| 摘要 |
On the end of the inner pipe (9-11) facing the drilling crown is located a casing (12) with a core catchment ring (13). The casing is axially displaceable relative to the inner pipe to locate against, and support the drilling crown and/or a part (14) of the outer pipe. This support action is required when the core pipe with its two constituents is drawn out of the hole for extraction of the drilling core contained in the inner pipe. The core catchment casing is releasably connected to the inner pipe (9-11) to move with is during the drawing-out process, and then permit their separation. |
