Abstract: A harrow assembly having a main frame section and two wing frame sections articulated on generally fore and aft axes on opposite ends of the main frame section is disclosed herein. Each frame section has a rockshaft rotatable thereon and the rockshafts are in axial alignment when the sections are in end-to-end relation with an interconnection between adjacent ends of the respective rockshafts. The interconnection includes a pair of arms that have contacting surfaces defined thereon and the contact point between the surfaces is generally in alignment with the hinge axis between the respective sections when the assembly is in a normal earthworking position.

Abstract: An automatic reset plow assembly includes a plow frame drawn by an agricultural vehicle. A plow standard is pivotally connected to the underside of the frame to enable the plow share to pivot backwardly and upwardly upon engaging an obstruction in the soil. The plow standard is resiliently biased downwardly by a toggle link assembly having one link pivotally connected to the plow standard and a second link pivoted to the frame. The other ends of the two links are pivotally connected together and to a slide element to form the elbow of the toggle link. The slide element is slideably received along a guide member which is also pivotally mounted to the frame. A compression spring surrounds the guide and resiliently biases the slide element and toggle links to maintain the plow standard in a normally downwardly pivoted plowing position. Upon encountering an obstruction, the plow pivots rearwardly and collapses the toggle link assembly.

Abstract: A spring bias safety trip mechanism for holding a ground working tool in a fixed position with respect to a support frame is disclosed herein. The spring bias safety trip mechanism consists of a plurality of links that are interconnected in such a manner that the links act as a rigid bar between the frame and standard and collapse when excessive forces are encountered by the standard. The spring biased linkage system is designed to eliminate the need for large springs that must produce sufficient forces equal to the normal forces encountered during the normal earthworking operation.

Abstract: An automatic reset plow assembly includes a plow frame drawn by an agricultural vehicle. A plow standard is pivotally connected to the underside of the frame to enable the plow share to pivot backwardly and upwardly upon engaging an obstruction in the soil. The plow standard is resiliently biased downwardly by a toggle link assembly having one link pivotally connected to the plow standard and a second link pivoted to the frame. The other ends of the two links are pivotally connected together and to a slide element to form the elbow of the toggle link. The slide element is slideably received along a guide member which is also pivotally mounted to the frame. A compression spring surrounds the guide and resiliently biases the slide element and toggle links to maintain the plow standard in a normally downwardly pivoted plowing position. Upon encountering an obstruction, the plow pivots rearwardly and collapses the toggle link assembly.