Water blocking strength members

• US 5,389,442 A
• Filed: 11/25/1992
• Issued: 02/14/1995
• Est. Priority Date: 07/11/1988
• Status: Expired due to Term

• Current Assignee: Furukawa Electric North America Incorporated (Furukawa Electric Company Limited)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Fluevog, Jill B., Patel, Parbhubhai D., Kathiresan, Krishnaswamy, Arroyo, Candido J.
• Primary Examiner(s): Ryan, Patrick J.
• Assistant Examiner(s): GRAY, JILL M
• Application Number:
  US07/982,252
• Time in Patent Office: 811 Days
• Field of Search: 428/377, 428/375, 428/395, 428/394, 174/107, 174/23 C, 174/23 A, 174/70 S, 57/243, 385/100, 385/113
• US Class Current: 428/396
• CPC Class Codes: G02B 6/4432 with fibre reinforcements
• CPC Class Codes: G02B 6/44384 the means comprising water blocking or hydrophobic materials G02B6/4439, G02B6/4479 take precedence
• CPC Class Codes: H01B 7/288 using hygroscopic material or material swelling in the presence of liquid
• CPC Class Codes: Y10T 428/2933 Coated or with bond, impregnation or core
• CPC Class Codes: Y10T 428/2938 Coating on discrete and individual rods, strands or filaments
• CPC Class Codes: Y10T 428/2967 Synthetic resin or polymer
• CPC Class Codes: Y10T 428/2969 Polyamide, polyimide or polyester
• CPC Class Codes: Y10T 428/2971 Impregnation

Abstract

A communications cable (20) comprising a core (22) of at least one transmission media and a plastic jacket (34) includes provisions for preventing the movement of water within the cable. The cable includes a strength system (32) including longitudinally extending fibrous strength members (33--33) having a relatively high modulus and having water blocking provisions. In one embodiment, each fibrous strength member is treated with a superabsorbent liquid material which when dry fills interstices and covers portions of the exterior thereof. In another embodiment, a filamentary strand material comprising a water swellable fibrous material is wrapped about each fibrous strength member.

Claims

1. A waterblocking strength member for use in an optical fiber communications cable, said waterblocking strength member comprising:

an elongated, supple yarn which is impregnated with a superabsorbent material and which has a breaking strength greater than 400 Newtons.

2. The strength member of claim 1, wherein said superabsorbent material coats each filament of said yarn.