| 摘要 |
A display lifting device which is mounted within a ceiling plenum and is arranged for concealing a support framework, lifting arm and display within the ceiling area. A support arm for the display is pivotally mounted within the framework and is biased in the downward position and supported by a cable mounted on a cable drum drivingly connected to a reversible motor. The support arm comprises at least two telescoping sections with the cable connected to the end of the inner lower most section so that as the cable is extended the arm pivots downward with the telescoping sections extending through gravity to their fullest extent. In this way, the display can extend a considerable distance from the ceiling for viewing by the audience while in the retracted position a very small opening and space within the plenum is required for concealment. Mechanical stops and limit switches are provided at both extremes of the movement of the display and support arm to restrict the angular movement of the arm. A cover matching the opening in the ceiling is attached to the support arm and is pivoted from the ceiling to close the ceiling opening when the arm is raised into the upper concealed position. Actuation of the display lifting device can be made with a wired control panel or a remote control device.
|
