Abstract: A mechanism for controlling the raising and lowering of a door comprising a speed reduction gearing, a high speed input shaft and a low speed output shaft connected to the gearing, and a governor mounted on the input shaft for regulating the input shaft's rotational speed. More particularly, the mechanism is provided with a brake having a movable brake shoe, a temperature sensitive link and an elongate member having a central portion coupled to the brake shoe. As well, the first portion of the elongate member is engageable with the temperature sensitive element and a second portion of the elongate member is engageable with the actuator. In this way, the elongate member is provided for moving the brake shoe to the release position in response to one of (1) the temperature sensitive link upon the temperature reaching a predetermined temperature and (2) the actuator.

Abstract: A mechanism for controlling the raising and lowering of a door comprises a speed reduction gearing, a high speed input shaft and a low speed output shaft connected to the gearing, a governor mounted on the input shaft for regulating the input shaft's rotational speed whereby also regulating the output shaft's rotational speed, a first mechanism for operatively connecting the input shaft to a second mechanism for rotating the input shaft, a mechanism for operatively connecting the output shaft to a slatted retractable door, a brake for preventing rotation of the output shaft, and a release-mechanism the brake to permit rotation of the output shaft.