JP2000200638A - Connector having pre-loading contact and its using method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-cost connector to make good contact with a smart card. SOLUTION: This connector 1 has an insulating structure 2 and a number of elastic conductor strips 3-8 held in the insulating structure 2 and provided with soldering contact pins. Pre-load is applied to the soldering contact pins 11-13 and the insulating structure 2 has fixed members 14-17 aligned in a plane against which the pre-load contact pins 11-13 are pushed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connector having pre-loaded contacts and a method of use. Such a connector has an elastic conductor strip provided with soldering contact pins and an insulating structure supporting the elastic conductor strip. The invention has particular application in mounting connectors on printed circuits, and is specifically designed to ensure electrical connection between the microcircuits of smart cards and the microcircuits of electronic systems. Used for surface mount type connectors.

[0002] These electronic systems are, in a preferred embodiment, smart card reader or mobile telephone electronic systems. This type of connector has a resilient conductor strip designed to ensure electrical contact by pressure with a metal surface or contact area on the smart card. In addition, the contact between the connector's soldering contact pins and the surface on the printed circuit to which these pins are to be soldered must be planar. The present invention finds an advantage in improving the coplanarity between any soldering contact pins in electrical contact and the surface of the printed circuit.

[0003]

2. Description of the Prior Art Currently manufactured connectors designed for surface mounting include soldering contacts, one free end of which is curved to provide a plane of contact with the printed circuit. Has pins. Each solder contact pin has a local contact plane designed to contact the printed circuit. Considering the local contact planes of all contacts, it can be seen that the positions of the contacts of the connector vary in the thickness direction perpendicular to the plane of the printed circuit with respect to the plane of the circuit.

In practice, it is not easy to obtain the same planarity of the contact pins to be soldered (surface mounted) according to the step of bending the elastic conductor strip performed at the time of manufacturing the connector. That is, while there may be considerable differences in shape and / or dimensions between the two elastic conductor strips, the contact pins of the soldering strip are not perfectly flat. Furthermore, even though each is flat, the plurality of soldering contact pins may have different contact surfaces and / or non-parallel contact surfaces. Therefore, there has been a problem with this type of connector.

[0005] This type of connector generally comprises an insulating structure made of thermoplastic resin and a certain number, for example, six, of bronze contacts. These contacts are processed to form a triple coating of nickel, tin-lead, and a final layer of gold for contact with the smart card. The pins of these contacts are designed to be surface mounted on a printed circuit. Here, a connector of this type can provide a good electrical connection during the use of the product, during surface mounting of the connector, and throughout the life of the device in which it is mounted, sometimes under severe operating conditions. It must be designed to properly ensure sufficient contact pressure in order to conduct electrical conduction.

In practice, for example, smart card connectors belonging to mobile phones or any other electronic systems that are susceptible to vibration will transmit these vibrations to the smart card as well as to the connector. In this case, if the vibration is very strong, the contact pressure between the smart card and the connector is impeded or bad, leading to errors in reading or writing data on the smart card, thus reducing the contact pressure on the smart card. There is a problem with that.

[0007] Therefore, in order to determine that the contact with the smart card is sufficient, the supporting plane of the soldering contact of the connector is matched with the contact plane of the printed circuit, or at least pseudo-matched. It turned out to be necessary. In fact, this co-planarity effectively meets the so-called coplanarity (intrinsic flatness) requirements needed to perform a processing CMS for surface mounting. The request is that any contact,
This means that it must be located within a maximum allowable range, preferably a small value, with respect to the support plane of the contact pins of the connector to be soldered to the printed circuit. The support plane defines a reference plane for the coplanarity.

Further, the size of the connector is limited, so that the contact pins for soldering cannot be guided sufficiently accurately. All of this means that this support plane cannot be determined accurately and reproducibly, and therefore there is considerable variability in coplanarity.

More specifically, in order to ensure effective CMS soldering, the components, ie, the exits of the soldering contact pins, must be designed to ensure coplanarity of less than 0.1 mm. . This means that, in practice, the tolerance is 0.1 mm (X ±
0.05 mm), the support plane of the insulator of the part and the CM
It is described by a dimension X representing the distance between the S exit and the soldering surface.

This dimension X is due to the double curvature of the elastic conductor strip (the contact area with the smart card must be elastic), and most of the problems encountered are due to the Elastic. This elasticity varies depending on the material used to construct the elastic conductor strip, its thickness, or the surface treatment applied. To ensure mass production of elastic conductor strips with tolerances less than about 0.05 mm,
Too many influencing factors.

Furthermore, this problem raises another problem. In fact, each connector needs to be inspected on the assumption that the coplanarity of the printed circuit with the contact surface is likely to be defective. This inevitably results in an increase in the number of connectors to be discarded and an increase in the time required for individual inspection as the number of connectors increases, thereby increasing the time required, thereby increasing the overall number of connectors. This will increase costs.

[0012]

SUMMARY OF THE INVENTION The present invention provides a connector having an insulating structure and a number of elastic conductor strips held within the structure, each strip having a contact pin for soldering. To solve the above-mentioned problem. The insulating structure has fixed pieces arranged in one plane. Contact pins for soldering
Due to the effect of the applied preload, it is supported on the fixed piece in this plane. Therefore, it is understood that the contact surface of the soldering contact pin is arranged in the plane of the fixing piece with an accuracy of about 0.2 mm, provided that the insulator is formed with such accuracy. As a result, the contact between the soldering contact pins of the connector and the printed circuit surface is completely planar. Therefore, it is also understood that the contact area of the elastic strip with the smart card is in a plane completely parallel to the contact surface of the smart card.

Therefore, the present invention provides an insulating structure,
A connector having a large number of elastic conductor strips held in the insulating structure, wherein each elastic conductor strip is provided with a contact pin for soldering, and the contact pin for soldering is pre-loaded, The object is characterized in that it has fixing pieces arranged in a plane against which the pre-loaded contact pins are pressed.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS The invention can be better understood with reference to the following description with reference to the accompanying drawings, in which: FIG. The drawing is
It is attached as an example and does not limit the invention in any way.

FIG. 1 is a perspective view showing a connector according to the present invention. FIG. 2 is a perspective view showing an elastic conductor strip of the connector according to the present invention. FIG. 3 is a plan view showing a fixed plane of the elastic conductor strip having two lateral arms. FIG. 4 is a longitudinal sectional view of the connector according to the present invention.

FIG. 1 shows a connector 1 according to the present invention. The connector 1 has an insulating structure 2 and, in a preferred embodiment, six elastic conductor strips 3-8. They are symmetrically and regularly divided into three groups along two opposite sides 9, 10 of the insulating structure 2. In the following, the description will be limited to the members arranged on the side part 9, but the members of the side part 10 are easily understood from the symmetry with the members of the side part 9.

The elastic conductor strips 3, 4, 5 are provided with contact pins 11, 12, 13 for soldering, respectively. In a preferred embodiment, these soldering contact pins are plate-shaped and are arranged at the first ends of the strips 3, 4, 5. In addition, these solder contact pins 11, 12, 1
3 are arranged vertically on the side 9 of the insulating structure 2. Further, the insulating structure 2 has fixing pieces 14, 15, 16, 17 regularly arranged in one plane. This plane is perpendicular to the side 9.

Contact pins 11, 12, 1 for soldering
3 has a generally T-shaped widened portion. These T-shaped widened portions continuing from the soldering contact pins 11, 12, 13 correspond to the fixing pieces 14, 15, 16, 1 and 2, respectively.
7 is supported below. For this purpose, each soldering contact pin is arranged between two fixing pieces.

In a preferred embodiment, the fixing pieces 14 to
Reference numeral 17 denotes a structure which stands upright on the side part 9,
It has at least one flat surface. These flat surfaces support the contact pins for soldering thereunder. These fixing pieces are substantially rigid, so that the pressure exerted by the soldering contact pins is not sufficient to deform the support plane of the fixing pieces. Therefore, the widened portion of the soldering contact pin 11 is supported by the two fixing pieces 14, 15, and the soldering contact pin 12 is supported by the two fixing pieces 15, 16.
And so on. Fixing pieces 14-17
Is obtained within the required tolerance by design (molding).

FIG. 2 shows the elastic conductor strip 3 of the connector 1. The strip 3 has a fixing plate 18 at an intermediate position. This intermediate position is a position where the fixing plate portion 18 is closer to the end having the soldering contact pin than the other end of the elastic conductor strip 3. The fixing plate 18 is forcibly inserted into a housing 19 provided in the insulating structure 2. Insulation structure 2
Also has a housing for another elastic conductor strip. Therefore, in the illustrated example, the insulating structure 2 is
It has six housings 19 to 24. Fixed plate part 1
By the forced insertion of 8, the fixing plate portion 18 and the insulating structure 2 can be reliably fixed. In this fixed plate part 18,
Two lateral arms 25 and 26 projecting in the lateral direction are provided. The forced insertion of the fixing plate portion 18 into the housing 19 provided on the insulating structure 2 has an effect of inserting the two horizontal arms 25 and 26 into two horizontal grooves formed in each housing.

Once the strip has been inserted, the contact pins 11 are pre-loaded so as to be pressed against the fixing pieces 14,15. Therefore,
The opposed fixing pieces 14 and 15 maintain the elastic conductor strip 3 in a state of being permanently elastically deformed. By this preload, the contact pin 11 for soldering is fixed to the fixing piece 1.
4, 15 can be reliably contacted. In the connector of the present invention, the contact pin for soldering 1
Opposing the repulsive forces exerted by 1 to 13 are fixing pieces 14 to 17 on the side 9 of the insulating structure 2.

In a preferred embodiment, the insulating structure 2 is obtained by molding. Currently used molding processes can obtain flat surfaces and dimensions with an accuracy of about 0.02 mm (i.e., the undulation changes in a space where the thickness can be reduced to about 0.02 mm). Surface can be obtained.).

Thus, the elastic properties of the strip are used. In practice, when the soldering contact pin is supported by the fixing piece, the repulsive force is enough to deform the soldering contact pin, and therefore, the distance between the soldering contact pin and the fixing piece is increased. Contact is flat. Therefore, in the case of the present invention, the flatness obtained for the soldering contact pins 11 to 13 is larger than the flatness obtained in the related art.

FIG. 3 shows a fixed plate portion 18 provided with two horizontal arms 25 and 26. Two horizontal arms 2
5 and 26 are extended by two lateral mounting claws 27 and 28, respectively, in parallel with a plane passing through the fixing plate portion 18. The lateral mounting claws 27, 28 have a harpoon or wedge shape,
The first side portions 29 and 30 are connected to the side arms 25 and 26, respectively.
Are perpendicular to one ends 31 and 32, respectively. The second side portions 33 and 34 are inclined with respect to the end portions 31 and 32, respectively. The mounting claws 27 and 28 are
Are inclined with respect to the insertion direction of the fixing plate portion 18 so as to enter the grooves 35, 36 provided in the walls 37, 38 of the mounting plate 27, 28 from the inclined side portions 33, 34 of the mounting claws 27, 28.
The sides 29, 30 of the mounting claws 27, 28 enter the second position.

At the start of the insertion of the lateral arms 25, 26 into the grooves 35, 36, the mounting claws 27, 28 will bite into the walls 40, 41 of the grooves 35, 36 facing each other. . Therefore, the two mounting claws 27, 28
Deforms the walls 40, 41 under the action of the insertion force applied to the fixing plate 18. The deformation of the walls 40, 41 is caused by the mounting claws 27, 28,
8 has an effect of generating a compressive stress. At the end of the insertion, the fixing plate portion 18 comes into contact with the walls 42 and 43 constituting the end portions of the grooves 35 and 36, respectively. In this state, the fixed plate portion 18 cannot move further by the walls 42 and 43, nor can it move in the lateral direction due to the compressive stress applied by the walls 40 and 41. The vertical movement of the mounting claws 27, 28 against any rearward movement of the part 18 also prevents the rearward movement.

Therefore, the fixing plate 18 is fixed and does not have any degree of freedom. Further, the two front corners 44 and 45 of the fixing plate 18 are chamfered. These two
Corners 44 and 45 are provided at the ends 3 of the lateral arms 25 and 26.
1 and 32 and side portions 46 and 47, respectively. These side portions 46 and 47 come into contact with the walls 42 and 43 of the grooves 35 and 36 at the end of the insertion of the fixing plate portion 18, respectively. These chamfered corners 44, 4
5 can assist the engagement of the fixing plate portion 18 into the grooves 35 and 36, respectively.

FIG. 4 shows a cross section of the connector 1 cut along a cut surface passing through the elastic conductor strips 3 and 8 (the elastic conductor strip 8 is not shown). In a preferred embodiment, the housing 19 for receiving the conductor strip 3 has a first opening on the side 9 of the insulating structure 2 and is perpendicular to the side 9 and parallel to the contact surface of the fixing piece. The side portion 48 has a second opening.

Therefore, the elastic conductor strip 3 introduced into the side part 9 is compressed in the housing 19. For this purpose, the elastic conductor strip 3 has a folded form, and is disposed in a plane parallel to a plane passing through the fixing plate portion 18 and not merging with the plane.
End 49. A portion of the elastic conductor strip 3 disposed between the end portion 49 and the fixing plate portion 18 is such that a part of the portion protrudes from the second opening of the side portion 48 at the saddle-shaped portion 50. It is curved. This curved portion of the elastic conductor strip 3 is designed to make an electrical contact between the smart card and the connector 1. The contact area of the saddle-shaped part 50 with the smart card can move with respect to the fixed plate part.

Thus, due to this curved configuration of this part of the elastic conductor strip 3, when pressure is applied, a spring effect of a part of this part along an axis perpendicular to the side 48 is obtained. Can be. This spring effect ensures, in a preferred embodiment, the electrical contact by pressure between the elastic conductor strip 3 and the metal contact area of the smart card.

Further, the end 49 of the elastic conductor strip 3
Is subjected to a second preload. To this end 49
Is fixed between the walls 37 and 38 of the housing 19 by means of the fixing piece and the fixing piece 51 formed on the wall 38 and the fixing plate portion 1.
The distance between the plane and the plane passing through 8 is kept smaller than the distance between this same plane and the end 49 when no stress is applied. Therefore, the end 49
Can move only in a single direction on the opposite side of the fixed piece 51 in the housing 52. The T-shaped wide portion of the end portion 49 of the elastic conductor strip 3 is
Support can be given.

This second preload is intended, in particular, to ensure a substantially identical contact surface for all contact areas, which contact surface is parallel to the contact surface of the solder contact pin. . The distance between the top 53 and the side 48 of the saddle is such that even if the saddle 50 is forced into the housing 19 by the pressure exerted by the connected smart card, at least the top 53 is outside the housing 19. It is a distance that will remain. The resulting repulsion thus ensures a sufficient pressing pressure of the contact area of the connector 1 against the contact area of the smart card such that electrical contact is obtained by the pressure according to the above-mentioned criteria.

During insertion of the elastic conductor strip 3 into the housing 9 of the insulating structure 2, it is necessary to elastically bend the end 49 toward the fixing plate 18. Thereby, the end 4
9 can be inserted into the housing 52. After releasing the bending force, the end 49 comes into contact with the fixing piece 51. Furthermore, during insertion, the contact pins 11 of the elastic conductor strip 3 are arranged at predetermined locations. In this case, the elastic conductor strip 3 is
8, two repulsive preloads are applied.

The first preload is a preload of the soldering contact pins 11 to 13 with respect to the fixing pieces 14 to 17. In the example, two fixing pieces are used to create a preload on one soldering contact pin. Therefore, each contact pin for soldering is arranged between two fixing pieces. As a result of placing the soldering contact pins between the fixing pieces, the strip no longer moves. Therefore, the risk of catching the mounting strip during the installation operation is limited.

The insulating structure 2 is, in a preferred embodiment,
It is formed by molding an insulating thermoplastic resin material. Such materials are resilient and mainly utilize deformation during insertion of the securing means for the elastic conductor strip as described above. The elastic conductor strips 3 to 8 are made of bronze in a preferred embodiment, and bronze is a material having elasticity and ease of molding. That is,
The elastic conductor strip can be easily deformed. This is one of the requirements when the contact strip is to be supported on a fixed piece of insulating structure. Therefore, the contact strip conforms to the undulating shape formed by the fixing piece. Furthermore, the saddle-shaped structure of the elastic conductor strip, which ensures the contact with the smart card, improves the contact characteristics of the elastic conductor strip, and thus helps a good electrical contact between the connector 1 and the smart card. Nickel, tin-
Coated with lead alloy and / or gold.

Generally, the contact pin at the CMS outlet is
It should be noted that it is easily deformable, so that the fixing piece can also reliably protect the pin during any operation.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a connector according to the present invention.

FIG. 2 is a perspective view showing an elastic conductor strip of the connector according to the present invention.

FIG. 3 is a plan view showing a fixing plane of an elastic conductor strip having two lateral arms.

FIG. 4 is a longitudinal sectional view of the connector according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Connector 2 Insulating structure 3,4,5,6,7,8 Elastic conductor strip 11,12,13 Contact pin for soldering 14,15,16,17 Fixing piece 18 Fixing plate part 19-24 Housing 27,28 Side mounting claws 44, 45 Side corners 49 Second end

Claims (10)

[Claims] 1. An insulating structure (2) and a plurality of elastic conductor strips (3, 3) held in the insulating structure (2).
4,5,6,7,8), wherein the elastic conductive strip is provided with soldering contact pins, wherein the soldering contact pins (11,12,13) are provided. And the insulating structure (2) is provided with the pre-loaded contact pins (11, 12, 13).
The fixing pieces (14, 1) aligned on the plane on which
5,16,17). 2. The connector according to claim 1, wherein said soldering contact pins are in the form of a flat plate disposed at a first end of said strip. 3. The connector according to claim 2, wherein the soldering contact pin supported by the fixing piece has a T-shaped widened portion. 4. The connector according to claim 1, wherein said elastic conductor strip is provided with a fixing plate portion (18) arranged at an intermediate portion of said insulating structure (2). 5. The fixed plate portion has side mounting claws (27, 28) for the insulating structure, and two side corners (44, 45) of the fixed plate portion are chamfered. The connector according to claim 4, wherein the connector is provided. 6. A housing for the insulating structure, wherein the elastic conductor strip has a curved shape.
The connector of claim 1, wherein the second end (49) of the resilient conductor strip is subjected to a second preload within the housing of the insulating structure. 7. The housing according to claim 6, wherein the elastic conductor strip has a width equal to a passage groove of the housing, and a T-shaped second end is supported at an edge of the passage groove. The connector described. 8. The elastic conductor strip is made of bronze, the contact area is coated with nickel, a tin-lead alloy and gold, and the insulating structure is made of a thermoplastic insulating material. The connector according to claim 1. 9. The method of using a connector according to claim 1, wherein the connector is surface-mounted on a printed circuit by the soldering contact pin. 10. A printed circuit, wherein the connector according to claim 1 is surface-mounted by the contact pins for soldering.