| 摘要 |
A rock drilling tool includes a drill body on which a radially extendible reamer is mounted. The reamer, when extended, enlarges the hole diameter to enable a hole casing to be pulled down by the tool. The body includes a front pilot bit, a rear shank adapted to be connected to a drill string, and a guiding member disposed between the pilot bit and the rear shank for pulling the hole casing along with the tool. The pilot bit, the rear shank and the guiding member are non-removable from one another. The reamer, which is mounted between the guiding member and the pilot bit, is formed of two U-shaped pieces that are hinged together to enable the reamer to be installed and removed. |
