PURPOSE: To automatically maintain a machine body of a farm tractor in a horizontal or substantially horizontal position regardless of ground conditions to reduce fatigue of a driver of the farm tractor by providing the farm tractor with actuating devices for moving four wheels up and down individually relative to the machine body to maintain the machine body always in a horizontal position.
CONSTITUTION: Front wheels 1a, 1b actuatable by respective hydraulic motors M1 and rear wheels 2a, 2b actuatable by a common hydraulic motor M2 are designed to be moved up and down relative to a machine body by means of hydraulic cylinders 5, 7, 8. A control valve V1 for the cylinder 8 can be operated by a manually operable member 10 while other control valves V2 for the cylinders 5, 7 have each an electromagnetic operating part 11 which is controlled by a valve operating mechanism 13 in response to an output of a device 12 for detecting an inclination in a forward and a backward direction and in a leftward and a rightward direction of a self-travelling machine body. Additionally, an alarm mechanism 32 is provided in a controlling station whereby a buzzer 23 or 24 is operated when an inclined angle of the machine body is less than a predetermined level.
HASHIMOTO OSAMI
OKUYAMA SHIGEAKI
