EP0188476A1

EP0188476A1 - Lock working with magnetic mechanisms and coded keycard adapted thereto

Info

Publication number: EP0188476A1
Application number: EP19850903262
Authority: EP
Inventors: Bernhard Hüster; Uwe Urban; Christian Kaiser
Original assignee: DEUTSCHE GERATEBAU GmbH
Current assignee: DEUTSCHE GERATEBAU GmbH
Priority date: 1984-06-27
Filing date: 1985-06-26
Publication date: 1986-07-30
Also published as: WO1986000364A1

Abstract

Afin de rendre invisible de l'extérieur le codage d'une carte de clé avec des points d'informations à lecture magnétique et de ne pas permettre de copie ou de modification sans destruction, tout en autorisant sa lecture sans parties mobiles, on prévoit une plaque (3) recouverte des deux côtés de plaques (1, 2) à base de matériau non magnétisable dans la direction d'introduction avec plusieurs trous découpés (4), disposés entre eux selon un système de clé, pour la lecture et l'identification magnétique. La plaque est à base soit d'un matériau magnétisable, soit d'un matériau non magnétisable, les trous étant dans ce cas remplis d'une substance ferromagnétique (3a) conformément au codage prédéterminé. Pour permettre l'introduction à l'endroit de la carte de clé dans la serrure, les bords des deux plaques de recouvrement sont fixés entre eux dans le plan de l'une des plaques de recouvrement et forment sur un côté frontal une pièce d'embouchure (7) de forme spéciale. A chaque rangée de trous est adjointe une tête de lecture comportant un aimant permanent (9) dirigé vers les rangées de trous, dont les lignes de champ magnétique sont modifiées en fonction de la position d'introduction de la carte de clé dans la serrure grâce au changement entre l'air et le métal. Cela résulte en des modifications brusques de l'induction magnétique qui est transformée par un convertisseur de valeurs de mesure (6) en forme de magnétorésistance en impulsions électriques de commande et de comptage avant d'être amenée à un circuit d'évaluation.In order to make the coding of a key card with information points with magnetic reading invisible from the outside and not to allow copying or modification without destruction, while allowing its reading without moving parts, provision is made for plate (3) covered on both sides with plates (1, 2) based on non-magnetizable material in the direction of introduction with several cut holes (4), arranged between them according to a key system, for reading and magnetic identification. The plate is based either on a magnetizable material, or on a non-magnetizable material, the holes in this case being filled with a ferromagnetic substance (3a) in accordance with the predetermined coding. To allow the key card to be inserted into the lock, the edges of the two cover plates are fixed to each other in the plane of one of the cover plates and form on a front side a piece of mouthpiece (7) of special shape. To each row of holes is added a read head comprising a permanent magnet (9) directed towards the rows of holes, the magnetic field lines of which are modified according to the position of insertion of the key card in the lock by means of to the change between air and metal. This results in abrupt modifications of the magnetic induction which is transformed by a converter of measured values (6) in the form of magnetoresistance into electrical pulses of control and counting before being brought to an evaluation circuit.

Description

Lock working with magnetic means with associated key card

The invention relates to a lock working with magnetic means with an associated, appropriately coded key card, in which the coding in rows in the direction of insertion is partly formed by magnetizable metal, which is invisibly embedded on both sides from the outside, with each row of information points containing a read head on the lock side is assigned to the plug-in level for the key card adjacent to a perpendicularly aligned permanent magnet and a magnetically sensitive semiconductor arranged in series with this in relation to the direction of flow, the output signals of which are converted into electrical voltages and are comparable with a lock-side stored, fixed setpoint coding and if they match with the key-side coding to unlock or release the lock. Such identification key systems serve to prevent the use of special technical facilities or to release a certain group of people using the identification key as a means of identification. Areas of application are therefore goods dispensing devices, liquid dispensing devices, opening devices for doors and barriers or the commissioning of machines and vehicles.

A wide variety of identification key systems are known for such devices.

In addition to the conventional key systems, in which identification keys made of metal are used which, due to their shape, bring about mechanical or electromechanical unlocking, identification key systems are known in which rectangular plug-in cards consist of plastic or of metal foils embedded in plastic, which are inductive, capacitive, optically by light - or infrared light barriers can be scanned. A typical example of this are ID cards according to DE-B 29 20 012, in which the front and back are covered with film.

From DE-A 23 09 658 and DE-A 33 15 204 magnetic data carriers in the form of a check card with laminated or embedded magnetic strips and modeled magnetic code are known, which are read or recorded by a magnetic head. The magnetic stripes of such magnetic cards are relatively thin, which results in the gradual loss of the recorded information over time.

It is known from DE-B 19 31 536, placed on a carrier plate of identification cards with surface patterns to make sprayed ferromagnetic material invisible with an opaque and electrically undetectable material or by mixing or covering.

In a lock to be operated with a key, it is known from DE-B 29 33 453 to provide a key body of rectangular cross-section made of non-magnetic material with upper and lower coding pieces made of soft magnetic material and to insert the key body into a reading head to actuate the lock consisting of two magnets, ring-shaped flux guide pieces and a Hall generator arranged in an air gap of the flow guide pieces. When the bowl body is inserted, a magnetic shunt that is asymmetrical with respect to the Hall generator is produced through the central opening of the yoke, which is delimited by the flux guide pieces and the magnets, the position of the respective shunt in relation to the Hall generator controlling the direction of the magnetic flux through it and the respective one Code number of the associated information point defined. The Hall generator is penetrated by the magnetic flux in one direction and the other time in the opposite direction.

The production of this known lock / key system involves considerable effort both in the shaping of the key body and in the evaluation circuit.

Card-shaped keys, which consist of three layers, the middle layer of which has coding holes and which are covered on the outside by layers which make the coding invisible, are known from GB-A 21 27 4.79 and DE-A 24 61 908 known. In the former, infrared radiation is used to read the coding. Accordingly, the middle layer is impervious to infrared radiation and can be formed, for example, by a perforated metal foil. Each is located on both sides of the insertion slot

Row of holes assigned to infrared transmitter and infrared receiver. The infrared receivers register the holes provided in rows in the middle layer each time a hole passes between the transmitter and the receiver while the key card is inserted into the lock.

In DE-A 24 61 908, the coding is scanned after the key card has been inserted by means of a predetermined pattern of sensors which correspond in size and position to the pattern of the metal dots and the holes in the card. "Small, cylindrical, Cup-shaped blocks made of ferrous material, for example pot cores consisting of iron connections, each of which has windings which act as primary or secondary windings of an iron core transformer and, depending on the presence or absence of a metal point, produce differently strong output signals. The scanning is thus inductive and static.

The scanning of the coding of this known lock / key system requires an extremely high amount of circuitry, since in this statically operating lock / key system each hole or each magnetically readable information point on the key card must be assigned its own iron core transformer with an associated electrical sensor circuit. This effort increases as the number of information points is provided in the key card. A lock / key system of the type mentioned is addressed in US-A 38 96 292. The lock / key system of this known type, however, also works statically, ie the trigger circuit can only be queried and the lock can only be released if the key card has been ascertained when the key card has assumed its inserted position and a switch has been closed as a result.

In this known lock / key system, the inserts embedded in plastic consist of magnetizable metal. In this case, no metal insert is provided in a row that is detected by one of two magnet-sensitive semiconductors that respond to the Hall effect. This series embodies the one of two logical states for the criterion evaluated in the trigger circuit, whether the key card inserted into the lock is a key card that is suitable for the lock or a counterfeit key card, for example made entirely of magnetizable metal.

The invention has for its object to provide a lock / key system in the manner of a key system of the type mentioned, which has the advantages of high strength, an externally covered, also. With frequent use not lost and not duplicable or changeable coding with simple Producibility combined with sheet metal processing machines with the advantage of serial reading of the coding. This object is achieved in that the coding is produced by punching holes in a plate made of magnetizable metal, that the hole pattern is designed such that clock pulses can be derived during insertion of the key card to enable serial reading of the coding and that magnetically sensitive semiconductor is designed as a field plate and a reading head is assigned to each row of holes.

The key-side coding is determined here by the arrangement of the holes running in rows in the key card itself. These holes are arranged in each row within a middle plate, which is preferably made entirely of magnetizable metal, according to an identification key system at certain distances and a certain number from one another. In comparison to inserts made of magnetizable metal according to US Pat. No. 3,896,292, a hole matrix known per se within a plate made of magnetizable metal offers a large number of different combinations and thus a high degree of encryption.

When the hole pattern is read out magnetically, the metal forms a low magnetic resistance between two holes, whereas when the key card is inserted into the lock, the transition between the metal surface and a hole causes a change in the magnetic field line and thus a sudden change in the magnetic induction, which is caused by measured value conversion can be evaluated as electrical counting signals in the field plate penetrated by the magnetic field of the permanent magnet. An intensive flow of field lines through the field plate results when it is arranged, for example glued, in the pole shoe of the permanent magnet corresponding to the N pole with the interposition of a carrier.

Such field plates are subject to the longitudinal Hall effect or Gaussian effect. The charge carriers passing through such semiconductors are laterally deflected by the action of the transverse magnetic field, the path of the charge carriers being extended with an increasing magnetic field and the electrical resistance in the field plate thereby being increased. Electrical count signals obtained in this way are then fed to the evaluation circuit.

In order to insert the key card correctly into the lock, it has an asymmetrical longitudinal cross-section. For this purpose, one of the outer plates covering the plate having the holes has an edge which is crimped in accordance with the thickness of the central plate and which is firmly connected to the edge of the respective other plate. In this case, the flanged edge is formed in a Z-shape and is firmly connected to the edge of the other covering plate with a flat surface, receiving the metal plate between them.

In a further embodiment of the invention, one of the rows of holes is completely covered with holes arranged at equidistant intervals, which form an additional clock track. Regardless of the speed and uniformity with which a user inserts the key card into the slot of the lock, at any time determined by the clock track the associated column of the row is scanned for information points during the insertion of the key card and the key-side coding in the lock-side evaluation or identification circuit is compared with the fixed target value coding stored there. If the codes in the key card and in the evaluation circuit match, the device to which access is to be created can be opened or started.

An embodiment variant is that the plate containing the information points consists of non-magnetizable material and has a plurality of rows arranged, punched holes, which are filled with ferromagnetic material according to the predetermined coding, which with the read head arranged in the lock when inserting the Key card in the lock interacts magnetically.

Embedding flux guide pieces made of ferromagnetic material in key bodies made of non-magnetizable material is known per se from DE-A 31 44 616. The distances between the individual information points of an information track are the same size in this known key body. The value of the individual information points is embodied by flux guide pieces of different magnetic resistance or flux guide pieces with the same magnetic resistance are used and flux guide plates are assigned to them, which form a magnetic shunt. The production of the code elements that can be used in a recess of the key is very complex in this known construction, since the flow guide pieces and flow guide plates embodying the different code values have to be milled, punched and glued. A code-like composition is required for code elements with coding according to a higher-value code.

When using flux guide pieces with different magnetic resistance, different ferromagnetic materials have to be used, shaped and processed in order to obtain the desired coding. This entails a high manufacturing outlay.

Exemplary embodiments of the lock according to the invention that can be operated with a key card are shown in the description in the drawings. Show it

Figure 1 shows a cross section through the key card along the line I-I in Figure 3;

Figure 2 the lock-side insertion opening for the key card;

Picture a top view of the key card;

Figure 4 shows a cross section through the key card inserted into the lock with a reading head assigned to a row of holes when the magnetic field passes through the metal plate of the key card between two holes in each case;

Figure 5 shows a cross section corresponding to Figure 4 when the magnetic field passes through one of the holes in the key card. Figure 6 shows a cross section through the key card on an enlarged scale according to line II in Figure 3 according to a second embodiment;

Figure 7 shows a corresponding cross section according to another embodiment.

As shown in Figures 1 and 3, the key card essentially consists of a plate 3 made of metal with a plurality of rows running in the direction of insertion of the key card and having holes arranged according to a key system 4. The number of holes and the spacing between the holes in each row of holes the coding of the key card in relation to the predetermined lock-side coding.

In the embodiment variant according to image 6, the plate 3 consists of non-magnetizable material, the holes provided in this plate being filled with ferromagnetic material. According to Figure 6, circular metal discs are punched into the holes. As Figure 7 shows, the holes 4 can additionally be filled with iron powder 3a, it being expedient to cover the holes on both sides with a magnetically permeable binder.

On both sides, the plate 3 is covered by plates 1 and 2 made of non-magnetizable material, which makes the hole pattern invisible to the outside. One covering plate 1 has a z-shaped edge which is crimped according to the thickness of the plate 3 and which forms a frame 5 with the flat edge of the plate 2 and after inserting the plate 3 is firmly connected to the edge of the plate 2. This results in an asymmetrical profile of the key card in the longitudinal cross section, which matches the profile of the lock-side insertion opening 8. For correct insertion into the lock, the key card is provided on one end face with a mouthpiece 7, the direction of insertion of the key card into the lock being marked by an arrow pointing towards the mouthpiece 7.

Each row of holes is assigned a reading head, which consists of a permanent magnet 9 and a transducer 6. The permanent magnet 9 is oriented in such a way that its magnetic field emerging from one pole piece penetrates a portion of the slot behind the lock-side insertion opening 8 before it re-enters the other pole piece.

A so-called field plate, which is applied to the one pole shoe and which represents a magnetically controllable resistance, the influence of which is based on the longitudinal Hall effect or Gaussian effect, is used as the measured value converter 6. The charge carriers passing through the semiconductor are deflected laterally by the action of the transverse magnetic field, the path of the charge carriers being extended with an increasing magnetic field. When the key card is inserted into the lock-side opening 8, a hole, that is air, and the metal of the plate 3 located between two holes alternately get into the leakage flux of the permanent magnet. As soon as and as long as metal is guided past the field plate, a signal is generated by deflecting the bias field with the help of the passing metal area between two holes, as is the case with this Figure 4 indicates symbolically. Here, the leakage flux escaping is increased and the field plate resistance increases. However, as soon as a hole 4 of plate 3 is run over the field plate, the leakage flux that emerges is reduced and, as indicated in FIG. 5, gives way to those adjacent to the hole

Metal areas from with the result that the field plate resistance decreases.

Each change between air and metal has a sudden change in the magnetic flux through the field plate acting as a transducer 6, which generates a current surge which is supplied as a counting pulse via lines R to an evaluation circuit, not shown in the drawing.

The logic of the evaluation circuit is chosen so that regardless of the speed and the uniformity with which the key card is inserted into the lock, a correlation is always created between the individual rows of holes. Assuming that the key card with the hole pattern according to Figure 3 is a key card that matches the associated lock, the coding matches the lock-side, predefined coding if, when the key card is inserted into the lock, all four transducers holes in the last Show picture 3 on the line II. When the key card is inserted, the places where there are no holes form information gaps that are noticeable when a counting pulse fails. The left row of holes in the top view of the key card according to Figure 3 is completely filled with holes puts. These holes generate clock signals for which, depending on the position of the key card in the lock, one, two or three counts are generated in the remaining three rows.

Clock and counting pulses can be temporarily stored in the evaluation circuit until the key card has been completely inserted into the opening 8 on the lock side. The comparison then made with the lock-side coding then leads to an actuation of the lock, for example to an opening or activation of the device, if the codes have been found to match.

The invention is not restricted to the exemplary embodiment explained. Versions are conceivable in which an annular permanent magnet is provided instead of a rod-shaped one and has an air gap corresponding to the width of the insertion slot. The magnetic field concentrates on the cross section of the air gap. Instead of holes, the metal plate can be provided with narrow slits running transversely to the direction of insertion, whereby a very precise response of the transducers can be achieved, since there are straight edges between metal and air, on which the magnetic force flow changes abruptly when the key card is moved .

Claims

P A T E N T A N S P R Ü C H E

Lock working with magnetic means with associated, appropriately coded key card, in which the coding running in rows in the direction of insertion is partly formed by magnetizable metal, which is invisibly embedded on both sides from the outside, with each row containing information points being assigned a read head on the lock side, which is connected to the The plug-in level for the key card adjacent to it consists of a permanent magnet aligned perpendicular to it and a magnetically sensitive semiconductor arranged in series with it in the direction of flow, the output signals of which are converted into electrical voltages and can be compared with a lock-set reference value coding stored on the lock side and, if they match the key-side coding for unlocking or release of the lock, characterized in that the coding by punching holes (4) in a plate made of magnetizable metal (3rd ) is generated that the hole pattern is designed such that clock pulses can be derived during insertion of the key card to enable serial reading of the coding and that the magnetically sensitive semiconductor is designed as a field plate (6) and a reading head is assigned to each row of holes.

2. Working with magnetic means lock with associated, appropriately coded key card, in which the coding in rows in the direction of insertion is partially formed by magnetizable metal, which is invisibly embedded on both sides from the outside, with each row of information points on the lock side being assigned a reading head that at the plug-in level for the key card, adjacent to it, consists of a permanent magnet aligned perpendicular to it and a magnetically sensitive semiconductor arranged in series with it in the direction of the flow direction, the output signals of which are converted into electrical voltages and can be compared with a lock set value stored on the lock side and, if they match, with the key side coding serve to unlock or release the lock, characterized in that the plate (3) containing the information points consists of non-magnetizable material and a e has a plurality of rows arranged, punched holes (4), which are filled in accordance with the predetermined coding with ferromagnetic material, which interacts magnetically with the reading head arranged in the lock when the key card is inserted into the lock.

3. lock / key system according to claim 1, characterized in that the holes (4) having plate

(3) consists in its thickness of magnetizable metal.

4. lock / key system according to claim 3, characterized in that the holes (4) having plate

(3) outside covering plates (1, 2) made of non-magnetizable material and one of these plates (1 or 2) one according to the thickness of the holes

(4) having plate (3) has a flanged edge, which is firmly connected to the edge of the other plate (2 or 1).

5. Lock / key system according to claim 4, characterized in that the beaded edge is Z-shaped and forms a frame (5) with the flat edge of the other covering plate, in which the holes (4) having plate ( 3) can be inserted.

6. Lock / key system according to claim 1 or 2, characterized in that the field plate (6) is arranged on the pole shoe of the permanent magnet (9) corresponding to the N pole with the interposition of a carrier, for example glued on.

7. Lock / key system according to claim 1 or 2, characterized in that one of the rows of holes is completely occupied with holes arranged at equidistant intervals as an additional clock track.

8. Lock / key system according to claim 2, characterized in that the holes (4) are filled with punched, circular metal disks.

9. Lock / key system according to claim 2, characterized in that the holes (4) filled with iron powder and covered on both sides with a magnetically permeable binder.