| 摘要 |
A carrier adapted for rotation about an axis so as to define a circular path at the outermost extension of the carrier. Anchoring means positioned on the carrier at spaced locations along said circular path. A flexible elongate member extending between and fastened to said anchoring means. At least one cutter mounted to the elongate member between a pair of the anchoring means. Said cutters extending outwardly of the circular path and maintained in said extended positions for impact cutting at least partially by the centrifugal force produced by rotation of the carrier. Said flexible member permitting rearward or inward flexing to withdraw the cutter behind the path defined by the carrier upon striking a solid object, e.g. a rock. |
