| 摘要 |
<p>A vertically extensible mechanism for controlling displacement of a panel structure such as an advertising sign, moves the structure between vertically spaced deployed and retracted positions. The mechanism comprises a pair of vertically oriented laterally spaced guide tracks each having two or more elongate track sections that are telescopically extensible. The panel structure is carried in a vertical orientation between the guide tracks which are anchored to a mounting to extend vertically thereon. The mounting can be an elevated one, e.g. in a roof structure, or in a building wall above a door opening, or a low level mounting, e.g. on a ground surface or floor.</p> |
