| 摘要 |
A method of and apparatus for guiding an elongate sheet of packaging material towards a former which manipulates the sheet into a tube having its longitudinal edges slightly overlapped to enable them to be formed into a seam, the sheet being caused initially to drift sideways in one direction as it is drawn towards the former, a detector being provided for detecting when one longitudinal edge of the sheet has drifted to a first predetermined position, the sheet then being caused to drift sideways in the opposite direction until the said one longitudinal edge of the sheet has drifted to a second predetermined position after which the sheet is caused to drift sideways again in the said one direction.
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