JPS6080811A - Curled optical fiber code and its production - Google Patents

Abstract

PURPOSE:To enable curling by providing heat insulating layers between optical fibers and a sheath consisting of a synthetic resin. CONSTITUTION:Heat insulating layers 3, 6 are provided between optical fibers 2 and a sheath 7 consisting of a synthetic resin of a cord 1 formed by coating the fibers 2 with the sheath 7 and curling the fibers. Insulated electric wires 4 are provided between the layer 6 and the sheath 7. Such curled cord 1 is formed by providing the heat insulating layers 3, 6 between the fibers 2 and the sheath 7, curling the fibers, dipping the curled cord 1 into a liquid tank kept at the temp. higher than the curling temp. of the synthetic resin until the inside of the sheath 7 attains the curling temp. then cooling the cord 1 taken out of the liquid tank by cooling water. Since the layers 3, 6 are formed between the fibers 2 and the sheath 7, heat is not transmitted up to the fibers 2 even if the cord 1 is dipped in the liquid tank kept at the high temp. and the cord is curled without trouble in such operation. Stretchability is thus provided to the cord without flexing of the optical fibers and the cord is used for a robot, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical fiber curl cord formed by processing an optical fiber into a spiral shape, and a method for manufacturing the same.

Optical fibers are preferably used in a straight line because bending increases transmission loss and there is a risk of bending. If this optical fiber is used in a robot, etc. that has a visual sensor, and the robot or a part of the robot is moved, the optical fiber may bend, so it is necessary to attach the optical fiber to the robot so that it does not bend. Since it is difficult to install optical fibers in a straight line, there is a demand for curled optical fibers.

However, optical fibers used in robots, etc. are coated with synthetic resin such as polyvinyl chloride to prevent damage to the optical fibers. The melting point of is about 90
℃, and there was a problem in that ordinary curling methods could not process optical fibers coated with synthetic resin.

This invention solves the above problems, and its purpose is to provide an optical fiber curl cord that can be curled by providing a heat insulating layer between the optical fiber and the sheath made of synthetic resin, and to manufacture the same. The purpose is to provide a method.

The present invention will be described below based on embodiments shown in the accompanying drawings.

As shown in FIG. 1, a cord 1 to be curled has an optical fiber 2 in the center, the optical fiber 2 is covered with a heat insulating material 3, and an insulated wire 4 and a reinforcing wire 5 are placed around the heat insulating material 3. is wound, a heat insulating material 6 is provided thereon, and the outside is covered with a sheath 7 made of synthetic resin such as polyvinyl chloride.

The cord 1 has fixing parts 8a extending in the radial direction at both ends.
, 8b is wound spirally around a cord supporting member 8 having a predetermined diameter, and both ends of the cord 1 are fixed to fixing parts 8a and 8b with clips, strings, etc. Note that the curl diameter of the cord 1 is desirably 50 or more in consideration of the transmission loss of the optical fiber 2, but it may be smaller if the transmission loss is not a problem.

Next, the cord 1 fixed to the cord support material 8 is immersed for several minutes in a liquid bath whose temperature is approximately 150°C. Note that the liquid in the liquid tank may be any liquid that does not alter the quality of the sheath 7 and does not evaporate at the operating temperature. In addition, the liquid temperature in the liquid tank is higher than the curling temperature of the sheath 7, and when the inner wall of the sheath 7 (the wall surface in contact with the heat insulating material 6) reaches the curling temperature, the optical fiber 2 reaches its melting point. It is acceptable as long as the temperature is not high and does not adversely affect the sheath 7, such as discoloration. Furthermore, the immersion time of the cord 1 should be set until the inner wall of the sheath 7 reaches the curling temperature (it may be calculated in advance through experiments or the like based on the liquid temperature of the liquid bath).

When the cord 1 immersed in the liquid tank is taken out from the liquid tank, it is placed in a water tank (the water temperature may be at room temperature) and cooled. Since the cord 1 is forcibly cooled in the water tank, the sheath 7, which has reached a temperature higher than the melting point of the optical fiber 2, is also rapidly cooled, and the temperature of the sheath 7 becomes lower than the melting point of the optical fiber 2, causing the optical fiber 2 to deteriorate. Never. ``Also, since the sheath 7 has reached the processing temperature, the cord 1 maintains its spiral shape.

In the above embodiment, the cord 1 is a composite body using the optical fiber 2 and the insulated wire 4, but the cord 1 may be composed of the optical fiber 2, the insulation wire 3, and the cable wire.

As described above, in this invention, since a cord is formed by providing a heat insulating layer between the optical fiber 2 and a sheath made of synthetic resin, the cord is immersed in a liquid bath at a temperature higher than the curling temperature of the sheath. However, heat is not transferred to the optical fiber,
Since the cord can be curled and the cord immersed in the liquid tank is forcibly cooled, the heat of the high-temperature sheath 7 is not transferred to the optical fiber.

Furthermore, since the cord of the present invention having an optical fiber is curled, it is stretchable and will not bend even if the optical fiber is moved rapidly. .

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an example of a code according to the present invention;
FIG. 2 is a sectional view of FIG. 1, and FIG. 3 is a perspective view showing an example of the cord support material. DESCRIPTION OF SYMBOLS 1... Cord, 2... Optical fiber, 3, 6... Heat insulating material, 4... Insulated wire, 5... Reinforcement wire, 7... Sheath special YI-Applicant Nippon Tsushin Tun Kama Co., Ltd. Agent Kama 1) Bun 2

Claims (4)

[Claims] (1) An optical fiber curl cord in which an optical fiber is coated with a synthetic resin sheath and curled, and a heat insulating layer is provided between the optical fiber and the sheath. (2) The optical fiber cord according to claim 1, wherein an insulated wire is provided between the heat insulating layer and the sheath. (3) The process of curling a cord with a heat insulating layer between the optical fiber and the synthetic resin sheath, and placing the curled cord in a liquid bath at a temperature higher than the curling temperature of the synthetic resin.
A method for manufacturing an optical fiber curl cord, which comprises the steps of immersing the cord until the inside of the sheath reaches a curling temperature, and cooling the cord taken out from a high-temperature liquid bath with cooling water. (4) The method for manufacturing an optical fiber curl cord according to claim 3, wherein the cord is provided with an insulated wire between the sheath and the heat insulating layer.