Abstract: A retainer is disclosed for preventing accidental release of a knock-on earthworking tool from an adaptor secured to the tine of an agricultural implement. The retainer, which is integrally formed from a single piece of metal, comprises an anchoring portion which is retained inside a bolt hole of the of the adaptor and a tail portion which extends between the anchoring portion and an aperture in the stem of the earthworking tool. The tail of the retainer has an upturned end which catches in the aperture in the stem of the earthworking tool when the stem is wedged over the adaptor in its normal working position, thereby preventing accidental dislodgement of the earthworking tool during use.

Abstract: An agricultural sweep has an upwardly extending stem adapted to be secured to a tine of an agricultural implement and a ground breaking member comprised of a pair of substantially planar wings diverging rearwardly from a tip. In order to prevent bending or breaking of the sweep, a reinforcing ridge is provided at the juncture of the wings and the stem, the ridge extending along a longitudinal axis of the sweep from the upper surface of the wings to a point on the stem between the base and the upper end of the stem.