GB2072742A

GB2072742A - Locking device

Info

Publication number: GB2072742A
Application number: GB8111141A
Authority: GB
Original assignee: Sachs Systemtechnik GmbH
Current assignee: Sachs Systemtechnik GmbH
Priority date: 1978-06-06
Filing date: 1979-06-05
Publication date: 1981-10-07
Also published as: IT7968216A0; SE7904778L; FR2428129B1; GB2072742B; FR2428129A1; GB2022187B; IT1118758B; GB2022187A; BR7903548A

Abstract

This invention relates to a locking device having a key a handle part 3 on which there are retained several information carrier parts 5 which are displaceable in relation to one another in a predetermined angle pattern and determine the locking code of the key, the device having a reading device 9 for reading off the locking code from the key and comparing the read locking code with a predetermined locking code. In the device information carrier parts are held for angular displacement about a common axis on the handle part, the reading device detecting the presence or absence of information elements in at least one part of the predetermined angle pattern positions. The carrier parts in the form of rings held for angular displacement by axial protuberances extending from said carrier parts into recesses provided in adjacent rings or in the handle part. <IMAGE>

Description

1 GB 2 072 742 A 1

SPECIFICATION

Locking device The invention relates to a locking device having a key on the handle part on which there are retained several information carrier parts which are displaceable in relation to one another in a predetermined angle pattern and determine the locking code of the key, and having a reading device for reading off the locking code from the key and comparing the read locking code with a predetermined locking code.

Such a locking device is known from German Patent Spec. No. 2,138,991. This locking device is a mechanical lock the tumblers of which are released by shift magnets in the lock housing when a magnetic field with predetermined direction is applied by means of the key to the shift magnets. The key cornprises two magnets, arranged side by side in one plane, which, held on detent discs, can be rotated about axes perpendicularly to the direction of magnetic polarisation. By rotation of the detent discs it is possible to alterthe angle position of the directions of polarisation in relation to one another and to code the key. The disadvantages of the known locking device is the disproportionate increase of space requirement of the key if a high number of coding variants is to be possible.

It is an object of the invention to indicate a locking device in which with minimum possible constructional expense and with a relatively small key a very high number of coding variants is rendered possible, while a subsequent alteration of the coding is especially also to be possible.

According to the invention there is provided a locking device having a key on the handle part of which there are held several information carrier parts which are displaceable in relation to one another in a predetermined angle pattern and which determine the locking code of the key, and having a reading device for reading the locking code from the key and comparing the read locking code with a predetermined locking code, wherein the information carrier parts are formed by rings which are arranged on the handle part and carry at least one information element and which each posses on one side thereof in the axial direction at least one axially extending plug-in protruberance, which protruberances serve to locate the rings at angular dispositions in relation to each other and to the handle portion by engagement with recesses provided in adjacent rings or in the handle portion whereby the rings are adapted for angular displacement about a common axis on the handle part, said reading device being capable of detecting the presence or the absence of the information elements in at least one part of the predetermined angle pattern positions.

At least one part of the information carrier parts carries information elements staggered in relation to 120 one another in the angle pattern and arranged preferably atthe same radial distance from the common axis, and the reading device also comprises several reading elements, staggered in relation to one another likewise in the angle pattern, for the information elements of at leastthese information carrier parts. In this way to each angle pattern position of each information carrier part there is allocated a different part code, consisting of several bits, of the locking code. The number of the information ele- ments per information carrier part can differ from the number of the reading elements allocated to the information carrier part.

Aform of embodiment has proved especially favourable in which the information carrier parts are displaceable into eight angle pattern positions uniformly distributed over360'and carry four information elements, three information elements being adjacent to one another and an empty pattern position being between the fourth information element and one of the other information elements. In this case the reading device preferably comprises three reading elements, arranged in adjacent angle pattern positions, per information carrier part. In the case of the manner of arrangement of the informa- tion elements as explained above, a different code consisting of three bits is allocated to each of the angle positions of the information carrier parts.

The rings may be carried on a spindle part which can be a screw which is screwed, possibly in a cap- tive manner, into the handle part. Forms of embodiment are also suitable in which which the spindle part axially displaceably penetrates the rings and a base part adjoining the rings, while at the one end of the spindle part in the axial direction an abutment head protrudes and at the other end, in the axial direction, a tommy bar is articulated which in its one position clamps in the rings and the base part between itself and the abutment head and in its other position permits axial play of the rings.

It is an advantage of the above-explained forms of embodiment with information parts arranged coaxially side by side thatthe reading elements of the reading device can be accommodated without problems in a small space even in the case of a relatively large number of reading elements. In a further preferred form of embodiment the information carrier parts are rings which are held, arranged coaxially one within the other, on the handle part and each carry at least one information element on one of their end faces. Such a key may have especially small external dimensions and the housing of the associated reading device can also be fitted very easily on a flat surface, for example a glass surface; likewise it has a very small axial extent.

The rings can be fitted on the handle part with a single screw or the like if they carry on their end face remote from the information element a radially inwardly extending collar which engages behind the coaxially inwardly lying adjacent ring.

For many practical cases it can be advantageous if only one part of the information elements is provided on the angularly displaceable information car- The date of filing shown above is that provisionally accorded to the application in accordance with the provisions of Section 15(4) of the Patents Act 1977 and is subject to ratification or amendment at a later stage of the application proceedings.

2 GB 2 072 742 A 2 rier parts, while the other information elements are connected fixedly and thus invariably with the handle part. The information elements invariably connected with the handle part can be a component of the locking code of the key; they can however also 70 be used to release the functioning of the reading device, for example in that such information elements generate a signal which indicates the complete pushing of the key into the reading device. In the case of magnetic information elements, in order to preveritthe reading element of this information element, which determines the locking position of the key, from being actuated by other information elements already in the insertion of the key, it is preferably provided that this information element is at a greater distance from the axis of the information carrier parts than the information elements provided on the information carrier parts. The information element which determines the locking position is expe- diently arranged in a radial protuberance in the reg- ion of the handle part. The protuberance can engage, when the key is in the locking position, in a recess adapted to it on the reading device and orientate the key in relation to the reading device. On the side of the protuberance remote from the handle part there can be provided an axial stop face which, in combi nation with an oppositely directed stop face of the reading device, orientates the key axially in relation to the reading device.

The information elements can be magnetic infor- 95 mation elements which can be scanned for example by means of Hall generators, magnetically sensitive switches or reed switches. In this case either the information carrier elements can consists corn- pletely of a magnetisable material in which indi- 100 vidual areas or zones are magnetised forthe forma tion of the information elements, or separate per manent magnets can be fitted on the information carrier parts.

If the information carrier parts or the handle part consists of electrically insulating material, alterna tively as information element defined electric con tact surfaces can be provided on the outer surface for reading elements, formed as contacts, of the reading device. Such forms of embodiment are con- 110 structionally simple. The contact surfaces provided on the outer surface can be of such configuration that they constitute earth connection for the indi vidual circuits, which is advantageous especially when used on motor vehicles.

The coding of the key can also be effected by phototechnicai methods. Zones with different optical reflection capacity can be provided on the outer surace of the key. The reflection capacity is detected by photo-electric cells of the reading device which respond to the light of a light source reflected from the outer surface. The light source can also be arranged within the key, if translucent windows through which the light can escape are provided in the key wall at the site of the information elements. 125 In place of a light source arranged in the key, light emitting diodes can be fitted on the outer circumfer ence, the light of which is received by photo-electric cel Is of the reading device. For the current supply of the light sources of the key a battery or the like can be accommodated in the key; however it is also possible for contacts to be provided on the key, through which the key can be connected to the current supply of the reading device.

The locking device according to the invention, when the locking code of the key is in conformity with the predetermined locking code, merely generates a tripping signal which is used to control the actual lock. Therefore the locking device is especially suitable for central locking systems in motor vehicles.

Examples of embodiment of the invention are to be explained in greater detail below with reference to drawings, wherein:- FIGURE 1 shows a diagrammatic representation of a first form of embodiment of a locking device, consisting of a codable key and a reading device, FIGURE 2 shows anotherform of embodiment of a key usable in the locking device according to Figure 1, FIGURE 3 shows a detail of the key according to Figure 2, FIGURE 4 shows a sectional view through the key according to Figure 2 along the line IV-IV, FIGURE 5 shows a cross-section through key and reading device of a second form of embodiment of a locking device, FIGURE 6 shows an end view of the key according to Figure 5, FIGURE 7 shows a diagrammatic cross-section through a third form of embodiment of a locking device.

FIGURES 8 to 10 show diagrammatic illustrations of further forms of embodiment of locking devices.

Figure 1 shows a key 1 having a handle part 3, serving for operation, and a substantially circularcylindrical information carrier 5. The information carrier 5 carries a plurality of magnetic information elements 7 which are arranged in a pattern along the cylinder axis of the information part 5 and also in distribution in an angle pattern on the circumference of the information part 5. The distribution of the magnetic information elements 7 in the pattern determines a binary locking code of the key 1 in which pattern places occupied by information elements 7 correspond by way of exampleto a bit '1 and empty pattern places represent a bit "0".

The locking code of the key 1 can be read by means of a reading device 9. The information carrier 5 of the key 1 is introduced forthis purpose into a cylindrical opening 11, adapted to it, in a housing 13 of the reading device 9. The reading device 9 com prises a plurality of magnetic-field-sensitive reading elements 15 arranged both axially and over the cir- cumference of the opening 11 in the pattern of the information elements 7, which respond to the presence or absence of the information elements 7 in the pattern. The reading elements 15 are connected with a comparator 17 which compares the read locking code of the key 1 with a locking code which is supplied from a coder 19. If the prestated locking code is in conformity with the locking code read from the key 1, the comparator 17 emits at its output 21 a signal which can be used for the release or actuation of the lock or the like, which incidentally is not ill us- b 3 GB 2 072 742 A 3 trated.

The lock can be a central locking installation or an anti theft installation of a motor vehicle. The magnetic information elements 7 can be separate permanent magnets which are inserted into a nonmagnetic body of the key. The key can however also consist of magnetic material which is magnetised by zones at the location of the information elements. The reading elements 15 can for example by Hall probes or reed switches.

From the cylindrical circumference of the information carrier 5 in the region of the end axially facing the handle part 3 a protuberance 23 stands out radially and, when the key 1 is in the locking posi- tion, engages in shape-locking manner in a groove 25 adapted to it on the inner periphery of the opening 11. The protuberance 23 and the groove 25 orientate the information carrier 5 in the circumferential direction in relation to the reading elements 15 of the reading device 9. A shoulder 27 of the protuberance 23 axially facing the free end of the information carrier 5 determines the depth of insertion of the information carrier 5. The shoulder 27 is seated against a counter- shoulder 29 of the groove 25 when the key 1 is in the locking position. On the part of the information carrier 5 which remains outside the housing 13 when the key 1 is in the locking position there is provided, between the information carrier 5 and the handle part 3, a radially outwardly protruding collar 31 which in the locking position abuts on the front of the housing 13. The shoulder 27 and the collar 31 can be so dimensioned that in the locking position either in common or individually they determine the axial position of the key 1 in relation to the reading device 9. On the free end of the information carrier 5 there is 100 fitted a substantially conical detent head 33 with a peripheral channel 35 in which there engages a spring-loaded detent member 37, displaceable radially of the opening 11, of the reading device 9 when the key 1 is in the locking position. The conical 105 outer surface of the detent head 33 forms an entry ramp which deflects the detent member 37 in intro duction of the key 1.

In orderthatthe comparator 17 may be prevented from already beginning reading and comparison in 110 the insertion of the key 1, it has a release input 39, to which an additional magnetic-field-sensitive reading element 41 is connected. The reading element 41 responds to an additional magnetic information element 43 arranged in the protuberance 23 of the information carrier 5, which element 43 is arranged at a greater radial distance from the cylinder axis of the information carrier 5 than the other information elements 7 provided on the circumference of the 5.5 information carrier 5. The radial distance of the information element 43 from the cylinder axis is dimensioned so that the reading element41 while actuated by the information element 43 is not actuated by the information elements 7. The comparator 17 is released only when the key 1 is introduced completely into the locking position. The release of the comparator 17 may take place with time delay, in order to prevent release of the comparator 17 while the key 1 is still in movement.

In order that the key 1 may be adapted with 130 minimum production expense to a maximum poss ible number of different locking codes and thatthe locking code may be altered even subsequently is desired, one part of the information elements is arranged on information carrier parts which are engaged coaxially side by side but displaceably in relation to one another in the angle pattern. The information carrier parts fix the pattern in the axial direction of the information carrier, but permit an adjustment of the locking code by rotation of the individual information carrier parts in relation to one another. Figures 2 to 4 show a key 51 similar to the key 1 in Figure 1, on the handle part 53 of which several rings 55, forming the information carrier parts, are secured coaxially side by side on the handle part 53 by means of a screw 57. A further information carrier part 58 is connected in one piece with the handle part 53 and carries a nose 59, which in function and constrcution is comparable with the protuberance 23 of the key 1 according to Figure 1. The information carrier parts 55 and 58 carry magnetic information elements 61 which can be read by a reading device of the kind explained with reference to Figure 1. An information element which trips the reading device can likewise be provided in the nose 59.

The adjustable information carrier parts 55 carry pins 63 on their one end face, in the axial direction, and plug-in openings 65 adapted to the pins, in which the pins 63 of the adjacent information carrier element 55 in each case engage, on their axially opposite side. The openings 65 and pins 63 are arranged in the angle pattern of the reading elements of the reading device. In the example of embodiment according to Figures 2 to 4 the angle pattern positions are staggered by 90' in relation to one another so that, as shown by Figure 4, there are four openings 65. The number of pins 63 might be smaller.

In orderthatthe information carrier elements 55 may be adjusted in relation to one anotherthe screw 57 is slackened so far that the pins 63 may emerge from the openings 65. The information carrier parts 55 are then shifted and the screw is tightened afresh.

Since one part of the information carrier parts, as here the information carrier part 58, is firmly connected with the handle part 53, the locking code determined by the key 51 consists of an invariable basic code part and a variable code part. This is especially advantageous in the case of relatively extensive locking installations with a plurality of keys. The magnetic information elements are represented visibly in the Figures. In the actual forms of embodiment they can befitted for example covered by a foil, so that the locking code cannot be read from the exterior. This is especially advantageous in the case of programmable reading devices which can read the locking code of the key for the purpose of programming.

The grip portion of the handle part of the key 71 may be formed as a tommy bar having a cam profile. The can profile is formed so that clamps the head of the screw 57 and thus the information carrier parts in one position of the tommy bar and permits an axial movement play of the information carrier parts 4 when it is rotated transversely of the axial direction of the screw 57.

Figures 5 and 6 show another form of embodiment of a key 91 in which, in contrast to the aboveexplained forms of embodiment, annular information carrier parts 93,95 are fitted on a handle part 97 not coaxially side by side as in the above-explained forms of embodiment but coaxially one within the other. In contrast to the above-explained forms of embodiment the key 91 is relatively flat. Its information elements 99, which again can be magnetic information elements, are provided in one plate on the end face axially remote from the handle part 97 on the information carriers 93,95. The information elements 99 are arranged in a predetermined angle pattern which is in conformity with the angle pattern and manner of operation of the reading device 103. The function and manner of operation of the reading device 103 correspond to those of the reading device 9 according to Figure 1. The reading device 103 can be of especially flat formation, so that it can be fitted especially on flat surfaces. Provided that the reading elements 101 are sufficiently sensitive, they do not have to extend through a front plate 105, but can also be fitted on the back of the front plate 105, so that the reading device can be fitted, if desired, in covered manner equally on already existing surfaces, for example glass panes. Noses 107 are fitted on the front of the front plate 105 forthe orientation of the key 91.

On the inner circumference the information carrier parts carry inwardly protruding annular shoulders 109 and 111 which in each case engage behind the coaxially inserted part. Into the innermost informa- tion carrier part 95 an insert 113 is inserted which is secured on the handle part 97 by means of a central screw 115. The screw 115, through the insert 113 and the annular shoulders 109, 111, holds the information carrier parts 93 and 95 on the handle part 97.

From the information carrier parts 93, 95 there protrude axially pins 117 engaging in associated openings 119 of the handle part 97. The pins 117 and 119 are arranged in the angle pattern of the information elements 99, so that the information carrier parts 93, 95 can be rotated in relation to one another, after slackening of the screw 115, for the setting of the locking code of the key.

Each of the information carrier parts of the forms of embodiment as explained above can comprise several information elements, and in the reading device several reading elements can be allocated to each of the information carrier parts. The information elements of the individual information carrier parts and the reading elements are preferably staggered in relation to one another in the angle pattern so that at each angle position of the information car rier parts a different locking code contribution of the information carrier part results.

Figure 7 shows a preferred division for a key the information carrier parts 121 of which can be rotated 125 in relation to one another through eight in each case equally spaced angle steps. Each information carrier part comprises four information elements 123, of which three information elements 123 are arranged in immediately adjacent angle pattern positions, 130 GB 2 072 742 A 4 while between the fourth information element 123 and the three immediately adjacent elements one angle pattern position (125 in Figure 7) remains free. To each of the information carrier parts 121 there are allocated in the reading device (not illustrated further) three reading elements 127 arranged in immediately adjacent angle pattern positions. The three reading elements 127 produce a different bit pattern in each of the eight possible angle positions of the associated information carrier part 121.

The information carrier part 121 is illustrated as being octagonal in Figure 7. A possibly present introduction channel of the reading device can have a corresponding form. The principle of Figure 7 can also be used in the case of round information carrier pa rts.

In the forms of embodiment as explained above, magnetic information elements are provided on the keys and are read off by magnetic-fieldsensitive reading elements of the reading device. As already mentioned, the magnetic information elements can be formed as permanent magnets separately inserted into the key body. However the key body can consist at least partially of magnetic material which is magnetised by zones at the positions of the information elements. The above-explained principles, which permit the most versatile possible and even subsequent coding of the keys, can also be used with other forms of embodiment of the infor- mation elements and associated reading elements. Figure 8 shows a key 131 the mutually angularly displaceable information carrier parts of which cornprise surface regions 135 the optical reflection capacity of which differs from the reflection capacity of the remaining circumferential surface of the information carrier parts 133. The reading device comprises light-sensitive reading elements, for example photo-electric cells 137, which receive the light emitted by a light source 139 and reflected from the sur- face of the information carrier parts 133. The identity of the reflected light is dependent upon whether it is reflected by one of the surface regions 135 or the other surface of the information carrier parts. The surface regions 135 form the information elements which determine the locking code. In Figure 8 the light source 139 is allocated to one single photoelectric cell 137. Howeverthe light source 139 can also deliver light for several or even all photo-electric cells of the reading device.

Figure 9 shows another opto-electric coding of the keys. While in the form of embodiment according to Figure 8 the light source is arranged outside the key and the photo-electric cells receive the reflected light of this light source, Figure 9 shows a key 141 the mutually angularly displaceable information carrier parts 143 of which are hollow and contain a light source 145 in their interior. Windows 147 are provided in the wall of the information carrier parts 143 to form the information elements, through which windows the light of the light sources emerges. The reading device again comprises light-receivers, for example photo-electric cells 149, which are illuminated in accordance with the locking code of the key 141. The light source 145 is connected with contact faces 151 through which the light source is supplied 0 GB 2 072 742 A 5 with current from the current source of the reading device. Alternatively a battery or the like can be arranged in the key. In the form of embodiment according to Figure 9 a separate light source is allo cated to each of the information carrier parts 143. 70 Howeverthe light source can also be used forthe illumination of the windows of several or even all information carrier parts. The light source can be a photo-diode which is inserted into the wall of the information carrier part. The information carrier part 75 does not here need to be of hollow formation.

Figure 10 shows a key 161 the angularly displace able information carrier parts 163 of which consists of electrically insulating material. On the circumfer ence of the information carrier parts 163 there are fitted electrically conductive contact faces 165 as information element which, as indicated, by a chain line 167, are connected with a contact face 169. The reading device comprises as reading elements con tacts 171 which rest on the information carrier parts 163 or the contact faces 165 when the key 161 is in the locking position. The contact face 169 is con tacted by a contact 173 of the reading device to which a predetermined voltage potential is fed.

According to whether the contacts 171 restonthe contact faces 165 or not, they conduct the potential of the contact 173 or a potential differing therefrom.

Other circuit arrangements of the contact faces 165 are conceivable. Likewise two contacts of the read ing device can abut on each contact face 165. The potential applied to the contact 173 is preferably earth potential so that keys according to Figure 10 can be used for preference in motor vehicles.

Claims

1. A locking device having a key on the handle part of which there are held several information car rier parts which are displaceable in relation to one another in a predetermined angle pattern and which determine the locking code of the key, and having a reading device for reading the locking code from the key and comparing the read locking code with a pre determined locking code, wherein the information carrier parts are formed by rings which are arranged on the handle part and carry at least one information element and which each possess on one side thereof in the axial direction at least one axially extending plug-in protuberance, which protuberances serve to locate the rings at angular dispositions in relation to each other and to the handle portion by engagement with recesses provided in adjacent rings or in the handle portion, whereby the rings are adapted for angular displacement about a common axis on the handle part, said reading device being capable of detecting the presence or the absence of the infor mation elements in at least one part of the pre- 120 determined angle pattern positions.

2. A locking device as claimed in claim 1, wherein at least one part of the information carrier parts car ries several information elements arranged at equal radial distance from the common axis and staggered in relation to one another in the angle pattern, said reading device comprises several reading elements, likewise staggered in relation to one another in the angle pattern, for the information elements of at least these information carrier parts.

3. A locking device as claimed in claim 2, wherein the number of the information elements per information carrier part differs from the number of associated reading elements.

4. A locking device as claimed in claim 1, 2 or3, wherein the rings are seated axially side-by-side on a spindle part held on the handle part and carrying on the circumference thereof the information element, said protuberance extending from one axial face of said rings which have on their other faces the recesses arranged angularly displaced in a symmetrical pattern.

5. A locking device as claimed in claim 3, wherein the information carrier parts are displaceable into eight angle pattern positions distributed uniformly over 360'and carry four information elements, in thatthree information elements are adjacent to one another and there is an empty pattern position between the fourth information element and one of the other information elements, and the reading device comprises three reading elements, arranged in adjacent angle pattern positions, per information carrier part.

6. A locking device as claimed in any one of so claims 1 to 5, wherein the spindle part is a screw which can be screwed into the handle part.

7. A locking device as claimed in anyone of claims 1 to 6, wherein the spindle part axially displaceably penetrates the rings and a base part of the handle part adjoining the rings, and at the one end, in the axial direction, of the spindle part an abutment head protrubes and atthe other end, in the axial direction, a clamping tommy bar is articulated which in its one position clamps the rings and the base part between itself and the abutment head, and in its other position permits an axial play of the rings.

8. A locking device as claimed in claim 1, wherein the information carrier parts are rings which are held coaxially arranged one within the other on the handle part and each carry at least one information element on one of their axial end faces.

9. A locking device as claimed in claim 8 wherein the protuberances extending axially from the axial end faces of the rings remote from the information elements engage the recesses provided in the handle part, said recesses being arranged in an angle pattern.

10. A locking device as claimed in claim 7 or8, wherein the rings carry on their end face remote from the information element a radially inwardly extending collar which engages behind the coaxially inwardly lying adjacent ring.

11. A locking device as claimed in anyone of claims 1 to 10, wherein in addition to the information elements of the angularly displaceable information carrier parts on the handle part at least one information element is firmly connected with the handle part.

12. A locking device as calimed in claim 11, wherein the additional information elements are fitted in the pattern of the information elements of the information carrier part.

13. A locking device as claimed in claim 11, wherein the additional information elements are arranged between the information carrier parts and 6 operating parts of the handle part.

14. A locking device as claimed in claim 12, wherein the reading element of one of the additional information elements releases the reading device for the reading and/or comparison of the other information.

15. A locking device as claimed in claim 14, wherein the information elements are formed as magnetic information elements and at least one of the additional information elements is at a greater distance from the axis of the information carrier parts than the information elements of the information carrier parts.

16. A locking device as claimed in claim 15, wherein the additional information element arranged at greater distance is arranged in a radial protuberance in the region of the handle part.

17. A locking device as claimed in any one of claims 1 to 16, wherein the information carrier parts have circular cross section and on the handle part or on at least one of the information carrier parts there is provided a protuberance protruding radially of the axis of the information carrier parts beyond the outer edges of the information carrier parts, which protuberance fits into an associated recess on the reading device.

18. A locking device as claimed in claim 17, wherein the proturberance carries a magnetic information element at its position situated most remote from the axis.

19. A locking device as claimed in claim 17, wherein the protuberance has on the side remote from the handle part an axial stop face with which there is associated an oppositely directed stop face of the reading device.

20. A locking docking device as claimed in claim 17, wherein the key comprises between the proturberance and the handle part an outwardly protruding shoulder pointing away from the handle part, with which shoulderthere is associated an oppositely directed stop face of the reading device.

21. A locking device as claimed in any one of the preceding claims, wherein the information carrier parts and/or the handle part consist of a zonally magnetic permanent magnetic material.

22. A locking device as claimed in any one of claims 1 to 20, wherein permanent magnets are inserted singly into the information carrier parts and/or the handle part.

23. A locking device as claimed in anyone of the preceding claims, wherein the information carrier parts and/orthe handle part consist of electrically insulating material and carry on their outer surface, as information element, defined electric contact faces for reading elements formed as contacts.

24. A locking device as claimed in claim 1, wherein the information carrier parts and/or the handle part comprise, for the formation of information elements, external surface zones the optical reflection capacity of which differs from the reflection capacity of the remainder of the outer surface, and this reading device comprises at least one light source illuminating the outer surface and reading elements formed as photo-electric cells.

25. A locking device as claimed in claim 1, GB 2 072 742 A 6 wherein the information elements of the information carrier parts and/or of the handle part are active light emitters and the reading elements of the reading device are formed as photo-electric cells.

26. A locking device as claimed in claim 25, wherein the key comprises at least one light one light source accommodated in a cavity, and a translucent window in the wall of the cavity atthe location of each of the information elements.

27. A locking device as claimed in claim 25, wherein a light-emitting diode is arranged at the location of each of the information elements.

28. A locking device as claimed in claim 1 and substantially as hereinbefore described with refer- ence to any one of the embodiments shown in the accompanying drawings.

Printed for Her Majesty's Stationery Office by The T weeddale PressltdBerwick-upon-Tweed, 1981. Published at the Patent Office, 25 Southampton Bui1diigs, London, WC2A lAY, Ifrorn which copies rnaV be obtained.

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