Electrical transmission or interconnection systems – Vehicle mounted systems – Automobile
Reexamination Certificate
1999-06-28
2001-03-13
Jackson, Stephen W. (Department: 2836)
Electrical transmission or interconnection systems
Vehicle mounted systems
Automobile
C307S009100
Reexamination Certificate
active
06201317
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention pertains to a device wherein in the area of lock cylinders, both mechanical and electrical components are used, which, when a key is used to operate the lock, activate or deactivate electrical functions by way of the electrical switching device. The lock cylinder consists of a stationary cylinder housing with a rotatable cylinder core inside, which can be rotated by a properly fitting key. The mechanical components comprise a key channel which accepts the key, tumblers in the cylinder core, and a locking channel for the tumblers in the cylinder housing. The electrical components include at least one permanent magnet on the circumference of the cylinder core and a sensor in the cylinder housing, which, when the key is used to operate the cylinder core, responds to the permanent magnet. The sensor is connected to an evaluator, which activates the electrical switching device when the key operates the lock. The lock cylinder of a device such as this is preferably installed as a steering lock in the area of the steering column of a motor vehicle, and the electrical switching device contains the electronics of the engine. Devices of this type are used to protect the motor vehicle against theft. The device is then referred to as an “electronic device for preventing a vehicle from being driven away”.
2. Description of the Related Art
A device such as this is known from U.S. Pat. No. 5,186,031. In this device, the vehicle is protected from theft even after the thief has pulled the cylinder core of the lock cylinder axially out of the cylinder housing in order to manipulate the interior of the cylinder housing. In this known device, the cylinder core has a radially spring-loaded retaining element, which, when the cylinder core is installed, snaps behind a shoulder on the housing. It is thus easy to install the cylinder core axially in the cylinder housing. When the cylinder core is torn out axially by the thief, the retaining element destroys the electrical connections of the sensor in the cylinder housing and thus makes the device inoperable. This anti-theft protection fails, however, when it is possible to use a break-in tool to move the spring-loaded retaining element into its release position with respect to the cylinder housing. In the case of devices in which the cylinder core is not connected to the cylinder housing by means of a snap-in attachment such as this, however, no anti-theft protection is present at all. The reason for this is as follows.
The anti-theft protection of vehicles equipped with these types of lock cylinders consists in that there are a large number of different lock cylinders, each of which has a different set of tumblers in the cylinder core. The cylinder core can thus be rotated only by a certain key which fits this cylinder core. Whereas the cylinder housing has a uniform design, there are many different keys, and each key fits only the corresponding, individual arrangement of tumblers in the cylinder core. To break open a lock equipped with a lock cylinder for which the proper key is not available, it is sufficient for the thief to tear out the cylinder core and replace it with a new cylinder core, for which he has the proper key. It makes no difference to the cylinder housing that the original cylinder core has been replaced by a new one for which the thief has the proper key. This theft strategy also functions in the case of the known device in which the cylinder core has a permanent magnet and the cylinder housing has a sensor, because the new cylinder core bought with the key also has a permanent magnet, which is then able to perform the same functions in the interior of the cylinder housing as the permanent magnet of the torn-out cylinder core. The known device thus does not offer adequate protection.
SUMMARY OF THE INVENTION
The invention is based on the task of developing a reliable device of the aforementioned kind, which is characterized by a high level of protection against manipulations of the lock cylinder by unauthorized persons. This is accomplished according to the invention by means of the following features:
a group of different cylinder cores is assigned to the cylinder housing with a sensor in a predetermined, fixed location;
where, although the cores have the same tumblers and can be actuated by the same key, they differ from each other magnetically with respect to one at least one of the permanent magnets;
in that, for each application of the device, one cylinder core is selected from this group and paired with the cylinder housing to form a magnet-specific lock cylinder;
which, because of the selected cylinder core, forms a lock cylinder with a specific magnetic code;
in that the sensor detects the magnetic differences in the magnetic code upon operation of the cylinder core by the key;
in that the evaluator can be set or programmed for the specific magnetic code of the lock cylinder used in the device; and
in that, after this setting or programming, the evaluator will respond by actuating the switching device upon operation of the key only when the selected cylinder core upon which the magnetic code is based is in the lock cylinder.
The invention introduces a new variant of a lock cylinder for the known device. What is available now is a family of cylinder cores which differ from each other not only with respect to the arrangements of their tumblers, these cores requiring different keys, of course, but still being capable of working together with the same cylinder housing, but also with respect to their magnetic properties, which still allows them to be installed in the same cylinder housing. According to the invention, therefore, there are lock cylinders with identical housings which differ not only mechanically from each other on the basis of their key code but also electrically as a result of a “magnetic code”. When, in the case of the device according to the invention, a thief tears out the cylinder core with its permanent magnet and replaces it with a new cylinder core also having a permanent magnet, he cannot circumvent the device according to the invention even though he has the right key. Because of the differences according to the invention between the permanent magnets of the various cylinder cores, the new lock cylinder assembled in this way will usually have a different magnetic code. This is detected by the sensor, which therefore will not actuate the evaluator when the key is used to operate the newly installed cylinder core. The evaluator in the invention is still set or programmed for the old code. The replacement of the cylinder core does not benefit the thief in any way when the device according to the invention is present; the sensor is able to tell that the cylinder core is “wrong”. The electrical switching device is therefore not activated, and the attempted theft fails.
If it is possible not only to use the same number of permanent magnets but also to mount them at the same point on the individual cylinder cores, the device will be especially simple in its design and also inexpensive to manufacture, provided that the cylinder cores to be installed in a standard cylinder housing can still be made magnetically different from each other. In turns out that, to make them magnetically different from each other, it is sufficient to vary their field direction. This can be easily done at the time the permanent magnets are installed in the individual cylinders. Permanent magnets with a specific orientation of their north pole-south pole axis are used, and sensors which are able to detect the orientation of the magnetic field are provided. The number of different magnetic codes available depends only on the accuracy with which these sensors can distinguish between different magnetic field orientations. The selected rotational position of the permanent magnet at the time it is installed in the cylinder core determines the magnetic code. This is very easy to accomplish. As a result, the devices according to the invention can be manufactured at very low co
Kemmann Harald
Reikher Alexander
Simon Jörg
Huf Hulsbeck & Furst GmbH & Co. KG
Jackson Stephen W.
Kueffner Friedrich
Polk Sharon
LandOfFree
Device with a key-operated lock cylinder and with an... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device with a key-operated lock cylinder and with an..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device with a key-operated lock cylinder and with an... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2508467