Abstract: A hydraulic valve in a load responsive pressure flow compensated system for operating a header height cylinder including a lockout check valve which is opened by an accompanying plunger experiencing pressure in an adjacent motor port. Said plunger includes a metering notch opening to drain when the plunger is actuated, said metering notch is sized larger than the flow-sensing notch on the valve spool so that while lowering the machine header, the pressure compensating means of the system does not go to full pressure compensation level but rather stands by at the low pressure level relieved across the lockout actuating plunger. The valve further includes metering notches in the control valve spool which are so shaped that a FLOW vs. TIME curve of the spool from the neutral position to an operating position has a plateau at a time interval from zero which is substantially equal to one-half of the cycle time of the natural frequency of the machine.

Abstract: A solenoid powered flow control valve in which the valve spool has split the pump flow across a primary metering orifice and a pilot metering orifice which regardless of spool position maintains a substantially constant flow ratio between the main and pilot flow. The valve spool is controlled by opposing servo chambers which sense the pressure drop in the pilot flow path across a solenoid powered variable orifice.

Abstract: The invention is a hydrostatic device which converts rotary motion to oscillating motion for driving a sickle bar type mower by using a rotating cam plate to operate a rocker arm through a hydraulic coupling in the form of a pair of hydrostatic cylinders. The cylinders are continuously charged and due to valving openings in the pistons, the cylinders are continuously maintained in-phase with each other and the sickle bar which is being driven.