Positive neutral control for hydrostatic transmission

摘要

A hydrostatic transmission includes a reversible, variable displacement pump having a swashplate actuator controlled by a pilot-operated displacement control valve. A manually operated displacement control lever is manipulated to opposite sides of a neutral position to effect command signals for causing pilot operation of the displacement control valve to control movement of the swashplate in accordance with the command. A neutral control valve is coupled to the displacement control lever and is operated thereby to a neutral position, wherein it connects the swashplate actuator to sump, when the lever is moved to its neutral position.