Patent Publication Number: US-2007123094-A1

Title: Electrical connector

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to an electrical connector for electrically connecting a flexible printed circuit to a printed circuit board (PCB).  
      2. Description of Related Art  
      A conventional electrical connector for connecting a flexible printed circuit to a printed circuit board comprises an insulative housing, an actuator pivotably mounted on the housing and a plurality of contacts received in the housing. A flexible printed circuit connecting with the electrical connector defines a plurality of pads on a bottom thereof for connecting with the contacts received in the housing. The actuator can be rotated between an opening position and a closed position. When the actuator is operated in the opening position, the flexible printed circuit is inserted into a receiving cavity of the housing; when the actuator is operated in the closed position, the actuator abuts against the flexible printed circuit tightly for attaining a reliable contact between the pads of the flexible printer circuit and the contacts in the housing. The housing defines a respective receiving slot for receiving a corresponding contact therein. The width of each receiving slot generally defines a minimum value. When the width is defined smaller than the minimum size. The slots of the housing would be hard to mold. The thickness of each contact receiving in the slot of the housing is slightly smaller than the width of the corresponding slot. When the contacts are inserted into the slots of the housing, two sidewalls of each contact abut against the inner wall of each slot of the housing, which can prevent the contacts received in the slots of the housing from shaking too much, when the contacts are pressed downwardly by the actuator, thereby ensuring a reliable electrical connection between the flexible printed circuit and the printed circuit board.  
      However when high frequency signals are transmitted between the flexible printed circuit board and the printed circuit board, the thickness of the contact is generally decreased for decreasing capacitive effect between adjacent contacts. While the width of the slot in the housing attains a minimized size permitted by the molding demand, the thickness of the contact decreased can lead to a wider distance between the outer sidewalls of the contact with the inner wall of the slot in the housing, so that the contacts receiving in the slots shake greater which can bring about the pads of the flexible printed circuit sliding out from the slots of the housing. Hence the flexible printed circuit can not reliably be electrically connected with the printed circuit board.  
      Thereby, an improved electrical connector is required to overcome the disadvantages of the prior art.  
     SUMMARY OF THE INVENTION  
      An object of the present invention is to provide an electrical connector which has reliable structure and can perform securely electrical connection between a flexible printed circuit and a printed circuit board (PCB).  
      In order to achieve above-mentioned objects, an electrical connector in accordance with a preferred embodiment of the present invention includes a housing defining a plurality of receiving slots, a number of electrical contacts received in the housing. Each slot defines four inner walls. The contacts defines a first sidewall and a second sidewall opposite to the first sidewall, a solder portion defined on a distal end thereof, an elastic portion disposed on a top end of the contact and a retention portion connecting the solder and the elastic portion, wherein at least one sidewall of the contact is cleared off with inner walls of the receiving slots, the elastic portion defines a contact portion on an end thereof for connecting with flexible printed circuit, each contact defines at least one protrusion on a sidewall which is clear off the inner wall of the slot.  
      Compared to the conventional technology, the electrical connector in accordance with the invention can decrease thickness of the contacts. When the width of the receiving slots of the housing attains a minimized size, the distance between the first sidewall and the second sidewall is decreased. After the contacts are inserted into the housing, the distance between at least one of sidewalls of the contact and the inner walls of the receiving slot increases. However the projection disposed on the contact can compensate the distance between the contact and the receiving holes of the housing, thus diminishing the swing degree of the contact and preventing the contact portion of the contact from disconnecting with the pads of the flexible circuit board, which can ensure a reliable electrical connection between the electrical connector and the flexible circuit board.  
      Other objects, advantages and novel features of the present 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  
       FIG. 1  is an exploded, isometric view of an electrical connector in accordance with a preferred embodiment of the present invention;  
       FIG. 2  is an assembled view of the electrical connector described in  FIG. 1 ;  
       FIG. 3  is an isometric view a contact of the electrical connector showing in  FIG. 1 ;  
       FIG. 4  is an top plan view of the electrical connector showing in  FIG. 1 ;  
       FIG. 5  is an amplified view of a circle  100  of the  FIG. 4 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      Reference will now be made to the drawing figures to describe the present invention in detail.  
      Referring to  FIGS. 1-5 , an electrical connector  1  in accordance with the preferred embodiment of the present invention comprises a housing  10 , a plurality of electrical contacts  20  received in the housing  10 , an actuator  30  mounted pivotally on the housing  10 , and a cover  40  disposed above the housing  10 .  
      The rectangular housing  10  comprises a first surface  101  and a second surface  102  parallel to the first surface  101 , a first sidewall  103  and a second sidewall  104  perpendicular to the first surface  101 . The first surface  101  defines downwardly a plurality of receiving slots  105  and a securing channel  106 , which do not penetrate through the second surface  102 . The housing  10  further defines a first receiving recess  107  adjacent to the first sidewall  103  in a transverse direction, and a second receiving recess  108  adjacent to the second sidewall  104 . The receiving slots defines a bottom surface  1055 , a first inner surface  1053  and a second inner surface  1054  perpendicular to the first inner surface  1053 , an anchoring projection  109  extending from the first inner surface  1053  toward the second sidewall  104 , and a first engaging slot  110  and a second engaging slot  112  disposed on the second inner surface  1054  and connecting with each other. In addition, the second surface  102  defines inwardly a pair of receiving passageways  115  for receiving the contacts  20  therein.  
      The actuator  30  defines a rectangular base plate  301 . The base plate  301  disposes a retention post  302  and a securing projection  305  on two ends thereof, and a plurality of channels  306  well distributed for preventing actuator  30  from interference with the anchoring projection  109 .  
      The cover  40  comprises a rectangular base portion  401 , a first engaging hook  402  and a second engaging hook  405  disposed on two transverse ends thereof. The base portion  401  defines a pair of solder tails  408  on the longitudinal ends thereof for connecting to the printed circuit board, which can enhance the stability and reliability of the connection between the electrical connector  1  and the printed circuit board.  
      Referring to  FIGS. 3-5 , each contact  20  defines a solder portion  201 , a retention portion  202 , an elastic portion  205 , a first channel  209  disposed in the solder portion  201  and a second channel  210  disposed between the retention portion  202  and the elastic portion  205 . In addition, each contact  20  further defines a first sidewall  207  and a second sidewall  208 . In this embodiment when the contacts  20  are inserted into the housing  10 , each first sidewall  207  abuts against the inner wall of the receiving passageway  115 ; each second sidewall  208  is clear off a wider distance with the inner wall of the receiving passageway  115 . The retention portion  202  extends a first projection  211  and a second projection  212  from the first sidewall  207  toward the second sidewall  208 , which is disposed on upper and lower position of the retention portion  202  respectively and extending beyond the second sidewall  208 . The first projection  211  and the second projection  212  each define an outer surface  2116  parallel to the second sidewall  208 . The retention portion  202  defines an engaging portion  2023  for engaging with the corresponding portion of the receiving passageway  115 . In fact, if each contact  20  in accordance with the invention only defines a projection, namely the first projection  211  or the second projection  212 , the electrical connector  1  can also attains the object of the invention. In addition, when the contacts  20  are inserted into the receiving holes of the housing  10 , if the first sidewall  207  and second sidewall  208  of the contact  20  are both clear off a distance with the inner wall of the receiving passageway  105 , the retention portion  202  can disposed a third projection and a fourth projection on central section thereof, which are disposed on upper and lower position of the retention portion  202  respectively and one projection extending out of the first sidewall  207  and the other projection extending out of the second sidewall  208 . In this state, the objection of the invention can also be attained.  
      In assembly, the contacts  20  are inserted into the receiving passageways  115  of the housing  10  and disposed opposite to each other, wherein the elastic portion  205  partially extends out of the receiving slot  105  of the housing  10 , namely a free end of the elastic portion  205  locating above the bottom surface  1055  of the receiving slot  105 , and the solder portion  201  extends beyond the receiving holes  115  in order to solder to the printed circuit board. And then the actuator  20  is inserted into the housing  10  in a direction parallel to the first surface  101  of the housing  10 . In the state, a lower surface of the anchoring projection  109  abuts against a corresponding surface of the actuator  30 , the retention posts  302  of the actuator  30  are engaged with receiving slots  105  of the housing  10  and the securing projection  305  are received in the second engaging slot  112 . At this time, the actuator  30  mounted on the housing  10  can rotate about the retention posts  302  of the actuator  30 . At last, the cover  40  is mounted on the housing  10 , the base portion  401  engages with the securing channel  106  of the housing  10  and the first hook  402  is inserted into the first receiving recess  107 , and the second hook  405  is inserted into the second receiving recess  108 . Hence the cover  40  is located on the housing  10 .  
      After the electrical connector is assembled, when the actuator is rotated from a horizontal position to an opening position, the flexible printed circuit can be inserted into a space under the bottom surface  1055  of the receiving slot  105 ; at this time, the flexible printed circuit contacts with the contacts  20 . The actuator  30  then is rotated to the horizontal position and presses the flexible printed circuit downwardly, thereby preventing the flexible printed circuit from sliding off. In this process, when the flexible printed circuit presses contacts  20  downwardly, the elastic portion  105  generates an elastic deformation and the contact portion  2054  slides on the surface pad of the flexible printed circuit. Turning to  FIGS. 4-5 , after the contacts  20  are inserted into the housing  10 , the first sidewall  107  abuts against the inner wall of the receiving passageways  115  and the second sidewall  108  is clear off the inner wall with a distance d 1 . Since the contact  20  defines a first projection  211  and a second projection  212 , there is a slight distance d 2  between the outer surface of the contact and the inner wall of the passageways  115 , thereby decreasing shaking of the contacts  20  and preventing the contact portion  115  from sliding out of the flexible printed circuit, which ensures a reliable electrical connection between the electrical connector and the flexible printed circuit.