The threaded rod of a screw hoist is directly connected to the gate leaf or through guide blocks and connecting rods. The mechanical system (Figure 1) operates by moving the screw up and down to open or close the gate. The screw is supported within a load-bearing nut, which along with the transmission mechanism (bevel gear transmission or worm gear transmission), is fixed on the support frame. By activating the power source or using a manual crank handle, the transmission mechanism is driven, rotating the load-bearing nut and causing the screw to move up or down, thereby opening or closing the gate. The screw functions as a member under compression or tension; when a downward force is required to lower the gate, the stability of the compressed rod must be calculated. Screw hoists have a simple structure, are robust and durable, and are cost-effective, making them suitable for small plane gates and radial gates, with their operating force generally below 200kN. High-capacity screw hoists with capacities of 500kN and 750kN have also been produced, used for the operation of plane gates and radial gates in submersible holes.