CA1093877A - Optical waveguide cables - Google Patents
Optical waveguide cablesInfo
- Publication number
- CA1093877A CA1093877A CA304,916A CA304916A CA1093877A CA 1093877 A CA1093877 A CA 1093877A CA 304916 A CA304916 A CA 304916A CA 1093877 A CA1093877 A CA 1093877A
- Authority
- CA
- Canada
- Prior art keywords
- filament
- grooves
- plastics
- die
- extrusion
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 230000003287 optical effect Effects 0.000 title claims abstract description 46
- 229920003023 plastic Polymers 0.000 claims abstract description 16
- 239000004033 plastic Substances 0.000 claims abstract description 16
- 238000004519 manufacturing process Methods 0.000 claims abstract description 9
- 238000001125 extrusion Methods 0.000 claims description 22
- 239000000463 material Substances 0.000 claims description 7
- 238000000034 method Methods 0.000 claims description 7
- 230000000737 periodic effect Effects 0.000 claims 1
- 239000003000 extruded plastic Substances 0.000 abstract description 2
- 239000004698 Polyethylene Substances 0.000 description 6
- -1 polyethylene Polymers 0.000 description 6
- 229920000573 polyethylene Polymers 0.000 description 6
- 229910000831 Steel Inorganic materials 0.000 description 5
- 239000010959 steel Substances 0.000 description 5
- 229920001903 high density polyethylene Polymers 0.000 description 3
- 239000004700 high-density polyethylene Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- HSRJKNPTNIJEKV-UHFFFAOYSA-N Guaifenesin Chemical compound COC1=CC=CC=C1OCC(O)CO HSRJKNPTNIJEKV-UHFFFAOYSA-N 0.000 description 1
- 241001674048 Phthiraptera Species 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 239000012809 cooling fluid Substances 0.000 description 1
- 230000001066 destructive effect Effects 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
- B29D11/00—Producing optical elements, e.g. lenses or prisms
- B29D11/00663—Production of light guides
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/44—Mechanical structures for providing tensile strength and external protection for fibres, e.g. optical transmission cables
- G02B6/4401—Optical cables
- G02B6/4407—Optical cables with internal fluted support member
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/44—Mechanical structures for providing tensile strength and external protection for fibres, e.g. optical transmission cables
- G02B6/4479—Manufacturing methods of optical cables
- G02B6/4489—Manufacturing methods of optical cables of central supporting members of lobe structure
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Health & Medical Sciences (AREA)
- Ophthalmology & Optometry (AREA)
- Mechanical Engineering (AREA)
- Extrusion Moulding Of Plastics Or The Like (AREA)
Abstract
Abstract of the Disclosure An optical cable has a grooved central filament, the grooves following helical paths, the helices changing hand along the filament. In the manufacture of the filament, plastics is extruded past a fixed die and some way downstream, the filament is held and twisted first in one direction and then in the opposite direction so that the helical paths are introduced where the plastics exits the die. Dielectric optical waveguides are disposed in the grooves and the whole is surrounded by an extruded plastic sheath to produce an optical cable.
Description
This invention relates to a filament for use in optical cables, to optical cables utilizing the filament and to a method of manufacturing the ~ilament.
It has been previously proposed to manuFacture optical cable having a central strength member of, for example steel ;
wire, a plastics outer sleeving extruded ar~und the steel wire and a series of grooves formed in the surface of the plastic sleeving, each groove containing a dielectric optical waveguide.
In order to ensure that dielectric optical waveguides are not subject to destructive tensile and compressive stresses wherever the cable is bent, the grooves are made in helical form.
Thus at a curved part of a cable a dielectric optical waveguide experiences alternately compression and tension and over the length of the curve, the stresses at least partially cancel out.
The manuFacturing steps for such cable include production of a grooved, plastics-coated metal strength member to provide a central filament for the cable, and the laying of dielectric optical waveguides into the grooves in the central filament.
In the former, a known practice is to extrude the plastics through a rotating die, a servo mechanism being utilized to maintain the correct ratio of die angular velocity to the extrusion rate of filament in order to maintain the pitch of the helices within a predetermined range throughout the length of the central filament.
It is necessary to limit the extrusion rate in order to guard against adverse shear affects resulting when the plastics9 as it is extruded in one direction, is directed rapidly in a different direction.
Care must also be taken in choosing an extrusion ra~e to avoid collapse of the grooved structure immediately the malleable~ high temperature plastics exits from the die.
3U To lay dielectric optical waveguides into an . ~ , .
appropriately grooved central filament, a planetary stranding technique has been adopted. In such a technique for laying in, SAy ten dielectric optical waveguides, ten reels of dielectric optical waveguide are mounted on a rotatable jig with the central filament being led through the centre of the jig. The reels revolve around the longitudinally moving filament with an angular velocity commensurate with both the pitch of the helical grooves and the velocity of the central filament. In effect therefore a reel ~ ;
follows a groove around as the central filament is fed through the jig. A suitable locating device presses payed out dielectric optical waveguide into the grooves.
Rotation of the reels and their motion around the central filament does, however, introduce a twist into the laid dielectric optical waveguide which is unacceptable because of the internal stresses which result. To compensate for this the reels are themselves rotated so that the undesirable twist in the dielectric optical waveguide is pre-empted. The nature of the movement of the reels somewhat resembles a planet system and accounts for the name given to this technique.
It will be appreciated that a complex servo mechanism is required to correctly interrelate the speeds at which:-1) the central filament is fed through the jig;
It has been previously proposed to manuFacture optical cable having a central strength member of, for example steel ;
wire, a plastics outer sleeving extruded ar~und the steel wire and a series of grooves formed in the surface of the plastic sleeving, each groove containing a dielectric optical waveguide.
In order to ensure that dielectric optical waveguides are not subject to destructive tensile and compressive stresses wherever the cable is bent, the grooves are made in helical form.
Thus at a curved part of a cable a dielectric optical waveguide experiences alternately compression and tension and over the length of the curve, the stresses at least partially cancel out.
The manuFacturing steps for such cable include production of a grooved, plastics-coated metal strength member to provide a central filament for the cable, and the laying of dielectric optical waveguides into the grooves in the central filament.
In the former, a known practice is to extrude the plastics through a rotating die, a servo mechanism being utilized to maintain the correct ratio of die angular velocity to the extrusion rate of filament in order to maintain the pitch of the helices within a predetermined range throughout the length of the central filament.
It is necessary to limit the extrusion rate in order to guard against adverse shear affects resulting when the plastics9 as it is extruded in one direction, is directed rapidly in a different direction.
Care must also be taken in choosing an extrusion ra~e to avoid collapse of the grooved structure immediately the malleable~ high temperature plastics exits from the die.
3U To lay dielectric optical waveguides into an . ~ , .
appropriately grooved central filament, a planetary stranding technique has been adopted. In such a technique for laying in, SAy ten dielectric optical waveguides, ten reels of dielectric optical waveguide are mounted on a rotatable jig with the central filament being led through the centre of the jig. The reels revolve around the longitudinally moving filament with an angular velocity commensurate with both the pitch of the helical grooves and the velocity of the central filament. In effect therefore a reel ~ ;
follows a groove around as the central filament is fed through the jig. A suitable locating device presses payed out dielectric optical waveguide into the grooves.
Rotation of the reels and their motion around the central filament does, however, introduce a twist into the laid dielectric optical waveguide which is unacceptable because of the internal stresses which result. To compensate for this the reels are themselves rotated so that the undesirable twist in the dielectric optical waveguide is pre-empted. The nature of the movement of the reels somewhat resembles a planet system and accounts for the name given to this technique.
It will be appreciated that a complex servo mechanism is required to correctly interrelate the speeds at which:-1) the central filament is fed through the jig;
2) dielectric optical waveguide is payed out;
3) the jig is rotated, and
4) the reels are rotated.
The optical cable structure of the invention permits the simplification of operating techniques for manufacture of the cable.
In add;tion, contrasting with known helical - lay optical cable, the manner in which dielectric optical waveguides are layed up in the proposed structure inhibits the damage from being ~~` ~L~3~3 ~3 caused through the cable twisting.
According to a first aspect of the invention there is provided an elongate filament for an optical cable, the filament having a surface, which surface deFines a plurality of grooves, said grooves each having a form of a helix, each said helix changing hand along the filament.
In preferred embodiments of the filament, at least one complete pitch of a particular helix exists between each change of hand thereof and respective helices all change hand in the same sense at predetermined positions along the filament. It is preferred that the h lices change hand at regular intervals along the length of the filament. In a typical optical cable structure, the filament composition is high density polyethylene surrounding a central strength member, dielectric optical waveguides being positioned in the grooves, and an outer plastics sheath surrounding the filament.
In a second aspect of the invention, apparatus For making the filament comprises an extrusion unit for continuous extrusion of heated, malleable plastics material through a fixed die having a plurality of fingers to form said grooves, a twist unit located downstream of said extrusion unit, said twist unit having a reciprocally rotatably driveable hollow cylindrical member For receiving the extruded material with at least some oF the grooves engaging the member5 the twist unit being driveable to twist the extruded material thereby to introduce a helical form to the grooves where extruded material exits the extruded unit. A link mechanism interadjacent the extrusion unit and the twist unit can relate reciprocal rotation of the cylindrical member to the rate of extrusion oF said plastic material. The location of the twist unit along a feedpath for the extruded -filament is chosen to be where the filament is comparatively ri~id and can support the engagement of, ~` 3L~ 3~
for example, in~ardly pro~ecting fins on the cylindrical member within the grQoves. Such fins can have blades or wheels of sufficiently narrow thlckness that they may be inserted within the grooves.
Alternatively the filament is gripped by a plurality of resil;ent wheels rotatably mounted on a jig, itself having a centre of rotation coincident with a central axis of the filament. The resilient wheels are arranged to bear against the filament with sufficient pressure to grip the f;lament but insufficient pressure to permanently d;stort the grooves.
An embod;ment of the invention will be described by way of example with reference to the accompanying drawings, in which:-Figure 1 is a perspective view of a length of filament according to the invention;
Figure 2 is a schematic representation of apparatus for making such a filament and laying dielectric optical waveguides into grooves in the filament, Fig~res 3 and 4 are respectively a perspective view and an end view of part of the apparatus for twisting extruded material to produce the filament;
Figure 5 is a perspective view of apparatus for laying dielectric optical waveguides into the filamentj and Figure 6 is a scrap longitudinal sectional view of part of the laying apparatus of Figure 5.
Referring to the drawings in detail, a filament for an optical cable has a central steel wire strength member 1 and, extruded over the strength member 1, a sleeve 2 of high density polyethylene. Formed in the surface of the sleeve and extending throughout the length of the filament are a number, ~'.,.' :
~` ~L~ 3~'7~
in this case four, circumferentially spaced grooves 3a, 3b~ 3c and 3d. In use the grooves each accommodate a dielectric optical ~aveguide in a relatively loose fit, the.whole being surrounded by an extruded y;~
- 4a -,~ , .
, ~43~7~
plastics sheath (not shown). In order to guard against breakage of dielectric optical waveguides where the optical cable is bent, the grooves are made to follow a helical path around the longitudinal axis of a filament. However, as shown at positions ~ the various helical paths followed by the grooves change hand (left to right or right to left) or lay direction. The grooves 3 are advantageously distributed evenly around the filament so the changes of hand of the four helical paths take place at the same specific positions along the length of the filament. The grooves thus have a generally parallel disposition relative to one another. As is evident from Figure 1 the changes of hand take place at regular intervals along the filament.
Turning to Figure 2, there is shown a schematic representation of apparatus used in the manufacture of an optical cable utilizing the filament described. Basically the apparatus ~-comprises three units, an extrusion unit 5, a twist unit 6, and a laying-in unit 7. To manufacture, steel wire core 1 and a charge of high density polyethylene 8 are fed into an extrusion unit which includes a die 9 shown in greater detail in Figure 3. The polyethylene 8 is heated until it is malleable and then extruded around the steel wire core 1 through the die 9 which is shaped to Form grooves 10 in the polyethylene as it exits the extrusion unit 5. Some way downstream of the extrusion unit, the filament, having been cooled by a trough oF cooling fluid (not shown) becomes relatively rigid and enters the twist unit which is operable to twist the filament, therefore introducing the helical form to the grooves where the polyethylene exits the extrusion unit.
Downstream of the twist unit 6 is the laying-in unit at which dielectric optical waveguide 11 which is payed out from reels 12 is set into the grooves 3.
3'7~
Referring to the more detailed Figure 3, molten polyethylene is ex-truded through the die 9 which has four inwardly projecting straight-walled fingers 13 to form the grooves 3. A twist unit 6 comprises a mechanism having a central cylindrical bore through which the extruded filament is pulled, the mechanism having at one end a gear 14 which is reciprocally rotatable and is driven by a drive gear 15 which forms part of a drive train from the extrusion unit, this being shown schematically by arrows B and C
and drive shaft 16, the function of the drive train being to relate the speed of oscillation of the gear 14 to the extrusion rate of the extrusion unit 5. Alternatively the rates of extrusion and drive to the twist unit can be preset to obta;n the required groove characteristics without the drive train B and C.
Integral with, and adjacent gear 14, is a barrel member 16 having a series of four evenly circumferentially spaced slots 17 extending through its wall. Slidably mounted within the slots for limited radiam movement are four fins 18 having blades ;~
19 of thin cross-section at their inner edges which project into the barrel 16. Outer edges 20 of the fins 18 are biased radially inwardly by a spring 21.
In operation of the twist unit 6, the blades 19 interengage in respective ones of the four grooves 3 where the extruded plastics is relatively cool and rigid and the drive train, via the gear 14, drives the barrel 16 to kwist the filament 2. Since the extrusion unit does not rotate, the extruded polyethylene between the two units 5 and 6 undergoes a shear stress resulting in the grooves in the most malleable part of the polyethylene, i.e. as it exits from the extrusion unit 5, being deformed to provide the ;
helical character. The change in hand of the individual helices is achieved merely by reversing the drive direction of the drive train.
The blades 19 are in an alternative embodiment, (not shown), replaced by miniature wheels which run in the grooves 3 in the filament 2 with somewhat less friction than do the blades 19.
In another alternative (not shown) the fi1ament is gripped at its surface by three wheels of resilient composition. The arrangement is such that the wheels bear su-Fficiently strongly on the filament that it can be twisted by the twist unit but insuFficiently strongly for the grooved surface structure to be permanently distorted.
Figure 4 shows a practical embodiment of the unit 7 for laying dielectric optical waveguides 11 into the grooves 3 of a f;lament 2. Dielectric optical waveguide is payed out -From Four reels 12 which ~re evenly circumferentially spaced away from a path 21 along which the grooved filament 2 is drawn. The dielectric optical waveguides 11 are pulled from the reels by the movement of the filament itself as will be explained presently. The dielectric optical waveguides 11 pass through guide means comprising a pair of rotatable plates 22 and 23. The filament 2 is drawn through the centre of the two plateswhile the dielectric optical waveguides pass through the plates at circumferential evenly spaced apertures 24 and 25. The plate 23 is somewhat thicker than plate 22 and the apertures25 are lined with tubes 26 which project from the downstream side of the plate 23. The tubes 26 are inclined towards the axis oF the ~;
filament 2 and their ends 27 are flexible and pressed in-to respective ~-grooves 3 so that as dielectric optical waveguide is drawn from the tubes by the filament being drawn past the laying~in unit 7, the dielectric optical waveguides are automatically located in the bases of the grooves 3. To aid the drawing out of dielectric optical waveguide, the outlet ends of the tubes are tapered, the tapered surface facing radially outward. In addition, the inlet ends of each of the tubes can be formed with a mouthpiece (not shown) to ~L~3~3~ 7 reduce friction effects where dielectric optical wave~uide enters the tubes.
The circumferential position of the grooves 3, where they are engaged by tube ends 27, regulate the angular position of the plate 23~ A geared drive shown schematically as arrow D relates the rotation of plate 22 to that of plate 23.
In operation the movement of filament 2 past the tube ends 27 produces rotation of plate 23 determined by the number of times a helical groove 3 extends around the longitudinal axis of the filament 2 between adjacent changes of hand or lay direction.
The purpose of the second plate 22 is to prevent the Four fibres From contacting each other and the central filament. The latter is undesirable since friction ef-fects would make the pulling of fibre from the fixed reels 12 much more dif-ficult. The presence of the plate 22 permits a phased winding of the dielectric optical waveguides 11 around each other and the central filament 2, but withou~ there being any contact. I-F a number of turns are envisaged between each change of hand of the helical grooves 3 then a number of intermediate plates 22 can be sited between the plate 23 and the reels 12 with 20 an appropriate gear drive.
In the embodiment described the drive is such as to produce angular rotation of ~2 of plate 22 For every angular rotation of the plate 23.
.. . . ..
:
The optical cable structure of the invention permits the simplification of operating techniques for manufacture of the cable.
In add;tion, contrasting with known helical - lay optical cable, the manner in which dielectric optical waveguides are layed up in the proposed structure inhibits the damage from being ~~` ~L~3~3 ~3 caused through the cable twisting.
According to a first aspect of the invention there is provided an elongate filament for an optical cable, the filament having a surface, which surface deFines a plurality of grooves, said grooves each having a form of a helix, each said helix changing hand along the filament.
In preferred embodiments of the filament, at least one complete pitch of a particular helix exists between each change of hand thereof and respective helices all change hand in the same sense at predetermined positions along the filament. It is preferred that the h lices change hand at regular intervals along the length of the filament. In a typical optical cable structure, the filament composition is high density polyethylene surrounding a central strength member, dielectric optical waveguides being positioned in the grooves, and an outer plastics sheath surrounding the filament.
In a second aspect of the invention, apparatus For making the filament comprises an extrusion unit for continuous extrusion of heated, malleable plastics material through a fixed die having a plurality of fingers to form said grooves, a twist unit located downstream of said extrusion unit, said twist unit having a reciprocally rotatably driveable hollow cylindrical member For receiving the extruded material with at least some oF the grooves engaging the member5 the twist unit being driveable to twist the extruded material thereby to introduce a helical form to the grooves where extruded material exits the extruded unit. A link mechanism interadjacent the extrusion unit and the twist unit can relate reciprocal rotation of the cylindrical member to the rate of extrusion oF said plastic material. The location of the twist unit along a feedpath for the extruded -filament is chosen to be where the filament is comparatively ri~id and can support the engagement of, ~` 3L~ 3~
for example, in~ardly pro~ecting fins on the cylindrical member within the grQoves. Such fins can have blades or wheels of sufficiently narrow thlckness that they may be inserted within the grooves.
Alternatively the filament is gripped by a plurality of resil;ent wheels rotatably mounted on a jig, itself having a centre of rotation coincident with a central axis of the filament. The resilient wheels are arranged to bear against the filament with sufficient pressure to grip the f;lament but insufficient pressure to permanently d;stort the grooves.
An embod;ment of the invention will be described by way of example with reference to the accompanying drawings, in which:-Figure 1 is a perspective view of a length of filament according to the invention;
Figure 2 is a schematic representation of apparatus for making such a filament and laying dielectric optical waveguides into grooves in the filament, Fig~res 3 and 4 are respectively a perspective view and an end view of part of the apparatus for twisting extruded material to produce the filament;
Figure 5 is a perspective view of apparatus for laying dielectric optical waveguides into the filamentj and Figure 6 is a scrap longitudinal sectional view of part of the laying apparatus of Figure 5.
Referring to the drawings in detail, a filament for an optical cable has a central steel wire strength member 1 and, extruded over the strength member 1, a sleeve 2 of high density polyethylene. Formed in the surface of the sleeve and extending throughout the length of the filament are a number, ~'.,.' :
~` ~L~ 3~'7~
in this case four, circumferentially spaced grooves 3a, 3b~ 3c and 3d. In use the grooves each accommodate a dielectric optical ~aveguide in a relatively loose fit, the.whole being surrounded by an extruded y;~
- 4a -,~ , .
, ~43~7~
plastics sheath (not shown). In order to guard against breakage of dielectric optical waveguides where the optical cable is bent, the grooves are made to follow a helical path around the longitudinal axis of a filament. However, as shown at positions ~ the various helical paths followed by the grooves change hand (left to right or right to left) or lay direction. The grooves 3 are advantageously distributed evenly around the filament so the changes of hand of the four helical paths take place at the same specific positions along the length of the filament. The grooves thus have a generally parallel disposition relative to one another. As is evident from Figure 1 the changes of hand take place at regular intervals along the filament.
Turning to Figure 2, there is shown a schematic representation of apparatus used in the manufacture of an optical cable utilizing the filament described. Basically the apparatus ~-comprises three units, an extrusion unit 5, a twist unit 6, and a laying-in unit 7. To manufacture, steel wire core 1 and a charge of high density polyethylene 8 are fed into an extrusion unit which includes a die 9 shown in greater detail in Figure 3. The polyethylene 8 is heated until it is malleable and then extruded around the steel wire core 1 through the die 9 which is shaped to Form grooves 10 in the polyethylene as it exits the extrusion unit 5. Some way downstream of the extrusion unit, the filament, having been cooled by a trough oF cooling fluid (not shown) becomes relatively rigid and enters the twist unit which is operable to twist the filament, therefore introducing the helical form to the grooves where the polyethylene exits the extrusion unit.
Downstream of the twist unit 6 is the laying-in unit at which dielectric optical waveguide 11 which is payed out from reels 12 is set into the grooves 3.
3'7~
Referring to the more detailed Figure 3, molten polyethylene is ex-truded through the die 9 which has four inwardly projecting straight-walled fingers 13 to form the grooves 3. A twist unit 6 comprises a mechanism having a central cylindrical bore through which the extruded filament is pulled, the mechanism having at one end a gear 14 which is reciprocally rotatable and is driven by a drive gear 15 which forms part of a drive train from the extrusion unit, this being shown schematically by arrows B and C
and drive shaft 16, the function of the drive train being to relate the speed of oscillation of the gear 14 to the extrusion rate of the extrusion unit 5. Alternatively the rates of extrusion and drive to the twist unit can be preset to obta;n the required groove characteristics without the drive train B and C.
Integral with, and adjacent gear 14, is a barrel member 16 having a series of four evenly circumferentially spaced slots 17 extending through its wall. Slidably mounted within the slots for limited radiam movement are four fins 18 having blades ;~
19 of thin cross-section at their inner edges which project into the barrel 16. Outer edges 20 of the fins 18 are biased radially inwardly by a spring 21.
In operation of the twist unit 6, the blades 19 interengage in respective ones of the four grooves 3 where the extruded plastics is relatively cool and rigid and the drive train, via the gear 14, drives the barrel 16 to kwist the filament 2. Since the extrusion unit does not rotate, the extruded polyethylene between the two units 5 and 6 undergoes a shear stress resulting in the grooves in the most malleable part of the polyethylene, i.e. as it exits from the extrusion unit 5, being deformed to provide the ;
helical character. The change in hand of the individual helices is achieved merely by reversing the drive direction of the drive train.
The blades 19 are in an alternative embodiment, (not shown), replaced by miniature wheels which run in the grooves 3 in the filament 2 with somewhat less friction than do the blades 19.
In another alternative (not shown) the fi1ament is gripped at its surface by three wheels of resilient composition. The arrangement is such that the wheels bear su-Fficiently strongly on the filament that it can be twisted by the twist unit but insuFficiently strongly for the grooved surface structure to be permanently distorted.
Figure 4 shows a practical embodiment of the unit 7 for laying dielectric optical waveguides 11 into the grooves 3 of a f;lament 2. Dielectric optical waveguide is payed out -From Four reels 12 which ~re evenly circumferentially spaced away from a path 21 along which the grooved filament 2 is drawn. The dielectric optical waveguides 11 are pulled from the reels by the movement of the filament itself as will be explained presently. The dielectric optical waveguides 11 pass through guide means comprising a pair of rotatable plates 22 and 23. The filament 2 is drawn through the centre of the two plateswhile the dielectric optical waveguides pass through the plates at circumferential evenly spaced apertures 24 and 25. The plate 23 is somewhat thicker than plate 22 and the apertures25 are lined with tubes 26 which project from the downstream side of the plate 23. The tubes 26 are inclined towards the axis oF the ~;
filament 2 and their ends 27 are flexible and pressed in-to respective ~-grooves 3 so that as dielectric optical waveguide is drawn from the tubes by the filament being drawn past the laying~in unit 7, the dielectric optical waveguides are automatically located in the bases of the grooves 3. To aid the drawing out of dielectric optical waveguide, the outlet ends of the tubes are tapered, the tapered surface facing radially outward. In addition, the inlet ends of each of the tubes can be formed with a mouthpiece (not shown) to ~L~3~3~ 7 reduce friction effects where dielectric optical wave~uide enters the tubes.
The circumferential position of the grooves 3, where they are engaged by tube ends 27, regulate the angular position of the plate 23~ A geared drive shown schematically as arrow D relates the rotation of plate 22 to that of plate 23.
In operation the movement of filament 2 past the tube ends 27 produces rotation of plate 23 determined by the number of times a helical groove 3 extends around the longitudinal axis of the filament 2 between adjacent changes of hand or lay direction.
The purpose of the second plate 22 is to prevent the Four fibres From contacting each other and the central filament. The latter is undesirable since friction ef-fects would make the pulling of fibre from the fixed reels 12 much more dif-ficult. The presence of the plate 22 permits a phased winding of the dielectric optical waveguides 11 around each other and the central filament 2, but withou~ there being any contact. I-F a number of turns are envisaged between each change of hand of the helical grooves 3 then a number of intermediate plates 22 can be sited between the plate 23 and the reels 12 with 20 an appropriate gear drive.
In the embodiment described the drive is such as to produce angular rotation of ~2 of plate 22 For every angular rotation of the plate 23.
.. . . ..
:
Claims (5)
EXCLUSIVE PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:-
1. A method of making an elongate filament for an optical cable, the filament having a surface, which surface defines a plurality of grooves of helical form, said method comprising extruding plastics material through a fixed die formed with a multi-fingered aperture to form said grooved surface in the plastics extrusion and, remote from said die where the extrusion is relatively rigid, twisting the filament to introduce a helical form in the grooves as the extruded filament exits the die.
2. A method as claimed in claim 1, in which the plastics is extruded around a central stranded wire which is drawn through the die at a rate commensurate with said plastics extrusion.
3. A method as claimed in claim 1, particularly for making a filament in which the lay direction of the grooves change periodically along the filament and wherein at said location, the filament is periodically twisted firstly in one direction and subsequently in the other direction to modify said helical form to one having a periodic change in lay direction.
4. An elongate filament for an optical cable, the filament having a central stranded wire strength member surrounded by a plastics sheath, a plurality of grooves defined in an outer surface of the sheath, said grooves each having a helical form periodically changing lay direction along the filament.
5. An optical cable having a central filament as claimed in claim 4, dielectric optical waveguides being positioned in the grooves.
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA304,916A CA1093877A (en) | 1978-06-07 | 1978-06-07 | Optical waveguide cables |
| GB7919563A GB2023060B (en) | 1978-06-07 | 1979-06-05 | Optical cables |
| FR7914477A FR2431711B1 (en) | 1978-06-07 | 1979-06-06 | IMPROVED OPTICAL CABLE |
| JP7070579A JPS55597A (en) | 1978-06-07 | 1979-06-07 | Improvement in optical cable |
| DE19792923132 DE2923132C2 (en) | 1978-06-07 | 1979-06-07 | Method for producing a plastic thread for an optical cable and device for carrying out this method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA304,916A CA1093877A (en) | 1978-06-07 | 1978-06-07 | Optical waveguide cables |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1093877A true CA1093877A (en) | 1981-01-20 |
Family
ID=4111636
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA304,916A Expired CA1093877A (en) | 1978-06-07 | 1978-06-07 | Optical waveguide cables |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS55597A (en) |
| CA (1) | CA1093877A (en) |
| DE (1) | DE2923132C2 (en) |
| FR (1) | FR2431711B1 (en) |
| GB (1) | GB2023060B (en) |
Families Citing this family (24)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5744107A (en) * | 1980-08-29 | 1982-03-12 | Nippon Telegr & Teleph Corp <Ntt> | Optical fiber cable and its manufacture |
| FR2494452A1 (en) * | 1980-11-20 | 1982-05-21 | Cables De Lyon Geoffroy Delore | METHOD OF MANUFACTURING A FIBER OPTIC CABLE |
| FR2497963A1 (en) * | 1981-01-09 | 1982-07-16 | Cables De Lyon Geoffroy Delore | METHOD FOR MANUFACTURING OPTICAL FIBER CABLE |
| FR2500174A1 (en) * | 1981-02-17 | 1982-08-20 | Lignes Telegraph Telephon | SIMULTANEOUS INSTALLATION HEAD OF OPTICAL FIBERS IN A GROOVE CYLINDRICAL SUPPORT AND DEVICE FOR MANUFACTURING WIRING COMPONENTS COMPRISING SUCH A HEAD |
| FR2502346A1 (en) | 1981-03-20 | 1982-09-24 | Cables De Lyon Geoffroy Delore | DEVICE FOLLOWING NO HELICOIDAL GROOVES |
| JPS587607A (en) * | 1981-07-07 | 1983-01-17 | Sumitomo Electric Ind Ltd | Optical fiber composite overhead line and its manufacturing method |
| GB2110414B (en) * | 1981-11-24 | 1985-08-21 | Bicc Plc | An optical cable |
| JPS58180785A (en) * | 1982-04-16 | 1983-10-22 | Max Co Ltd | Electronic circuit for unloader of compressor |
| IT1152225B (en) * | 1982-05-31 | 1986-12-31 | Pirelli Cavi Spa | APPARATUS FOR THE MANUFACTURE OF A CABLE WITH OPTICAL FIBERS |
| JPS5912104U (en) * | 1982-07-14 | 1984-01-25 | 古河電気工業株式会社 | self-supporting optical cable |
| JPS60177312A (en) * | 1984-02-24 | 1985-09-11 | Dainichi Nippon Cables Ltd | Manufacture of optical fiber cable |
| IT1175835B (en) * | 1984-04-19 | 1987-07-15 | Pirelli Cavi Spa | SUBMARINE CABLE FOR FIBER OPTIC TELECOMMUNICATIONS |
| IT1177430B (en) * | 1984-12-17 | 1987-08-26 | Pirelli Cavi Spa | PROCEDURE AND EQUIPMENT FOR THE PRODUCTION OF A CORE PROVIDED WITH OPEN PROPELLER SLOTS FOR ELEMENTARY FIBER OPTIC CABLES |
| GB8432122D0 (en) * | 1984-12-19 | 1985-01-30 | Telephone Cables Ltd | Optical cables |
| FR2576425B1 (en) * | 1985-01-24 | 1989-05-19 | Pourtier Pere Fils Ets | SPEED REGULATOR SERVO DEVICE FOR A MACHINE FOR WINDING OPTICAL FIBERS ON A HELICOIDAL GROOVE JUNCTION |
| GB2181090B (en) * | 1985-10-02 | 1990-04-18 | Telephone Cables Ltd | Optical fibre cable |
| GB8600294D0 (en) * | 1986-01-07 | 1986-02-12 | Bicc Plc | Optical cable |
| GB2186520A (en) * | 1986-02-07 | 1987-08-19 | Austral Standard Cables Pty Lt | Manufacture of helically grooved optical cable core |
| US4813014A (en) * | 1986-04-14 | 1989-03-14 | Phi Technologies, Inc. | Digital audio memory system |
| GB8713792D0 (en) * | 1987-06-12 | 1987-07-15 | Bicc Plc | Elongate flexible core |
| JPH0750231B2 (en) * | 1987-12-25 | 1995-05-31 | 宇部日東化成株式会社 | Optical fiber carrying spacer |
| DE3913372A1 (en) * | 1989-04-24 | 1990-10-25 | Rheydt Kabelwerk Ag | OPTICAL CABLE |
| JP4933331B2 (en) * | 2006-04-04 | 2012-05-16 | 宇部日東化成株式会社 | Method and apparatus for manufacturing spiral spacer |
| CN114185141B (en) * | 2022-02-15 | 2022-06-10 | 长飞光纤光缆股份有限公司 | Framework groove type optical cable framework processing method and device and framework groove type optical cable |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1250478A (en) * | 1968-02-23 | 1971-10-20 | ||
| DE2449439C3 (en) * | 1974-10-15 | 1984-08-23 | Siemens AG, 1000 Berlin und 8000 München | Communication cables with light guides or light guide bundles as transmission elements |
| DE2511019C2 (en) * | 1975-03-11 | 1984-08-23 | Siemens AG, 1000 Berlin und 8000 München | Basic element for the construction of optical cables |
| FR2312788A1 (en) * | 1975-05-27 | 1976-12-24 | Lenoane Georges | Fibre optics transmission cable - has sheath and plastics core with spiral slots in which fibres are placed |
| FR2388931A1 (en) * | 1977-04-27 | 1978-11-24 | Lignes Telegraph Telephon | METHOD OF MANUFACTURING WIRING ELEMENTS CONTAINING OPTICAL FIBERS BY VERTICAL MACHINE |
-
1978
- 1978-06-07 CA CA304,916A patent/CA1093877A/en not_active Expired
-
1979
- 1979-06-05 GB GB7919563A patent/GB2023060B/en not_active Expired
- 1979-06-06 FR FR7914477A patent/FR2431711B1/en not_active Expired
- 1979-06-07 DE DE19792923132 patent/DE2923132C2/en not_active Expired
- 1979-06-07 JP JP7070579A patent/JPS55597A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| DE2923132C2 (en) | 1987-02-19 |
| JPS55597A (en) | 1980-01-05 |
| FR2431711B1 (en) | 1986-04-11 |
| FR2431711A1 (en) | 1980-02-15 |
| DE2923132A1 (en) | 1979-12-13 |
| GB2023060B (en) | 1983-02-02 |
| GB2023060A (en) | 1979-12-28 |
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