THE CONTROL METHOD AND DEVICE OF A HYDRAULIC APPARATUS WHOSE CYLINDER IS ABLE TO COME TO A DESIRED WORK POSITION ITERATIVELY

摘要

The control method of a hydraulic apparatus whose cylinder is able to come to a desired work position iteratively uses hydraulic control members which control a high-pressure accumulator communicated to the chamber with piston-rod of a hydraulic cylinder and a low-pressure accumulator communicated with the chamber without piston-rod of said hydraulic cylinder respectively to accumulate the energy in different grades, such that said hydraulic apparatus can lift said hydraulic cylinder to a desired work position automatically and iteratively when it is in nonload and startup state. In unload state, oil in said chamber without piston-rod enters said high-pressure accumulator; in normal state, oil in said chamber without piston-rod is introduced into said low-pressure accumulator in order to be used as the energy source of driving the cylinder to desired work positions in nonload state for the next work operation. The present invention overcomes the drawback of oil leakage from the vent port of the oil tank in the prior art, and has a simple hydraulic circuit structure, good seal, and accurate & reliable operation. Furthermore, because of accumulating the energy in different grades, convenient operation, good ordinate control, long work stroke and being able to come to the desired work position iteratively and automatically, the invention not only improves the work efficiency and the apparatus's life, but also reduces the workload of the operator.