JPH06159582A - Connecting method for socket welding joint and thermoplastic resin tube and socket welding joint - Google Patents

Abstract

(57) [Summary] [Structure] The thermoplastic resin tube 2 was inserted into the socket welding joint 11 in joining the socket welding joint 11 having the heating element 13 embedded therein and the thermoplastic resin tube 2. After that, the lock ring 4 fitted to the outer surface of the thermoplastic resin tube 2 and provided with the tapered surface 42 on the outer peripheral surface is reduced in diameter by using the tapered surface 42, and thus the inner peripheral surface of the socket welding joint 11 is formed. And the outer peripheral surface of the thermoplastic resin tube 2 are formed to be substantially uniform, and then the heating element 13 of the socket welding joint 11 is heated to join the socket welding joint 11 and the thermoplastic resin tube 2. [Effect] Since the gap between the inner peripheral surface of the inlet welding joint 11 and the outer peripheral surface of the thermoplastic resin pipe 2 is formed substantially uniformly, the inlet weld joint 11 and the thermoplastic resin pipe 2 are firmly joined. .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for joining a socket welding joint and a thermoplastic resin pipe, and a socket welding joint used in this joining method.

[0002]

2. Description of the Related Art Conventionally, as a method for joining a socket welding joint having a heating element embedded in its inner peripheral portion and a thermoplastic resin tube,
As described in JP-A-4-19494,
Provide a tightening part at the tip of the socket welding joint, insert a thermoplastic resin tube into the socket welding joint, tighten the band with a tightening member such as a band at the tightening part, reduce the diameter of the tightening part, and heat the inner surface of the tightening part. A method is known in which the inlet welding joint and the thermoplastic resin pipe are fixed by bringing them into contact with the outer surface of the plastic resin pipe, and then the heating element is heated to weld and weld the inlet welding joint and the thermoplastic resin pipe. There is.

Further, as described in Japanese Patent Application Laid-Open No. 4-171392, a retaining member made of a shape memory alloy is provided in the socket welding joint to prevent it from slipping off and is inserted into the socket welding joint. There is known a method of welding and joining an inlet welding joint and a thermoplastic resin tube in a state where the thermoplastic resin tube is fixed.

[0004]

However, in the former method, that is, as described in Japanese Patent Application Laid-Open No. 4-19494, a tightening portion is provided at the tip of the socket welding joint, and the inside of the socket welding joint is provided. Insert the thermoplastic resin tube into the tube and tighten it with a tightening member such as a band at the tightening section to reduce the diameter of the tightening section and bring the inner surface of the tightening section into contact with the outer surface of the thermoplastic resin tube to make the socket weld joint and the thermoplastic resin tube. In the method of fixing and, and then heating the heating element to weld and join the socket welding joint and the thermoplastic resin tube, the thermoplastic resin tube is inserted at the time when the thermoplastic resin tube is inserted into the socket welding joint. Due to the weight of, the gap between the socket welding joint and the thermoplastic resin pipe is vertically different, the gap between the socket welding joint and the thermoplastic resin pipe is large above, and the gap between them is small below. In such a state, even when tightening with a tightening member such as a band in the tightening portion, the above-mentioned gap still has a vertical difference, and in such a state, the heating element is heated and the socket welding joint and the thermoplastic resin pipe are heated. Even if welding and welding are performed, the joining of the two becomes insufficient.

The latter method, that is, Japanese Patent Laid-Open No. 4-171
As described in Japanese Patent No. 392, in a state in which a retaining member made of a shape memory alloy is provided in the socket welding joint to prevent slipping off, and the thermoplastic resin tube inserted in the socket welding joint is fixed. Even in the method of welding and joining the socket welding joint and the thermoplastic resin pipe, a gap between the two is necessary in order to facilitate the insertion of the thermoplastic resin pipe into the socket welding joint. Has the same problem as in the former method, because the gap between the socket welding joint and the thermoplastic resin pipe is vertically different due to the weight of the thermoplastic resin pipe.

The present invention has been made in view of such problems in the conventional method for joining a mouthpiece welded joint and a thermoplastic resin pipe, and an object thereof is to solve the above problems. , Forming a gap between the inner peripheral surface of the inlet welding joint and the outer peripheral surface of another thermoplastic resin tube substantially uniformly, and then heating the heating element of the inlet weld joint to heat the inlet weld joint and the thermoplastic resin. It is to provide a method of joining a pipe.

[0007]

In order to achieve the above-mentioned object, in the method for joining a socket welding joint and a thermoplastic resin pipe according to the present invention as set forth in claim 1, a receiving element having a heating element embedded therein is provided. In joining the mouth welding joint and the thermoplastic resin pipe, after inserting the thermoplastic resin pipe into the mouth welding joint,
The outer circumference of the thermoplastic resin pipe and the outer peripheral surface of the thermoplastic resin pipe are fitted by shrinking the diameter of the lock ring that is fitted to the outer surface of the thermoplastic resin pipe and has a tapered surface on the outer peripheral surface by using the tapered surface to reduce the diameter. It is characterized in that the gap with the surface is formed substantially uniformly, and then the heating element of the socket welding joint is heated to join the socket welding joint and the thermoplastic resin pipe.

A socket welding joint according to a second aspect of the present invention is a socket welding joint used in the joining method according to the first aspect, and includes a lock ring provided near an end portion of the socket welding joint body. , And means for reducing the diameter of the lock ring by utilizing the tapered surface.

In the present invention, the socket welding joint may be provided at one end of the thermoplastic resin pipe as in the illustrated embodiment, or may be provided at at least one end of the thermoplastic resin joint.

In the present invention, since the lock ring to be used requires a large force and is elastically deformed by the force, it is desirable to use a metal such as a tough steel, but nylon or the like is preferable. A tough synthetic resin can also be used.

According to the method of joining the inlet welding joint and the thermoplastic resin pipe of the present invention as set forth in claim 1, when the inlet welding joint having the heating element embedded therein and the thermoplastic resin pipe are joined, After inserting the thermoplastic resin tube into the mouth welding joint, by fitting it to the outer surface of the thermoplastic resin tube and reducing the diameter of the lock ring provided with the tapered surface on the outer peripheral surface using the tapered surface, The gap between the inner peripheral surface of the socket welding joint and the outer peripheral surface of the thermoplastic resin tube is formed substantially uniformly, and then the heating element of the socket welding joint is heated to separate the socket welding joint and the thermoplastic resin tube. Since they are joined together, the inner surface of the mouthpiece welded joint and the outer surface of the thermoplastic resin pipe are evenly joined without any difference in the vertical direction, and both are firmly joined.

Further, in the socket welding joint of the present invention as defined in claim 2, the lock ring is reduced in diameter so that the gap between the inner peripheral surface of the socket welding joint and the outer peripheral surface of another thermoplastic resin pipe is substantially uniform. Therefore, the inner surface of the socket welding joint and the outer surface of the thermoplastic resin pipe are evenly joined in the vertical and horizontal directions without any difference in the vertical direction, and the two are firmly joined.

[0012]

Embodiments of the present invention will now be described with reference to the drawings. 1 to 3 are front cutaway views showing essential parts of an embodiment of the method of the present invention in the order of steps.

In these figures, reference numeral 11 designates a receptacle welding joint body provided at an end of the polyethylene pipe 1, the opening of which is a receptacle 1 for receiving a polyethylene pipe 2 which will be described later.
2 is formed. A heating element 13 formed of a heating wire such as a spiral nichrome wire is embedded inside the socket welding joint body 11, and both ends of the heating element 13 are provided at the socket welding joint body 11
The current-carrying terminal 14 is provided so as to project from the outer surface of the.
Although two energizing terminals 14 are provided, only one is illustrated because the two energizing terminals 14 are provided side by side on the same circumference of the socket welding joint body 11. A male screw 15 is engraved on the outer surface of the end of the welded joint main body 11, a polyethylene cap nut 3 is screwed into the male screw 15, and a steel lock ring 4 is provided inside the cap nut 3 to receive the cap. A welding joint is constructed.

The lock ring 4 is provided with a notch 41, and has a split ring shape so that the diameter of the lock ring 4 can be changed by the presence of the notch 41. A taper surface 42 is provided on the outer surface of the lock ring 4, an annular ridge 43 is provided on the inner surface thereof, and an inner peripheral corner portion is chamfered 44 for convenience of inserting the polyethylene pipe 2 described later. . An inner surface of the cap nut 3 is formed with an inverse taper surface 31 facing the inside of the socket 12 of the socket welding joint body 11, and the inverse taper surface 31 is in close contact with the taper surface 42 of the lock ring 4 so that the cap nut 3 To lock the lock ring 4 by screwing it into the male screw 15 on the outer surface of the end of the socket welding joint 11,
As a result, the inner surface of the lock ring 4 comes into pressure contact with the outer surface of the polyethylene pipe 2 inserted into the receptacle 12.

As shown in FIG. 2, the polyethylene pipe 2 to be joined with the polyethylene pipe 1 is inserted into the receiving port 12 of the socket welding joint provided at the end of the polyethylene pipe 1. Mouth 12
There is a slight gap between the inner surface of the polyethylene tube and the outer surface of the polyethylene tube 2.

In this state, the cap nut 3 is screwed in to reduce the diameter of the lock ring 4, and the inner surface of the lock ring 4 is brought into pressure contact with the outer surface of the polyethylene pipe 2 inserted into the receptacle 12.

As a result, the gap between the inner surface of the receiving port 12 and the outer surface of the polyethylene pipe 2 is uniform on the entire outer circumference of the polyethylene pipe 2. Then, when a power source (not shown) is connected to the energizing terminal 14 and electric power is supplied from the energizing terminal 14, the heating element 13 generates heat, and the inner surface of the receiving port 12 and the outer surface of the polyethylene pipe 2 in the vicinity are melted, as shown in FIG. So that both are welded together.

FIG. 5 is a cutaway front view of an essential part showing another example of the socket welding joint. In the socket welding joint shown in FIG. 5, the cap nut of the socket welding joint shown in FIGS. 1 to 3 is shown. Instead of using 3, the bolts 6 projecting from four places at equal intervals in the circumferential direction of the end face of the welding joint body 11a are inserted into the through holes 71 of the perforated disc 7 and screwed into the bolts 6. When the nut 61 is screwed in, the tapered surface 41 of the lock ring 4 that is in close contact with the reverse tapered surface 71 of the inner surface of the perforated disk 7 is pressed to reduce the diameter of the lock ring 4, so that the inner surface of the lock ring 4 is The outer surface of the polyethylene pipe 2 inserted into the receiving port 12a is pressure-contacted, and the gap between the inner surface of the receiving port 12a and the outer surface of the polyethylene pipe 2 is made uniform over the entire outer circumference of the polyethylene pipe 2. .

FIG. 6 is a cutaway front view of a main part showing still another example of the socket welding joint. In the socket welding joint shown in FIG. 6, a bag of the socket welding joint shown in FIGS. 1 to 3. Instead of using the nut 3 or the perforated disk 7 shown in FIG. 5, bolts 6b projecting from four locations at equal intervals in the circumferential direction of the end face of the welding joint body 11b are provided on the flange 7c of the flanged cylinder 7b. By inserting the bolt 6b into the through hole 71b provided in the portion 72b and screwing the bolt 6b, the flanged cylinder 7b presses the lock ring 4b that is in close contact with the reverse taper surface 15b provided on the end face of the joint body 11b, and the lock ring 4b. The tapered surface 41b of the lock ring 4 slides along the reverse tapered surface 15b to reduce the diameter of the lock ring 4, and as a result, the inner surface of the lock ring 4 is received by the socket 12b.
The outer surface of the polyethylene tube 2 to be inserted therein is pressure-contacted, and the gap between the inner surface of the receiving port 12b and the outer surface of the polyethylene tube 2 is made uniform over the entire outer circumference of the polyethylene tube 2.

FIG. 7 (a) is a cutaway front view of a main part showing still another example of the socket welding joint, and FIG. 7 (b) is a plan view thereof, showing the socket welding joint shown in FIG. Instead of using the cap nut 3 of the socket welding joint shown in FIG. 3, a cap nut 3c having cam grooves 32 provided at four locations at equal intervals in the circumferential direction is used, and the cap nut 3c is rotated. By moving, the trochanter 15 projectingly provided on the joint main body 11c rolls from the inlet portion 321 in the cam groove 32 to the inner portion 322, and as a result,
The cap nut 3c is pulled toward the joint body 11c, and the reverse taper surface 31c of the cap nut 3c presses the taper surface 41c of the lock ring 4c.
As a result, the inner surface of the lock ring 4c presses against the outer surface of the polyethylene pipe 2 inserted into the receiving port 12c, and the gap between the inner surface of the receiving port 12c and the outer surface of the polyethylene pipe 2 becomes a polyethylene pipe. 2 is uniform on the entire outer circumference. As the trochanter 15, it is possible to use a current-carrying terminal provided at two opposite positions on the same circumference, or it is possible to use a projection integrally provided on the joint body 11c.

FIG. 8 (a) is a cutaway front view of a main part showing still another example of the socket welding joint, and FIG. 8 (b) is a sectional view taken along line BB of FIG. 8 (a). In the socket welding joint shown, instead of using the cap nut 3 of the socket welding joint shown in FIGS. 1 to 3, a cap nut 3d provided with a projection rotor 33d is used, and the cap nut 3d is rotated. As a result, the trochanter 33d rubs against the cam surface of the projection 16 provided on the joint body 11d, and as a result, the cap nut 3d is pulled toward the joint body 11d and the reverse taper surface 31d of the cap nut 3d is pulled. Is the taper surface 4 of the lock ring 4d
1d is pressed to reduce the diameter of the lock ring 4d, and as a result,
The inner surface of the lock ring 4d press-contacts the outer surface of the polyethylene pipe 2 inserted into the receiving port 12d, and the gap between the inner surface of the receiving port 12d and the outer surface of the polyethylene pipe 2 is the polyethylene pipe 2
Is uniform over the entire outer circumference of.

[0022]

According to the method of joining the socket welding joint and the thermoplastic resin pipe of the present invention as set forth in claim 1, the gap between the inner peripheral surface of the socket welding joint and the outer peripheral surface of another thermoplastic resin tube is provided. Is formed substantially uniformly, and thereafter, the heating element of the inlet welding joint is heated to join the inlet welding joint and the thermoplastic resin pipe, so that the inner surface of the inlet welding joint and the thermoplastic resin pipe are There is no difference between the outer surface and the outer surface, and they are evenly bonded, and both are firmly bonded.

Further, in the socket-welding joint of the present invention as defined in claim 2, the diameter of the lock ring is reduced so that the gap between the inner peripheral surface of the socket-welding joint and the outer peripheral surface of another thermoplastic resin pipe is substantially uniform. Since it is formed in the above, the inner surface of the socket welding joint and the outer surface of the thermoplastic resin pipe are evenly joined without any difference in the vertical direction, and the two are firmly joined.

[Brief description of drawings]

FIG. 1 is a cutaway front view of an essential part showing an embodiment of a method of the present invention.

FIG. 2 is a cutaway front view of an essential part showing an embodiment of the method of the present invention.

FIG. 3 is a cutaway front view of an essential part showing an embodiment of the method of the present invention.

FIG. 4 is an explanatory view showing an example of a lock ring used for a socket welding joint.

FIG. 5 is a cutaway front view of an essential part showing another example of the socket welding joint.

FIG. 6 is a cutaway front view of a main part showing still another example of the socket welding joint.

FIG. 7A is a cutaway front view of a main part showing still another example of the socket welding joint. (B) The principal part top view.

FIG. 8A is a cutaway front view of a main part showing still another example of the socket welding joint. (B) is sectional drawing in the BB line of (a) figure.

[Explanation of symbols]

 11 Receptacle Welding Joint 12 Receptacle 13 Heating Element 2 Polyethylene Pipe 3 Cap Nut 4 Lock Ring

Claims (2)

[Claims] 1. When joining a socket welding joint having a heating element embedded therein and a thermoplastic resin pipe, after inserting the thermoplastic resin tube into the socket welding joint, the thermoplastic resin pipe is attached to the outer surface of the thermoplastic resin pipe. By fitting the lock ring, which has a tapered surface on the outer peripheral surface, to reduce the diameter using the tapered surface, the gap between the inner peripheral surface of the socket welding joint and the outer peripheral surface of the thermoplastic resin pipe is substantially reduced. A method for joining a socket-welding joint and a thermoplastic resin tube, characterized by uniformly forming and thereafter heating a heating element of the socket-welding joint to join the socket-welding joint and the thermoplastic resin pipe. 2. A lock ring provided near the end of the socket welding joint body, and means for reducing the diameter of the lock ring by utilizing a tapered surface.
A socket welding joint for use in the joining method described.