Patent Publication Number: US-7717729-B2

Title: Electrical socket connector with a load lever having self-biasing device

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an electrical connector assembly for electrically connecting an electronic package such as a land grid array chip to a circuit board, and particularly to an electrical connector assembly with a load lever with self-biasing device. In use, the load lever is automatically biased toward a stiffener ensuring a more reliable engagement with the stiffener when the lever set to a locked position. 
     2. Description of the Related Art 
     Land Grid Array socket, has been widely used in personal computer (PC) system for connecting a CPU onto a printed circuit board (PCB), achieving the signal transferring between the CPU and the PCB, such as disclosed in Patent Issued U.S. Pat. No. 7,001,197 issued to Shirai, which teaches a LGA socket has an insulative housing receiving a plurality of contacts therein. A cover member is pivotally mounted on a first end of the insulative housing or a stiffener. The cover member is pivotal rotated between an open position in which the LGA chip can be disposed and a closed position to press the LGA chip toward the hosing. A load lever is pivotally mounted on a second end of the housing. The load lever has a locking portion for locking the cover in the closed position so as to ensure a reliable interconnection between the LGA chip and the connector. A metallic reinforcing plate is positioned on a bottom surface of the housing. 
     A typical conventional LGA socket  20  is shown in  FIGS. 1 and 2 . The connector comprises an insulative housing  6 , a metal stiffener  7  attached and surrounding the housing  6 , a cover  8  pivotally arranged at one side of the stiffener  7 , a load lever  9  is pivotally arranged on the other side of the stiffener  7 . The housing  6  also defines a plurality of passageways (not show) receiving a plurality of terminals (not show). 
     The stiffener  7  defines a rectangular cavity in the middle for retaining the housing therein, a first hinge  71  and a second hinge  72  are formed on a first end of the stiffener  7 , a connecting end  73  defined on the opposite to the first end, and a locking portion  74  is disposed in a side portion of the stiffener  7  thereof to engage with the arm portion  941  of the load lever  9 . 
     The cover  8  defines a joint portion  81  for connecting with the stiffener  7 , a hook  82  extending from the opposite end of the joint portion  81 . 
     The load lever  9  comprising a first axles portion  91  and a second axles portion  92 , a pressing portion  93  positioned between the first axles portion  91  and the second axles portion  92 , an arm portion  941  generally perpendicularly extending from the second axles portion  92 , and an operating portion extending from the distal end of the arm portion  941 . 
     In use, the pressing portion  93  can be pivoted through rotation to the operating portion  942  between horizontal and vertical position. The connector  20  is firstly in an open state with the cover  8  perpendicular to the housing  6  and the pressing portion  93  of the load lever  9  at a highest position. A LGA chip (not show) is then put into the housing  6 . Then the connector  20  is in a closed state. The cover  8  is rotated down and abutting the LGA chip. Rotate the load lever  9  with the pressing portion  93  pressing on the hook  82  and the arm portion  941  be locked in the locking portion  74  of the stiffener  7 . Thus the LGA chip is stably received in the connector  20 . 
     Because the first axles portion  91  and the second axles portion  92  which received in the first hinge  71  and the second hinge  72  are parallel to the first hinge  71  and the second hinge, gaps are formed between the first axles portion  91  and the first hinge  71 , and between the second axles portion and the second hinge during the connect in an open state and in a closed state, thus it is not compact enough between the load lever  9  and the stiffener. 
     A new electrical connector that overcomes the above-mentioned problem is desired. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a LGA socket with a load lever with self-biasing device. In use, the load lever is automatically biased toward a stiffener ensuring a more reliable engagement. 
     To fulfill the above-mentioned object, land grid array socket accordance with a preferred embodiment of the present invention comprising an insulative housing, a plurality of terminals received in the insulative housing, a metallic stiffener defining an opening for receiving the housing, a cover member and a load lever are respectively and pivotally mounted to the stiffener. The cover and the load lever are pivotal between an open and a closed position. The load lever with self-biasing device comprises a locking portion disposed between a first axles portion and a second axles portion, and an operational arm perpendicularly extending from the end of the second axles portion. When the load lever and the cover are in a closed position, the locking portion of the load lever pressing on one end of the cover. The self-biasing device causes the arm portion of the load lever automatically biasing toward the stiffener ensuring a reliable engagement. 
     Other objects, advantages and novel features of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an assembled, isometric view of a land grid array socket; 
         FIG. 2  is an exploded view of the land grid array socket  FIG. 1 ; 
         FIG. 3  is an exploded view of a land grid array socket in accordance with the preferred embodiment of present invention; 
         FIG. 4  is an assembled view of the land grid array socket of FIG.  3 ; 
         FIG. 5  is a plan, section view of the land grid array socket of  FIG. 3 ; and 
         FIG. 6  is a plan view of the load lever of land grid array socket of  FIG. 3 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 
     Reference will now be made to the drawings to describe the present invention in detail. 
       FIG. 3  shows an exploded, isometric view of a land grid array socket  100  in accordance with a preferred embodiment of the present invention. The LGA socket  100  comprising an insulative housing  2  molded from resin or the like (hereinafter, simply referred to as “housing”). A stiffener  3  defining an opening (not labeled), the housing is positioned in the opening. A cover member  4  is pivotally mounted on a first end  31  of the stiffener  3 . A load lever  5  is pivotally arranged on a second end  32  of the stiffener  3 . 
     The individual elements of the LGA socket  100  will now be described in greater detail. The housing  2  is shaped in the form of a rectangular. A mating surface  22  is defined for mating a LGA package (not show). Conducting region  21  is defined in the center of the mating surface  22  receiving a plurality of terminals (not shown). Peripheral walls  23  extending upwardly from edges of the housing  2 . 
     The stiffener  3  for reinforcing the housing  2  defines a first end  31 , and the first end  31  defining a pair of pivot aperture (not labeled) to engage with the cover  4 . A second end  32  is defined on the opposite of the first end  31 . The second end  32  comprising a first hinge  321  and a second hinge  322  for receiving the load lever  5 . A locking portion  33  is formed in a side portion (not labeled) between the first end  31  and the second end  32 . 
     The cover member  4  is generally rectangular shape defining a generally rectangular frame  43 . A pair of engaging portions  41  is defined in one end of the cover  4  for engaging with the stiffener  3 , a hook  42  extending from the frame  43  on the opposite end to the engaging potions  41 . 
     The load lever  5  is formed by bending a single metallic wire and comprises a first axles portion  51  and a second axles portion  52 . A pressing portion  53  located between the first axles portion  51  and the axles portion  52 . The load lever  5  also has an arm portion  541  generally perpendicularly extending from the second axles portion  52  and an operational portion  542  extending and formed at the distal end of arm portion  541 . The load lever  5  has a self-biasing device at the first axles portion  51  and formed at an angle against to the second axles portion  52 . A protrusion  511  is formed on the first axles portion  51 . 
     Referring to  FIGS. 3-5 , in assembly process, the terminals are pre-loaded within the insulative housing  2 . The insulative housing  2  is then positioned in the opening of the stiffener  3 . The cover  4  is pivotably mounted to the first end  31  of the stiffener  3 . The load lever  5  is pivotably arranged in the second end  32  with the first axles portion  51  and the second axles portion  52  respectively received in the first hinge  321  and the second hinge  322 . The cover  4  and the load lever  5  are firstly in an open state, the LGA package is put onto the mating surface  22  of the housing  2 . When the cover  4  is closed, the pressing portion  53  pressing on the hook  42 , the arm portion  541  is engaged with the locking portion  33  of the stiffener  3 . During rotating the load lever  5  and hooking the arm portion  541  in the locking portion  541 , the protrusion  511  compactly attach on the first hinge  321  of the stiffener, and causing internal-stress between the protrusion  511  and the first hinge  321 . The internal-stress making the arm portion  541  biasing toward the stiffener. Thus, the self-biasing device of the load lever  5  ensuring more reliable engagement between the load lever  5  and the land grid array socket  100 . 
     Because the load lever  5  biasing towards stiffener  3  when the LGA socket is in a closed state, it causing stress between the arm portion  541  and the locking portion  33  to make more compactly connection. 
     Although the present invention has been described with reference to a particular embodiment, it is not to be construed as being limited thereto. Various alterations and modifications can be made to the embodiment without in any way departing from the scope or spirit of the present invention as defined in the appended claims.