JPH1016086A - Manufacture of electrofusion-type saddle joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a wire from slipping off from a groove at the time of bend forming. SOLUTION: A method for manufacturing an electrofusion-type saddle joint comprises a process wherein a thermoplastic resin made inner component 1 is injected molded on an insert die 3 having a projection 5 and a groove 6 which are arranged in a vortex state, a process wherein a wire is buried by pushing into the groove 6 of the inner component 1 rotating the inner component 1 together with the insert die 3, a process wherein the wire 7 is pressured from above the projection 5, and melted by heating to be fixed to the inner component 1, a process wherein the wire 7 is engaged with a connector pin, a process wherein the inner component with which the wire 7 is corporated is detached from the insert die 3, bent in a specific saddle form, and cooled, and a process wherein the saddle formed inner component 1 is arranged on a bottom face of a thermoplastic resin made outer component, and the outer component is integrally injection molded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an electric fusion type saddle joint which is used for connecting a plastic pipe and has a heating wire embedded in a contact surface of the pipe.

[0002]

2. Description of the Related Art Conventionally, as one of the methods for manufacturing an electro-fused saddle joint used for providing a branch pipe in the middle of a pipe line of a synthetic resin gas pipe or water pipe, an electric current is supplied. There is a method using an inner member having a spiral groove in which the wire is embedded.

[0003] A process for forming a groove in an inner member (sheet) and a process for spirally pushing a wire into a groove in the inner member and fusing and assembling the same are known as a method for manufacturing an electrofusion saddle joint. A process in which the inner member with the wire attached thereto is bent into a predetermined shape, set in a mold, and injection-molded or inserted into a pipe joint or pressed against a saddle joint to be attached. (Tokuhei 7-1074
No. 36).

[0004]

However, in the above manufacturing method, after the inner member (sheet) is injection-molded,
Remove the inner member that is a molded product from the molding die,
In order to embed the wire spirally in the inner member, it is necessary to attach the inner member to the support means (table) with a clamp, a stopper, or the like, and it takes time to change the process from the injection molding process to the wire embedding process. There is. Further, the inner member removed from the molding die may be curved to cause unevenness, so that the wire in the next step cannot be embedded in the spiral groove in some cases.

Further, the wire may be pushed into the groove of the inner member while being heated by the heating means, that is, while melting the contact portion between the inner member and the heating means, or the wire may be pushed into the groove of the inner member by, for example, a heating roller. When the inner member is bent in a saddle shape, there is a problem that the wire jumps out of the groove from a portion where the wire is not sufficiently pressed down, or the wire floats.

Further, when the pressing plate or the pressing roller for pushing the wire into the groove of the inner member makes a rotary vortex motion in which the rotation axis is gradually displaced, the wire comes off from the groove and the wire cannot be pushed well. I will. In particular, when the thickness of the pressing end portion of the iron-shaped pressing plate and the pressing roller having a straight portion at the tip is made equal to or smaller than the thickness of the wire, a problem that the wire comes off from the groove is likely to occur.

The present invention has been made to solve the above problems, and prevents the wire from jumping out or coming off during the winding,
An object of the present invention is to provide a method for manufacturing an electro-fused saddle joint in which windings and wires can be buried reliably and quickly.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a process for injection-molding a thermoplastic resin inner member having spirally arranged projections and grooves on a nesting die, Pressing the wire into the groove of the inner member while rotating the inner member and embedding the wire; pressing and heating and melting the wire from above the protrusion to fix the wire to the inner member; A step of locking the wire, a step of removing the inner member to which the wire is attached from the telescopic mold, bending and forming the saddle into a predetermined saddle shape, and cooling the outer member made of a thermoplastic resin. And a step of integrally injection-molding the outer member provided on the bottom surface of the member.

In the step of pressing and embedding a wire in the groove of the inner member, the step of attaching the insert type to a support means to which the insert type is detachably attached and which is rotatably supported is provided. The supporting means and the nozzle for supplying the wire and the tip for pressing the wire give a relative amount of movement between the spherical pressing pin and press the wire drawn from the nozzle into the groove of the inner member by the pressing pin. It is preferable that the method comprises a burying process.

[0010]

In the manufacturing method of the present invention, the inner member is injection-molded on the nesting die, and the nesting die is used as it is in the next wire embedding step. The wire is accurately pushed into the spiral groove by being pressed from above the wire guided on the spiral groove of the inner member by the pressing pin near the nozzle. Further, pressure is applied from above the projection, and only the tip portion of the projection is heated and melted to form a resin coating over the entire spiral groove, thereby covering the wire, and fixing the wire to the inner member.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on embodiments with reference to the drawings. FIG. 1 is a perspective view showing an opened state of a mold after injection molding showing one embodiment, and FIG. 2 is a front view showing an inner member injection-molded on a nesting mold. An inner member 1 made of a thermoplastic resin, for example, made of a polyethylene resin, a polypropylene resin, a polyvinyl chloride resin, a polybutene resin, or the like is formed by injection molding on an insert mold 3 inserted in a mold 2. Molded. The inner member 1 has a projection 5 and a groove 6 arranged in a spiral shape over the entire surface around the opening hole 4 and is formed in a substantially rectangular shape. In the present embodiment, the grooves 6 are spirally arranged, for example, in two parallel lines. That is, the groove wound in an inward spiral shape is continuously folded at the inner end, and is then arranged in an outward spiral shape in parallel with the arranged groove. That is, the outer ends formed at the two outer positions of the spiral are the ends of the groove 6, and these ends are formed at positions facing each other with the opening 4 interposed therebetween. In addition, a hole 1 a is provided at the outer end of the groove 6 on the surface of the inner member 1 where the groove 6 is formed.

Next, FIG. 3A is a plan view of an apparatus for explaining a step of pressing and embedding a wire in a groove of an inner member and a step of fixing a wire by pressurizing and heating and melting the inner member. FIG. 3B is a view taken in the direction of arrows AA in FIG. 3A, FIG. 4 is an enlarged view of a state in which the wire is pushed by the nozzle and the pressing pin, and FIG. FIG. 3 shows an enlarged sectional view of an inner member. The telescopic mold 3 is mounted on a rotary table 8 as a support means that is driven to rotate by a motor and a reduction mechanism (not shown),
The rotary table 8 is fixed to a slide table 9 that can move in the X direction, and a moving table 13 to which the nozzle 11 and the pressing pin 12 are fixed is movable in the Y direction and the Z direction (vertical direction). Next, by rotating the turntable 8 in the direction of arrow R, the wire 7
Is drawn out, and the wire 7 is led out between the groove 6 of the inner member 1 and the pressing pin 12 via the hollow nozzle 11. According to the rotation of the turntable 8, the pressing pin 12
The pressing pin 12 pushes the wire 7 into the groove 6 while adjusting the positions of the slide table 9 and the moving table 13 so that the pressing force of the wire 7 and the tension of the wire 7 are constant.
In this embodiment, the movable table 13 on which the nozzle 11 and the pressing pin 12 are assembled can be adjusted vertically, but the rotary table 8 may be adjusted vertically. It is possible to cope with a change in the thickness of the pressing pin 12 and the inner member 1. The tip of the pressing pin 12 has a spherical shape, and the radius of the spherical shape is about four times the diameter of the wire 7. Due to this, in the wire burying process,
The pressing pin 12 can accurately press the wire 7 into the groove 6 even when the pressing shaft 12 makes a rotary vortex movement in which the rotary shaft is gradually displaced. At the same time, the opening of the groove is caulked by the pressing force of the pressing pin 12 to prevent the wire from floating.

Next, the nest 3 is moved in the X direction by the slide table 9, and the nest 3 is brought below the heater 14. The heater 14 is provided with a disk-shaped heater 15, and a pressurizer 16 (for example, an air cylinder) is provided above the heater 15. Next, the operation will be described. When the heater 15 is made of polyethylene resin by using a temperature controller or the like,
The temperature is adjusted to 0 to 180 ° C, and 300 to 40
When the heater 15 is pressed against the inner member 1 twice for about 20 to 30 seconds with a pressure of about 0 kg, the upper part of the projection 5 is melted, and the spiral groove 6 and the entire wire 7 embedded in the groove are removed. A thin resin film is formed to cover. Thereby, the wire 7 can be fixed so as not to fall out of the groove 6. Needless to say, heating and melting by high frequency or ultrasonic waves may be used instead of the electric heater 7.

Next, the connector pin is
a, and the end of the wire 7 is entangled with the connector pin to lock the wire 7 to the connector pin (not shown).

Further, the inner member 1, which has been heated to a high temperature by the heater, is removed from the nest 3 and the inner member 1 is bent into a saddle shape as shown in FIG. The inner member 1 is inserted between the mold 17 and the female mold 18, and the male mold 17 is pressed from above to be cooled and solidified.

Next, as shown in FIG. 7, the inner member 1 bent into the saddle shape is disposed as an insert on a mold 19a so as to be on the bottom surface of the outer member.
By injecting the molten thermoplastic resin into the cavity 20 surrounded by 9a, 19b, 19c, 19d, and 19e, the outer member is integrally formed, and finally, an electro-fused saddle joint can be manufactured. Although the embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment. included.

[0017]

As described above, in the method of manufacturing the electro-fusible saddle joint according to the present invention, the inner member injection molding step, the wire embedding step, the pressurization of the inner member, and the heat melting are performed. The time required for the setup change can be reduced by using the nested type consistently in the wire fixing step and the wire connector pin connecting step. In addition, since the inner member is not removed from the injection molding die, the inner member is not bent and deformed, and the wire can be embedded in the flat groove of the inner member. Further, by using a pressing pin having a spherical tip and a spherical radius about four times the wire diameter, the wire can be accurately pushed into the groove without coming off the groove.
When a disk-shaped heater is pressed and heated and melted so as to cover the spiral groove and the entire wire embedded in the groove, a thin resin film is formed, and when the inner member is bent into a saddle shape, The wire will not fall out of the groove.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an opened state of a mold after injection molding according to an embodiment of the present invention.

FIG. 2 is a front view showing an inner member injection-molded on a nesting die according to the embodiment of the present invention.

FIG. 3 (a) is a plan view of an apparatus for explaining a step of embedding a wire by pressing it into a groove of an inner member and a step of fixing a wire by pressurizing and heating and melting the inner member, showing an embodiment of the present invention. FIG. (B) is AA of (a).
It is an arrow view.

FIG. 4 is an enlarged view showing a state in which a wire is pushed by a nozzle and a pushing pin according to the embodiment of the present invention.

FIG. 5 is an enlarged cross-sectional view of a wire and an inner member buried by pressing according to the embodiment of the present invention.

FIG. 6 is a front view of a bending machine for explaining a bending process of forming an inner member into a saddle shape according to the embodiment of the present invention.

FIG. 7 is a sectional view showing a mold for injection-molding a saddle joint provided with an inner member.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Inner member, 1a ... Hole 2 ... Mold, 3 ... Nesting mold 4 ... Opening hole, 5 ... Projection 6 ... Groove, 7 ... Wire 8 ... Rotary table, 9 ... Slide table 10 ... Bobbin, 11 ... Nozzle 12 ... Pressing pin, 13 ... Moving stage 14 ... Heating device, 15 ... Heater 16 ... Pressurizing device, 17 ... Male type 18 ... Female type, 19a, 19b, 19c, 19d, 19e
... Mold, 20 ... Cavity

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location // B29L 23:00 31:24 (72) Inventor Kiyoshi Ikeda 2 Daifuku, Kuwana-shi, Mie 2 Hitachi Metals Kuwana Plant Co., Ltd. (72) Inventor Toshihiro Kawazoe 498-1 Masuda, Kuwana-shi, Mie Fuso Koki Co., Ltd.

Claims (2)

[Claims] 1. A process of injection-molding a thermoplastic resin inner member having a spirally arranged protrusion and groove on a nesting die, and rotating the inner member together with the nesting die while rotating the inner member. A step of pressing and embedding a wire in the groove of the inner member, a step of pressing and heating and melting the wire from above the projection to fix the wire to the inner member, and a step of locking the wire to a connector pin; Removing the inner member to which the wire is attached from the telescopic mold, bending the inner member into a predetermined saddle shape, and cooling; and disposing the saddle-shaped inner member on the bottom surface of an outer member made of a thermoplastic resin. A method of integrally injection-molding a member. 2. A step of pressing the wire into the groove of the inner member and embedding the wire into the groove, the step of attaching the insert mold to a support means to which the insert mold is detachably attached and which is rotatably supported. The tip which presses and presses the wire and the nozzle for supplying the wire with the support means gives a relative movement amount between the pressing pin and the wire, and the wire pulled out from the nozzle is pressed against the groove of the inner member by the pressing pin. 2. The method for manufacturing an electro-fusible saddle joint according to claim 1, comprising a step of burying the joint.