| 摘要 |
A multilevel speed regulation method for a jack and a multilevel speed regulation jack use a hydraulic speed regulation line which includes at least two parallel hydraulic sub-lines extending between the input and output cylinders and the pressure applied by the output cylinder against the load is taken as the control signal to control the opening and closure of the hydraulic sub-lines or their combination at different speed levels. Application of the method in this invention provides the jack with the capability to automatically transfer between different speed levels in the case of different loads, and thus the lifting efficiency is improved. Additionally, this invention also provides a multilevel speed regulation jack, in which a hydraulic speed regulation line of at least three speed levels is connected in series between the input and output cylinders. This hydraulic speed regulation line consists of at least two parallel hydraulic sub-lines. The jack in this invention is capable of transferring between different lifting speeds, and thus the lifting efficiency of the jack is enhanced.
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