| 摘要 |
Apparatus for grinding twist drills comprises a drive shaft and a grinding wheel, which is coupled to said shaft and is mounted thereon to be axially movable relative to the shaft and is spring-loaded toward a drill-guiding structure facing the grinding surface of the grinding wheel. The drill-guiding structure comprises guiding passages for guiding drills differing in diameter against the grinding surface and in association with each guiding passage comprises at least one guide lug for extending into a flute of the twist drill extending through the associated guiding passage, and a drill stop for limiting the advance of the twist drill in the guiding passage against the elastically yielding grinding wheel. To said drill-guiding structure at least one abutment is connected which is engageable by the grinding wheel and has a higher hardness than the grinding wheel. That abutment has an abutment surface which is parallel to the grinding surface of the grinding wheel and is engageable by said grinding surface to limit the displacement of the grinding surface toward the drill-guiding structure under spring force in an end position in which the grinding surface is closer to the guide lugs than the drill stop. The provision of said abutment ensures that the wear of the grinding wheel will not change the position of the grinding wheel relative to the drill-guiding structure and that the grinding surface will be restored substantially to its original shape when the grinding surface has been subjected to irregular wear. |
