Abstract:
An electrical connector includes an electrically insulative body and a conductive shield. The electrically insulative body has a plurality of terminals. Each terminal has a tail respectively clamped on a circuit board. The electrically insulative body has two backwardly extended locating blocks at two sides. Each locating block has a locating groove which receives the circuit board upon connection of the terminals to the respective contacts of the circuit board. The locating blocks also include flexible arms with upright portions adapted for engaging into respective retaining apertures on the circuit board. The conductive shield includes backwardly extended grounding arms which also include retainers adapted for engaging into respective apertures on the circuit board. The retainers and retaining apertures secure the connector to the circuit board against vertical as well as forward-backward/leftwards-rightwards horizontal displacement.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to an electrical connector and, more particularly, to an improved structure for a straddle mount electrical connector, which is stably secured to the circuit board before as well as after the tails of the terminals have been affixed to circuit traces on the circuit board by way of a surface mounting technique (SMT), such as by soldering.  
         BACKGROUND OF THE INVENTION  
         [0002]    [0002]FIG. 1 is a perspective view of a prior art straddle mount electrical connector  1  relative to a circuit board  2 . The connector  1  comprises an electrically insulative body  10 , and two vertically spaced rows of terminals  100  provided in the electrically insulative body  10 . Each terminal  100  has a rear clamping tail  101 . The clamping tails  101  of the terminals  100  are respectively clamped on top and bottom sidewalls of the circuit board  2  and forced into contact with respective contacts (not shown) at the circuit board  2 , and then a SMT is employed to mechanically and electrically connect the connector  1  to the circuit board  2 .  
           [0003]    Because the clamping tails  101  of the terminals  100  are respectively clamped on top and bottom sidewalls of the circuit board  2 , the clamping tails  101  only prohibit vertical displacement between the connector  1  and the circuit board  2 . There is only small frictional resistance between the connector  1  and the circuit board  2  in forward-backward and leftwards-rightwards horizontal directions. Therefore, during SMT operation, possible forward-backward or leftwards-rightwards vibration cannot be eliminated, resulting in inaccurate contact between the clamping tails  101  and the respective contacts at the circuit board, or tilting/deformation of the terminals  100 . In this case, SMT operation may not be workable, and a defective product may be produced. If the terminals  100  are all welded to the circuit board  2  by SMT operation, improper application of force during a plug and pull action or frequent plug and pull action may cause the terminals  100  of the connector  1  to displace. Therefore, the yielding rate cannot be greatly improved according to this conventional design.  
           [0004]    Further, the design cannot prevent the connection of the connector  1  to the circuit board  2  in a wrong direction. This problem happens easily during a high-speed mass production operations. If the connector is connected to the circuit board in a wrong direction, the terminals  100  cannot be accurately connected to the respective contacts, and the product becomes useless. This problem must be eliminated.  
           [0005]    The present invention provides an electrical connector which overcomes the problems presented in the prior art and which provides additional advantages over the prior art, such advantages will become clear upon a reading of the attached specification in combination with a study of the drawings.  
         OBJECTIVES AND SUMMARY OF THE INVENTION  
         [0006]    A general object of the present invention to provide an electrical connector which can be stably and accurately fastened to the circuit board, preventing displacement in vertical direction as well as in the forward-backward and leftward-rightward horizontal directions.  
           [0007]    Another object of the present invention is to provide an electrical connector which provides accurate contact between clamping tails of the electrical connector and the respective contacts on a circuit board.  
           [0008]    A further object of the present invention is to provide an electrical connector which eliminates tilting/deformation of the terminals of the connector.  
           [0009]    Another object of the present invention is to provide an electrical connector which is unable to be connected with the circuit board in the wrong direction.  
           [0010]    Briefly, and in accordance with the foregoing, the present invention discloses an improved electrical connector. The electrical connector includes an electrically insulative body and a conductive shield. The body has two backwardly extended locating blocks at two sides. Each locating block has a locating groove which receives the circuit board upon connection of the terminals to the respective contacts of the circuit board. Each locating block further includes a flexible arm with an upright portion for engaging into a respective retaining aperture on the circuit board. The conductive shield includes two backwardly extending grounding arms. Each grounding arm has a retainer adapted for engaging into a respective retaining aperture of the circuit board.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    [0011]FIG. 1 is a perspective view of a prior art straddle mount electrical connector and a perspective view of a circuit board;  
         [0012]    [0012]FIG. 2 is an exploded perspective view of an electrical connector which incorporates the features of a first embodiment of the present invention, and a perspective view of a circuit board;  
         [0013]    [0013]FIG. 3 is a fragmentary perspective view of a portion of the grounding arm of the electrical connector of FIG. 2;  
         [0014]    [0014]FIG. 4 is perspective view showing the electrical connector of the first embodiment of the present invention assembled with the circuit board, which is shown in perspective;  
         [0015]    [0015]FIG. 5 is a cross-sectional view of a portion of the first embodiment of the electrical connector and the circuit board, with the portion of the connector attached to the circuit board;  
         [0016]    [0016]FIG. 6 is a fragmentary perspective view of a grounding arm which incorporates features of a second embodiment of the present invention;  
         [0017]    [0017]FIG. 7 is an exploded perspective view of an electrical connector which incorporates the features of a third embodiment of the present invention and a perspective view of a circuit board;  
         [0018]    [0018]FIG. 8 is a fragmentary perspective view of a flexible arm and locating block of the electrical connector of FIG. 7;  
         [0019]    [0019]FIG. 9 is a perspective view showing the electrical connector of the third embodiment of the present invention assembled with the circuit board, which is shown in perspective; and  
         [0020]    [0020]FIG. 10 is a cross-sectional view of a portion of the third embodiment of the electrical connector and the circuit board, with the portion of the electrical connector attached to the circuit board.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0021]    While the invention may be susceptible to embodiment in different forms, there is shown in the drawings, and herein will be described in detail, specific embodiments with the understanding that the present disclosure is to be considered an exemplification of the principles of the invention, and is not intended to limit the invention to that as illustrated and described herein.  
         [0022]    A first embodiment of the electrical connector  3  of the present invention is shown in FIGS.  2 - 5 . The connector  3  includes an electrically insulative body  30 , and a conductive shield  31  which covers a portion of the electrically insulative body  30 .  
         [0023]    The electrically insulative body  30  is a molded one-piece component composed of a dielectric material such as plastic or the like. The electrically insulative body  30  has a backside  30   a  and a front side  30   b.  A generally rectangular shaped portion  37  is centrally located and extends from the front side  30   b  of the insulative body  30 . The insulative body  30  is provided with two rows of terminals  300  which extend through the body  30  and which are centrally located and extend from the back side  30   a  of the insulative body  30 . Each terminal  300  has a rear clamping tail  301  adapted for clamping on a respective contact of a circuit board  4 . The clamping tails  301  of the upper row of terminals  300  mate with the contacts (not shown) on the top side of the circuit board  4  and the clamping tails  301  of the lower row of terminals  300  mate with the contacts (not shown) on the bottom side of the circuit board  4 .  
         [0024]    The electrically insulative body  30  also includes two locating blocks  32  bilaterally disposed at the back side  30   a  thereof. Each locating block  32  includes a pair of upper arms  32   a  and a pair of lower arms  32   b  which extend parallel to the terminals  300 . The upper arms  32   a  are spaced apart from each other. The lower arms  32   b  are spaced apart from each other. An elongated groove  320  is positioned between the upper arms  32   a  and the lower arms  32   b  and also extends parallel to the terminals  300 . The groove  320  is used to assist in the positioning of the circuit board  4  as discussed herein.  
         [0025]    The insulative body  30  further includes base portions  34  provided on each end thereof. Each base portion  34  includes a first shoulder  35   a  and a second shoulder  35   b.  The first shoulder  35   a  and the second shoulder  35   b  extend rearwardly from the backside  30   a  of the base portion  34 . A passageway (not shown) is provided between the first shoulder  35   a  and the second shoulder  35   b.  Each base portion  34  also includes a recess  38  and an aperture  52  below each recess  38  and above the second shoulder  35   b.  The recess  38  defines a shoulder  38   a  on the front side of the base portion  34 .  
         [0026]    A lead-in rod  33  is provided on one of the base portions  34  of the insulative body  30 . The lead-in rod  33  extends rearwardly from the base portion  34  parallel to the locating block  32 . The lead-in rod  33  is aligned vertically with the groove  320 .  
         [0027]    The conductive shield  31  includes a plate  36  having a first side  36   a , a second side  36   b , a first end  50   a , and an opposite second end  50   b . A generally rectangular skirt  39  depends from the second side  36   b  of the plate  36 . Two bilaterally suspended grounding arms  310  extend from the first side  36   a  of the plate  36  for welding to respective grounding contacts (not shown) at the bottom side of the circuit board  4 . One grounding arm  310  is positioned near the first end  50   a  of the plate  36  and a second grounding arm  310  is positioned near the second end  50   b  of the plate  36 . Each grounding arm  310  has an upwardly protruding retainer  311  positioned near the free end  310   a  of the grounding arm  310 . In FIGS. 2 and 3, the retainer  311  is a protruded hook formed by stamping. One end of the retainer  311  is connected to the respective grounding arm  310  and leads to a ramped surface  311   a.  The ramped surfaced  311   a  leads to a horizontal surface  311   b  which terminates in a smoothly arched face  312  suspended in the open air at the opposite end of the retainer  311 . In a second embodiment, shown in FIG. 6, the retainer  315  is shaped like a semispherical shell protruded from the top of the grounding arm  316 . The retainer  315  includes a ramped surface  317  which leads to a vertical end wall  318 .  
         [0028]    Two tabs  51  are located near the top of the conductive shield  31  and are spaced from either end  50   a ,  50   b  of the conductive shield  31 . Cylindrically shaped protrusions  53  are positioned below the tabs  51 . The tabs  51  and protrusions  53  are used to secure the conductive shield  31  to the insulative body  30 .  
         [0029]    When connecting the insulative body  30  to the conductive shield  31 , the skirt  39  of the conductive shield  31  is placed around the portion  37  of the insulative body  30  and the front side  36   a  of the plate  36  sits adjacent to the backside  30   b  of the insulative body  30 . Tabs  51  are bent over the shoulder  38   a  and the protrusions  53  are inserted into the apertures  52 . The grounding arms  310  pass through the passageways (not shown) located on the base portion, preferably between the first shoulder  35  and the second shoulder  36 .  
         [0030]    The circuit board  4  to which the connector  3  is electrically connected includes two retaining apertures  40  and a lead-in slot  42  located near the forward, or leading, edge of the circuit board  4 . The retaining apertures  40  correspond to the retainer  311  of each grounding arm  310  of the conductive shield  31 . The lead-in slot  42  corresponds to the lead-in rod  33  of the insulative body  30 . Therefore, the connector  3  can be clamped on the circuit board  4  only when aiming the connector  3  at the circuit board  4  in the correct direction for enabling the lead-in rod  33  to be inserted into the lead-in slot  42 , as shown in FIG. 4. If the connector  3  is not attached to the circuit board  4  in the correct direction, the lead-in rod  33  will be stopped at the edge of the circuit board  4 , and prohibited from being connected to the circuit board  4 . Therefore, the connector  3  can easily and accurately be installed in the circuit board  4  without causing a vibration.  
         [0031]    When mechanically and electrically connecting the connector  3  to the circuit board  4 , the circuit board  4  is inserted into the groove  320  of each locating block  32  of the electrically insulative body  30  and lead-in rod  33  is inserted into the lead-in slot  42 . The circuit board  4  is inserted between the tails  301  of the upper row of terminals and the tails  301  of the lower row of terminals. As the circuit board  4  is moved into the groove  320  the ramped surface  311  a of the retainer  311  slides along the edge of the retaining aperture  40 . Once the circuit board  4  is moved all the way into the groove  320  the horizontal surface  311   b  is forced within the retaining aperture  40  and the arched face  312  rests against the wall of the retaining aperture  40 , as shown in FIGS. 4 and 5. In the second embodiment, as the circuit board  4  is moved into the groove  320  the ramped surface  317  of the retainer  315  slides along the edge of the retaining aperture  40 . Once the circuit board  4  is moved all the way into the groove  320  the vertical wall  318  is forced into the retaining aperture  40 . By means of the clamping and retaining effect of the clamping tails  301  of the terminals  300 , the locating groove  320  of each locating block  32  of the electrically insulative body  30  and the retainer  311  of each grounding arm  310  of the conductive shield  31 , the connector  3  is stably positioned on the circuit board  4  and, the terminals  300  are accurately maintained in contact with the respective contacts at the circuit board  4  for easy application of SMT operation. After SMT operation, the connection of the connector  3  to the circuit board  4  is strong enough to resist against push and pull force in all directions.  
         [0032]    A third embodiment of the electrical connector  3 ′ of the present invention is shown in FIGS.  7 - 10 . The third embodiment of the electrical connector  3 ′ is identical to the first embodiment of the electrical connector  3  except that a flexible suspended arm  321  is disposed in the respective locating groove  320 . Accordingly, like elements are denoted by like reference numerals but with a prime after the reference numerals. It is to be understood that the retainer  315  shown in FIG. 6 can be used instead of the retainer  311 .  
         [0033]    The flexible arm  321  includes an elongated portion  323  which is cantilevered from the locating block  32 ′ and extends between the upper arms  32   a ′ and the lower arms  32   b ′ and an upright portion  322  at the free end of the elongated portion  323  adapted for fastening to a respective retaining aperture  41  on the circuit board  5 . The free end of the flexible arm  321  is capable of movement in the vertical direction. As the circuit board  5  is moved into the groove  320 ′, the upright portion  322  will contact the bottom surface of the circuit board  5  and the flexible arm  321  will be forced downward. When the upright portion  322  becomes aligned with the respective retaining aperture  41 , the upright portion  322  will flex or spring upward into the retaining aperture  41 . After engagement of the circuit board  5  into the locating groove  320 ′ of each locating block  32 ′ of the electrically insulative body  30 ′, the terminals  300 ′ are respectively clamped on the circuit board  5 , the retainers  311 ′ of the grounding arms  310 ′ of the conductive shield  31 ′ are respectively engaged into the retaining apertures  40 ′ of the circuit board  5 , and the upright portions  322  of the flexible arms  321  of the electrically insulative body  30 ′ are respectively engaged into the retaining apertures  41  of the circuit board  5 , as shown in FIGS. 9 and 10, and therefore the connector  3  is stably secured to the circuit board  5 .  
         [0034]    As indicated above, the invention provides an electrical connector  3 ,  3 ′ that can be accurately and stably secured to a circuit board before as well as after the application of SMT operation. The electrical connector  3 ,  3 ′ functions smoothly to provide all of the features discussed earlier.  
         [0035]    Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.