To enhance a grounding load of a crawler to the utmost to increase its tractive force by arranging a position of a roller frontward during going- down of a working machine, and increase a grounding load of a front wheel to stably operate a body by widening a space between the front wheel and the roller in a lifted condition of the machine.
In a semi-crawler type tractor provided with a pair of left and right wheel-type front wheels 1, 1 and crawler type rear traveling devices 2, 2, and connected with a working machine 3 to a rear end portion of a body freely to be liftable, a crawler 46 is laid over among a driving wheel 32 provided in a driving shaft 4 protruded to a body side and driven wheels 5, 6 arranged respectively in front and rear sides below the wheel 32 in the device 2, rollers 7F, 7R are provided between the wheels 5, 6, and a position of the rollers 7F, 7R are freely changed by a hydraulic cylinder 9.
ISHIMARU HIDEJI
KOYAMA KOJI
KATAUE NOZOMI
