Method and apparatus for grinding undulate cutting edges of knives in tobacco cutting machines

摘要

The undulate cutting edges of knives on a rotary knife holder in a tobacco shredding machine are ground by a grinding wheel whose profile is complementary to that of the cutting edges and which is moved stepwise in parallelism with the axis of the holder and thereupon radially or tangentially of the holder toward and from engagement with successive portions of the knives so that the grinding wheel treats a portion of a previously treated section and an untreated section of each knife while it is held close to the path of orbital movement of the knives. An advancing mechanism is provided to shift the grinding wheel stepwise in parallelism with the axis of the holder, and a moving mechanism is provided to displace the grinding wheel toward and away from the path of orbital movement of the knives during each interval between successive advances. The grinding wheel is dressed when it is out of contact with the knives, either by a rotary dressing tool, by a stationary dressing tool whose length at least matches the axial length of the grinding wheel, or by a stationary diamond.