WO1990007045A1

WO1990007045A1 - Process and device for operating a locking system

Info

Publication number: WO1990007045A1
Application number: PCT/DE1989/000792
Authority: WO
Inventors: Hans Kolb
Original assignee: F + G Megamos Sicherheitselektronik Gmbh
Priority date: 1988-12-22
Filing date: 1989-12-22
Publication date: 1990-06-28
Also published as: EP0402442A1

Abstract

Top-class cars possess a central locking system. When this system is actuated, a mechanical contact generates an electrical signal which is transmitted to the other locks. This contact can be manipulated, which means that the central locking system can be actuated by unauthorized persons. According to the invention, two permanent magnets (18) are fastened to the cylinder (14) of the cylinder lock and two sensors (20) are lodged in the cylinder housing (12). When the cylinder turns, the permanent magnets generate a rotary field which is detected and then analysed by the sensors. In the absence of untoward circumstances, a control signal is generated. The lock according to the invention cannot be manipulated mechanically, either with a wire or with any similar object. Nor can it be influenced by a magnetic field.

Description

Method and device for actuating a locking system

The invention relates to a method for actuating a locking system, in particular a central locking system of a motor vehicle with a lock consisting of a housing with a cylinder which can preferably be rotated therein with a flat key, with generating measured values when the cylinder rotates, with storage of the during a first rotation Measured values generated by the cylinder, comparing these stored measured values with the measured values generated when the cylinder is rotated again and generating a control signal when the equality or approximate equality between the stored values and the measured values arising during the renewed rotation is determined. The invention further relates to a device for performing this method with a lock with a housing and a cylinder rotatable therein, with a rotating with the cylinder and an electrical, magnetic or optical _. Measured value generating device, with at least one sensor on the housing for detecting the measured value, with a memory and with a control device.

A control for the central locking of a motor vehicle is known (DE-OS 3 426 508). The key and the cylinder of the cylinder lock of this central locking system have the usual mechanical tumblers. In addition, the key contains magnetically, electrically or optically readable information. When the key is inserted into the lock cylinder, it is read. If this read corresponds to a stored information, the lock can be opened by turning the key further. During this rotation of the key, the information read is also stored in a memory as new target information. This control is intended to make it difficult for an unauthorized person to actuate the central locking. Only if the key used by the unauthorized person has the correctly shaped beard for actuating the tumblers and the correct one If the key contains additional information, the key can be used. Also known is a method for coding a door lock operated with a remote control (DE-OS 3 520 397). This method uses a transmitter and a receiver. The receiver contains a comparison circuit which emits a control signal if the received coding matches a stored code. The receiver also contains a circuit that learns the coding emitted by the transmitter.

The mechanical locks of motor vehicles have been continuously improved in recent years. The number of tumblers and their effectiveness has been continuously increased. Penetration into the properly locked vehicle with a key is almost impossible.

With increasing demand from vehicle buyers for more locking convenience, central locking systems were increasingly installed in the vehicles. These central locking systems - with servo assistance - lock all other existing locks when one of the locks on the vehicle is locked. All common central locking systems are activated by electrical signals. An electrical signal is derived from the mechanical lock, which gives the command for central locking to the mechanism provided.

The mechanical lock on vehicles is a very precise mechanical part. In almost all central locking systems, the electrical signal required for the closing or opening process is generated by means of a mechanical microswitch. This is attached to the lock. When the cylinder is turned into its end position, it makes contact. This microscale - ^{^} ter must meet the highest precision requirements, since it must be attached to the cylinder of the lock, it is very strongly exposed to moisture and corrosion.

This microswitch ^" represents the in modern locking systems Weak point of the entire system. If a thief manages to operate the microswitch directly past the lock with a thin, wire-like object, he can use this manipulation to open the vehicle without a key. This means that any type of mechanical switch for coupling the mechanical lock with the electronics of the central locking system is very poorly suited.

Proceeding from this, the invention is based on the object of coupling the lock and electronics without a mechanical connection in such a way that even an intelligent thief cannot outsmart the coupling and is not able to generate the control signal from the outside by any mechanical manipulation. The solution to this problem results according to the invention in a method of the type mentioned at the outset by detecting and storing measured values generated on the housing at two separate locations during the first rotation, which are generated when the rotation is repeated. Measured values are also detected and compared with the stored ones, and the control signal is generated in the case of equality or approximation. The measured values are magnetic, electrical or optical quantities. To simplify the description, the invention is explained below using the example of a magnetic measured value. In the rotating cylinder, for example, a magnetic field is generated by one or more permanent magnets, which, due to the geometry of the cylinder and the various metallic materials used therein, can have a very complicated structure. If one measures the magnetic flux density with two corresponding sensors at two different locations on the housing, functions of the magnetic flux densities, which are correlated to one another, result when the key is rotated as a function of the angle of rotation. When the key is rotated properly is always the instantaneous value of the magnetic flux density measured at one point combined with another value of this flux density at the other point The flux densities occurring in both positions have a very specific size in each rotational position of the cylinder. The control signal is only generated if the quantities of the flux densities detected at these points when the cylinder is rotated again match the stored ones. The shape of the metallic key also affects the size of the flux densities measured at these points. When the lock is opened with a duplicate key or lock pick, other flux density values result and the control signal is not generated.

The rotating cylinder and the stationary housing of the lock are expediently designed geometrically and the measuring points are arranged in such a way that the magnetic flux density increases when the cylinder rotates at one measuring point and decreases at the other measuring point.

The two measured values are expediently detected, stored and compared in accordance with the rotational position of the cylinder in the housing or in terms of their time. The two measured values can only be stored and / or compared with one another at a few points in their chronological course. This makes it possible to compromise between the accuracy with which the new measured values are compared with the stored ones and the capacity of the used memories.

A very high accuracy with low capacity of the memory results in a further embodiment, which is ^• characterized in that the temporal course of the two measured values is normalized during the first rotation, a correlation function is formed and stored and in one If the rotation is repeated again, the time course of the two measured values is normalized, a correlation function is formed and the two correlation functions are compared with one another. For each lock, the flux density values measured at the two points are in a specific relationship to one another. This presents itself as a correlation function. Only this is stored and also used for comparison when it is rotated again. All measured values are expediently digitized and stored in digitized form.

The device used to carry out the method according to the invention differs from the prior art in that two sensors are arranged at two points apart in the housing of the lock. The sensors should lie on an arc in accordance with the rotation of the cylinder. Guide plates, which conduct the magnetic flux differently, are expediently located between the two sensors and the cylinder. For this purpose, the guide plates can have different magnetic resistance and / or can be shaped differently. This can achieve the goal already explained, that the magnetic flux at a maximum at one sensor at the other sensor reaches a minimum. To generate the magnetic flux, at least one permanent magnet should be arranged on the cylinder. Likewise, at least one magnetic coil can also be arranged. Finally, a magnetic coil can also be arranged on the cylinder and a coil coupled to the housing as a detector. Finally, one plate pack of a rotary condenser can also be arranged on the cylinder and the other on the housing. With the features of the invention explained above it is achieved that the control signal is not triggered by any mechanical manipulation. To improve the theft protection, the invention provides in a further embodiment that two sensors are arranged in the housing at two points apart. Unless turns in this embodiment -a "thief the cylinder by force in Öff- ^• voltage direction, breaking the breaking point. This ent falls, the magnetic coupling. The control signal is not triggered.

After installing the lock in the vehicle, the electronics learn the correlation between measured values at the two sensor locations as a function of the rotation during the first closing operation. angle of the key. This is done in such a way that a correlation function is derived from the measurement signals determined when opening or closing the first time and this is stored permanently. The electronics then immediately know which pairs of values of the measured quantity, for example the magnetic flux density, must occur. With all future rotations of the key, more precisely the cylinder, the two functions of the measured variable are determined, a correlation function is formed from this and compared with the known target curve, which is accessible in the electronics memory. Only when there is agreement does the electronics of the central locking system be released and opened via a coded signal with corresponding feedback. This way of linking the two signals together makes the entire system completely independent of the speed at which a key is turned in the lock. Turning the key at different speeds only means that when the key is turned slowly, a large number of measured value pairs are recorded by the two sensors and then compared later. The statement about the existing correlation is then even more reliable than when the key is turned quickly. The basic function is exactly the same. The electronics used in the device according to the invention operate digitally. The DERS ^'supplied voltages from the two sensors at the first rotation of the cylinder to be digitized and stored in die¬ ser form. It depends on the compromise to be made between effort and accuracy, how many individual voltages are stored in how many memories. This also determines the size of the angle of rotation over which measurements are made. According to the size of the rotation angle is a more or less broad target profile measured and off ^* stores. Of course, the voltages that arise at the sensors during operation are also digitized and processed in this form.

In order to enable a locking or opening process at any time, the downstream electronics must be constantly ready, the two measured value functions when the key is turned read in, compare and then forward the corresponding signal sequence to the central locking electronics. This would lead to very high power consumption. Therefore, the aim is to decouple a circuit part whose task is to detect an opening process as early as possible, that is to say when the key in the lock begins to be turned, and then to immediately activate the downstream electronics for recording and comparing the recorded measured values - four. This circuit part would have to be implemented in very high-resistance circuit technology. Its power consumption would be very low. Such circuits are known. They are used, for example, in alarm systems in motor vehicles. There are also examples of remote-controlled television sets. In the "ready for operation" condition, they require very little electricity.

When an old cylinder lock is replaced by a new one, its characteristics must be recorded and read into the memory or memories. This must then take place in such a way that reprogramming is only possible if, for example, the ignition key is in the ignition lock of the vehicle and the ignition is switched on. One can also add the requirement that vehicles which are equipped with an anti-theft alarm system must be deactivated when the locking function is reprogrammed.

The method according to the invention is self-adjusting. When the locking system is actuated for the first time, its measured value functions are read in and stored in accordance with the existing circumstances. All tolerances of each castle including "its components are so Stiem from SY ^* already considered and need not be separated yaws korri¬.

In principle, an abundance of other measured variables can be used to monitor a closing or opening process according to the principle given above. The prerequisite is that the measured variable in the rotating cylinder or in the fixed stationary cylinder housing is detected, a clear electrical signal can be derived. In this case, however, only effects can be used which can be manipulated in such a way that a measured value which is clearly variable via the angle of rotation of the key is obtained and which can be converted into an electrical signal in such a way that a characteristic property of this electrical signal, for example its amplitude, frequency or phase depends on the angle of rotation.

For this purpose, it is also possible to separately attach a sensor to the lock so that a measurement function with the properties described above can be obtained. Examples of this are the arrangement of two plunger coils, the detection of their inductance, the plunger coils should be divided into two, the arrangement of a butterfly capacitor and the detection of its capacitance.

In general, the sensors used in the invention should be designed in such a way that there is no monotonous function of the measured value on each side via the angle of rotation. This can be achieved, for example, by the fact that _. the sensor or the surfaces surrounding it are designed according to a certain geometric shape. Furthermore, the measured value should run in the vicinity of the rotation angle T = 0 with the steepest possible tangent. This facilitates the detection of the initiated rotation of the key in the lock, which is expediently carried out with a separate circuit part, which can be designed with high resistance. In order to really achieve the desired theft protection, the sensor should be partly on the fixed part of the lock and partly on the rotatable part. Sensor is understood here to mean both the part producing the measured variable and the part of a circuit or arrangement which receives the measured value. Under no circumstances, however, should the sensor arrangement be designed in a self-contained housing or partial housing, which as a whole can be separated from the lock. After removing the lock, this sensor would then be freely accessible. accessible and would provide the correct measurement signals if rotated accordingly.

The sensors should also be designed in such a way that they deliver measurement signals which also depend on the mechanical tolerances of the individual lock specimen. This further complicates the simulation of the measured value curve required for opening.

In the above, the invention was explained using the example of the lock of a motor vehicle. The following exemplary embodiment also relates to a motor vehicle lock. However, the invention can be applied far more generally. It can be used wherever a rotation is to trigger an electrical control signal and the contact previously usually used is to be arranged in such a way that it cannot be reached with the key or with any other mechanical element and can thus be manipulated and closed.

The invention will now be further described using the example of the embodiment shown in the drawing. In the drawing is:

Fig. ^'L is a simplified schematic representation of a Erfin dung designed according Zylinderεchlosses,

Fig. 2 shows the course of the flux density at the two sensors when turning the cylinder and

FIG. 3 is a -schematische "representation of a particular excluded ^* staltung the cylinder.

Fig. 1 shows a cylinder lock having a cylinder housing 12, which is arranged in this rotatable cylinder 14 with a eingesteck¬ th key 16, two attached to the end face of the cylinder 14 the permanent magnet 18 and two in the cylinder housing 12 ^sensors' 20 relative to the rotational axis of the cylinder 14, the two permanent magnets 18 are offset from one another by 180 °. The flux densities B that occur when the cylinder 14 is turned at the two sensors 20 or measuring points 1 and 2 are shown in FIG. 2 as a function of the angle of rotation. Corresponding to the mechanical displacement of the two permanent magnets 18, the flux densities B and B are also offset from one another by approximately 180 °. At a rotation angle of zero the flux density B ^ reaches. a maximum at measuring point 1, while the flux density Ε> ₂ at measuring point 2 is close to its minimum. The course of the flux densities B and B over the angle of rotation is characteristic of the respective cylinder lock. When the lock is operated for the first time, the two flux densities B .. and B "are stored in a digitized form at a certain angle of rotation or over a range of angles of rotation. Likewise, a number which is derived from a mathematical relationship between the two flux densities can also be stored. When the lock is actuated again in practical use, the electronics determine whether the then occurring flux densities B ₁ and B_ match the stored value or the stored values. at

- A complete or almost complete match, the control signal is triggered.

In the embodiment shown in FIG. 3, a predetermined breaking point 22 is provided in the cylinder 14. This lies at the inner end or at a distance from the handle of the key 16. FIG. 3 also shows various tumblers 24. When this cylinder 14 is turned violently, for example with a screwdriver, the predetermined breaking point breaks. The -of the ^* innenlie- .genden end cylinder 14 mounted permanent magnets 18 advertising ^* - - does not move to. The flux density at the sensors 20 thus remains constant. The control signal is not triggered. When the screwdriver is inserted, the magnetic conductivity of the cylinder is also changed. This means that the magnitudes of the magnetic fluxes generated when turning no longer match the stored magnitudes. This also means that the control signal is not triggered.

Claims

Patent claims

1. Method for actuating a locking system, in particular a central locking system of a motor vehicle with a lock made of a housing (12) with a cylinder (14) that can be rotated in this preferably with a flat key (16), with generating measured values when the cylinder rotates ( 14), by storing the measured values generated when the cylinder (14) is first rotated, comparing these stored measured values with the measured values generated when the cylinder (14) is rotated again and generating a control signal when the equality is established or approximate equality between the stored values and the measured values resulting from the renewed rotation, characterized in that measured values generated on the housing (12) at two spaced apart locations during the first rotation are detected and stored, which are obtained during an er measured values generated by the new rotation are also detected and compared with the stored values and the control r signal is generated in the case of equality or approximate equality.

2. The method according to claim 1, characterized in that the two measured values are detected, stored and compared in accordance with the rotational position of the cylinder (14) in the housing (12) or in their temporal course.

3. The method according to claim 2, characterized in that ^* the two measured values are only stored at a few points in their temporal course and / or are compared with one another.

4. The method according to any one of claims 1 to 3, characterized ge indicates that the temporal profile of the two measured values normalized during the first rotation, a correlation radio tion is formed and stored, and when the rotation is repeated, the time profile of the two measured values is normalized again, a correlation function is formed and the two correlation functions are compared with one another.

5. The method according to any one of claims 1 to 4, characterized ge indicates that the measured values are digitized and stored in digitized form.

6. Device for carrying out the method according to claims 1 to 5 with a lock with a housing (12) and a cylinder (14) rotatable therein, with a rotating with the cylinder (14) and an electrical, magnetic or optical measured value generating device (18), with at least one sensor (20) on the housing (12) for detecting the measured value, with a memory and with a control device, characterized in that two sensors (20) in the housing (12) on two apart locations are arranged.

7. The device according to claim 6, characterized in that the sensors (20) are arranged on an arc corresponding to the rotational movement of the cylinder (14).

8. Device according to one of claims 6 or 7, characterized in that between the two sensors (20) and the cylinder (14) the magnetic flux differently conductive baffles are arranged.

9. Device according to one of claims 6 to 8, characterized in that at least one permanent magnet is arranged on the cylinder.

10. Device according to one of claims 6 to 8, characterized in that at least one magnetic coil is arranged on the cylinder (14). -ß-

11. The device according to claim 10, characterized in that on the cylinder (14) a magnetic coil and on the housing (12) ei¬ ne is arranged with this coupled coil.

12. Device according to one of claims 6 to 11, characterized in that the cylinder (14) and the housing (12) the other plate pack of a variable capacitor is arranged an¬.

13. Device according to one of claims 6 to 12, characterized ge indicates that tumblers (24) are arranged over a larger part of the length between the housing (12) and cylinder (14) that the device generating the measured value (18th ) is arranged in the area of the cylinder (14) remote from the key handle and the cylinder (14) has a predetermined breaking point (22) at the end of this area facing the handle of the key (16).