| 摘要 |
A safety device for a hydraulic working machine having control valves (22-24)for controlling flows of pressurized oil from a hydraulic pressure source (21) to hydraulic actuators (15-17), electric lever devices (51-53) for outputting operation signals (v51-v53) according to lever operation, electromagnetic proportional valves (25-30) for outputting control pressures for controlling the control valves (22-24), a pressure calculation section (50) for calculating control pressures (P25-P30) according to the operation signals (v51-v53), a control section (50) for controlling the electromagnetic proportional valves (25-30) so that control pressures outputted from the electromagnetic proportional valves (25-30) are the calculated control pressures (P25-P30), high-pressure selection circuits (41-44) for selecting a high-pressure side pressure of the control pressures outputted from the electromagnetic proportional valves (25-30), pressure detectors (45, 46) for detecting the control pressure selected by the high-pressure selection circuits (41-44), an abnormality determination section (50) for determining an abnormality of the electromagnetic proportional valves (25-30) based on the control pressure detected by the pressure detectors (45, 46) and on the control pressure calculated by the pressure calculation section, and prohibition devices (47, 48) for prohibiting control operation of the control valves (22-24) when it is determined that there is an abnormality in the electromagnetic proportional valves (25-30). |
