Patent ID: 7733199

Claim:
An electrical circuit breaker having a protective function in case of a fault, the circuit breaker comprising: a switch mechanism moveable between an ON position and an OFF position; an electromagnetic tripping unit configured to act mechanically on the switch mechanism in response to a switch-OFF command, the tripping unit including: a tripping coil; an actuator unit configured as a rotating mechanism for moving the switching mechanism between the ON and OFF positions as well as for resetting the tripping unit after a trip, the actuator unit having a drive shaft operatively connected to the switch mechanism; a pressure spring; a solenoid armature configured as a tripping tappet disposed in the tripping coil, the pressure spring biasing the solenoid armature in a tripping direction; a permanent magnet holding the solenoid armature in the ON position of the switch mechanism and in a reset state of the tripping unit when the tripping coil is without power supply; a tripping lever rotatable by the solenoid armature and acting on the switch mechanism; and a mechanical operative connection disposed between the drive shaft and the tripping unit, the mechanical operative connection configured to reset the tripping unit when the drive shaft is moved out of the OFF position in a direction opposite from a rotational movement for switching on, wherein the mechanical operative connection includes a double-arm lever having a first arm acted upon by at least one catch device on the drive shaft and having a second arm configured to bring about the resetting movement of the tripping unit, and the mechanical operative connection is configured so that a rotation of the drive shaft is converted into a counter-rotation of the double-arm lever and the rotation of the double-arm lever becomes a linear movement of the solenoid armature, and wherein the second arm includes a prong and in the solenoid armature includes a groove configured to engage with the prong.