| 摘要 |
The two-strip mast can be erected automatically with the air of a motor drive from a rolled-up state. A box-shaped base (6) is used in which are rollers (7,8) on which the strips are folled, and also drive rollers (9,10). As the strips are fed outwards, the drive rollers hold their cross-section straight and bring them to the pont where they interengage. The drive rollers are of rubber, or are rubber-coated, to provide efficient friction against the strips. The strips are arched in cross-section, and have flaps which are bent inwards to an extent that when the strip curvature is deformed transversally to a straight stage, they are angled outwards, disengaging from one another. When assembled, the seam between the two strips has a more crossways curvature on its two sides than that of the strips themselves. |
