Agricultural vehicle with guided rotor knives

An agricultural vehicle, comprising:

• a chassis;
• a pickup carried by the chassis and configured to convey crop material;
• and
• a cutting assembly carried by the chassis and configured to cut crop material conveyed by the pickup, the cutting assembly comprising:
• a rotatable rotor comprising a plurality of extensions;
• a rotor floor disposed adjacent to the rotor, the rotor floor having a plurality of knife slots formed therein, the rotor floor defining a cutting side on the side of the rotor floor facing the rotor and a shielded side on the opposite side of the rotor floor;
• a plurality of movable knives disposed adjacent to the rotor floor, the knives each being movable from a cutting position to a retracted position, the knives each extending through a respective knife slot into the cutting side to cooperate with the extensions in the cutting position and being disposed on the shielded side such that the knives do not cooperate with the extensions in the retracted position, each of the knives comprising a pivot region configured to pivot about a pivot axis between the cutting position and the retracted position;
• at least one knife guide comprising a pair of spaced apart guide surfaces coupled to the rotor floor on the shielded side and defining a gap therebetween such that a respectively associated knife is at least partially disposed in the gap when in the retracted position;
• and
• a pivot guide comprising a plurality of pivot slots, each of the pivot slots being positioned adjacent to the pivot region of a respective knife and holding a portion of the respective knife.