| 摘要 |
<p>A rotary shear machine is described having a plurality of oppositely rotating hollow cylinder pairs carrying helical blades for transversely shearing several continuously moving webs perpendicular to their directions of travel. Each cylinder pair includes a separate reversible DC motor drive and an electronic digital control system regulating the motor drive for cutting sheets of predetermined lengths from the respective webs. A unique feature of the machine is a web feed and pull roller system having an independent drive for engaging and feeding the continuously moving webs into the respective helical blade shears and pulling sheets from the respective shears as they are cut from the continuously moving webs. The upstream feed roller system includes means for sensing web velocity and generating electronic pulses for input into the control means regulating the respective reversible DC motor drives driving the respective helical blade shears. The feed roller system further includes means for continuously generating electronic pulses even though the velocity sensing component is not in contact with the moving web. The proximity of the web velocity sensing means to the helical blade shears enables the helical blades to sever sheets from the respective webs with a high degree of precision and uniformity.</p> |
