Abstract:
A new apparatus for facilitating connections between fiber optic cables. A fiber optic cable assembly having a retainer ring, a spring, and clip attaches a fiber optic cable to an ITA or receiver connector housing. An alignment sleeve assembly having an alignment sleeve housing, and alignment sleeve, and a clip attaches between the faces of a receiver module and an ITA module when they are mated. The receiver or ITA module includes a module support bracket and spring assembly for separating the travel and force required for mating the fiber optic cables from the force and travel required for mating a receiver and ITA.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]    The present application is a related to and claims priority to U.S. Provisional Patent Application Serial No. 60/186,746. 
     
    
     
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
         [0002]    Not applicable.  
         BACKGROUND OF THE INVENTION  
         [0003]    1. Field of the Invention  
           [0004]    The present invention relates to fiber optic connectors and mass interconnect or interface devices. More particularly, the invention relates to a new and novel assembly for a fiber optic connector that increases the cycle life of that fiber optic connector when used in a mass interconnect device.  
           [0005]    2. Description of the Related Art  
           [0006]    An interface or mass interconnect device includes a receiver and an ITA that are mated together to form connections between connectors mounted in modules in the receiver and ITA. An example of one such mass interconnect or interface device is disclosed in U.S. Pat. No. 4,329,005. Commercially available examples of such interface devices include, but are not limited to, Virginia Panel Corporation&#39;s Series 90 and Gemini interface devices. In such interface devices, it has often been desirable to include multiple types of electrical connectors in a single interface. To do so, one may incorporate separate modules for each type of connector or may create modules that accommodate multiple types of connectors.  
           [0007]    Due to recent advances in technology, it has become desirable to include fiber optic connectors in such interface devices. Including both fiber optic connectors and electrical connectors together in a single interface device, however, has raised new problems. One such problem is that fiber optic connectors require a shorter travel distance to make a connection than do some other types of connectors. When fiber optic connectors are used in an interface device with other types of connectors, this difference in required travel distances can result in unnecessarily strong forces being applied to the tips of the fiber optic cables being connected. Such unnecessarily high forces can cause damage to the tips of the fiber optic cables. Further, some fiber optic connectors require axial positioning, which is not necessary for many other types of connectors.  
           [0008]    Thus, conventional fiber optic connectors suffer from the problems of having limited cycle lives between polishings and/or limited repolishings before needing to be replaced. Connectors such as the M29504 type termini, which have a two thousand mating cycle specification, have only a very limited amount of travel (0.030″) for the termini to work. This limited travel reduces the number of times the termini can be repolished before needing to be replaced. These termini additionally suffer from the problems of high cost and difficulty in obtaining good termini performance.  
           [0009]    In contrast, termini having significant travel (0.090″), such as a TFOCA type termini, have a five hundred mating cycle specification, but they can be re-polished and then work for another 500 cycles. By observing the termini tip under a microscope, however, the inventors have found that the fiber-cladding, material that surrounds the core of the optical fiber, was flaking apart and thereby making the termini fail. The cladding fails due to material surface fatigue, like a bearing surface without lubrication.  
           [0010]    During the connector mating the two termini surfaces are in contact and exposed to limited motion perpendicular to the termini axis. During this motion, point contacts are created with a significant force (1.5 lb) applied at the same time. This causes very localized high surface pressure that results in the fiber-cladding material failure.  
         SUMMARY OF THE INVENTION  
         [0011]    The present invention has been made in view of the above circumstances and has as an object to provide a fiber optic cable assembly that can increase the number of cycles the termini of a fiber optic connector may be used without re-polishing. The present invention allows the use of a termini such as the TFOCA type termini for about 4000 cycles without re-polishing. The present invention achieves this result by separating the required travel and force for the termini to be in contact with 1.5 lb load from the interface clamping travel and force. By doing this, the invention eliminates the termini motions during the clamping action.  
           [0012]    A further object of the invention is to provide a cable clip attachment for a module to allow easy installation, inspection, cleaning and replacement of any cable on the module. The cable clips of the invention also position and prevent the termini from rotating inside the module. The present invention uses only one part (the clip) to secure and position (angularly and axially) the termini compared to prior devices that uses about 3 parts.  
           [0013]    Additional objects and advantages of the invention will be set forth in part in the description which follows and in part will be obvious from the description, or may be learned by practice of the invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    The accompanying drawings, which are incorporated in and constitute a part of this specification illustrate some embodiments of the invention and, together with the description, serve to explain the objects, advantages, and principles of the invention. In the drawings,  
         [0015]    FIGS.  1 ( a ), ( b ) and ( c ) are bottom, side, and end views of a receiver module assembly of one embodiment of the present invention.  
         [0016]    FIGS.  2 ( a ) and ( b ) are top and side views of a connector stop of the present invention.  
         [0017]    FIGS.  3 ( a ), ( b ), and ( c ) cross-sectional, bottom, and end views of a connector module cover of the present invention.  
         [0018]    FIGS.  4 ( a ), ( b ), and ( c ) are bottom, side, and end views of an ITA module assembly of one embodiment of the present invention.  
         [0019]    FIGS.  5 ( a ) and ( b ) are side and top views of a module guide pin of the present invention.  
         [0020]    FIGS.  6 ( a ), ( b ), and ( c ) are top, side, and front views of module support bracket of the present invention.  
         [0021]    FIGS.  7 ( a ), ( b ), and ( c ) are side, top, and cross-sectional views of an alignment sleeve assembly of the present invention.  
         [0022]    FIGS.  8 ( a ), ( b ), and ( c ) are side, top, and cross-sectional views of an alignment sleeve housing of the present invention.  
         [0023]    FIGS.  9 ( a ), ( b ), and ( c ) are side, top, and cross-sectional views of an alignment sleeve retainer clip of the present invention.  
         [0024]    FIGS.  10 ( a ) and ( b ) are top and side views of an alignment sleeve retainer clip of the present invention during a production stage.  
         [0025]    [0025]FIG. 11 is a diagram of a fiber optic cable assembly of the present invention.  
         [0026]    FIGS.  12 ( a ) and ( b ) are top and side views of a termini sub-assembly of the present invention.  
         [0027]    FIGS.  13 ( a ), ( b ), and ( c ) are top, side, and cross-sectional views of a termini retainer clip for a fiber optic cable assembly of the present invention.  
         [0028]    FIGS.  14 ( a ), ( b ), and ( c ) are top, side, and cross-sectional views of a second embodiment of a termini retainer clip for a fiber optic cable assembly of the present invention.  
         [0029]    FIGS.  15 ( a ) and ( b ) are top and side views of a termini retainer clip of the present invention during a production stage.  
         [0030]    FIGS.  16 ( a ), ( b ), and ( c ) are front, side, and detail views of a retainer clip removal tool for use with the present invention.  
         [0031]    FIGS.  17 ( a ) and ( b ) are top and side views of a clip removal tool during a production stage.  
         [0032]    [0032]FIG. 18 is a perspective view of a fiber optic cable assembly of the present invention being inserted into a receiver module housing of the present invention.  
         [0033]    [0033]FIG. 19 is a perspective view of an alignment sleeve assembly of the present invention being connected, to a receiver module assembly of the present invention.  
         [0034]    [0034]FIG. 20 is a perspective view of a receiver module assembly, fiber optic cable assembly, and alignment sleeve assembly of the present invention.  
         [0035]    [0035]FIG. 21 is a perspective view of an alignment sleeve assembly of the present invention being removed from a receiver module assembly in one embodiment of the present invention.  
         [0036]    [0036]FIG. 22 is a perspective view of a fiber optic cable assembly being inserted into an ITA module assembly in one embodiment of the present invention.  
         [0037]    [0037]FIG. 23 is a perspective view of a fiber optic cable assembly assembled together with an ITA module assembly in one embodiment of the present invention.  
         [0038]    [0038]FIG. 24 is a perspective view of a fiber optic cable assembly being removed from an ITA module assembly in one embodiment of the present invention.  
         [0039]    [0039]FIG. 25 is a side view of a mated receiver and ITA module pair with a fiber optic patch cord assembly in one embodiment of the present invention.  
         [0040]    [0040]FIG. 26 is a side view of a receiver module assembly in a second embodiment of the invention.  
         [0041]    [0041]FIG. 27 is a side view of an ITA module assembly in a second embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0042]    A receiver module assembly of the present invention is described with reference to FIGS.  1 ( a ), ( b ), and ( c ). The receiver module assembly  10  includes a receiver connector housing  12  having a plurality of openings  14  for receiving connectors. An alignment pin  16  projects from the face  18  of connector housing  12  at each of its two ends. A connector stop  20  surrounds the base of each of the two pins  16 . The stop  20  is shown in greater detail in FIGS.  2 ( a ) and ( b ). The stop  20  has a cylindrical wall  202  and an opening  204  throughout its center for receiving a guide pin  16 . The stop  20 , of course, could be formed in other shapes. The receiver connector housing  12  further includes on each side near its face  18  a ridge  22  for receiving a clip  56 . The receiver module assembly further includes on each of its sides a ridge  24  near the back side  25  of the connector housing  12 . A connector module cover  27 , shown in FIGS.  3 ( a ), ( b ), and ( c ) may be placed over the face of the receiver connector housing to protect the fiber optic cables when not mated to an interface test adapter. The connector module cover  27  includes a housing  272  having a closed face  274  and an open face  276 . A tab  278  protrudes from the closed face  274  at each end of the connector module cover  27 . The interior of the connector module cover  27  may include a series of ribs  275 .  
         [0043]    An ITA module assembly  30  is described with reference to FIGS.  4 ( a ), ( b ), and ( c ). The ITA module assembly  30  comprises an ITA connector housing  32  having a plurality of openings  34  for receiving for receiving connectors. The ITA connector housing  32  has a hole  36  at each end for receiving a pin  16  in the receiver module assembly  10 . The ITA connector housing  32  further has a hole with a module guide pin  33  therein near each end. The module guide pin  330  is shown in greater detail in FIGS.  5 ( a ) and ( b ). The module guide pin has a cylindrical wall  332 , which a protrusion  334  around its circumference near one end and an groove around its circumference near the other end. The module guide pin has a hole  338  extending from top to bottom. The ITA module assembly further comprises a ITA module spring assembly  38 , shown in FIG. 4( c ), for securing the ITA module assembly  30  to the receiver module assembly  10  when they are mated. The ITA module spring assembly  38  comprises a shoulder screw or guidepost  48 , a module support bracket  31 , and a spring  39 . The module support bracket  31  is shown in greater detail in FIGS.  6 ( a ), ( b ), and ( c ). The module support bracket  31  includes a base  310  and two sides  312 . The base  310  includes a hole  314  for receiving a guidepost  48 . The ITA connector housing  32  further has on each side near its face  40  a ridge  42  for receiving a clip. Likewise, the ITA connector housing  32  further has a ridge  44  near the back side  46  of the ITA connector housing  32  for receiving a clip.  
         [0044]    FIGS.  7 ( a ), ( b ), and ( c ) illustrate an alignment sleeve assembly  50 . The alignment sleeve assembly  50  is comprised of an alignment sleeve housing  52 , an alignment sleeve  54 , and a sleeve retainer clip  56 . The alignment sleeve housing  52  is shown in greater detail in FIGS.  8 ( a ), ( b ), and ( c ). The alignment sleeve housing includes a cylindrical side wall  522  having a protrusion or stop  524  around its circumference along a small portion of its length. The center of the alignment sleeve housing  52  is hollow for receiving fiber optic connectors. At one end of the alignment sleeve, a portion  526  of the side walls  522  projects inward toward the center of the housing thereby narrowing the opening at one end of the alignment sleeve housing  52  and creating a step for retaining the alignment sleeve  54  within the alignment sleeve housing  52 . The open end of the alignment sleve housing  52  is tolled over after the alignment sleeve  54  is inserted to retain alignment sleeve  54 . The alignment sleeve retainer clip  56 , shown in greater detail in FIGS.  9 ( a ), ( b ), and ( c ) includes on each of its sides  58  a retainer prong  60  projecting slightly toward the other side of the clip and the base  62  of the clip  56 . The base  62  of the sleeve retainer clip  56  includes a circular hole  55  for receiving the alignment sleeve housing. FIGS.  10 ( a ) and ( b ) show the sleeve retainer clip in a production stage. The alignment sleeve assembly  50  connects to the ITA module assembly  30 . The end of the alignment sleeve housing  50  that projects between the sides of the clip is inserted into the holes in the face  40  of the ITA module assembly. When the alignment sleeve housing  50  is so inserted the sides of the clip extend around the sides of the connector housing  32  and snap onto the ridge  42  on the connector housing  32 , thereby securing the alignment sleeve housing  50  in place on the ITA connector housing.  
         [0045]    A fiber optic cable assembly  70  incorporating the present invention is described with reference to FIG. 11. The same design of fiber optic cable assembly  70  is used on each side of the interface, i.e., the receiver module assembly side and the ITA module assembly side. The fiber optic cable assembly  70  includes a termini subassembly  72 , a fiber optic cable  74 , shrink tubing  76 , and a dust cap  78 . The termini subassembly, shown in FIGS.  12 ( a ) and ( b ) includes a pin or termini body  702 , a spacer  704 , a termini spring  706 , a termini retainer clip  708 , and a retainer ring  710 . In the fiber optic cable assembly  70 , the termini sub assembly  72  is connected to a fiber optic cable  74  using a crimp sleeve  73 . Shrink tubing  76  is placed over the crimp sleeve  73  and extends beyond the crimp sleeve on each end to respectively cover a portion of the fiber optic cable  74  and a portion of the pin body  702 . The termini spring  706  biases the termini retainer clip  708  away from ferrule or tip  705  of the termini body  702 . When the fiber optic cable assembly is not in use, a dust cap  78  may be placed over the ferrule or tip  705  of the termini body  702  to protect the fiber optic cable end. The dust cap  78  may be connected to the fiber optic cable assembly  70  with, for example, a plastic strip  79  to prevent loss of the cover when the fiber optic cable assembly is in use.  
         [0046]    A first preferred embodiment of the termini retainer clip  708  is shown in detail in FIGS.  13 ( a ), ( b ), and ( c ). The clip includes a base  82  and two sides  84  extending from the base  82 . Each side  84  includes a retainer prong  86  projecting slightly toward the center of the clip and toward the base  82  and an opening  90  above each retainer prong  86 . The base  32  of the clip has a D-shaped hole  88  for receiving a termini body  702 . Also shown in FIG. 4 is a dust cover  75 .  
         [0047]    In a second preferred embodiment of the retainer clip, shown in FIGS.  14 ( a ), ( b ), and ( c ), the termini retainer clip further includes a tab  85  for ensuring proper installation of the fiber optic cable assembly into the receiver or ITA module connector housing  12  or  32 . FIGS.  15 ( a ) and ( b ) show the termini retainer clip  708  during a production stage. When using this embodiment, the back side  46  of the receiver or ITA module connector housing  12  or  32  includes a groove (not shown) on one side for receiving the tab  85  on termini retainer clip  708 . In this manner, an operator can easily determine the correct orientation of the termini sub assembly with respect to the receiver or ITA module connector housing  12  or  32 .  
         [0048]    Many other alternative embodiments would be apparent to one skilled in the art from the above disclosure. For example, the structures of the receiver module assembly of FIGS.  1 ( a ), ( b ) and ( c ) and the ITA module assembly of FIGS.  4 ( a ),( b ), and ( c ) could be switched such that the receiver module assembly would include the module support bracket while the ITA module assembly would not. FIGS. 26 and 27 depict such an alternative embodiment.  
         [0049]    An alternative embodiment of a receiver module assembly  800  is described with reference to FIG. 26. The receiver module assembly  800  comprises a receiver connector housing  832  having a plurality of openings  834  (not shown) for receiving connectors. The receiver connector housing  832  has a pin  816  in the ITA module assembly  810  shown in FIG. 27. An alignment pin  816  projects from the face  840  of connector housing  832  at each of its two ends. A connector stop  20  surrounds the base of each of the two pins  816 . The receiver module assembly  800  further comprises a receiver module spring assembly  838 , with similar structure to that shown in FIG. 4( c ), for securing the receiver module assembly  800  to the ITA module assembly  850 , shown in FIG. 27, when they are mated. The receiver module spring assembly  838  comprises a shoulder screw or guidepost  848 , a module support bracket  831 , and a spring  839  (not shown). The module support bracket  831  includes a base and two sides. The base includes a hole for receiving a guidepost. The receiver connector housing  832  further has on each side near its face  840  a ridge  842  for receiving a clip. Likewise, the receiver connector housing  832  further has a ridge  844  near the back side  846  of the receiver connector housing  832  for receiving a clip.  
         [0050]    An alternative embodiment of an ITA module assembly of the present invention is described with reference to FIG. 27. The ITA module assembly  810  includes an ITA connector housing  812  having a plurality of openings  814  (not shown) for receiving connectors. The ITA connector housing  812  further includes on each side near its face  818  a ridge  22  for receiving a clip  56 . The receiver module assembly further includes on each of its sides a ridge  824  near the back side  825  of the connector housing  812 .  
         [0051]    A fiber optic cable assembly  70  is mounted on a receiver module assembly  800  by inserting the fiber optic cable  74  and connector  76  into the openings in the back side  846  of the receiver module assembly  800  such that the cable  74  projects slightly from the face  840  of the receiver module connector housing  832  as shown in FIGS. 18 and 20. When so inserted, the retainer prongs  86  on the clip  80  snap onto the ridge  844  near the back side  846  of the receiver module housing  832 . The alignment sleeve assembly is inserted into the face of a receiver module housing  832  as shown in FIG. 19.  
         [0052]    A fiber optic connector assembly is mounted on an ITA module assembly  850  by inserting the fiber optic cable  74  and the connector  76  into the holes in the back side  825  of the ITA connector housing  812  as shown in FIGS.  22 - 23 . When the fiber optic connector  76  is so inserted, the retainer prongs  86  on the clip  80  snap onto the ridge  824  near the back side  825  of the ITA connector housing  812 .  
         [0053]    The ITA module assembly  850  is then mated to the receiver module assembly  800  to form a fiber optic connection, as shown in FIG. 25. To mate the two assemblies, the pins  16  extending from the face of the receiver module assembly  800  are aligned with and inserted into the holes  836  in the face  818  of the ITA module connector housing  812 . As the receiver and ITA module assemblies  800  and  850  are pushed together, the fiber optic connectors  76  extending slightly from the face of the ITA module assembly  850  enter into the alignment sleeve housing  50  and align with the fiber optic cables  76  in the receiver module assembly  32 .  
         [0054]    To remove a fiber optic cable assembly from either an ITA module or a receiver module, a simple clip removal tool  90 , shown in FIGS.  16 ( a ), ( b ), and ( c ) tool may be used, as shown in FIGS. 21 and 24. The crimp removal tool may be formed from a metal strip  92 , such as stainless steel, having a wide center portion  94  and narrow ends  96 , as shown in FIGS.  17 ( a ) and ( b ). The metal strip  92  is bent to form a v-shape with two sides  98  and a rounded base  100  as shown in FIG. 16( a ). Each side  98  is further bent or formed to include and indentation  982  near the middle of the side and a hook  984  at the end of the side. To remove a fiber optic cable assembly from a module, the clip removal tool is placed over the fiber optic cable assembly and the sides of the clip removal tool are manually compressed to position the hoods  984  on the clip removal tool  90  over the edges of the termini retainer clip. When the sides of the clip removal tool are released, the hooks  984  at the ends of the sides of the clip removal tool pull the sides of the termini retainer clip away from the connector module housing thereby releasing the tabs on the termini retainer clip from the ridge on the connector housing. The fiber optic cable assembly may then be removed from the connector housing.  
         [0055]    The foregoing description of the preferred embodiment of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of the invention. The embodiment was chosen and described in order to explain the principles of the invention and its practical application to enable one skilled in the art to utilize the invention in various embodiments as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto, and their equivalents.