Abstract:
A transceiver module assembly includes a printed circuit board ( 4 ), a plurality of transceiver modules, a plurality of electrical connectors ( 6 ) adapted to connect between the plurality of transceiver modules and the printed circuit board, and a shielding cage assembly ( 10 ) which is mounted to the printed circuit board for receiving the transceiver modules and the electrical connectors therein. The shielding cage assembly includes at least one shielding cage ( 21, 22 ), a spacer ( 3 ), and a hanger ( 1 ). The at least one shielding cage and the spacer are mechanically retained in the hanger, and the spacer mechanically engages with the shielding cage for spacing a level to the shielding cage for good air ventilation therethrough.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     This invention relates generally to a cage for shielding components from electromagnetic interference, and more particularly to a shielding cage assembly for arranging a plurality of transceiver modules therein. A copending application filed Jun. 6, 2003 and titled “2×4 SHIELDING CAGE ASSEMBLY ADAPTED FOR MULTIPLE TRANSCEIVER MODULES” and having the same applicant and the same assignee with the instant application, and a contemporaneously filed application having the same title, the applicant and the same assignee with the instant invention, are both referred hereto.  
         [0003]     2. Description of the Related Art  
         [0004]     A transceiver module is a discrete unit used in interface communication equipment, and is normally singly received in a cage that provides shielding against electromagnetic interference (EMI). Prior art shielded transceiver modules are too difficult to assemble densely to a circuit board. Therefore, an inexpensive shielding cage assembly that will allow transceiver modules to be easily and densely mounted on a circuit board is required.  
         [0005]     Referring to  FIG. 6 , a prior art shielding cage assembly  100  for shielding a plurality of transceiver modules (not shown) therein includes a conductive body cage  101 , a conductive cover cage  102  and a plurality of dividing walls  103 , which cooperatively define a plurality of hollow spaces for receiving the transceiver modules therein. Retaining tabs  121 ,  311  are respectively formed on the body cage  101  and on the dividing walls  103 , and engage in a corresponding plurality of slots  24   a ,  24  defined in the cover cage  102  to hold the cover cage  102  to the body cage  101  and to fix the dividing walls  103  between the cover cage  102  and body cage  101 .  
         [0006]     However, this kind of structure cannot satisfy the requirement to stackably mount transceiver modules in interface communication equipment. Therefore, an improved shielding cage assembly that is adapted for stackably receiving a plurality of transceiver modules therein is desired.  
       SUMMARY OF THE INVENTION  
       [0007]     An object of the present invention is to provide a shielding cage assembly for receiving a plurality of transceiver modules therein while allowing good air ventilation.  
         [0008]     A transceiver module assembly includes a printed circuit board, a plurality of transceiver modules, a plurality of electrical connectors adapted to connect between the plurality of transceiver modules and the printed circuit board, and a shielding cage assembly which is mounted to the printed circuit board for receiving the transceiver modules and the electrical connectors therein. The shielding cage assembly includes at least one shielding cage, a spacer, and a hanger. The at least one shielding cage and the spacer are mechanically retained in the hanger, and the spacer mechanically engages with the shielding cage for spacing a level to the shielding cage for good air ventilation therethrough.  
         [0009]     Other objects, advantages and novel features of the present invention will be drawn from the following detailed description of a preferred embodiment of the present invention with attached drawings, in which: 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1  is an assembled view of a shielding cage assembly in accordance with the present invention, mounted to a printed circuit board, with a panel prior to engagement therewith;  
         [0011]      FIG. 2  is a bottom aspect view of the shielding cage assembly of  FIG. 1 ;  
         [0012]      FIG. 3  is a perspective view of a lower shielding cage of the shielding cage assembly of  FIG. 1 , wherein a lower dividing wall is removed;  
         [0013]      FIG. 4  is a perspective view of a spacer of the shielding cage assembly of  FIG. 1 ;  
         [0014]      FIG. 5  is a perspective view of the shielding cage assembly of  FIG. 1 , wherein a hanger is removed; and  
         [0015]      FIG. 6  is a perspective view of a shielding cage assembly according to the prior art.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0016]     Referring to  FIG. 1 , a shielding cage assembly  10  in accordance with the present invention includes a metal hanger  1 , an upper shielding cage  21 , a lower shielding cage  22  and a spacer  3 . The hanger  1  covers the upper and lower shielding cages  21 ,  22  and the spacer  3 .  
         [0017]     Referring also to  FIG. 2 , the hanger  1  is formed from a single sheet of metal and is pressed into a rectangular receptacle box, which includes a top wall  11 , two side walls  12  extending downwardly therefrom and a rear wall  13  extending between the two side walls  12 . An opening (not labeled) is formed by the top and side walls  11 ,  12 , which opening has a rearward boundary at the rear wall  13 . A plurality of mounting pins  124  with needle-eyes therethrough respectively extends downwardly from the side and rear walls  12 ,  13 . A plurality of slits  112  is defined through the top wall  11 , arranged in parallel lines in a frontward to rearward direction. A pair of inward tabs  121  extends inwardly from each side wall  12  to engage with the spacer  3 , which is received in the hanger  1 , to help support a weight of the upper and lower shielding cages  21 ,  22  mounted thereto. A plurality of through holes  110  is defined through all walls  11 ,  12 ,  13  of the hanger  1  for dissipation of heat generated in transceiver modules received in the shielding cage assembly  10 .  
         [0018]     Referring to FIGS.  1  to  3 , the lower shielding cage  22  includes a conductive first portion  221  and a conductive second portion  222 . The first portion  221  covers the second portion  222 . The side walls of the first and second portions  221 ,  222  are interlocking. A pair of retaining tabs  225   a  formed in each side of the second portion  222  is received in a pair of receiving slots  225   b  defined in each side of the first portion  221  for hand soldering together side walls of the first and second portions on both sides. A plurality of notches  215  is defined through the second portion  222  and the first portion  221  arranged in parallel lines in a frontward to rearward direction. A plurality of ground tabs  223  is formed near an opening  220  of the lower shielding cage  22  for making a grounding contact with sides of an aperture  501  of a panel  5  of a system assembly (not shown). A plurality of releasing tabs  224  extends inwardly at an angle from the second portion  222  into the opening  220 . Each releasing tab  224  defines a triangular shaped opening (not labeled) therethrough for securing a transceiver module therein. The releasing tab  224  can be pushed upwardly to remove the transceiver module from the shielding cage assembly  10 .  
         [0019]     A plurality of conductive lower dividing walls  25  is inserted in the lower shielding cage  22  and divides an inner space of the lower shielding cage  22  into a plurality of channels (for example,  FIG. 1  shows a 2×4 format shielding cage assembly having four channels per shielding cage  21 ,  22 ). Each channel receives a transceiver module therein. Each lower dividing wall  25  is elongated, and includes a plurality of mounting pins  251  extending upwardly from an upper, forward edge thereof and a plurality of mounting pins  254  extending downwardly from a lower, forward edge thereof. Each mounting pin  251 ,  254  defines a needle eye therethrough. A protrusion  257  extends from an upper, rearward edge of the dividing wall  25 . A back tab  256  extends rearwardly from an end of the dividing wall  25 . A plurality of through holes  250  is defined through the dividing wall  25  for good air ventilation. The mounting pins  251  pass through the corresponding notches  215  of the second portion  222 , and the mounting pins  254  pass through the corresponding notches  215  of the first portion  221 .  
         [0020]     Referring to  FIG. 5 , the conductive upper shielding cage  21  is substantially similar to the lower shielding cage  22  in structure. A plurality of conductive upper dividing walls  23  is received in the upper shielding cage  21 . The upper dividing walls  23  are similar to the lower dividing walls  25  received in the lower shielding cage  22 , one difference being a plurality of retaining tabs  231  being formed on an upper edge of the upper dividing wall  23  in place of the mounting pins  251  of the lower dividing wall  25 . The retaining tabs  231  pass through notches (not labeled) of a first portion  211 . Similarly, a plurality of mounting pins  234  (not shown) formed on a lower edge of the upper dividing wall  23  and similar to the mounting pins  254  of the lower dividing wall  25  pass through corresponding notches (not shown) defined in a second portion  212 , said notches being similar to the notches  215  in the lower shielding cage  22 . A back tab  236  is similar to the back tab  256  in the lower dividing wall  25 . A protrusion  237  extends from a lower, rearward edge of the dividing wall  23 .  
         [0021]     Referring to  FIG. 4 , the spacer  3  is die-cast and is made of a lightweight material, such as aluminum alloy, zinc alloy, or plastic coated with a conductive material. This kind of spacer  3  has good electrical and thermal conductivities for EMI continuity and heat dissipation. The spacer  3  includes a rectangular base  31  and has a pair of bulges  32  extending from each of two opposite sides of the base  31 , wherein each bulge  32  defines a recess  33  at a bottom of the base  31 . A plurality of extending posts (not labeled), each defining a press-fit hole  34  therethrough, is formed on the base  31  arranged in lines for receiving the mounting pins  234 ,  251  of the upper and lower dividing walls  23 ,  25  therein. A plurality of venting holes  35  is defined through the base  31 . This structure of the spacer  3  allows air to flow freely in all directions around the spacer  3 . A front edge (not labeled) of the spacer  3  provides a stop feature when the shielding cage assembly  10  is inserted in the apertures  501  of the panel  5  of the system assembly.  
         [0022]     Referring to  FIGS. 2 and 5 , a two-port electrical connector  6  is positioned to a rear of each pair of stacked channels of the shielding cage assembly  10 . Each electrical connector  6  includes a front interface  61 , a top surface  62  and a bottom surface  63 . The front interface  61  has two signal ports  615 ,  617 , each with a plurality of signal contacts  635 ,  637  therein for electrical connection with two transceiver modules respectively received in the lower and upper shielding cages  22 ,  21 . Signals transmitted from the two transceiver modules are respectively delivered to a printed circuit board  4  (shown in  FIG. 1 ) through the plurality of signal contacts  635 ,  637  of the signal ports  615  and  617 , wherein the plurality of signal contacts extends from the bottom surface  63  of the electrical connector  6 . A plurality of arch pins  613  protrudes from the front interface  61  and extends out from the bottom surface  63  as ground contacts  633  grounding with the printed circuit board  4 . The arch pins  613  are for contacting with the spacer  3 . A plurality of positioning pins  631  extends from the bottom surface  63  for positioning the electrical connector  6  on the printed circuit board  4 . A plurality of inward pins  625  extends upwardly from the top surface  62 . The inward pins  625  are made of elastic material.  
         [0023]     In assembly, the retaining tabs  231  or mounting pins  234 ,  251 ,  254  of the dividing walls  23 ,  25  are respectively inserted into the first or second portions of the upper and lower shielding cages  21 ,  22 , and the corresponding second or first portions of the shielding cages  21 ,  22  are assembled thereto to create completely assembled upper and lower shielding cages  21 ,  22 . The second portion  222  of the lower shielding cage  22  is oriented upwardly, and the spacer  3  is mounted thereonto, the bulges  32  of the spacer  3  being positioned away from the second portion  222 , and the mounting pins  251  of the lower dividing walls  25  being inserted into the press-fit holes  34  of the spacer  3 . The upper shielding cage  21  fits to the spacer  3 , herein, the mounting pins  234  of the upper dividing wall  23  goes into the press-fit holes  34  of the spacer  3 . The protrusions  237 ,  257  of the dividing walls  23 ,  25  come in complementary pairs. Thus, the upper shielding cage  21  and lower shielding cage  22  are stacked belly-to-belly, and the spacer  3  is sandwiched therebetween for providing good air ventilation. The hanger  1  encloses the upper and lower shielding cages  21 ,  22 , the retaining tabs  231  of the upper shielding cage  21  passing through corresponding slits  112  and hooking onto the hanger  1  for mechanical support and electrical grounding. Each channel formed inside the upper and lower shielding cages  21 ,  22  is used to receive a transceiver module. The electrical connectors  6  are received inside the metal hanger  1  between the dividing walls  23 ,  25  and side walls  12  to a rear of the channels. The inward pins  625  of the electrical connectors  6  are deformed inwardly and pass through the corresponding through holes  110  of the hanger  1 . The bottom surface  63  of each electrical connector  6  is exposed from the hanger  1 . The inward tabs  121  in the side walls  12  of the hanger  1  are inserted into the recesses  33  of the spacer  3 , locking the spacer  3  in the hanger  1 . The back tabs  236 ,  256  of the upper and lower dividing walls  23 ,  25  protrude out of the rear wall  13  of the hanger  1  and are bent at an angle for mechanical retention to and electrical continuity with the hanger  1  for EMI shielding. The mounting pins  124  of the hanger  1  and the mounting pins  254  of the lower dividing walls  25  are pressed into mounting holes (not shown) of the printed circuit board  4  for retaining and grounding, where they can be soldered or otherwise fixed therein. The positioning pins  631  of the electrical connectors  6  are inserted into positioning holes (not shown) of the printed circuit board  4 , and the signal contacts  635 ,  637  and the ground contacts  633  are respectively received into corresponding holes (not shown) of the printed circuit board  4  for transmitting signals or electrical grounding. An assembly of the shielding cage assembly  10 , the electrical connectors  6 , and the printed circuit board  4  is completed.  
         [0024]     The spacer  3  of the present invention has a complex geometry which allows air to flow freely in all directions around the spacer  3  for facilitating the dissipation of heat from a dense assembly of transceiver modules received in the shielding cage assembly  10 . A thickness of the spacer  3  can be easily adjusted for accommodating different spacing applications.  
         [0025]     Although the present invention has been described with specific terms, it should be noted that the described embodiments are not necessarily exclusive, and that various changes and modifications may be made thereto without departing from the scope of the present invention as defined in the appended claims.