Apparatus for sharpening beet-cutter knives

A method of controlling an apparatus for sharpening a beet knife having a plurality of roof-shaped blades next to each other on a knife body, the apparatus comprising:

• a centering device carrying a centering piece and movable in a Y-direction;
• a milling device with a mechanically rotatable side miller with a roof-like milling edge movable in the Y-direction toward and away from the centering device;
• a guide extending in an X-direction substantially perpendicular to the Y-direction;
• a grab shiftable in the X-direction on the guide and designed to hold the knife to be sharpened;
• respective drives connected to the centering and milling devices for moving same toward and away from each other in the Y-direction and to the grab for moving same along the guide in the X-direction;
• and
• control means connected to the drives, the method comprising the steps of sequentially, from a starting position with the centering device and the milling device spaced from and aligned with each other in the Y-direction,
• a) moving the grab holding the knife in the X-direction to a position with a first blade of the knife directly between the centering and milling devices,
• b) advancing the centering device in the Y-direction to bring the centering piece into engagement with a back side of a first blade of the knife;
• c) advancing the milling device in the Y-direction to bring the side miller into engagement with the front side of the first blade of the knife,
• d) milling the first blade of the knife with the side miller,
• e) moving the centering device and the milling device apart in the Y-direction,
• f) stepping the grab with the knife in the X-direction through a step equal to a blade width to position a second blade of the knife between the centering and milling devices, and
• g) repeating steps a) through f) to machine the second blade of the knife.