UNDERWATER EXCAVATION DEVICE

PURPOSE:To exhaust all muck including stones, etc., produced from pit excavating works smoothly only with an air lift by allowing a pair of rotary drum cutters to pinch such stones left at the bottom of a pit being excavated or large lumps of marine ground, and thereby crushing into smaller pieces. CONSTITUTION:The body 3 of an underwater pit excavating machine is passed through a steel pipe pile 8, hung down from the top, and fixed to the inner wall of the pipe pile 8 using a gripper 16. A pair of drum cutters 24, 24 are revolved round the axis of a pit excavated by a hydraulic motor 18 and a speed reduction gear 19 for revolutions through a revolving inner cylinder 17, revolving support member 4, and swing arm 5 and are rotated in the opposite directions to each other by an oil pressure pump installed on the swing arm 5. Accordingly stones, etc., produced from the excavation works are hitched by a pick 24c, nipped by the cutters 24, 24, crushed into smaller pieces, sucked into a muck suction part 31 through the action of an air lift together with the excavation muck, and exhausted.