A SELF-SUPPORTING CONTACT ELEMENT, IN PARTICULAR FOR A SMART CARD CONNECTOR, AN A SMART CARD CONNECTOR USING THE SAME

Abstract: A contact element having a frame defining a frame defining an opening therein, wherein within said opening the contact element defines a contact element arm, which projects out of a plane defined by said frame.

Description: A self-supporting contact element, in particular for a smart card connector, and a smart card connector using the same. The present invention relates to a contact element. The contact element to which the invention relates is particularly suitable for use in a smart card connector for contacting a contact zone of a smart card. The contact element of the invention can also be used for contacting other elastical devices like batteries and microphones located within respective apparatus. Smart card connectors are widely used, for example in the business world. Smart card connectors and in particular SIM card connectors (a smart card connector for a SIM card) are used in a variety of apparatus. The apparatus, for instance a cell phone hand set, allows little space for the smart card or SIM card connector because of the desire to keep the apparatus as small as possible. There exists, for instance, with cell phones a continuous tendency to miniaturize the cell phones. This tendency requires that the smart card connectors and SIM card connectors, respectively, are as small as possible and have, in particular, a small height. Known smart card connectors use contact elements which are mounted in a body or a frame of the smart card or SIM card connector in two ways. Inasmuch as the body consists typically of a plastic material, the contact elements can be fixedly mounted within the body at the time the plastic body is injection molded. The other typical approach for mounting the contact elements in the body or frame is to provide cavities in the body into which the contact elements are inserted and are typically locked therein by detent means. Due to the manufacturing requirements the entire thickness of the body of the smart card connector and thus of the smart card connector itself is quite substantial. Summary of the invention The present invention relates to a contact element adapted to provide an electrical contact between two separate contact zones, preferably the contact zone of a smart card and the contact zone of a printed circuit board or a contact zone provided on an apparatus together with which a smart card is to be used. The contact element comprises a self-supporting metal frame together with a unitary contact element arm. The contact element comprises a frame and the contact element arm, preferably stamped out of a piece of sheet metal. The frame defines a plane with the contact element arm being bent out of said plane such that a free end of the contact element arm ends in a plane different from the plane defined by the frame. The free end of the contact element arm is preferably cusp-shaped, i.e. forms a rounded portion adapted to contact a contact zone of a smart card called a cusp portion. The cusp portion or rounded section provided at the free end of the contact element arm has a certain radius and is formed by embossing. The frame is preferably rectangular and at opposite ends of the frame termination sections are provided, preferably unitary with the frame itself. These termination sections are formed by bending extensions unitary with the frame into preferably one plane located in a direction opposite to the plane to which the free end of the contact arm extends, i.e. a plane which is spaced from the plane defined by the frame. Brief description of the drawings The foregoing and other features of the present invention become apparent to one skilled in the art to which the present invention relates upon consideration of the following description of the invention with reference to the accompanying drawings, in which: Fig.1 is a perspective top plan view of three contact elements of the invention; Fig. 2 is a side elevational view in the direction of arrow A in Fig. 3 of a part of a smart card connector of a first design of the invention using the contact elements of Fig. 1 ; Fig. 3 is a top plan view of a part of the smart card connector of Fig. 2 comprising the contact elements shown in Fig. 1. Fig. 1 discloses three identical self-supporting contact elements 10. For contacting the contact zones of a smart card (not shown) typically six or more contact elements 10 are necessary. Fig. 1 does not show how the smart card connector referred to by reference numeral 1 is realized, i.e. where in Fig. 1 the contact elements 10 are mounted. There are two preferred smart card connector designs, using the contact elements 10 of the invention. The first design is shown in Figs. 2 and 3, where the smart card connector 1 comprises a printed circuit board 9 and the desired number of contact elements 10 is being soldered with their mounting arms or termination sections 17, 29 (Fig. 1) (yet to be described) to contact zones or conductive paths provided by said board 9. Typically at least six contact elements 10 are used, e.g. arranged in two rows. A second design of a smart card connector 10, not shown but suggested by the representation of Fig. 1 , is as follows: Not only one row of contact elements 10, as shown in Fig. 1 , but preferably two rows of contact elements 10 are arranged next to each other such that contact element arms 12 (yet to be described) of the contact elements 10 can contact the contact zones of a smart card which is inserted into an apparatus in which the contact elements 10 are mounted. According to the second design of a smart card connector, the contact elements 10 of the type shown in Fig. 1 are directly mounted on a respective component or components of said apparatus, which is, for instance, a hand set used in a mobile phone system. Like in the first design, the termination sections 17, 29 (yet to be described) of the contact elements 10 could be soldered or in other wise connected to contact zones or conductive paths provided on said component or components of said apparatus. The contact element 10: The contact element 10 comprises a self-supporting frame 11 and the contact element arm 12 supported by said frame 11. Preferably, frame 11 and contact element arm 12 are formed from a single piece of sheet metal. The frame 11 of the contact element 10 comprises two oppositely located elongate longitudinal arms 15 and 16, which are connected to each other by means of two oppositely located arms, a transversal arm 17 (also called a termination section of the contact element) and a transversal arm 18. Different from what is shown and described, it is conceivable that the frame 11 is not continuously closed but open. For instance one of the transversal arms 17, 18 could be deleted. The transversal arm 17 The transversal arm 17 (also called termination section or soldering leg) supports the contact element arm 12, which projects in the direction towards the transversal arm 18 and ends in a free end. The contact element arm 12 extends from an area of the transversal arm 17 which is bordered or limited by recesses 19, 20. With respect to a plane defined by the arms 15, 16, 17 and 18, the contact element arm 12 projects upwardly (Fig. 1) under an angle α with respect to said plane. The transversal arm 17 defines at its lower surface a support or mounting surface 21 by means of which the frame 11 can be placed and mounted to the printed circuit board 9 as shown in Figs. 2. and 3. The support surface 21 is preferably soldered to a contacting path or a contacting zone provided on the printed circuit board 9. In the second smart card connector design referred to above, the support surface 21 could be e.g. soldered to a contacting zone on a component of the apparatus within which a smart card connector is to be provided. As is shown in Fig. 2 in some detail, the transversal arm 17 forms a flat plate- shaped support section 22. The contact element 10 comprises integrally formed with the support section 22 of the transversal arm 17 a bent or angled first section 23 leading to the longitudinal arm 15, a bent or angled second section 23 leading to the longitudinal arm 16 and a bent or angled central section 23 leading to the contact element arm 12. The first and second angled sections 23 continue in the form of a planar rib section 24 (see Fig. 2) of the contact element 10. Said planar rib section 24 comprising, in turn, the two substantially flat and planar longitudinal arms 15 and 16. Fig. 2 discloses further that the so-called rib section 24 forms at its right end said transversal arm 18 extending in the plane defined by the rib section 24. The longitudinally extending arms 15 and 16 are connected to said transversal arm 18 via angled sections, one of which is shown in Fig. 1 at 28. Moreover, an angled section 25 projects outwardly and downwardly preferably from the middle of the transversal arm 18. Said angled section 25 continues in a plate-shaped abutment section 26, as is shown for instance in Fig. 2. The angled section 25 forms together with the abutment section 26 a longitudinally extending termination section also called a mounting arm 29 or soldering leg. The mounting arm 29 is adapted to be placed with a support or mounting surface 30 on the upper surface of the printed circuit board 9, more specifically on a contact zone or contact path provided at an upper surface 91 of the printed circuit board 9. The mounting arm 29 can then be soldered to said contacting zone. As mentioned before, if in the second design no circuit board is used, then said contacting zone is provided on the apparatus or some component of the apparatus within which the smart card reader is going to be used. The mounting surface 30 is preferably located in the same plane as the support or mounting surface 21. The longitudinal arm 15 as well as the longitudinal arm 16 comprise bottom surfaces 31 (Fig. 2) which are located together with a bottom surface 32 of the transversal arm 18 in the same plane. The longitudinal arm 15 and the longitudinal arm 16 and the transversal arm 18 form upper surfaces 33, 34 and 35, respectively (see Fig. 3), which are all located in the same plane. The upper surfaces 33, 34, 35 of each of the required number (e.g. six) of contact elements 10 which are preferably in the same plane form a support surface for a smart card (not shown) which would face with its contact zones downwardly towards the contact element arms 12. The abutment or support surfaces 21 , 30 preferably have different widths so as to form a three-point support avoiding any tilting movements. The abutment surfaces 21 and 30 are provided on both opposite sides of the contact element 10 and extend longitudinally in opposite directions from the frame 11. As is shown in Fig. 2, but also in Fig. 1 , the bottom surfaces 31 , 32 are spaced from an upper surface 91 of the printed circuit board due to the presence of the angled sections 23 as well as the angled section 25. This spacing or distance is preferably selected, if present at all, to be relatively small so as to add only little to the design height of the smart card connector 1 defined by the contact elements 10. The contact element arm 12 The generally rectangular frame 11 defines a generally rectangular opening 40 into which the contact element arm 12 projects extending away from the transversal arm 17. The contact element arm 12 comprises a longitudinally extending resiliently hinged contact arm 121 (see Fig. 1) which extends by means of a planar plate section 123, yet to be described in detail, from the transversal arm 17 and is integral therewith. The entire contact element 10 is stamped out of a sheet of metal. After stamping, the stamped out contact element is bent or formed into the shape as shown in Figs. 1 , 2 and 3. Opposite to its free end, the contact arm 12 comprises the central angled section 23, referred to in Fig. 1 as angled section 122. Referring to Fig. 1 , contact arm 12 comprises the planar plate section 123 which is located on the same level as the longitudinal arms 15, 16. Thus in Fig. 2 the planar plate section 123 cannot be seen. The contact arm 12 comprises adjacent to the plate section 123 an angled section 126 and then adjacent to the angled section 126 an upwardly extending plate section 124. The plate section 124 ends at the free end of the contact element arm 12 in a curved section also called a "radius", as is shown for instance in Fig. 2. The radius is formed by embossing and forms contact sections in the form of a contact cusp 127 having a slightly downwardly extending section 128. The contact cusp 127 provides for the contacting effect of the contacting element 10 with a contact zone of a smart card. Thus, Figs. 1 and 2 show that the contact arm 121 is upwardly inclined by angle with respect to a plane defined by the upper surfaces 33, 34, 35. The angle α is relatively small, α is in the area of 8-25 degrees. Preferably is 12 to 18 degrees. The transversal arm 18 forms, like the transversal arm 17, a contact or termination section for the contact element 12. The contact or termination section 29 is preferably formed at the transversal arm 18. Depending on the design of the circuit board 9 both contact or termination sections 17 and 29, or else just one termination section, for instance termination section 29 could be soldered to the circuit board 9 and thus fixedly mounted thereto. In case that one of the termination sections 17, 29 is not soldered to the printed circuit board 9, then this termination section could be mounted in a different manner to the upper surface 91 of the printed circuit board 9, for instance by gluing. In the smart card connector embodiment as shown in Figs. 1 and 2, the smart card connector 1 comprises three contact elements 10 and thus three contact arms 12. Depending on the number of the contact zones of a smart card to be contacted, additional three or also more contact elements could be provided and be fixedly mounted on the printed circuit board 9. Industrial applicability For both designs of a smart card connector, i.e. the one shown in Figs. 2 and 3 as well as for the one where a contact elements as shown in Fig. 1 are mounted directly on contact zones of an apparatus within which a smart card connector needs to be provided, a smart card is placed on the contact cusps 127 which are preferably located in a single plane. The smart card is then pressed towards the upper surfaces 33, 34, 35 and also towards the upper surface of the planar plate section 123, such that the contact cusps 127 resiliently contact the respective contact zones of the smart card. When pressing the smart card in said direction, the contact arms 12 are resiliently pivoted into said openings 40 such that the angle α is more or less reduced to zero degree. With the contact elements of the invention, a safe and steady contacting effect is provided between the contact zones of a smart card and the contact elements 10. Moreover, the contact elements 10 of the invention allow for the design of a smart card connector which has an extremely flat design, i.e. a very small design height. This is achieved in a very simple manner. The present invention provides a contact element, in particular for use in contacting a contacting zone of a smart card, such that a smart card connector can be realized with the least possible design height. The invention further provides a smart card connector having small design height and using the contact elements of the invention. The contact element according to the invention is adapted to provide a contact or a contacting connection between a contact zone of a smart card and another contacting zone which is provided for instance by a printed circuit board or by an apparatus (i.e. by an apparatus using a smart card) itself. This contact or contacting connection is provided without actually requiring the above- mentioned frame or body made of plastic material of a smart card connector. Even though the contact element of the invention is preferably used to provide a contact between the contact zones of a smart card and the contact zones provided on a circuit board which, in turn, is used in an apparatus of for instance a cell phone hand set, the contact element of the invention can also be used to provide contact between contact zones of a smart card and a contact zone provided by a circuit board, but by some component of the apparatus. Due to this design it is basically possible that the entire design height of a smart card reader formed by a plurality of adjacent contact elements of the invention is equal to the thickness of the circular section of the cusp plus the thickness of the sheet metal forming the frame. Frequently, for prior art smart card connectors the printed circuit board used therewith requires bores so as to receive certain parts of a contact element, at the time the contact element makes contact with the contact zone of a smart card. Such bores are largely unnecessary due to the special form of the contact element of the invention. As was mentioned, the frame together with the contact arm and the termination sections are stamped out of a band of sheet metal. The form of the frame which is preferably rectangular provides the contact element with the necessary stability and also guarantees that the center of gravity and the contact point, i.e. the point for the contacting force, occurs is located within the geometry of the contact element, i.e. within the frame which is preferably of a closed rectangular design. The contact element is preferably fixedly mounted to a circuit board by means of soldering as is disclosed in the embodiment described in the specification. It is, however, also possible to fixedly mount the contact element at the printed circuit board by pressing. Modified termination sections would have to be used for that kind of fixing. The contact elements can be adapted to realize different design heights for the smart card reader using said contact elements by bending or angling the termination ends with different amounts. The geometry of the contact element makes it possible that the contact element can be soldered at both ends to e.g. a printed circuit board and thus, the so-called "tombstone" effect cannot occur during soldering. The tombstone effect is a situation where during soldering of only one end the other end tends to move up and reach the position of an upright tombstone. Thus, the contact element comprises a first termination section 17 adapted for being fixedly connected to and for contacting a contact zone on a printed circuit board or another component. The contact section 12, 7 is adapted to resiliently contact a contact zone of a smart card. The substantially rectangular frame 11 has first and second elongate arms 15, 16 which are connected by first and second transversal arms 17, 18, which define an elongate opening 40 therebetween. Said first transversal arm defines said first termination section. The elongate contact element arm 12 has a first end and a second end, with said first end being hingedly connected to said first transversal arm. The contact element arm 12 projects from the first transversal arm 17 into the direction of the elongate opening 40 and ends in a free end which is located closer to the transversal arm 18 than the transversal arm 17. The free end forms a termination end. The contact element arm (12) is movable between an unactuated position where no electrical connection is provided and an actuated position in which an electrical connection is provided. The contact element arm is bent upwardly with respect to a plane defined by the upper surfaces of the first and second elongate arms such that the free end forming the contact section is spaced from said plane in the unactuated position.

Claims: Claims 1. A contact element having a frame (11) defining an opening (40) therein, wherein within said opening the contact element defines a contact element arm, which projects out of a plane defined by said frame. 2. Contact element of claim 1 , wherein the frame (11) and the contact element (12) are formed as a single piece of sheet metal. 3. Contact element of claim 2, wherein the frame (11) and the contact element (12) are stamped out of sheet metal. 4. Contact element of claim 1 , wherein a single contact element arm (12) is provided at the frame (2). Contact element of claim 1 , wherein the frame (11) is rectangular. 6. Contact element of claim 1 , wherein the contact element arm (12) comprises a longitudinally extending contact arm (121), said contact element arm (121) being hinged at the frame (11 ) and extends preferably in the longitudinal direction of said opening. 7. Contact element of claim 6, wherein the contact arm (121) is connected with said frame (11) by means of a planar plate section (123). 8. Contact element of claim ?, wherein the contact element arm extends in a longitudinal direction of the opening (40) along a length of about four fifths of the length of the opening. 9. Contact element of claim 1 , wherein the contact arm comprises at the free end of the contact arm a cusp or contact section (127) at which a contacting force is applied, said point of application of said force being in an area within support surfaces formed by said contact element. 10. Contact element of claim 1 , wherein the frame forms at longitudinally opposite ends termination sections (17, 29) for supporting the frame on a printed circuit board or another component of an apparatus. 11. Contact element of claim 1 comprising two oppositely located termination sections (17, 29), which are provided with respective support surfaces (21 , 30) at which said contact element (10) can be soldered to a printed circuit board or another component. 12. Contact element of claim 11 , wherein the termination sections (17, 21) are located in the same plane, which is offset from a plane defined by longitudinal arms (15, 16), transversal arm (18), and a planar plate section of the contact element arm (12), which is hingedly connected with the transversal arm (17). 13. Contact element of claim 12, wherein recesses (19, 20) are formed in transversal arm (17) separating the contact element arm from the longitudinally extending arms (15, 16). 14. A contact element (10) adapted to provide an electrical connection between a first contact zone of a smart card and a second contact zone provided on another component, for instance on a printed circuit board, said contact element comprising: a first termination section 17 adapted for being fixedly connected to and for contacting said second contact zone, a contact section 127 adapted to resiliently contact said first contact zone, a substantially rectangular frame (11) having first and second elongate arms (15, 16) which are connected by first and second transversal arms (17, 18), said arms defining an elongate opening (40) there between, wherein said first transversal arm defines said first termination section, an elongate contact element arm (12) having a first end and a second end, said first end being hingedly connected to said first transversal arm, said contact arm (12) projecting from said first transversal arm (17) into the direction of said elongate opening (40) and ending in said second free end which is located closer to that second transversal arm (18) than said first transversal arm (17), said second free end forming said second termination end, said contact arm (12) being movable between an unactuated position which no electrical connection is provided and an actuated position in which said electrical connection is provided, said contact arm being bent upwardly with respect to a plane defined by the upper surfaces of said first end, second elongate arms such that the free end forming the first termination end is spaced from said plane in the unactuated position. 15. A smart card connector adapted to receive a smart card having a plurality of first contact zones, said connector comprising: a printed circuit board having a plurality of second contact zones, a plurality of contact elements, and adapted to provide a galvanic electrical connection between said first contact zones of said smart card and the second contact zones provided on said printed circuit board, said contact element comprising: a first termination end adapted for being fixedly connected to and for contacting said second contact zone, a second termination end adapted to resiliently contact said first contact zone, a substantially rectangular frame (11) having first and second elongate arms (15, 16) which are connected by second transversal arms (17, 18), said arms defining an elongate opening (40) there between, and said first transversal arm defining said first termination end, an elongate contact arm (12) having a first end and a second end, said first end being hingedly connected to said first transversal arm, said contact arm (12) projecting from said first transversal arm (17) into the direction of said elongate opening (40) and ending in said second free end which is located closer to that second transversal arm (18) than said first transversal arm (17), said second free end forming said second termination end, said contact arm (12) being movable between an unactuated position which no electrical connection is provided and an actuated position in which said electrical connection is provided, said contact arm being bent upwardly with respect to a plane defined by the upper surfaces of said first end, second elongate arms such that the free end forming the first termination end is spaced from said plane in the unactuated position. 16. A smart card connector adapted to contact a smart card having a plurality of first contact zones, said connector comprising: a component of an apparatus using said smart card connector; a plurality of contact elements (10) adapted to provide a galvanic electrical connection between said first contact zones of the smart card and second contact zones provided on said component; said contact element comprising: a first termination end adapted for being fixedly connected to and for contacting said second contact zone, a second termination end adapted to resiliently contact said first contact zone, a substantially rectangular frame (11) having first and second elongate arms (15, 16) which are connected by second transversal arms (17, 18), said arms defining an elongate opening (40) there between, and said first transversal arm defining said first termination end, an elongate contact arm (12) having a first end and a second end, said first end being hingedly connected to said first transversal arm, said contact arm (12) projecting from said first transversal arm (17) into the direction of said elongate opening (40) and ending in said second free end which is located closer to that second transversal arm (18) than said first transversal arm (17), said second free end forming said second termination end, said contact arm (12) being movable between an unactuated position which no electrical connection is provided and an actuated position in which said electrical connection is provided, said contact arm being bent upwardly with respect to a plane defined by the upper surfaces of said first end, second elongate arms such that the free end forming the first termination end is spaced from said plane in the unactuated position.

Inventors: BRAUN GERHARD, RUMPEL JOCHEN, BRAUN, GERHARD, RUMPEL, JOCHEN
Applicants: AMPHENOL TUCHEL ELECT, BRAUN GERHARD, RUMPEL JOCHEN, AMPHENOL-TUCHEL ELECTRONICS GMBH, BRAUN, GERHARD, RUMPEL, JOCHEN
Application year: 2001
Main classification: H01R13
IPC codes: G06K7, H01R12, H01R13, H01R43