| 摘要 |
The monitor (29) with a flat screen liquid-crystal display (35) mounted in a frame (11) which is placed in an upper compartment of passanger aircraft cabin, comprises a d.c. motor (19) which is mounted so to revolve the monitor through an arc between the position of retraction when the monitor is inside the frame, and the position of deployment when the monitor is open for observation. The motor shaft can rotate in two opposite directions, which is determined by a control circuit (13) connected to sources of positive and negative voltages. A fly-wheel (21) is mounted on the shaft of motor for storing the rotational energy, which is used for retracting the monitor when required. The control circuit (13) is connected so to detect a breakdown of electrical power supply at the mains and to apply a pulse to the motor for retraction. The crankcase of motor is mounted directly on the frame, and the shaft of motor is mounted directly on the flat-screen monitor, or the motor is mounted on the monitor, and the motor shaft is mounted directly on the frame. An electromagnetic lock (31) is used for maintaining the monitor in the rectracted position, and an interrupter of deployment position (17) is used for stopping the motor when the monitor is in the position for observation. The control circuit (13) applies a pulse of negative voltage each time a breakdown of power supply is imminent, in order to retract the monitor before the power cut. |
