Abstract:
A fanout connector assembly is provided for fiber optic cables each including a plurality of optical fibers. The assembly includes at least two fanout connectors each having a housing with a passage for receiving a fiber optic cable along an axis. A fanout member in the housing spreads the individual optical fibers of the cable transversely of the axis. Complementary interengaging stacking members on the housings of the two connectors align and hold the connectors in stacked relationship with one connector on top of the other connector. An individual connector includes a base housing and a cover with complementary interengaging strain relief members and complementary interengaging latch members therebetween. The strain relief members and the latch members are respectively interengaged automatically in response to mounting the cover on the base housing, but the strain relief members are at least partially interengaged prior to interengagement of the latch members.

Description:
FIELD OF THE INVENTION 
     This invention generally relates to the art of connector assemblies and, particularly, to a fiber optic connector assembly, but certain features of the invention may be equally applicable for use with other types of connectors such as electrical connectors. 
     BACKGROUND OF THE INVENTION 
     Fiber optic connectors of a wide variety of designs have been employed to terminate optical fiber cables and to facilitate connection of the cables to other cables or other optical fiber transmission devices. A typical fiber optic connector includes a ferrule which mounts and centers an optical fiber or fibers within the connector. The ferrule may be fabricated of such material as ceramics. A multi-fiber optic cable is terminated in the connector, and a plurality of individual optical fibers of the cable may be terminated in the ferrule. A popular type of fiber optic cable is a multi-fiber flat cable which conventionally is called a ribbon cable. 
     One specific type of fiber optic connector is a “fanout” connector which typically is used with a ribbon-type cable. The individual optical fibers of the cable are very closely spaced. A fanout connector includes a fanout means such as a fanout insert for receiving and spreading the individual fibers of the cable transversely thereof so that the fibers are more easily connectorized according to hardware interface requirements. Often, the individual fibers extend away from the fanout insert within a plurality of easily manipulatable tubes which also protect the fibers. The tubes often are color-coded and are permanently affixed to a fanout structure by, for example, heat shrinking. This type of attachment may degrade the temperature cycling performance by causing micro bending of the fibers. The present invention is directed to providing various improvements in connector assemblies, such as fiber optic connector assemblies, including fanout-type fiber optic connectors. 
     SUMMARY OF THE INVENTION 
     An object, therefore, of the invention is to provide a new and improved connector assembly, such as a fiber optic fanout connector, of the character described. 
     In the exemplary embodiment of the invention, a fanout connector assembly is provided for a fiber optic cable including a plurality of optical fibers. The assembly includes at least two fanout connectors each including a housing having a passage for receiving a fiber optic cable along an axis. The housing has a fanout member for spreading the individual optical fibers of the fiber optic cable transversely of the axis. Complementary interengaging stacking members are provided on the housing of the two connectors for aligning and holding the connectors in stacked relationship with one connector on top of the other connector. 
     As disclosed herein, the complementary interengaging stacking members comprise at least one mounting post on the housing of one of the connectors received in a mounting hole in the housing of the other connector. Preferably, a plurality of the mounting posts are received in a plurality of the mounting holes. The posts may be sized relative to the holes for receipt therein by a press-fit. The posts may also be adapted to be press fit into mounting holes in a printed circuit board. 
     According to one aspect of the invention, the housing for each connector includes a base housing and a cover with at least one of the mounting post and the mounting hole being on each of the base housing and cover. Preferably, the base housing and the cover of one connector each includes an upstanding mounting base, and the base housing of the other connector includes a pair of mounting holes for receiving the mounting posts. The cover is shown herein slidably mounted on the base housing generally parallel to the axis, whereby the cover is rendered immovable when the connectors are stacked. 
     According to another aspect of the invention, the base housing and the cover have complementary interengaging latch members for interengagement automatically in response to slidably mounting the cover onto the base housing. Complementary interengaging cable strain relief members also are provided between the base housing and cover for interengagement automatically in response to slidably mounting the cover onto the base housing. Preferably, the latch members and the strain relief members are located relative to each other whereby the strain relief members are at least partially interengaged prior to interengagement of the latch members. 
     Other objects, features and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The features of this invention which are believed to be novel are set forth with particularity in the appended claims. The invention, together with its objects and the advantages thereof, may be best understood by reference to the following description taken in conjunction with the accompanying drawings, in which like reference numerals identify like elements in the figures and in which: 
     FIG. 1 is a top perspective view of a fanout fiber optic connector embodying the concepts of the invention; 
     FIG. 2 is a bottom perspective view of the connector; 
     FIG. 3 is an axial section taken generally along line  3 — 3  of FIG. 1; 
     FIG. 4 is a top, exploded perspective view of the connector; 
     FIG. 5 is a bottom perspective view of the cover of the connector; 
     FIG. 6 is a top perspective view of a pair of the connectors in a stacked relation; 
     FIGS. 7 and 7A are perspective views showing the top weakened areas of the frangible webs for the mounting members; 
     FIGS. 8 and 8A are perspective views showing the bottom weakened areas for the frangible webs of the mounting members; 
     FIGS. 9 and 10 are top and bottom perspective views, respectively, of the base housing with the mounting members being broken-away therefrom; 
     FIG. 11 is a top plan view of the connector, with the cover removed; 
     FIG. 12 is a perspective view similar to the plan view of FIG. 11; 
     FIG. 13 is a perspective view showing the cover initially being assembled to the base housing; 
     FIG. 14 is a view similar to that of FIG. 13, with the cover slidably mounted further onto the base housing but not quite to its final position; 
     FIG. 15 is a side elevational view of the connector, partially in section, to show the interengaged strain relief means and latch means; and 
     FIG. 16 is a perspective view similar to that of FIG. 1, but showing a non-stackable embodiment of the connector. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the drawings in greater detail, and first to FIGS. 14, the invention is embodied in a fanout connector, generally designated  20  and which is fabricated of three major components. As best seen in FIG. 4, those components include a base housing, generally designated  22 , and a cover, generally designated  24 , which is slidably mounted onto the base housing in the direction of arrow “A”. The base housing and cover form a housing means for receiving a third major component, namely a fanout insert, generally designated  26 . A fiber optic cable  28  includes a plurality of individual optical fibers  30  which extend through the fanout insert and through a plurality of tubes  32  projecting forwardly of the insert. 
     More particularly, base housing  22  of fanout connector  20  includes a through passage, generally designated  34 , for receiving cable  28  and fibers  30  along an axis  36 . The base housing is a one-piece structure unitarily molded of plastic material and includes a bottom wall  38  and a pair of upstanding side walls  40  which define a receptacle  42  which communicates with or is a part of through passage  34 . The receptacle generally is at a front end  44  of the housing, and a bottom lip  46  projects forwardly of front end  44 . An entrance section  48  of through passage  34  opens at a rear end  50  of the housing and through which cable  28  extends. The entrance section is enlarged relative to the dimensions of the cable so that the cable is freely positioned within the enlarged entrance section as best seen in FIG.  3 . An intermediate section is defined by a pair of side walls  52  which gradually slope outwardly or diverge from entrance section  48  to receptacle  42 . A plurality of guide rails  54  are located along the upper edges of side walls  40  of the base housing, with the guide rails opening inwardly toward axis  34 . 
     Other features of base housing  22  include an upstanding octagonal mounting post  56 , a rearwardly projecting strain relief tongue  58 , a pair of upwardly opening latch recesses  60  (FIG.  4 ), a pair of bottom opening mounting holes  62  (FIG. 2) and a pair of cylindrical mounting members  64 , all for purposes described hereinafter. Mounting members  64  are joined to one side wall  40  of the base housing by a pair of frangible webs  66 . 
     Cover  24  of connector  20  is a generally flat, elongated or rectangular member having guide ribs  68  along opposite edges thereof. The cover is a one-piece structure unitarily molded of plastic material. Guide ribs  68  slide beneath guide rails  54  of base housing  22  when the cover is slidably mounted to the housing in the direction of arrow “A” (FIG. 4) as described hereinafter. The cover has an upstanding octagonal mounting post  70  similar to upstanding mounting post  56  of the base housing. The cover has a forwardly projecting top lip  72  similar to bottom lip  46  of the base housing. The cover has a rearwardly projecting strain relief shroud  74  which cooperates with strain relief tongue  58  of the base housing to provide a strain relief means for cable  28 , as will be seen hereinafter. 
     Referring to FIG. 5, the bottom of cover  24  has a pair of integrally molded latch bosses  76  which latch within recesses  60  (FIG. 4) of the base housing. A stop  78  also projects from the bottom of the cover. Finally, the cover includes a transparent window  80  which affords visual inspection of the cable within the connector. The entire cover may be molded of substantially transparent plastic material which is texturized in areas  82  so that substantially the entire cover is opaque except for transparent window  80 . 
     Referring to FIG. 4, fanout insert  26  is molded of plastic material and includes a plurality of through holes  84  which receive fibers  30  of cable  28  and which spread the individual fibers apart from each other transversely of axis  36 . The number of through holes does not have to match the number of fibers of the cable. For instance, in the illustrated embodiment, there are sixteen through holes  84  and only fourteen fibers  30  of cable  28 . As stated above, the fibers extend through a plurality of tubes  32  projecting from a front end  86  of the fanout insert. The rear ends of the tubes preferably are fixed, as by epoxy, within the front ends of through holes  84 . The fiber ends project beyond the front ends of the tubes as seen in the drawings. The tubes provide both protection for the projecting fibers as well as means for readily manipulating the fibers. As seen in FIGS.  1 - 3 , the tubes, themselves, are protected by forwardly projecting top lip  72  of the cover and bottom lip  46  of the base housing. 
     FIG. 6 shows how a plurality of connectors  20  can be mounted on top of each other in a stacked array. When one connector is mounted on top of another connector, mounting post  56  which projects upwardly from base housing  22  and mounting post  70  which projects upwardly from cover  24  of a bottom connector are inserted into mounting holes  62  (FIG. 2) in the bottom of the base housing of a top connector. Therefore, the cover of the bottom connector cannot move relative to the base housing thereof. The mounting posts may be sized for positioning into the mounting holes by a press-fit. Although FIG. 6 shows two connectors in a stacked array, of course more than two connectors can be stacked as described. Furthermore, the mounting posts  56  and  70  may be press fit into mounting holes in a printed circuit board (not shown). 
     FIGS. 7-10 show how cylindrical mounting members  64  can be brokenaway from base housing  22  for using the connector in applications wherein the connector is not mounted to a supporting structure. In other words, cylindrical mounting members  64  have through holes  88  (FIGS. 7 and 8) for receiving therethrough appropriate fasteners, such as rivets, screws or bolts, for fastening the connector to an appropriate support structure. When an application dictates that the connector be used as a stand-alone unit, mounting members  64  are broken-away from base housing  22 . This is accomplished by using frangible webs  66  which join the mounting members to the base housing and which are much smaller than the mounting members. FIGS. 7 and 7A show that notches  90  are formed at the tops of the webs immediately adjacent the housing. FIGS. 8 and 8A show that notches  92  are formed at the bottoms of the webs immediately adjacent the housing. These notches weaken the junctures between the webs and the housing so that the webs readily break away from the housing leaving fairly clean breaking points as seen in FIGS. 9 and 10. 
     Referring to FIGS. 11 and 12 in conjunction with FIG. 4, fanout insert  26  includes a plurality of polarizing projections  94  on opposite sides thereof, and base housing  22  includes a plurality of polarizing projections  96  on the opposite sides of receptacle  42  defined by side walls  40 . These complementary interengaging polarizing projections  94  and  96  define a tongue and groove arrangement at the sides of fanout insert  26  and the sides of receptacle  42  to ensure that the fanout insert is positioned in the receptacle only in a given orientation so that the fibers of cable  28  are oriented according to an expected scheme in which they have been threaded through the insert and through tubes  32 . 
     At this point, it can be seen in FIGS. 4,  11  and  12  that a small tube or band  98  is positioned about cable  28  at a point where the outer cladding of the cable has been removed to expose individual fibers  30 . This band may be fabricated of heat shrinkable material and heat shrunk about the cable at this point. The band prevents the fibers from fraying the outer cladding of the cable after they have been exposed for spreading by fanout insert  26 . As seen in FIG. 3, the band is free to move within enlarged entrance section  48 . This allows the cable and fibers to move axially of the entire connector within the limits of the band captured in the enlarged entrance section thereby improving temperature cycling performance. Stop  78  on the underside of cover  24  defines the forward limit of such movement. 
     After fanout insert  26 , cable  28 , fibers  30  and tubes  32  have been prepared as shown in FIG. 4, and after this subassembly has been inserted and polarized within base housing  22  as shown in FIGS. 11 and 12, cover  24  is assembled to the base housing as shown in FIGS. 13 and 14. Specifically, the cover is slidably mounted to the base housing in the direction of arrows “A”. During mounting, guide ribs  68  at opposite edges of the flat cover slide beneath guide rails  54  along the top edges of side walls  40  of the base housing. The cover is slidably mounted to the housing until a pair of stops  100  at opposite sides of the cover abut against a pair of stops  102  at opposite sides of the base housing as seen in FIG.  1 . 
     Once cover  24  is fully slidably mounted onto base housing  22  with stops  100  and  102  in abutment, two functions occur as best seen in FIG.  15 . First, latch bosses  76  (FIG. 5) on the underside of cover  24  snap into latching interengagement with latch recesses  60  (FIG. 4) in the top of the base housing. Second, strain relief tongue  58  at the rear of the base housing enters strain relief shroud  74  at the rear of the cover. This sandwiches cable  28  between the tongue and the cover. As best seen in FIGS. 4 and 5, shroud  74  is flattened and is generally C-shaped to define a pair of bottom, inwardly directed flanges  74   a . Tongue  58  also is flat, whereby ribbon cable  28  is sandwiched between the flat tongue and the flat top of the shroud, with flanges  74   a  of the shroud interengaging with the bottom of the tongue. The shroud is joined to the cover by a thin web  74   b.  With the cover and the base housing being fabricated of plastic material, web  74   b  of shroud  74  and tongue  58  are flexible whereby the interengaged strain relief means provide strain relief for the cable. The size and location of latch bosses  76  and latch recesses  60  in relation to tongue  58  and shroud  74  preferably should be such that the tongue enters the shroud before the latch bosses of the cover engage the base housing which, otherwise, might move the tongue and shroud out of alignment. This can be seen in FIG. 15 where tongue  58  has entered shroud  54  before latch bosses  76  engage the housing for movement into the latch recesses. 
     Finally, FIG. 16 shows a connector  20 A which does not include mounting post  56  (FIG. 4) on base housing  22  nor mounting post  70  (FIG. 4) on cover  24 . This simply shows that the connector can be made for non-stackable applications. 
     It will be understood that the invention may be embodied in other specific forms without departing from the spirit or central characteristics thereof. The present examples and embodiments, therefore, are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein.