| 摘要 |
A rock drilling tool, such as used with a hammer drill, consists of an axially extending shank and a drilling tool head at one end of the shank which provides the rock drilling or cutting action. The drilling tool head includes a centrally positioned axially extending centering projection with at least three angularly spaced drilling fingers disposed radially outwardly from the centering projection and forming therebetween an annular recess which extends inwardly into the drilling tool head from the axial end surfaces of the drilling fingers. Each drilling finger has a drilling tooth on its axial end surface and a circle including the radially outer surfaces of the drilling teeth has a greater diameter than the diameter of the shank. The arrangement of the centering projection, the spaced drilling fingers and the annular recess affords efficient removal of drilled material and reduced friction between the hole being drilled and the drilling tool. |
