IC card rigidized cover

Abstract: A cover assembly for an IC card includes top and bottom covers (52, 54) with overlapping side rails (70, 80). At each side of the card, a downwardly-extending top side rail (70) lies facewise adjacent to an upwardly extending bottom side rail (80), and a layer (90) of solder is sandwiched between the rails and is bonded to each of them. The solder layer extends along most of the height of each cover side, so the two rails and the solder layer between them serve as a single rigid beam. The cover assembly can be, instead, spot welded at a plurality of locations at each side of the card, to weld the two rails facewise together.

Description: IC cards are usually constructed in accordance with JEIDA standards, wherein one type of card has a length of 85,6mm (3,370"), a card width of 54mm (2.126"), and a card thickness of 4,826mm (0.190"). Each card includes a circuit board with electronic components thereon, a body that includes front and rear connectors (at least the front connector has a row of contacts) and possibly a frame extending between the connectors, and a sheet metal cover assembly. The sheet metal cover assembly preferably extends almost completely around the circuit board, except at the front and rear ends of the board where the front and rear connectors lie. A manufacturer of parts for an IC card supplies the body and cover, while the customer manufacturers the circuit board. The customer, or assembler, mounts a circuit board on the body and mounts the cover assembly around the combination of circuit board and body. From WO A1 95/14288 an IC card is know, which has a cover assembly including top and bottom metal covers. Both covers having a pair of side rails that each extend substantially vertically from the cover sides, with one of the pairs of rails having a further inwardly bend, which during assembly snaps over the top of the corresponding pair of rails to keep top and bottom cover together. From US A 5,397,857 an IC card is know, which has a cover assembly including top and bottom metal covers each having a plastic frame. The two cover halves are welded together using ultra sonic welding of opposing plastic frame elements in the plane of the circuit board.. One type of sheet metal cover assembly includes top and bottom covers that each comprises a sheet-like part covering the top or bottom of the card, and a pair of side rails. In one arrangement, the bottom edges of the side rails that extend down from the top cover abut the upper edges of the side rails that extend up from the lower cover, and the abutting edges are welded together by a laser beam welder. The cost of a laser beam welder is very high, and many smaller customers cannot afford them. If the top and bottom covers could be securely joined with the use of moderate cost equipment, this would benefit smaller assemblers of IC cards. It would be desirable if the sides of the cover assembly had increased strength against deflection, to rigidize the card. SUMMARY OF THE INVENTION In accordance with one embodiment of the present invention, an IC card and a method for constructing it, are provided, which enable joining of the top and bottom covers of the cover assembly by the use of equipment of moderate cost, while providing cover sides of increased rigidity. Top and bottom covers each have a sheet-like portion covering the top or bottom of almost all of the circuit board, and have side rails. The top side rails that extend downwardly from opposite sides of a top cover part, lie facewise adjacent to corresponding bottom side rails that extend up wardly from opposite sides of a bottom cover part. Instead of soldering or laser beam welding each pair of rails together, they can be spot welded together at a plurality of locations at each side of the card. As a result, the combination of adjacent rails, serves as a thick unitary beam of considerable height, to provide high strength and rigidity. The novel features of the invention are set forth with particularity in the appended claims. The invention will be best understood from the following description when read in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric view of an IC card constructed in accordance with the present invention, and indicating, in phantom lines, a method for completing the assembly. FIG. 2 is an exploded isometric view of the IC card of FIG. 1. FIG. 3 is a sectional view taken on line 3-3 of FIG. 1. FIG. 4 is an enlarged view of a portion of the IC card of FIG. 3. FIG. 5 is a partial sectional view of a prior art cover assembly. FIG. 6 is an isometric view of an IC card constructed in accordance with an embodiment of invention. FIG. 7 is a partial sectional view taken on line 10-10 of FIG. 6. DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 illustrates an IC card 10 which has a front connector 12 for insertion into an electronic device, to connect to contacts in the electronic device. A cover assembly 50 lying around most of the periphery of the card, has opposite cover sides 15, 17. As shown in FIG. 2, the IC card includes a circuit board assembly 14 comprising a board 16 and electronic components 18 thereon. The board has front and rear ends 20, 22 that are mounted on a body arrangement 30 which is formed by front and rear connectors 32, 34. It may be noted that in some IC cards, the body arrangement includes an additional molded plastic frame that extends between the front and rear connectors, although in the embodiment of FIG. 2, the body includes only the front and rear connectors. The circuit board has a row of contact traces or pads 36, 38 at its opposite ends, which engage tails of the contacts 40, 42. In all cases, the front connector 32 has contacts, but only in some cases does the rear connector 34 have contacts. The combination 44 of the circuit board assembly 14 and body 30, is enclosed by a cover assembly 50. The cover assembly 50 includes top and bottom covers 52, 54, that are each formed of bent sheet metal, such as stainless steel. The top cover includes a top part 60 that covers substantially all of the top face 62 of the circuit board. The cover top part has laterally spaced (in direction M) opposite sides 64, 66 and longitudinally spaced (in direction N) opposite ends 67, 68. The top cover also includes a pair of top side rails 70, 72 that each extends substantially downwardly (in direction D) from a different one of the top part sides. The bottom cover 54 is similarly constructed, with a bottom part 74 that covers substantially all of the board bottom face 75. The bottom part has opposite sides 76, 78, and has bottom side rails 80, 82 extending substantially upwardly (in direction U) from each side of the bottom part. FIG. 3 shows the top and bottom covers 52, 54 after they have been completely assembled. Each top side rail such as 70 lies facewise adjacent to a corresponding bottom side rail 80, with a considerable overlap between them. FIG. 4 illustrates a portion of a card that applicant has designed, wherein each cover is formed of stainless steel having a thickness C of 0,152mm {6 mils (1 mil equals one thousandth inch)}. The cover inside height B near the opposite sides of the cover, is about 2,8mm (110 mils). Figure 5 shows a prior art cover arrangement, wherein adjacent edges of the top and bottom side beams M, N abutted and were laser welded together at their abutment P. As mentioned earlier, such laser welding equipment is very expensive, compared to a simple furnace that merely heats the opposite sides of the card. Also, as described above, applicant's provision of overlapping side rails that are bonded together, results in a beam of increased rigidity, with the effective thickness of the beam equal to the thickness of the two rails plus the thickness of the solder layer that lies between them and that is bonded to them. Instead of applying a wide, or tall (in directions U, D) solder strip to the side rails, it would be possible to apply perhaps two narrower (or shorter) solder strips, or even numerous dots of solder. However, that would result in forming beams of lesser strength at each side of the card. Figs. 6 and 7 illustrate another cover assembly 130 which is similar to that of Figs. 1-8, except that the side rails 70A, 80A do not carry solder layers. Instead, the rails are spot welded together by welds 132, 134 at each side of the card. The spot welds such as 132 preferably have a height K of at least half the height A of the bottom rail 80A, and the bottom rail has a height A that is at least half the height B of the inside height of the cover assembly side. Spot welding equipment is much less expensive than laser beam welders (which cost 2.5 to 5 times as much) presently used to join cover halves of IC cards. Thus, the invention provides an IC card apparatus and a cover assembly therefor, where the cover assembly includes top and bottom covers that can be assembled with low cost equipment and that provide rigid side beams at opposite sides of the card. This can be accomplished by forming the top and bottom covers with side rails that overlap and a plurality of welds formed at each of said cover sides on said surfaces that face vertically, each weld joining facewise adjacent locations on one of said top rails and on one of said bottom rails. Each each of said welds preferably extends by a height at least equal to one-half the inside height of the cover sides, so the beam provided by the sandwich of two rails, has a considerable height. The card can be used in any orientation, with terms such as "top" and "bottom" being used herein only to aid in the description of the invention. Although particular embodiments of the invention have been described and illustrated herein, it is recognized that modifications and variations may readily occur to those skilled in the art.

Claims: Claims for the following Contracting States : FI, IT, SE An IC card apparatus which comprises a circuit board assembly (14) that includes a board (16) with front and rear ends (20, 22) with said front end having a row of conductive traces (36), a body arrangement (30) that is fastened to said circuit board and that includes a front connector (32) having a row of contacts (40) engaged with said row of conductive traces, and an electrically conductive cover assembly (50) extending largely around said circuit board and having opposite cover sides, with said cover assembly (50) includes top and bottom covers (52, 54), said horizontally extending top cover having a top part (60) that covers most of said circuit board and that has opposite top part sides (64, 66), and said top cover having top side rails (70, 72, 70A) that each extends substantially downwardly from a different one of said top part sides, and with said bottom cover having a horizontally extending bottom part (74) that lies below most of said circuit board and that has opposite bottom part sides (76,78), and said bottom cover having bottom side rails (80, 82, 80A) that each extends substantially upwardly from one of said bottom part sides, characterized by : said top and bottom rails at each of said cover sides overlapping and lying facewise adjacent to each other to form a pair of facewise adjacent rails; having adjacent surfaces (92, 94) that face vertically; a plurality of welds (132, 134) formed at each of said cover sides on said surfaces (92, 94) that face vertically, each weld joining facewise adjacent locations on one of said top rails (70A) and on one of said bottom rails (80A). The apparatus described in claim 1 wherein: each of said bottom rails extends along a predetermined height (A) along which the bottom rail lies facewise adjacent to the corresponding top rail, and each of said welds has a height (K) that is at least 50% of said predetermined height. A method of constructing an IC card apparatus as defined in claim 1, said method including the steps of: forming an electrically conductive top cover (52) with a largely horizontally-extending top part (60) having a width greater than that of said board and having opposite sides (64, 66), with said top cover having top side rails (70A) that each extends substantially downwardly from a different one of said top part sides, with said top side rails having inner faces that face each other; forming an electrically conductive bottom cover (54) with a substantially horizontally-extending bottom part (74) having opposite sides (76, 78), with said bottom cover having bottom side rails (80A) that each extends substantially upwardly from a different one of said bottom part sides, with said bottom rails having outer faces that face away from each other; placing said covers so said bottom part of said bottom cover lies under said circuit board arrangement and said bottom side rails lie substantially beyond opposite sides of said circuit board arrangement, and so said top part of said top cover lies over said circuit board arrangement and said top side rails lie beyond and facewise against said bottom side rails, characterized by said top and bottom rails at each of said cover sides overlapping and lying facewise adjacent to each other to form a pair of facewise adjacent rails; having adjacent surfaces (92, 94 ) that face vertically; forming a plurality of welds (132, 134) at each of said cover sides on surfaces (92, 94) that face vertically, each weld joining facewise adjacent locations on one of said top rails (70A) and on one of said bottom rails (80A). Claims for the following Contracting States : DE, FR, GB An IC card apparatus which comprises a circuit board assembly (14) that includes a board (16) with front and rear ends (20, 22) with said front end having a row of conductive traces (36), a body arrangement (30) that is fastened to said circuit board and that includes a front connector (32) having a row of contacts (40) engaged with said row of conductive traces, and an electrically conductive cover assembly (50) extending largely around said circuit board and having opposite cover sides, with said cover assembly (50) includes top and bottom covers (52, 54), said horizontally extending top cover having a top part (60) that covers most of said circuit board and that has opposite top part sides (64, 66), and said top cover having top side rails (70, 72, 70A) that each extends substantially downwardly from a different one of said top part sides, and with said bottom cover having a horizontally extending bottom part (74) that lies below most of said circuit board and that has opposite bottom part sides (76,78), and said bottom cover having bottom side rails (80, 82, 80A) that each extends substantially upwardly from one of said bottom part sides, characterized by : said top and bottom rails at each of said cover sides overlapping and lying facewise adjacent to each other along the complete height (A) of the bottom side rail (80A) to form a pair of facewise adjacent rails; having adjacent surfaces (92, 94 ) that face vertically; a plurality of welds (132, 134) formed at each of said cover sides on said surfaces (92, 94) that face vertically, each weld joining facewise adjacent locations on one of said top rails (70A) and on one of said bottom rails (80A). The apparatus described in claim 1 wherein: each of said bottom rails extends along a predetermined height (A) along which the bottom rail lies facewise adjacent to the corresponding top rail, and each of said welds has a height (K) that is at least 50% of said predetermined height. A method of constructing an IC card apparatus as defined in claim 1, said method including the steps of: forming an electrically conductive top cover (52) with a largely horizontally-extending top part (60) having a width greater than that of said board and having opposite sides (64, 66), with said top cover having top side rails (70A) that each extends substantially downwardly from a different one of said top part sides, with said top side rails having inner faces that face each other; forming an electrically conductive bottom cover (54) with a substantially horizontally-extending bottom part (74) having opposite sides (76, 78), with said bottom cover having bottom side rails (80A) that each extends substantially upwardly from a different one of said bottom part sides, with said bottom rails having outer faces that face away from each other; placing said covers so said bottom part of said bottom cover lies under said circuit board arrangement and said bottom side rails lie substantially beyond opposite sides of said circuit board arrangement, and so said top part of said top cover lies over said circuit board arrangement and said top side rails lie beyond and facewise against said bottom side rails, characterized by said top and bottom rails at each of said cover sides overlapping and lying facewise adjacent to each other along the complete height (A) of the bottom side rail (80A) to form a pair of facewise adjacent rails; having adjacent surfaces (92, 94) that face vertically; forming a plurality of welds (132, 134) at each of said cover sides on surfaces (92, 94) that face vertically, each weld joining facewise adjacent locations on one of said top rails (70A) and on one of said bottom rails (80A).

Inventors: BETHURUM GARY CAIN, KNIGHTS ANTHONY JOHN, BETHURUM, GARY CAIN, KNIGHTS, ANTHONY JOHN
Applicants: ITT MFG ENTERPRISES INC, ITT MANUFACTURING ENTERPRISES, INC.
Application year: 1996
Main classification: H05K5
IPC codes: B42D15, G06K19, H05K5