Control device for load-independent feed control for pressure-medium-operated consumers

摘要

The invention relates to a control device for load-independent feed control for at least two pressure-medium operated consumers connected in parallel, in which a directional control valve is allocated to each consumer, and a pressure-difference valve is provided between feed line and discharge line. The invention is to eliminate impairment of the control sensitivity and the operating reliability of the directional control valves and at the same time ensure trouble-free operation of several consumers with different loading. The object of the invention is to create such a control device in which no unfavourable effect of transverse forces on the spools of the directional control valves occurs and in which it is ensured that, when a second consumer is connected to an already connected consumer, the undiminished pressure of the consumer subjected to the higher load is always applied in the spring space of the pressure-difference valve and sensitive control of the consumer in each case subjected to the low load is also possible. This is achieved by the connection according to the invention between the spring space and the discharge line or in each case one of the two allocated consumer lines via the centre annular control passage of three annular control passages arranged next to one another in each directional control valve. <IMAGE>