Drive unit for harvester blade assembly

In a blade assembly normally driven by a power takeoff shaft and having a frame normally displaced in a travel direction and provided with a pair of blade carriers horizontally reciprocal transverse to the travel direction, a drive unit comprising:

• a right-angle transmission having a horizontal input connected to the power takeoff shaft and a vertical output, the frame having upper and lower front bars forming two slots spaced apart transversely of the travel direction;
• a vertical shaft offset from the output and having a pair of angularly offset eccentrics;
• a belt drive interconnecting the transmission output and the vertical shaft;
• a pair of relatively long actuating arms extending in the travel direction, flanking the transmission and shaft on both transverse sides, and having rear ends pivoted on the frame and front ends extending through the respective slots and connected to the respective blade carriers;
• guides on the frame at the slots for the arm front ends;
• shields on the arm front ends projecting transversely of the travel direction past the slots and preventing crop from entering the slots;
• and
• a pair of respective connector plates extending transversely of the travel direction and having respective inner ends carried on the eccentrics and outer ends connected to the arms between the ends thereof.