Seed planting machines

A machine for setting seeds of the type in which the seeds, fed from a receptacle to a hopper connected to the receptacle, are conveyed in cups traveling on an elevator on an endless conveyor thereof which is supported on a driven and a return sprocket of the elevator through the hopper to a furrow beneath the machine for planting therein, the cups arranged in at least two rows on the endless conveyor, each cup in one row secured on the conveyor in staggered relation with respect to each cup in an adjacent row and traveling in the rows so that the cups in one row maintain a substantially constant relationship with the cups in an adjacent row, the cups being conveyed upwardly through the hopper for loading with seed, around the return sprocket to reverse direction and to invert the cups, thereafter descending to the bottom of the machine comprising, in combination, at least one curved tube mounted on the machine in cup receiving relation adjacent the return sprocket extending from a point where the cups begin to reverse direction to a point where the cups have completely inverted and descend on the conveyor to the bottom of the machine, the tube enclosing the cups and having a shape substantially conforming to the pattern formed by the cups as they round the return sprocket and reverse direction, and means for adjustably positioning the tube relative to the cups to change the clearance between the cups and the inside walls of the tube.