Abstract:
Disclosed is an electrical connector for connecting a first circuit board to a second circuit board. The electrical connector for mounting on the second circuit board comprises an insulative housing having a slot for receiving the first circuit board therein. A lever is rotatably mounted in a recess at an end of the housing. The lever rotatably moves in a first plane to affect the position of the first circuit board in the slot. The lever includes a support arm with a vertical surface constantly juxtaposed to a portion of the housing to limit the lever from rotating in a second plane angular to the first plane.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a card edge connector for connecting a daughter circuit board to a mother circuit board. The invention particularly relates to a card edge connector which comprises a lever that can be smoothly rotated inwardly to latch the daughter circuit board in the connector or outwardly to eject the daughter circuit board from the connector. 
     BACKGROUND OF THE INVENTION 
     Edge card connectors are used for connecting a circuit board with conductive pads along a lower edge, such as a daughter circuit board or a daughter card, to an underlying circuit board, such as a mother circuit board. Terminals loaded in a housing of the connector along a slot for receiving the daughter circuit board connect the conductive pads on the daughter circuit board to conductors on the mother board. Edge card connectors typically employ a lever disposed at one side of a housing of the connector, which is rotated inwardly to latch the daughter circuit board in a slot in the connector and rotated outwardly to eject the daughter circuit board from the slot in the connector. 
     The levers for such card edge connectors sometimes undesirably rotate or swivel in a plane which is perpendicular to a plane defined by the intended rotational movement of the lever. The plane of rotational movement is normally parallel to the slot in the connector. The undesirable rotation or swiveling of the lever is aggravated when the lever is subjected to lateral forces which are typical in the manufacturing, assembly and shipping of these connectors. Such lateral forces can cause the lever to excessively rotate or swivel thereby unfortunately causing damage to the lever. 
     These levers are also prone to vibration. As a result of vibration, the contact impedance between the conductive pads of the daughter circuit board and the terminals in the connector can become unstable. 
     FIG. 8 shows a conventional edge card connector according to U.S. Pat. No. 5,470,240. The structure of the edge card connector includes an insulative housing  1 , a plurality of conductive contacts  3  mounted in the insulative housing  1  for connection to connecting pads of the circuit board (not shown), and two levers  5  pivotally mounted at pivot points  8  on the insulative housing  1  at two opposite ends, respectively. The levers  5  each comprise a wrench arm  7  at the bottom, and a side projection  9  near the top thereof. When the levers  5  are rotated inwardly, the side projections  9  of the levers  5  are engaged into respective side recesses  4  at two opposite side edges of the daughter circuit board  2 . To remove the daughter circuit board  2  from the insulative housing  1 , one lever  5  is rotated outwardly to disengage the side projection  9  from the corresponding side recess  4 , and at the same time the respective wrench arm  7  is rotated upwardly to lift the daughter circuit board  2  from the insulative housing  1 . The main drawback of this structure is that the edge card connector has no means to protect the levers against destruction from lateral impact. 
     FIG. 9 shows another structure of a prior art edge card connector comprising a housing  1 ′ for receiving a daughter circuit board (not shown) to connect contact pads on the circuit board to terminals  3 ′. A lever  5 ′ has a wrench arm  7 ′ for ejecting the daughter circuit board from the connector  1 ′. However, this structure is still not satisfactory in function. The expanded opposite end of the insulative housing  1 ′ which is designed to reinforce the structural strength of the insulative housing greatly increases the transverse dimension of the edge card connector. Further, the lever  5 ′ has flanges  9 ′ that are moved by rotation of the levers  5 ′ in and out of the space between respective parallel upright supports  6  of the insulative housing  1 ′ to stabilize movement of the levers  5 ′. However, when the levers are turned outwardly, the flanges are disengaged from the upright supports, thereby becoming vulnerable to damage from lateral impact. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an edge card connector that has a lever for holding a daughter circuit board firmly in position against vibration. It is another object of the present invention to provide an edge card connector for receiving a daughter circuit board having a lever that can withstand damage from lateral impact. 
     To achieve these and other objects of the present invention, there is provided an electrical connector for connecting a first circuit board to a second circuit board. The electrical connector comprises an insulative housing having a first wall and a second wall extending from a first end to a second end and defining a top face. A slot in the top face extends from the first end to the second end between the first and second walls for receiving the first circuit board therein. A recess is also disposed in at least one of the first end and the second end. Terminal cavities are disposed in at least one of the first wall and the second wall adjacent to the slot. A plurality of terminals are mounted in the terminal cavities. Each of the terminals have a contact portion extending into the slot for contacting conductive pads on the first circuit board when received in the slot and a tail portion extending out of the insulative housing to contact conductors on the second circuit board. A lever is rotatably mounted in the recess at one of the first end and the second end of the insulative housing. The lever rotatably moves in a first plane to affect the position of the first circuit board in the slot. The lever includes a support arm with a vertical surface constantly engaged with a portion of the housing to limit the lever from rotating in a second plane angular to the first plane. 
     As also disclosed herein, the lever has two sides and the arm extends from each side. The recess in the insulative housing may also include a first wall and a second wall. The first wall and the second wall of the recess preferably extend upwardly from the top face of the housing and the support arm is adjacent to the first wall. The vertical surface of the support arm may be adjacent to the first upstanding wall. The housing may further include a first aperture in a first wall of the recess in registry with a second aperture in the second wall of the recess, and the lever includes a first shaft and a second shaft for reception in respective ones of the first aperture and the second aperture to rotatably mount the lever in the recess. A lower end of the support ann is preferably chamfered. The lever also may have an ejecting surface for engaging a portion of the first circuit board and lifting the first circuit board up in the slot upon rotation of the lever. The lever may also have latching surface for engaging a portion of the first circuit board and holding the first circuit board down in the slot. The lever may further have an extended gripping section for manually rotating the lever. 
     As further disclosed herein, the support arm preferably comprises a horizontal segment extending outwardly from the first side or the second side of the lever and a vertical segment extending downwardly from the horizontal segment. 
     Other objects, features and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The features of this invention which are believed to be novel are set forth with particularity in the appended claims. The invention, together with its objects and the advantages thereof, may be best understood by reference to the following description taken in conjunction with the accompanying drawings, in which like reference numerals identify like elements in the figures and in which: 
     FIG. 1 is a perspective view of an edge card connector according to the present invention; 
     FIG. 2 is a perspective detailed view of a portion of the connector in FIG. 1; 
     FIG. 3 is an exploded view of FIG. 2; 
     FIG. 4 is a cross sectional view taken along segment  4 — 4  of FIG. 2; 
     FIG. 5 is a broken away schematic drawing of the connector of FIG. 1 with a lever turned outwardly to receive a daughter circuit board; 
     FIG. 6 is a broken away schematic drawing of the connector of FIG. 1 with the daughter circuit board inserted into the connector and the lever turned inwardly and engaged with the circuit board; 
     FIG. 7 is a broken away schematic drawing of the connector of FIG. 1 with the lever turned outwardly and pushing the daughter circuit board out of the connector; 
     FIG. 8 illustrates a connector for a daughter circuit board according to the prior art; and 
     FIG. 9 illustrates an alternative connector for a daughter circuit board according to the prior art. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 shows the edge card connector  10  of the present invention. The connector  10  includes an insulative housing  11  comprising a first wall  110  and second wall  110  extending from a first end  113  to a second end  113 . The walls  110  define a top face  112  and provide a slot  114  between the walls  110 . Terminal cavities  111  are disposed in the first wall and the second wall adjacent to the slot  114 . Terminals  13  are disposed in each of the terminal cavities  111 . Each terminal has a contact portion  13   a  extending into the slot for contacting conductive pads on a first circuit board or daughter circuit board  12  (FIG. 5) inserted into the slot. Moreover, a tail portion  13   b  extending out of the housing  11  contacts conductors on a second circuit board or mother circuit board (not shown). At least one board lock  14  or other fastening device may be used to secure the connector  10  to the mother circuit board. First and second recesses  119  are disposed in the first and second ends  113  of the housing  11 , respectively. First and second levers  15  are disposed in first and second recesses, respectively, at both ends  113  of the housing  11 . 
     FIGS. 2-4 show one end  113  and the associated lever  15  of the connector  10  of the present invention in greater detail. In FIG. 3, the lever  15  is removed from the housing for illustrative purposes. Each of the recesses  119  include first and second recess walls  118  having notches  116  therein each descending downwardly and terminating in a circular aperture  117 . First and second walls  118  of each recess preferably extend upwardly from the top face  112  of the housing  11 . 
     The lever  15  is molded from an insulative material and includes a bottom wall  151  and a top wall  152 . A gripping section  154  extends upwardly from the top wall  152  of the connector to facilitate manually rotating the lever. Opposed first and second walls  157  of the lever define a central slit  153 . Shafts  155  extend outwardly from each of the first and second sidewalls  157  of the lever. The shafts are inserted through the notches  116  of walls  118  of the recess  119  in the housing and seat in the apertures  117  at the bottom of the notch  116  to rotatably mount the lever  15  in the recess  119  of the housing  11 . Other means of rotatably mounting the lever  15 , such as by fashioning apertures in the lever for receiving shafts projecting from the walls  118  of the recess  119 , although not shown, are also contemplated as part of the invention. The lever  15  also includes resilient fingers  158  which are free to flex inwardly and outwardly to grip a portion of the first circuit board that is received in the slit  153 . A mid-portion of the front surface of the top wall  152  of lever  15  includes an arcuate recess  152   a  to facilitate reception of the portion of the first circuit board. 
     An inventive aspect of the lever  15  of the connector  10  is the formation of support arms  159  on one or both sides of the lever  15 . The support arms  159  preferably comprise a first horizontal segment  159   a  extending outwardly from a respective sidewall  157  of the lever  15  and a vertical segment  159   b  descending downwardly from the horizontal segment  159   a . The vertical segment  159   b  defines an interior vertical surface  159   c  as best seen in FIG.  4 . Preferably, the lower end of the vertical surface  159   c  has a chamfered edge to facilitate insertion of the lever  15  into the recess  119  during assembly. Additionally, top edges of the recess walls  118  may be chamfered to also facilitate insertion of the lever  15  into the recess  119  during assembly. The lower end of side walls of the lever  15  include formations  157   a  including a stop block  157   b  with an inner angular surface  157   c  for engaging a front surface  118   a  of recess  119  in the housing to limit inward rotation of the bottom wall  151  of the lever  15 . 
     FIGS. 5-7 show operation of the lever  15  with respect to insertion and ejection of the first circuit board or daughter circuit board  12  in and from the connector  10 , respectively. A portion of one of the walls  110  is removed in FIGS. 5-7 to illustrate the interaction between the lever  15  and the daughter circuit board  12 . The daughter board  12  includes contact pads  121  arranged along a lower edge  122 . An outer edge  123  of the daughter board includes a side notch  124  for latching purposes. Respective ones of the contact pads  121  will be engaged with contact portions  13   a  of the terminals  13  to effectuate electrical connection between the contact pad  121  and an appropriate conductor on the mother board (not shown). 
     FIG. 5 shows the connector  10  with the lever  15  in an open position poised to receive the first circuit board  12  within slot  114 . The daughter circuit board  12  is inserted into the slot  114  in the housing  11  in the direction of arrow A during which a portion of the outer edge  123  enters into the slit  153  in lever  15  (FIG.  2 ). The slit  153  is aligned with the slot  114  to facilitate entry of the portion of the outer edge  123  of the daughter circuit board  12  into the slit  153 . As the daughter circuit board  12  is inserted into the slot  114 , the lower edge  122  of the circuit board  12  engages a top surface of the bottom wall  151  of the lever  15 , thereby urging the bottom wall  151  downwardly and rotating the lever  15  counterclockwise in the direction of arcuate arrow B in a plane C about shafts  155  seated in apertures  117 . The arcuate recess  152   a  (FIGS. 2-4) facilitates entry of the top wall  152  into the side notch  124  and reception of the portion of the outer edge  123  into the slit  153  of lever  15 . 
     FIG. 6 shows the daughter circuit board  12  completely inserted into the slot  114  of the housing  11 . The bottom surface of the bottom wall  151  is in engagement with the bottom of the recess  119  of the housing  11  and is thereby at the limit of the inward rotation of the lever  15 . Additionally, the top wall  152  is engaged with the side notch  124  in daughter circuit board  12  and resilient fingers  158  are gripping opposing sides of the daughter circuit board  12 . The top wall  152  engages the side notch  124  to latch the daughter circuit board  12  within slot  114  of the housing  11 . Furthermore, the portion of the outer edge  123  below the side notch  124  is nested within the slit  153  of the lever  15 . Accordingly, although not visible from the view in FIG. 6, contact portions  13   a  of terminals  13  are in engagement with contact pads  121  on the daughter circuit board  12 . 
     To eject the daughter circuit board  12  from the connector  10  in a direction of arrow D, the lever  15  is rotated in the direction of arcuate arrow E in the plane C as shown in FIG.  7 . Upon rotation, the top surface of bottom wall  151  of the lever  15  is rotated upwardly to engage bottom edge  122  of the daughter circuit board  12 , thereby urging the daughter circuit board in a direction of arrow D and disengaging contact pads  121  on the daughter board  12  from engagement with contact portions  113   a  of terminals  13  in cavities  111 . It can be seen that upon rotation of the lever  15  in the direction or arcuate arrow E, the top wall  152  disengages from the side notch  124  to permit the daughter circuit board  12  to move upwardly in the direction of arrow D. Moreover, resilient fingers  158  disengage from their gripping relationship with the sides of the daughter circuit board  12 . 
     All the while that the lever  15  is rotated in the directions of arcuate arrows B and E, the inner vertical surface of the vertical segment  159   b  remains in engagement or juxtaposition with a portion of outer surface of the upstanding recess walls  118 . Consequently, the lever  15  is limited from swivelling or rotating in a plane, such as planes G or F as shown in FIG. 2, that is angularly related to the plane C of rotation shown in FIGS. 2,  3 ,  5 ,  6  and  7 . Additionally, the support arm  159  also mitigates vibration of the lever  115 . 
     It will be understood that the invention may be embodied in other specific forms without departing from the spirit or central characteristics thereof. The present examples and embodiments, therefore, are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein.