Abstract:
The present invention relates to a delatching mechanism for an electronic module, such as an opto-electronic transceiver or a copper transceiver, for locking the electronic module in a host cage. The delatching mechanism enables a conventional small form factor (SFP) sized module to be unlatched while a cable remains engaged therein. A manually engageable lever, such as a bail handle, is rotatably connected on one end of a pivoting latch, and includes a projection for abutting against the module housing for distributing the force applied to the bail to one end of the pivoting latch, whereby the other end of the pivoting latch rotates away from engagement with the host cage.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     The present invention claims priority from U.S. Patent Application Ser. No. 60/633,643 filed Dec. 6, 2004, which is incorporated herein by reference for all purposes. 
     
    
     TECHNICAL FIELD  
       [0002]     The present invention relates to a transceiver delatching mechanism, and in particular to pivoting bail delatching mechanism for small form factor pluggable (SFP) optical and copper transceivers.  
       BACKGROUND OF THE INVENTION  
       [0003]     Conventional transceiver delatching mechanisms, such as those disclosed in U.S. Pat. No. 5,901,263 issued May 4, 1999 to Gaio et al; U.S. Pat. No. 6,439,918 issued Aug. 27, 2002 to Togami et al; U.S. Pat. No. 6,789,958 issued Sep. 14, 2004 to Ahrens et al; and U.S. Pat. No. 6,840,680 issued Jan. 11, 2005 to Chiu et al, include a pivoting lever or bail, which when rotated results in a second pivoting element being rotated out of engagement with a host cage or rail system. The bails in the aforementioned devices are rotated through a 90° arc to disengage the latching mechanism, and are therefore prevented from rotating when a fiber optic cable is in position in the optical coupler of the transceiver, because the fiber optic cable will obstruct the cross bar of the bail.  
         [0004]     Other transceiver delatching mechanisms with a pivoting lever or bail and a sliding wedge are disclosed in U.S. Pat. No. 6,692,159 issued Feb. 17, 2004 to Chiu et al; U.S. Pat. No. 6,744,963 issued Jun. 1, 2004 to Hwang; U.S. Pat. No. 6,840,680 issued Jan. 11, 2005 to Chiu et al; U.S. Pat. No. 6,851,867 issued Feb. 8, 2005 to Pang et al; and U.S. Pat. No. 6,916,123 issued Jul. 12, 2005 to Kruger et al. The sliding wedges in the aforementioned devices are not ideal for small form factor transceivers, since they are relatively large and require a specially designed track system for reciprocating therein.  
         [0005]     Another solution for a small form factor delatching mechanism is disclosed in U.S. Pat. No. 6,890,206 issued May 10, 2005 to Distad et al, which discloses a single lever mechanism for bending the cage assembly away from transceiver housing, thereby delatching the transceiver&#39;s latch from the cage&#39;s latch.  
         [0006]     “Copper” transceiver&#39;s are used as short distance patch cables, typically in datacom or telcom equipment rooms, to establish a link between ports in the same room or even in the same cabinet without having to convert to an optical signal and back again to an electrical signal. A multi-conductor electrical cable extends between a pair of copper transceivers, and is soldered at each end thereof directly to the printed circuit board within each of the copper transceivers. Each copper transceiver housing has the size and features of a typical SFP transceiver housing; however, since the electrical cable is permanently fixed within each housing, the typical bail latching mechanism, requiring approximately 90° of rotation is not suitable.  
         [0007]     An object of the present invention is to overcome the shortcomings of the prior art by providing a relatively simple rotating delatching mechanism requiring only a relatively small amount of rotation for delatching a transceiver&#39;s latch from a host cage&#39;s latch.  
       SUMMARY OF THE INVENTION  
       [0008]     Accordingly, the present invention relates to an electronic module for plugging into a host receptacle comprising:  
         [0009]     a housing having a first abutment surface;  
         [0010]     a printed circuit board mounted within the housing having an electrical connector at one end thereof for electrically connecting the module to a mating connector in the host receptacle;  
         [0011]     a latch pivotally connected to the housing about a first axis for releasably holding the module in the host receptacle;  
         [0012]     a lever pivotally connected to the latch about a second axis, the lever including a first camming surface;  
         [0013]     whereby the lever rotates about the second axis until the first camming surface abuts the first abutment surface, thereafter continued rotation of the lever causes rotation of the latch about the first axis for disengaging the latch from the host receptacle. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]     The invention will be described in greater detail with reference to the accompanying drawings which represent preferred embodiments thereof, wherein:  
         [0015]      FIG. 1  is an isometric view of an electronic module with a delatching mechanism in accordance with the present invention;  
         [0016]      FIG. 2  is an isometric view of the electronic module of  FIG. 1  with the delatching mechanism in a release position;  
         [0017]      FIG. 3  is an exploded view of components of the electronic module of  FIGS. 1 and 2  illustrating a first step in an assembly process;  
         [0018]      FIG. 4  is as exploded view of components of the electronic module of FIGS.  1  to  2  illustrating a second step in the assembly process;  
         [0019]      FIG. 5  is as exploded view of components of the electronic module of FIGS.  1  to  2  illustrating a third step in the assembly process;  
         [0020]      FIG. 6  is as exploded view of components of the electronic module of FIGS.  1  to  2  illustrating a third step in the assembly process;  
         [0021]      FIG. 7  is as exploded view of components of the electronic module of FIGS.  1  to  2  illustrating a fourth step in the assembly process;  
         [0022]      FIG. 8  is a perspective view of a copper transceiver patch cable including the electronic module of  FIGS. 1 and 2  on either end thereof;  
         [0023]      FIG. 9  is an isometric view of an electronic module with a delatching mechanism in accordance with another embodiment of the present invention;  
         [0024]      FIG. 10  is an isometric view of an electronic module with the delatching mechanism of  FIG. 9  in the release position;  
         [0025]      FIG. 11  is a side view of an electronic module with the delatching mechanism of  FIGS. 9 and 10  in the release position; and  
         [0026]      FIG. 12  is a front view of a pair of the electronic modules of  FIGS. 1 and 2  adjacent one another sharing a common receptacle cage wall. 
     
    
     DETAILED DESCRIPTION  
       [0027]     With reference to  FIG. 1 , a pluggable electronic module  1  according to the present invention includes a generally rectangular housing  2 , a printed circuit board  3  longitudinally extending therein, a hot-pluggable rear electrical connector  4 , and a front cable connector  5 . The rear electrical connector  4  can take any suitable form depending upon the type of mating electrical connector; however, the illustrated card edge connector is preferred. The illustrated front cable connector  5  is in the form of a block for receiving a multi-conductor cable  10  soldered to the printed circuit board  3 ; however, other front cable connectors can be provided depending upon the function of the module  1 , e.g. a bi-directional opto-electronic transceiver requires a duplex optical connector (LC or SC), a uni-directional opto-electronic module requires a single (LC or SC) connector. Conventional transceivers would also include some form of electro-optical converter, e.g. a photo-detector and/or a laser; however, copper transceivers do not. The electronic module  1  is slid into a host receptacle, e.g. a cage or guide rail, system with an electrical connector corresponding to the electrical connector  4 , which is mounted on a host printed circuit board in a host device.  
         [0028]     A de-latching mechanism  6  is mounted on the bottom of the housing  2 , and includes a latch  7  pivotally connected proximate the middle thereof to the housing  2  about a first axis defined by a first pivoting pin  8 . A lever, preferably in the form of a bail handle  9 , extends around the front end of the housing  2 , and is pivotally connected to a first end of the latch  7  about a second axis, parallel to the first axis, defined by a second pivoting pin  11 . The bail handle  9  includes a pair of side arms  12  and  13 , lower ends of which are pivotally connected to the second pivoting pin  11 , and upper ends of which are connected to a cross bar  14  extending therebetween. The bail handle  9  can be replaced by a single arm or other form of lever. An eccentric projection  16  extends substantially perpendicularly from each of the lower ends of the side arms  12  and  13 , and includes a lower rounded surface  17  and an upper flat camming surface  18  (see  FIG. 6 ). Each projection  16  extends into a recessed area  19 , in the housing  2 , which includes an abutment surface. Preferably, each recessed area  19  is a rectangular step or indentation formed in the front end of the housing  2 , e.g. in the lower front corners of the cable connector block  5 . The lower rounded surface  17  enables the projection  16 , and therefore the bail handle  9 , to act like a first class lever and rotate about the second axis, i.e. the second pivoting pin  11  acting like a fulcrum, without contacting the wall of the housing  2  until the camming surface  18  engages the abutment surface, as seen in  FIG. 2 . When the camming surface  18  engages the abutment surface in the recessed area  19 , the bail handle  9  is not only able to pivot about the second axis; but, further force on the bail handle  9  causes the bail handle  9  to pivot about a third axis defined by the intersection of the camming surface  18  and the abutment surface. Accordingly, the bail handle  9  also becomes a second class lever with the fulcrum at the intersection of the camming surface  18  and the abutment surface, whereby any added force on the bail handle  9  is applied through the pivot pin  11  to the first end of the latch  7 , thereby pivoting the first end of the latch away from the housing  2 . A second end of the latch  7  includes a release arm  20  with a latching finger  21 , which engages a corresponding latching opening on the host cage or guide rail system. Pivoting the first end of the latch  7  away from the housing  2  into a release position ( FIG. 2 ) causes the release arm  20  and the latching finger  21  to detract into an opening in the housing  2 , thereby releasing the latching finger  21  from the latching opening on the host cage enabling the transceiver  1  to be removed therefrom. In the latched position, the latch  7  is recessed into the housing  2  with only the latching finger  21  extending outwardly therefrom. In the unlatched or release position, the first end of the latch  7  is pivoted outwardly from the housing  2 , while the latching finger  21  is detracted further into the housing body, whereby the latching finger  21  no longer extends therefrom.  
         [0029]     With reference to FIGS.  3  to  7 , the electronic module  1 , in the form of a copper transceiver, is assembled by first connecting, e.g. soldering, an end of the multi-conductor cable  10  to the printed circuit board  3 , and mounting the assembly into either a housing bottom  22  or a housing top  23 , which combine to form the housing  2 . The housing bottom  22  and the housing top  23  are at least partially formed from a conductive material, and preferably comprise a cast metal. The housing top  23  includes a thin tail section  24 , and a pair of generally rectangular tapering ears  26 , i.e. tenons, extending therefrom for mating with the housing bottom  22 . The tail section  24  has smaller dimensions, i.e. length and width, than the remainder of the housing top  23 . A U-shaped bar  27  extends across the back of the housing bottom  22  providing a bearing surface and a hold-down bar for the thin tail section  24  of the housing top  23  During assembly, the tail section  24  is inserted under the bar  27 , and the housing top  23  is rotated down until the ears  26  are received in mating recesses  28 , i.e. mortises, in the housing bottom  22  (see  FIG. 4 ). The first pin  8  is then inserted through holes  29  in the sides of the housing bottom  22 , through holes in the ears  26 , and through a bushing extending across the middle of the latch  7 , thereby securing the housing top  23  to the housing bottom  22 , and pivotally mounting the latch  7  to the housing bottom  22 . A spring  31  is positioned between the release arm  20  and the housing bottom  22  to spring bias the release arm  20  into a latched position, whereby a sufficient force must be applied to the bail handle  9  to overcome the spring force of the spring  31  to pivot the latch  7  into an unlatched or release position.  
         [0030]     A solid rectangular conductive projection  25 a, extends outwardly from the housing bottom  22  for contacting the host receptacle and providing electromagnetic interference (EMI) protection. The projection  25   a  extends rearwardly from the cable connector  5  longitudinally along the side of the housing bottom  22 . Preferably, the projection  25   a  includes a sloped rear ramp portion at a leading edger thereof, which gradually decreases in height from the front to the back of the housing  2  to facilitate insertion of the module into a host receptacle, whereby the walls of the cage will engage the ramp portion first and gradually ride up the ramp portion to the main body of the projections. Similarly, solid rectangular projections  25   b  and  25   c , similar to projection  25   a , extend longitudinally along the top of the housing top  23  for contacting a top portion of a host receptacle. Another ramp  25   d  (see  FIG. 12 ) extends along the side of the housing top  23  for added EMI protection. Projections  25   a  and  25   d  make the width to the housing  2  slightly larger than the width of the host receptacle, whereby the projections  25   a  and  25   d  frictionally engage the sides of the host receptacle.  
         [0031]     The next step in the assembly, as illustrated in  FIG. 6 , includes the insertion of the second pivoting pin  11  through a hole in the lower end of the side arm  12 , through a bushing in the end of the latch  7 , and through a hole in the lower end of the side arm  13 .  
         [0032]     Preferably, the first and second pivoting pins  8  and  11  are identical to each other to simplify the supply and the assembly processes. The first and second pivoting pins  8  and  11  are tapered at the insertion end to facilitate insertion and part alignment, and have a flattened head at the other end for engaging a recessed annular wall in the countersunk hole  29 . Moreover, at the head end, the cross section of the first and second pivoting pins  8  and  11  changes from circular to oblong or oval, so that the major diameter of the oval is large enough to form a slight press fit with the hole  29  at the wall of the housing bottom  22  and of the side arm  12 . Accordingly, the final assembly step, see  FIG. 7 , is forcing the head end of the first and second pivoting pins  8  and  11  into engagement with the side of the housing bottom  22  and the side arm  12 , respectively. The first and second pins  8  and  11  can be pressed out, if necessary, without damaging the housing bottom  22  or the first and second pins  8  and  11 , to facilitate repair or the recycling of parts.  
         [0033]     With reference to  FIG. 8 , a patch cable  35  comprises the multi-conductor electrical cable  10  and copper transceivers  1 ′ and  1 ″, similar to electronic module  1 , on either end thereof. Each of the copper transceivers  1 ′ and  1 ″ includes the delatching mechanism  6 , as hereinbefore described with reference to FIGS.  1  to  7 . Since the cable  10  is permanently installed inside the copper transceivers  1 ′ and  1 ″, it is imperative that each bail lever  9  need only be rotated through a small angle before unlatching the latch  7 .  
         [0034]      FIG. 9  to  11  illustrate a second embodiment of a delatching mechanism  46  according to the present invention mounted on an electronic module  50 , including a bail handle  51  with first and second side arms  52  and  53 , and a cross bar  54 , pivoting about the second pivoting pin  11 . The remainder of the electronic module  50  is the same as the electronic module  1 , including the housing top and bottom  23  and  22 , respectively, with a multi-conductor electrical cable  10  extending therefrom. Each side arm  52  and  53  includes an elbow  55  and a horizontal arm section  56 , substantially perpendicular to the main side arm sections  52  and  53 , and extending along the top of the housing top  23 . As can be seen in  FIGS. 10 and 11 , the elbows  55  and the horizontal arm sections  56  effectively make the main side arms section  52  and  53  and the opening therebetween larger enabling the bail handle  51  to be rotated by a larger angle before contacting the cable  10 .  
         [0035]     In highly populated cage assemblies, see  FIG. 12 , a plurality of electronic modules, e.g. transceivers, can be disposed side-by-side, with the adjacent electronic modules  61  and  62  sharing the same cage wall  63 . Unfortunately, when electronic modules are equipped with projections  25   a  and  25   d  at the same height and position on both sides of the housing  2 , i.e. same horizontal plane, insertion and extraction of the modules  1  become very difficult as the projections  25   a  on one side tend to bend the walls of the cage outwardly into the space designated for the projection of the adjacent module. Accordingly, the walls of the host receptacle will squeeze the module therebetween, requiring excessive force for insertion or extraction. A solution to the problem is to vertically offset the projections  25   a  and  25   d  on opposite sides of each housing  2 , so that the projections  25   a  and  25   d  are not in the same horizontal plane. A simple way to provide this vertical offset is to provide the projection  25   a  on one side of the housing bottom  23 , and to provide the ramp  25   d  on the opposite side of the housing top  22 . In this way, as illustrated in  FIG. 12 , the lower projection  25   a  of the module  61  is not directly adjacent the upper projection  25   d  of the module  62 , thereby enabling the cage side wall  63  to bend in two vertically spaced apart places.