It is a long-standing issue that hydraulic jacks should not be overloaded. If hydraulic jacks are used, this point should be taken seriously. Hydraulic jacks are not suitable for long-term high load conditions, while screw jacks can be under high pressure for a long time, which is clearly reflected in bridge support.

The characteristics of hydraulic jacks are simple operation, fast return, and high efficiency. But the load difference is its weakness. This is related to its safety factor. Firstly, we need to understand the concept of a safety factor, which means that the theoretical force that the load-bearing part can bear must be greater than the actual force it can bear, that is, the ratio of the ultimate stress to the allowable stress. The ratio of the two is called the safety factor.

The safety factor of the hydraulic cylinder design is set to ≥ 5, which results in a large volume and high cost of the hydraulic cylinder, making it difficult to compete with foreign companies in the international market. Through experimental calculations, the safety factor of the jack cylinder design can be set at 1.4-1.6, and after actual use, it has been proven that the selection of this safety factor is reasonable.

A safety factor of 1.4-1.6 is not considered excellent compared to screw jacks. Hydraulic jacks are more like functional products compared to screw jacks, but they are sufficient for use in many occasions such as workshops and auto repairs. As long as the rated load of the hydraulic jack is paid attention to, it can perform well in the long run.