Detection switch structure and connector having the same

A detection switch for detecting when a card is inserted in to a connector. The detection switch includes a housing, a shell, a card receiving passageway, and a detection switch. The shell is disposed on and covers the housing. The card receiving passageway is arranged between the housing and the shell. The detection switch detects when the card is inserted into the card receiving passageway and disposed along a side of the card connector. The detection switch includes a fixed contact secured to the housing, and a movable contact extending from the shell and configured to (1) contact the fixed contact when the card is not inserted in the card receiving passageway and (2) release from contact with the fixed contact when the card is inserted into the card receiving passageway.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit under 35 U.S.C. §119(a)-(d) of Japanese Patent Application No. 2010-278433, filed on Dec. 14, 2010.

FIELD OF THE INVENTION

The invention relates to a detection switch and, in particular, to a detection switch having a metal fixed contact and a metal movable contact that release from contact when a card is inserted in to a connector.

BACKGROUND

Conventionally, a card connector for receiving a card such as a memory card, a SIM (Subscriber Identity Module) card, or the like generally has a detection switch for detecting insertion of such a card.

For instance, JP 2002-324629 A discloses a card socket having a pair of contact members included in a detection switch for detecting the insertion of a card. In this card socket, when the card is inserted into the card socket, an edge corner portion of the card abuts a slant portion of one of the contact members. One of the contact members is displaced, a first contact of the contact member comes into wiping contact with a second contact of the other contact portion, and then the detection switch turns on. Accordingly, the insertion of the card can be detected.

Additionally, JP 2006-66281 A discloses a coaxial connector with a switch having a switch mechanism disposed in an insulating housing. The switch mechanism is composed of a connection plate and a changeover spring. The connection plate includes a secured portion secured to the housing, a flat plate-shaped contact portion extending from the secured portion, and a connecting portion connected to a circuit board. In addition, the changeover spring is provided with a secured portion secured to the housing, an elastic arm portion extending from the secured portion, a contact piece extending from the elastic arm portion to be in contact with the contact portion, and a connecting portion connected to the circuit board extending from the secured portion.

The contact piece of the changeover spring is in contact with the flat plate-shaped contact portion of the connection plate, when a mating pin is not inserted into the housing. Furthermore, as to the contact piece of the changeover spring, when the mating pin is inserted into the housing, the mating pin causes the contact piece to move apart from the flat plate-shaped contact portion of the connection plate, so that contact is released.

Moreover, JP 2008-299854 A discloses a mounting socket having a detection switch, for a memory card and a SIM card. The detection switch is integrally formed with an upper metal housing and a lower metal plate sandwiching the socket body from top and bottom. The detection switch is provided with an elastic bending piece extending from the upper metal housing, and a vertical contact projection extending from the lower metal plate to be in contact with the elastic bending piece. The elastic bending piece is in contact with the vertical contact projection, when the memory card or the SIM card is not inserted into the socket. When the card is inserted into the socket, the card displaces the elastic bending piece upward to move apart from the vertical contact projection, so that the contact state is released. Accordingly, the insertion of the card is detected.

As conventionally employed, however, the card socket described in JP 2002-324629 A, the coaxial connector with a switch described in JP 2006-66281 A, and the mounting socket for the memory card and the SIM card described in JP 2008-299854 A have the following problems.

That is, in a case of the card socket described in JP 2002-324629 A, since the first contact of one of the contact members is in close contact with the second contact of the other thereof at the time of detecting the insertion of the card, greater contact displacement is necessary when switching. This poses a problem in that downsizing of the card socket is difficult.

Besides, in a case of the coaxial connector with a switch described in JP 2006-66281 A, the contact between the contact piece of the changeover spring and the flat plate-shaped contact portion of the connection plate forms a line-surface contact between a line in the plate-thickness direction of the contact piece and a surface of the flat plate-shaped contact portion. For this reason, there is a problem that the Hertz stress is low at the time of contact.

If the Hertz stress is low, then the contact force between the contact piece and the flat plate-shaped contact portion is insufficient. Therefore, the contact force needs to be increased in order to improve the contact reliability.

In order to improve the contact reliability, the contact piece needs to be made larger by increasing the thickness of the contact piece or the like. This poses a problem in that the connector itself becomes bigger in size. Furthermore, when the contact piece is supported by the housing, with the contact force being increased by the contact piece, the housing relaxes the stress at the time of the reflow soldering connection. This causes a problem that the housing changes its shape significantly. Hence, the increased Hertz stress is desirably made higher to ensure the contact force between the contact piece and the contact portion, even in the decreased load placed by the contact piece.

Moreover, in a case of the mounting socket for the memory card and the SIM card described in JP 2008-299854 A, the contact between the elastic bending piece and the vertical contact projection forms a surface-surface contact or a surface-line contact between the surface of the elastic bending piece and the surface of the vertical contact projection. For this reason, there is a problem that the Hertz stress is low at the time of contact.

SUMMARY

Accordingly, the present invention has been made in view of the above problems, and has an object, inter alia, to provide a detection switch for a connector, in which downsizing can be achieved without the need of wiping at the time of contact, a larger Hertz stress is obtainable, and the contact reliability is high.

The detection switch is used to detect when a card is inserted in to a connector. The detection switch includes a housing, a shell, a card receiving passageway, and a detection switch. The shell is disposed on and covers the housing. The card receiving passageway is arranged between the housing and the shell. The detection switch detects when the card is inserted into the card receiving passageway and disposed along a side of the card connector. The detection switch includes a fixed contact secured to the housing, and a movable contact extending from the shell and configured to (1) contact the fixed contact when the card is not inserted in the card receiving passageway and (2) release from contact with the fixed contact when the card is inserted into the card receiving passageway.

DETAILED DESCRIPTION OF THE EMBODIMENT(S)

A connector1shown inFIG. 1toFIG. 10is mounted on a circuit board (not shown) and receives a card C (an object to be detected) such as a memory card, a SIM card, or the like. The connector1receives the card C, thereby achieving an electrical connection between the card C and the circuit board.

The connector1includes an insulating housing10, multiple metal contacts20, a metal shell30, a detection switch40, a cam mechanism70, and a card removal detection switch80.

Referring toFIG. 1toFIG. 3, the housing10is configured to receive the card C from the front side (lower side inFIG. 2). The housing10is formed in a substantially rectangular shape extending in the width direction (left-right direction inFIG. 2andFIG. 5) and in the length direction by molding an insulating resin. The housing10includes a left-side wall11having therein an insertion guiding surface12for the card C, as shown inFIG. 1andFIG. 6. A card receiving passageway13is arranged between the housing10and the shell30(a planar portion31) covering the housing10. When the card C is inserted into the card receiving passageway13, the insertion guiding surface12of the left-side wall11guides the left-side surface of the card C and an inner side of the a side surface32of the shell30guides the right-side surface of the card C.

The multiple contacts20are disposed to form two rows in the width direction of the housing10at the front side of the housing10, as shown inFIG. 3,FIG. 4,FIG. 5, andFIG. 10. Each contact20includes (1) a contact portion21for contact with a conductive pad C1(seeFIG. 3) disposed on the rear surface of the card C, and (2) a board connector22for connecting to the circuit board. Each contact20is formed by stamping and forming a conductive metal plate. When the card C is inserted into the card receiving passageway13, the contact portion21comes into contact with the conductive pad C1provided on the rear surface of the card C and becomes electrically conductive.

Additionally, the shell30is mounted on the housing10to cover at least a part of the housing10. The shell30includes a planar surface portion31covering the top surface of the housing10, a pair of side surfaces32covering both side surfaces in the width direction of the housing10, and a rear surface portion33covering the rear surface of the housing10. The planar surface portion31extends in the width and length directions of the housing10. Each of the side surfaces32extends downwardly from each side surface in the width direction of the planar surface portion31. In addition, the rear surface portion33extends downwardly from the rear surface in the length direction of the planar surface portion31. The shell30is formed by stamping and forming a metal plate. Specifically, a cam rod pushing piece35having a cantilever shape for pushing down the cam rod (not shown) of a cam mechanism70, to be described later, at the front left end of the planar surface portion31.

Furthermore, the detection switch40is provided for detecting whether or not the card C is inserted into the card receiving passageway13of the housing10, and is disposed at the rear right side of the card connector1, as shown inFIG. 1toFIG. 5. The detection switch40includes a metal fixed contact50, and a metal movable contact60, which are in contact with each other, when the card C is not inserted into the card receiving passageway13, as shown inFIG. 4,FIG. 13A, andFIG. 13B. When the card C is inserted into the card receiving passageway13, the movable contact60is driven to release the contact state between the movable contact60and the fixed contact50, as shown inFIG. 17AandFIG. 17B. In this manner, it is detected the insertion of the card C is completed. In this situation, the contact between the fixed contact50and the movable contact60is achieved, as specifically shown inFIG. 13A, by bringing a corner portion53of the fixed contact50and one surface62aof the movable contact60into contact with each other. Hereinafter, the detailed structures of the fixed contact50and the movable contact60will be described.

The fixed contact50is formed by stamping and forming a metal plate, and is secured to the housing10by insert molding, as shown inFIG. 11andFIG. 12. The fixed contact50includes a secured portion51to be secured to the housing10, as shown inFIG. 11andFIG. 12. The secured portion51is formed to have a flat-plate shape extending in the width and length directions of the housing10. In addition, the fixed contact50includes a fixed contact piece52extending outward and obliquely upward in the width direction from the side portion of the width direction, as specifically shown inFIG. 13AandFIG. 13B. Furthermore, the leading end of the fixed contact piece52includes a trimmed surface54made by stamping the metal plate, and an inclined surface55is formed from the trimmed surface54to the upper surface of the fixed contact piece52. Referring now toFIG. 13A, the rear side lower corner out of four corners formed in the trimmed surface54corresponds to the corner portion53to be in contact with one surface62aof the movable contact piece61in the movable contact60.

Moreover, the movable contact60has a movable contact piece61having a cantilever shape extending rearwardly from the side surface32of the shell30, as shown inFIG. 7,FIG. 13A,FIG. 13B,FIG. 14, andFIG. 15. The movable contact piece61includes a extension61aextending rearwardly in a free state from the side surface32, and a contact arm section61bextending obliquely inwardly in the width direction from the rear end of the extension61a.

A contact projection portion62having one surface62ato be in contact with the corner portion53of the fixed contact50is disposed at the lower portion of the contact arm section61b. One surface62aof the contact projection portion62is present at the inside of the contact projection portion62. Referring toFIG. 13B, a curved portion63, which is brought into contact with the linear side surface of the card C, when the insertion of the card C into the card receiving passageway13is completed, is arranged at the leading end of the contact arm section61bof the movable contact piece61.

In addition, the cam mechanism70makes it possible to eject the card with a so-called push-push action, and has a known structure. Therefore, the description thereof will be omitted. Furthermore, the card removal detection switch80detects a state where the card C inserted into the card receiving passageway13is removed. The card removal detection switch80is disposed at the rear end portion of the card connector1, as shown inFIG. 1toFIG. 5. The card removal detection switch80includes a first switch piece81extending from the rear surface portion33of the shell30; and a second switch piece82brought into contact with the first switch piece81when the card C is removed. Referring toFIG. 15, the second switch piece82is secured to the housing10. When the insertion of the card C into the card receiving passageway13is completed, the second switch piece82is spaced apart from the first switch piece81, as shown inFIG. 2. When the card C is moved rearwardly in order to remove the card C, the second switch piece82is brought into contact with the first switch piece81. In this manner, the removal of the card is detected.

Next, referring toFIG. 17AandFIG. 17B, the action of the detection switch40will be described in detail.

Firstly, as shown inFIG. 17A, when the card C is not inserted into the card receiving passageway13, one surface62aof the contact projection portion62included in the movable contact60is in contact with the corner portion53of the fixed contact50. The contact force between one surface62aand the corner portion53is ensured by an elastic force of the movable contact piece61. In this state, the detection switch40is switched on, and it means that insertion of the card C has not been carried out.

In this situation, the contact between the fixed contact50and the movable contact60is achieved by bringing the corner portion53of the fixed contact50and one surface62aof the movable contact60into contact with each other. Accordingly, the wiping contact is not needed when the fixed contact50and the movable contact60are in contact with each other. It is therefore possible to provide a detection switch40, in which downsizing thereof can be achieved, a large Hertz stress is obtainable with a point-surface contact being achieved, and contact reliability is set high.

In addition, the connector1has the detection switch40, and the fixed contact50is secured to the housing10for receiving the card C, whereas the movable contact60extends from the metal shell30covering at least a part of the housing10. It is therefore possible to provide the connector1having the detection switch40with high contact reliability.

Furthermore, the fixed contact50is secured to the housing10, and has the flat plate-shaped secured portion51extending in the width and the length directions of the housing10and the fixed contact piece52extending outward and obliquely upward in the width direction from the side portion of the width direction. On the other hand, the movable contact60has the cantilever-shaped movable contact piece61extending obliquely inwardly in the width direction from the side surface32of the shell30. Then, the contact between the fixed contact50and the movable contact60is achieved by the corner portion53of the fixed contact piece52and one surface62aof the movable contact piece61coming into contact with each other. Accordingly, it is possible to obtain the fixed contact50and the movable contact60for achieving the contact between the corner portion53and one surface62awith a simple structure. Moreover, since the movable contact60has the cantilever-shaped movable contact piece61, it is possible to ensure a reliable contact force when the corner portion53of the fixed contact50and one surface62aof the movable contact60are in contact with each other.

Additionally, the fixed contact50is formed by stamping and forming a metal plate, so the corner portion53of the fixed contact piece52is arranged at a corner of the trimmed surface54formed by stamping the metal plate. This allows the corner portion53of the fixed contact piece52to be formed with ease when the fixed contact50is formed.

Then, from the contact state between the fixed contact50and the movable contact60, the card C is inserted into the card receiving passageway13, as shown inFIG. 17B. After that, the curved surface formed at a front-end corner rim of the card C comes into contact with an inner surface of the contact arm section61bincluded in the movable contact piece61of the movable contact60. This is because the contact arm section61bextends obliquely, inwardly in the width direction from the rear end of the extension61aof the movable contact piece61, and protrudes into the card receiving passageway13.

Subsequently, as the insertion of the card C proceeds, the contact arm section61bis displaced outward in the width direction along the curved surface of the card C. This causes one surface62aof the contact projection portion62to move apart from the corner portion53of the fixed contact50, and releases the contact state between the movable contact60and the fixed contact piece52. In this state, the detection switch40is switched off, and it means that the insertion of the card C is detected.

As insertion of the card C further proceeds and insertion of the card C is completed, the curved portion63of the movable contact60comes into contact with the linear side surface of the card C. Contact force of the curved portion63with the side surface of the card C is ensured by a spring force of the movable contact piece61.

Specifically, when the card C is inserted into the card receiving passageway13, conductive pads C1arranged on the rear surface of the card C are in contact with the contact portion21of the contacts20, respectively, so that the card C and the circuit board are electrically connected through the respective contacts20.

In contrast, when the card C is removed from the card receiving passageway13, and the card C is moved toward the read side, the action of a spring, not shown, biases the card C to the front side, thereby enabling the card C to be removed from the card receiving passageway13. In the removing process of the card C, the movable contact60operates in a reverse manner of the insertion process of the card C. When the removal of the card C is completed, one surface62aof the contact projection portion62included in the movable contact60is brought into contact with the corner portion53of the fixed contact50again.

The embodiments of the present invention have been described heretofore. However, it will be appreciated that the present invention is susceptible of modification, variation and change without limiting to this.

An example is that the detection switch40is applicable not only to a case where insertion of the card C is detected, but also to a situation where the insertion of a mating connector to be mated with the connector is detected.

Additionally, the detection switch40may not be provided with the connector having the housing and the shell.

The detection switch40may take any structure design as long as the contact, between the movable contact and the fixed contact, releases after the movable contact is moved when the object to be detected engages the movable contact.

Furthermore, the contact between the fixed contact and the movable contact may be achieved by one surface of the fixed contact coming into touch with the corner portion of the movable contact.