METHOD OF FORMING PASSAGES OF SMALL DIAMETERS, MAINLY IN CONCRETE OR IN STONE AND DEVICE FOR REALIZATION OF THIS METHOD Russian patent published in 2001 - IPC

FIELD: construction engineering; forming passages of small diameters in concrete or in stone; cleaning internal surfaces of tubular members from solid deposits. SUBSTANCE: proposed method consists in applying static load of 5 to 15 kg/sq.cm to cutting tool in the course of operation; load is applied along longitudinal axis of tool and coolant is fed to cutting tool under pressure P equal to 0.5 to 10.0 kg/sq.cm; axial impact power pulses are generated in coolant at frequency of 5 to 50 Hz. Simultaneously, cutting tool is centered relative to inner surface of passage being formed through forming the effect of hydraulic wedge between surface of passage being formed and lateral surface of centering shaped part of spindle extension in form of rod with oval cross section. Device for forming the passages of small cross section includes body with coolant supply pipe union inside which fixed bush is fitted; this bush embraces spindle connected with rotation drive and provided with extension in form of rod with centering shaped part with oval cross section at free end. Fixed bush has collector on external surface in form of circular groove connected with pipe union; this groove is connected with through passages of spindle and rod embraced by it by means of radial passages. Tipped cutting tool is secured on free end of rod. EFFECT: increased productivity; improved quality of surface; reduced labor consumption. 4 cl, 3 dwg