minus screw meaning in Chinese

一字槽头螺钉

The equijpment is improved in design and is made into a fully automatic h - beam assembling machine referred to the same foreign sort of products . the positioning of the flange and web is performed through hte plus and minus screw mandrel drivenby the mtr accurately . and there is a highly precise coder to feedb - ack and show the accurate size on the unit set to guarantee the flanges , the webs with different width different width within the specified range for accurate positioning and automatic alignmet . there is no need to make adjustment each time
该机是本厂参考国外同类产品基础上改进设计而成的全自动h型钢组立设备，其腹板翼板定位采用电机精确带动正反丝杆夹紧，另一侧设有小行程液压夹紧，能确保规定范围内的不同宽窄的腹板，翼板精确定位，自动对中准确，无须每次作调准。