Method and apparatus for anchoring an optical fiber cable

• US 5,835,658 A
• Filed: 09/06/1996
• Issued: 11/10/1998
• Est. Priority Date: 03/20/1995
• Status: Expired due to Term

• Current Assignee: Minnesota Mining and Manufacturing Co (3M Company)
• Original Assignee: PSI Telecommunications, Inc.
• Inventors: Smith, Donald J
• Primary Examiner(s): Sanghavi, Hemang
• Application Number:
  US08/706,677
• Time in Patent Office: 795 Days
• Field of Search: 385/134-137, 385/95-99, 174/74 R, 174/77 R, 174/92, 174/93
• US Class Current: 385/136
• CPC Class Codes: G02B 6/4444 Seals
• CPC Class Codes: G02B 6/4446 Cable boxes, e.g. splicing boxes with two or more multi fibre cables
• CPC Class Codes: G02B 6/4447 with divided shells G02B6/4448 takes precedence
• CPC Class Codes: G02B 6/4471 Terminating devices demountable connectors G02B6/3807; Cable clamps
• CPC Class Codes: G02B 6/44765 with means for strain-relieving to exterior cable layers
• CPC Class Codes: G02B 6/4477 with means for strain-relieving to interior strengths element
• CPC Class Codes: G02B 6/44775 Cable seals e.g. feed-through cable seals integrated to the box seals G02B6/4444; pulling eyes G02B6/44465
• CPC Class Codes: H02G 15/007 Devices for relieving mechanical stress
• CPC Class Codes: H02G 15/013 Sealing means for cable inlets inlets for cables filled with, or surrounded by, gas or oil H02G15/32
• CPC Class Codes: H02G 15/113 Boxes split longitudinally in main cable direction
• CPC Class Codes: H02G 15/117 for multiconductor cables

Abstract

The fiber optic cable adapter spool is formed to be retained within an end plate assembly of a wire cable splice closure assembly. The adapter spool provides a cable entrance port capable of supporting an optical fiber cable in conventional telecommunication applications. The fiber optic cable is wrapped with a high coefficient of friction, adhesively-backed tape and a layer of mastic sealant before placed in the cable entrance port. The cable entrance port has two sets of annular gripping teeth and a plurality of annular sealing ribs located between the sets of annular gripping teeth. Once the cable has been placed into a cable entrance port, the adapter spool is contracted to cause the two sets of annular gripping teeth to exert radial pressure into either end of the wrapped portion of the cable. Similarly, during contraction, the layer of mastic sealant around the tape, positioned between the gripping teeth, cooperates with the sealing ribs between the gripping teeth to form a seal between the tape and the cable entrance port. The fiber optic adapter spool therefore restrains the optical fiber cable sheath within the splice closure while providing a seal between the cable and the end plate.

Claims

1. A splice closure assembly for an optical fiber cable splice which cable comprises an optical fiber cable sheath, a central strength member, and a plurality of optical fibers between the cable sheath and the central strength member, said splice closure assembly comprising:

an end plate assembly having an opening;

a cover removably attached to said end plate assembly;

means for anchoring the central strength member, said means for anchoring rigidly coupled to said end plate assembly; and

means for securing the optical fiber cable sheath to the means for anchoring.

2. A splice closure assembly according to claim 1, wherein said means for anchoring the central strength member comprises:

a bracing member;

a slotted bracket for securing said bracing member to said end plate assembly; and

a cantilevered member integrally formed with said bracing member having means for retaining the central strength member.

3. A splice closure according to claim 2, wherein said means for retaining the central strength member further comprises:

an anchor bolt having a head and an anchor bolt retaining means; and

an anchoring platform having raised perpendicular walls and a central anchor bolt opening, wherein the central strength member is secured to said anchoring platform between said head of said anchor bolt, said parallel raised perpendicular wall of said anchoring platform and said anchoring platform by actuating said anchor bolt retaining means.

4. A splice closure assembly according to claim 2, wherein said means for securing the optical fiber cable sheath comprises a hose clamp secured around the optical fiber cable sheath and said cantilevered member of said means for anchoring and tightened to provide sufficient radial force against said combination of optical fiber cable sheath and said cantilevered member to further restrain the fiber optic cable sheath within the closure.

5. A splice closure assembly as set out in claim 1, wherein said end plate assembly has a plurality of openings for receiving a plurality of optical fiber cables and wherein a plurality of separate anchoring means are provided, equal in number to the number of openings in the end plate assembly, each of said plurality of anchoring means being separately rigidly coupled to the end plate assembly.

6. A splice closure assembly as set out in claim 5, wherein each of said separate anchoring means are configured adjacent to a respective one of the openings in the end plate assembly.

7. A splice closure assembly as set out in claim 6, wherein at least a portion of each of the anchoring means is aligned with a corresponding one of the openings.

8. A splice closure assembly as set out in claim 7, wherein each of the anchoring means comprises a cantilevered member and wherein one portion of the cantilevered member is secured to the end plate assembly and the other portion extends into the interior of the closure along a line aligned with a corresponding one of the openings in the end plate assembly.

9. A splice closure assembly as set out in claim 7, wherein the plurality of anchoring means are spaced annularly about the end plate assembly with an angular spacing corresponding to the spacing of the openings in the end plate assembly.

10. A fiber optic cable anchor assembly for securing an optical fiber cable to an end plate assembly, the optical fiber cable having an optical fiber cable sheath, a central strength member, and a plurality of optical fibers between the cable sheath and the central strength member, the anchor assembly comprising:

a bracing member for securing the anchor assembly to an end plate assembly;

a cantilevered member having a proximal end and a distal end, said cantilevered member integrally formed with said bracing member at said proximal end to project away from the end plate assembly, wherein said cantilevered member includes means for retaining the central strength member at said distal end of said cantilevered member; and

a clamp for securing the optical fiber cable sheath to the cantilevered member.

11. An anchor assembly according to claim 10, wherein said means for retaining the central strength member further comprises:

an anchoring platform having an anchor bolt opening and at least one raised portion proximate said anchor bolt opening formed generally perpendicular to the end plate assembly; and

an anchor bolt having a head and means for retaining said anchor bolt,

wherein the central strength member is retained in an area formed between said anchoring platform, said anchor bolt, said head of said anchor bolt and said at least one raised portion of said anchoring platform by actuating said means for retaining said anchor bolt.

12. A fiber optic cable anchor assembly according to claim 10, wherein said clamp is secured around the circumference of the cantilevered member and the cable sheath, and is configured so as to be tightened around said sheath against radial force without damaging the optical fibers within the optical fiber cable to prevent substantial movements of the cable sheath relative to the end plate assembly.

13. A method for anchoring an optical fiber cable to an end plate assembly having a cable entrance port, the optical fiber cable having an optical fiber cable sheath, a plurality of optical fibers and a central strength member, the method for anchoring an optical fiber cable comprising the steps of:

securing an anchor assembly to the end plate assembly proximate a cable entrance port, wherein said anchor assembly comprises a rigid, integrally formed bracing member and cantilevered member, wherein said cantilevered member includes an anchoring platform;

exposing a portion of the central strength member of an optical fiber cable;

inserting the optical fiber cable through a cable entrance port of an end plate assembly;

securing the central strength member to said anchoring platform of the cantilevered member at a first location; and

securing a clamp around the cable sheath and the cantilevered member at a second location adjacent the first location and closer to the end plate assembly than the first location to secure the cable sheath to the cantilevered member to prevent movement of the cable sheath relative to the end plate assembly.

14. A method for anchoring as set out in claim 13, wherein the end plate assembly has a plurality of cable entrance ports and wherein said step of securing an anchor assembly proximate a cable entrance port is repeated for each of said plurality of cable entrance ports.

15. A method as set out in claim 13, wherein a separate optical fiber cable is provided for each cable entrance port and wherein said steps of exposing a portion of the central strength member of an optical fiber cable, inserting the optical fiber cable through a cable entrance port of an end plate assembly, securing the strength member to said anchoring platform of the cantilevered member, and securing a clamp around the cable sheath and the cantilevered member to secure the cable sheath to the cantilevered member to prevent movement of the cable sheath relative to the end plate assembly, are repeated a plurality of times equal in number to the number of cables and cable entrance ports.