JP2014031840A - Electric fusion joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel electric fusion joint capable of surely performing fusion joining between a pipe and joint, with good workability.SOLUTION: An electric fusion joint 10 has a socket 16, and is integrally provided with a half-split clamp part 28 outward a joint shaft direction with respect to the socket 16 by a connection part 30 extending in the joint shaft direction from an opening end 26 of the socket 16. When a pipe is joined, a pipe 14 is inserted into the socket 16 through the clamp part 28, the pipe 14 is clamped by the clamp part 28, and in such a state, electrification is performed with a current-carrying terminal 20. Consequently, heat is generated with a heating wire 18, and the joint 10 and the pipe 14 are fused.

Description

  The present invention relates to an electrofusion joint, and more particularly, to an electrofusion joint including a clamp portion for fixing a joint body and a tube during fusion.

  Patent Document 1 discloses this type of electric fusion joint.

  In the electric fusion joint of Patent Document 1, a tightening portion is provided on the receiving end side from the region where the heating wire is provided. Then, the pipe is inserted into the joint receiving port, and the fastening portion is fastened with a fastening member such as an insulation lock tie (trade name, the same shall apply hereinafter), thereby fixing the pipe and the joint. The pipe and the joint are fused and joined by energizing the hot wire.

In the electric fusion joint of Patent Document 1, the working space is small, and it is not necessary to remove the fastening member, so that the fusion part is not yet cooled as in the case of using another clamping member. There is no fear of releasing the fixed state between the pipe and the joint, and the pipe can be securely connected to the joint.
JP-A-4-19494 [F16L 47/02]

  In the electric fusion joint of Patent Document 1, it is necessary to insert, for example, a band portion of an insulation lock tie as a tightening member around the entire periphery of the tightening portion and then insert it into a flat hole in the locking component. Not very good.

  Therefore, the main object of the present invention is to provide a novel electrofusion joint.

  Another object of the present invention is to provide an electric fusion joint capable of reliably fusing a pipe and a joint with good workability.

  The present invention employs the following configuration in order to solve the above problems. Note that reference numerals in parentheses, supplementary explanations, and the like indicate correspondence relationships with embodiments described later to help understanding of the present invention, and do not limit the present invention in any way.

  According to a first aspect of the present invention, there is provided a joint main body having a receptacle, a joint main body, and an electric power provided on the inner surface of the receptacle sandwiched between the first cold zone on the opening end side and the second cold zone on the back side. A pipe provided in the joint body, connected to the opening end of the receiving port by a connection terminal for supplying current to the heating wire, and a connecting portion, and provided in the joint axial direction from the opening end and inserted into the receiving port An electric fusion joint, wherein the first portion in the circumferential direction is formed with a first thickness, and the second portion is formed with a second thickness that is thinner than the first thickness. is there.

  In the first invention, the electric fusion joint (10: reference numeral indicating a corresponding part in the embodiment; the same applies hereinafter) includes a hollow cylindrical joint body (12), and the joint of the joint body (12) At least one side in the axial direction is formed as a receiving port (16), and a clamp portion (28) is connected to an open end (26) of the receiving port (16) via a connecting portion (30). Therefore, the clamp portion (28) is disposed outside the open end (26) in the joint axial direction. As an example, the clamp part (28) is integrally formed by injection molding together with the connecting part (30) and the joint body (12). And the 1st part (for example, center part (30a)) of the circumferential direction is formed by 1st thickness, and the 2nd part (for example, right and left part (30b) which pinches | interposes a center part) is 1st thickness in a connection part. It is formed with a thinner second wall thickness.

  According to the first invention, since the clamp part (28) is provided integrally with the joint body (12), the joint can be clamped to the pipe with the clamp part (28), and a separate clamping device is prepared. do not have to. Therefore, workability at the time of electrofusion is improved.

  Moreover, since the clamp part (28) is provided outside the receiving opening end (26), the deformation stress when the pipe is clamped by the clamp part (28) causes the joint body (12), particularly the heating wire (18) part. It can be prevented from being transmitted to (fused part). Therefore, deformation of the joint body (12) at the portion of the heating wire due to the stress at the time of clamping can be suppressed as much as possible, and occurrence of poor fusion due to deformation of the body can be prevented.

  Further, since the thick portion (first portion) and the thin portion (second portion) are formed in the circumferential length (width direction) of the connecting portion, the stress at the time of clamping is melted. It is possible to further suppress the transmission to the landing part. For example, when the connection part (30) is formed with the same thickness in the entire circumferential length, the deformation stress at the time of clamping at the clamp part (28) is transmitted as it is. Since the connecting part easily deforms in the part (second part) and absorbs stress by the deformation, the propagation of stress from the clamp part (28) is reduced, and the tube (14) is clamped by the clamp part (28). The deformation of the joint body can be reduced.

  That is, according to the first aspect of the invention, the clamp portion is arranged on the outer side in the joint axial direction of the joint body by the connecting portion, so that the workability of the fusion is improved and the fusion portion can be deformed. This makes it possible to prevent the damage and secure the bonding.

  A second invention is an electric fusion joint according to the first invention, wherein the clamp portion has opposing portions facing each other, and the tube is fixed so that the opposing portions are brought close to each other.

    In the second invention, the clamp portions (28: 28a, 28b) have opposing portions (32a, 32b) facing each other. Then, for example, a through hole is formed in the facing portion, and a tapping screw is screwed in to fix the tube so that the facing portion approaches.

    According to the second invention, since the tube can be clamped only by screwing, for example, the workability is further improved.

    A third invention is an electric fusion joint according to the first or second invention, wherein the first thickness of the first portion is thinner than the thickness of the receiving port.

  In the third aspect of the invention, the first thickness of the first portion (30a) of the connecting portion (30) is made smaller than the thickness of the receiving opening end (26), so that it is received when the clamp portion (28) is clamped. The stress transmitted to the mouth can be further reduced, and more reliable fusion bonding is possible.

    A fourth invention is according to the third invention, wherein the inner surfaces of the first portion and the second portion of the connecting portion are in the same plane as the inner surface of the receiving port, and the outer surface of the first portion is inside the outer surface of the receiving port. It is an electric fusion joint.

  In the fourth invention, in order to make the first thickness of the first portion of the connecting portion (30) smaller than the thickness (T3) of the receiving port (16), the first portion (30a) and Since the inner surface of the two parts (30b) should be flush with the inner surface of the receiving port, the outer surface of the first part (30a) of the connecting portion (30) is more than the outer surface of the receiving port (16). The inner surface side is formed, and a part of the outer surface of the connecting portion and the outer surface of the receiving port are formed with a step.

  According to the fourth aspect of the present invention, the outer surface of the first portion (30a) of the connecting portion (30) and the outer surface of the receiving port (16) are stepped so that the former is lower than the latter. When the portion (28) is clamped, the stress transmitted from the outer surface side of a part of the clamp portion to the outer surface of the receiving port is blocked by the step. Therefore, the deformation of the joint body (12) when the pipe (14) is clamped by the clamp part (28) can be further reduced.

  According to this invention, the pipe and the joint can be fusion-bonded with good workability by inserting the pipe into the receiving port and fixing it with the clamp portion. In addition, since the clamp portion is arranged outwardly in the joint axial direction of the joint body by the connecting portion, the workability of the fusion is improved and the deformation of the fusion portion is prevented as much as possible to ensure reliable joining. It becomes possible.

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

FIG. 1 is a schematic perspective view showing a state in which pipes are connected using a socket-type electrofusion joint according to an embodiment of the present invention. FIG. 2 is a plan view of the socket type electric fusion joint shown in FIG. 3 is a bottom view of the socket-type electrofusion joint shown in FIG. FIG. 4 is a partially broken front view of the socket-type electrofusion joint shown in FIG. FIG. 5 is an end view of the socket-side electrofusion joint shown in FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 4, showing the connecting portion in the embodiment of FIG. FIG. 7 is a partial perspective view particularly showing the connecting portion in an easily understandable manner. FIG. 8 is a partially broken front view of a socket-type electrofusion joint according to another embodiment of the present invention. FIG. 9 is a cross-sectional view corresponding to FIG. 6, showing the connecting portion in the embodiment of FIG.

  Referring to FIG. 1, a socket-type electrofusion joint (hereinafter, simply referred to as “joint”) 10 of this embodiment includes a substantially hollow cylindrical main body 12 made of a synthetic resin such as polyethylene or polybutene. In addition, both ends of the body 12 are formed as receptacles 16 for receiving the tubes 14. In this embodiment, the joint main body 12 has a nominal diameter of 20, but the size of the main body 12 is arbitrary such as a nominal diameter of 20, 25, 30, 40, 50.

  In the vicinity of the inner surface of the receiving port 16, as can be seen particularly from FIG. 4, heating heating wires 18 are embedded, and both ends of the heating wires 18 are provided so as to protrude from the surface of the main body 12. Connected to. The energizing terminal 20 is arranged in a guard 22 having a cylindrical wall around it and having an upper end opened. An indicator 24 is provided on the surface of the main body 12 on the back side of each energizing terminal 20. The indicator 24 has a thin cylindrical hole extending from the vicinity of the heating wire 18 inside the main body 12 to the surface of the main body 12 as well understood from FIG. 4. As is well known, the heating wire 18 This is to indicate the progress of fusion depending on whether or not the resin of the main body 12 melted in the vicinity rises to the surface due to thermal expansion.

  As is well known, both sides of the heating wire 18 form a so-called cold zone. That is, the heating wire 18 is sandwiched between the cold zones on both sides and embedded in the joint body 12. However, it may be exposed on the inner surface of the joint. Even if the heating wire 18 is energized from the energizing terminal 20, the resin in the cold zone does not melt. Therefore, the cold zone serves to confine the resin of the joint body 12 and the pipe 14 melted by the molten heating wire 18 and to ensure the fusion.

  As shown in FIG. 4, the joint axial length of the heating wire 18 is L1, and the joint axial length of the first cold zone on the opening end 26 side of the receiving port 16 among the cold zones on both sides is L2. When the joint axial length of the second cold zone on the back side from the heating wire 18 is L3, in the joint 10 having the nominal diameter 20 of the embodiment, L1, L2, and L3 are 14.4 mm, 12. They were 9 mm and 11.7 mm. That is, the relationship is L1> L2> L3. However, the dimensions L1, L2, and L3 change when the nominal diameter changes, but the relationship of L1> L2> L3 is the same even when the nominal diameter changes.

  In this embodiment, a clamp portion 28 is provided integrally with the receiving port 16 on the outer side of the joint 10, that is, the joint 12 of the main body 12 from the opening end 26 of the receiving port 16. In this embodiment, the clamp portion 28 has a first clamp portion 28a and a second clamp portion 28b which are divided into upper and lower halves, as can be seen particularly well from FIG. And in order to connect the 1st clamp part 28a and the receiving opening end 26, and to connect the 2nd clamping part 28b and the receiving opening end 26, especially a connection part which can understand well from FIG. 6 and FIG. 30 is formed. In other words, the clamp portion 28 is disposed on the outer side in the joint axial direction of the opening end 26 by the connecting portion 30. Therefore, in this embodiment, the energizing terminal 20 is provided in the receiving port 16, that is, the joint body 12, and the clamp portion 28 is provided at a distance from the energizing terminal 20.

  In this embodiment, in the case of a joint having a nominal diameter 20, the width of the clamp portion 28, that is, the length in the joint axial direction is set to 11 mm. However, in the experiments by the inventors, the width of the clamp portion 28 is changed even if the nominal diameter is changed. There was no need. That is, the width of the clamp portion 28 is the same regardless of the size of the nominal diameter.

  However, the specific numerical value (11 mm) of the width of the clamp part 28 can be changed as appropriate, and of course, the width of the clamp part 28 can be changed according to the size of the nominal diameter.

  Opposing portions 32a and 32b facing each other are formed at both ends of the first clamp portion 28a and the second clamp portion 28b, respectively. Therefore, in the clamp portion 28 of this embodiment, the tube 14 inserted into the receiving port 16 is clamped as shown in FIG. 1 by bringing the opposing portions 32a and 32b closer to each other.

  In this embodiment, as means for displacing the facing portions 32a and 32b toward each other, a tapping screw 36 (FIG. 1) that is screwed into the through holes 34a and 34b formed in the facing portions 32a and 32b. FIG. 2) is used. That is, by inserting and turning the tapping screw 36 that fits the through holes 34a and 34b from the upper ends of the through holes 34a formed in the facing portions 32a and 32b, as shown in FIG. It is screwed into the hole 34b. Accordingly, the facing portion 32a is displaced downward and the facing portion 32b is displaced upward, so that the facing portions 32a and 32b approach each other. Therefore, in this embodiment, the pipe 14 (FIG. 1) can be clamped by the clamp portion 28, that is, the first clamp portion 28a and the second clamp portion 28b, simply by screwing the screw 36, so that the workability at the time of clamping is good. .

  However, the means for displacing the facing portions 32a and 32b in a direction approaching each other may be other than the screw 36 of the embodiment. For example, even when a wire or a SUS band is inserted into the through holes 34a and 34b and tightened, the tube 14 can be firmly clamped by the first clamp portion 28a and the second clamp portion 28b. it can.

  As described above, in order to dispose the clamp portion 28 outward from the receiving opening end 26, in this embodiment, the connecting portion 30 as particularly well understood from FIGS. 6 and 7 is used. That is, the connection part 30 connects the 1st clamp part 28a and the 2nd clamp part 28b with the receptacle opening end 26, respectively. As can be seen from FIGS. 4 and 5 in particular, each connecting portion 30 has the same or substantially the same circumferential length (arc length) as the corresponding first clamp portions 28a and 28b. However, the lengths are not necessarily the same.

  In this embodiment, since the clamp portion 28 is provided outside the opening end 26 of the receiving port 16, the deformation stress when the tube 14 (FIG. 1) is clamped by the clamp portion 28 is particularly large in the portion of the heating wire 18 of the main body 12. It is possible to suppress as much as possible that the joint main body 12 is deformed in that portion (portion indicated by L1 in FIG. 4).

  The energizing terminal 20 for energizing the heating wire 18 is basically provided in the vicinity of the end of the heating wire 18, so that the resin on the inner surface of the receiving port 16 is somewhat affected by the heating by the heating wire 18 in the vicinity of the energizing terminal 20. It melts and the surrounding strength decreases. Therefore, if the clamp portion 28 as in the embodiment is provided near the energizing terminal 20, the resin may flow out from the portion where the tube 14 is fastened by the clamp portion 28. It will cause poor wear.

  On the other hand, in the embodiment, since the energizing terminal 20 is provided on the main body 12 and the clamp portion 28 is provided outside the main body 12, there is no possibility that the molten resin flows out at the clamp portion 28. The portion 28 can clamp the tube 14 securely.

  Each connecting portion 30 is formed of a central portion 30a in the circumferential direction and left and right portions 30b sandwiching the central portion 30a, as can be seen from FIGS. The central portion 30a and the left and right portions 30b have different thicknesses, and the central portion 30a is thicker than the left and right portions 30b. As described above, the reason why the left and right portions 30b are formed thinner than the central portion 30a is that when the tube 14 (FIG. 1) is clamped using the clamp portion 28, the above-described screw 36 is tightened at the clamp portion 28. Accordingly, the stress transmitted to the joint body 14 is made as small as possible.

  That is, when the connection portion 30 is formed to have the same thickness as the central portion 30a in the entire length in the circumferential direction, the deformation stress at the time of tightening the screw 36 at the clamp portion 28 is transmitted as it is, and the above-described case of the joint body 12 Will increase the deformation. In contrast, in the embodiment, since the left and right portions 30b are formed thin, the connecting portion 30 is easily deformed by the left and right portions 30b and absorbs stress by the deformation. The deformation of the joint body 12 when clamped can be reduced.

  However, if the entire connecting portion 30 is thinned, the connecting portion 30 becomes too flexible, and the clamp portion 28 and the receiving opening end 26 cannot be stably connected. Therefore, at least a part of the connecting portion 30 needs to be formed thick. That is, forming the connecting portion 30 with the thick portion and the thin portion has the first function of stably connecting the clamp portion 28 and the receiving opening end 26, and the tube 14 is clamped by the clamp portion 28. This is important for satisfying the second function of suppressing the transmission of deformation stress to the joint body 12 when it is done.

  Thus, in this embodiment, when the thickness of the connecting portion 30 is T1, and the thickness of the left and right portions 30b is T2, T1> T2. However, T1 <T2 may be set, but in that case, there is a possibility that a mold for injection molding the joint 10 becomes complicated.

  A further feature of this embodiment is that the thickness T1 of the central portion 30a of the connecting portion 30 is smaller than the thickness T3 of the receiving opening 26. As shown in FIG. 1, the tube 14 is inserted into the receiving port 16 from the opening end 26 through the clamp portion 28 and then clamped by the clamp portion 28. The inner surfaces of must be in the same plane. That is, the inner diameter of the clamp portion 28 and the inner diameter of the receiving port 16 are the same. Therefore, as in this embodiment, when the thickness T1 of the central portion 30a of the connecting portion 30 is to be made smaller than the thickness T3 of the receiving opening 26, the outer surface of the connecting portion 30 is on the inner side of the outer surface of the receiving port 16. It is necessary to. That is, the outer surface of the central portion 30a of the connecting portion 30 and the outer surface of the receiving port 16 are formed with a step 38 as shown in FIG. However, in FIG. 7, the step 38 is shown as an inclined surface, but if the changes in the thicknesses T3 and T1 are made gentle, it becomes an inclined surface, and if it changes suddenly from the thickness T3 to T1, it becomes a step. Here, “step” is used as a term encompassing both.

  As described above, when the thickness T1 of the central portion 30a of the connecting portion 30 is made thinner than the thickness T3 of the receiving port 16, the above-described second function of the connecting portion 30 can be more effectively exhibited. That is, since the outer surface of the central portion 30a of the connecting portion 30 and the outer surface of the opening end 26 of the receiving port 16 form the step 38 (FIG. 7) so that the former is lower than the latter, the outer surface of the central portion 30a. The deformation stress transmitted from the side to the outer surface of the receiving opening 26 is blocked by the step 38. Therefore, the deformation of the joint body 12 when the tube 14 is clamped by the clamp portion 28 can be further reduced.

  However, the thickness T1 of the central portion 30a of the connecting portion 30 and the thickness T3 of the receiving port 16 may be the same. Examples of this are shown in FIGS. That is, the embodiment of FIGS. 8 and 9 is the same as the above-described embodiment except that the thickness T1 of the central portion 30a of the connecting portion 30 and the thickness T3 of the receiving port 16 are the same. is there.

  In the above-described embodiment, the socket type electric fusion joint has been described as an example. However, the present invention is not limited to the socket type, and can be applied to an electric fusion joint of any shape such as an elbow type.

  Moreover, in the above-mentioned Example, the clamp part 28 was made into the up-and-down halved structure, and has arrange | positioned the 1st clamp part 28a on the upper side, and the 2nd clamp part 28b on the lower side. However, such a half direction is not limited to the vertical direction, and may be the horizontal direction. In the case of the halved structure in the left-right direction, the first clamp portion 28a and the second clamp portion 28b are arranged on the left and right.

  In addition, instead of the half structure, for example, a "C" -shaped clamp in which the corresponding one ends of the first clamp portion 28a and the second clamp portion 28b are continuous and the corresponding other ends face each other. May be adopted. In that case, the other ends facing each other are clamped by displacing them in a direction approaching each other, for example, with a screw. In the case of a screw, it can be clamped by tightening only one screw.

  Note that the specific numerical values such as the diameter, width, and height described above are merely examples, and can be changed as appropriate.

10 ... Electric fusion joint (joint)
DESCRIPTION OF SYMBOLS 12 ... Main body 14 ... Pipe | tube 16 ... Receptacle 18 ... Heating wire 20 ... Current supply terminal 26 ... Open end 28 ... Clamp part 28a ... 1st clamp part 28b ... 2nd clamp part 30 ... Connection part 30a ... Center part 30b ... Left-right part 32a, 32b ... Opposite parts 34a, 34b ... Through hole 36 ... Tapping screw 38 ... Step

Claims (4)

A joint body having a receptacle,
A heating wire provided on the inner surface of the receptacle provided between the first cold zone on the open end side of the receptacle and the second cold zone on the back side provided on the joint body;
An energizing terminal for energizing the heating wire, provided on the joint body, and connected to the opening end of the receiving port by a connecting portion, provided on the outer side in the joint axial direction from the opening end, and connected to the receiving port. It has a clamp part to fix the inserted tube,
The connecting portion is an electrofusion joint in which a first portion in the circumferential direction is formed with a first thickness, and a second portion is formed with a second thickness that is thinner than the first thickness.   The clamp part has an opposing part which counters mutually, and fixes the pipe so that the opposing part may be approached, An electric fusion joint.   The electrofusion joint according to claim 1 or 2, wherein the first thickness of the first portion is thinner than the thickness of the receiving port.   The inner surface of the said 1st part of the said connection part and the 2nd part is in the same surface as the inner surface of the said receiving port, The outer surface of the said 1st part becomes inner side than the outer surface of the said receiving port. Electric fusion joint.

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