| 摘要 |
A control valve is described for use in a hydraulic steering system of an agricultural vehicle of the type having a steering valve (18) of the reactive type for controlling the supply of hydraulic fluid to jacks (26, 28) having opposed working chambers serving to move the steerable vehicle wheels (12, 14) in opposite directions. The control valve (24) is connectable between the steering valve (18) and the jacks (26, 28) and has a first setting in which fluid flow in both directions between the steering valve (18) and the working chambers of the jacking means is possible at all times and a second setting in which return flow of hydraulic fluid from any one working chamber of the jacks (26, 28) to the steering valve (18) is only possible when a positive pressure is present at the outlet of the steering valve connected by the control valve (24) to the opposed working chamber of the jacks (26, 28). <IMAGE> |
