Abstract: A door operator having a fluid drive motor and a manual override. The bidirectional hydraulic motor connects to a drive shaft through a power train including a shiftable --quill--type manual clutch mechanism which allows an alternate connection of the drive shaft to a manually-operated wheel. When the cable which shifts the clutch for manual drive is pulled, a switch disables the control for the hydraulic motor. When the motor is not provided with pressured fluid from the pump a hydraulic brake engages the motor.

Abstract: This disclosure relates to an access door assembly for a ceiling. The assembly includes a frame adapted to be attached to supports of the ceiling and mounted in a generally horizontal position, and a door which fits within and has one edge hingedly connected to the frame. The hinge enables the door to swing between a generally horizontal closed position within the frame and a lowered open position. A constant-force return spring urges the door to the closed position, and an automatically engageable lock is provided for holding the door in the closed position. The frame and the door have closely adjacent Z-shaped frame members and the door is made of heat-resistant material, to form a fire retardant construction.