Thermal release apparatus for coupling a damper actuator to a damper

Abstract

A thermal release coupler employed in a fire and smoke damper assembly, in which the fire and smoke damper assembly includes an array of damper blades carried in a damper frame, movable between open and closed positions, with a linkage joining the damper blades. A damper actuator operatively connected to the linkage drives the damper blade array between the open and closed positions. A drive coupler and a connecting coupler are formed from identical coupler units, carried respectively on a drive shaft from the actuator, and a connecting shaft that connects to the damper blade linkage. The connecting shaft is hollow and rotates on the drive shaft. Each coupler unit has a generally circular coupler body, with two connecting, circumferentially opposed ears. A drive post extends from one connecting ear, and a connecting post extends from the other ear. The two coupler units are oriented such that the drive post of each coupler unit extends toward the other coupler unit, and the coupler units are positioned such that their ends are coplanar A torsion spring, with legs attached to each coupler unit, is carried on the connecting shaft and extends between the drive coupler and the connecting coupler. A fusible link extends between the drive post and connecting post to maintain the connecting coupler connecting post in close proximity to the drive coupler drive post, separating at a rated temperature and allowing the spring to drive the damper array shut.