| 摘要 |
<p>The head has primary and auxiliary blades (3, 5) with respective cutting edges (4, 6), where the edge (6) is in the form of a circular arc section (7), which runs radially from a rotation axis. The edge (5) forms a straight external section (8) radially outside to the arc section, where the external section diagonally runs in a radial manner. The external and the arc sections, and an inner section of the edge (6) are merged into one another in a smooth manner.</p> |
