LOAD MEASURING DEVICE FOR CONSTRUCTION MACHINE

摘要

PROBLEM TO BE SOLVED: To reduce leaning of static friction force generated between a cylinder tube of a boom cylinder and a piston rod on one side to measure load with high precision. SOLUTION: This load measuring device for the construction machine is provided with proportional solenoid valves 34, 35 provided between a direction control valve 22 for controlling flow of pressure oil for driving the boom cylinder 5 and a pilot pump being an oil pressure source of pilot pressure for operating the direction control valve. A controller 40 is set to control the proportional solenoid valves 34, 35 so that the boom cylinder 5 vibrates minutely by supplying pressure oil into a bottom side oil chamber 5c and a rod side oil chamber 5d of the boom cylinder 5 alternately to such extent that the boom cylinder 5 is not extended or contracted before computation for calculating holding force is performed when an order for measuring weight of a load 60 by operating a measurement ordering switch 41 manually is given to the controller 40. COPYRIGHT: (C)2007,JPO&INPIT