METHOD FOR DETECTING EXCAVATION DEPTH OF EXCAVATING MACHINE

PURPOSE:To detect an excavation depth of an excavating machine by detecting the rise of driving pressure arising when the excavating device leaves the ground thereby determining the start of lifting of excavating device, and detecting the completion of lift from the variation of load acting on the pulley. CONSTITUTION:A wire rope 4 is wound and an excavating device 6 is lifted by rotating a winch drum 5 using a hydraulic motor 12. When the excavating device is lifted, the driving pressure of hydraulic motor is increased, from which the start of lifting is detected. When the excavating device 6 reaches the position of lift completion, a detector 13 is activated to count total number of revolutions N of winch drum 5. Then, the length of rope wire 4 wound up, the height of excavating device tip above the ground, and the excavation depth are determined. Thus, the brake for winch drum can be operated without the delay of timing by grasping the time when the excavating device drops.