Abstract:
An electrical connector is provided including an electrical connector having a housing with a front end configured to receive a circuit board and a rear end configured to receive at least one flexible cable. The electrical connector includes top and bottom contacts retained in alignment along a vertical axis in corresponding channels in the housing. At least one of the top and bottom contacts has a first contact prong configured to engage the circuit board and a second contact prong configured to engage the at least one flexible cable. The electrical connector includes a stuffer received at the second end of the housing that is configured to retain the at least one flexible cable in contact with the second contact prong.

Description:
BACKGROUND OF THE INVENTION 
     The present invention generally relates to an electrical connector that connects printed circuit boards to cables and more particularly relates to an electrical connector that connects a daughter board to a flexible cable. 
     In certain computer applications, such as servers, large circuit boards called motherboards are retained within a server cabinet and are electrically connected to several smaller circuit boards called daughter cards. The terms card and board shall be used interchangeably hereafter. Usually a power supply is provided in the server cabinet. The daughter card is connected to a sensing location within the power supply by an electrical connector. The sensing location monitors the power supply throughout the motherboard within the power supply to determine where the electrical power should be routed within the server. 
     Therefore, the typical electrical connector includes a housing having a card slot that receives the daughter card at a first end. The housing carries power contacts and signal contacts which are generally similar in size. The power and signal contacts extend through a second end of the housing to power and signal wires, respectively. The power wires extend to the power supply and the motherboard within the server cabinet, and the signal wires extend to the sensing location. 
     The power contacts are retained in a group on one side of the housing in parallel channels that are perpendicular to the card slot. Each channel carries a top power contact aligned with a corresponding bottom power contact along a vertical axis. The corresponding top and bottom power contacts each have a deflectable contact prong at a first end. The contact prongs of the corresponding top and bottom power contacts extend toward each other into the card slot. Each top and bottom power contact also has a barrel that extends out of the second end of the housing and is crimped around a power wire. The top and bottom power contacts are preloaded within the housing apart from each other along the vertical axis within the channels. When the daughter card is inserted into the card slot, the daughter card biases the top and bottom power contacts in a channel away from each other along the vertical axis such that the top and bottom power contacts press firmly against electrical traces on the top and bottom sides of the daughter card. Thus, the power contacts electrically connect the daughter card to the power supply. 
     The signal contacts are retained in a group next to the power contacts in parallel channels that are perpendicular to the card slot. Each channel carries a top signal contact aligned with a corresponding bottom signal contact along the vertical axis. The corresponding top and bottom signal contacts each have a deflectable contact prong at a first end. The contact prongs of the corresponding top and bottom signal contacts extend toward each other into the card slot. Each top and bottom signal contact also has a barrel that extends out of the second end of the housing and is crimped around a signal wire. When the daughter card is inserted into the card slot, the daughter card deflects the contact prongs of corresponding top and bottom signal contacts away from each other along the vertical axis such that the contact prongs press firmly against electrical traces on the top and bottom sides of the daughter card. Thus, the signal contacts electrically connect the daughter card to the electronic sensor. 
     The typical card-to-wire electrical connector suffers from a number of drawbacks. First, because the power and signal contacts are wide and have a large pitch across the first end of the housing, the electrical connector takes up a great deal of space within the power supply such that the power supply is larger and takes up a great deal of space within the server cabinet. The server cabinet is already tightly packed with printed circuit boards, thus the electrical connector takes up space that could be used for additional printed circuit boards. The electrical connector also blocks air that is forced through the server cabinet to cool the power supply. The power and signal wires extending from the electrical connector take up space within the power supply and server cabinet as well. Additionally, a tool is required to connect the power and signal wires to the power and signal contacts, respectively. The tool is bulky and thus difficult to use in the server cabinet or any other constrained space. Further, it is inconvenient for an operator to always have the available tool to connect the power and signal wires to the electrical connector. Finally, because all the contacts are crimped about the wires, the wires cannot be disconnected from the electrical connector without first removing the contacts from the housing. 
     A need remains for an electrical connector that overcomes the above problems and addresses other concerns experienced in the prior art. 
     BRIEF SUMMARY OF THE INVENTION 
     Certain embodiments of the present invention include an electrical connector having a housing with a front end configured to receive a circuit board and a rear end configured to receive at least one flexible cable. The electrical connector includes top and bottom contacts retained in alignment along a vertical axis in corresponding channels in the housing. At least one of the top and bottom contacts has a first contact prong configured to engage the circuit board and a second contact prong configured to engage the at least one flexible cable. The electrical connector includes a stuffer received at the second end of the housing that is configured to retain the flexible cable in contact with the second contact prong. 
    
    
     BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS 
     FIG. 1 illustrates an isometric view of an electrical connector with a cutaway side portion partially exposing flat flexible cables (FFCs) and power wires formed according to an embodiment of the present invention. 
     FIG. 2 illustrates a more detailed isometric view of the electrical connector, FFCs, and power wires of FIG.  1 . 
     FIG. 3 illustrates an isometric view of an electrical connector with the stuffer removed according to an embodiment of the present invention. 
     FIG. 4 illustrates an isometric view of a top signal contact formed according to an embodiment of the present invention. 
     FIG. 5 illustrates a cutaway isometric view of the electrical connector, FFCs, and power wires of FIG.  1 . 
    
    
     The foregoing summary, as well as the following detailed description of certain embodiments of the present invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there is shown in the drawings, certain embodiments. It should be understood, however, that the present invention is not limited to the arrangements and instrumentality shown in the attached drawings. 
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 illustrates a cutaway side isometric view of an electrical connector  10  formed according to an embodiment of the present invention engaging flat flexible cables (FFCs)  14  and power wires  18 . The electrical connector  10  includes an insulated box-shaped housing  34  with a rectangular top portion  22  and a rectangular bottom portion  26  connected by side walls  30  and a divider wall  38  (only one side wall  30  is shown however because of the cutaway view). The housing  34  has a card slot  42  between the top and bottom portions  22  and  26  at a front end  46  and, at a rear end  54 , a top FFC slot  50  between the top portion  22  and divider wall  38  and a bottom FFC slot  52  between the bottom portion  26  and the divider wall  38 . 
     The housing  34  carries power contacts  58 , each of which has beams  62  aligned opposite each other along a vertical axis  66  at the front end  46 . The beams  62  are formed to be biased toward each other along the vertical axis  66 . The oppositely aligned beams  62  have catches (not shown) that are preloaded in retention cavities  70  such that the beams  62  are biased away from each other. Each power contact  58  has a barrel (not shown) that receives and is crimped about a power wire  18 . The power wires  18  extend to a power supply or a motherboard (not shown). 
     The housing  34  also carries planar H-shaped top and bottom signal contacts  74  and  78 . The top signal contacts  74  are retained in parallel top channels  82  and the bottom signal contacts  78  are retained in parallel bottom channels  86 . Each top signal contact  74  is aligned opposite a corresponding bottom signal contact  78  along the vertical axis  66 . The top and bottom signal contacts  74  and  78  have contact prongs  90  retained proximate the front end  46  and contact prongs  90  retained proximate the rear end  54 . The contact prongs  90  at the rear end  54  engage electrical traces (not shown) extending along the length of the FFCs  14 . The FFCs  14  extend to an electronic sensor (not shown) that monitors the supply of power. 
     In operation, the electrical connector  10  is connected to a computer application such as a server (not shown) having printed circuit boards in a server cabinet. The server cabinet may contain, by way of example only, a motherboard (not shown) and daughter cards (not shown). The electrical connector  10  receives a daughter card in the card slot  42 . As the daughter card is inserted into the card slot  42 , in the direction of arrow A, the daughter card pushes the oppositely aligned beams  62  of each power contact  58  away from each other along the vertical axis  66  such that (tie beams  62  press firmly against both sides of the daughter card. The daughter card has electrical traces thereon that engage the beams  62  of the power contacts  58  such that electrical power is provided to the daughter card and thus the motherboard through the power wires  18  by the power supply. Likewise, the daughter card pushes the oppositely aligned contact prongs  90  of the top and bottom signal contacts  74  and  78  at the front end  46  away from each other such that the contact prongs  90  press firmly against both sides of the daughter card. The daughter card has electrical traces thereon that engage the contact prongs  90  of the top and bottom signal contacts  74  and  78  such that the electronic sensor monitors the power supply to the motherboard through the FFCs  14 . 
     FIG. 4 illustrates an isometric view of a top signal contact  74  formed according to an embodiment of the present invention. The top signal contact  74  is generally similar to the bottom signal contact  78  (FIG.  1 ). The H-shaped top signal contact  74  is defined by first and second U-shaped portions  240  and  244 . The first U-shaped portion  240  has a top contact leg  94  formed with a bottom retention leg  106 , and the second U-shaped portion  244  has a top retention leg  98  formed with a bottom contact leg  102 . An intermediate bar  110  is formed with, and connects, the first and second U-shaped portions  240  and  244 . The bottom contact leg  102  has a rounded contact prong  90 , and the bottom retention leg  106  has a triangular retention prong  114 . The top retention leg  98  has retention barbs  118 , and the top contact leg  94  has a triangular contact prong  90 . 
     FIG. 2 illustrates a more detailed isometric view of the electrical connector  10 , FFCs  14 , and power wires  18  of FIG.  1 . The H-shaped bottom signal contact  78  likewise is defined by first and second U-shaped portions  248  and  252 . The first U-shaped portions  248  has a bottom contact leg  130  formed with a top retention leg  126 , and the second U-shaped portion  252  has a top contact leg  122  formed with a bottom retention leg  134 . An intermediate bar  138  is formed with, and connects, the first and second U-shaped portions  248  and  252 . The bottom retention leg  134  has retention barbs  118 , and the bottom contact leg  130  has a triangular contact prong  90 . The top contact leg  122  has a rounded contact prong  90 , and the top retention leg  126  has a triangular retention prong  114 . 
     FIG. 5 illustrates a cutaway isometric view of the electrical connector  10 , FFCs  14 , and power wires  18  of FIG.  1 . The top channels  82  are separated from each other by channel walls  84 . The divider wall  38  and a top retention wall  142  extend perpendicularly through the channel walls  84  along a longitudinal axis  146 . The top retention wall  142  defines a retention cavity  150  and a contact cavity  154  within the top channel  82 . The retention cavity  150  receives the top retention leg  98  and the contact cavity  154  receives the bottom contact leg  102  such that the intermediate bar  110  engages the top retention wall  142 . The top contact leg  94  and the bottom retention leg  106  are retained within the top channel  82  between the divider wall  38  and a top wall  158  of the top portion  22 . The top retention wall  142  frictionally engages the retention barbs  118  of the top retention leg  98  when the top signal contact  74  is inserted into the top channel  82  in the direction of arrow B. Thus, the top retention leg  98  retains the top signal contact  74  within the top channel  82 . 
     Likewise, the bottom channels  86  are separated from each other by the channel walls  84 . The divider wall  38  and a bottom retention wall  166  extend perpendicularly through the channel walls  84  along the longitudinal axis  146 . The bottom retention wall  166  defines a retention cavity  170  and a contact cavity  174  within the bottom channel  86 . The retention cavity  170  receives the bottom retention leg  134  and the contact cavity  174  receives the top contact leg  122  such that the intermediate bar  138  engages the bottom retention wall  166 . The top retention leg  126  and the bottom contact leg  130  are retained within the bottom channel  86  between the divider wall  38  and a bottom wall  178  of the bottom portion  263  The bottom retention wall  166  frictionally engages the retention barbs  118  of the bottom retention leg  134  when the bottom signal contact  78  is inserted into the bottom channel  86  in the direction of arrow B. Thus, the bottom retention leg  134  retains the bottom signal contact  78  within the bottom channel  86 . 
     Returning to FIG. 2, each top signal contact  74  in a top channel  82  is aligned with a corresponding bottom signal contact . 78  in a bottom channel  86  such that the contact prongs  90  of the bottom contact leg  102  of the top signal contact  74  and the top contact leg  122  of the bottom signal contact  78  are oppositely aligned along the vertical axis  66 . Similarly, the top contact leg  94  and the bottom retention leg  106  of the top signal contact  74  and the top retention leg  126  and the bottom contact leg  130  of the bottom signal contact  78  are aligned with each other along the vertical axis  66 . 
     The contact prongs  90  of the bottom contact leg  102  and the top contact leg  122  extend toward each other into the card slot  42  proximate the front end  46  of the housing  34  and are separated by a vertical distance D 1  that is less than the thickness of the daughter card. As the daughter card is inserted into the card slot  42 , in the direction of arrow A, the daughter card engages the contact prongs  90  of the vertically aligned bottom, contact leg  102  and top contact leg  122 . Because the daughter card is thicker than the distance D 1 , the daughter card pushes the vertically aligned contact prongs  90  away from each other such that the flexible bottom contact leg  102  of the top signal contact  74  is pushed in the direction of arrow C into the contact cavity  154  of the top channel  82  toward the top retention wall  142  and the flexible top contact leg  122  of the bottom signal contact  78  is pushed in the direction of arrow D into the contact cavity  174  of the bottom channel  86  toward the bottom retention wall  166 . Thus, the contact prongs  90  of the top and bottom contact legs  122  and  102  resistibly engage the top and bottom sides of the daughter card, respectively. 
     The daughter card has electrical traces on each side that are oriented to engage the contact prongs  90  of the top and bottom, contact legs  122  and  102  when the daughter card is inserted into the card slot  42 . The contact prongs  90  of the top contact legs  122  contact the electrical traces on the bottom side of the daughter card and the contact prongs  90  of the bottom contact legs  102  contact the electrical traces on the top side of the daughter card. Thus, the top and bottom signal contacts  74  and  78  are electrically connected to the daughter card. 
     FIG. 3 illustrates an isometric view of the electrical connector  10  with a stuffer  182  removed according to an embodiment of the present invention. In the case of the top signal contact  74 , the contact prong  90  of the top contact leg  94  and the retention prong  114  of the bottom retention leg  106  extend toward each other into the top FFC slot  50  proximate the rear end  54  of the housing  34  and are separated by a vertical distance D 2 . Similarly, in the case of the bottom signal contact  78 , the contact prong  90  of the bottom contact leg  130  and the retention prong  114  of the top retention leg  126  extend toward each other into the bottom FFC slot  52  proximate the rear end  54  of the housing  34  and are separated by the vertical distance D 2  as well. The top FFC slot  50  receives an FFC  14  such that the electrical traces on the FFC  14  engage the contact prongs  90  of the top contact legs  94  of the top signal contacts  74 . The bottom FFC slot  52  receives an FFC  14  such that the electrical traces on the FFC  14  engage the contact prongs  90  of the bottom contact legs  130  of the bottom signal contacts  78 . 
     The electrical connector  10  includes the U-shaped stuffer  182 . The stuffer  182  is insulated and has parallel top and bottom retention walls  186  and  190  formed with a base wall  194 . The top and bottom retention walls  186  and  190  each have a maximum thickness of D 3  that tapers down to a thickness of D 4  at insertion ends  198 . The distance D 2  is greater than the distance D 4  but smaller than the distance D 3 . When an FFC  14  is fully inserted into both the top and bottom FFC slots  50  and  52 , the stuffer  182  is placed in the direction of arrow B such that the top retention wall  186  enters the top FFC slot  50  between an FFC  14  and the retention prong  114  of the bottom retention leg  106  and the bottom retention wall  190  enters the bottom FFC slot  52  between an FFC  14  and the retention prong  114  of the top retention leg  126 . 
     Because the distance D 4  is less than the distance D 2 , the insertion ends  198  of the top and bottom retention walls  186  and  190  initially slide without resistance between the top contact leg  94  and the bottom retention leg  106  of the top signal contact  74  and the top retention leg  126  and the bottom contact leg  130  of the bottom signal contact  78 , respectively. However, as the stuffer  182  gradually slides further in the direction of arrow B, the thickness D 3  of the top retention wall  186  pushes the top contact leg  94  in the direction of arrow C toward the top wall  158  and pushes the bottom retention leg  106  in the direction of arrow D toward the divider wall  38 . Likewise, the thickness D 3  of the bottom retention wall  190  pushes the top retention leg  126  in the direction of arrow C toward the divider wall  38  and pushes the bottom contact leg  130  in the direction of arrow D toward the bottom wall  178 . When the stuffer  182  is fully inserted into the top and bottom FFC slots  50  and  52 , the retention prong  114  of the bottom retention leg  106  of the top signal contact  74  resistibly engages the top retention wall  186  and the retention prong  114  of the top retention leg  126  of the bottom signal contact  78  resistibly engages the bottom retention wall  190 . Thus, an FFC  14  is firmly retained in contact with the contact prongs  90  of the top contact legs  94  of the top signal contacts  74  and an FFC  14  is firmly retained in contact with the contact prongs  90  of the bottom contact legs  130  of the bottom signal contact  78 . 
     The distance D 2  is greater than the thickness of an FFC  14 , thus, an FFC  14  is inserted into the top and bottom FFC slots  50  and  52  with minimal insertion force and no buckling. The FFCs  14  then are secured into contact with the contact prongs  90  of the top contact legs  94  and the contact prongs  90  of the bottom contact legs  130  by placing the stuffer  182  into the top and bottom FFC slots  50  and  52 . 
     Returning to FIG. 2, the stuffer  182  and the FFCs  14  are fully inserted into the top and bottom FFC slots  50  and  52 . The FFCs  14  are positioned within the top and bottom FFC slots  50  and  52  such that the electrical traces on the FFCs  14  are aligned with, and firmly contact, the contact prongs  90  of the top contact legs  94  of the top signal contacts  74  and the contact prongs  90  of the bottom contact legs  130  of the bottom signal contacts  78 . Thus, the top signal contacts  74  arc electrically connected to an FFC  14  and the bottom signal contacts  78  are electrically connected to an FFC  14 . Consequently, the electrical traces on the top side of the daughter card are electrically connected to the electrical traces of an FFC  14  via the top signal contacts  74  and the electrical traces on the bottom side of the daughter card are electrically connected to the electrical traces of an FFC  14  via the bottom signal contacts  78 . The electronic sensor is therefore connected to the motherboard and monitors the power supply of the motherboard. 
     Alternatively, the daughter card may be removed from the card slot  42  in the direction of arrow B such that the daughter card no longer resistibly engages the contact prongs  90  of the bottom contact legs  102  of the top signal contact  74  and the top contact legs  122  of the bottom signal contacts  78 . Thus, the bottom contact legs  102  extend in the direction of arrow D away from the top retention wall  142  to their original unbiased position and the top contact legs  122  extend in direction of arrow C away from the bottom retention wall  166  to their original unbiased position. Likewise, the stuffer  182  may be removed from the top and bottom FFC slots  50  and  52  in the direction of arrow A such that the top retention wall  186  no longer resistibly-engages the contact prongs  90  of the top contact legs  94  and the retention prongs  114  of the bottom retention legs  106  and the bottom retention wall  190  no longer resistibly engages the contact prongs  90  of the bottom contact legs  130  and the retention prongs  114  of the top retention legs  126 . Thus, the top contact legs  94  extend in the direction of arrow D away from the top wall  158  toward their original unbiased position and the bottom retention legs  106  then extend in the direction of arrow C away from the divider wall  38  to their original unbiased position. Likewise, the bottom contact legs  130  extend in the direction of arrow C away from the bottom wall  178  to their original unbiased position and the top retention legs  126  extend in the direction of arrow D away from the divider wall  38  to their original unbiased position. 
     The electrical connector of the various embodiments provides several benefits. First, the top and bottom signal contacts are much thinner than the signal contacts of the prior art. Therefore, the signal contacts have a smaller pitch across the longitudinal axis than the prior art signal contacts, which enables more power signals and power cables to be used with the electrical connector or allows for a smaller electrical connector. Also, the signal contacts are connected to the electronic sensor with an FFC instead of several separate wires. The FFC takes up less space than individual wires. Also, the FFC is easier to connect to the signal contacts then wires because no crimping tool is necessary, and the FFC may be detached from the signal contacts without having to replace the signal contacts. Additionally, the stuffer enables an operator to install the FFC into firm contact with contact prongs with minimal insertion force and no buckling of the FFC. Finally, the signal contacts are easy to install into the housing. 
     While the invention has been described with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.