Abstract:
A system is disclosed for mounting a connecting device to a substrate with relative floating movement therebetween. The system includes a connector housing. A fastening nut is captured by the housing with relative floating movement therebetween. The nut includes a shank portion extending toward the substrate through an opening in a wall portion of the housing. The shank portion of the nut is longer than the thickness of the wall portion of the housing. A fastener is engaged with the substrate and is operatively associated with the fastening nut for tightening the nut against the substrate, leaving the connector housing with floating movement relative to the substrate.

Description:
FIELD OF THE INVENTION 
     This invention generally relates to the art of connector assemblies and, particularly, to a system for mounting a connecting device to a substrate with relative floating movement therebetween. 
     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 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. 
     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. 
     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. 
     SUMMARY OF THE INVENTION 
     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. 
     In the exemplary embodiment of the invention, the system includes a connector housing and a fastening nut captured by the housing with relative floating movement therebetween, The nut includes a shank portion extending toward the substrate through an opening in a wall portion of the housing. The shank portion of the nut is longer than the thickness of the wall portion of the housing. A fastener is engaged with the substrate and is operatively associated with the fastening nut for tightening the shank portion of the nut against the substrate, leaving the connector housing with floating movement relative to the substrate. 
     In the exemplary embodiment of the invention, the fastening nut includes an enlarged head portion captured within a cavity in the housing behind the wall portion. A passage extends through the wall portion and through which the shank portion of the fastening nut extends. The passage communicates with the cavity. The passage is wider than the shank portion of the fastening nut. A restricted mouth communicates with at least one of the passage and cavity through which the fastening nut is snap-fit to mount the nut to the housing. 
     The fastener may comprise a rivet extending through the fastening nut. Other fasteners, such as screws, are contemplated by the invention. 
     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 in which: 
     FIG. 1 a perspective view of a mating connector assembly embodying the concepts of the invention, with the assembly in unmated condition; 
     FIG. 2 is a side elevational view of the mating connector assembly as shown in FIG. 1; 
     FIG. 3 perspective view of the mating connector assembly of FIG. 1, in mated condition; 
     FIG. 4 is an exploded perspective view of the backplane connector assembly as seen to the left in FIGS. 1 and 2; 
     FIG. 5 is a perspective view of one of the shutter assemblies for the adapter in the backplane connector assembly of FIG. 4; 
     FIG. 6 is a perspective view of the other shutter assembly for the adapter; 
     FIG. 7 is an enlarged perspective view, broken away to show the floating mount between the adapter and the backplane in the backplane connector assembly of FIG. 4; 
     FIG. 8 is a perspective view of one of the fiber optic connector modules of the backplane connector assembly of FIG. 4; 
     FIG. 9 is a perspective view of the housing of the connector module of FIG. 8; FIG. 10 is perspective view showing the assembly procedure of the module of FIG. 8; 
     FIG. 11 is an exploded perspective view of the daughterboard connector assembly as seen to the right of FIGS. 1 and 2; 
     FIG. 12 is an exploded bottom perspective view of the two-part housing of the daughterboard connector assembly; 
     FIG. 13 is a perspective view of the front housing part of the daughterboard connector assembly; 
     FIG. 14 is a perspective view of one of the fiber optic connector modules of the daughterboard connector assembly of FIG. 11; 
     FIG. 15 is an exploded perspective view of the module of FIG. 14; 
     FIG. 16 is a perspective view of the pin keeper of the module of FIG. 14; 
     FIG. 17 is a perspective view of the spring pusher member of the module of FIG. 14; 
     FIG. 18 is a perspective view showing the assembly of the coil spring to the pin keeper of FIG. 16; 
     FIG. 19 is a perspective view showing the assembly of the spring to the pusher member of FIG. 17; and 
     FIGS. 20-22 are sequential top plan views, partially broken away, showing the mating of the mating connector assembly of FIGS. 1-3. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the drawings in greater detail, and first to FIGS. 1-3, the invention is embodied in 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 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. 
     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. 
     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. 
     Referring to FIG. 4, adapter  36  includes a housing  46  which may be fabricated of molded plastic material. The housing defines a front mating end  46   a  and a rear terminating end  46   b.  The front mating end is open, as at  46   c,  and through which the ferrules (described hereinafter) of fiber optic connector modules  38  can project. Terminating end  46   b  is open, as at  46   d,  for receiving connector modules  38  in the direction of arrows “B”. Housing  46  of adapter  36  has an outwardly projecting alignment rib  48  on each opposite side thereof and extending in the mating direction of the connector assembly, for purposes described hereinafter. 
     FIG. 5 shows a shutter assembly, generally designated  50 , for closing opening  46   b  of adapter  46 , and FIG. 6 shows a shutter assembly, generally designated  52 , for closing mating opening  46   c  of the adapter. Shutter assembly  50  includes a pair of spring-loaded shutters  50   a  which close opening  46   d  on opposite sides of an interior partition  54  (FIG.  4 ). The shutter members are pivotally mounted on a plate  50   b  which includes a plurality of pegs  50   c  which are press-fit into holes  56  in adapter housing  46 . Similarly, shutter  52   a  of shutter assembly  52  is spring-loaded and is mounted on a plate  52   b  which has a plurality of pegs  52   c  which are press-fit into a plurality of holes  58  in adapter housing  46 . Shutters  50   a  and  52   a  provide dust covers for the interior of adapter  36 . 
     Referring to FIG. 7 in conjunction with FIG. 4, means are provided for mounting adapter  36  to backplane  32  in order to provide relative floating movement therebetween. Specifically, a pair of T-nuts, generally designated  60 , are floatingly mounted to adapter  36  and receive a pair of rivets  62  insertable in the direction of arrows “C” through a pair of mounting holes  64  in the backplane. The rivets have enlarged head portions  62   a  which will engage the surface of the backplane. Mounting holes  64  are spaced on opposite sides of opening  30 . 
     Still further, each T-nut  60  includes a shank portion  60   a  and an enlarged head  60   b.  A mounting flange, generally designed  66 , is molded integrally with each opposite side of adapter housing  46 . Each flange  66  includes an interior cavity  66   a  which receives head portion  60   b  of one of the T-nuts  60 . A passage  66   b  extends through flange  66  toward backplane  32  in communication with cavity  66   a  for receiving shank portion  60   a  of the T-nut. The following parameters should be understood: (1) the dimensions of head portion  60   b  are smaller than cavity  66   a  so that the head portion can float within the cavity, (b) the cross dimensions of shank portion  60   a  are less than the dimensions of passage  66   b  so that the shank portion can float within the passage and (c) the length of shank portion  60   a  is greater than the thickness of a wall portion  67  of flange  66  below the head portion (i.e., the thickness indicated by double-headed arrow “D” (FIG.  7 ). Therefore, when rivet  62  tightens the T-nut onto surface  32   a  of backplane  32 , the adapter does not become tightened to the backplane and is allowed to float relative thereto. Lastly, passage  66   b  has a restricted mouth, as at  66   e,  so that the T-nut can be snap-fit into flange  66  to mount the nut to adapter housing  46 . It should be understood that rivet  62  equally could be a threaded fastener, such as a screw, for threadingly engaging the T-nut. 
     FIGS. 8-10 show one of the fiber optic connector modules  38  which are inserted into adapter  36  as described above. Specifically, each module  38  includes a ferrule  68  terminated to one of the multi-fiber cables  40  with ends  40   a  (FIG. 8) of the fibers exposed at a mating face  68   a  of the ferrule. The ferrule includes a pair of alignment holes  68   b  opening into mating face  68   a.  The ferrule is captured by a manually manipulatable housing, generally designated  70 , which includes a front portion  70   a  which actually captures the ferrule, and a rear portion defined by a pair of laterally spaced arms  70   b  that are graspable between an operator&#39;s fingers. FIG. 10 shows that ferrule  68  has a peripheral flange  68   c.  The front portion  70   a  of housing  70  includes a pair of forward latch hooks  70   c  on two opposite sides of the housing and a pair of flexible latch arms  70   d  on the other two opposite sides of the housing. As seen best in FIG. 9, each latch arm  70   d  includes an inside chamfered latch hook  70   e.  Latch hooks  70   c  engage the front of flange  68   c  of the ferrule, and latch hooks  70   e  on latch arms  70   d  engage the rear edges of flange  68   c  to hold the ferrule encapsulated within front portion  70   a  of housing  70 . 
     Still referring to FIGS. 8-10, manually graspable arms  70  include serrations  71  on the outsides thereof to facilitate manual grasping thereof. A latch block  70   f  projects outwardly from each arm for latching engagement within adapter  36 . Each arm  70   b  also includes an interior channel  70 g for guiding ferrule  68  into front portion  70   a  of the housing. 
     FIG. 10 shows that ferrule  68  is insertable into housing  70  of connector module  38  in the direction of arrow “E”. The ferrule moves within channels  70   g  of arms  70   b  and through an open rear end  70   h  of front portion  70   a  of the housing. The ferrule becomes latched in a position projecting out of an open front end  70   i  (FIG. 9) of the housing and is locked in the position shown in FIG. 8, with the ferrule projecting forwardly of the manually manipulatable housing. 
     FIGS. 11-13 show daughterboard connector assembly  28  to include a twopart housing defined by a front housing part, generally designated  72 , and a rear housing part, generally designated  74 . The rear housing part is insertable into the front housing part in the direction of arrow “F” (FIG.  11 ). Rear housing part  74  has a flexible latch arm  74   a  with a latch hook  74   b  which latches behind a front latch shoulder  72   a  (FIG. 13) when the two housing parts are initially assembled. FIG. 13 also shows a second latch shoulder  72   b  which is located rearwardly of latch shoulder  72   a,  for purposes described hereinafter. Each housing part  72  and  74  may be a one-piece structure unitarily molded of dielectric material such as plastic or the like. 
     Generally, a system is provided for mounting front housing part  72  of daughterboard connector assembly  28  on daughterboard  34  with considerable precision. Specifically, the daughterboard has a pre-placement hole  76  spaced between a pair of positioning holes  78  of as seen in FIG. 11. A pair of rivets  80  are insertable through positioning holes  78 . As best seen in FIG. 12, a pre-positioning peg  82  projects downwardly from a bottom surface  72   d  of front housing part  72  for insertion into preplacement hole  76  with substantially zero insertion forces. In other words, hole  76  is larger than peg  82 . A pair of positioning pegs  84  project downwardly from surface  70   d  for insertion into positioning holes  78  in daughterboard  34  by a press-fit to precisely fix the housing on the substrate. Peg  82  is solid, but pegs  84  are hollow for receiving rivets  80  therethrough to solidly lock the front housing part to the daughterboard. Pre-placement peg  82  is longer than positioning pegs  84  so that it is easy for an operator to locate and insert pre-placement peg  82  into pre-placement hole  76 . The housing then can be easily pivoted about peg  82  until positioning pegs  84  are aligned with positioning holes  78 . 
     Still referring to FIG. 12, positioning pegs  84  are provided with crushable ribs  84   a  on the exterior thereof and which are crushed or deformed when pegs  84  are press-fit into holes  78 . Bottom surface  72 d of front housing part  72  is recessed, as at  86 , around each positioning peg  84 . This recessed area is provided for receiving any plastic material, such as crushable ribs  84   a,  which might be shaved off of positioning pegs  84  when they are press-fit into positioning holes  78 . This ensures that bottom surface  72   d  of front housing part  72  is mounted flush on the flat top surface of daughterboard  34 . 
     Generally, an alignment system is provided between daughterboard connector assembly  28  and adapter  36  of backplane connector assembly  26 . More particularly, as best seen in FIGS. 11 and 12, front housing part  72  includes a pair of alignment flanges  88  at opposite sides of an open mating end  72   e  of the front housing part. Each flange has an outwardly chamfered or flared distal end  88   a  which is engageable by the front edges  90  (FIG. 1) of adapter  36  upon mating of the two connector assemblies. In essence, flared distal ends  88   a  allow for a degree of misalignment between the connector assemblies in an “X” direction generally perpendicular to mating direction “A” (FIG. 1) of the connectors, the “X” direction being generally parallel to daughterboard  34 . Alignment flanges  88  have grooves or slots  88   b  on the insides thereof for receiving alignment ribs  48  (FIG. 1) on opposite sides of adapter housing  46 . Slots  88 b have flared mouths  88   c  which are engageable by the distal ends of alignment ribs  48  to allow for a degree of misalignment between the two connector assemblies in a “Y” direction generally perpendicular to mating direction “A” as well as generally perpendicular to the aforesaid “X” direction and daughterboard  44 . Therefore, alignment flanges  88 , with the outwardly flared distal ends  88   a  thereof in combination with flared mouths  88   c  of slots  88   b,  are unique in utilizing a singular structure to allow for misalignment in two different “X” and “Y” directions. 
     Referring back to FIG. 2 in conjunction with FIGS. 11 and 12, a bottom flange  92  projects forwardly of front housing part  72  flush with bottom surface  72   d  (FIG. 12) of the front housing part. The flange has a bottom hook portion  92   a  and a top chamfered portion  92   b.  The bottom hook portion overlaps an edge  94  of daughterboard  34 . The top chamfered portion  92   b  is engageable by the front bottom edge of adapter housing  46  to prevent the bottom edge of the housing from “stubbing” the front edge of the daughterboard during mating of the connector assemblies. 
     FIGS. 14-19 show in greater detail one of the fiber optic connector modules  42  inserted into rear housing part  74  of daughterboard connector assembly  28 . Specifically, each module  42  includes a ferrule  96  for terminating multi-fiber cable  44 , with a resilient boot  98  providing strain-relief for the cable. The ferrule includes a pair of through holes or passages  96   a  (FIG. 15) for receiving a pair of alignment pins  100  fixed to a pin keeper  102  which abuts against the rear of ferrule  96  so that the distal ends of alignment pins  100  project forwardly of a front mating face  96   b  of ferrule  96 . A coil spring  104  is fixed to a rear end of pin keeper  102  as described hereinafter, and a spring pusher member  106  is fixed to the rear end of the coil spring. Both pin keeper  102  and pusher member  106  may be fabricated of molded plastic material. An integral, flexible latch arm  107  projects outwardly from the pusher member for latching the fiber optic connector module within rear housing part  74  of daughterboard connector assembly  28 . FIG. 16 shows that pin keeper  102  has a receptacle  102   a  at a rear end thereof for receiving a front end of coil spring  104 , along with a locking flange  102   b  for locking with a coil at the front end of the spring. Although not visible in FIG. 16, one of the locking flanges  102   b  are disposed at each opposite side of receptacle  102   a  of pin keeper  102 . 
     Similarly, FIG. 17 shows pusher member  106  to have a front receptacle  106   a  at a front end thereof for receiving a rear end of coil spring  104 . A locking flange  106   b  is disposed at each opposite side of receptacle  106   a  for locking with a coil at the rear end of the coil spring. 
     FIGS. 18 and 19 show the procedure for assembling coil spring  104  between pin keeper  102  and pusher member  106  and locking the coil spring to those components. It should be noted that coil spring  104  is oval in cross-configuration. A tool  110  has a generally oval shaft  112  for insertion in the direction of arrow “G” into oval coil spring  104 . The tool then is rotated in the direction of arrow “H” to effectively rotate the coil spring and cause the front open end coil  104   a  to lock behind flanges  102 b (FIG. 16) of pin keeper  102 . This subassembly then is positioned as shown in FIG. 19 so that the opposite open end coil  104   b  (FIG. 18) is aligned with locking flanges  106   b  of pusher member  106 . Shaft  112  of tool  110  then is inserted in the direction of arrow “I” (FIG. 19) into a rectangular hole  114  in pin keeper  102  and into coil spring  104 , and the tool rotated in the direction of arrow “J”. This effectively locks the coil spring in position between the pin keeper and the pusher member. Alignment pins  100  then are fixed within slots  116  (FIG. 19) so that they extend from the pin keeper as seen in FIG.  15 . Boot  98  then is inserted into opening  114  of the pin keeper; ferrule  96  is positioned onto alignment pins  100 ; fiber optic cable  44  is inserted into and through the entire assembly in the direction of arrow “K” (FIG.  15 ); and the alignment pins and cable are epoxied within the ferrule so that an entire self-contained unit is formed as shown in FIG.  14 . 
     Finally, FIGS. 20-22 show the mating procedure of backplane connector assembly  26  and daughterboard connector assembly  28  in the direction of arrows “A”, after the backplane assembly is mounted to backplane or motherboard  32  and after the daughterboard connector assembly is mounted to daughterboard  34 . These depictions also show that fiber optic cables  40  are engaged with yet another substrate or board  120 . Before proceeding, FIG. 20 best shows that adapter  36  of backplane connector assembly  26  has a pair of actuator arms  122  spaced outwardly from opposite sides thereof. The distal ends of actuator arms  122  are formed with a latch hook  122   a  and a forwardly facing chamfer  122   b.    
     Backplane connector assembly  26  and daughterboard connector assembly  28  are mateable in a two-step process represented by FIGS. 21 and 22. In the first step, hooks  122   a  of actuator arms  122  snap behind a pair of preliminary latch shoulders  124  (FIGS. 1 and 20) of rear housing part  74  of daughterboard connector assembly  28 . Latch hooks  74   b  on the ends of latch arms  74   a  at opposite sides of the rear housing part already have latched behind latch shoulders  72   a  (FIG. 14) of front housing part  72 . This prevents any rearward movement of any part of daughterboard connector assembly  28  in response to the preliminary latching of backplane connector assembly  26  thereto. Further movement of the connectors in the mating direction causes chamfers  122   b  at the distal ends of actuator arms  122  of adapter  36  to engage the chamfered distal ends of latch arms  74   a  of rear housing part  74  and move the latch arms out of engagement with latch shoulders  72   a.  Latch hooks  74   b  of latch arms  74   a  now are free to move between latch shoulders  72   a  and latch shoulders  72   b  of the front housing part to provide a degree of floating movement between the two housing parts in the “Z” or mating direction. In other words, there is no floating movement between the housing parts in the “Z” direction until full mating occurs with the backplane connector assembly. 
     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.