Mounting system for a connector assembly to a substrate

[0002] This invention generally relates to the art of connector assemblies, such as electrical connectors, fiber optic connectors and the like, and particularly to a system for mounting a connector assembly to a substrate, such as a printed circuit board.

[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.

[0006] An object, therefore, of the invention is to provide a new and improved system for mounting a connector assembly to a substrate, such as a panel, a printed circuit board or the like.

[0007] In the exemplary embodiment of the invention, the system includes a substrate having at least one pre-placement hole and at least one positioning hole. A connector housing includes a pre-placement peg for insertion into the pre-placement hole in the substrate with substantially zero insertion forces to generally place the housing on the substrate. The housing also includes a positioning peg for insertion into the positioning hole in the substrate by a press-fit to precisely fix the housing on the substrate.

[0008] The invention contemplates the provision of a recessed area about at least a portion of the positioning peg for receiving any material shaved off of the positioning peg as it is press-fit into the positioning hole.

[0009] As disclosed herein, the housing is fabricated of molded plastic material, with the positioning peg being molded integrally therewith. The positioning peg includes at least one crushable rib on the exterior thereof. The pre-placement peg is longer than the positioning peg and, in the preferred embodiment, is solid. The positioning peg is hollow, and there may be provided a plurality of the positioning pegs spaced from each other and from the pre-placement peg.

[0010] Other objects, features and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawings.

[0011] 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:

[0012] FIG. 1 a perspective view of a mating connector assembly embodying the concepts of the invention, with the assembly in unmated condition;

[0013] FIG. 2 is a side elevational view of the mating connector assembly as shown in FIG. 1;

[0014] FIG. 3 is a perspective view of the mating connector assembly of FIG. 1, in mated condition;

[0015] FIG. 4 is an exploded perspective view of the backplane connector assembly as seen to the left in FIGS. 1 and 2;

[0016] FIG. 5 is a perspective view of one of the shutter assemblies for the adapter in the backplane connector assembly of FIG. 4;

[0017] FIG. 6 is a perspective view of the other shutter assembly for the adapter;

[0018] 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;

[0019] FIG. 8 is a perspective view of one of the fiber optic connector modules of the backplane connector assembly of FIG. 4;

[0020] FIG. 9 is a perspective view of the housing of the connector module of FIG. 8;

[0021] FIG. 10 is a perspective view showing the assembly procedure of the module of FIG. 8;

[0022] FIG. 11 is an exploded perspective view of the daughterboard connector assembly as seen to the right of FIGS. 1 and 2;

[0023] FIG. 12 is an exploded bottom perspective view of the two-part housing of the daughterboard connector assembly;

[0024] FIG. 13 is a perspective view of the front housing part of the daughterboard connector assembly;

[0025] FIG. 14 is a perspective view of one of the fiber optic connector modules of the daughterboard connector assembly of FIG. 11;

[0026] FIG. 15 is an exploded perspective view of the module of FIG. 14;

[0027] FIG. 16 is a perspective view of the pin keeper of the module of FIG. 14;

[0028] FIG. 17 is a perspective view of the spring pusher member of the module of FIG. 14;

[0029] FIG. 18 is a perspective view showing the assembly of the coil spring to the pin keeper of FIG. 16;

[0030] FIG. 19 is a perspective view showing the assembly of the spring to the pusher member of FIG. 17; and

[0031] FIGS. 20-22 are sequential top plan views, partially broken away, showing the mating of the mating connector assembly of FIGS. 1-3.

[0032] 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.

[0033] 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.

[0034] 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, multifiber 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.

[0035] 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 46aand a rear terminating end 46b.The front mating end is open, as at 46c,and through which the ferrules (described hereinafter) of fiber optic connector modules 38 can project. Terminating end 46bis open, as at 46d,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.

[0036] FIG. 5 shows a shutter assembly, generally designated 50, for closing opening 46bof adapter 46, and FIG. 6 shows a shutter assembly, generally designated 52, for closing mating opening 46cof the adapter. Shutter assembly 50 includes a pair of spring-loaded shutters 50awhich close opening 46don opposite sides of an interior partition 54 (FIG. 4). The shutter members are pivotally mounted on a plate 50bwhich includes a plurality of pegs 50cwhich are press-fit into holes 56 in adapter housing 46. Similarly, shutter 52aof shutter assembly 52 is spring-loaded and is mounted on a plate 52bwhich has a plurality of pegs 52cwhich are press-fit into a plurality of holes 58 in adapter housing 46. Shutters 50aand 52aprovide dust covers for the interior of adapter 36.

[0037] 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 62awhich will engage the surface of the backplane. Mounting holes 64 are spaced on opposite sides of opening 30.

[0038] Still further, each T-nut 60 includes a shank portion 60a and an enlarged head 60b.A mounting flange, generally designed 66, is molded integrally with each opposite side of adapter housing 46. Each flange 66 includes an interior cavity 66awhich receives head portion 60bof one of the T-nuts 60. A passage 66bextends through flange 66 toward backplane 32 in communication with cavity 66afor receiving shank portion 60aof the T-nut. The following parameters should be understood: (1) the dimensions of head portion 60bare smaller than cavity 66aso that the head portion can float within the cavity, (b) the cross dimensions of shank portion 60aare less than the dimensions of passage 66bso that the shank portion can float within the passage and (c) the length of shank portion 60ais 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 32aof backplane 32, the adapter does not become tightened to the backplane and is allowed to float relative thereto. Lastly, passage 66bhas a restricted mouth, as at 66e,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.

[0039] 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 40a(FIG. 8) of the fibers exposed at a mating face 68aof the ferrule. The ferrule includes a pair of alignment holes 68bopening into mating face 68a.The ferrule is captured by a manually manipulatable housing, generally designated 70, which includes a front portion 70awhich actually captures the ferrule, and a rear portion defined by a pair of laterally spaced arms 70bthat are graspable between an operator's fingers. FIG. 10 shows that ferrule 68 has a peripheral flange 68c.The front portion 70aof housing 70 includes a pair of forward latch hooks 70con two opposite sides of the housing and a pair of flexible latch arms 70don the other two opposite sides of the housing. As seen best in FIG. 9, each latch arm 70dincludes an inside chamfered latch hook 70e.Latch hooks 70cengage the front of flange 68cof the ferrule, and latch hooks 70eon latch arms 70dengage the rear edges of flange 68cto hold the ferrule encapsulated within front portion 70aof housing 70.

[0040] 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 70fprojects outwardly from each arm for latching engagement within adapter 36. Each arm 70balso includes an interior channel 70gfor guiding ferrule 68 into front portion 70aof the housing.

[0041] 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 70gof arms 70band through an open rear end 70hof front portion 70aof the housing. The ferrule becomes latched in a position projecting out of an open front end 70i(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.

[0042] FIGS. 11-13 show daughterboard connector assembly 28 to include a two-part housing defined by a front housing partogenerally 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 74awith a latch hook 74bwhich latches behind a front latch shoulder 72a(FIG. 13) when the two housing parts are initially assembled. FIG. 13 also shows a second latch shoulder 72bwhich is located rearwardly of latch shoulder 72a,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.

[0043] 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 72dof front housing part 72 for insertion into pre-placement 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 70dfor 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.

[0044] Still referring to FIG. 12, positioning pegs 84 are provided with crushable ribs 84aon the exterior thereof and which are crushed or deformed when pegs 84 are press-fit into holes 78. Bottom surface 72dof 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 84a,which might be shaved off of positioning pegs 84 when they are press-fit into positioning holes 78. This ensures that bottom surface 72dof front housing part 72 is mounted flush on the flat top surface of daughterboard 34.

[0045] 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 72eof the front housing part. Each flange has an outwardly chamfered or flared distal end 88awhich is engageable by the front edges 90 (FIG. 1) of adapter 36 upon mating of the two connector assemblies. In essence, flared distal ends 88aallow 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 88bon the insides thereof for receiving alignment ribs 48 (FIG. 1) on opposite sides of adapter housing 46. Slots 88bhave flared mouths 88cwhich 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 88athereof in combination with flared mouths 88cof slots 88b,are unique in utilizing a singular structure to allow for misalignment in two different “X” and “Y” directions.

[0046] 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 72d(FIG. 12) of the front housing part. The flange has a bottom hook portion 92aand a top chamfered portion 92b.The bottom hook portion overlaps an edge 94 of daughterboard 34. The top chamfered portion 92bis 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.

[0047] 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 96a(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 96bof 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 102aat a rear end thereof for receiving a front end of coil spring 104, along with a locking flange 102bfor locking with a coil at the front end of the spring. Although not visible in FIG. 16, one of the locking flanges 102bare disposed at each opposite side of receptacle 102aof pin keeper 102.

[0048] Similarly, FIG. 17 shows pusher member 106 to have a front receptacle 106aat a front end thereof for receiving a rear end of coil spring 104. A locking flange 106bis disposed at each opposite side of receptacle 106afor locking with a coil at the rear end of the coil spring.

[0049] 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 104ato lock behind flanges 102b(FIG. 16) of pin keeper 102. This subassembly then is positioned as shown in FIG. 19 so that the opposite open end coil 104b(FIG. 18) is aligned with locking flanges 106bof 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 “3”. 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.

[0050] 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 122aand a forwardly facing chamfer 122b.

[0051] 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 122aof 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 74bon the ends of latch arms 74aat opposite sides of the rear housing part already have latched behind latch shoulders 72a(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 122bat the distal ends of actuator arms 122 of adapter 36 to engage the chamfered distal ends of latch arms 74aof rear housing part 74 and move the latch arms out of engagement with latch shoulders 72a.Latch hooks 74bof latch arms 74anow are free to move between latch shoulders 72aand latch shoulders 72bof 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.

[0052] 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.