TOOL OF VARIABLE SECTION Russian patent published in 2003 - IPC

FIELD: construction industry, equipment to lay underground service lines by trench-free method. SUBSTANCE: tool of variable section comprises body of revolution with round base and hyperbolic generatrix. Generatrix of tool is positioned so that maximal radius of body of revolution does not coincide with base to achieve smooth adjustment of deviation of drilled hole with re- orientation of axis of tool relative to axis of hole. EFFECT: increased precision of driving of hole of complex profile while laying underground service lines. 1 dwg