Plastic pipe connection device and manufacturing method thereof

Abstract

To provide a connection device for a resin tube which can have a simplified configuration without decrease in strength.SOLUTION: A connection device for connecting two resin tubes 1, 2 in a state where flange portions 1a, 2a abut against each other, includes first and second split parts 10, 20 made of resin. The first and second split parts 10, 20 respectively include first and second body parts 11, 21 in which fitting grooves 12, 22 for storing the flange parts 1a, 1b are formed. A hinge receiving part 15 having an engagement hole 16 is provided on one end of the first body part 11, and a hinge projection 25 which is inserted into the engagement hole 16 is formed on one end of the second body part 21. First and second fastening receive parts 18, 28 are formed on the other ends of the first and second body parts 11, 21, respectively, which are fastened by fastening means 30 in a direction closer to each other. On an outer surface of the hinge receive part 15, a protrusion part 40 is formed having a width narrower than the hinge receiving part 15. The protrusion part 40 extends in an extending direction of the hinge receiving part 15 and closes an outer side of the engagement hole.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an apparatus for connecting two plastic pipes each having a flange portion at one end without welding, and a method for manufacturing the same. [Background technology]

[0002] When it is required to connect plastic pipes without fusing at the construction site of water supply piping, a plastic pipe with a flange at the end is manufactured in the factory by butt fusing a short pipe with a flange to the plastic pipe body. The flange has an abutting 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 abutting them together.

[0003] The connecting device includes a pair of divided bodies, a hinge means for rotatably connecting one end of the pair of divided bodies to each other, and a fastening means for tightening the other end of the pair of divided bodies so as to bring them closer to each other. A fitting groove is formed on the inner periphery of each of the pair of divided bodies, and a tapered surface is formed on both sides of the fitting groove, the tapered surface having the same taper angle as the tapered surface of the flange portion.

[0004] To briefly explain the process of connecting plastic pipes using the above connecting device, the pair of divided bodies are opened, and the flanges of the two plastic pipes are placed in the fitting grooves of the lower divided body. Next, the upper divided body is rotated in the closing direction around the hinge means, and the flanges of the two plastic pipes are loosely fitted into the fitting grooves. Finally, conclusion When the pipes are tightened by the tightening means, the tapered surfaces on both sides of the fitting groove 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 brings the flanges of the two plastic pipes closer together. As a result, the two plastic pipes are connected with the butt faces of the flanges coming into contact.

[0005] Patent Document 1 proposes a connection device with a simplified hinge means. That is, a hinge receiving portion extending toward the second division is provided on the radially outer side of one circumferential end of the first division. An engagement hole is formed in this hinge receiving portion. A hinge protrusion protruding toward the radially outer side is provided on one end of the second division. The first and second divisions are rotatably connected by inserting the hinge protrusion of the second division into the engagement hole of the first division. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2021-50789 A Summary of the Invention [Problem to be solved by the invention]

[0007] In the manufacturing device of Patent Document 1, the hinge receiving portion of the first divided body, especially the portion of the hinge receiving portion on the tip side of the engagement hole, has weak mechanical strength despite receiving a large load, and therefore there is a limit to maintaining the connection performance over a long period of time. The inventors have found that the cause of this decrease in mechanical strength is the occurrence of welds and voids. That is, when the first divided body is injection molded, the resin flow from the main body is divided into both sides of the engagement hole and rejoins at the tip of the hinge receiving portion, so that welds are generated at this joining portion and voids are generated due to air entrapment. In particular, in the case of glass fiber strength resin, the orientation of the glass fibers is disturbed by the welds, resulting in a 20 to 50% decrease in strength. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention provides a connection device for connecting two plastic pipes having annular flange portions at one end in a state where the flange portions are butted together, comprising: The pipe has first and second divided bodies made of resin, the first and second divided bodies having first and second main bodies, respectively, with an arc-shaped fitting groove formed on the inner circumference for accommodating the flange portion, one end of the first main body is integrally provided with a hinge receiving portion extending toward the second divided body and having an engagement hole, one end of the second main body is integrally provided with a hinge protrusion protruding radially outward and inserted into the engagement hole, the hinge receiving portion and the hinge protrusion form a hinge means for rotatably connecting one ends of the first and second main bodies along a plane perpendicular to the axis of the resin pipe, and the other ends of the first and second main bodies are connected to each other. conclusion The hinge receiving portion has an outer surface having a width smaller than that of the hinge receiving portion. and is integral with the hinge receiving portion. A raised portion is formed, and the raised portion extends in the extending direction of the hinge receiving portion to close the outside of the engagement hole.

[0009] According to the above configuration, when the first divided body is injection molded, the resin from the first main body not only flows to both sides of the engagement hole when it flows into the hinge receiving part, but also flows through the raised part that spans both sides of the engagement hole and is supplied to the tip of the hinge receiving part, so that it is possible to suppress the generation of welds due to the resin split into both sides of the engagement hole rejoining at the tip of the hinge receiving part and the generation of voids due to air entrainment. Since the raised part is narrower than the width of the hinge receiving part, it is possible to ensure the flow of the intermediate flow without significantly increasing the resin flow on both sides of the engagement hole, and from this point of view, it is possible to reliably suppress the generation of welds and voids at the tip of the hinge receiving part. As a result, it is possible to reduce the decrease in strength of the tip of the hinge receiving part. In addition, since the raised part blocks the outside of the engagement hole, it is possible to increase the strength of the entire hinge receiving part.

[0010] Preferably, the protuberance extends to a tip of the hinge receiving portion. Preferably, the hinge receiving portion has a protruding portion protruding radially outward and an extending portion extending from the tip of the protruding portion toward the second partition body, forming an approximately L-shape, the engagement hole being formed in the extending portion, and the raised portion being formed continuously from the outer surface of the protruding portion to the outer surface of the extending portion. Preferably, the height of the protrusion from the outer surface of the hinge receiving portion is 10% or more of the wall thickness of the hinge receiving portion. According to the above-described configuration, the resin can be smoothly and sufficiently supplied through the raised portion to the tip end of the hinge portion, so that the occurrence of welds and voids can be further suppressed.

[0011] When the first and second halves are formed from resin containing glass fibers in order to reduce weight and increase strength, disorder of the glass fibers at the resin junction can be suppressed, thereby avoiding a significant decrease in strength at the tip of the hinge receiving portion.

[0012] Immediately after injection molding, the other ends of the first and second main body portions are integrally provided with first and second fastening receiving portions which protrude radially outward, and these first and second fastening receiving portions are fastened in a direction approaching each other by the fastening means, and convex portions are formed on the tip surfaces of the hinge receiving portion, the tip surfaces of the hinge protrusions, and the tip surfaces of the first and second fastening receiving portions. According to the above-mentioned configuration, the protruding portion that does not play a role in connecting the resin pipe can be the final filling location of the resin.

[0013] Another aspect of the present invention is a method for manufacturing a connecting device for plastic pipes, wherein a first mold for molding the first split body has a first body portion molding space for molding the first body portion, a hinge receiving portion molding space for molding the hinge receiving portion, and a protuberance portion molding space for molding the protuberance, and when injection molding the first split body, resin is injected from a gate connected to the first body portion molding space, and this resin flows through the first body portion molding space into the hinge receiving portion molding space and the protuberance portion molding space.

[0014] Preferably, the first and second fastening receiving portions, which are fastened to each other by the fastening means, are formed at the other end of the first and second main body portions of the plastic pipe connecting device so as to protrude radially outward, The first mold further has a first fastening receiving portion molding space for molding the first fastening receiving portion, and the gate is arranged at a position corresponding to the circumferential center and the axial center of the outer peripheral surface of the first main body portion, and during injection molding of the first split body, resin injected from the gate into the first main body portion molding space flows toward the hinge receiving portion molding space and the ridge molding space, as well as flowing toward the first fastening receiving portion molding space on the opposite side, and the second mold for molding the second split body has a second main body portion molding space for molding the second main body portion, a hinge protrusion molding space for molding the hinge protrusion, and a second fastening receiving portion molding space for molding the second fastening receiving portion, and the gate is arranged at a position corresponding to the circumferential center and the axial center of the outer peripheral surface of the second main body portion, and during injection molding of the second split body, resin injected from the gate into the second main body portion molding space flows toward the hinge protrusion molding space and flows into the second fastening receiving portion molding space on the opposite side. According to the above method, the vicinity of both ends of the first and second divided bodies can be the final resin filling locations, and the first and second main body portions can be prevented from being the final resin filling locations, thereby ensuring the strength of the first and second main body portions.

[0015] Preferably, the first mold further has a first convex portion molding space for molding a first convex portion on a tip surface of the hinge receiving portion and a second convex portion molding space for molding a second convex portion on a tip surface of the first fastening receiving portion, and during injection molding of the first divided body, a resin that has passed through the hinge receiving portion molding space and the raised portion molding space is finally filled into the first convex portion molding space, and a resin that has passed through the first fastening receiving portion molding space is finally filled into the second convex portion molding space, The second mold further has a third convex portion molding space for molding a third convex portion on the tip surface of the hinge protrusion, and a fourth convex portion molding space for molding a fourth convex portion on the tip surface of the second fastening receiving portion, and during injection molding of the second divided body, resin that has passed through the hinge protrusion molding space is finally filled into the third convex portion molding space, and resin that has passed through the second fastening receiving portion molding space is finally filled into the fourth convex portion molding space. According to the above method, when the first and second sections are injection molded, the convex portion that does not play a role in connecting the resin tube can be the final filling point, thereby reliably suppressing the occurrence of welds in other areas. Effect of the Invention

[0016] According to the present invention, it is possible to reduce a decrease in strength of the hinge-receiving portion of the first split body that is caused by welds formed during injection molding. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a longitudinal cross-sectional view showing the steps of connecting two plastic pipes using a plastic pipe connecting device according to one embodiment of the present invention, where (A) shows a state midway through the connecting process, and (B) shows a state after the connecting process has been completed. [Diagram 2] 5A and 5B are cross-sectional views sequentially showing a resin pipe connecting process using the connecting device, in which (A) shows a state during the connecting process, and (B) shows a state after the connecting process is completed. [Diagram 3] 11 is a front view of a pair of upper and lower split bodies of the connection device immediately after injection molding, as viewed from the axial direction of the resin pipe. FIG. [Figure 4] FIG. 4 is a side view showing a pair of upper and lower divided bodies immediately after the injection molding. [Diagram 5] 1A is a plan view of the upper half body, and FIG. 1B is a bottom view of the lower half body. [Figure 6] 13A and 13B are perspective views of the upper division body as viewed from different directions. [Figure 7] 13A and 13B are perspective views of the lower division body as viewed from different directions. [Figure 8] FIG. 4 is a side view showing the flow of resin when the upper half body is injection molded. [Figure 9] FIG. 11 is a side view showing the flow of resin when injection molding a known upper half body serving as a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. <Structure of resin pipe> First, referring to Fig. 1, the plastic pipes 1 and 2 to be connected will be described. The plastic pipes 1 and 2 are made of a plastic such as polyethylene, and have annular flanges 1a and 2a at one end. The tip surfaces of the flanges 1a and 2a form butt surfaces 1x and 2x perpendicular to the axis L, and the opposite surfaces form tapered surfaces 1y and 2y. The plastic pipes 1 and 2 are manufactured by butt welding a short pipe having the flanges 1a and 2a to a plastic pipe body. An annular groove 1z is formed in the butt 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.

[0019] A short cylindrical incore 4 is disposed on the inner circumference 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 outwardly at one end. This flange 4a engages with annular recesses 1b and 2b formed on the inner circumference of the tip of each of the plastic pipes 1 and 2, so that the incore 4 is attached 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.

[0020] <Configuration of the connection device> Next, a connection device 5 for connecting the resin pipes 1 and 2 will be described with reference to Figures 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 substantially semi-cylindrical main bodies 11, 21 (first and second main bodies). The inner diameter of the main bodies 11, 21 is substantially equal to the outer diameter of the resin pipes 1, 2.

[0021] The main body portions 11, 21 of the segments 10, 20 have a circumferential dimension slightly shorter than that of a complete semicylinder. That is, the circumferential end faces 11a, 11b of the main body portion 11 of the upper segment 10 are slightly set back from a plane passing through the radial center of the inner circumference of the main body portion 11 and are parallel to this plane. Similarly, the circumferential end faces 21a, 21b of the main body portion 21 of the lower segment 20 are slightly set back from a plane passing through the radial center of the inner circumference of the main body portion 21 and are parallel to this plane.

[0022] The inner circumference of the main body 11, 21 of the divided body 10, 20 is formed with a fitting groove 12, 22 extending in a substantially semicircular shape in the circumferential direction. Tapered surfaces 12a, 22a are formed on both sides of the fitting groove 12, 22. The taper angle of the tapered surfaces 12a, 22a is equal to the taper angles 1y, 2y of the flanges 1a, 2a of the plastic pipes 1, 2. The cross-sectional shape of the fitting groove 12, 22 is substantially equal to the cross-sectional shape of the flanges 1a, 2a when the butt surfaces 1x, 2x of the flanges 1a, 2a are in contact with each other, as described below.

[0023] A hinge receiver 15 is provided integrally with the main body 11 at one end of the main body 11 of the upper division body 10. This hinge receiver 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 division body 20) from the tip of this protruding portion 15a, beyond the end face 11a, and perpendicular to the end face 11a, forming a substantially L-shape.

[0024] An engagement hole 16 is formed in the extension 15b of the hinge receiving portion 15. The engagement hole 16 has a substantially rectangular shape. The tip end of the hinge receiving portion 15, i.e., a portion 15x below the engagement hole 16, serves as a load receiving portion.

[0025] A hinge protrusion 25 that protrudes radially outward is formed integrally with the main body 21 at one end of the main body 21 of the lower half 20. The cross-sectional shape of the hinge 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 hinge protrusion 25 are slightly shorter than the vertical and horizontal dimensions of the engagement hole 16 of the upper half 10. As described later, the hinge protrusion 25 of the lower divisional body 20 is inserted into the engagement hole 16 of the upper divisional body 10 to form a hinge means H. This hinge means H connects the upper divisional body 10 to the lower divisional body 20 so as to be relatively rotatable along a plane perpendicular to the axis L of the resin pipes 1, 2.

[0026] Fastening receiving portions 18, 28 (first and second fastening receiving portions) protruding 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 bodies 10, 20. The lower surface of the fastening receiving portion 18 is flush with the end surface 11b of the main body portion 11, and the upper surface of the fastening receiving portion 28 is flush with the end surface 21b of the main body portion 21. Through holes 18a, 28a are formed in the fastening receiving portions 18, 28. A rotation preventing protrusion 29 surrounding the through hole 28a is formed on the lower surface of the fastening receiving portion 28. As shown in FIG. 2(B), fastening means 30 for fastening the fastening receiving portions 18, 28 includes a bolt 31 and a nut 32.

[0027] In this embodiment, a protuberance 40 is formed on the outer surface of the hinge receiving portion 15, extending continuously over the entire length of the hinge receiving portion 15 from the base end of the protruding portion 15a to the tip of the extending portion 15. The protuberance 40 covers the outside of the engagement hole 16. As shown in FIG. 2(B), the height T 40 is the thickness T of the extension 15b of the hinge receiving portion 15 15 4, the width W40 of the raised portion 40 (the dimension in the direction of the axis L of the resin pipes 1, 2) is larger than the width W16 of the engagement hole 16 and smaller than the width W15 of the hinge receiving portion 15. More specifically, both side edges of the raised portion 40 are located far from both side edges of the hinge receiving portion 15 and close to both side edges of the engagement hole 16.

[0028] <Resin pipe connection process using a connection device> The process of connecting the plastic pipes 1, 2 using the connecting device 5 will now be described. As shown in Figures 1(A) and 2(A), first, the flange portions 1a, 2a of the plastic pipes 1, 2 are placed on the lower divided body 20 with the O-ring 3 brought close enough to lightly contact the abutting surface 2x of the plastic pipe 2. The flange portions 1a, 2a are aligned with the fitting groove 22, and a part of them is received in the fitting groove 22.

[0029] Next, the upper divisional body 10 is moved laterally toward the lower divisional body 20 while still in the inclined position, and the hinge projection 25 is inserted into the engagement hole 16 of the hinge receiving portion 15 . Next, the upper half body 10 is rotated about the fulcrum F so as to approach the lower half body 20, whereby the fastening receiving portion 18 of the upper half body 10 approaches and faces the fastening receiving portion 28 of the lower half body 20. In this state, a portion of the flange portions 1a, 2a is also accommodated in the fitting groove 12 of the upper half body 10.

[0030] Next, with the nut 32 fitted between the anti-rotation projections 29 so as not to rotate, the bolt 31 is passed through the through holes 18a, 28a of the fastening receiving portions 18, 28 of the divisional bodies 10, 20, screwed into the nut 32, and turned in the tightening direction, as shown in FIG. 2(B). As a result, the flange portions 1a, 2a of the plastic pipes 1, 2 are clamped and tightened by the lower divisional body 20 and the upper divisional body 10. This radially inward tightening force is converted into an axial force that brings the flange portions 1a, 2a closer to 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 flange portions 1a, 2a. As a result, as shown in FIG. 1(B), the butt surfaces 1x, 2x of the flange portions 1a, 2a come into surface contact with each other with the elastic deformation of the O-ring 3. In this way, the connection process is completed.

[0031] Tightening the bolts 31 brings the fastening receiving portions 18, 28 of the sections 10, 20 closer to each other, and a force acts in the direction in which the opposite sides move away from each other. Therefore, the hinge protrusion 25 strongly hits the tip portion 15x of the hinge receiving portion 15. This allows the lower section 20 and the upper section 10 to strongly fasten the flange portions 1a, 2a.

[0032] <Shape of the first and second split bodies immediately after injection molding> 3 to 7 show the shapes of the split bodies 10, 20 immediately after injection molding. A throw-away rib 51 (first convex portion) is formed on the tip end surface (lower end surface) of the hinge receiving portion 15 of the upper split body 10 immediately after injection molding. This throw-away rib 51 is formed in the center of the width direction (axis L direction of the resin pipes 1, 2) of the tip end surface of the hinge receiving portion 15 and extends in the thickness direction of the hinge receiving portion 15. A throw-away rib 52 (second convex portion) extending in the thickness direction of the fastening receiving portion 18 is also formed in the center of the width direction of the fastening receiving portion 18 of the upper split body 10.

[0033] Immediately after injection molding, a throw-away rib 53 (third convex portion) extending in the thickness direction of the hinge protrusion is formed in the widthwise center of the tip surface of the hinge protrusion 25 of the lower half body 20, and a throw-away rib 54 (fourth convex portion) extending in the thickness direction is also formed in the widthwise center of the tip surface of the fastening receiving portion 28.

[0034] The above-mentioned sacrificial ribs 51-54 play no role in connecting the resin pipes 1, 2, and are therefore removed after molding, so that the divided bodies 10, 20 have a final product shape without the sacrificial ribs 51-54 as shown in Figures 1 and 2. However, if the sacrificial ribs 51-54 do not interfere with the function of the connection device 5, they may be left as they are rather than being removed. Although the sacrificial ribs 51-54 are each formed at one location in the widthwise center, they may also be formed at two locations, for example, symmetrically positioned with respect to the widthwise center.

[0035] As shown in Figs. 5 to 7, gate marks 60, 70 are left on the outer circumferential surfaces of the main bodies 11, 21 of the divisional bodies 10, 20 at the circumferential center and the widthwise center, respectively.

[0036] <Manufacturing method of connection device> Next, a description will be given of a manufacturing method for the connection device 5, in particular the injection molding process for the split bodies 10 and 20. Below, a description will be given of the molds and molding space for injection molding the split bodies 10 and 20, respectively, but illustrations thereof will be omitted since their shapes can be easily understood from the shapes of the split bodies 10 and 20 immediately after molding shown in Figures 3 to 7.

[0037] The first mold used for injection molding the upper half body 10 includes a main body molding space (first main body molding space) for molding the main body 11, a hinge receiving portion molding space for molding the hinge receiving portion 15, a fastening receiving portion molding space (first fastening receiving portion molding space) for molding the fastening receiving portion 18, a protuberance molding space for molding the protuberance 40, and a sacrificial rib molding space (first and second protuberance molding spaces) for molding the sacrificial ribs 51, 52. The gate is connected to the main body molding space and is located at a position corresponding to the gate mark 60 described above.

[0038] During the injection molding of the upper half body 10, the resin injected from the gate fills the main body molding space, flows into the hinge receiving part molding space and the raised part molding space, and finally fills the temporary rib molding space, as well as flows into the fastening receiving part molding space on the opposite side, and finally fills the temporary rib molding space. This results in the molding of the main body 11, hinge receiving part 15, raised part 40, and temporary rib 51, and also the molding of the fastening receiving part 18 and temporary rib 52 on the opposite side.

[0039] The flow of resin in the hinge receiving portion 15 will be described. First, the flow of resin in the hinge receiving portion of a known connection device (connection device disclosed in Patent Document 1) serving as a comparative example will be described with reference to FIG. 9. Note that components in the comparative example in FIG. 9 that correspond to this embodiment are given the same numbers in the figure. In this comparative example, a protuberance that closes the engagement hole 16 is not formed in the hinge receiving portion 15. Therefore, as shown by the arrows in FIG. 9, the resin from the main body molding space branches off to both sides of the hinge receiving portion molding space (both sides sandwiching the engagement hole 16) and rejoins at the tip of the hinge receiving portion molding space. As a result, welds and voids are likely to occur.

[0040] In contrast, in this embodiment, as shown by the arrows in Figure 8, the resin flows from the main body molding space along both sides of the hinge receiving part molding space and also flows into the central raised part molding space and is supplied to the tip of the hinge receiving part molding space, so that it is possible to suppress the occurrence of welds when the resin that has flowed along both sides of the hinge receiving part molding space joins together at the tip of the hinge receiving part molding space, and it is also possible to suppress the occurrence of voids due to air being entrained as a result of this joining.

[0041] Since the width of the raised portion 40 is narrower than the width of the hinge receiving portion 15, the flow of resin in the raised portion molding space can be ensured without significantly increasing the resin flow rate on both sides of the hinge receiving portion molding space, and this also suppresses the occurrence of welds and voids. In addition, since the raised portion 40 is formed over the entire length of the hinge receiving portion 15, spanning the protruding portion 15a and the extending portion 15b, and the height of the raised portion 40 is 10% or more of the thickness of the hinge receiving portion 15, a sufficient amount of resin can be supplied from the raised portion molding space to the tip of the hinge receiving portion molding space, and this also reliably suppresses the occurrence of welds and voids. As a result, the decrease in strength of the hinge receiving portion 15 can be reduced. In particular, when molding with glass fiber reinforced resin, the disturbance of the resin fiber orientation due to merging can be suppressed, and a significant decrease in strength can be avoided.

[0042] Since resin injection begins from the circumferential and widthwise centers of the main body molding space, the final filling point becomes the end of the molding space of the upper section 10, and it is possible to reliably prevent the main body 11 from becoming the final filling point, thereby avoiding the inconvenience of the strength of the main body 11 being reduced by the welds.

[0043] In addition, the throw-away ribs 51, 52, which do not contribute to the original function of the connection device 5, become the final filling points, and the hinge receiving portion 15 and the fastening receiving portion 18 do not become the final filling points, so that a decrease in the strength of the hinge receiving portion 15 and the fastening receiving portion 18 can be avoided.

[0044] The second mold used for injection molding the lower half body 20 includes a main body molding space (second main body molding space) for molding the main body 21, a hinge protrusion molding space for molding the hinge protrusion 25, a fastening receiving portion molding space (second fastening receiving portion molding space) for molding the fastening receiving portion 28, and a sacrificial rib molding space (third and fourth protrusion molding spaces) for molding the sacrificial ribs 53 and 54. The gate is connected to the main body molding space and is located at a position corresponding to the gate mark 70 described above.

[0045] During the injection molding of the lower section 20, the resin injected from the gate fills the main body molding space, flows into the hinge protrusion molding space, and finally fills the temporary rib molding space, while also flowing into the fastening receiving portion molding space on the opposite side, and finally filling the temporary rib molding space. This results in the molding of the main body 21, hinge protrusion 25, and temporary rib 53, while also molding the fastening receiving portion 28 and temporary rib 54 on the opposite side.

[0046] Since resin injection begins from the circumferential and widthwise centers of the main body molding space, the final filling point becomes the end of the molding space of the lower section 20, which reliably prevents the main body 21 from becoming the final filling point, thereby avoiding the inconvenience of the strength of the main body 21 being reduced by the welds.

[0047] In addition, the throw-away ribs 53, 54, which do not contribute to the original function of the connection device 5, become the final filling points, and the hinge protrusion 25 and the fastening receiving portion 28 do not become the final filling points, so that a decrease in the strength of the hinge protrusion 25 and the fastening receiving portion 28 can be avoided.

[0048] The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. [Industrial Applicability]

[0049] The present invention can be applied to an apparatus for connecting plastic pipes having flanges at their ends and a method for manufacturing the same. [Explanation of symbols]

[0050] 1, 2 Plastic pipe 1a, 2a Flange part 1x, 2x butt faces 1y, 2y tapered surface 5 Connecting Devices 10 Upper division body (first division body) 11 Main body part (first main body part) 12 Fitting groove 12a Tapered surface 15 Hinge receiving part 15a Protrusion 15b Extension 16 Engagement hole 18 Fastening receiving portion (first fastening receiving portion) 20 Lower divided body (second divided body) 21 Main body part (second main body part) 22 Fitting groove 22a Tapered surface 25 Hinge protrusion 28 Fastening receiving part (second fastening receiving part) 30 Fastening means 31 Volts 32 Nut 40 Ridge 51~54 Temporary ribs (1st to 4th convex parts) H Hinge Means L Axis of resin pipe

Claims

1. A connection device for connecting two plastic pipes having annular flanges at one end with the flanges butted together, the first and second divided bodies are made of resin, and the first and second divided bodies have first and second main bodies, respectively, each having an arc-shaped fitting groove formed on an inner periphery thereof for accommodating the flange portion; A hinge receiving portion extending toward the second divided body and having an engagement hole is integrally provided at one end of the first main body, and a hinge protrusion protruding radially outward is integrally provided at one end of the second main body and inserted into the engagement hole, the hinge receiving portion and the hinge protrusion form a hinge means that rotatably connects one ends of the first and second main bodies along a plane perpendicular to the axis of the plastic tube, and the other ends of the first and second main bodies are fastened together by a fastening means in a direction approaching each other. A plastic pipe connection device characterized in that a raised portion having a width narrower than the width of the hinge receiving portion and integral with the hinge receiving portion is formed on the outer surface of the hinge receiving portion, and the raised portion extends in the extension direction of the hinge receiving portion to block the outside of the engagement hole.

2. 2. The resin pipe connecting device according to claim 1, wherein the raised portion extends to a tip end of the hinge receiving portion.

3. the hinge receiving portion has a protruding portion protruding radially outward and an extending portion extending from a tip end of the protruding portion toward the second divided body side, and is generally L-shaped, and the engagement hole is formed in the extending portion, 3. The resin pipe connecting device according to claim 2, wherein the raised portion is formed continuously from the outer surface of the protruding portion to the outer surface of the extending portion.

4. 4. The resin pipe connecting device according to claim 1, wherein the height of the raised portion from the outer surface of the hinge receiving portion is 10% or more of the wall thickness of the hinge receiving portion.

5. 5. The resin pipe connecting device according to claim 1, wherein the first and second divided bodies are made of a resin containing glass fiber.

6. The other ends of the first and second main bodies are integrally provided with first and second fastening receiving portions protruding radially outward, respectively, and the first and second fastening receiving portions are fastened in a direction approaching each other by the fastening means, A plastic pipe connecting device as described in any one of claims 1 to 5, characterized in that a convex portion is formed on an end surface of the hinge receiving portion, an end surface of the hinge protrusion, and an end surface of the first and second fastening receiving portions.

7. A method for manufacturing a resin pipe connecting device according to any one of claims 1 to 5, a first die for molding the first divided body includes a first body portion molding space for molding the first body portion, a hinge receiving portion molding space for molding the hinge receiving portion, and a raised portion molding space for molding the raised portion, A manufacturing method for a resin pipe connection device, characterized in that, during injection molding of the first divided body, resin is injected from a gate connected to the first main body portion molding space, and this resin flows through the first main body portion molding space into the hinge receiving portion molding space and the raised portion molding space.

8. At the other end of the first and second main body parts of the plastic pipe connecting device, first and second fastening receiving parts that are fastened to each other by the fastening means are formed so as to protrude radially outward, The first mold further has a first fastening receiving portion molding space for molding the first fastening receiving portion, and the gate is disposed at a position corresponding to a circumferential center of an outer circumferential surface of the first main body portion and a center in the axial direction, During injection molding of the first divided body, resin injected from the gate into the first main body portion molding space flows toward the hinge receiving portion molding space and the protruding portion molding space, and also flows toward the first fastening receiving portion molding space on the opposite side, a second mold for molding the second divided body has a second body portion molding space for molding the second body portion, a hinge protrusion molding space for molding the hinge protrusion, and a second fastening receiving portion molding space for molding the second fastening receiving portion, and the gate is disposed at a position corresponding to a circumferential center of an outer circumferential surface of the second body portion and a center in the axial direction; A manufacturing method for a resin pipe connection device as described in claim 7, characterized in that when the second divided body is injection molded, the resin injected from the gate into the second main body portion molding space flows toward the hinge protrusion molding space and also flows into the second fastening receiving portion molding space on the opposite side.

9. the first die further has a first convex portion molding space for molding a first convex portion on a tip surface of the hinge receiving portion and a second convex portion molding space for molding a second convex portion on a tip surface of the first fastening receiving portion, During injection molding of the first divided body, a resin that has passed through the hinge receiving portion molding space and the raised portion molding space is finally filled into the first convex portion molding space, and a resin that has passed through the first fastening receiving portion molding space is finally filled into the second convex portion molding space, the second mold further has a third convex portion molding space for molding a third convex portion on a tip surface of the hinge protrusion, and a fourth convex portion molding space for molding a fourth convex portion on a tip surface of the second fastening receiving portion, A manufacturing method for a resin pipe connection device as described in claim 8, characterized in that during injection molding of the second separate body, resin that has passed through the hinge protrusion molding space is finally filled into the third convex portion molding space, and resin that has passed through the second fastening receiving portion molding space is finally filled into the fourth convex portion molding space.

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