Abstract: A device for computer aided surgery, including: a body; an optical element coupled to the body; a fiducial coupled to the body; and a calibration element. The calibration element be a pointer tip or a divot, either individually or in combination.

Abstract: An agricultural seeding machine movable in a planting direction includes a frame; a disc opener assembly carried by the frame and having a first axis of rotation; a gauge wheel assembly carried by the frame and having a second axis of rotation, and a press wheel assembly carried by the frame and having a third axis of rotation. The second axis is positioned forward of the first axis relative to the planting direction. The gauge wheel assembly overlaps the disc opener assembly relative to the planting direction. The third axis is positioned rearward of the first axis relative to the planting direction. The press wheel assembly overlaps the disc opener assembly relative to the planting direction.

Abstract: A disk assembly for an agricultural implement includes a hub; a disk mounted to the hub; an axle having outer threads; a sleeve having inner threads engaged with the outer threads on the axle; and a bearing assembly having an outer race adjacent the hub and an inner race adjacent the sleeve.

Abstract: A mutually-engageable or interlocking connection between a seed tube guard and a frame member mounted to a seed planting machine. The mutually-engageable connection includes a yoke having a front journal and a rear journal with a gap, the yoke, carried on the frame member, and a pin connected to a neck, carried by the guard. The pin is sized to fit between and into the front and rear journals, wherein the neck has a thickness less than a width of the gap in order to slide though the gap during installation, and a length to fit between and through the front and rear journals.