... 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 ... Use Infrequently, Easy Installation, Low Noise.* Linear Motions: Elevating,Lowering,Pulling,Pressing,Pushing,Rolling.* Manual Operation and Electrical Operation are available.* Multiple Screw ...