Abstract: Device for mowing crops, comprising a series of mowing units arranged side by side at predetermined distances, each mowing unit comprising a knife holder with at least one knife carrying portion for carrying a mowing knife, and a drive mechanism for each knife holder. The drive mechanism for each knife holder comprises a first drive element comprising a hub portion for carrying the respective knife holder, and a second drive element drivingly engaged with the first drive element to rotatingly drive the knife holder about a vertical axis. In normal operation, the knife holder and the hub portion form a unitary rotatable assembly which, at a position between the knife carrying portion and the hub portion, is provided with a break connection which is effective in a radial direction.