| 摘要 |
A pallet elevator for a ship includes symmetrical carrier trays and symmetrical followers, each follower being pivotally mounted at its center on a tray-carrying chain. A pair of follower rollers are symmetrically mounted on each follower, one roller of the pair being mounted at each end thereof. The center line of each carrier tray is coincident with the center of each of its respective followers and the center plane of the tray is perpendicular to a line joining the centers of the follower rollers. The follower rollers are guided by a guide track which comprises a single race adjacent the load-carrying flight of the chain and a pair of parallel races adjacent the return flight of the chain. The track further comprises a pair of outer cam tracks for guiding the rollers adjacent the sprockets around which the chains pass. The outer cam tracks merge the single race and the parallel races along generally arcuate paths. When the follower rollers are guided in the single race they are positioned substantially vertically one above the other. The carrier tray is then in a horizontal position. When the follower rollers are guided in the pair of parallel races, on the return flight of the chain, their centers are positioned substantially horizontally and the carrier tray is in a generally vertical position. The outer cam tracks guide the follower rollers by means of slots following arcuate paths which slots rotate each carrier tray ninety degrees as its followers are guided from the single race adjacent the load-carrying flight of the chain to the parallel races adjacent the return flight of the chain and vice versa.
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