Abstract:
A card connector having a housing with contacts. A cover mounted to the housing and having a card insertion slot that receives a card. The card having a contact portion corresponding to the contacts of the housing. A locking member that locks the cover to the housing. The locking member is slideably mounted on the housing and has a cam surface that engages an end of the card. The locking member pushes the card adjacent to the contacts so that the contact portion slides across the contacts of said housing to wipe contaminants from a surface of said contact portion and the contacts to improve an electrical connection therebetween.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The invention relates to a card connector. More specifically, the invention relates to a card connector that wipes contaminents from contact points of a card and contacts of a card connector before electrical engagement.  
         DESCRIPTION OF THE PRIOR ART  
         [0002]    Card connectors used for recording mediums, such as IC (integrated circuit) cards and Subscriber Identity Module (SIM) cards of portable terminals, are commonly known. One example of such a card connector is disclosed in U.S. Pat. No. 6,227,893. The card connector has a base, a cover rotatably attached to the base, and a lock bar for engaging the cover when the cover is pressed down. The lock bar is pivotally supported on the base so as to be rotatable. A card is inserted into the cover and electrical connections are established between external terminals of the card and contacts provided on the base when the lock bar engages the cover.  
           [0003]    Another example of a card connector or guide for an IC card is disclosed in Japanese Unexamined Patent Publication Number 11(1999)-161742. The card connector has a cover for housing an IC card and a base for rotatably supporting the cover. Electrical connections are established between external terminals of the IC card and contacts provided on the base by rotating the cover towards the base. A card lock for locking the IC card and a cover lock for locking the cover to the base are slidably provided on the base to ensure a positive engagement between the external terminals and the contacts.  
           [0004]    In the existing card connectors, the cover is engaged with the base by means of the lock bar so that the external terminals of the card and the contacts are connected. The external terminals are simply pressed and/or locked onto the contacts such that the contact positions of the external terminals and the contacts do not change. Because no wiping occurs between the external terminals and the contacts, if a thin film of contaminants is formed on the external terminals and/or contacts, there is a possibility of a faulty electrical connection between the external terminals and the contacts.  
           [0005]    It is therefore desirable to develop a card connector that establishes optimal electrical connections between external terminals of a card and contacts housed in the connector.  
         SUMMARY OF THE INVENTION  
         [0006]    The invention relates to a card connector having housing provided with contacts. A cover having a card insertion slot that receives a card. The card having a contact portion corresponding to the contacts of the housing. A locking member locks the cover to said housing. The locking member engages an end of the card and pushes the card adjacent to the contacts so that the contact portion slides across the contacts of said housing and is electrically connected thereto.  
           [0007]    The invention further relates to a method of removing contaminents from contact points in a card connector. A card having contact portions is inserted into a cover. The cover is rotated to engage a surface of a locking member so that the locking member moves away from the cover so that the cover engages a housing. The locking member locks the cover to the housing and pushes the card adjacent to contacts in the housing so that the contact portion slides across the contacts to wipe any contaminants therefrom. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    [0008]FIG. 1 is a perspective view of a connector according to a first embodiment of the present invention.  
         [0009]    [0009]FIG. 2 is a perspective view of a connector according to a second embodiment of the present invention.  
         [0010]    [0010]FIG. 3 is an exploded perspective view of the connector of FIG. 1.  
         [0011]    [0011]FIG. 4 is a perspective view of a bottom of the connector of FIG. 2.  
         [0012]    [0012]FIG. 5 is a partial magnified view of a locking operation of a cover. FIG. 5A shows a state in which the cover is in contact with a lock bar; FIG. 5B shows the state in which the cover and the lock bar are in cam engagement; FIG. 5C shows the state in which the cover is being pressed further downward after cam engaging with the lock bar; and FIG. 5D shows the state in which the cover is completely engaged by the lock bar and a card is pressed by the lock bar. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0013]    [0013]FIGS. 1 and 3 show a first embodiment of a card connector  1  according to the present invention. As shown in FIG. 1, the connector  1  comprises a housing  2  and a cover  6 . The housing  2  has a substantially rectangular base and is attached to a circuit board (not shown). The cover  6  is rotatably attached to the housing  2  and pivots between an open position (not shown) and a closed position (shown in FIG. 1). The cover  6  has a card insertion slot  40  for receipt of a card  70  (shown in FIG. 5), such as a Subscriber Identity Module (SIM) card. A lock bar  10  locks the cover  6  in a closed position so that external terminals (not shown) of the card  70  electrically contact a plurality of contacts  12  in the housing  2 . The housing  2  and the cover  6  may be formed of a resin.  
         [0014]    As shown in FIG. 1, the housing  2  is provided with the contacts  12 . The contacts  12  are formed from a metal having elasticity. As shown in FIG. 3, six openings  20  are formed on a main surface  18  of the housing  2  and extend in a lengthwise direction of the housing  2 . The contacts  12  are insert molded to the housing  2  so that contact portions  12   b  of the contacts  12  project from the openings  20  to contact the external terminals (not shown) of the card  70 . The contacts  12  curve upward and protrude past the main surface  18 . An opening  22  is formed adjacent to the openings  20 , and a cutout  16  is formed on a base end  4  of the housing  2 . Tines  12   a  of the contacts  12  protrude through the cutout  16  and through the opening  22  and away from the cutout  16 . The tines  12   a  are surface mounted to a circuit board (not shown).  
         [0015]    As shown in FIG. 1, a pair of outwardly facing shafts  14  projects from the base end  4  of the housing  2  in a direction perpendicular to an insertion direction  3  of the card  70 . As shown in FIG. 3, the shafts  14  are integrally formed with the housing  2  and project outward toward the sides of the housing  2 . An end of the cover  6  has a pair of shaft receiving portions  5  that correspond to the shafts  14  and receive the shafts  14 . The shaft receiving portions  5  are rotatably mounted on the shafts  14  by engagement. The shafts  14  act as a pivot point for the cover  6 .  
         [0016]    A curved cutout  7  is provided at a free end portion  8  of the cover  6  for insertion of a finger therethrough when the card  70  is to be removed. The free end portion  8  is configured so that it is fixed by a lock bar or lock member  10  that engages with an engagement protrusion  9  when the cover  6  is rotated to the closed position.  
         [0017]    As shown in FIG. 3, a support portion  26  is formed at an end  24  opposite the base end  4  that slidably supports the lock bar  10 . The support portion  26  has a pair of horizontally separated rails  28  formed as blocks. Grooves  32  are formed on each of the rails  28 . The grooves  32  extend rearward to stop portions  34  and are open to the sides. A recess  44  (most clearly seen in FIG. 4) extends along a bottom surface of the lock bar  10  and opens downward and to the rear. The recess  44  houses a pair of first plate springs  30 . The first plate springs  30  project from interior sides of the rails  28  to face each other. A front end portion of the first plate springs  30  is bent slightly forward and in the insertion direction  3  of the card  70 . Each first plate spring  30  has a tip  30   a . The first plate springs  30  have L-shaped attachment ends  52  (most clearly seen in FIG. 4). The attachment ends  52  are press-fit within a pair of L-shaped grooves  50  (most clearly seen in FIG. 4) formed in bottom surfaces of the rails  28 . Because the first plate springs  30  extend along a rear surface  70   a  of the card  70 , the region occupied by the lock bar  10  may be made small.  
         [0018]    As shown in FIGS. 1 and 3, the lock bar  10  is a rod shaped member formed of a resin. The lock bar  10  extends between the rails  28  and has a pair of guide grooves  36  that receives the rails  28 . The shape of the guide grooves  36  corresponds to the cross-sectional form of the rails  28 . The lock bar  10  is configured so that the lock bar  10  is slidably guided by the rails  28  in the insertion direction  3  of the card  70 . A card pressing portion  38  is provided at the card insertion opening  40  of the cover  6 . The card pressing portion  38  faces an end of the card  70  and is positioned between the guide grooves  36 . A finger placing portion  60  is formed on an upper part of the pressing portion  38  of the lock bar  10 . A plurality of grooves or steps  60   a  is formed on the finger placing portion  60  to prevent slipping. A pair of cam surfaces  42  facing the card insertion opening  40  is formed at both ends of the lock bar  10 . The cam surfaces  42  cam engage with the engagement protrusions  9  of the cover  6  to slide the lock bar  10 .  
         [0019]    As shown in FIG. 3, a second plate spring  54  is mounted at an end  11  of the cover  6  by press-fitting or the like. A tip  54   a  of the second plate spring  54  is bent toward an interior of the cover  6  so that the second plate spring  54  presses a distal end of the inserted card  70  to urge the card  70  backward. Because no force is applied to the card  70  in the insertion direction  3 , the card  70  protrudes slightly from the card insertion opening  40  to facilitate removal thereof by a finger that co-operates with the cutout  7 .  
         [0020]    The spring rate of each of the first plate springs  30  and the second plate spring  54  are set so that the ratio of the spring rate of the second plate spring  54  to the first plate spring  30  is approximately 3:40. Because the spring rate of each of the first plate springs  30  is far greater than the spring rate of the second plate spring  54 , when the cover  6  is locked in the closed position, the card  70  is pressed in the insertion direction  3  by the lock bar  10  so that the card  70  is in a predetermined position. Although the spring rate ratio is illustrated by an approximate numeric value, the ratio of the spring rates is not limited to this numerical value. As long as each of the plate release springs  30  has a larger spring rate with respect to the second plate spring  54 , any value may be employed.  
         [0021]    As shown in FIG. 3, the housing  2  has a cover ejection spring  62  that engages the cover  6 . The cover ejection spring  62  has a first end fixed to the housing  2  and a free end  62   a  in a vicinity of the base end  4  of the housing  2 . The free end  62   a  is inclined upward and abuts an interior surface of the cover  6  in a vicinity of the end  11  so that when the cover  6  is in a closed position, the cover  6  is urged upward. When the engagement between the cover  6  and the lock bar  10  is released, the cover ejection spring  62  pushes the cover  6  to an upward position.  
         [0022]    The locking operation of the cover  6  will now be described in greater detail with reference to FIG. 5. Shown in FIG. 5A, the cover  6  is in an open position and is biased upward by the spring  52 . A card  70  is inserted into the insertion opening  40  of the cover  6  in the insertion direction  3 . The card  70  is inserted until the card  70  rests against the second spring plate  70 . The lock bar  10  is urged forward by tips  30   a  of the first plate springs  30  pressing a rear surface  46  (most clearly seen in FIG. 4) of the lock bar  10  in the insertion direction  3  such that an abutment surface  48  of the lock bar  10  abuts the stop portions  34  of the rails. The cover  6  is rotated about the shafts  14  and toward the housing  2  toward the closed position. The engagement protrusions  9  of the cover  6  contact the cam surfaces  42  of the lock bar  10 , which is being urged in the insertion direction  3  by the first plate springs  30 .  
         [0023]    As shown in FIG. 5B, when the cover  6  is pressed further downward, the engagement protrusions  9  cam engage with the cam surfaces  42  to force the lock bar  10  to move backward, in the direction indicated by arrow  56 , against the force of the first plate springs  30 . As the lock bar  10  moves backward, protrusions  46   a  (most clearly seen in FIG. 4) on the rear surface  46  of the lock bar  10  abut the first plate springs  30  to restrict movement. As shown in FIG. 5C, as the cover  6  is continued to be pressed downward, the engagement protrusions  9  disengage from the cam surfaces  42  and press the lower ends of the cam surfaces  42  to move the lock bar  10  to a rearmost position.  
         [0024]    As shown in FIG. 5D, when the cover  6  is pressed still further downward, the engagement protrusions  9  pass under the lower ends of the cam surfaces  42  and under an engagement surface  58  of the lock bar  10 . The lock bar  10  is pushed forward by the first plate springs  30  in the insertion direction. The pressing portion  38  of the lock bar  10  presses the rear surface or end  70   a  of the card  70  against the force of the second plate spring  54  to move the card  70  slightly, thereby locking the cover  6  and pushing the card  70  further into the cover  6 . The amount of movement d is approximately 0.5 mm. This movement causes the external terminals (not shown) of the card  70  and the contacts  12  to wipe against each other. The wiping removes any contaminants or dirt from the contact points on the external contacts (not shown) and/or the contacts  12  to expose a clean metallic surface for an optimal electrical connection.  
         [0025]    To remove the card  70  from the connector  1 , a finger is placed on the finger placing portion  60  that is formed on the upper part of the pressing portion  38  of the lock bar  10 . The lock bar  10  is slid in the direction opposite the insertion direction  3  of the card  70  to release the engagement between the lock bar  10  and the engagement protrusions  9  of the cover  6 . When the cover  6  is unlocked, the cover ejection spring  62  forces the cover  6  upward. At the same time, the card  70  is pushed out from the card insertion opening  40  by the second plate spring  54  to facilitate removal of the card  70 .  
         [0026]    [0026]FIGS. 2 and 4 show a second embodiment of a card connector  100  according to the present invention. The second embodiment of the card connector  100  is substantially similar to the first embodiment of the card connector  1 . Parts similar to the first embodiment will not be described with reference to the second embodiment and like parts will be designated by like reference numerals.  
         [0027]    As shown in FIGS. 2 and 4, the connector  100  has a cover  106 . The cover  106  is formed from a metal plate and has a cutout  107 . Shaft receiving portions  105  for receiving the shafts  14  of the housing  2  are formed at an end portion of the cover  106  by punching and bending the metal plate. Both lateral edges of the cover  106  are bent downward to form side walls  111  that cover lateral edges of the housing  2 . At an end of the cover  106  on the side of the shaft receiving portions  105 A, a pair of downwardly projecting tongue pieces  113  ( 113   a ,  113   b ) are formed by bending. The tongue pieces  113  act as stoppers if the card  70  is excessively inserted into the housing  2 . A second plate spring  154  is integrally formed with the tongue piece  113   a  and inclines toward the interior of the cover  106 . The second plate spring  154  abuts a distal end of the card  70  when the card  70  is inserted into the housing  2  and slightly pushes the card  70  back out of the housing  2 .  
         [0028]    Engagement protrusions  109  extend outward from a side of a free end portion  108  of the side walls  111 . The engagement protrusions  109  are bent in a U-shape and extend beneath the lock bar  10 . The engagement protrusions  109  have a height h, which is the same height as the engagement protrusions  9  of the connector  1  so that the engagement protrusions  109  are engaged by the lock bar  10  to lock the cover  106  to the housing  2 .  
         [0029]    The card connector  100  of the second embodiment operates in a substantially similar manner as the card connector  1 , wherein after the engagement protrusions  9  pass under the lower ends of the cam surfaces  42  and under an engagement surface  58  of the lock bar  10 , the lock bar  10  is pushed forward by the first plate springs  30  in the insertion direction. The pressing portion  38  of the lock bar  10  presses the rear surface or end  70   a  of the card  70  against the force of the second plate spring  54  to move the card  70  slightly, thereby locking the cover  6  and pushing the card  70  further into the cover  6 . This movement causes the external terminals (not shown) of the card  70  and the contacts  12  to wipe against each other. The wiping removes any contaminants or dirt from the contact points on the external contacts (not shown) and/or the contacts  12  to expose a clean metallic surface for an optimal electrical connection.  
         [0030]    The foregoing illustrates some of the possibilities for practicing the invention. Many other embodiments are possible within the scope and spirit of the invention. For example, the lock bar  10  may be rotatably mounted to the cover  6  instead of being slidable. In this case, a similar wiping effect may be obtained by pressing the card  70  when the cover  6  is locked. In addition, the first and second plate springs  30 ,  54  may alternatively be coil springs or torsion springs. It is, therefore, intended that the foregoing description be regarded as illustrative rather than limiting, and that the scope of the invention is given by the appended claims together with their full range of equivalents.