DEVICE FOR DRILLING WELLS IN GROUND Russian patent published in 1995 - IPC

FIELD: mining industry. SUBSTANCE: device has a hollow casing, a working tool with conic frontal part 1, tail thrust member 7 and a system for supplying compressed medium provided with ducts and main pipe communicating with the casing cavity and the tail thrust member. The device has frontal thrust member 6 and rod 2 with ducts and ring-shaped pistons 8 with constraint edges 9 fixed on their surface, the rod being attached to the working tool. The casing to assemblies 3 and 4, four sections 5 with stoppers. Frontal thrust member 6 is between the assemblies 3 and 4 of the casing, which diameter is greater than that of the base of conic frontal part 1 of the working tool. The system for supplying compressed medium has medium supply delay units 30-32 and an additional line connected with the cavities of each of sections 5 and frontal thrust member 6. The main line is connected with the section of rear assembly of the casing. Outlets 19 of the ducts of the main line are on rod 2 more close to the tail thrust member relative to ring-shaped pistons 8. Outlets 20 of the additional line are on the working tool side with respect to the ring-shaped pistons. EFFECT: enhanced effectiveness in tunnelling closed wells in ground. 6 cl, 3 dwg