JPS614009A - Manufacture of optical fiber bundle curl cord - Google Patents

Abstract

PURPOSE:To increase the restitutive force of an optical fiber bundle curl cord which is formed spirally around a mandrel so that the contraction speed after drawing is high by detaching the optical fiber bundle curl code from the mandrel and then winding it back in the opposite direction. CONSTITUTION:The cord 16 formed by covering an optical fiber bundle 11 of numbers of optical fibers with a plastic sheath 13 is wound around the mandrel 17, and heat-treated and then cooled; and the spiral curl cord 18 is detached from the mandrel 17. One end of the curl cord 18 manufactued as mentioned above is fixed and the other end is fitted to a rotatable jig, which rotates in the opposite direction of the winding direction to wind the cord back in the opposite direction, thus obtaining a curl cord 19. This curl cord 19 is increased greatly in the contracting speed after drawing and returns to its original length in a short time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for manufacturing a stretchable curl cord incorporating an optical fiber bundle.

(Prior art and its problems) Optical fiber bundles, which are made up of a large number of optical fibers, have many applications because they can transmit images. There is a need for a stretchable optical fiber bundle that connects the light-receiving end of the optical fiber.

As a stretchable optical fiber bundle, JP-A-46=628
As seen in Japanese Patent Application No. 5, an optical fiber bundle curl cord is known, which is formed by forming a coat in which an optical fiber bundle is covered with a plastic sheath into a spiral shape.

Conventionally, in order to manufacture such an optical fiber bundle curl coat, a cord made of an optical fiber bundle covered with a plastic sheath is spirally wound around a mandrel, heated, cooled, and removed from the mandrel. It was manufactured by.

However, optical fiber bundle curl cords made by conventional manufacturing methods have the disadvantage that after being stretched, it takes time for the cord to return to its original length even after the force is removed. For example, if you measure the time it takes to restore the original length after stretching it to twice its length, it will take 1 minute - 2 seconds. This makes it impossible to follow the rapid movement of the device.

[Means for solving problems and their effects]

In order to solve the problems of the prior art as described above, the present invention has developed a method in which a cord consisting of an optical fiber bundle made up of a large number of optical fibers covered with a plastic sheath is spirally wound around a mandrel and heat-treated. After that, the optical fiber bundle is cooled and removed from the mandrel to produce an optical fiber bundle curl cord, in which the optical fiber bundle curl cord removed from the mandrel is wound back in the opposite direction.

In this way, the shrinkage speed after stretching becomes much faster. This is thought to be because by winding the sheath in the opposite direction, the sheath is provided with a strong restoring force that tends to return to the molded shape.

〔Example〕

An embodiment of the manufacturing method of the present invention will be described below with reference to the drawings.

First, 10,000 optical fibers with a diameter of 14 μm were assembled into one
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The optical fibers are aligned at 1.5 dragon angles at both ends of the optical fiber bundle 11, placed inside the frame 12, and hardened with epoxy adhesive.The optical fibers other than both ends are is free. This optical fiber bundle 11 is inserted into a thermoplastic W urethane tube (for sheath) with an inner diameter of 3 m++ and a wall thickness of 1.5 mm, and the optical fiber bundle 11 is inserted between the frame 12 and the sheath 13 at both ends. The optical fiber bundle 11 and the sheath 13 are integrated by inserting the object 14 and tightening the outer periphery of the sheath 13 with a hand 15.

The cord 16 thus obtained was spirally wound around a mandrel 17 having an outer diameter of 15 m+i, as shown in FIG. 1, and heat-treated at 120°C. After heat treatment, cool and curl coat 18 with spiral curls on mandrel 1.
Removed from 7.

After the curled cord I8 thus obtained was stretched to double its length, the time required for it to return to its original length was measured, and found that it took more than 1 minute.

Next, the curled cord 18 produced in the same manner was wound back so that the spiral winding direction was reversed to obtain a curled cord 19 as shown in FIG. 2. Rewinding was performed by fixing one end, attaching the other end to a rotatable jig, and rotating the jig in a direction opposite to the spiral winding direction.

The thus obtained curled cord 19 was stretched to double its length and then the time required for it to return to its original length was measured, and it returned to its original length within 1 second.

Note that repeated expansion and contraction may damage and break the optical fibers in contact with the inner surface of the sheath, so it is recommended that the optical fiber bundle be stored in the sheath while being wrapped with tape that has good slipperiness against the sheath.

〔Effect of the invention〕

As explained above, according to the present invention, by winding a spirally formed cord in the opposite direction, it is possible to manufacture an optical fiber bundle curled cord that has extremely excellent restorability after being stretched.

[Brief explanation of the drawing]

Fig. 1 is a front view showing one step in an embodiment of the manufacturing method of the present invention, Fig. 2 is a front view showing an optical fiber bundle curl cord manufactured through the same process, and Fig. 3 is a front view showing the same curl cord manufactured through the same process. 2 is a cross-sectional view showing the end of a cord used for 11-optical fiber bundle, 13-sheath, 16-cord, 17
~ Mandrel, 19 ~ Optical Fiber Tokarko ``.

Claims (1)

[Claims] A cord made of an optical fiber bundle made up of a large number of optical fibers covered with a plastic sheath is spirally wound around a mandrel, heated, cooled, and removed from the mandrel to produce an optical fiber bundle curl cord. A method for producing an optical fiber bundle curl cord, characterized in that the optical fiber bundle curl cord removed from the mandrel is wound back in the opposite direction.