worm screw lift; Safely self locking, Positioning Precision, Heavy Duty, Uniform Lifting Speed, Low Efficiency, Use Infrequentl worm screw liftConfiguration: Worm Gear, Worm Shaft ... , Taper Roll Bearings, Seals, Housing, Self-locking Trapezoidal Screw,etc.* Model: RN-0.5ton, RN-1 ton, RN-2 ... ,Construction, Irrigation,Chemical industry,Health Care,Culture,Health,etc worm screw lift