WO1983001642A1

WO1983001642A1 - Key with a non magnetizable body containing conductor parts of ferromagnetic material

Info

Publication number: WO1983001642A1
Application number: PCT/DE1982/000213
Authority: WO
Inventors: Branko R Perkut; Leopold Anetseder
Original assignee: Perkut, Branko, R.; Leopold Anetseder
Priority date: 1981-11-10
Filing date: 1982-11-05
Publication date: 1983-05-11
Also published as: DE3144616A1; EP0093134A1

Abstract

The ferromagnetic conductor parts (3) are arranged at predetermined locations on the body of the key (1) of non magnetizable material. The parts form at least one information line which contains the secret of the key in the form of at least a double code. The associated lock comprises a reading device (4) provided with at least one magnetic induction field with a permanent magnet (5) and with a magnet-sensitive element (7). The conductor parts close the magnetic circuit according to the code so that the magnetic flux traversing the magnet-sensitive element has values which differ according to the different values of the code. In order to prevent recognition from outside of the key coding or to prevent determination of the same by simple detection means, the different coding values are embodied by conductor parts having a different magnetic resistance or a plate conducting a flux forming a magnetic shunt circuit is associated to the conductor pieces. The conductor pieces are magnetically connected inside the key body with the flux conductor plate according to the code value, either directly or through an air gap.

Description

Key with a key body made of non-magnetizable material in which flux guide pieces made of ferromagnetic material are embedded

The invention relates to a key with a key body made of non-magnetizable material, in which flux guide pieces made of ferromagnetic material are embedded at predetermined locations, which form at least one information track and embody the key secret in the form of an at least two-valued code, in the associated lock a reading device is provided which contains at least one magnetic circuit with a permanent magnet and a magnet-sensitive element and the flux guide pieces close this magnetic circuit in accordance with the predetermined code in such a way that the magnetic flux passing through the magnetically sensitive element has different values corresponding to the different ones Assumes code values.

Such a key with associated lock is known from this side DE-AS 29 33 -J53. The disadvantage here is that the so-called key secret is easily recognizable from the outside. When coding in accordance with a two-value code, an information point to which a code value is assigned corresponds to a flow guide with a large exit cross section from the key body, while an information point to which the other code value is assigned also has a flow guide small outlet cross section is embodied. This is true even in the case of mechanically coded, for example serrated, keys Key secret can be seen without further ado and can be easily removed by producing an impression, but this is highly undesirable for reasons of counterfeit security.

This deficiency cannot be remedied by subsequently encasing the key body with a magnetically non-conductive material, for example by embedding it in brass or by overmolding with plastic, since - magnetically speaking - this would create air gaps which would ensure reliable functioning of the lock / key system, if not completely impossible.

The invention is therefore based on the object of providing a key of the type specified at the outset, the coding of which cannot be recognized from the outside and cannot be determined with simple test means, without the maximum magnetic transferable through the key body F-flow is reduced.

This object is achieved according to the invention in that the different code values are embodied by flux guide pieces of different magnetic resistance.

This solution has the advantage of being able to obtain a magnetically coded key with little production engineering effort, which does not reveal any differences between the individual information points from the outside, without undesired, namely the ability to be scanned in the reading device by worsening the To have to accept additional air gaps aggravating the signal-to-noise ratio. In addition, even with the use of electrical / magnetic measuring equipment, considerable effort is required to reliably determine the value of the individual information points, since the current state of development has very small distances between the information points and the use of flux

OMPI Conductors according to small cross-section allowed. Finally, the solution proposed here also has the advantage that the key body is initially produced with an oversize and correspondingly large tolerances and, after coding, can be brought to the necessary, more closely tolerated target size by simple milling, since the cross section the flow guide is not changed by this.

According to a first embodiment, the flux guide pieces corresponding to different code values can consist of material of different magnetic permeability. The flux guide pieces then have the same length, e.g. rectangular cross section.

A further embodiment is characterized in that the flux guide pieces corresponding to different code values each consist of at least two sections, which include at least one magnetic air gap between them, the length or total length of which is dimensioned according to the code value to be embodied. The internal air gap (s) thus created, which are expediently filled with a plastic or another non-magnetizable material, determine the magnetic resistance of the flux guide piece in question and thus the value of the magnetic flux which the magnet-sensitive element in the reading device has enforced.

The maximum possible magnetic flux is expediently assigned to one of the code values to be recognized. This can take the form of this code value being embodied by a continuous flow guide.

For certain locking systems, the use of a key with at least two parallel information tracks is appropriate. In order to influence each other's

_ H -

To keep adjacent information points or flow guide pieces belonging to different information tracks as small as possible, it is proposed that these flow guide pieces be offset from each other by half the distance of the flow guide pieces belonging to the same track, and that a continuous shield plate made of ferromagnetic material is arranged between the information tracks is.

As a further solution to the problem, protection is claimed that all flux guide pieces have the same magnetic resistance, that each flux guide piece is assigned a flux guide plate that forms a magnetic shunt, and that each flow guide piece has an extension in its central region transverse to its longitudinal axis has, whose distance to the flux guide plate is dimensioned in accordance with the code value to be embodied. The different coding can then e.g. in such a way that for each code value which is to generate the smallest magnetic flux through the magnet-sensitive element, the extension of the flux guide piece is dimensioned transversely to its longitudinal axis in such a way that a practically air gap-free transition to the flux guide plate forming the shunt is formed , while for the other code values the height of this extension is kept lower, thus creating a magnetic air gap (which is preferably filled with plastic) to the flow guide plate.

A third solution to the stated object, which is claimed independently under protection, is that each flux guide piece is assigned a flux guide plate forming a magnetic shunt, and that each flow guide piece has an extension in its central region transverse to its longitudinal axis, which is at a predetermined distance of the flow guide plate ends, and that this distance from the embodiment of the one code value forms a magnetic air gap and is bridged by a coding bridge to embody the other code value.

The last two solutions mentioned have the same advantages as those mentioned above for the first solution.

In the drawing, a key according to the invention is shown in several exemplary embodiments and details chosen for example. It shows:

1 is a perspective view of the key body of the key with associated reader,

2 shows a longitudinal section through the key body and reading device,

3-6 the individual steps for producing a key according to FIGS. 1 and 2,

7 shows a cross section through the key inserted into the reader at the level of a first information point in a second embodiment,

8 shows a cross section through another information point of the key shown in FIG. 7,

9, a is a side view and a cross section of a third embodiment of the key,

10, 10a a side view and a cross section a fourth embodiment,

11 - 11b cross sections through two different

Information points of the key in a fifth embodiment and

Fig. 12a - 14 cross sections through two different

Units of the key in a sixth Ausführungsfor ^'and top views and sections of two Be¬ was share this key.

The key body 1 shown in perspective in FIG. 1 is provided with a conventional mechanical coding 2 and with a magnetically readable coding which consists of flux guide pieces 3 made of ferromagnetic material which ^• pass through the key body made of non-magnetizable material. Each flow guide forms ^* an information point and thus embodies a very specific code value, i.e. when using a dual code, either the code value log.O or log.l. The successive flow guide pieces, that is to say the entirety of the information points, form an information track, the distances between the individual information points preferably being of the same size.

The lock belonging to this key contains a reading device 4. This includes a permanent magnet 5. a pole piece 6, the end face cross section of which corresponds approximately to the cross section of the flux guide pieces 3, and a magnetic / electrical transducer 7, the magnetically sensitive area 8 also is approximately equal to the cross section of a flux guide piece 3. The electrical λ connections of the converter are designated by 9. The transducer includes a Hall generator or a field plate, ^'and the per se known plant and from ^¬ value generating circuits for this purpose (not shown). When entering

OMPI Ben of the key body 1, the flux guide pieces 3 connect the permanent magnet 5 with the transducer 7 one after the other. The magnetic circuit thus produced is closed via a yoke 10 in order to improve the efficiency.

The individual code values are embodied by flux guide pieces of different magnetic resistance. For this purpose, the flux guide pieces assigned to the different code values consist of materials of different magnetic permeability and accordingly generate different values of the magnetic flux passing through the magnetically sensitive element of the transducer 7. This type of coding means that the code value assigned to the individual information points is not recognizable from the outside and cannot be easily determined even with the aid of measuring means.

A further possibility of designing the flux guide pieces as magnetic resistors, the resistance value of which is not visible from the outside, is shown in FIG. 2, which shows a section through the reading device with the key body 1 inserted up to the third information point. Here it is assumed that the coding is carried out according to a dual code. One code value is embodied in each case by a continuous flow guide 3a, the other code value by a flow guide 3b, which contains a magnetic air gap 1 in the interior of the key body. This continuous flux guide piece thus generates a high magnetic flux in the transducer 7 *. Each interrupted flux guide piece 3b generates a low magnetic flux in the transducer 7, with the high value for example meaning log.l and the low value the meaning log.O. can be.

A possible way of producing the key shown in FIG. 2 is illustrated in FIGS. 3 to 6. Here it is assumed that two comb-like carriers 11, 12

_OMPI_ consist of ferromagnetic material and have a number of comb teeth corresponding to the number of later information points. While the comb teeth of the carrier 11 are all of the same length, the comb teeth of the other carrier 12 have two different lengths, in such a way that, after the carriers 11 and 12 have been joined together with comb teeth pointing towards one another, they touch the end faces at those points at which later Continuous flow guide pieces 3 are provided, while at the locations provided for the flow guide pieces 3b, the air gap 1 remains between the end faces of the comb teeth. The carriers 11 and 12 are connected to one another via fastening tabs 13, for example by gluing. 3a shows a section along the line aa in FIG. 3 _*, that is, a pair of comb teeth with an air gap 1. FIG. 3b shows a section along the line bb in FIG. 3, that is, a pair of comb teeth without an air gap.

4 is embedded in plastic 14, which can be done, for example, by extrusion coating. FIG. 4a shows a section along the line a-a in FIG. 4.

In the next step, the carriers 11 and 12 are removed, e.g. milled away. This results in the body shown in FIG. 5, the side view of which is shown in FIG. 5a, while a section along the line b-b in FIG. 5b and a section along the line c-c in FIG. 5c is shown.

If necessary, the plastic areas containing the fastening tabs 13 are now milled away. In this way, a compact code element 15 according to FIG. 6 is finally obtained, the flux guide pieces 3 with different magnetic resistances corresponding to the coding provided, embedded in plastic 1,

OMPI contains. The code element 15 is inserted into a suitable recess 16 of the key 17 and glued there. If necessary, the two broad sides of the key body with inserted code element 16 can also be milled over in order to obtain completely flat surfaces. The coding is not affected by this since the magnetic resistance of the flux guide pieces 3 no longer changes. It is only by means of suitable measures, for example by producing the key body and the code element 15 with a small oversize, that the thickness of the key body after the milling is: within the permissible tolerance.

Instead of using the code element 15 in a recess 16 of the key ^• sels, the key can in particular if he is wearing no mechanical coding, consist of plastic and in_ iesem case the injection molding process herge¬ provides be, wherein the pre-code element inserted into the mold and is molded around.

Of course, the code element 15 described can also contain flux guide pieces 3, which include air gaps of different sizes, when encoded according to a higher-value code. In this case, the carrier shown in FIG. 3 has 12 comb teeth with several lengths that are different from one another. Instead of starting from carriers 11, 12 with comb prongs of different lengths, carriers can also be used whose comb prongs of equal length face each other after connecting both carriers at a predetermined distance in accordance with the air gap desired for the one code value. A ladder-like coding grid is then inserted between the two carriers, which fills the air gap at the points which are intended to embody the other code value, while at the points where the air gap is to remain, the corresponding areas of the

OMPI

Λ, IPO Coding grid were previously punched out or otherwise removed.

According to a further embodiment shown in ^" FIG. 7 in section, the individual flow guide pieces can also consist of more than two ^" parts, in particular sandwiched together, the individual parts being used for the parallel production of all flow guide pieces in accordance with the number of the provided coding locations are initially connected in the form of comb-like or ladder-like structures according to FIG. 3. The flow guide piece shown in FIG. 7 in its position between the flow guide piece 6 and the transducer 7 (see FIG. 1) and embedded in the key body 1 consists of an inner flow guide core 18 and two outer flow guide covers 19, where ¬ a narrow transverse joint remains between the respective facing surfaces of the flux guide core 18 and flux guide cover 19. All flow guide pieces consist of these parts, which are connected to one another by a plastic extrusion coating 20. The various code values are generated either by the fact that both transverse joints contain a coding web 21 made of a ferromagnetic material or that, according to FIG. 8, the transverse joints are also made of plastic

20 are filled in, i.e. they form magnetic air gaps.

A further code value for coding according to a trivalent code can be obtained in that a coding bridge

21 is used only in one of the two joints, so that the magnetic air gap is only half as large as in the case of FIG. 8. A further code value for coding according to a four-value code can be obtained in an analogous manner by making the two separating joints on both sides of the river core 18 of different widths, whereby three differently sized magnetic air gaps can be generated.

OMPI With a key of the construction shown in FIGS. 2 and 7, the flow guide pieces corresponding to the individual information points can be arranged at a very small distance from one another. In the case of locking systems which require the use of a plurality of parallel information tracks, the problem then arises in particular to keep the talk between the individual tracks as low as possible. This is achieved with embodiments as shown in the side view and in section in FIGS. 9 and 9a or 10 and 10a. In the former case, the flow guide pieces 3 of the information tracks A and B are offset from one another by half the distance of the flow guide pieces belonging to the same information track. In the latter case, the information tracks A and B are additionally separated from one another by a dish plate 22 made of ferromagnetic material.

While in the previously described embodiments the value of the magnetic flux passing through the magnetically sensitive element 8 of the transducer 7 (cf. FIG. 1) was changed by using flux guide pieces of different magnetic resistance without the relevant code value on the key from the outside is recognizable, one can arrive at the same result by generating a magnetic shunt, which according to the. embodying code values is of different sizes. The two figures show the FIGS. 11 to 11b and 12a to 14.

Fig. 11 shows the key body 1 with its recess 16 for receiving the code element 23 in section. The code element 23 comprises a continuous flow guide 25 embedded in plastic 24, which has an extension 2β only in its central area transverse to its longitudinal axis. This extension 26 touches a flux guide plate 27 which extends over the entire width of the key.

O PI The narrow, lateral end face of the flux guide plate 27 comes to lie in the reader outside the area of the transducer 7 occupied by the magnet-sensitive element 8. A discharge web (not shown) can additionally be arranged in the reader opposite this end face.

11a shows the coding element 23 inserted into the key body 1. The magnetic flux entering the flow guide 25 in the direction of the arrow is divided in this embodiment of the information point into the outlet cross section of the flow guide 25 and the end face cross section of the flow guide 27. The magnetically sensitive element therefore only receives a reduced magnetic flux.

11b shows an information point embodying another code value. The flux guide piece 25 has no continuation in the transverse direction here, and is therefore magnetically separated from the flow guide plate 27 _s, with the result that the magnetic flux entering the flow guide piece 25 via one end face emerges again through the other end face. The space between the flow guide piece 25 and the flow guide plate 27 is filled with the plastic 24. As can be readily seen, coding according to a higher-value code is also possible here by means of differently sized magnetic air gaps between the flow guide piece 25 and the flow guide plate 27, specifically by means of flow guide pieces 25 with extensions 26 of different heights.

12a and 12b show a similar embodiment, but here all of the flow guide pieces 25 have the same extension 26 in their central region transversely to their longitudinal axis, although the end face of this extension ends at a predetermined distance from the flow guide plate 27. At the information point shown, this distance is through

_OMPI

bridges a coding web 29 of the coding grid 28 shown in FIG. 14. In contrast, FIG. 12b shows an information point at which this coding web between the extension 26 of the flow guide piece 25 and the flow guide plate 27 is missing. In the area of the side surfaces of the code element, however, the two coding web supports (see FIG. 14) have been preserved ", which not only ensure that the necessary distance between the extension 26 and the flow guide plate 27 is maintained, but also prevent it from happening." It can be recognized which coding webs have been punched out of the coding grid in accordance with the illustration in FIG. 14 in order to generate the relevant code values.

FIG. 13 shows the continuous flow guide plate 27- in plan view and in section. that is used both for the embodiments according to FIGS. 11 to 11b and 12a, 12b.

Instead of punching out individual coding webs 29, the air gap between the extension 26 and the flow guide plate 27 can also be generated by punching out the corresponding points on the flow guide plate 27 to cancel the shunt. The coding grid 28 can then be dispensed with. As in the case of FIG. 12b, the magnetic parts produced by the stamped-out parts are magnetic. Air gaps filled with the plastic 24.

OMPI r WIPO -

Claims

Patent claims:

1. Key with a key body made of non-magnetizable material, in which flux guide pieces made of ferromagnetic material are embedded at predetermined locations, which form at least one information track and embody the key secret in the form of an at least two-valued code, in the associated lock a reading device is provided which contains at least one magnetic circuit with a permanent magnet and a magnet-sensitive element, and the flux guide pieces close this magnetic circuit in accordance with the predetermined code in such a way that the magnetic flux passing through the magnetically sensitive element assumes different values corresponding to the different code values, characterized in that that the different code values are embodied by flux guide pieces (3) of different magnetic resistance.

2. Sehlüssel according to claim 1, characterized in that the different code values corresponding Flußleit¬ pieces (3) consist of materials of different magnetic permeability.

3. Key according to claim 1, characterized in that the different code values corresponding Flußleit¬ pieces (3a, 3b) each from at least two sections, which include between them at least one magnetic air gap (1), its length or de¬ total length is dimensioned according to the code value to be embodied (FIG. 1, FIG. 7).

4. Key according to claim 3, characterized in that one of the code values by a continuous flow guide

O (3a) is embodied (Fig. 2).

5. Key according to claim 1, with at least two parallel information tracks, characterized in that the different information tracks (A, B) are belonging to the flow guide pieces (3) are offset from one another by half the distance of the flow guide pieces belonging to the same track, and that a continuous shield plate (22) made of ferromagnetic material is arranged between the information tracks.

6. Key, in particular according to claim 1, characterized gekenn¬ characterized in that all flux guide pieces (25) have the same magnetic resistance that the flux guide pieces (25) a magnetic shunt forming flux guide

"sheet (27) is assigned, and that each flow guide piece (25) has an extension (26) in its central region transverse to its longitudinal axis, the distance to the flow guide sheet (27) being dimensioned according to the code value to be embodied ( 11, 11a, 11b).

7. Key, in particular according to claim 1, characterized gekenn¬ characterized in that all flux guide pieces (25) have the same magnetic resistance that each flux guide piece (25) is associated with a magnetic shunt forming flux guide plate (27) that each The flow guide piece (25) has an extension (26) in its central region transverse to its longitudinal axis, which ends at a predetermined distance from the flow guide plate (27), and that this distance to the embodiment of the one code value has a magnetic air gap ( 1) and is bridged by a coding web (29) to embody the other code value.

8. Key, according to one of claims 1 to 7, thereby

O PI indicates that all of the flux-conducting parts and if appropriate all Flußleitbleche are embedded in a magnetically non-conductive material (20, 24) combined to form a code element (15, 18, 23) in a recess (16) of the Sö ^{'hlüsselkörpers} (1 ) is included.