Abstract:
Connectorizing an optical fiber cable includes mounting at least part of a connector housing about a ferrule assembly; positioning a crimp sleeve so that a distal section of the crimp sleeve is disposed about a proximal end of the connector housing and a proximal section of the crimp sleeve is disposed about a jacketed portion of the optical fiber cable; applying a first force to the distal section of the crimp sleeve to tighten the distal section of the crimp sleeve against the proximal end of the connector housing; and applying a second force to the proximal section of the crimp sleeve to tighten the proximal section of the crimp sleeve against the jacketed portion of the optical fiber cable. Adhesive may be added to the proximal section of the crimp sleeve through an aperture.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/874,567 filed on Sep. 6, 2013, and titled “Optical Fiber Connector and Cable Assembly with Dual Diameter Crimp Sleeve,” the disclosure of which is hereby incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    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. 
         [0003]    A number of factors are important with respect to the design of a fiber optic connector. One such factor relates to the ability to effectively anchor a connector to a cable to prevent or minimize signal degradation resulting from a pulled cable. 
       SUMMARY 
       [0004]    Aspects of this disclosure are directed to connectorizing an optical cable assembly with a connector having a crimp sleeve with a varying diameter and an adhesive aperture. 
         [0005]    In accordance with some aspects of the disclosure, the crimp sleeve enables secure connection of cable strength members to a connector. In accordance with other aspects of the disclosure, one crimp sleeve can accommodate cables of various diameters. 
         [0006]    In some implementations, connectorizing the optical fiber cable includes coupling a ferrule assembly to a first optical fiber of the optical fiber cable; mounting at least part of a connector housing about the ferrule assembly; positioning a crimp sleeve so that a distal section of the crimp sleeve is disposed about a proximal end of the connector housing and a proximal section of the crimp sleeve is disposed about a jacketed portion of the optical fiber cable; applying a first force to the distal section of the crimp sleeve to tighten the distal section of the crimp sleeve against the proximal end of the connector housing; applying a second force to the proximal section of the crimp sleeve to tighten the proximal section of the crimp sleeve against the jacketed portion of the optical fiber cable; and applying adhesive into an aperture defined in the proximal section of the crimp sleeve to enhance retention of the jacketed portion of the optical fiber cable within the proximal section of the crimp sleeve. The crimp at the proximal section controls the flow of adhesive to inhibit contact between the adhesive and the optical fiber of the cable. 
         [0007]    In some implementations, an example optical cable and connector assembly includes an optical cable including at least a first optical fiber disposed within a cable jacket; a connector housing including a proximal housing and a distal housing that couple together; a ferrule assembly disposed in the connector housing; and a crimp sleeve. The crimp sleeve has a proximal section and a distal section. The distal section has a first internal cross-dimension and the proximal section has a second internal cross-dimension. The distal section of the crimp sleeve tightly crimps cable strength members to the proximal end of the proximal housing of the connector housing. The proximal section of the crimp sleeve is adhered to the cable jacket. 
         [0008]    In certain implementations, the proximal section of the crimp sleeve is loosely crimped to the cable jacket. In certain implementations, the first internal cross-dimension is larger than the second internal cross-dimension. 
         [0009]    In accordance with aspects of the disclosure, an example crimp sleeve includes a distal section including a first circumferential wall having a first internal cross-dimension; a proximal section including a second circumferential wall having a second internal cross-dimension; and a transition section including a third circumferential wall extending between the distal section and the proximal section. The second internal cross-dimension is smaller than the first internal cross-dimension. The third circumferential wall tapers between the first internal cross-dimension and the second internal cross-dimension. The first, second, and third circumferential walls cooperate to define an internal bore that extends along a longitudinal axis of the crimp sleeve. The second circumferential wall defines an aperture. 
         [0010]    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 
         [0011]    The accompanying drawings, which are incorporated in and constitute a part of the description, illustrate several aspects of the present disclosure. A brief description of the drawings is as follows: 
           [0012]      FIG. 1  is a perspective view of an example optical connector and cable assembly including an optical cable terminated by an optical connector in accordance with the principles of the present disclosure; 
           [0013]      FIG. 2  is a cross-sectional view of an example cable assembly including a ferrule assembly terminating an optical fiber cable; 
           [0014]      FIG. 3  is a cross-sectional view of an example connector housing mounted over the cable assembly of  FIG. 2 ; 
           [0015]      FIG. 4  is a cross-sectional view of an example crimp sleeve mounted over the connector housing and the cable assembly of  FIG. 3 ; 
           [0016]      FIG. 5  is a perspective view of the example crimp sleeve of  FIG. 4 ; 
           [0017]      FIG. 6  is a longitudinal cross-section of the crimp sleeve of  FIG. 5 ; 
           [0018]      FIG. 7  is a cross-sectional view of an example strain-relief boot mounted over the crimp sleeve and connector housing of  FIG. 4 ; and 
           [0019]      FIG. 8  is a cross-sectional view of an example release sleeve mounted over the connector housing and the cable assembly of  FIG. 7 . 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    Reference will now be made in detail to exemplary aspects of the present disclosure that are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
         [0021]      FIG. 1  illustrates one example optical connector and cable assembly  100  including an optical cable  110  terminated by an optical connector  105 . In the example shown, the optical connector  105  is an SC connector. However, the principles of the present disclosure can be applied to other types of optical connectors (e.g., LC connectors, ST connectors, FC connectors, LX.5 connectors, etc.). In the example shown, the connector  105  terminates a single optical fiber  116 . In other implementations, however, the connector can terminate a multi-fiber cable. 
         [0022]    In accordance with some aspects of the disclosure, the same connector  105  can be applied to various cables having different transverse cross-dimensions (e.g., cable diameters). In an example, the optical connector  105  can terminate an optical fiber cable  110  having a transverse cross-dimension of two millimeters. In another example, the optical connector  105  can terminate an optical fiber cable  110  having a transverse cross-dimension of three millimeters. 
         [0023]    As shown in  FIG. 2 , the optical cable  110  includes an optical fiber  116  and strength members (e.g., aramid yarns)  115  surrounded by a cable jacket  112 . In certain implementations, a buffer tube  114  is disposed between the optical fiber  116  and the strength members  115 . The optical fiber  116  is coupled to a ferrule  122 . In some implementations, a distal end of the optical fiber  116  is held by the ferrule  122 . In other implementations, the distal end of the optical fiber  116  is spliced to a ferrule stub  124  of a ferrule assembly  120 . In some such implementations, the ferrule assembly  120  includes a ferrule hub  124  disposed over the splice location  128 . An example ferrule hub  124  can include a rear hub portion  128  overmolded to a flange  126 . The ferrule hub  124  can be disposed about the buffer tube  114  of the cable  110  to protect the fiber  116 . 
         [0024]    As shown in  FIG. 3 , a connector housing  130  can be assembled over the ferrule assembly  120 . In the example shown, the connector housing  130  includes a distal housing  132  and a proximal housing  134 . The distal and proximal housings  132 ,  134  cooperate to define a cavity  135  in which the ferrule assembly  120  and a spring  138  can be disposed. One end of the spring  138  abuts an inner surface of the proximal housing  134  and the other end of the spring  138  abuts the ferrule assembly  120  to bias the ferrule  122  outwardly from the distal housing  132 . 
         [0025]    As shown in  FIG. 4 , the connector housing  130  is secured to the cable  110  using a crimp sleeve  140 . The crimp sleeve  140  includes a distal section  141  and a proximal section  145 . The distal section  141  of the crimp sleeve  140  can be crimped over a proximal end  139  of the proximal housing  134  of the connector housing  130 . The strength members  115  of the cable  110  can be retained between the crimp sleeve distal section  141  and the proximal connector housing  134 . Crimping the strength members  115  to the connector housing  130  anchors the cable  110  to the connector housing  130 . 
         [0026]    In accordance with certain aspects of the disclosure, the proximal section  145  of the crimp sleeve  140  can be adhered to the cable jacket  112  of the cable  110 . In certain implementations, the cable jacket  112  extends partially into the crimp sleeve  140 . In the example shown, the cable jacket  112  terminates at a transition section  143  ( FIG. 5 ) of the crimp sleeve  140 . In other implementations, the cable jacket  112  can extend a greater or lesser distance into the crimp sleeve  140 . Adhesive (e.g., a cyanoacrylate, an epoxy, a resin, etc.) can be added between the proximal section  145  of the crimp sleeve  140  and the cable jacket  112  to provide retention of the cable  110  at the crimp sleeve  140 . The proximal section  145  of the crimp sleeve  140  defines an aperture  147  sized to receive an injection of adhesive. 
         [0027]    In some implementations, the proximal section  145  of the crimp sleeve  140  can be crimped over the jacket  112  to manage the flow of the adhesive during injection. For example, the crimped proximal section  145  can inhibit the distal flow of adhesive towards the optical fiber  116 . Accordingly, the crimped proximal section  145  can inhibit contact of the optical fiber  116  by the adhesive that would result in signal degradation. In certain implementations, the proximal section  145  is loosely crimped to the cable jacket. 
         [0028]    The combination of the loose crimp and the adhesive allows the connector  115  to terminate cables  110  of different transverse cross-dimensions. The crimp sleeve proximal section  145  is tightened until the proximal section  145  bears against the cable jacket  112 . Accordingly, the proximal section  145  would be squeezed a first amount to crimp over a first cable having a first cross-dimension and would be squeezed a second, different amount to crimp over a second cable having a second cross-dimension. The adhesive enables the crimp to be loose since the adhesive provides the necessary retention. The loose crimp inhibits crushing or otherwise damaging the optical fiber  116 . 
         [0029]      FIGS. 5 and 6  illustrate one example crimp sleeve  140  suitable for use in connecting the connector housing  130  to the cable  110 . The distal section  141  of the crimp sleeve  140  includes a first circumferential wall  142  and the proximal section  145  of the crimp sleeve  140  includes a second circumferential wall  146 . A transition section  143  includes a third circumferential wall  144  extending between the distal section  141  and the proximal section  145 . The first, second, and third circumferential walls  142 ,  146 ,  144 , respectively, cooperate to define an internal bore  148  that extends along a longitudinal axis of the crimp sleeve  140 . As shown in  FIG. 6 , the bore  148  through the proximal crimp sleeve  140  tapers outwardly (i.e., the circumferential wall  146  becomes narrower). The tapered wall  146  facilitates threading the cable  110  through the crimp sleeve  140 . 
         [0030]    In accordance with some aspects of the disclosure, the crimp sleeve  140  is pre-formed as a dual-diameter crimp sleeve  140 . For example, the first circumferential wall  142  has a first internal cross-dimension D 1  and the second circumferential wall  146  has a second internal cross-dimension D 2  when uncrimped. The third circumferential wall  144  tapers radially between the first and second walls  142 ,  146 . In certain implementations, the second internal cross-dimension D 2  is smaller than the first internal cross-dimension D 1 . In other implementations, the cross-dimensions D 1 , D 2  are initially the same and vary during the crimping process. 
         [0031]    The aperture  147  extends from an exterior of the crimp sleeve  140 , through the circumferential wall  146  of the proximal section  145 , to the bore  148 . In some implementations, the aperture  147  extends along at least about 25% of a circumference of the proximal section  145  of the crimp sleeve  140 . In certain implementations, the aperture  147  extends along about 33% of the circumference of the proximal section  145  of the crimp sleeve  140 . In certain implementations, the aperture  147  extends along no more than about 50% of the circumference of the proximal section  145  of the crimp sleeve  140 . 
         [0032]    As shown in  FIG. 7 , a strain-relief boot  150  can be coupled to the connector housing  130  to provide strain-relief to the optical fiber  116  extending out of the proximal end of the connector housing  130 . The boot  150  defines a passage  152  through which the optical cable  110  can pass. The boot  150  has a flexible section F that extends over a portion of the optical cable  110  to inhibit excessive bending of the cable portion. The flexible section F of the boot  150  defines slots, notches, or other structure to enhance flexing of the flexible section F relative to a remainder of the boot  150 . 
         [0033]    The boot  150  includes a retention section  151  that extends over the crimp sleeve  140 . A distal end of the retention section  151  includes latching hooks  153  or other such structure that snap over retention structures on the proximal housing  134  to secure the boot  150  to the connector housing  130 . The interior passage  152  of the boot  150  varies in size. The passage  152  has a relatively large cross-dimension around the distal section  141  of the crimp sleeve  140 , a smaller cross-dimension around the proximal section  145  of the crimp sleeve  140 , and an even smaller cross-dimension through the flexible section F. 
         [0034]    As shown in  FIG. 8 , a release sleeve  160  can be mounted over the connector housing  130  to facilitate removal of the connector  105  from an optical adapter or other receptacle port. As shown in  FIG. 1 , the release sleeve  160  surrounds the connector housing  130  and part of the boot  150 . A distal portion  161  of the release sleeve  160  defines openings  162  through which retention structure of the connector housing  130  is accessible. The proximal portion  163  of the release sleeve  160  provides a grip region  164 . The release sleeve  160  also can include a key  165  to mate with a key slot in the optical adapter or other receptacle. 
         [0035]    The above specification, examples and data provide a complete description of the manufacture and use of the composition of the invention. Since many embodiments of the invention can be made without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended.