JPH1113983A - Electric welding joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the movement of a resin pipe or a joint during welding and to strongly weld both uniformly by forming an unnotched part made by notching a proper circumference in the connecting end of a joint main body and fastening the resin pipe inserted into the joint main body to the unnotched part by using a fastening tool. SOLUTION: A notched part 2e is formed by notching a specified length from the end surface of a joint main body 2 having a buried electric heat generation element by roughly half of a circumference, and locking parts 2c are formed in both end parts of an unnotched part 2b. On the other hand, annular parts 4 are fixed to both end parts of a pressing tool 3 and a cam 5 is fixed to one thereof. Cut joints are worked on the inner peripheral surfaces of the unnotched part 2b and the pressing tool 3. When the pipe end of a resin pipe 6 is inserted into the joint main body 2 and welded, after the resin pipe 6 is inserted into the connecting end of the joint main body 2, this resin pipe 6 is fastened to the unnotched part 2b by using the pressing tool 3 and then the resin pipe 6 is firmly fixed to the joint main body 2. In this state, by conducting electricity to the electric heat generation element, both are uniformly and strongly welded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrofusion joint for electrofusion with a thermoplastic resin tube.

[0002]

2. Description of the Related Art There are various types of pipe joints to be connected to a thermoplastic resin pipe. An electric heating element such as a nichrome wire is embedded in an inner surface of the fitting, a thermoplastic resin pipe is inserted, and electricity is supplied to the electric heating element. Electrofusion joints that generate heat and fuse the joint to the pipe are widely used.

However, there is naturally an allowable error in the outer diameter of the connection end of the thermoplastic resin pipe, and therefore the inner diameter of the inner surface of the joint of the electrofusion joint is determined to be large, and further processed to this size. Tolerance is added. For this reason, when the resin tube is inserted into the electrofusion joint, a gap is generated between the tube and the joint, and the tube and the joint are not kept coaxial or the positioning in the axial direction is uncertain.

In this state, when the electric heating element is energized to heat and melt the inner surface of the joint of the electrofusion joint and the outer surface of the resin tube facing the same, there is no gap between the inner surface of the joint and the outer surface of the resin tube. Due to the uniformity, the melting on the outer surface of the resin tube becomes uneven, and when the molten resin is cooled and solidified, poor fusion may occur. Further, before the molten resin is cooled to a temperature lower than the crystallization temperature, the joint or the resin pipe may move due to the pressure or external force of the molten resin, and the connection interface may move to make it impossible to perform a firm fusion connection.

In order to prevent such a fusion defect, FIG.
In many cases, welding is performed using a welding tool 31 as shown in FIG. In FIG. 10, reference numeral 32 denotes an electric fusion joint,
Numerals 3 and 34 are thermoplastic resin tubes.

[0006] The fusing tool described above has many problems as described below.
As shown in JP-A-5083 and JP-A-7-251456, a wedge is inserted between the joint inner diameter and the outer surface of the resin tube at the connection end of the electric fusion joint to insert the resin tube into the electric fusion joint. As shown in the fixing method and Japanese Patent Application Laid-Open No. 7-329186, a female screw is provided on the inner peripheral surface of the electric fusion joint, and a male screw processed at the tip of the resin pipe is screwed into the female screw to perform electric fusion. A method of fixing a resin pipe to a joint has been proposed.

[0007]

As described above, when using the welding tools 31 as shown in FIG. 10 in order to prevent defective welding, these tools are used for each size of the resin pipe. You need to prepare. Also, it takes a considerable amount of time to cool to a temperature below the crystallization temperature at which sufficient adhesive strength can be obtained, and during this time, the tool for the fusion work cannot be removed from the resin pipe, so proceed to the next step. Disappears. For this purpose, it is necessary to prepare a plurality of tools for the same size of the resin pipe. Therefore, the method using the welding tool is expensive.

Further, the method using the welding tool is inconvenient to use in a narrow working space, not only requires a lot of man-hours for mounting work, but also takes time and effort to collect the tool after cooling. Many man-hours are required for piping work.

Next, as shown in JP-A-6-265083 and JP-A-7-251456, a wedge is inserted between the inner diameter of the joint and the outer surface of the resin pipe at the connection end of the electric fusion joint. In the method of fixing the resin tube to the electric fusion joint, the former uses a retaining member having a tapered stiffener portion as a wedge, and the retaining member has a peculiar shape and is expensive. is there. Further, in the latter, a plurality of wedges are individually driven and inserted into the same circumferential portion, and a plurality of wedges are formed so that a gap between the electric fusion joint and the resin pipe is equalized. Inserting is a very cumbersome task, especially in narrow workspaces.

[0010] Further, as shown in JP-A-7-329186, a female screw is provided on the inner peripheral surface of the electrofusion joint,
In the method of fixing the resin pipe to the electrofusion joint by screwing the external thread processed at the tip of the resin pipe into this, the external thread must be processed after cutting the resin pipe of the length according to the piping site Not only that, work on site becomes troublesome.

The problem to be solved by the present invention is the above-mentioned various problems when performing electric fusion splicing with a resin pipe using various conventional electric fusion joints.

[0012]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object, and has a notch formed by cutting a predetermined length from an end face of a connection end of a joint body by an appropriate circumference. The resin tube inserted into the connection end of the joint main body was formed with the remaining portion, and the resin tube was tightened to the remaining portion of the notch using a fastener at the above-mentioned notch portion, so that the resin tube was tightened to the joint main body.

In this case, the fastening tool is a substantially semicircular holding tool having an inner diameter substantially the same as the connection end of the joint body, and the holding tool and the remaining notch are connected at both ends thereof. Then, it is preferable that the resin pipe be fastened to the joint body.

[0014] Further, the connecting ring-shaped parts mounted on either end of the holding member and the remaining part of the notch are engaged with the locking parts provided on the other end, respectively. It is preferable that the presser is strongly pulled toward the above-mentioned notch remaining portion by the action of the cam mounted on one or both of the above, so that the resin pipe is fastened to the joint body.

Alternatively, the fastener may be substantially U-shaped.
A clamp spring plate having a U-shape, and inserting both ends of the clamp spring plate into guide holes provided outside the both end portions of the notch remaining portion, with the arc-shaped portion of the spring plate facing the above-mentioned notch remaining portion. Then, when the clamp spring plate is pressed toward the outer peripheral surface of the remaining portion by notching the arc-shaped portion, the portion of the clamp spring plate protruding from the above guide hole attempts to return to its original shape. The resin tube was pushed toward the above-mentioned notch remaining portion by a force to tighten the resin tube to the joint body.

[0016] With the above-described structure, after the resin pipe to be fused to the joint body is inserted into the connection end of the joint body, this resin pipe is notched and the remaining part of the notch is used to hold a holding member or a clamping member for the clamp spring plate. And the resin tube is fastened to the joint body by using it, so that the resin tube and the joint do not move due to the pressure or external force of the molten resin at the time of fusion, and the two are uniformly and firmly fused and connected. be able to.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the electrofusion joint according to the present invention will be described. FIG. 1 is a perspective partial external view showing an embodiment of the electrofusion joint of the present invention, and FIG.
FIG. 2 is a partial longitudinal sectional view showing a state where a resin pipe is inserted into the joint main body shown in FIG. 1 and tightened by a fastener. 3 is a side view showing a state in which a resin tube is inserted into the joint main body in FIG. 1, and FIG. 4 is a side view showing a state in which a holding member is mounted and tightened from the state in FIG.

1 to 4, reference numeral 1 denotes an electric fusion joint, 2 denotes a joint body, 3 denotes a holding member, 4 denotes an annular portion, 5 denotes a cam, 6 denotes a resin tube, and 7 denotes an electric heating element. A predetermined length is cut out from the end face 2a of the joint main body 2 by substantially a semicircle to form a cutout portion 2e.
Form c. A notch 2d is provided between the remaining portion 2b and a portion of the joint body 2 where the notch is not formed. An annular portion 4 is attached to both ends of the holding member 3, and a cam 5 is attached to one of the annular portions. Also, the inner peripheral surface of the notch remaining portion 2b and the inner peripheral surface of the retainer 3 are provided with notches having a sawtooth cross section.

FIG. 5 is a perspective partial external view showing another embodiment of the electrofusion joint of the present invention, and FIG. 6 is a clamp spring plate in which a resin tube is inserted into the joint body shown in FIG. FIG. 3 is a partial vertical cross-sectional view showing a tightened state. FIG.
FIG. 6 is a side view showing a state where a resin tube is inserted into the joint main body shown in FIG. 5 and tightened at both leg portions of a clamp spring plate.

5 to 7, reference numeral 11 denotes an electrofusion joint, 12 denotes a joint body, 13 denotes a spring plate for clamping, 14 denotes a resin tube, and 15 denotes an electric heating element. A predetermined length is cut out by substantially a semicircle to form a cutout portion 12e, and guide holes 12c are provided outside both ends of the cutout remaining portion 12b. Both ends of the clamp spring plate 13 are formed in the guide holes 12c. As shown in FIG. 5, and as shown by a two-dot chain line in FIG. 7, the arc-shaped portion 13a is inserted with the notch remaining portion 12b side. When the arc-shaped portion 13a is pressed against the outer peripheral surface of the notch remaining portion 12b, the portion protruding from the guide hole 12c tends to return to its unique shape when the arc-shaped portion 13a is pressed toward the outer peripheral surface of the notch remaining portion 12b. As shown in (1), the resin pipe 14 is formed so as to be pressed against the notch remaining portion 12b of the joint body 12.

In the joint body 12, as in the embodiment shown in FIGS. 1 to 4, a cut 12d is provided, and a notch having a saw-tooth cross section is formed on the inner peripheral surface of the notch remaining portion 12b. It has been given.

FIG. 8 is a perspective partial external view showing still another embodiment of the electrofusion joint of the present invention. FIG. 9 is a perspective view showing a clamp spring by inserting a resin tube into the joint main body shown in FIG. It is a side view which shows the state clamped by the arc-shaped part of a board.

In FIGS. 8 and 9, reference numeral 16 denotes an electrofusion joint, and the joint body 12 is exactly the same as the joint body 12 in the embodiment shown in FIGS. Reference numeral 17 denotes a clamp spring plate, which is a guide hole 1 of the joint body 12.
As shown in FIG. 8 and in FIG. 9, the two ends of the clamping spring plate 17 are inserted with the arc-shaped portion 17a notched as shown in FIG. As shown in FIG. 9, when the arc-shaped portion 17 a is pressed toward the notch, the spring plate 17 for clamping uses the elastic force of the portion protruding from the guide hole 12 c to return to its unique shape, as shown in FIG. 9. At the protruding portion, the notch remaining portion 1 of the joint body 12 is formed.
2b, the arc-shaped portion 17a is moved to the resin pipe 14
Is pressed against the remaining notch 2b of the joint body 12.

Next, the operation of each of the above-described embodiments shown in FIGS. 1 to 9 will be described. First, the joint body 2
After inserting the resin tube 6 or 14 to be fused to the joint body 2 or 12 into the connection end of the joint body 2 or 12, the resin tube 6 or 14 is notched using the presser 3 or the spring plate 13 or 17 for the notch to leave the notch 2 b. Or 12b to tighten the resin pipe 6 or 14 to the joint body 2 or 12, so that the resin pipes 6, 14 and the joints 1, 11 and 16 do not move at the time of fusion, and they are uniformly and firmly connected. Can be fusion spliced.

In the embodiment shown in FIGS. 1 to 4, the resin pipe 6 is strongly tightened to the joint body 2 by the action of the cam 5, so that the resin pipe 6 is firmly fixed to the joint 1 and is extremely uniform and strong. A simple fusion splicing can be performed.

In the embodiment shown in FIGS. 5 to 7 and the embodiments shown in FIGS. 8 and 9, the clamping spring plate 1 is used.
The resin pipe 14 can be tightened to the joint body 12 only by pressing the 3 or 17 arc-shaped portions 13a or 17a, and the operation can be performed extremely easily.

In addition, the holding member 3 in the first embodiment
Can be removed after fusion and reused for the next fusion. Further, the clamp spring plates 13 and 17 in the second and third embodiments can be reused similarly.

Since the notches 2d or 12d are formed between the notches 2e and 12e of the joint bodies 2 and 12 at both ends of the notch remaining portions 2b and 12b, the notches 2d and 12d are provided. Notch remaining portions 2b and 12b
Has a slight spring action and acts to promote the tightening effect.

Since the notch remaining portions 2b and 12b of the joint bodies 2 and 12 and the inner peripheral surface of the retainer 3 are provided with notches having a sawtooth cross section, when these are pressed against the surface of the resin pipe 6 or 14, the notches are formed. The movement of the resin tube can be more effectively stopped by biting.

[0030]

According to the electric fusion joint of the present invention, as described above, the inserted resin tube is fixed to the joint main body with the holding member or the spring plate for clamping, and the fusion is reliably and firmly performed. is there. In addition, no special fixing tool or wedge-shaped retaining member is required for fixing, and man-hours for preparing and collecting these are not required. Further, the work is easy even in a narrow work space, and it is not necessary to process the resin pipe with screws or the like, so that the number of work steps can be reduced and it is extremely economical.

[Brief description of the drawings]

FIG. 1 is a perspective partial external view showing an embodiment of an electric fusion joint of the present invention.

FIG. 2 is a partial longitudinal sectional view showing a state where a resin pipe is inserted into the joint main body shown in FIG. 1 and tightened by a fastener.

FIG. 3 is a side view showing a state where a resin pipe is inserted into the joint main body of FIG. 1;

FIG. 4 is a side view showing a state where the presser is mounted and tightened from the state of FIG. 3;

FIG. 5 is a perspective partial external view showing another embodiment of the electric fusion joint of the present invention.

6 is a partial longitudinal sectional view showing a state where a resin pipe is inserted into the joint main body shown in FIG. 5 and tightened by a clamp spring plate.

7 is a side view showing a state in which a resin tube is inserted into the joint main body shown in FIG. 5 and tightened at both leg portions of a clamp spring plate.

FIG. 8 is a perspective partial external view showing still another embodiment of the electrofusion joint of the present invention.

9 is a side view showing a state in which a resin tube is inserted into the joint main body shown in FIG. 8 and tightened by an arc-shaped portion of a clamp spring plate.

FIG. 10 is a perspective external view showing a state in which the joint and the resin pipe are fixed using a welding tool.

[Explanation of symbols]

 1, 11, 16 Electro-fusion joint 2, 12 Joint body 2a, 12a End surface 2b, 12b Notch remaining portion 2c Locking portion 2d, 12d Cut groove 3 Pressing tool (clamping tool) 4 Ring-shaped portion 5 Cam 6, 14 Resin Pipe 12c Guide hole 13, 17 Spring plate for clamping (clamping tool) 13a, 17a Arc-shaped part

Claims (4)

[Claims] At the connection end of the joint body, a predetermined length is cut off from the end face by an appropriate circumference to form a notch remaining portion, and a resin pipe inserted into the connection end of the joint body is inserted into the notch portion. Using a fastener, tighten the remaining notch,
An electric fusion joint wherein the resin pipe is fastened to the joint body. 2. The fastener according to claim 1, wherein the fastener is a substantially semicircular retainer having substantially the same inner diameter as the connection end of the joint body, and the retainer and the remaining notch are connected at both ends thereof. The electric fusion joint according to claim 1, wherein the resin pipe is fastened to the joint body. 3. A coupling ring-shaped portion mounted on one of both ends of the retainer and the remaining portion of the notch is engaged with a locking portion provided on the other end of the holding portion. 3. The electrofusion joint according to claim 2, wherein the holding member is strongly drawn to the remaining portion of the notch by an action of a cam mounted on one or both of the two, and the resin tube is tightened to the joint body. 4. The clamp according to claim 1, wherein the clamp is a substantially U-shaped clamp spring plate, and both ends of the clamp spring plate have their arc-shaped portions facing the above-mentioned notch remaining portion. When the clamp spring plate is pressed toward the outer peripheral surface of the notch with the arc-shaped portion cut out, the clamp spring plate protruding from the guide hole is inserted. The electrofusion joint according to claim 1, wherein the resin tube is pushed toward the remaining portion of the notch by an elastic force of the portion to return to its unique shape, thereby tightening the resin tube to the joint body.