... easy operation, convenient maintenance.2.Low speed, low frequency:Be suitable for heavy load, low speed, low service frequency.3.Self-lock: Trapezoid screw ... pushing,pulling and rolling movements2.High efficiency,high speed,low loading,frequently use,high accuracy,long life3..Arrangement: ... Industries:Our SWL series screw jacks are widely used in the industries such as metallurgy,mining,hoisting ...