| 摘要 |
To advance a belt (10) stepwise without the necessity for a heavy tensioning roll towards the end of the return branch (19), a ram (58) is deflected to the left, as a result of which a first stepping roll (55) is moved into its position indicated by dashed lines and the loop (59) is extended in order to pull the leading end of this upper branch (13) into this loop (59). A movement in the opposite direction of the belt (10) is prevented by apparatuses operating in one direction, for example ratchet mechanisms (not shown), on the rolls (53, 54). At the same time, a second stepping roll (56) is moved into its position indicated by dashed lines, to reduce accordingly the extension of the loop (60), so that a part of the return branch (19) of the belt (10) can move back into the upper branch (13). The ram (58) is then deflected to the right, to return the rolls (55 and 56) to their original positions, the loop (59) being reduced and the loop (60) being extended. <IMAGE>
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