Patent ID: 8056465
Filing Date: 2011-11-15
Classification: A01B,A01C

Abstract:
1. An improvement in an active hydraulic down pressure system for an agricultural implement having down pressure cylinder structure and operable in an automatically controlled down pressure mode, the system also including a hydraulically powered device and a source of hydraulic fluid under pressure, a first multi-position selective control valve connected between a fluid output on the source and the hydraulically powered device, a multi-position operator selective control valve connected between the source and the down pressure cylinder structure and including an adjustable pressure valve having an input connected between the operator selective control valve for maintaining down pressure of the cylinder structure at a preselected level, the operator selective control valve having a raise, a lower and a float position, the improvement comprising a check valve connected between the operator selective control valve and the adjustable pressure valve, and a fluid line connected to the fluid output on the source and to the input of the adjustable pressure valve downstream of the check valve, the fluid line providing a source of hydraulic fluid under pressure to the adjustable pressure valve independently of hydraulic fluid under pressure from the operator selective control valve so that the operator selective control valve is operable in the float position while the implement is operating in the automatically controlled down pressure mode.