Abstract:
A system is provided for mounting a connecting device to a substrate with relative floating movement therebetween. The system includes a connector housing adapted for mounting on the substrate and including at least one elongated channel in a side of the housing. The channel extends generally perpendicular to the substrate and has an elongated restricted mouth opening at a side thereof. An elongated fastening post is snap-fit into the channel past the restricted mouth thereof to a preload position. A cross-dimension of the channel is larger than a cross-dimension of the fastening post so that the post can float relative to the housing. A fastener engages with the substrate and is operatively associated with the fastening post for tightening the post against the substrate, leaving the connector housing with floating movement relative to the substrate in a direction generally parallel to the substrate. The post may be longer than the channel to provide for floating movement of the housing relative to the substrate in a direction generally perpendicular to the substrate. In an alternative embodiment, at least a pair of connector housings are stacked on the substrate one on top of another. The elongated fastening post is long enough to snap-fit into the channels of both housings.

Description:
RELATED APPLICATION  
       [0001]    This is a continuation-in-part of co-pending application Ser. No. 09/568,517, filed May 9, 2000, and which is assigned to the Assignee of the present application. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    This invention generally relates to the art of connector assemblies and, particularly, to a system for mounting one or more connecting devices to a substrate with relative floating movement therebetween.  
         BACKGROUND OF THE INVENTION  
         [0003]    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 ceramic. A ferrule holder or other housing component of the connector embraces the ferrule and may be fabricated of such material as molded plastic. A spring may be disposed within the housing or ferrule holder such that the ferrule is yieldably biased forwardly for engaging another fiber-mounting ferrule of a mating connecting device.  
           [0004]    A pair of fiber optic connectors or a connector and another optical fiber transmission device often are mated in an adapter which centers the fibers to provide low insertion losses. The adapter couples the connectors together so that their encapsulated fibers connect end-to-end. The adapter may be an in-line component, or the adapter can be designed for mounting in an opening in a panel, backplane, circuit board or the like.  
           [0005]    Various problems continue to be encountered in designing fiber optic connector assemblies or other connector assemblies, including applications involving backplanes, motherboards, daughterboards and the like. Such problems include properly and precisely placing a connector assembly on a substrate, such as a printed circuit board, accommodating misalignment of the connectors during mating, allowing relative floating movement between various components of the system and similar positional-type problems. Other problems simply involve efforts to simplify the design of connector assemblies. The present invention is directed to solving these problems and to providing various improvements in such connector assemblies, particularly in accommodating misalignment of the connectors during mating by providing relative floating movement of at least one of the connectors. Although the invention is shown herein embodied in a fiber optic connector assembly, the invention is equally applicable for use with other types of connector assemblies, such as electrical connector assemblies.  
         SUMMARY OF THE INVENTION  
         [0006]    An object, therefore, of the invention is to provide a new and improved system for mounting a connecting device to a substrate with relative floating movement therebetween.  
           [0007]    Another object of the invention is to provide a new and improved system for mounting a pair of connecting devices on a substrate one on top of another.  
           [0008]    In one exemplary embodiment of the invention, the system includes a connector housing adapted for mounting on the substrate and including at least one elongated channel in the side of the housing. The channel extends generally perpendicular to the substrate and has an elongated restricted mouth opening at a side thereof. An elongated fastening post is snap-fit into the channel past the restricted mouth to a preload position. A fastener is engaged with the substrate and is operatively associated with the fastening post for tightening the post against the substrate.  
           [0009]    As disclosed herein, a cross-dimension of the channel is larger than a cross-dimension of the fastening post so that the post can float relative to the housing. Therefore, when the post is tightened against the substrate, the connector housing is left with floating movement relative to the substrate in a direction generally parallel to the substrate. It also is contemplated that the fastening post be longer than the channel to provide for floating movement of the housing relative to the substrate in a direction generally perpendicular to the substrate.  
           [0010]    The connector housing is adapted for mating with a complementary connecting device along an axis generally parallel to the substrate and perpendicular to the post-receiving channel. The larger cross-dimension of the channel is generally perpendicular to the mating axis whereby the housing floats in that direction. The cross-dimensions of the channel and the fastening posts are substantially equal in a direction generally parallel to the mating axis, whereby the housing is prevented from floating in that direction.  
           [0011]    Other features of the invention include the fastening post having an internally threaded end near the substrate, and the fastener comprises an externally threaded bolt. The fastening post has enlarged heads at opposite ends thereof engageable with stop surfaces on the connector housing at opposite ends of the channel. The fastening bolt has a socket in an end thereof remote from the substrate for holding the post to facilitate tightening the post against the substrate.  
           [0012]    In another embodiment of the invention, at least a pair of the connecting devices are stacked on the substrate one on top of another. Each connecting device includes the same connector housing. The elongated fastening post is long enough to snap into the channels in both housings. The post includes means for spacing the housings of the devices from each other.  
           [0013]    In a third embodiment of the invention, a pair of the connecting devices again are stacked on the substrate one on top of another. The elongated fastening post comprises a first fastening post and is snap-fit into the channel in the connector housing of the bottom-most connecting device adjacent the substrate. A bridging bracket is secured to the substrate and extends over the bottom-most connecting device. A second elongated fastening post is secured to the bridging bracket and is snap-fit into a channel in the connector housing of a top-most connecting device above the bridging bracket. 
       
    
    
       [0014]    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  
       [0015]    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:  
         [0016]    [0016]FIG. 1 is a perspective view of a first embodiment of a mating connector assembly incorporating the concepts of the invention, with the assembly in unmated condition;  
         [0017]    [0017]FIG. 2 is a side elevational view of the mating connector assembly as shown in FIG. 1;  
         [0018]    [0018]FIG. 3 is a perspective view of the mating connector assembly of FIG. 1, in mated condition;  
         [0019]    [0019]FIG. 4 is an exploded perspective view of the daughterboard connector assembly as seen to the right in FIGS. 1 and 2;  
         [0020]    FIGS.  5 A- 5 C are a side elevational view, top plan view and axial sectional view, respectively, of one of the elongated fastening posts;  
         [0021]    [0021]FIG. 6 is a top plan view of the daughterboard connector assembly, partially broken away to show the amount of floating between the connector assembly and the substrate generally parallel to the substrate;  
         [0022]    [0022]FIG. 7 is a side elevational view of the daughterboard connector assembly, partially broken away and in section to show the amount of floating movement between the connector assembly and the substrate in a direction generally perpendicular to the substrate;  
         [0023]    [0023]FIG. 8 is a view similar to that of FIG. 1, but of a second embodiment of the invention;  
         [0024]    [0024]FIG. 9 is a view similar to that of FIG. 2, but of the second embodiment;  
         [0025]    [0025]FIG. 10 is a view similar to that of FIG. 3, but of the second embodiment;  
         [0026]    [0026]FIG. 11 is a view similar to that of FIG. 4, but of the second embodiment;  
         [0027]    FIGS.  12 A- 12 C are views similar to FIGS.  5 A- 5 C, respectively, but of the second embodiment;  
         [0028]    [0028]FIG. 13 is a view similar to that of FIG. 7, but of the second embodiment;  
         [0029]    [0029]FIG. 14 is a view similar to that of FIGS. 1 and 8, but of a third embodiment of the invention;  
         [0030]    [0030]FIG. 15 is a view similar to that of FIGS. 4 and 11, but of the third embodiment of the invention.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0031]    Referring to the drawings in greater detail, FIGS.  1 - 7  show a first embodiment of the invention; FIGS.  8 - 13  show a second embodiment of the invention; and FIGS. 14 and 15 show a third embodiment of the invention. Referring first to FIGS.  1 - 3 , the invention is incorporated in a first embodiment of a mating connector assembly, generally designated  24 , which includes a backplane connector assembly, generally designated  26 , mateable with a daughterboard connector assembly, generally designated  28 . The backplane connector assembly is mounted in an aperture  30  in a substrate, panel or backplane  32  which, in the preferred embodiment, is a printed circuit board. Specifically, backplane  32  can be considered the “motherboard” herein. The daughterboard connector assembly is mounted on a top surface of a second printed circuit board  34  which is considered the “daughterboard” herein.  
         [0032]    Backplane connector assembly  26  includes an adapter, generally designated  36 , which is mounted in aperture  30  in motherboard  32 . Four fiber optic connector modules, generally designated  38 , are inserted into adapter  36 , through aperture  30 , from the front of backplane  32 . Each fiber optic connector module is terminated to a multi-fiber cable  40 . Each cable is a flat or “ribbon” cable having a plurality of optical fibers.  
         [0033]    After daughterboard connector assembly  28  is mounted on daughterboard  34 , four fiber optic connector modules, generally designated  42 , are inserted into the back of the connector housing, as described hereinafter. Each module  42  is terminated to a flat, multi-fiber cable  44  similar to fiber optic cables  40 . Backplane connector assembly  26  and daughterboard connector assembly  28  are mateable in the direction of arrows “A” (FIGS. 1 and 2) to a mated condition shown in FIG. 3, wherein the fibers of cables  40  and  44  are functionally connected.  
         [0034]    Adapter  36  of the backplane connector assembly is fixed to backplane  32  by a pair of fasteners  46 . The adapter includes a housing  48  and a pair of flexible latch arms  50  spaced outwardly from opposite sides of the housing. The housing also has a pair of outwardly projecting alignment ribs  52  on opposite sides thereof.  
         [0035]    At this point, reference is made to FIG. 1 where three intersecting arrows “X”, “Y” and “Z” are shown. Arrow “X” represents a direction generally parallel to daughterboard  34 . Arrow “Y” represents a direction generally perpendicular to the daughterboard. Arrow “Z” represents a direction generally parallel to the daughterboard but corresponding to the mating direction of the connector assemblies as described above by arrows “A”. In other words, direction “X” is transversely of the mating direction of the connector assemblies.  
         [0036]    [0036]FIG. 4 shows daughterboard connector assembly  28  to include a connector housing, generally designated  54 , adapted for mounting on top of daughterboard  34 . The housing is molded of dielectric material such as plastic or the like and includes four through passages or receptacles  56  for receiving fiber optic connector modules  42  in the direction of arrow “B”. The housing has a pair of forwardly projecting alignment flanges  58  at opposite sides thereof and between which housing  48  (FIG. 1) of adapter  36  is inserted. Alignment ribs  52  on opposite sides of the adapter housing ride into grooves  60  on the insides of alignment flanges  88 . A pair of latch ribs  62  also are provided on opposite sides of housing  54  for engagement by latch arms  50  of adapter  36 . A bottom flange  64  projects forwardly of housing  54  flush with a bottom surface  66  of the housing. The flange has a bottom hook portion  64   a  and a top chamfered portion  64   b . The bottom hook portion overlaps an edge  68  of daughterboard  34 . The top chamfered portion is engageable by the front bottom edge of adapter housing  48  to prevent the bottom edge of the adapter housing from “stubbing” the front edge of the daughterboard during mating of the connector assemblies.  
         [0037]    The invention contemplates that connector housing  54  of daughterboard connector assembly  28  includes elongated channels, generally designated  70 , on opposite sides thereof for receiving a pair of elongated fastening posts, generally designated  72 . As will be described in greater detail hereinafter, the fastening posts are snap-fit into the channels to preload positions so that they can be transported and manipulated as a subassembly with housing  54 . A pair of fasteners in the form of externally threaded bolts  74  are inserted from the bottom of daughterboard  34  in the direction of arrows “C”, through holes  76  in the daughterboard, and into the bottoms of fastening posts  72 , as will be seen in greater detail hereinafter. The bolts tighten fastening posts  72  to daughterboard  34 , leaving connector housing  54  (i.e., daughterboard connector assembly  28 ) with floating movement relative to the daughterboard, all of which will be seen hereinafter.  
         [0038]    FIGS.  5 A- 5 C show that each fastening post  72  is elongated, generally cylindrical and includes a pair of enlarged heads  78  at opposite ends thereof. The bottom of each fastening post is internally threaded, as at  80 , for receiving a respective one of the bolts  74  to tighten the fastening post onto the top of daughterboard  34 . The top of each fastening post includes a hexagonal socket  82  for receiving a wrench to prevent rotation of the fastening post while the bolt is threaded thereinto or to disassemble the assembly from the daughterboard if necessary.  
         [0039]    Generally, FIG. 6 shows how fastening posts  72  within channels  70  provide for floating movement of connector housing  54  and, therefore, daughterboard connector assembly  28 , relative to daughterboard  34  in the “X” direction described above, i.e., generally parallel to daughterboard  34  and generally perpendicular to the mating direction “Z” of the connector assemblies. First of all, FIG. 6 shows that each channel  70  has a restricted mouth  84  which is slightly narrower than the diameter of the respective fastening post  72  between heads  78  thereof. Therefore, the fastening posts can be snap-fit into the channels, past the restricted mouths  84  of the channels, to a preload position to facilitate handling and manipulation of the connector assembly without the fastening posts falling away therefrom.  
         [0040]    [0040]FIG. 6 shows that each fastening post  72  has a cross-dimension substantially equal to the cross-dimension of the interior of channel  70  in the “Z” direction. This prevents any floating movement of the housing relative to the daughterboard in the “Z” or mating direction of the connector assemblies. On the other hand, the cross-dimension of the interior of each channel  70 , i.e., between restricted mouth  84  and a base or bottom  86  of the channel, is larger than the cross-dimension of the fastening post. This differential in the dimensions is shown by arrows “D”. This differential allows for floating movement of housing  54  and daughterboard connector assembly  28  relative to daughterboard  34  in the direction of arrow “X”, i.e., generally parallel to the daughterboard and generally perpendicular to the mating direction of the connector assemblies.  
         [0041]    Generally, FIG. 7 shows the amount of floating action between connector housing  54  and daughterboard connector assembly  18  relative to daughterboard  34  in a direction generally perpendicular to the daughterboard. More particularly, it can be seen that each fastening post  72  is longer than its respective channel  70 . Each channel has top and bottom ends  88  and  90 , respectively. Each fastening post  72  has enlarged heads  78  as described above. These heads abut opposite ends of the respective channel. However, it can be seen in FIG. 7 that bottom end  90  of the channel is recessed, as at  92 , to accommodate the bottom head  78  of the fastening post so that the connector housing can move flush downwardly onto the top of the daughterboard rather than constantly engaging the relatively small head of the fastening bolt. In any event, the length of the fastening bolt, between enlarged heads  78 , is longer than the effective length of the post-receiving channel so that floating movement of connector housing  54  and daughterboard connector assembly  28  relative to daughterboard  34  is provided as indicated by arrows “E”. This floating movement is in the “Y” direction described above, i.e., generally perpendicular to daughterboard  34  and generally perpendicular to the mating direction of the connector assemblies as indicated by both arrows “A” and “Z”.  
         [0042]    FIGS.  8 - 13  show a second embodiment of the invention wherein a mating connector assembly, generally designated  24 A, includes a backplane connector assembly, generally designated  26 A, mateable with a daughterboard connector assembly, generally designated  28 A. Backplane connector assembly  26 A includes a pair of adapters  36  one on top of another and mounted in a pair of apertures  30  motherboard  32 . Daughterboard connector assembly  28 A includes a pair of connector housings  54  stacked one on top of the other on top of daughterboard  34 . Otherwise, connector assemblies  26 A and  28 A are the same as connector assemblies  26  and  28  described above in relation to FIGS.  1 - 7 . Consequently, like reference numerals have been applied in FIGS.  8 - 13  to refer to like components described above in relation to the first embodiment of FIGS.  1 - 7 . The descriptions and functions of those components will not be repeated in order to avoid unnecessarily expanding the specification.  
         [0043]    The major difference between the second embodiment of FIGS.  8 - 13  and the first embodiment of FIGS.  1 - 7  is that a single elongated fastening post, generally designated  72 A, is snap-fit in each pair of vertically aligned channels  70  of the pair of connecting housings  54  of daughterboard connector assembly  28 A. The pair of elongated fastening posts  72 A perform the dual function of mounting the connector housings on daughterboard  34  as well as stacking the housings one on top of another, and in a spaced relationship.  
         [0044]    Elongated fastening posts  72 A of the second embodiment are best shown in FIGS.  11 - 13 . Like fastening posts  72  of the first embodiment, each fastening post  72 A of the second embodiment is elongated, generally cylindrical and includes a pair of enlarged heads  78  at opposite ends thereof. The bottom of each fastening post is internally threaded, as at  80 , for receiving a respective one of the bolts  74  to tighten the fastening posts onto the top of daughterboard  34 . The top of each fastening post includes the hexagonal socket  82  for receiving a wrench to prevent rotation of the fastening post while the bolt is threaded thereinto or to disassemble the assembly from the daughterboard if necessary. Other than the fact that fastening posts  72 A are longer than fastening posts  72  to accommodate the pair of stacked connector housings, each fastening post  72 A of the second embodiment includes a ring-like peripheral flange  96  projecting outwardly of the post generally equidistant between opposite ends of the post. As best seen in FIG. 13, flange  96  functions as a spacer to vertically space the pair of connector housings  54  from each other above daughterboard  34 .  
         [0045]    Like the first embodiment, fastening posts  72 A of the second embodiment are dimensioned relative to channels  77  to provide for floating movement in the “X”, “Y” and “Z” directions. In addition, both connector housings  54 , with or without modules  42 , can be assembled to a pair of fastening posts  72 A to comprise a subassembly for manipulation and handling.  
         [0046]    [0046]FIGS. 14 and 15 show a third embodiment of the invention which, like the second embodiment of FIGS.  8 - 13 , a daughterboard connector assembly  28 B is structured for stacking a pair of connector housings  54  one on top of another on top of daughterboard  34 . Again, like reference numerals have been applied in FIGS. 14 and 15 to refer to like components described above in relation to the first and second embodiments of FIGS. 113. In addition, the respective descriptions of the structure and function of the components will not be repeated.  
         [0047]    In the third embodiment of FIGS. 14 and 15, a pair of the elongated fastening posts  72  of the first embodiment are snap-fit into channels  70  of each connector housing  54  to provide a pair of subsassemblies for handling and manipulation and to provide for floating movement of the connector housings relative to daughterboard  34  in the “X”, “Y” and “Z” directions. The bottom-most connector housing is connected to the daughterboard the same as described above in relation to the first embodiment of FIGS.  1 - 7 .  
         [0048]    However, FIG. 15 best shows the configuration of a bridging bracket, generally designated  98 , which mounts the top-most connector housing spaced above the bottom housing. The bridging bracket is configured in an inverted, generally U-shape, including a pair of depending leg portions  98   a  joined by a bridge portion  98   b . A flange  98   c  projects outwardly from the bottom of each leg portion and includes a pair of holes  100  for receiving a pair of bolt-like fasteners  102  projecting upwardly from daughterboard  34 . Holes  100  may be internally threaded for receiving externally threaded fasteners  102 . A pair of externally threaded fasteners  74  extend upwardly through bridge portion  98   b  of bracket  98  for threading into fastening posts  72  of the top-most connector housing  54 .  
         [0049]    In assembling daughterboard connector assembly  28 B, the bottom-most connector housing  54  is assembled to daughterboard  34  as shown in FIG. 15 the same as with the first embodiment of FIGS.  1 - 7 . Bridging bracket  98  then is assembled to the daughterboard by using fasteners  102 . The top connector housing  54  then is mounted on top of the bridging bracket. In an alternative assembly procedure, bridging bracket  98  could be assembled to the top connector housing by using fasteners  74  through bridge portion  98   b  of the bracket before mounting to daughterboard  34 . The bracket and the top connector housing, thereby, can comprise an additional subassembly to facilitate handling and manipulation and to more easily thread fasteners  74  from within the bridging bracket.  
         [0050]    In either the second embodiment of FIGS.  8 - 13  or the third embodiment of FIGS. 14 and 15, it can be seen that high density interconnections can be made on daughterboard  34  without using up additional space or “real estate” on the daughterboard or substrate. With the second embodiment of FIGS.  8 - 13 , two or more connector housings can be stacked on top of each other, using the same amount of space on daughterboard  34  as a single connector housing. The connectors are spaced from each other and can work independently to increase the connection density without increasing the space on the subjacent substrate or daughterboard.  
         [0051]    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.