JPH07261062A - Pipe for coating optical fiber and its production - Google Patents

Abstract

PURPOSE:To obtain a pipe for coating optical fiber which permits mass production, is formable to have a long one span and has high flexibility and pressure resistant strength by cutting independent parallel grooves into a spiral or toric shape on the circumference of an extrusion molded pipe. CONSTITUTION:This pipe for coating optical fiber is formed by cutting the parallel grooves 9 of the spiral or annular shape on the surface of an extruded synthetic resin pipe 8 of a single layer consisting of a medium-hardness resin or of double layers consisting of an outer hard layer 8a and inner soft layer 8b to impact the flexibility and the pressure resistant strength thereto and this process is for producing such pipe. Since the pipe has the grooves 9, the flexibility is imparted to the pipe so that the pipe withstand bending of the optical fiber. The residual parts X of the surface remaining between the grooves 9 resist the pressing from outside. Particularly the extruded synthetic resin pipe 8 of the double layers is capable of sufficiently maintaining the pressure resistant strength and the flexibility. Since the inside wall surface is circular free from ruggedness, the optical fiber is insertable in the long one span at one time into the coating pipe.

Description

Detailed Description of the Invention

[0001]

[Industrial application] Optical fiber coated pipe and its manufacturing method.

[0002]

2. Description of the Related Art As shown in FIG. 10, a conventional optical fiber coated pipe has a steel wire or the like embedded in the plastic or rubber of the coated pipe 101 in order to increase its pressure resistance. Unevenness 103 occurs on the wall surface. Therefore, when the optical fiber is inserted, the unevenness 103 becomes an obstacle, and it is not possible to insert the optical fiber having a long span, resulting in a short one span. Further mass production is not possible.

[0003]

[PROBLEMS TO BE SOLVED] To obtain a large-sized optical fiber coated pipe which can be mass-produced, can be extended in one span, and has high flexibility and pressure resistance.

[0004]

[Technical Means] A single layer made of medium-hard resin, or
Optical fiber coating with flexibility and pressure resistance by cutting spiral or annular parallel grooves 5, 7, 8 and 10 on the surface of a multi-layer synthetic resin extruded pipe consisting of an outer hard layer 8a and an inner soft layer 8b. Pipe and its manufacturing method.

[0005]

Since the grooves 5, 7, 9 and 10 are cut, flexibility is imparted, the optical fiber can withstand bending, and the surface residue x left between the grooves against external pressure. Oppose. Especially multi-layer synthetic resin extrusion pipe 8
Has sufficient pressure resistance and flexibility.

Further, since the inner wall surface has a circular shape with no uneven surface, the optical fiber can pass a long one span through the coated pipe at a time.

[0007]

Example 1 In Example 1, as shown in FIGS. 1 to 7, a single-layer pipe made of nylon or Duracon resin and medium-hard resin was extrusion-molded.

As shown in FIG. 1, the single-layer pipe 3 extruded from the extruder 1 is cooled in the cooling section 2 and then the parallel annular grooves 5 are cut by 4. The order of cutting the groove 5 is shown in FIGS.

As shown in FIGS. 3 a and 4 a, the blade 4 stands by on the downstream side of the cooling section 2. Then, as shown in FIGS. 3b and 4b, the bite 5 penetrates into the single-layer pipe 3 and rotates 180 ° as shown in FIGS. 3c and 4c, and further 360 ° as shown in FIGS. 3d and d. While single layer pipe 3
And the cutting of one annular groove 5 is completed.
Then, after being separated from the single-layer pipe 3 as shown in FIGS. 3e and 4e, it returns to the positions shown in FIGS. 3a and 4a.

The depth of the groove 5 is 1 / thick of the thickness of the single-layer pipe 3.
Second place is common, but in short, it is sufficient if the flexibility and pressure resistance of the single-layer pipe 3 can be maintained. The inner wall surface of the single-layer pipe has a circular shape without unevenness. x is the surface remainder left between the grooves 5.

Next, the case of cutting the spiral circular groove 7 shown in FIGS. 6 and 7 will be described. Blade 6 is cooling section 2
It stands by on the downstream side, and as shown in FIGS. 6a and 7a, it digs into the single-layer pipe 3 by the depth of the groove 7. Then, in the horizontal position as it is, rotate 180 ° as shown in FIGS. 6b and 7b. Then, since the single-layer pipe 3 advances in the meantime, a spiral 1/2 pitch is formed.

Then, as shown in FIGS. 6c and 7c, the single-layer pipe 3 is advanced and the blade 6 is rotated by 360 ° to cut the one-pitch spiral. Similarly, the spiral groove 7 is cut thereafter. x is the remaining surface remaining between the grooves 7.

(Second Embodiment) The second embodiment is the outer hard layer 8
The multi-layer extruded pipe 8 composed of a and the inner soft layer 8b is cut with the annular parallel grooves 9 and the spiral groove 10.

For example, the multi-layer pipe may be a combination of hard vinyl chloride and soft vinyl chloride, and hard polyethylene and soft polyethylene. How to cut the groove is the same as in the first embodiment. Its depth is all or half of the thickness of the outer hard layer 8a. The second embodiment is different from the first embodiment in
There is an advantage that flexibility and pressure resistance can be sufficiently obtained.

[0015]

EFFECTS OF THE INVENTION (a) Since the grooves 5, 7, 9 and 10 are cut, flexibility is imparted, the optical fiber can withstand bending, and it is left between the grooves when pressed from the outside. The rest of the surface opposes. In particular, the multilayer synthetic resin extruded pipe 8 can sufficiently maintain the pressure resistance and flexibility.

(B) Since the inner wall surface has a circular shape with no uneven surface, a long one-span optical fiber can be passed through the coated pipe.

(C) Mass production is possible by a step of cooling after extrusion and cutting grooves.

[Brief description of drawings]

FIG. 1 is a flow sheet of a pipe manufacturing apparatus of the present invention,

FIG. 2 is a perspective view of the single-layer pipe 3 in which an annular groove 5 is cut,

FIG. 3 a. The front view of the standby process of the blade 4 when cutting the annular groove 5 in the single-layer pipe 3 is shown. b. Similarly, when the blade 4 cuts into the single-layer pipe 3, c. Similarly, the time when the blade 4 is rotated 180 ° is shown. d. Similarly, it shows the time point when it is rotated 360 °. e. Similarly, the time when the blade 4 is removed is shown.

FIG. 4 a, b, c, d, e: FIG. 43 a, b, c,
The state of d and e is shown by a side view.

FIG. 5 is a perspective view when the spiral groove 7 is cut in the single-layer pipe 3,

FIG. 6 a. When cutting the spiral groove 7 in the single-layer pipe 3, the blade 6 cuts the single-layer pipe 3 in a front view. b. Similarly, it shows the time when the 1 / 2-inch single-layer pipe 3 advances. c. Similarly, the time when the 1-pitch single-layer pipe 3 advances is shown.

FIG. 7 a, b, c: side views showing the states of FIG. 6 a, b, c.

FIG. 8 is a perspective view of the multi-layer pipe 8 in which an annular groove 9 is cut,

FIG. 9 is a perspective view when the same spiral groove 10 is cut,

FIG. 10 is a sectional view of a conventional optical fiber coated pipe,

[Explanation of symbols]

1: Extruder, 2: Cooling section, 3: Single layer pipe, 4:
Blade for cutting annular groove 3, 5: annular groove, 6: blade for cutting spiral groove 7, 7: spiral groove, 8: multi-layer pipe,
8a: outer hard layer, 8b: inner soft layer, 9: annular groove of multi-layer pipe, 10: spiral groove of multi-layer pipe, x:
The rest of the surface.

Claims (6)

[Claims] 1. An optical fiber coated pipe in which a flexible tube is formed by cutting independent parallel grooves 5, 7, 9, 10 in a spiral shape or an annular shape around an extruded pipe 3. 2. The optical fiber coated pipe according to claim 1, wherein the extruded pipe 3 is made of a single layer of medium-hard synthetic resin. 3. The optical fiber coated pipe according to claim 1, wherein the extruded pipe comprises an outer hard layer 8a and an inner soft layer 8b, and the depth of the groove is all or half of the thickness of the outer hard layer 8a. 4. After extrusion, spiral or toroidal independent grooves 5, 7, 9, 10 are provided around the cooled extruded pipe.
A method for manufacturing an optical fiber-coated pipe, which is formed by cutting a flexible tube. 5. The manufacturing method according to claim 3, wherein the extruded pipe 3 is made of a single layer of medium-hard synthetic resin. 6. The method according to claim 3, wherein the extruded pipe comprises an outer hard layer 8a and an inner soft layer 8b, and the depth of the groove is all or half of the thickness of the outer hard layer 8a.