| 摘要 |
PURPOSE: To over-cut a hard rock ground effectively. CONSTITUTION: On the periphery of a cutter head 24, a roller cutter 35 for over-cutting is installed, which can be displaced in swings by a hydraulic cylinder centering on a supporting shaft furnished on the side with the working face. In the projecting condition, the tip of the cutting edge is located on the extension of a locus 34 formed by a stationary roller cutter 33. In the accommodated condition in which the cylinder is contracted, the roller cutter for over- cutting 35 is retracted into the cutter head 24 and is free from wear. |
