| 摘要 |
A plurality of individual tools mounted on a rotating head of a continuous drilling machine are each supported by a tool holder which is angularly oscillated at constant amplitude about an axis perpendicular in space to that of the rotating head. The oscillating axis for each tool is at the same radius with respect to the axis of the rotating head, and the oscillatory movement of each tool holder is circumferentially offset with respect to the other tool holders to insure the simultaneous sweeping of four concentric zones corresponding to the advance of conical form of the cutting front. Means are provided to exert periodic forces to produce a discontinuous advance of the tool upon each change in the direction of movement of the tool holder. |
