Abstract: A brake structure for a roll-up door includes a brake drum fixed to a transmission shaft of a speed reducer. The brake drum receives a pair of brake shoes in opposite inner sides thereof. The brake shoes are pivotably connected to each other at an end of each brake shoe. A linking resilient member is connected between the free ends of the brake shoes. A brake pad is attached to a surface of each brake shoe facing the inner surface of the brake drum. A controlling lever is disposed at the top of the speed reducer corresponding to the free ends of the brake shoes. One end of the controlling lever is connected to an end of a fixing resilient member. The other end of the fixing resilient member is connected to a moving iron of a first solenoid. A clasping block is connected to the moving iron of the first solenoid. The other end of the controlling lever is connected to a moving iron of a second solenoid.

Abstract: A brake structure for a roll-up door includes a brake drum fixed to a transmission shaft of a speed reducer. The brake drum receives a pair of brake shoes in opposite inner sides thereof. The brake shoes are pivotably connected to each other at an end of each brake shoe. A linking resilient member is connected between the free ends of the brake shoes. A brake pad is attached to a surface of each brake shoe facing the inner surface of the brake drum. A controlling lever is disposed at the top of the speed reducer corresponding to the free ends of the brake shoes. One end of the controlling lever is connected to an end of a fixing resilient member. The other end of the fixing resilient member is connected to a moving iron of a first solenoid. A clasping block is connected to the moving iron of the first solenoid. The other end of the controlling lever is connected to a moving iron of a second solenoid.

Abstract: A delayed closing mechanism for a rolling fire door is provided wherein an AC solenoid having its sliding rod pivoted to one end of a connecting rod which is also pivoted at a central portion while the other end of the connecting rod is pivoted to the lower end of a spring biased actuation rod, a recess is provided on a side of the actuation rod to form a shoulder, the upper end of a latch rod pivoted at its central portion swings into the recess of the actuation rod and its lower end is acted on through a DC solenoid which can be controlled by an operator or activated through the discharge from a capacitor in the event power is cut off, the DC solenoid sliding rod is activated to swing the latch rod to move away from its position blocking the actuation rod, and cutting off power to the AC solenoid. The spring biased actuation rod pushes the braking rod in the braking device to pivot and thereby release the brake so as to permit the door to open or close.