| 摘要 |
The present invention relates to a rock drilling tool, a ring drill bit and an adapter for percussive drilling. The rock drilling tool (10) is intended to be connected to a casing tube (46) and a drill rod (62) in order to form a borehole. The casing tube is intended to be used as a channel for drill dust. The rock drilling tool comprises: - a drill adapter (20), including a flush duct for a flush medium, first drivers in order to transfer rotation, - a central pilot drill bit (12) provided with rock cutting members (14) and detachably connected to the first fastening means (21, 22) of the drill adapter, - a ring drill bit (17), provided with rock cutting members (41), and arranged to surround parts of the drill adapter during drilling, whereby the ring drill bit comprises second drivers intended to co-operate with the first driver of the drill adapter in order to rotate the ring drill bit with the drill adapter, and a casing shoe (18), intended to be secured to the casing tube as well as the ring drill bit, at least in connection with drilling, which casing shoe is arranged to push the casing tube only in the axial direction of the tool, whereby the casing tube (46) and the ring drill bit may be left in the borehole after finished drilling. |
