Abstract:
A subscriber identity module (SIM) card connector ( 1 ) includes an insulating base ( 10 ), a plurality of contact elements ( 20 ) partially received in the base, and a one-piece switch member ( 30 ) partially received in a channel ( 13 ) defined in a top surface ( 12 ) of the base. The switch member has upper and lower contact branches ( 34, 35 ) extendingrearwardly beyond a rear face of the base. The upper contact branch has an upper contact portion ( 340 ) projecting upwardly beyond the top surface of the base. The lower contact branches have lower contact portions ( 350 ) projecting downwardly in proximity to a printed circuit board (PCB).

Description:
FIELD OF THE INVENTION 
     The present invention generally relates to a subscriber identity module (SIM) card connector, and more particularly, to a SIM card connector with an improved switch member for detecting full insertion of a SIM card. 
     BACKGROUND OF THE INVENTION 
     Subscriber identity module (SIM) cards are widely used with electrical devices, such as personal computers, notebooks, portable phones, PDAs and the like. SIM card connectors are adapted to connect SIM cards with the electrical devices. A SIM card connector usually needs a switch device for detecting full insertion of the SIM card. 
     U.S. Pat. No. 6,086,426 discloses a card connector with a switching device. The switching device includes an upper and a lower switching member. The upper and lower switching members respectively have an upper contact portion and a lower contact portion. The upper switching member further has a biasing hump for engaging with a leading edge of a card. The upper and lower switching members are assembled to the base in juxtaposition, and the upper contact portion is located above the lower contact portion. A stopper of the upper switching member limits movement of the upper contact portion. The contact portions are spaced apart from each other before the card is inserted. The biasing hump projects into an insertion path of the card. When the card is inserted into the connector and reaches its final position, the leading edge of the card slides over the biasing hump of the upper switching member, thereby pushing the upper contact portion to engage with the lower contact portion to establish an electrical connection therebetween. 
     However, the switch device needs two switch members, thus requiring a complicated manufacturing process and a high cost. 
     U.S. Pat, No. 6,130,387 discloses a switch assembly built into a connector that connects to pads of a smart card. The connector includes a frame extension or support for the switch assembly. The switch assembly has a switch element. The switch element includes a contacting part extending forwardly and downwardly in proximity to a printed circuit board, and a pedal extending laterally and upwardly from a side of the contacting part, through a hole in the frame extension or support. When the smart card is inserted into the connector, the pedal is depressed, causing the contacting part to be depressed against a circuit trace of the printed circuit board. This results in the closing of the switch. 
     However, the pedal and the contacting part are non-symmetrically formed on the switch element, which may affect the resiliency and cause a misconnection of the contacting part with the circuit trace of the printed circuit board after a period of use. 
     BRIEF SUMMARY OF THE INVENTION 
     A main object of the invention is to provide a subscriber identity module (SIM) card connector with a sensitive switch member for detecting full insertion of a SIM card. 
     Another object of the invention is to provide a SIM card connector with a one-piece switch member which is easily manufactured and which has a low profile. 
     A SIM card connector in accordance with the present invention includes an insulating base defining a plurality of recesses in a top surface thereof and a channel in the top surface and juxtaposed with the recesses, a plurality of contact elements received in the recesses, and a switch member partially retained in the channel. A block projects upwardly from a bottom of the channel. The switch member defines a longitudinal center line and has a solder tail at a front end thereof, a mounting portion to a rear of the solder tail, a switch contact at a rear end thereof and a cantilever beam between the mounting portion and the switch contact. The switch contact extends rearwardly beyond a rear face of the base and has an upper contact portion projecting upwardly beyond the top surface of the base for electrically connecting with a SIM card, and lower contact portions projecting downwardly in proximity to a printed circuit board (PCB). The upper and lower contact portions are symmetric about a vertical plane containing the center line. When fully inserted into the SIM card connector, the SIM card depresses the upper contact portion, causing the lower contact portions to establish electrical connection with a switch trace on the PCB, signaling full insertion of the card in the connector. 
     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 
     FIG. 1 is an exploded view of a subscriber identity module (SIM) card connector according to an embodiment of the present invention, together with a printed circuit board (PCB) and a SIM card; 
     FIG. 2 is a perspective view of a switch member of the SIM card connector of FIG. 1; 
     FIG. 3 is a top view of FIG. 2; 
     FIG. 4 is an assembled view of the SIM card connector of FIG. 1; 
     FIG. 5 is an assembled view of FIG. 1 with the SIM card sliding over the SIM card connector; 
     FIG. 6 is a side view of the SIM card connector mounted on the PCB with the SIM card thereon; 
     FIG. 7 is an exploded view of a SIM card connector according to another embodiment of the present invention together withal PCB and a SIM card; and 
     FIG. 8 is an assembled view of the SIM card connector of FIG. 7 mounted on the PCB. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     For facilitating understanding, like components are designated by like reference numerals throughout the various embodiments of the invention as shown in the attached drawings. 
     Referring to FIGS. 1 through 6, in a preferred embodiment, a SIM card connector  1  according to the present invention includes an insulating base  10 , a plurality of contact elements  20 , and a one-piece switch member  30 . The insulating base  10  has a planar top surface  12  for supporting a SIM card  2 . A plurality of recesses  11  are defined in the top surface  12  and communicate with either a front or a rear surface of the base  10  for receiving the contact elements  20  therein. A channel  13  is defined in the top surface  12  extending from the front to the rear surface of the base  10  for retaining the switch member  30 . A block  14  projects upwardly from a bottom (not labelled) of the channel  13  for supporting the switch member  30 . Two slots  15  are respectively defined in opposing interior side walls (not labelled) of the channel  13  and in communication with the channel  13 . 
     Since the structure of the contact elements  20  of the SIM card connector  1  is well known to those skilled in the art, a detailed description thereof is omitted herein. 
     Particularly referring to FIGS. 2 and 3, the switch member  30  defines a longitudinal center line L—L and includes a solder tail  31  at a front end thereof adapted for soldering to a PCB  3 , a planar mounting portion  32  to a rear of the solder tail  31 , a switch contact  39  at a rear end thereof, and a horizontal cantilever beam  33  between the mounting portion  32  and the switch contact  39 . The mounting portion  32  is located between the cantilever beam  33  and the solder tail  31  in both a horizontal direction and in a vertical direction. A first connecting portion  312  is formed between the mounting portion  32  and the solder tail  31 . A second connecting portion  323  is formed between the mounting portion  32  and the cantilever beam  33 . Two pairs of barbs  320  respectively protrude from opposite sides of the mounting portion  32 . 
     The switch contact  39  includes a planar portion  331  attached to a rearward end of the cantilever beam  33 , which is wider than the cantilever beam  33 . A pair of lower contact branches  35  downwardly and rearwardly extend from a rearward end of the planar portion  331 , and an upper contact branch  34  upwardly and rearwardly extends from the rearward end of the planar portion  331  and between the lower contact branches  35 . The switch contact  39  extends beyond the rear face of the base  10 . The upper contact branch  34  projects beyond the top surface  12  of the base  10 . The upper contact branch  34  has an upper contact portion  340  projecting upwardly, and each of the lower contact branches  35  has a lower contact portion  350  projecting downwardly. The upper and lower contact portions  340 ,  350  are respectively symmetric about a vertical plane containing the center line L—L. 
     Particularly referring to FIG. 4, in assembly, each contact element  20  is partially received in a corresponding recess  11  and partially exposed to the top surface  12 . The switch member  30  is partially retained in the channel  13  of the base  10  with the switch contact  39  projecting beyond the rear face of the base  10 . A front end of the cantilever beam  33  is supported by the block  14 , with a rear surface of the second connecting portion  323  abutting a front face of the block  14 . A rear portion of the cantilever beam  33  is spaced from the bottom of the channel  13 , such that a slight pressure acted on the upper contact branch  34  easily leads to a depression of the lower contact branches  35 , thereby forming an electrical connection between the lower contact branches  35  and a switch trace  301  of the PCB  3 . The mounting portion  32  is retained in the channel  13  with the barbs  320  engaging with the slots  15 . A rear surface of the first connecting portion  312  abuts against a front surface of the base  10  and the solder tail  31  is soldered to a solder trace  302  of the PCB  3 . 
     Particularly referring to FIGS. 5 and 6, when a SIM card  2  is inserted into the connector  1 , the contact portions (not labeled) of the contact elements  20  and the upper contact portion  340  of the switch member  30  are depressed and electrically connect with the contact pads (not shown) of the SIM card  2 . The downward movement of the upper contact portion  340  depresses the lower contact branches  35  and the lower contact portions  350  of the lower contact branches  35  contact the switch trace  301  of the PCB  3 , establishing an electrical connection therewith. The closing of this electrical connection signals full insertion of the SIM card  2 . Because the switch contact  39  is symmetric about the vertical plane through the center line L—L, forces within the switch contact  39  are evenly distributed, when the upper contact portion  340  is depressed, contributing to a longer useful life of the switch member  30 . 
     FIGS. 7 and 8 show another embodiment of the invention. The SIM card connector  1 ′ is similar to the earlier-described connector  1  except that the switch member  30 ′ of the SIM card connector  1 ′ has a hook-shaped switch contact  36  with upper and lower contact portions  360 ,  361  instead of the planar portion  331  and the upper and lower contact branches  34 ,  35  of the previous embodiment. The upper and the lower contact portions  360 ,  361  are vertically aligned and respectively symmetric about a vertical plane passing through a longitudinal center line. When a card  2  is inserted into the SIM card connector  1 ′, it depresses the upper contact portion  360 , causing the lower contact portion  361  to contact the PCB  3  and to engage with the switch trace  301  of the PCB  3  to establish an electrical connection therebetween. The establishment of this connection signals full insertion of the SIM card  2  into the SIM card connector  1 ′. The switch contact  36  has a longer useful life since upper and lower contact portions  360 ,  361  are symmetric about a vertical plane passing through a longitudinal center line of the switch member  30 ′, leading to evenly distributed forces in the switch contact  36  when it is subject to pressure by the inserted card  2 . 
     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.