Hybrid communications cable for enhancement of transmission capability

• US 5,448,669 A
• Filed: 12/21/1993
• Issued: 09/05/1995
• Est. Priority Date: 03/24/1992
• Status: Expired due to Fees

• Current Assignee: Fitel USA Corporation
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Mitchell, David M., Dunn, Lawrence R., Woog, Peter A., Mohalley, Robert P., Hardwick, Nathan E. III
• Primary Examiner(s): Bovernick, Rodney B.
• Assistant Examiner(s): Palmer, Phan T. H.
• Application Number:
  US08/171,885
• Time in Patent Office: 623 Days
• Field of Search: 385/100, 385/101, 385/102, 385/103, 385/107, 174/117 R, 174/117 F, 174/115, 174/17 R
• US Class Current: 385/101
• CPC Class Codes: G02B 6/4416 Heterogeneous cables
• CPC Class Codes: G02B 6/4422 of the overhead type
• CPC Class Codes: G02B 6/4431 with provision in the protective covering, e.g. weak line, for gaining access to one or more fibres, e.g. for branching or tapping break-out terminations G02B6/4471
• CPC Class Codes: H01B 11/22 Cables including at least one electrical conductor together with optical fibres

Abstract

A hybrid cable (20) includes a first transmission portion such as a metallic conductor portion (22) and a second transmission portion such as an optical fiber portion (24). The metallic conductor portion includes a core which includes twisted pairs of metallic conductors enclosed in a plastic core wrap, a shielding system and a plastic jacket (48). A longitudinally extending duct (52) is disposed in engagement with an outer surface of the plastic jacket of the metallic conductor portion. An outer plastic jacket (60) is disposed about the duct and the metallic conductor portion. An optical fiber cable (50) or optical fibers (51, 51) may be caused to become disposed initially in the duct or when the use of fibers becomes economically justified.

Claims

1. A hybrid cable, which comprises:

a first transmission portion which comprises a plurality of twisted pairs of metallic conductors and which is disposed within a sheath system;

a second transmission portion which includes a duct which is adapted to receive an optical fiber transmission medium after the duct is formed and which is disposed outside said sheath system of said first transmission portion;

waterblocking provisions which include a superabsorbent material within at least one of the transmission portion; and

means for holding together said first and second transmission portions.

2. The hybrid cable of claim 1, wherein the holding means is an outer sheath system disposed about said first and second transmission portions.

3. The hybrid cable of claim 1, wherein said duct has an outer diameter which is less than the outer diameter of said metallic conductor portion.

4. The hybrid cable of claim 1, wherein said duct has an outer diameter which is greater than the outer diameter of said metallic conductor portion.

5. The hybrid cable of claim 1, wherein said metallic conductor portion includes a core wrap comprising a strip of plastic material which has been wrapped about said plurality of twisted pairs of insulated metallic conductors.

6. The hybrid cable of claim 5, wherein said metallic conductor portion also includes a shielding system which is disposed between said plastic jacket and said plurality of twisted pairs of insulated metallic conductors.

7. The hybrid cable of claim 1, wherein said duct is contiguous to an outer surface of said jacket of said metallic conductor portion.

8. The hybrid cable of claim 1, wherein said duct and said jacket of said metallic conductor portion are spaced apart and are joined by a plastic web extending therebetween.

9. The hybrid cable of claim 1, wherein said cable includes two ducts each of which is disposed outside said jacket of said first transmission portion and each being capable of having optical transmission media received therein, said means including an outer jacket enclosing said first transmission portion and said two ducts.

10. The hybrid cable of claim 9, which also includes a plurality of optical fibers which are disposed in one of said ducts.

11. The hybrid cable of claim 1, wherein said cable includes an optical fiber cable disposed in said duct and wherein said waterblocking provisions includes a filling material which is disposed in said optical fiber cable.

12. The hybrid cable of claim 1, wherein said waterblocking provisions includes a longitudinally extending tape which includes a superabsorbent material.

13. The hybrid cable of claim 1, wherein a longitudinally extending tape is disposed within said duct and is used to pull optical fiber or optical fiber cable into the duct.

14. The hybrid cable of claim 1, wherein said means includes an outer jacket, said hybrid cable also including an aerial support portion which includes a longitudinally extending strength member and a jacket which is disposed about said longitudinally extending strength member and which is connected to said outer jacket by a web which is made of plastic material.

15. The hybrid cable of claim 1, which also includes means for transmitting electrical power.

16. The hybrid cable of claim 1, wherein said means includes an outer jacket which has a circular cross section transverse of a longitudinal axis of said cable.

17. The hybrid cable of claim 16, wherein said cable includes a longitudinally extending metallic tube which is interposed between said duct and first transmission portion and said outer jacket and wherein an outer surface of said metallic tube is provided with an adhesive material which causes said outer jacket to be adhered to said metallic tube.

18. The hybrid cable of claim 1, which also includes optical fiber transmission media disposed in said duct.

19. The hybrid cable of claim 18, wherein the ratio of the transverse cross sectional areas of optical fiber which becomes disposed within said duct to a transverse cross sectional area defined by an inner surface of said duct is in the range of about 0.1 to 0.5.

20. The hybrid cable of claim 1, wherein the length of said duct and of said first transmission portion are unequal in a final installation.

21. The hybrid cable of claim 20, wherein said duct is coupled to an extension duct through an alignment sleeve.