Abstract:
The present invention provides an electrical connector ( 100 ) comprising a housing assembly ( 10, 20 ) defining a slot, a number of contacts ( 30 ) assembled to the housing assembly ( 10, 20 ), a carriage ( 80 ) up and down moveably assembled in the slot; and a latch arm ( 50 ) being pivotally mounted to an end of the carriage ( 80 ) and being up and down moveable with the carriage ( 80 ), wherein the latch arm ( 50 ) being pivotally moveable coupled with a downward movement together with the carriage ( 80 ), in response to insertion of a daughter card into the slot, from an upper position to a lower position.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims priority under 35 U.S.C. §119(e) of U.S. Provisional Patent Application No. 60/740,472 filed Nov. 28, 2005. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a card edge connector for an electronic card, and more particularly, to a card edge connector wherein a low or zero insertion force is applied to the electronic card when the electrical card is inserted into the card edge connector.  
         [0004]     2. Description of the Prior Art  
         [0005]     U.S. Pat. No. 4,553,804 issued to Scott et al. on Nov. 19, 1985, discloses a related conventional card edge connector. The card edge connector comprises an elongated outer housing having a channel extending in a longitudinal direction, a plurality of contacts mounted on said outer housing on either side of said channel, said contacts having lower end portions projecting exteriorly of said outer housing through the bottom of said channel, and upper portions interior said outer housing adapted to contact opposite sides of a circuit board, an inner housing mounted interior said outer housing for movement inwardly and outwardly along a vertical direction normal to the longitudinal direction, an ovally shaped cam having an axis of rotation extending in the longitudinal direction, said cam being adapted to be rotated from a first position presenting a narrow cross section in the vertical direction to a second position presenting a wider cross section in the vertical direction, a pair of first cam engaging surfaces and a pair of second cam engaging surfaces, said inner and outer housings each including respective first and second cam engaging surfaces, said first surfaces being diametrically opposed along the vertical direction and adapted to be moved apart when said cam is rotated from said first position, said second surfaces being laterally displaced from said first surfaces along the direction of rotation of said cam and adapted to be moved apart when said cam is rotated from said second position, said inner housing including means adapted to engage and urge upper portions of said contacts apart when said cam is rotated from one of said positions to the other of said positions whereby removal or insertion of a circuit board is permitted.  
         [0006]     However, when the cam is rotated from one of the positions to the other of the positions, a force is applied to the inner housing which may cause imbalance of the inner housing. Furthermore, there is no sealing protection for contact mating portions of the contacts when PCB is not installed.  
         [0007]     Hence, an improved card edge connector is needed to solve the above problems.  
       OBJECTS OF THE INVENTION  
       [0008]     A main object of the present invention is to provide a card edge connector which provides physical sealing to contact mating faces of the contacts, anytime that a PCB is not installed.  
         [0009]     Another object of the present invention is to provide a card edge connector having contacts whose Contact durability is improved.  
         [0010]     Another object of the present invention is to provide a card edge connector providing a reducing insertion force by approximately 40% when a daughter card is inserted in.  
         [0011]     Still another object of the present invention is to provide a card edge connector which provides 100% contact normal force only at the end of PCB insertion.  
         [0012]     Other objects, advantages and novel features of the invention will become more apparent from the following detailed description of the present embodiment when taken in conjunction with the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]     The features of this invention which are believed to be novel are set forth with particularity in the appended claims. The invention, together with its objects and the advantages thereof, may be best understood by reference to the following description taken in conjunction with the accompanying drawings, in which like reference numerals identify like elements in the figures and in which:  
         [0014]      FIG. 1  is a perspective view of a card edge connector of an embodiment according to the present invention, with a part of a housing half cut off;  
         [0015]      FIG. 2  is an exploded view of a card edge connector shown in  FIG. 1 ;  
         [0016]      FIG. 3  is a perspective view of a housing half shown in  FIG. 2 ;  
         [0017]      FIG. 4  is a scaled perspective view of the housing half shown in  FIG. 3 ;  
         [0018]      FIG. 5  is a perspective view of a molded carriage shown in  FIG. 2 ;  
         [0019]      FIG. 6  is a perspective view of a latch/release arm shown in  FIG. 2 ;  
         [0020]      FIG. 7  is a perspective view of a center bar shown in  FIG. 2 ;  
         [0021]      FIG. 8  is a side view of a contact strip in  FIG. 2 ;  
         [0022]      FIG. 9  is a perspective view of the housing half shown in  FIG. 3 , with a contact strip arranged therein.  
         [0023]      FIG. 10  is a perspective view of the subassembly shown in  FIG. 9  with a piece of epoxy bead applied onto the contact strip.  
         [0024]      FIG. 11  is a perspective view of the subassembly shown in  FIG. 10  with the center bar is disposed thereon.  
         [0025]      FIG. 12  is a perspective view of a carriage subassembly of the molded carriage shown in  FIG. 5  and the latch/release arm shown in  FIG. 6 .  
         [0026]      FIG. 13  is a perspective view of the subassembly shown in  FIG. 11  with the carriage subassembly in position.  
         [0027]      FIG. 14  is another perspective view of a final assembly connector shown in  FIG. 1 ;  
         [0028]      FIG. 15  is a cross sectional view of the card edge connector shown in  FIG. 1 , taken along a line XV-XV, except that the carriage subassembly arrives at its highest position;  
         [0029]      FIG. 16  is a view similar to  FIG. 15 , except that a PCB is partly inserted therein and the latch/release arms come to a vertical direction; and  
         [0030]      FIG. 17  is a view similar to  FIG. 15 , except that a PCB is fully inserted thereinto and the carriage subassembly arrives at its lowest position. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0031]     Reference will now be made to the drawing figures to describe the present invention in detail.  
         [0032]     Referring to  FIGS. 1-2 , a card edge connector  100  of an embodiment according to the present invention is shown. The connector  100  is formed as an elongated and narrow body which defines a lengthwise direction, a widthwise direction perpendicular to the lengthwise direction and a vertical direction orthogonal to both the aforementioned directions. The connector  100  includes two elongated molded housing halves  10  and  20  cooperatively forming the body of the connector  100 , two contact strips  30  arranged along the lengthwise direction of the molded housing halves  10  and  20 , two molded latch arms  50 , a molded center bar  70 , a molded carriage  80  and two pieces of epoxy beads  90  (shown in  FIG. 10 ).  
         [0033]     Referring to  FIGS. 3-4 , the molded housing half  10  is shown. The housing half  10  forms a long sidewall  12  and two end walls  14  perpendicularly extending from opposite ends of the sidewall  12 , which cooperatively define a center slot (not labeled) for receiving the two molded latch arms  50 , the molded center bar  70 , the molded carriage  80  and an inserted card  400  (shown in  FIG. 17 ). The sidewall  12  defines a row of contact receiving slots  126  for receiving the contact strips  30  and a pair of guiding grooves  122  at opposite ends of the row of contact receiving slots  126 . The guiding groove  122  extends in the vertical direction and ends in a stop surface  128  facing downwardly. The sidewall  12  further forms a respective resting tab  124  and a number of fingers  127 . Each of the resting tabs  124  is located between one of the guiding grooves  122  and the nearest contact receiving slot  126  and defines a resting surface  125  facing upwardly. The fingers  127  correspond to lower ends of every other contact receiving slots  126  so that, between every two adjacent fingers, a respective recessed lower end portion  129  of the slot  126  is formed. Each of the end walls  14  protrudes inwardly a cam protrusion  144  having a slope cam surface  148  facing the center slot and extending outwardly and downwardly. The end wall  14  forms a vertical end face and a pair of guiding posts  142  protruding in the width direction therefrom.  
         [0034]     The other housing half  20  is the same as the housing half  10  except that a pair of guiding holes (not shown) takes the places of the guiding posts  142 .  
         [0035]     Referring to  FIG. 5 , the molded carriage  80  is shown as an elongated element parallel to the lengthwise direction. The molded carriage  80  defines a pair of opposite side faces  82  and a row of guiding slots  822  extending vertically in a center portion of either side face  82  and forms a pair of guiding towers  824  at two opposite ends. The rows of guiding slots  822  of the molded carriage  80  is corresponding to the rows of contact receiving slots  126  of the molded housing halves  10  and  20  for guiding or retaining the contact strips  30 . Each end of the elongated element  80  defines an opening  801  cutting through in the vertical direction so that two parallel branch boards  85  are formed. The branch boards  85  are flexible and each board defines a circular hole  803  near the opposite ends.  
         [0036]      FIG. 6  is a perspective view of the latch/release arm  50 . The latch/release arm  50  includes a base board  52  perpendicular to the width direction, a pair of pivot shafts  56  projecting along the width direction from the base board  52 , a flexible spring-finger  54  extending horizontally from the base board  52 , a tab  55  connected to a bottom portion of the base board  52 , an upper latch arm  58  extending upwardly from the base board  52 , a latch-arm kicker spring  59  extending downwardly from a lower end of the upper latch arm  58 . The tab  55  defines a surface or edge  551  facing downwardly. The upper latch arm  58  protrudes an inward nose  581  for mating into a cutout  40  defined in the inserted PCB  400 . The latch-arm kicker spring  59  is a cantilever structure and forms an outwardly slanted end  591 .  
         [0037]     Referring to  FIG. 7 , the molded center bar  70  is shown as an elongated component. The molded center bar  70  forms a bottom wall  72  and a pair of lateral walls  74  connected to opposite sides of the bottom wall  72 , and thus a through U-shaped slot  76  is defined. The center bar  70  also has on both sides thereof a number of fingers  721  and slots  723  respectively corresponding to the slots  126  and the fingers  127  of the molded housing halves  10  and  20 .  
         [0038]     Referring to  FIG. 8 , the contact strips  30  are shown. Each of the contacts  31  forms an intermediate securing portion  315  for securing the contact  50  to the molded housing halves  10 , a terminal portion  313  extending downwardly from the securing portion  315  for press fitting into through holes defined in a mother PCB, a slanted cantilever  317  extending upwardly from the securing portion  315  and a contacting portion  319  formed near an end of the cantilever  317 .  
         [0039]     The pieces of epoxy beads  90  are made of a kind of epoxy-ester that can be purchased as commercial item.  
         [0040]     Referring to  FIGS. 1 and 9 - 14 , in process of assembly of the connector  100 , the two contact strips  30  are firstly respectively disposed into the contact receiving slots  126  of the molded housing halves  10  and  20 , with the slanted cantilever  317  leaning away from the sidewall  12 . Secondly, two pieces of epoxy beads  90  are respectively applied across the entire rows of the contacts  30 . Thirdly, the center bar  70  is jogged onto the epoxy bead  90  of one subassembly from the second step and the center bar  70  is so dimensioned that it snugly fits between the resting tabs  124  of the molded housing half  10 , 20 . Fourthly, the latch/release arms  50  are oriented with respect to ends of the carriage  80  and then pushed into the openings  801  of the carriage  80  so that the pivot shafts  56  snap into the circular holes  803  of the carriage  80  and the latch/release arms  50  are rotatably assembled to the carriage  80 . Fifthly, the carriage subassembly from the fourth step is placed into the U-shaped slot  76  of the center bar  70  with two opposite ends of the carriage  80  disposed beyond the corresponding ends of the center bar. At this moment, the guiding towers  824  of the carriage  80  respectively engage into the guiding grooves  122  and the tabs  55  are kept aligned with the guiding grooves  122  by the resting tabs  124 . Sixthly, the subassembly from the second step is combined with the subassembly from the fifthly step so that the epoxy beads  90  are compressed and distributed between the strips of contacts  30  and plastic components of the housing. During this step, the guiding posts  142  and the guiding holes  122  of the housing halves  10  and  20  provide preliminary alignment. Proper alignment is accomplished by the fingers  721  of the center bar  70  interlacing with the fingers  127  of the housing halves  10  and  20 . Finally, the whole assembly is subject to heat, the temperature and length of the heat cycle depending on the selection of epoxy properties, and then is cooled down, resulting in the two housing halves  10  and  20  and the center bar  70  united or bonded together by the epoxy beads  90 .  
         [0041]     It should be mentioned that before the card edge connector  100  is mounted onto the mother PCB, the carriage subassembly is pushed upwardly till the guiding towers  824  abut the stop surfaces  128  of the housing halves  10  and  20 . When the carriage subassembly is moving upwardly in the housing due to engagement between the nose  581  of latch arm  58  and the cut-out  40  of the daughter card  400 , the tab  55  rises up to such a level that it is cleared of, and therefore is slidable over, the resting tab  124 , aided by the end  591  of the latch-arm kicker spring  59  resiliently pressed against the slope cam surfaces  148  of the cam protrusions  144 . When the carriage subassembly is stopped by the stop surfaces  128  of the housing halves  10 , 20 , the tabs  55  of the latch/release arms  50  sliding over the resting tab  124  enables the latch/release arms  50  to rotate outwardly approximately  10  degrees by forces from the cam faces  144  applying to the ends  591  of the latch-arm kicker springs  59 . When the carriage assembly is kept in its uppermost position, the contact portions  319  of the contacts  31  rest on the carriage  80  so that they are protected from corrosive effect from the environment, and a card slot defined by the two housing halves  10  and  20  for the daughter card  400  to be inserted into is shuttered and protected from dust intrusion by the carriage  80 . Also, in such arrangement, relative sliding movement of the contact portions  319  of the contacts  31  in the slots  822  of the carriage  80  provides a mechanism so that the contact portions  319  can be properly lubricated by the carriage  80  made of an adequately selected material known to person in this art.  
         [0042]     Referring to  FIG. 15-17 , the operation of the preset invention will be described. Initially, the leading edge of the daughter PCB  400  is inserted. The PCB  400  first comes into contact with the flexible spring-fingers  54  of the latch/release arms  50 . As these spring fingers  54  of the latch arms  50  are momentarily compressed by the PCB  400 , they absorb shock as the latch arms rotate to vertical. The base boards  52  extends below ends of the spring-fingers  54  and fits in the openings  801  of the carriages  80  for guiding the rotations of the latch/release arms  50  and protecting the spring-fingers  54  from excessively deformed when being abruptly pressed by the inserted PCB  400 . Cut-outs  40  in the PCB  400  provide pockets for the protruding nose  581  of each latch/release arm  50 . As the latch/release arms  50  are moving toward their vertical positions, the latch-arm kicker springs  59  are momentarily compressed against end walls  14  of the connector housing. When the latch/release arms  50  further moves downward to such a position where the surfaces  551  of each latch arm  50  is clear of the resting surfaces  125  of the resting tabs  124  of the housing and are free to move downwardly into the connector  100 , the carriage  100  will be carried to move down together therewith. As the carriage  80  travels downward, the contacts  31  drop off from the carriage  80  and onto the pads of the PCB  400 . Full contact normal force occurs at this moment along a substantial length of the PCB board&#39;s pads.  
         [0043]     Removal of the PCB  400  is the reverse of the above. When the carriage subassembly is pulled up by the daughter board  400  far enough to deflect the contacts  31  back out, the latch/release arms  50  are cleared to rotate back out to 10 degrees off of vertical, thereby releasing the PCB  400  from the connector  100  and preparing it for the next insertion of a PCB  400 .  
         [0044]     By eliminating the abrupt transition that typically occurs between the connector  100  and the PCB  400  during mating and unmating, the invention extends the durability and reliability of the PCB  400  and the connector  400 , improves signal integrity by reducing the physical length of contact (as a long lead-in ramp on the contacts is no longer required), reduces the force transmitted to the backplane board during insertion of the card-edge PCB  400  by approximately half, and provides corrosion/contamination protection to the contact interfaces whether or not a PCB is installed.  
         [0045]     It is to be understood, however, that even though numerous, characteristics and advantages of the present invention have been set fourth in the foregoing description, together with details of the structure and function of the invention, the disclosed is illustrative only, and changes may be made in detail, especially in matters of number, shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.