To prevent a situation which a work bench is in contact with a boom or the like when a boom is in a housed state, and they are broken.
This device is provided with a leveling cylinder 55 for swinging the work bench 40 in upper and lower surfaces, a work bench inclining angle detecting means (a derricking angle detector 41, a work bench inclination detector 75, and a work bench inclining angle calculator 64 of a controller 60) for detecting an inclining angle of the work bench 40, a leveling cylinder control part 63 of the controller 60 for controlling operation of the leveling cylinder 55 so that the inclining angle of the work bench 40 detected by the work bench inclining angle detecting means is a predetermined angle (approximately zero degree), and a boom housing detector 76 for detecting a state that the boom 30 is housed. When the state that the boom 30 is in the housed state is detected by the boom housing detector 75, the leveling cylinder control part 63 stops operation of the leveling cylinder 55.
KUWAJIMA KAZUO
KUBO ATSUSHI
SASAKI TAKASHI
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