Patent Publication Number: US-6210209-B1

Title: Electrical connector for FPC

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an electrical connector and particularly to an electrical connector for connecting a flexible printed circuit board (FPC) with a complementary connector and in turn to a circuit board. 
     2. Description of the Prior Art 
     Electrical connectors are normally used to aid in connecting a FPC to a conventional circuit board. One example of the related art is disclosed in U.S. Pat. No. 5,458,506. As is shown in FIG. 4, a conventional connector for a FPC comprises an insulative housing  5 , a plurality of electrical terminals  6  mounted in the housing  5 , and a rotatable cover plate  7  mounted at a fulcrum portion  8  of the terminal  6  facing an open space above the terminals  6 . While the cover plate  7  is in the open position as shown in phantom in FIG. 4, the FPC  9  is inserted into a cavity  10  of the housing  5  between the terminals  6  and the cover plate  7  at a zero insertion force. Then the cover plate  7  is turned clockwise around the fulcrum portion  8  through an angle of nearly 90° to a closed position and a pressure edge  71  at the lower surface thereof directly presses the FPC  9  to the electrical terminals  6 . 
     The FPC  9  can be electrically connected with the connector in the way described above, but the pressure exerted on the FPC  9  by the cover plate  7  is applied to the terminals  6  directly. The terminals  6  may be permanently deformed by use, resulting in decreased resilience and an increase in the gap between the terminals  6  and the cover plate  7  which in turn can result in unstable signal transmission and unstable retention of the FPC  9  in the housing  5 . Furthermore, the cover plate  7  is loose when in an open position and can readily cause deformation or damage to the housing  5  if acted upon by an unintentional external force or vibration. Lastly the connector occupies a relative large area of precious space in a computer, which runs counter to the present trend toward miniaturization and integration of computer elements. 
     SUMMARY OF THE INVENTION 
     The main object of the present invention is to provide an electrical connector for connecting a FPC with a board-mounted connector such as a board to board connector and resolving the above mentioned problems of the prior art. 
     An electrical connector in accordance with the present invention comprises a dielectric housing, a plurality of generally U-shaped electrical contacts disposed in the housing, and a stuffer mountable to the housing. 
     The dielectric housing defines a receptacle portion on one side for receiving a FPC and a plug portion on an opposite side for mating with the board-mounted connector. The receptacle portion of the housing defines an elongated channel and the plug portion has a pair of grooves and a central portion separating the two grooves. The central portion of the plug portion defines a contact retention structure comprising a plurality of passages in opposite sides thereof and a plurality of supporting posts separating opposite passages. The plug portion of the housing has a pair of engaging members projecting from lateral end walls thereof. 
     Each U-shaped contact laterally straddles one of the supporting posts and is retained by the contact retention structure of the central portion to positively engage with a corresponding terminal of the board-mounted connector. Each contact comprises a curved contacting finger extending into the elongated channel of the receptacle portion. 
     The stuffer comprises a pressing portion and an engaging portion depending from and perpendicular to the pressing portion. The engaging portion has a main body and a pair of arms relatively longer than the main body to adjustably engage with the engaging member of the housing thereby adjusting the relative position of the stuffer and the housing. The main body of the engaging portion presses the FPC, which is inserted between the main body and a mating wall of the elongated channel, against the curved contacting fingers of the electrical contacts situated close to the mating wall. The distal edge of the main body of the engaging portion and the bottom corner of the channel of the housing form ramps complementary with each other. 
     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 assembly of the present invention; 
     FIG. 2 is a sectional view taken from line  2 — 2  of FIG. 1; 
     FIG. 3 is a perspective sectional view of an electrical connector of the present invention; and 
     FIG. 4 is a sectional view of a conventional connector with its cover engaging portion turned to the closed position. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIGS. 1 to  3 , an electrical connector  2  according to the present invention is designed for connecting a flexible printed circuit board (FPC)  3  to a board-mounted connector  1 . 
     The electrical connector  2  includes a dielectric housing  20 , a plurality of generally U-shaped contacts  23  mounted in the insulative housing  20 , and a stuffer  4  insertable into the housing  20 . 
     The housing  20  comprises a plug portion  21  at a lower end thereof and a receptacle portion  22  at an upper end thereof, which is not as wide as the plug portion  21 . 
     The plug portion  21  includes two lateral end walls  212  having a pair of engaging members  25  projecting therefrom and defining a cutout  251  in a center portion thereof, and two longitudinal side walls  211  defining two pairs of apertures  24  at opposite ends thereof. The plug portion  21  has a central portion  213  and a pair of grooves  214  between the central portion  213  and the longitudinal side walls  211  thereof. The central portion  213  defines a contact retention structure comprising a plurality of passages  215  defined in opposite longitudinal sides thereof and a plurality of supporting posts  216  separating the passages  215  in the opposite sides thereof. Neighboring passages  215  in the same side share a bottom portion  217  and an outer side portion  201 . Each supporting post  216  is substantially shorter than a bottom of the central portion  213 . The grooves  214  each define a mating ramped face  230  at an outer corner thereof (see FIG.  2 ). 
     The receptacle portion  22  defines an elongated channel  221  therein and the channel  221  defines a mounting surface  219  and an opposite mating surface  220 . An inclined surface  218  is formed between the mounting surface  219  and a bottom surface (unlabelled) of the channel  221 . A plurality of through holes  202  (see FIG. 3) in communication with one groove  214  of the plug portion are defined in the bottom surface (unlabelled) of the channel  221 . 
     The contacts  23  each comprise a U-shaped portion  231  and a curved contacting finger  232 . The U-shaped portion  231  includes a pair of retaining portions  235  and an intermediate portion  234  connecting the retaining portions  235 . A pair of barbs  233  is formed on either side of each retaining portion  235 . Another inventive feature of the present invention is that its unique U-shaped contacts  23  are fabricated so that the connection between each contact  23  and its carrier strip is at a V-shaped cut on the particular surface denoted by  236  in FIG. 3, which is on the rear face of a barb  233 . 
     The stuffer  4  comprises a pressing portion  41  including an opening (unlabelled) on one edge thereof and an engaging portion  40  depending from and perpendicular to the pressing portion  41 . The engaging portion  40  comprises a main body  43  and a pair of arms  42 . The arms  42  are relatively longer than the main body  43  and each comprises a pair of stepped blocks  421  thereon. Two gaps  401  are defined between lower sections of the main body  43  and the arms  42 . The main body  43  of the engaging portion  40  defines a ramped edge  424  at a lower edge thereof. 
     The board-mounted connector  1  comprises an insulative housing  11  and a plurality of electrical terminals  13 . The housing  11  forms two longitudinal side walls  10  each defining a plurality of passageways  12  therein, the plurality of terminals  13  being accommodated in the passageways  12 . Each side wall  10  forms a pair of tabs  111  at opposite ends thereof and defines a sloping surface  14  at a top end thereof. 
     In assembly, the retaining portions  235  of the contacts  23  interferentially fit into the corresponding passages  215  and are confined by the outer side portions  201  of the passages  215 . The curved contacting fingers  232  of the contacts  23  extend through corresponding through holes  202  into the channel  221  of the receptacle portion  22  and are situated close to the mating surface  220  of the channel  221 . The U-shaped portions  231  of the contacts  23  laterally straddle the associated supporting posts  216  of the central portion  213  of the plug portion  21 . The arms  42  of the stuffer  4  are inserted between the lateral end walls  212  and the engaging member  25 , the stepped blocks  421  of the arms  42  adjustably engaging with the cutouts  251  and the engaging portion  40  partially entering into the channel  221 . The longitudinal side walls  10  of the board-mounted connector  1  are inserted into the grooves  214  of the plug portion  21  of the connector  2 . Each terminal  13  in corresponding passageway  12  of the board-mounted connector  1  engages with one retaining portion  235  of each contact  23  at one end thereof and is mounted to a circuit board (not shown) at the other end thereof. The mating ramped faces  230  of the grooves  214  of the plug portion  21  mate with the sloping surfaces  14  of the board-mounted connector  1  and the tabs  111  lock with the apertures  24 , thereby providing a reliable retention between the connectors  1  and  2 . 
     In use, the FPC  3  is inserted through the opening (unlabelled) of the pressing portion  41  into the channel  221 . A user presses downward on the pressing portion  41  and the ramped edge  424  of the engaging portion  40  cooperates with the inclined surface  218  to move the main body  43  to press the FPC  3  against the curved contact fingers  232  of the contacts  23  while the gaps  401  receive the lateral end walls  212  and the stepped blocks  421  engage with the cutouts  251  for adjusting the engaging force between the FPC  3  and the curved contacting finger  232 . 
     The contacts  23  are reliably retained by the contact retention structure of the central portion  213  of the plug portion  21 . The force applied by the stuffer  4  to the FPC  3  is transferred by the contacts  23  to the mating surface  220 , so the contacts  23  are not deformed even after a long-term period and maintain their resiliency. While not in operation, the stuffer  4  is fixed in the connector  2  by adjustably engaging the arms  42  and the engaging member  25 , thereby avoiding damage to the housing  20  by the stuffer  4 . 
     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.