US007150567B1
`
`United States Patent
`US 7,150,567 B1
`(10) Patent No.:
`(12)
`Luther et al.
`(45) Date of Patent:
`Dec. 19, 2006
`
`
`(54) FIBER OPTIC CONNECTOR HAVING
`KEYED FERRULE HOLDER
`
`6,955,479 BL* 10/2005 Erdman et al. we. 385/78
`2005/0117850 Al
`6/2005 Milette
`
`(75)
`
`Inventors: James P. Luther, Hickory, NC (US);
`Thomas Theuerkorn, Hickory, NC
`(US); Hleu V. Tran, Charlotte, NC
`(US)
`
`(73) Assignee: Corning Cable Systems LLC, Hickory,
`NC (US)
`Subject to any disclaimer, the term ofthis
`patent is extended or adjusted under 35
`
`(*) Notice:
`
`OTHER PUBLICATIONS
`Fiber Systems International Fiber Optics Solutions Product Sheet,
`TFOCA-II® 4-Channel Fiber Optic Connector, 2 sheets, 2003.
`STRATOSLightwave ™, Hybrid HMASeries, Jul. 16, 2002.
`INFOLITE Data Sheet.
`.
`.
`* cited by examiner
`S. Bernard
`(18)doormenteentorFinnteffrev
`oY
`ABenl,
`yy
`
`(21) Appl. No.: 11/139,734
`
`(22)
`
`Filed:
`
`May27, 2005
`
`(51)
`
`.
`.
`.
`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
`Int. Cl.
`first or the second key slot. The first key slot configures the
`(2006.01)
`G02B 6/36
`Connectorin a first keyed position for simultaneous, copla-
`(52) US. Che eeceeccccsecceeceeseeeeeeee 385/78; 385/60; 385/72
`har endface polishing of the ferrules, and the second keyed
`(58) Field of Classification Search... 385/55,
`position configures the connector for mating with a recep-
`385/60. 72. 78. 83. 84. 140: 285/260: 333/209.
`tacle, optical device or another connector. A fiber optic
`eee? ;
`; 439/607
`connector including a connector outer housing defining a
`See application file for complete search history.
`first key slot for positioning the connector housinginafirst
`(56)
`References Cited
`keyed position and a second key slot for positioning the
`connector housing in a second keyed position, a connector
`U.S. PATENT DOCUMENTS
`inner housing defining a key and a ferrule assembly includ-
`ing 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.
`
`6,206,579 BL
`6,234,683 Bl
`6,264,374 BL
`6,305,849 Bl
`6,357,929 Bl
`6,371,660 Bl
`6,579,014 Bl
`6,648,520 Bl
`6,678,448 Bl
`
`3/2001 Selfridge et al... 385/60
`5/2001 Waldron et al.
`.............. 385/78
`7/2001 Selfridge et al.
`............. 385/78
`10/2001 Roehrs et al.
`......
`ve 385/59
`3/2002 Roehrset al.
`......
`ve 385/59
`4/2002 Roehrset al.
`..
`wee 385/59
`6/2003 Melton et al.
`......
`.. 385/76
`11/2003 McDonald et al.
`we 385/78
`.
`1/2004 Moisel et al.
`........0.000. 385/101
`
`
`
`
`
`
`
`
`
`
`
`19 Claims, 6 Drawing Sheets
`
`Senko EX1029
`PGR2024-00037
`U.S. Patent No. 7,150,567
`
`Senko EX1029
`PGR2024-00037
`U.S. Patent No. 7,150,567
`
`

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`U.S. Patent
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`Dec. 19, 2006
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`U.S. Patent
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`Sheet 6 of 6
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`US 7,150,567 B1
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`FIG. 6A
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`US 7,150,567 B1
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`1
`FIBER OPTIC CONNECTOR HAVING
`KEYED FERRULE HOLDER
`
`BACKGROUND OF THE INVENTION
`
`2
`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.
`1. Field of the Invention
`Accordingly, what is needed is a duplex hardened connector
`that allows the ferrules and their respective end faces to be
`The present
`invention relates generally to fiber optic
`aligned relative to one another for coplanar polishing, and
`connectors, and more specifically, to a duplex fiber optic
`connector having positionable ferrules that allow the ferrules
`thereafter moved to a mating position.
`
`to be rotated betweenafirst keyed position for simultaneous In particular, a new approach is needed for a hardened
`coplanar end face polishing, and a second keyed position for
`duplex fiber optic connector that allows the ferrules to be
`mating with a receptacle, optical device or another connector
`rotated such that the end faces maybe positioned in the same
`of complimentary ferrule configuration with proper end face
`plane for simultaneous coplanar polishing. Thus, a multi-
`contact.
`position ferrule or ferrule holder is needed that allows each
`
`2. Technical Background ferrule to be rotated betweenafirst position in which the end
`A variety of optical connectors have been developed to
`faces ofthe ferrules are coplanar for polishing, and a second
`facilitate the interconnection of optical fibers with other
`position that properly aligns the end faces for connector-to-
`optical fibers, optical devices or the like. In this regard, a
`connector mating with a corresponding duplex connector of
`number of simplex, duplex and multi-fiber connectors
`like ferrule configuration. The first keyed ferrule position
`including standard ferrules, such as SC, LC, FC, MU, MT
`preferably allows both ferrule end faces to be polished at the
`and MTP, have been designed. A commontype of connector
`same time using conventional apparatus and processes.
`includes an angled-physical-contact (APC) ferrule that is
`Oncethe polish is complete, the ferrules are rotated to the
`designed to make physical contact with another APC ferrule
`second keyed position for connector mating.
`during the process of interconnecting optical fibers (1.e.,
`mating opposing fiber optic connectors). The end face of an
`APCferrule is disposed at a non-orthogonalangle,1.e., at an
`One aspect of the invention is a duplex fiber optic
`angle other than 90-degrees relative to the longitudinal axis
`connector includingafirst single fiber ferrule and a second
`defined by the ferrule. Typically, the end face of an APC
`single fiber ferrule arranged side-by-side, wherein the first
`ferrule is disposed at about an 8-degree angle relative to a
`and the second single fiber ferrules may be independently
`plane that extends perpendicular to the longitudinal axis
`rotated between a first keyed position and a second keyed
`defined bythe ferrule. In order to interconnect a pair of APC
`position. The first keyed position properly aligns the end
`ferrules, the ferrules are positioned such that the angled end
`face of the first ferrule and the end face of the secondferrule
`faces are complimentary to one another, that is, the forward-
`most 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.
`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 advanta-
`geously 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
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`define the angled end face be precisely controlled so as to
`form the proper angled surface. In this regard, the removal
`of either too muchortoo little material during the process of
`polishing the end faces typically results in a misalignment of
`mating ferrules, which decreases signal transmission.
`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 notallow the ferrules
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`SUMMARY OF THE INVENTION
`
`substantially in the same plane for simultaneous coplanar
`end face polishing using conventional polishing apparatus
`and processes. The second keyed position properly aligns
`the endface 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 secondferrule with a connectorof like ferrule
`
`configuration and with proper end face contact.
`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 connectoroflike ferrule type with proper
`end face contact. The keyed ferrule holder design may be
`used with any known simplex, duplex or multi-fiber con-
`nector 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
`commonplane for simultaneous end face polishing. Polish-
`ing may be performed using conventional polishing appa-
`ratus 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.
`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
`
`

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`US 7,150,567 B1
`
`3
`4
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`connectoris a duplex connector includingafirst APC ferrule FIG. 3A is an enlarged perspective view of a portion of the
`and a second APCferrule. In an exemplary embodiment, the
`duplex fiber optic connector of FIG. 1 including two SC
`duplex connector includes a plug housing defining an inter-
`ferrules whose end faces are positioned in a first substan-
`nal cavity opening through opposedfirst and second ends, a
`tially coplanar position for simultaneous polishing;
`section of heat shrinkable tubing,a flexible boot, a coupling
`FIG.3B is an enlarged perspective view of a portion of the
`nut, a protective/pulling cap assembly, a crimp body, a crimp
`duplex fiber optic connector of FIG. 1 including two SC
`band, an connector inner housing, an connector outer hous-
`ferrules whose end faces are positioned in a second non-
`ing and one or moreferrules having a keyed ferrule holder.
`coplanar position for mating;
`In a specific embodiment, the ferrules are APC ferrules. In
`FIG. 4 is a perspective view of the duplex fiber optic
`a further embodiment, the connector assembly includes a
`connector of FIG. 3 shown with the crimp band and one-half
`biasing memberthat operably engages andbiases the respec-
`of the crimp body removed for purposesofclarity;
`tive ferrule toward the mating ferrule during connector
`FIG. 5A is a schematic side view of a keyed ferrule holder
`mating. To mate the fiber optic connector with a like fiber
`and the end faces of two APCferrules of a duplexfiber optic
`optic connector or a receptacle including a like ferrule
`connector shown in a first keyed position to facilitate
`arrangement, the externally threaded coupling nut of the
`simultaneous coplanar end face polishing;
`connector assembly is received, for example, within an
`FIG. 5B is a schematic side view of the keyed ferrule
`holder and the end faces of the two APCferrules of FIG. 5A
`internally threaded receptacle, an internally threaded cou-
`pling nut of another connector or an internally threaded
`alignment sleeve.
`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
`APCferrule. 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 assem-
`bly, 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 androtating the ferrule holder
`to an alternate key slot position. In a particular embodiment
`in whichthe ferrule is an APC ferrule, the first and second
`key slots may be located about 90-degrees apart.
`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 appendedclaims.
`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.
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`BRIEF DESCRIPTION OF THE DRAWINGS
`
`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 coplanarferrule end
`face polishing, shown with the protective dust cap of the
`connector removed;
`FIG. 2 is a perspective view of the duplex fiber optic
`connector of FIG. 1 shown disassembled;
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`shown positioned in a second keyed position for optical
`connection with a corresponding pair offerrules of a mating
`receptacle, optical device or another connector;
`FIG. 6A is a schematic side view ofa positionable ferrule
`holder including a biasing member for allowing the ferrule
`to float and to be rotated betweena first keyed position and
`a second-keyed position; and
`FIG.6B is a schematic top view ofthe positionable ferrule
`holder illustrating the first keyed position for ferrule polish-
`ing and the second keyed position for mating.
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENTS
`
`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 through-
`out 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.
`Referring now specifically to the accompanying draw-
`ings, FIGS. 1-6 show a duplex fiber optic connector 20
`including two individual SC APC connectors mountedside-
`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 advanta-
`geous 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.
`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. Thefirst and the second single fiber ferrules 22, 24
`maybe independently rotated betweena first keyed position
`and a second keyed position. The first keyed position
`properly aligns the end face 26 ofthefirst ferrule 22 and the
`end face 28 of the secondferrule 24 substantially in the same
`plane for simultaneous coplanar end face polishing. As is
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`US 7,150,567 B1
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`5
`knownin 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 thefirst ferrule 22 and the end face
`28 of the second ferrule 24 with a connector having an
`industry standard configuration.
`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 mayalso be usedto secure the dust/pulling cap 30 on the
`connector 20 during shipping and deploymentof 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 loopat its forward end. In preferred embodi-
`ments, the pulling loop should be able to withstand cable-
`pulling forces up to about 600 Ibs. 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 providestatic seals, and
`their position combined with relief features to minimize
`vacuum build-up during unplugging the connector or pres-
`sure 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 stabi-
`lized 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.
`In the embodiments shown anddescribed 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 componentdisposed within the cable
`jacket. In one embodiment, the strength component com-
`prises two glass-reinforced plastic (GRP) strength compo-
`nents (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 membersthat 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
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`designedto provide stable performance over a wide range of
`temperatures and to be compatible with any telecommuni-
`cations 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 opticalfibers,
`tight-buffered optical fibers, ribbonized optical fibers or any
`other expedient for transmitting light signals.
`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 pro-
`viding bendingstrain relief to the cable 36 near the connec-
`tor 20. Disposed immediately underneath the elastomeric
`boot 44 is a section of heat shrinkable tubing 46 that is
`secured overa 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 maybe usedto fulfill the same purpose
`as the boot 44 when aesthetics are less important and bend
`characteristics less stringent.
`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 embodi-
`ment 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 alignmentindicia so that a less skilled
`field technician can readily mate the connector 20 with the
`receptacle, alignment sleeve, optical device or other con-
`nector. 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
`mayfurther 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 envi-
`ronmental seal when the coupling nut 34 engages the mating
`component. Preferably, the coupling nut 34 has an interior
`passagewaysizedto 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.
`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 com-
`ponent 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 band60, 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 58relative to the plug
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`US 7,150,567 B1
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`20
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`connector inner housing 76, and rotating the outer housings
`to either their first or second keyed position. Once posi-
`tioned, 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-clock-
`wise 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 hous-
`ings 62, 64 mayberotated by removing onehalf 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 removedandinstalling the crimp band
`60.
`
`7
`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.
`Referring now to FIGS. 3A and 3B, the crimp body 58 and
`connector housing portion of the duplex fiber optic connec-
`tor of FIG. 1 are shown enlarged and with the crimp band 60
`removed in orderto 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 connector outer housings 62, 64 define key slots 66
`the art. Referring specifically to FIG. 3B, the connector outer
`on two adjacent sides. The underlying connector inner
`housings 62, 64 and the ferrules 22, 24 are positioned in a
`housings 76 define a key (not shown) that is received within
`second, non-coplanar position for mating with an opposing
`the key slot 66 of the connector outer housings 62, 64. As
`connector. The connector mating position aligns the ferrule
`shown in FIG. 4,
`the duplex fiber optic connector 20
`end faces 26, 28 in an industry standard configuration in
`25
`which each ferrule 22, 24 is rotated in the same clockwise
`includesafirst single fiber ferrule 22 and a second single
`direction approximately 90-degrees from its polishing posi-
`fiber ferrule 24 arranged side-by-side, wherein the first and
`tion. In an alternative embodiment, each ferrule 22, 24 may
`the second single-fiber ferrules 22, 24 may be independently
`be rotated about 90-degress in a counter-clockwise direction
`rotated between a first keyed position and a second keyed
`to achieve the same industry standard configuration. Key
`position. As shown,the first ferrule end face 26 is aligned in
`slots are shown at reference number 66, and the details of
`the mating position, and the second ferrule end face 28 is
`rotating the connector outer housings 62, 64, and in turn the
`rotated about 90-degreesrelative to the first ferrule end face
`ferrule end faces 26, 28, between their first and second
`26 to the polishing position. Each connector outer housing
`positions is described below and shownin FIG.4.
`62, 64 may be moved between the polishing and mating
`Referring to FIG.4, the portion of the duplex fiber optic
`positions by a rotation of about 90-degrees around the
`connector of FIGS. 3A and 3B is shown with the crimp 60
`longitudinal axis defined by the ferrules 22, 24.
`band and one-half of the crimp body 58 removed for
`Referring to FIGS. 5A—6B, in another embodiment, the
`purposes ofclarity. The crimp body 58 defines on its inner
`present invention provides a fiber optic connector assembly
`surface a recess 68 for receiving the optical transmission
`20 including one or more keyed ferrule holders 84 that may
`component42 and a pair of recesses 70 for receiving the pair
`be rotated between a first keyed position for end face
`of GRP strength components 40. The optical transmission
`polishing and a second keyed position for mating with a
`component 42 and the GRP strength components 40 are
`receptacle, optical device or another connector.
`In one
`terminated andare held between the two halves of the crimp
`particular embodiment, the fiber optic connector is a duplex
`body 58. The two halves of the crimp body 58 are then
`fiber optic connector including a first APC ferrule 22 and a
`secured together by the crimp band 60. The crimp band 60
`second APC ferrule 24. In an exemplary embodiment, the
`provides strain relief for the cable 36 through the GRP
`duplex connector includes a connector housing defining an
`strength components 40 and is preferably made from brass,
`internal cavity opening through opposed first and second
`but other suitable deformable materials may be used. In the
`ends, a section of heat shrinkable tubing, a flexible boot, a
`embodiment shown, the cable jacket 38 is cut and stripped
`coupling nut, a protective dust/pulling cap assembly, a crimp
`back and does not enter the crimp body 58. In an alternative
`body, a crimp band, and a pair of keyed ferrule holders 84
`embodiment, a portion of the cable jacket 38 may also be
`for securing the ferrules 22, 24. In a further embodiment, the
`received within a recess defined by the crimp body 58 to
`connector assembly 20 includes a biasing member that
`provide strain relief to the cable jacket instead of or in
`operably engages and biases the respective ferrule 22, 24
`
`addition to the strain relief provided by the GRPstrength toward the mating ferrule during connector mating. Inastill
`components 40 and the crimp body.
`further embodiment, the connector assembly 20 includes a
`Asis well known to one of ordinary skill in the relevant
`second biasing memberthat operably engagesthe ferrule 22,
`art, the two optical fibers 74 of the duplex cable 36 terminate
`24 during movement between the first and second keyed
`within longitudinally extending opticalfiber bores of the two
`positions.
`single fiber ferrules 22, 24. The connector outer housings 62,
`Referring specifically to FIG. 5A, the end faces 26, 28 of
`64 are not secured by the crimp body 58, but are free to be
`the two APC ferrules 22, 24 of a duplex fiber optic connector
`60
`
`pulled away from the crimp body 58, rotated to the desired, are showninafirst keyed positionto facilitate simultaneous
`keyed position and pushed back into place against the crimp
`coplanar e