Abstract:
A latch mechanism for a pluggable optical module includes a boss in contact with a datum plane of a latch trough to latch and anchor the optical module. When a lever is turned, the boss is turned to press the datum plane and change the relative position to move a sliding member and release the latched and anchored condition of the optical module. The structure is simple and easy to fabricate and assemble. It also is reliable and convenient.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to a latch mechanism for a pluggable optical module and particularly to a latch mechanism for a pluggable optical module that is reliable and convenient.  
       BACKGROUND OF THE INVENTION  
       [0002]     In optical communication applications, the optical transceiver is an important element in a photoelectric transforming interface. Signal transmission speed may range from 155 Mb/s to 1.25 Gb/s or even 10 Gb/s. Various types of packages are available depending on application environments, such as a 1×9 pin, GBIC (GigaBit Interface Converter), SFF (Small Form Factor), SFP (Small Form Factor Pluggable), and the like. The 1×9 pin and SFF adopt a fixed packaging method that are difficult to remove once the module is installed in the system. The GBIC and SFP adopt a pluggable approach that can be removed and replaced after installing in the system.  
         [0003]     In the design of the pluggable module, many factors have to be considered, such as electricity issues while plugging the module, reliability and convenience of the plugging mechanism. For instance, U.S. Pat. Nos. 6,439,918 and 6,533,603 assigned to Finisar Co. disclose a SFP module that has a latching mechanism ramming the bottom of the module through a lever to extend or retract the latching mechanism in the module. U.S. Pat. No. 6,494,623 assigned to Infineon Co. also discloses a SFP release mechanism, which has a lever turnable to press a locking reed of a transceiver to extend a latch of the module to escape a locking reed for releasing the module.  
         [0004]     Another example is U.S. patent application No. 20030171016, which has a lever and elastic latch reeds located on two sides of a module for anchoring. In normal conditions, the elastic latch reeds maintain the anchor condition through a spring located therein. When the lever is moved downwards, the elastic latch reeds are moved outwards and the jutting distal ends thereof are disengaged.  
         [0005]     Those references mostly employ latch mechanisms that are complex and require expensive elements. They also are difficult to fabricate and assemble. For instance, U.S. patent application No. 20030171016 requires two elastic latch reeds and a spring in each of them. It involves too many elements. Fabrication and assembly are difficult.  
       SUMMARY OF THE INVENTION  
       [0006]     In order to solve the aforesaid disadvantages, the present invention aims to provide a latch mechanism for a pluggable optical module that is simply structured, easy to fabricate and assemble, reliable and convenient.  
         [0007]     The latch mechanism for a pluggable optical module according to the invention includes a lever, a sliding member and a latch trough to selectively anchor the optical module on an electronic device. The lever has at least one boss to be mounted in the latch trough and is coupled with the sliding member. By turning the lever, the boss is turned at the same time to slide on a sloped surface on one side of the latch trough to a datum plane of the latch trough and change the relative position of the lever in horizontal direction, and drive the sliding member to move as well so that the optical module may be released from or anchor on the electronic device. Such a mechanism requires fewer elements, and is easier to fabricate and assemble, and also is more stable and reliable.  
         [0008]     The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]      FIG. 1  is a schematic view of the invention coupled with an optical module.  
         [0010]      FIG. 2  is an exploded view of the invention coupled with an optical module.  
         [0011]      FIGS. 3A through 5B  are schematic views of the invention in operating conditions.  
         [0012]      FIGS. 6A through 6H  are schematic views of various embodiments of the boss of the invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0013]     The latch mechanism according to the invention is applicable to any pluggable optical module such as an optical transceiver, light emitter, optical receiver, and the like. The following discussion is based on an optical transceiver.  
         [0014]     Referring to  FIG. 1 , a latch mechanism  20  is adopted for use on an optical module  10  for selectively coupling the optical module  10  on an electronic device (not shown in the drawings). Also referring to  FIG. 2 , the optical module  10  includes an upper lid  11 , a circuit board  12  and a lower lid  13 . The latch mechanism  20  includes a lever  21 , a sliding member  22  and a latch trough  23 . The lever  21  is located on the front end of the optical module  10 , and has a handle  212  and two struts extended from two ends of the handle  212  to fasten to an axle  213 . The axle  213  is coupled with at least one boss  211 . Their functions will be discussed later.  
         [0015]     The sliding member  22  includes two sliding sections  221  and  222  that have one end bridged by a coupling section  223  and other ends with jutting latch sections  2211  and  2221  formed thereon. The latch trough  23  is to hold the boss  211  of the lever  21 .  
         [0016]     The lever  21  is coupled with one end of the optical module  10  in a turnable fashion by nestling the boss  211  in the latch trough  23 . The sliding member  22  clips the optical module  10  and is slidable thereon, and also is coupled with the lever  21 .  
         [0017]     Referring to  FIGS. 3A and 3B , in normal conditions, the sliding sections  221  and  222  of the sliding member  22  clip the optical module  10 , and the boss  211  of the lever  21  has one side in contact with a datum plane  231  of the latch trough  23  and another side in contact with a side wall of the latch trough  23 . As shown in the drawings, the cross section of the boss  211  is formed substantially in a fan shape with two chords defined as a first contact side  2111  and a second contact side  2112 . The bottom side of the latch trough  23  is the datum plane  231 . When the first contact side  2111  is in contact with the datum plane  231 , the second contact side  2112  presses one sidewall of the latch trough  23 . When the second contact side  2112  is in contact with the datum plane  231 , the first contact side  2111  presses another sidewall of the latch trough  23 . When the first contact side  2111  is in contact with the datum plane  231 , the lever  21  and the sliding member  22  are positioned in a normal condition. The latch sections  2211  and  2221  are extended to couple on an electronic device (not shown in the drawings). With the first contact side  2111  of the boss  211  in contact with the datum plane  231 , the module is in a latched and anchored condition without escaping the electronic device.  
         [0018]     When the lever  21  is turned about the axle  213 , it also turns relative to the optical module  10 . The boss  211  also turns, and the first contact side  2111  leaves the datum plane  231 . Referring to  FIGS. 5A and 5B , with the lever and the boss  211  turning continuously, the second contact side  2112  slides over one sidewall of the latch trough  23  and moves to the datum plane  231  to form a contact condition. Meanwhile, the position of the axle  213  is shifted to push the lever  21  to move horizontally, and consequently drags the sliding member  22  coupled on the lever  21  to slide outwards. The latch sections  2211  and  2221  also slide outwards and separate from the electronic device to form a released condition.  
         [0019]     The mechanism set forth above has a simple structure and requires fewer elements. It&#39;s also cheaper, and fabrication and assembly are easier. The sliding sections  221  and  222  may be formed in a reed or become a single element rather than two arms as shown in the drawings. Similarly, the latch sections  2211  and  2221  that are jutting to the left and the right sides serve only as an example and are not the limitation. They may be formed in an up and down manner or become a single latch section. The boss  211  on the axle of the lever aims to slide on the contact sides of the latch trough  23  to generate a horizontal movement for the lever. It may be formed in various shapes such as containing two bosses  211  (referring to  FIGS. 6A and 6B ), or a member with substantially a circular cross section to couple with the axle  213  on an eccentric location (referring to  FIGS. 6C and 6D ), or a member with substantially a square cross section to couple with the axle  213  on an eccentric location (referring to FIGS.  6 E and  6 F); or the latch trough may have a plurality of protrusive elements formed on the datum plane to couple with the boss (referring to  FIGS. 6G and 6H ).  
         [0020]     While the preferred embodiments of the invention have been set forth for the purpose of disclosure, modifications of the disclosed embodiments of the invention as well as other embodiments thereof may occur to those skilled in the art. Accordingly, the appended claims are intended to cover all embodiments, which do not depart from the spirit and scope of the invention.