Flexible pipe joint and installation method

Abstract

To provide a joint for a flexible pipe which can be reduced in a size while preventing the come-off of the flexible pipe, and a construction method of the flexible pipe.SOLUTION: A pipe joint 1 being a joint for a flexible pipe for connecting the flexible pipe T1 having a deformation part T11 which is formed while being spread to an outside diameter side rather than a crest part at least at a part of an external periphery comprises: a push nut 3 attached to a side reverse to a tip of the flexible pipe T1 rather than the deformation part T11; a joint main body 2 into which the tip of the flexible pipe T1 is inserted together with an end part of the push nut 3; an engagement mechanism for making the push nut 3 engaged with the joint main body 2; and a ring-shaped seal member arranged in the joint main body 2, and adhering to the flexible pipe T1. The flexible pipe T1 is connected by the engagement of the push nut 3 and the joint main body 2, and in the connection state, the deformation part T11 of the flexible pipe T1 is locked to an end part of the push nut 3 at a depth side of the joint main body, thus preventing the come-off of the flexible pipe T1.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a flexible pipe joint to which a bellows-shaped flexible pipe is connected, and to a method of installing a flexible pipe to be connected to the flexible pipe joint. [Background technology]

[0002] Metal bellows-shaped flexible pipes are widely used for indoor gas piping, etc. In addition, various pipe joints are used to connect the flexible pipes to gas valves, steel pipes, etc. In recent years, one-touch pipe joints have been put into practical use, which do not require tools and can be installed by simply inserting the flexible pipe into the pipe joint.

[0003] For example, a flexible pipe joint (hereinafter simply referred to as a pipe joint) described in Patent Document 1 is shown in Figures 14 and 15. Figure 14 shows the state before the flexible pipe is inserted, and Figure 15 shows the state after the flexible pipe is connected. As shown in Figure 14, a pipe joint 11 has a joint body 12 into which a flexible pipe is inserted from one end, and within the joint body 12, a part of a press nut 13, a retainer 18, an elastic member 14 that is axially expandable and contractible, a guide member 15 that holds the elastic member 14 in a compressed state, a moving member 16, and a ring-shaped seal member 17 that comes into close contact with the outer circumferential surface of the flexible pipe are arranged.

[0004] As shown in Fig. 15, when a bellows-shaped flexible pipe T1 is inserted into this pipe joint, the engagement between the guide member 15 and the joint body 12 is released, and the compressed state of the elastic member 14 is released. Then, as the elastic member 14 expands, the seal member 17 slides and is compressed in the axial direction. This causes the seal member 17 to come into close contact with the outer circumferential surface of the flexible pipe T1. Also, as the elastic member 14 expands, the retainer 18 contracts in diameter and the claw portions 18a fit into the valleys of the flexible pipe T1. This causes the retainer 18 to catch on the outer circumferential surface of the flexible pipe T1, preventing the flexible pipe T1 from coming loose. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2011-52762 A Summary of the Invention [Problem to be solved by the invention]

[0006] As described above, conventional pipe joints use a retainer to prevent flexible pipes from coming loose. However, such pipe joints require a retainer (a retaining member) as a component, and the axial length L2 (see FIG. 14) of the pipe joint tends to be long because the retainer is accommodated. For this reason, it is believed that there is room for further improvement in terms of miniaturization of pipe joints.

[0007] The present invention has been made in consideration of the above circumstances, and has an object to provide a flexible pipe joint and a flexible pipe installation method that can prevent the flexible pipe from coming loose while achieving miniaturization. [Means for solving the problem]

[0008] 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, the flexible pipe having a deformed portion formed by expanding at least a part of its outer periphery toward the outer diameter side beyond the peaks, and the flexible pipe joint comprises a press nut that is attached on the side opposite the deformed portion to the tip of the flexible pipe, a joint body into which the tip of the flexible pipe is inserted together with the end of the press nut, an engagement mechanism that engages the press nut with the joint body, and a ring-shaped seal member that is disposed within the joint body and fits tightly to the flexible pipe, the flexible pipe being connected by the engagement of the press nut with the joint body, and in this connected state, the deformed portion of the flexible pipe is engaged with the end of the press nut on the rear side of the joint body, preventing the flexible pipe from coming loose.

[0009] In the present invention, it is preferable that the engagement mechanism has a stop ring, an inner circumferential groove formed on the inner surface of the fitting body, a retaining member that holds the stop ring in the inner circumferential groove in an expanded state, and an outer circumferential groove formed on the outer surface of the press nut, and that when the press nut attached to the flexible pipe is inserted, the retaining member is pressed and the expanded state of the stop ring is released, so that the stop ring engages across the outer circumferential groove and the inner circumferential groove.

[0010] Furthermore, in the present invention, the retaining member has a hollow disk-shaped base that is pressed by the press nut, and a cylindrical portion extending axially from the outer peripheral edge of the base, and the tip of the cylindrical portion is provided with a plurality of protrusions that are divided along the circumferential direction and bent outward, and it is more preferable that, before the press nut is inserted, the retaining member holds the stop ring in an expanded diameter state by engaging the plurality of protrusions with an engagement groove formed on the inlet side of the fitting body rather than the inner circumferential groove.

[0011] Furthermore, in the present invention, it is more preferable that an elastic member is disposed within the joint body between the sealing member and a step portion where the inner diameter of the joint body is reduced, and that the elastic member is more compressed when connected to the flexible pipe than when the press nut is inserted.

[0012] In the present invention, a claw portion may be provided on the outer surface of the joint body, and when connected to the flexible pipe, the claw portion may be engaged with the end of the press nut on the inlet side of the joint body.

[0013] In the present invention, the deformed portion may be substantially disk-shaped with at least one or more peaks having an apex extending radially outward.

[0014] The flexible pipe installation method of the present invention is a method for connecting a bellows-shaped flexible pipe having a plurality of peaks and valleys alternately arranged along the axial direction to a flexible pipe joint, the flexible pipe joint comprising a press nut, a joint body into which the tip of the flexible pipe is inserted together with an end of the press nut, an engagement mechanism for engaging the press nut with the joint body, and a ring-shaped seal member that is disposed within the joint body and comes into close contact with the flexible pipe, the installation method including a first cutting step of cutting the flexible pipe together with the outer coating resin, and a peeling step of peeling off the coating resin. the flexible pipe is connected by the engaging step, and in this connected state, the deformed portion of the flexible pipe is engaged with the end of the press nut on the rear side of the joint body, thereby preventing the flexible pipe from coming loose.

[0015] In the present invention, it is preferable that at least one of the first cutting step, the peeling step, the second cutting step, the insertion step, and the deformation step is performed by an automatic construction machine. Effect of the Invention

[0016] By configuring the flexible pipe joint of the present invention in this way, a retainer as in conventional configurations is not required, and the flexible pipe can be prevented from coming loose while also being made smaller. [Brief description of the drawings]

[0017] [Figure 1] 1 is a half-sectional view of a first embodiment of a pipe joint according to the present invention. [Diagram 2] FIG. 2 is a perspective view of the holding member of FIG. [Diagram 3] FIG. 2 is a perspective view of the joint body of FIG. 1. [Figure 4]2 is a half-sectional view of the pipe joint of FIG. 1 in a state where a flexible pipe is connected. FIG. [Diagram 5] FIG. 5 is an enlarged view of part A in FIG. [Figure 6] FIG. 4 is a half-sectional view of a second embodiment of a pipe joint according to the present invention. [Figure 7] FIG. 2 is a process diagram showing an outline of a construction method according to the present invention. [Figure 8] 1 is a schematic diagram of an automatic construction machine used in a construction method according to the present invention. [Figure 9] FIG. 2 is an explanatory diagram of the automatic construction flow of steps S1 to S3. [Figure 10] FIG. 13 is an explanatory diagram of the automatic construction flow of steps S4 to S5. [Figure 11] FIG. [Figure 12] 13A to 13C are diagrams illustrating an operation for checking the connection state of a flexible pipe. [Figure 13] FIG. 1 is an explanatory diagram of a manual construction flow of steps S1 to S3. [Figure 14] FIG. 1 is a half-sectional view of a conventional pipe joint. [Figure 15] FIG. 15 is a half-sectional view of the pipe joint of FIG. 14 in a state where a flexible pipe is connected to the pipe joint. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] (First embodiment) A first embodiment of a pipe fitting according to the present invention will be described with reference to Fig. 1. Fig. 1 is a half-side cross-sectional view of the pipe fitting, with the upper half above the central axis O of the pipe fitting 1 being a cross-sectional view and the lower half being a side view. In the present invention, the direction along the central axis O of the pipe fitting 1 is referred to as the axial direction, the direction perpendicular to the central axis O in a plan view from the axial direction is referred to as the radial direction, and the direction going around the central axis O in the plan view is referred to as the circumferential direction.

[0019] Fig. 1 shows the state before the joint body and press nut, which are the main components of a pipe joint, are engaged. The pipe joint 1 is formed by inserting a part of the press nut 3 into the joint body 2 and engaging it. The joint body 2 has an inner hole 21 at one end into which the press nut 3 and flexible pipe are inserted, and has a male thread portion 25 on the outer circumferential surface at the other end. The inner diameter of the inner hole 21 decreases in stages toward the other end.

[0020] As shown in FIG. 1, an elastic member 4, a ring-shaped seal member 5, a holding member 6, a spacer 8a, a fireproof packing 8b, and a stop ring 8c are arranged in a cylindrical joint body. A retainer 18 (see FIG. 14), which is a member for preventing the flexible pipe from coming off, is not arranged in the joint body 2. An inner circumferential groove 22 is formed on the inner circumferential surface on one end side of the joint body 2. An engagement groove 23, which is smaller in depth than the inner circumferential groove 22, is formed on the inlet side of the inner circumferential groove 22. In the state shown in FIG. 1, the stop ring 8c is accommodated in the inner circumferential groove 22, and a protrusion 621 of the holding member 6 is engaged with the engagement groove 23.

[0021] The elastic member 4 is a spring that is expandable and contractible in the axial direction. The elastic member 4 is disposed between a stepped portion 24, where the inner diameter of the joint body 2 is reduced, and the seal member 5. In FIG. 1, a hollow disk-shaped spacer 8a is interposed between the seal member 5 and the elastic member 4, so that the restoring force of the elastic member 4 is easily transmitted to the seal member 5.

[0022] The seal member 5 has a seal body 51 made of a rubber material, and a pressing member 52 fixed to the end face of the seal body 51 on the inlet side of the joint body. The pressing member 52 has an L-shaped cross section and is configured to hold the fireproof packing 8b. The seal body 51 has a cylindrical inner periphery that comes into close contact with the flexible pipe, and has an inner diameter that is slightly smaller than the outer diameter of the ridge of the flexible pipe. The seal body 51 has a length that can seal two ridges of the flexible pipe. As the rubber material used for the seal body 51, nitrile butadiene rubber (NBR) is preferable in consideration of gas resistance and the need to maintain sealing performance for a long period of time.

[0023] The fireproof packing 8b is a member for preventing gas leakage even when the pipe joint 1 is exposed to high temperatures due to fire or the like. The fireproof packing 8b is manufactured, for example, by filling a rubber composition obtained by kneading raw rubber, a graphite intercalation compound that expands thermally in an unfoamed state, and, if necessary, a filler, a softener, a vulcanizing agent, etc., into a mold, molding, and then press vulcanizing. The fireproof packing 8b expands thermally in the event of a fire and fills the gap between the joint body 2 and the flexible pipe, thereby sealing the outer circumferential surface of the flexible pipe. In FIG. 1, the fireproof packing 8b has a rectangular cross section.

[0024] The holding member 6 is a ring-shaped member made of, for example, a resin material (such as polyacetal). The holding member 6 will be described with reference to the perspective view of FIG. 2. As shown in FIG. 2, the holding member 6 has a hollow disk-shaped base 61 and a cylindrical portion 62 extending in the axial direction from the outer periphery of the base 61. The tip of the cylindrical portion 62 is provided with a plurality of protrusions 621 that are divided along the circumferential direction and bent radially outward (outward). As shown in FIG. 1, the holding member 6 is attached in the joint body with the base 61 facing the inner side of the joint body, and the base 61 abuts against the fireproof packing 8b. This base 61 is a portion that is pressed by the press nut 3 when the press nut 3 is inserted. In addition, the holding member 6 holds the stop ring 8c in the inner circumferential groove in an expanded state by engaging the plurality of protrusions 621 with the engagement groove 23. The stop ring 8c is a C-shaped member formed of a wire made of a metal material having spring properties.

[0025] An outer circumferential groove 26 is formed on the outer circumferential surface of one end side of the joint body 2, and an indicator 7 is attached to this outer circumferential groove 26. As shown in FIG. 3, the indicator 7 has a joint at one circumferential position of the ring portion 71, and is attached to the outer circumferential groove 26 by expanding the diameter. The indicator 7 also has a claw portion 72 extending from the ring portion 71 toward the inlet side of the joint body. A plurality of claw portions 72 (three in FIG. 3) are formed at approximately equal intervals in the circumferential direction. As will be described later, in the state of connection with the flexible pipe, the claw portion 72 engages with the end portion 33 (see FIG. 4) of the press nut on the inlet side of the joint body. The claw portion may be formed integrally with the joint body 2 so as to extend directly from the outer circumferential surface of the joint body 2, rather than as a separate member.

[0026] Returning to Fig. 1, the press nut 3 is a cylindrical metal member having a through hole. A part of the press nut 3 is inserted into and engaged with the inner hole 21 of the joint body 2. An outer peripheral groove 31 into which a part of the stop ring 8c enters is formed on the outer peripheral surface of the press nut 3. In addition, an O-ring 8d, a lip packing 8e, and a selectively permeable member 8f are each attached to the press nut 3.

[0027] The O-ring 8d is fitted into an outer circumferential groove formed on the inlet side of the fitting body relative to the outer circumferential groove 31 of the press nut 3. The O-ring 8d prevents water from entering the inside of the pipe fitting 1 from the outside, providing watertightness to the pipe fitting 1. The lip packing 8e 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 8e provides a watertight seal between the outer circumferential surface of the flexible pipe and the inner circumferential surface of the press nut 3.

[0028] The selectively permeable member 8f is attached to a through hole (e.g., a circular hole) that communicates with the outside air and is provided in a position facing one end side of the joint body 2 of the press nut 3. The selectively permeable member 8f is a porous member that is permeable to gas but not to liquid, and is provided to allow the leaked gas to pass through in the event of a gas leak from the flexible pipe so that the leaked gas can be detected by an external gas sensor or the like.

[0029] Here, the pipe joint 1 has an engagement mechanism that engages the press nut 3 with the joint body 2. This engagement mechanism has a stop ring 8c, a retaining member 6, an outer peripheral groove 31, and an inner peripheral groove 22. As described below, when engaging the press nut 3, the press nut 3 is attached to the flexible pipe in advance, and the press nut 3 and the flexible pipe are inserted into the joint body 2. When the press nut 3 is inserted, the projection 621 of the retaining member 6 comes out of the engagement groove 23 and is pushed into the inner side of the joint body, and the press nut 3 and the joint body 2 are engaged by the engagement mechanism, thereby connecting the flexible pipe.

[0030] 4 and 5 show the connection state of the flexible pipe. In the connection state of FIG. 4, the holding member 6 is pushed into the rear of the joint body, and the stop ring 8c is removed from the holding member 6. The stop ring 8c straddles the outer circumferential groove 31 of the press nut 3 and the inner circumferential groove 22 of the joint body 2, thereby engaging the press nut 3 and the joint body 2. Furthermore, by inserting the press nut 3, the elastic member 4 is compressed in the axial direction more than in the state before the press nut 3 is inserted (the state of FIG. 1). Then, due to the restoring force of the elastic member 4 caused by this compression, the seal body 51 is compressed and comes into close contact with the outer circumferential surface of the flexible pipe T1.

[0031] The flexible pipe T1 is a bellows-shaped metal pipe (e.g., a stainless steel pipe) in which a plurality of peaks and valleys are alternately arranged along the axial direction. In the present invention, the flexible pipe T1 has a deformed portion T11 formed by expanding at least a part of the outer circumference toward the outer diameter side from the peaks. In FIG. 4, the deformed portion T11 is composed of the fourth and fifth peaks from the tip portion T12 of the flexible pipe T1. The peaks of the peaks expand toward the outer diameter side to form the deformed portion T11 by compressing a part of the flexible pipe T1 in the axial direction so that the distance (pitch p) between the peaks of these peaks becomes shorter. The deformed portion T11 is substantially disc-shaped, and a part of it protrudes toward the outer diameter side more than the other peaks, and the protruding part functions as a stopper for the flexible pipe. The position of the peaks constituting the deformed portion is not limited to FIG. 4.

[0032] FIG. 5 is an enlarged view of part A in FIG. 4. As shown in FIG. 5, the deformed portion T11 of the flexible pipe T1 is engaged between the end 32 of the press nut 3 on the rear side of the joint body and the seal member 5. More specifically, the deformed portion T11 is engaged between a step 321 provided on the inner diameter edge of the end 32 and the pressing member 52 of the seal member 5. The step 321 is a recessed portion toward the inlet side of the joint body so that a part of the deformed portion T11 can be inserted, and is formed over the entire circumference. In this way, by sandwiching the deformed portion T11 between the press nut 3 and the components in the joint body, even if the flexible pipe T1 is operated to be pulled out, the deformed portion T11 is caught on the end 32 of the press nut 3, and the flexible pipe T1 is prevented from coming out. Therefore, a retainer as in the conventional configuration is not required. Since there is no need to provide a retainer, there is no need to provide a space for mounting the retainer in the joint body 2, so that the axial length of the pipe joint can be shortened and the pipe joint can be made smaller. This also leads to lower costs for pipe joints.

[0033] In the pipe joint according to the present invention (see FIG. 4), the axial length when the press nut and the joint body are engaged can be made shorter than in the conventional pipe joint (see FIG. 14). For example, the axial length L2 of the conventional pipe joint is about 70 mm, whereas the axial length L1 of the pipe joint according to the present invention is, for example, 60 mm or less, preferably 50 mm or less. The lower limit of the axial length L1 is, for example, 45 mm or more.

[0034] Second embodiment A second embodiment of the pipe joint according to the present invention will be described with reference to Fig. 6. The same components as those in the first embodiment described with reference to Figs. 1 to 5 are given the same reference numerals and detailed description will be omitted. Fig. 6 shows the state of connection with a flexible pipe.

[0035] The pipe joint of the first embodiment described above is configured to seal the flexible pipe at the side, whereas the pipe joint of the second embodiment is configured to seal the flexible pipe at the end face. As shown in FIG. 6, the flexible pipe T1A connected to the pipe joint 1A has a deformation portion T11A formed by the first and second crests from the tip. In this case, the deformation portion T11A may be formed by only the first crest from the tip. In addition, since the deformation portion T11A is formed at the tip of the flexible pipe, it is easier to form the deformation portion than the pipe joint of the first embodiment. In addition, the deformation portion T11A functions as a retaining portion and also contributes to sealing properties. The deformation portion T11A is in close contact with the end face of the seal member 5A on the inlet side of the joint body, thereby ensuring sealing properties.

[0036] The sealing member 5A is made of a rubber material having an L-shaped cross section, for example, and is configured to hold the fireproof packing 8b. NBR or the like is used as the rubber material. In order to improve the sealing performance, a gasket may be used as the sealing member 5A. In FIG. 6, a leaf spring is used as the elastic member 4A.

[0037] In the pipe joint 1A as well, the flexible pipe T1A is prevented from coming loose by the deformation portion T11A being locked between the press nut 3 and a component (seal member 5A) inside the joint body. In addition, since the pipe joint 1A is configured to seal at the end face, the axial length of the joint body 2A can be made even shorter than in the pipe joint of the first embodiment.

[0038] The configuration of the pipe joint according to the present invention may be either the first or second embodiment described above, but the first embodiment is preferred from the viewpoint of the reliability of the sealing property. In the case of the first embodiment, since the contact between the ridge of the flexible pipe and the inner peripheral surface of the seal body 51 generates a surface pressure to ensure the sealing property, it is not necessarily necessary to compress the seal member in the direction along the axis of the flexible pipe, and the elastic member can be omitted. On the other hand, the second embodiment is preferred from the viewpoint of the workability of the deformed portion of the flexible pipe and further miniaturization. In the case of the second embodiment, it is preferable to provide an elastic member to maintain the sealing surface pressure.

[0039] The pipe joint according to the present invention is not limited to the above-described embodiments. For example, the indicator 7 and the spacer 8a may be omitted. This allows for a further reduction in the number of parts in addition to a reduction in the number of retainers. Furthermore, the number of peaks constituting the deformation portion is not limited to two peaks, and may be one peak or more than two peaks.

[0040] Next, a construction method according to the present invention will be described.

[0041] The installation method according to the present invention is a method for connecting a flexible pipe to the above-mentioned pipe joint. This installation method includes at least six steps (S1) to (S6) shown in Fig. 7. That is, it includes (S1) a first cutting step of cutting the flexible pipe together with the outer coating resin, (S2) a peeling step of peeling off the coating resin, (S3) a second cutting step of cutting the exposed tip of the flexible pipe, (S4) an insertion step of inserting a press nut into the processed flexible pipe, (S5) a deformation step of forming a deformed portion in the flexible pipe, and (S6) an engagement step of inserting and engaging the press nut into the joint body.

[0042] Each of the above steps S1 to S5 can be performed by a manual construction flow by manual operation by a worker, or an automatic construction flow using an automatic construction machine. However, it is preferable to perform at least one of the above steps S1 to S5 using an automatic construction machine, since this can shorten the construction time and suppress the variation in construction quality depending on the worker. The automatic construction machine will be described below first.

[0043] FIG. 8 shows a perspective view of the automatic construction machine. As shown in FIG. 8, the automatic construction machine 9 has an insertion port 91 for a flexible pipe, a chuck 92 arranged around the insertion port 91 and capable of expanding and contracting, a dust box 93, a magazine 94 for storing press nuts, and a cutting blade 95 for cutting the flexible pipe. Although not shown, the automatic construction machine 9 also has a photographing means capable of photographing the cut surface and the shape of the flexible pipe, and a deformation means for plastically deforming a predetermined peak of the flexible pipe. In addition, it is preferable that the automatic construction machine is provided with measures against electric leakage and measures (such as an automatic stop function) in the event that a finger is mistakenly inserted into the insertion port 91.

[0044] The dust box 93 stores the coating resin and the cut pieces of the flexible pipe generated in steps S1 to S3. It is preferable to provide the automatic construction machine 9 with a plurality of dust boxes so that the coating resin and the flexible pipe can be stored separately. The cutting blade 95 is provided so as to be movable relative to the inserted flexible pipe. For example, the cutting blade 95 is movable in the axial and radial directions of the flexible pipe, and can be moved along the radial direction so as to approach the flexible pipe at a predetermined axial position, thereby cutting the flexible pipe.

[0045] As shown in Fig. 8, when a flexible pipe is inserted into the automatic construction machine 9 in the direction of the arrow, the diameter of the chuck 92 automatically expands and contracts according to the diameter of the flexible pipe. The diameter of the flexible pipe is not particularly limited, and is, for example, 10A to 25A. Note that, although the automatic construction machine 9 in Fig. 8 has one insertion port 91, it may have multiple insertion ports (for example, a four-port type). In that case, it may be configured such that when the insertion port is rotated, the chuck diameter changes according to the corresponding insertion port.

[0046] Each step of the automatic construction flow will be described below with reference to the drawings. Note that the pipe joint used in the description will be the pipe joint of the first embodiment described above.

[0047] (S1 process) The S1 step is a step of cutting the flexible pipe together with the outer coating resin. In the S1 step shown in Fig. 9(a), about two peaks from the tip of the flexible pipe T1 inserted in the automatic construction machine are roughly cut by the cutting blade 95. The time required for the S1 step by the automatic construction machine is about 5 seconds.

[0048] (S2 process) Step S2 is a step of peeling off the coating resin. In step S2 shown in Fig. 9(b), about 12 peaks of the coating resin are cut off by the cutting blade 95 from the cut surface cut in step S1. At this time, the radial movement of the cutting blade 95 is controlled so as not to damage the inner flexible pipe T1. The time required for step S2 by an automatic construction machine is about 5 seconds.

[0049] (S3 process) Step S3 is a step of cutting the exposed flexible pipe at the valley portion. In step S3 shown in FIG. 9(c), about 6 to 7 peaks are cut off from the cut surface cut in step S1 by the cutting blade 95. After cutting, it is preferable to photograph the cut surface produced in this step and check the cut surface by image judgment. Furthermore, it is preferable to record the confirmation result as traceability data. This allows the cut surface of the flexible pipe T1 to be managed with high accuracy. The time required for step S3 by an automatic construction machine is about 10 seconds.

[0050] (S4 process) Step S4 is a step of inserting a press nut into the processed flexible pipe. In step S4 shown in FIG. 10(a), a press nut 3 automatically supplied from a magazine is inserted into the flexible pipe T1 after step S3. The press nut 3 is inserted to the opposite side of the tip of the flexible pipe, beyond the crest that will be plastically deformed in the following step S5. After insertion, the lip packing 8e of the press nut 3 adheres closely to the outer circumferential surface of the coating resin T2.

[0051] (S5 process) The S5 step is a step of forming a deformed portion on the outer periphery of the flexible pipe on the tip side of the press nut 3 so that the flexible pipe T1 does not come off from the press nut 3. In the S5 step shown in FIG. 10(b), the flexible pipe T1 is deformed by a deformation means provided in the automatic construction machine so that the tops of the fourth and fifth peaks from the tip of the flexible pipe T1 are expanded toward the outer diameter side more than the tops of the other peaks. The periphery of the deformed portion T11 is located radially outward from the other peaks and is formed so as to be caught by the press nut 3. This provides a slip-out prevention function. After deformation, it is preferable to photograph the shape of the flexible pipe (including the deformed portion) and confirm the shape by image judgment. Furthermore, it is preferable to record the confirmation result as traceability data. The time for using the automatic construction machine in the S4 and S5 steps is about 10 seconds. Also, although not shown in Figure 10, in the case of the second embodiment of Figure 6, a deformed portion is formed by compressing a portion of the flexible tube in the axial direction so that the tops of the first and second ridges (or only the first ridge) from the tip expand toward the outer diameter.

[0052] (S6 process) Step S6 is a step of inserting the press nut attached to the flexible pipe into the joint body together with the flexible pipe to engage them. This step is performed by manual operation. As shown in FIG. 11, when the press nut 3 and the flexible pipe T1 are inserted from one end side of the pipe joint body 2, a part of the end 32 of the press nut 3 on the rear side of the joint body hits the base 61 of the holding member 6, and the holding member 6 is pushed into the rear side of the joint body. As a result, the protrusion 621 of the holding member 6 is disengaged from the engagement groove 23 of the joint body 2. When the holding member 6 is further pushed in, the expanded state of the stop ring 8c is released, so that the stop ring 8c contracts in diameter and fits into the outer circumferential groove 31 of the press nut 3. Then, the stop ring 8c straddles the inner circumferential groove 22 and the outer circumferential groove 31, so that the joint body 2 and the press nut 3 are engaged (see FIG. 4).

[0053] After step S6, a further operation may be performed to check the connection state of the flexible pipe. For example, as shown in Fig. 12, the connection state can be checked by pulling the flexible pipe connected to the pipe fitting 1 straight in the direction of the arrow and confirming that the claw portion 72 of the indicator 7 has not come loose and is in the normal position.

[0054] Although an automatic construction machine is used in steps S1 to S5 in Fig. 9 and Fig. 10, each step may be performed manually. For example, Fig. 13 shows the procedure of each step S1 to S3.

[0055] In the S1 step, a flexible pipe cutter dedicated to stainless steel is used to cut the flexible pipe together with the outer coating resin (see FIG. 13(a)). In the S2 step, a cutter dedicated to coating resin is used to peel off about 12 peaks of the coating resin (see FIG. 13(b)). In the S3 step, a flexible pipe cutter is used to cut the exposed flexible pipe at the valleys, leaving about 6 to 7 peaks (see FIG. 13(c)). The time required for each of the S1 to S3 steps by manual operation is about 40 seconds, about 30 seconds, and about 60 seconds. In addition, the S3 step requires more work skills than the other steps, and manual construction may cause deformations such as curling, loss, dents, flattening, and crest collapse in the flexible pipe after cutting. Therefore, it is preferable to carry out at least the S3 step using an automatic construction machine in order to stabilize the quality of the cut.

[0056] Although not illustrated, steps S4 and S5 can also be performed manually. Step S5 can be performed using a dedicated jig that plastically deforms a predetermined peak of the flexible pipe. [Explanation of symbols]

[0057] 1, 1A: Pipe fittings (flexible pipe fittings) 2, 2A: Fitting body 21: Inner hole 22: Inner groove 23: Engagement groove 24:Dan section 25: Male thread 26: Outer circumferential groove 3: Press nut 31: Outer circumferential groove 32: End 321:Dan section 33: End 4, 4A: Elastic member 5, 5A: Sealing material 51: Seal body 52: Pressing member 6: Retaining member 61: Base 62: Cylindrical part 621: Protrusion 7: Indicator 71: Ring section 72: Claws 8a: Spacer 8b: Fireproof packing 8c: Stop ring 8d: O-ring 8e: Lip packing 8f: Selectively permeable material 9: Automatic construction machine 91: Insertion port 92: Zipper 93: Dustbin 94: Magazine 95: Cutting blade T1, T1A: Flexible pipe T11, T11A: Deformation section T12: Tip T2: Coating resin

Claims

1. A flexible pipe joint for connecting a bellows-shaped flexible pipe having a plurality of peaks and valleys alternately arranged along an axial direction, the flexible pipe has a deformed portion formed by expanding at least a part of an outer periphery toward an outer diameter side beyond the ridge portion, The flexible pipe joint includes a press nut attached to the side opposite the tip of the flexible pipe from the deformation portion, a joint body into which the tip of the flexible pipe is inserted together with an end of the press nut, an engagement mechanism for engaging the press nut with the joint body, and a ring-shaped seal member disposed within the joint body and in close contact with the flexible pipe, The flexible pipe is connected by engaging the press nut with the joint body, and in this connected state, the deformed portion of the flexible pipe is engaged with the end of the press nut on the rear side of the joint body, so that the flexible pipe is prevented from coming off. a flexible pipe coupling having a stop ring, an inner circumferential groove formed on the inner surface of the coupling body, a retaining member that holds the stop ring in the inner circumferential groove in an expanded state, and an outer circumferential groove formed on the outer surface of the pressing nut, wherein when the pressing nut attached to the flexible pipe is inserted, the retaining member is pressed and the expanded state of the stop ring is released, so that the stop ring engages across the outer circumferential groove and the inner circumferential groove.

2. The retaining member has a hollow disk-shaped base portion pressed by the press nut, and a cylindrical portion extending in the axial direction from the outer circumferential edge of the base portion, and a plurality of protrusions are provided at the tip of the cylindrical portion, the protrusions being divided along the circumferential direction and bent outwardly, 2. The flexible pipe joint according to claim 1, characterized in that before the press nut is inserted, the retaining member holds the stop ring in an expanded diameter state by engaging the multiple protrusions with an engaging groove formed on the inlet side of the joint body relative to the inner circumferential groove.

3. An elastic member is disposed in the joint body between the seal member and a step portion where an inner diameter of the joint body is reduced, 3. A flexible pipe joint as claimed in claim 1, wherein the elastic member is more compressed when connected to the flexible pipe than when the press nut is inserted into the flexible pipe.

4. A flexible pipe joint for connecting a bellows-shaped flexible pipe having a plurality of peaks and valleys alternately arranged along an axial direction, comprising: the flexible pipe has a deformed portion formed by expanding at least a part of an outer periphery toward an outer diameter side beyond the ridge portion, The flexible pipe joint includes a press nut attached to the side opposite the tip of the flexible pipe from the deformation portion, a joint body into which the tip of the flexible pipe is inserted together with an end of the press nut, an engagement mechanism for engaging the press nut with the joint body, and a ring-shaped seal member disposed within the joint body and in close contact with the flexible pipe, The flexible pipe is connected by engaging the press nut with the joint body, and in this connected state, the deformed portion of the flexible pipe is engaged with the end of the press nut on the rear side of the joint body, so that the flexible pipe is prevented from coming off. An elastic member is disposed in the joint body between the seal member and a step portion where an inner diameter of the joint body is reduced, 13. A flexible pipe joint, comprising: a flexible pipe coupling having a first end and a second end, the first end being connected to the flexible pipe and being compressed more than ...

5. 5. A flexible pipe joint as claimed in claim 1, characterized in that a claw portion is provided on the outer surface of the joint body, and when connected to the flexible pipe, the claw portion engages with the end of the press nut on the inlet side of the joint body.

6. 6. The flexible pipe joint according to claim 1, wherein the deformation portion has a substantially disk-like shape with at least one of the crest portions having an apex extending radially outward.

7. A method for connecting a bellows-shaped flexible pipe having a plurality of peaks and valleys alternately arranged along an axial direction to a flexible pipe joint, comprising the steps of: The flexible pipe joint includes a press nut, a joint body into which the tip of the flexible pipe is inserted together with an end of the press nut, an engagement mechanism for engaging the press nut with the joint body, and a ring-shaped seal member that is disposed within the joint body and is in close contact with the flexible pipe, The installation method includes a first cutting step of cutting the flexible pipe together with the outer coating resin, a peeling step of peeling off the coating resin, a second cutting step of cutting the exposed tip of the flexible pipe at the valley portion, an insertion step of inserting the press nut into the flexible pipe, a deformation step of forming a deformed portion in which at least a part of the outer periphery expands toward the outer diameter side beyond the crest portion on the tip side of the press nut through which the flexible pipe has been inserted, and an engagement step of inserting the press nut together with the flexible pipe into the joint body and engaging them, A method for installing a flexible pipe, characterized in that the engaging process connects the flexible pipe, and in this connected state, the deformed portion of the flexible pipe is engaged with the end of the fitting body of the press nut at the rear side, thereby preventing the flexible pipe from coming loose.

8. 8. The flexible pipe installation method according to claim 7, wherein at least one of the first cutting step, the peeling step, the second cutting step, the insertion step, and the deformation step is performed by an automatic installation machine.

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