Patent Publication Number: US-2010120270-A1

Title: Test socket assembly having stacked insulative boards

Description:
1. FIELD OF THE INVENTION 
     The present invention relates to a test socket, and more particularly to a test socket includes an insulative housing configured by a plurality layers of boards with a plurality of contact terminals arranged therein such that the board can be moved horizontally in accordance with the movement of the contact terminals. 
     2. DESCRIPTION OF RELATED ART 
     Traditional socket assembly, especially testing socket assembly for IC packages, is used for electrically connecting an IC package to a printed circuit board. Such socket assembly usually comprises a unitary base defining a receiving space in a center thereof, two insulative boards mounted within the base under the receiving space, a plurality of contacts retained by the insulative boards and a cover mounted upon the base. The contact has a first contacting portion extending into the receiving space for contacting with an IC package, a middle portion having an arch shape and located in a room defined between the insulative boards in a vertical direction to provide a resilience of the contact and a tail portion for contacting with a printed circuit board. 
     When the contact is pressed by the IC package, the middle portion is curved and moves in a horizontally direction. A distance between adjacent contacts of above socket assembly is designed with a bigger value to prevent short circuit of adjacent contacts, accordingly, this socket assembly may not adapt to miniaturization of sockets and can not provide a high signal transmission speed. 
     Hence, an improved socket assembly is required to overcome the above-mentioned disadvantages of the related art. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a socket assembly having a module configured by a plurality layers of stacked and moveable insulative boards which cooperatively define a plurality of channels therethrough for contacts of the socket assembly. 
     To achieve the aforementioned object, a socket assembly comprises a base having a cavity, a plurality of contacts and a module receiving the contacts and mounted in the cavity of the base. The module has a plurality layers of stacked insulative boards, each insulative board defines a plurality of through holes, and those through holes are aligned to cooperatively define a plurality of individual channels to receive the contacts. 
     Other objects, advantages and novel features of the invention will become more apparent from the following detailed description of a preferred embodiment when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an assembled, perspective view of a socket assembly in accordance with a preferred embodiment of present invention; 
         FIG. 2  is a partially exploded, perspective view of the socket assembly in  FIG. 1   
         FIG. 3  is an exploded, perspective view of the socket assembly; 
         FIG. 4  is similar with  FIG. 3 , but taken from another side; 
         FIG. 5  is a partially assembled, perspective view of the socket assembly; 
         FIG. 6  is a partial sectional view of the socket assembly; 
         FIG. 7  is a perspective view of the socket assembly in  FIG. 6 ; 
         FIG. 8  is a perspective view of a module of the socket assembly; 
         FIG. 9  is a sketch view showing contacts received in the module; 
         FIG. 10  is similar with  FIG. 9 , except that the contacts deflect; and 
         FIG. 11  is a perspective view of a contact of the socket. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIG. 1  to  FIG. 2 , the socket assembly  100  has a base  2 , a module  3 , a plurality of contacts  33  and a cover  4  mounted on the base  2 . 
     Referring to  FIG. 2  to  FIG. 4 , the base  2  has a rectangular configuration with a top surface  23  and a bottom surface  25  and defines a cavity  20  extending through a center thereof. The base  2  has a flange  26  protruding from a top edge of the cavity  20  toward a center of the cavity  20  to limit an upper insulative board  30  of the module  3  from a top side (referring to  FIG. 6 ). A plurality of linking posts  21  upwardly extend from the top surface  23  and around the cavity  20 , and a plurality of recesses  22  are defined between two adjacent linking posts  21  for receiving corresponding springs  36 . A plurality of positioning holes  24  are defined on four corners of the cavity  20  and recessed upwardly from a bottom side of the base  2 . 
     The module  3  has a positioning board  31 , a retaining board  32  and a plurality of layers of stacked insulative boards  30  disposed between the positioning board  31  and the retaining board  32 . The positioning board  31  is assembled on the top surface  23  of the base  2 , the retaining board  32  is retained on the bottom surface  25  of the base  2 , and the insulative boards  30  are received in the cavity  20  of the base  2  as a whole. 
     Referring to  FIGS. 2-4 , the positioning board  31  defines a plurality of holes  310  on four corners thereof and a receiving space  314  in a center thereof. A bottom wall  312  under the receiving space  314  has a plurality of contact passageways  313  for receiving the contacts  33 . The positioning board  31  is mounted on the top surface  23  of the base  2  by a plurality of screws  35  passing through the holes  310  of the posting board  31  and engaging with the linking posts  21  of the base  2 . The springs  36  are mounted between the recesses  22  of the base  2  and the positioning board  31 . 
     The retaining board  32  has a plurality of contact slots  320  for receiving the contacts  33 , and a plurality of retaining posts  321  extending from a top surface thereof for engaging with the positioning holes  24  of the base  2  to limit the insulative boards  30  from a bottom side. Especially referring to  FIG. 4 , the retaining board  32  has a plurality of retaining legs  323  extending downwardly from a bottom surface thereof to orientate the socket assembly  100  on a printed circuit board (not shown). Four engaging holes  322  are provided on four corners of the retaining board  32 . The retaining board  32  is installed to the bottom surface  25  of the base  2  by bolts  34  passing through the engaging holes  322  and engaging with the base  2 . 
     The cover  4  covers the base  2 , and defines a recessed portion  40  recessed upwardly from a bottom surface thereof. After the positioning board  31  is located above the base  2 , the cover  4  is mounted upon the base  2  by bolts (not shown), which pass through a plurality of mounting holes  41  of the cover  4 , then the positioning board  31  is located within the recessed portion  40  of the cover  4 . 
     Referring to  FIG. 8  and  FIG. 9 , the contact  33  has a helical configuration, and comprises a head portion  330  protruding upwardly beyond the positioning board  31  to contact with the IC package (no shown), a middle portion  331  located within the insulative boards  30  and a tail portion  332  extending downwardly beyond of the retaining board  32  to contact with the printed circuit board (not shown). Each insulative board  30  defines a plurality of through holes  301  for the contacts  33  passing through. Each through hole  301  of each insulative board  30  is designed according to the configuration of the contact  33 , when all the insulative boards  30  are stacked together, all the through holes  301  cooperatively define a plurality of helical channels (not shown), which extend in a top-to-bottom direction and are separated with each other, the channel has a substantially same configuration as the contact  33 . The contact  33  inserts into the channel of the insulative board  30  by rotating and moving downwardly, then the insulative boards  30  with the contacts  33  are together put in the cavity  20  of the base  2  from a bottom side, before the retaining board  32  is assembled to the base  2 . 
     When the socket assembly  100  is assembled, the module  3  is assembled with the base  2 , and the cover  4  is located upon the base  2 , the contacts  33  project from the positioning board  31  and the retaining board  32 , respectively. Referring to  FIG. 6  and  FIG. 7 , and conjoined with  FIG. 3 , when using, the cover  4  is firstly removed, then the IC package (not shown) is put in the receiving space  314  above the bottom wall  312  of the positioning board  31 , which abuts against the upper insulative board  30 , then the cover  4  is retained on the base  2  by the blots (not shown) again, the cover  4  provides an evenly distributed force on the IC Package (not shown), the head portion  330  of the contact  33  contacts with the pad (not shown) of the IC package (not shown) and is compressed to deflect downwardly, since all the contacts are received in the channels by a same way, so that the deflected contacts  30  then provide uniform forces on each insulative board  30 , that cause the corresponding insulative board  30  moves along with the contacts  33  in a horizontal direction, that allows the contacts  33  to further deflect, a contours line of the stacked insulative board  30  may become irregular wave shape from original linear shape. The contacts  33  can be reliably retained by the insulative boards  33  of the module  3 , while also can deflect and move in the base  2  to allow the contact  33  to occur elastic deflection without shot circuit. 
     The helical contact  33  of the socket assembly  100  is inserted into the stacked insulative board  30  by rotational manner, the contacts  33  can have a small pitch, so that the contacts  33  can be arranged in a high density, and the socket assembly  100  can adapt to an IC package with a smaller volume and high transmission speed. When the contact  33  contacts with the IC package (not shown), the insulative boards  30  move along with the contacts  33  so that the contacts  33  are allowed to further deflect and reliably contact with the IC package (not shown). 
     Furthermore, the contacts  3  may not insert all of the channels, but some selected channels, according to the pads of the IC package. 
     However, the disclosure is illustrative only, changes may be made in detail, especially in matter of shape, size, and arrangement of parts within the principles of the invention.