Screw jack can lift heavy objects only by shaking the handle manually, and can also support heavy objects for a long time. It is a lifting tool with a wide range of applications. When using screw jacks, there are several precautions that users should pay attention to.

1. Avoid overloading. Before using the screw jack, the operator needs to estimate the weight of the heavy object and select the screw jack with matching tonnage according to the weight to avoid overload.

2. The jacking height shall not be too high. Generally, there is a mark line on the sleeve or piston of the screw jack. When using the screw jack, the jacking height shall not exceed the mark line, otherwise the piston may not be able to return, or even directly jack off the piston, resulting in accidents.

3. Cannot use more than one. If the user uses multiple screw jacks to lift a heavy object at the same time, the jacking speed is difficult to synchronize. At this time, the heavy object is likely to tilt and cause excessive pressure on some screw jacks.

In the process of using the screw jack, the user can ensure the safety of lifting operation as long as he follows the above precautions and standardized operation.