HAMMER FOR USE IN ABORE HOLE AND APPARATUS FOR USE THEREWITH

摘要

PCT No. PCT/GB85/00104 Sec. 371 Date Nov. 14, 1985 Sec. 102(e) Date Nov. 14, 1985 PCT Filed Mar. 18, 1985 PCT Pub. No. WO85/04212 PCT Pub. Date Sep. 26, 1985.Apparatus for drilling a bore hole comprising a hammer and a dual walled drill tube. The hammer comprises a reciprocable piston, fluid flow control device for directing fluid under pressure to the hammer to reciprocally drive the piston, and cutting device coupled to the hammer which rotate upon reciprocation of the hammer to cut the bore hole. Rachets are coupled to the cutting device to permit rotation of the cutting means in one direction only and to prevent rotation in an opposite direction. A portion of the fluid under pressure is diverted to entrain and direct particulate material to the surface of the bore hole.