A detection arrangement for detecting a wear status of a chopping knife arrangement of a chopping device provided for processing a product flow, wherein the chopping device has a revolving chopping drum receiving the chopping knife arrangement and at least one shear bar which cooperates with the chopping knives, with a sensor arrangement which has a magnetic exciter arrangement and a flux conducting device magnetically coupled thereto. The sensor arrangement provides a pole arrangement which forms at least one magnetic pole with a pole surface for conducting magnetic flux, wherein at least a portion of the chopping knife passes the pole arrangement during a rotation of the chopping drum. A voltage induced when a chopping knife arrangement passes the sensor arrangement forms the measured magnetic value, which is used by the evaluation unit to determine the state of wear of the chopping knife arrangement.

A detection arrangement for detecting a wear status of a chopping knife arrangement of a chopping device provided for processing a product flow, wherein the chopping device has a revolving chopping drum receiving the chopping knife arrangement and at least one shear bar which cooperates with the chopping knives, with a sensor arrangement which has a magnetic exciter arrangement and a flux conducting device magnetically coupled thereto. The sensor arrangement provides a pole arrangement which forms at least one magnetic pole with a pole surface for conducting magnetic flux, wherein at least a portion of the chopping knife passes the pole arrangement during a rotation of the chopping drum. A voltage induced when a chopping knife arrangement passes the sensor arrangement forms the measured magnetic value, which is used by the evaluation unit to determine the state of wear of the chopping knife arrangement.

A method for sharpening cutting knives carried by a cutter drum in a housing of an agricultural vehicle includes: rotating the cutter drum while keeping a sharpening door closed so an overpressure is created inside the housing, the sharpening door shielding a sharpening stone from the cutting knives while creating the overpressure; opening a transition door of the housing below the cutter drum to eject crop material through the open transition door; opening the sharpening door to expose the cutting knives to the sharpening stone and closing the transition door; grinding one or more of the cutting knives with the exposed sharpening stone; and closing the sharpening door to shield the sharpening stone from the cutting knives after grinding.

A method and a self-propelled forage harvester for determining the need for grinding chopping blades of a chopping device of the self-propelled forage harvester is disclosed. A monitoring device determines, such as cyclically, the state of wear of the chopping blades. The monitoring device comprises an input/output unit through which to enter or select a target state of the chopping blades to be produced by a grinding device as a target. The monitoring device generates, such as continuously, information depending on the target state and the determined state of wear, and causes an output on the input/output unit to visualize the extent to which the currently determined state of wear deviates from the target state.

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 forage harvester including a frame, a cutting arrangement and a plurality of displacement mechanisms. The cutting arrangement includes a cutting drum that is rotatable about a rotation axis with respect to the frame, and a shear bar holder configured to receive a shear bar attached thereto. Each of the displacement mechanisms including an actuator for displacing the shear bar with respect to the cutting drum and the frame. The displacement mechanisms include a sensor arrangement to measure one or more values representative of a force exerted on the shear bar and the shear bar holder when the cutting drum is rotating and cutting crops supplied to an area between the cutting drum and the shear bar.

A forage harvester comprising an edge sharpness detection device for detecting a degree of edge sharpness of a cutting mechanism. The cutting mechanism comminutes a stream of harvested material, with a material inflow area being defined where the cutting blades interact with the shear bar to comminute the harvested material. The edge sharpness detection device excites one or more magnetic circuits, with the respective magnetic circuit being closed by the respective cutting blade during rotation of the cutter drum once one of the cutting blades passes the magnetic assembly. The edge sharpness detection device detects the magnetic flux in the respective magnetic circuit and, based on a detected change, determines a degree of edge sharpness of the respective cutting blade. Further, the magnetic flux of the magnetic circuit may be guided lengthwise in the cutting blade at least along a longitudinal section of the respective cutting blade.