| 摘要 |
PURPOSE:To prevent a sheet from being loosened with a simple construction, by utilizing the centrifugal force acted upon a weight according to the rotating motion of a drum when pulling the rear end of the sheet. CONSTITUTION:A drum 2 is so arranged that its rotational speed increases when a retaining roller 22 drops down into a sunk hollow part 20 to support the rear end part of a sheet. If the drum 2 becomes rotating at a high speed, the centrifugal force acted upon a weight 35 overcomes the tension of a spring 39 to shift the weight 35 to a position as shown by a chain line. The shifting motion of said weight causes a tension roller 32 to make a turning motion clockwise through a lever 34. Accordingly, a sheet S is tightened by the turning motion of the tension roller 32 while being put between the retaining roller 22 and the tension roller 32, thus to eliminate the loosening of a sheet during the rotating motion of the drum 2. |
