| 摘要 |
A field marker is provided for mounting on an agricultural implement fo r generating a marked line on the ground parallel to a direction of movement o f the implement. The marker includes an arm with a marker disk at the outer end an d a mounting assembly arranged such that the arm, in a working position thereof, is maintained projecting outwardly from one side of the implement and can pivot about a horizontal axis substantially parallel to the direction of movement such that the arm and ground working element can move vertically to accommodate variations in ground height. The arm can fold inwardly about a generally vertical axis to move a folded position along the side of the implement substantially parallel to sa id longitudinal axis. The arm is moved by a scissors lever arrangement includin g first and second levers and a cylinder for effecting folding of the levers about vertical axes parallel to the folding axis of the arm to a position inwardly of the a rm and on top of an elongate mounting bar attached to the implement. The scissors lift provides increased stability of the arm particularly for longer arms necessa ry for wider implements. A spring force tending to lift the arm has a normal value for floating during operation and an increased value during folding to reduce dr ag as the arm folds inwardly. The spring force is provided by one spring at the arm an d a supplemental spring at the scissors. The spring force is increased during folding by a second cylinder linked to the scissors cylinder with pivots an arm on the scissors to move an outer end of the supplemental spring to increase the spring force of that spring.
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