Patent attributes
A door mechanism includes a bracket and a door shaft, rotationally mounted to the bracket, to operate a door. The door mechanism includes a gear assembly having a ring gear, set of planetary gears, sun gear, and drive sprocket. The ring gear fixed to the door shaft. The door mechanism includes a holding brake to counter the closing bias of the door. The door release has an engaged position in which rotation of the door shaft in the second direction is impeded by a first brake; and a disengaged position in which rotation of the door shaft in the second direction is unimpeded by the first brake. The door mechanism includes a link and a second brake. The link is configured to melt in response to a predetermined temperature. The second brake is configured to provide resistance in response to component rotation exceeding a predetermined speed.