| 摘要 |
<p>In the rotary punching of a moving material web, the punched out waste material has to be removed so as not to interfere with the course of the punching. This can be done with a vacuum and internal ducts in the female roll, but this method cannot be used at high working speeds because of centrifugal force. Instead of this in accordance with the invention, the die hole of the female roll is provided with pistons that are maneuvered to and fro in rhythm with the rotation of the roll. As a result, the punching waste is retained for only a short while after the punching, and then is ejected and carried away via an external suction arrangement.</p> |
