MIDDEL TIL FORBEDRING AV FLYTBARHET, EN FREMGANGSMAATE FORDETS FREMSTILLING OG DETS ANVENDELSE

摘要

PCT No. PCT/SE91/00108 Sec. 371 Date Oct. 13, 1992 Sec. 102(e) Date Oct. 13, 1992 PCT Filed Feb. 15, 1991 PCT Pub. No. WO91/12406 PCT Pub. Date Aug. 22, 1991.A down-the-hole drill tool comprises a one-piece shaft and pilot bit. The shaft is adapted for connection to a down-the-hole hammer. A reamer and a guide body are detachably mounted to the one-piece shaft/pilot bit. The guide body has a downwardly facing shoulder for pushing a casing tube downwardly along with the tool.