| 摘要 |
PROBLEM TO BE SOLVED: To provide an overload preventing device stopping actuation of a boom or the like even if an abnormality occurs in an automatic stopping means for stopping the actuation of the boom or the like, by surely energizing the solenoid of a solenoid selector valve. SOLUTION: An output selecting means 31 for receiving a stop command output from a controller 23 is interposed between the controller 23 and a main output means 32 outputting an excitation voltage for exciting the solenoid 13 of the solenoid selector valve. An auxiliary output means 34 is provided for exciting, on receiving the stop command via the output selecting means 31, an auxiliary solenoid 14 provided at the solenoid selector valve. The stop command output from the controller 23 is compared with an output of the main output means 32, and when they are not coincident, the output selecting means 31 is switched to the auxiliary output means 34, so that even if the main output means 32 has an abnormality, the auxiliary solenoid 14 of the solenoid selector valve can be excited by the auxiliary output means 34.
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