Crop cutting device for an agricultural machine comprising: a frame with a crop guiding surface having a plurality of substantially parallel slots extending in a direction of travel of the crop over the crop guiding surface, wherein the frame comprises guiding means formed as a straight, linear or curved long hole, a plurality of knives arranged side-by-side and pivotally mounted below the crop guiding surface, wherein each knife is aligned with a respective slot and is pivotable about a knife axis extending substantially perpendicular to the slots between a retracted deactivated position in which each knife is located substantially below the crop guiding surface and an extended activated position, wherein at least a cutting edge of each knife projects above said guiding surface, wherein the guiding means enable the continuous movement of the knife axis between a first stop associated with a retracted deactivated position and a second stop associated with an extended activated position; a plurality of knife protection units, each knife protection unit being pivotably connected to the frame and being configured to engage with a respective knife in the retracted deactivated position or in the extended activated position; a selector mechanism configured to selectively engage one or more of the plurality of knife protection units such that the respective knife can be brought from the retracted deactivated position into the extended activated position, the selector mechanism including a plurality of engagement elements, each engagement element configured to engage with the respective knife protection unit; wherein the knife axis is continuously moveable via the guiding means with respect to the frame; and wherein each knife by movement of the knife axis is configured to be engaged with the respective knife protection unit to assume either the extended activated position or, alternatively, the retracted deactivated position. a frame with a crop guiding surface having a plurality of substantially parallel slots extending in a direction of travel of the crop over the crop guiding surface, wherein the frame comprises guiding means formed as a straight, linear or curved long hole, a plurality of knives arranged side-by-side and pivotally mounted below the crop guiding surface, wherein each knife is aligned with a respective slot and is pivotable about a knife axis extending substantially perpendicular to the slots between a retracted deactivated position in which each knife is located substantially below the crop guiding surface and an extended activated position, wherein at least a cutting edge of each knife projects above said guiding surface, wherein the guiding means enable the continuous movement of the knife axis between a first stop associated with a retracted deactivated position and a second stop associated with an extended activated position; a plurality of knife protection units, each knife protection unit being pivotably connected to the frame and being configured to engage with a respective knife in the retracted deactivated position or in the extended activated position; a selector mechanism configured to selectively engage one or more of the plurality of knife protection units such that the respective knife can be brought from the retracted deactivated position into the extended activated position, the selector mechanism including a plurality of engagement elements, each engagement element configured to engage with the respective knife protection unit; wherein the knife axis is continuously moveable via the guiding means with respect to the frame; and wherein each knife by movement of the knife axis is configured to be engaged with the respective knife protection unit to assume either the extended activated position or, alternatively, the retracted deactivated position.