Card connector

In a card connector having a push-push type eject mechanism, a cam lever is retained by a cam lever retaining member made from a cantilevered leaf spring, which in turn is retained by a leaf spring formed in a metal cover. The metal cover along with the housing forms a card accommodating portion. The cam lever is therefore doubly retained by the cam lever retaining member and the leaf spring and thus prevented against coming off. This arrangement also enhances a clicking feel of the eject mechanism during the insertion and ejection of the card.

This application is based on patent application Ser. No. 2001-032755 filed Feb. 8, 2001 in Japan, the content of which is incorporated hereinto by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a card connector mounted on electronic devices, such as cellular phones, telephones, PDAs (personal digital assistants), portable audio devices and cameras, and more particularly to a structure of a compact mechanism for reliably locking an IC card in the card connector.

2. Description of the Related Art

In electronic devices such as cellular phones, telephones, PDAs and cameras, a variety of functions are added by inserting an IC card with a built-in CPU or IC memory, such as a SIM (subscriber identity module) card, an MMC (multimedia card), an SD (secure digital) card, a Memory Stick (tradename) and a Smart Media (tradename).

A card connector structure for removably accommodating such an IC card has a plurality of contact terminals formed from metal leaf springs in a connector housing which are brought into contact with a plurality of contact pads formed on a front or back surface of the inserted IC card to electrically connect the IC card to the electronic device on which the connector is mounted. The contact pads of the IC card include a power supply pad connected to a power supply line and a plurality of signal pads for transferring a variety of signals. These pads are connected through the contact terminals of the card connector to the associated power supply circuit and a variety of signal processing circuits of the electronic device.

Many of the card connectors mounted on these electronic devices have an eject mechanism to eject the inserted card from the connector.

The conventional eject mechanisms are available in the following types:One in which an insertion depth of the card is so set that the rear end of the inserted card protrudes from a card insertion opening and can be held by fingers of the user for withdrawing; andOne in which an eject button provided near the card insertion opening is pressed by the user after the use of the card to activate the eject mechanism to eject the card.

In the former type, however, the card connector is required to have a dimension such that the rear end of the card protrudes from the connector for gripping by fingers. Not only does this impair the appearance of the connector but it also increases a chance of the card being damaged by external impacts and requires a large load to withdraw the card.

The latter type, on the other hand, has difficulty in locating the eject button at an appropriate position due to a limited space and also has a problem of the eject button impairing the appearance and hindering a size reduction.

To solve these problems Japanese Patent Application Laid-open No. 2000-251025 has been proposed. An exploded view of the proposed structure is shown in FIG.12. With this conventional technology, a push-push type card ejection (which activates the card eject mechanism by pushing the inserted IC card again to eject it) is realized by using a heart-shaped cam and a cam lever.

InFIG. 12, the conventional eject mechanism has an eject member100with a triangular card abutment portion101against which a triangular cut-off corner portion of the card abuts, a coil spring103interposed between a housing lower plate102and the eject member100, a guide groove104formed in the housing lower plate102to guide the movement of the eject member100, a heart cam105formed in the housing lower plate102, lever guide grooves107a,107bformed in the housing lower plate102around the heart cam105to guide the movement of a cam lever108, and the cam lever108having one of its end secured to the eject member100and the other end moving through the lever guide grooves107.

In this eject mechanism, when a card is inserted into the connector, the eject member100is pushed by the card through the card abutment portion101and is thus moved against the force of the coil spring103toward the rear of the connector. At this time, a front end portion108aof the cam lever108moves along the lever guide groove107auntil it is locked at a recessed locking portion105aof the heart cam105. Now, the card is held immovable in the connector with the contact pads of the card in contact with the contact terminals of the connector.

When the card is to be ejected, the user slightly pushes the inserted card rearward. This disengages the cam lever108from the locking portion105aof the heart cam105, allowing the front end portion108aof the cam lever108to be driven forwardly of the connector along the lever guide groove107bby the recovering force of the coil spring103. The eject member100therefore moves forwardly causing the card to be ejected by the card abutment portion101of the eject member100.

If the eject mechanism is provided, for example, in a side wall of the connector housing, there would be a problem that the cam lever108may easily come off since the end of the cam lever108opposite the front end portion108ais simply press-fitted into the eject member100.

This kind of card connector often employs a metal cover as an upper housing to reduce the thickness of the card and increase the strength of the housing. The metal cover has a ground terminal formed at one end thereof through which the metal cover is connected to a ground electrode of a printed circuit board to release a static electricity accumulated in the metal cover.

The card connector with the ground terminal formed on the metal cover has a problem that when it is desired to realize card connectors with different height (thickness) specifications or different standoff specifications, a plurality of metal covers, which are relatively large and expensive parts in the card connector, need to be prepared corresponding to these specifications (i.e., a plurality of metal covers with ground terminals of different heights must be prepared). This increases the manufacturing cost.

SUMMARY OF THE INVENTION

The present invention has been accomplished under these circumstances. It is an object of this invention to provide a card connector which reliably prevents a dislocation of the cam lever and enhances a clicking feel as the card is inserted and ejected.

Another object of the present invention is to provide a card connector which, when a stand-off specification changes, realizes a ground connection simply by modifying a small and inexpensive part to reduce the manufacturing cost.

According to one aspect of the present invention there is provided a card connector comprising: a connector housing having a plurality of contact terminals arranged therein; a metal cover covering the connector housing to form a card accommodating portion, the card accommodating portion being adapted to hold a card therein in such a way that a plurality of contact pads formed at a bottom of the card engage the contact terminals; an eject member having a heart-shaped cam element and grooves formed around the cam element, the eject member being adapted to move in a card insertion direction with respect to the connector housing as the card is inserted into the card accommodating portion and to move in a card ejection direction with respect to the connector housing in response to a card eject operation; a cam lever having one of its ends pivotally supported in the connector housing and the other end adapted to slide in the grooves around the cam element; a cam lever retaining member secured to the connector housing to bear on the cam lever; and a leaf spring formed in the metal cover to bear on the cam lever retaining member.

In this invention, the cam lever is retained by a cam lever retaining member made from a cantilevered leaf spring, which in turn is retained by a leaf spring formed in a metal cover. The cam lever is therefore doubly retained by the cam lever retaining member and the leaf spring. This arrangement reliably prevents a dislocation of the cam lever and enhances a clicking feel as the card is inserted and ejected.

In a preferred embodiment of this invention, the cam lever retaining member is formed from a conductive member and is grounded to a printed circuit board through its terminal end portion.

In a preferred embodiment of this invention, the conductive cam lever retaining member contacts the leaf spring formed in the metal cover, with its terminal end portion grounded to the printed circuit board. Therefore, static electricity that has built up in the metal cover can be released to a ground electrode through the cam lever retaining member. In this invention, because the connector is grounded to the printed circuit board through the terminal end portion of the cam lever retaining member, a variety of stand-off specifications can be dealt with simply by changing the length of the terminal end portion of the cam lever according to each of the stand-off specifications. The cam lever retaining member is small and inexpensive compared with the metal cover, so that the manufacturing cost of the card connector can be minimized in dealing with a variety of stand-off specifications.

According to another aspect of the present invention, there is provides a card connector comprising: a connector housing having a plurality of contact terminals arranged therein, the connector housing also having a heart-shaped cam element and grooves formed around the cam element; a metal cover covering the connector housing to form a card accommodating portion, the card accommodating portion being adapted to hold a card therein in such a way that a plurality of contact pads formed at a bottom of the card contact the contact terminals; an eject member adapted to move in a card insertion direction with respect to the connector housing as the card is inserted into the card accommodating portion and to move in a card ejection direction with respect to the connector housing in response to a card eject operation; a cam lever having one of its ends pivotally supported in the eject member and the other end adapted to slide in the grooves around the cam element; a cam lever retaining member secured to the connector housing to bear on the cam lever; and a leaf spring formed in the metal cover to bear on the cam lever retaining member.

In this another aspect of the present invention, the heart-shaped cam element is formed in the connector housing and the cam lever is pivotally supported at one end on the eject member and, at the other end, is slid around the cam element.

In this another aspect of the invention, too, the cam lever is retained by a cam lever retaining member made from a cantilevered leaf spring, which in turn is retained by a leaf spring formed in a metal cover. The cam lever is therefore doubly retained by the cam lever retaining member and the leaf spring. This arrangement reliably prevents a dislocation of the cam lever and enhances a clicking feel as the card is inserted and ejected.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Now, embodiments of the present invention will be described in detail by referring to the accompanying drawings.

FIG. 1shows a Memory Stick (tradename) as an example of an IC card10withFIG. 1Ashowing a contact pad surface of the card andFIG. 1Ba side surface of the card.

The IC card10has a cut-off corner portion11at one front corner to prevent its erroneous insertion. The card body10is formed in its front area with a plurality of recesses12, at the bottoms of which are arranged contact pads13that are connected to an internal memory circuit or control circuit of the card. The contact pads13are formed in a 10-pin configuration.

In the embodiment that follows, we will describe the present invention as applied to a connector for the IC card10described above by referring toFIG. 2to FIG.9.

FIG. 2is a perspective view showing an external construction of the card connector1.FIG. 3is a side view of the card connector.FIG. 4is a plan view showing an inner construction of the card connector1with the metal cover removed.FIG. 5is a side view of FIG.4.FIG. 6illustrates the eject mechanism in a card ejected state.FIG. 7shows the state of the eject mechanism when the card is pushed for loading.FIG. 8shows the state of the eject mechanism when the card is completely loaded.FIG. 9shows the state of the eject mechanism when the card is pushed for withdrawing.

The card connector1is mounted on electronic devices, such as cellular phones, PDAs, portable audio devices, cameras and so on. The card10is inserted into the connector1with its contact pad surface facing down.

The card connector1has a lower housing2and a metal cover3as an upper housing. The lower housing2is formed of an insulating material such as resin. The upper housing3is formed from a metal plate through sheet metal processing and functions as a cover body covering the lower housing2. The reason that the upper housing3is formed from a sheet metal, not from resin, is that metal is stronger than resin and thus can reduce the height of the connector.

The metal cover3comprises mainly an almost flat top plate20and left and right side plates21bent at right angle to the top plate20. One of the side plates21of the metal cover3is formed with a leaf spring22in a window23as by blanking. The leaf spring22constitutes an important part of this invention and thus will be detailed later.

The lower housing2, as shown in FIG.4and so on, has a bottom plate4, left and right side plates5rising from opposite sides of the bottom plate4, and a rear plate6situated at the rear ends of the bottom plate4and the side plates5. The side plates21of the metal cover3engage with the side plates5of the lower housing2. In this state the top plate20of the metal cover3and the bottom plate4, side plates5and rear plate6of the lower housing2combine to form an almost rectangular card accommodating portion7in which the card10is loaded. The card10is inserted from a card insertion opening8(FIG. 2) formed at the front of the upper and lower housings.

Inner walls of the left and right side plates5of the lower housing2are formed with guide rails (not shown) that guide side edges of the card10. The card10is inserted or withdrawn along the guide rails with its contact pad surface facing down.

A plurality (in this case,10) of contact terminals30are securely press-fitted into the bottom plate4of the lower housing2.

Each of the contact terminals30, as shown in FIG.2andFIGS. 4to6, is formed from a cantilevered metal leaf spring and has a terminal portion31to be soldered to an associated contact pad on a printed circuit board of the electronic device, a fixed portion32press-fitted into the bottom plate4of the lower housing2, and an elastically displaceable spring portion33. The spring portion33has at its front end an arc-shaped contact portion34that protrudes upwardly to come into contact with the contact pads13of the IC card10.

The card connector1has a so-called push-push type eject mechanism40in which the inserted card10is ejected forwardly by slightly pushing it rearwardly, i.e., to the far side, of the housing.

The eject mechanism40, as shown inFIG. 4toFIG. 9, includes an eject member42which is movable longitudinally of the lower housing2along a guide groove41formed in the bottom plate4of the lower housing2. The eject member42has a heart-shaped cam element (heart cam)50formed in an outer side wall thereof and also lever guide grooves51a-51cformed around the heart cam50. The eject mechanism40also includes a staple-shaped cam lever53having its one end53asupported in the lower housing2and the other end53badapted to slide along the lever guide grooves51a-51c, and a coil spring43(FIG. 4) interposed between the lower housing2(or metal cover3) and the eject member42.

The eject member42has a card abutment portion42athat abuts the cut-off corner portion11of the card10.

One end53aof the cam lever53is inserted in and rotatably supported by a hole6a(FIG. 6) formed in a side surface of the rear plate6of the lower housing2. The other end53bof the cam lever53is guided and slid along the lever guide grooves51a-51cformed around the heart cam50.

Since one end53aof the cam lever53is simply inserted in the hole6aformed in the lower housing2, a cam lever retaining member60is provided which holds the cam lever53from outside to prevent it from coming off and ensure a smooth sliding movement of the cam lever end53bin the lever guide grooves51a-51c.

In this case, the cam lever retaining member60is formed from a metal leaf spring and has a terminal end portion60ato be connected to a ground electrode pad of the printed circuit board, a plurality of press fit portions60bpress-fitted in the lower housing2, and an elastically displaceable spring portion60c. The press fit portions60bof the cam lever retaining member60are fitted under pressure into a plurality (in this case, four) of slots55formed in the side surface of the rear plate6of the lower housing2on both sides of the hole6aso that the cam lever retaining member60is supported like a cantilever. The spring portion60chas at its free end an arc-shaped lever engagement portion60dthat protrudes toward the cam lever53.

Since the cam lever retaining member60is elastically deformed by the sideways displacement of the cam lever53as the eject member42is moved, the side plate21of the metal cover3is formed with the window23set forth above to provide a clearance for the elastic deformation of the cam lever retaining member60.

In the window23of the metal cover3the leaf spring22is formed integral with the metal cover3by blanking to further bear on the cam lever retaining member60from outside. The leaf spring22is formed in the side plate21of the metal cover3to extend along the spring portion60cof the cam lever retaining member60. The leaf spring22is urged toward the cam lever retaining member60to press on it from outside.

In this eject mechanism40of the card connector1, before the card is inserted or when the card eject operation is completed, the eject member42is located at a predetermined position on the front side of the housing by the pulling force of the coil spring43, as shown in FIG.6. At this time, the front end53bof the cam lever53is situated in the lever guide groove51aof the eject member42.

When in this state the card10is inserted into the card connector1, the eject member42is pushed by the card through the card abutment portion42a. The eject member42is thus moved rearwardly of the connector against the force of the coil spring43. At this time, the front end53bof the cam lever53moves along the lever guide groove51buntil it finally abuts a groove end51don the lever guide groove51bside, as shown in FIG.7.

In this state, when the user stops pushing the card and releases it, the recovering force of the coil spring43moves the eject member42forwardly of the connector, causing the front end53bof the cam lever53to engage a recessed engagement portion50aof the heart cam50and become locked by it, as shown in FIG.8. Thus, the card10is held immovable with its contact pads13in contact with the contact terminals30of the connector.

When the card10is to be ejected, the inserted card10is pushed slightly rearwardly or to the far side. As a result, the eject member42moves rearwardly of the connector, unlocking the cam lever53from the engagement portion50aof the heart cam50and bringing the front end53bof the cam lever53into abutment with a groove end51eon a lever guide groove51cside, as shown in FIG.9.

In this state, when the user stops pushing and releases the card, the recovering force of the coil spring43moves the eject member42to the front side of the connector. As a result, the front end53bof the cam lever53moves along the lever guide groove51cuntil it finally returns to the original state of FIG.6.

In this way, the card10is ejected by the card abutment portion42aof the eject member42.

In this embodiment, the cam lever53is held from outside by the cam lever retaining member60formed from a cantilevered leaf spring, and the cam lever retaining member60is in turn held from outside by the leaf spring22which is formed in the metal cover3. That is, the cam lever53is retained doubly by the cam lever retaining member60and the leaf spring22. This arrangement, therefore, can not only reliably prevent the staple-shaped cam lever from getting dislocated but also enhance a clicking feel of the eject mechanism40during the card insertion/ejection process.

In this embodiment, the cam lever retaining member60of a conductive material (for example, metal) is formed with the terminal end portion60athrough which it can be grounded to the printed circuit board. The cam lever retaining member60contacts the leaf spring22formed in the metal cover3. Thus, static electricity accumulated in the metal cover3can be released to the ground electrode through the leaf spring22and the cam lever retaining member60. It is therefore not necessary to form a ground terminal in the metal cover3as in the conventional connector.

As described above, in this embodiment, because the terminal end portion60aof the cam lever retaining member60accomplishes the grounding of the metal cover3to the printed circuit board, if the number of variations of the connector housing standoff specification increases, this can be dealt with by simply changing the length of the terminal end portion60aof the cam lever retaining member60according to each of the stand-off specifications. The cam lever retaining member60is small and inexpensive compared with the metal cover3, so that the manufacturing cost of the card connector can be minimized when meeting the requirements of a variety of stand-off specifications.

FIG.10andFIG. 11show a card connector with a different stand-off specification from that of the previous embodiment. In FIG.10andFIG. 11, the lower housing2has a plurality of legs70, which increase the stand-off distance from the lower housing2to the printed circuit board. According to the increased stand-off distance, metal fixtures71for fixing the card connector1to the printed circuit board are set high.

If the stand-off specification varies among the connectors, the metal cover3used in the embodiment shown inFIG. 2toFIG. 9can be used commonly. That is, only by elongating the stand-off lengths of the terminal portions31of the contact terminals30and the stand-off length of the terminal end portion60aof the cam lever retaining member60, it is possible to connect the contact terminals and the ground terminal of the card connector to the printed circuit board.

Although, in the embodiment above, the heart cam50is provided on the eject member42side and a pivoting fulcrum53aof the cam lever53is set on the lower housing2side, the present invention is also applicable to an eject mechanism in which, as in the prior art shown inFIG. 12, the heart cam is provided on the connector housing side and the pivoting fulcrum53aof the cam lever53on the eject member42side.

While in the embodiment above the heart cam50, the cam lever53and the cam lever retaining member60are provided on the side surface of the connector, it is also possible in this invention to provide them on the top surface or bottom surface of the connector.

Further, it should be noted that the eject mechanism shown in the embodiment above represents only one example and other eject mechanisms of arbitrary constructions may be adopted. The present invention is also applicable to a construction in which the eject operation is initiated by an eject button.

Further, while in the embodiment above the Memory Stick (tradename) is used as the IC card10, this invention can also be applied to other kinds of card, such as SIM card, MMC and SD card.

The present invention may also employ any other shape and material for the connector housing.

As described above, since the cam lever of the eject mechanism is held from outside by the cam lever retaining member which in turn is held from outside by the leaf spring formed in the metal cover, the cam lever is doubly retained by the cam lever retaining member and the leaf spring. This arrangement can not only reliably prevent a possible dislocation of the cam lever but also enhance a clicking feel of the eject mechanism as the card is inserted or ejected.

Further, in this invention, because the metal cover of the card connector is grounded to the printed circuit board through the cam lever retaining member, the static electricity that has built up in the metal cover can be discharged to ground through the cam lever retaining member. Hence, if the number of variations of the connector housing stand-off specification increases, the construction described above allows the metal cover to be used commonly and only requires preparing the cam lever retaining members, which are small and inexpensive parts, according to a variety of the stand-off specifications. The manufacturing cost of the card connectors therefore can be minimized when dealing with a variety of stand-off specifications.