一般在带钢连续作业线的头部,或者同时也在尾部设有活套装置,以保证在焊接钢卷头尾过程中机组不停止工作。活套的型式很多,有高架式、地坑式、水平式、隧道式等。旋转式自由活套是一种新的活套结构,它是美国威因联合公司(WeanUnited)设计的。已取得生产宽度323.81毫米(12 3/4时)及以上的旋转活套的许可证。其结构原理及型式见图。 Generally in the head of the strip continuous operation line, or at the same time there are looper set in the tail to ensure that the unit does not stop work in the process of welding the coil head and tail. Looper type many, there are elevated, pit type, horizontal, tunnel type and so on. The revolving free looper is a new looper structure designed by Wean United. A permit has been obtained for a revolving round with a production width of 323.81 mm (12 3/4 hrs.) And above. The principle of the structure and type see figure.