| 摘要 |
<p>The knife (18) consists of a concentrically positioned primary blade (1) (with an overall height (H)) and two adjacent supplementary external blades (17) arranged alongside. These have a lesser height (h) and a thickness (e) which is double the thickness (d) of the primary knife blade. The number of blades in the perforating knife can be altered to suit the requirement of a particular use. The knife blade (1) has teeth on one side which work against a counter perforation cylinder. The knife blades can all be removed and exchanged by other combinations of knives. The thickness (D) of the perforation knife is constant and is formed by the combination of the primary knife blade and the supplementary blades. Whatever combination of blades is used, he overall thickness is always twice the thickness of the supplementary blades plus the thickness of the primary blade.</p> |
