US007628545B2
`
`US 7,628,545 B2
`(10) Patent No.:
`a2) United States Patent
`Codyet al.
`(45) Date of Patent:
`Dec. 8, 2009
`
`
`(54) FIBER OPTIC PLUG ASSEMBLY WITH BOOT
`AND CRIMP BAND
`
`(75)
`
`Inventors: Joseph Todd Cody, Hickory, NC (US);
`ene
`:
`(US):ChristopherPauickory,NC
`
`Hudson, NC (US); Thomas
`Theuerkorn, Hickory, NC (US)
`
`(73) Assignee: Corning Cable Systems LLC, Hickory,
`NC (US)
`
`(*) Notice:
`
`Subject to any disclaimer, the term ofthis
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 0 days.
`
`(21) Appl. No.: 11/820,277
`
`(22)
`
`Filed:
`
`Jun. 18, 2007
`
`4/1993 Collinsetal. 385/87
`5,202,942 A *
`7/1998 Manning.......
`.... 385/86
`5,781,681 A *
`
`ve 385/87
`5,835,653 A * 11/1998 Barkus......
`
`looeey hens are oo tke
`een ‘
`,134,
`ilders et al.
`...
`wee
`1/2001 Weigel eves 385/139
`6,178,283 BL*
`
`(Continued)
`FOREIGN PATENT DOCUMENTS
`
`EP
`
`0375669
`
`6/1990
`
`(Continued)
`OTHER PUBLICATIONS
`
`Patent Cooperation Treaty, International Search Report for Interna-
`tional Application No. PCT/US2008/007343, May 12, 2009, 2 pages.
`Primary Examiner—Ryan Lepisto
`
`(57)
`
`ABSTRACT
`
`Prior Publication Data
`US 2008/0310798 Al
`Dec. 18. 2008
`—
`
`(65)
`
`(51)
`
`A fiber optic plug assembly ofa fiber optic connector assem-
`bly is provided and generally includes a fiber optic plug
`mounted upon an end ofa fiber optic cable; a pre-molded boot
`placed overthe fiber optic plug andthe fiber optic cable; and
`Int. CL.
`a crimp band mated over the pre-molded boot to secure the
`(2006.01)
`GO2B 6/38
`boot to the fiber optic cable; wherein the fiber optic plug
`(2006.01)
`GO2B 6/36
`assembly is operable to mate to a fiber optic receptacle. The
`385/69: 385/55: 385/56:
`(52) U.S. Cl
`plug assembly eliminates the need for an overmolded boot.
`nn385/76:385/77: 385/78: 385/86: 385/87
`Further, the present invention eliminates the need to perform
`(58) Field of Classifi
`ch
`;
`"385/69
`tic
`S
`
`
`cen ONABSSTTCATIOT, SCABCIN woeseesseeseeee385/86 87 aheat shrink betweenthe buffer tube and crimp body through
`
`
`See applicationfile for complete search histo
`,
`the internal O-ring. The plug assembly meets the standards of
`PP
`P
`ry:
`GR-3120-COREwhile at the same time providing a simpler
`References Cited
`hardware package that can be assembled with ordinary con-
`nectorizationtools.
`U.S. PATENT DOCUMENTS
`
`(56)
`
`4,047,797 A
`
`9/1977 Amoldetal.
`
`.........0.. 350/96 C
`
`12 Claims, 7 Drawing Sheets
`
`10
`
`30
`
`Senko EX1025
`PGR2024-00037
`U.S. Patent No. 7,628,545
`
`Senko EX1025
`PGR2024-00037
`U.S. Patent No. 7,628,545
`
`

`

`US 7,628,545 B2
`
`Page 2
`
`U.S. PATENT DOCUMENTS
`
`6,601,997 B2*
`8/2003 Ngo os srereeerereceecreees 385/86
`6,674,951 Bl
`1/2004 _Erwimetal. wo... 385/134
`6,796,721 B2*
`.. 385/86
`9/2004 Matsumotoet al.
`
`6,817,780 B2* 11/2004 Ngo vccccccssssseseeeseeees 385/86
`6,932,515 B2
`8/2005 Ngo svvvessseeeeeesseseeeeen 385/86
`7,018,108 B2*
`3/2006 Makhlin etal. 0.0.0.0... 385/78
`7,150,567 B1* 12/2006 Lutheretal.
`......0.0000.. 385/78
`
`2002/0150352 AL* 10/2002 Ngo oo... eeeeeeeereeceeeee 385/86
`.. 385/86
`2003/0095754 Al*
`5/2003 Matsumotoetal.
`
`6/2004 Banasetal. oo... 385/86
`2004/0120656 Al*
`
`EP
`IP
`
`FOREIGN PATENT DOCUMENTS
`1431786
`6/2004
`3004-28729
`10/2004
`
`* cited by examiner
`
`

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`US 7,628,545 B2
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`eSSASSANS
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`Sheet 7 of 7
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`US 7,628,545 B2
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`US 7,628,545 B2
`
`1
`FIBER OPTIC PLUG ASSEMBLY WITH BOOT
`AND CRIMP BAND
`
`CROSS-REFERENCE TO RELATED
`
`APPLICATION(S)
`
`This Application incorporates by reference in its entirety
`for all purposes commonly assigned U:S. patent application
`Ser. No. 10/924,525 filed Aug. 24, 2004, andentitled “FIBER
`OPTIC RECEPTACLE AND PLUG ASSEMBLIES.” Fur-
`
`thermore, this Application incorporates by reference in its
`entirety for all purposes commonly assigned U.S. patent
`application Ser. No. 11/076,684 filed Mar. 10, 2005, and
`entitled “MULTI-FIBER FIBER OPTIC RECEPTACLE
`AND PLUG ASSEMBLY-”
`
`BACKGROUND OF THE INVENTION
`
`1. Field of the Invention
`
`The present invention relates generally to fiber optic con-
`nector assemblies, and more specifically, to fiber optic con-
`nector assemblies with a field-installable crimp-on boot and
`an O-ring on a plug assembly for interconnecting optical
`fibers within a fiber optic communications network.
`2. Technical Background of the Invention
`Optical fiber is increasingly being used for a variety of
`broadbandapplications including voice, video and data trans-
`missions. Asa result of the desire to expand telecommunica-
`tions networks, larger networks require a greater number of
`distribution cables, drop cables, assemblies and connecting
`hardware. One example of connecting hardware includes
`plug assemblies, also referred to herein as “connector assem-
`blies”, which are used to connectoptical fibers through recep-
`tacles, optical devices, hardware or other plugs. Plug assem-
`blies typically comprise the hardware mounted upon the end
`of a fiber optic drop cable and typically include at least one
`ferrule mounted upon the ends of one or more optical fibers
`for presenting the one or morefibers for optical connection
`with other opticalfibers.
`In addition to the foregoing, certain requirements have
`been established for connector assemblies andthe like. Spe-
`cifically, GR-3120-CORE, Issue 1, March 2005, Generic
`Requirements for Hardened Fiber Optic Connectors
`(HFOCs), issued by Telcordia Technologies, Inc. of Piscat-
`away, N.J., contains requirements for connectors that are
`field-mateable and hardened (also knownas ruggerdized) for
`use in the outside plant. These requirements are needed to
`support FTTx deploymentandservice offerings. GR-3120-
`COREincludes generic requirements for HFOCsfor passive
`telecommunications components used in an Outside Plant
`(OSP) environment. HFOCsprovide drop connectionsto cus-
`tomers from fiber distribution networks, such as FTTx, and
`maybe provided in pedestal closures, aerial and buried clo-
`sures, or equipmentlocated at a customer premises, such as a
`Fiber Distribution Hub (FDH)or optical network termination
`unit. Through the GR-3120-COREspecifications, HFOCs
`are specified to withstand climatic conditions including ambi-
`ent temperatures ranging from -40° C. (-40° F.) to +70° C.
`(158° F.).
`To meet the demanding GR-3120-COREspecifications,
`smaller conventional connector assembly packages are
`needed by network providers. These connector assembly
`packages typically include an overmolded boot, glue body
`based solution or a heat shrink seal. The heat shrink seal has
`increased cost and is not as robust as an overmolded boot.
`Overmolded boots are knownin theart for sealing the rear end
`of the plug housing and for providing strain relief. For
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
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`60
`
`65
`
`2
`example, the plug assembly can include a high-pressure over-
`molded boot made ofa flexible(e.g., silicone-typeor the like)
`material secured overa rear portion of the plug assembly and
`a portion ofthe drop cable in order to seal the exposed portion
`of the drop cable while generally inhibiting kinking and pro-
`viding bendingstrain relief to the drop cable near the plug. A
`glue body material is injected between a buffer tube and a
`crimp body, but leakage occurs due to shrinkage of the mate-
`rial. Additionally, the overmolded boot materialis very stiffto
`meet the GR-3120-COREside load requirement, thus the
`overmolded boot material melt temperatures are high, result-
`ing in damageto the buffer tube further complicating sealing
`whenthe overmolded boot, crimp body, and buffer tube are
`heated to form a seal.
`
`The overmolded boot, crimp body, and the like provide a
`robust mechanical andseal integrity performancefor the con-
`nector assembly to meet the GR-3120-COREspecifications
`inasmaller connector assembly. These solutions are provided
`in factory assembly. However, these solutions are not simple
`to execute in a typical cable assembly houseorin the field.
`Whatis needed, therefore, is a simpler hardware packagethat
`can be assembled with ordinary connectorization tools. It
`would also be desirable to provide a simpler hardware pack-
`age fora fiber optic connector and plug assembly which meets
`the demanding GR-3120-COREspecification. Such fiber
`optic connector and plug assemblies would desirably be pro-
`vided with a crimp on pre-moldedboot and O-ring between a
`buffer tube on a drop cable and a crimp body in the plug
`assembly.
`
`BRIEF SUMMARY OF THE INVENTION
`
`To achieve the forgoing and other objects, and in accor-
`dance with the purposes ofthe present invention as embodied
`and broadly described herein, the present invention provides
`various embodimentsofa fiber optic plug assembly and plug
`assembly components including a crimp-on pre-molded boot
`and O-ring between a buffer tube on a drop cable and a crimp
`body in the plug assembly. Advantageously,
`the present
`invention eliminates an overmolded boot, providing a more
`readily installed plug assembly. Further, the present invention
`eliminates the need to perform a heat shrink between the
`buffer tube and crimp body by using an internal O-ring. The
`present invention does not require significant investments in
`molds andpressesto install the connector assembly. The plug
`assemblyof the present invention meets the demandingstan-
`dards specified in GR-3120-CORE while at the same time
`providing a more simple hardware package that can be
`assembled with ordinary tools.
`In one exemplary embodiment, the present invention pro-
`vides a hardenedfiber optic plug assembly including: a fiber
`optic plug mounted upon an end of a fiber optic cable, a
`pre-molded bootplaced overthefiber optic plug andthe fiber
`optic cable, and a crimp band mated overthe pre-molded boot
`to secure the bootto the fiber optic cable, wherein the fiber
`optic plug assembly is operable to mateto a fiber optic recep-
`tacle, fiber optic plug or other hardware or device. The hard-
`ened fiber optic plug assembly further includes a buffer tube
`at the end ofthe fiber optic cable, an O-ring located on the
`buffer tube, and an O-ring pusher tube located on the buffer
`tube behind the O-ring relative to the end ofthe fiber optic
`cable, wherein the pushertube is operable to seat the O-ring
`betweenthe buffer tube anda crimp bodycreated by the crimp
`bandand pre-molded boot. The O-ring is operable to seal the
`plug assembly, and wherein the O-ring pusher tube provides
`protection for the buffer tube. The plug assembly substan-
`tially meets GR-3120-COREspecifications. Optionally, the
`
`

`

`US 7,628,545 B2
`
`3
`pre-molded bootincludes rubber or other elastomeric mate-
`rial, and the crimp bandincludes brass or other deformable
`material. The boot and crimp bandtogether provide sealing
`and strain relief such that the plug assembly substantially
`meets GR-3120-COREspecifications. The hardened fiber
`optic plug assembly further includes a stamped metallic
`strength element engaged between the crimp band and the
`pre-molded boot. Optionally, the stamped metallic strength
`element is madeto the pre-molded boot.
`In another exemplary embodiment, the present invention
`provides a hardened fiber optic plug assembly including: a
`buffer tube upon an endofa fiber optic cable, a plug sub-
`assembly mounted uponthe end ofthe fiber optic cable over
`the buffer tube, an O-ring located on the buffer tube, and an
`O-ring pusher tube located on the buffer tube behind the
`O-ring relative to the end of the fiber optic cable, wherein the
`pushertube is operable to seat the O-ring betweenthe buffer
`tube and the plug sub-assembly. Optionally, the hardened
`fiber optic plug assembly further includes a pre-molded boot
`placed overthe fiber optic plug andthefiber optic cable, and
`a crimp band mated over the pre-molded boot to secure the
`bootto the fiber optic cable. Alternatively, the hardenedfiber
`optic plug assembly further includes a high-pressure over-
`molded boot secured overa rear portion of the plug assembly
`and an endof a fiber optic cable, and a glue body material
`injected between the buffer tube and a crimp body. The plug
`assembly substantially meets GR-3120-CORE specifica-
`tions.
`
`In yet another exemplary embodiment, the present inven-
`tion provides a fiber optic plug assembly including: a plug
`sub-assembly matedto a plurality of optical fibers in a fiber
`optic cable, a plug outer housing located substantially over
`the plug sub-assembly, a pre-molded boot located substan-
`tially over the plug sub-assembly andthe fiber optic cable,
`and a crimp band mated over the pre-molded boot to secure
`the bootto the fiber optic cable and to seal the fiber optic plug.
`The plug assembly substantially meets GR-3120-CORE
`specifications. The fiber optic plug assembly further includes
`a coupling nut located over the plug outer house and operable
`to mate with a fiber optic receptacle. The outer housing
`includes a key slot for aligning the plug with the receptacle.
`Optionally, the fiber optic plug assembly further includes a
`buffer tube at the end of the fiber optic cable, an O-ring
`located on the buffer tube, an O-ring pusher tube located on
`the buffer tube behind the O-ring relative to the end of the
`fiber optic cable, wherein the pushertube is operable to seat
`the O-ring between the buffer tube and a crimp body created
`by the crimp band and pre-moldedboot. The O-ring is oper-
`able to seal the plug assembly, and wherein the O-ring pusher
`tube provides protection for the buffer tube. Optionally, the
`boot is provided with a port for introducing adhesive. Option-
`ally, splines are added to the large inner diameter of the
`slide-up boot to prevent adhesive from flowing during its
`liquid stage.
`Additional features and advantagesofthe invention will be
`set forth in the detailed description which follows, 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 detailed description which
`follows, the claims, as well as the appended drawings.
`It is to be understood that both the foregoing general
`description and the following detailed description present
`exemplary embodimentsofthe 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
`
`4
`constitute a part of this specification. The drawingsillustrate
`various embodiments of the invention, and together with the
`detailed description, serve to explain the principles and
`operations thereof.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The present invention is illustrated and described herein
`with reference to the various drawings, in which like refer-
`ence numbers denote like components, and in which:
`FIG. 1 is a perspective view of one embodimentof a plug
`assembly including a pre-molded boot and crimp band.
`FIG.2 is a perspective view of the plug assembly in FIG. 1
`shown with the crimp band disengaged from the pre-molded
`boot.
`FIG.3 is a perspective view of the crimp bandin FIG.1.
`FIG.4 is a cross-sectional view of the pre-molded boot in
`FIG.1.
`
`20
`
`FIG. 5 is a cross-sectional view of the plug assembly in
`FIG.1 including an internal O-ring between the crimp body
`and a buffer tube.
`
`25
`
`30
`
`35
`
`FIG.6 is a cut-away perspective view of a plug assembly
`including a stamped metallic strength element engaged
`between the crimp band andthe pre-molded boot.
`FIG.7 is a cross-sectional view of another embodiment of
`
`a plug assembly
`FIG.8 is a cut-away perspective view ofthe plug assembly
`in FIG.7.
`
`FIG. 9 is another embodimentof a plug assembly including
`a sheath retention feature clamped about the drop cable.
`FIG.10 is a cut-away perspective view of a plug assembly
`including a splined boot defining an adhesive port.
`FIG. 11 is a perspective view ofthe splined boot of FIG. 10.
`FIG.12is a perspective view of a plug assembly including
`scallops removed from the jacket to aid in drop cable reten-
`tion to heat shrink.
`
`FIG.13 is a perspective view of the plug assembly of FIG.
`12 including heat shrink.
`
`40
`
`DETAILED DESCRIPTION OF THE INVENTION
`
`45
`
`50
`
`55
`
`60
`
`65
`
`The present invention will now be described more fully
`hereinafter with reference to the accompanying drawings in
`which exemplary embodiments of the invention are shown.
`However, this invention may be embodied in manydifferent
`forms and should not be construed as limited to the embodi-
`ments set forth herein. These exemplary embodiments are
`provided so that this disclosure will be both thorough and
`complete, and will fully convey the scope of the invention to
`those skilled in the art.
`
`In the various embodiments described below, the present
`invention provides a crimp-on pre-molded boot and O-ring
`between a buffer tube on a drop cable and a crimp body in the
`plug assembly ofa fiber optic connector assembly. Advanta-
`geously and in various exemplary embodiments described
`herein, the present invention eliminates an overmolded boot,
`providing a simplerto install connector assembly. Further, the
`present invention eliminates the need to perform a heat shrink
`between the buffer tube and crimp bodyby using an internal
`O-ring. The present invention does not require significant
`investments in molds and presses to install the connector
`assembly. The plug assembly of the present invention meets
`the demanding standards specified in GR-3120-COREwhile
`at the same time providing a simpler hardware package that
`can be assembled with ordinary connectorization tools. Other
`improvements as a result of the structural changes include
`improvements with respect to optical fiber alignment and
`
`

`

`US 7,628,545 B2
`
`5
`connectivity within and between drop cables and a subscrib-
`er’s premises. Thus, the present invention provides a plug
`assembly designed to readily interconnect and align optical
`fibers while providing relief against mechanical forces.
`The present invention also provides improvementsin seal-
`ing. The mostdifficult seal to achieve is between the buffer
`tube and crimpbody. This can be sealed through a heatshrink,
`but this is difficult and requires a flash test to verify. The
`present invention provides an O-ring between the buffer tube
`and the crimp body. This O-ring is most advantageously
`positioned throughthe use of a short section oftubing behind
`the O-ring. This provides accurate control over sealing and
`provides additional protection for the buffer tube at the tran-
`sition point to the connector body.
`Referring now to FIGS. 1-8, a fiber optic plug 10 assembly
`operable for use with a fiber optic connector assembly is
`illustrated in accordance with in exemplary embodiment of
`the present invention. As shown, the fiber optic plug 10
`includes components such as an outer housing 12, an align-
`ment sleeve 14, a plug sub-assembly 16 for maintaining a
`plug ferrule (not shown), a lengthwise passage 18, a crimp
`band 20, a pre-molded boot 30, and a coupling nut 28. The
`plug is mounted uponthe end of a fiber optic cable, such as a
`drop cable 50. Although not shown,the plug 10 may be mated
`to a fiber optic receptacle. The plug 10 andthe receptacle are
`operable for aligning and maintaining the optical fiber in
`opposingrelation for transmitting an optical signal.
`To secure the plug 10 to a receptacle, a threaded coupling
`nut engages a threaded end of the receptacle or vice-versa.
`The plug 10 includes the pre-molded boot 30 and crimp band
`20. To eliminate the overmolded boot in conventional plugs,
`a simple slide-on bootis not possible dueto the 10-15 Ibs. side
`load requirement in GR-3120-CORE,and the tendency of
`slip-on boots to bell mouth and provide reduced support for
`the drop cable assembly. The pre-molded boot 30 is placed
`upon the end of the drop cable 50. The pre-molded boot 30
`can be madeofa flexible (silicone-type or the like) material
`and is provided for sealing the exposed portion of the drop
`cable while generally inhibiting kinking and providing bend-
`ing strain relief to the cable. Although not shown, the end of
`the drop cable 50 includes a stripped back cable jacket,
`strength components, and one or morefibers such as an opti-
`cal ribbon comprising a plurality of optical fibers 54. The
`crimp band20 is placed over the pre-molded boot 30 and the
`drop cable 50, and crimped using ordinary tools to secure the
`boot 30 to the drop cable 50. Accordingly, the crimp band 20
`secures the pre-molded boot 30 in place over the drop cable
`50. The crimp band 20 can be made of brass or another
`suitable deformable material. In addition to sealing and secur-
`ing the pre-molded boot 30, the crimp band 20 also provides
`strain relief for the drop cable 50. Also, the end of the outer
`housing 12 includes a key slot 22 for aligning the plug 10 with
`the receptacle, and consequently, the plug sub-assembly 16
`relative to the receptacle, and also providing selective mating.
`Thus, the plug 10 and corresponding receptacle are config-
`ured to permit mating in only oneorientation.
`Referring to FIG.2, the fiber optic plug 10 is shown with
`the pre-molded boot 30, crimp band 20, outer housing 12, and
`plug sub-assembly 16 disengaged. The pre-molded boot 30 is
`placed over the drop cable 50. The plug sub-assembly 16 is
`assembled by crimping the crimp band 20 around a rear
`knurled portion. As is well understood by those of ordinary
`skill in the art, the outer housing 12 and a coupling nut 28
`(depicted in FIGS. 7-8) are threaded onto the drop cable 50
`before the sub-assembly 16. The outer housing 12 is then slid
`over the sub-assembly 16. In one embodiment,
`the pre-
`molded boot 30 and the crimp band 20 are separate compo-
`
`20
`
`25
`
`30
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`35
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`40
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`45
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`50
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`6
`nents. In another embodiment, the pre-molded boot 30 and
`the crimp band 20 could be a boot insert molded onto a
`mandrel. The mandrel would in turn be crimpedto the back of
`the connector to provide adequate boot retention andresis-
`tance to bell mouthing. The pre-molded boot 30 defines a
`forward end 32 positioned about a buffer tube 52.
`Referring to FIG. 3, in an exemplary embodiment, the
`crimp band 20 includes a forward end 24 and a rearward end
`26. The forward end 24 includes a passagewaysizedto fit over
`the plug sub-assembly 16 andthe endof the drop cable 50.
`The rearward end 26 includes a passagewaysizedto fit over a
`forward end 32 of the pre-molded boot 30.
`Referring to FIG. 4, in an exemplary embodiment, the
`pre-molded boot 30 includes the forward end 32 anda rear-
`ward end 34. The forward end 32 includes a passageway sized
`to fit over the plug sub-assembly 16 and the end of the drop
`cable 50. The rearward end 34 includes a passagewaysized to
`fit over the drop cable 50.
`Referring to FIG. 5, a cut-away of the plug 10 assembly is
`shownwith an internal O-ring 40. For environmentalreasons,
`the plug 10 mustbe sealed between a buffer tube 52 at the end
`of the drop cable 50 and a crimp body portion of the pre-
`molded boot 30. The crimp body portion is where the crimp
`band 20 secures the pre-molded boot 30. The buffer tube 52
`includes an opening with a plurality ofoptical fibers 54 which
`are matedto the plug sub-assembly 16. As described herein,
`conventionally this seal is done witha heat shrink followed by
`a flash test to verify the seal. The present invention provides
`an internal O-ring 40 and an O-ring pusher 42 between the
`buffer tube 52 and the crimp body. The O-ring 40is positioned
`by the O-ring pusher 42 which is a short section of tubing
`located behindthe O-ring 40 on the buffer tube 52. The O-ring
`pusher 42 provides accurate control over seating ofthe O-ring
`40, and additional protection for the buffer tube 52 at the end
`point ofthe drop cable 50 wherethe plug 10 attaches. Advan-
`tageously, the use ofthe O-ring 40 to seal the buffer tube 52 is
`better than the straight injection molding approach. Com-
`pared to the use of heat shrink in the plug assembly 10, the
`O-ring 40 eliminates an expensive operation and complex
`operation. This can eliminate the needto test for leaks in the
`plug assembly 10.
`To further protect the buffer from damage, a strength com-
`ponent 56, such as glass-reinforced plastic (GRP)or the like,
`is included between the plug sub-assembly 16 and the crimp
`body. The O-ring 40 of the present invention can also be
`utilized in an overmolded boot connector assembly. The
`O-ring 40 could be combined with an overmolded boot to
`provide additional robustness. This can eliminate the flash
`test, but would still require the use of a conventional glue
`body. Specifically, the O-ring pusher 42 provides not only a
`placementtool, but a thermal barrier as well. The pusher 42
`allows the use of a high melt temperature. Additionally, to
`solve the buffer tube 52 damage dueto the heat and pressure
`of the injection molding process, the tubing was changed to
`Teflon orthe like based product with a high melt temperature.
`This O-ring 40 and O-ring pusher 42 solution can be utilized
`in any hardened connector.
`The outer housing 12 of the plug 10 may further define a
`shoulder that servers as a mechanical stop for a conventional
`elastrometric O-Ring 44 against a forward radial surface
`thereof and for the coupling nut 28 against a rearwardradial
`surface thereof. This O-Ring 44 provides another environ-
`mental seal when the coupling nut 28 engages a threaded
`portion of the receptacle.
`Referring to FIG. 6, in another exemplary embodiment, a
`cut-away perspective view of the plug assembly 10 including
`a stamped metallic strength element 60 engaged between a
`
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`

`US 7,628,545 B2
`
`7
`crimp band 80 and a molded rubber boot 70 is shown. The
`strength element 60 includes a rolled edge to prevent the
`molded rubber boot 70 from pulling off. The molded rubber
`boot 70 is made to the metallic strength element 60 and placed
`onto the plug 10 and drop cable 50 as a single assembly. The
`crimp band 80 is placed over a frontward portion of the
`metallic strength element 60 and the outer housing 12, and
`crimped using ordinary connectorization tools. Additionally,
`the coupling nut 28 is shown over the outer housing 12. As
`described herein, the coupling nut 28 secures the plug 10 to
`the receptacle.
`Referring to FIGS. 7-8, a cross-sectional and cut-away
`perspective view are shown of another exemplary embodi-
`mentofthe plug assembly 10. As in FIG.6, the molded rubber
`boot 70 is madeto the strength element 60 and placed at the
`end ofthe drop cable 50. The crimp band (not shown in FIGS.
`7-8) is operable to secure the molded rubber boot 70 and the
`strength element 60 to the drop cable 50 thereby forming a
`seal andstrain reliefto secure the plug assembly 10. The plug
`sub-assembly 16 mates with the end of the drop cable 50 as
`described herein. The plug assembly 10 mayalso include the
`alignment sleeve 14 operable to align the optical fibers
`between the plug 10 andthe receptacle, as well as a length-
`wise passage 18 operable to receive a plug ferrule and a
`receptacle ferrule.
`Referring to FIG.9, a cut-away perspective view ofanother
`plug assembly is shown. The plug assembly 90 includes a
`preformed boot30 defining a surface 92 for receiving a crimp
`band 94. The assembly further includes a sheath retention
`band 96 disposed about a portion of the drop cable 50 for
`further holding the boot 30 in position. Optionally, the reten-
`tion band 96 maybe notchedordefine grabbing portions 98 to
`further hold the boot 30 in position. In an alternative embodi-
`ment, the preformed boot 30 may be substituted for a heat
`shrink.
`
`Referring to FIGS. 10 and 11, a cut-away perspective view
`of another embodimentof a plug assembly 100, and an iso-
`lated view of a boot 102 are shown. The assembly 100
`includes, among other components, a preformed boot 102
`defining a first end 104 positioned over outer housing 12 and
`a second end 106 positioned overa portion of the drop cable
`50. As in the previous embodiments, the second end 106 of
`the boot 102 may define an opening that corresponds in shape
`to the drop cable upon which it is mounted. In the embodi-
`ment shown,the drop cable 50 is a ribbon-type cable andis
`non-round. The boot 102 further defines an opening 108
`therethroughfor introducing an epoxy, adhesiveor like mate-
`rial for sealing. Referring specifically to FIG. 11, splines 110
`mayoptionally be addedthe large inner diameteroftheslide-
`up boot 102 to prevent adhesive from flowing during liquid
`stage of the adhesive.
`Referring to FIGS. 12 and 13, an alternative embodiment
`of a plug assembly 120 is shown that includes, among other
`components, cuts 122 or scalloping madein a portion of the
`cable jacket 124to aid in drop cable retention to heat shrink
`126. The heat shrink 126, when shrunk, follows the contour of
`the scalloped cable sheath,
`thereby improving retention
`between the two components.
`As will be understood by those skilled in the art, the plug
`assembly may include and be changed in shape to accommo-
`date any type offiber optic connector or cable type such as,
`but not limited to, SC, LC, FC, MTRJ, MTP andother con-
`nectors. Although the present invention has been illustrated
`and described herein with reference to preferred embodi-
`ments and specific examples thereof, it will be readily appar-
`ent to those of ordinary skill in the art that other embodiments
`and examples may perform similar functions and/or achieve
`
`20
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`25
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`30
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`like results. All such equivalent embodiments and examples
`are within the spirit and scopeofthe present invention and are
`intended to be covered by the following claims.
`Whatis claimedis:
`1.A fiber optic assembly, comprising:
`a fiber optic plug mounted upon an end ofa fiber optic
`cable;
`a pre-molded boot placed overthe fiber optic plug and the
`fiber optic cable;
`a crimp band mated over the pre-molded boot to secure the
`boot to the fiber optic cable;
`a buffer tube at the endof the fiber optic cable;
`an O-ring located on the buffer tube; and
`an O-ring pusher tube located on the buffer tube behind the
`O-ring relative to the end of thefiber optic cable, wherein the
`pushertube is operable to seat the O-ring between the buffer
`tube and a crimp body created by the crimp band andpre-
`molded boot.
`2. The fiber optic assembly of claim 1, wherein the pre-
`moldedbootdefines an opening therethrough for introducing
`adhesive.
`
`3. The fiber optic assembly of claim 1, wherein the assem-
`bly meets GR-3120-COREspecifications.
`4. The fiber optic assembly ofclaim 1, wherein the boot and
`crimp bandprovide sealing andstrain relief such that the plug
`assembly meets GR-3120-COREspecifications.
`5. The fiber optic assembly of claim 1, further comprising
`a strength element engaged between the crimp band and the
`pre-molded boot.
`6. A fiber optic plug assembly, comprising:
`a buffer tube upon an endofa fiber optic cable;
`a plug sub-assembly mounted upon the end ofthe fiber
`optic cable over the buffer tube;
`an O-ring located on the buffer tube;
`an O-ring pushertube located on the buffer tube behind the
`O-ring relative to the end of the fiber optic cable,
`wherein the pusher tube is operable to seat the O-ring
`between the buffer tube and the plug sub-assembly;
`a pre-molded bootplaced over the plug sub-assembly and
`the fiber optic cable; and
`acrimp band mated overthe pre-molded bootto secure the
`boot to the fiber optic cable.
`7. The fiber optic plug assembly of claim 6, further com-
`prising:
`the pre-molded boot secured overa rear portion of the plug
`sub-assembly and an endofthe fiber optic cable; and
`a glue body material injected between the buffer tube anda
`crimp body.
`8. The fiber optic plug assembly of claim 6, wherein the
`fiber optic plug assembly meets GR-3120-COREspecifica-
`tions.
`9. A fiber optic plug assembly, comprising;
`a plug sub-assembly mounted upona fiber optic cable;
`a plug outer housing located substantially over the plug
`sub-assembly;
`a pre-molded boot located substantially over the plug sub-
`assembly andthefiber optic cable;
`acrimp band mated overthe pre-molded bootto secure the
`boot to the fiber optic cable and to seal the fiber optic
`plug;
`a buffer tube at the endofthe fiber optic cable;
`an O-ring located on the buffer tube; and
`an O-ring pushertube located on the buffer tube behind the
`O-ring relative to the end of the fiber optic cable,
`wherein the pusher tube is operable to seat the O-ring
`between the buffer tube and a crimp bodycreated by the
`crimp band and pre-molded boot.
`
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`

`US 7,628,545 B2
`
`9
`10. The fiber optic plug assembly of claim 9, wherein the
`plug assembly meets GR-3120-COREspecifications.
`11. Thefiber optic plug assembly of claim 9, further com-
`prising a coupling nut located ove