JPH04213040A - Optical-fiber proof testing apparatus - Google Patents

Abstract

PURPOSE:To make it possible to perform tension application test even for optical fiber having a small diameter without collapse of a film layer by setting the hardness of a contact member of the optical fiber at a specified hardness or less. CONSTITUTION:A member in contact with the element fiber of the coated optical fiber comprises a material whose Shore-D hardness in JIS-K-7215 is 60 or less in this constitution. Therefore, e.g. be respective bell traps 6 of a turn pulley 4 on the sending side and a turn pulley 9 on the winding side are formed on a material whose Shore-D hardness is 60 or less. A material whose Shore-D hardness is 60 or less is stuck to the outer surfaces of a tension pulley 8 and respective turn-pulley main bodies 5 of the pulley 4 and the pulley 9. Since the parts of the pulley in contact with the element fiber of the coated optical fiber comprises the soft material whose hardness is small, excessive side pressure is not applied on a film layers even at the curved part of the element fiber of the coated optical fiber. Therefore, the film layers are not collapsed with the side pressure even for the element wire of the fiber having the thin film layer and the small diameter.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a proof testing device for testing the mechanical strength of optical fibers, particularly thin optical fibers.

0002

2. Description of the Related Art FIG. 1 shows a conventional proof testing apparatus of this type, in which reference numeral 1 designates a delivery drum. An optical fiber strand 2 to be examined is wound around this delivery drum 1, and the optical fiber strand 2 is fed out at a constant speed. The optical fiber strand 2 sent out from the delivery drum 1 is first transferred to the delivery side dancer roll 3.
It is then sent to the delivery turn pulley 4.

The delivery side turn pulley 4 includes a turn pulley main body 5, a belt wrap 6 that runs while contacting a part of the circumferential surface of the turn pulley main body 5, and three drive pulleys 7 that drive the belt wrap 6 to run. It consists of... The optical fiber 2 guided to the delivery-side turn pulley 4 is inserted between the turn pulley main body 5 and the belt wrap 6, and then sent to the tension pulley 8.

The tension pulley 8 is constantly biased in the feeding direction of the optical fiber 2 by a spring or the like, and the optical fiber 2 passes through the tension pulley 8, reverses its running direction, and moves in the winding direction. When running, tension is applied to the optical fiber 2 in its longitudinal direction.

The optical fiber 2 from the tension pulley 8 is
It is sent to the take-up side turn pulley 9, from there it is sent to the take-up drum 11 via the take-up side dancer roll 10, and is wound up. The take-up side turn pulley 9 has the same configuration as the delivery side turn pulley 4 described above. Further, the pulley group such as the tension pulley 8 is made of metal such as aluminum or stainless steel.

According to this proof testing device, a constant tension is applied by the tension pulley 8 to the optical fiber strand 2 running between the delivery side turn pulley 4 and the winding side turn pulley 9, so that the optical fiber If there are scratches, cracks, etc. on the bare optical fiber or the coating layer that make up the strand 2 and the mechanical strength is reduced, that area will break, making it possible to detect the defective area. Proof testing is now underway.

[0007] By the way, in the proof test using this testing device, due to its mechanism, when tension is applied to the optical fiber strand 2, at the same time a considerably large lateral pressure is applied to the portion that contacts the tension pulley 8.

[0008] Current bare wire diameter is 125 μm, strand diameter is 250 μm.
In the optical fiber strand of m, the coating layer has a strength that is almost permissible against this lateral pressure.

However, when the wire diameter is 150 to 200μ
In the case of a thin optical fiber having a diameter of m, the thickness of the coating layer becomes thin, and the coating layer cannot withstand the above-mentioned lateral pressure and is crushed, so that the bare optical fiber becomes partially exposed. and,
If this bare optical fiber portion comes into contact with a pulley or the like of the testing device, it will easily break.

[0010] For this reason, it is not possible to measure the mechanical strength of the optical fiber itself, and the optical fiber often breaks due to crushing of the coating layer, making accurate proof testing difficult. If this process is not carried out, there are disadvantages such as a decrease in yield.

[0011]

[Problems to be Solved by the Invention] Therefore, the problem to be solved by the present invention is to provide a proof testing device that is capable of performing tension application tests on small-diameter optical fibers without crushing the coating layer. It's about getting.

[0012] In order to solve this problem, in the present invention, all the members of the test equipment that come into contact with the optical fibers are JI
A means of constructing the material from a material having a hardness of Shore D of 60 or less according to S-K-7215 was adopted.

The present invention will be explained in detail below.

[0014] Specific means for constructing the member with which the optical fiber of the testing device comes into contact is made of a material having a hardness of Shore D of 60 or less according to JIS-K-7215.
A method of configuring the belt wrap 6 of each of the delivery side turn pulley 4 and the winding side turn pulley 9 from a material with a shore D of 60 or less, and the pulley circumference of the tension pulley 8 and the turn pulley body 5 of each of the delivery side turn pulley 4 and the winding side turn pulley 9. There is a method of attaching a material with Shore D60 or less to the surface.

Hardness Shore D according to JIS-K-7215
Materials with 60 or less include ethylene-α-olefin copolymer, ethylene-vinyl acrylate, ethylene elastomer, ethylene-acrylic acid copolymer, ethylene-vinyl acetate copolymer, urethane rubber, nitrile rubber, acrylonitrile rubber. , butadiene rubber, chloroprene rubber, and copolymers thereof. These materials can be attached using a sheet of 1 to 3 mm thick of these materials using a common rubber adhesive or the like.

[0016] In such a proof test device, each part such as the pulley that the optical fiber comes into contact with is made of a soft material with low hardness, so even in the curved part of the optical fiber, the coating layer Excessive lateral pressure is no longer applied to the Therefore, even for a small-diameter fiber strand having a thin coating layer, the coating layer is not crushed by the lateral pressure, and breakage of the optical fiber strand due to crushing of the coating layer is prevented. Therefore, a proof test that accurately reflects the mechanical strength of the thin optical fiber strand will be performed.

[0017] A detailed explanation will be given below with reference to examples.

(Example 1) As a test device, a 2 mm thick sheet of ethylene-vinyl acetate copolymer having a Shore D hardness of 28 was attached to the surface of the turn pulley body of the tension pulley and the turn pulleys on the delivery side and take-up side. A proof test was conducted on the following four types (A to D) of optical fiber strands using a belt wrap made of urethane rubber having a Shore D hardness of 40. A-Fiber diameter 125μm, wire diameter 150μmB-Fiber diameter 125μm, wire diameter 180μmC-Fiber diameter 1
25 μm, wire diameter 200 μm D-fiber diameter 125 μm
, Wire diameter 250μm

The conditions for the proof test were a proof line speed of 100 m/min, a strain amount of 1.0%, and a sample length of 100 km. The results were expressed in terms of the number of breaks and are shown in Table 1.

[0020]

[Table 1]

(Comparative Example) As a test device, the tension pulley and the turn pulley bodies of the delivery side and take-up side turn pulleys were made of aluminum, and the belt wrap was made of urethane rubber similar to the example. Similarly, proof tests were conducted on four types of optical fibers. The results are also shown in Table 1.

From the results shown in Table 1, it can be seen that the testing apparatus of the present invention allows correct proof testing.

[0023]

Effects of the Invention As explained above, in the optical fiber proof testing device of the present invention, all of the members that the optical fiber comes into contact with have a hardness of Shore D of 6 according to JIS-K-7215.
Since it is made of a material of 0 or less, accurate proof tests can be performed without crushing due to lateral pressure of the coating layer even on small diameter optical fiber strands with a thin coating layer.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing a proof testing device used for optical fiber proof testing.

[Explanation of symbols]

1 Sending drum 2 Optical fiber wire 3 Sending side dancer role 4 Output side turn pulley 5　Turn pulley body 6 Belt wrap 7 Drive pulley 8 Tension pulley 9 Winding side turn pulley 10 Winding side dancer roll 11 Winding drum

Claims (1)

[Claims] [Claim 1] Consisting of a group of pulleys such as a tension pulley and a take-off pulley, an optical fiber is stretched across these pulley groups and is run while applying a constant tension to the optical fiber.
In a proof testing device that tests the mechanical strength of optical fibers, all of the members that the optical fibers come into contact with are J
An optical fiber proof testing device comprising a material having a hardness of Shore D of 60 or less according to IS-K-7215.