Patent ID: 7699144

Claim:
An active break release device driven by a second motor and externally attached to the door controller, which is used for the triggering of automatic brake releasing to close the safety door in unexpected electricity failure condition, in which said door controller ( 1 ) have a housing ( 1 ′) for receiving a first motor ( 2 ), the driving torque of which is transferred through a rotary shaft ( 3 , 3 ′) to a reel for winding the door; a braking device ( 4 ) is provided at the outside of said rotary shaft ( 3 , 3 ′), which includes a braking portion ( 40 ) normally located at a brake activating position, and located at a brake releasing position when the first, motor ( 2 ) is energized, wherein said active break release device comprises: at least a brake releasing rod ( 44 , 44 ′), one end of which activates the braking portion ( 40 ) to release brake by leverage action force, while the other end of which extending to the outside of the door controller ( 1 ); at least a second motor ( 50 , 50 ′) provided externally at the door controller ( 1 ), the driving torque of which is applied to the other end of the brake releasing rod ( 44 , 44 ′) and cause to move thereof, the second motor being temporarily supplied with electricity through a circuit having a backup power source in the case of unexpected electricity failure condition, and the braking portion ( 40 ) being driven by said second motor ( 50 , 50 ′) to release the braking.