DE3435030A1 - Lock working with magnetic means and having an associated fitting key card - Google Patents

Abstract

So that the coding of a key card having magnetically readable information points can be made invisible from outside and cannot be duplicated or changed without destroying it, but can be read off without movable parts, a perforated plate made of non-magnetisable material, covered on both sides by plates of non-magnetisable material, is provided in the direction of insertion with a plurality of rows of holes for magnetic sensing and identification which are ordered relative to one another according to a code system. The holes are filled with ferromagnetic material, for example circular metal discs and/or iron powder. For the laterally correct insertion of the key card into the lock, the edges of the two cover plates are connected firmly to one another in the plane of one cover plate. Each row of holes is assigned a reading head having a permanent magnet which is aligned with the holes and the magnetic lines of flux of which are varied in dependence on the position of insertion of the key card in the lock during the change between air and metal. This has the effect of abrupt changes in magnetic induction which are converted into electrical counting signals by a measurement transducer designed as a magnetoresistor and which are fed to an evaluation circuit.

Description

Magnetic lock

with associated matching key card The invention relates on a lock that works with magnetic means with the corresponding key card with the features of the preamble of claim 1 according to patent 34 23 714.

The main purpose of the patent is to create a code system to create the keys of which have high strength and with frequent use keep these unchanged, where the coding is covered, therefore by is not visible from the outside and cannot be ducted or changed without destruction can and no moving parts are required to read the code, and the key being produced with the help of simple sheet metal working machines can be.

When solving the Hauptyatents is therefore provided that the key card made of a metal plate and two plates that cover it invisibly on both sides non-magnetizable material, and that the metal plate several in Einführ.richtnng the key card running series of used for magnetic scanning and identification, and has holes arranged according to a key system.

It has been shown that switching between metal and non-magnetizable Material when inserting the key card into the lock also by other means can be brought about to achieve the same effect.

From DE-OS 31 44 616 is a key with a Schlüsselkörpor known from non-magnetizable material, in the flux guide pieces from ferromagnetic Material are embedded, which form at least one InbDrmationssFur and the key secret embodied in the form of an at least two-valued code.

The distances between the individual information points of an information spirit are the same size in this known key body.

The value of the individual information points is determined by flow guide pieces embodied different magnetic resistance or there are flux guide pieces used with the same magnetic resistance and assigned to them flux guide plates, which form a magnetic shunt.

The manufacture of the insertable in a recess of the key Code elements are very complex in the known design, since the different Flux guide pieces and flux guide plates embodying code values are milled, punched and need to be glued. For code elements with coding according to a higher value Code a sandwich composition is required.

When using flux guide pieces each with a different magnetic Different ferromagnetic materials are to be used accordingly, shape and edit to get the encoding you want. This brings a high manufacturing cost.

The object of the present invention is to provide the solution according to the main fatent to continue training and to simplify the known design in terms of production, with the mechanical coding additionally provided in the known design is omitted can.

According to the invention, this object is achieved in that the vibration points containing plate is made of non-magnetizable material and in this Plate provided holes are filled with ferromagnetic material, which with the reading head arranged in the lock when inserting the key card into the Lock interacts magnetically.

When reading out magnetically, the distance and number of holes Given the coding, the metal in the holes forms a low magnetic level Resistance, whereas when the key card is inserted into the lock, the transition a change in the course of the magnetic field lines between the metal and the perforated plate and thus brings about a sudden change in the magnetic induction, what can be evaluated as electrical counting signals by changing the measured values.

By covering the plate with the rows of holes on both sides by means of plates made of non-magnetizable material it is ensured that the holes provided in a certain coding or

the ferromagnetic material filled therein after manufacture a fixed connection between the covering panels become invisible and not can be duplicated.

In an advantageous embodiment of the invention, the holes are punched with, circular metal disks. You can also alternatively or additionally Filled with iron powder and magnetically permeable binding agent on both sides be covered.

Instead of ferromagnetic material, the perforated plate can also be arranged small control magnets, which become permanent magnets are aligned with opposite polarity. The permanent magnet can also flow into stray an induction coil 5 be arranged in the each change between air and An electrical surge is induced in metal. Finally, the key card can be used facing pole piece of the permanent magnet according to the size of the holes or the metal parts inserted therein be tapered.

The read head housed in the lock, which unlocks the to actuating device, for example to release the lock, consists in an advantageous manner of a permanent magnet, whose magnetic field lines be changed serially when the key card is inserted, with the changes the magnetic induction by a Meßwertum iörmer in the form of a magnetic controllable resistance effective field plate in electrical signals can be bypassed.

Such FeldFLatten 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, whereby the path of the charge carriers lengthened with increasing magnetic field and the electric Resistance in the field plate is thereby increased. Electric power gained in this way Counting signals are then fed to an evaluation circuit. So that the field plate is detected by the full magnetic field, it is at the one corresponding to the north pole Pole shoe of the permanent magnet arranged with the interposition of a carrier, so that the magnetic flux exiting on this pole side affects the measured value very focused.

In a further embodiment of the invention, the electrical counting signals the field plate according to their coding in an evaluation or identification circuit compared with a fixed Codieruny stored there after the key card has been inserted into the lock. If they match the hole pattern grids the lock is unlocked in the perforated plate of the key card.

An example of the Ausiuhrungsbeispiel explained in more detail in the description with a key card operated lock according to the invention is in the Drawings reproduced. It shows picture la a cross section through the key card on an enlarged scale along the line I-I in Figure 3 according to an exemplary embodiment; Figure lb a cross section according to a modified exemplary embodiment from; picture 2 the lock-side insertion opening for the key card; Fig. 3 is a top view on the key card; Figure 4 shows a cross-section through the one introduced into the lock Key card with a reading head assigned to a row of holes when passing through the magnetic field through a hole filled with ferromagnetic material; Fig. 5 shows a cross-section corresponding to Fig. 4 during the passage of the magnetic Field through the perforated plate between two holes.

As the pictures la, Ib and 3 show, the key card is in the essentially of a plate 3 made of non-magnetizable material with several in the direction of insertion of the key card rows of according to a key system holes arranged to one another 4. By the number of holes and the distances between The coding of the key card with respect to the predetermined lock-side coding established. The holes 4 are each ferromagnetic Material filled out. According to picture la this can be made of punched circular metal disks exist or alternatively or, according to Fig. Ib, additionally be iron powder 3a.

The perforated plate 3 is made up of plates 1 and 2 on both sides Covered non-magnetizable material, whereby the hole pattern to the outside becomes invisible. The one covering plate 1 has one corresponding to the thickness the perforated plate 3 beaded, z-shaped edge, which with the flat edge of the plate 2 forms a frame 5 and after inserting the perforated Plate 3 is firmly connected to the edge of the plate 2. This results in the Longitudinal cross-section an asymmetrical profile of the key card, which with the Profile of the lock-side insertion opening 8 matches. To the backward agreement In the lock, the key card is provided with a mouthpiece 7 on one face, the direction of insertion of the key card into the lock through one to the mouthpiece 7 pointing pisil is marked.

Each row of holes is assigned a read head consisting of a permanent magnet 9 and a Meßwertumer 6 consists. The permanent magnet 9 is oriented so that its magnetic field emerging from one pole piece forms part of the slot behind the lock-side Einfährö ffhung 8 penetrates before it on the other pole piece re-enters.

As a measured value transducer 6, one is applied to one pole piece FeldElatte used, which represents a magnetically controllable resistor, whose Can be influenced on the longitudinal Hall effect or

Gaussian effect is based. The charge carriers passing through the semiconductor are laterally deflected by the action of the transverse magnetic field, whereby the path of the charge carriers increases as the magnetic field increases. When inserting the key card in the lock-side opening 8 comes alternately with a hole filled ferromagnetic material and the one between two holes, non-magnetizable material of the plate 3 in the leakage flux of the permanent magnet. As soon as and as long as metal is led past the field plate, a signal is given deflection of the bias field with the help of the eating metal area generated, as Figure 4 symbolically indicates. Here the leaking leakage flux and the field batten resistance increases. However, as soon as the field plate of an area between two holes 4 of the perforated plate 3 is passed over, is the emerging leakage flux is reduced and softens, as indicated in Figure 5 the hole with the result that the field plate resistance decreases.

Every change between air and metal has a sudden change of the magnetic flux through the field plate acting as a measured value converter 6 Result, whereby a current surge is generated, which as a counting pulse over lines R a Evaluation circuit, not shown in the drawing, is supplied.

The logic of the evaluation circuit is chosen so that it is independent of the speed and uniformity with which the key card is in the lock is introduced, there is always a correlation between the individual rows of holes is created. Suppose it is the key card with the hole pattern according to Figure 3 for a key card that matches the associated lock, the coding corresponds to the permanently specified coding on the lock side, if, when the key card is inserted into the lock, all four transducers are last Show the holes of the line lying on the section line I-I in Figure 3. When pushing in On the key card, the places where no holes are provided form information gaps, which make themselves noticeable through the failure of a counting component. The left row of holes The top view of the key card according to Figure 3 is completely filled with holes. These holes generate clock signals, which depend on the position of the key card in the lock one, two or three counting pulses are generated in the other three rows.

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

In the holes or slots or in their place can in the metal plate 3 small control magnets can also be arranged, which are opposite to the permanent magnet polarized and their leakage flux when passing the permanent magnet its bias is superimposed, which also changes the Field flattening resistance arise or can be evaluated.

From executions are also conceivable in which in the stray flux of the permanent magnet an induction coil is arranged, in which with each change between air and An electrical surge is induced in metal.

Finally, the pole piece of the permanent magnet facing the key card can according to the intended size of the holes or

of the metal parts inserted therein be tapered to a To achieve the strongest and most focused field possible in the sense of a magnetic lens.

Claims (10)

Patent pending. Lock working with magnetic means with the matching key card, the one being housed in a housing Lock has a read head that opens when the key card is inserted into the Lock generated magnetic field changes responds, and wherein the key card magnetically readable information points and two outer, the information points invisible having covering plates made of non-magnetizable material and between them two plates a plate carrying the information points with several in the direction of insertion the key card running rows of to each other according to a key system ordered holes is provided according to patent 34 23 714, characterized in that, that the disc (3) containing the information points is made of non-magnetizable Material and the holes (4) provided in this plate (3) with ferromagnetic Material are filled, which with the read head arranged in the lock when Pushing the key card into the lock interacts magnetically. 2. Lock fir key card according to claim 1, characterized in that that the holes (4) are ausüilt with punched, circular metal disks. 3. Lock you key card according to claim 1, characterized in that that the holes (4) are grooved with iron powder and magnetically permeable on both sides Binders are covered. 4. Lock air key card according to claim 1, characterized in that that one of the two plates (1 or 2) covering the perforated plate (3) has a corresponding to the thickness of the perforated plate (3) has flanged edge, the is firmly connected to the edge of the other plate (2 or 1). 5. lock for key card according to claim l, characterized in that that for serial coding the key card assigned to the lock with different Hole patterns in the plate (3) is provided and that each row of holes has a reading head assigned. 6. Lock iür key card according to claim, characterized in that that the read head is aligned perpendicular to the key card to be inserted Has permanent magnets (9) on which a Menwertum £ ormer (6) in the form of a magnetically controllable resistance effective field plate is attached, which the Magnetic leakage flux changes when the key card is inserted into the lock converted into electrical counting signals. 7. lock ftfr key card according to claim 6, characterized in that that the electrical counting signals of the field plate according to their coding in an evaluation circuit be compared with a fixed coding secured there and if they match the lock with the hole pattern in the perforated plate (3) of the key card is unlocked. 8. Lock iür key card according to claim 1, characterized in that that in the holes (4) of the perforated plate (3) arranged small control magnets are aligned with opposite polarity to the permanent magnet (9). 9. Lock for key card according to claim 6, characterized in that that an induction coil is arranged in the leakage flux of the permanent magnet (9), in which an electrical surge is induced with every change between air and metal will. 10. lock 5k key card according to claim 6, characterized in that that the pole piece of the permanent magnet (9) facing the key card accordingly the size of the holes (4) or the metal parts inserted therein tapered is.