| 摘要 |
PROBLEM TO BE SOLVED: To exactly calculate hanging load and secure safety by judging an operating state of an attachment from a change at each detection tip and interrupting a new calculation by holding arithmetic values of hanging load calculated till the time when the attachment becomes a stoppage state for prescribed time or more. SOLUTION: An operating state of an attachment 10 is monitored by booms by angle sensors 17, 18 and changes in arm anglesθ1,θ2. When movement of the attachment 10 is stopped, the time elapsed after the stoppage is measured by a timer and whether the stoppage state is continued for prescribed time or more or not is judged. When the attachment 10 is moving in the vertical direction and the stoppage time is less than the prescribed time, hanging load Wx is calculated. When the attachment 10 is in the stoppage state for the prescribed time or more, bottom pressure P1 of a boom cylinder 12 is lowered by the time elapsed after the stoppage and a possibility that hanging load can not be exactly calculated exists. Therefore, arithmetic values of hanging load calculated till the time are held and a new calculation is interrupted, and if hanging load should exceeds rated load, an alarm is given.
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