Electric fusion joint

Abstract

To provide an elbow type electric fusion joint with excellent convenience.SOLUTION: An electric fusion joint 10 is an elbow type electric fusion joint comprising a joint body 12 including a curved pipe part 14 extending laterally and an electric fusion socket part 16 formed so as to extend from each end of the curved pipe part. A bottom part of an outside surface of the joint body is formed with a base part 30 having a flat bottom surface 30a that is in contact with an installation surface such as the ground.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an electric fusion joint, and in particular to, for example, an elbow-type electric fusion joint that includes a joint body including a bent pipe portion and an electric fusion socket portion. [Background technology]

[0002] An example of a conventional elbow-type electric fusion joint is disclosed in Patent Document 1. The electric fusion joint (elbow-type EF joint) in Patent Document 1 is made of a thermoplastic resin and has an elbow-shaped joint body mainly composed of straight pipe sections on both sides and a curved pipe section between them, and an electric heating wire disposed on the inner periphery of the joint body. The joint body is a member formed by bending a straight pipe, and the electric heating wire is composed of an embedded section wound around the inner periphery of each straight pipe section and a connecting section that connects the ends of each embedded section. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-283813 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology of Patent Document 1, the bottom of the outer surface of the joint body is curved, which makes it unstable when placed on the ground, etc., and is inconvenient.

[0005] SUMMARY OF THE PRESENT EMBODIMENTS It is therefore a primary object of the present invention to provide a novel electrofusion joint.

[0006] Another object of the present invention is to provide an electric fusion joint which is highly convenient. [Means for solving the problem]

[0007] The first invention is an elbow-type electric fusion joint comprising a joint body including a curved pipe portion extending laterally and an electric fusion receiving portion extending from each of both ends of the curved pipe portion, and a base portion formed on the bottom of the outer surface of the joint body and having a planar bottom surface in contact with the mounting surface.

[0008] In a first aspect of the present invention, the electric fusion joint is an elbow-type electric fusion joint (EF elbow) and includes a joint body made of synthetic resin. The joint body includes a curved pipe portion extending laterally and an electric fusion socket portion extending from each of both ends of the curved pipe portion. A base portion having a flat bottom surface that contacts the mounting surface is formed at the bottom of the outer surface of the joint body.

[0009] According to the first aspect of the present invention, since the joint body has a seat portion formed on the bottom of the outer surface thereof, it can be stably placed on the placement surface, which provides excellent convenience.

[0010] A second invention is dependent on the first invention, and includes two pedestals formed at a predetermined distance apart.

[0011] According to the second aspect of the present invention, the electric fusion joint can be stably supported in a well-balanced manner by the base portion.

[0012] The third invention is dependent on the second invention, and the electric fusion joint is formed by injection molding, and a gate mark, which is generated at the gate position where synthetic resin is poured into a mold during injection molding, is formed between two base portions.

[0013] According to the third aspect of the present invention, the electric fusion joint can be stably supported by the base without the need for time-consuming processing of the gate trace portion.

[0014] A fourth invention is according to the first or second invention, and the seat is formed on a bottom of an outer surface of the curved pipe portion.

[0015] According to the fourth aspect of the present invention, it is possible to prevent distortion that would occur during injection molding due to a change in the thickness of the receiving portion, and therefore it is possible to prevent the inner surface (inner diameter) of the receiving portion from deviating from a perfect circle.

[0016] The fifth invention is dependent on the first or second invention, and the bottom surface of the base portion is formed flush or approximately flush with the lowest part of the joint body (i.e., the part that protrudes most downward when viewed from the side).

[0017] According to the fifth invention, the thickness of the joint body at the portion where the base portion is formed can be prevented from becoming too large compared to other portions, thereby reducing distortion that occurs during injection molding and reducing the amount of resin used.

[0018] In a sixth aspect of the invention, the pedestal portion is formed on the bottom of the outer surface of the curved tube portion, and the bottom surface of the pedestal portion is formed flush or approximately flush with the lowest portion of the electric fusion port portion.

[0019] According to the sixth aspect of the present invention, since the electric fusion joint is supported not only by the base portion but also by the lowest portion of the electric fusion socket portion, the electric fusion joint can be more stably placed on the placement surface. In addition, distortion that occurs during injection molding can be reduced, and the amount of resin used can be reduced. Effect of the Invention

[0020] According to this invention, since the joint body has a seat portion formed on the bottom of the outer surface thereof, it can be stably placed on the placement surface, and is highly convenient.

[0021] The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the embodiments with reference to the drawings. [Brief description of the drawings]

[0022] [Figure 1] 1 is a front view showing an electric fusion joint according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a rear view showing the electric fusion joint of FIG. [Diagram 3] FIG. 2 is a plan view showing the electric fusion joint of FIG. [Figure 4] FIG. 2 is a bottom view showing the electric fusion joint of FIG. 1. [Diagram 5] 2 is a cross-sectional view showing a cross section of an electric fusion joint at the VV line in FIG. 1. [Figure 6] 6 is a cross-sectional view showing a cross section of the electric fusion joint taken along line VI-VI in FIG. [Figure 7] FIG. 11 is a front view showing an electric fusion joint according to another embodiment of the present invention. [Figure 8] FIG. 8 is a rear view showing the electric fusion joint of FIG. [Figure 9] FIG. 8 is a plan view showing the electric fusion joint of FIG. [Figure 10] FIG. 8 is a bottom view showing the electric fusion joint of FIG. 7. [Figure 11] 10 is a cross-sectional view showing a cross section of the electric fusion joint taken along line XI-XI in FIG. [Figure 12] 8 is a cross-sectional view showing a cross section of the electric fusion joint taken along line XII-XII in FIG. 7. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Referring to FIG. 1, an electric fusion joint 10 according to one embodiment of the present invention is an elbow-type electric fusion joint (EF elbow) that forms a curved pipe by electrically fusion joining synthetic resin pipes in a direction in which they intersect with each other.

[0024] The purpose and diameter of the piping to be constructed using the electric fusion joint 10 are not particularly limited, but the electric fusion joint 10 is suitably used for connecting polyethylene synthetic resin pipes with a nominal diameter (inner diameter) of 20 mm to 150 mm for water distribution or gas use. The following description will be given taking an electric fusion joint 10 with a nominal diameter of 100 mm as an example. The manufacturing method of the electric fusion joint 10 is not particularly limited, but the electric fusion joint 10 of this embodiment is formed by injection molding.

[0025] As shown in Figures 1 to 6, the electric fusion joint 10 includes a joint body 12 formed of a polyolefin-based synthetic resin such as polyethylene and polybutene. The joint body 12 includes a curved pipe section 14 extending laterally, and electric fusion socket sections 16 (hereinafter simply referred to as "socket sections 16") extending from both ends of the curved pipe section. That is, the joint body 12 includes the curved pipe section 14 provided in the axial center, and socket sections 16 provided at both axial ends. In this embodiment, the curved pipe section 14 is curved by 90 degrees, and the two socket sections 16 extend (open) in directions perpendicular to each other.

[0026] The socket portion 16 is a portion that receives the end of the synthetic resin pipe to be connected. An electric heating wire (not shown) is embedded in the vicinity of the inner surface of the socket portion 16 so as to extend in a spiral shape. A stopper 18 that defines the inner end of the socket portion 16 is formed on the inner side of the electric heating wire. In this embodiment, the annular stopper 18 is formed by reducing the diameter of the inner surface of the inner end of the socket portion 16 in a stepped shape. However, the stopper 18 may be a plurality of protrusions formed at a predetermined interval in the circumferential direction. When the end of the synthetic resin pipe is connected to the socket portion 16, the tip of the synthetic resin pipe hits the stopper 18, thereby defining the insertion length of the synthetic resin pipe into the socket portion 16.

[0027] Both ends of the heating wire are connected to power connection terminals 20 formed to protrude from the top of the tip of the receptacle portion 16. When the power connection terminals 20 are connected to a power source and an electric current is passed through the heating wire, heat is generated. This heat heats and melts the resin at the joint surface between the receptacle portion 16 and the synthetic resin pipe, thereby fusion-joining the receptacle portion 16 and the synthetic resin pipe. Furthermore, an indicator 22 is formed at the top of the receptacle portion 16, closer to the center in the axial direction than the power connection terminals 20. The indicator 22 is intended to indicate that the joint surface between the receptacle portion 16 and the synthetic resin pipe has been fused (or the progress of fusion).

[0028] A pedestal portion 30 is formed on the bottom of the outer surface of the joint body 12. The pedestal portion 30 has a planar bottom surface 30a (lower surface) that contacts a mounting surface such as the ground. By providing such a pedestal portion 30, the electric fusion joint 10 can be stably mounted on the mounting surface.

[0029] Here, the seat 30 can be formed on the bottom of the outer surface of the socket 16, but is preferably formed on the bottom of the outer surface of the curved pipe 14. This is because the thermal fusion performance is higher when the gap between the inner surface of the socket 16 and the outer surface of the synthetic resin pipe is uniform over the entire circumferential length, and therefore it is desirable that the inner surface (inner diameter) of the socket 16 is close to a perfect circle. That is, if the seat 30 is formed on the socket 16, the thickness of the socket 16 changes, causing distortion during injection molding, and there is a risk that the inner surface of the socket 16 may deviate from a perfect circle, but this problem can be avoided by forming the seat 30 on the curved pipe 14. In this embodiment, the outer surface bottom of the curved pipe 14 is provided with two seat parts 30 formed at a predetermined interval in the axial direction of the curved pipe 14. Specifically, a seat part 30 is formed on each of both ends of the curved pipe 14, and each seat part 30 has a substantially rectangular bottom surface 30a. The length of each side of the bottom surface 30a (i.e., the length in the axial direction of the curved pipe portion 14 and the width perpendicular thereto) is preferably set to, for example, 15 mm to 30 mm. By providing two pedestals 30 formed with a predetermined distance between them, the pedestals 30 can support the electric fusion joint 10 in a balanced and stable manner.

[0030] In addition, the bottom surface 30a of the seat portion 30 is preferably formed flush or approximately flush (for example, so as to protrude downwards by about 0.1 mm to 0.5 mm) with the lowest part (lowest part) of the joint body 12, i.e., the part that protrudes most downward when viewed from the side. This prevents the thickness of the joint body 12 where the seat portion 30 is formed from being too large compared to other parts, so that distortion generated during injection molding can be reduced and the amount of resin used can be reduced. In this embodiment, the outer surface of the base end of the socket portion 16 is formed with a larger diameter than the outer surface of the curved pipe portion 14, and the lowest part (bottom point) of the outer peripheral surface of the base end of the socket portion 16 becomes the lowest part of the joint body 12. Therefore, the bottom surface 30a of the seat portion 30 is formed approximately flush with the lowest part of the socket portion 16 (specifically, so as to protrude downwards by 0.3 mm). By making the bottom surface 30a of the base portion 30 formed on the curved pipe portion 14 flush or approximately flush with the lowest portion of the receiving portion 16, the electric fusion joint 10 is supported not only by the base portion 30 but also by the lowest portion of the receiving portion 16, so that the electric fusion joint 10 can be placed more stably on the supporting surface.

[0031] Furthermore, a gate mark 32 is formed between the two pedestal portions 30 on the bottom of the outer surface of the curved pipe portion 14 during injection molding. That is, when the electric fusion joint 10 is injection molded, synthetic resin is poured into the mold from the gate, and by arranging this gate between the two pedestal portions 30, the gate mark 32 generated at the gate position is formed between the two pedestal portions 30. In this embodiment, since the power connection terminals 20 are provided at both ends of the top of the joint body 12, it is preferable to arrange the gate at the bottom of the axial center of the curved pipe portion 14 in order to optimize the flow of synthetic resin during injection molding. If the pedestal portion 30 is provided at the bottom of the axial center of the curved pipe portion 14, the gate mark 32 will be formed on the bottom surface 30a of the pedestal portion 30, and in order for the pedestal portion 30 to stably support the electric fusion joint 10, it becomes necessary to cut the gate mark 32 flush with the bottom surface 30a of the pedestal portion 30 (i.e., as close to the edge of the product). In contrast, by arranging the gate mark 32 between the two pedestal portions 30, it is no longer necessary to cut the gate mark 32 neatly and flush, and the effort required to process the gate mark 32 can be reduced.

[0032] In other words, in this embodiment, a recess is provided in the center of the base portion 30 which extends in a curved band shape along the axial direction of the curved pipe portion 14, and the gate mark portion 32 is formed within this recess.

[0033] As described above, according to this embodiment, since the seat portion 30 is formed on the bottom of the outer surface of the joint body 12, it can be stably placed on the placement surface, and therefore, it is highly convenient.

[0034] Furthermore, since the gate mark 32 is formed between the two pedestal portions 30, the electric fusion joint 10 can be stably supported by the pedestal portions 30 without the need for time-consuming processing of the gate mark 32.

[0035] Next, an electrofusion joint 10 according to another embodiment (second embodiment) of the present invention will be described with reference to Figs. 7 to 12. In the second embodiment, an electrofusion joint 10 having a nominal diameter of 50 mm will be described as an example. In this second embodiment, the arrangement of the base portion 30 and other features are different from the above-mentioned embodiment (first embodiment). In the following description, parts common to the above-mentioned embodiment will be given the same reference numbers, and duplicate descriptions will be omitted or simplified.

[0036] As shown in Figures 7 to 12, the joint body 12 of the electric fusion joint 10 includes a curved pipe portion 14 and a socket portion 16 formed by extending from each of both ends of the curved pipe portion. The joint body 12 is also formed with a clamp portion 24 protruding from the tip surface of the socket portion 16. This clamp portion 24 has a first clamp portion 24a and a second clamp portion 24b that are divided into upper and lower halves. When a synthetic resin pipe is fusion-joined to the socket portion 16 of the electric fusion joint 10, the synthetic resin pipe is fixed by sandwiching the synthetic resin pipe between the first clamp portion 24a and the second clamp portion 24b and tightening them with a screw.

[0037] In this embodiment, one pedestal portion 30 is formed in a curved band shape at the bottom of the outer surface of the axial center portion of the curved pipe portion 14 so as to extend along the axial direction of the curved pipe portion 14. In this embodiment, the outer diameter of the axial center portion of the curved pipe portion 14 is larger than the outer diameter of other portions of the joint body 12 such as the socket portion 16, and the lowest portion (bottom point) of the outer circumferential surface of the central portion of the curved pipe portion 14 becomes the lowest portion of the joint body 12. The bottom surface 30a of the pedestal portion 30 is formed to be approximately flush with the lowest portion of the curved pipe portion 14 (specifically, to protrude downward by 0.3 mm).

[0038] In the second embodiment, as in the first embodiment, the joint body 12 has a seat 30 formed on the bottom of the outer surface thereof, so that the joint body 12 can be stably placed on the placement surface. This provides excellent convenience.

[0039] In each of the above-described embodiments, a 90-degree elbow type electric fusion joint 10 in which the socket portions 16 extend in directions perpendicular to each other has been illustrated, but the electric fusion joint 10 may also be a 22.5-degree elbow type, a 45-degree elbow type, etc.

[0040] Furthermore, the specific values ​​and specific configurations such as dimensions given above are merely examples and can be changed as appropriate according to the needs of product specifications, etc. [Explanation of symbols]

[0041] 10... Electric fusion joint 12 ... Fitting body 14...Bent pipe section 16 ... Electric fusion socket 20...Power connection terminal 22 ... Indicator 30 ... Base 32 ... Gate remains

Claims

1. An elbow-type electric fusion joint, A joint body including a curved pipe portion extending laterally and an electric fusion socket portion extending from each of both ends of the curved pipe portion; and An electric fusion joint comprising a base portion formed on a bottom portion of an outer surface of the joint body and having a flat bottom surface in contact with a mounting surface.

2. The electric fusion joint according to claim 1 , comprising two of the pedestals formed at a predetermined distance from each other.

3. The electric fusion joint is formed by injection molding; 3. The electric fusion joint according to claim 2, wherein a gate mark generated at a gate position through which synthetic resin is poured into a mold during injection molding is formed between said two pedestal portions.

4. 3. The electric fusion joint according to claim 1, wherein the seat portion is formed on a bottom of an outer surface of the bent pipe portion.

5. 3. The electric fusion joint according to claim 1, wherein a bottom surface of the pedestal portion is formed flush or approximately flush with a lowest portion of the joint body.

6. The base portion is formed on a bottom of an outer surface of the curved pipe portion, 3. The electric fusion joint according to claim 1, wherein a bottom surface of the base portion is formed flush or approximately flush with a lowest portion of the electric fusion socket portion.

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