| 摘要 |
Foldable link rod system to be placed on a travelling frame comprises pivotally suspended link rods (16, 18) for raising and lowering an operation platform (14). A rotating stool (20) constitutes the connection between two link rods (16 and 18) which are placed in continuation to each other. The one part of the rotating stool (20) is linked to the free end of the first link rod (16) which at its opposite end is pivotally linked to a swinging rod system (26, 28, 30, 32). The second link rod (18) is linked to the other part of the rotating stool and at its other end it is linked to the operation platform (14). The two link rods are pivotal by means of each of their swinging devices (54-70) which are supported on the travelling frame (10, 12) and the rotating stool (20), respectively. The swinging rod system (26, 28, 30, 32) is adapted to communicate a swinging movement to the first link rod (16), the free end of which follows or yet is close to a leadline intersecting this end in one of the end positions of the link rod. At the same time, the rotating stool (20) of the swinging rod system (26, 28, 30, 32) is kept in a mainly horizontal position.
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