Fiber optic cable breakout configuration with retention block

• US 7,317,863 B2
• Filed: 07/21/2006
• Issued: 01/08/2008
• Est. Priority Date: 03/09/2006
• Status: Expired due to Fees

• Current Assignee: CommScope Technologies, LLC (CommScope Holding Company, Inc.)
• Original Assignee: ADC Telecommunications Incorporated (TE Connectivity Limited)
• Inventors: Lu, Yu, Millea, Keith, Gniadek, Jeff
• Primary Examiner(s): Connelly-Cushwa; Michelle
• Assistant Examiner(s): ROJAS, OMAR R
• Application Number:
  US11/491,336
• Publication Number:
  US 20070212009A1
• Time in Patent Office: 536 Days
• Field of Search: None
• US Class Current: 385/135
• CPC Class Codes: G02B 6/4472 Manifolds
• CPC Class Codes: G02B 6/4475 with provision for lateral branching G02B6/4431 takes precedence
• CPC Class Codes: G02B 6/4476 with heat-shrinkable elements

Abstract

The present disclosure relates to a telecommunications cable including a distribution cable and a tether that branches from the distribution cable at a mid-span breakout location. A flexible closure covers the mid-span breakout location. Within the closure, fibers are broken out from the distribution cable and spliced to fibers of the tether. The lengths of broken out fibers within the flexible closure are provided with sufficient excess fiber length to allow the closure to be readily bent/flexed in any direction without damaging the fibers.

Claims

1. A telecommunications cable comprising:

a distribution cable including a cable jacket and a plurality of buffer tubes positioned within the cable jacket, the plurality of buffer tubes including a first buffer tube, the distribution cable including a mid-span location where a portion of the cable jacket has been removed and where at least the first buffer tube includes a fiber access location;

a closure including an overmold that surrounds the distribution cable and covers the mid-span location, the closure being factory installed, the overmold being elongated along a length that extends along the distribution cable;

a tether that branches from the distribution cable at the closure, the tether including a tether jacket, a tether buffer tube positioned within the jacket and at least one strength member;

a tether retention block affixed to the distribution cable, the tether buffer tube passing through the retention block and at least the strength member of the tether being affixed to the retention block, the overmold covering at least a portion of the tether retention block;

a first optical fiber that extends through the first buffer tube of the distribution cable, the first optical fiber being routed out of the first buffer tube through the fiber access location;

a second optical fiber that extends through the tether buffer tube, the second fiber being routed into the closure; and

the first optical fiber being spliced to the second optical fiber at a splice location located within the closure to form a spliced length of optical fiber extending through the closure.

2. The telecommunications cable of claim 1, wherein the spliced length of optical fiber has an excess fiber length range of about 2-5%.

3. The telecommunications cable of claim 1, wherein the tether retention block is strapped to the distribution cable.

4. The telecommunications cable of claim 1, wherein the tether retention block is clamped to the distribution cable.

5. The telecommunications cable of claim 1, wherein a portion of the retention block is not covered by the overmold.

6. The telecommunications cable of claim 1, wherein a mechanical interlock exists between the retention block and the overmold.

7. The telecommunications cable of claim 6, wherein the mechanical interlock includes a groove defined about an exterior of the tether retention block, and the mechanical interlock also includes a portion of the overmold that is molded into the groove.

8. The telecommunications cable of claim 1, wherein the strength member is adhesively affixed to the tether retention block.

9. The telecommunications cable of claim 8, wherein the tether buffer tube is adhesively secured to the tether retention block.

10. The telecommunications cable of claim 9, wherein the tether retention block defines a first groove for receiving the strength member and a second groove for receiving the tether buffer tube.

11. The telecommunications cable of claim 1, wherein the tether retention block includes a sleeve in which a jacketed portion of the tether is received, a first groove for receiving a portion of the strength member that extends beyond the jacketed portion of the tether, and a second groove for receiving a portion of the tether buffer tube that extends beyond the jacketed portion of the tether.

12. The telecommunications cable of claim 11, wherein the strength member and the tether buffer tube are respectively adhesively secured within the first and second grooves.

13. The telecommunications cable of claim 1, wherein the tether has a flat cable configuration including first and second strength members positioned on opposite sides of the tether buffer tube, wherein the tether retention block includes a sleeve in which a jacketed end portion of the tether is received, wherein the retention block also defines a central channel and two side channels positioned on opposite sides of the central channel, wherein portions of the strength members that extend beyond the jacketed end portion of the tether are received within the side channels of the retention block, and wherein a portion of the tether buffer tube that extends beyond the jacketed end portion of the tether is received within the central channel of the retention block.

14. The telecommunications cable of claim 13, wherein the retention block includes a base and a cover, wherein the side channels of the retention block are defined by opposing grooves provided at the base and at the cover, wherein the central channel is defined by opposing grooves provided at the base and the cover, and wherein adhesive is provided between the base and the cover.

15. The telecommunications cable of claim 1, wherein the telecommunications cable is sized to be pulled through a conduit having a 1.25 inch inner diameter.

16. The telecommunications cable of claim 1, wherein the tether is a stub cable or a drop cable.

17. A telecommunications cable comprising:

a distribution cable including a distribution cable jacket and a plurality of buffer tubes positioned within the cable jacket, the plurality of buffer tubes including a first buffer tube, the distribution cable including a mid-span location where a portion of the distribution cable jacket has been removed and where at least the first buffer tube includes a fiber access location;

a tether that branches from the distribution cable, the tether including a tether jacket, a tether buffer tube positioned within the jacket and at least one strength member;

a tether retention block affixed to the distribution cable, the tether buffer tube passing through the retention block and at least the strength member of the tether being affixed to the retention block;

a protective sleeve that extends along the mid-span location wherein the portion of the distribution cable jacket has been removed, the protective sleeve including a first end that overlaps the distribution cable jacket and a second end that overlaps the tether retention block;

an overmold that covers the protective sleeve;

a first optical fiber that extends through the first buffer tube of the distribution cable, the first optical fiber being routed out of the first buffer tube through the fiber access location;

a second optical fiber that extends through the tether buffer tube, the second fiber being routed into the flexible closure; and

the first optical fiber being spliced to the second optical fiber at a splice location located within the protective sleeve.

18. The telecommunications cable of claim 17, further comprising clips for securing the protective sleeve to the distribution cable.

19. The telecommunications cable of claim 17, further comprising stiffeners for providing the protective sleeve with regions of increased crush resistance.

20. The telecommunications cable of claim 19, wherein the stiffeners are separate pieces from the protective sleeve.