| 摘要 |
<p>Sheet material is converted to cushioning material, for packaging, by rolling the edges of the running sheet, e.g. of paper plies, towards the centre of the sheet, to form a 3-D cushioning strip, and then weakening the strip to provide transverse tear lines enabling lengths of strip to be readily detached. The strip may be weakened by a serrated bar reciprocated against a stationary serrated bar (Fig. 3, not shown), or by serrated blades rotating on parallel shafts (Fig. 9, not shown). The machine may include means to tear the strip at the serrations. Alternatively, the strip may be weakened by a chemical, electromagnetic or radiation device, e.g. a laser. The sheet material may be perforated before conversion.</p> |
