| 摘要 |
A drill section, in which additionally in the front of a coulter on an extension of a U-like bracket a extendable spring–loaded knife of a wedge-like cross-section, symmetrical as regards to a longitudinal–vertical plane is mounted in such a manner as to allow adjusting thereof according to the stroke in soil. The side walls of the knife are made as logarithmic spirals, concave to the plane of symmetry thereof, the curvature of which is increased from the front cutter edge of the knife to back side thereof. |
