Anti-theft protection for motor vehicles, in particular for passenger cars

摘要

An anti-theft protection for passenger cars has an ignition lock (1) which is connected via a battery line (2) to the battery (6) of the motor vehicle and via a starting line (3) to the starter (9) of the motor vehicle. The starting line (3) is connected to the battery line (2) in the ignition lock (1) when an ignition key is turned to a predetermined position in a lock switch (18) of the ignition lock (1). An electric circuit (20) in the ignition lock (1) has an encoder (20). A decoder (25) with a relay switch (19) is arranged in the vicinity of the starter (9). The encoder (20) is connected to the decoder (25) by a security line (4). The relay switch (19) is connected in series with the lock switch (18) in the starter circuit. When the ignition key assumes the predetermined position in the lock switch (18), a pulse sequence occurs at the output (23) of the encoder (20) which is connected to the security line (4). The decoder (25) then closes the starter circuit, interrupted by the open relay switch (19), for a predetermined time when the predetermined pulse sequence is present at the input (26) of the decoder (25).