Patent Publication Number: US-2023152530-A1

Title: Ruggedized push-pull fiber optic connection systems

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is being filed on Apr. 2, 2021 as a PCT International Patent Application and claims the benefit of U.S. Patent Application Ser. No. 63/004,400, filed on Apr. 2, 2020, and claims the benefit of U.S. Patent Application Ser. No. 63/089,678, filed on Oct. 9, 2020, the disclosures of which are incorporated herein by reference in their entireties. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates generally to fiber optic connectors. More particularly, the present disclosure relates to fiber optic connectors suitable for outside environmental use. 
     BACKGROUND 
     Fiber optic communication systems are becoming prevalent in part because service providers want to deliver high bandwidth communication capabilities (e.g., data and voice) to customers. Fiber optic communication systems employ a network of fiber optic cables to transmit large volumes of data and voice signals over relatively long distances. Optical fiber connectors are an important part of most fiber optic communication systems. Fiber optic connectors allow two optical fibers to be quickly optically connected without requiring a splice. Fiber optic connectors can be used to optically interconnect two lengths of optical fiber. Fiber optic connectors can also be used to interconnect lengths of optical fiber to passive and active equipment. 
     A typical fiber optic connector includes a ferrule assembly supported at a distal end of a connector housing. A spring is used to bias the ferrule assembly in a distal direction relative to the connector housing. The ferrule functions to support an end portion of at least one optical fiber (in the case of a multi-fiber ferrule, the ends of multiple fibers are supported). The ferrule has a distal end face at which a polished end of the optical fiber is located. When two fiber optic connectors are interconnected, the distal end faces of the ferrules abut one another and the ferrules are forced proximally relative to their respective connector housings against the bias of their respective springs. With the fiber optic connectors connected, their respective optical fibers are coaxially aligned such that the end faces of the optical fibers directly oppose one another. In this way, an optical signal can be transmitted from optical fiber to optical fiber through the aligned end faces of the optical fibers. For many fiber optic connector styles, alignment between two fiber optic connectors is provided through the use of an intermediate fiber optic adapter. 
     Ruggedized (i.e., hardened) fiber optic connection systems include fiber optic connectors and fiber optic adapters suitable for outside environmental use. These types of systems are typically environmentally sealed and include robust fastening arrangements suitable for withstanding relatively large pull loading and side loading. Example ruggedized fiber optic connection systems are disclosed by U.S. Pat. Nos. 7,467,896; 7,744,288 and 8,556,520. 
     SUMMARY 
     Certain aspects of the present disclosure relate to ruggedized push-pull connection systems. One example push-pull connection system includes connector sealing at a location inwardly positioned within a connector port with respect to a push-pull latching arrangement for latching a fiber optic connector in the connector port. Another example push-pull connection system includes a fiber optic connector with an integral latch for latching the connector within a connector port, and also includes sealing on the inside and the outside of a release sleeve of the fiber optic connector. 
     A variety of additional inventive aspects will be set forth in the description that follows. The inventive aspects can relate to individual features and to combinations of features. It is to be understood that both the forgoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the broad inventive concepts upon which the embodiments disclosed herein are based. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    depicts an example push-pull fiber optic connection system in accordance with the principles of the present disclosure; 
         FIG.  2    depicts an example push-pull fiber optic connector of the push-pull fiber optic connection system of  FIG.  1   ; 
         FIG.  3    depicts an example fiber optic adapter of the push-pull fiber optic connection system of  FIG.  1   ; 
         FIG.  4    depicts an example push-pull latching arrangement of the push-pull fiber optic connection system of  FIG.  1   , the latching arrangement being depicted in a latched state; 
         FIG.  5    depicts the push-pull latching arrangement of  FIG.  4    in an unlatched state; 
         FIG.  6    depicts another example push-pull fiber optic connection system in accordance with the principles of the present disclosure; 
         FIG.  7    depicts an example fiber optic adapter of the push-pull fiber optic connection system of  FIG.  6   ; 
         FIG.  8    depicts an example push-pull fiber optic connector of the push-pull fiber optic connection system of  FIG.  6   ; 
         FIG.  9    depicts the push-pull fiber optic connector of  FIG.  8    with a dust cap installed over a plug end of the fiber optic connector; 
         FIG.  10    depicts an example push-pull latching arrangement of the push-pull fiber optic connection system of  FIG.  6   , the latching arrangement being depicted in a latched state; 
         FIG.  11    depicts the push-pull latching arrangement of  FIG.  10    in an unlatched state; 
         FIG.  12    depicts a first type of shroud being mounted over the push-pull connector of  FIGS.  6 - 11   ; 
         FIG.  13    depicts the first type of shroud assembled on the connector of  FIGS.  6 - 11    to form a first type of ruggedized connector; 
         FIG.  14    is an axial cross-section of the first type of ruggedized connector of  FIG.  13   ; 
         FIG.  15    depicts a second type of shroud being mounted over the push-pull connector of  FIGS.  6 - 11   ; 
         FIG.  16    depicts the second type of shroud assembled on the connector of  FIGS.  6 - 11    to form a second type of ruggedized connector; 
         FIG.  17    is an axial cross-section of the second type of ruggedized connector of  FIG.  16   . 
     
    
    
     DETAILED DESCRIPTION 
     The expansion of fiber optic networks toward the premises has driven the demand for enhanced fiber optic connectors suitable for outside environmental uses. For example, in a given fiber optic network, outside fiber optic connectors are used to connect fiber optic cables to structures such as drop terminals (i.e., multi-service terminals), optical network terminals (ONTs), breakout locations on fiber optic cables, fiber distribution hubs, splice closures, pedestals, or other structures. Effective use of fiber optic connectors in outside environments requires the fiber optic connectors to be sealed against the environment and to have robust designs that can withstand relatively large temperature variations, large pulling loads, and significant side loading. It is also desirable for such connectors to be relatively easy to insert and remove from a port in a structure of the type described above. The present disclosure describes various connectors having rugged, robust designs that are environmentally sealed and that are relatively easy to install and uninstall in the field. 
       FIG.  1    depicts an example push-pull fiber optic connection system  20  in accordance with the principles of the present disclosure. The push-pull fiber optic connection system  20  includes a structure  22  defining a connector port  24 . The push-pull fiber optic connection system  20  also includes a push-pull fiber optic connector  26  adapted to be latched and sealed within the connector port  24  via a push-pull latching arrangement. The latching arrangement is configured to latch the push-pull fiber optic connector  26  within the connector port  24  when the connector  26  is pushed into the connector port  24  and to unlatch the connector  26  with respect to the connector port  24  when the connector  26  is pulled from the connector port  24  (e.g., by grasping and pulling on a release sleeve  50  of the connector  26 ). In one example, the push-pull latching arrangement allows for single-handed installation of the connector  26  in the connector port  24  and single-handed disengagement of the connector  26  from the connector port  24 . 
     Referring to  FIGS.  1  and  3   , the structure  22  defining the connector port  24  is depicted as a fiber optic adapter  28 . A fiber optic adapter is a structure for mechanically and optically coupling two fiber optic connectors together. A fiber optic adapter often includes a ferrule alignment sleeve (e.g., see sleeve  30 ) for co-axially aligning the ferrules of two fiber optic connectors inserted within opposite ports of the fiber optic adapter. A fiber optic adapter can include an adapter housing that defines the connector ports. The adapter housing can include one or more parts. 
     In other examples, one or more connector ports of a fiber optic adapter can be defined by structures other than adapter housings. For example, one or both of the connector ports of a fiber optic adapter can be defined directly in the wall of an enclosure. Fiber optic connectors received in fiber optic adapters include single fiber connectors, multi-fiber connectors, ruggedized fiber optic connectors, non-ruggedized connectors (e.g., SC connectors, LC connectors, MPO connectors, etc.), and simplified fiber optic connectors which in certain cases may include only a ferrule. 
     Referring to  FIGS.  1  and  3   , the fiber optic adapter  28  includes an adapter housing  32  having the connector port  24  accessible at one end and another connector port  34  accessible at an opposite end. A ferrule alignment sleeve  30  can be mounted within the housing  32  in axial alignment with the connector ports  24 ,  34 . The adapter  28  can be mounted in a sealed manner within an opening  35  defined through a wall  36  of an enclosure  38 . For example, the structure  22  may include a flange to compress a seal (e.g., a radial seal) against an exterior of the wall  36 . A nut or other fastener may be mounted to the structure  22  at the opposite side of the wall  36 . In certain examples, the body of the structure may include a rounded portion defining threads over which the fastener may tighten. As so mounted, the connector port  24  is accessible from outside the enclosure  38  and the connector port  34  is located at an interior of the enclosure  38 . 
     As depicted at  FIG.  1   , a fiber optic connector  40  is secured within the connector port  34  and is positioned such that the fiber optic connector  26  optically couples with the connector  40  when the fiber optic connector  26  is latched within the connector port  24 . In one example, the connector  40  has a ferrule received in one end of the ferrule alignment sleeve  30  and the connector  26  includes a ferrule  42  that is received in an opposite end of the sleeve  30  when the connector  26  is latched in the connector port  24 . 
     Referring to  FIG.  2   , the fiber optic connector  26  includes a connector body  44  defining a plug portion  46  sized and shaped for insertion into the connector port  24 . The fiber optic connector  26  includes a port seal  48  on the connector body  44  for sealing within the connector port  24  (e.g., against a surface defining the connector port  24 ) when the fiber optic connector  26  is inserted in the connector port  24 . The fiber optic connector  26  also including a release sleeve  50  that is axially moveable relative to the connector body  44  along an axis  52  of the connector  26 . 
     The fiber optic connection system  20  includes a latching arrangement for securing the fiber optic connector  26  within the connector port  24 . The latching arrangement is configured to automatically latch the connector body  44  within the connector port  24  when the fiber optic connector  26  is pushed into the connector port  24  in an inward axial direction  54 . The latching arrangement also is configured to unlatch when the release sleeve  50  is pulled in an outward axial direction  56  while the connector body  44  is latched within the connector port  24  to allow the fiber optic connector  26  to be withdrawn in the outward axial direction  56  ( FIG.  5   ) from the connector port  24 . The port seal  48  is located inwardly within the connector port  24  with respect to the latching arrangement when the connector body  44  is latched within the connector port  24 . 
     The plug portion  46  of the connector body  44  includes a first region  60  defining a round transverse cross-sectional profile and a second region  62  defining a polygonal (e.g., depicted as square) transverse cross-sectional profile. The adapter  28  preferably includes an inner passage with a cross-sectional profile that complements the outer shape of the plug portion of the connector body  44 . The port seal  48  is depicted as a radial seal than mounts within a circumferential groove  64  defined at the first region  60  of the plug portion  46 . The latching arrangement includes latch catches  66  provided at sides of the polygonal transverse cross-section profile of the second region  62 . Preferably, at least 2, 3 or 4 latch catches are provided. Each latch catch  66  includes a retention surface  68  and a ramp surface  70 . The seal  48  is mounted axially between the second region  62  and a plug end  72  of the connector body  44 . The fiber optic connector  26  includes the ferrule  42  which is located at the plug end  72  and can be spring biased relative to the connector body  44  by a spring  74 . The ferrule  42  supports one or more optical fibers  76  corresponding to a fiber optic cable  78  anchored to a cable anchoring end of the connector body  44 . The connector body  44  can be formed by one or more connector body pieces. The cable  78  can be anchored to the connector body  44  by a crimp, adhesive or the like. As depicted, a shape memory sleeve  82  (e.g., a heat shrink sleeve) containing adhesive is used to secure the cable  78  to the connector body  44  and to provide a seal between the cable  78  and the cable anchoring end of the connector body  44 . 
     The latching arrangement also includes resilient latches  90  that are biased by their own inherent elasticity toward a latching position (see  FIG.  4   ). The latches are adapted to engage the retention surfaces  68  of the latch catches  66  to latch the connector  26  within the connector port  24  (see  FIG.  4   ). The latches  90  are provided at the connector port  24 . In one example, the latches  90  are integral with the adapter housing. Each of the latches includes a ramp surface  92  and a retention surface  94 . 
     The release sleeve  50  is axially moveable relative to the connector body  44 . A range of axial movement of the release sleeve  50  is limited by a stop arrangement including stops  96 ,  98  provided on the connector body  44  between which a stop  100  of the release sleeve  50  is captured. The sleeve  50  is axially moveable between an extended position (see  FIG.  4   ) and a retracted position (see  FIG.  5   ). The release sleeve  50  includes a ramp surface  102 . The latches  90  have projections  104  that fit in recesses  106  defined by the sleeve  50  when the latches are in the latching position and the release sleeve  50  is in the extend position. The projections  104  can retain the release sleeve  50  in the extended position when the connector  26  is latched within the connector port  24 . 
     When the connector  26  is pushed into the connector port  24  in the inward axial direction  54 , the ramp surfaces  70  of the latch catches  66  engage the latches  90  to flex the latches outwardly from the latching state of  FIG.  4    to the unlatching state of  FIG.  5   . Contact between the surface  70  and the latches  90  allows the latch catches  66  to move inwardly past the latches  90 . Once the retention surfaces  68  of the latch catches  66  move past the retention surfaces  94  of the latches  90 , the latches resiliently return to the latching position of  FIG.  4   . In the latching position of  FIG.  4   , the retention surfaces  68 ,  94  oppose each other such that the connector body  44  is latched within the connector port  24 . Also, the projections  104  fit within the recesses  106  and the ramp surfaces  92 ,  102  oppose each other. The sleeve  50  is in the extended position when the connector  26  is latched within the port  24 . 
     To remove the connector  26  from the port  24 , the release sleeve  50  is pulled in the outward axial direction  56  to move the release sleeve  50  axially relative to the connector body  44  from the extended position to the retracted position. As the release sleeve  50  is pulled from the extended position to the retracted position, the ramp surfaces  102  engage the ramp surfaces  92  to cause the latches  90  to flex from the latching state to the unlatched state. In the unlatched state, the stop surface  94 ,  68  do not oppose or interfere with one another such that the connector  26  can be withdrawn without interference from the latches  90 . Once the connector  26  is withdrawn, the latches  90  resiliently return to the latching state. 
       FIGS.  6 - 11    depict another push-pull fiber optic connection system  120  in accordance with the principles of the present disclosure. The system includes structure  122  (e.g., an adapter, see  FIGS.  6  and  7   ) defining a connector port  124 . The system  120  also includes a fiber optic connector  126  (see  FIGS.  6  and  8   ) including a connector body  144  defining a plug portion  146  sized and shaped for insertion into the connector port  124 . The fiber optic connector  126  also including a release sleeve  150  that is axially moveable relative to the connector body  144 . The plug portion  146  can be temporarily protected by a dust cap  147  prior to insertion in the connector port  124  (see  FIG.  9   ). Similar to the previous example, the structure  122  can be secured within an opening defined by a wall of an enclosure and can be sealed with respect to the enclosure at an outer surface of the enclosure by an o-ring or other type of seal (e.g., a seal can be compressed between the outer surface of the enclosure and an outer flange of the structure  122 ). 
     A latching arrangement  149  is provided for securing the fiber optic connector  126  in the connector port  124 . The latching arrangement  149  is configured to automatically latch the connector body  144  within the connector port  124  when the fiber optic connector  126  is pushed into the connector port  124  in an inward axial direction  125  ( FIG.  10   ).  FIG.  10    shows the latching arrangement  149  in the latching/latched state. The latching arrangement  149  is configured to unlatch when the release sleeve  150  is pulled in an outward axial direction  127  ( FIG.  11   ) while the connector body  144  is latched within the connector port  124  to allow the fiber optic connector  126  to be withdrawn in the outward axial direction  127  from the connector port  124 . 
     The release sleeve  150  is axially moveable relative to the connector body  144  between an extended position (see  FIG.  10   ) and a retracted position (see  FIG.  11   ). A stop arrangement can be used to limit a range of axial travel of the release sleeve  150 . The latching arrangement  149  includes resilient latches  190  integrated with the connector body  144  and latch catches  166  provided at the connector port  124 . It will be appreciated that similar latch catches  166  can be provided in the dust cap  147  for securing the fiber optic connector  126  to the dust cap  147  by a push-pull connection. The latches  190  engage the latch catches  166  to retain the connector body  144  in the connector port  124 . The latch catches  166  are defined by openings  167  through the surface defining the connector port  124 , and include retention surfaces  168 . The latches  190  include retention surfaces  194  that oppose the retention surfaces  168  when the connector body  144  is latched in the connector port  124 . The release sleeve  150  defines openings  161  through which the retention surfaces  194  extend when the connector body  144  is latched in the connector port  124 . Release surfaces  196  are provided on the release sleeve  150  at the openings  161 . The release surfaces  196  oppose ramp surfaces  197  of the latches  190  when the connector body  144  is latched in the connector port  124 . The release sleeve  150  is in the extend position when the connector  126  is latched within the connector port  124 . 
     A first seal  200  is provided for sealing between the connector body  144  and the release sleeve  150 . A second seal  202  is provided for sealing between the structure defining the connector port  124  and the release sleeve  150  when the fiber optic connector  126  is latched within the connector port  124 . The second seal  202  seals against the structure defining the connector port  124  at a position located outside the latching arrangement  149  when the connector body  144  is latched within the connector port  124 . In another example, the seal  202  can be positioned on the connector body  144  inward of the latches  190  so as to be capable of sealing with respect to the connector port  124  at a location inward with respect to the latching arrangement  149 . 
     When the connector  126  is pushed into the connector port  124  in the inward axial direction  125 , the ramp surfaces  197  of the latches  190  engage surfaces  191  in the port  124  to cause the latches  190  to flex inwardly from the latching state of  FIG.  10    to the unlatching/unlatched state of  FIG.  11   . This allows the retention surfaces  194  to move inwardly past the retention surface  168 . Once the retention surfaces  194  of the latches move past the retention surfaces  168  of the catches  166 , the latches resiliently return to the latching position of  FIG.  10   . In the latching position of  FIG.  10   , the retention surfaces  168 ,  194  oppose each other such that the connector body  144  is latched within the connector port  124 . Also, retention surfaces  194  extend through the openings  161  of the release sleeve  150  and the release surfaces  196  oppose the ramp surfaces  197 . The sleeve  150  is in the extended position when the connector  126  is latched within the port  124 . 
     To remove the connector  126  from the port  124 , the release sleeve  150  is pulled in the outward axial direction  127  to move the release sleeve  150  axially relative to the connector body  144  from the extended position to the retracted position. As the release sleeve  150  is pulled from the extended position to the retracted position, the release surfaces  196  engage the ramp surfaces  197  to cause the latches  190  to flex from the latching state ( FIG.  10   ) to the unlatched state ( FIG.  11   ). In the unlatched state, the stop surface  194 ,  168  do not oppose or interfere with one another such that the connector  126  can be withdrawn without interference between the latches  190  and the retaining surfaces  168 . Once the connector  126  is withdrawn, the latches  190  resiliently return to the latching state. 
     Referring now to  FIGS.  12 - 17   , a shroud assembly  210 ,  230  can be mounted over any of the connectors disclosed herein to enable the connector to mate with a different type of adapter. In  FIGS.  12 - 17   , example shroud assemblies are shown with the connector  126  of  FIGS.  6 - 11   . In other examples, however, the shroud assemblies can be mounted over the connector  26  or another push-pull fiber optic connector. For example, the shroud assemblies  210 ,  230  may adapt the connector  126  to form a ruggedized connection with the different type of adapter. As the term is used herein, a “ruggedized connection” refers to an environmentally sealed connection between the connector  126  and the adapter. A “ruggedized connection” also indicates a robust mechanical fastening, such as a twist-to-lock connection (e.g., a bayonet or threaded type connection) or a robust snap-fit connection, between the connector  126  and the adapter. 
     The shroud assembly  210 ,  230  defines a through-passage extending between opposite first and second open ends of the shroud  210 ,  230 . The through-passage is sized to receive at least the plug portion  146  of the connector body  144 . In particular, the plug portion  146  is inserted into the through-passage through the open first end  212 ,  232 . The plug portion  146  extends through the shroud  210 ,  230  so that a ferrule tip of the plug portion  146  is accessible at the second end  214 ,  234  of the through-passage. The shroud assembly  210 ,  230  includes a mechanical securement structure  224 ,  244  to hold the shroud assembly  210 ,  230  to an adapter. In one example, the mechanical securement structure  224 ,  244  includes a twist to lock connection such as a bayonet or threaded type connection. 
     The shroud assembly  210 ,  230  also is configured to engage the connector  126  to retain at least a portion of the shroud assembly  210 ,  230  on the connector  126  in a fixed axial position. In certain examples, the latches  190  of the connector  126  are disposed within the through-passage when the shroud assembly  210 ,  230  is mounted over the connector  126  (e.g., see  FIGS.  14  and  17   ). The latches  190  snap-fit over catch surfaces  220 ,  240  at a rearward end of the shroud assembly  210 ,  230  to axially retain the shroud assembly  210 ,  230  on the connector  126 . 
     In certain implementations, the second seal  202  of the connector  126  also is disposed within the through-passage of the shroud  210 ,  230 . The shroud assembly  210 ,  230  defines a seal engagement surface  222 ,  242  that engages the second seal  202  when the shroud assembly  210 ,  230  is mounted over the connector  126 . 
       FIGS.  12 - 14    illustrate a first type of shroud assembly  210  being utilized in connection with the connector  126 . The first shroud assembly  210  has an outer housing  216  and an inner housing  218  that are axially and rotationally movable relative to each other. The outer housing  216  carries the securement structure  224 . In the example shown in  FIG.  14   , the mechanical securement structure  224  of the first shroud  210  includes a bayonet pin configured to slide along a retention slot defined by the corresponding adapter. The inner housing  218  of the first shroud  210  defines the catch surfaces  220  for the connector latch  190 . The inner housing  218  also defines the seal engagement surface  222 . In certain implementations, the inner housing  218  can include notches, extensions, or the like for providing keying and/or intermateability with respect to the corresponding adapter. For example, such notches and/or extensions can be disposed at the second end  214  of the shroud  210 . 
       FIGS.  15 - 17    illustrate a second type of shroud assembly  230  being utilized in connection with the connector  126 . The second shroud assembly  230  has an outer housing  236  and an inner housing  238  (e.g., see  FIG.  16   ). The outer housing  236  of the second shroud assembly  230  includes a fastener that is axially and rotatably movable relative to the inner housing  238 . The inner housing  238  of the second shroud  230  defines the catch surfaces  240  for the connector latch  190 . The inner housing  238  also defines the seal engagement surface  242 . 
     The outer housing  236  carries the securement structure  244 . In the example shown in  FIG.  16   , the mechanical securement structure  244  of the second shroud  230  includes outwardly facing threads configured to mate with inwardly facing threads of the corresponding adapter. In other examples, the threads  244  of the second shroud  230  can be inwardly facing instead. In certain examples, the inner housing  238  carries an outer seal  246  that seals to the adapter. In certain examples, the inner housing  238  defines extensions  248  to protect the end face of the connector  126 . 
     Having described the preferred aspects and implementations of the present disclosure, modifications and equivalents of the disclosed concepts may readily occur to one skilled in the art. However, it is intended that such modifications and equivalents be included within the scope of the claims which are appended hereto.