Connecting structure of resin pipe

Abstract

To provide a connecting device of resin pipes which can reduce a manufacturing cost.SOLUTION: A connecting device 5 comprises an upper split body 10, a lower split body 20, hinge means H for connecting one end parts of the split bodies 10, 20, and fastening means 30 for fastening the other end parts of the split bodies 10, 20 so as to approach each other. Fitting grooves 12, 22 are formed at internal peripheral faces of main body parts 11, 21 of the split bodies 10, 20. Since tapered faces 12a, 22a of the fitting grooves 12, 22 abut on tapered faces 1y, 2y of flange parts 1a, 2a of resin pipes 1, 2 at fastening, the flange parts 1a, 2a of the resin pipes 1, 2 abut on each other. A downward-extended engagement part 15 is provided at one end part of the main body part 11 of the upper split body 10. An engagement hole 16 is formed at the engagement part 15. An engagement protrusion 25 is provided at one end part of the main body part 21 of the lower split body 20. The hinge means H is constituted by the insertion of the engagement protrusion 25 into the engagement hole 16. The engagement hole 16 has a main hole part 16a and a relief recess 16b.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a device for connecting two plastic pipes each having a flange at one end. [Background technology]

[0002] When it is necessary to connect plastic pipes without welding at the construction site, a plastic pipe with a flange at the end is manufactured by butt welding a short pipe with a flange to the main plastic pipe at the factory. The flange has a butt joint surface at the tip that is perpendicular to the axis of the plastic pipe, and a tapered surface on the opposite side. At the construction site, a connecting device is used to connect the flanges of the two plastic pipes by butting them together.

[0003] The connection device disclosed in Patent Document 1 includes a pair of upper and lower segments, hinge means for rotatably connecting one end of the pair of segments to each other, and fastening means for tightening the other end of the pair of segments so as to bring the other end of the pair of segments closer to each other. Each of the pair of segments has a main body portion with a semicircular mating groove formed on its inner periphery. Tapered surfaces are formed on both sides of the mating groove at a taper angle equal to the tapered surfaces of the flange portions. Each of the pair of segments has a connecting portion that protrudes radially outward from one end of the main body, and a support portion that protrudes radially outward from the other end of the main body. The hinge means has a link whose opposite ends are rotatably connected to the support portions of the pair of divided bodies. The fastening means includes a shaft member provided on the support portion of the lower divided body, a den-den bolt having a ring portion that is inserted into the shaft member, and a nut that is threaded onto the den-den bolt.

[0004] To briefly explain the process of connecting plastic pipes using the above-mentioned connecting device, the pair of segments is opened, and the flanges of the two plastic pipes are placed in the mating grooves of the lower segment. Next, the upper segment is rotated in the closing direction, loosely fitting the flanges of the two plastic pipes into the mating grooves. Finally, the bolt attached to the lower segment is inserted into the slit in the support section of the upper segment, and the nut threaded onto this bolt is tightened toward the support section of the upper segment. This causes the tapered surfaces on both sides of the mating groove to come into contact with the tapered surfaces of the flanges of the two plastic pipes, and the tightening force is converted into an axial force that moves the flanges of the two plastic pipes closer together. As a result, the two plastic pipes are connected with the butt surfaces of the flanges touching each other. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5740123 Summary of the Invention [Problem to be solved by the invention]

[0006] In Patent Document 1, the hinge means that rotatably connects the pair of divided bodies includes a link, and this link is rotatably connected to the divided bodies, which increases the manufacturing costs of the connection device. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, the present invention provides a device for connecting two plastic pipes each having an annular flange portion at one end, the device comprising first and second divided bodies, hinge means for rotatably connecting one end of the first and second divided bodies to each other along a plane perpendicular to the axis of the plastic pipe, and fastening means for fastening the first and second divided bodies so as to bring the other end of the first and second divided bodies closer to each other while sandwiching the flange portions of the two plastic pipes between the first and second divided bodies, the first and second divided bodies having main bodies with fitting grooves formed on their inner circumferences in an arc shape, the fitting grooves having tapered surfaces on both sides, and when fastened by the fastening means, The tapered surface of the mating groove comes into contact with the tapered surfaces formed on the flange portions of the two plastic pipes, causing the flange portions of the two plastic pipes to butt against each other; an engaging portion extending toward the second partition is provided on the radially outer side of one circumferential end of the main body portion of the first partition, an engaging hole is formed in the engaging portion, an engaging protrusion protruding radially outward is provided on one circumferential end of the main body portion of the second partition, and the hinge means is formed by the engaging protrusion of the second partition being rotatably inserted into the engaging hole of the first partition.

[0008] According to the above configuration, the hinge means is formed by the engaging portion of the first divided body and the engaging protrusion of the second divided body, so the configuration is simplified and the manufacturing cost is low.

[0009] Preferably, the engagement hole has a main hole portion that accommodates the engagement protrusion when the first and second divided bodies are fastened by the fastening means, and has an escape recess that is connected to the main hole portion and formed on the opposite side of the second divided body. According to the above configuration, when the engaging protrusion of the second segment is inserted into the engaging hole of the first segment and the first segment is placed over the flange portion, the tip of the engaging protrusion can be received in the relief recess. This prevents interference between the engaging portion of the first segment and the engaging protrusion of the second segment without increasing the distance between the engaging hole of the first segment and the end of the main body. This allows the point of application of the tightening force of the first and second segments to be closer to the end of the main body and the plastic pipe, thereby increasing the connection strength of the plastic pipe. Furthermore, when a large tensile load or bending load is applied to the plastic pipe due to an earthquake or other event, the stress generated in the first and second segments can be kept low, preventing damage to the first and second segments.

[0010] Preferably, the other ends of the first and second division bodies are each formed with a support portion that protrudes radially outward, and the fastening means is constituted by a bolt that passes through these support portions and a nut that is screwed onto the bolt, and one of the support portions is formed with a protrusion to prevent the nut from rotating. According to the above configuration, the first and second divided bodies can be fastened together efficiently using the nuts and bolts that are prevented from rotating.

[0011] Preferably, a short cylindrical in-core is disposed on the inner periphery of one end of each of the two resin pipes. According to the above configuration, even if a large tensile load is applied to the two plastic pipes due to an earthquake or the like, and a strong radially inward force acts on the end of the plastic pipe due to the action of the tapered surfaces of the first and second divisions and the tapered surfaces of the flange portions of the plastic pipes, the in-core can prevent elastic deformation of the end of the plastic pipe, and can prevent the flange portions from separating from the first and second divisions due to this elastic deformation.

[0012] Preferably, the first and second divided bodies are made of a resin containing glass fiber. This configuration reduces the weight of the connecting device and further reduces manufacturing costs. [Effects of the Invention]

[0013] According to the present invention, the hinge means for rotatably connecting the first and second divided bodies does not require a link, and the manufacturing costs of the connection device can be reduced. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a perspective view showing a resin pipe connecting device according to a first embodiment of the present invention in a state where connection of the resin pipe has been completed, with the connecting device and the resin pipe partially cut away.

[0023] FIG. [Figure 2] 1 is a perspective view showing a pair of upper and lower divided bodies of the connection device in a separated state, in which the pair of divided bodies are each cut in half in the width direction and are viewed from different directions. FIG. [Figure 3] FIG. 2 is a cross-sectional view showing the pair of divided bodies in a separated state. [Figure 4] FIG. 4 is a side view showing the pair of divided bodies in a separated state. [Figure 5] 1A is a plan view of the upper split body, and FIG. 1B is a bottom view of the lower split body. [Figure 6] 4A and 4B are cross-sectional views sequentially showing a connecting process of a resin pipe using the connecting device, where (A) shows a state during the connecting process, and (B) shows a state after the connecting process is completed. [Figure 7] 4A and 4B are longitudinal cross-sectional views sequentially showing a connecting process of a resin pipe using the connecting device, where FIG. 4A shows a state during the connecting process, and FIG. 4B shows a state after the connecting process is completed. [Figure 8] FIG. 6 is a cross-sectional view showing an upper divided body of a connecting device according to a second embodiment of the present invention. [Figure 9] FIG. 7 is a view corresponding to FIG. 6(A) showing a connection device according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] A first embodiment of the present invention will be described below with reference to FIGS. Resin pipe structure First, referring to Figures 1 and 7, the plastic pipes 1 and 2 to be connected will be described. The plastic pipes 1 and 2 are made of a resin such as polyethylene and have annular flanges 1a and 2a at one end. The tip surfaces of the flanges 1a and 2a form mating surfaces 1x and 2x that are perpendicular to the axis L, and the surfaces on the opposite sides form tapered surfaces 1y and 2y. An annular groove 1z is formed in the mating surface 1x of the flange 1a of one of the plastic pipes 1, and an O-ring 3 is fitted into this annular groove 1z. The resin pipes 1 and 2 are manufactured by butt welding a short pipe having the flange portions 1a and 2a to a resin pipe body.

[0016] A short cylindrical incore 4 is disposed on the inner periphery of one end of each of the plastic pipes 1 and 2. The incore 4 is made of stainless steel such as SUS304, and has an annular flange 4a that protrudes radially and outward at one end. This flange 4a engages with annular recesses 1b and 2b formed on the inner periphery of the tip of each of the plastic pipes 1 and 2, thereby attaching the incore 4 to the plastic pipes 1 and 2 with its axial movement restricted. Because the flange 4a is housed in the recesses 1b and 2b, it does not interfere with the butting of the flanges 1a and 2a, which will be described later.

[0017] Configuration of the connected device Next, we will explain the connection device 5 for connecting the resin pipes 1 and 2. The connection device 5 includes a pair of upper and lower division bodies, that is, an upper division body 10 (first division body) and a lower division body 20 (second division body). The divided bodies 10, 20 are made of, for example, glass fiber reinforced resin (nylon, polypropylene, polyacetal, etc.), and have approximately semi-cylindrical main bodies 11, 21. The inner diameter of the main bodies 11, 21 is approximately equal to the outer diameter of the resin pipes 1, 2.

[0018] The main bodies 11, 21 of the segments 10, 20 have a circumferential dimension slightly shorter than that of a complete semicylinder. That is, as shown in Fig. 3, the circumferential end faces 11a, 11b of the main body 11 of the upper segment 10 are slightly set back from a plane P passing through the radial center C of the inner periphery of the main body 11 and are parallel to this plane P. Similarly, the circumferential end faces 21a, 21b of the main body 21 of the lower segment 20 are slightly set back from a plane P' passing through the radial center C' of the inner periphery of the main body 21 and are parallel to this plane P'.

[0019] The inner peripheries of the main bodies 11, 21 of the divided bodies 10, 20 are formed with mating grooves 12, 22 that extend in a substantially semicircular shape in the circumferential direction. Tapered surfaces 12a, 22a are formed on both sides of the mating grooves 12, 22. The taper angles of the tapered surfaces 12a, 22a are the same as the tapered surfaces 1y, 2y of the flanges 1a, 2a of the resin pipes 1, 2. The cross-sectional shapes of the mating grooves 12, 22 are substantially the same as the cross-sectional shapes of the flanges 1a, 2a when the butting surfaces 1x, 2x of the flanges 1a, 2a are in contact, as will be described later. The main body portions 11 and 21 are provided on their outer peripheries with recesses 13 and 23 extending in the circumferential direction.

[0020] An engaging portion 15 is provided integrally with the main body 11 at one end of the main body 11 of the upper half body 10. This engaging portion 15 has a protruding portion 15a that protrudes radially outward from one end of the main body 11, and an extending portion 15b that extends downward (toward the lower half body 20) from the tip of this protruding portion 15a, beyond the end face 11a, and perpendicular to the end face 11a.

[0021] An engagement hole 16 is formed in the engagement portion 15 of the upper half body 10. This engagement hole 16 has a main hole portion 16a formed in the extension portion 15b and penetrating in the radial direction, and an escape recess portion 16b formed in the protrusion portion 15a and connected to the main hole portion 16a. The main hole portion 16a is generally rectangular and occupies a portion between a lower surface 16x of the engagement hole 16 and an extension of the end surface 11a of the main body portion 11. This lower surface 16x serves as a load-receiving surface, as will be described later. In Fig. 4, the vertical dimension of the main hole portion 16a is indicated by the symbol Dy, and the horizontal dimension is indicated by the symbol Dx. The relief recess 16b is located above the extension plane of the end face 11a (opposite the lower division body 20) and is open only radially outward. The lateral dimension of the relief recess 16b is equal to the lateral dimension Dx of the main hole portion 16a.

[0022] An engagement protrusion 25 extending radially outward is formed integrally with the main body 21 at one end of the main body 21 of the lower half body 20. The cross section of the engagement protrusion 25 is rectangular, and its upper surface is flush with the end surface 21a of the main body 21. The vertical and horizontal dimensions of the engagement protrusion 25 are slightly shorter than the vertical dimension Dy and horizontal dimension Dx of the main hole portion 16a of the engagement hole 16 in the upper half body 10. As will be described later, the engagement protrusion 25 of the lower division body 20 is inserted into the engagement hole 16 of the upper division body 10 to form a hinge means H. This hinge means H connects the upper division body 10 to the lower division body 20 so as to be rotatable relative to each other along a plane perpendicular to the axis L of the resin pipes 1 and 2.

[0023] Support portions 18, 28 that protrude radially outward are formed integrally with the main body portions 11, 21 at the other ends of the main body portions 11, 21 of the divided body 10, 20, respectively. The lower surface of the support portion 18 is flush with the end surface 11b of the main body portion 11, and the upper surface of the support portion 28 is flush with the end surface 21b of the main body portion 21. Through holes 18a, 28a are formed in the support portions 18, 28. A pair of anti-rotation protrusions 29 are formed on the lower surface of the support portion 28, located on both sides of the through hole 28a. As shown in FIG. 6(B), fastening means 30 for fastening the support parts 18 and 28 together includes a bolt 31 and a nut 32.

[0024] Resin pipe connection process using a connecting device The process of connecting the plastic pipes 1 and 2 using the connecting device 5 will now be described. As shown in Figures 6(A) and 7(A), first, the flange portions 1a and 2a of the plastic pipes 1 and 2 are placed on the lower divided body 20 with the O-ring 3 brought close enough to lightly contact the mating surface 2x of the plastic pipe 2. The flange portions 1a and 2a are aligned with the fitting groove 22, and a portion of them is received in the fitting groove 22.

[0025] Next, the upper half body 10, while still in an inclined position, is brought closer to the lower half body 20 from the side, and the engaging protrusion 25 is inserted into the engaging hole 16 of the engaging portion 15. At this time, part of the tip of the engaging protrusion 25 comes out of the main hole portion 16a of the engaging hole 16, but can be received in the relief recess 16b, so it can be fitted deep over the flange portions 1a and 2a without interfering with the engaging portion 15.

[0026] More specifically, in the initial stage when the engaging projection 25 is inserted into the engaging hole 16 to form the hinge means H, the position where the deepest end E of the fitting groove 12 of the upper section 10 (the end opposite the hinge means H) contacts the top or its vicinity of the flange sections 1a, 2a must exceed half of the circumference of the upper half of the flange sections 1a, 2a. In other words, the end E of the upper section 10 must be located to the left of the vertical plane V passing through the centers of the flange sections 1a, 2a in FIG. 6(A) (the opposite side of the hinge means H). This is because, when the upper section 10 rotates toward the lower section 20 around the fulcrum F (the point where one end of the load-receiving surface 16x contacts the lower surface of the engaging projection 25), the upper section 10 does not experience significant resistance from the flange sections 1a, 2a.

[0027] In this embodiment, the relief recess 16b allows the tip of the engagement projection 25 to escape, so even if the distance X between the extension 15b and one end of the main body 11 is short, point E can be positioned to the left of the vertical plane V without interference. This can be understood by comparing with the third embodiment described later.

[0028] Next, by rotating the upper divisional body 10 around the fulcrum F so as to move it closer to the lower divisional body 20, the support portion 18 of the upper divisional body 10 approaches and faces the support portion 28 of the lower divisional body 20. In this state, parts of the flange portions 1a, 2a are also accommodated in the fitting groove 12 of the upper divisional body 10. In addition, the engaging protrusion 25 of the lower divisional body 20 is accommodated in the main hole portion 16a of the engaging hole 16 of the upper divisional body 10.

[0029] Next, as shown by phantom lines in FIG. 5(B), a nut 32 is fitted between the pair of anti-rotation projections 29 so as not to rotate. Then, as shown in FIG. 6(B), a bolt 31 is threaded through the through-holes 18a, 28a of the support portions 18, 28 of the segments 10, 20, threaded onto the nut 32, and turned in the tightening direction. This clamps the flanges 1a, 2a of the resin pipes 1, 2 between the lower segment 20 and the upper segment 10. This radially inward tightening force is converted into an axial force that moves the flanges 1a, 2a toward each other by the action of the tapered surfaces 12a, 22a on both sides of the fitting grooves 12, 22 and the tapered surfaces 1y, 2y of the flanges 1a, 2a. As a result, as shown in FIG. 7(B), the butting surfaces 1x, 2x of the flanges 1a, 2a come into surface contact with each other due to the elastic deformation of the O-ring 3. This completes the connection process.

[0030] Tightening the bolt 31 brings the support parts 18, 28 closer to each other, and a force acts in the direction of moving the opposite sides apart. As a result, the engagement protrusion 25 strongly hits the load-receiving surface 16x of the engagement hole 16 of the engagement part 15. This allows the lower half body 20 and the upper half body 10 to tightly fasten the flange parts 1a, 2a together.

[0031] In this embodiment, the distance X between the load-receiving surface 16x of the engagement hole 16 and the end of the main body 11 is short, and as a result, the point of application of the tightening force of the segments 10, 20 can be brought closer to the end of the main body 11, 21 and the resin pipes 1, 2, thereby increasing the connection strength of the resin pipes 1, 2. Furthermore, when a large tensile load or bending load is applied to the resin pipes 1, 2 due to an earthquake or the like, the stress generated in the segments 10, 20 can be kept low, preventing damage to the segments 10, 20.

[0032] In this embodiment, the in-core 4 is disposed on the inner periphery of the end of the plastic pipe 1, 2, so that the connection state of the plastic pipe 1, 2 can be reliably maintained even if a large tensile load acts on the plastic pipe 1, 2 during an earthquake or other disaster. Specifically, when a large tensile load is applied to the two plastic pipes 1, 2, a strong radially inward force is applied to the end of the plastic pipe 1, 2 due to the action of the tapered surfaces 12a, 22a of the segments 10, 20 and the tapered surfaces 1y, 2y of the flanges 1a, 2a of the plastic pipe 1, 2. However, the in-core 4 prevents the end of the plastic pipe 1, 2 from elastically deforming in the radially inward direction, thereby preventing the diameter of the flanges 1a, 2a from shrinking due to this elastic deformation. As a result, the flanges 1a, 2a can be prevented from coming off the connecting device 5.

[0033] Next, another embodiment of the present invention will be described with reference to the drawings. In these drawings, components corresponding to those in the first embodiment are given the same reference numerals and detailed description thereof will be omitted. Second embodiment 8, the upper surface of the engagement hole 16 is inclined, and the cross section of the relief recess 16b' is triangular. Similar to the relief recess 16b of the first embodiment, the relief recess 16b' of the second embodiment allows the tip of the engagement protrusion 25 to escape in the early stage of attachment to the flange portions 1a, 2a of the upper half body 10.

[0034] Third embodiment In the third embodiment shown in FIG. 9, the engagement hole 16' has only a main hole portion 16a and no relief recess. In this third embodiment, in order to position the end E of the upper section 10 to the left of the vertical plane V as in the first embodiment, it is necessary to increase the protrusion amount of the protruding portion 15a of the engagement portion 15 and increase the distance X between the engagement hole 16' and the end of the main body portion 11. Therefore, when fastening is complete, the point of application of the tightening force of the sections 10, 20 is farther away from the main body portions 11, 21 and the plastic pipes 1, 2 than in the first embodiment. This third embodiment can be adopted if the sections 10, 20 are made of a high-strength material.

[0035] The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the invention. [Industrial Applicability]

[0036] The present invention can be applied to a device for connecting a resin pipe having a flange portion at the end. [Explanation of symbols]

[0037] 1, 2 Resin pipe 1a, 2a flange 1x, 2x butt faces 1y, 2y tapered surface 4 Incore 5 Connecting Devices 10 Upper division body (first division body) 11 Main body 12 Fitting groove 12a Tapered surface 15 Engagement part 16,16' engagement hole 16a Main hole 16b, 16b' Relief recess 18 Support part 20 Lower divided body (second divided body) 21 Main body 22 Fitting groove 22a Tapered surface 25 Engagement protrusion 28 Support part 29 Anti-rotation protrusion 30 Fastening means 31 Bolt 32 Nut H Hinge Means

Claims

1. A device for connecting two resin pipes, each having an annular flange portion at one end, The device comprises a first and second divided body, a hinge means for connecting one end of the first and second divided body so that they can rotate along a plane perpendicular to the axis of the resin pipe, and a fastening means for tightening the other ends of the first and second divided body together so that they are close together while the first and second divided body sandwiches the flange portions of the two resin pipes. The first and second divided bodies described above each have a main body portion with a fitting groove extending in an arc shape on its inner circumference, and the fitting groove has tapered surfaces on both sides thereof. When tightened by the fastening means, the tapered surfaces of the fitting groove come into contact with the tapered surfaces formed on the flange portions of the two resin pipes, causing the flange portions of the two resin pipes to abut against each other. An engaging portion is provided on the radially outer side of one circumferential end of the main body portion of the first divided body, extending toward the second divided body, and an engaging hole is formed in the engaging portion. An engaging projection is provided at one circumferential end of the main body portion of the second divided body described above, projecting radially outward. The hinge mechanism is configured such that the engaging projection of the second divided part is rotatably inserted into the engaging hole of the first divided part. The engagement projection of the second divided body has a curved surface at the intersection of the main body side surface and the tip surface of the first divided body, and the vertical dimension of the engagement projection is set to be smaller than the vertical dimension of the engagement hole of the first divided body. A resin pipe connecting device characterized in that interference between the engaging portion and the engaging projection is avoided when the first divided body is placed over the flange portion while the engaging projection is inserted into the engaging hole.

2. The resin pipe connecting device according to claim 1, characterized in that the engagement hole has a main hole portion for accommodating the engagement projection when the first and second divided bodies are fastened together by the fastening means, and also has a relief recess formed on the opposite side of the second divided body, which is connected to the main hole portion.

3. The connecting device for resin pipes according to claim 1 or 2, wherein the other ends of the first and second divided bodies each have support portions that protrude radially outward, and the fastening means is composed of a bolt that passes through these support portions and a nut that is screwed onto the bolt, and a protrusion for preventing the nut from rotating is formed on either of the support portions.

4. A resin pipe connecting device according to any one of claims 1 to 3, characterized in that a short cylindrical inner core is arranged on the inner circumference of one end of each of the two resin pipes.

5. The resin pipe connecting device according to any one of claims 1 to 4, characterized in that the first and second divided parts are formed of glass fiber-reinforced resin.

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