Patent ID: 6578642
Filing Date: 2003-06-17
Classification: A01B

Abstract:
A tillage implement having a generally transversely extending main frame supported by lift wheel structure for forward movement over a field, the implement including tool structure for penetrating the ground, a trailing attachment for working the ground behind the tool structure comprising:a trailing support arm connected to the frame and extending rearwardly therefrom to an aft end; an attachment frame connected to the aft end and including trailing tools for engaging the ground behind the tool structure, the support members and trailing tools providing sufficient weight to establish down pressure for ground penetration of the trailing tools independently of additional down pressure structures; hydraulic lift structure including a single acting hydraulic cylinder having first and second ends and connected between the main frame and the support arms and operable to lift the trailing implement relative to the frame; a stop member preventing lowering of the attachment frame below a lowermost position; a control valve connected to a source of hydraulic fluid under pressure and having raise, lower and neutral positions; a hydraulic line operably connecting the control valve to the first end of the cylinder; wherein the control valve, in the raise position, operates the cylinder to lift the trailing attachment toward an uppermost position, and in the lower position allows the trailing attachment to lower under the force of gravity toward the lowermost position, and in the neutral position blocks hydraulic fluid from passing to and from the cylinder to generally maintain the attachment in a selected operating position relative to the frame, the selected operating position lying within a range from the lowermost position to an upper operating position below the uppermost position; and wherein lift forces on the attachment establish a pressure differential in the hydraulic line to permit the attachment to lift relative to the main frame from the selected operating position, even when the valve is the neutral position, when the lift forces exceed the force of gravity on the attachment, so that forces transferred to the main frame from the attachment frame are limited.