WO2022153127A1

WO2022153127A1 - Sealing unit for sealing an optical fiber cable

Info

Publication number: WO2022153127A1
Application number: PCT/IB2022/000015
Authority: WO
Inventors: Eric Schurmans; Kristof Vastmans; Jiri ZAVREL
Original assignee: CommScope Connectivity Belgium BV
Priority date: 2021-01-15
Filing date: 2022-01-14
Publication date: 2022-07-21

Abstract

A cable sealing unit for environmentally sealing a fiber optic cable. The cable sealing unit including an outer shell and an elastomeric sealant material which is molded within the outer shell. The outer shell including cable pass through locations and the elastomeric sealing material including cable sealing locations, each including a first annular rib defining a first inner diameter, a second annular sealing rib defining a second inner diameter and a third annular sealing rib defining a third inner diameter. The first inner diameter is larger than the second diameter and the second inner diameter is larger than the third inner diameter.

Description

SEALING UNIT FOR SEALING AN OPTICAL FIBER CABLE

CROSS-REFERENCE TO RELATED APPLICATION

This application is being filed on January 14, 2022 as a PCT International Patent Application and claims the benefit of U.S. Patent Application Serial No. 63/137,856, filed on January 15, 2021, the disclosure of which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates generally to cable sealing units for optical fiber cables.

BACKGROUND

Fiber optic telecommunications technology is becoming more prevalent as service providers strive to deliver higher bandwidth communication capabilities to customers/subscribers. As data transmissions increase, the fiber optic network is being extended closer to the end user which can be a premise, business, or a private residence.

As telecommunication cables are routed across data networks, it is necessary to periodically open the cable so that one or more telecommunication lines therein may be spliced, thereby allowing data to be distributed to other cables or "branches" of the telecommunication network. At each point where a telecommunication cable is opened, it is necessary to provide a telecommunications enclosure to protect the exposed interior of the cable. The cable branches may be further distributed until the network reaches individual homes, businesses, offices, and so on. These networks are often referred to as fiber to the premise (FTTP) or fiber to the home (FTTH) networks. In an FTTH network, fiber optic cable is run from the service provider's central office to an ONT located at the subscriber's residence or office space.

Figures 1 and 2 illustrate a portion of a fiber optic network 10. A telecommunications cable 12 (e.g., a single fiber or multi-fiber distribution cable) is shown passing through an example optical terminal enclosure or OTE 14. The telecommunications cable 12 includes optical fibers 22, typically there are twelve to forty-eight optical fibers 22 within the cable 12, however, larger numbers of fibers 22 can be employed. The fibers 22 of the cable 12 are protected within an outer jacket 16. An incision 18 (e.g., cut) can be made in the outer jacket 16 of the cable 12 such that a portion of the outer jacket 16 can be removed from the cable 12 that is outside the OTE 14 to provide a window 20 that exposes the optical fibers 22. One or more of the optical fibers 22 of the telecommunications cable 12 may be cut at a location 24 aligned with the window 20.

The cut optical fibers 22a (see Figure 2) may be retracted out of the cable 12 while the remaining optical fibers 22 are uncut and continue to pass through. For example, a second incision can be made in the outer jacket 16 such that a portion of the outer jacket 16 may be removed to provide a second window 19. The cut optical fiber 22a can be retracted out of the cable through the second window 19. The OTE 14 is mounted over the second window 19. The cut optical fibers 22a are retracted out of the cable 12 and are protected and managed within the OTE 14.

A sealing arrangement 32 is mounted over the first window 18 to environmentally seal the telecommunications cable. The distance between the OTE 14 and the sealing arrangement 32 can be from about 2 meters up to about 100 meters. The distance can vary with the length of the telecommunications cable 12 and the required distance to be routed. The distance can also depend on whether the path of travel is a straight line or a path with many turns. The location of the incision or cut will also be a factor in addition to the friction of the cable 12. The PCT publication WO 2019/197665 shows one such example of a sealing arrangement.

Improvements in telecommunications enclosures to protect the exposed interior of fiber optic cables are desirable

SUMMARY

Features of the present disclosure relate to a cable sealing unit for use over an incision on a fiber optic cable. The cable sealing unit includes an outer shell. The outer shell has first and second opposite ends. The first and second opposite ends are separated by a length of the outer shell. The outer shell defines a central longitudinal axis that extends along the length of the outer shell. The outer shell defines cable pass-through locations at each of the first and second ends of the outer shell. The outer shell includes first and second shell pieces that each extend along the length of the shell. The first and second shell pieces meet at a longitudinal first seam defined between first edges of the first and second shell pieces that extend along the length of the outer shell. The first and second shell pieces also meet at a longitudinal second seam defined between second edges of the first and second shell pieces that extend along the length of the outer shell. The first and second longitudinal seams are positioned on opposite sides of the longitudinal axis.

The cable sealing unit additionally includes an elastomeric sealant material. The elastomeric sealant material is molded within the outer shell. The elastomeric sealant material is softer than the outer shell. The elastomeric sealant material includes a first sealant portion carried with the first shell piece and a second sealant portion carried with the second shell piece. The elastomeric sealing material provides sealing between the first and second shell pieces along the first and second edges and provides cable sealing locations at the cable pass-through locations. The cable sealing locations each include a first annular sealing rib which defines a first inner diameter, a second annular sealing rib which defines a second inner diameter and a third annular sealing rib which defines a third inner diameter. The first inner diameter is larger than the second inner diameter and the second inner diameter is larger than the third inner diameter. The first, second and third annular sealing ribs are axially spaced from one another along the central longitudinal axis.

A variety of additional aspects will be set forth in the description that follows. The aspects can relate to individual features and to combinations of features. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the broad inventive concepts upon which the embodiments disclosed herein are based.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic representation of a fiber optic network including a cable passing through an optical termination enclosure, the cable having an incision in accordance with the principles of the present disclosure;

Figure 2 is the schematic representation shown in Figure 1 with an optical fiber retracted from the cable and an enclosure arrangement positioned over the incision in accordance with the principles of the present disclosure;

Figure 3 is a view of an example cable sealing unit to seal an incision including a first and a second shell piece in accordance with the principles of this disclosure;

Figure 3 A is an exploded view of the cable sealing unit of Figure 3;

Figure 4 is a front view of the first shell piece of the cable sealing unit of Figure 3; Figure 5 is a rear view of the first shell piece of Figure 3;

Figure 6 is a front view of the second shell piece of Figure 3;

Figure 7 is a rear view of the second shell piece of Figure 3;

Figure 8 is a front view of sealing material used in the cable sealing unit of Figure 3; and

Figure 9 is a rear view of the sealing material of Figure 8.

DETAILED DESCRIPTION

Reference will now be made in detail to exemplary aspects of the present disclosure that are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

The present disclosure relates to sealing arrangements for fiber optic cables. As discussed in the Background, when an incision is made in a fiber optic cable to allow for optical fibers to be cut, the cable must be re sealed at the location of the incision. The present disclosure relates to improvements in sealing arrangements such as the sealing arrangement 32 shown schematically in Figure 2 to environmentally seal the cable 12 where the incision 18 was made for allowing the optical fibers 22 to be cut (e.g., a fiber access location).

Referring to Figure 3, a cable sealing unit 40 in accordance with the principles of this disclosure is shown. The cable sealing unit 40 includes an outer shell 42 having a first end 44 and a second opposite end 46 separated by a length L of the outer shell 42. In one example, the first and second ends 44, 46 are each dome shaped. The outer shell defines a central longitudinal axis 15 that extends along the length L of the outer shell 42. The outer shell 42 additionally includes cable pass-through locations 48 at the first and the second ends 44, 46. In one example, the cable pass-through locations are defined in part by circular openings defined by the first and second ends 44, 46. In one example, the circular openings are centered (e.g., co-axial) with respect to the central longitudinal axis 15.

In a preferred example, the cable sealing unit is IP68 certified (e.g., Ingress Protection Code 68, Ingress Protection is a classification and rating of the degree of protection provided by mechanical casings and electrical enclosures against intrusion, dust, accidental contact and water). IP68 means that the cable sealing unit 40 is deemed fit to withstand dust, dirt and sand. Additionally, the cable sealing unit 40 can resist 1.5m of fresh water for up to 30 minutes. Referring to Figure 3A, an exploded view of the cable sealing unit 40 is shown. The outer shell 42 of the cable sealing unit 40 includes a first and a second shell piece 42a, 42b. The first and the second shell piece 42a, 42b meet at a longitudinal first seam defined between first edges 43a, 43b (see Figures 3, 4 and 6) of the first and second shell pieces 42a, 42b. The first edges 43a, 43b extend along the length L of the outer shell 42. The first and second shell pieces 42a, 42b additionally meet at a longitudinal second seam which is defined between second edges 45a, 45b (see Figures 3, 4 and 6) of the first and second shell pieces 42a, 42b. The first and second longitudinal seams are positioned on opposite sides of the longitudinal axis 15. A cable 12 is shown extending along the longitudinal axis 15.

The cable sealing unit 40 additionally includes an elastomeric sealant material 50 which is molded within the outer shell 42 in a two-step molding process where the first and second shell pieces 42a, 42b are first molded a first step and the elastomeric sealing material 50 is molded into the first and second shell pieces 42a, 42b in a second molding step. The elastomeric sealant material 50 is softer than the outer shell and includes a first sealant portion 50a, and a second sealant portion 50b. The first sealant portion 50a is carried within the first shell piece 42a and the second sealant portion 50b is carried within the second shell piece 42b. The elastomeric sealing material provides sealing between the first and second shell pieces 42a, 42b at the seams along the first and the second edges 43a, 43b, 45a, 45b.

The elastomeric sealing material additionally provides cable sealing locations 52 at the cable pass-through locations. The cable sealing locations 52 each include a first annular sealing rib 54a defining a first inner diameter, a second annular sealing rib defining a second inner diameter and a third annular sealing rib 54c defining a third inner diameter. The first inner diameter is larger than the second inner diameter and the second inner diameter is larger than the third inner diameter. The first, second and third annular sealing ribs 54a, 54b, 54c are axially spaced from one another along the central longitudinal axis 15. The sealant portions 50a, 50b cooperate to define the annular ribs 54a-54c (e.g., half of each rib is provided by each sealant portion 50a, 50b).

Referring to Figures 4 through 7 the first and second shell pieces 42a, 42b are shown in isolation. The first and second shell pieces 42a, 42b each include internal axial end containment walls 60 adjacent to the cable pass-through locations 48 for axially containing the elastomeric sealant within a first interior region 62. The internal axial containment walls 60 are transversely oriented relative to the central longitudinal axis 15. The internal axial containment walls 60 are axially inwardly offset from the first and second ends 44, 46 of the outer shell 42. The first and second pieces 42a, 42b of the outer shell 42 define second interior regions 64 between the internal axial end containment walls and the first and second ends 44, 46 of the outer shell 42. The second interior regions 64 are devoid of the elastomeric sealant material 50.

Additionally, the first and second pieces 42a, 42b of the shell include internal longitudinal ribs 66. The internal longitudinal ribs 66 embed within the sealant material 50 to assist securing the sealant material 50 to the first and second shell pieces 42a, 42b. The first and second shell pieces 42a, 42b each also include internal longitudinal containment walls 68. The internal longitudinal containment walls 68 prevent the sealant material 50 from filling a central section 62a of the second interior region 62 of the outer shell 42 while the sealant material 50 is molded within the shell.

The first and second pieces 42a, 42b include side ports 70. The side ports 70 are in fluid communication with outer cavities 72. The sealant material 50 flows through the side ports 70 and into the outer cavities 72 during the molding of the sealant material 50 and assists in providing retention of the sealant material 50 with respect to the first and second shell pieces 42a, 42b upon curing of the sealant material 50. In some examples, there is a degree of chemical bonding between the outer shell 42 and the sealant material 50.

The outer shell 42 includes a unitary hinge 74 between the first and the second shell pieces 42a, 42b at the first longitudinal seam 43a of the outer shell 42. The first shell piece 42a includes a hinge cylinder 74a. The second shell piece 42b includes a hinge receiver 74b which receives the hinge cylinder 74a. The first and second shell pieces 42a, 42b additionally include snaps 76 along the second longitudinal seam 43b. The snaps 76 allow for a snap fit connection at an interface between the first and the second shell pieces 42a, 42b where the snaps 76 meet at the second longitudinal seem 43b. Each of the first and second shell pieces 42a, 42b includes snaps 76a and snap receivers 76b. The snaps and snap receivers are positioned towards opposite ends on the first and second shell pieces 42a, 42b. For example, if the snaps 76a are towards the first end 42 on one of the shell pieces, the snap receivers would be towards the first end 42 on the other shell piece.

Referring to Figures 8 and 9 the elastomeric sealing portions 50a, 50b are shown in isolation. The first and second sealing portions 50a, 50b are similar to one another so one elastomeric sealing portion 50a, 50b is shown. In one example, the elastomeric sealing portions 50a, 50b have a Shore A hardness in the range of 8-15 and can have a material composition that includes rubber.

The elastomeric sealing portions 50a, 50b include a central sealing area 58 (i.e., a central region). The central sealing area 58 is the location which optical fibers 22 can be sealed within and is devoid of any elastomeric material. The central sealing area 58 is defined by areas where the elastomeric material has been molded around the internal longitudinal containment walls 68 and where the central section 62a is located. The elastomeric sealing portions 50a, 50b include indented portion where the internal longitudinal ribs 66 have made an impression during the molding process. The indented portion 66a additionally help with mechanically holding the elastomeric sealing portions 50a, 50b in place.

The internal annular sealing ribs 54a, 54b, 54c of the sealing portions 50a, 50b are easily seen at Figure 8. In some examples, the inner diameter of the first annular sealing rib 54a is at least 5, 10 or 15 percent larger than the inner diameter of the second annular sealing rib 54b and the second annular sealing rib 54b is at least 5, 10 or 15 percent larger than the inner diameter of the third annular sealing rib 54c. The different sizes of the annular sealing ribs 54a, 54b, 54c allow for cables of different sizes to be sealed within and accommodated by the cable sealing unit 40. The cable sealing unit 40 can accommodate cables with different diameters (e.g., cable having diameters ranging from 3-5 millimeters such as 3 millimeter diameter cables, 4 millimeter diameter cables and 5 millimeter diameter cables) or can accommodate different cable sizes across a diameter range of at least 2, 3, 4, or 5 millimeters. It is within the scope of this disclosure that the sizes of the annular sealing ribs 54a, 54b, 54c can be altered to accommodate larger cables, in this case the annular sealing ribs 54a, 54b, 54c would be smaller, or smaller cables, in this case the annular sealing ribs 54a, 54b, 54c would be smaller.

The second sealing rib 54b is shown axially between the first and the third sealing ribs 54a, 54c. The first sealing rib 54a is shown offset from the second sealing rib 54b in an axially outward direction away from the central sealing area 58. The third sealing rib 54c is offset from the second sealing rib 54b in a direction axially inwards towards the central sealing area 58.

The elastomeric sealing portions 50a, 50b includes longitudinal seam sealing portions 56. The longitudinal seam sealing portions 56 extend along the length L of the shell between the internal containment walls and the first and second edges 43a, 43b, 45a, 45b of the shell pieces 42a, 42b, thus providing a seal between the first and second edges 43a, 43b, 45a, 45b of the shell pieces 42a, 42b.

The elastomeric sealing portions 50a, 50b include portions 72a which are portions where the elastomeric sealing material has flowed through the ports 70 and molded within the cavities 72. The portions 72a assist in holding the sealing portions 50a, 50b in place mechanically. The portions 72a can be referred to as outer cavity portions or sealing material retention portions. Main portions of the sealing portions 50a, 50b are molded inside the shell 42 and the portions 72a are located in the outer cavities at the outside of the shell 42. Sealing material within the ports 72 connects the main portions of the sealing portions 50a, 50b to the outer cavity portions 72a.

From the forgoing detailed description, it will be evident that modifications and variations can be made without departing from the spirit and scope of the disclosure.

Claims

9 CLAIMS:

1. A cable sealing unit comprising: an outer shell having first and second opposite ends separated by a length of the outer shell, the outer shell defining a central longitudinal axis that extends along the length of the shell, the outer shell defining cable pass-through locations at each of the first and second ends of the shell, the shell including first and second shell pieces that each extend along the length of the shell, the first and second shell pieces meeting at a longitudinal first seam defined between first edges of the first and second shell pieces that extend along the length of the outer shell, the first and second shell pieces meeting at a longitudinal second seam defined between second edges of the first and second shell pieces that extend along the length of the outer shell, the first and second longitudinal seams being positioned on opposite sides of the longitudinal axis; and an elastomeric sealant material molded within the outer shell, the elastomeric sealant material being softer than the outer shell, the elastomeric sealant material including a first sealant portion carried with the first shell piece and a second sealant portion carried with the second shell piece, the elastomeric sealing material providing sealing between the first and second shell pieces along the first and second edges and providing cable sealing locations at the cable pass-through locations, the cable sealing locations each including a first annular sealing rib defining a first inner diameter, a second annular sealing rib defining a second inner diameter and a third annular sealing rib defining a third inner diameter, wherein the first inner diameter is larger than the second inner diameter and the second inner diameter is larger than the third inner diameter, and wherein the first, second and third annular sealing ribs are axially spaced from one another along the central longitudinal axis.

2. The cable sealing unit of claim 1, wherein the first inner diameter is at least 5, 10 or 15 percent larger than the second inner diameter and the second inner diameter is at least 5, 10 or 15 percent larger than the third inner diameter.

3. The cable sealing unit of claim 1, wherein the second sealing rib is axially between the first and third sealing ribs, wherein the first sealing rib is offset from the second sealing rib in an axially outward direction and the third sealing rib is offset from the second sealing rib in an axially inward direction.

4. The cable sealing unit of claim 1, wherein the elastomeric sealant has a Shore A hardness in the range of 8-15.

5. The cable sealing unit of claim 1, wherein the shell includes internal axial end containment walls adjacent the cable pass-through locations for axially containing the sealant within a first interior region of the shell, the internal axial containment walls being transversely oriented relative to the central longitudinal axis.

6. The cable sealing unit of claim 5, wherein the internal axial end containment walls are axially inwardly offset from the first and second ends of the shell, wherein the shell defines second interior regions between the internal axial end containment walls and the first and second ends of the shell, and wherein the second interior regions are devoid of the sealant material.

7. The cable sealing unit of claim 6, wherein the shell includes dome-shaped end portions that enclose the second interior regions and define the first and second ends of the shell, the dome-shaped end portions defining circular cable pass-through openings at the first and second ends of the shell that are centered about the central longitudinal axis.

8. The cable sealing unit of claim 7, wherein the shell includes internal longitudinal ribs that embed in the sealant material to assist in securing the sealant material to the first and second shell pieces. 11

9. The cable sealing unit of claim 5, wherein the shell includes internal longitudinal containment walls that prevent the sealant material from fdling a central section of the first interior region of the shell during molding of the sealant material within the shell.

10. The cable sealing unit of claim 9, wherein the sealant material includes longitudinal seam sealing portions that extend along the length of the shell between the internal longitudinal containment walls and the first and second edges of the shell.

11. The cable sealing unit of claim 1, wherein the shell defines side ports in fluid communication with outer cavities, and wherein the sealant material flows through the side ports and into the outer cavities during molding of the sealant material and assist in providing retention of the sealant material with respect to the first and second shell pieces.

12. The cable sealing unit of claim 1, wherein the shell defines a unitary hinge between the first and second shell pieces at the first longitudinal seam of the shell and defines a snap-fit connection interface between the first and second shell pieces at the second longitudinal seam of the shell.

13. The cable sealing unit of claim 1, wherein the cable sealing unit is IP68 rated.

14. The cable sealing unit of claim 1, wherein the cable sealing unit can accommodate a cable diameter range of at 3, 4 or 5 millimeters. 12

15. The cable sealing unit of claim 1, wherein the elastomeric sealant material includes rubber.