| 摘要 |
Perforating equipment (111) for high speed transversal perforations of variable lengths on a continuous form (32) in movement is disclosed. The perforations are carried out by means of a perforating blade (39a) against a projecting profile (41a) of a blade contrast (39a) and blade and contrast servomechanisms (43, 128) for rotating a support for the blade and the blade contrast. The projecting profile (41a) has sectors with axial extensions different in dependence on their angular positions. The contrast servomechanism (128) is settable for selecting an angular phase of the blade contrast (39a), such to positioning, for the contrast with the blade, a sector of the projecting profile (41a) having axial extension equal to the requested length of the perforation (P). The blade contrast can be constituted by a hollow cylinder (113) rotatable around a support shaft (114) as a radial air bearing of pneumostatic type. |
