Abstract: Drive mechanism for a four-wheel-drive tractor, comprising a pair of input shafts in double tube construction with one fitted to nest in the other, main gearing shaft assembly, differential gearing, front-wheel-drive-shaft assembly, gearing wheels provided in both frontal and rear portions of the front-wheel-drive-shaft assembly, a power-take-off shaft and a drive shaft-assembly. Driving power taken out from the gearing wheel provided in front portion of the front-wheel-drive-shaft assembly is transmitted to front wheels via a transmission shaft with a mating gear, disposed at an underbelly portion of the tractor. The drive assembly is provided above the differential gearing. With this construction, the front-wheel-drive-shaft can be made short, sufficient empty space height can be provided in the underbelly portion of the tractor, and the transmission housing can be minimized.

Abstract: Hydraulic control system including a bypass provided in an intermediate portion of an oil passage extending from a position control valve to a hydraulic actuator for raising and lowering a working implement. A draft control valve disposed in the bypass controls the pressure of oil flowing into the bypass, in response to the displacement of a member for sensing the draft force of the working implement.