Patent Publication Number: US-6340304-B1

Title: Revertible shielding door used in an optical transceiver

Description:
CROSS REFERENCE 
     This application is related to copending U.S. patent application Ser. No. 09/626,542 filed Jul. 27, 2001 and titled “OPTICAL TRANSCEIVER MODULE” which has common inventors and the same assignee of this application. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of The Invention 
     The present invention relates to a revertible shielding door used in an optical transceiver module and the optical transceiver module using the same, particularly to a revertible shielding door utilizing a self-resilient structure to return to its original closed position after an inserted plug is withdrawn from the optical transceiver module. 
     2. The Prior Art 
     Laser diodes are basic components used in an optical transceiver for converting electrical signals into decoded photo signals. Normally, the photo signal emitted from the laser diode is harmful to human eyes. Therefore, in U.S. Pat. No. 5,879,173, a shielding door is provided in an entry of a receptacle assembly which receives the optical transceiver. A spring such as a torsion spring is additionally mounted on a pivotable post of the shielding door for returning the shielding door to its closed position parallel to the front face of the receptacle assembly&#39;s entry. However, the spring is apt to escape from its constant position due to the frequent open/close of the shielding door. Therefore, it is requisite to provide a new shielding door having a self-resilient structure without the need of an extra spring. 
     SUMMARY OF THE INVENTION 
     The primary purpose of the present invention is to provide a self-resilient shielding door for protect users from being hurt by radiation emitted from an optical transceiver module when a complementary plug is pulled out from the optical transceiver module. 
     According to one aspect of the present invention there is provided a revertible shielding door pivotably and resiliently connected to a base. The revertible shielding door comprises a pivot pivotably associated with the base. Two shielding plates extend from the pivot and they are coplanar with each other. Two spring arms extend from two ends of the pivot and each spring arm has a first section coplanar with the shielding plates and a second section extending from the first section and horizontally offset from the first section at a terminated end firmly fixed to the base. 
     According to another aspect of the present invention there is provided a transceiver module comprising a base having three in-lined supports extending upright from a front section thereof and two stands extending upright from an intermediate section thereof. A revertible shielding door comprises a pivot pivotably associated with the three in-lined supports. Two shielding plates extend from the pivot and they are rotatable between the three in-lined supports. Two spring arms extending from two ends of the pivot and each spring arm having a first section parallel to the in-lined supports and a second section extending from the first section and horizontally offset from the first section at a terminated end which is firmly fixed to one of the two stands. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded view of a transceiver module in accordance with the present invention; 
     FIG. 2 is a similar view to FIG. 1 except that some of the parts have been assembled; 
     FIG. 3 is a partially assembled view of FIG. 1; 
     FIG. 4A is an enlarged view of the interconnection bracket of FIG. 1; 
     FIG. 4B is an alternative embodiment of the interconnection bracket; 
     FIG. 4C is a schematic cross-sectional view of the assembled transceiver module of FIG. 1; 
     FIG. 5 is a partially perspective view of the transceiver module and a complementary fiber connector to be plugged into the transceiver; 
     FIG. 6 is a schematic view of FIG. 5 showing the relation between a shielding plate and a spring arm before the complementary fiber connector has been plugged into the transceiver; 
     FIG. 7 is an assembled view between the transceiver and the complementary fiber connector of FIG. 5; and 
     FIG. 8 is a schematic view of FIG. 7 showing the relation between the shielding plate and the spring arm after the complementary fiber connector has been fully plugged into the transceiver. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 1 and 2, an optical transceiver in accordance with the present invention comprises a base  1 , a shielding door  2  pivotally and resiliently fixed to the base  1 , an interconnection bracket  3  detachably fixed to the base  1 , a printed circuit board  5  fixed to the interconnection bracket  3  and firmly positioned in the base  1 , a pair of resilient latches  7  fixed to two opposite sides of the base  1 , and a cover  8  detachably mounted on the base  1 . 
     The base  1  has a bottom plate  19 , a pair of front side walls  11  and a pair of rear side walls  12  extending from two sides of the bottom plate  19 , and each front side wall  11  and rear side wall  12  formed at the same side are connected to each other via an interconnection wall  121 . 
     A reception socket  13  is formed by overlapped and spaced-apart sections of the front side wall  11  and the rear side wall  12 , so that the reception socket  13  exposes to exterior from its top and front faces. A cutout  130  is defined in the reception socket  13 . Specifically, the cutout  130  is formed at the outer periphery of the front side wall  11  around the interconnection wall  121 . 
     Two stands  14  extend upward from the bottom plate  19  and are respectively integrated with inner surfaces of the front side walls  11 . Each stand  14  has a positioning post  141  extends upward therefrom. A pair of positioning ribs  15  is formed on an inner surface of each front side wall  11 , wherein the ribs  15  are parallel to each other. Therefore, there are opposite pairs of positioning ribs  15  formed on the front side walls  11 , yet only one pair is shown in the drawing. 
     A boss  16  is formed on an inner surface of the rear side wall  12  and a vertical hole  160  is defined in the boss  16 . A positioning step  17  is formed below the boss  16 . A hollow post  18  extends upward from the bottom plate  19  and a peripheral seat  181  is formed at a periphery portion of the hollow post  18 . A front central support  19 A is formed on the bottom plate  19  near a front edge  191  thereof. Two front side supports llA are formed on the bottom plate  19  and respectively integrated with inner surface of each front sidewall  11 . Pivot holes  190 ,  110  are respectively formed in the front central support  19 A and the front side supports  11 A, and the pivot holes  190 ,  110  are co-linear. A positioning space  112  is defined between each pair of the front side support  11 A and the stand  14  which are integrated with the same front side wall  11 . Two shallow recesses  192  (only one is shown) are formed in the bottom plate  19  substantially between the opposite pairs of the positioning ribs  15 . 
     The shielding door  2  comprises a pivot  21  pivotably positioned in the in-line holes  110 ,  190  of the front side supports  11 A and front central support  19 A. Two shielding plates  22  extending from the pivot  21  are coplanar with each other. Two spring arms  23  extend from near two ends of the pivot  21 . Each spring arm  23  has a vertical section  231  coplanar with the shielding plate  22  and a curved section  232  integrated with the vertical section  231  and extending away from the vertical section  231  horizontally for an offset distance. A hole  230  is defined at a terminated end of the curved section  232 . The spring arm  23  is fixed to the stand  14  by engaging the hole  230  thereof with the positioning post  141 . 
     Also referring to FIG. 4A, the interconnection bracket  3  comprises a housing  31  defining two cavities  30  therein for receiving a photo diode  41  and a laser diode  42 . Each cavity  30  has a shoulder  36  functioning as a stopper when the corresponding diode  41  or  42  are inserted into the cavity  30 . The photo diode  41  and the laser diode  42  have similar outlook each having a circular groove  410 ,  420  defined in the periphery thereof and each having conductive leads  411 ,  421  extending from a rear face thereof. The housing  31  has two pairs of spring hooks  32  extending from a front face thereof and two rear plates  311  extending from a rear face thereof. Each rear plate  311  defines a channel  310  in an inner surface thereof. A pair of retention hooks  33  proximate to each other extends from a rear face of the housing  31 . Ribs  35  are formed in opposite sides of the housing  31  for simultaneously engaging with opposite pairs of the positioning ribs  15  formed in the front side walls  11  of the base  1  when the interconnection bracket  3  is fixed to the base  1 . 
     Referring to FIG. 4B, an alternative embodiment of the interconnection bracket  3  is shown, wherein most of the structure of the alternative embodiment is identical to that of the embodiment shown in FIG. 4A except that each cavity  30  has two retention ribs  37  formed in a same virtual plane for rotatably engaging with the circular groove  410  ( 420 ) of the photo diode  41  (or laser diode  42 ). With the additional retention ribs  37 , the diodes  41 ,  42  can be further retained in the cavities  30  of the interconnection bracket  3 . 
     The printed circuit board  5  comprises a front narrow section  51  and a rear wide section  52  along a length wise direction thereof. Solder pads  511  are formed on the printed circuit board  5  near a front edge thereof for soldering with the conductive leads  411 ,  421  of the photo diode  41  and the laser diode  42 . A slit  500  is defined in the front narrow section  51  for engaging with the pair of retention hooks  33  when the front edge of the printed circuit board  5  is moved into between the retention hooks  33 . A fixing hole  50  is defined in the front narrow section  51  for retaining around the hollow post  18 , with the periphery thereof being seated on the peripheral seat  181  around the hollow post  18  as shown in FIG.  4 C. Two semi-circular cutouts  520  are defined in opposite sides of the rear wide section  52  for mating with peripheries of the bosses  16  of the base  1 . A rear connector  6  such as an SCA 2  connector is connected to a rear edge of the printed circuit board  5  by straddle mounting soldering. 
     The resilient latch  7  has a retention section  70  having a hook end  73  for being engaged with the cutout  130  of the reception socket  13  when the retention section  70  is inserted into the socket  13  of the base  1 . A bent-out section  72  is integrated with the retention section  70 , yet not in alignment with the former but bent out for a predetermined angle for creating a horizontal offset with respect to the retention section  70 . An engagement section  75  is integrated with the bent-out section and parallel to the retention section  70 . The engagement section  75  has a ratchet  755  for engaging with a slot of an external guide rail or receptacle (not shown) which removably receives the optical transceiver module therein. A handle section  71  is integrated with the engagement section  75  and has teeth formed thereon for increasing friction when a user operates thereon. 
     The cover  8  is a metal plate having a shallow groove  88  defined in most area thereof, a hole  80  defined in the shallow groove  88  for being connected to the hollow post  18  of the base  1  via a screw  81  as shown in FIG. 4C. A cap  82  is formed at a front edge of the cover  8  for being located on aligned front top surfaces of the front side supports  11 A and the front central support  19 A. A reception groove  820  is defined beside the cap  82  for covering the pivot  21  of the shielding door  2  while allowing the pivot  21  to rotate therein. A pair of posts  86  (only one is shown) extends downward from opposite sides of the cover  8  for being inserted into the vertical holes  160  of the bosses  16  when the cover  8  is mounted on the base  1 . A pair of middle flanges  83  (only one is shown) extends downward from opposite sides of the cover  8  for being retained in the sockets  13  when the cover  8  is mounted on the base  1 . A pair of front flanges  85  (only one is shown) extends downward from opposite sides of the cover  8  for being retained in the positioning space  112  of the base  1  when the cover  8  is mounted on the base  1 . A tape  9  is attached on the surface of the shallow groove  88  after the cover  8  has been firmly mounted on the base  1 . 
     In assembling, the photo diode  41  and the laser diode  42  are firstly fixed in the interconnection bracket  3  by inserting the photo diode  41  and the laser diode  42  into the cavities  30  of the interconnection bracket  3 , appropriately rotating the diodes  41 ,  42  until the conductive leads  411 ,  421  are oriented in a ready-to-solder position with respect to the printed circuit board  5 . For the alternative embodiment of the interconnection bracket  3  shown in FIG. 4B, the first assembling step is similar except that the diodes  41 ,  42  have to be inserted into the cavities  30  by additional force for fixing the ribs  37  in the circular grooves  410 ,  420  of the diodes  41 ,  42  so that the circular grooves  410 ,  420  can rotatably engage with the retention ribs  37 . Secondly, the printed circuit board  5  is moved forward to the interconnection bracket  3  so that the slit  500  can be engaged with the retention hooks  33  and the conductive leads  411 ,  421  can be in contact with the solder pads  511 . Thirdly, perform a soldering procedure in a bake for soldering the conductive leads  411 ,  421  to the solder pads  511 . Fourthly, put the printed circuit board  5  and the interconnection bracket  3  down into the base  1  in position, with the rib  35  of the interconnection bracket  3  being retained in the pair of ribs  15 , a lower periphery of each diode  41 ,  42  being seated in the shallow recess  192 , the fixing hole  50  being engaged with the hollow post  18 , the semi-circular cutout  520  engaging with the boss  16 , and the rear wide section  52  being seated on the positioning steps  17 . Fifthly, install the shielding door  2  in the base  1  by putting the pivot  21  in the pivot holes  110 ,  190  and engaging the hole  230  of the spring arm  23  with the positioning post  141 . Sixthly, inserting the retention section  70  of the resilient latch  7  into the reception socket  13  of the base  1 , with the hook end  73  of the resilient latch  7  being engaged with the cutout  130  formed in the reception socket  13 . The configuration after the above six steps can be referred to FIG.  3 . Finally, in a seventh step, the cover  8  is mounted on the base  1 , with the hole  80  thereof being firmly secured to the hollow post  18  via the screw  81 , the post  86  being retained in the vertical hole  160  of the boss  16 , the middle flange  83  being positioned in the reception socket  13  and in contact with the retention section  70  of the resilient latch  7 , and the front flange  85  being retained in the positioning space  112 . 
     The activity and function of the shielding door  2  may be referred to FIGS. 5 to  8 . Firstly, referring to FIGS. 5 and 6, a fiber connector  27  connected with two fiber cables  28  and having two plugs  29  is ready for insertion into the optical transceiver. Before the plugs  29  are inserted into the optical transceiver module, the shielding plate  22  is maintained vertical to the base  1  and the spring arm  23  remains in its original shape. After the plugs  29  are inserted into the optical transceiver, the pivot  21  is forced to rotate for substantially ninety degrees causing the shielding plate  22  to remain parallel to the base  1 , meanwhile the spring arm  23  is deformed and reserves tension therein, as shown in FIG. 7 and 8. When the fiber connector  27  is withdrawn from the optical transceiver, the spring arms  23  recover to their normal form forcing the pivot  21  to rotate for ninety degrees and causes the shielding plates  22  to recover vertical to the base  1 . 
     While the present invention has been described with reference to a specific embodiment, the description is illustrative of the invention and is not to be construed as limiting the invention. Therefore, various modifications to the present invention can be made to the preferred embodiment by those skilled in the art without departing from the true spirit and scope of the invention as defined by the appended claims.