| 摘要 |
PURPOSE: A lifter is provided to prevent articles and projectors from falling during lifting up and down and to promote reduction in manufacturing cost. CONSTITUTION: A main shaft(510) rotates as a motor(200) operates in a specific direction. A band type rope coiled on the central outer circumference of the main shaft(510) is released and a main case descends thereby. The main case(100) does not descend in a perpendicular direction of its movement by contact between guide bars on the four edges of the main case and a guide rail on the ceiling. A spring(620) on the outer circumference of a sub-shaft(610) is already distorted by rotation of the main shaft(510) and influenced by a force for reverse rotation. Therefore, the load of the main case and a projector is supported through the distortion force. |
