METHOD FOR PROTECTING SOLENOID CAPABLE OF ELECTRICALLY CONTROLLING POSITION OF TILLAGE MACHINE BODY OF TRACTOR

PURPOSE:To prevent an accident, such as trouble of heating due to misapplication of a continuous voltage to solenoids, by determining ON or OFF of a solenoid capable of electrically controlling a changeover valve based on results of given operation processing in a controlling part. CONSTITUTION:Operation of a supporting mechanism for connecting a car body 1 to a tiller body 2 is controlled by a controlling part 4. Automatic regulating operation is performed to provide a good position of the tiller body 2 by action of sensors 111 and 112 for sensing tilt of lift arms 121 and 122 and a horizontal posture holding sensor 13 in the normal tillage state. When normal operation was not performed, application of a voltage to solenoids 811, 812, 821 and 822 is directly stopped to enable operation after attaining the normal state.