The jack cannot be overloaded, and the lifting height should not exceed 3/4 of the total height of the threaded rod or piston to avoid fully pushing out the sleeve or piston, which may cause damage to the jack and cause accidents. The jack should be lifted vertically, and the bottom pad should be flat and firm. If the jack deviates during the lifting process, it must be loosened and re lifted. After the object is raised to a certain height, a safety sleeper should be placed underneath it, To prevent the danger of sudden piston drop caused by tilting or oil return of the jack; When lowering the hydraulic jack, the throttle should be slightly opened and not suddenly lowered to avoid damaging the internal cup.

        The wear rate of the jack thread should be less than 20%; The automatic device must be in good condition; New or overhauled jacks should undergo a 10 minute static test at 125 times the allowable working load and a dynamic test at 11 times the allowable working load; And check for unnecessary cracks and significant local deformation phenomena, generally testing once a year.