| 摘要 |
PROBLEM TO BE SOLVED: To provide a crane load derivation device capable of achieving load display without giving discomfort.SOLUTION: A load derivation device 40 derives a first tension value of a relief rope 28 on the basis of a load value detected by a load detector 42, and comprises a load arithmetic device 50 for performing correction for reducing error caused by rotation resistance of sheaves 18, 20a, 22a included in the derived first tension value and determining suspension load on the basis of a second tension value which is the corrected first tension value. The load arithmetic device 50 corrects the first tension value using a correction factor corresponding to a movement direction of the relief rope 28, and in a transient period until the rotation resistance of the sheaves 18, 20a, 22a become constant during taking up and down of a boom 6, gradually changes the correction factor so that a correction mode between increase correction for increasing the first tension value and reduction correction for reducing the first tension value is transited according to increase of an accumulation rotation pulse number of a drum 26a. |
