Vorsteuerung für zwei hydraulisch betätigbare Wegeventile

摘要

The invention relates to a pilot control for two hydraulically actuatable distribution valves (11, 12) with a hydraulic (51) or electric (75) pilot control device. To move a first distribution valve (11) from a neutral position in opposite directions, it has a handle (56) which can be moved from a neutral position in various directions. The pilot control device or two electrically adjustable pilot valves have two control outputs (78, 18) via which a pilot control pressure can be applied to a first control pressure chamber (17) in the first distribution valve (11) for adjustment in one direction and a second control pressure chamber (18) for adjustment in the other direction. Particularly to obtain a less complex and cheaper pilot control for the case where it is unnecessary or undesired for both distribution valves to be actuated at the same time, there is an electromagnetically operable changeover valve (22) which connects one control output (78) of the pilot control device (51) or an electrically adjustable pilot control valve (77) in its first switching position to a control pressure chamber (17) in the first distribution valve (11) and to one in the second valve (12) in its second position. The pilot control device is thus simplified or the number of electrically adjustable pilot control valves is reduced.