Abstract:
An electrical connector ( 100 ) for insertion of a daughter printed circuit board (PCB) ( 200 ) includes an insulative housing ( 10 ), a number of terminals ( 20 ) received in the housing, and a sliding guide ( 30 ) movably retained in the insulative housing. The insulative housing defines a receiving slot ( 11 ) for receiving the sliding guide. Each terminal includes a contacting portion ( 22 ) for connecting with the daughter PCB. The daughter PCB is inserted into a receiving recess ( 34 ) defined in the sliding guide and pushes the sliding guide forwardly for driving the terminal to engage/disengage with the daughter PCB.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an electrical connector, and particular to a low insertion force electrical connector. 
     2. Description of Related Art 
     U.S. Pat. No. 4,514,030 discloses an edge card connector in FIGS. 4A-4C thereof having an insulative housing ( 10 ) and six pairs of opposite contacts ( 28 ,  30 ) retained in the insulative housing ( 10 ). The insulative housing ( 10 ) defines a slot ( 24 ) for receiving an inserted PCB ( 26 ) and six pairs of recesses ( 32 ,  34 ). Each of the terminals ( 28 ,  30 ) includes a free end portion ( 40 ), a projecting portion ( 42 ) and an outer end portion ( 36 ) connecting the free end portion ( 40 ) and the projecting portion ( 42 ). Each of the contacts ( 28 ,  30 ) is received in a corresponding recess ( 32 ,  34 ) with the free end portion ( 40 ) and the projection portion ( 42 ) projecting into the slot ( 24 ) for contacting with the inserted PCB ( 26 ). 
     However, if the contacts ( 28 ,  30 ) are made of materials with excellent rigidity, the insertion of the PCB ( 26 ) becomes difficult and the large mating force derived from excellent rigidity will damage contact pads on the inserted PCB ( 26 ). On the contrary, if the contact portions do not have good rigidity, after a period of use, the resiliency of the contacts ( 28 ,  30 ) will decrease so that the free end portion ( 40 ) and the projecting portion ( 42 ) cannot securely engage with the inserted PCB ( 26 ). 
     Hence, an electrical connector capable of providing reliable contact with an inserted PCB but will not damage the contact pads on the PCB is desired. 
     SUMMARY OF THE INVENTION 
     Accordingly, the object of the present invention is to provide an electrical connector having a movable sliding guide for actuating conductive terminals thereof to connect a printed circuit board inserted thereto in a low insertion force. 
     In order to achieve the object set forth, an electrical connector comprises an insulative housing, a sliding guide movably received in the housing, a plurality of terminals retained in the insulative housing, and a movable latching device assembled to the housing. The sliding guide defines a receiving recess in a center thereof for insertion of a daughter PCB, a plurality of receiving channels communicating with the receiving recess. Each of the terminals includes an inclined arm and a contacting portion at a free end of the inclined arm. When the daughter PCB is not fully inserted into the receiving recess, contact pads of the daughter PCB are not connected with the contacting portions. When the daughter PCB is fully inserted into the receiving recess, the daughter PCB pushes the sliding guide forwardly and the sliding guide presses against the inclined arms of the terminals so that the contacting portions move inwardly to electrically connect with the contact pads of the daughter PCB. 
    
    
     Other objects, advantages and novel features of the invention will become more apparent from the following detailed description of the preferred embodiment when taken in conjunction with the accompanying drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of an electrical connector of the present invention and a daughter PCB; and 
     FIGS. 2A-2C are cross-sectional views of continuous inserting processes of the daughter PCB into the electrical connector. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference will now be made to the drawing figures to describe the present invention in detail. 
     Referring to FIG. 1, a low insertion force electrical connector  100  of the present invention mountable on a mother PCB (not shown) is provided for electrically engaging with an inserted daughter PCB  200  thereby establishing an electrical connection between the daughter PCB  200  and the mother PCB. 
     The electrical connector  100  includes a rectangular insulative housing  10 , a plurality of upper and lower terminals  20  received in the insulative housing  10 , a sliding guide  30  movably received in the insulative housing  10  and a latching device (not labeled) for control the movement of the sliding guide  30  in the housing  10 . 
     The insulative housing  10  has a top surface  10   b , a mating surface  10   a  perpendicular to the top surface  10   b  and a bottom mounting surface  10   c  parallel to the top surface  10   b . The insulative housing  10  includes a rectangular receiving slot  11  at the mating surface  10   a  thereof, and two pairs of guiding ribs  12  protruding into the receiving slot  11  from an upper and a bottom peripheral walls of the receiving slot  11 . In addition, the insulative housing  10  defines a pair of top recesses  15  at the top surface  10   b  thereof which are isolated from each other by a projection  16  thereof. Furthermore, a pair of posts  18  extends downwardly from the bottom mounting surface  10   c  for inserting into holes of the mother PCB to pre-retain the connector  100  onto the mother PCB. A position pillar  16   a  extends upwardly from the projection  16  for positioning a spring  17 . It should be noted that the length of the position pillar  16   a  is shorter than the free length of the spring  17 . 
     The sliding guide  30  includes a central receiving recess  34  and two pairs of semicircle guide slots  32  at an upper and a lower outer surfaces thereof for slidably receiving the respective guiding ribs  12 . In addition, the sliding guide  30  forms a plurality of opposite upper and lower ribs  36 . Every two adjacent upper or lower ribs  36  define a receiving channel  36   a . Furthermore, a wedge  37  is formed at a front portion of the upper surface of the sliding guide  30 . 
     Each of the terminals  20  includes a retaining portion  23  for securely retaining the terminal  20  in the insulative housing  10 , an inclined arm  24  extending forwardly from a top end of the retaining portion  23 , an arc contacting portion  22  at a free end of the inclined arm  24  and a horizontal soldering portion  26  extending from a bottom end of the retaining portion  23  out of insulative housing  10  for being soldered onto respective solder pads of the mother PCB (not labeled). The arc contacting portions  22  of the upper and lower terminals  20  extend closer to each other. 
     Referring to FIG. 2A, the latching device includes a first stopper  19  integrally formed with the insulative housing  10  on a top surface of the receiving slot  11 , a plastic snap latch  40  assembled to the top surface  10   b  of the insulative housing  10 , a second stopper  46 , a connecting member  48  connecting the plastic snap latch  40  with the second stopper  46 , a pivot post  14  integrally formed with the insulative housing  10  and the locking wedge  37  formed at the upper outer surface of the sliding guide  30 . The pivot post  14  has a semicircular header  14   a  at a top end thereof to which the plastic snap latch  40  is pivotably assembled. The plastic snap latch  40  includes a folk  40   a  extending downwardly from a front end thereof to connect the connecting member  48  and a handle  44  at a rear end thereof for manually operating the snap latch  40  to drive the second stopper  46  upwardly and downwardly thereby permitting or stopping the movement of the sliding guide  30 . The handle  44  defines a recess  44   a  at a bottom face thereof for receiving the spring  17  and the position pillar  16   a.    
     Referring to FIGS. 2A-2C, when the electrical connector  100  is at an open state, the wedge  37  is located between the first and second stopper  19 ,  46  and the arc contacting portions  22  of the upper and lower terminals  20  defines a first gap therebetween which is larger than the thickness of the daughter PCB  200 . The first stopper  13  engages with the wedge  37  to prevent the sliding guide  30  from moving out of the receiving slot  11 . The daughter PCB  200  is inserted into the receiving recess  34  of the sliding guide  30  with Zero Insertion Force (ZIF) and pushes the sliding guide  30  further into the insulative housing  10  until an inclined surfaces  36   b  of the slide guide  30  abut against the inclined arms  24  of the upper and lower terminals  20 . When the sliding guide  30  is further pushed by the daughter PCB  200  into the insulative housing  10 , the inclined surfaces  36   b  further force the inclined arms  24  to clamp the daughter PCB  200  until the wedge  37  passes through the second stopper  46 . When the wedge  37  passes through the second stopper  46 , the wedge  37  may force the second stopper  46  to move upwardly or the second stopper  46  is pulled by the connecting member  48  by pushing the handle  44 . Successively, the second stopper  46  moves downwardly and engages with the wedge  37  so as to remain a secured electrical connection between the contacting portions  22  and the daughter PCB  200 . 
     When the daughter PCB  200  is to be pulled out from the electrical connector  100 , the handle  44  of the plastic snap latch  40  is pressed to lift the second stopper  46  to disengage with the wedge  37  of the sliding guide  30 . The sliding guide  30  is pushed rearwardly because of a resilient force exerted by the inclined arms  24  of the terminals  20 . The contacting portions  22  disengage with the daughter PCB  200  and the daughter PCB  200  can be pulled out by ZIF. Successively, the first stopper  19  engages with the wedge  37  and prevents the sliding guide  30  from moving out of the insulative housing  20 . 
     In the present invention, a normal mating force between the daughter PCB  200  and the terminals  20  is produced from a downward movement of the contacting portion  22 . Since the downward movement is controlled with the position/dimension of the wedge  37  and the second stopper  48 , the normal mating force can be controlled. Thus, the wear between the contacting portions  22  and the daughter PCB  200  can be reduced for a controlled normal mating force. 
     It should be noted that in the present invention, the electrical connector  100  can also mate with a plug connector as well as the daughter PCB  200 . 
     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.