| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a safety device of a working machine with a telescopic boom capable of determination even if relief pressure varies with oil temperature when, in order to determine whether or not a support force detection means 9 properly detects support force of a derricking cylinder 5 supporting the telescopic boom 4, a determination means S9 determines whether or not an output value detected by the support force detection means is within a predetermined range based on a preset reference value by operating the derricking cylinder to take down the telescopic boom in a state that the telescopic boom is placed on a boom rest 6 and by operating a relief valve arranged in a hydraulic circuit of the derricking cylinder to the relief pressure. <P>SOLUTION: The safety device is provided with a relief pressure detection means 19 for detecting the relief pressure of the relief valve and comprises a correction means S8 for correcting the output value detected by the support force detection means or the reference value according to the pressure detected by the relief pressure detection means. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
