ATTITUDE CONTROL DEVICE FOR PANTOGRAPH

PURPOSE: To realize a safety mechanism which does not react to very small rolling by detecting the rolling angle of a vehicle body as linear displacement through the pressure of an air spring by a pneumatic conversion cylinder for detecting the tilting angle of a vehicle body and transmitting the detected value to a pressure control valve to operate a hydraulic actuator. CONSTITUTION: Rolling angle displacement detected by a pneumatic coversion cylinder 30 for detecting the tilting angle of a vehicle body, namely, linear displacement is transmitted to the input levers 36, 37 of two pressure control valves through a link mechanism A spool inside pressure control valves 20, 21 is opened and an operating oil is made to flow into one of the cylinder chambers of a hydraulic actuator 15. Thus, the hydraulic actuator 15 is operated, whereby the spring force of the link mechanism is balanced to stop the actuator 15. As a result, a safety mechanism is realized which does not react to a very small rolling angle change and in which high reliability can be secured.