WO2004068391A1

WO2004068391A1 - Memory card connector with improved terminals

Info

Publication number: WO2004068391A1
Application number: PCT/US2004/002943
Authority: WO
Inventors: Huang San-Shan; Zhao Lei; Sun Zhao You
Original assignee: Molex Incorporated
Priority date: 2003-01-30
Filing date: 2004-01-30
Publication date: 2004-08-12
Also published as: WO2004068391B1; CN2645261Y

Abstract

A memory card connector includes an insulative housing having a mating face and a circuit board mounting face (32) with at least one terminal-receiving passage (34) having an opening in the mating face of the housing. A terminal is received in the terminal-receiving passage and includes an elongated spring arm (42) cantilevered in the passage and defining a longitudinal axis of the arm. A dome-shaped contact portion (50) is located near a distal end of the cantilevered spring arm projecting through the opening in the mating face of the housing and defining an oval-shaped convex contact surface. The oval-shaped convex contact surface has an elliptical base at the spring arm and defines a major axis of the ellipse generally parallel to the longitudinal axis of the arm and a minor axis generally perpendicular to the longitudinal axis.

Description

MEMORY CARD CONNECTOR WITH IMPROVED TERMINALS

Field of the Invention;

This invention generally relates to the art of electrical connectors and, particularly, to a memory card connector having terminals with improved dome-shaped contact portions.

Background of the Invention:

Memory cards are known in the art and contain intelligence in the form of a memory circuit or other electronic program. Some form of card reader reads the information or memory stored on the card. Such cards are used in many applications including mobile telephones which are actuated and permit data access after identifying an identification code stored on a SIM (subscriber identification module) card. The SIM card has a conductive face with an array of contacts, and the mobile phone has a SIM card connector with terminals for electrical connection with the contacts of the SIM card to ensure the subscriber identification confirmation and provide wireless communication service.

FIG. 1 shows a conventional SIM card connector, generally designated 10, which includes an insulative housing, generally designated 12, mounting a plurality of conductive terminals, generally designated 14. The housing has a mating face 12a and a circuit board mounting face 12b for mounting the SIM card connector on a printed circuit board 16. Mating face 12a has a plurality of through holes 12c. Each terminal 14 has an elongated spring arm 14a which terminates in an angled contact portion 14b which projects through hole 12c in mating face 12a of the housing. Each terminal 14 also includes a foot portion 14c for connection to an appropriate circuit trace 18 on the printed circuit board.

In essence, elongated spring arm 14a of each terminal 14 defines a longitudinal axis of the arm. Contact portion 14b is triangulated to define two angled surfaces as is clearly seen in FIG. 1. When a SIM card is engaged with the terminals of connector 10 in the direction of arrow "A", the edge of the card engages one of the angled surfaces and depresses or biases contact portion 14b downwardly into the respective hole 12c in the mating face of the insulative housing. In other words, movement of the card in the direction of arrow "A" is generally parallel to the longitudinal axis of spring arm 14a of the terminal, and engagement of the card with the angled contact surface easily biases the contact portion downwardly.

However, problems are encountered when the SIM card is moved against contact portion 14b closer to a direction indicated by arrow "B" which is generally perpendicular to the longitudinal axis of the spring arm of the terminal. The card will engage the sharp side edge of contact portion 14b and cause the contact portion to bend, distort or otherwise become permanently damaged. In addition, this can cause disruption of the connection between the foot portion 14c of the terminal and the circuit trace 18 on the printed circuit board. Attempts have been made to form contact portion 14b more in the shape of a dome, but this causes the contact portions to be unduly wide which, in turn, increases the pitch or spacing between the terminals and results in an unduly large connector. The present invention is directed to solving these various problems.

Summary of the Invention: An object, therefore, of the invention is to provide a memory card connector of the character described, with terminals having improved dome-shaped contact portions.

In the exemplary embodiment of the invention, the connector includes an insulative housing having a mating face and a circuit board mounting face, with at least one terminal- receiving passage having an opening in the mating face of the housing. A terminal is received in the passage and includes an elongated spring arm cantilevered in the passage and defining a longitudinal axis of the arm. A dome-shaped contact portion is located near a distal end of the cantilevered spring arm and projects through the opening in the mating face of the housing. The dome defines an oval-shaped convex contact surface which has an elliptical base at the spring arm, thereby defining a major axis of the ellipse generally parallel to the longitudinal axis of the arm and a minor axis generally perpendicular to the arm.

According to one aspect of the invention, the oval-shaped convex contact surface has a steep-sloped contact face on a side thereof facing in a direction generally parallel to the longitudinal axis of the elongated spring arm. A gentle-sloped contact face is provided on a side of the oval-shaped convex contact surface facing in a direction generally perpendicular to the longitudinal axis of the elongated spring arm. The contact faces are generally triangularly- shaped, with corners of the triangles coincident with an apex of the convex contact surface. As disclosed herein, a pair of the steep-sloped contact faces are located at diametrically opposite sides of the oval-shaped convex contact surface and facing in a direction generally parallel to the longitudinal axis of the elongated spring arm. A pair of the gentle-sloped contact faces are located at diametrically opposite sides of the oval-shaped convex contact surface and facing in a direction generally perpendicular to the longitudinal axis. Smooth transition face sections smoothly join the steep-sloped contact faces and the gentle-sloped contact faces.

According to another object of the invention, the terminal is generally U-shaped to define a first leg joined to a second leg by a curved spring section. The first leg forms the elongated spring arm of the terminal. The second leg is connected to the circuit board and includes a contact foot for connection to an appropriate circuit trace on the board. The second leg includes a mounting post securely fixed in a mounting hole in the insulative housing.

Another feature is the provision of complementary interengaging anti-overstress means between the insulative housing and the elongated spring arm at the distal end of the arm to limit the extent to which the dome-shaped contact portion can project through the opening in the mating face of the housing.

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 a conventional SIM card connector of the prior art and as described in the "Background", above;

FIG. 2 is a perspective view of a SIM card connector according to the invention; FIG. 3 is an exploded perspective view of the connector of the invention; FIG. 4 is a bottom perspective view showing the underside of the connector housing; FIG. 5 is an enlarged top plan view of one of the terminals of the connector; and FIG. 6 is a vertical section, on an enlarged scale, taken generally along line 6-6 of FIG. 2, in conjunction with a SIM card depressing one of the terminals.

Detailed Description of the Preferred Embodiment: Referring to the drawings in greater detail, and first to FIGS. 2 and 3, the invention is embodied in a memory card connector, generally designated 20, which, particularly, is a subscriber identification module (SIM) card connector. The connector is capable of electrically connecting a SLM card 22 (FIG. 6) and a printed circuit board 24. The SLM card has an array of contacts on the bottom surface thereof. As seen in FIG. 3, circuit board 24 has an array of circuit traces or contact pads 26 on a top surface 24a of the board.

Connector 20 includes a dielectric or insulative housing, generally designated 28, which includes a mating face 30 and a circuit board mounting face 32, with a plurality of terminal- receiving passages 34 extending between the faces. Each through passage 34 includes an opening 34a in mating face 30 of the housing. Referring to FIG. 4 in conjunction with FIGS. 2 and 3, each terminal-receiving passage

34 has an offset portion 34b which is open at the bottom of the housing. An angled surface 34c is located at one end of each offset portion 34b. A pair of mounting holes 36 are located at opposite sides of each offset portion 34b and extend into the housing. A cut-out 34d is formed in each through passage 34 diametrically opposite angled surface 34c. Finally, a notch 38 is formed in board-mounting face 32 in a side edge of housing 28 communicating with each through passage 34.

Referring to FIG. 5 in conjunction with FIGS. 2 and 3, insulative housing 28 mounts a plurality of conductive terminals, generally designated 40. As seen in the drawings, there are six contact pads 26 (FIG. 3) on circuit board 24 and a corresponding six through tenninal-receiving passages 34 in housing 28, and there are provided a corresponding six conductive terminals 40. The terminals may be stamped and formed of conductive sheet metal material.

Each terminal 40 is generally U-shaped to define a first leg 42 joined to a second leg 44 by a curved spring section 46. First leg 42 of the U-shaped terminal defines an^' elongated spring arm of the terminal. Second leg 42 forms a base of the terminal, with the elongated spring arm being bent back over the top of the base. The base of each terminal has a downwardly offset foot 48 for connection, as by soldering, to a respective one of the contact pads 26 on circuit board 24 as seen in FIG. 2. A dome-shaped contact portion, generally designated 50, is formed near a distal end of elongated spring arm 42 of each terminal. As seen clearly in FIG. 2, all of the dome-shaped contact portions project upwardly through openings 34a of through terminal- receiving passages 34. An anti-overstress bar 52 is located at the distal end of the elongated spring arm of each terminal, for purposes described hereinafter. A pair of mounting posts 54 project upwardly from opposite sides of base 44 of each terminal.

With the above descriptions, in assembly, terminals 40 are inserted into the through the terminal-receiving passages 34 of housing 28 through the bottom (FIG. 4) of the housing in the direction of arrows "C" shown in FIG. 6. During insertion, mounting posts 54 of the terminals are inserted into mounting holes 36 (FIG. 4) in the bottom of the housing and teeth at opposite edges of the mounting posts bite into the dielectric material of the housing within the mounting holes. This securely mounts the terminals in the underside of the housing, with the dome-shaped contact portions 50 of the terminals projecting through openings 34a at the top of the housing. Feet 48 of the terminals become located in notches 38 at the bottom of the housing so that the feet are in position for solder connection to contact pads 26 of circuit board 24. Anti-overstress bars 52 at the distal ends of elongated spring arms 42 of the terminals engage anti-overstress surfaces 60 (FIG. 4) of the housing to limit the extent to which the dome-shaped contact portions 50 can project through the openings in mating face 30 of the housing. Curved spring sections 46 are located in offset portions 34b (FIG. 4) of passages 34, and, as seen with the left-hand terminal in FIG. 6, there is a space 62 provided wherein the terminal is in an unstressed condition, whereby the curved spring portion 46 can compress into that space when the terminal is engaged by a SIM card as shown by the right-hand terminal in FIG. 6. The terminals have wing portions 64 which project outwardly from opposite edges of base 44 for engaging the opposite side walls of offset portions 34b of the passages to stabilize the terminals within the housing.

Referring particularly to FIG. 5 but in conjunction with FIGS. 2, 3 and 6, dome-shaped contact portion 50 of each terminal 40 has a very unique configuration. Before proceeding, it can be seen clearly in FIG. 5 that spring arm 42 of each terminal is elongated and, thereby, defines a longitudinal axis 66 of the arm. As seen in FIG. 6, this elongated arm (along with the dome-shaped contact portion) becomes cantilevered within through passage 34 of the housing. With that understanding, it clearly can be seen in FIG. 5 that the dome-shaped contact portion 50 is oval-shaped and defines an elliptical base 68. As clearly seen, the elliptical base is oriented so that its major or long axis is generally parallel to longitudinal axis 66 of spring arm 42. The narrow or minor axis of the elliptical base 68 is generally perpendicular to longitudinal axis 66 of the spring arm. In addition, the oval-shaped convex contact surface defined by the oval or elliptically-shaped contact portion is divided into a plurality of triangular or pie-shaped sections or segments.

In particular, a pair of escarped or steep-sloped contact faces 50a are located at diametrically opposite sides of the convex contact surface and face in a direction generally parallel to longitudinal axis 66 of elongated spring arm 42. A pair of gentle-sloped contact faces 50b are formed on opposite sides of the convex contact surface and face in a direction generally perpendicular to longitudinal axis 66 of the elongated spring arm. The respective steep-sloped contact faces 50a are separated from the gentle-sloped contact faces 50b by four smooth transition faces 50c. The steep-sloped faces are larger or wider than the other faces to present wider surfaces for proper engagement by the SLM card. The results of the overall configuration of the dome-shaped contact portions 50 have a number of advantages.

First, with the long or major axis of elliptical base 68 being in line with longitudinal axis 66 of elongated spring arm 42 as shown clearly in FIG. 5, and with the narrow or minor axis of the elliptical base being generally perpendicular to the longitudinal axis, the overall width of the terminal is maintained as narrow as possible. This is in contrast to a situation where the convex contact surface provided by the dome-shaped contact portion would be circular or define a circular base. The result is that the terminals can be at as close a pitch or spacing as possible.

Second, with the escarped steep-sloped contact faces 50a being in line with or facing in the direction of the longitudinal axis 66 of the terminal spring arm, significant forces can be involved to make the terminal as robust as possible without distorting the terminal, because, as seen in FIG. 6, SIM card 22 is inserted normally or properly in the direction of arrow "A". This direction is in line with the axis of the longitudinal spring arm and, thereby, can accept significant forces without buckling. On the contrary, contact faces 50b at the sides of the dome- shaped contact portion have a more gentle slope should forces by applied in a direction generally perpendicular to longitudinal axis 66. The angled or sloped contact faces 50b allow the contact portion to be easily depressed rather than distorted, and the gentle slope of the contact faces reduces the engaging forces as much as possible. 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.

Claims

CLAIMS:What is claimed is:

1. A memory card connector, comprising: an insulative housing including a mating face and a circuit board mounting face with at least one terminal-receiving passage having an opening in the mating face of the housing; and a terminal received in said terminal-receiving passage and including an elongated spring arm cantilevered in the passage and defining a longitudinal axis of the arm, a dome-shaped contact portion near a distal end of the cantilevered spring arm projecting through the opening in the mating face of the housing and defining an oval-shaped convex contact surface, the oval-shaped convex contact surface having an elliptical base at the spring arm and defining a major axis of the ellipse generally parallel to the longitudinal axis of the arm and a minor axis generally perpendicular to the longitudinal axis, and the oval-shaped convex contact surface having a steep-sloped contact face on a side thereof facing in a direction generally parallel to the longitudinal axis of the elongated spring arm and a gentle-sloped contact face on a side thereof facing in a direction generally perpendicular to the longitudinal axis of the elongated spring arm.

2. The memory card connector of claim 1 wherein said contact faces are generally triangularly-shaped with corners of the triangles coincident with an apex of the convex contact surface.

3. The memory card connector of claim 1 , including a pair of said steep-sloped contact faces at diametrically opposite sides of the oval-shaped convex contact surface and facing in a direction generally parallel to the longitudinal axis of the elongated spring arm.

4. The memory card connector of claim 3, including a pair of said gentle-sloped contact faces at diametrically opposite sides of the oval-shaped convex contact surface and facing in a direction generally perpendicular to the longitudinal axis of the elongated spring arm.

5. The memory card connector of claim 4, including smooth transition face sections smoothly joining said steep-sloped contact faces and said gentle-sloped contact faces.

6. The memory card connector of claim 1 wherein said terminal is generally U- shaped to define a first leg joined to a second leg by a curved spring section, the first leg forming said elongated spring arm, and the second leg being connected to the circuit board.

7. The memory card connector of claim 6 wherein said second leg of the U- shaped terminal includes a mounting post securely fixed in a mounting hole in the insulative housing.

8. The memory card connector of claim 6 wherein said second leg includes a contact foot for connection to an appropriate circuit trace on the circuit board.

9. The memory card connector of claim 1 , including complementary interengaging anti-overstress means between the insulative housing and the elongated spring arm at the distal end of the arm to limit the extent to which the dome-shaped contact portion can project through the opening in the mating face of the housing.

10. A memory card connector, comprising: an insulative housing including a mating face and a circuit board mounting face with at least one terminal-receiving passage having an opening in the mating face of the housing; and a generally U-shaped terminal received in said terminal-receiving passage and defining a first leg joined to a second leg by a curved spring section, said first leg forming an elongated spring arm cantilevered in the passage and defining a longitudinal axis of the arm, said second leg being connected to the circuit board, a dome-shaped contact portion near a distal end of the cantilevered spring arm projecting through the opening in the mating face of the housing and defining an oval-shaped convex contact surface, the oval-shaped convex contact surface having an elliptical base at the spring arm and defining a major axis of the ellipse generally parallel to the longitudinal axis of the arm and a minor axis generally peφendicular to the longitudinal axis, and the oval-shaped convex contact surface having a pair of steep-sloped contact faces at diametrically opposite sides thereof and facing generally parallel to the longitudinal axis of the elongated spring arm and a pair of gentle-sloped contact faces at diametrically opposite sides of the oval-shaped convex contact surface and facing in a direction generally peφendicular to the longitudinal axis of the elongated spring arm, with four smooth transition face sections smoothly joining said steep-sloped contact faces and said gentle-sloped contact faces.

11. The memory card connector of claim 10 wherein said contact faces are generally triangularly-shaped with comers of the triangles coincident with an apex of the convex contact surface.

12. The memory card connector of claim 10 wherein said second leg of the U- shaped terminal includes a mounting post securely fixed in a mounting hole in the insulative housing.

13. The memory card connector of claim 12 wherein said second leg includes a contact foot for connection to an appropriate circuit trace on the circuit board.

14. The memory card connector of claim 10, including complementary interengaging anti-overstress means between the insulative housing and the elongated spring arm at the distal end of the arm to limit the extent to which the dome-shaped contact portion can project through the opening in the mating face of the housing.

15. A memory card connector, comprising: an insulative housing including a mating face and a circuit board mounting face with at least one terminal-receiving passage having an opening in the mating face of the housing; and a terminal received in said terminal-receiving passage and including an elongated spring arm cantilevered in the passage and defining a longitudinal axis of the arm, a dome-shaped contact portion near a distal end of the cantilevered spring arm projecting through the opening in the mating face of the housing and defining an oval-shaped convex contact surface, and the oval-shaped convex contact surface having an elliptical base at the spring arm and defining a major axis of the ellipse generally parallel to the longitudinal axis of the arm and a minor axis generally peφendicular to the longitudinal axis.