| 摘要 |
To provide for precise vertical movement without guide elements of a lifting frame, a main shaft (21) has a plurality of cam disks, such as eccenters (26) located thereon, which are coupled to the lifting frame, directly, or by means of double-arm levers. The eccenters may be placed 180 DEG offset from each other on the shaft, with one eccenter follower or cam follower (27) secured to the frame at a first longitudinal position, and other eccenters or cam followers (27) coupled to double-arm levers (33), pivotable about a fixed pivot axis (36) and having the remote ends coupled to the lifting frame (8) at a position remote from the first attachment position. Synchronous movement of the connections to the lifting frame (8) is ensured by using only one drive shaft, so the movement can be, precisely, up and down, while maintaining the frame horizontal.
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