Patent Publication Number: US-7588468-B2

Title: Electrical connector with improved preloading structure

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to an electrical connector having electrical contacts for electrically connecting a daughter card to a mother board, and more particularly, relates to preloading features of the electrical contacts for decreasing an insertion force applied on the electrical component when the electrical component is mated into the electrical connector. 
   2. Description of the Prior Art 
   A card edge electrical connector is disclosed with preloading structures in U.S. Pat. No. 5,041,023 issued on Oct. 10, 1995. The electrical connector includes an insulating housing defining a slot for receiving a mating daughter board and a number of electrical contacts lined along two opposite sides of the slot. Each of the electrical contacts includes a securing portion for securing the electrical contact in the housing, a flexible arm extending from the securing portion with a bight interface extending into the slot for electrically contacting the mating daughter board, and an electrical stub sequentially extending above the bight interface for abutting a side wall of the receiving slot. However, in a high speed application, the length of the electrical stub is detrimental to the signal integrity. 
   Hence, an improved electrical connector is needed to decrease the length of electrical stub above the bight interface and improve the signal integrity. 
   BRIEF SUMMARY OF THE INVENTION 
   One object of the present invention is to provide an electrical connector with lower insertion force and improved signal integrity. 
   An electrical connector comprises an insulating housing and a plurality of electrical contacts. The insulating housing defines a receiving cavity for mating with an mating electrical component therein. Each of said electrical contacts has a securing portion for securing said contact in said housing, a connecting portion extending from said securing portion and a contacting portion extending sequentially from the connection arm into said receiving cavity. The insulating housing forms a stop portion abutting said connecting portion for preventing said contacting portion from further moving into said receiving slot when said mating electrical component is not mated therein. The electrical contact is preloaded on the connecting portion, so that the length of the electrical stub can be shortened to improve the signal integrity. 
   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 
     The features of this invention which are believed to be novel are set forth with particularity in the appended claims. The invention, together with its objects and the advantages thereof, may be best understood by reference to the following description taken in conjunction with the accompanying drawings, in which like reference numerals identify like elements in the figures and in which: 
       FIG. 1  is a perspective view of an electrical connector according to the present invention; 
       FIG. 2  is a sectional view of the electrical connector shown in  FIG. 1  (with a contact insert is omitted for clearly shown); 
       FIG. 3  is another sectional view similar to the  FIG. 2 ; and 
       FIG. 4  is partial perspective view of a contact insert with a few of the contacts. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Reference will now be made to the drawing figures to describe the present invention in detail. 
     FIG. 1  shows an electrical connector  100  mounted on a mother board  800  according to the present invention. The electrical connector  100  comprises an insulating housing  20  and two contact inserts  40 . 
   Referring to  FIGS. 2-3 , the insulating housing  20  forms a pair of mutual opposite side walls  22  and a bottom wall  24  to define a longitudinal mating slot  220  above the bottom wall  24  for receiving an edge of a daughter card (not shown). The side walls  22  have lower portions  224  aligning with and sandwiching the bottom wall  24 . The insulating housing  20  further defines a pair of cavities  240  between lower portions  224  of side wall  22  and the bottom wall  24 . Each of the side walls  22  forms a row of contact passageways  26  extending upwardly from corresponding cavity  240  and communicating the receiving slot  220 . The contact passageways  26  cut through the side wall  22 . The side walls  22  further forms a pair of ribs  226  oppositely protruding into each of the contact passageways  26 . The pair of ribs  226  are symmetrically located at an entrance of corresponding contact passageway  26  into the receiving slot  220 . 
   Either of the contact insert  40  includes a insulating bar  42  and a row of electrical contacts  60  having a securing portion (not shown) molded over by the insulating bar  42 . Each of the electrical contacts  60  further includes a soldering tail  62  extending downwardly from the securing portion, a connecting portion  64  extending upwardly from the securing portion, a contacting portion  66  extending from an upper end of the connecting portion  64  and a guiding portion  68  extending sequentially upward from the contacting portion  66 . The connecting portion  64  forms a flexible straight cantilever received in corresponding contact passageways  26  and a pair of bulges  641  protruding sideway for abutting on corresponding pair of ribs  226 . The contacting portion  66  forms a bight interface crooking into the receiving slot  220  for mating with the inserted daughter card. The guiding portion  68  extends above the interface and having a little-length free end  681  slantwise extending into corresponding passageway  26 . 
   When the daughter card is not mated in the receiving slot  220 , the connecting portion  64  flexibly biases the abutting of the bulges  641  of the connecting portion  64  on the ribs  226  of the housing  20 . As disclosed in  FIG. 4 , the bulges  641  of the connecting portion  64  are disposed at different height, so that the capacitance between adjacent bulged  61  decreases comparing to the capacitance when the bulges  641  of the connecting portion  64  were disposed at the same height. 
   It is to be understood, however, that even though numerous, characteristics and advantages of the present invention have been set fourth in the foregoing description, together with details of the structure and function of the invention, the disclosed is illustrative only, and changes may be made in detail, especially in matters of number, 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.