Steuerventil,insbesondere fuer hydraulisch angetriebene Lasten

摘要

A pressure-modulating directional control valve for high-inertia loads such as the swing drive of a crane uses two three-way spool valves biased to inlet-open position and a separate pressure-regulating valve with a minimum spring bias and a manually variable hydraulic bias. Each three-way valve has a variable pilot pressure relief valve and these are alternately operable by a manual lever to modulate pilot biasing pressure applied to the pressure-regulating valve and also to one or the other of the three-way valves whenever it is acting as a brake valve in the return side of the circuit during motor overrun.