Agricultural System

Abstract

A hydraulic control system for controlling the down force on an agricultural implement comprises a hydraulic cylinder containing a movable ram, a source of pressurized fluid coupled to the hydraulic cylinder on a first side of the ram by a first controllable valve, a fluid sump coupled to the hydraulic cylinder on the first side of the ram by a second controllable valve, and an electrical controller coupled to the valves for opening and closing the valves. The valves may be self-latching valves that remain in an open or closed position until moved to the other position in response to a signal from the controller.

1 . An agricultural row unit comprising
 a frame having a gauge wheel that engages the soil to control the elevation of the frame,   a soil-engaging tool coupled to said frame to permit vertical movement of said tool relative to said frame,   a hydraulic cylinder having a movable rod and containing a pressurized hydraulic fluid for applying a down force to said frame or said tool to urge the tool into the soil,   an uplift accumulator housed within said rod and exposed to said hydraulic fluid to permit upward movement of said tool in response to increased resistance by the soil to downward movement of said tool, while applying a force resisting said upward movement of said tool, and   a down pressure accumulator coupled to said hydraulic cylinder to permit downward movement of said tool in response to decreased resistance by the soil to downward movement of said tool, while applying a force resisting said downward movement of said tool.   
     
     
         2 - 21 . (canceled)