JPH0231362B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an apparatus for manufacturing optical cables.

[Prior Art] A central reinforcing member made of, for example, steel wire, an outer sleeve of plastic extruded around the steel wire, and a series of grooves formed in the surface of the plastic sleeve, each groove having a It has previously been proposed to produce optical cables that include optical waveguides therein.

In order to avoid destructive tensile and compressive stresses on the optical waveguide at the bends of the optical cable, the groove is made in a helical shape. Therefore, compressive force and tensile force are alternately generated in the optical waveguide at the bent portion of the optical cable, and the stress is canceled out at least to some extent in the entire bent portion.

In manufacturing such optical cables, a grooved, plastic-coated metal reinforcement member is fabricated to form the central filament of the optical cable, and an optical waveguide is then embedded within the groove of the central filament. The former step has traditionally been performed by extruding the plastic through a rotating die. A servomechanism was utilized to maintain the die rotation speed in the correct ratio to the filament extrusion speed to keep the helical pitch within a predetermined range over the length of the center filament. It is necessary to limit the extrusion speed to avoid deleterious shear effects caused by extruding the plastic in one direction and causing the plastic to rapidly turn in another direction. It is also important to choose the extrusion speed to avoid collapse of the fluted structure immediately after the flexible high temperature plastic exits the die.

Planetary spinning techniques have traditionally been employed to embed optical waveguides within a suitably grooved central filament. Using this technique, for example, to embed 10 optical waveguides, 10 reels of optical waveguides are attached to a rotating jig, and the central filament is passed through the center of the jig. The reel rotates around the longitudinally moving filament with an angular velocity commensurate with the pitch of the helical groove and the velocity of the central filament. The reel is thus shaped to follow the groove as the center filament is fed through the jig. A suitable positioning device embeds the emitted optical waveguide in the groove.

However, this is undesirable because the rotation of the reel around the central filament causes kinks in the embedded optical waveguide, thereby creating internal stresses. To compensate for this, the reel itself is rotated in such a way as to pre-empt any undesirable torsions in the optical waveguide. The nature of the reel movement is somewhat similar to that of a planetary system, which gives the technique its name.

The complex servo mechanism controls the following speeds: (1) the speed at which the central filament is fed through the jig, (2) the speed at which the optical waveguide is ejected, (3) the rotational speed of the jig, and ( 4) It will be appreciated that it is necessary to correlate correctly with the rotational speed of the reel.

The optical cable structure, which forms the subject of the applicant's patent application of the same date, simplifies the operating technology for the production of optical cables. The above patent application describes a filament for an optical cable having grooves on its surface, the grooves having a spiral shape, and each spiral changing direction along the filament. .

With this filament structure, the technique for embedding the optical waveguide in the groove of the filament is relatively simple.

[Problem to be Solved] An object of the present invention is to provide an optical cable manufacturing apparatus that allows an optical waveguide to be embedded in a groove of a filament relatively easily.

[Techniques for Solving Problems] According to the present invention, there is provided a sending means for sending out a filament formed on the outer periphery in a state in which a plurality of grooves in which optical waveguides are disposed are spirally formed and the direction is changed. , each has an optical waveguide that can be sent out,
a plurality of optical waveguide storage means provided around and fixed to the feed path of the filament; and around the feed path of the filament and centered on the feed path; a guide means that is rotatably arranged and positions the optical waveguide sent out from the optical waveguide storage means so as to be disposed in the groove of the filament, and is provided so as to correspond to at least one groove of the filament; a following member for rotating the guide means around the filament feeding path according to the locus of the groove when feeding the filament; and winding the optical cable with the optical waveguide disposed in the groove of the filament. An optical cable manufacturing apparatus is provided, comprising a winding means for taking the optical cable.

In one embodiment of the invention, the guide means for the optical waveguide comprises at least one plate rotatable about the filament feed path and provided with a plurality of holes at a distance from the center; a tube having one end connected to a hole formed in the plate and the other end inserted into a groove of the filament, the other end of the tube on the groove side of the filament following the trajectory of the groove; The tube also serves as a follower for rotating the plate, and is configured such that an optical waveguide passes through the hole in the plate and the tube, and is arranged in the groove of the filament. The plate may consist of two plates spaced apart in the direction of the filament feed path;
In this case, one end of the tube is directly connected to a hole formed in the downstream plate. Further, the follower member can be a rod having one end inserted into a groove of the filament and the other end engaging the plate, through which an optical waveguide guided into the groove of the filament passes. An opening may be formed for this purpose.

In yet another aspect of the present invention, the optical waveguide storage means includes a plurality of reels wound with optical waveguides, and can further include extraction means for pulling out the optical waveguides wound on the reels. Further, a holding means may be provided to support the optical waveguide pulled out by the pulling means in a state where no tension is applied to the optical waveguide.

[Examples] Examples of the present invention will be described below with reference to the accompanying drawings.

Referring to FIG. 1 in detail, a filament 2 for an optical cable has a central reinforcing member 1 made of steel wire and a sleeve 2a made of high-density polyethylene extruded onto the reinforcing member 1. A plurality, in this case four, of circumferentially spaced grooves 3a, 3b, 3c and 3d are formed in the surface of the sleeve and extend over the entire length of the filament. In use, one optical waveguide fits relatively loosely into each groove and is entirely surrounded by an extruded plastic sheath (not shown). To prevent damage to the optical waveguide at bends in the optical cable, the groove follows a helical path around the longitudinal axis of the filament. However, as shown in position 4, each groove changes its direction (left to right or right to left). 4
The grooves 3 are preferably distributed equidistantly around the filament so that the redirection of the helical path of the book occurs at the same location along the length of the filament. The grooves are thus substantially parallel to each other.

As is clear from FIG. 1, the changes in direction occur at regular intervals along the filament.

FIG. 2 schematically shows an apparatus used for manufacturing an optical cable using the above-described filament. Basically, this device consists of three units: an extrusion unit 5 and a torsion unit 6.
and an embedded unit 7. During production, the steel wire reinforcing element 1 and the raw material of high-density polyethylene 8 are fed into an extrusion unit with a die 9. The polyethylene is heated until it becomes flexible and then extruded around the steel wire reinforcing member 1 as it passes through a die 9. Although the shape of the die 9 is not shown, it is shaped to form a groove 3 in the polyethylene as it exits the extrusion unit 5. Somewhere downstream of the extrusion unit, the filament is placed in a tub of cooling fluid (not shown).
It has already been cooled inside and has become relatively hard, and enters the torsion unit 6 in this state. The twisting unit 6 acts to twist the filament, so that the groove on the polyethylene as it leaves the extrusion unit has a helical shape. The extrusion unit 5 and the twisting unit 6 thus constitute filament delivery means.

Downstream of the torsion unit 6 there is an embedding unit 7, in which the optical waveguide 11 ejected from the reel 12, which is an optical waveguide storage means, is embedded in the groove 3. A plurality of reels 12 are positioned around the filament feed path and fixed relative to the feed path.

In FIG. 3, the optical waveguide 11 is connected to the groove 3 of the filament.
An embodiment of an embedding unit 7 is shown for embedding in a. The optical waveguide is delivered from four reels 12 that are equally spaced in the circumferential direction from the path along which the grooved filament 2 is drawn. The optical waveguide 11 is pulled out of the reel by the movement of the filament itself, as explained below. The optical waveguide 11 passes through a second plate 22 and a first plate 23 which are rotatable around the feeding path of a pair of filaments. The filament 2 is drawn through the center of the two plates, and the optical waveguide is passed through equally spaced openings 24 and 25 at the periphery of the plates.
go through. The first plate 23 is somewhat thicker than the second plate 22, and the opening 25 is connected to one end of a tube 26 projecting from the downstream side of the plate 23. The tube 26 is inclined toward the axis of the filament 2, and its other end 27 is flexible and pushed into the respective groove 3. For this purpose, the optical waveguide 11 is connected to the tube 26 by the filament being drawn through the embedded unit 7.
When pulled out from the groove 3, the optical waveguide is automatically positioned at the bottom of the groove 3. In order to facilitate the extraction of the optical waveguide, the other end of the tube 26, ie, the exit end 27 of the optical waveguide, has a radially outwardly tapered surface as shown in FIG. 3A. Further, at the one end of each tube 26, that is, the entrance end of the optical waveguide, an optical waveguide is connected to the tube 26.
A mouthpiece (not shown) is formed to soften the frictional effects upon entry.

The angular position of the plate 23 is adjusted by the circumferential position of the groove 3 where it engages the outlet end 27 of the tube. That is, the tube 26 moves in the first direction according to the trajectory of the groove 3.
It also works as a follower member that rotates the plate 23. A gear drive mechanism, generally indicated by the symbol D, determines the rotation of the plate 22 relative to the rotation of the plate 23.

In operation, the filament 2 is at the outlet end 27 of the tube.
By passing through the spiral groove 3
The plate 23 rotates through an angle around the longitudinal axis of the filament 2 between one turning position and the next turning position. The purpose of the second plate 22 is to prevent the four optical waveguides from touching each other and the central filament. The latter contact is undesirable because its frictional effects make it increasingly difficult to withdraw the optical waveguide from the reel 12. The presence of the second plate 22 causes the optical waveguides 11 to be wound around each other and around the central filament 2 with a phase difference, but no contact occurs. If the helical groove 3 is designed to have several revolutions between each change of direction, a number of intermediate plates may be placed between the plate 23 and the reel 12 using a suitable gear drive mechanism.

In the embodiment described herein, the drive mechanism moves plate 22 through an angle θ/ each time plate 23 rotates an angle θ.
It is designed to rotate by 2.

As can be seen from the above description, the plates 23 and 22 are
Together with the tube 26, it constitutes a guide means for positioning the optical waveguide 11 sent out from the reel 12 so that it is disposed in the groove 3. The tube 26 also acts as a follower member for rotating the plate 23 around the filament feed path in accordance with the trajectory of the groove 3.

FIG. 4 schematically shows another cable manufacturing device using the filament of FIG.
The filament is drawn in the direction of arrow A past the optical waveguide storage means and extraction unit and through the center of the implantation unit and the taping unit.

Figures 5 to 7 (1st figure shown in Figures 1 to 3)
As shown in detail in Figure 1 (those corresponding to the embodiments are given the same reference numerals), the optical waveguide 11 comprises four optical waveguide storage means distributed close to the vertical plane containing the feeding direction of the filament 2. i.e. reel 1
It is kicked out from 2. The optical waveguide 11 is pulled off the reel by a pair of rollers 30 with slightly elastic surfaces. The roller 30 is the optical waveguide 11
Therefore, when one roller 30 is driven, the optical waveguide 11 is pulled out from the reel 12. That is, the roller 30 constitutes a pulling means for pulling out the optical waveguide wound on the reel. The optical waveguide downstream of the roller 30 passes through a fixed plate 31 with distributed holes 32 and is then routed to the embedded unit shown in detail in FIG. The driving speed of the rollers is such that each optical waveguide hangs between the roller 30 and the fixed plate 31. The drooping portion of the optical waveguide prevents undesirable tension on the optical waveguide when it is driven through the fixed plate 31. That is, the roller 30 and the fixed plate 31
acts as a holding means to support the optical waveguide in a state where no tension is applied to the optical waveguide. In the absence of rollers 30, the tension in the optical waveguide is determined by the degree of equilibrium of reel 12 and the friction of the reel bearings.
Since it is extremely difficult to maintain the reels in a permanently balanced state and to equalize the bearing friction of the reels, the absence of rollers 30 will reduce the The tensile stress will be different for each.

Downstream of the drawer unit is a recessed unit, shown in detail in FIG. Optical cables are run downstream of the taping unit (not shown)
For this purpose, the filament 2 is drawn through the center of the embedded unit, and the optical waveguide 11 is
is pulled through the distribution holes 32 of the fixed plate 31. The optical waveguide 11 passes through guiding means consisting of a rotatable plate 23 mounted on a support structure 34 via a thrust bearing, schematically indicated at 33. Hole 28 in which rods 37 are arranged in a circular manner
installed on. The outer end of each rod is provided with an aperture 40 through which the optical waveguide 11 passes. The rods 37 are inclined towards the axis of the filament 2, and the open portions of the rods 37 are located in the respective grooves 3. The optical waveguide passes freely through the circularly arranged holes 29 in the plate 23 and is positioned in the groove 3 upon exiting the opening 40 . In this way, the plate 23 constitutes a guiding means for positioning the optical waveguide 11, which is delivered together with the rod 37, so as to be placed in the groove 3. This embodiment is particularly suitable for use with plastic-coated optical waveguides. Such use reduces dynamic friction between the rod and the optical waveguide and also prevents coating transfer and clogging as the optical waveguide passes through the aperture.

Each rod 37 has a groove for receiving the end of a set screw 36 placed in a threaded hole inside plate 23. The position of the rod 37 within the plate 23 can therefore be varied to accommodate different sizes of filaments. Using the thrust bearing 33 to reduce the rotational friction of the plate 23
This is important considering that only a small amount of moment is available to rotate 3. This moment is obtained by the end of the rod 37 following the movement of the groove 3 of the filament 2. That is, the rod 37 moves the plate 23 according to the trajectory of the groove 3.
It also works as a follower member to rotate the.

As shown in FIG. 7, the taping unit 38 used is placed between the embedded unit 7 and the optical cable winding means (not shown). It has a drum 39 wound around. The drum 39 is mounted on a friction bearing 4 against a support 45.
It has 4. The stripping device is mounted for independent rotation and is adapted to be driven by a drive (indicated schematically by the symbol _D1 ) coming from the implantation unit. The stripping device is the central boss 46
It has two booms 41 and a pair of rings 42. One ring is located in the middle of the drum and the other ring is located upstream of the drum.

When the stripping device rotates about the axis of the filament 2, the tape is pulled out of the drum 39, which rotates accordingly against the friction bearing. The tape is moving filament 2
automatically spirals around the To accurately position the tape, the horn 47 tapers toward the wrapping location just downstream of the implantable unit. Tape 43 functions to hold the optical waveguide in place until the plastic coating is applied. This is particularly useful when winding the filament before coating it. In the wound state, the portion of the optical waveguide 11 facing the boss of the take-up reel receives a direct force that tends to cause the optical waveguide to protrude from the groove, but this is suppressed by the tape 43. be. As mentioned above, the tape creates tether points at the portions where it makes frictional contact with the optical waveguides, thereby preventing tension from being applied to the optical waveguides once embedded in their respective grooves.

Referring to FIG. 8 (corresponding to the above embodiments are given the same reference numerals),
The filament 2 is pulled in the direction of arrow A, past the reel 12 of the optical waveguide, past the roller 30, and into the embedding unit 7 and the taping unit 3.
8 (units 7 and 38 are shown schematically)
and the air jet device 48 .

Briefly, the roller 30 corresponds to that shown in FIG. Pull out the wave from the reel 12. The optical waveguides are fed into the embedding unit 7 with some slack to avoid tensile stresses, guided towards the respective groove 3 and then positioned within the groove.
Taping unit 38 downstream of the implant unit
Synthetic tape is wrapped twice around the cable structure,
The optical waveguide is held in place.

The driving force applied to the completed optical cable at position B is used to pull the filament 2 and the optical waveguide 11, either separately or together, through the various units, thus creating a tension force in the optical waveguide. cannot be avoided. Even if the tension is on the order of several tenths of a gram, it is desirable because it will sufficiently increase the attenuation rate when making optical waveguide optical cables with small diameters (125 microns or less) and low numerical apertures (<0.18). do not have. To reduce the tension on the optical cable as it exits the taping unit 38, the optical cable is routed to an air jet device 48.

The air jet device 48 consists of a pair of concentric tubes 49 and 5.
has 0. The inner diameter of the inner tube 50 is dimensioned so that it closes and surrounds the filament, but allows the filament into which the optical waveguide is inserted to run freely along its central axis. The space between the two pipes is sealed by an annular plug 51 at the upstream end. A mouthpiece 55 is provided in the plug 51 so that the filament can be easily inserted therein. At the downstream end, the outer tube 49 extends slightly beyond the inner tube 50. An air inlet port 52 is provided laterally from the outer tube wall by a cylindrical flange 53 for connection to a source of air pressure (not shown). Inner wall of tube 49 and wall 5
Fins or vanes 54 extend between the tubes and the outer wall of the tube to maintain the tubes concentrically separated.

In operation, compressed air is admitted from port 52 into the enlarged mixing chamber 56 between tubes 49 and 50. Because of the plug 51, compressed air escapes only from the other end of the air jet device 48. Therefore, in part C of the air passage, the air flows through the outer tube 4.
9 on the outside and the surface of the filament 2 on the inside. For this reason, the optical waveguide located on the surface, which is approximately 10 to 150 μm in diameter and therefore lightweight, is subjected to a frictional force that attempts to pull the optical waveguide in the optical cable feeding direction A. Further, as air flows over the surface, a Bernoulli quasi-vacuum state is generated in which the optical waveguide 11 tends to be lifted out of contact with the grooved filament 2. The combination of these effects causes the optical waveguide to be forced (by frictional air contact) to reposition itself so that the tension is released, removed, or, if desired, compression introduced. (due to reduced optical waveguide-groove contact pressure)
It becomes possible. The degree of tension reduction or sag introduced depends on the distance between the filament surface and the outer tube 49 and the distance over which the filament is affected by the air jet.

It has been found that the following dimensional specifications are effective in the manufacturing process using an air jet device.

1 The outer diameter (OD) of the central filament is 6.6mm
It has eight surface grooves into which the optical waveguide fits loosely.

2 The inner diameter (ID) of the inner tube is 8.5 mm and the outer diameter (OD)
is 9.5mm.

3 The outer tube has an inner diameter of 11.0 mm and an outer diameter of 12.8 mm.

4 The length of the protruding part of the outer tube is 6.0 mm.

The pressure of the supplied air and the properties of the optical waveguide and filament also influence the degree of possible reduction in tension.

Tension reduction is most easily achieved if the air jet is applied immediately after embedding the optical waveguide in the groove 3 of the central filament 2, but it is also possible to apply the air jet at other stages of assembly. .

For example, it is also possible to supply the optical waveguide 11 with air jets separately in the region between when the optical waveguide 11 is pulled out from the reel 12 and before it is embedded in the cable. Of course, it is necessary to reduce the size of the air jet device 48 to some extent.

[Effects of the Invention] In order to use a filament in which a spiral groove changes direction periodically, the present invention provides an optical waveguide storage means, a filament delivery means, and a filament winding means that are fixed to the filament feeding path. However, it is possible to arrange the optical waveguide in the groove of the filament without causing any undesirable twisting of the optical waveguide by simply arranging only the guide means for the optical waveguide so as to be rotatable in opposite directions alternately around the feed path. enable. In this way, since there are fewer moving mechanisms, the device can be simpler than conventional ones.

The present invention also provides a guide means rotatable around the filament feeding path for positioning the optical waveguide to be disposed in the groove of the filament, and a guiding means rotatable around the filament feeding path according to the trajectory of the groove of the filament during feeding of the filament. By using a following member for rotating the guide means, the guide means can be automatically rotated in alternating opposite directions depending on the longitudinal movement of the filament, thereby causing the optical waveguide to move around the filament. can be placed continuously and smoothly within the groove.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a length of grooved filament used to make optical cables. FIG. 2 is a schematic diagram of an apparatus for making a filament and embedding an optical waveguide in the groove of the filament. 3 and 3A are perspective views of one embodiment of an apparatus for inserting an optical waveguide into a filament, with a portion of the apparatus in cross-section.
FIG. 4 is a schematic diagram of a portion of another cable manufacturing apparatus used in making optical cables. Fifth
The figure is a perspective view of a device for extracting the optical waveguide from the reel and supplying it to the implantation unit. FIG. 6 is a partial cross-sectional view of a mechanism for embedding an optical waveguide into a groove of a filament. FIG. 7 is a partial cross-sectional view of a mechanism for taping an optical waveguide to a grooved filament. FIG. 8 is a schematic partial cross-sectional view of an air jet device for reducing tension in an embedded optical waveguide. 1... Reinforcement member, 2... Filament, 2a...
...Sleeve, 3...Groove, 5...Extrusion unit, 6
...Torsion unit, 7...Embedded unit, 11
... Optical waveguide, 12 ... Reel, 22 and 23
... Rotatable plate, 24 and 25 ... Opening, 2
6...tube, 27...end of tube, 28 and 29...
...hole, 30...roller, 31...fixing plate, 33...
... Thrust bearing, 34 ... Support structure, 37 ... Rod, 38 ... Taping unit, 39 ... Drum, 41 ... Boom, 42 ... Ring, 43 ...
...Tape, 44...Friction bearing, 47...Horn,
48...Air jet device, 49...Outer tube, 50
...Inner tube, 51...Plug, 52...Air inlet port, 54...Fin, 55...Mouthpiece.

Claims (1)

[Scope of Claims] 1. A sending means for sending out a filament formed on the outer periphery in a state in which a plurality of grooves each having an optical waveguide arranged therein are spirally shaped and the direction is changed; has,
a plurality of optical waveguide storage means provided around and fixed to the feed path of the filament; and around the feed path of the filament and centered on the feed path; a guide means that is rotatably arranged and positions the optical waveguide sent out from the optical waveguide storage means so as to be disposed in the groove of the filament, and is provided so as to correspond to at least one groove of the filament; a following member included in the guide means that rotates the guide means around the feeding path of the filament according to the locus of the groove when the filament is fed; and the optical waveguide is disposed in the groove of the filament. What is claimed is: 1. An optical cable manufacturing device comprising: a winding means for winding up an optical cable in a state where the optical cable is rolled up; 2. The guide means is rotatable around the filament feeding path and has at least one plate provided with a plurality of holes at positions spaced apart from the center, and one end is connected to the hole formed in the plate, a tube whose other end is inserted into a groove of the filament, the other end of the tube on the groove side of the filament follows the trajectory of the groove, and the tube serves as a following member for rotating the plate. also works, an optical waveguide passing through the hole in the plate and the tube,
2. The optical cable manufacturing apparatus according to claim 1, wherein the optical waveguide is arranged in a groove of the filament. 3. The guide means includes first and second plates that are rotatable around the filament feeding path and that are each provided with a plurality of holes at positions spaced apart from the center, and that are formed in the first plate. a tube whose one end is connected to the hole and whose other end is inserted into the groove of the filament, the other end of the tube on the groove side of the filament follows the trajectory of the groove, and the tube is connected to the groove of the filament. It also acts as a follower member for rotating the first plate, and the optical waveguide passes through the holes in the second and first plates and the tube, so that the optical waveguide is disposed in the groove of the filament. An optical cable manufacturing apparatus according to claim 1, characterized in that the optical cable manufacturing apparatus is configured as follows. 4. The guide means is rotatable around the filament feeding path and includes at least one plate provided with a plurality of holes at positions spaced apart from the center, through which the optical waveguide passes to guide the filament. The following member has one end inserted into the groove of the filament and the other end engaged with the plate, and the follower member is configured to move the following member according to the locus of the groove of the filament. The optical cable manufacturing apparatus according to claim 1, characterized in that the optical cable manufacturing apparatus is configured to rotate the plate. 5. The optical cable manufacturing apparatus according to claim 1, wherein the optical waveguide storage means includes a plurality of reels wound with optical waveguides. 6. The optical waveguide storage means includes a plurality of reels wound with optical waveguides, and a pull-out means for pulling out the optical waveguide wound on the reels, and provides the optical waveguide pulled out by the pull-out means to the guiding means. An optical cable manufacturing apparatus according to claim 1, characterized in that it is configured as follows. 7. The optical waveguide storage means includes a plurality of reels wound with optical waveguides, a pull-out means for pulling out the optical waveguide wound on the reels, and a means for supporting the optical waveguide pulled out by the pull-out means in a state where no tension is applied. 2. The optical cable manufacturing apparatus according to claim 1, further comprising: a holding means, and is configured to provide the optical waveguide supported by the holding means to the guiding means. 8. The optical cable manufacturing apparatus according to claim 4, wherein an opening is formed at one end of the following member, through which an optical waveguide guided to the groove of the filament passes.