Patent Description:
This application claims the benefit of <CIT> and an <CIT>.

With technological and scientific advancements, various modern communication technologies have been introduced and employed. One of the most important modern communication technologies is optical fiber communication technology using a variety of optical fiber cables. The optical fiber cables are widely used for communication to meet the increasing demands of end-users. To meet the increasing demands, installation of the optical fiber cables at a rapid pace becomes essential. The optical fiber cables for telecommunication application are installed in ducts. The installation of the optical fiber cables in the ducts is mostly performed using a blowing method, wherein, the blowing method to install the optical fiber cables in the ducts is dependent on a plurality of factors. The plurality of factors includes mass of the optical fiber cable, friction, stiffness, and the like. The blowing method enables installation of the optical fiber cable using pressurized air combined with additional mechanical pushing force that is called "blowing".

In general, the blowing method is the process of installation of the optical fiber cable into a pre-installed duct. The blowing is performed by injecting pressurized air inlet of the pre-installed duct before the optical fiber cable is pushed into the pre-installed duct. The pressurized air flows at high speed through the pre-installed duct and along the optical fiber cable. Also, pushing force is applied near the optical fiber cable inlet by a pushing device. The optical fiber cable includes uni-tube, multi-tube, unarmoured, armoured, micro duct cable, and the like. However, conventional structure of optical fiber cable makes it inefficient to allow pressurized air to blow the optical fiber cable in the pre-installed duct. In addition, the conventional optical fiber cable resists the pushing force due to higher coefficient of friction. Further, the conventional optical fiber cable has a higher number of contact points with the pre-installed duct. Furthermore, the conventional optical fiber cable has heavy weight.

Additionally, strength members are one of the important components of the optical fiber cable. The purpose of the strength members is to provide the optical fiber cable rigidity, bend resistance, mechanical strength and ease in blowing. A strength member can be installed either at a center of the optical fiber cable or embedded inside the sheath of the optical fiber cable. The strength member embedded inside the sheath is normally preferred over a central strength member for making a high density optical fiber cable as there is more space available in the center. After embedding the strength member in the sheath of the optical fiber cable, often water penetration occurs through the embedded strength member. The main reason is, during the embedding of the strength member inside the sheath, some clearance remains between the strength member and the sheath due to manufacturing tolerances. Generally, the water may penetrate even through a clearance of a few dozen microns. A water penetration test of the optical fiber cable is often carried out to assess the ability of the optical fiber cable to resist the water penetration in the optical fiber cable. Such water penetration assessments are necessary because water once penetrated through the clearance between the strength member and the sheath due to manufacturing tolerances, may travel to optical fiber junction boxes and may degrade optical properties of the components such as optical fibers.

Also, water penetration through a length of the optical fiber cable further leads to degradation of other components of the optical network.

A prior-art reference " <CIT> " discloses an optical fiber cable having a plurality of ribs on the surface of the optical fiber cable for improved blowing performance, however the ribs are of the same height. Another prior art, <CIT>, discloses optical fiber unit with respect to the application as to which diameter-narrowing and weight reduction of an optical fiber unit are requested/required. Another prior art, <CIT>, discloses the optical fiber cable used for premises wiring such as a building/bill. Another prior art, <CIT>, discloses a light having a tensile strength line arranged in the center, a plurality of grooves for accommodating optical fibers provided on the outer periphery by a thermoplastic resin, and a spiral shape in which the grooves are alternately inverted. Another prior art, <CIT>, discloses optical fiber cables having a central strength member encircled by a circumferentially continuous jacket or sheath which has therein at least one longitudinally extending chamber or duct which receives an optical fiber or optical fibers, the jacket being manually separable from the strength member. Another prior art, <CIT>, discloses the stranded type air-blowing optical cable that declines that a kind of surface has concavo-convex groove.

In view of the aforementioned discussion and prior-art reference, there is an urgent need for a technical solution that overcomes the above stated limitations of the prior arts of the conventional optical fiber cable. Hence, the present disclosure focuses on a ribbed and grooved cable having embedded strength members with water blocking coating. Any references to methods, apparatus or documents of the prior art are not to be taken as constituting any evidence or admission that they formed, or form part of the common general knowledge.

The present invention provides a ribbed and grooved cable having embedded strength members with water blocking coating according to claim <NUM>.

According to the claimed invention the ribbed grooved optical fiber cable includes a core with a plurality of optical fibers, a sheath enveloping the core and the sheath has an outer surface and an inner surface, the outer surface of the sheath has a plurality of external ribs and a plurality of external grooves and one or more strength members embedded in the sheath. A plurality of ribs and grooves on an internal surface of the sheath, wherein the plurality of ribs have variable height. The one or more strength members are coated with a water blocking coating material having at least one of an ultraviolet (UV) curable water swellable resin composition and a layer of ethylene acrylic acid (EAA).

According to the second aspect of the present disclosure, the UV curable water swellable resin composition includes acrylic acid, phenyl bis(<NUM>,<NUM>,<NUM>-trimethylbenzoyl)-phosphine oxide and oxybis(methyl-<NUM>,<NUM>-ethanediyl) diacrylate. In accordance with an embodiment of the present disclosure, the UV curable water swellable resin composition is applied directly on the one or more strength members or above a thin layer of ethylene acrylic acid (EAA). In accordance with an embodiment of the present disclosure, the UV curable water swellable resin composition coated one or more strength members are passed through one or more UV chambers to cure the UV curable water swellable resin composition.

According to the third aspect of the present disclosure, the water blocking coating material applied over the one or more strength members has a thickness of <NUM>±<NUM> microns. In accordance with an embodiment of the present disclosure, the one or more strength members are made of a fiber reinforced plastic (FRP), an aramid reinforced plastic (ARP) or alike material.

According to the fourth aspect of the present disclosure, the plurality of external ribs are arranged alternately throughout the outer surface of the sheath of the ribbed grooved optical fiber cable.

According to the fifth aspect of the present disclosure, the plurality of external ribs having the first height and the second height are arranged in such a way that the plurality of external ribs having the first height and the plurality of external ribs having the second height are positioned diagonally opposite to each other. In accordance with an embodiment of the present disclosure, the plurality of external ribs of the sheath have at least two heights including a first height and a second height.

According to the sixth aspect of the present disclosure, the first height is in a range of <NUM> millimeters to <NUM> millimeters and the second height is in the range of <NUM> millimeters to <NUM> millimeters. In accordance with an embodiment of the present disclosure, the plurality of external ribs and the plurality of external grooves has a width in the range of <NUM> millimeters to <NUM> millimeters.

According to the seventh aspect of the present disclosure, the shape of the plurality of external ribs and the plurality of external grooves is any rectangular shape with rounded edges, a pointy triangle shape, a circular shape, a curve-type shape or any suitable shape.

According to the eighth aspect of the present disclosure, the sheath and the plurality of external ribs are made of a same material. In accordance with an embodiment of the present disclosure, the sheath and the plurality of external ribs are made of different materials.

According to the ninth aspect of the present disclosure, the ribbed grooved optical fiber cable has a diameter in the range of <NUM> to <NUM> millimeters and has a blowing of more than <NUM> meters in a duct with an inner diameter of <NUM> millimeters and an outer diameter of <NUM> millimeters.

According to the tenth aspect of the present disclosure, the plurality of internal ribs and the plurality of internal grooves are arranged alternately throughout the inner surface of the sheath. In accordance with an embodiment of the present disclosure, the plurality of internal grooves is made to reduce weight of the ribbed grooved optical fiber cable. According to an aspect of the present disclosure, a shape of the plurality of internal ribs and the plurality of internal grooves has a rectangular shape with rounded edges, a pointy triangle shape, a circular shape, a curve-type shape or alike shape. In accordance with an embodiment of the present disclosure, the plurality of internal ribs has a height in a range of <NUM> millimeter to <NUM> millimeter. In accordance with an embodiment of the present disclosure, the plurality of internal ribs and the plurality of internal grooves has a width in the range of <NUM> millimeter to <NUM> millimeters.

According to another aspect of the present disclosure, the sheath used in the ribbed grooved optical fiber cable passes a water penetration test at <NUM> bar pressure water-head applied to a <NUM> meter optical cable for at least <NUM> hours.

The foregoing solutions of the present disclosure are attained by employing a ribbed grooved optical fiber cable with embedded strength members coated with a water blocking coating material.

To describe the technical solutions in the embodiments of the present disclosure or in the prior art more clearly, the following briefly describes the accompanying drawings required for describing the embodiments or the prior art. The accompanying drawings in the following description merely show some embodiments of the present invention which is defined by the attached claims.

The ribbed and grooved cable and the sheath illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures.

It should also be noted that the accompanying figure is not necessarily drawn to scale.

Those skilled in the art will be aware that the present disclosure is subject to variations and modifications other than those specifically described. It is to be understood that the present invention includes all such variations and modifications that fall within the scope of the attached claims.

For convenience, certain terms employed in the specification, and examples are collected here. These definitions should be read in the light of the remainder of the disclosure and understood as by a person of skill in the art. The terms used herein have the meanings recognized and known to those of skill in the art, however, for convenience and completeness, particular terms and their meanings are set forth below.

The terms "comprise" and "comprising" are used in the inclusive, open sense, meaning that additional elements may be included. It is not intended to be construed as "consists of only". Throughout this specification, unless the context requires otherwise the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated element or step or group of element or steps but not the exclusion of any other element or step or group of element or steps.

The term "including" is used to mean "including but not limited to". "Including" and "including but not limited to" are used interchangeably.

<FIG> illustrates a design of a sheath of an optical ribbed and grooved <NUM> having a plurality of ribs and a plurality of grooves on an external surface of the sheath and strength members embedded inside the sheath in accordance with the first configuration which lies outside the scope of the present invention.

In particular, the cable is termed as a ribbed and grooved optical fiber cable <NUM> as it has a ribbed and grooved sheath. Moreover, the ribbed and grooved optical fiber cable <NUM> includes a plurality of optical fibers (not shown) and the sheath <NUM> having a plurality of ribs <NUM> and a plurality of grooves <NUM>. Moreover, the sheath <NUM> has a plurality of strength members <NUM> embedded into it.

The sheath <NUM> includes an inner surface and an outer surface. In particular, sheath is an outer layer of a ribbed grooved optical fiber cable <NUM> protects the optical fiber cable from environmental conditions. In addition, the environment conditions include but may not be limited to rainfall, sunlight, snowfall, and wind. Moreover, the sheath <NUM> of the ribbed and grooved optical fiber cable <NUM> encloses the plurality of optical fibers concentrically along a length of the optical fiber cable. Further, the sheath has an outer surface and an inner surface. The outer surface of the sheath <NUM> of the ribbed and grooved optical fiber cable <NUM> includes the plurality of ribs <NUM> and the plurality of grooves <NUM>. The plurality of ribs <NUM> and the plurality of grooves <NUM> are formed on the outer surface of the sheath <NUM>, thus called as a plurality of external ribs and a plurality of external grooves throughout the description.

In an embodiment, the number of the plurality of ribs <NUM> is the same as the number of the plurality of grooves <NUM>. In one embodiment, each of the plurality of ribs <NUM> has depth in range of about <NUM> millimeter to <NUM> millimeters. In another embodiment of the present disclosure, the plurality of ribs <NUM> has depth in range of about <NUM> millimeter to <NUM> millimeter.

In yet another embodiment, depth of the plurality of ribs <NUM> may vary. In an embodiment, the plurality of ribs <NUM> has width in range of about <NUM> millimeter to <NUM> millimeter. In another embodiment, the plurality of ribs <NUM> has width in range of about <NUM> millimeter to <NUM> millimeter. In yet another embodiment, width of the plurality of ribs <NUM> may vary. In one aspect, the plurality of ribs <NUM> may be <NUM>. In another aspect of the present disclosure, the plurality of ribs <NUM> may vary depending upon the width of the plurality of ribs <NUM>. In an embodiment, the number of grooves <NUM> is <NUM>. In another embodiment, the plurality of grooves <NUM> may vary depending upon width of the plurality of grooves <NUM>.

In one aspect, the area of the ribbed and grooved optical fiber cable <NUM> corresponding to <NUM> ribs and <NUM> grooves is about <NUM> millimeter square. In another aspect, the area of the cable may vary depending upon internal diameter of the cable, external diameter of the cable, number of the plurality of ribs <NUM> and the plurality of grooves <NUM>.

In an aspect, the ribbed and grooved optical fiber cable <NUM> has deformation of about <NUM> under crushing load at <NUM> Newton per <NUM> millimeter. In another aspect, the deformation of the ribbed and grooved optical fiber cable <NUM> may vary. In particular, deformation of the ribbed and grooved optical fiber cable <NUM> may vary depending upon a plurality of parameters. And, the plurality of parameters includes but may not be limited to number of the plurality of ribs <NUM> and the plurality of grooves <NUM>, width and height of the plurality of ribs <NUM> and the plurality of grooves <NUM>, inside and outside diameter of the ribbed and grooved optical fiber cable <NUM>, number of the plurality of strength members <NUM> in the sheath <NUM>, and material grade of the ribbed and grooved optical fiber cable <NUM>.

The plurality of ribs <NUM> and the plurality of grooves <NUM> reduce coefficient of friction between the sheath <NUM> and a duct. In an embodiment the plurality of ribs <NUM> and the plurality of grooves <NUM> are arranged alternately to each other on the outer surface of the sheath <NUM>. In an exemplary example, a groove of the plurality of grooves <NUM> is present on both sides of each rib of the plurality of ribs <NUM>. In another exemplary example, a rib of the plurality of ribs <NUM> is present on both sides of each groove of the plurality of grooves <NUM>. In an embodiment falling outside the scope of the present invention, the height of each of the plurality of ribs <NUM> is equal. Alternatively, in another embodiment, height of each of the plurality of grooves <NUM> is equal.

In an embodiment, the ribbed and grooved optical fiber cable <NUM> is installed into the duct using a blowing process. Particularly, the duct surrounds the ribbed and grooved optical fiber cable <NUM>. The blowing process to install the ribbed and grooved optical fiber cable <NUM> in the duct is dependent on a plurality of factors. Moreover, the plurality of factors includes mass of the ribbed and grooved optical fiber cable <NUM>, friction between the ribbed and grooved optical fiber cable <NUM> and the duct, stiffness of the ribbed and grooved optical fiber cable <NUM>, and the like. Also, the blowing process enables installation of the ribbed and grooved optical fiber cable <NUM> using pressurized air combined with a mechanical pushing force. Further, the ribbed and grooved optical fiber cable <NUM> includes the plurality of strength members <NUM>. Furthermore, each of the plurality of strength members <NUM> is embedded in the sheath <NUM>.

In an embodiment, each of the plurality of strength elements <NUM> in the sheath <NUM> may be positioned differently. Particularly, the plurality of strength members <NUM> enhances blowing performance of the ribbed and grooved optical fiber cable <NUM> by increasing stiffness of the ribbed and grooved optical fiber cable <NUM>. Moreover, the plurality of strength members <NUM> provides tensile strength to the ribbed and grooved optical fiber cable <NUM>. In an embodiment, the plurality of strength members <NUM> embedded in the sheath <NUM> of the ribbed and grooved optical fiber cable <NUM> is in the range of <NUM> to <NUM>. In another embodiment, the number of the plurality of strength members <NUM> may vary.

<FIG> illustrates the sheath having the plurality of ribs and the plurality of grooves on the external surface of the sheath and strength members embedded inside the sheath in accordance with a second configuration which lies outside the scope of the present invention. The plurality of ribs <NUM> in the sheath <NUM> is <NUM>. Alternatively, the plurality of ribs <NUM> in the sheath <NUM> may vary. In an embodiment the plurality of grooves <NUM> in the sheath <NUM> is <NUM>. Alternatively, the plurality of grooves <NUM> may vary. In an embodiment, the area of the ribbed and grooved optical fiber cable <NUM> corresponding to <NUM> ribs and <NUM> grooves is about <NUM> millimeter square. In particular, area of the cable may vary depending upon internal diameter of the cable, external diameter of the cable, number of the plurality of ribs <NUM> and the plurality of grooves <NUM>.

The ribbed and grooved optical fiber cable <NUM> has deformation of about <NUM> under crushing load at <NUM> Newton per <NUM> millimeter. Alternatively, deformation of the ribbed and grooved optical fiber cable <NUM> may vary. In addition, deformation of the ribbed and grooved optical fiber cable <NUM> may vary depending upon the plurality of parameters. The plurality of parameters includes but may not be limited to number of the plurality of ribs <NUM> and the plurality of grooves <NUM>, width and height of the plurality of ribs <NUM> and the plurality of grooves <NUM>, inside and outside diameter of the ribbed and grooved optical fiber cable <NUM>, number of the plurality of strength members <NUM> in the sheath <NUM>, and material grade of the ribbed and grooved optical fiber cable <NUM>.

In an embodiment, the plurality of ribs (i.e. the plurality of external ribs) <NUM> and the plurality of grooves (i.e. the plurality of external grooves) <NUM> are arranged alternately to each other on the outer surface of the sheath <NUM>. In an example, a groove of the plurality of grooves <NUM> is present on both sides of each rib of the plurality of ribs <NUM>. In another example, a rib of the plurality of ribs <NUM> is present on both sides of each groove of the plurality of grooves <NUM>. In an embodiment falling outside the scope of the present invention, height of each of the plurality of ribs <NUM> is equal. Alternatively, height of each of the plurality of grooves <NUM> is equal. In an embodiment, the plurality of ribs <NUM> and the plurality of grooves <NUM> may have any shape including but not limited to arc, rectangular, square, triangular, trapezoidal etc..

<FIG> illustrates the sheath of the cable with the plurality of ribs of different heights in accordance with an embodiment which lies outside the scope of the present invention. In particular, the plurality of ribs <NUM> includes a first type of ribs and a second type of ribs. Each rib of the first type of ribs has a large size. Each rib of the second type of ribs has a smaller size as compared to the first type of ribs. In an embodiment, height of the first type of ribs (i.e. a first height) is larger than height of the second type of ribs (i.e. a second height). In an example, during installation of the ribbed and grooved optical fiber cable <NUM> into a duct, only the first type of ribs touches the duct. In addition, the second type of ribs does not touch the duct due to the small size of the second type of ribs.

In an embodiment, the number of the first type of ribs is equal to the number of the second type of ribs. Particularly, the first type of ribs and the second type of ribs are arranged alternately to each other. The alternate arrangement of the first type of ribs and the second type of ribs reduces weight of the ribbed and grooved optical fiber cable <NUM>. Moreover, the alternate arrangement of the first type of ribs and the second type of ribs reduces friction in the ribbed and grooved optical fiber cable <NUM>. In an embodiment, the number of the first type of ribs is <NUM>. In another embodiment, the number of the first type of ribs may vary. In an embodiment, the number of the second type of ribs is <NUM>. In another embodiment, the number of the second type of ribs may vary. In an embodiment, the plurality of ribs <NUM> (first type of ribs and second type of ribs) is <NUM>. In another embodiment, the number of the plurality of ribs <NUM> may vary.

In an embodiment, the area of the ribbed and grooved optical fiber cable <NUM> corresponding to <NUM> ribs is about <NUM> millimeter square. Particularly, the area of the ribbed and grooved optical fiber cable <NUM> may vary depending upon internal diameter of the cable, external diameter of the cable, number of the plurality of ribs <NUM>.

In an embodiment, the ribbed and grooved optical fiber cable <NUM> has deformation of about <NUM> under crushing load at <NUM> Newton per <NUM> millimeter. In another embodiment, deformation of the ribbed and grooved optical fiber cable <NUM> may vary. In addition, deformation of the ribbed and grooved optical fiber cable <NUM> may vary depending upon the plurality of parameters. The plurality of parameters includes but may not be limited to number of the plurality of ribs <NUM> and the plurality of grooves <NUM>, width and height of the plurality of ribs <NUM> and the plurality of grooves <NUM>, inside and outside diameter of the ribbed and grooved optical fiber cable <NUM> , number of the plurality of strength members <NUM> in the sheath <NUM>, and material grade of the ribbed and grooved optical fiber cable <NUM>.

<FIG> illustrates the sheath of the cable having a plurality of internal grooves, a plurality of external grooves, a plurality of internal ribs and a plurality of external ribs in accordance with an embodiment lying outside the scope of the present invention. The sheath <NUM> has the plurality of ribs <NUM>, the plurality of grooves <NUM>, and the plurality of strength members <NUM>. The plurality of ribs <NUM> is formed on the outer surface of the sheath <NUM> and may be referred to as the plurality of external ribs. Further, the sheath <NUM> includes a plurality of internal ribs 104a and a plurality of internal grooves 106a formed on an internal surface of the sheath <NUM>.

In an implementation, the number of the plurality of ribs <NUM> on the outer surface of the sheath <NUM> of the ribbed and grooved optical fiber cable <NUM> is <NUM>. Alternatively, the number of the plurality of ribs <NUM> on the outer surface of the sheath <NUM> of the ribbed and grooved optical fiber cable <NUM> may vary.

Each of the plurality of ribs <NUM> has height of about <NUM> millimeter. Alternatively, height of the plurality of ribs <NUM> may vary. The sheath <NUM> includes the plurality of grooves <NUM>, and the plurality of grooves <NUM> is also called the plurality of external grooves. Further, the sheath <NUM> includes a plurality of internal grooves 106a formed on an inner/internal surface of the sheath <NUM>. The plurality of internal grooves 106a reduces the mass of the ribbed and grooved optical fiber cable <NUM>. In addition, the plurality of internal grooves 106a increases free space for optical fibers or ribbons in the ribbed and grooved optical fiber cable <NUM>. The plurality of external grooves <NUM> is formed on the outer surface of the sheath <NUM>.

In an implementation, the plurality of internal grooves 106a on the inner surface of the sheath <NUM> is <NUM>. Alternatively, the plurality of internal grooves 106a on the inner surface of the sheath <NUM> may vary. The plurality of internal grooves 106a has a depth of about <NUM> millimeter. Alternatively, the depth of the plurality of internal grooves 106a may vary. In an implementation, the plurality of external grooves <NUM> on the outer surface of the sheath <NUM> is <NUM>. Alternatively, the plurality of external grooves <NUM> on the outer of the sheath <NUM> may vary. Further, the area of the ribbed and grooved optical fiber cable <NUM> corresponding to <NUM> external ribs and <NUM> internal grooves is about <NUM> millimeter square. Alternatively, area of the cable may vary depending upon internal diameter of the cable, external diameter of the cable, number of the plurality of ribs <NUM>. The ribbed and grooved optical fiber cable <NUM> has deformation of about <NUM> millimeter under crushing load at <NUM> Newton per <NUM> millimeter. Alternatively, deformation of the ribbed and grooved optical fiber cable <NUM> may vary. In addition, deformation of the ribbed and grooved optical fiber cable <NUM> may vary depending upon the plurality of parameters. The plurality of parameters includes but may not be limited to number of the plurality of ribs <NUM> and number of the plurality of internal grooves 106a and the plurality of external grooves <NUM>, width and height of the plurality of ribs <NUM> and the plurality of grooves <NUM>, inside and outside diameter of the ribbed and grooved optical fiber cable <NUM> , number of the plurality of strength members <NUM> in the sheath <NUM>, and material grade of the ribbed and grooved optical fiber cable <NUM>.

<FIG> illustrates the sheath of the cable having embedded strength members. In particular, the plurality of ribs <NUM> includes a first type of ribs and a second type of ribs. Each rib of the first type of ribs has a large size. Each rib of the second type of ribs has a smaller size as compared to the first type of ribs. Further, height of the first type of ribs (i.e. the first height) is larger than height of the second type of ribs (i.e. the second height).

In an implementation, the number of the first type of ribs is equal to the number of the second type of ribs. The first type of ribs and the second type of ribs are arranged alternately to each other. The alternate arrangement of the first type of ribs and the second type of ribs reduce weight of the ribbed and grooved optical fiber cable <NUM>. In particular, the alternate arrangement of the first type of ribs and the second type of ribs reduces friction in the ribbed and grooved optical fiber cable <NUM>. In an example, the number of the first type of ribs is <NUM>. Alternatively, the number of the first type of ribs may vary. Further, the number of the second type of ribs is <NUM>. Alternatively, the number of the second type of ribs may vary.

In an embodiment, the plurality of ribs <NUM> (first type of ribs and second type of ribs) is <NUM>. Alternatively, the plurality of ribs <NUM> may vary. Further, the plurality of grooves <NUM> in the ribbed and grooved optical fiber cable <NUM> is <NUM>. Alternatively, the plurality of grooves <NUM> may vary. In an embodiment, the area of the ribbed and grooved optical fiber cable <NUM> corresponding to <NUM> ribs is about <NUM> millimeter square. Alternatively, area of the ribbed and grooved optical fiber cable <NUM> may vary depending upon internal diameter of the cable, external diameter of the cable, number of the plurality of ribs <NUM>. The ribbed and grooved optical fiber cable <NUM> has deformation of about <NUM> millimeter under crushing load at <NUM> Newton per <NUM> millimeter. Alternatively, deformation of the ribbed and grooved optical fiber cable <NUM> may vary.

In particular, deformation of the ribbed and grooved optical fiber cable <NUM> may vary depending upon the plurality of parameters. The plurality of parameters includes but may not be limited to number of the plurality of ribs <NUM> and number of internal grooves of the plurality of grooves <NUM>, width and height of the plurality of ribs <NUM> and the plurality of grooves <NUM>, inside and outside diameter of the ribbed and grooved optical fiber cable <NUM>, number of the plurality of strength members <NUM> in the sheath <NUM>, and material grade of the ribbed and grooved optical fiber cable <NUM>.

The plurality of ribs <NUM> and the plurality of grooves <NUM> of the ribbed and grooved optical fiber cable <NUM> (of <FIG>) are arranged alternately to each other on the outer surface of the sheath <NUM>. In an example, height of the first type of ribs of the ribbed and grooved optical fiber cable <NUM> i.e. the first height is <NUM> millimeter. In particular, the height of the second type of ribs of the ribbed and grooved optical fiber cable <NUM> i.e. the second height is <NUM> millimeter. In another example, height of the first type of ribs (i.e. the first height) of the ribbed and grooved optical fiber cable <NUM> may vary. In addition, height of the second type of ribs (i.e. the second height) of the ribbed and grooved optical fiber cable <NUM> may vary.

The alternate arrangement of the first type of ribs and the second type of ribs enables high crushing performance. In addition, the first type of ribs support the second type of ribs when a fixed crush load is applied on the ribbed and grooved optical fiber cable <NUM> that enables high crushing performance as compared to the similar design of cable where all the ribs have equal height. Further, the number of the first type of ribs and the second type of ribs is an odd number. Furthermore, the odd number of the first type of ribs and the second type of ribs ensures that each of the first type of ribs is diametrically opposite to the corresponding rib of the second type of ribs. Moreover, the odd number of the first type of ribs and the second type of ribs eliminates dependency on orientation of the fixed crush load on the ribbed and grooved optical fiber cable <NUM>. In an example, the sheath <NUM> having more number of the first type of ribs (large sized ribs) has small lateral deformations. Adjacent ribs provide support to the cross section of the ribbed and grooved optical fiber cable <NUM> when the cable starts to deform and take an elliptical shape. In another example, the sheath <NUM> has less plurality of ribs <NUM>. The plurality of ribs <NUM> are more spaced out in the sheath <NUM> due to less number of plurality of ribs <NUM>. In addition, the sheath <NUM> with less plurality of ribs <NUM> does not provide support to the cross section of the ribbed and grooved optical fiber cable <NUM> even at low forces.

<FIG> illustrates the sheath of the cable having the plurality of grooves and the plurality of ribs extruded in a linear manner along a length of the cable in accordance with an embodiment outside the scope of the present invention. Particularly, the plurality of ribs <NUM> and the plurality of grooves <NUM> are extruded longitudinally along the length of the ribbed and grooved optical fiber cable <NUM>.

<FIG> illustrates the sheath of the cable having the plurality of grooves and the plurality of ribs extruded helically along the length of the cable in accordance with an embodiment lying outside the scope of the present invention. Particularly, the plurality of ribs <NUM> and the plurality of grooves <NUM> are extruded helically along the length of the ribbed and grooved optical fiber cable <NUM>. Alternatively, the plurality of ribs <NUM> and the plurality of grooves <NUM> are extruded in SZ fashion. Alternatively, the plurality of ribs <NUM> and the plurality of grooves <NUM> may be extruded in any suitable shape.

<FIG> illustrates the sheath of the cable having the plurality of internal grooves, the plurality of external grooves, the plurality of internal ribs and the plurality of external ribs in accordance with an embodiment of the present invention. The sheath <NUM> includes the plurality of ribs <NUM> on the external surface of the sheath (referred to as the plurality of external ribs <NUM> with reference to <FIG>), the plurality of grooves <NUM> on the external surface of the sheath (referred to as the plurality of external grooves <NUM> with reference to <FIG>), the plurality of internal ribs 104a, the plurality of internal grooves 106a and the plurality of strength members <NUM>. The plurality of ribs <NUM> includes the first type of ribs and the second type of ribs. Each rib of the first type of ribs has a large size. Each rib of the second type of ribs has a smaller size as compared to the first type of ribs. Further, the height of each of the first type of ribs (i.e. the first height) is larger than the height of each of the second type of ribs (i.e. the second height). Further, the number of the first type of ribs is equal to the number of the second type of ribs. The first type of ribs and the second type of ribs are arranged alternately to each other. The alternate arrangement of the first type of ribs and the second type of ribs reduces weight of the ribbed and grooved optical fiber cable <NUM>. In addition, the alternate arrangement of the first type of ribs and the second type of ribs reduces friction in the ribbed and grooved optical fiber cable <NUM>. Further, the number of the first type of ribs is <NUM>. Alternatively, the number of the first type of ribs may vary. Furthermore, the number of the second type of ribs is <NUM>. Alternatively, the number of the second type of ribs may vary. In an implementation, the plurality of ribs <NUM> (first type of ribs and second type of ribs) is <NUM>. Alternatively, the plurality of ribs <NUM> may vary. The ribbed and grooved optical fiber cable <NUM> includes the plurality of external grooves <NUM>. In addition, the plurality of grooves 106a corresponds to the internal grooves. The plurality of ribs <NUM> surrounds the plurality of grooves <NUM>. The plurality of grooves 106a (the internal grooves) are formed on the inner surface of the sheath <NUM>. Further, the number of the internal grooves on the inner surface of the sheath <NUM> is <NUM>. Alternatively, the number of the internal grooves on the inner surface of the sheath <NUM> may vary.

In the sheath with the ribs of different heights, the outer diameter upto <NUM> and a sheath thickness upto <NUM>, the first height may be in a range of <NUM>-<NUM> millimeter (mm) and the second height may be in the range of <NUM>-<NUM> millimeter. Preferably, the first height may be in the range of <NUM>-<NUM> millimeter and the second height may be in the range of <NUM>-<NUM> millimeter. Below the first height of <NUM>, the ribs will be difficult to manufacture and above the first height of <NUM>, the sheath may become mechanically weak. Further, the plurality of ribs <NUM> may have a width in the range of <NUM>-<NUM> millimeter. Below the width of <NUM>, the ribs will be mechanically weak and beyond the width of <NUM>, the blowing performance will be affected. Furthermore, the plurality of grooves <NUM> may have a width in the range of <NUM>-<NUM> millimeter. The alternate arrangement of the first type of ribs and the second type of ribs enables high crushing performance. The first type of ribs support the second type of ribs when a fixed crush load is applied on the ribbed and grooved optical fiber cable <NUM> that enables high crushing performance as compared to the similar design of cable where all the ribs have equal height. In an implementation, the number of the first type of ribs and the second type of ribs is an odd number. The odd number of the first type of ribs and the second type of ribs ensures that each of the first type of ribs is diametrically opposite to the corresponding rib of the second type of ribs. Moreover, the odd number of the first type of ribs and the second type of ribs eliminates dependency on orientation of the fixed crush load on the ribbed and grooved optical fiber cable <NUM>.

<FIG> illustrates the strength member of the cable coated with a coating material in accordance with an embodiment lying outside the scope of the present invention. The plurality of strength members <NUM> embedded in the sheath <NUM> may have a circular shape or any other suitable shape. The one or more strength members <NUM> are coated with the coating material having at least one of an ultraviolet (UV) curable water swellable resin composition (or resin) and a thick layer of ethylene acrylic acid (EAA) to prevent water ingression in the ribbed and grooved optical fiber cable <NUM> as without the coating material, the water may seep through the one or more strength members <NUM> embedded in the sheath <NUM>.

During the coating process, the thick layer of ethylene acrylic acid (EAA) <NUM> may be coated on the one or more strength members <NUM> before embedding in the sheath <NUM>. The ethylene acrylic acid (EAA) provides a good adhesion between the one or more strength members <NUM> and the sheath <NUM> to further prevent from water ingression.

Alternatively, the UV curable water swellable resin composition <NUM> is coated on the one or more strength members <NUM> and cured before embedding in the sheath <NUM>. In case, the resin composition comes in contact with water, it swells and blocks the way for water to avoid penetration in the core of the ribbed and grooved optical fiber cable <NUM>. Typically, the core includes the plurality of optical fibers. The plurality of optical fibers may be incorporated in the core as a plurality of loose tube optical fibers, a plurality of tight buffered optical fibers, a group or stack of optical fiber ribbons or the like. , which is enclosed by the sheath <NUM>. The UV curable water swellable resin composition can include, but not limited to, acrylic acid, phenyl bis(<NUM>,<NUM>,<NUM>-trimethylbenzoyl)-phosphine oxide and oxybis(methyl-<NUM>,<NUM>-ethanediyl) diacrylate. In an implementation, the UV curable water swellable resin composition may be applied directly on the one or more strength members <NUM> or above a thin layer of ethylene acrylic acid (EAA) having a thickness of <NUM> ± <NUM> microns. The thin layer of ethylene acrylic acid (EAA) helps to achieve better adhesion of the one or more strength members with material of the sheath. Once, the UV curable water swellable resin composition is applied on the one or more strength members <NUM>, the one or more strength members <NUM> are passed through one or more UV chambers to cure the UV curable water swellable resin composition.

The coating <NUM> may have a thickness, preferably, in a range of <NUM> microns to <NUM> microns as a thinner layer of the coating material may lead to water ingression. Also, a sheathing tool has strength member embedding holes that supports the coating thickness upto <NUM>-<NUM> microns. Beyond this, abrasion will occur and will further lead to waste creation. Alternatively, the thickness of the coating may vary. Further, the one or more strength members <NUM> may be made of fiber reinforced plastic (FRP), aramid reinforced plastic (ARP) or any other suitable material.

<FIG> illustrates the sheath of the cable in accordance with the present invention.

The sheath <NUM> has the plurality of ribs <NUM>, the plurality of grooves <NUM> and the plurality of strength members <NUM>. The sheath <NUM> encloses the plurality of optical fibers. The plurality of grooves <NUM> on the outer surface of the sheath <NUM> may be called as the plurality of external grooves or external grooves. The plurality of grooves <NUM> on the inner surface of the sheath <NUM> may be called as the plurality of internal grooves or internal grooves. Similarly, the plurality of ribs <NUM> on the outer surface of the sheath <NUM> may be called as the plurality of external ribs or external ribs. The plurality of ribs 104a on the inner surface of the sheath <NUM> may be called as the plurality of internal ribs or internal ribs.

The plurality of ribs <NUM> includes a first type of ribs and a second type of ribs. Each rib of the first type of ribs may have a larger size than each rib of the second type of ribs. Alternatively, each rib of the first type of ribs may have smaller size than each rib of the second type of ribs. The ribbed and grooved optical fiber cable <NUM> having the plurality of ribs <NUM> may have at least two heights. The first type of ribs may have the first height and the second type of ribs may have the second height. The first type of ribs may have a larger height than of the second type of ribs. Alternatively, the first type of ribs may have smaller height than of the second type of ribs. The plurality of ribs <NUM> and the plurality of grooves <NUM> of the ribbed and grooved optical fiber cable <NUM> are arranged alternately to each other on the outer surface of the sheath <NUM>. The height (i.e. the first height) of the first type of ribs and the height (i.e. the second height) of the second type of ribs of the ribbed and grooved optical fiber cable <NUM> may vary. Further, height of each of the plurality of grooves <NUM> is equal. Alternatively, height of each of the plurality of grooves <NUM> may vary. In an example, the sheath <NUM> having more number of the first type of ribs (large sized ribs) has small lateral deformations. Adjacent ribs provide support to the cross section of the ribbed and grooved optical fiber cable <NUM> when the cable starts to deform and take an elliptical shape. In another example, the sheath <NUM> has less plurality of ribs <NUM>. The plurality of ribs <NUM> are more spaced out in the sheath <NUM> due to less number of plurality of ribs <NUM>. In addition, the sheath <NUM> with less plurality of ribs <NUM> does not provide support to the cross section of the ribbed and grooved optical fiber cable <NUM> even at low forces.

<FIG> illustrates a water penetration test arrangement for the cable in accordance with an embodiment lying outside the scope of the present invention. Once the plurality of strength members <NUM> are embedded in the sheath <NUM>, the ribbed and grooved optical fiber cable <NUM> may pass water penetration test. In the water penetration test, <NUM> bar pressure water-head was applied to a <NUM> cable sample kept for at least <NUM> hours.

In another test, the sample was pre-soaked in a bucket of water to a depth of <NUM> ± <NUM> for <NUM> before the test. In yet another test, the cable sample <NUM> of <NUM> meters was taken and a watertight seal <NUM> was applied to allow a <NUM> (H) of water-head <NUM> to be applied for <NUM> hours.

Referring to <FIG>, the sheath <NUM> and the plurality of external ribs <NUM> may be made of same material such as polyvinyl chloride, polyethylene (such as High Density Polyethylene (HDPE), Medium Density Polyethylene, and Low Density Polyethylene), polyurethane, thermoplastic rubber/elastomer, thermoplastic chlorinated polyethylene, thermoset polyolefins or combination thereof.

Alternatively, the sheath <NUM> and the plurality of external ribs <NUM> may be made of different materials. The plurality of external ribs <NUM> and the plurality of external grooves <NUM> are one or more of a rectangular shape with rounded edges, a pointy triangle shape, a circular shape, a curve-type shape or other suitable shape. Further, the plurality of external ribs <NUM> has a height (first height or second height or both) in a range of <NUM>-<NUM> millimeters, the plurality of external ribs <NUM> has a width in a range of <NUM>-<NUM> millimeters and the plurality of external grooves <NUM> has a width in a range of <NUM>-<NUM> millimeters. Furthermore, the optical fiber ribbed and grooved optical fiber cable <NUM> has a diameter in a range of <NUM> to <NUM> millimeters, and the optical fiber cable has a blowing of more than <NUM> meters in the duct with an inner diameter of <NUM> millimeters and an outer diameter of <NUM> millimeters. The plurality of internal ribs have the height in the range of <NUM>-<NUM> millimeter and the width in the range of <NUM>-<NUM> millimeters. Further, the plurality of internal grooves have the width in the range of <NUM>-<NUM> millimeters. The ribbed and grooved cable that reduces coefficient of friction between a cable sheath and a duct. Moreover, the ribbed and grooved cable has embedded strength member(s) in the cable sheath with a water blocking coating to provide mechanical strength and ease of blowing to the ribbed and grooved cable and to prevent water ingression inside the ribbed and grooved cable. Further, the inner grooves reduce mass of the ribbed and grooved cable while increasing free space for optical fibers or ribbons in the ribbed and grooved cable.

Overall, the present disclosure provides advantages such as a high blowing performance, reduced mass of the cable, increased free space for optical fibers or ribbons in the cable, large and irregular surface area, increased drag force, reduced coefficient of friction between the sheath and the duct, and better crushing behaviour.

A person of ordinary skill in the art may be aware that, in combination with the examples described in the embodiments disclosed in this specification, units and algorithm steps may be implemented by electronic hardware, computer software, or a combination thereof. The disclosure should not be limited by the above described embodiment, method, and examples, but by all embodiments and methods within the scope of the attached claims. It is intended that the specification and examples be considered as exemplary, with the true scope of the disclosure being indicated by the claims.

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 embodiments require at least one of X, at least one of Y, or at least one of Z to each be present.

The foregoing descriptions are merely specific implementations of the present disclosure, but are not intended to limit the protection scope of the present disclosure.

Claim 1:
A ribbed and grooved fiber cable (<NUM>) comprising:
a core with a plurality of optical fibers;
a sheath (<NUM>) enveloping the core,
wherein the sheath (<NUM>) has an outer surface and an inner surface, wherein the outer surface of the sheath (<NUM>) has a plurality of external ribs (<NUM>) and a plurality of external grooves (<NUM>); and
at least one of one or more strength members (<NUM>) embedded in the sheath (<NUM>), a plurality of ribs (<NUM>) and grooves (<NUM>) on an external surface of the sheath (<NUM>), and a plurality of ribs (104a) and grooves (106a) on an internal surface of the sheath (<NUM>), wherein the plurality of ribs (<NUM>) have variable height, wherein the one or more strength members (<NUM>) are coated with a water blocking coating material having at least one of an ultraviolet (UV) curable water swellable resin composition and a layer of ethylene acrylic acid (EAA).