| 摘要 |
An apparatus for raising and lowering a windable, portable motion picture screen which has a sliding pole inserted into a vertical opening within a hollow support cylinder in such a way that the sliding pole can slide up and down within the cylinder. A lever member is provided on the upper portion of the supporting cylinder to force against the sliding pole within the cylinder and hold it in position. The sliding pole is provided with a rack portion on one side thereof and rack and pinion gear drive means are connected to the side of the supporting cylinder in such a manner that they engage the rack portion of the sliding pole to move it up and down within the supporting cylinder as the gears are rotated. |
