A grinding device and a grinding method for grinding at least one knife. The grinding device includes a frame with a knife holder and a grinding unit comprising a grinding head, a grinding head holder, and a grinding head drive assembly. The grinding unit can selectively be connected with the frame or can be disconnected from the frame and can be placed on a cutting assembly with knives to be ground. In both operating modes the grinding head drive assembly rotates the grinding head and moves the rotating grinding head with respect to the grinding head holder.

A grinding device and a grinding method for grinding at least one knife. The grinding device includes a frame with a knife holder and a grinding unit comprising a grinding head, a grinding head holder, and a grinding head drive assembly. The grinding unit can selectively be connected with the frame or can be disconnected from the frame and can be placed on a cutting assembly with knives to be ground. In both operating modes the grinding head drive assembly rotates the grinding head and moves the rotating grinding head with respect to the grinding head holder.

A method for determining the sharpness of cutting edges (16) of chopper blades (1) at a rotationally driven chopper drum (14) of a forage harvester includes scanning a blade surface of at least one of the chopper blades located behind the cutting edge by at least one electrode operating as a contact sensor and determining a duration of contact of the at least one electrode with the blade surface.

A method for determining the sharpness of cutting edges (16) of chopper blades (1) at a rotationally driven chopper drum (14) of a forage harvester includes scanning a blade surface of at least one of the chopper blades located behind the cutting edge by at least one electrode operating as a contact sensor and determining a duration of contact of the at least one electrode with the blade surface.

A grinding device and a grinding method for grinding at least one knife. The grinding device includes a frame with a knife holder and a grinding unit comprising a grinding head, a grinding head holder, and a grinding head drive assembly. The grinding unit can selectively be connected with the frame or can be disconnected from the frame and can be placed on a cutting assembly with knives to be ground. In both operating modes the grinding head drive assembly rotates the grinding head and moves the rotating grinding head with respect to the grinding head holder.

A grinding device and a grinding method for grinding at least one knife. The grinding device includes a frame with a knife holder and a grinding unit comprising a grinding head, a grinding head holder, and a grinding head drive assembly. The grinding unit can selectively be connected with the frame or can be disconnected from the frame and can be placed on a cutting assembly with knives to be ground. In both operating modes the grinding head drive assembly rotates the grinding head and moves the rotating grinding head with respect to the grinding head holder.