Abstract:
An electrical contact ( 10 ) which can engage a mating terminal ( 50 ) for electrical connection and detachable latching thereto. The contact includes a piece of sheet metal bent to form at least one guide plate ( 13, 14 ) and a bias plate ( 15 ) lying facewise adjacent to the guide plate. The bias plate has a front end upper portion or nose ( 38 ) with a top ( 104 ) that lies above an adjacent location ( 24, 25 ) on the guide plate, but the nose can be resiliently downwardly deflected and then tends to spring up again. A recess ( 17 ) in the bottom of the guide plate front portion receives the mating terminal, and the upper bias of the nose of the bias plate keeps the guide plate pressed down against the terminal lying in its recess, to thereby latch the two connectors together.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    A plug connector for applications such as in mobile telephones, commonly includes a row of contacts that make electrical connection with corresponding terminals on the mating connector, and a separate latch that holds the connectors together. It is possible for the contacts to provide some retention force, but such retention force is usually low so reliable latching requires a separate latch. It would be desirable if the contacts themselves provided a strong latch and the contacts could be constructed at low cost of sheet metal.  
         SUMMARY OF THE INVENTION  
         [0002]    In accordance with one embodiment of the present invention, applicant provides a contact that includes a durable latch function in addition to an electrical contacting function, in a contact that can be constructed at low cost. The contact includes a piece of sheet metal that is bent to form a biasing plate and at least one guide plate, the two plates joined by a bend and the two plates lying facewise adjacent to each other. Front portions of the plates, which are designed to mate to a terminal of a matting connector, have tops and bottoms. The top of the front portion of the biasing plate forms a nose whose top initially lies above an adjacent location on the guide plate, but which can be resiliently deflected downwardly. Accordingly, when the front portion of the contact enters a cavity of the mating connector, the height of the contact can be reduced by downward deflection of the nose, and the contact then resiliently expands vertically.  
           [0003]    The bottom of the guide plate has a recess that receives a terminal of the mating connector. The resilient vertical expansion of the contact, assures that the terminal presses firmly against the walls of the recess, and allows shoulders formed by the terminal and recess to resist pull out of the contact out of the cavity.  
           [0004]    The contact is preferably formed with two guide plates, and with the bias plate sandwiched between the guide plates. The lower ends of the guide plates are joined by a longitudinally-extending bend that lies under the bias plate. The top of the bias plate is joined in a bend to the top of one of the guide plates.  
           [0005]    The novel features of the invention are set forth with particularity in the appended claims. The invention will be best understood from the following description when read in conjunction with the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]    [0006]FIG. 1 is a plan view of a piece of sheet metal that is a punched blank from which a contact of a first embodiment of the invention can be formed.  
         [0007]    [0007]FIG. 2 is a front and top isometric view of a contact formed from the punched blank of FIG. 1.  
         [0008]    [0008]FIG. 2A is a sectional view taken on line  2 A- 2 A of FIG. 2.  
         [0009]    [0009]FIG. 3 is a sectional side view of two connectors in a fully mated position, and including a modified version of the contact of FIG. 2 mounted in a first connector and a terminal mounted in a second connector.  
         [0010]    [0010]FIG. 4A is a view of the connectors of FIG. 3, shown at the beginning of mating of the connectors.  
         [0011]    [0011]FIG. 4B is a view similar to FIG. 4A, but with the connectors in a position halfway between the beginning of mating position of FIG. 4A and the fully mated position of FIG. 3. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0012]    [0012]FIG. 1 illustrates a piece of sheet metal  11  that has been punched from a larger sheet and that forms a punched blank. The blank forms two outer plates, or guide plates  13 ,  14  and an inner plate, or bias plate  15 . The two guide plates are joined by a wide first bend region  16 A. The first guide plate  13  is joined to the bias plate  15  by a narrow second bend region  28 A.  
         [0013]    The first bend region  16 A extends along almost the entire length of the blank  11  which will become the contact, in front F and rear R directions, which are longitudinal M directions. The first bend region has two openings or recesses  17 ,  18 . The first recess  17  is used to receive a mating terminal and to latch the contact formed by the blank  11  to a mating connector, as will be described below. The wide bend region forms lower ends  21 ,  22  of the guide plates. The second bend region  28 A extends only a short distance, along the rear portion  100  of the blank that will form the contact, with only one closed recess  29  therealong. A front portion  101  of the blank lies opposite the rear portion. The front and rear portions form front and rear portions of the contact and of the plates. The second bend region  28 A forms upper ends  31 ,  32  of the guide plate  13  and bias plate  15 . Applicant notes that the blank is formed with a punched region  34  and with a holding tooth  36 . The bias plate  15  has a rounded front end  39 , a convex nose at  38 , and a concave zone  37  rearward of the nose.  
         [0014]    The guide plates form front ends at  26  and  27 , shoulders at  24 ,  25 , an edge at  23  and a rear end at  33 . A crimp projection  41  projects from one of the guide plates, and can be crimped around a wire to connect the wire to the contact.  
         [0015]    [0015]FIG. 2 shows the blank folded to form a contact  10  which includes the two guide plates  13 ,  14  joined at a first bend  16  formed at lower ends of those plates, and the bias plate  15  which is joined by a second upper bend  28  to the upper end of the first guide plate  13 . The front end of the upper bend is closer to the rear end of the contact than the middle  107 . As shown in FIG. 2A, the bias plate  15  is sandwiched between the first and second guide plates  13 ,  14 , and the plates lie facewise adjacent to one another. It is also noted that the bias plate has a lower end  102  which is much higher than the lower ends  21 ,  22  of the guide plates. The lower and upper bends are longitudinal bends because they are bends about longitudinal axes such as  106  and  108  (FIG. 2A).  
         [0016]    [0016]FIG. 2 shows that the convex nose  38  initially projects above adjacent locations  24 ,  25  at the upper ends or tops of the guide plate front portions. However, the bias plate is resiliently deflectable downwardly, and in this case it can be deflected downwardly so that the top  104  of the nose is at the same height as the locations  24 ,  25  on the guide plates.  
         [0017]    [0017]FIG. 4A illustrates a modified form of the contact at  10 A, wherein the bias plate at  15 A has a portion  110  of increased resilience. The increased resilience portion has a length between its front and rear ends that is more than six times its height in the up U and down D directions.  
         [0018]    [0018]FIG. 4A shows the contact as it first enters a cavity  112  of the mating connector  48  and engages a partially rearwardly-facing terminal shoulder  116 . The height of the front of the contact under the top  104  is greater than the height W between the top and bottom walls  52 ,  50  near the entrance of the cavity. A projecting portion  54  of the mating connector terminal  50  forms the lower wall of the cavity. The height of the contact  10 A under the top  104  is greater than the vertical distance W at the entrance to the cavity. As shown in FIG. 4B, the squeezing force between the top and bottom walls of the cavity results in the nose  38  of the bias plate being downwardly resiliently deflected to the height W. FIG. 3 shows the connectors fully mated. The nose  38  of the bias plate has moved up again relative to the guide plates as the shoulders  24 ,  25  of the guide plates move down.  
         [0019]    In the fully inserted position of FIG. 3, the projecting portion, or latching nose  54  of the terminal  50  enters the recess  17  at the lower ends of the two guide plates. The walls of the recess  17  form partially rearwardly-facing shoulders at  120  (FIG. 2) and the upper surface of the latching nose  54  forms a partially forwardly-facing shoulder. The shoulders engage and prevent the contact from being withdrawn rearwardly from the mating connector  48 , without downwardly deflecting the nose  38  on the bias plate relative to the guide plates, to the position shown in FIG. 4B. The moderately long downward travel B of the nose  38 , required for a pullout of the contact, results in a reliable latching of the two connectors together. The distance B is preferably at least 5% of the total height A of the cavity and of the contact front portion that enters the mating connector cavity.  
         [0020]    [0020]FIG. 3 shows that the contact  10 A is held in place in an insulative housing  122  of the first connector  45  by a portion of the first connector entering the recess  18  at the bottom of the rearward end of the guide plates, and by the holding tooth  36 . The crimp projection  41  is shown crimped around a conductor of a wire. The connector has a plurality of contacts of the type illustrated at  10  or  10 A whose latchings result in the requirement for a considerable pull out force to separate the connectors. The second connector comprises a circuit board  51 , the lower end  53  of the terminal soldered to the board. The terminal has about the same width C as the contact.  
         [0021]    While terms such as “top”, “bottom”, etc. have been used to describe the contacts and connectors as they are illustrated, it should be understood that the contacts and connectors can be used in any orientation with respect to the Earth.  
         [0022]    Thus, the invention provides a contact for mounting in a first connector and for mating with a terminal of a second connector, wherein the contact has a front portion that can resiliently expand and contract in height, and that can be used to provide large and reliable latching forces to hold the connectors releaseably latched together. The contact includes a piece of sheet metal that is bent to form a guide plate and a bias plate, with a bend in the sheet metal that connects them so they lie facewise adjacent to one another. The bias plate has a front portion that is resiliently deflectable downwardly and that springs up again, so the bottom of the guide plate can engage a bottom wall of a cavity while the top of the front portion of the bias plate can engage an upper end of the cavity. The bottom of the guide plate (or the top of the bias plate) can have a recess that receives a projection of the mating connector, the projection preferably being the terminal that makes electrical engagement with the contact. Shoulders on the walls of the recess and on the terminal abut to resist rearward movement of the contact out of the cavity, although such rearward movement can be achieved by sufficient pullout force to downwardly deflect the front portion of the bias plate with respect to the bias plate(s).  
         [0023]    Although particular embodiments of the invention have been described and illustrated herein, it is recognized that modifications and variations may readily occur to those skilled in the art, and consequently, it is intended that the claims be interpreted to cover such modifications and equivalents.