Chip card reading apparatus

An apparatus for reading chip cards with at least one channel receiving a chip card and having at least one read head, the apparatus being detachably insertable into a receiving shaft intended for receiving modules in a computer, whereby in the channel for receiving at least one chip card two back limiting walls are provided in two different planes which are disposed at different distances from the opening of the channel so that two chip cards disposed directly one above the other are insertable into the channel by different lengths, permits insertion of two chip cards into a receiving channel in simple fashion in that a prestressing device is provided which is so prestressed that upon insertion into the empty apparatus the lower of the two chip cards is pressed into the lower plane in the direction out of the plane of the upper of the two different planes, the prestressing device being disposed on the upper limiting wall of the upper of the two different planes.

FIELD OF THE INVENTION
 This invention relates to an apparatus for reading chip cards with at least
 one channel receiving a chip card and having at least one read head, the
 apparatus being detachably insertable into a receiving shaft intended for
 receiving modules in a computer, whereby in the channel for receiving at
 least one chip card two back limiting walls are provided in two different
 planes disposed at different distances from the opening of the channel so
 that two chip cards disposed directly one above the other are insertable
 into the channel by different lengths.
 BACKGROUND OF THE INVENTION
 The prior art shows a plurality of different chip cards which are used for
 credit purposes, for telephoning or for security tasks and information
 transmission. The chip cards usually have standard credit card format and
 are read in chip card readers designed in many different ways. Separate
 chip card readers are known for this purpose which are insertable into a
 receiving shaft in a computer to transfer chip card data to the computer.
 However, it is necessary or advantageous for diverse applications to
 connect two separate chip cards with a computer and make a connection
 between the particular cards.
 It is known from EP 0 696 010 A1 to use two chip cards simultaneously with
 a chip card reader, the cards being insertable into the reader at
 different depths. The two cards are also insertable into a common
 receiving channel in which a projection is provided to cause defined
 positioning of the cards within the receiving channel. However, it can
 happen that a first inserted card gets caught on the projection, thereby
 impeding the insertion process.
 GB 2 298 743 A discloses a chip card reading apparatus of the
 abovementioned kind. In this known apparatus as well; however, when one
 chip card is inserted into the corresponding channel there is always a
 possibility of the card getting caught on the projection or on the
 shoulder of the limiting wall provided for another card, which can make an
 insertion process difficult and tedious and damage the card.
 The problem of the invention is to provide a chip card reading apparatus
 which permits two chip cards to be inserted into a receiving channel in
 simple fashion.
 SUMMARY OF THE INVENTION
 This problem is solved according to the invention by a prestressing device
 which is so prestressed that upon insertion into the empty apparatus the
 lower of the two chip cards is pressed into the lower plane in the
 direction out of the plane of the upper of the two different planes, the
 prestressing device being disposed on the upper limiting wall of the upper
 of the two different planes.
 Preferred developments of the invention are the subject of the subclaims.

DESCRIPTION OF BEST MODE OF THE INVENTION
 In the inventive apparatus, providing a channel with two back limiting
 walls disposed in two different planes at different distances from the
 opening of the channel makes it possible for the chips of two chip cards
 inserted into the reading apparatus to come to lie so far apart in their
 particular end position, in which they adjoin the particular limiting wall
 of the channel, that they are each contactable with a read head disposed
 above a card. Simultaneously, the fact that the two chip cards project
 outwardly of the reading apparatus by different lengths when inserted in
 the reading apparatus ensures that at least one of the two chip cards
 remains recognizable and identifiable in the inserted position.
 The feature of providing a prestressing device which is so prestressed that
 upon insertion into the empty apparatus the lower of the two chip cards is
 pressed into the lower plane in the direction out of the plane of the
 upper of the two different planes, the prestressing device being disposed
 on the upper limiting wall of the upper of the two different planes, makes
 it quintessentially possible to provide an apparatus in which the action
 of the prestressing device prevents one chip card inserted into the
 channel for receiving at least one chip card from coming against the wrong
 one of the two back limiting walls disposed in two different planes at
 different distances from the opening of the channel.
 According to a preferred embodiment of the inventive reading apparatus, a
 prestressing device is provided which is so prestressed that, upon
 insertion into the empty apparatus, the lower of the two chip cards is
 pressed into the lower plane in the direction out of the plane of the
 upper of the two different planes. Alternatively, a prestressing device is
 provided according to the invention which is so prestressed that, upon
 insertion into the empty apparatus, the upper of the two chip cards is
 pressed into the upper plane in the direction out of the plane of the
 lower of the two different planes. This permits the inventive reading
 apparatus to read either only one chip card or both chip cards
 simultaneously.
 If a prestressing device is provided which is so prestressed that upon
 insertion into the empty apparatus the lower of the two chip cards is
 pressed into the lower plane in the direction out of the plane of the
 upper of the two different planes, the prestressing device is preferably
 disposed on the upper limiting wall of the upper of the two different
 planes. The prestressing device of the inventive reading apparatus is in
 this case preferably a leaf spring whose two ends adjoin the upper
 limiting wall of the upper of the two different planes.
 This measure permits the prestressing device to be disposed at a place from
 where it acts directly in the direction of the position into which a first
 introduced chip card is to be guided.
 According to this embodiment, the inventive reading apparatus is designed
 so that, in the inserted state of only the lower chip card, the chip of
 said card contacts with only a first read head. In the inserted state of
 both chip cards, the chip of the lower card contacts with only the first
 read head according to this embodiment, and the chip of the upper card
 contacts only with a second read head, the read heads being spaced apart
 in accordance with the distance of the two back limiting walls disposed in
 different planes.
 However, if a prestressing device is provided which is so prestressed that,
 upon insertion into the empty apparatus, the lower of the two chip cards
 is pressed into the lower plane in the direction out of the plane of the
 upper of the two different planes, the prestressing device is preferably
 disposed on the lower limiting wall of the lower of the two different
 planes. The prestressing device of the inventive reading apparatus is in
 this case preferably a leaf spring whose two ends adjoin the lower
 limiting wall of the lower of the two different planes.
 This measure also permits the prestressing device to be disposed at a place
 from where it acts directly in the direction of the position into which a
 first introduced chip card is to be guided.
 According to this embodiment, the inventive reading apparatus is designed
 so that, in the inserted state of only the upper chip card, the chip of
 said card contacts with only a first read head. In the inserted state of
 both chip cards, the chip of the upper card contacts with only the first
 read head according to this embodiment, and the chip of the lower card
 contacts only with a second read head, the read heads being spaced apart
 in accordance with the distance of the two back limiting walls disposed in
 different planes.
 The inventive apparatus has in its front area preferably two centering
 elements for positioning the operating position of the chip card in the
 reading apparatus. The centering elements can be of straight form, or they
 can be of bent form in accordance with the radius of curvature of the
 corners of an ISO IC card. This obtains reliable positioning of the
 particular chip cards in their operating position.
 In the inventive reading apparatus, insertion of the at least one chip card
 into the apparatus can be facilitated if guide belts are provided on the
 side surfaces of the apparatus for guiding the chip card in the channel
 and guiding the apparatus in the receiving shaft.
 Alternatively, insertion of the at least one chip card into the reading
 apparatus can be facilitated if the apparatus has a front area insertable
 into the receiving shaft of a computer, and a back area shorter than the
 front area, the height and the width of the back area being greater than
 those of the receiving shaft of the computer, and guide means for chip
 cards to be inserted into the first part being provided in the back area.
 The inventive chip card reading apparatus will be explained in the
 following with reference to a preferred embodiment shown in the FIGURE of
 the drawing, whereby:
 FIG. 1 shows an embodiment of the inventive reading apparatus for inserting
 two chip cards in an oblique top view.
 In inventive chip card reading apparatus 3 shown in FIG. 1, two chip cards
 10, 20 are introducible into entry opening 14 of channel 4, 4', cards 10,
 20 coming to lie directly one above the other in channel 4, 4' in the
 introduced state. Channel 4, 4' has in two different planes two back
 limiting walls 8, 8' disposed at different distances from entry opening 14
 of channel 4 so that the two cards 10, 20 are insertable into channel 4 by
 different lengths. In the inserted state of card 20, chip 21 contacts with
 read head 5, whereby if card 10 is simultaneously inserted chip 11
 contacts with read head 5'. On the upper limiting wall of channel 4' there
 is leaf spring 7 which causes card 20 to be pressed upon insertion into
 empty reading apparatus 3 in the direction of channel 4 in the direction
 away from limiting wall 8. During insertion, cards 10, 20 are guided
 laterally by belts 6, 6' which are disposed on the side surfaces of
 reading apparatus 3 and extend up to about 3/4 of the length of the side
 surfaces of the reading apparatus. Belts 6, 6' moreover cause reliable
 insertion of reading apparatus 3 into a receiving shaft (not shown) in a
 computer.