OPTICAL FIBER CONNECTOR

• US 20140133808A1
• Filed: 11/12/2013
• Published: 05/15/2014
• Est. Priority Date: 11/14/2012
• Status: Active Grant

• Current Assignee: Clearfield, Inc
• Original Assignee: John P. Hill, Walter E. Power, II
• Inventors: HILL, John P., POWER, Walter E. II, NISHIGUCHI, Yuki
• Granted Patent: US 9,297,976 B2
• Time in Patent Office: Days
• US Class Current: 385/81
• CPC Class Codes: G02B 6/2804 forming multipart couplers without wavelength selective elements, e.g. "T" couplers, star couplers
• CPC Class Codes: G02B 6/3821 with axial spring biasing or loading means G02B6/3847 takes precedence
• CPC Class Codes: G02B 6/3826 characterised by form or shape
• CPC Class Codes: G02B 6/3849 using mechanical protective elements, e.g. caps, hoods, sealing membranes G02B6/3816 takes precedence; provisionally see H01R13/44
• CPC Class Codes: G02B 6/3857 Crimping, i.e. involving plastic deformation
• CPC Class Codes: G02B 6/3874 using tubes, sleeves to align ferrules
• CPC Class Codes: G02B 6/3878 comprising a plurality of ferrules, branching and break-out means
• CPC Class Codes: G02B 6/3879 Linking of individual connector plugs to an overconnector, e.g. using clamps, clips, common housings comprising several individual connector plugs
• CPC Class Codes: G02B 6/3893 Push-pull type, e.g. snap-in, push-on
• CPC Class Codes: G02B 6/3897 Connectors fixed to housings, casing, frames or circuit boards G02B6/44528 takes precedence
• CPC Class Codes: G02B 6/44 Mechanical structures for providing tensile strength and external protection for fibres, e.g. optical transmission cables cables incorporating electric conductors and optical fibres where features relating to the optical fibres are not of interest H01B11/22
• CPC Class Codes: G02B 6/4442 Cap coupling boxes
• 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 6/4452 Distribution frames
• CPC Class Codes: G02B 6/4473 Three-way systems
• CPC Class Codes: G02B 6/46 Processes or apparatus adapted for installing or repairing optical fibres or optical cables installation of cables containing electric conductors and optical fibres H02G
• CPC Class Codes: G02B 6/545 Pulling eyes G02B6/475 takes precedence
• CPC Class Codes: Y10T 29/49826 Assembling or joining

Abstract

An optical fiber connector and method for assembly and use are disclosed. The optical fiber connector is configured to have a small footprint so that the connector may be pushable or pullable through a conduit if use of a conduit may be needed. The connector may include a first number of connector components configured to fit through a conduit, and a second number of connector components that are configured to be installed to the first components, for example, after the connector is pushed or pulled through a conduit.

Claims

1. A terminal end assembly for an optic fiber cable, the assembly comprising:

a ferrule assembly comprising;

a ferrule for receiving and terminating an optic fiber of an optic fiber cable, and a ferule holder having a first end for receiving the optic fiber therethrough, and a second end opposite the first end for receiving and retaining the ferrule therein;

a tubular connector body having a first end configured for receiving and retaining a terminal end of a fiber optic cable therein, and a second end configured for slidably receiving the ferrule holder therein, the ferrule holder being axially movable within the second end for movement of the ferrule towards and away from the connector body;

a biasing member for being disposed within the connector body for biasing the ferrule holder axially away from the connector body; and

a ferrule retainer for retaining the ferrule holder within the second end of the connector body, the retainer comprising a tubular body for being disposed around the ferrule and ferrule holder, and the tubular body having a first end configured for engaging with the connector body for retaining the ferrule holder with the connector body, and a second end configured for limiting movement of the ferrule holder axially away from the connector body in opposition to the biasing, wherein the ferrule retainer and the tubular connector body together form an encasement for encasing the biasing member and ferrule retainer.

2. The terminal end assembly according to claim 1, further comprising an end cap for being disposed around the ferrule and in engagement with the ferrule retainer, the end cap having a first end for receiving the ferrule therein and a second closed end opposite the first end, and the end cap, the ferrule retainer and the tubular connector body together form a capsule encasing the biasing member, the ferrule retainer and the ferrule.

3. The terminal end assembly according to claim 2, wherein:

the ferrule has an external cylindrical surface, the end cap has an internal cylindrical surface, and the internal cylindrical surface of the end cap is configured to frictionally engage with the external cylindrical surface of the ferrule to retain the end cap on the ferrule; and

at least one of the ferrule retainer and the end cap comprises an engagement portion for engaging with the other of the ferrule retainer and the end cap to prevent rotation of the end cap about the ferrule.

4. The terminal end assembly according to claim 2, wherein the end cap, the ferrule retainer and at least a portion of the connector body each define a cylindrical surface disposed about a longitudinal axis, at least one of the cylindrical surface of the end cap, the ferrule retainer and the at least a portion of the connector body defines a maximum radius, and the at least one of the cylindrical surface of the end cap, the ferrule retainer and the at least a portion of the connector body are configured to have maximum radius that allows the terminal end assembly to fit through a microconduit.

5. The terminal end assembly according to claim 4, wherein the microconduit is a bend limited microconduit having an internal diameter of less than about 10 mm.

6. The terminal end assembly of claim 1, wherein the first end of the ferrule retainer is configured for frictionally engaging with the second end of the connector body when disposed on the connector body for retaining the ferrule holder with the connector body against the biasing of the ferrule holder.

7. The terminal end assembly of claim 6, wherein a the ferrule retainer defines an internal diameter, the second end of the connector body defines an external diameter, and the internal diameter is less than the external diameter for frictional engagement of the ferrule retainer with the connector body.

8. The terminal end assembly of claim 1, wherein:

the first end of the connector body comprises a crimp tube configured for being crimped to a fiber optic cable;

the first end of the ferrule retainer frictionally engages with the second end of the connector body for retaining the ferrule holder with the connector body against the biasing of the ferrule holder;

the biasing member comprises a spring for being disposed about the first end of the ferrule holder;

the connector body comprises an internal circumferential edge configured for supporting the spring within the connector body;

the ferrule holder comprises an external circumferential edge configured for bearing the biasing of the spring;

at least one of the second end of the connector body and the ferrule holder comprises a device for preventing rotation of the ferrule holder within the connector body;

the assembly further comprises an end cap for being disposed around the ferrule and in engagement with the ferrule retainer, the end cap having a first end for receiving the ferrule therein, a second closed end opposite the first end, and a body portion disposed between the first end and the second end, wherein an exterior of the end cap at the second end is hemispherical, and the body portion comprises at least one indentation configured for enhancing gripping of the end cap;

the end cap, the ferrule retainer and at least a portion of the connector body are configured to together completely surround and enclose the ferrule, ferrule holder, and spring; and

the end cap, the ferrule retainer and at least a portion of the connector body together define a substantially cylindrical surface of the terminal end assembly.

9. A pre-terminated optical fiber cable comprising at least one optical fiber terminated at at least one end thereof with an encased ferrule assembly of a size configured for being axially movable through a microconduit.

10. The pre-terminated cable according to claim 9, wherein the encased ferrule assembly comprises:

a ferrule holder comprising a ferrule;

a tubular connector body having a first end retaining a terminal end of the optical fiber cable therewith, and a second end disposed about at least a portion of the ferrule holder, the ferrule holder being axially movable within the second end;

a ferrule retainer for retaining the ferrule holder within the second end of the connector body, the retainer comprising a tubular body for being disposed around the ferrule and ferrule holder, and the tubular body having a first end configured for engaging with the connector body for retaining the ferrule holder with the connector body, and a second end disposed around the ferrule and configured for limiting movement of the ferrule holder axially away from the connector body in opposition to the biasing; and

an end cap disposed around the ferrule and in engagement with the ferrule retainer;

wherein the ferrule retainer, the tubular connector body and the end cap together form an encasement surrounding the ferrule retainer and ferrule.

11. The pre-terminated cable according to claim 10, wherein the encased ferrule assembly is of a size configured for being axially movable through a microconduit having an internal diameter of about 6 mm.

12. An optical fiber connector comprising:

a pre-terminated optical fiber cable configured for being pushed or pulled through a conduit, the pre-terminated optical fiber cable comprising;

a fiber optic cable comprising an optic fiber;

a tubular connector body having a first end disposed about an end of the optic cable and retaining the fiber optic cable therein, and a second end opposite the first end;

a ferrule assembly terminating the optical fiber cable, the ferrule assembly comprising;

a ferrule terminating the optic fiber, and a ferrule holder having a first end axially slidably disposed within the second end of the connector body, and a second end opposite the first end and retaining the ferrule therein;

a spring member disposed about the first end of the ferrule holder within second end of the connector body and biasing the ferrule holder axially away from the connector body;

a ferrule retainer retaining the ferrule holder within the second end of the connector body, the retainer comprising a tubular body disposed around the ferrule and ferrule holder, and the tubular body having a first end in engagement with the connector body for retaining the ferrule holder with the connector body, and a second end disposed around the ferrule for limiting movement of the ferrule holder axially away from the connector body in opposition to the biasing; and

an end cap disposed around the ferrule and in engagement with the ferrule retainer;

an inner ferrule housing comprising a central longitudinal cavity configured for receiving the connector body therein, wherein the ferrule housing is axially slidably displaceable over the connector body, and at least one of the ferrule housing and the connector body comprises a first retaining member for releasably engaging and retaining the ferrule housing with the connector body; and

an outer housing configured for mating with an optical fiber socket by push/pull engagement and disengagement, the outer housing comprising a central longitudinal cavity configured for receiving the inner ferrule housing therein, wherein the outer housing is axially slidably displaceable over the ferrule housing, and at least one of the ferrule housing and the outer housing comprises a second retaining member for releasably engaging and retaining the outer housing with the ferrule housing.

13. The connector of claim 12, wherein the connector is an SC-type connector, the outer housing is an SC-connector housing configured for mating with an SC-type socket, the conduit is a microconduit having an internal diameter of about 6 mm, and the preterminated optical fiber cable has a maximum diameter of about 5 mm.

14. The connector of claim 12, wherein:

the ferrule has an external cylindrical surface, the end cap has an internal cylindrical surface, and the internal cylindrical surface of the end cap frictionally engages with the external cylindrical surface of the ferrule to retain the end cap on the ferrule; and

the first end of the ferrule retainer frictionally engages with the second end of the connector body for retaining the ferrule holder with the connector body against the biasing of the ferrule holder.

15. The connector of claim 12, wherein:

the end cap, the ferrule retainer and at least a portion of the connector body completely surround and enclose the ferrule, ferrule holder, and spring; and

the end cap, the ferrule retainer and at least a portion of the connector body together define a substantially cylindrical surface of the pre-terminated optical fiber.

16. The connector of claim 12, wherein:

the first end of the connector body comprises a crimp tube crimped to the fiber optic cable;

the ferrule holder comprises at least two radial extensions defining a channel therebetween, and the second end of the connector body comprises at least one axially extending arm disposed within the channel to prevent rotation of the ferrule holder within the connector body; and

the end cap comprises a first end for receiving the ferrule therein and a second closed end opposite the first end, and an exterior of the end cap at the second end is hemispherical.

17. The connector of claim 12, wherein:

the inner ferrule housing has an internal cylindrical surface configured for receiving the connector body therein;

the connector body has an external cylindrical surface and the external surface comprises at least one notch disposed in a circumferential direction;

the first retaining member comprises a projection on the internal cylindrical surface for releasably engaging with the notch in the axial direction for retaining the ferrule housing with the connector body;

the inner ferrule housing has an external surface having a substantially square cross-section;

the outer housing has an internal cavity with a cross-section corresponding to the cross-section of the ferrule housing and configured for receiving the ferrule housing therein;

the second retaining member comprises at least one axial projection on the external surface of the ferrule housing, and the outer housing comprises at least one surface transverse to the axial direction and configured for engaging with the axial projection for retaining the ferrule housing with the outer housing; and

at least one of the internal cavity of the outer housing and the external surface of the ferrule housing comprising a keying projection and the other of the internal cavity of the outer housing and the external surface of the ferrule housing comprising a corresponding keying recess for receiving the keying projection therein for insertion of the ferrule housing within the outer housing in a only one orientation of the ferrule housing with respect to the outer housing.

18. A method for installation of an optical fiber, the method comprising:

obtaining a pre-terminated optical fiber cable comprising at least one optical fiber terminated at at least one end thereof with an encased ferrule assembly of a size configured for being axially movable through a microconduit;

feeding the pre-terminated optical fiber through a microconduit;

axially sliding an inner ferrule housing over the pre-terminated end and engaging the ferrule housing with the encased ferrule assembly;

axially sliding an outer connector housing over the ferrule housing and engaging the outer connector housing with the ferrule housing; and

mating the outer connector housing with an optical fiber socket.

19. The method of claim 18, wherein the outer connector housing is an SC-connector housing configured for mating with an SC-type socket, the microconduit has an internal diameter of about 6 mm, and the preterminated optical fiber has a maximum diameter of about 5 mm.

20. The method of claim 19, wherein the encased ferrule assembly comprises:

a tubular connector body having a first end disposed about an end of the optic cable and retaining the fiber optic cable therein, and a second end opposite the first end;

a ferrule sub-assembly terminating the optical fiber cable, the ferrule sub-assembly comprising;

a ferrule terminating an optic fiber of the fiber optic cable, and a ferrule holder having a first end axially slidably disposed within the second end of the connector body, and a second end opposite the first end and retaining the ferrule therein;

a spring member disposed about the first end of the ferrule holder within second end of the connector body and biasing the ferrule holder axially away from the connector body;

a ferrule retainer retaining the ferrule holder within the second end of the connector body, the retainer comprising a tubular body disposed around the ferrule and ferrule holder, and the tubular body having a first end in engagement with the connector body for retaining the ferrule holder with the connector body, and a second end disposed around the ferrule for limiting movement of the ferrule holder axially away from the connector body in opposition to the biasing;

an end cap disposed around the ferrule and in engagement with the ferrule retainer, wherein the end cap, the ferrule retainer and the connector body encase the spring member, ferrule retainer and ferrule; and

axially sliding the inner ferrule housing over the pre-terminated end and engaging the ferrule housing with the encased ferrule assembly comprises axially sliding the inner ferrule housing over the connector body and engaging the ferrule housing with the connector body.