Drawbar for connecting tractor vehicle and trailer, has hydraulic system whose valves are active in one state to adjust height of drawbar and non-active and block hydraulic fluid in chambers of actuator, in another state

摘要

The drawbar has an actuator (26) i.e. hydraulically actuating cylinder, comprising two chambers (V1, V2), which are supplied with hydraulic fluid. A hydraulic system comprises two valves (48.1, 48.2). One valve is connected to one chamber and another valve is connected to another chamber. The valves occupy two states. The valves are active in one state to adjust height of the drawbar. The valves are non-active and block the hydraulic fluid in the chambers, in another state to immobilize the drawbar in a predetermined position.