Device for sharpening rotary blades

A device for sharpening a cutting edge of a planar rotary blade turning about a fixed axis of rotation, as utilized in cigarette manufacturing machinery and having a known typical rate of wear when used for cutting a particular material, said device comprising:

• a pair of mutually coaxial grinding wheels set at a distance one from the other such as to afford a recess accommodating at least the cutting edge of a blade to be sharpened, said grinding wheels being angled in relation to the plane occupied by the blade, said grinding wheels being rotatable about their common longitudinal axis;
• a support capable of movement through a rectilinear trajectory parallel with the plane occupied by the blade, said grinding wheels being mounted to said support for movement therewith;
• drive means, by which said grinding wheel support is set in motion along said trajectory at least when moving toward the blade;
• monitoring and control means, programmable in respect of said known typical rate of wear or loss of cutting edge of the rotary blade and automatic in operation, to which the drive means are interlocked for setting said grinding wheel support in motion depending upon said known typical rate of wear or loss of cutting edge, in accordance with a program residing in said monitoring and control means, said monitoring and control means further including means designed to sense a totally worn condition of the rotary blade and thereupon to inhibit operation of the drive means, wherein the totally worn condition corresponds to the minimum working diameter of the blade.