The present disclosure relates to the field of optical fiber and, in particular, relates to a method for bundling optical fiber ribbons. The present application is based on, and claims priority from an Indian Application Number 202011042123 filed on 28 September 2020, the disclosure of which is incorporated herein.

BACKGROUND
Optical fiber cables have secured an important position in building optical network of modern communication systems across the world. Optical fiber cable consists of one or more optical fibers. Optical fibers use light to transfer information from one end of the optical fiber to other. Due to an overgrowing demand of the optical fibers, there is an extensive increase in usage of intermittently bonded ribbon cables. The intermittently bonded ribbon cables include ribbon bundles disposed within the optical fiber cables. The intermittently bonded ribbon cables comprise of optical fibers densely packed in the form of ribbons and helps in avoiding usage of loose tube structures, therefore, an efficient and compact bundling of optical fiber ribbons is required. The use of ribbons (i.e., intermittently bonded ribbons, rollable ribbons and bendable ribbons) enables the optical fiber cable to have more number of optical fibers within the same space thereby having large optical fiber packing density. The ribbons (i.e., intermittently bonded ribbons, rollable ribbons and bendable ribbons) usually have 6-24 optical fibers bonded together with a special material. These ribbons are placed inside the optical fiber cables in the form of ribbon bundles. However, several design and process changes are required at every stage of manufacturing of the intermittently bonded ribbon cables as compared to the conventional manufacturing process including loose tube structures. In an example, proper bundling of ribbons is needed to avoid any stress build-up on ribbon bundles that may lead to degradation of optical properties of the optical fibers. Also, bonding between the optical fibers needs to be strong to resist or avoid tear that arises during the handling of the ribbons and other properties since optical property degrades due to stress.
Also, existing patent prior art having publication number US10107980B1 teaches about the process of ribbon bundling but do not emphasize efficient packing configurations of the ribbons inside a bundle.
In light of the above-stated discussion, there exists a need for an efficient method for bundling of optical fiber ribbons.

OBJECT OF THE DISCLOSURE
A primary object of the present disclosure is to provide a method for bundling a plurality of optical fiber ribbons.
Another object of the present disclosure is to achieve efficient packaging of plurality of optical fiber ribbons in a bundle.

SUMMARY
In an aspect, the present disclosure provides a method of high density packing of a plurality of optical fiber ribbons in an optical fiber cable. The method includes bundling the plurality of optical fiber ribbons, wherein the bundling comprises bending each ribbon of the plurality of optical fiber ribbons in a near-circular shape and forming a plurality of bent ribbons and binding the plurality of bent ribbons to form one or more ribbon bundles for packing in the optical fiber cable. The plurality of optical fiber ribbons is an intermittently bonded ribbon or a tru-ribbon. Binding of the plurality of bent ribbons is done with one or more binders. Binder is a yarn or tape like flexible object that mechanically holds the plurality of bent ribbons by winding around them. The method further comprising arranging the plurality of bent ribbons in a predefined configuration such that each bent ribbon is in contact with at least two bent ribbons. The predefined configurations can be chosen from 2, 8, 14 for 24 ribbons bundle, 3, 9 for 12 ribbons bundle, 1, 6 for 7 ribbons bundle or another configuration depending upon number of the plurality of optical fiber ribbons. The plurality of optical fiber ribbons includes 4, 6, 12, 16, 24 or any other suitable number of fibers and the plurality of optical fiber ribbons has a pay-off tension in a range of 10-100 grams, preferably between 30 grams to 75 grams. This pay-off tension is sufficient to pull ribbon of up to 24 fibers without optical attenuations. One or more water swellable yarns can be placed along with the plurality of bent ribbons to form the one or more ribbon bundles. The plurality of optical fiber ribbons is bent in the near-circular shape with a diameter of 1-1.5mm.
These and other aspects herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the invention herein without departing from the spirit thereof.

STATEMENT OF THE DISCLOSURE
The present disclosure provides a method for bundling of a plurality of optical fiber ribbons. The plurality of optical fiber ribbons are bundled using coloured binders. The method includes a first step of passing the plurality of optical fiber ribbons through a cradle with ribbon spools. The cradle with ribbon spools provide lay length to the plurality of optical fiber ribbons. The method includes another step of passing the plurality of optical fiber ribbons through a former cum separator. The former cum separator keeps the plurality of optical fiber ribbons separated from each other. The former cum separator changes shape of the plurality of optical fiber ribbons from a flat shape into a round shape when the plurality of optical fiber ribbons pass through eyelets of the former cum separator. The method includes yet another step of passing the plurality of optical fiber ribbons through a bundling die. The method includes yet another step of passing the plurality of optical fiber ribbons through a binder unit. The binder unit binds the plurality of optical fiber ribbons using the coloured binders. The use of binders to bind a plurality of optical fiber ribbons saves space and enables reduction in diameter of an optical fiber cable in which the plurality of optical fiber ribbons are placed as compared to the optical fiber cable having lose tubes. The method includes yet another step of pulling the plurality of optical fiber ribbons from the binder unit using a capstan of capstan and dancer mechanism. The method includes yet another step of winding the plurality of fibers on a take up drum using dancer of the capstan and dancer mechanism.

BRIEF DESCRIPTION OF FIGURES
Having thus described the disclosure in general terms, reference will now be made to the accompanying figures, wherein:
FIG. 1 illustrates a block diagram of a bundling assembly that enables a method for bundling a plurality of optical fiber ribbons.
FIG. 2 illustrates a cross-sectional view of a former cum separator.
FIG. 3 illustrates a sectional view of a bundling die for bundling the plurality of optical fiber ribbons.
FIG. 4 illustrates different views of the bundling die.
FIG. 5 illustrates a flow chart of a method for manufacturing an optical fiber cable.
FIG. 6 illustrates an exemplary bundle of 24 ribbons.
FIG. 7 illustrates an exemplary bundle of 12 ribbons.
FIG. 8 illustrates an exemplary bundle of 7 ribbons.
It should be noted that the accompanying figures are intended to present illustrations of few examples of the present disclosure. These figures are not intended to limit the scope of the present disclosure. It should also be noted that accompanying figures are not necessarily drawn to scale.

DETAILED DESCRIPTION
In the following detailed description of the invention, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be obvious to a person skilled in the art that the invention may be practiced with or without these specific details. In other instances, well known methods, procedures and components have not been described in details so as not to unnecessarily obscure aspects of the invention.
Furthermore, it will be clear that the invention is not limited to these alternatives only. Numerous modifications, changes, variations, substitutions and equivalents will be apparent to those skilled in the art, without parting from the scope of the invention.
The accompanying drawings are used to help easily understand various technical features and it should be understood that the alternatives presented herein are not limited by the accompanying drawings. As such, the present disclosure should be construed to extend to any alterations, equivalents and substitutes in addition to those which are particularly set out in the accompanying drawings. Although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are generally only used to distinguish one element from another.
FIG. 1 illustrates a block diagram of a bundling assembly 100 that enables a method for bundling a plurality of optical fiber ribbons. The bundling assembly 100 includes a cradle with ribbon spools 102, a former cum separator 104, a bundling die 106, a binder unit 108, capstan and dancer mechanism 110, and a take up drum 112.
The plurality of optical fiber ribbons 602 may be intermittently bonded ribbons or tru-ribbons, which are bendable optical fiber ribbons. Each of the plurality of optical fiber ribbons includes a plurality of optical fibers. The plurality of fibers in a ribbon may be, but not limited to, 4, 6, 12, 16, 24 as it is not feasible to bend a ribbon having less than 4 optical fibers to obtain a near-circular shape. In addition, the ribbon having more than 24 optical fibers tend to have large bent diameter and may generate unutilised space. In general, optical fiber refers to a medium associated with transmission of information over long distances in the form of light pulses. In addition, optical fiber uses light to transmit voice and data communications over long distances. Typically, the plurality optical fibers is placed in parallel and bonded with special material intermittently along the longitudinal length and width, to convert group of optical fibers into intermittently bonded ribbons. Similarly, tru-ribbon uses multiple fibers with 200 micrometer of diameter, with a 250-micrometer pitch, followed by application of a flexible matrix material. The matrix takes a corrugated shape, leading to less space consumption than typical ribbon cables.
The bundling assembly 100 includes the cradle with optical fiber ribbon spools 102. The plurality of optical fiber ribbons passes through the cradle with ribbon spools 102. The cradle with ribbon spools 102 may rotate in clockwise direction. The cradle with ribbon spools 102 may rotate in anti-clockwise direction. The rotation of the cradle with ribbon spools 102 provides lay length to the plurality of optical fiber ribbons. Any number of ribbon spools may be used based on size or nature of an optical fiber cable to be manufactured.
Lay length of the plurality of optical fiber ribbons may have a range more than 1 meter. In addition, lay length of the plurality of optical fiber ribbons may of any suitable value. In general, lay length is a distance required to complete one revolution of a strand around longitudinal axis of any conductor. Further, a pay-off tension of each of the plurality of optical fiber ribbons may be in range of about 10 gram to 100 gram. Typically, the plurality of optical fiber ribbons become loose leading to loop formation and other corresponding problems if the pay-off tension is below 10 grams and if the pay-off tension in beyond 100 grams, optical attenuation of the plurality of optical fiber ribbons becomes high. Alternatively, the pay-off tension of the plurality of optical fiber ribbons may preferably be in the range of about 30 gram to 75 gram. Alternatively, the range of pay-off tension of each of the plurality of optical fiber ribbons may vary. Furthermore, the plurality of optical fiber ribbons may have a width of around 3mm.
The plurality of optical fiber ribbons passes through the former cum separator 104. The former cum separator 104 keeps the plurality of optical fiber ribbons separated from each other. In addition, the former cum separator 104 changes shape of the plurality of optical fiber ribbons from a flat shape into a near-circular shape when the plurality of optical fiber ribbons pass through eyelets of the former cum separator 104. The former cum separator 104 bends each ribbon of the plurality of optical fiber ribbons in the near-circular shape that may collectively be called as a plurality of bent ribbons. In an example, each ribbon that is comprising of 12 optical fibers, is bent in the near-circular shape with a diameter of 1-1.5mm. Beyond the diameter of 1.5mm, the ribbon may take an arc shape instead of near-circular shape thereby reducing efficiency. The diameter of the plurality of bent ribbons may vary depending upon the number of optical fibers used in making the optical fiber ribbon. The plurality of bent ribbons passes through the bundling die 106.
The bundling die 106 converges the plurality of bent ribbons and arranges the plurality of bent ribbons in a predefined configuration such that each bent ribbon is in contact with at least two other bent ribbons. The predefined configuration can be chosen from 2, 8, 14 for 24 ribbons bundle, 3, 9 for 12 ribbons bundle and 1, 6 for 7 ribbons bundle as these configurations are derived from the most efficient packing configurations of equal sized rigid circles circumscribed within a larger circle. Avoidance of using these configurations will lead to higher space occupancy and/or optical attenuation in the optical fibers. There may be any another suitable configuration depending upon the number of ribbons in a bundle. In an implementation, one or more water swellable yarns may be placed along with the plurality of bent ribbons.
The plurality of bent ribbons passes through the binder unit 108. In an implementation, the one or more water swellable yarns are placed along with the plurality of bent ribbons before passing through the binder unit 108. Alternatively, the one or more water swellable yarns are optional. Multiple methods can be used to place them along with the plurality of optical fiber ribbons. The binder yarn may be placed on a cop unit. In an another implementation, any other suitable material to mitigate water penetration may be used. The binder unit 108 may include one or more binders. The one or more binders may be placed on the plurality of bent ribbons to form one or more ribbon bundles 600. The binder unit 108 binds the plurality of bent ribbons. In an example, some binders of the one or more binders are wound around the plurality of bent ribbons in a clockwise helical manner. In addition, other binders of the one or more binders are placed in counter-clockwise helical manner around the plurality of bent ribbons. The binder unit 108 binds the plurality of bent ribbons using coloured binders. The use of coloured binders facilitates identification of the plurality of bent ribbons without using loose tube structure. The use of binders saves space and enables reduction in diameter of the optical fiber cable in which the plurality of optical fiber ribbons are placed. Each of the coloured binders may have a same binding pitch. Alternatively, each of the coloured binders may have a different binding pitch.
Lay length is provided to the bundled plurality of optical fiber ribbons to reduce stress on the optical fibers when tension is experienced by the bundled plurality of optical fiber ribbons. The binder unit 108 bundles the plurality of bent ribbons.
The bundling assembly includes the capstan and dancer mechanism 110. The capstan and dancer mechanism 110 includes a capstan and a dancer. In general, capstan is used for pulling an object. In addition, dancer is used for winding the object on any pipe or drum. The plurality of optical fiber ribbons along with the one or more binders of the binder unit 108 are pulled through the capstan of the capstan and dancer mechanism 110. The capstan of the capstan and dancer mechanism 110 pulls the plurality of optical fiber ribbons from the binder unit 108 with a tension greater than the theoretical tension. The theoretical tension being the sum of the pay-off tensions of all individual ribbons. The value of theoretical tension depends on number of the plurality of optical fiber ribbons in a bundle. Further, the plurality of optical fiber ribbons are winded up on the take up drum 112 with utilization of dancer of the capstan and dancer mechanism 110. The capstan pulls the plurality of optical fiber ribbons from the binder unit 108 and the plurality of optical fiber ribbons are then winded up on the take up drum 112 with tension less than the theoretical tension. In an example, if the number of the plurality of optical fiber ribbons in the bundle is 6, then the capstan pulls the plurality of optical fiber ribbons from the binder unit 108 with the tension more than 6*(Pay-off tension of a single ribbon).
Slope of conical shape of the bundling die 106 is defined as
(maximum distance of a ribbon from the centre of the forming tool)/(horizontal distance between bunching die and forming tool)
Conical shape of the bundling die 106 ensures that the plurality of optical fiber ribbons farthest from centre of the former cum separator 104 enters smoothly with support along walls inside the bundling die 106. A straight portion or land of about 1 millimetre is provided towards exit of the bundling die 106 to provide support to the bundled plurality of optical fiber ribbons.
FIG. 2 illustrates a cross-sectional view 200 of the former cum separator 104. The former cum separator 104 has a width W1, a width W2, a width W3 and a width W4. The width W1 of the former cum separator 104 is of about 90 millimeter. The width W2 of the former cum separator 104 is of about 110 millimeter. The width W3 of the former cum separator 104 is of about 130 millimeter. The width W4 of the former cum separator 104 is of 7 millimeter. The width W1, the width W2, the width W3 and the width W4 may vary.
The former cum separator 104 has a length L1, a length L2, and a length L3. The length L1 is of 18 millimeter. The length L1 may vary. The length L2 is of 45 millimeter. The length L2 may vary. The length L3 is of 90 millimeter. The length L3 may vary. The former cum separator 104 has a diameter D1, a diameter D2, and a diameter D3. The diameter D1 is of 21 millimeter. The diameter D1 may vary. The diameter D2 is of 37 millimeter. The diameter D2 may vary. The diameter D3 is of 53 millimeter. The diameter D3 may vary. The eyelet of the former cum separator 104 has a diameter D4 of 2.5 millimeter. The diameter D4 may vary. In an example, the diameter D4 of the eyelet may be reduced using ceramic fittings. The eyelet assists in maintaining a smooth surface for the optical fiber thereby reducing the damage to the optical properties of the optical fiber. The former cum separator 104 is a single unit. Alternatively, the former-cum-separator unit may also be divided into parts and placed in front of each cradle unit instead of a single unit.
FIG. 3 illustrates a sectional view 300 of the bundling die 106 for bundling the plurality of optical fiber ribbons. FIG. 4 illustrates different views 400 of the bundling die 106.
FIG. 5 illustrates a flow chart 500 depicting a method for manufacturing an optical fiber cable. The optical fiber cable comprises the one or more ribbon bundles 600 having the plurality of optical fiber ribbons 602 in the near-circular shape and is a high density cable. It may be noted that in order to explain the method steps of the flowchart 500, references will be made to the elements explained in FIG. 1.
At step 502, the method includes a first step of colouring the plurality of optical fibers with colouring ink. The coloring ink is coated over the plurality of optical fibers.
At step 504, the method includes another step of ribboning of the plurality of optical fibers. The plurality of optical fibers is grouped together to form the plurality of optical fiber ribbons. The plurality of optical fiber ribbons is an intermittently bonded ribbon, a tru-ribbon or the like.
At step 506, the method includes a third step of bundling the plurality of optical fiber ribbons for the optical fiber cable. The plurality of optical fiber ribbons is bundled and placed in the optical fiber cable. The bundling process includes bending each ribbon of the plurality of optical fiber ribbons in the near-circular shape that is collectively called as the plurality of bent ribbons, arranging the plurality of bent ribbons in the predefined configuration such that each bent ribbon is in contact with at least two bent ribbons and binding the plurality of bent ribbons to form the ribbon bundle for packing in the optical fiber cable.
At step 508, the method includes a fourth step of sheathing the ribbon bundle. Sheathing is done to protect the optical fiber cable from environmental conditions. Environmental conditions include but may not be limited to rainfall, snowfall, wind, and sunlight. In addition, the sheathing of the optical fiber cable is done to protect the optical fiber cable form external stresses and loads.
The various actions, acts, blocks, steps, or the like in the flow chart 500 may be performed in the order presented, in a different order or simultaneously. Further, some of the actions, acts, blocks, steps, or the like may be omitted, added, modified, skipped, or the like without departing from the scope of the invention.
FIG. 6 illustrates an exemplary bundle of 24 ribbons. FIG. 7 illustrates an exemplary bundle of 12 ribbons. FIG. 8 illustrates an exemplary bundle of 7 ribbons. FIGs 6-8 illustrate efficient bundling configurations e.g. for 24 ribbons, configuration is 2, 8, 14 that represents number of ribbons in innermost, middle and outermost layer respectively. Similarly, for n=12, configuration is 3, 9 and for n=7, configuration is 1, 6.
Advantageously, the present disclosure provides a compact, high density and space efficient packaging of ribbon bundles, where bending of the plurality of optical fiber ribbons can help in achieving better space utilization in the bundle as compared to stack of flat ribbons as flat ribbons cannot be bent.
It will be apparent to those skilled in the art that other alternatives of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention. While the foregoing written description of the invention enables one of ordinary skill to make and use what is considered presently to be the best mode thereof, those of ordinary skill will understand and appreciate the existence of variations, combinations, and equivalents of the specific aspect, method, and examples herein. The invention should therefore not be limited by the above described alternative, method, and examples, but by all aspects and methods within the scope of the invention. It is intended that the specification and examples be considered as exemplary, with the true scope of the invention being indicated by the claims.
Conditional language used herein, such as, among others, "can," "may," "might," "may," “e.g.,” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain alternatives include, while other alternatives do not include, certain features, elements and/or steps. Thus, such conditional language is not generally intended to imply that features, elements and/or steps are in any way required for one or more alternatives or that one or more alternatives necessarily include logic for deciding, with or without other input or prompting, whether these features, elements and/or steps are included or are to be performed in any particular alternative. The terms “comprising,” “including,” “having,” and the like are synonymous and are used inclusively, in an open-ended fashion, and do not exclude additional elements, features, acts, operations, and so forth. Also, the term “or” is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term “or” means one, some, or all of the elements in the list.
Disjunctive language such as the phrase “at least one of X, Y, Z,” unless specifically stated otherwise, is otherwise understood with the context as used in general to present that an item, term, etc., may be either X, Y, or Z, or any combination thereof (e.g., X, Y, and/or Z). Thus, such disjunctive language is not generally intended to, and should not, imply that certain alternatives require at least one of X, at least one of Y, or at least one of Z to each be present.
While the detailed description has shown, described, and pointed out novel features as applied to various alternatives, it can be understood that various omissions, substitutions, and changes in the form and details of the devices or algorithms illustrated can be made without departing from the scope of the disclosure. As can be recognized, certain alternatives described herein can be embodied within a form that does not provide all of the features and benefits set forth herein, as some features can be used or practiced separately from others.

,CLAIMS:CLAIMS
We Claim:

1. A method of high density packing of a plurality of optical fiber ribbons (602) in an optical fiber cable, comprising:
bundling the plurality of optical fiber ribbons (602), wherein the bundling comprises bending each ribbon of the plurality of optical fiber ribbons (602) in a near-circular shape and forming a plurality of bent ribbons and binding the plurality of bent ribbons to form one or more ribbon bundles (600) for packing in the optical fiber cable.

2. The method as claimed in claim 1, wherein the plurality of optical fiber ribbons (602) is an intermittently bonded ribbon or a tru-ribbon.

3. The method as claimed in claim 1, wherein binding of the plurality of bent ribbons is done with one or more binders.

4. The method as claimed in claim 1 further comprising arranging the plurality of bent ribbons in a predefined configuration such that each bent ribbon is in contact with at least two bent ribbons.

5. The method as claimed in claim 1, wherein the predefined configurations can be chosen from 2, 8, 14 for 24 ribbons bundle, 3, 9 for 12 ribbons bundle, 1, 6 for 7 ribbons bundle or another configuration depending upon number of the plurality of optical fiber ribbons.

6. The method as claimed in claim 1, wherein the plurality of optical fiber ribbons includes 4, 6, 12, 16, 24 or any other suitable number of fibers and the plurality of optical fiber ribbons has a pay-off tension in a range of 10-100 grams, preferably between 30 grams to 75 grams.

7. The method as claimed in claim 1, wherein one or more water swellable yarns can be placed along with the plurality of bent ribbons to form the one or more ribbon bundles.

8. The method as claimed in claim 1, wherein the plurality of optical fiber ribbons is bent in the near-circular shape with a diameter of 1-1.5mm.

9. An optical fiber cable, comprising:
one or more ribbon bundles (600), wherein the one or more ribbon bundles comprises a plurality of optical fiber ribbons (602) bent in a near-circular shape.

10. The optical fiber cable as claimed in claim 9, wherein the plurality of optical fiber ribbons is an intermittently bonded ribbon or a tru-ribbon.

11. The optical fiber cable as claimed in claim 9, wherein binding of the plurality of bent ribbons is done with one or more binders.

12. The optical fiber cable as claimed in claim 9, wherein the plurality of bent ribbons is arranged in a predefined configuration such that each bent ribbon is in contact with at least two bent ribbons.

13. The optical fiber cable as claimed in claim 9, wherein the predefined configurations can be chosen from 2, 8, 14 for 24 ribbons bundle, 3, 9 for 12 ribbons bundle, 1, 6 for 7 ribbons bundle or another configuration depending upon number of the plurality of optical fiber ribbons.

14. The optical fiber cable as claimed in claim 9, wherein the plurality of optical fiber ribbons includes 4, 6, 12, 16, 24 or any other suitable number of fibers and the plurality of optical fiber ribbons has a pay-off tension in a range of 10-100 grams, preferably between 30 grams to 75 grams.

15. The optical fiber cable as claimed in claim 9, wherein one or more water swellable yarns can be placed along with the plurality of bent ribbons to form the one or more ribbon bundles.

16. The optical fiber cable as claimed in claim 9, wherein the plurality of optical fiber ribbons is bent in the near-circular shape with a diameter of 1-1.5mm.