Patent Publication Number: US-6210234-B1

Title: Contact for board to board connector

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a connector, and particularly to a surface mounted board to board connector. 
     2. Brief Description of the Prior Art 
     U.S. Pat. No. 5,620,342 issued on Apr. 15, 1997 to The Whitaker Corporation, discloses a socket connector. As shown in FIG. 4, the socket connector  6  has an elongate slot  70  defined in a housing  60  thereof for receiving a daughter card and a plurality of contacts  61 ,  71  spaced apart along the length of the slot  70 . Each of the contacts  61  includes a base section  62  interferentially fitting against a side wall  601  and a central rib  602  of the housing  60 , an arcuate section  64  angularly extending from the base section  62  and an engaging section  66  extending into the slot  70  upwardly from the arcuate section  64 . The contacts  61  and  71  are essentially identical except for the heights of the engaging sections  66  and  76  thereof. 
     The arcuate section  64  angularly extends from the base section  62  and bends only once, thereby providing a low normal force exerted by the connector  6 . However, the connector  6  can not be suitable for low profile applications. 
     Hence, an improved electrical connector is required to overcome the disadvantages of the prior art. 
     BRIEF SUMMARY OF THE INVENTION 
     A first object of the present invention is to provide a connector with a plurality of contacts which provides low normal force and low profile thereof. 
     To achieve the above-mentioned object, a connector includes an elongate housing having a pair of side walls, a central wall defining two rows of chambers on either side thereof, and a pair of slots respectively defined between the side walls and the central wall, and a plurality of contacts received in the chambers. 
     The contacts each include a base, an arcuate beam upwardly depending from the base, and a U-shaped engaging beam extending upwardly from the arcuate beam. The arcuate beam bends twice and so forms a lower curved portion and an upper curved portion. The engaging beam extends into the slot and has a top curved portion. 
     The base forms an inner leg and an outer leg on an upper edge thereof for engaging a side wall of the housing therebetween, thereby securing the contact in the chamber. The inner leg has a plurality of barbs for interferentially engaging with the side wall and the base further forms a bump at an inward surface thereof for interferentially fitting with the central wall, helping to fix the contact in position. 
     The contact provides low normal force exerted by the engaging beam and is adapted for low profile applications. 
     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 
     FIG. 1 is an exploded view of an electrical connector of the present invention; 
     FIG. 2 is a cross-sectional view of the assemble connector of FIG. 1; 
     FIG. 3 is a perspective view of one of contacts of the connector of FIG. 1; and 
     FIG. 4 is a cross-sectional view of a prior art connector. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, an electrical connector  1  of the present invention comprises an elongate dielectric housing  10  and two rows of contacts  20  arrayed longitudinally along the housing  10 . The housing  10  has a substrate (not labeled), a pair of side walls  13  upwardly extending from the substrate (not labeled) and an upward central wall  12  interposed between the side walls  13  thereby defining a pair of slots  11  respectively between the central wall  12  and the side walls  13 . The slots  11  extend through the substrate (not labeled). The central wall  12  defines opposite pairs of chambers  15  along opposite sides and communicating with a slot  11  thereof for receiving the plurality of contacts  20 . Each side wall  13  defines a plurality of recesses  131  in an interior side thereof. 
     Each contact  20  is stamped from a sheet of metal plate and includes, referring to FIGS. 2 and 3, a base  21 , an arcuate beam  23  depending upwardly from the base  21 , and a U-shaped engaging beam  24  extending upwardly from the arcuate beam  23  and extending into the slots  11  for electrical connection with a mated plug (not shown). 
     The base  21  forms an outer leg  211  and an inner leg  212  upwardly projecting therefrom. The inner leg  212  forms a plurality of barbs  213  projecting toward the outer leg  211  on an outward side thereof for interferentially mating with the recess  131 . The legs  211  and  212  together engage a side wall  13  therebetween, thereby securing the contact  20  in the chamber  15 . The base  21  further forms a bump  214  at an inward surface thereof for interferential fitting with the central wall  12 , helping to fix the contact  20  in the chamber  15  of the housing  10 . 
     The arcuate beam  23  initially extends vertically, pressing against the central wall  12  and thus ensuring the rigidity of the contact  20 , and then curves twice, thereby forming two curved portions, one being termed a lower curved portion  231  and the other being termed an upper curved portion  232 . The bend of the lower curved portion  231  is adjustable during manufacturing allowing the normal force provided by the contact  20  to be adjusted. Increasing the manufactured radius of the lower curved portion  231  reduces the normal force provided by the contact  20  and therefore less mating force is required during engagement with a complementary connector (not shown). 
     The U-shaped engaging beam  24  has a top curved portion  241  at an apex thereof. The top curved portion  241  defines a radius which can be adjusted during manufacturing to lessen the yielding of the contact  20 . Increasing the radius of the top curved portion  241  lessens the yielding of the contact  20 . 
     The contacts  20 , in assembly, are inserted into respective chambers  15  from a bottom of the housing  10 . The inner legs  212  and the outer legs  211  cooperate to clamp a side wall  13  and the bumps  214  interferentially fit with the central wall  12 , thereby securing the contacts  20  in position. 
     In use, when the terminals of a complementary connector (not shown) are inserted into the slots  11  of the housing  10 , they mate with corresponding engaging beams  24  of the contacts  20  of the connector  1 . Therefore, the engaging beams  24  outwardly deflect, causing the radiuses of the top curved portions  241  to decrease and the radii of the upper curved portions  232  to increase. Moreover, the radii of the lower curved portions will decrease. The normal force against the complementary connector (not shown) increases. The mated complementary connector (not shown), therefore, bears a larger normal force than it bears during initial insertion thereby retaining the complementary connector (not shown) in mated connection when an unwanted vibration or withdrawing force occurs. 
     It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of 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.