Memory card connector having switch terminal equipped with improved contact

The present invention generally relates to the technical field of electrical connectors, and more particularly to memory card connectors having switch terminals with improved engagement between contacts.

Memory cards are known in the art and contain information in the form of memory circuits or other electronic programs. Some form of card reader reads the information or memory stored on the card. Such cards are used in today's electronic society for camcorders, digital still cameras, smartphones, PDAs, music players, ATMs, cable TV decoders, toys, game consoles, PC adapters, multimedia cards, and , Used in many applications such as other electronic applications. Generally, a memory card includes a card reading system via a card connector, and then an array of contacts or terminals for connecting to an external device. The connector easily accommodates card insertion and removal, which is done for quick access to information and programs on the card. The card connector includes terminals that flexibly engage the contact array of the memory card.

Memory card connectors are often mounted on printed circuit boards. The memory card itself can write and read through this connector, and can also transmit between electronic devices such as a word processor, a personal computer, and a personal digital assistant.

Some memory card connectors have a write-protect function with a pair of elastically conductive terminals that make up the control switch. The two switch terminals are attached to the sides of the connector and have their respective elastic arms arranged in close proximity to each other, driven by a memory card to engage with each other and close the control switch. Also, some memory card connectors have a detection function that is achieved when the third switch terminal is moved by the memory card (such as the front edge of the memory card) and engages with one of the other switch terminals. is there. This indicates or detects that the card is fully inserted into the connector.

<p> The memory card connectors of the types described above have problems in maintaining a good positive engagement between the contacts of the switch terminals. Since the contacts are generally planar as a whole, good and positive contact engagement is established only when the opposing planes of the contacts are completely engaged with each other. Unfortunately, the switch terminals are easily twisted and deformed, which reduces the contact area between the contact parts and increases the resistivity. In other words, the smaller the actual contact area of the opposing contacts reduces the conductivity between the two switch terminals. The present invention solves these problems.</p>

<p> Therefore, an object of the present invention is to provide a memory card connector having an improved switch terminal.</p><p> In an exemplary embodiment of the invention, the memory card connector comprises a rear terminal attachment and at least one side wall extending forward from one end of the rear terminal attachment, with a card storage space between them. It has an insulating housing that defines it. A first conductive terminal is attached to the housing and has a first contact with a first protrusion. A second conductive terminal is attached to the housing and has a second contact with a second protrusion. The contact portions of these terminals are usually arranged apart from each other but close to each other, and the contact portions and the protrusions engage with each other when the memory card is inserted into the card storage space. Since the protrusions are offset from each other, the first protrusion of the first terminal engages with the second contact of the second terminal, and the second protrusion of the second terminal is the first of the first terminal. Engage with the contact part of.</p><p> According to one embodiment of the invention, the first and second terminals are attached to one side wall of the housing. The contact portion of the terminal is flat as a whole. The protrusions on the terminals are convex to provide rounded contacts directed at the contacts of the other terminal.</p><p> As described herein, the terminals are punched out of a sheet metal material and the protrusions are convexly punched out of the contact portions of the terminals. Each terminal is provided with a main body portion fixed to a housing, a contact spring arm is cantilevered from the main body portion, and the contact portion of the terminal is formed at the free end of the contact spring arm.</p><p> According to another embodiment of the invention, a third conductive terminal is attached to the housing. The third terminal has a third contact with a protrusion. The second conductive terminal has a pair of second contact portions and a corresponding pair of second protrusions. The second terminal is a common terminal, and the pair of the second contact portion and the second protrusion is the first contact portion of the first terminal and the third contact between the first protrusion and the third terminal, respectively. Operatively associated with the part and the third protrusion.</p><p> Other objects, features and advantages of the present invention will become apparent from the following detailed description made in connection with the accompanying drawings.</p><p> Features of the invention that are considered novel are described in detail within the appended claims. The present invention, along with its purpose and advantages, will be best understood by reference to the following description made in connection with the accompanying drawings. Throughout all drawings, the same reference numerals indicate the same elements.</p>

The description will be given with reference to the drawings in detail. First referring to FIG. 1, the present invention is practiced within the memory card connector shown by 10. The memory card connector 10 has an insulating housing as a whole indicated by 12, and the housing as a whole has a U shape. The housing includes a rear terminal mounting portion 14 and at least one side wall portion 16 extending forward from one end of the rear terminal mounting portion. In the case of the U-shape, the second side wall portion 18 extends forward from the other end of the rear terminal mounting portion. However, there is also an overall L-shaped memory card connector in which one side wall 16 projects forward from the rear.

A plurality of connector terminals, indicated by 20 in their entirety, are attached to the rear portion 14 of the housing. This connector is adapted to be mounted on a printed circuit board, and the terminal 20 has a tail portion 20a for connecting to an appropriate circuit trace on the printed circuit board, such as by soldering. The terminal has a contact portion 20b projecting forward from the rear portion 14 within the card storage space 20 defined between the front side wall portions 16 and 18 of the rear portion 14. A memory card (not shown) is inserted into the card storage space in the direction of arrow A. The memory card has an array of terminals that engage the contact portion 20b of the terminal 20.

As described in the above-mentioned "background technique", some memory card connectors have a write-protect function using a pair of switch terminals. Similarly, some have a card detection function using a pair of switch terminals. The connector 10 includes a plurality of switch terminals, which effectively perform both a write-protect function and a card detection function.

Specifically, referring to FIG. 2 together with FIG. 1, the first switch terminal shown by 24 and the second switch terminal shown by 26 are the third switch terminal shown by 28, that is, the whole is shown by 28. Operatively associated with "common" switch terminals. The first switch terminal 24 has a contact spring arm 24a, and the distal end of the arm is formed with a flat, i.e., flat, contact portion 24b, which is rounded, i.e. , The convex protrusion 24c protrudes from the contact portion. The second switch terminal 26 has a contact spring arm 26a, at the distal end of the arm a flat, or generally planar, contact portion 26b, which is rounded, i.e. convex. The protrusion 26c of the above protrudes from the contact portion. As can be seen from the following description, the first switch terminal 24 activates the write protection function of the connector, and the second switch terminal 26 activates the card detection function of the connector.

The third, i.e., common switch terminal 28, is operably associated with both the first switch terminal 24 and the second switch terminal 26. The first and second switch terminals 24 and 26 are provided with a main body portion 24d and a main body portion 26d for fixing the terminals to the side wall portion 16 of the housing 12, respectively, and are suitable circuits on the printed circuit board by soldering or the like. And equipped with legs 24e and 26e for connecting with the race.

The third, i.e., common switch terminal 28, has a body 28a fixed to the side wall 16 of the housing 12. A pair of contact spring arms 28b and 28c are cantilevered and supported in the same direction from the main body. Overall flat, i.e., planar contact portions 28d and 28e are formed at the free ends of the contact spring arms 28b and 28c, respectively, as magnifying contact pads. Projections 28f and 28g are formed on the contact portions 28d and 28e. As shown in FIG. 2, the protrusion faces the contact portion of the first switch terminal 24 and the second switch terminal 26.

All switch terminals 24, 26 and 28 can be punched from conductive sheet metal material. The protrusions 24c, 26c, 28f and 28g are formed by embossing the planar contact portions 24b, 26b, 28d and 28e of each terminal, respectively. Thus, the protrusions can be made convex to provide a rounded contact that is directed towards the contacts of the other corresponding terminals.

FIG. 3 shows switch terminals 24, 26 and 28 mounted in the appropriate slots on the side wall 16 of the housing 12, and FIGS. 3A and 3B show the contact area between the terminals. Specifically, FIG. 3A shows a state in which the contact portion 24b of the first switch terminal 24 is usually separated from the contact portion 28b of the common switch terminal 28 but is close to each other. The protrusions 24c and 28f of each terminal are also usually separated. Similarly, FIG. 3B shows a state in which the contact portion 26b of the second switch terminal 26 is normally separated but close to the contact portion 28e of the common switch terminal 28. The protrusions 26c and 28g are also separated.

Referring to FIG. 4 together with FIGS. 3A and 3B, in the present invention, the protrusions are staggered from each other in each connection interface between the terminals, and the protrusions do not engage with each other, but rather one terminal. The protrusion can be made to engage the contact portion of the other terminal. In other words, in FIG. 4, since the protrusion 24c of the first switch terminal 24 is deviated from the protrusion 28f of the common terminal 28, the protrusion 24c of the first terminal engages with the contact portion 28b of the common terminal and is a common terminal. The protrusion 28f of the first terminal 24 engages with the contact portion 24b of the first terminal 24. Similarly, in FIG. 3B, the protrusion 26c of the second switch terminal 26 engages with the contact portion 28e of the common terminal 28, and the protrusion 28g of the common terminal engages with the contact portion 26b of the second terminal.

When the memory card is inserted into the card storage space 22 in the direction of the arrow "A" (FIG. 1), the side edge of the card engages the contact portion 24b of the first switch terminal 24 (FIG. 3A) and then. , Engage with the contact portion 26b of the second switch terminal 26 (Fig. 3B). As a result, the contact spring arm 24a of the first switch terminal and the contact spring arm 26a of the second switch terminal are sequentially urged outward toward the common switch terminal 28. Then, as described in detail above in connection with FIG. 4, the protrusions of the first and second switch terminals and the protrusions of the common terminal are engaged with each other. By moving the memory card, the first switch terminal 24 engages with the third switch terminal 28 to effectively operate the write protection function of the connector, and then when the memory card reaches the full insertion position, the second switch terminal The switch terminal 26 engages with the third switch terminal 28, and the card detection function of the connector operates effectively.

Various advantages can be obtained by connecting and engaging the terminals as described above. First, the protrusions form very positive contacts between the terminals. The misaligned protrusions provide extra contacts to ensure good positive contact engagement between the terminals. It was found that this engagement reduces the resistance between the terminals and greatly improves the conductivity between the terminals. That is, this memory card connector has electrical reliability not found in the prior art.

FIG. 4A shows that there are many engaging micropoints 32 between the terminal protrusions and the terminal contacts. This reduces the electrical resistance between the terminals.

Finally, FIG. 5 is a graph showing the resistance characteristics with respect to the contact area between the switch terminals of the memory card connector, where the Y coordinate shows the resistance and the X coordinate shows the contact area. It can be seen that the larger the contact area, the lower the resistance and the higher the conductivity. FIG. 5 further shows three sets of fine contact points 32, emphasizing that the larger the number of contact points, the larger the contact area, the lower the resistance and the higher the conductivity.

It will be found that the present invention can be practiced in other particular embodiments without departing from its spiritual or core features. Therefore, the examples and embodiments must be considered to be exemplary and not limiting in all respects, and the invention is not limited to the details presented herein.

<figref num="1">It is a perspective view of the memory card connector according to this invention, and shows the state in which a switch terminal is lifted from a housing.</figref><figref num="2">It is an enlarged perspective view of the area surrounded by "A" of FIG.</figref><figref num="3">It is a perspective view seen from the top of the connector in an assembled state.</figref><figref num="3A">It is an enlarged fracture perspective view of the region surrounded by "A" of FIG.</figref><figref num="3B">It is an enlarged fracture perspective view of the region surrounded by "B" in FIG.</figref><figref num="4">The figure is similar to FIG. 3A, but shows a state in which the terminals are engaged with each other.</figref><figref num="4A">It is an enlarged view of the contact point in "A" of FIG.</figref><figref num="5">It is a graph which shows the resistance characteristic with respect to the contact area between terminals of this invention.</figref>