the back of the fitting body 2 in response to the further insertion of the flexible pipe T. Then, as the movable member 52 moves, the claw portion 512 of the retaining member 51 disengages from the inner groove 26 of the fitting body 2. Accordingly, the release of the compressed state of the elastic member 4 begins (see Figure 4(b)). Here, in the pipe fitting 1, the start of the release of the compressed state of the elastic member 4 refers to the point in time when the engagement of the claw portion 512 of the retaining member 51 is disengaged.

[0033] As shown in Figure 4(b), the sealing member 6 is positioned so that, at the start of the release of the compressed state of the elastic member 4, the apex of the first peak T1 from the tip T3 of the flexible pipe T completely passes through the inner circumference 613 of the sealing member 6. More specifically, the sealing member 6 is positioned such that the apex of the first peak T1 from the tip T3 of the flexible pipe T is located in the axial space between the sealing member 6 and the contact portion 522. Also, in Figure 4(b), the apex of the first peak T1 from the tip T3 of the flexible pipe T is located further back on the joint body 2 than the rear end face 611 of the joint body 2 on the sealing member 6.

[0034] Then, when the release of the compressed state of the elastic member 4 begins, the elastic member 4 stretches, and the stretching force causes the sealing member 6 to slide toward the inlet side of the joint body 2, and the release member 8 moves in cooperation with it. The retainer 7 is then pushed via the release member 8, and the inclined surface 72 comes into close contact with the inclined surface of the press nut 3, and the claw portion 71 shrinks in diameter and fits into the valley portion T2 of the flexible pipe T (see Figure 4(c)). This completes the connection of the flexible pipe T. After that, the installer checks by pulling the flexible pipe T.

[0035] The verification process should ideally be performed in the state shown in Figure 4(c). However, if it is performed, for example, at the start of the release of the compressed state of the elastic member 4 in Figure 4(b), there is a risk that the flexible tube T may unintentionally come loose (see Figure 9). In particular, if the lubricant applied to the sealing member 6 has worn off, reducing the sliding properties of the sealing member 6, such loosening of the flexible tube T is a concern.

[0036] In contrast, the present invention can prevent the above-mentioned detachment. For example, Figure 5 shows the state in which the flexible pipe T is pulled by the inspection work at the start of the release of the compressed state of the elastic member 4. The dotted line in the figure shows a part of the flexible pipe T before pulling. As shown in Figure 5, the apex of the first peak T1 from the tip T3 of the flexible pipe T passes the inner circumference 613 of the seal member 6 at the start of the release of the compressed state of the elastic member 4. Therefore, even when the flexible pipe T is pulled, the inlet side slope of the joint body 2 of the peak T1 catches on the seal member 6, and this catch assists the movement of the seal member 6, making it less likely for the movement of the seal member 6 to be delayed. As a result, the claw portion 71 of the retainer 7 fits into the correct position on the flexible pipe T, preventing the flexible pipe T from coming out unintentionally. Furthermore, as described above, the formation of a protrusion 612 on the seal body 61 causes the protrusion 612 to deform to reduce in diameter upon contact with the flexible pipe T acting in the pulling direction, making it easier to prevent the flexible pipe T from coming out.

[0037] As shown in Figure 8(b), even with the configuration of a conventional pipe joint, the peaks near the tip of the flexible pipe T are in close contact with the sealing member 16 when the elastic member 14 begins to release from its compressed state, and thus can provide resistance when the flexible pipe T is pulled. However, the configuration of a conventional pipe joint has less tensile resistance than the configuration of the pipe joint of the present invention, in which at least one peak T1 completely passes through the inner circumference of the sealing member 6 when the elastic member 4 begins to release from its compressed state, making it difficult to prevent unintended detachment.

[0038] Next, as part of the installation verification process, we will explain the movement of the pipe joint when the installer pulls the flexible pipe T. Starting from the state shown in Figure 4(c), when the flexible pipe T is pulled in the pulling direction (left side of the figure), the flexible pipe T attempts to move the press nut 3 in that pulling direction via the retainer 7. At this time, since most of the stop ring 9b is located on the outer circumference groove 32 side of the press nut 3, the outer circumference groove 32 presses against the stop ring 9b, allowing the stop ring 9b to easily move from the inner circumference groove 22 to the inner circumference groove 23 located on the inlet side of the joint body 2. As a result, the state shown in Figure 6 is achieved.

[0039] In the state shown in Figure 6, the joint body 2 and the press nut 3 are mechanically connected, preventing their relative movement. Therefore, even if further pulling force is applied to the flexible pipe T, the flexible pipe T cannot be removed from the pipe joint 1, and it is determined that the installation of the flexible pipe T is complete. Also, in Figure 6, a gap is formed between the end face of the joint body 2 and the press nut 3, so that a part of the press nut 3 that was hidden inside the joint body 2 (for example, the outer surface of the small diameter portion) is exposed in that gap. In Figure 6, this part of the press nut 3 is colored, and upon completion of installation, the colored portion 33 appears at the end of the joint body 2. The pipe joint 1 can use the colored portion 33 as an indicator. By checking this indicator, it is possible to confirm that the flexible pipe T is properly connected and to determine that the installation has been completed successfully. In addition, as another form of indicator, for example, at least the outer surface of the selectively transparent member 9e may be colored in a different hue from the joint body 2 and the press nut 3, and the selectively transparent member 9e may function as an indicator. Alternatively, the pipe joint 1 may be equipped with an indicator as a separate component from the press nut 3 and the selectively transparent member 9e.

[0040] The pipe joint of the present invention is not limited to the above-described embodiment. In the above-described pipe joint 1, the apex of the first peak T1 from the tip T3 of the flexible pipe T passes through the inner circumference 613 of the sealing member 6 when the elastic member 4 begins to release from its compressed state, but the invention is not limited to this. For example, the apex of two or more peaks T1, including the first peak T1 from the tip T3 of the flexible pipe T, may pass through the inner circumference 613 of the sealing member 6.

[0041] Furthermore, although the pipe joint 1 is configured to include a release member 8 in the above-described embodiment, this release member 8 may be omitted. Also, the release mechanism 5 only needs to be a mechanism that holds the elastic member 4 in a compressed state and releases the compressed state of the elastic member 4 by inserting the flexible pipe T, and does not have to be a mechanism composed of a holding member 51 and a moving member 52.

[0042] As described above, the pipe joint of the present invention allows for the proper connection of flexible pipes regardless of the timing of the inspection work during construction, thereby contributing to the further prevention of sealing defects. [Explanation of Symbols]

[0043] 1: Pipe fittings (fittings for flexible pipes) 2: Fitting body 21: Internal bore 22: Inner circumferential groove 23: Inner circumferential groove 24: First section 25: Second Section 26: Inner circumferential groove 27: Male thread section 3: Set nut 31: Inclined surface 32: Outer perimeter groove 33: Colored part 4: Elastic member 5:Release mechanism 51: Retaining member 511: Support part 512: Nail area 513: Arc plate section 52: Movable member 521: Flange section 522: Contact part 6: Sealing material 61: Sticker body 611: End face 612: Convex part 613: Inner circumference 62: Retaining member 7: Retainer 71: Nail area 72: Inclined surface 73: Base 74: Axial groove 8: Release Member 9a: Fire-resistant packing 9b: Stop ring 9c: O-ring 9d: Lip packing 9e: Selective permeable member T: Flexible pipe T1: Yamabe T2: Tanibe T3: Tip

Claims

1. A flexible pipe joint for connecting bellows-shaped flexible pipes in which multiple peaks and valleys are arranged alternately along the axial direction, The flexible pipe fitting comprises a fitting body into which the flexible pipe is inserted from one end, and inside the fitting body, there is a retainer that engages with the flexible pipe, a ring-shaped sealing member that is in close contact with the flexible pipe, an elastic member held in a compressed state, and a release mechanism that holds the elastic member in a compressed state and releases the compressed state of the elastic member when the flexible pipe is inserted, and when the compressed state of the elastic member is released, the sealing member slides toward the inlet side of the fitting body, and the retainer engages as a result of this sliding. The sealing member is positioned such that, at the start of the release of the compressed state of the elastic member, at least one peak from the tip of the flexible tube passes through the inner circumference of the sealing member. The sealing member has a projection on the inner diameter side end of the end face facing the rear of the joint body that protrudes toward the rear of the joint body, and the projection is provided so as to catch on the ridge of the flexible pipe when the flexible pipe is pulled out after the elastic member begins to release from its compressed state.

2. The release mechanism includes a movable member that can move to the rear side of the joint body upon insertion of the flexible pipe, and the compression state of the elastic member is released when the movable member moves to the rear side of the joint body. The movable member has a contact portion against which the tip of the flexible pipe abuts, and the sealing member is provided such that, when the release of the compressed state of the elastic member begins, at least one peak from the tip of the flexible pipe is located between the sealing member and the contact portion, characterized in that the flexible pipe joint is as described in claim 1.

3. The release mechanism further comprises a retaining member having a support portion for supporting the elastic member and a claw portion for engaging with an inner circumferential groove formed on the inner circumferential surface of the joint body, wherein the movable member, which is positioned on the inner diameter side of the retaining member, moves toward the rear side of the joint body, thereby releasing the engagement of the claw portion of the retaining member and releasing the compressed state of the elastic member, as described in claim 2.

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