Electronic locking device

FIELD OF THE INVENTION

The present invention relates to the field of electromechanical or electronic keys and locks for preventing access to a given place or for preventing a determined apparatus from being put into operation, for example a rack or cabinet of electronics.

PRIOR ART

Over the last few years, locks have been developed that associate mechanical encoding, e.g. implemented in the form of notches, with electronic encoding transmitted between the key and the lock. Patent application EP 0 277 432 shows an example of such an electromechanical lock in which the key comprises not only mechanical encoding for unlocking the lock, but also an electronic circuit which acts, on insertion of the key, to transmit a preprogrammed identity code to the lock. The key is powered from the lock which is itself powered from an external source. Similarly, application FR 2 561 292 discloses an electronic key capable of being used with an electromechanical lock and having both notches for mechanical encoding and an electronic microprocessor circuit powered by electricity taken from a rechargeable battery placed directly in the key.

Nevertheless, both the above locks suffer from a major defect that results from the fact that the type of cylinder used is particularly complex to make and is thus very expensive. In that type of lock, it is the difficulty of copying the mechanical profile of the cylinder which guarantees maximum security and not the additional electronic encoding. As a result, if the key is lost, then it is necessary to replace the cylinder whether or not it is associated with an electronic circuit.

Also, in application EP 0 388 997, its Proprietor proposes a lock which is an entirely electronic lock and which is unlocked solely by a match between the identity codes of the key and of the lock.

That type of electronically-locked lock nevertheless also suffers from certain drawbacks, in particular with respect to its power supply which is generally obtained from an external source or from a rechargeable battery. Unfortunately, such an external source is not always available, and using a battery placed inside the lock, in the key, or in both of them simultaneously, suffers from serious difficulties of recharging and of reliability in operation.

OBJECT AND DEFINITION OF THE INVENTION

An of the present invention is to mitigate the above-specified drawbacks by proposing an electronic lock and key assembly that is entirely self-contained, requiring no independent power supply, whether external or in the form of one or more batteries that can be recharged by means of an external device. Another object of the invention is to provide a lock cylinder and a key each of which is relatively simple to make and low in cost, and which guarantee that the system is completely secure.

These objects are achieved by an electronic key comprising, mounted in a key body, a key shank for insertion into a corresponding housing of a lock cylinder for the purpose of unlocking it, the cylinder having a stator portion and a rotor portion secured to a tongue, and including first mechanical means and first electronic means, and the key including second mechanical means and second electronic means for co-operating with the corresponding first means of the cylinder when the key is fully inserted in the cylinder and for causing the lock to be unlocked when an identity code of the key and a corresponding code of the lock match, the key being characterized in that the electronic means of the key are powered from self-contained power generator means actuated merely by displacing the key shank in the body of the key.

By means of this particular structure, the electronic means of the key for interchanging and verifying identity codes and possibly also for controlling unlocking of the lock can be powered by a single module actuated solely by moving the shank of the key and independently of any external power supply device.

In a preferred embodiment, the said power generator means is connected via a power link to a rectifier and storage means which generates a DC power supply voltage from AC signals delivered by the power generator means, said rectifier and storage means itself being connected to processor means which, via a communications link connecting it to the power generator means, serves to interchange the data required for unlocking the cylinder.

Advantageously, the power link and the communications link constitute a single link at the power generator means, and the second electronic means then include multiplexer/demultiplexer means for connecting the power generator means both to the rectifier and storage means and to the processor means.

Preferably, the second electronic means further include communications interface means disposed between the processor means and the power generator means for matching and filtering the signals delivered at the output of the processor means.

In a first preferred variant, the rectifier and storage means is also connected to the power generator means so as also to power the cylinder of the lock when the key is inserted in the lock. In this way, the cylinder can operate in self-contained manner without relying on any internal power supply (battery or mains, for example).

In a first example, the power generator means include at least one piezoelectric element designed to generate electric charge from successive bending movements generated by the displacement of the shank of the key. Advantageously, the piezoelectric element is constituted by a single piezoelectric plate embedded at one of its two ends in the body of the key and which can either have a serrated profile designed to co-operate with at least one contact tip of a piezoelectric element of the cylinder while the key is being inserted into the cylinder, or else the end of said piezoelectric plate that is left free has a contact tip and is designed to co-operate with a serrated profile of the key shank during extraction/retraction of the shank out from or into the body of the key.

The key shank may also have an additional piezoelectric element connected to the processor means and designed to interchange data between the key and the cylinder of the lock after the key shank has been inserted in the cylinder.

The key shank may further include at least one contact area connected to the processor means and designed to interchange data between the key and the cylinder of the lock after the key shank has been inserted in the cylinder. Advantageously, the contact area is also connected to the output of the rectifier and storage means to enable the cylinder to be powered from the lock after the key shank has been inserted in the cylinder.

In a particular embodiment of the key, said key shank may be of cruciform shape.

In a second preferred variant, the power generator means comprise firstly a magnetized shank constituting a magnetic core, and secondly a plurality of coils connected in a ring, and separated by walls of material having high magnetic permeability, and contained in a body which is itself made of a material having high magnetic permeability and forming a sheath for said magnetized shank, an ejection system, e.g. using a spring being provided to extract/retract said shank from and into its sheath.

Advantageously, the magnetized shank has a plurality of bipolar annular magnets that are regularly separated by walls of material having high magnetic permeability, the distances between said walls being determined in such a manner as to correspond exactly firstly with the differences between the corresponding walls of the sheath-forming body of the key, and secondly with the walls of said tube of the cylinder.

The bipolar annular magnets have polarities that are determined in such a manner that two adjacent magnets repel each other, with the north/south axes of the magnets being parallel to the longitudinal axis of the shank.

The magnetized shank further includes a wall of material having high magnetic permeability, such as soft iron, and for the purpose, on said wall coming into contact with an external magnetic separation wall of the sheath-forming body of the key, of closing the magnetic circuit when the key is fully inserted into the cylinder.

Preferably, there are four of said coils, with the winding directions of two adjacent coils of said four coils being opposite to the winding direction of the other two coils. The four coils have two distinct electrical contact terminals via which there are respectively provided the power link for powering the second electronic means of the key, and the communications link for interchanging data with the cylinder of the lock.

The invention also provides a lock designed to receive the above-described electronic key and in which the cylinder has at least one power generator means that is actuated during or at the end of insertion of the key so as to power the first electronic means of the cylinder.

In a first advantageous variant, the power generator means also serve to provide coupling between the key and the cylinder of the lock, to enable data, in particular identity codes, to be interchanged between the cylinder and the key after the shank of the key has been inserted in the cylinder.

In a second advantageous variant, the power generator means also makes it possible to cause an element for blocking the tongue to be displaced so as to unlock the lock.

The power generator means is connected via a power link to rectifier and storage means which generate a DC power supply voltage from alternating signals delivered by the power generator means, said rectifier and storage means itself being connected to processor means which, via a communications link connecting it to the power generator means, serves to interchange data required for unlocking the cylinder of the lock, said processor means also serving to drive control means which deliver a control pulse to the power generator means via the communications link, said pulse being of determined duration that is sufficient to release the element for blocking the tongue, thereby unlocking the lock.

Preferably, the first electronic means of the cylinder further include switching means enabling the power generator means to be connected via its communications link both to the processor means and to the control means.

In a first preferred variant, the power generator means of the cylinder comprise at least one piezoelectric element having electrical contact terminals with successive bending movements thereof during insertion of the key generating electric charge at the contact terminals thereof.

The piezoelectric element may be constituted by a single piezoelectric plate embedded at one of its two ends in the rotor portion of the cylinder or by a bimorph whose central portion is embedded in the rotor portion of the cylinder. Each free end of the piezoelectric element has at least one contact tip designed to co-operate with the shank of the key and at least one blocking element designed, in a rest position, to prevent any rotation of the tongue relative to the stator portion of the cylinder.

In a second preferred variant, the power generator means of the cylinder is mounted around the housing, at the inlet to the cylinder, and comprises a tube of high magnetic permeability material, such as soft iron, containing a plurality of coils connected in a ring and separated by regularly spaced walls of material having high magnetic permeability, said coils being designed to co-operate firstly with a magnetized shank forming a magnetic core and carried by the key, and secondly with a key-expelling piston suitable for sliding in the housing and provided with said elements for blocking the tongue.

Preferably, there are four of said coils, with the winding direction of two adjacent coils in said four coils being opposite to the winding direction of the other two coils, and the four coils have two distinct electrical contact terminals via which there are provided respectively a power link for powering the first electronic means, and a communications link for interchanging data and for actuating the blocking element.

In an advantageous example, the tongue comprises firstly a cylindrical body and secondly a fin extending radially from said body, the body having an opening for receiving two hollow annular pieces made of a material of high magnetic permeability and placed one against the other while leaving between them an empty disk-shaped space, the inside dimensions of said pieces corresponding to the outside dimensions of the housing, and each inside wall of the annular pieces in contact with said empty space includes a blocking slot designed to receive said blocking element. The fin includes centering means, e.g. formed by a ball-and-spring assembly, designed to cooperate with corresponding means of the stator portion of the cylinder, e.g. with cavities for receiving the balls.

The key-expelling piston has a central core of material having high magnetic permeability, and at each of the two ends of which there is mounted, about a respective axis, said blocking element formed by a slightly magnetized rotary blade, said blocking blade being pivotable to come into one of said locking slots of the tongue when the power generator means is actuated. The central core is covered in a non-magnetic material and terminated at both ends by respective mechanical interface elements designed to co-operate with the mechanical interface means of the key to transmit the rotary couple.

The present invention also relates to a locking system provided with an electronic key and an associated lock.

BRIEF DESCRIPTION OF THE DRAWINGS

Other characteristics and advantages of the present invention appear more clearly from the following description given by way of non-limiting indication, and with reference to the accompanying drawings, in which:

FIG. 1

is a diagrammatic view of an electronic key used in an electronic locking system of the invention;

FIG. 2

is a diagrammatic view of a dual cylinder of a lock used in the electronic locking system of the invention;

FIG. 3

shows a variant embodiment of the electronic means of

FIGS. 1 and 2

;

FIGS. 4 and 5

show two examples of the rectifier and storage means of the means of

FIGS. 1 and 2

;

FIGS. 6

a

to

6

e

and

7

a

to

7

c

show the various signals available in the electronic means respectively of the cylinder and of the key shown in

FIGS. 1 and 2

;

FIG. 8

is a functional diagram of a first example of power generator means for the locking system;

FIG. 9

shows a first embodiment of an electronic key having a piezoelectric module whose shank is in a retracted first position;

FIG. 10

shows a second embodiment of an electronic key having a piezoelectric module whose shank in a second position;

FIG. 11

is a cross-section through an embodiment of the shank of the electronic key;

FIG. 12

shows an embodiment of a lock cylinder suitable for co-operating with the electronic key of

FIG. 10

;

FIG. 13

is a functional diagram of a second example of power generator means for the locking system of the invention;

FIG. 14

is a diagrammatic longitudinal section through a first embodiment of the cylinder of

FIG. 2

;

FIG. 15

is a cross-section view on plane XV—XV of

FIG. 14

;

FIG. 16

is a diagrammatic longitudinal section of a second embodiment of the cylinder of

FIG. 2

;

FIG. 17

is a cross-section view on plane XVII—XVII of

FIG. 16

;

FIG. 18

is a diagrammatic longitudinal section view of another embodiment of the cylinder of

FIG. 2

;

FIGS. 19

a

and

19

b

show an embodiment of the tongue of the cylinder of

FIG. 18

;

FIGS. 20

a

and

20

b

show an embodiment of the key-expelling piston of the cylinder of

FIG. 18

;

FIGS. 21

a

and

21

b

relate to the embodiment of FIG.

18

and show the interaction between the key and the cylinder for two successive positions of the key;

FIG. 22

is a diagram showing key-cylinder interaction after the key has been fully inserted; and

FIG. 23

is a diagram showing key-cylinder interaction when the tongue is released.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

The present invention relates to an electronic key, to an electronic lock, and to the combination of the key and the lock, referred to in the present application as an electronic locking system. In conventional manner, the lock has a cylinder provided with a housing for receiving the key and with mechanical and electronic elements for unlocking the lock when the key is inserted into the housing, and when an identity code of the key matches a corresponding identity code of the lock.

Reference is made initially to

FIG. 1

which is a highly diagrammatic representation of the key

10

conventionally comprising a shank-forming first end of shape and dimensions that fit the housing in the cylinder of a lock whose bolt (not shown) is to be actuated, and a second end constituting the body of the key and forming a head which, on being rotated, serves to actuate a tongue of the cylinder and thus to drive the bolt of the lock (via conventional mechanical lock means, not shown).

The key has a second mechanical interface means

12

for transmitting the rotary couple from the key to the lock and making it possible, once the key has been coupled with the lock, for the bolt to be actuated when conditions for enabling the lock to be opened are complied with (matching identity codes of the key and of the lock, respectively). It also includes first power generator means

14

for operating, in a communications link and in a power link both to convey data between the key and the lock and to power the key and possibly also the cylinder of the lock. First rectification and energy storage means

16

connected to the power generator means (via the power link) are also provided to receive and accumulate energy from said power generator means, e.g. when the key is inserted in the lock. The rectification and energy storage means is connected to first processor means

18

, advantageously having a microprocessor and a memory, which it serves to power, and which in turn manages (in particular by comparing the identity codes of the key and of the lock) and controls transfer of data corresponding to the identity codes. The interchange of this encoded data is optionally performed via first communications interface means

20

(which if necessary matches and filters the signals from the processor means) connected firstly to the processor means

18

and secondly to the power generator means

14

(via the communications link) through which the interchange takes place. When the cylinder has no power supply means, an additional output link from the rectifier and storage means

16

serves to deliver energy stored from the power generator means

14

to power the cylinder.

FIG. 2

is a highly diagrammatic longitudinal section through a first embodiment of a cylinder

30

of symmetrical European profile having two inlets (two cylinders) of outside shape and size analogous to those of conventional mechanical dual cylinder locks, thereby greatly facilitating replacement, and provided with self-contained power generator means specifically adapted to co-operate with a key of the above-specified type, itself provided with its own power generator means. This dual cylinder lock conventionally has an upstream portion

32

, a downstream portion

34

, and an intermediate rotary portion or tongue

36

which can be rotated by the key by means of the mechanical second interface means

12

when the key is inserted into either of the two housings

38

of the two cylinders, and providing the identity codes match. The cylinder has moving shutter means

40

constituting a key-expelling piston for preventing any external action being taken on the tongue

36

and for cooperating with the mechanical second interface means

12

to rotate the tongue. It also has second and third power generator means

42

,

44

that are identical and that are associated respectively with the upstream portion

32

and with the downstream portion

34

of the dual cylinder lock and which serve not only to supply power to the lock (via a power link) but also firstly to perform a communications function between the key and the lock (via a communications link), and secondly a function of unlocking the lock (by releasing its tongue) via the communications link. Like for the key, each of the two power generator means is connected via the power link to a respective second (or a third) rectifier and energy storage means

46

(or

48

) for rectifying and accumulating energy generated by the means

42

,

44

when a key is inserted in the lock. The second and third rectifier and energy storage means are connected to power respective second and third processor means

50

and

52

, each advantageously constituted by a microprocessor and memory, and each of which manages and controls the transfer of data corresponding to the identity codes of the key and of the lock. This transfer of encoded data (between the key and the lock) is optionally performed (when it is necessary for the processor means to perform signal matching and filtering) via respective second and third communications interface means

54

and

56

connected firstly to the second or third power generator means (via its communications link) and secondly to the second or third processor means. Finally, first and second control means

58

and

60

(e.g. of the transistor switch type) are provided for controlling release of the lock under instructions respectively from the second and third processor means

50

and

52

, by causing the energy accumulated in the second or third rectifier and energy storage means

46

or

48

to be discharged as a pulse over the communications link of the third or second power generator means

44

or

42

. Preferably, when the cylinder is of the dual cylinder structure as shown, the energy accumulated in the rectifier and storage means of a determined portion of the cylinder (e.g. the upstream portion) is discharged into the power generator means of the other portion of the cylinder (in this case the downstream portion), and vice versa. Since the energy is discharged via the communications link, it is preferable to provide switching means

62

,

64

(e.g. a discriminating filter) controlled by the processor means

50

,

52

for directing the communications output from the power generator means either to the communications interface means

54

,

56

or else to the control means

58

,

60

.

When the communications link and the power link comprise a single link in the key as in the lock, i.e. when data is transmitted over the power supply line, it is necessary also to provide multiplexer/demultiplexer means

66

(

FIG. 3

) to direct said single link either to the rectifier and energy storage means

16

;

46

,

48

or else to the communications interface means

20

;

54

,

56

, and vice versa (possibly via the switch means

62

,

64

). Naturally, when the lock is powered from the key, the multiplexer/demultiplexer means

66

is also connected to the output of the rectifier and storage means to make such return power supply possible.

It can be observed that although second and third processor means are described, there is clearly nothing to prevent making use of single processor means only (see for example the circuit

51

in

FIG. 12

) which can indeed be preferable for reasons of minimizing bulk. Similarly, although the present invention is illustrated essentially by means of a dual cylinder structure, it is entirely possible to envisage implementing the invention with a single cylinder type structure having a knob of international profile, for example, or any other analogous mechanical structure. Similarly, it may also be observed that the disposition within the cylinder body of the various electronic means specified above is not exclusive and it is entirely possible, and even preferable, to envisage grouping all of the electronic means together in the tongue (as shown for example in FIGS.

12

and

14

). The same applies to the disposition of the power generator means which may be different (see in particular

FIGS. 16 and 17

for a disposition which instead of being upstream/downstream is on one side and on the other of the longitudinal axis of the cylinder).

FIGS. 4 and 5

show two embodiments of the rectifier and energy storage means

16

;

46

,

48

associated with each power generator means of the key or of the cylinder

14

;

42

,

44

. In

FIG. 4

, it can be seen that the means

16

;

46

,

48

can be constituted merely by a diode bridge

200

followed by a filter and energy storage element such as a capacitor

202

. On an input

210

, the bridge receives an AC voltage from the power generator means

14

;

42

,

44

, and on an output

212

it generates a DC output voltage intended firstly, for example, for releasing the tongue (in the case of the power generator means

42

,

44

of the cylinder) or for powering the cylinder from the key (in the case of the corresponding means

14

of the key) and, secondly, via a voltage divider

204

, for powering the processor means

18

;

50

,

52

. Another possible solution for implementing the rectifier and storage means is to make use of a diode voltage multiplier

220

(FIG.

5

). The voltage multiplier conventionally comprises a plurality of rectifier and voltage raising stages, e.g. six stages

222

to

232

, each constituted by a diode and a capacitor. With this structure, the processor means

18

;

50

,

52

is powered directly from the output

234

of one of the stages of the multiplier, e.g. the second stage

224

, which has a voltage that corresponds to the desired power supply voltage for the processor means, with the other, intermediate outputs of the multiplier serving to deliver various DC voltages, e.g. in the key, for powering the cylinder (by analogy with FIG.

1

).

FIGS. 6 and 7

are histograms showing the electrical signals available at the outputs of the various electronic means described above for the particular case of the power for the key and for the lock being generated by the key being inserted into the cylinder of the lock.

FIG. 6

a

shows the output current from the power generator means

42

,

44

of the lock, after the key

10

has been inserted into the cylinder

30

.

FIG. 6

b

shows the current output by the rectifier and storage means

46

,

48

(the dashed line curve showing the charge voltage).

FIG. 6

c

shows the interchange of codes between the lock and the key at the output from the communications interface means

54

,

56

.

FIG. 6

d

shows the control signal generated at the output of the processor means

50

,

52

for enabling the tongue to be released by discharging the energy which was accumulated in the storage means

46

,

48

on insertion of the key into the coupling means

42

,

44

(see in

FIG. 6

e

the output signal from the control means

58

,

60

). Similarly,

FIG. 7

a

shows the current output by the power generator means

14

of the key.

FIG. 7

b

shows the current output by the rectifier and storage means

16

(the dashed line curve showing the charge voltage), and

FIG. 7

c

shows codes being interchanged between the lock and the key at the output from the communications interface means

20

.

On examining these histograms, it can be seen that the operations performed by the various electronic means take place in three successive stages. Firstly AC is generated in parallel in the lock and in the key, which AC is rectified to deliver power supply voltages to the respective processor means of the lock and of the key (first stage), which means are then activated. They can then proceed to interchange identity codes and compare them (second stage). After this interchange, and assuming that the codes match, the lock can be opened by discharging the energy accumulated in the storage means so as to release the tongue, and thus the cylinder, as explained in greater detail below.

It will be observed that when the lock is powered from the key, the structure of the electronic means of the cylinder can be simplified by omitting the rectifier means

46

,

48

, with the output voltage from the power generator means of the lock being delivered directly in the form of a DC voltage (but it is also possible to add a DC/AC converter in the key without altering the structure of the cylinder).

FIG. 8

shows in highly diagrammatic and functional manner a first embodiment of the power generator means of the lock and of the key in the form of piezoelectric elements.

The power generator means of the lock

42

or

44

is constituted essentially by a piezoelectric element such as a piezoelectric plate

68

provided with electrical contacts

68

a

to provide the communications and power links, the plate being embedded at one of its two ends in the body of the cylinder

30

, and having at its free, other end a contact tip

68

b

that is subjected to pivoting and that is designed to co-operate with a particular serrated profile

70

b

of the key.

The power generator means

14

of the key likewise comprise a piezoelectric plate

70

provided with electrical contacts

70

a

, embedded at one of its ends in the body of the key

10

, and supporting the serrated profile

70

b

, with its other end being free to move back and forth under pressure from the contact tip

68

a.

Piezoelectric plates are components known to the person skilled in the art and therefore do not need describing in detail. It is merely observed that the plates which are multilayer composite structures of piezoactive ceramic provide bending movement of sufficient amplitude to make self-contained power generation possible (i.e. without any need for an additional power supply source such as a rechargeable battery, even though using such an external source is naturally not to be excluded, particularly when the key has sophisticated programming functions), and naturally capable of powering the processor means of the lock and also of the key (which means require little energy), but also and above all capable of powering the control means that enable the lock to be released. A plate of small dimensions (40 mm×10 mm×1 mm) can bend through an amplitude of ±0.5 mm under the effect of stress and thus allow a non-negligible quantity of energy to be accumulated. Under such circumstances, it will readily be understood that subjecting the plate to a plurality of deformations (in practice the number of deformations can lie in the range 10 to 40) makes it possible to obtain sufficient energy to power all of the components of the key and to release the lock without there being any need for an additional power supply. The piezoelectric energy constituted by the alternating and cyclic flow of charge that results from such successive deformations and that is available at the electrical contact terminals of the key and of the lock

68

a

,

70

a

, is then transferred and accumulated in the respective rectifier and storage means

16

;

46

,

48

to enable the system of the invention to be powered. Conversely, given the reversibility of such a piezoelectric plate, discharging sufficient energy across its contact terminals

68

a

,

70

a

will cause it to move, and that can be used for actuating release of the tongue.

However, such piezoelectric plates can also be used as communications means for interchanging data between the lock and the key. When the key

10

is fully inserted in the cylinder

30

, the piezoelectric plate

70

of the key and the piezoelectric plate

68

of the lock are both subjected to bending and are therefore mechanically coupled together. Such a structure then forms a coupled oscillator which has its own resonant frequency that can be used as a communications carrier frequency. This frequency is stored, e.g. in the processor means of the lock, which means can give the signal for starting data interchange in the form of a short period of excitation of said oscillator at said frequency, and the key can then give this reference the logic value 0. Logic value 1 can be communicated from the key to the lock or vice versa under such circumstances in conventional manner merely by changing the phase or the frequency of the reference signal, and naturally by doing so for a length of time that is sufficient to enable the change to be detected. The communications bandwidth corresponds to that of the mechanical coupling.

A preferred embodiment of an electronic key of the invention is shown in FIG.

9

. This key is in the form of a box (the key body

80

) containing a shank

82

that can be extracted by any known means, whether manual (e.g. a serrated button) or automatic, and designed to be inserted in the housing

38

of the lock. The shank shown in a retracted position has an external serrated profile

82

a

for co-operating at least with one contact tip

84

a

of at least one piezoelectric element (the plate

84

) having one end embedded in the box

80

and having its opposite end free and movable under displacement of the contact tip

84

a

. In the example shown, the extractable shank

82

has a symmetrical serrated profile on two opposite faces and there are four piezoelectric elements, with each contact tip

84

serving to actuate two elements simultaneously. Naturally, this configuration is given purely by way of illustration and depends essentially on the amount of electrical energy that needs to be produced. By way of example,

FIG. 11

shows a shank

86

of cruciform section that excites four piezoelectric elements

88

a

,

88

b

,

88

c

, and

88

d

. Naturally, the key also includes a circuit for converting the electric charge generated by the piezoelectric elements (the rectifier and storage circuit

16

may include a capacitor of large capacitance, or a storage or rechargeable battery) and a microcontroller or microprocessor type controlling integrated circuit

18

that is powered directly by the circuit

16

to which it is connected. The processor circuit

18

, which may include the communications interface circuit

20

, is connected to the piezoelectric element

70

mounted on the shank

82

and designed to cooperate with a corresponding piezoelectric element of the lock (element referenced

68

in

FIG. 8

) for the purpose of interchanging identity codes.

FIG. 10

shows a variant embodiment of the key of

FIG. 9

in which the shank

82

is shown in its deployed or “second” position. In this variant, the communications link for interchanging codes takes place via at least one contact area

82

b

of the shank

82

(advantageously one area per face so that the key can be inserted either way round) which area is also used for transferring the power required for the lock and taken from the output of the rectifier and storage circuit

16

(such a contact area is also present in the variant of FIG.

11

). The other elements of the key are identical to those mentioned above with reference to FIG.

9

and are not described again.

It is important to observe that the various embodiments shown are not limiting in any way and that, for example, it is possible for the shank of the key

82

to have not only at least one contact area

82

b

for powering the lock from the key, but also a piezoelectric element for interchanging data. In these embodiments, it will also be observed that power generation in the key now comes from the shank being extracted from its box (or being retracted into the box), whether manually or automatically (as opposed to by the shank being inserted into the lock), thereby exciting the piezoelectric element

84

of the key and causing energy to be accumulated in the corresponding storage means

16

. Thereafter this energy is used for powering the processor means

18

,

20

managing communications between the key and the lock, and in a variant for transferring sufficient energy to the lock to enable it to be powered.

FIG. 12

shows in highly diagrammatic manner a lock cylinder intended more particularly for receiving an electronic key of the kind described above with reference to FIG.

10

. In this cylinder configuration, the power generator means

42

,

44

can be no more than contact areas

42

a

and

44

a

designed to co-operate with the contact area

82

c

of the key and via which there passes not only the energy required for powering the lock, but also the data required for checking the identity codes. The electronic processor circuit

51

, which advantageously comprises a microprocessor and a memory, serves to manage these codes and, if they match, to release the control means which in turn release the cylinder.

FIG. 13

shows in highly diagrammatic and functional manner a second embodiment of the power generator means of the lock and of the key in the form of magnetic elements.

In this embodiment, the power generator means of the lock

42

,

44

is constituted merely by a plurality of identical coils, e.g.

90

,

92

,

94

, and

96

conventionally connected in a ring and mounted in a tube of high magnetic permeability, e.g. having a soft iron case

98

, and also serving to provide magnetic separation between the coils, the first two coils

90

and

92

being wound in one direction (represented by crosses) while the two immediately following coils

94

and

96

are wound in the opposite direction (with each of their windings being represented by a dot in a circle). A first electrical contact

100

for providing the power link is taken between a first link point between the first and fourth coils

90

&

96

and a second link point is taken between the second and third coils

92

&

94

; and a second electrical contact

102

is taken to provide the communications link from a third link point between the first and second coils

90

&

92

and from a fourth link point between the third and fourth coils

94

&

96

. The coils

90

,

92

,

94

, and

96

are designed to co-operate with a magnetic core outside the cylinder so as to form a magnetic circuit whose magnetic flux is reversed cyclically, thereby making it possible to induce alternating current at the electrical contacts

100

and

102

. In similar manner to the above-described piezoelectric structure, it can be seen that this magnetic structure is likewise reversible and that causing electricity to flow in the coil by means of the electrical contact terminals will generate magnetic flux that can be used for releasing a tongue-locking element, thereby causing the lock to be released.

The power generator means

14

of the key is identical in structure, in particular with respect to size, having four coils

110

,

112

,

114

, and

116

likewise connected in a ring and mounted in a soft iron case

118

(the body of the key) and similarly having magnetic separator walls between the coils whose winding directions and connections are similar to those described above. First and second electrical contacts

120

and

122

are similarly provided for the power link and the communications link. Nevertheless, the means

14

of the key further include, at one end of the shank

124

of said key, four bipolar annular magnets

130

,

132

,

134

, and

136

placed side by side and separated by washers

138

,

140

,

142

, and

144

of soft iron forming magnetic separation walls, with the polarities of the magnets being chosen so that two adjacent magnets repel each other (the north/south axes of these magnets being parallel to the axis of the shank

124

). The annular magnets are of a size that accurately matches the size of the surrounding cases

98

,

118

so that the separation walls between the magnets coincide exactly with the separation walls between the coils of the cases, thus providing four closed magnetic boxes each containing one magnet and one coil, as it were. The magnets and the washers are mounted on the shank

124

by means of a threaded rod

146

, for example, secured to the shank and on which the magnets and the washers are screwed. Furthermore, an additional soft iron washer

148

is mounted at the other end of the shank

124

at a distance from the nearest washer

144

, which distance is designed so that when the key

10

is fully inserted in the cylinder

30

of the lock (and thus complete magnetic coupling is achieved), said additional washer which also forms a magnetic separation wall, coincides exactly with the outer separation wall of the case

118

of the key so as to close the magnetic circuit completely, thereby preventing any fraudulent electromagnetic action being taken and generating very powerful induced currents. Conventional shank ejection means, symbolized merely by a spring

150

, enable the magnets of the sheath-forming piece of the key in which they are initially enclosed (in their rest position) to be released before they are inserted into the cylinder (in the working position) level with the soft iron case of the lock

98

(and its coils

90

to

96

) with which they constitute a magnetic circuit.

Once closed in this way, the magnetic circuit constituted by the coils of the key, the coils of the cylinder, and the magnetized shank of the key forms a lossless coupled transformer having its own resonant frequency. Codes can then be interchanged by inductive coupling at high frequency without making use of any direct electrical contact, by using conventional phase or frequency modulation.

FIGS. 14 and 15

show an embodiment of a dual cylinder

30

designed to receive an electronic key

10

provided with piezoelectric power generator means. The cylinder conventionally comprises a rotor element

300

secured to the tongue

36

and surrounded by a stator element

302

. The housings

38

for receiving the key

10

and in which the key-expelling piston

34

can slide pass right through the rotor element.

The rotor element

300

has a cavity

306

for receiving a piezoelectric element formed by a single plate

308

passing longitudinally through the cylinder

30

over substantially its entire length and secured in its center

310

to said rotor element. The bimorph thus constituted by an upstream portion

308

a

and a downstream portion

308

b

joined by a neutral central zone (i.e. a zone that is inactive from the piezoelectric point of view), has at each of its ends firstly a contact tip

312

,

314

which passes in a rest position (i.e. when not excited) through a corresponding opening

316

,

318

leading to the cavity

306

of the housing

38

perpendicularly to the longitudinal axis of the cylinder, and secondly a blocking element forming a trihedral pin

320

,

322

which, in the above-specified rest position, secures the rotor element

300

to the stator element

302

by being inserted in an opening

324

,

326

of the stator element, and thus prevents any rotation of the tongue. Optionally, bending of the upstream or downstream portion of the piezoelectric plate

308

when the key

10

is inserted into the housing

38

can take place against resilient means, e.g. a spring

328

,

330

, placed at each free end of the plate

308

against its face opposite to its face receiving the contact tips

312

,

314

. Naturally, each of the upstream and downstream portions of the piezoelectric plate

308

has its own electrical contacts (not shown) which are connected to the electronic means of the cylinder represented diagrammatically by reference

332

and advantageously located in the tongue

36

.

In the example shown in

FIG. 10

, the key also has a piezoelectric plate

334

which is embedded at one of its ends in the body

336

of the key and which has a space carrying a serrated profile

338

, while its other face is free, such that said plate

334

is subjected to reciprocating pivoting motion about its anchor point as a result of pressure from the contact tip

312

,

314

running along the serrated profile

338

while the key is being inserted into the cylinder. Like the plate

308

of the cylinder, the plate

334

of the key has electrical contacts

340

connected to the electronic means

342

of the key.

The operation of the locking system made in this way is very simple. When the key

10

is inserted into the housing

38

of the dual cylinder

30

, the successive bending of the plate

334

of the key and of the front plate

308

a

of the cylinder will cause energy to accumulate in the rectifier and storage means

332

,

342

both in the key and in the lock (

FIGS. 1

,

2

;

6

and

7

).

Once the key is fully inserted, the upstream blocking element

320

is released and the accumulated energy is at a maximum. The piezoelectric plates then form a coupled oscillator through which identity codes can be interchanged between the processor means

332

,

342

. If the codes match, the accumulated energy can be connected via the contacts of the downstream plate

308

b

which, under the effect of said energy, will bend and thus release the downstream blocking element

332

for a short instant of time, and it is only during this short instant of time that it is possible to rotate the tongue that has been released in this way. Naturally, various means (not shown) are provided to ensure that the key is not withdrawn until it has performed one complete turn (e.g. a device known as a “captive hook”). It will also be observed that the key-expelling means which is pushed back while the key is being inserted serves to guarantee that the lock is actuated by one key, and by one key only.

FIGS. 16 and 17

show another embodiment of a cylinder

30

and a key

10

also provided with piezoelectric power generator means. As before this cylinder has a rotor element

400

secured to the tongue

36

and surrounded by a stator element

402

. The rotor element has the housings

38

for receiving the key

10

and in which the key-expelling piston

404

can also slide passing right through.

Whereas in the embodiment of the cylinder shown in

FIGS. 14 and 15

, the piezoelectric element is constituted by a single piezoelectric plate having a neutral central zone, in this new embodiment, the piezoelectric element is constituted by two distinct piezoelectric plates

406

,

408

disposed in two cavities

409

,

410

of the rotor element

400

, each extending substantially over the entire length of the cylinder. Since the energy generated by a piezoelectric element is proportional to its dimensions, it will readily be understood that this structure is advantageous since it enables the same key to recover substantially twice as much energy as in the preceding case. Each plate

406

,

408

is embedded at one of its ends in the rotor element, with its other end having two opposite contact tips

412

,

414

;

416

,

418

which, in a rest position (i.e. in the absence of excitation), open out into opposite sides of the housing

38

and also a blocking element forming a trihedal pin

420

,

422

which, in the above-specified rest position, secures the rotor element

400

to the stator element

402

and is inserted in an opening

424

,

426

of the stator element. The bending of one or the other of the piezoelectric plates

406

,

408

on insertion of the key

10

in the housing

38

can optionally be performed against resilient means, e.g. a spring

428

,

430

, placed at each of the free ends of the plate

406

,

408

, on its face opposite from its face supporting the blocking means

420

,

422

. In addition, each of the piezoelectric plates has electrical contacts (not shown) which are connected to the electronic means of the cylinder (not shown).

The key

10

more particularly intended for cooperating with the type of cylinder described above is shown in FIG.

16

. This key also has a piezoelectric plate

434

with a serrated profile

438

(which profile can be made simply, for example, by covering the plate in profiled resin) and has one of its ends embedded in the body

436

of the key so that when the key is inserted in the cylinder, the pressure of the opposing contact tips

412

,

414

;

416

,

418

along the serrated profile

438

causes said plate

434

to perform reciprocating pivoting motion about its anchor point. It will be observed that in order to protect the piezoelectric plate as well as possible from any external contact other than that which it makes with the contact tips, the plate is advantageously accessible only via lateral grooves in the key. Like the plates

406

and

408

of the cylinder, the plate

434

of the key has electrical contacts

440

connected to the various electronic means of the key given a single reference

442

.

This variant embodiment operates in identical manner to the preceding embodiment. It should merely be observed that in this new variant, when the codes match, the energy accumulated while the key is being inserted is now discharged via the second plate

408

and not as before via the second portion of the sole plate

308

b

. In this case also, the discharge serves to release the second blocking means

422

, with the first blocking means

420

naturally being released by insertion of the key.

FIGS. 18

to

20

show an embodiment of a cylinder

30

and a key

10

in which the power generator means are implemented in magnetic form. This cylinder, as shown in

FIG. 18

, is constituted essentially by a stator element

502

surrounding a rotor element

500

which in this embodiment is constituted by no more than a single rotary tongue

36

whose various component parts are described in detail with reference to

FIGS. 19

a

and

19

b

. The stator element

502

has two similar modules

506

and

508

each received at the inlet of the cylinder

30

and having housings

38

passing therethrough to receive the key

10

, and in which it is also possible for a key-expelling piston

504

to slide whose structure is described in greater detail with reference to

FIGS. 20

a

and

20

b

. Each module

506

,

508

is constituted simply by a soft iron tube

510

,

512

provided with a plurality of washers likewise made of soft iron and regularly spaced apart so as to separate four coils

514

,

516

,

518

, and

520

;

524

,

526

,

528

, and

530

disposed in the tube around the housing

38

. The windings of these coils and their interconnections are made as described above (see

FIG. 13

) and their links with the various electronic means

46

to

64

are likewise as described above (see FIG.

2

).

An embodiment of the key for co-operating with the type of cylinder having magnetic components is also shown in FIG.

18

. The key has a moving magnetized shank

532

(movable under drive from displacement means

534

) comprising a soft iron body provided with four bipolar annular magnets

536

,

538

,

540

, and

542

, and forming a magnetic core for four coils

544

,

546

,

548

, and

550

.

The tongue

36

which is shown in greater detail in

FIG. 19

a

(

FIG. 19

b

being an end view of

FIG. 19

a

) comprises a conventional external structure with a cylindrical body

560

from which a fin

562

projects radially. The fin has an orifice

564

passing therethrough in which there is placed a centering device

566

, e.g. formed by a ball-and-spring assembly

568

,

570

, and

572

suitable for co-operating with complementary cavities

574

and

576

formed in register therewith in the stator element

502

. The body

560

is also pierced by an opening

578

for receiving two hollow annular pieces of soft iron

580

and

582

placed one against the other while leaving an empty disk-shaped space

584

between them. The inside walls

586

and

588

of these annular pieces in contact with this empty space also include respective slots

590

and

592

which, in a tongue-release position, receive a slightly magnetized rotary blocking blade carried by the key-expelling piston

504

.

The piston is described below with reference to

FIGS. 20

a

and

20

b

which show a face view and a profile view. It comprises a body

600

that fits in the housings

38

in which it slides and that is provided with a central core

602

of soft iron with the slightly magnetized rotary blades

608

,

610

being pivotally mounted about respective axes

604

,

606

, each blade having a portion extending beyond the central core

602

and in line therewith (in the rest position).

The assembly is covered in a non-magnetic material such as brass or resin

612

(except for the blade

608

or

610

which must be free to pivot about its respective axis

604

,

606

). Two soft iron mechanical interfaces

614

and

616

are placed at respective ends of the piston, thereby completing the structure thereof, these disks being adapted to receive exactly the mechanical interface means

12

of the key (for example, a blade/slot system could be entirely suitable for providing such a rotary drive link).

The operation of this embodiment of the invention is described below with reference to

FIGS. 21

to

23

.

FIGS. 21

a

and

21

b

show the magnetic flux distribution in the coils of the cylinder

30

as a function of two different and successive positions of the key

10

. It can be seen that shifting the key by one serration reverses the flux perceived by each coil because of the opposite polarities carried by pairs of adjacent magnets, which polarities determine the direction of the flux. Fully inserting the key will therefore generate four alternations of alternating current of amplitude that increases from alternation to alternation, with rectification thereof being performed by the rectification and storage means. A similar process takes place in the key when the magnetized shank is ejected from its sheath either prior to the key being inserted as shown in

FIGS. 9 and 10

that relate to a piezoelectric version of the key, or at the moment of insertion, thereby enabling the key to have self-contained power supply and communication.

When the key is fully inserted in the cylinder of the lock (FIG.

18

), a closed magnetic circuit is established including a contribution from the structure of the key, as shown in

FIG. 22

, with magnetic flux travelling through the coils of the key and of the lock and looping via the magnetized shank. In this configuration, the assembly forms a perfect coupled transformer whose resonant frequency can be selected as a carrier frequency for communication between the processor means of the key and the lock previously powered by the rectifier and storage means (a communications link by mere insertion can also be envisaged). After codes have been interchanged, and assuming they match, the energy accumulated during insertion of the key is discharged via the electrical contacts of the second module, thereby generating an intense magnetic field that causes the rotary blade

610

of the key-expelling piston

504

to pivot (to take up a stable vertical position), and thus, by becoming inserted in the slots of the tongue secures it to the piston, thereby enabling the assembly to be driven by the shank of the key (because of the mechanical interface means

12

). After a short determined period or when the key is extracted, the lock is again prevented from operating, with the magnetized rotary blade returning to its initial horizontal position.

It will be observed that the invention, both in its magnetic version and in its piezoelectric versions makes it possible to provide a locking system that is particularly optimized in that the power generator means of the lock associated with the power generator means of the key suffice to perform the three essential functions of the system: the function of power generation is performed by a mechano-electrical connection of a deformation (piezoelectric version) or of a displacement (magnetic version) causing electrical charge to be stored in storage means, the communications function is implemented by high frequency coupling between the means of the lock and of the key, and the actuator function, given the reversibility of the means used, is implemented by electromechanical conversion of the previously stored electrical charge into a deformation or a displacement.

Naturally, the fully optimized version of the invention can also be implemented in a more limited configuration, in particular by providing for data to be communicated between the lock and the key or energy to be transferred from the key solely by means of a direct electrical contact, e.g. as shown in FIG.

10

.

Number	Name	Date	Kind
4829296	Clark	May 1989	A
4912460	Chu	Mar 1990	A
4980680	Knoll	Dec 1990	A
5140317	Hyatt	Aug 1992	A

Number	Date	Country
5-37404	Feb 1993	JP
6-73930	Mar 1994	JP
6-73931	Mar 1994	JP
WO-8002710	Dec 1980	WO

Electronic locking device

Information

Patent Number

Date Filed

Date Issued

Inventors

Original Assignees

Examiners

Agents

CPC

US Classifications

Field of Search

US

International Classifications

Abstract

Description

Claims

Priority Claims (1)

PCT Information

US Referenced Citations (4)

Foreign Referenced Citations (4)