Patent ID: 7992374
Filing Date: 2011-08-09
Classification: A01D

Abstract:
1. A header for an agricultural plant cutting machine, comprising: an elongate floor; a plurality of elongate support arms operably connected to the floor and supporting a flexible cutterbar for upward and downward movement relative to the floor, the support arms being configured to have a variable length for varying a fore and aft position of the cutterbar relative to the floor; adjustable biasing elements connected between the floor and at least some of the support arms, respectively, the biasing elements being configured and operable for yieldably exerting a preload force against the support arms, respectively, urging the cutterbar upwardly or downwardly; and a preload adjusting system in connection with the adjustable biasing elements and the cutterbar configured to automatically vary the preload force as a function of the fore and aft position of the cutter bar, wherein at least one of the support arms comprises a rack carrying a portion of the cutterbar and movable in a fore and aft direction relative to the floor for changing the fore and aft position of the portion of the cutterbar, and wherein the preload adjusting system comprises a pinion in an enmeshed connection with the rack or the cutterbar, configured to move in a manner corresponding to the fore and aft movements of the cutterbar, such that the movement in the manner corresponding to the fore and aft movements will comprise a rotary movement of the pinion.