| 摘要 |
A lifting system for elongated objects comprises a rack and pinion driven lift surface, on which said object is placed. A work platform having a centre opening is provided above the lifting surface in such a way that said object may be brought through said centre opening up to a suitable level. The work platform (50) comprises two main elements, a stationary outer platform part (51) and an inner movable platform part (52). The inner platform part (52) is comprised by a number of triangular segments (54) each rotatable about a respective vertical pivot axis (60). The inner portions of said triangular segments (54) define the centre opening of the movable platform part (52) and all of the triangular segments (54) are driven by means of arcuate gear segments (64), one gear segment being provided on the under side of each triangular segment (54) and being engaged with a respective pinion (63). The rotary movements of all the triangular segments (54) are synchronized in that all pinions (63) are interconnected through synchronizing gear wheel (68, 69) so that all said triangular segments (54) will move in synchronism the same angle. Thus, the size of said centre opening, defined by said inner portions of said triangular segments (54) may be continuously adjusted. |
