PURPOSE: To provide a falling-down prevention device for a truck crane in which a load detection device with a simple construction is compactly incorporated.
CONSTITUTION: A load detection device is set to a fixing side member 35 coupled with an earth side moving member 39 via an elastic body 40 so as to detect a load acting on the earth side moving member 39 based on the relative movement distance between both members 39, 35. For instance, plural coils 2a, 2b which are set on the fixing side member 35 of an outrigger portion, are connected in series, and are excited by an AC voltage, cores which are set on the earth side moving member 39 and oppositely face to the respective coils 2a, 2b, and a compression spring 40 which moves the respective coils 2a, 2b and the cores relatively just a distance proportional to the load F of an object to be detected are provided so that the total impedance of the whole coils is kept constant even if the respective coils 2a, 2b are relatively moved, and thus the load detection device is formed. The change ratios of the impedance of the respective coils 2a, 2b against temperature are to be equal, and the load is detected based on the output voltage of the connection point of the respective coils 2a, 2b.
INOUE KOJI
ISHII HIROYASU
OOTSUKA TATEYUKI
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