Patent Publication Number: US-7588441-B2

Title: Electrical connector with improved housing structure

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an electrical connector, and more particularly to an electrical connector with an improved housing which could reduce warpage of the housing. 
     2. Description of the Prior Art 
     With the advent of the electronic age, electronic products have been more and more used in the production and life, and the request of the quality and other aspects thereof is continue to raise. Among many electronic products, computer should be said to be applied considerable and the replacement, also could be said to be advancing with the times, the electrical connector disposed in the computer used to electrically connect an IC chip and a printed circuit board are also replacement constantly. The electrical connector comprises an insulative housing formed with a plurality of contact receiving passageways and a plurality of contacts received in the contact receiving passageways. Recently, the insulative housing of the electrical connector are manufactured more thinner and the number of the contact receiving passageways aligned thereon is are more and more, so it is difficult to control the flatness of the insulative housing. In additional, some of the insulative housings have different structure to adapt the various structures of the contacts, thus will make the insulative housing warpage after the insulative housing is molded. Hence, a new design which can improve the warpage of the insulative housing is required. 
     SUMMARY OF THE INVENTION 
     According, one object of the present invention is to provide an electrical connector with an improved housing to reduce the warpage of the housing for well establishing an electrical connection between an IC chip and a printed circuit board. 
     In order to achieve the object set forth, an electrical connector comprises an insulative housing having a plurality of contact receiving passageways and a plurality of contacts received in the contact receiving passageways of the housing. Each of the contacts includes a main body and a spring contact arm extending upwardly from the main body. The contacts disposed in the housing are divided into a first group in a first area and a second group in a second area of the housing. The spring contact arms of the first and second group extend in different directions and opposite to each other. The insulative housing defines a plurality of recesses between the first area and second area. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view of the insulative housing with contacts of the present invention; 
         FIG. 2  is an enlarged view of circle A of  FIG. 1 ; 
         FIG. 3  is another schematic view of  FIG. 1  from bottom end; and 
         FIG. 4  is a perspective view of the contact of the present invention. 
     
    
    
     DESCRIPTION OF PREFERRED EMBODIMENT OF THE INVENTION 
     Reference will now be made to the drawings to describe the present invention in detail. 
     Referring to  FIG. 1  to  FIG. 3 , an electrical connector is used to electrically connect an IC chip (not shown) and a printed circuit board (not shown). The electrical connector comprise an insulative housing  2 , a plurality of contacts  3  received in the insulative housing  2 , a metal stiffener (not shown) partially surrounding the insulative housing  2 , a metal cover (not shown) and a lever (not shown) respectively pivotally mounted to and received in the opposite ends of the metal stiffener. 
     The insulative housing  2  is substantially rectangular and comprises a planar base (not labeled) and surrounding walls (not labeled) extending upwardly from four sides of the base. The base and the surrounding walls together define a receiving space to receive the IC chip. The base comprises a top surface served as a mating surface  201  for arranging the IC chip thereon and a bottom surface served as a mounting surface  202  attached to a printed circuit board. The base is divided into a first contact area  203 , a second contact area  204  and a partitional section  205  arranged between the first and the second contact area  203 ,  204 . The first and second contact area  203 ,  204  each defines a plurality of contact receiving passageways  206  penetrating the mating surface  201  and the mounting surface  202  for receiving the contacts  3 . Each of the passageways  206  includes an upper space  2060  extending to the mating surface  201  and a lower space  2061  extending to the mounting surface  202  for receiving different part of the contact  3 . The lower space  2061  has a pair of slits  2062  at outer side of the upper space  2060  thereby the width of the lower space  2061  is larger than the upper space  2060 . The partitional section  205  defines a plurality of recesses  2050  open to the mating surface  201 . The recesses  2050  are aligned in one line and sealed at the mounting surface  202  of the insulative housing  2 . The recesses  2050  are perfectly defined in the same shape and size so as to manufacture easier. In the present embodiment, the recesses  2050  are all rectangular shape, however, it also could form a circle shape and other shape. The recesses  2050  are disposed around four contact receiving passageways  206  between the first contact area  203  and the second contact area  204  for having a bigger space to dispose therein. The mounting surface  202  of the insulative housing  2  has a number of standoffs (not shown) used to avoid the solder balls over melting when the electrical connector welds on the printed circuit board. 
     Referring to  FIG. 4 , the contact  3  comprises a main body  30  received in the contact receiving passageway  206 , a pair of the spring contact arms  301  extending upwardly from top of the main body  30  toward the mating surface  201 , a pair of spring solder arms  302  extending downwardly from bottom of the main body  30  toward the mounting surface  202 , and a pair of tabs  303  formed on two sides of the main body  30  and extending downwardly at opposite sides of the spring solder arm  302 . The spring contact arms  301  and the spring solder arms  302  are oriented in the same direction of the main body  30 . 
     After assembling, the pair of spring contact arm  301  are received in the upper space  2060 , the main body  30  and the pair of spring solder arms  302  are received in the lower space  2061 , and the pair of tabs  303  are located in the slits  2062 . The contacts  3  disposed in the first contact area  203  is called first group and disposed in the second contact area  204  is called second group. The spring contact arms  301  of the contacts  3  in the first group and second group are opposite to each other. 
     In the present embodiment, because the contact  3  has a pair of downwardly extending tabs  303  result in the upper space  2060  is relatively narrow than the lower space  2061 . This structure will cause the insulative housing  2  generating warp in molding process. In order to reduce the warp, present invention dispose a plurality of recesses  2050  in the mating surface  201  of the partitional section  205 , that can balance flow speed of melting plastic in the process of molding the insulative housing  2 . 
     In assembly the electrical connector, the contacts  3  with solder balls (not shown) in the tail thereon are disposed in the contact receiving passageways  206 . The metal cover and the lever are assembled to two ends of the metal stiffener. Then the electrical connector is positioned to the printed circuit board via the solder balls. Now, the electrical connector is assembled, then putting the IC chip on the insulative housing and close the metal cover and lever, thus stable electrical connection between the IC chip and the printed circuit board is assured. 
     In present embodiment, the insulative housing is divided into two contact areas, it also can be divided into more than this. 
     Although the present invention has been described with reference to particular embodiments, it is not to be construed as being limited thereto. Various alterations and modifications can be made to the embodiments without in any way departing from the scope or spirit of the present invention as defined in the appended claims.