MOUNTED WORKING TOOL FOR HELICAL EXPANSION OF HOLES IN GROUND Russian patent published in 2003 - IPC

FIELD: construction equipment, expansion of vertical, inclined and horizontal holes. SUBSTANCE: mounted working tool for helical expansion of holes in ground presents shaft to which all-metal truncated cones and cylinders are made fast. They are in sequence turned through 90 degrees one relative another and their longitudinal symmetry axes are displaced in parallel to longitudinal rotation axis of working tool by 0.03 diameter of cylinder. Truncated cones and cylinders are rigidly interjoined. Height of each truncated cone or cylinder is 0.8 diameter of cylinder. Truncated cones have diameters uniformly enlarging towards cylinders. EFFECT: enhanced operational reliability and prolonged service life of mounted working tool, reduced labor input, reduced cost of its manufacture. 2 dwg