Rock guard for quick change knives on a disc mower

A rock guard for rotary disc cutters used on an agricultural cutterbar for severing a standing crop from the ground while being propelled in a forward direction, the rock guard comprising:

• a plurality of rotary disc cutters configured for synchronized rotation about a plurality of spaced apart generally upstanding rotational axes, each cutter having a rotating disc;
• a pair of knives removably mounted on each of the plurality of rotating discs, the pair of knives mounted in diametric opposition defining a knife axis therebetween, respective knife axes on adjacent rotary discs being rotationally offset by a stagger angle;
• a pair of quick connectors attached to each rotary disc for removably mounting the respective pair of knives to each rotary disc, each quick connector allowing selective removal of the respective knife by downward movement parallel to the rotational axis to disengage the knife from the quick connector;
• and
• a rock guard disposed adjacently beneath each of the plurality of rotary disc cutters, the rock guard having an upper surface generally parallel to and spaced apart from a plane defined by rotation of the respective pairs of knives, spacing between the upper surface and the plane of knife rotation being insufficient to permit knife removal, the rock guard further having a leading edge and a first access channel in the upper surface having a depth spaced to the plane of the rotating knives which allows knife removal, the first access channel aligned on a first radial axis from the rotational axis, the first radial axis oriented such that more than one quarter of the knives on the cutterbar may be simultaneously aligned with the respective first access channels on the plurality of rock guards.