Abstract:
An electrical connector assembly ( 100 ) includes a first retaining half ( 51 ) securely mounted on a printed substrate, a load plate ( 60 ) pivotally attached to the first retaining half, a second retaining half ( 52 ) opposite and distant to the first retaining half, a lever ( 70 ) pivotally attached to the second retaining half and including a cam portion ( 706 ) capable of pushing down a pressed section ( 610 ) from the clip toward the printed substrate, and a connector ( 30 ) mounted between the first and second retaining halves.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention generally relates to an electrical connector, and more particularly to an electrical connector for removably mounting a chip module to a printed circuit board. The connector is associated with a clip which is individually assembled to a printed substrate by a first device, and pressed to the connector by a lever individually mounted opposite to the clip by a second device. 
     2. Description of Related Art 
     An electrical connector for electrically connecting a chip module to a printed circuit board comprises an insulative housing, a plurality of conductive contacts received in the insulative housing, a stiffener partially surrounding the insulative housing, and a load plate and a lever pivotally mounted to the stiffener. The stiffener is a substantially rectangular frame and comprises a pair of opposite retaining portions to which the load plate and the lever are pivotally mounted and a pair of connecting arms connecting the pair of retaining portions. Usually, the stiffener is stamped from a sheet metal, such as stainless steel which is of high price. In assembly, the insulative housing is connected to the stiffener removably or immovably. Then, the retaining portions are connected to the printed circuit board via retaining means, such as screws, to realize the electrical connection between the contacts and the printed circuit board. Then the chip module is placed on the insulative housing to realize the electrical connection between the chip module and the contacts. Finally, the load plate is placed on the chip module with the lever is rotated until latching with the stiffener. Therefore, the stable electrical connection between the chip module and the printed circuit board is achieved. 
     U.S. Pat. No. 5,722,848 issued to Lai on Mar. 3, 1998 discloses a typical connector socket, and which is generally referred to as ZIF socket. In generally, the socket generally includes a base with a plurality of contacts assembled therein, and a cover moveably attached to the base. A lever along with a cam mechanism is arranged between the base and cover so as to drive the cover from a first position to a second position. When the lever is located in a vertical position, the cover is located at the first position, in which a hole in the cover is completely in align with a corresponding passageway in the base. In this position, a pin leg of a CPU can be inserted from the cover into the passageway without any engagement with the contact. When the CPU is properly seated on the cover, then the lever is moved from the vertical position to a horizontal position, and simultaneously driving the cover from the first position to the second position. During this process, the pin leg of the CPU is then in contact with the contact within the base. 
     U.S. Pat. No. 7,001,197 issued to Shirai on Feb. 21, 2006 discloses another type of connector socket, and which can be generally called LGA socket. As clearly shown in Figures, the socket generally includes a metal stiffener with a housing securely supported therein. Then a metal clip is pivotally assembled to the stiffener. On the other hand, a clip is pivotally assembled to the other side of the stiffener and when the clip is closed to the stiffener, the lever having a cam can lock the clip to a closed position. By this arrangement, if before the clip is closed, and a CPU is seated on the housing, then the clip will tightly press the CPU toward the housing ensuring proper electrical connection therebetween. 
     However, the electrical connector with above structures has at least the shortcomings as follows: The high-cost metal stiffener, or the high-cost stainless steel, causes the cost of the whole electrical connector is increased which is not glad to be seen by manufactures or customers, even consumers. 
     Therefore, it is desired to provide an improved electrical connector to stress the problems mentioned above. 
     BRIEF SUMMARY OF THE INVENTION 
     Accordingly, an object of the present invention is to provide an electrical connector with improved stiffener structures with lower cost. 
     In order to achieve the above-mentioned object, an electrical connector assembly comprises a first retaining half securely mounted on a printed substrate, a load plate pivotally attached to the first retaining half, a second retaining half opposite and distant to the first retaining half, a lever pivotally attached to the second retaining half and including a cam portion capable of pushing down a pressed section from the clip toward the printed substrate, and a connector mounted between the first and second retaining halves. 
     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 
         FIG. 1  is an exploded, perspective view of an electrical connector in accordance with a preferred embodiment of the present invention; 
         FIG. 2  is an assembled, perspective view of the electrical connector in accordance with the preferred embodiment of the present invention; and 
         FIG. 3  a perspective view of a stiffener in accordance with another embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference will now be made to the drawing figures to describe the present invention in detail. 
     Please refer  FIGS. 1-2 , an electrical connector  100  in accordance with a preferred embodiment of the present invention for electrically connecting a chip module (not shown) to a printed circuit board (not shown) comprises an insulative housing  30 , a plurality of contacts (not shown) to be accommodated in the insulative housing  30 , a stiffener  50  partially surrounding the insulative housing  30 , a load plate  60  pivotally mounted to one side of the stiffener  50  for pressing on the chip module, and a lever  70  pivotally mounted to opposite side of the stiffener  50  to latch with the stiffener  50 . 
     The insulative housing  30  is a substantially rectangular board and comprises a flat central accommodating section  304  and four vertical sidewalls  308  extending uprightly from four sides of the accommodating section  304 . The accommodating section  304  comprises a top supporting surface  305  for supporting the chip module, an opposite bottom mounting surface  306  for mounting to the printed circuit board, and a plurality of contact-receiving passages  307  penetrating through the supporting surface  305  and the mounting surface  306 . The contact-receiving passages  307  are arranged in matrix. The contacts are received in the contact-receiving passages  307  with one ends thereof extending beyond the supporting surface  305  for being elastically compressed by conductive pads (not shown) of the chip module, and the other ends thereof equipped with solder balls (not shown) extending beyond the mounting surface  306  for soldering the contacts to corresponding solder points of the printed circuit board. A plurality of protrusions  309  are formed on outer periphery of the sidewalls  308  and adjacent to joint corner of adjacent two sidewalls  308  for interferentially engaging with the stiffener  50  to retain the insulative housing  30  to the stiffener  50 . 
     The stiffener  50  is a frame-shape like and comprises a first retaining half  51  to which the load plate  60  is pivotally mounted, and a second retaining half  52  to which the lever  70  is pivotally mounted. The first retaining half  51  is separate from the second retaining half  52  and the two retaining halves  51 ,  52  together define a receiving space  503  to receive the insulative housing  30 . The first retaining half  51  comprises a flat first base portion  510  and a vertical front wall  511  which defines a pair of retaining recesses  509 . The first base portion  510  is U-shape and comprises a flat first main section  5101  and a pair of first stretching arms  5102  extending rearward from opposite outermost edges of the first main section  5101 . Thus, the first main section  5101  and the pair of first stretching arms  5101  form a half of the receiving space  503  together. An arc-shape latching portion  514  extends upwardly from one side of the first base portion  510  for latching with the lever  70 . The second retaining half  52  comprises a second base portion  520  and a rear wall  521  bending upwardly from the second base portion  520 . The second base portion  520  is also of U-shape and comprises a flat second main section  5201  and a pair of second stretching arms  5202  extending forwardly from outermost edges of the second main section  5201 . Therefore, the second main section  5201  and the second stretching arms  5202  together form the other half of the receiving space  503 . A pair of arc-shape retaining tabs  522  bends upwardly then flatly from the rear wall  521 . A pair of lateral walls  523  extends upwardly from opposite lateral sides of the second main section  5201  with a pair of supporting ribs  524  respectively extending rearward from lower edges thereof. The lever  70  is reliably pivotally mounted to the second retaining half  52  via the retaining tabs  522  and the supporting ribs  524 . Four fastening slots  516  are formed at four corners of the first and second main sections  5101 ,  5201  with four gaskets  90  interferentially received in the fastening slots  516 . 
     The lever  70  is bent from a metal rod and comprises substantially horizontally-extending a retaining portion  702  pivotally mounted to the second retaining half  52  of the stiffener  5  and substantially vertically-extending an operating portion  704  extending perpendicularly from one end of the retaining portion  702 . Further, the retaining portion  702  forms a middle horizontal cam portion  706  parallel to and in front of left and right sections (not labeled) with a pair of arc sections (not labeled) connecting the cam portion  706  and the left and right sections. The cam portion  706  is capable of compressing a part of the load plate  60 . A ring-shape restriction ring  80  is positioned to the left end of the retaining portion  702  for restricting the rotation angle of the lever  70 . 
     The load plate  60  is hollow metal frame and comprises a hollow main body  601  with rectangular shape and a pair of lateral walls  60  bending downwardly from lateral edges of the main body  601 . The front end of the main body  601  is a mounting area and forms a pair of fishhook-shape latching portions  603  bending from a front edge of the main body  601  for latching into the pair of retaining recesses  509 . A flat restriction bar  605  extends forwardly from the front edge of the main body  601  to locate between the pair of latching portions  603  for preventing excessive rotation of the load plate  60 . The rear end of the main body  601  is a pressing area and forms a tongue portion  606  extending rearward from a rear edge of the main body  601  with gradually-decreased width. A flat tip pressed section  610  is formed at a free end of the tongue portion  606  for being pressed by the cam portion  706  of the lever  70  to realize the close position of the load plate  60 . 
     In assembly, the insulative housing  30  with the contacts and the stiffener  50  are interferentially engage with each other via the protrusions  309  latching with the stiffener  50 . Then the contacts are soldered to the printed circuit board. The latching portions  603  of the load plate  60  and the retaining portion  702  are respectively pivotally assembled to the retaining recesses  509  of the first retaining half  51  and the retaining tabs  522  of the second retaining half  52 . Then, the first and second retaining halves  51 ,  52  are fastened to the printed circuit board via fastening means (not shown) to realize the electrical connection between the contacts and the printed circuit board. Then, the chip module is placed on the insulative housing  30  to electrically connect with the contacts and the load plate  60  partially covers the chip module. Then, the lever  70  is rotated until the cam portion  706  thereof presses on the pressed section  610 , and the operating portion  704  is pressed by the latching portion  514  of the first retaining half  514  to realize the stable electrical connection between the chip module and the printed circuit board. 
     Since the stiffener  50  consists of two separate first and second retaining halves  51 ,  52 , that is a first device  51  and a second device  52 , the material connecting the first and second retaining halves  51 ,  52  are omitted. Further, the waste material in stamp process is also decrease. Therefore, the whole cost of the stiffener  50 , even the electrical connector  100  is decreased. 
     Please refer to  FIG. 3 , a second embodiment of the present invention is shown. The structure of the second embodiment is substantially same as that of the electrical connector  100  of the preferred embodiment except that the first and second retaining halves  51 ′,  52 ′ are connected with each other by a pair of plastic connecting members  53 ′. The connecting members  53 ′ can be inserted molded with the first and second retaining halves  51 ,  52 ′, or the connecting members  53 ′ defines receiving spaces to receive corresponding parts of the first and second retaining halves  51 ′  52 ′ to realize the connection between the connecting members  53 ′ and the first and second retaining halves  51 ′,  52 ′. Since the connecting members  53 ′ are made from plastic material which is cheaper compared with the stainless steel, the cost of the electrical connector is also decreased. 
     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.