| 摘要 |
PROBLEM TO BE SOLVED: To provide a stroke control method of a hydraulic jack capable of restraining a deviation in a relative stroke value of a lowering quantity of the whole mutual hydraulic jacks for supporting a column of cutting and removing a lower end part, within an allowable value. SOLUTION: This stroke control method comprises an initial setting process of setting a zero point for detecting the relative stroke value of the respective hydraulic jacks in a state of lifting a rod up to a lower end level of the cut-removed column with every lowering process continuing with a cutting process after a jack setting process, and a stroke detecting process of detecting an absolute stroke value and the relative stroke value of the respective hydraulic jacks in a predetermined detection period based on the setting of the zero point up to finishing the lowering process on and after starting the lowering process of simultaneously lowering the rod of the hydraulic jacks, and controls a stroke of the hydraulic jacks of restraining the deviation between a lowering quantity of the hydraulic jack fastest in a lowering speed in the lowering process and a lowering quantity slowest in the lowering speed, within the allowable value, based on the detected relative stroke value. COPYRIGHT: (C)2010,JPO&INPIT
|
