Earthworking apparatus

Claim 1

In a planting apparatus adapted to be connected to a propelling machine, such as a tractor, and including a supporting frame means, planting furrow opening means carried by said supporting frame means for opening a furrow and being mounted for swinging vertical movement relative to said support frame upon engagement with surface irregularities and obstructions, press wheel means carried by said supporting frame means for closing a furrow opened by said opening means and being mounted for swinging vertical movement relative to said supporting frame means upon engagement with surface irregularities and obstructions, and seed dispensing means operatively connected to said press wheel means for depositing seed into a planting furrow opened by said furrow opening means prior to closure of the furrow by said press wheel means; the improvement therewith of earthworking means carried by said supporting frame means forwardly of said planting furrow opening means and being characterized by the ability of the earthworking portion thereof to move from an earthworking operative position to a nonearthworking inoperative position upon encountering an excessive draft condition for preventing damage thereto and to return to said earthworking operative position upon the removal of said excessive draft condition, said earthworking means comprising, a bell crank foot piece pivotally suspended at one end thereof from said supporting frame means, an earthworking tool operatively secured to the other end of said bell crank foot piece and being movable with said bell crank foot piece to swing in a generally vertical direction between an earthworking operative position and a nonearthworking inoperative position, a toggle mechanism interconnecting said bell crank foot piece intermediate the ends thereof with said supporting frame means, said toggle mechanism including toggle links movable from a substantially on-center position in the earthworking operative position of said earthworking tool to an off-center position in the non-earthworking inoperative position of said earthworking tool, and spring means operatively connected to the fulcrum of said toggle links for urging said toggle links toward said substantially on-center position to restrainingly maintain said earthworking tool in the operative position, while allowing said toggle links to trip and move to said off-center position while said earthworking tool moves to said non-earthworking inoperative position and to urge the return of said toggle links and earthworking tool to said substantially on-center and earthworking operative positions, respectively, upon removal of said excessive draft condition.