Parallelogram link guide system for knife blade moved through soil in field is used in conjunction with spring skid sliding along surface of soil and has wires forming parallel links

摘要

The agricultural tool has a knife blade (4) pulled through the soil at a constant depth below the surface (14). The knife blade has a vertical rod fitting telescopically in a sleeve (3) with a clamping screw (15) to give vertical adjustment. The parallelogram linkage connecting the sleeve to a frame (6,9-11) with side lugs (12) consists of a top wire (8) and two lower wires (7a,b) side-by-side, all under tension. The machine frame holds a curved leaf spring (1,1a) with a skid (2) on its underside, sliding over the surface of the soil. The end of the spring fits in a pocket (5) in the sleeve holding the knife blade and keeps the parallelogram linkage wires in tension.