Unidirectional centrifugal mechanism of door operator

A door operator for a fireproof and smoke prevention rolling door provided with a door curtain configured to slide down to close during a fire accident and to be lifted up to open by manual operation, the door operator comprising:

• a rotary shaft provided in a housing, the rotary shaft including a plurality of slots equally spaced from each other and disposed circumferentially at a first end and an output shaft at a second end opposite of the first end of the rotary shaft;
• a centrifugal brake mechanism arranged to retard the falling speed of the door curtain within a predetermined safety range, when the door curtain slides down to close in a unidirection;
• and
• a unidirectional mechanism arranged to control the falling speed of the door curtain only in a unidirection,
• wherein the centrifugal brake mechanism includes an end disc, a pair of stationary pins, and a pair of brake pads, the end disc is rotatably mounted on the first end of the rotary shaft, the end disc has a first end face and a second end face opposite to the first end face, a shaft hub extends from the first end face of the end disc and has a radial mounting hole extending radially toward the plurality of slots;
• the pair of stationary pins extend from the second end face of the end disc;
• the pair of brake pads are pivoted on the end disc by the pair of stationary pins, respectively, so that each of the pair of brake pads is capable of being swung and abutted on an inner wall of the housing when the centrifugal brake mechanism is rotated together with the rotary shaft;
• wherein the unidirectional mechanism includes a base, an active pin and an elastic element, the base is disposed on the shaft hub and located outside the mounting hole, the base includes a limiting slot;
• one end of the active pin is provided with a unidirectional latching tooth, the active pin is slidably disposed in the mounting hole in such a manner that the other end of the active pin extends through the base and protrudes from the base;
• the other end of the active pin is provided with a draw bar;
• the elastic element is accommodated in the mounting hole and configured to surround the active pin;
• the elastic element is compressed and located between the unidirectional latching tooth and the base so that the active pin is biased by the elastic element and that the latching tooth is biased toward the plurality of slots when the draw bar is received in the limiting slot.