Communications: electrical – Land vehicle alarms or indicators – Of burglary or unauthorized use
Reexamination Certificate
1999-07-26
2001-02-27
Lieu, Julie (Department: 2736)
Communications: electrical
Land vehicle alarms or indicators
Of burglary or unauthorized use
C340S539230, C340S542000, C307S010200
Reexamination Certificate
active
06194997
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to an antitheft system for a motor vehicle in which locking or unlocking of one or more doors is made possible only after authorization is proven.
In antitheft systems for motor vehicles, in particular in the case of keyless access control systems, a request signal is transmitted to a portable code transmitter after triggering through the use of an activation switch on a door. The code transmitter responds automatically with its response signal if it has received the request signal. If the response signal itself is received in the motor vehicle and if it proves to be authorized after comparison with a reference signal expected there, the doors of the motor vehicle are locked or unlocked.
In an antitheft system which is known from German Published, Non-Prosecuted Patent Application DE 41 23 654 A1, a switch in the interior is activated when the occupants leave the motor vehicle. As a result, a request signal which firstly addresses the code transmitter in the interior is triggered.
If no signal is sent back by the code transmitter from the interior, the request signal is transmitted to the exterior. If a response signal is transmitted back from there, the vehicle can be locked, since it is assumed that the code transmitter is outside the motor vehicle. However, if the user with the code transmitter moves away from the vehicle too quickly, the motor vehicle may possibly no longer receive the response signal. The vehicle then remains unlocked.
In a further antitheft system which is known from U.S. Pat. No. 4,805,723, the doors of the motor vehicle are automatically locked if the doors are closed and no one is subsequently detected in the motor vehicle. However, in that context it may be the case that the driver has forgotten his or her key in the motor vehicle and can then no longer enter his or her motor vehicle again since it is already locked.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide an antitheft system for a motor vehicle, which overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type and which provides a high degree of security against theft, even if a driver only briefly leaves his or her motor vehicle.
With the foregoing and other objects in view there is provided, in accordance with the invention, an antitheft system for a motor vehicle, comprising a central control unit connected to the locks for locking and unlocking the locks; a trigger switch connected to the control unit, the trigger switch sensing closing and opening of one of the doors; at least one antenna connected to the control unit for transmitting a request signal into the interior; a portable code transmitter for receiving the request signal and automatically transmitting back a response signal after previously receiving the request signal; and an interior monitoring device connected to the control unit, the interior monitoring device establishing if anyone is in the interior; the trigger switch activated by closing one of the doors to cause the control unit to activate the interior monitoring device and the at least one antenna to test for the presence of a person in the interior and to transmit the request signal into the interior, and the interior monitoring device causing the control unit to lock all of the door locks if no one is subsequently detected in the interior and no response signal is received.
When the door of the motor vehicle is locked, the interior monitoring device detects whether or not anyone is still in the interior. If this is not the case, a transceiver unit detects whether or not a valid code transmitter is present in the interior of the motor vehicle. If this is not the case either, the doors are automatically locked without the user having to perform a particular action to bring this about.
In accordance with another feature of the invention, the trigger switch is a door contact switch switched on and off by closing one of the doors associated with the door contact switch.
In accordance with a further feature of the invention, the at least one antenna also transmits the request signal into the exterior and the control unit monitors if a response signal is received from the exterior.
In accordance with an added feature of the invention, the user can be warned visually or audibly that there is still a person or a key in the interior of the vehicle.
In accordance with an additional feature of the invention, there is provided a switch in or on the motor vehicle which, when activated, prevents the doors of the motor vehicle from being locked under any circumstances.
In accordance with yet another feature of the invention, the interior monitoring device includes a seat occupation detection device having a capacitor with at least one electrode disposed in a seat.
In accordance with yet a further feature of the invention, the interior monitoring device has ultrasonic sensors or infrared sensors and ultrasonic receivers or infrared receivers for respectively transmitting and receiving signals and comparing the signals with stored patterns for detecting the presence of a person in the interior.
In accordance with yet an added feature of the invention, the at least one antenna is disposed within the motor vehicle and transmits the request signal only into the interior.
In accordance with yet an additional feature of the invention, the at least one antenna is a loop antenna having an air coil with a plurality of turns disposed between a door lining and a door panel of at least one of the doors.
In accordance with a concomitant feature of the invention, there are provided electric motors connected to the control unit for at least partially opening or completely closing at least one window, a sliding roof or a top as a function of the locking and unlocking.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in an antitheft system for a motor vehicle, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
REFERENCES:
patent: 4805723 (1989-02-01), Aoki et al.
patent: 41 23 654 A1 (1993-01-01), None
patent: 4123654 (1993-01-01), None
Buchner Reiner
Roehrl Thomas
Wagner Dieter
Greenberg Laurence A.
Lerner Herbert L.
Lieu Julie
Siemens Aktiengesellschaft
Stemer Werner H.
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