Patent Publication Number: US-2004058566-A1

Title: Electrical connector with resilient reinforced fasteners

Description:
BACKGROUND OF THE INVENTION  
       [0001] 1. Field of the Invention  
       [0002] The present invention relates to an electrical connector for electrically connecting an electronic package such as a land grid array (LGA) chip with a circuit board such as a printed circuit board (PCB), and particularly to a two-part electrical connector with fasteners and mounting holes.  
       [0003] 2. Description of Prior Art  
       [0004] Electrical connectors are widely used in personal computer (PC) systems to electrically connect land grid array (LGA) chips with printed circuit boards (PCBs). A typical electrical connector comprises an insulative housing, and a frame mounting on the housing. One or more fasteners fix the housing and the frame together. Thereby the LGA chip connects electrically with the PCB.  
       [0005] A conventional electrical connector is disclosed in “Nonlinear Analysis Help Design LGA Connectors” (CONNECTOR SPECIFIER, February 2001), for connecting an LGA chip with a PCB. U.S. Pats. Nos. 4,504,105, 4,621,884, 5,302,853, 4,692,790 and 5,344,334 all disclose a conventional fastener used in an electrical connector.  
       [0006] Referring to FIGS. 4, 5, and  6 , a conventional electrical connector  9  comprises an insulative housing  91  and a frame  92 . A pair of fasteners  912  upwardly protrudes from two diagonally opposite corners of the housing  91 , respectively. A pair of through mounting holes  921  is defined in two diagonally opposite corners of the frame  92 , corresponding to the fasteners  912  respectively. Each fastener  912  comprises a pair of symmetrical resilient posts  913 . A recess  914  is formed between the resilient posts  913 , thus the resilient posts  913  are cantilevers. Each resilient post  913  comprises a lower first cylindrical post  916  extending from a top surface of the housing  91 , and a top second conical post  915  above the first cylindrical post  916 . The top second conical post  915  has a locating face  917  parallel to the top surface of the housing  91 .  
       [0007] In assembly of the housing  91  and the frame  92 , the frame  92  is positioned above the housing  91 . The top second conical posts  915  of the resilient posts  913  of the fasteners  912  are deformably inserted through the mounting holes  921  of the frame  92 . When the top second conical posts  915  of the fastener  912  have completely passed through the mounting holes  921  of the frame  92 , the top second conical posts  915  rebound to their original shapes such that the locating faces  917  of the top second conical posts  915  fittingly abut a top surface of the frame  92 . Thus, the housing  91  is attached to the frame  92 .  
       [0008] However, during assembly, each resilient post  913  is exerted upon by an inside wall of the of the frame  92  at the corresponding mounting hole  921 . Thus, one end of the resilient post  913  proximate to the housing  91  sustains deformation. In addition, the resilient posts  913  are cantilevers. Accordingly, the resilient posts  913  are prone to distortion, and may even rupture after repeated assembly and disassembly. This results in the housing  91  not being securely attached to the frame  92 .  
       [0009] A new electrical connector that overcomes the above-mentioned problems is desired.  
       SUMMARY OF THE INVENTION  
       [0010] An object of the present invention is to provide an electrical connector having fasteners and mounting holes that facilitates stable assembly of a housing of the connector to a frame of the connector.  
       [0011] In order to achieve the above object, an electrical connector with fasteners and mounting holes in accordance with a preferred embodiment of the present invention comprises an insulative housing, and a frame mounting on the housing. A pair of fasteners protrudes from a pair of diagonally opposite corners of the housing, respectively. Each fastener comprises a lower portion connecting with a top surface of the housing, a medial portion above the lower portion, and a top cap above the medial portion. A central blind hole is defined in the top cap and medial portion of the fastener. The frame defines a pair of mounting holes corresponding to the fasteners, respectively. A diameter of each mounting hole is substantially the same as a diameter of the medial portion of either fastener. A maximum diameter of each top cap is slightly greater than the diameter of either mounting hole.  
       [0012] 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, in which: 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0013]FIG. 1 is a simplified, exploded isometric view of an electrical connector in accordance with the preferred embodiment of the present invention, together with an LGA chip;  
     [0014]FIG. 2 is a partly cut-away view of the components of FIG. 1 assembled together;  
     [0015]FIG. 3 is an enlarged view of a circle portion III of FIG. 2;  
     [0016]FIG. 4 is a simplified, exploded isometric view of a conventional electrical connector, together with an integrated circuit (IC) chip;  
     [0017]FIG. 5 is a partly cut-away view of the components of FIG. 4 assembled together; and  
     [0018]FIG. 6 is an enlarged view of a circle portion VI of FIG. 5. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
     [0019] Reference will now be made to the drawings to describe the present invention in detail.  
     [0020] Referring to FIGS. 1 and 3, an electrical connector  1  in accordance with the preferred embodiment of the present invention comprises an insulative housing  11 , and a frame  12  mounted on the housing  11 .  
     [0021] The housing  11  comprises a multiplicity of terminals (not shown) received therein, for electrically connecting the connector  1  with a PCB (not shown). A pair of generally post-shaped fasteners  112  extends upwardly from diagonally opposite corners of the housing  11 , respectively. Each fastener  112  comprises a solid cylindrical lower portion  114  connecting with a top surface of the housing  11 , a hollow cylindrical medial portion  117  above the lower portion  114 , and a conical top cap  113  above the medial portion  117 . A maximum diameter of the top cap  113  is slightly greater than that of the medial portion  117 . The top cap  113  has an annular bottom locating face  116  that is parallel to the top surface of the housing  11 . A central blind hole  115  is defined in the top cap  113  and medial portion  117  of the fastener  112 . Therefore, a top section of the fastener  112  comprising the top cap  113  and medial portion  117  is hollow. In addition, the lower cylindrical portion  114  of the fastener  112  is solid. Thus, a structure of the lower cylindrical portion  114  of the fastener  112  is reinforced.  
     [0022] An LGA chip  2  is mounted on the frame  12 , so that the LGA chip  2  is connected with the PCB. A pair of mounting holes  121  is defined in diagonally opposite corners of the frame  12  respectively, corresponding to the fasteners  112  of the housing  11 . A diameter of each mounting hole  121  is substantially the same as the diameter of the medial portion  117  of either fastener  112 . A maximum diameter of each top cap  113  is slightly greater than the diameter of either mounting hole  121 .  
     [0023] Referring also to FIG. 2, in assembly of the frame  12  and the housing  11 , the frame  12  is positioned above the housing  11 . The top caps  113  of the fasteners  112  of the housing  11  are deformably inserted through the mounting holes  121  of the frame  12 . When the top caps  113  have completely passed through the mounting holes  121 , the top caps  113  rebound to their original shapes such that the locating faces  116  of the top caps  113  fittingly abut a top surface of the frame  12 . Thus, the frame  12  is securely attached to the housing  11 . Because said top sections of the fasteners  112  are hollow, the top caps  113  have enhanced resiliency and flexibility. Therefore, the top caps  113  can readily pass through the mounting holes  121  of the frame  12 . Because said structure of the lower cylindrical portions  114  of the fasteners  112  are reinforced, the lower cylindrical portions  114  resist distortion during assembly and in use thereafter. The risk of damage to the fasteners  112  is minimized. Because the maximum diameters of the top posts  113  of the fasteners  112  are slightly greater than the diameters of the mounting holes  121 , the housing  11  remains securely and stably attached to the frame  12  in use. Accordingly, signal transmission between the LGA chip and the PCB is stable and reliable.  
     [0024] While a preferred embodiment in accordance with the present invention has been shown and described, equivalent modifications and changes known to persons skilled in the art according to the spirit of the present invention are considered within the scope of the present invention as defined in the appended claims.