Patent Publication Number: US-6705902-B1

Title: Connector assembly having contacts with uniform electrical property of resistance

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is related to a connector assembly functioning as power parts of a corresponding backplane connector assembly, especially to a connector assembly having a special power contact arrangement to get balanced and steady current transmission beside the backplane connector assembly which is used to connect with a daughtercard and a backplane or motherboard. 
     2. Description of the Related Art 
     Many present day telecommunications systems, computer systems, etc. include a number of printed circuit boards or cards which plug into a backplane or motherboard of the systems to enhance or complete performances of the systems. The backplane or motherboard generally provides a pathway by which the printed circuit boards or cards communicate with each other. In addition, the backplane provides power as well as a reference voltage or ground to each of the printed circuit boards. Conventionally, the parts for power or ground are arranged right beside or around the signal contacts of a backplane connector as attachments of this connector, as shown in Johnson et al. U.S. Pat. No. 4,655,518, Madore et al. U.S. Pat. No. 4,973,260, Buchter U.S. Pat. No. 5,582,519 and Lemke et al. U.S. Pat. No. 6,325,644. Usually different locations or structures for the power or ground parts inside the backplane connector are considered to function in their own ways for specialized performances like EMI shielding, crosstalk suppressing, power supply, etc. For the power application, high current setting is unpractical and undesired for these conventional connectors due to possible noise induced in the neighboring signal contacts by high current through the power parts. And trend of high density contact arrangement and minimization of electronic parts results in much difficulty of manufacturing connectors due to less available space for the installation of power or ground parts without affecting the normal function of signal contacts. 
     Therefore, independent, modularized power parts are considered to adopt to solve the minimization and noise problem in the arts. As introduced in Weber et al. U.S. Pat. No. 4,790,763, Weber U.S. Pat. No. 4,818,237, Fedder et al. U.S. Pat. No. 5,158,471 and Provencher U.S. Pat. No. 5,360,349, modularized power parts being able to programmably latch on signal contact parts are disposed next to the signal contact parts to form corporately with the signal contact parts a complete backplane connector. Alternately, Demler et al. U.S. Pat. No. 4,881,905, Barkus et al. U.S. Pat. No. 5,139,426 and Clark et al. U.S. Pat. No. 6,319,075 all show an independent power connector mounted at different location from the one of the signal connector on the backplane or daughtercard. Obviously, additional space on the backplane and daughtercard must be reserved for extra power parts and independent power connectors. More manufacturing processes are needed to make the parts or connectors, and sometimes the extra processes cost high. 
     Besides, as shown in the &#39;075 patent of Clark et al., all of the contacts of the power connector are arranged in a row along the lengthwise direction of the connector housing so that the contacts are positioned vertically, and the direction is usually parallel to the surface of a printed circuit board when the power connector is seated on the printed circuit board. For a power connector with a large number of contacts, the size of the power connector is enlarged to accept all of the parallel-arranged contacts. Obviously the enlarged power connector is sometimes occupied more room than being expected, and the manufacturing process of the connector becomes complex too. Therefore, another thought for designing the connector is trying to place the contacts as a horizontal row along the direction perpendicular to the printed circuit board so that the contacts look like stacking vertically with each other. The different thought is helpful for the connector design due to the feature of space-saving and size-minimizing. However, the stacked arrangement of contacts varies the shape of contacts due to their installed positions. Obviously the top contact stacked highest is longer than the bottom contact because the distance between the installed position of the top contact and the printed circuit board where the connector is seated is farthest. The result of difference lengths of contacts causes different bulk resistance for each contact, which lowers the current rating through contacts with high resistance and induces the difficulty of circuitry designing. 
     SUMMARY OF THE INVENTION 
     Therefore, an object of the present invention is to provide a power connector assembly having plug and receptacle parts with uniform electrical properties like resistance in order to achieve stable electrical performance for safety of the circuitry of printed circuit boards where component connectors of the connector assembly are mounted. 
     Another object of the present invention is to provide a power connector assembly having a compact part arrangement to assemble its parts in order to minimize its component connectors and the final backplane connector assembly with signal connector parts. 
     Another object of the present invention is to provide a power connector assembly having an idealized distribution of power current density per unit area on the mating faces of mated connectors of the connector assembly to get the maximum current carrying capacity and facilitate assembling of the power connector assembly with other signal ones. 
     To obtain the above objects, a connector assembly in accordance with the present invention includes a plug connector and a receptacle connector mated with the plug connector. The plug connector has a housing with a plurality of passageways to receive the same number of plug conductors. Each plug conductor has a contacting portion extending out of the housing, a retention portion staying in the housing to fix the conductor therein, and a tail portion extending out of another side of the housing to further connect to a printed circuit board. Meanwhile, the receptacle connector has a complementary housing with a plurality of passageways to receive the same number of receptacle conductors configured to mate with the plug conductors. Each receptacle conductor has a contacting portion installed in its corresponding passageway, a retention portion next to the contacting portion to fix the conductor in the passageway, and a tail portion extending out of the housing to further connect to another printed circuit board. 
     Specially, most of conductors of the plug and receptacle connector are arranged in a row along a first direction parallel to printed circuit boards where the connectors are seated respectively. And at least one conductor of the plug or receptacle connector is located beside others and arranged along a second direction perpendicular to the first direction. Controllable electrical property and maximum current carrying capacity of the conductors in the connector assembly is easily acquired due to the specially arranged conductors. And the size of the connector assembly can be compact to meet the need of structural simplification and become easier to be assembled with other backplane connector parts. 
     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 a perspective view of an electrical connector and its mating complementary connector of a connector assembly in accordance with the present invention; 
     FIG. 2 is a perspective view of the electrical connector as shown in FIG. 1 in accordance with the present invention; 
     FIG. 3 is an explored view of the electrical connector as shown in FIG. 2 in accordance with the present invention; 
     FIG. 4 is a perspective view of the mating complementary connector as shown in FIG. 1 in accordance with the present invention; 
     FIG. 5 is an explored view of the mating complementary electrical connector as shown in FIG. 4 in accordance with the present invention; 
     FIG. 6 is a sectional view of the electrical connector and its complementary connector showing the mating situation along the  6 — 6  line in FIG. 1; 
     FIG. 7 is a sectional view of the electrical connector and its complementary connector showing the mating situation along the  7 — 7  line in FIG.  1 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 1 to  3 , the electrical connector  2  in accordance with the present invention is shown mating with its complementary connector  3  to form a connector assembly  1 . The plug type electrical connector  2  as shown in FIG. 2 includes an insulated housing  20  and a plurality of power conductors  21  installed inside the housing  20 . A receiving space  201  (as shown in FIG. 6 or  7 ) is formed in the housing  20  and a mating face  202  is formed on one outer side of the housing  20  beside the space  201 . A plurality of passageways  203 , each of them is used to receive portions of every conductor  21  correspondingly, is formed on the mating face  202  and extends through the mating face  202  to communicate with the receiving space  201  of the housing  20 . Most of these passageways  203  are arranged vertically in a row along a first direction parallel to a printed circuit board (not shown) where the plug connector  2  is seated. But at least one passageway  203  is located beside others and arranged along a second direction perpendicular to the first direction. Two guide posts  204  protrude from the mating face  202  and are located abutting against two opposing edges of the mating face  202 . A sidewall  205  with several guiding ribs formed thereon projects from the mating face  202  as well and extends from another edge of the mating face  202 . Besides, a rear part  24  as a plastic plane-like piece is disposed at the back of the housing  20 . Two upright posts  241  with retention ribs formed thereon extend from the central area of the rear part  24 , and two engaging portions  242  are formed at two neighboring corners of the rear part  24  in order to fasten the rear part  24  onto the housing  20 . 
     Power conductors  21  includes several first conductors  22  and at least one second conductor  23 . Each first conductor  22  is arranged as an upright metal plate before it is installed into the corresponding passageway  203  and fixed therein by passing through the receiving space  201  from the back of the housing  20 . At least two contacting portions  221  extend from the main body of every first conductor  22  with a slot formed therebetween. At the end of the slot, a retention portion  222  having several barbs is formed in order to engage with an inner wall inside the passageway  203  where the first conductor  22  is installed and to fix the first conductor  22  therein. Tail portions  223 , extending vertically from one edge of the body of every first conductor  22 , are arranged in a row along the edge. The second conductor  23 , on the contrary, is an L-shaped metal plate having two extending contacting portions  231  formed at its one end and several tail portions  233  formed at the other end. A severed window-like retention portion  232  having a resilient arm formed therein is disposed next to the contacting portions  231  on the top plate section of the second conductor  23  so that the resilient arm of the retention portion  232  can engage with inner sidewalls of the passageway  203  where the second conductor  23  is going to be installed in order to fix the second conductor  23  therein. And at least two openings  234  are formed on the lateral plate section of the second conductor  23 . Either the first or second conductor  22 ,  23  is inserted into the housing  20  through the receiving space  201  from the back of the housing  20 , and is fixed inside its corresponding passageway  203  by its own retention portion  222 ,  232 . The contacting portion  221 ,  231  of every conductor  21  then extends beyond the mating face  202  of the housing  20  beside the guide posts  204  when the conductors  21  are fully inserted. Afterwards, the rear part  24  is mounted onto the housing  20  with its two posts  241  fixedly penetrating through the corresponding openings  234  of the second conductor  23  respectively to position the rear half of the second conductor  23 . 
     Referring particularly to FIGS. 4 and 5, the mating complementary connector  3  of the connector assembly  1  includes an receptacle-typed housing  30  and a plurality of power conductors  31 ,  32  installed therein. The housing  30  adapted to mate with the plug connector  2  comprises a mating face  301  formed on its one side and a plurality of passageways  302  extending inside the housing  30  from the mating face  301  to the face opposing to the mating face  301 . Some of the passageways  302  are arranged in a row by locating every passageway  302  in one plane of a group of imaginary planes parallel to each other, and at least one passageway  302  is located beside the passageway row by locating the at least one passageway  302  in an imaginary plane basically perpendicular to any of the former parallel imaginary planes. Two channels  303  are respectively located on two opposite surfaces with a predetermined extending length on the surfaces neighboring the mating face  301  and both have a communicating opening on the mating face  301 . 
     The power conductors installed in the receptacle housing  30  includes several first conductors  31  and at least one second conductor  32 . Each first conductor  31  has a plate-like retention portion  312  with several retention dot protrusions formed thereon. Several tail portions  313  extend from one side of the retention portion  312  and are arranged in one row. Pairs of resilient contacting portions  311  extend from another side of the retention potion  312  along a direction opposing to the extending direction of tail portions  313  while each contacting portion  311  of the same pair is bent away from each other to form a fork-like mating portion. Each first conductor  31  is installed in its corresponding passageway  302  arranged in the same row to have its contacting portions  311  staying therein. The second conductor  32  is basically identical to any of the first conductors  31  except the second conductor  32  is installed in the at least one passageway  302  arranged differently from others. Therefore the second conductor  32  has a contacting portion  321 , a retention portion  322  and several tail portions  323  and all of them are configured same as the first conductors  31 . 
     Referring to FIGS. 1,  6  and  7 , it is understandable, when the electrical connector  2  and its complementary connector  3  of the connector assembly  1  is going to be mated, the guide posts  204  of the plug connector  2  is first inserted into the channels  303  of the receptacle connector  3  to guide these two connectors  2 ,  3  moving to the right mating position while the sidewall  205  of the plug housing  20  abuts against a corresponding lateral side of the receptacle housing  30  for the similar reason. Then, the expending contact portions  221 ,  231  of the conductors  21  beyond the mating face  202  of the housing  20  are aligned with openings formed on the mating face  301  of the receptacle housing  30  leading to the passageways so as to be inserted into the passageways  302  respectively and finally engage with the receptacle conductors  31 ,  32  installed therein for establishing electrical transmission paths. 
     Obviously, the identical first conductors  31  and second conductor  32  of the receptacle connector  3  have the same resistance property when power current pass through them. However, the resistance of the first and second conductors  22 ,  23  of the plug connector  2  follow the formula stated as below: 
     
       
         R=ρL/A 
       
     
     wherein R means resistance of a conductor, ρ is resistivity of the conductor, L is the length of the conductor, and A means the cross sectional area of the conductor. It is understood that the length of the second conductor  23  is longer the one of any first conductor  22 , but the cross sectional area of the second conductor  23  is bigger than the one of any first conductor  22  at the same time. Therefore, the resistance of the first and second conductors  22 ,  23  is controlled to be same by adjusting the length and cross sectional area of the second conductor  23  so that the electrical current passing through the conductors  21  will be uniform and much stable. This makes the whole connector assembly  1  can achieve better electrical performance and adds the facilitation to simplify the structure and use of the connector assembly  1 . 
     Usually, the connector assembly  1  in accordance with the present invention is a part of a backplane connector assembly wherein the plug connector  2  is probably mounted on a daughter board (not shown) by being arranged next to a signal-transmitting connector part, and the receptacle connector  3  is probably mounted on a backplane or motherboard with another signal-transmitting connector part being mated with the former one. Due to the compact size the connector assembly  1  has, the plug connector  2  and receptacle connector  3  of the connector assembly  1  are easy to become modularized or assembled with other backplane connector components or parts. 
     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.