U.S. patent application number 11/139734 was filed with the patent office on 2006-11-30 for fiber optic connector having keyed ferrule holder.
Invention is credited to James P. Luther, Thomas Theuerkorn, Hleu V. Tran.
Application Number | 20060269194 11/139734 |
Document ID | / |
Family ID | 37463467 |
Filed Date | 2006-11-30 |
United States Patent
Application |
20060269194 |
Kind Code |
A1 |
Luther; James P. ; et
al. |
November 30, 2006 |
Fiber optic connector having keyed ferrule holder
Abstract
A fiber optic connector including one or more ferrule assemblies
having a ferrule and a keyed ferrule holder defining a first key
slot and a second key slot, and a connector housing defining a key
that is received within the first or the second key slot. The first
key slot configures the connector in a first keyed position for
simultaneous, coplanar end face polishing of the ferrules, and the
second keyed position configures the connector for mating with a
receptacle, optical device or another connector. A fiber optic
connector including a connector outer housing defining a first key
slot for positioning the connector housing in a first keyed
position and a second key slot for positioning the connector
housing in a second keyed position, a connector inner housing
defining a key and a ferrule assembly including a ferrule and a
ferrule holder, wherein the ferrule assembly is biased outwardly
within the connector outer housing. The connector outer housing is
independently positionable between the first keyed position for end
face polishing and the second keyed position for connector
mating.
Inventors: |
Luther; James P.; (Hickory,
NC) ; Theuerkorn; Thomas; (Hickory, NC) ;
Tran; Hleu V.; (Charlotte, NC) |
Correspondence
Address: |
CORNING CABLE SYSTEMS LLC
P O BOX 489
HICKORY
NC
28603
US
|
Family ID: |
37463467 |
Appl. No.: |
11/139734 |
Filed: |
May 27, 2005 |
Current U.S.
Class: |
385/78 ;
385/85 |
Current CPC
Class: |
G02B 6/3849 20130101;
G02B 6/3822 20130101; G02B 6/3871 20130101; G02B 6/3851 20130101;
G02B 6/3863 20130101; G02B 6/3878 20130101 |
Class at
Publication: |
385/078 ;
385/085 |
International
Class: |
G02B 6/36 20060101
G02B006/36 |
Claims
1. A fiber optic connector, comprising: at least one ferrule
assembly comprising at least one optical fiber ferrule defining an
end face, the ferrule positionable between a first polishing
position for polishing the end face and a second mating position
for mating the fiber optic connector; and a connector housing
defining a key, wherein the at least one ferrule assembly defines a
first key slot and a second key slot for engaging the key on the
connector housing, and wherein the at least one ferrule assembly is
movable between the first polishing position with the first key
slot engaging the key and the second mating position with the
second key slot engaging the key.
2. (canceled)
3. The fiber optic connector according to claim 1, further
comprising a biasing member that engages a rear portion of the at
least one ferrule and biases the ferrule outwardly from the fiber
optic connector.
4. The fiber optic connector according to claim 1, comprising two
ferrule assemblies each comprising at least one optical fiber
ferrule defining an end face, each ferrule assembly being
independently positionable relative to the other ferrule assembly
between a first polishing position wherein the end faces of the
ferrules are coplanar and a second mating position wherein the end
faces of the ferrules are not coplanar.
5. The fiber optic connector according to claim 4, wherein the end
faces of the ferrules are coplanar in the first polishing position
for simultaneously polishing the end faces of the ferrules in a
pre-assembled fiber optic connector.
6. The fiber optic connector according to claim 4, further
comprising at least one connector inner housing defining at least
one key, and wherein each ferrule assembly further comprises a
connector outer housing defining a first key slot and a second key
slot, and wherein each ferrule assembly is movable between the fist
polishing position with the first key slot of the respective
connector outer housing engaging a key of the connector inner
housing and the second mating position with the second key slot of
the respective connector outer housing engaging a key of the
connector inner housing.
7. The fiber optic connector according to claim 6, further
comprising a biasing member that engages a rear portion of the at
least one ferrule and biases the ferrule outwardly from the fiber
optic connector.
8. The fiber optic connector according to claim 6, wherein each of
the ferrule assemblies is moved between the first polishing
position and the second mating position by pushing the ferrule
assembly inwardly against the biasing member until the first key
slot clears the key, moving the ferrule assembly between the first
polishing position and the second mating position, and releasing
the ferrule assembly such that the second key slot engages the
key.
9. The fiber optic connector according to claim 1, farther
comprising a plug housing defining an internal cavity opening
through opposed first and second ends for receiving the ferrule
assembly, a flexible sealing boot, a coupling nut, a crimp body and
a crimp band.
10. The fiber optic connector according to claim 1, wherein the
ferrule assembly is rotatable about a longitudinal axis defined by
the ferrule.
11. A fiber optic connector, comprising: a connector housing, and a
pair of ferrule assemblies each being independently movable
relative to the connector housing, each ferrule assembly comprising
at last one ferrule defining an end face and a positionable ferrule
holder defining a first key slot for positioning the end face of
the ferrule in a first polishing position and a second key slot for
positioning the end face of the ferrule in a second mating
position; wherein the connector housing defines at least one key
that is received within the first key slot in the first polishing
position and the second key slot in the second mating position and
operable for maintaining the ferrule assembly in the first
polishing position and the second mating position.
12. The fiber optic connector according to claim 11, wherein the
ferrules of the ferrule assemblies are elected from the group
consisting of an SC angled-physical-contact (APC) ferrule and an LC
angled-physical-contact (APC) ferrule.
13. The fiber optic connector according to claim 11, further
comprising a biasing member that engages a rear portion of the
ferrule assembly and biases the ferrule assembly outwardly from the
connector housing, the biasing member being operable to permit the
ferrule assembly to be pushed inwardly far enough to clear the key
of the connector housing and thereby permit the ferrule holder to
be moved relative to the connector housing.
14. The fiber optic connector according to claim 11, further
comprising a plug housing defining an internal cavity opening
through opposed first and second ends for receiving the ferrule
assemblies and the connector housing, a flexible sealing boot, a
coupling nut, a crimp body and a crimp band.
15. The fiber optic connector according to claim 11, wherein the
first key slot and the second key slot of each ferrule holder are
positioned about 90-degrees apart.
16. A fiber optic connector, comprising: a connector inner housing
defining a key, a connector outer housing defining a first key slot
for positioning the connector outer housing in a first keyed
position relative to the connector inner housing with the key
engaging the first key slot and a second key slot for positioning
the connector outer housing in a second keyed position relative to
the connector inner housing with the key engaging the second key
slot; and a ferrule assembly disposed within the connector outer
housing and comprising an optical fiber ferrule defining an end
face and a ferrule holder.
17. The fiber optic connector according to claim 16, wherein the
connector is a duplex connector comprising a pair of
angled-physical-contact (AMC) ferrules and wherein the end faces of
the ferrules are aligned substantially coplanar in the first keyed
position for simultaneous polishing, and wherein the end faces of
the ferrules are aligned substantially parallel but not coplanar
for mating in the second keyed position.
18. The fiber optic connector according to claim 16, further
comprising a biasing element that engages a rear portion of the
ferrule assembly to urge the ferrule outwardly from the fiber optic
connector relative to the connector outer housing.
19. The fiber optic connector according to claim 16, further
comprising a plug housing defining an internal cavity opening
through opposed first and second ends for receiving the connector
inner housing, the connector outer housing and the ferrule
assembly, a flexible sealing boot, a coupling nut, a crimp body and
a crimp band.
20. The fiber optic connector according to claim 16, wherein the
connector outer housing is positionable between the first keyed
position and the second keyed position by pulling the connector
outer housing away from the connector inner housing, rotating the
connector outer housing relative to the connector inner housing
between the first keyed position and the second keyed position,
pushing the connector outer housing back towards the connector
inner housing, and engaging the key in one of the first key slot
and the second key slot.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates generally to fiber optic
connectors, and more specifically, to a duplex fiber optic
connector having positionable ferrules that allow the ferrules to
be rotated between a first keyed position for simultaneous coplanar
end face polishing, and a second keyed position for mating with a
receptacle, optical device or another connector of complimentary
ferrule configuration with proper end face contact.
[0003] 2. Technical Background
[0004] A variety of optical connectors have been developed to
facilitate the interconnection of optical fibers with other optical
fibers, optical devices or the like. In this regard, a number of
simplex, duplex and multi-fiber connectors including standard
ferrules, such as SC, LC, FC, MU, MT and MTP, have been designed. A
common type of connector includes an angled-physical-contact (APC)
ferrule that is designed to make physical contact with another APC
ferrule during the process of interconnecting optical fibers (i.e.,
mating opposing fiber optic connectors). The end face of an APC
ferrule is disposed at a non-orthogonal angle, i.e., at an angle
other than 90-degrees relative to the longitudinal axis defined by
the ferrule. Typically, the end face of an APC ferrule is disposed
at about an 8-degree angle relative to a plane that extends
perpendicular to the longitudinal axis defined by the ferrule. In
order to interconnect a pair of APC ferrules, the ferrules are
positioned such that the angled end faces are complimentary to one
another, that is, the forwardmost portion of the end face of one
ferrule is preferably aligned with the rearward most portion of the
end face of the other ferrule. In order to facilitate the proper
alignment of the ferrules in this complimentary fashion, the
connectors are mated in a specific manner. In certain APC
connectors, a portion of the connector assembly includes a physical
key, indicator or marking that is disposed in a predetermined
relationship to the end face of the ferrule and is used to orient
the connector relative to a mating connector.
[0005] APC ferrules may be preferred over physical-contact (PC)
ferrules, as well as ultra-physical-contact (UPC) ferrules, because
the angled end face of an APC ferrule advantageously reduces
undesirable reflections of optical signals at the interface between
the mating optical fibers, thereby decreasing losses and
correspondingly increasing signal transmission. Conventional APC
ferrules typically require that the amount of material removed from
the ferrule to define the angled end face be precisely controlled
so as to form the proper angled surface. In this regard, the
removal of either too much or too little material during the
process of polishing the end faces typically results in a
misalignment of mating ferrules, which decreases signal
transmission.
[0006] In conventional, industry standard LC or SC APC duplex
connectors, the two ferrules are typically aligned parallel
(side-by-side) such that the two end faces are not coplanar. This
orientation is needed in order to mate the duplex connector with an
industry standard connector having the same complimentary
orientation. By aligning the ferrules side-by-side, with the
ferrule end faces in different planes, it is not possible to
simultaneously polish the two ferrule end faces in the same plane
using conventional apparatus and processes. When assembling a
hardened duplex fiber optic connector using conventional LC or SC
APC ferrules, the design of the hardened connector does not allow
the ferrules to be separated and their end faces oriented into the
same plane for simultaneous polishing. By polishing the end faces
individually, one end face may be polished differently than the
other, thus resulting in connector-to-connector mating with
improper end face contact and resulting signal loss. Accordingly,
what is needed is a duplex hardened connector that allows the
ferrules and their respective end faces to be aligned relative to
one another for coplanar polishing, and thereafter moved to a
mating position.
[0007] In particular, a new approach is needed for a hardened
duplex fiber optic connector that allows the ferrules to be rotated
such that the end faces may be positioned in the same plane for
simultaneous coplanar polishing. Thus, a multi-position ferrule or
ferrule holder is needed that allows each ferrule to be rotated
between a first position in which the end faces of the ferrules are
coplanar for polishing, and a second position that properly aligns
the end faces for connector-to-connector mating with a
corresponding duplex connector of like ferrule configuration. The
first keyed ferrule position preferably allows both ferrule end
faces to be polished at the same time using conventional apparatus
and processes. Once the polish is complete, the ferrules are
rotated to the second keyed position for connector mating.
SUMMARY OF THE INVENTION
[0008] One aspect of the invention is a duplex fiber optic
connector including a first single fiber ferrule and a second
single fiber ferrule arranged side-by-side, wherein the first and
the second single fiber ferrules may be independently rotated
between a first keyed position and a second keyed position. The
first keyed position properly aligns the end face of the first
ferrule and the end face of the second ferrule substantially in the
same plane for simultaneous coplanar end face polishing using
conventional polishing apparatus and processes. The second keyed
position properly aligns the end face of the first ferrule and the
end face of the second ferrule for mating with a receptacle,
connector or optical device of like ferrule type in which the end
faces of the ferrules are not coplanar. The second keyed position
may also be used to align the end face of the first ferrule and the
end face of the second ferrule with a connector of like ferrule
configuration and with proper end face contact.
[0009] In another aspect, the present invention provides a fiber
optic connector in which each ferrule holder may be rotated between
a first keyed position for end face polishing, and a second keyed
position for mating with a receptacle, optical device or another
connector of like ferrule type with proper end face contact. The
keyed ferrule holder design may be used with any known simplex,
duplex or multi-fiber connector in which it is desired to
independently position or rotate each ferrule of the connector. The
first keyed position may be used to arrange the end faces of the
ferrules in a common plane for simultaneous end face polishing.
Polishing may be performed using conventional polishing apparatus
and processes. The second keyed position may be used to
independently arrange the alignment of the end face of each ferrule
in order to properly mate the connector with a receptacle, optical
device or another connector having a predetermined ferrule
arrangement, such as an industry standard connector of like ferrule
type.
[0010] In yet another aspect, the present invention provides a
fiber optic connector assembly including one or more keyed ferrule
holders that may be rotated between a first keyed position for end
face polishing and a second keyed position for mating with a
receptacle, optical device or another connector. In one particular
embodiment, the fiber optic connector is a duplex connector
including a first APC ferrule and a second APC ferrule. In an
exemplary embodiment, the duplex connector includes a plug housing
defining an internal cavity opening through opposed first and
second ends, a section of heat shrinkable tubing, a flexible boot,
a coupling nut, a protective/pulling cap assembly, a crimp body, a
crimp band, an connector inner housing, an connector outer housing
and one or more ferrules having a keyed ferrule holder. In a
specific embodiment, the ferrules are APC ferrules. In a further
embodiment, the connector assembly includes a biasing member that
operably engages and biases the respective ferrule toward the
mating ferrule during connector mating. To mate the fiber optic
connector with a like fiber optic connector or a receptacle
including a like ferrule arrangement, the externally threaded
coupling nut of the connector assembly is received, for example,
within an internally threaded receptacle, an internally threaded
coupling nut of another connector or an internally threaded
alignment sleeve.
[0011] In yet another aspect, the present invention provides a
fiber optic connector assembly including one or more keyed ferrule
holders that may be rotated between a first keyed position for end
face polishing and a second keyed position for mating with a
receptacle, device or other connector. In one particular
embodiment, the fiber optic connector is a duplex connector
including a first APC ferrule and a second APC ferrule. The duplex
connector includes a connector housing defining an internal cavity
opening through opposed first and second ends, a section of heat
shrinkable tubing, a flexible boot, a coupling nut, a
protective/pulling cap assembly, a crimp body, a crimp band, an
connector inner housing, an connector outer housing, one or more
ferrules having a keyed ferrule holder, and a biasing member that
operably engages a respective ferrule. The mating position of the
ferrules may be reconfigured for polishing by pushing the ferrule
inwards, clearing a key and rotating the ferrule holder to an
alternate key slot position. In a particular embodiment in which
the ferrule is an APC ferrule, the first and second key slots may
be located about 90-degrees apart.
[0012] Additional features and advantages of the invention will be
set forth in the following detailed description, and in part will
be readily apparent to those skilled in the art from that
description or recognized by practicing the invention as described
herein, including the accompanying drawings and the appended
claims.
[0013] It is to be understood that both the foregoing general
description and the following detailed description present
exemplary embodiments of the invention, and are intended to provide
an overview or framework for understanding the nature and character
of the invention as it is claimed. The accompanying drawings are
included to provide a further understanding of the invention, and
are incorporated into and constitute a part of this specification.
The drawings illustrate various embodiments of the invention, and
together with the detailed description, serve to explain the
principles and operations thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a perspective view of a duplex fiber optic
connector including multi-position ferrule holders that may be
rotated to facilitate simultaneous and coplanar ferrule end face
polishing, shown with the protective dust cap of the connector
removed;
[0015] FIG. 2 is a perspective view of the duplex fiber optic
connector of FIG. 1 shown disassembled;
[0016] FIG. 3A is an enlarged perspective view of a portion of the
duplex fiber optic connector of FIG. 1 including two SC ferrules
whose end faces are positioned in a first substantially coplanar
position for simultaneous polishing;
[0017] FIG. 3B is an enlarged perspective view of a portion of the
duplex fiber optic connector of FIG. 1 including two SC ferrules
whose end faces are positioned in a second non-coplanar position
for mating;
[0018] FIG. 4 is a perspective view of the duplex fiber optic
connector of FIG. 3 shown with the crimp band and one-half of the
crimp body removed for purposes of clarity;
[0019] FIG. 5A is a schematic side view of a keyed ferrule holder
and the end faces of two APC ferrules of a duplex fiber optic
connector shown in a first keyed position to facilitate
simultaneous coplanar end face polishing;
[0020] FIG. 5B is a schematic side view of the keyed ferrule holder
and the end faces of the two APC ferrules of FIG. 5A shown
positioned in a second keyed position for optical connection with a
corresponding pair of ferrules of a mating receptacle, optical
device or another connector;
[0021] FIG. 6A is a schematic side view of a positionable ferrule
holder including a biasing member for allowing the ferrule to float
and to be rotated between a first keyed position and a second-keyed
position; and
[0022] FIG. 6B is a schematic top view of the positionable ferrule
holder illustrating the first keyed position for ferrule polishing
and the second keyed position for mating.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0023] Reference will now be made in detail to the present
preferred embodiments of the invention, examples of which are
illustrated in the accompanying drawings. Whenever possible, the
same reference numerals will be used throughout the drawings to
refer to the same or like parts. An exemplary embodiment of a
duplex fiber optic connector according to the invention is shown in
FIG. 1 with the fiber optic connector designated generally
throughout the various figures by reference numeral 20.
[0024] Referring now specifically to the accompanying drawings,
FIGS. 1-6 show a duplex fiber optic connector 20 including two
individual SC APC connectors mounted side-by-side on a duplex
cable. As is known in the art, SC connectors include a single
optical fiber in a standard-sized (2.5 mm diameter) ceramic
ferrule. As is also known in the art, LC connectors hold a single
optical fiber in a smaller (1.25 mm diameter) ceramic ferrule and
may be used in environments in which a small form factor connector
is needed. A duplex fiber optic connector having a positionable
ferrule holder in accordance with the present invention typically
utilizes SC or LC ferrules based on their advantageous size. While
a duplex connector including two SC APC connectors is shown, the
present invention is not intended to be limited to that specific
connector type or number of connectors. In addition, multifiber and
non-APC connectors may benefit from the principles and advantages
of the present invention.
[0025] Referring specifically to FIG. 1, a duplex fiber optic
connector 20 including a first single fiber ferrule 22 and a second
single fiber ferrule 24 arranged side-by-side is shown. The first
and the second single fiber ferrules 22, 24 may be independently
rotated between a first keyed position and a second keyed position.
The first keyed position properly aligns the end face 26 of the
first ferrule 22 and the end face 28 of the second ferrule 24
substantially in the same plane for simultaneous coplanar end face
polishing. As is known in the art, end face polishing may be
performed using conventional polishing apparatus and processes. The
second keyed position properly aligns the end face 26 of the first
ferrule 22 and the end face 28 of the second ferrule 24 for mating
with a receptacle, optical device or another connector of like
ferrule type in which the end faces of the ferrules are not
coplanar. The second keyed position may also be used to align the
end face 26 of the first ferrule 22 and the end face 28 of the
second ferrule 24 with a connector having an industry standard
configuration.
[0026] The duplex fiber optic connector 20 is shown with the
combination protective dust/pulling cap 30 removed. The protective
dust/pulling cap 30 is secured to a portion of the connector 20 by
a flexible lanyard 32. A threaded coupling nut 34 on the connector
20 may be operable for securing the connector 20 to a receptacle
(not shown), optical device (not shown) or another connector (not
shown) upon engagement and may also be used to secure the
dust/pulling cap 30 on the connector 20 during shipping and
deployment of the duplex cable 36. The coupling nut 34 may be
replaced with a bayonet or push-pull mechanism to secure the
connector 20 within the receptacle, optical device or another
connector. Alternatively, a spring clip or similar device may be
added to engage the connector 20 with the receptacle, optical
device or another connector to secure them together. Sealing may be
removed or relaxed based upon the extent of the adverse environment
to which the connector assembly is exposed. Although not shown, the
dust/pulling cap 30 may define a pulling loop at its forward end.
In preferred embodiments, the pulling loop should be able to
withstand cable-pulling forces up to about 600 lbs. The fiber optic
connector 20 and dust/pulling cap 30 provide a fully sealed design
that prevents moisture and contamination from reaching the ferrule
end faces 26, 28. In all embodiments, elastic seals, grommets or
O-rings may be used to provide static seals, and their position
combined with relief features to minimize vacuum build-up during
unplugging the connector or pressure build-up when mating the plug
with a receptacle, optical device or another connector. Generally
speaking, most of the components of the connector 20 are formed
from a suitable polymer. Preferably, the polymer is a UV stabilized
polymer such as ULTEM 2210 available from GE Plastics. However,
other suitable materials may also be used. For example, stainless
steel or any other suitable metal may be used for various
components without departing from the spirit of the invention.
[0027] In the embodiments shown and described herein, different
types of fiber optic cables may function as the connector cable,
also referred to herein as the "drop cable", such as, but not
limited to, monotube, loose tube, central tube, ribbon, flat
dielectric and the like. However, in the exemplary embodiments
shown, the drop cable is a duplex cable 36 and comprises a cable
jacket 38 with a strength component and an optical transmission
component disposed within the cable jacket. In one embodiment, the
strength component comprises two glass-reinforced plastic (GRP)
strength components (indicated at reference numeral 40 in FIG. 4),
and the optical transmission component (indicated at reference
numeral 42 in FIG. 4) comprises an optical waveguide disposed
within a central tube, such as a buffer tube. The drop cable may
also comprise strength members that provide additional tensile
strength. It is understood that other cable types may be used in
conjunction with the present invention. Moreover, various optical
connectors may be used with different fiber optic cables in
accordance with the principles of the present invention, thereby
resulting in numerous cable/connector combinations. The cable 36 is
preferably designed to provide stable performance over a wide range
of temperatures and to be compatible with any telecommunications
grade optical fiber. As used herein, the term "optical fiber" is
intended to include all types of single mode and multi-mode light
waveguides, including one or more bare optical fibers, coated
optical fibers, loose-tube optical fibers, tight-buffered optical
fibers, ribbonized optical fibers or any other expedient for
transmitting light signals.
[0028] At the end of the connector 20 opposite the dust/pulling cap
30, a pre-formed, elastomeric boot 44 covers the rear of the
connector 20 and generally inhibits kinking while providing bending
strain relief to the cable 36 near the connector 20. Disposed
immediately underneath the elastomeric boot 44 is a section of heat
shrinkable tubing 46 that is secured over a portion of the cable 36
and a portion of a plug housing 48. The heat shrinkable tubing 46
protects the rear of the connector 20 from the environment and
provides a sealing function. The boot 44 may be pre-manufactured
(e.g., molded) and assembled onto cable 36, or may be overmolded
using a technology available from Corning Cable Systems LLC of
Hickory, N.C. Further, the heat shrinkable tubing 46 may be used to
fulfill the same purpose as the boot 44 when aesthetics are less
important and bend characteristics less stringent.
[0029] The plug housing 48 defines an internal cavity opening
through opposed first 50 and second 52 ends. The plug housing 48
generally protects the ferrules 22, 24 and in preferred embodiments
also aligns and keys engagement of the connector 20 with the mating
receptacle, alignment sleeve, optical device or another connector.
In the embodiment shown, the first end 50 of the plug housing 48
defines alignment and keying features 54 that permit mating in only
one orientation and also provide access to the end faces of the
ferrules 22, 24 from the sides of the connector 20. In preferred
embodiments, this orientation may be marked on the features 54
using alignment indicia so that a less skilled field technician can
readily mate the connector 20 with the receptacle, alignment
sleeve, optical device or other connector. Any suitable indicia may
be used. After alignment, the field technician engages the coupling
nut 34 to secure the connector 20 to the mating component. The plug
housing 48 may further define a shoulder 56 that serves as a
mechanical stop for a conventional elastomeric O-ring (not shown),
as well as the coupling nut 34. The O-ring provides an
environmental seal when the coupling nut 34 engages the mating
component. Preferably, the coupling nut 34 has an interior
passageway sized to loosely fit over the second end 52 of the plug
housing 48 so that the coupling nut 34 rotates without any
significant resistance about the plug housing 48.
[0030] Referring now to FIG. 2, the duplex fiber optic connector of
FIG. 1 is shown disassembled. A portion of the cable sheath 38 is
removed to expose the underlying optical component 42. The optical
component 42 of the cable 36 is received within two substantially
similar halves of a crimp body 58 that are secured together around
the optical component 42 by a crimp band 60. As will be shown in
more detail in FIG. 4, a connector inner housing is also received
within the crimp body 58. Any exposed portion 72 of the cable 36
between the cut sheath 38 and the crimp body 58 is covered by the
plug housing 48 and sealed by the heat shrinkable tubing 46. As is
well understood by those of ordinary skill in the art, the plug
housing 48, the heat shrinkable tubing 46, the crimp band 60, the
flexible boot 44 and the coupling nut 34 are threaded onto the
cable 36 before the two halves of the crimp body 58 are brought
together. The plug housing 48 defines an internal stop (not shown)
that properly positions the crimp body 58 relative to the plug
housing and prevents it from being rotated with respect to the
crimp body 58 or being pulled off the cable assembly beyond the
crimp body 58.
[0031] Referring now to FIGS. 3A and 3B, the crimp body 58 and
connector housing portion of the duplex fiber optic connector of
FIG. 1 are shown enlarged and with the crimp band 60 removed in
order to illustrate the connector outer housings 62, 64 and first
and second keyed positions of the outer housings 62, 64. In FIGS.
3A and 3B, the end faces of the ferrules 22, 24 are shown at an
exaggerated angle for illustrative purposes only. In preferred
embodiments, the end face of the APC ferrules 22, 24 are disposed
at about an 8-degree angle relative to a plane that extends
perpendicular to the longitudinal axis defined by the ferrule.
Referring specifically to FIG. 3A, the connector outer housings 62,
64 and ferrules 22, 24 are positioned in a first, substantially
coplanar orientation for polishing. The end faces 26, 28 are
positioned so that they may be polished simultaneously using
conventional apparatus and processes as is known in the art.
Referring specifically to FIG. 3B, the connector outer housings 62,
64 and the ferrules 22, 24 are positioned in a second, non-coplanar
position for mating with an opposing connector. The connector
mating position aligns the ferrule end faces 26, 28 in an industry
standard configuration in which each ferrule 22, 24 is rotated in
the same clockwise direction approximately 90-degrees from its
polishing position. In an alternative embodiment, each ferrule 22,
24 may be rotated about 90-degrees in a counter-clockwise direction
to achieve the same industry standard configuration. Key slots are
shown at reference number 66, and the details of rotating the
connector outer housings 62, 64, and in turn the ferrule end faces
26, 28, between their first and second positions is described below
and shown in FIG. 4.
[0032] Referring to FIG. 4, the portion of the duplex fiber optic
connector of FIGS. 3A and 3B is shown with the crimp 60 band and
one-half of the crimp body 58 removed for purposes of clarity. The
crimp body 58 defines on its inner surface a recess 68 for
receiving the optical transmission component 42 and a pair of
recesses 70 for receiving the pair of GRP strength components 40.
The optical transmission component 42 and the GRP strength
components 40 are terminated and are held between the two halves of
the crimp body 58. The two halves of the crimp body 58 are then
secured together by the crimp band 60. The crimp band 60 provides
strain relief for the cable 36 through the GRP strength components
40 and is preferably made from brass, but other suitable deformable
materials may be used. In the embodiment shown, the cable jacket 38
is cut and stripped back and does not enter the crimp body 58. In
an alternative embodiment, a portion of the cable jacket 38 may
also be received within a recess defined by the crimp body 58 to
provide strain relief to the cable jacket instead of or in addition
to the strain relief provided by the GRP strength components 40 and
the crimp body.
[0033] As is well known to one of ordinary skill in the relevant
art, the two optical fibers 74 of the duplex cable 36 terminate
within longitudinally extending optical fiber bores of the two
single fiber ferrules 22, 24. The connector outer housings 62, 64
are not secured by the crimp body 58, but are free to be pulled
away from the crimp body 58, rotated to the desired, keyed position
and pushed back into place against the crimp body 58. The connector
inner housings 76 are received within recesses 78 defined by the
crimp body halves 58 and are held between the two halves. The
ferrules 22, 24 are rotated between their first and second keyed
positions by pulling the connector outer housings 62, 64 out away
from the crimp body 58 sufficiently to clear the corresponding
connector inner housing 76, and rotating the outer housings to
either their first or second keyed position. Once positioned, the
connector outer housings 62, 64 are then pressed back in towards
the crimp body 58 and the key slot 66 formed in the connector outer
housing receives the key defined by the connector inner housing 76.
As shown, the first and second keyed positions are separated by and
are achieved by rotating the connector outer housings 62, 64 about
90-degrees in either the clockwise or counter-clockwise direction.
Movement of the outer housings 62, 64 relative to the crimp body 58
is represented by reference numbers 80 and 82 in FIG. 4. In an
alternative embodiment, the entire connector housing assembly,
including both the connector inner housings 76 and the connector
outer housings 62, 64 may be rotated by removing one half of the
crimp body 58, rotating the connector housing assembly to the
desired position, replacing the one half of the crimp body 58 that
was previously removed and installing the crimp band 60.
[0034] The connector outer housings 62, 64 define key slots 66 on
two adjacent sides. The underlying connector inner housings 76
define a key (not shown) that is received within the key slot 66 of
the connector outer housings 62, 64. As shown in FIG. 4, the duplex
fiber optic connector 20 includes a first single fiber ferrule 22
and a second single fiber ferrule 24 arranged side-by-side, wherein
the first and the second single-fiber ferrules 22, 24 may be
independently rotated between a first keyed position and a second
keyed position. As shown, the first ferrule end face 26 is aligned
in the mating position, and the second ferrule end face 28 is
rotated about 90-degrees relative to the first ferrule end face 26
to the polishing position. Each connector outer housing 62, 64 may
be moved between the polishing and mating positions by a rotation
of about 90-degrees around the longitudinal axis defined by the
ferrules 22, 24.
[0035] Referring to FIGS. 5A-6B, in another embodiment, the present
invention provides a fiber optic connector assembly 20 including
one or more keyed ferrule holders 84 that may be rotated between a
first keyed position for end face polishing and a second keyed
position for mating with a receptacle, optical device or another
connector. In one particular embodiment, the fiber optic connector
is a duplex fiber optic connector including a first APC ferrule 22
and a second APC ferrule 24. In an exemplary embodiment, the duplex
connector includes a connector housing defining an internal cavity
opening through opposed first and second ends, a section of heat
shrinkable tubing, a flexible boot, a coupling nut, a protective
dust/pulling cap assembly, a crimp body, a crimp band, and a pair
of keyed ferrule holders 84 for securing the ferrules 22, 24. In a
further embodiment, the connector assembly 20 includes a biasing
member that operably engages and biases the respective ferrule 22,
24 toward the mating ferrule during connector mating. In a still
further embodiment, the connector assembly 20 includes a second
biasing member that operably engages the ferrule 22, 24 during
movement between the first and second keyed positions.
[0036] Referring specifically to FIG. 5A, the end faces 26, 28 of
the two APC ferrules 22, 24 of a duplex fiber optic connector are
shown in a first keyed position to facilitate simultaneous coplanar
end face polishing. In the embodiment shown, the key slots 66 of
each ferrule holder 84 are positioned about 90-degrees apart from
each other around the circumference of the ferrule holder.
Referring specifically to FIG. 5B, the keyed ferrule holders 84 are
rotated 90-degrees in a counter-clockwise direction to the second
keyed position in order to align the end faces 26, 28 of the two
APC ferrules of the duplex fiber optic connector for optical
connection with a corresponding pair of ferrules of a mating
receptacle, optical device or another connector. Portions of the
ferrule holder 84 are removed to form the key slots 66. As
described in more detail below, portions equaling the entire height
of the ferrule holder 84 are removed in order to permit the ferrule
22, 24 to be depressed into its respective connector outer housing
62, 64, compress a biasing spring and clear a key defined by the
connector outer housing 62, 64 so that the ferrule holder 84 can be
rotated to its appropriate key position and released, thus allowing
the biasing spring to extend and press the ferrule holder 84 back
into place. In an alternative embodiment, only a portion of the
height of the ferrule holder 84 is removed in order to define a key
slot 66, and a key defined by the connector outer housing 62, 64 is
received within the corresponding key slot. The ferrule holder 84
may be keyed so that it may be rotated within its respective
connector outer housing 62, 64, or may be keyed so that it is fixed
with respect to orientation within its respective connector outer
housing such that the connector outer housing and ferrule holder
assembly may be rotated together as one assembly. Although fixed in
orientation, a biasing member, such as a spring, may operably
engage the ferrule 22 and a component of the connector outer
housing 62, 64 to urge the ferrule 22 toward the mating end of the
opposing connector. In any embodiment of the invention in which the
orientation of the ferrule 22 may be changed, the desired result is
that the end faces 26, 28 of the ferrules 22, 24 may be rotated
between various positions for a desired alignment of the end faces
of the one or more ferrules.
[0037] Referring to FIG. 6A, a schematic side view of a
positionable ferrule holder 84 including a biasing member 86 for
allowing the ferrule 22 to float and to be rotated between a first
keyed position and a second keyed position is shown. The ferrule
holder 84 is not fixed within the connector outer housing 62, but
is engaged by the biasing member 86. In one embodiment, the biasing
member 86 may operably engage the ferrule 22 and the connector
outer housing 62 to urge the ferrule 22 toward the mating end of
the opposing connector, and may also be used to reconfigure the
ferrule 22 by permitting the ferrule 22 to be pushed into the
connector outer housing 62, clear the key (indicated at reference
numeral 88 in FIG. 6B) and rotate the ferrule assembly to an
alternate key slot 66. In an alternative embodiment, the key may be
defined by the connector inner housing 76. In either embodiment,
the ferrule holder key positions are not used for loss
optimization, but for ferrule assembly positioning. Loss
suppression may be accomplished by means other than ferrule
assembly positioning.
[0038] Referring to FIG. 6B, a schematic top view of the
positionable ferrule holder 84 of FIG. 6B is shown illustrating a
first keyed position for ferrule polishing and a second keyed
position for connector mating. The first keyed position 90 is
positioned about 90-degrees (indicated at reference numeral 94)
from the second keyed position 92 around the circumference of the
ferrule holder 84. A 90-degree rotation of each of the one or more
ferrules about the longitudinal axis defined by the ferrule serves
to re-position the ferrule end faces between a coplanar position
for polishing, and once the polish is complete, a standard
configuration for connector mating. As stated above, the ferrule
holder 84 may be rotated to a polishing configuration from a
standard mating configuration by pushing the ferrule assembly into
the connector outer housing 62, clearing the key 88, and rotating
the ferrule holder to the appropriate key slot 66.
[0039] In further embodiments, the entire connector housing
assembly, any component thereof or the one or more ferrules
themselves may be rotated between a first keyed position for end
face polishing and a second keyed position for mating with a
receptacle, optical device or another connector. Thus, designs for
several types of connectors having rotatable ferrule assemblies may
be derived from the basic design shown and described herein. In all
embodiments, the polishing position aligns the end faces of the one
or more ferrules in a coplanar configuration for simultaneous
polishing, and the mating configuration aligns the end faces of the
ferrules for interconnection with other optical fibers, such as for
extending an all optical communications network to a subscriber
premises, such as a residence or business. Ferrule holders having
specific key slot shapes and connector components having specific
key shapes may be created for each type of ferrule. While certain
generic connector components may be used for all ferrule types,
crimp bodies and connector housing components may have specific
shapes to accommodate specific ferrules and cable types.
[0040] The embodiments described above provide advantages over
conventional connector assemblies. In contrast to conventional
hardened duplex fiber optic connectors that do not provide the
ability to move the ferrules, the connectors of the present
invention allow the ferrules to be independently positioned, thus
allowing simultaneous polishing using conventional apparatus and
processes. In addition, the keyed ferrule holders described herein
do not increase the overall package size of the connector, thus
allowing the connectors to be interconnected with conventional
receptacles. Further, the keying features of these connectors makes
them fully APC capable.
[0041] It will be apparent to those skilled in the art that various
modifications and variations can be made to the present invention
without departing from the spirit and scope of the invention. Thus,
it is intended that the present invention cover the modifications
and variations of this invention provided they come within the
scope of the appended claims and their equivalents.
* * * * *