Patent ID: 7448426

Claim:
A power-off door closing device 20 of a fire proof rolling door, which is provided on one side face of a cover plate 11 of a rolling machine 1 for rotating a rolling shaft, a receiving chamber 10 a being formed on this side face by a tail cover 10 ; a brake device 30 being fixed on the other side face of said cover plate 11 , a braking pin 34 included in the brake device 30 being extended into said receiving chamber 10 a , wherein that said device comprises: a brake actuation rod 21 , one end 21 a of which being fixed on said braking pin 34 , the other end being formed as a free end 21 b; a clamp member 22 , one end 22 a of which guides a sliding block 23 , the other end being formed as a pivot end 22 b , wherein one end 23 a of said sliding block 23 abuts against the free end 21 b of said brake actuation rod 21 , and the other end being a connecting end 23 b; a bent arm 24 having a first end 24 a and a second end 24 b , said first end 24 a being supported on the pivot end 22 b of said clamp member 22 and said first end 24 a including an extension end 241 which moves together with the connecting end 23 b of the sliding block 23 by a support arm 25 connected between said bent arm ( 24 ) and said connecting end ( 23 b ); a solenoid 26 , having a sliding lever 261 provided at the center thereof and stored with potential energy of a spring 262 , said sliding lever 261 having a first end 261 a and a second end 261 b in which said first end 261 a moves together with the second end 24 b of the bent arm 24 , and said first end 261 a being acted by the spring 262 to be pushed outwardly in axial direction under de-energized condition of said solenoid; a control circuit used to control the solenoid 26 for brake-applying under energized condition or for brake- releasing under power-off condition, thus, said brake is brought into released state under abnormal power-off condition to cause the rolling door sliding down by its own weight to close.