Introduction to Screw Hoists
A screw hoist, also known as a screw-type hoist, is a mechanical device that uses a threaded rod to connect directly or through guide sliders and connecting rods to the gate leaf, enabling the gate to be opened or closed by the upward and downward movement of the screw. With the widespread development of water conservancy and hydropower projects, hoists and gates are extensively used in projects such as reservoir irrigation areas, river embankments, and hydropower stations. The installation, debugging techniques, and knowledge of usage and maintenance should be vigorously promoted. It is essential to disseminate this technology and knowledge among construction and installation units as well as operation and management departments to ensure project quality and maximize project benefits. Before installation, it is necessary to check whether all parts are in good condition, whether lubrication is sufficient, whether bolts are loose, and whether the relevant technical data are consistent.
The screw axis must be perpendicular to the horizontal plane of the crossbeam on the gate platform and align vertically with the gate lifting lug hole to avoid tilting of the screw, which could cause localized stress and damage components.
After installation, trial operation must be conducted. First, perform a no-load test by moving the screw through two strokes to listen for any abnormal sounds and check whether the installation meets technical requirements. Second, perform a load test under rated load by moving the screw through two strokes to observe the operation of the screw and the gate for any abnormal phenomena. Only after confirming that everything is correct can formal operation begin. After operating under load for a period, perform the first maintenance by cleaning off metal particles generated from the friction of new components, especially the screw, nut, worm, and worm wheel. Apply lubricant, ensure tight sealing, and continue use. Operators must understand the structure, performance, and operation methods of the hoist and possess certain mechanical knowledge to ensure the normal operation of the machine.
Before operation, conduct a comprehensive inspection of the hoist, checking whether lubrication is adequate in all parts and whether bolts are loose. For electric operation, check whether the power circuit is connected and whether the switch is in good condition.