Abstract:
A monolithic bail-delatch mechanism is provided for a module plugged into a cage. The bail-delatch mechanism is a single monolithic unit that includes a living hinge connecting a bail and a delatch clip. The living hinge, the bail, and the delatch clip may be made of a single injection molded plastic part. The bail may include cantilever hooks for securing the bail against the module in a latched position. The delatch clip may include a spring mechanism having two spring arms for locking the bail-delatch mechanism to the module, and a delatch fork having tines with wedges for releasing a post of the module from a latch tab of the cage.

Description:
DESCRIPTION OF RELATED ART  
       [0001]     Small form factor pluggable (SFP) fiber optic and copper transceivers often include a bail-delatch mechanism that eases the process of unplugging the transceiver. Conventional bail-delatch mechanisms include metal wire bails and multi-piece injection molded plastic bail-delatch systems.  
       SUMMARY  
       [0002]     In one embodiment of the invention, a monolithic bail-delatch mechanism is provided for a module plugged into a cage. The bail-delatch mechanism is a single monolithic unit that includes a living hinge connecting a bail and a delatch clip. The living hinge, the bail, and the delatch clip may be made of a single injection molded plastic part. The bail may include cantilever hooks for securing the bail against the module in a latched position. The delatch clip may include a spring mechanism having two spring arms for locking the bail-delatch mechanism to the module, and a delatch fork having tines with wedges for releasing a post of the module from a latch tab of the cage. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0003]      FIGS. 1 and 2  illustrate an exemplary bail-delatch mechanism.  
         [0004]      FIGS. 3 and 4  illustrate an exemplary delatch clip.  
         [0005]      FIG. 5  illustrates an exemplary module for receiving the exemplary bail-delatch mechanism of  FIGS. 1 and 2 .  
         [0006]      FIG. 6  illustrates a delatch mechanism in one embodiment of the invention.  
         [0007]      FIG. 7  illustrates the bail-delatch mechanism of  FIG. 6  inserted into a module in one embodiment of the invention.  
     
    
       [0008]     Use of the same reference numbers in different figures indicates similar or identical elements.  
       DETAILED DESCRIPTION  
       [0009]      FIG. 1  is a cut-away, perspective view of an exemplary system including a pluggable module  210 , a cage  120 , and a bail-delatch mechanism  230  in a latched configuration. In  FIG. 1 , half of cage  120  is cut away to better show module  210  and bail-delatch mechanism  230 , and part of module  210  is also cut away to better illustrate bail-delatch mechanism  230 . Standard features associated with optical fibers and transceivers in module  210  are simplified in the drawings to improve the clarity of the drawings.  
         [0010]     Cage  120  can be a standard cage and generally complies with an MSA (Multisource Agreement) agreement such as SFF (Small Form Factor) committee&#39;s INF-8074i “SFP Transceiver” document. In particular, cage  120  includes a latch tab  122  (half of which is shown in  FIG. 1 ) including a hole  124  that can accommodate a post  214  positioned according to the requirements of the pertinent MSA. Although  FIG. 1  illustrates cage  120  as being isolated, cage  120  would typically be one of several substantially identical cages arranged in a dense array of cages. Such cages are well known in the art and are available commercially from suppliers such as Amp/Tyco International, Picolight Inc., or Molex Inc. Other known and suitable cage structures for module  210  can accommodate a row of (e.g., four) immediately adjacent modules.  
         [0011]     Module  210  has dimensions in compliance with the pertinent MSA and further includes notches  216  and pockets  212  that accommodate portions of bail-delatch mechanism  230 . In one example, module  210  is made of a metal such as zinc ZA8, which can be cast to create fine features necessary for bail-delatch mechanism  230  and for fiber optic and electrical components (not shown) contained in module  210 . Alternatively, module  210  can be injection molded using a high temperature thermal plastic material such as one of materials from the ULTEM family of plastics from General Electric, Co.  
         [0012]     As shown in  FIG. 1 , bail-delatch mechanism  230  includes an integrated structure  240  (hereafter “delatch clip  240 ”) and a bail  250 . Delatch clip  240  can be molded or machined and includes features such as ridges  242  and  244 , spring arms  246 , and wedges  248 . Bail  250  is friction fit through a hole in delatch clip  240  and can be flipped down as shown in  FIG. 1  to keep bail out of the way, or flipped up as shown in  FIG. 2  to extend out and facilitate pulling on bail-delatch mechanism  230  during removal of module  210 . Ridges  242  and  244  also provide grip points for pulling bail-delatch mechanism  230  when bail  250  is down or is otherwise inconvenient for gripping. An LC (Lucent connector) fiber connector (not shown) can attach to module  210  through the center of bail  250 .  
         [0013]     Spring arms  246  have ends in notches  216  in module  210  (only one is visible in  FIGS. 1 and 2 ). Spring arms  246  flex in response to a pulling force on bail-delatch mechanism  230  and permit a limited range of motion for bail-delatch mechanism  230  relative to module  210 .  
         [0014]     In the latched configuration, spring arms  246  can be uncompressed or have some spring loading, and wedges  248  reside in pockets  212  in module  210 . Above wedges  248  is latch tab  122 . Through latch tab  122  is hole  124 , in which post  214  resides when module  210  is latched in cage  120 .  
         [0015]     To remove module  210  from cage  120 , an operator pulls out on bail-delatch mechanism  230  via bail  250  or ridges  242  and/or  244 . Initial pulling bends/flexes spring arms  246  and slides wedges  248  out of their respective pockets  212 . As wedges  248  rise out of pockets  212 , wedges  248  push up on latch tab  122 .  
         [0016]      FIG. 2  shows a configuration where spring arms  246  have reached a limit of their compression and wedges  248  have lifted latch tab  122  above post  214 . In the example of  FIGS. 1 and 2 , spring arms  246  are at angles such that pulling on delatch clip  240  flexes spring arms  246  about their respective bases and extends the ends of spring arms  246  further into notches  216  in module  210 . Accordingly, pulling more firmly engages spring arms  246  in notches  216 . In the illustrated configuration of  FIG. 2B , spring arms  246  contact fixed portions  247  (only one is labeled) of bail-delatch mechanism  230  and cannot flex further. The pulling force thus acts on module  210  to slide module  210  out of cage  120 .  
         [0017]      FIGS. 3 and 4  respectively show top and side view of delatch clip  240  when uncompressed. As noted above, when an operator pulls on delatch clip  240 , spring arms  246 , which are in notches in module  210 , flex until encountering surfaces  247 , which prevent further flexing of spring arms  246  and thereby transfer the pulling force to module  210 . As illustrated, spring arms  246  are crossed at matching angles to provide a balanced force on module  210 .  
         [0018]     In one example, delatch clip  240  is made of a polymer material that can be molded with the required features and can withstand the temperature range specified for module  210 . One suitable material is Zytel FR15 NC010 from Dupont, but many other materials can be used. In one example, the material of delatch clip  240  should have a flexural modulus in a range between about 3000 to 5000 MPa, have a minimum tensile strength of 60 MPa, be able to withstand at least a 8.5% elongation, have a heat deflection temperature of at least 70 .degree. C., and have a UL-V0 rated flammability.  
         [0019]      FIG. 5  is a top view of a portion of module  210  associated with bail-delatch mechanism  230 . As illustrated, module  210  includes a channel  430  having guide rails along both sides to guide movement of delatch clip  240 . The dimensions of channel  430  and the associated guide rails can be the same as the dimensions of the matching structures in conventional modules so that module  210  can be used with either a pull-to-detach mechanism in accordance with the current invention or a standard push-to-detach mechanism. However, along channel  430 , module  210  includes notches  216  that are offset from each other to accommodate spring arms  246  of delatch clip  240  ( FIG. 3 ).  
         [0020]     When assembling module  210  of  FIG. 5  and delatch clip  240  of  FIG. 3  to form the assembly of  FIG. 1 , spring arms  246  can be lifted above the top of module  210  while sliding delatch clip  240  into channel  430 . Spring arms  246  drop down into notches  216  when delatch clip  240  reaches the latched position.  
         [0021]     Module  210  also includes pockets  212  in which respective wedges  248  reside when in the latched position. In one example, pockets  212  include an incline at an angle (e.g., 24 degree) that is less than or equal to a bottom angle (e.g., 30 degree) of wedges  248  so that wedges  248  slide along their heels during the delatch operation that lifts latch tab  122 .  
         [0022]     As noted in the description of  FIG. 1 , bail-delatch mechanism  230  has a handle including bail  250  and ridges  242  and  244  that permit an operator to pull on the bail-delatch mechanism  230  and remove module  210 . Bail  250  has a friction fit with delatch clip  240  so that bail  250  remains in any position (e.g., up or down) that the operator prefers. The delatch mechanism could alternatively employ a variety of other types of handles. For example, ridges  242  and  244  could be omitted in a system that relies solely on bail  250  when removing module  210 .  
         [0023]      FIG. 6  illustrates a monolithic bail-delatch mechanism  630  that can be used to release module  210  from cage  120  in one embodiment of the invention. In one embodiment, bail-delatch mechanism  630  is formed by plastic injection molding using a material such as nylon or polypropylene.  
         [0024]     Bail-delatch mechanism  630  includes a living hinge  632  between a delatch clip  640  and a bail  650 . Living hinge  632  is a thin section of plastic that allows bail  650  to pivot between a latched position and an unlatched position.  
         [0025]     Delatch clip  640  is similar to delatch clip  240  ( FIGS. 3 and 4 ). In one embodiment, delatch clip  640  includes a spring mechanism having spring arms  246 , and a delatch fork having tines with wedges  248 .  
         [0026]     Bail  650  is similar to bail  250  ( FIGS. 1 and 2 ). In one embodiment, bail  650  includes cantilever hooks  652  for maintaining bail  650  in the latched position. Referring to  FIG. 7 , bail  650  is pivoted upward at living hinge  632  in the latched position. Cantilever hooks  652  then engage notches  654  (only one is visible) in module  210  to secure bail  650  in the latched position. Alternatively, bail-delatch mechanism  630  can be formed with bail  650  in the latched position (e.g., perpendicular to delatch clip  640 ) so that bail  650  would naturally rest against module  210 .  
         [0027]     Bail-delatch mechanism  630  offers many advantages over conventional bail-delatch systems with metal wire bails and multi-piece injection molded plastic bail-delatch systems. With a monolithic construction, bail-delatch mechanism  630  lowers cost by minimizing part-count and eliminating assembly. With an all-plastic construction, bail-delatch mechanism  630  also eliminates the issue of transmission of electrostatic discharge (ESD) energy into the module when the exposed metal bail is struck directly by contact ESD.  
         [0028]     Various other adaptations and combinations of features of the embodiments disclosed are within the scope of the invention. Numerous embodiments are encompassed by the following claims.