Patent Publication Number: US-6902442-B2

Title: Electrical connector

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to an electrical connector, and more particularly to an electrical connector having a plurality of terminals securely retained therein. 
   2. Description of the Related Art 
   Electrical connectors are used in a variety of applications. One type of connector is commonly known as a board-to-board connector for interconnecting two circuit boards. A board-to-board connector typically includes interengageable male and female connectors. The female connector typically comprises a slot for connecting with a central mating portion of the male connector. A plurality of terminals is arranged with in the slot with a longitudinal spacing therebetween known as the “pitch”. 
   To promote miniaturization, compact connectors are desirable. The pitch of the terminals is reduced from 0.635 to 0.5 mm and the housing is increasingly thin. A conventional method for forming an electrical connector is to assemble a plurality of terminals in a molded housing. A problem with such a method is that the terminals tend to deform and deflect due to an excessive assembly force during the assembly process. Accordingly, an insert molding method is employed to make small pitch connectors. U.S. Pat. No. 6,155,886 discloses such a board-to-board connector comprising an insulative housing having a pair of side walls each defining a plurality of exposed openings in a top surface thereof, and a plurality of terminals insert molded in the insulative housing. During molding process of the insulative housing, the terminals each can keep a correct position via a protrusion portion of an upper mold. The protrusion of the upper mold needs to extend into the openings of the top surfaces of the side walls, so the flows of molding materials will be obstructed thereby resulting in that an upper portion of the insulative housing will be deformed. 
   Hence, an improved electrical connector is required to overcome the disadvantages of the prior art. 
   SUMMARY OF THE INVENTION 
   A major object of the present invention is to provide an insert-molded electrical connector having terminals exhibiting a better coplanarity to the housing. 
   In order to achieve the object set forth, an electrical connector comprises insulative housing and a plurality of contacts. The insulative housing has two side walls and a slot between the sidewalls. Each side wall defines an elongate cavity and a plurality of openings. The contacts are received in inner surfaces of the side wall. The openings extend inwardly from outer surfaces of the side walls to the contacts. 
   Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an exploded, perspective view of an electrical connector in accordance with the present invention; 
       FIG. 2  is an assembled, perspective view of the electrical connector of  FIG. 1 ; 
       FIG. 3  is a cross-sectional view taken along line  3 — 3  of  FIG. 2 ; 
       FIG. 4  is a cross-sectional view taken along line  4 — 4  of  FIG. 2 ; and 
       FIG. 5  is a partially assembled view of a number of contacts and a molding device. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to  FIGS. 1 and 2 , an electrical connector  1  comprises an insulative housing  10 , a plurality of contacts  2 , a pair of soldering pads  3 . 
   The insulative housing  10  is elongate and comprises a mating face  13  and opposite side walls  12  extending downwardly from the mating face. The mating face  13  defines a slot  14  at a middle portion thereof. Referring to  FIGS. 3-4 , each side wall  12  defines an elongate cavity  11  at an outer surface. A plurality of ribs  111  corresponding to the contact  2  is arranged in the cavity  111 . An upper and a lower ends of the rib  111  respectively form a ramp  112 . A hole  113  is defined between two ribs  111  and includes a cone portion  114  at a rear end thereof for reinforcing the securing strength of contacts  2 . The side wall  12  defines a plurality of V-shaped openings  15  corresponding the contacts  2 . The insulative housing  10  forms a pair of projections  16  at two ends thereof for guiding a complementary connector (not shown) mating with the connector  1 . A pair of retention stations  17  is positioned at bottom ends of the projections  16  and each form a slit  170  for mating with the soldering pad  3 . 
   Each contact  2  comprises an engaging portion  21  received in an inner surface  141  of the slot  14  of the insulative housing  10 , a retention portion  22  secured in a bottom portion of the insulative housing  10 , and a soldering portion  23  soldered to a printed circuit board (PCB). 
   Referring to  FIGS. 4-5 , in forming processes, two rows of the contacts  2  having carriers  24  are first assembled into a molding device  4  and the molding device  4  is utilized to form the connector  1 . The molding device  4  comprises an upper, a lower, a left, and a right molding portions  41 ,  42 ,  43 ,  44 . The left and the right molding portion  43 ,  44  are symmetrical. Thus, the right and the left molding portions  44 ,  43  have the same structures. A molding actor  410  extends downwardly from a lower end of the upper molding portion  41 . A plurality of securing fingers  447  is formed at an upper end of the right molding portion  44  and utilized to secure the contacts  2  between the securing fingers  447  and the molding actor  10 . Each securing finger  447  forms a guiding angle  448  at a rear end thereof. The V-shaped openings  15  are made via the securing fingers  447  and the guiding angles  448  are jet-molded. A plurality of protrusions  440  adjacent to the engaging portions  21  of the contacts  2  is formed at a middle portion of the right molding portion  44  thereof. A recess  442  is formed between the two protrusions  442  for forming the ribs  111  of the insulative housing  10  by jet-molding. The protrusions  440  fix the engaging portions  21  of the contacts  2  for preventing the engaging portions  21  slanting along an extending direction of the insulative housing  10 . 
   Each protrusion  440  forms a guiding angle  441  at a rear end thereof for forming the cone portion  114  of the hole  113 . The recesses each  442  also form a pair of slating portions  443  at an upper and a lower end thereof for corresponding to and molding the ramps  112  of the ribs  111 . A low end of the right molding portion  44  forms a pressing portion  445  pressing the soldering portions  23  of the contacts  2  for securing the soldering portions  23  on the PCB. The carriers  24  are cut from the soldering portions of the contacts  2 . Finally, the soldering pads  3  are installed in the slits  170  of the retention stations  17 , assemblies of the connector  1  are completed. 
   The openings  15  of the side walls  12  of the present invention can provide a function of fixing position to the contacts  2 . At the same time, the openings  15  also can apply flows of molding materials smooth on an upper end of the inner surface  141  of the slot  14 . So, planarity of a bottom end of the insulative housing  10  can be improved. 
   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.