... steel hoisting level,vertical hoisting 2.Clamping force control by hydraulic 3.Load:RYY (6-12t),RYYL( 20-28t) High ... level down, can be complete hoisting level . 3.Clamping force controled by hydraulic,can adjust the size of clamping force , In ... mouth, ensure malfunction, can keep hydraulic cylinder pressure. 4. The hydraulic cylinder, valve body and hydraulic pump , according to user selecting ...