| 摘要 |
PROBLEM TO BE SOLVED: To prevent a carrying belt from being displaced or coming off from a pulley during operation.SOLUTION: A first belt supporting part supports a first carrying belt wound around each pulley rotatably in one rotational direction, while a second belt supporting part supports a second carrying belt, which is wound around each pulley to be extended and stretched longer than its natural length, rotatably in the other rotational direction. Further, a predetermined part of the second carrying belt moves between a first position to be displaced by being pressed against an opposed part on the first carrying belt and a second position to return the pressing against the opposed part on the first carrying belt by the predetermined part of the second carrying belt, and when the second belt supporting part moves to the second position, a displacement part displaces the part except the opposed part on the first carrying belt. Thus, when the second belt supporting part moves to the second position, the first carrying belt can be extended and stretched longer than the natural length, so that the carrying belt can be prevented from being displaced or coming off from the pulley during operation. |
