The hand-operated hoist, also known as a manual screw hoist, is a type of equipment used for operating plane gates by human power. It features a self-locking function that allows the gate to stay in any position. Additionally, it comes equipped with anti-theft nozzles and specialized wrenches to prevent unauthorized water usage. The screw hoist boasts advantages such as quick directional speed changes, easy manual start-up, light operation, and flexible opening/closing functions. Its structure consists of a machine shell, cover, bracket, nut, screw, large and small bevel gears, thrust bearings, and a hand crank.
Manual screw hoists mainly include: LQ hand-cranked screw hoist (3T-100T), LQ hand-electric screw hoist (3T-100T), LQ side-cranked screw hoist (0.3T-5T), LQ hand-pushed screw hoist (0.3T-2T), and LQ hand-levered screw hoist (1.3T-2T). This series of products are designed reasonably, simple and flexible to operate, easy to install, suitable for use in both plains and mountainous areas whether there is electricity or not, and feature water theft prevention functions, ensuring safety and reliability. They are primarily used in hydropower, municipal construction, water supply and drainage, aquaculture, agricultural water conservancy projects, etc.
Installation steps for screw hoists:
1. When installing a screw hoist, ensure the base foundation layout plane is level at 180 degrees; the contact area between the hoist base and the foundation layout plane should reach over 90%; the screw axis must be perpendicular to the horizontal plane of the gate table; it should align vertically with the gate lifting ear hole to avoid screw tilting, which could cause localized stress and damage components.
2. Place the manual screw hoist in the installation position. Slide one limit disc onto the screw. Insert the screw from the bottom of the crossbeam into the machine until it protrudes from the top, then slide on another limit disc. Connect the lower end of the screw to the gate.
3. The foundation for installing the hoist must be stable and secure. The concrete for the machine seat and foundation components should be poured according to the specifications on the drawings. Do not remove or alter the temporary supports of the hoist before the concrete strength reaches the design strength, nor should you perform trial adjustments or test runs.
4. During installation, align the center based on the gate lifting centerline so that the longitudinal and transverse centerline deviations do not exceed ±3mm, and height deviation does not exceed ±5mm. Then pour the second phase of concrete or connect with the embedded steel plate.
5. Electrical equipment installation must comply with the provisions on the drawings and in the instruction manual, ensuring all electrical equipment is reliably grounded.
6. After installation, clean the machine, repair any damaged protective paint, and fill with lubricating grease.
Screw Hoist Debugging Methods and Precautions:
1. When the hoist is under no load, ensure the imbalance of three-phase current does not exceed ±10%, and measure the current value.
2. For upper and lower limit adjustments: when the gate is fully closed, press the upper limit against the upper travel switch and fix it on the screw of the screw hoist. When the gate is fully open, press the lower limit disc against the lower travel switch and fix it on the screw.
3. Adjusting the main command controller of the hoist must ensure the error in the gate rising and lowering to the upper and lower limits does not exceed 1cm.
4. After installation, a trial run must be conducted. First, perform a no-load test, allowing the screw to make two trips, listening for any abnormal sounds, and checking if the installation meets technical requirements.