Patent Publication Number: US-7591684-B2

Title: Electrical connector

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a board to board connector. 
     2. Description of Related Art 
     A board to board connector assembly is used to electrical link two print circuit boards. Some equipments, such as HD (“Hard Disk”), need a high working power, and a high quality signal transmission. A board-to-board connector used for connecting HD is capable of transmitting high current and high-frequency signals, steadily, furthermore, the connector must prevent cross-interference between signals. Present board-to-board connectors can not fully meet the above requirements, and do not have a perspective impedance to make sure the connector steadily transmits the high current and high-frequency signals. 
     U.S. Pat. No. 6,783,400 discloses such a board-to-board connector having an insulting housing and a plurality of contacts received in the insulating housing, the contacts include a plurality of signal contacts, a plurality of grounding contacts and a plurality of shielding contacts, wherein every two signal contacts has a grounding contact or a shielding contacts disposed therebetween to form a contact group, and each contact group has a distance with adjacent contact group. By this way, the connector can obtain a perfective impedance and reduce cross-interference between the signal contacts. But the connector having such contact array still can not fit the requirements for linking HD. 
     Hence, an improved connector is required to overcome the disadvantages of the prior art. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a connector which can steadily transmitting current and signals. 
     Accordingly, to achieve above-mentioned object, an electrical connector comprises a longitudinal insulating housing defining a plurality of grooves and a plurality of contacts received in the grooves, each contact having a contacting arm, a retaining portion retained into the insulating housing and a soldering portion. The contacts comprises a plurality of signal contacts and grounding contacts, at least two signal contacts define a signal group and at least one grounding contact defines a grounding group, each signal group and each grounding group are alternately arranged, a distance between a signal group and a adjacent grounding group is larger than a distance of adjacent signal contacts in a same signal group. 
     Other objects, advantages and novel features of the present 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 a perspective view of an electrical connector of the present invention and a receptacle connector; 
         FIG. 2  is another perspective view the electrical connector of the present invention; 
         FIG. 3  is a partial enlarged view of the electrical connector; 
         FIG. 4  is sectional view of the electrical connector, taken from line  4 - 4 ; 
         FIG. 5  is an perspective view of the receptacle connector. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference will now be made in detail to the preferred embodiment of the present invention. 
     Referring to  FIG. 1 , the electrical connector  10  in accordance with the present invention is used to be mounted to a print circuit board (not shown) and mates with a complementary connector  20 , the electrical connector  10  comprises an elongated insulating housing  11  and a plurality of contacts  12  received in the insulating housing  11 . The complementary connector  10  comprises an elongated insulating housing  21  and a plurality of contacts  22  received in the insulating housing  21 . 
     Referring to  FIGS. 1 and 2 , the insulating housing  11  of the electrical connector  10  has a main body  110  and two mounting portions  111  extending from a bottom edge of two opposed ends of the main body  110 . The main body  110  has a peripheral wall  1101 , a mating portion  1103  extending from center thereof and surrounded by the peripheral wall  1101 , a pair of recess  1102  between two ends of the mating portion and the peripheral wall  1101 , and a rectangles room (not labeled) defined by the peripheral wall  1101  below the mating portion  1103 . The peripheral wall  1101  comprises two longitudinal walls and two end walls higher than the longitudinal walls, each longitudinal wall is formed with a plurality of protruding portions  1105  on an outside surface thereof (referring to  FIG. 2 ), an uncontinuous top edge  1109  of each longitudinal wall up the protruding portions  1105  is thinned from an inner side. Each end wall is formed with a guiding surface  1106  on an inner surface thereof for guiding the complementary connector  20 . The mating portion  1103  is higher than the longitudinal walls and lower than the end walls, the mating portion  1103  has two anti-mismating ribs  1104  on opposed ends thereof. The mating portion  1103  defines a plurality of upright grooves  1107  on two opposed side surfaces thereof, which are arranged along a longitudinal direction. The groove  1107  and further extending downwardly though the insulating housing  11  to communicate with the room, and the longitudinal wall defines a plurality of upright slots  1108  on an inner surface thereof (referring to  FIG. 4 ) exposed in the room, each groove  1107  is corresponding to a slot  1108 . The grooves  1107  are equidistant, and the slots  1108  are equidistant too, a distance between midlines of each two adjacent slots  1108  and each two adjacent grooves  1107  is defined as “P”. The mounting portion  111  defines a screw (not labeled) on a center thereof for receiving a blot (not shown) to mount the electrical connector  10  to the print circuit board (not shown). 
     Referring to  FIGS. 1-4 , each contact  12  has a retaining portion (not labeled), an elastic contacting arm  1201  upwardly extending from an end of the retaining portion and a soldering portion  1203  horizontal extending beyond the insulating housing from the other end of the retaining portion for being soldered to the print circuit board. The contacts  12  are assembled into the grooves  1107  and the slots  1108  from bottom to top, an inwardly bended end of the elastic contacting arm  1201  abuts against an inner sidewall of the groove  1107 , the retaining portion has a plurality of stabs  1202  to respectively interferentially engaging with insulating housing  11  to retain the contacts  12 . 
     The contacts  12  comprise a plurality of grounding contacts  120  and a plurality of signal contacts  121 . Two signal contacts  121   a  ,  121   b  and two grounding contacts  120   a  ,  120   b  respectively form a signal group and a grounding group. The signal contacts  121  and the grounding contacts  120  are alternately arranged in the grooves  1107  and slots  1108  by means of each signal group being disposed between two adjacent grounding groups and an empty groove  1107  which do not receive any contact  12  is reserved between each signal group and a adjacent grounding group. Since grounding groups locate on both sides of each signal group, so the signal contacts  121  are prevented from EMI (Electro Magnetic Interference). Furthermore, each two adjacent signal groups have a far distance and have a grounding group disposed therebetween, so cross talk between the signal groups also can be reduced. The arrangement of the grounding contacts  120  and the signal contacts  121  can obtain a preferable impedance to ensure a high transmission quality of high-frequency signals. 
     The contacts  12  further comprise a plurality of power contacts  122 , the grounding and signal contacts  120 ,  121  are alternately disposed on a left end of the mating portion  1103 , the power contacts  122  are continuously disposed on a right end of the mating portion. There is a space between the power contacts  122  and nearest grounding contact  120  and signal contact  121  to prevent the power contact  122  from electro magnetic interfering the grounding contacts  120  and signal contacts  121 . 
     Referring to  FIGS. 1 and 5 , the complementary connector  20  has a housing  21  and a plurality of terminals  22  received in the housing  21 . The housing  21  has a peripheral wall  1101  including two opposed longitudinal walls and two end walls and defines a receiving room  210  surrounded by the peripheral wall  1101  for receiving the mating portion  1103  of the electrical connector  10 . The longitudinal sidewall defines a plurality of upright channels  211  in an inner surface thereof for receiving the terminals  22  and is formed with a plurality of protruding portions  212  on an out surface thereof, and an top edge  213  of each longitudinal wall besides the protruding portions  212  is recessed from an out side thereof. Each end wall of the peripheral wall  1101  has a pair of anti-mismating portions on inner sides thereof, and a top portion  214  of the end wall outwardly protrudes. 
     The terminal  22  also comprises a plurality of grounding terminals  220 , a plurality of signal terminals  221  and a plurality of power terminals  222 , and an arrangement manner of the grounding terminals  220 , the signal terminals  221  and the power terminals  222  is corresponding to that of the contacts  12  of the electrical connector  10 , here we will not give unnecessary details. 
     When the electrical connector  10  engages with the complementary connector  20 , the guiding surfaces  1106  guide two ends of the housing  21  inserting. The top portions  214  of the end walls of the complementary connector  20  received in the recess  1102  to abut against the inner sidewall of the end wall of the electrical connector  10 , and the top edges  1109  of the electrical connector  10  engages with the top edges  213  of the complementary connector  20 , by this way, the complementary connector  20  can fast engage with the electrical connector  10 . Then, the mating portion  1103  of the electrical connector  10  is received in the receiving room  210  of the complementary connector  20 , while the housing  21  is received in, the grounding terminals  220 , signal terminals  221  and the power terminals  222  will electrically contact with corresponding grounding contacts  120 , signal contacts  121  and power contacts  122 , respectively. 
     Otherwise, the signal group or grounding group may only have one contact  12 , and may also have more than two contacts  12 , that will not influence a performance of the signal transmission. 
     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 described in the appended claims.