JP2017067187A - Apparatus and method for manufacturing heating wire of electrofusion joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus and a method for manufacturing a heating wire of an electrofusion joint, which enable a coil, formed by winding the resin-coated heating wire around a spindle, to be smoothly ejected from the spindle.SOLUTION: A heating wire W is wound around an outer peripheral surface of a spindle 1. The heating wire W is welded by an iron 4 and shape-retained. Subsequently, a coil C is stripped from the spindle 1 by being pushed by a sleeve 2. A large number of recessed holes 1a are provided on the outer peripheral surface of the spindle 1. A dimension d of the recessed hole 1a is smaller in dimension than the thickness t of the iron 4.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an apparatus and a method for producing a heating wire coil of an electrofusion joint (electric fusion joint).

  An electrofusion joint used as a pipe joint of plastic pipes (synthetic resin pipes) such as water and sewage pipes and gas pipes is a molded product in which a coil of a covered heating wire that generates heat when energized is embedded on the inner peripheral side. After the plastic tube is inserted into the joint, the electrofusion joint and the plastic tube are connected by energizing and heating and melting the connection surface.

  As a method for manufacturing a heating wire coil for such an electrofusion joint, after winding a resin-coated heating wire around the spindle without gaps, the resin-coated heating wires are fused together to form a coil. A method of extracting from the spindle is performed (for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 1-164889

  The surface of the spindle around which the resin-coated heating wire is wound is often plated with hard chrome or the like to prevent rust. Further, in order to make the inner peripheral surface of the wound coil a smooth surface, it has been common to make the outer peripheral surface of the spindle a smooth surface.

  In a winding process in which a resin-coated heating wire is wound around a spindle to form a coil, the coil is wound with a constant tension applied so as not to be loosened. In the step of ejecting the coil wound around the spindle from the spindle, the coil is pushed and ejected in the axial direction of the spindle. However, since the coil is attached to the spindle and is in close contact with it, a large pushing and ejecting force is required.

  In particular, in a spindle having a plating process or a smooth outer peripheral surface, the adhesion force between the spindle outer peripheral surface and the resin-coated heating wire coil is large, and a large discharging force is required for discharging.

  When the side surface of the coil of the resin-coated heating wire is pressed with a large pushing / discharging force at the time of discharging, the coil end surface (pressing surface) may be crushed and deformed, and the shape of the coil may be disturbed.

  Moreover, by being crushed and deformed, the resin-coated heating wire itself is also deformed, and the interval between adjacent heating wires may be disturbed. When the interval between the heating wires becomes narrow, there is a possibility that the heating wires are short-circuited at the time of electrical fusion bonding of the joint.

  An object of the present invention is to provide an electrofusion joint heating wire coil manufacturing apparatus and manufacturing method in which a coil formed by winding a resin-coated heating wire around a spindle can be smoothly discharged by the spindle.

  A heating wire coil manufacturing apparatus for an electrofusion joint according to the present invention includes a spindle around which a resin-coated heating wire is wound, and a demolding means for demolding the coil wound around the spindle by pushing it in the spindle axis direction. And a heating wire coil manufacturing apparatus having a trowel pressed against the wound resin-coated heating wire, the outer peripheral surface of the spindle is provided with a concave hole and / or a concave strip for reducing frictional resistance when the coil is removed. The concave hole has a diameter smaller than the thickness of the iron, and the groove width of the groove is smaller than the thickness of the iron.

  The method for manufacturing an electrofusion joint heating wire coil of the present invention manufactures a heating wire coil of an electrofusion joint using such a manufacturing apparatus.

  In the heating wire coil manufacturing apparatus and manufacturing method for an electrofusion joint according to the present invention, friction between the coil wound around the spindle and the outer peripheral surface of the spindle is small, and the coil can be smoothly discharged from the spindle.

  In the present invention, when the iron for integrating the wound resin-coated heating wire is pressed against the coil, the resin is not pushed into the concave portion of the spindle outer peripheral surface, and the coil is smoothly discharged from the spindle. Can do.

  Therefore, according to the present invention, when the coil is discharged from the spindle, it is sufficient that the discharging force applied to the coil is small, the deformation of the coil is prevented, and the interval between the heating wires can be made as specified.

It is a perspective view explaining the present invention. It is a perspective view explaining the present invention. It is a perspective view explaining the present invention. It is a perspective view explaining the present invention. It is a perspective view of a spindle, and a sectional view of a part of the outer peripheral surface. It is a perspective view of a spindle, and a sectional view of a part of the outer peripheral surface. It is sectional drawing of a part of outer peripheral surface of a spindle which shows a comparative example. It is sectional drawing which shows an example of an electrofusion coupling.

  Hereinafter, embodiments will be described with reference to the drawings. FIGS. 1-6 has shown the apparatus and method which manufacture the heating wire coil of an electrofusion joint using a resin coating heating wire.

  This heating wire coil manufacturing apparatus includes a spindle 1, a rotary drive device (not shown) such as a servo motor for rotating the spindle 1, and an axial direction for moving the spindle 1 back and forth in the axial direction. An actuator (not shown), a cylindrical discharge sleeve 2 (mold removing means) in which the spindle 1 is inserted, a heating wire sending mechanism 3 that sends out a resin-coated heating wire W in the tangential direction of the outer peripheral surface of the spindle 1, A clamp (not shown) for pressing and pressing the winding start end of the heating wire W against the outer periphery of the spindle 1 and the outer periphery of the coil C wound around the spindle 1 can move back and forth in the direction perpendicular to the axis of the spindle 1. It has a trowel 4 that can contact and separate from the surface, and a cutter (not shown) for cutting the heating wire W between the heating wire W sent from the delivery mechanism 3 and the heating wire winding body. The iron 4 is a heating iron having a heater. The clamp can rotate coaxially with the spindle 1 integrally with the spindle 1.

  The heating wire coil manufacturing apparatus further includes a folding mechanism (not shown) that folds both ends of the heating wire W wound in a coil shape in a direction perpendicular to the axis of the spindle 1 and covers both ends of the heating wire W. It has a slit top mechanism 5 for cutting out the resin to expose the core wire W ′, and a crimping mechanism (not shown) for fixing the terminal 6 to the exposed core wire W ′ at both ends of the heating wire W by caulking. The outer peripheral surface of the spindle 1 is roughened as described later.

  In addition, examples of the resin of the resin-coated heating wire W include polyolefins such as polyethylene and polypropylene, and examples of the core wire include iron chrome wire, copper nickel wire, and nickel wire, but are not limited thereto. Moreover, although the shape of the resin of the resin-coated heating wire W is shown in FIGS.

  In order to manufacture the coil C using this heating wire coil manufacturing apparatus, the heating wire W is sent out in a direction perpendicular to the axis of the spindle 1 from the feeding mechanism 3, and its starting end is along the outer peripheral surface of the spindle 1 to clamp it. After the spindle 1 is fixed to the outer peripheral surface of the spindle 1 by rotating the spindle 1 around its axis, the spindle 1 and the sleeve 2 are gradually retracted to the axis, and the heating wire W is applied to the outer surface of the spindle 1. Wrap.

  While the spindle 1 makes one revolution, the spindle 1 moves backward by the width of the heating wire W. Thereby, the heating wire W is wound around the outer peripheral surface of the spindle 1 without a gap (FIGS. 1B to 1C).

  After the heating wire W is wound around the spindle 1 for a predetermined turn, the spindle 1 is stopped and the delivery of the heating wire W from the delivery mechanism 3 is stopped. Next, as shown in FIG. 1 (d), the heated iron 4 is pressed against the outer peripheral surface of the wound body of the heating wire W. Thereby, as shown in FIG. 2A, the iron pressing portion of the wound heating wire W is fused, and the heating wire W is shaped like a coil. Reference numeral 4 a in FIG. 2A indicates a fusion part formed by pressing the iron 4. The fused portion 4 a extends in a direction parallel to the axis of the spindle 1.

  Next, as shown in FIG. 2 (a), after the heating wire W is cut between the delivery mechanism 3 and the wound body, the spindle 1 is rotated around its axis as shown in FIG. The iron 4 is pressed while being rotated by 45 ° in the example to form a plurality of (four in the illustrated example) fused portions 4a.

  Next, as shown in FIG. 3 (a), both ends of the heating wire W are folded in a direction perpendicular to the axis of the spindle 1, and the coating resin is cut off from the tip of the heating wire W by the strip mechanism 5 and the core wire W '. Is exposed (FIGS. 3B to 3C).

  Next, as shown in FIG. 4A, the root portion of the terminal 6 is externally fitted to the tip end of the core wire W ′, the root portion of the terminal 6 is crimped by a caulking mechanism, and the terminal 6 is crimped to the core wire W ′. Thereafter, the spindle 1 is retracted into the sleeve 2 and the coil C is pushed by the front end surface of the sleeve 2 to release the coil C from the spindle 1 (FIGS. 4B to 4C).

  In order to smoothly remove the coil C, the outer peripheral surface of the spindle 1 is roughened. An example of this roughening process is shown in FIGS.

  In FIG. 5, a large number of concave holes 1 a are provided on the outer peripheral surface of the spindle 1. As shown in FIG. 5B, the diameter d of the recessed hole 1 a is smaller than the thickness t of the iron 4. For this reason, when the iron 4 is pressed against the outer peripheral surface of the heating wire wound body, the resin of the resin-coated heating wire W is not pushed into the concave hole 1a, and the coil C can be smoothly removed from the spindle 1. Can do.

When the diameter of the spindle 1 is 15 to 30 mm, the diameter d of the recessed hole 1a is preferably about 0.05 to 0.5 mm, particularly preferably about 0.3 to 0.5 mm, and the depth is preferably about 0.3 mm. It is about 025 to 0.25 mm, particularly preferably about 0.15 to 0.25 mm. The arrangement density of the recessed holes 1a is preferably about 150 to 15,000, particularly about 150 to 500 per 1 cm ² of the outer peripheral surface of the spindle 1. Moreover, it is preferable to make the diameter d of the recessed hole 1a smaller than the external dimension of the resin of the resin-coated heating wire W. In particular, about 1/3 of the outer dimension is preferable because the resin-coated heating wire W does not enter the concave hole 1a.

  In FIG. 6, a large number of ridges (grooves) 1 b extending in the direction parallel to the axis of the spindle 1 are provided on the outer peripheral surface of the spindle 1. The groove width e of the recess 1b is also smaller than the thickness t of the iron 4, so that the resin is not pushed into the recess 1b when the iron 4 is pressed against the heating wire wound body. . By providing the recess 1b, the coil C can be smoothly removed from the spindle 1. In particular, in FIG. 6, since the concave strip 1b is parallel to the axis of the spindle 1, the friction between the coil C and the outer peripheral surface of the spindle 1 at the time of demolding is sufficiently small.

  When the diameter of the spindle 1 is 15 to 30 mm, the width e of the groove 1b is preferably 0.05 to 0.5 mm, particularly preferably about 0.3 to 0.5 mm, and the depth is preferably 0.025 to 25 mm. It is about 0.25 mm, especially about 0.15 to 0.25 mm. The interval between the concave strips 1b is preferably about 0.15 to 1.5 mm, particularly about 0.6 to 1.5 mm.

  7 shows a comparative example in which the width e of the recess 1b is smaller than the thickness t of the iron 4. In this case, when the iron 4 is pressed against the heating wire wound body, the resin is pushed into the recess 1b, and there is a possibility that the friction between the coil C and the outer peripheral surface of the spindle 1 increases.

  FIG. 8 shows an example of an electrofusion joint including a coil C manufactured by the method and apparatus of the present invention. The electrofusion joint 10 has insertion holes 11 into which both ends of the plastic pipe are inserted. However, the electrofusion joint may be a multi-way joint having three or more insertion holes 11 or a cap having only one insertion hole so as to seal the tip of the pipe.

  The above description is an example of the present invention, and the present invention may be other than the above. For example, the roughening of the outer peripheral surface of the spindle 1 may be formed by blasting. Moreover, even if it is a case where the concave hole 1a and the concave strip 1b are provided, you may use a blast process together. In the above description, the coil C is removed by moving the spindle 1 backward, but the coil C may be removed by moving the sleeve 2 forward.

  When the heating wire W is wound around the spindle, the heating wire feeding mechanism may be moved in parallel with the spindle, and the spindle may not be moved but only rotated.

Hereinafter, comparative examples and examples will be described.
[Comparative Example 1]
A heating wire W having a core wire diameter of 0.3 mm and an outer dimension of 1.35 mm was wound around the outer peripheral surface of a 17 mm diameter spindle whose outer peripheral surface was hard chrome plated for 22 turns. In addition, the cross-sectional shape of the heating wire W is a square, and 1.35 mm is the length of one side of the square. The coating resin is polyethylene. A trowel having a thickness of t = 1.0 mm was pressed to keep the coil C in shape.

The torque of the sleeve forward drive motor when the wound body of the heating wire W was pushed by the sleeve and removed was measured, and the torque at this time was set to 100%.
[Example 1]
In Comparative Example 1, the same test as in Comparative Example 1 was performed except that 61 V-shaped concave strips 1b having a groove width e = 0.3 mm and a depth of 0.15 mm were formed on the outer peripheral surface of the sleeve 1. . The torque at the time of demolding was 65% of Comparative Example 1.
[Example 2]
In Comparative Example 1, the same test as in Comparative Example 1 was performed except that the outer peripheral surface of the sleeve 1 was subjected to a blast treatment with a surface roughness of 0.6 mm. The torque at the time of mold removal was 52% of that of Comparative Example 1.
[Example 3]
In Example 1, the same test as in Comparative Example 1 was performed except that the outer peripheral surface of the spindle 1 was further subjected to the same blasting treatment as in Example 2. The torque at the time of demolding was 32% of Comparative Example 1.

  From the above Examples and Comparative Examples, it was confirmed that the coil can be smoothly demolded according to the present invention. In addition, when the shape of the coil after demolding was observed, all of Examples 1 to 3 were good, but in Comparative Example 1, it was recognized that the side surface was deformed.

1 Spindle 2 Sleeve 3 Heating wire feed mechanism 4 Iron 5 Strip mechanism 6 Terminal

Claims (4)

A spindle around which the resin-coated heating wire is wound, a demolding means for pushing the coil wound around the spindle in the direction of the spindle axial line, and a mold pressed against the wound resin-coated heating wire. In a heating wire coil manufacturing apparatus of an electrofusion joint having
On the outer peripheral surface of the spindle, a concave portion made of a concave hole and / or a concave strip is provided for reducing frictional resistance when removing the coil.
An apparatus for producing a heating wire coil of an electrofusion joint, wherein the diameter of the concave hole is smaller than the thickness of the iron, and the groove width of the concave stripe is smaller than the thickness of the iron.   The heating wire coil manufacturing apparatus for an electrofusion joint according to claim 1, wherein the concave stripe extends in the axial direction of the spindle.   The heating wire coil manufacturing apparatus for an electrofusion joint according to claim 1 or 2, wherein the outer peripheral surface of the spindle is a blast surface.   The manufacturing method of the heating wire coil of the electrofusion joint which manufactures a heating wire coil using the heating wire coil manufacturing apparatus of the electrofusion joint of any one of Claim 1 thru | or 3.

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