JPH07117636B2 - Optical communication cable spacer manufacturing equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an optical communication cable manufacturing apparatus, and more particularly to a manufacturing apparatus for a spacer having an optical core housing groove on the outer periphery for housing an optical fiber core wire.

[Prior Art] Generally, as a structure of an optical communication cable, a spacer type, a twisted type, a unit type and the like are known. Among them, the spacer type optical fiber cable has a structure in which a fiber core wire (optical core) is housed in a groove provided on the outer periphery of the spacer to protect it from external force, and is suitable for an optical fiber cable having 12 or less fibers.

Usually, in this spacer type optical fiber cable, in order to allow the optical fiber to withstand the tension when the cable is laid, as shown in FIG. It is located in the center. Further, the optical core accommodating groove 22 on the outer periphery of the spacer is formed in a spiral shape, and the optical fiber core wire in the cable is twisted so that excessive tension is not applied to the optical fiber when the cable is bent.

An outline of a conventional spacer manufacturing method will be described with reference to FIG.

First, the tension member 2 is fed from the feeding drum 1. In the extruder 3, a resin such as polyethylene (PE) or polyvinyl chloride (PVC) is pushed out to the cross head 4, and the spin holder 6 and the spinneret 12 are rotated by the rotation driving device 6 via the sprocket 5. The resin is extruded through the inside of the rotating base 12 and the tension member 2
The resin is coated on the spacers to form spacers 21 (FIG. 3). At this time, a plurality of protrusions 12a are provided on the inner circumference of the tip of the base 12 in the circumferential direction, so that the outer surface of the spacer 21 has a third
The optical core housing groove 22 as shown in the figure is formed in a spiral shape.
The extruded spacer 21 is cooled and solidified in the cooling water tank 7, taken up by the take-up machine 8, and taken up by the take-up drum 9.

The extrusion in the extrusion head portion is performed as follows.

In FIG. 1, first, the resin is extruded by the extruding screw 10 of the extruder 3 and flows to the crosshead 4, passes through the resin flow path 14, crosses to form an annular body, and reaches the die 12. The tension member 2 pulled to the left in FIG. 1 by the take-up machine 8 enters from the mandrel holder 13, passes through the mandrel 20 at its tip, passes through the base 12, and exits from the extrusion head. The tension member 2 is coated with resin at the tip of the base 12. In this case, the rotary cap holder 11 rotatably supported on the flange 17 by the bearing 19
Is connected to the motor of the rotation drive device 6 via the sprocket 5, and by rotating the motor, the rotary cap holder 11 and the cap 12 rotate integrally. Therefore, the spacer 21 extruded from the die 12 is extruded in the form of a spacer containing a tension member having a helical optical core accommodating groove 22. 15 and 16 are core holder 13 and flange 1.
7 is a fixing bolt, and 18 is a rotating packing.

[Problems to be Solved by the Invention] However, the resin extruded by the extrusion screw 10 flows into the resin passage 14 and crosses to form a laminar flow.
And flows straight through the resin passage 14 to the base 12. For this reason, the pressure in the head, that is, the so-called annular resin pressure is not uniform, and the extruded spacer cross section collapses the optical core storage groove or the spacer cross section collapses, that is, the wall thickness, the projection width, the projection height, etc. Irregularity, uneven thickness, etc. will occur.

In addition, since the spacer cross section may be eccentric, the extrusion speed, that is, the take-up speed must be slowed, which causes a problem that productivity is deteriorated.

The present invention has been made in view of the above-mentioned problems, and it is possible to obtain a spacer cross section having a uniform laminar annular resin pressure, no groove collapse, irregular shape dimensions, eccentricity, and the like. It is an object of the present invention to provide a spacer manufacturing method for an optical communication cable.

[Means for Solving the Problems] In the spacer manufacturing apparatus for an optical communication cable according to the present invention for solving the above problems, a resin passage is formed around a mandrel for feeding a tension member, and a tip portion of the mandrel is provided. In a spacer manufacturing apparatus for an optical communication cable, in which a resin extruded in the resin passage is sequentially coated on a tension member extended from the above, a ring-shaped dam is provided on an outer peripheral portion of the mandrel to form an inner wall of the resin passage. A ring-shaped narrowed portion is formed between the core and the ring-shaped dam portion, and on both sides of the ring-shaped dam portion, a metal core expansion portion is formed which extends substantially toward the center from the outer edge portion of the dam portion, and the resin extrusion is performed. The inclination of the mandrel expanded portion on the upstream side in the direction is formed to be gentler than the inclination of the mandrel expanded portion on the downstream side in the extrusion direction.

[Function] The resin that has become a laminar flow in the form of an annular body through the resin passage is transferred to the outside in the radial direction by the dam bank portion of the mandrel, and is squeezed when passing through the throttle portion to increase the pressure. Will be dispersed in the circumferential direction and made uniform. Therefore, since the resin is uniformly coated on the tension member, the extruded spacer is free from groove collapse, irregular shape dimension, eccentricity and the like as viewed from the spacer cross section. In addition, on both sides of the dam portion, a cored bar expanded portion is formed which extends substantially toward the center from the outer edge part of the dam part, and the inclination of the cored bar expanded portion on the upstream side in the resin extrusion direction is set to the downstream side in the extrusion direction. Since it is formed more gently than the inclination of the core metal expansion part, when the resin extruded in the resin passage with uneven pressure reaches the throttle part, it is gradually pressurized and the pressure difference before and after the dam is large. Then, the extruded resin smoothly passes through the narrowed portion. Therefore,
The coating speed can be greatly increased as compared with the case where the narrowed portion is simply formed.

[Examples] Hereinafter, the present invention will be described with reference to illustrated examples.

The extrusion method and procedure are almost the same as the conventional one, and the difference is that the mandrel 30 shown in FIG. 2 is used instead of the conventional mandrel 20 shown in FIG.

In FIG. 2, the mandrel 30 has a dam part (dam part) 31 that bulges in a ring shape from the center thereof in the radial direction, and the radius thereof is equal to that of the cap holder 11 or the resin passage 14 of the cap 12. The diameter is made slightly smaller than the inner wall diameter, and a narrow passage through which the resin passes, that is, the narrowed portion 40 is formed between the dam portion 31 and the resin passage inner wall. The cross-sectional shape of the dam portion 31 of the mandrel 30 is formed as the mandrel expanded parts 32 and 33 which are gradually thickened from the middle thereof toward the base part, and particularly, of the mandrel expanded part 32 on the upstream side in the extrusion direction. The inclination is formed to be gentler than the inclination of the downstream core metal expansion portion 33. In the extrusion head, a transfer layer 41 is formed on the front wall side, which transfers the resin laminarly flowing into the resin passage 14 in a laminar manner to the outer circumferential wall in a ring shape.
This is because the pressure release portion 42 for releasing the pressure of the resin throttled by the throttle portion 40 is formed on the rear wall side. In the case of this embodiment, the diameter of the cored bar 30 is different on both sides of the dam portion 31, and the diameter on the upstream side in the extrusion direction is larger than the diameter on the downstream side, but it is not always necessary to make them different. Absent.

Since the mandrel 30 is configured as described above, first, the resin extruded by the extrusion screw 10 is formed in the mandrel expanded portion 32 when it becomes a ring-shaped body through the resin passage 14 and flows laminarly. The resin is guided by the layer transfer portion 41 in the resin passage 14 and transferred to the radially inner circumferential inner wall. Then, near the inner wall of the rotating mouthpiece holder 11 or the mouthpiece 12, it passes through the narrowed portion 40. That is, the transferred resin is squeezed by the narrow passage of the squeeze 40 to increase the pressure, and becomes a uniform pressure in the circumferential direction, that is, in an annular shape. After that, the annular resin having a uniform pressure flows into the pressure releasing portion 42, reaches the die body, and is extruded.

In this way, by providing the dam portion 31 and making the annular resin pressure uniform in the circumferential direction, the tension member 2 is evenly covered, so that as shown in FIG. As seen from the cross section of the spacer, the groove collapse, the disorder of the shape dimension, the eccentricity, etc. are eliminated, and the spacer cross section with extremely high accuracy can be obtained. Further, since the pressure difference before and after the dam portion becomes large and the extruded resin passes through the throttle portion smoothly, it is possible to greatly increase the coating speed as compared with the case where the throttle portion is simply formed.

[Advantages of the Invention] The present invention, which is configured as described above, has the following advantages.

(1) It is possible to obtain a very good spacer cross section that is free from groove collapse in the longitudinal direction of the spacer and is free from eccentricity.
The performance of optical communication cables is also improved.

(2) Since the resin flow is smooth even if the dam portion is provided, the take-up speed can be increased several times as compared with the conventional one, and the productivity can be remarkably improved.

[Brief description of drawings]

FIG. 1 is a sectional view of a head assembly for pushing out a spacer, and FIG.
FIG. 3 is a cross-sectional view of a mandrel with a dam portion and a resin passage portion used in the present invention, FIG. 3 is a cross-sectional view of an extruded spacer, and FIG. 4 is a block diagram showing a conventional spacer manufacturing line device. In the figure, 1 is a feeding drum, 2 is a tension member, 3
Is an extruder, 4 is a crosshead, 5 is a sprocket, 6 is a rotation driving device, 7 is a cooling water tank, 8 is a take-up machine, 9 is a take-up drum, 10 is an extrusion screw, 11 is a die holder, 12 is a die, 13 Is a core holder, 14 is a resin passage portion, 19 is a bearing, 20 is a core, 21 is a spacer, 22 is an optical core storage groove, 30 is a core, 31 is a dam, 32 and 33 are core extensions, 40 is a diaphragm part, 4
Reference numeral 1 indicates a layer transfer section, and 42 indicates a pressure release section.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akira Shoji 5-1-1 Hidaka-cho, Hitachi-shi, Ibaraki Hitachi Cable Co., Ltd. Hidaka factory (72) Inventor Riki Endo 5 Hidaka-cho, Hitachi-shi, Ibaraki 1-1-1 Hitachi Cable Co., Ltd. Hidaka Plant (72) Inventor Aketsu Takahashi 5-1-1 Hidakacho, Hitachi City, Ibaraki Hitachi Cable Co., Ltd. Hidaka Plant (56) References 58-134607 (JP, A) JP-A-59-208508 (JP, A) Handbook of Plastic Processing Technology (new edition) "(44-12-5) Nikkan Kogyo Shimbun P. 265-266, P. 293-294

Claims (1)

[Claims] 1. A light for forming a resin passage around a mandrel for feeding a tension member, and coating a resin extruded in the resin passage on a tension member extended from the tip of the mandrel. In a spacer manufacturing apparatus for a communication cable, a ring-shaped dam portion is provided on the outer peripheral portion of the mandrel to form an annular narrowed portion between the inner wall of the resin passage and both sides of the ring-shaped dam portion, Forming a mandrel expanded portion that extends substantially toward the center from the outer edge of the dam portion,
An apparatus for manufacturing a spacer of an optical communication cable, characterized in that the inclination of the mandrel expansion portion on the upstream side in the resin extrusion direction is formed to be gentler than the inclination of the mandrel expansion portion on the downstream side in the extrusion direction.