| 摘要 |
Web, drawn intermittently from roll A, e.g. by packaging apparatus D, is formed into a U-shape in suction device C, which includes a loop sensor 3a controlling a device i which feeds web to device C. The vertical extent of the U-shape is thus kept constant and web tension downstream of device G is controlled. Device C comprises a rectangular-section, open-topped box, suction being applied at port 2b. The distance between the box side walls, i.e. those which extend parallel with the web, is adjustable to match the width of the web. The packaging apparatus is stopped when a second loop sensor 3b detects an abnormally small U-shape. <IMAGE> |
