Patent Publication Number: US-6210190-B1

Title: Compact flexible board connector

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a flexible board connector, and particularly to a compact flexible board connector for retaining a flexible circuit board in electrical connection with the terminals thereof. 
     2. Brief Description of the Prior Art 
     U.S. Pat. No. 5,458,506 discloses a prior art flexible board connector (see FIG. 11) having an elongated pressure member  147  attached to a housing  160  and a plurality of contact elements  135  received in the housing  160 . The pressure member  147  is adapted to rotate around a turning center  145  of a fulcrum portion  137  of the contact element  135  from a closed position to an open position. A pressure edge  152  is provided on the pressure member  147 . When the pressure member  147  is in the closed position, the pressure edge  152  is inside a line including the turning center  145  and a contact portion  140  of the contact element  135  and presses a flexible circuit board F (shown in phantom) against the contact portion  140 . When the pressure member  147  is in the open position, the pressure edge  152  is outside the line and the flexible circuit board F is ready to be extracted. The pressure member  147  is designed to self-retain in the closed position and to apply enough torque to constrain the flexible circuit board. The flexible board connector therefore, requires enough space for the elongated pressure member  147  to rotate therein. What is more, the length of the pressure member  147  must be long enough for operation and retention purposes. The contact elements  135  further require link portions  138  and connection portions  139  for connecting to a printed circuit board (not shown). Thus, further minimization of the width of the connector is limited. 
     U.S. Pat. No. 4,647,131 describes another prior art connector (see FIG. 12) with conductor retention means. The connector has a retaining element which includes a projecting part  213  and a counter element  216 . The projecting part  213  defines a toothed surface  214  on a top end thereof for cooperating with a friction surface  215  on the counter element  216  to fix a flexible circuit board  210  therebetween, whereby the flexible circuit board  210  makes electrical contact with contact surfaces  225 ,  226  of a plurality of terminals  220 . The retaining element further provides a spindle  211  coupled to a lever  217  for swiveling the projecting part  213 . The spindle  211  then rotates in a clockwise direction to swivel the projection part  213  from a position of pressing against the flexible circuit board  210  to a position where the upper contact surface  225  of the terminal  220  is lifted by a protrusion surface  219  of the projecting part  213  to release the flexible circuit board  210 . The toothed surface  214  must be precisely manufactured to securely press on the flexible circuit board  210  without scraping circuit traces on the flexible circuit board  210 . Production cost of the connector is consequently high. 
     Other prior art connectors are disclosed in Taiwan Patent Application Nos. 83102251, 83112042, and 86203032. 
     An improved flexible board connector is required to overcome the disadvantages of the prior art. 
     BRIEF SUMMARY OF THE INVENTION 
     A first object of the present invention is to provide a compact flexible board connector; 
     A second object of the present invention is to provide a compact flexible board connector which is more reliable; and 
     A third object of the present invention is to provide a compact flexible board connector which is easy to assemble. 
     To achieve the above objects, a compact flexible board connector of the present invention comprises a dielectric housing, a plurality of conductive terminals being received in a plurality of receiving passageways of the housing, an elongated cylindrical spindle, and a pressure body enclosing the spindle. The housing has a flat base, a pair of side walls upwardly depending from opposite ends of the base, a beam formed between the side walls and a plurality of receiving passageways defined in a bottom surface of the beam. The side walls each define an opening extending downwardly from a top edge thereof. Each of the openings is flanked by a pair of lead-ins and communicates with a receiving hole for receiving the spindle. A retaining stop is formed on an upper inside corner of each side wall and includes a wedge and a block for retaining the pressure body in a closed position. 
     The pressure body has an oval cross-section and defines a central longitudinal cavity for receiving the spindle. An elongate retention ridge is formed along the length of the outside of the pressure body which is used as a handle to rotate the pressure body about the spindle. The retention ridge is small but adapted for easily operating the pressure body. Furthermore, the retention ridge and the retaining stops fit in the space between the side walls so the connector size is minimized. 
     In assembly, the plurality of terminals is received in the receiving passageways of the housing. The spindle is inserted in the cavity of the pressure body and both ends of the spindle are received in the receiving holes of the housing. The pressure body is placed in an open position where the major axis of the cross-section of the pressure body is nearly parallel to the base. A flexible circuit board is then inserted between the terminals and the pressure body. The retention ridge is subsequently rotated until it clamps between the wedges and the blocks, whereby the pressure body is in a closed position and the major axis is then nearly perpendicular to the base. The flexible circuit board is thereby pressed against the terminals by the pressure body. 
     In an alternative embodiment, the spindle is integrally formed with the housing and extends between the side walls. The pressure body defines a gap through which the spindle is press-fitted into the cavity thereof. The pressure body is adapted for rotating around the spindle from an open position, where a flexible circuit board is permitted to be extracted, to a closed position, where the pressure body presses the flexible circuit board against the terminals. 
     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 a flexible board electrical connector in accordance with a first embodiment of the present invention; 
     FIG. 2 is an assembled view of FIG. 1 in an open position; 
     FIG. 3 is a cross sectional view of the flexible board connector of FIG. 2 taken along the line  3 — 3 ; 
     FIG. 4 is a view similar to FIG. 2, but in an closed position; 
     FIG. 5 is a cross sectional view of the flexible board connector of FIG. 4 taken along the line  5 — 5 ; 
     FIG. 6 is an exploded view of a flexible board electrical connector in accordance with a second embodiment of the present invention; 
     FIG. 7 is an assembled view of FIG. 6 in an open position; 
     FIG. 8 is a cross sectional view of the flexible board connector of FIG. 7 taken along the line  8 — 8 ; 
     FIG. 9 is a view similar to FIG. 7, but in an closed position; 
     FIG. 10 is a cross sectional view of the flexible board connector of FIG. 9 taken along the line  10 — 10 ; 
     FIG. 11 is a cross sectional view of a first prior art flexible board connector; and 
     FIG. 12 is a cross sectional view of another prior art flexible board connector. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 shows a flexible circuit board  40  and a flexible board electrical connector  100  in accordance with a first embodiment of the present invention. The flexible board connector  100  comprises a dielectric housing  10 , a pressure member  30  supported in the housing  10  and a plurality of conductive terminals  20  received in the housing  10 . 
     The housing  10  includes a flat elongated base  11 , a pair of side walls  13  depending upwardly from the base  11 , a beam  12  extending longitudinally along the base  11  between the side walls  13 , and a plurality of receiving passageways  111  defined in a bottom surface of the beam  12  adjacent the base  11 . A pair of upwardly facing openings  131  are defined in top edges of the side walls  13 , each opening  131  flanked by a pair of lead-ins  133  and being in communication with a receiving hole  132 . The side walls  13  each form a retaining stop  18  on upper inside corners thereof. The retaining stop comprises a wedge  14  and a block  15 . The side walls  13  further define a space  19  therebetween. 
     Each right angle terminal  20  has an engaging end  21  on one end, a soldering tail  22  on an opposite end, and a fixing portion  23  between the engaging end  21  and the soldering tail  22 . Each fixing portion  23  includes a right angle bend and forms a barb  230  for interferentially securing the terminals  20  in the receiving passageways  111 . 
     The pressure member  30  includes a cylindrical spindle  32  and an elongated tubular pressure body  31  having an oval cross-section. The pressure body  31  forms a retention ridge  312  along a length thereof for being locked between the wedges  14  and the blocks  15  of the housing  10 . The pressure body  31  also defines a longitudinal central cavity  313  therein for receiving the spindle  32 . The cavity  313  is of a dimension slight greater than that of the spindle  32  and allows the spindle  32  to rotate freely therein. The spindle  32  is of a diameter substantially equal to that of the receiving holes  132  for being secured in the receiving holes  132 . The retention ridge  312  is small but adapted for easily operating the pressure body  31 . Furthermore, the retention ridge  312  and the retaining stops  18  are accommodated in the space  19  of the housing  10  whereby the size of the connector  100  is minimized. 
     Also referring to FIGS. 2 and 3, in assembly, the plurality of terminals  20  is secured in the receiving passageways  111 . The engaging ends  21  of the terminals  20  extend along a top surface of the base  11  for contacting an inserted flexible circuit board  40 . The soldering tails  22  of the terminals  20  downwardly bend to fix into a printed circuit board (not shown). The spindle  32  is received in the cavity  313  of the pressure body  31  and is press-fitted through the lead-ins  133  into the receiving holes  132  of the housing  10 . The spindle  32  is also adapted to be retracted from the receiving holes  132 . The flexible circuit board  40  is then inserted between the pressure body  31  and the engaging ends  21  of the terminals  20 . The pressure body  31  is initially in an open position where the major axis of the oval cross-section thereof is substantially parallel to the base  11  (see FIG.  3 ). The retention ridge  312  is distant from the wedges  14  and the blocks  15  and the pressure body  31  does not press against the flexible circuit board  40 . 
     Referring to FIGS. 4 and 5, when the pressure body  31  pivots about the spindle  32  from the open position to a closed position, the retention ridge  312  then locks between the wedges  14  and the blocks  15  whereby the major axis of the pressure body  31  will be in a position perpendicular to the base  11 . Therefore, the pressure body  31  will press against the flexible circuit board  40  securing it in position and establishing a stable electrical connection between the engaging ends  21  of the terminals  20  and the circuit traces on the flexible circuit board  40 . 
     FIG. 6 shows a flexible board connector  100 ′ in accordance with a second embodiment of the present invention. The flexible board connector  100 ′ includes an insulative housing  10 ′, a plurality of terminals  20 ′ each having an interfering barb  230 ′, and a pressure body  31 ′. 
     The housing  10 ′ has a flat base  11 ′, a pair of side walls  13 ′ upwardly depending from opposite ends of the base  11 ′ and a beam  12 ′ lying between the side walls  13 ′ on the base  11 ′. The housing  10 ′ further includes a cylindrical spindle  32 ′ which is integrally formed with the housing  10 ′ and extends between the side walls  13 ′. The beam  12 ′ defines a plurality of receiving passageways  111 ′ therethrough (FIGS. 8 and 10) to a rear surface thereof. Each of the side walls  13 ′ forms a retaining stop  18 ′ comprising a wedge  14 ′ and a block  15 ′. Both wedges  14 ′ and blocks  15 ′ are provided on upper inside corners of the side walls  13 ′. 
     The elongated tubular pressure body  31 ′ has an oval cross-section. The pressure body  31 ′ defines a longitudinal central cavity  313 ′ for receiving the spindle  32 ′ and forms a retention ridge  312 ′ outwardly depending therefrom. The retention ridge  312 ′ is configured along the length of the pressure body  31 ′ at a position between the major and minor axis of the oval cross-section of the pressure body  31 ′. The pressure body  31 ′ further defines a gap  311 ′ running the length of the pressure body  31 ′ proximate a minor axis of the oval cross-section thereof. 
     Referring to FIGS. 7 to  10 , in assembly, the plurality of terminals  20 ′ is received in the receiving passageways  111 ′, the interfering barbs  230 ′ thereof securely engaging with the receiving passageways  111 ′. The engaging ends  21 ′ of the terminals  20 ′ extend along a top surface of the base  11 ′ for contacting a flexible circuit board  40 ′. The soldering tails  22 ′ of the terminals  20 ′ are downwardly bent to fit into a printed circuit board (not shown). The spindle  32 ′ is press-fitted into the cavity  313 ′ of the pressure body  31 ′ through the gap  311 ′. The pressure body  31 ′ is adapted to be extractable from the housing  10 ′ by disengaging the spindle  32 ′ from the cavity  313 ′ of the pressure body  31 ′ through the gap  311 ′. 
     The pressure body  31 ′ is rotatable from an open position to a closed position by using the retention ridge  312 ′ as a handle. When the pressure body  31 ′ is in the open position (FIG. 8) where the major axis of the oval cross-section is nearly parallel to the base  11 ′, the retention ridge  312 ′ is distant from the retaining stops  18 ′ and the flexible circuit board  40 ′ is permitted to be inserted between the pressure body  31 ′ and the engaging ends  21 ′ of the terminals  20 ′. The pressure body  31 ′ pivots about the spindle  32 ′ from the open position to the closed position where the major axis is nearly perpendicular to the base  11 ′, and the retention ridge  312 ′ is then fixed between the wedges  14 ′ and the blocks  15 ′ of the side walls  13 ′. Therefore, the pressure body  31 ′ in the closed position (FIG. 10) presses the flexible circuit board  40 ′ against the engaging ends  21 ′ of the terminals  20 ′ providing a stable electrical connection between the contacts  20 ′ and the circuit traces on the flexible circuit board  40 ′. 
     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.