| 摘要 |
A tool assembly (10) comprises a casing section (12), and a downhole tool (14) comprising a rotary drive (16) and a cutting member (18). In use, the tool assembly (10) is disposed in a well borehole (B) and the rotary drive (16) operated to drive rotation of the cutting member (18) to cut the borehole (B). The downhole tool (14) comprises a tubular housing (20) and a cartridge assembly (36), the cartridge assembly (36) disposed within the housing (20) of the downhole tool (14) and comprising the rotary drive (16) of the downhole tool (14). A clutch (78) is provided to enable free movement of the cutting member (18) during normal operation, engagement of the clutch (78)preventing rotation of the cutting member (18)and the housing (20). |
