JP5644816B2 - Method and apparatus for manufacturing slot rod for optical cable - Google Patents

Description

  The present invention relates to a method and an apparatus for manufacturing a slot rod for an optical cable that houses a plurality of optical fibers.

  In a data communication service for home using optical fiber (FTTH: Fiber To The Home), an optical fiber is drawn from a trunk optical cable to a subscriber's house or the like using a drop optical cable. For example, an optical fiber is pulled down to a subscriber's house, for example, a trunk optical cable laid on a utility pole in a city is branched by a connection box usually called a closure, and a drop optical cable is connected to the branched optical fiber. Connected.

  As the trunk optical cable, for example, a slot-shaped optical cable 1 as shown in FIG. 5 is frequently used. The optical cable 1 is composed of a resin slot (also referred to as a spacer) 2 in which a strength member (also referred to as a tension member) 3 is embedded in the center. The tensile body 3 is formed by coating a resin coating layer 3b for bonding and integrating with a resin slot 2 around a tensile wire 3a such as a steel wire. Usually, low-density polyethylene is used for the resin coating layer 3b, and high-density polyethylene is used for the slot 2.

The slot 2 is provided with a plurality of grooves 2a. The grooves 2a are arranged at substantially equal intervals along the circumferential direction of the slot 2, and the adjacent grooves 2a are divided by the slot rib 2b. Normally, a plurality of multi-fiber optical fiber ribbons 4 are accommodated in the groove 2a, but a plurality of single-fiber optical fibers may be accommodated.
A presser winding tape 5 is wound around the outside of the slot 2 in which the optical fiber ribbon 4 is accommodated, and a protective sheath (also called a jacket) 6 is covered on the outside. The sheath 6 is formed by extruding, for example, a polyethylene resin or a flame-retardant polyethylene resin on the press-wound tape 5.

  The slot 2 is roughly classified into two types according to the shape of the groove 2a. One is a type having a unidirectionally twisted spiral groove called HL, and the other is a type having a bidirectionally twisted groove inverted to the left and right in the longitudinal direction, called SZ. In recent years, SZ-type slots that are easy to perform a branching operation (also referred to as an intermediate post-branch) for drawing an optical fiber from a middle portion of the optical cable 1 have become mainstream.

  Here, in order to maintain the transmission characteristics of the optical cable 1, the groove 2a of the slot 2 has a groove reversal angle and pitch defined. For example, Patent Document 1 discloses a technique for manufacturing a slot with a groove, and the manufacturing apparatus is located on a gripping part that grips a tensile body having a resin coating layer, or on the downstream side of the gripping part, An extrusion molding machine for coating the tensile strength body with the resin for the slot is provided. When the slot is formed around the tensile strength body, the gripping portion feeds the tensile strength body toward the extrusion molding machine while gripping the tensile strength body, and the extrusion molding machine rotates a rotary die for coating the slot resin. Slots with grooves are formed.

JP-A-11-95077

The rotary die is rotated in order to form a groove in the slot by the extruder, and a force is applied to rotate the tensile body gripped by the grip portion by the rotation of the rotary die.
However, the cross-sectional outer shape of the resin coating layer of the strength member of Patent Document 1 is formed in a circular shape. For this reason, when the tensile strength body is gripped by the gripping portion, a slip occurs in the rotational direction of the tensile strength body between the tensile strength body and the gripping portion, and a groove having a desired reversal angle cannot be obtained. There is. This problem becomes more prominent as the manufacturing speed of the slot rod is increased, and when it is desired to further reduce the manufacturing time, an improvement is required to prevent the tensile body from slipping in the gripping portion.

  The present invention has been made in view of the above-described circumstances, and provides a method and an apparatus for manufacturing a slot rod for an optical cable that can prevent the tensile body from slipping in the rotational direction and have a predetermined groove angle. Objective.

An optical cable slot rod manufacturing method and manufacturing apparatus according to the present invention includes an optical cable formed by extruding a slot with a groove having a twist around a tensile strength body in which a resin coating layer is formed by extrusion molding around the tensile strength wire. Slot rod for manufacturing, forming a non-circular cross-sectional outer shape of the resin coating layer of the strength member, gripping the strength member with a gripping roller, and forming a groove in the slot with a slotted slot extruder the rotary die is rotated during the gripping rollers, against the force to attempt to rotate the tension member by rotation of the rotary die, is held by non-rotation of the strength members with respect to the gripping surface of the gripping roller, the tensile strength The body is fed towards the slotted slot extruder .
In addition, the groove of the slot with the groove is an SZ groove whose groove direction is alternately reversed, and the cross-sectional outer shape of the resin coating layer is an ellipse, a rectangle, a hexagon, or a notch that engages a protrusion on the gripping surface. It can be made into the shape which has.

  According to the manufacturing method and the manufacturing apparatus of the slot rod for an optical cable of the present invention, the gripping roller can grip the tensile body in a non-rotating manner that does not cause slipping with respect to the gripping surface. As a result, the slot angle can be accurately formed by the slot extruder.

It is explanatory drawing of the apparatus structural example which manufactures the slot rod for optical cables which concerns on this invention. It is explanatory drawing of the holding part shown in FIG. It is explanatory drawing of the holding state of the tensile strength body by the holding part shown in FIG. It is explanatory drawing of other embodiment of the holding part which concerns on this invention. It is sectional drawing of the optical cable which has a tensile body which coat | covered the resin coating layer.

  Embodiments of the present invention will be described with reference to the drawings. In the optical cable slot rod manufacturing apparatus shown in FIG. 1, the tensile strength wire 3a is supplied to the manufacturing line from the left side of FIG. 1, and the slot 2 is wound up on the right side of FIG. The manufacturing apparatus includes a tensile wire feeder 10, a coating layer forming machine 11, a cooling device 12, a gripping unit 13, a slot forming machine 14, a cooling device 15, a take-up machine 16, a groove angle measuring unit 17, a winder 18, and a control. The unit 19, the first drive motor 20, the second drive motor 22 and the like are included.

A tensile strength wire feeder 10 is provided on the most upstream side of the production line, and for example, a tensile strength wire 3a having a circular cross section is drawn out. As the tensile strength wire 3a, for example, a steel wire, a steel stranded wire, or the like can be used.
The tensile wire 3 a fed out from the tensile wire feeder 10 is fed into the coating layer forming machine 11. The coating layer forming machine 11 forms a tensile strength body 3 by coating a resin coating layer for improving adhesion to the slot resin around the tensile strength wire 3 a in the head.

Here, the cross-sectional outer shape of the resin coating layer of the strength member 3 molded by the coating layer molding machine 11 is a non-circular shape, for example, an ellipse shown in FIG. When the tensile strength line 3a is inserted into an elliptical shaped head, the tensile strength body 3 covered with a resin coating layer having an elliptical cross-sectional outer shape is formed. Thereafter, the strength member 3 is drawn out toward the cooling device 12.
The cooling device 12 cools the strength member 3 with water to solidify the resin coating layer. The strength member 3 is solidified to such an extent that it can be gripped by the grip portion 13, and is then fed out toward the grip portion 13.

The gripping part 13 has a pulley 30 and a plurality of gripping rollers 32. The plurality of gripping rollers 32 are juxtaposed along the traveling direction of the strength member 3. On the outer peripheral surface of the gripping roller 32, a gripping surface having a shape for gripping the strength member 3 in a non-rotating manner is formed along the circumferential direction of the gripping roller 32.
The gripping roller 32 sandwiches the tensile body 3 from both sides (left and right or up and down) and sends it to the next process while applying a constant pressure so that the tensile body 3 does not rotate. The pressure to the strength member 3 can be adjusted by the air pressure of the air cylinder, for example.

When forming an SZ-type groove, the pulley 30 is configured to efficiently form an SZ-type groove by rotating the gripping portions 13 alternately in the direction opposite to the rotating die as disclosed in Patent Document 1. .
The pulley 30 can be rotated by the power of the second drive motor 22 via the pulley 23, and the pulley 30 can rotate together with the gripping roller 32 with the strength member 3 as an axis. The second drive motor 22 is, for example, an AC servo motor, and the rotation amount, rotation direction, and rotation speed can be controlled. Thereby, the second drive motor 22 can alternately invert the grip 13 based on the drive signal from the controller 19.

When the gripping portion 13 rotates, the strength member 3 is fed toward the slot forming machine 14 while being twisted while being gripped by the gripping roller 32.
The slot molding machine 14 molds the slot 2 by extruding a resin for the slot around the strength member 3. The slot forming machine 14 has a head 41, a rotary die 42 and a pulley 43. The rotary die 42 is disposed in the head 41 and has a hole having a shape substantially equal to the cross-sectional outer shape of the slot 2 to be molded. A pulley 43 is formed at one end of the rotating die 42, and the rotating die 42 can rotate about the strength member 3 as an axis by the rotation of the pulley 43.

The pulley 43 can be rotated by the power of the first drive motor 20 via the pulley 21. Similar to the second drive motor 22, the first drive motor 20 is configured by, for example, an AC servo motor or the like, and can alternately invert and drive the rotary die 42 based on a drive signal from the control unit 19.
The slot 2 formed by the slot forming machine 14 is fed out toward the cooling device 15. As with the cooling device 12, the cooling device 15 cools the slot 2 with water and solidifies the slot. The solidified slot 2 is fed toward the take-up machine 16 and taken up at a constant speed.

  A groove angle measurement unit 17 is provided on the downstream side of the take-up machine 16. For example, when forming a bidirectionally twisted SZ type slot, the groove angle measuring unit 17 can measure the inversion angle of the SZ groove formed in the slot. The measurement result is output to the control unit 19, and the control unit 19 compares the reversal angle stored in the memory with the prescribed value of the reversal angle so that the reversal angle of the SZ groove falls within a predetermined range. A signal is output to the drive motor 20 and the second drive motor 22.

The slot rod that has passed through the groove angle measuring unit 17 is wound around a drum by a winder 18. The slot rod wound around the drum then becomes an optical cable through an optical fiber core wire receiving step, a presser winding tape winding step, and a sheath covering step.
By the way, when the SZ type slot is formed, the resin for the slot is pushed out around the strength member 3 while the rotary die 42 of the slot forming machine 14 is reversed left and right. At this time, the gripping unit 13 supplies the slot body 14 with the gripping roller 32 while gripping the strength member 3 so that the strength body 3 does not rotate with the rotation of the rotary die 42. At the same time, the pulley 30 is synchronized with the alternate reversal of the rotary die 42, and the phase of the rotary die 42 is changed by 180 ° and is rotated in the direction opposite to the rotational direction of the rotary die 42.

  FIG. 2 shows an example of the gripping roller 32 described above. For example, a set of support plates 31 are arranged on both sides of the strength member 3, and a plurality of gripping rollers 32 are arranged so that the gripping surface 33 is along the traveling direction of the strength member 3. For example, three sets of gripping rollers 32 are rotatably supported by a support plate 31 on both sides of the strength member 3. The end of each support plate 31 is connected to the pulley 30 described in FIG. 1, and the distance between the support plates 31 is adjusted by an air cylinder.

As shown in FIG. 3, the strength member 3 is composed of a strength line 3 a and a resin coating layer 3 b ₁ having an elliptical cross-sectional outer shape, and has an elliptical long diameter arranged in a direction connecting the gripping rollers 32. It is fed to the molding machine. The gripping surface 33 is configured, for example, in a shape that follows the outer shape of both ends of the long diameter, and has a curved groove in which the center of the gripping surface 33 is deepest. The strength member 3 is sandwiched between the gripping surface 33 and the gripping surface 33 facing each other, and is fed out while being reversed. As a result, it is possible to prevent the tensile body from slipping in the gripping portion, as in the case of gripping a tensile body having a circular cross-sectional outer shape, and to obtain a desired inversion angle constituting the SZ groove.

FIG. 4 is a diagram showing another embodiment. The tensile body 3 shown in FIG. 4A is composed of a tensile strength line 3a and a resin coating layer 3b ₂ having a square cross-sectional outer shape. The strength member 3 is drawn out to the slot forming machine in a posture in which one of the two diagonal lines constituting the quadrangle is arranged in a direction connecting the gripping rollers 32a. The gripping surface 33a in this case is configured to have a shape that follows the outer shape of a square corner portion, for example, and has a substantially square-shaped groove with the center of the gripping surface 33a being the deepest.

The strength member 3 shown in FIG. 4B is composed of a strength line 3a and a resin coating layer 3b ₃ having a hexagonal cross-sectional outer shape. The strength member 3 is drawn out to the slot forming machine in a posture in which two of the three diagonal lines constituting the hexagon are arranged in a direction connecting the gripping rollers 32b. The gripping surface 33b in this case is formed in a shape that follows the outer shape connecting the two corners of the hexagon, and has a substantially trapezoidal groove in which the center of the gripping surface 33b is flat.

The tensile body 3 shown in FIG. 4C includes a tensile strength line 3a and a resin coating layer 3b ₄ having a substantially circular cross-sectional outer shape. The resin coating layer 3b ₄ has two notches extending in the longitudinal direction and facing each other, and the strength member 3 is fed out to the slot molding machine in a posture in which each notch faces the gripping roller 32c. At the center of the gripping surface 33c, a protrusion 34 that engages with the notch is formed along the circumferential direction of the gripping roller 32c. Gripping surface 33c, for example, be configured in a shape to follow the contour of the resin-coated layer 3b _4, the center of the gripping surface 33c has a groove that is curved to project.

In this way, the tensile strength body is formed in an irregular shape other than a circle that is easily gripped by the gripping portion, and the gripping surface is also shaped in accordance with the outer shape of the resin coating layer of the tensile strength body. Therefore, it is possible to further prevent slippage between the tensile body and the gripping roller.
The shape of the gripping surface may not be a shape that follows the outer shape of the resin coating layer as long as the strength member can be gripped without rotation. In the above-described embodiment, the SZ type slot has been described as an example. However, the present invention can be applied to the case where a unidirectional twisted spiral groove is formed.

1 ... optical cable, 2 ... slots, 2a ... groove, 2b ... slots ribs, 3 ... strength member, 3a ... tensile strength _wire, 3b _1, 3b 2, _3b 3, 3b 4 _... resin coating layer, 4 ... optical fiber ribbon DESCRIPTION OF SYMBOLS 5 ... Press roll tape, 6 ... Sheath, 10 ... Tensile wire feeder, 11 ... Coating layer forming machine, 12, 15 ... Cooling device, 13 ... Holding part, 14 ... Slot forming machine, 16 ... Take-off machine, 17 ... Groove angle measurement unit, 18 ... winding machine, 19 ... control unit, 20 ... first drive motor, 21, 23, 30, 43 ... pulley, 22 ... second drive motor, 31 ... support plate, 32, 32a, 32b 32c, gripping rollers, 33, 33a, 33b, 33c, gripping surfaces, 34, projections, 41, heads, 42, rotating dies.

Claims (4)

A method for producing a slot rod for an optical cable, in which a grooved slot having a twist is extruded around a tensile body in which a resin coating layer is formed by extrusion molding around the tensile wire,
The resin coating layer of the strength member is formed in a non-circular cross-sectional shape, the strength member is gripped by a gripping roller, and is rotated when the groove is formed in the slot by the slotted slot extruder. Rotating the die, the gripping roller grips the strength member against the gripping surface of the gripping roller in a non-rotating manner against the force of rotating the strength member by the rotation of the rotating die ; A manufacturing method of a slot rod for an optical cable, characterized in that the tensile body is supplied toward the slotted slot extruder .   The method of manufacturing a slot rod for an optical cable according to claim 1, wherein the groove of the slot with the groove is an SZ groove whose groove direction is alternately reversed.   3. The optical cable slot rod according to claim 1, wherein a cross-sectional outer shape of the resin coating layer is an ellipse, a quadrangle, a hexagon, or a shape having a notch that engages with a protrusion on the gripping surface. Manufacturing method. An apparatus for producing a slot rod for an optical cable formed by extruding a slot with a groove having a twist around a tensile body in which a resin coating layer by extrusion molding is formed around a tensile wire,
A cross-sectional outer shape of the resin coating layer of the strength member is formed in a non-circular shape, a gripping roller that grips the strength member, and a slot with the groove that rotates a rotating die when the groove is formed in the slot. An extrusion molding machine, and the gripping roller grips the strength member against the gripping surface of the gripping roller against the force of rotating the strength member by rotating the rotary die. An apparatus for manufacturing a slot rod for an optical cable , wherein the tensile strength member is supplied toward an extrusion molding machine for the slotted slot.

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