Abstract:
Disclosed is an LGA socket ( 1 ) including a socket body ( 10 ) having a number of terminals ( 11 ) embedded therein. A stiffener ( 12 ) is bottomed to the socket body. A load plate ( 14 ) and a load lever ( 15 ) are pivotally assembled to two opposite ends of the stiffener. At least one of the stiffener and the load plate is formed to have a lateral-opened hollow frame by stamp of an elongated strip of metal.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention generally relates to electrical connectors and, more particularly, to a land grid array (LGA) socket to provide electrical connection between an LGA package and an electrical substrate, such as a printed circuit board (PCB).  
         [0003]     2. Background of the Invention  
         [0004]     Various types of conventional electrical connectors for attaching IC packages are known. Each of the IC packages has a large number of contacts arranged in an array of rows and columns. The IC packages are generally classified as pin grid array (PGA) packages, ball grid array (BGA) packages, or land grid array (LGA) packages, depending on shapes of an electric contact portion of the contacts.  
         [0005]     Because of the widely used LGA packages, many LGA sockets have been developed to electrically connect the contacts of the IC packages with terminals of the corresponding LGA sockets. A typical LGA socket includes a socket body, in a rectangular shape, and a plurality of electrical terminals assembled on the socket body. A set of retention members is provided to retain the IC package in the socket body so as to establish electrical connection therebetween. To comply with the rectangular socket body, some of the retention members, such as a cover member or a reinforcing plate, are required to have a generally rectangular hollow frame. The hollow frame is provided with a large central rectangular through-hole, which is adapted for receiving the socket body therein.  
         [0006]     However, in manufacturing, an abundant of material may be often removed and thereby wasted, because each of these rectangular members is formed by punching of a sheet of metal into the central through-hole frame. This will directly result in much more additional costs to the overall manufacturing of the LGA socket.  
         [0007]     In view of the above, it is desired to provide a new LGA socket which overcomes the above-mentioned disadvantages.  
       SUMMARY OF THE INVENTION  
       [0008]     LGA sockets according to preferred embodiments of the present invention are provided with lateral-opened hollow frames for some rectangular frame-like members of the LGA sockets, especially a metallic load plate or a stiffener.  
         [0009]     The lateral-opened hollow frame is preferably formed by stamping an elongated strip of metal, and bending into the lateral-opened hollow frame. Alternatively, a plurality of sidewalls may be configured to form the lateral-opened hollow frame.  
         [0010]     Due to such formation of the frame-like members, no material is removed and wasted, as opposed to the conventional formation of the load plate and the stiffener. Thus, additional cost associated with the LGA sockets is increasingly reduced.  
         [0011]     Other features and advantages of the present invention will become more apparent to those skilled in the art upon examination of the following drawings and detailed description of preferred embodiments, in which: 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]      FIG. 1  is an exploded, isometric view of an LGA socket in accordance with a preferred embodiment of the present invention;  
         [0013]      FIG. 2  is an assembled, isometric view of a part of the LGA socket of  FIG. 1 , not showing a socket body therein;  
         [0014]      FIG. 3  is an isometric view of a load plate of the LGA socket of  FIG. 1 ;  
         [0015]      FIG. 4  is an isometric view of a stiffener of the LGA socket of  FIG. 1 ; and  
         [0016]      FIG. 5  is an assembled, isometric view of the LGA socket of  FIG. 1 , but showing the socket body therein.  
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0017]     Reference will now be made to describe preferred embodiments of the present invention in detail.  
         [0018]     Referring to FIGS.  1  to  5 , an LGA socket  1  according to a preferred embodiment of the present invention is shown to establish electrical connection between an LGA package (not shown) and a circuit substrate (not shown) mounting on the LGA socket  1 .  
         [0019]     The socket  1  includes a simplified socket body  10  embedded with a plurality of terminals  11 . A stiffener  12  is attached to a bottom surface of the socket body  10 . A load plate  14  is pivotally mounted on a first end of the stiffener  12 . A load lever  15  is pivotally supported on an opposite second end of the stiffener  12 . The load lever  15  engages with a free end of the load plate  14  to lock the load plate  14  in a closed position, where the load plate  14  presses the LGA package toward the socket body  10  to bring the LGA package into contact with the terminals  11  of the socket  1 . Thus, through the socket  1 , electrical connection is established between the IC package and the circuit substrate via the LGA socket  1 .  
         [0020]     The socket body  10  is made of insulative material, and shaped in the form of a generally rectangular frame. An upper section of the socket body  10  has an receiving region  101  defined between a front part  102  and a rear part  103  of the socket body  10 . The receiving region  101  includes a plurality of passageways (not shown) arranged in columns and rows, for receiving the respective terminals  11  therein. It should be noted that, while the socket body  10  similar to the conventional socket body known in the art is preferred, but any socket body of somewhat different shape may be also employed.  
         [0021]     Each of the terminals  11  generally includes a base section  110  secured in the corresponding passageway, an upwardly extending section  112  for electrically mating with a corresponding conductive pad of the LGA package, and a downwardly extending section  114  for electrical connection to a corresponding circuit pad of the substrate.  
         [0022]     The stiffener  12  is substantially of a rectangular frame with thereof an off-cut or separated sidewall  1201  adjacent the front part  102  of the socket body  10 . Preferably, the stiffener  12  is formed by stamping an elongated strip of metal, and then bending the strip into a lateral-opened hollow frame. Alternatively, in other embodiments, a plurality of sidewalls may be employed to form the lateral-opened frame by any other suitable machining means, such as welding or fastening means. Accordingly, the stiffener  12  so formed has a central through-hole  121  with a lateral off-cut opening  1200  defined by the sidewall  1201  thereof, without generation of wasted material. The central through-hole  121  is surrounded by the first sidewall  1201 , a second sidewall  1202 , a third sidewall  1203 , a fourth sidewall  1204 . Preferably, the sidewalls  1202 ,  1203 ,  1204  are continuous, and curved downwards and bent inwards to cooperatively form a common supporting surface  124  to receive the socket body  10  therein. Preferably, a part of the supporting surface  124  adjacent the third sidewall  1203  is slightly wider than that of the other sidewalls  1202 ,  1204 , so that the socket body  10  assembled therein can be mostly secured by that part of supporting surface  124 . Opposite ends of the lateral opening  1200  of the first sidewall  1201  are respectively provided with a pair of retaining elements  128 ,  129 , for cooperatively supporting at least part of the lever  15  inserted therefrom. The first element  128  is not structurally the same as the second element  129 , but in reversed relationship with the second retaining element  129 . That is, the downward-facing surface of the first retaining element  128  is concave and the upward-facing surface of the reversed retaining element  129  is convex, so as to prevent the interlocking portion  153  of the lever  15  to remove therefrom when the lever  15  is supported by the pair of retaining elements  128 ,  129 . The second sidewall  1202  has an interlocking protrusion  127 , for engaging with the actuating portion  151  of the lever  15 . In additional, the third sidewall  1203  has a pair of spaced mounting slots  126 , for engaging with the pair of bearing tongues  144  of the load plate  14 , respectively.  
         [0023]     The load lever  15  is generally formed by bending a single metallic wire and includes a pair of spaced rotary shafts  152 , which are partially supported by portions of the first sidewall  1201 . An interlocking portion  153  is disposed between the rotary shafts  152 , and is displaced relative to the rotary shafts  152 , for locking the load plate  14  in the closed position. An actuating portion  151  for rotating the rotary shafts  152  is bent to be at a right angle with respect to the rotary shafts  152 . A distal end of the actuating portion  151  is formed with a finger-like shape in order to form a handle  154  for ease of actuation.  
         [0024]     The load plate  14  is also configured to have a generally rectangular hollow frame with a lateral off-cut opening  140  defined by a separated first sidewall  141  thereof. The formation of the load plate  14  is preferably similar to that of the stiffener  12 , but the opening  140  is facing in opposed relationship with the opening  1200  of the stiffener  12 . Therefore, no additional material is wasted during manufacturing of the load plate  14 .  
         [0025]     The first sidewall  141  has a curved surface shaped to engage with the third sidewall  1203  of the stiffener  12 , in order to be pivotally movable between an opened position (to be hereinafter described) and the closed position. A pair of spaced bearing tongues  144  projects from portions of the first sidewall  141  adjacent opposite ends of the opening  140  respectively, and is further curved upwards so as to engage with the corresponding mounting slots  126  of the stiffener  12 . A second sidewall  142  opposite the first sidewall  141  is formed with a downwardly curved locking section  143 , for engaging with the interlocking portion  153  of the lever  15 . Additionally, side edges  145  between the first sidewall  141  and the second sidewall  142  are bent slightly downward in the middle portions thereof, in order to engage with the upper surface of the LGA package inserted into the socket body  10 .  
         [0026]     Referring to  FIGS. 1 and 5 , in assembly, the bearing tongues  144  of the load plate  14  are inserted to engage with the mounting slots  126  of the stiffener  12  respectively, so that the load plate  14  is pivotally movable between the opened position and the closed position by engagement of the tongues  144  and the slots  126 . The lever  15  is assembled into the first sidewall  1201  of the stiffener  12  by the pair of retaining elements  128 ,  129  that cooperatively support part of the lever  15 . Then, the socket body  10  embedded with terminals  11  is loaded into the stiffener  12 , and retained by the supporting surface  124  around the central through hole  121  of the stiffener  12 . In that position, a receptacle between the first sidewall  1201  and the front part edge of the socket body  10  is thereby remained to receive the interlocking portion  153  of the lever  15 . It should be noted that, while the above assembly illustrated is preferred, any other possible assembly may also be employed herein.  
         [0027]     In operation, the actuating portion  151  of the load lever  15  is released so as to enable the lever interlocking portion  153  to be disengaged from the locking portion  143  of the load plate  14 . When the load plate  14  is placed in an opened position, the LGA package is loaded to be resided within the receiving region  101  of the socket body  10 . The load plate  14  is pivoted to the closed position, and the actuating portion  151  is driven to lower the interlocking portion  153  so as to permit the load plate  14  to press the LGA package toward the socket body  10  to cause electrical connection between pads of the IC package and terminals  11  of the socket body  10 .  
         [0028]     While the present invention has been described with reference to preferred embodiments, the description of the invention is illustrative and is not to be construed as limiting the invention. Various of modifications to the present invention can be made to preferred embodiments by those skilled in the art without departing from the true spirit and scope of the invention as defined by the appended claims.