Patent ID: 7401561

Claim:
A row crop planter having a transversely extending frame, having rearward and forward sides, which is adapted to be connected to a prime mover, comprising: a plurality of horizontally spaced-apart mounting brackets secured to the frame at the rearward side thereof; a seed planter unit positioned rearwardly of each of said mounting brackets; each of said seed planter units being secured to one of said mounting brackets by a parallel arm linkage pivotally secured to said seed planter unit and the associated mounting bracket to permit said seed planter unit to move vertically with respect to the frame; each of said parallel arm linkages comprising an upper pair of horizontally spaced-apart parallel linkage arms and a lower pair of horizontally spaced-apart parallel linkage arms; said upper and lower pairs of parallel linkage arms being vertically spaced-apart; and a fluid-filled shock absorber secured to and extending between at least some of said mounting brackets and the associated parallel arm linkage to dampen the upward and downward movement of the associated seed planter unit with respect to the frame; said shock absorber resisting the compression thereof and resisting the rebound thereof; the compression resistance of said shock absorber being greater than the rebound resistance thereof so that said shock absorber is compressed at a slower speed than it is rebounded so that said seed planter units move upwardly with respect to said frame at a slower speed than they rebound upon encountering irregular terrain or the like.