Force transfer system for an optical fiber connector

• US 5,418,874 A
• Filed: 01/19/1994
• Issued: 05/23/1995
• Est. Priority Date: 01/19/1994
• Status: Expired due to Fees

• Current Assignee: Fitel USA Corporation
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Granger, Wayne D., Hicks, Jeffrey H., Carlisle, Arthur W.
• Primary Examiner(s): Healy, Brian
• Application Number:
  US08/184,623
• Time in Patent Office: 489 Days
• Field of Search: 385/60, 385/62, 385/76, 385/77, 385/78, 385/81, 385/84, 385/87, 385/139
• US Class Current: 385/76
• CPC Class Codes: G02B 6/3878 comprising a plurality of ferrules, branching and break-out means
• CPC Class Codes: G02B 6/3888 Protection from over-extension or over-compression

Abstract

An optical fiber connector includes a wedge for gripping one or more buffered optical fibers. The wedge comprises a body portion having an opening that extends through it from one end to the other through a longitudinal axis of the wedge for receiving the pair of optical fibers contained within a cable. The wedge further includes a pair of flexible cantilevers that extend from one end of the body portion along a direction that is parallel to the longitudinal axis. Each cantilever includes an inner surface that faces the inner surface of the other cantilever, and each inner surface includes an like number of grooves that are parallel to each other and perpendicular to the longitudinal axis of the wedge. The grooves grip the pair of buffered optical fibers when compressed by crimping a surrounding bushing, and thereby restrain the optical fibers from being pulled back into the cable during handling. The cantilevers are symmetrically positioned on opposite sides of a plane which contains the longitudinal axis of the wedge.

Claims

1. A force transfer system comprising a wedge disposed within a bushing for gripping one or more optical fibers, the bushing having an interior passageway which is shaped to receive the wedge;

the wedge including a body portion having a pair of flexible cantilevers that are parallel to each other and extend from one end of the body portion, each cantilever having an inner surface which faces the inner surface of the other cantilever, the inner surfaces of the cantilevers including a plurality of grooves that are parallel to each other and perpendicular to a central axis of the wedge.

2. The force transfer system of claim 1 wherein the bushing and the wedge are generally cylindrical shapes whose central axes are coincident when the wedge is disposed within the bushing.

3. The force transfer system of claim 2 wherein the interior passageway of the bushing and an exterior surface of the body portion of the wedge are tapered at substantially the same angle in the direction of the central axis.

4. A connector for terminating a cable containing a first optical fiber surrounded by a buffer material, the connector including a first plug assembly which comprises (i) a cylindrically shaped ferrule having a passageway through a central axis thereof for receiving a first optical fiber, (ii) a barrel member, also having a passageway through a central axis thereof for receiving the first optical fiber, and (iii) a spring member disposed about the barrel member CHARACTERIZED BY:

a wedge including a pair of flexible cantilevers that extend from a body portion thereof along its longitudinal axis, each cantilever comprising an inner surface which generally faces the inner surface of the other cantilever, at least one of said inner surfaces including one or more grooves for gripping the first optical fiber; and

means engaging the outside surfaces of said cantilevers such that a force is imparted on the cantilevers in a direction which urges them together;

whereby the first optical fiber is held within the connector by the wedge, member.

5. The connector of claim 4 wherein the means engaging the cantilevers comprises a cylindrical member which surrounds said cantilevers and is adapted to be crimped at one end thereof.

6. The connector of claim 4 wherein the inner surface of each cantilever includes an equal number of grooves that are parallel to each other but perpendicular to the longitudinal axis of the wedge.

7. The connector of claim 6 wherein the grooves are positioned along the inner surfaces of the cantilevers as mirror images of each other;

whereby microbending of the optical fiber is avoided.

8. The connector of claim 4 wherein the wedge is made from a glass-filled polyetherimide material.

9. The connector of claim 8 wherein glass comprises approximately 30% of the wedge.

10. The connector of claim 4 further including a second plug assembly which comprises (i) a cylindrically shaped ferrule having a passageway through a central axis thereof for receiving a second optical fiber of the cable, (ii) a barrel member, also having a passageway through a central axis thereof for receiving the second optical fiber, and (iii) a spring member disposed about the barrel member.

11. The connector of claim 10 wherein the wedge is adapted to receive said first and second optical fibers, the free end of each cantilever including a pair of semicircularly shaped channels that cooperate with the semicircularly shaped channels of the other cantilever to restrain lateral movement of the optical fiber pair.

12. A duplex optical fiber connector for terminating two optical fibers of a cable and being adapted to be joined to another connector, said duplex connector comprising:

a housing which includes a cable-entrance end and a plug end;

force transfer means positioned adjacent to the cable-entrance end of the housing through which the optical fibers extend for transferring tensile force applied to the optical fibers to the housing, said force transfer means including a wedge member through which the optical fibers extend and which is effectively linked to the housing for the purpose of communicating tensile forces thereto, the wedge member comprising a body portion and a pair of flexible cantilevers extending from one end thereof that are parallel to a longitudinal axis of the wedge and are positioned on diametrically opposite sides of said axis, said force transfer means further including means for applying an orthogonal force to the flexible cantilevers which causes them to move together and capture the optical fibers therebetween; and

a plug assembly positioned adjacent to the plug end of the housing and adapted to be associated with each of the optical fibers, each plug assembly including a ferrule for terminating one of the optical fibers of the cable.

13. A simplex optical fiber connector for terminating an optical fiber of a cable and being adapted to be joined to another connector, said simplex connector comprising:

a housing which includes a cable-entrance end and a plug end;

force transfer means positioned adjacent to the cable-entrance end of the housing through which the optical fiber extends for transferring tensile force from the optical fiber to the housing, said force transfer means including a wedge member through which the optical fiber extends and which is effectively linked to the housing for the purpose of communicating tensile forces thereto, the wedge member comprising a body portion and a pair of flexible cantilevers extending from one end thereof that are parallel to a longitudinal axis of the wedge and are positioned on diametrically opposite sides of said axis, said force transfer means further including means for applying an orthogonal force to the flexible cantilevers which causes them to move together and capture the optical fiber therebetween; and

a plug assembly positioned adjacent to the plug end of the housing and adapted to be associated with the optical fiber, the plug assembly including a ferrule for terminating the optical fiber and a barrel member for holding the ferrule.

14. In combination, an optical fiber cable and a connector for same,

the optical fiber cable comprising:

a first optical fiber surrounded by a plurality of non-metallic filamentary strength members, said strength members extending in the same longitudinal direction as the first optical fiber and being enclosed within a dielectric outer jacket;

the connector comprising;

a housing which includes a cable-entrance end and a plug end;

force transfer means positioned adjacent to the cable-entrance end of the housing through which the first optical fiber extends for transferring tensile force from the first optical fiber to the housing, said force transfer means including a wedge member through which the optical fiber extends and which is effectively linked to the housing for the purpose of communicating tensile forces thereto, the wedge member comprising a body portion and a pair of flexible cantilevers extending from one end thereof that are parallel to a longitudinal axis of the wedge and are positioned on diametrically opposite sides of said axis, said force transfer means further including means for applying an orthogonal force to the flexible cantilevers which causes them to move together and capture the optical fiber therebetween; and

a first plug assembly positioned adjacent to the plug end of the housing and adapted to be associated with the optical fiber, the first plug assembly including a first ferrule for terminating the first optical fiber and a first barrel member for holding the first ferrule.

15. The combination of claim 14 wherein the housing further includes a second plug assembly positioned adjacent to the plug end of the housing and adapted to be associated with a second optical fiber of the cable, the second plug assembly including a second ferrule for terminating the second optical fiber and a second barrel member for holding the second ferrule.