Abstract:
A socket connector ( 5 ) includes a base ( 6 ), a cover ( 7 ) slidably assembled onto the base and capable being moved with respect to the base along a first direction, an actuator ( 8 ) for actuating the cover to slide on the base between a contact insert position and a second engagement position, and guiding and latching arrangement ( 621 ) arranged between the base and the cover and adjacent to the actuator so as to balance a movement of the cover along a second direction substantially traverse to the first direction.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the invention  
         [0002]     The present invention relates to an electrical connector, and more particularly to a ZIF (Zero Insertion Force) socket connector for connecting a central processing unit (CPU) of a computer system to a printed circuit board (PCB).  
         [0003]     2. Description of Related Art  
         [0004]     ZIF sockets are known in the art for connecting Integrated Circuit (IC) packages to printed circuit boards. U.S. Pat. Nos. 6,338,640, 6,431,900, 6,579,112, 6,254,415 disclose some ZIF socket connectors. Referring to  FIG. 6 , one example of such conventional connectors comprises a base  2 , a cover  3 , and an actuator  41 . The cover  3  is movably mounted on an upper surface of the base  2 . The actuator  41  is in form of a cam comprising at least two cylindrical portions, central axes of which are offset from each other. One of the cylindrical portions interferes with the base  2  and another interferes with the cover  3 . When the actuator  41  is rotated, the cam axe moves to push or pull the cover  3  to slide with respect to the base  2 , along an anticipative front-to-back direction, that is between a contact insert position and a contact engagement position. When the actuator  41  is rotated to drive the cover  3  to slide along the front-to-back direction, an inevitable force along a left-to-right direction may exert on the cover  3 , which causes a sideways movement of the cover  3  with respect to the base  2 . When this happens, the cover  3  may slide improperly or even fail to slide.  
         [0005]     To overcome above-motioned problems, an improved socket connector is desired.  
       SUMMARY OF THE INVENTION  
       [0006]     An object of the present invention, therefore, is to provide a socket connector with anti-rotation design for preventing a cover thereof from sideways moving with respect to a base thereof.  
         [0007]     Accordingly, to achieve the above object, a socket connector for connecting a central processing unit (CPU) to a printed circuit board of the present invention comprises a base arranged in a first plane defined by a lengthwise and a lateral direction and defining a plurality of passageways receiving a plurality of terminals extending from the printed circuit board, a cover arranged in a second plane and slidably mounted on the base, and defining a plurality of channels in a one-to-one corresponding relationship with the passageways of the base for receiving a plurality of contacts of the CPU, block means formed on one of the base and the cover and protruding out of the corresponding one of the first and the second planes for preventing the cover from sideways moving in said lateral direction, a receiving hole defined in the other one of the base and the cover for receiving the block means with a certain movement space remained for the block means sliding in said lengthwise direction, and an actuator for driving the cover to slide on the base between a contact insert position and a second engagement position.  
         [0008]     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  
       [0009]      FIG. 1  is a simplified exploded view from a top aspect of view of a socket connector in accordance with a first embodiment of the present invention;  
         [0010]      FIG. 2  is a simplified exploded view from a bottom aspect of view of the socket connector in accordance with the first embodiment of the present invention;  
         [0011]      FIG. 3  is an assembled perspective view of the socket connector of  FIG. 1  in an initial contact insert position;  
         [0012]      FIG. 4  is an assembled perspective view of the socket connector of  FIG. 1  in a final contact engagement position;  
         [0013]      FIG. 5  is a simplified exploded view from a bottom aspect of view of the socket connector in accordance with a second embodiment of the present invention; and  
         [0014]      FIG. 6  is an exploded view of a conventional socket connector. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0015]     Reference will now be made to the drawing figures to describe the present invention in detail.  
         [0016]     Referring to  FIGS. 1-5 , a socket connector  5  in accordance with a first embodiment of the present invention is used for connecting a chip module (not shown) to a printed circuit board (not shown) and comprises a base  6 , a cover  7  slidably engaged on the base  6  in a front-to-rear direction, a plurality of contacts (not shown) received in the base  6 , an actuator  8  in form of a cam and a washer  9  for fixing the actuator  8 .  
         [0017]     The base  6  comprises an insulative mainbody  61  in the shape of a square, an insulative front portion  62  in front of the mainbody  61  and a T-shaped metallic base plate  63 . The mainbody  61  defines a first central opening  610  in a middle region thereof and a plurality of passageways  611  in the periphery of the central opening  610  and extending vertically through the mainbody  61 . Each passageway  611  receives a terminal (not shown) therein. A pair of protrusions  613  extend from each side edge  612  of the mainbody  61 . The front portion  62  comprises an upper surface (not labeled) for mating with the cover  7  and a bottom surface (not labeled) for mating with the printed circuit board. The bottom surface defines a T-shaped recess  626  for receiving the base plate  63  and a base through hole  620  for engaging with actuator  8 . A pair of blocks  621  upwardly protrude from the upper surface of the front portion  62  and are respectively arranged on opposite lateral sides of the base through hole  620 . Each block  621  comprises a guiding member  622  and a latch member  623  arranged adjacent to an outer face of the guiding member  622 . The pair of guiding members  622  have opposite inner faces for preventing a sideways movement along the lateral direction between the cover  7  and the base  6  by abutting against the cover  7 . A groove  624  is defined between each guiding member  622  and a corresponding latch member  623  in order to enable the latch member  623  to resiliently move with respect to the guiding member  622 . Each latch member  623  forms a fastening end  625  in form of a hook on a top thereof for securely engaging with the cover  7 . The base plate  63  defines a plate through hole  630  corresponding to the base through hole  620 .  
         [0018]     The cover  7  comprises an insulative body portion  71  in the shape of a square, an insulative header portion  72  in front of the body portion  71 , a metallic top cover plate  73  and a metallic bottom cover plate  74 . The body portion  71  defines a second central opening  710  and a plurality of channels  711  provided in a one-to-one corresponding relationship with the passageways  611  of the underlying base  2 , and comprises a pair of lateral flanges  712  depending down vertically on two sides thereof. Each flange  712  defines a pair of fixing slots  713  in an inner wall thereof for receiving corresponding protrusions  613 , respectively, each leaving a small distance for the protrusions  613  to slide therein along a lengthwise direction, and a recess  714  for facilely operating the chip module. The header portion  72  has a top and a bottom faces  722 ,  723  and defines a rectangular cover through hole  720  and a pair of rectangular receiving holes  721  at opposite sides of the cover through hole  720  for receiving the pair of blocks  621 , respectively. The cover through hole  720  and the receiving holes  721  are substantially in a line. The top cover plate  73  defines a first central hole  730  corresponding to the base through hole  620  for engaging with the actuator  8 , and a pair of first side holes  731 . The bottom cover plate  74  defines a second central hole  740  and a pair of second side holes  741 . The first central hole  730  is corresponding to the cover through hole  720  and the second central hole  740 . The first side holes  731  are corresponding to the receiving holes  721  and the second side holes  741 . Lateral dimensions of the first side hole  731 , the receiving hole  721  and the second side hole  741  are equal to that of each block  621 , thereby providing a fitable engagement therebetween in the lateral direction in order to prevent the cover  7  lateral moving with respect to the base  6 . Longitudinal dimensions of the first side hole  731 , the receiving hole  721  and the second side hole  741  are a little larger than that of each block  621 , which is to provide a movement space for the block  621  in the lengthwise direction. A pair of stoppers  742  are formed on opposite sides of the second central hole  740  of the bottom cover plate  74  to stop the actuator  8 .  
         [0019]     The actuator  8  successively comprises a first, a second, a third and a fourth cylindrical posts  81 ,  82 ,  83  and  84  formed one on the other. The cylindrical posts progressively decrease in diameter from top to bottom. The first post  81 , the second post  82  and the third post  83  are respectively received in the first central hole  730 , the cover through hole  720  and the second central hole  740 , and the base through hole  620  and the plate hole  630 . The fourth post  84  is for fitting with the washer  9 . A diameter of the first post  81  is equal to that of the first central hole  730  and a diameter of the third post  83  is equal to that of the base through hole  620 . The second post  82  has a diameter equal to lateral lengths of the cover through hole  720  and the receiving hole  740  but shorter than longitudinal lengths thereof, which remains a movement space in the lateral direction to the second post  82  but restrains the movement in the lengthwise direction in the cover through hole  720  and the second central hole  740 . The second cylindrical portion  82  forms a bulge  85  from a circumferential periphery thereof. Central axes of the first, the third and the fourth cylindrical portions  81 ,  83  and  84  are in-line, but the second cylindrical portion  82  is offset, which forms a eccentricity design.  
         [0020]     In assembly, the top cover plate  73 , the bottom cover plate  74  and the base plate  63  are respectively insert-molded or mechanical pressed onto the top face  722  and the bottom face  723  of the header portion  72  of the cover  7  and the T-shaped recess  626  of the base  6 . The top cover plate  73  is assembled to prevent the cover  7  from engaging directly with the actuator  8 , which may result in abrasion of the cover  7 . The cover  7  is mounted onto the base  6  with the protrusions  613  of the base  6  engaging with the fixing slots  713  of the cover  7 , the lateral flanges  712  of the body portion  71  respectively fastening two opposite sides of the base  6 , and the pair of blocks  621  respectively received in the corresponding first side hole  731 , second side hole  741  and receiving hole  721 . The fastening ends  625  of the blocks  621  hook outer edges of the first side holes  731  of the top cover plate  73  whereby the blocks  621  are fixed.  
         [0021]     The actuator  8  is sequentially extended through the first central hole  730 , the cover through hole  720 , the second central hole  740 , the base through hole  620  and the plate through hole  630 , and then is riveted with the washer  9  to be secured in the socket connector  5 . The bulge  85  on the actuator  8  is extended into a space between the header portion  72  and the bottom cover plate  74  and can rotate in said space and be restricted by the stoppers  742 . Widths of the blocks  621  being smaller than those of the first and second holes  731 ,  741  and the receiving holes  721 , and the eccentricity design of the actuator  8  corporately make the actuator  8  drive the cover  7  to slide on the base  6  in the lengthwise direction between a first contact insert position at which contacts of the CPU are inserted into the channels  711  of the cover  7  and the passageways  611  of the base with Zero Insertion Force and a second engagement position at which then contacts of the CPU in the passageways  611  engage the terminals in the passageways  611  of base  6 .  
         [0022]     According to the above-mentioned configuration, when the actuator  8  drives the cover  7  to slide on the base  6  between the contact insert position and the contact engagement position, the guiding members  622  of the base  6  and the flanges  712  of the cover  7  corporately restrict sideways movement of the cover  7  with respect to the base  6 , wherein the guiding members  622  are stronger, more tightened and more effective to resist against said sideways movement. Thereby, with such a design, the possible sideways rotation movement of the cover  7  is avoided or at least minimized, that ensures proper and efficient connection between the contacts and the terminals.  
         [0023]     In this preferred embodiment, the bottom cover plate  74  can be limited. Without the bottom cover plate  74 , the stoppers  742  can be formed at a suitable position on the top cover plate  73  to restrict the rotation of the actuator  8 . Accompanyingly, the bulge  85  is formed on the first cylindrical post  81  instead of the second cylindrical post  82 .  
         [0024]     Referring to  FIG. 5 , a socket connector  5 ′ in accordance with a second embodiment of the present invention comprises a base  6 ′, a cover  7 ′ and an actuator  8 ′. The cover  7 ′ comprises a pair of blocks  621  ′ extending from a bottom face thereof which has the same configuration as the one designated  621  in  FIG. 1 . The base  6 ′ defines a pair of receiving holes  721 ′. A step member  723 ′ inwardly extends from an outer edge of each receiving hole  721 ′ for engaging with a corresponding fastening end  625 ′ of the block  621 ′. Concrete structure and assembly process of the socket connector  5 ′ can refer to the first embodiment.  
         [0025]     It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of 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.