DITCHER

PURPOSE:To increase excavation strength by providing fly-wheels and sprockets through a decelerator to a hydraulic motor shaft of a ditcher, and coping with overload by means of moment of inertia of the fly-wheels and high torque through the decelerator. CONSTITUTION:Fly-wheels 20 are loaded to a rotary shaft of a hydraulic motor mounted to a ditcher body 6, and sprockets are connected therewith through a decelerator 19. After that, when the sprocket 13 is rotated and driven by operating the hydraulic motor 18, bits 17 rotating around the sprockets 13 and 14 excavate a bedrock for ditches. When the bits 17 strike against a hard rock during the excavation, high torque is applied to the sprocket 13 against overload by the increase of torque of the sprocket 13 by high speed operation of the hydraulic motor 18 and moment of inertia of the fly-wheels 20. According to the constitution, excavation force increases, and excavation can be efficiently made.