Abstract:
A smart card interface that allows data to be transferred between a smart card and an external data device. The smart card interface receives a smart card having at least one card electrical contact, and comprises at least one roller that rotates when the smart card interface receives the smart card.

Description:
FIELD OF THE INVENTION 
     The invention relates to smart card interface arrangements and particularly, although not exclusively, to smart card interface arrangements adapted to connect smart cards complying with International Standard ISO 7816 to external data devices, such as computers. 
     DESCRIPTION OF THE RELATED ART 
     Smart cards are an extension of conventional plastic cards having a magnetic strips on which information is stored. Such conventional plastic cards are commonly used for bank and credit cards. Smart cards usually contain a microprocessor chip which is capable of storing information and which communicates with the outside world by means of a number of electrical contacts provided on the card. International Standard ISO 7816 sets out a number of specifications relating to the design and layout of smart cards. 
     Smart card interface arrangements allow the smart card to interface with an external data device, such as a computer. However, known smart card interface arrangements all cause wear and degradation of the smart card when used repeatedly over a period of time. This is because of friction between the card and electrical contacts within the interface arrangement, or between the card and biasing elements within the interface arrangement, when the card is inserted into, and removed from, the interface arrangement. 
     For example, the electrical contact may be a raised metallic projection, which tends to scratch the card and the card&#39;s electrical contacts as the card is inserted. Similarly, the biasing element may be a simple resilient projection made of plastics material, adapted to press the card towards the electrical contacts of the interface arrangement, which can also cause wear to the card. In addition, such a biasing element suffers from the disadvantage that it does not apply pressure uniformly across the card, and over time the card may become warped as a result. 
     SUMMARY OF THE INVENTION 
     The invention seeks to overcome at least some of the disadvantages of the prior art. 
     According to the invention there is provided a smart card interface arrangement for allowing data to be transferred between a smart card and an external data device, said arrangement being adapted to receive a smart card having at least one card electrical contact, and comprising at least one roller arranged to rotate when said arrangement receives said smart card. 
     An advantage of such a roller is that it reduces friction on the smart card when the smart card is moved in and out of the interface arrangement. 
     In one embodiment of the invention said roller is an electrical contact roller and is provided with at least one roller electrical contact adapted to rotate with said electrical contact roller and make electrical contact with said card electrical contact on said smart card. 
     In an alternative embodiment of the invention said roller is a biasing roller adapted to apply a force to the opposite side of said smart card to said card electrical contact. 
     In a further embodiment of the invention, the smart card interface arrangement is provided with both said electrical contact roller and said biasing roller. 
     At least part of the biasing roller may be formed from a pliable and/or resilient material adapted to deform to some degree when said smart card is received by the interface arrangement. 
     The biasing roller may be spring-loaded, and may be rotatably mounted about a movable axis which is biased towards said smart card when said smart card is received by the interface arrangement. 
     The electrical contact roller may be provided with a number of roller electrical contacts, such as four. 
     In one embodiment of the smart card interface arrangement, the electrical contact roller is provided with eight roller electrical contacts. 
     The electrical contact roller may be provided with a friction member adapted make contact with said smart card and cause said electrical contact roller to rotate when said smart card is moved. 
     Preferably, the or each roller electrical contact is provided with a fixed electrical contact which is adapted for connection (directly or indirectly) to said external data device, and with which said roller electrical contact continues to make electrical contact even when said electrical contact roller rotates. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will now be more particularly described, by way of example only, with reference to the accompanying drawings, in which: 
     FIG. 1 is an exploded view of a smart card interface arrangement comprising upper and lower parts; 
     FIG. 2 is a perspective view of an electrical contact roller of the interface arrangement; 
     FIG. 3 is a perspective view of the interface arrangement from above, showing the upper and lower parts connected together; 
     FIG. 4 is a perspective view of the interface arrangement from below, showing the upper and lower parts connected together; and 
     FIG. 5 is an enlarged view showing part of the lower part of the interface arrangement in greater detail. 
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Referring to FIG. 1, the interface arrangement  1  comprises an upper part  2  and a lower part  4 . The upper part  2  comprises an upper support structure  6  moulded from plastics material, and defining an opening  8  adapted to support a biasing roller  10 , comprising a central spindle  12  and an outer friction sleeve  14 . The central spindle  12  can be formed from any suitable rigid material, for example metal or plastics material, and the outer friction sleeve  14  can be formed from any resilient or flexible material which will grip a smart card (not shown), for example fluorosilicone, or nitrile rubber. The friction sleeve  14  fits over the central spindle  12 , which is mounted within the opening  8  by means of two spindle supports which are integrally moulded as part of the upper support structure  6 . The biasing roller  10  is held in position by two metal spring fingers  18 , as can be seen more clearly in FIG.  3 . The spring fingers  18  are supported within support housings  20 , which are integrally moulded as part of the upper support structure  6 . The ends of the central spindle  12  are free to move vertically within the spindle supports  16 , and the spring fingers  18  ensure that the biasing roller  10  is biased towards the smart card, which is inserted between the upper part  2  and lower part  4  during operation. 
     The lower part  4  comprises a lower support structure  22 , two electrical contact rollers  24 , and eight fixed electrical contacts  26 . 
     The lower support structure  22  is integrally moulded from plastics material, and comprises four recesses  28  adapted to engage with four projections  30  provided on the upper support structure  6 , when the upper and lower parts  2  and  4  are brought together. The lower support structure  22  is also provided with two apertures  32  adapted to receive the two electrical contact rollers  24 , and two sets of eight grooves  34 , each adapted to receive up to eight fixed electrical contacts  26 . 
     The structure of each electrical contact roller  24  is shown in greater detail in FIG.  2 . Each electrical contact roller  24  comprises a central spindle  36 , on which are mounted four roller electrical contacts  38 , and a friction member  40 . The roller electrical contacts  38  are formed from metal, and the friction member  40  is formed from fluorosilicone, or nitrile rubber. The two ends  42  of the central spindle  36  are of circular cross-section, and adapted to be housed in, and rotate within, suitable mountings on the lower support structure  22 . The remainder of the central spindle  36  is of generally square cross-section, and each roller electrical contact  38  and friction member  40  is provided with a generally square central aperture of complementary cross-section to the central spindle  36 . This ensures that when a smart card is inserted into the interface arrangement, the friction member  40  grips the surface of the smart card and rotation of the friction member  40  drives rotation of the central spindle  36 , and hence rotation of the roller electrical contacts  38 . 
     The fixed electrical contacts  26  can be seen more clearly in FIGS. 4 and 5. Each fixed electrical contact  26  is formed from a single piece of metal, and comprises an indented portion  44  adapted to make contact with a roller electrical contact  38 , and a right-angled connection portion  46  adapted to be plugged into a suitable external data device adapted to exchange information with a smart card inserted into the interface arrangement. Each indented portion  44  is adapted to maintain electrical contact with a roller electrical contact  38  even when the roller electrical contact  38  rotates. 
     During operation of the smart card interface arrangement described above, a smart card is inserted between the upper and lower parts  2  and  4 . Rotation of the biasing roller  10  and the electrical contact rollers  24  ensure that wear of the smart card is minimised. Furthermore, the biasing roller  10  acts to press the smart card against the electrical contact rollers  24 , so that electrical contacts on the smart card achieve a good electrical contact with the roller electrical contacts  38 .