Patent ID: 6698523
Filing Date: 2004-03-02
Classification: A01B,F15B

Abstract:
In an agricultural implement having a frame supported by a plurality of movable lift assemblies for raising and lowering the frame relative to the ground, a lift control system for controlling flow of pressurized hydraulic fluid from a supply line and flow of hydraulic fluid into a tank return line, said lift control system comprising:a first hydraulic line and a second hydraulic line; a primary control valve which selectively connects the first hydraulic line and the second hydraulic line to the supply line and the tank return line; a plurality of hydraulic cylinders, each mechanically coupled to the agricultural implement to produce movement of a different one of the plurality of vertically movable lift assemblies with respect to the frame, each of the plurality of hydraulic cylinders having a first port and a second port; the plurality of hydraulic cylinders hydraulically connected in a series between the first hydraulic line and the second hydraulic line, wherein a first hydraulic cylinder in the series has a first port connected directly to the first hydraulic line, each hydraulic cylinder, except for a last hydraulic cylinder in the series, has its second port connected to a next hydraulic cylinder in the series, and the last hydraulic cylinder in the series has its second port connected to the second hydraulic line; and a plurality of two-position lift controls valves, each connected between the first and second ports of one of the plurality of hydraulic cylinders.